Paediatric

Question 1

1. A ten year old boy complaining of generalised back pain is referred by his GP for a
   thoracic spine plain film which shows anterior vertebral body scalloping. Which of the
   following would be a cause of anterior vertebral body scalloping?
   a. Neurofibromatosis
   b. Acromegaly
   c. Achondroplasia
   d. Ehlers–Danlos syndrome
   e. Down’s syndrome

Answer 1

1. e. Down’s syndrome
   Anterior vertebral body scalloping is seen in Down’s syndrome. Posterior scalloping is seen
   in syringomyelia, Marfan’s, Hurler’s, Morquio’s, osteogenesis imperfecta and communicating
   hydrocephalus. In Down’s syndrome there is also squaring of the vertebral bodies,
   and atlanto-axial subluxation occurs in approximately 25% of cases

Question 2

2. A ten day old baby is referred for a hip ultrasound as clinical examination has revealed a
   ‘clicky’ right hip. Which of the following parameters is reassuring for a normal hip joint?
   a. Alpha angle >60
   b. Alpha angle <60
   c. Beta angle >77
   d. 25% coverage of the femoral head
   e. Acetabular angle >30

Answer 2

2. a. Alpha angle >60°
   Alpha angle should measure >60 in a normal hip. Acetabular angle >30 strongly suggests
   dysplasia. Beta angle should measure less than 77. The alpha angle is the line between the
   straight edge of the ilium and the bony acetabular margin. The beta angle is the angle
   between the straight lateral edge of the ilium and the fibrocartilagenous acetabulum. Over
   58% coverage of the femoral head is considered normal, 33–58% coverage is indeterminate
   and less than 33% is abnormal

Question 3

3. A two week old neonate presents with central cyanosis and respiratory distress. Plain
   chest radiograph reveals pulmonary plethora. Which is the most likely underlying congenital
   heart disease?
   a. VSD
   b. Tetralogy of Fallot
   c. PDA
   d. Pulmonary stenosis
   e. Total anomalous pulmonary venous return (TAPVC)

Answer 3

3. e. Total anomalous pulmonary venous return (TAPVC)
   VSD and PDA will both result in pulmonary plethora and distress, but are left-to-right
   shunts and acyanotic. Pulmonary stenosis results in pulmonary oligaemia and may or may
   not be cyanotic depending on the presence of an intracardiac defect with shunt reversal.
   Tetralogy of Fallot is a congenital cyanotic heart disease with pulmonary oligaemia unless
   associated with the development of aorto-pulmonary collaterals. Apart from TAPVC, the
   admixture lesions such as truncus arteriosus, tricuspid atresia, transposition of great vessels,
   single ventricle and common atrium are some other causes of cyanosis with pulmonary
   plethora.

Question 4

4. A 16 year old presents with recurrent pneumothoraces. Past history reveals the presence
   of a lytic lesion of the parietal bone with a tender soft-tissue mass. Which of the
   following features is most likely seen on HRCT?
   a. Evenly distributed smooth thin-walled cysts
   b. Centrilobular nodules
   c. Extensive paraseptal emphysema with bulla formation
   d. Sparing of the apices
   e. Cystic lesions along the course of the bronchial tree

Answer 4

4. b. Centrilobular nodules
   The patient had an eosinophilic granuloma and presented with recurrent pneumothoraces
   due to Langerhans’ cell histiocytosis, which is characterised by centrilobular nodules which
   cavitate, initially forming thick-walled and then thin-walled cysts. The fibrosis that follows
   typically involves the upper zones. Cystic lesions along the bronchial tree are a feature of
   cystic bronchiectasis.

Question 5

5. A ten year old boy presents with a history of progressive gait abnormalities. Plain
   radiographs of the thoraco-lumbar spine show widening of the spinal canal at T8-L1.
   MRI demonstrates an eccentric, ill-defined, homogeneous intramedullary lesion which is hypointense to the cord on T1 and hyperintense on T2. There is patchy, irregular
   enhancement post-contrast. What is the most likely diagnosis?
   a. Lipoma
   b. Ependymoma
   c. Astrocytoma
   d. Ganglioglioma
   e. Haemangioblastoma

Answer 5

5. c. Astrocytoma
   Astrocytoma of the spinal cord is the most common intramedullary neoplasm in children.
   They most commonly occur in the thoracic region (thoracic 67%, cervical 49%, conus
   medullaris 3%). The most common presentation is with pain and sensory deficit but they
   can also present with motor and gait abnormalities. Plain radiographs may demonstrate
   scoliosis, bone erosion and widened interpedicular distance.
   On MRI, the lesion is usually seen as an eccentric, homogeneous, extensive, ill-defined
   cord tumour that is iso- or hypointense to the cord on T1 and hyperintense in T2. There is
   patchy irregular gadolinium enhancement. Tumour cysts and syrinx are also common.
   Patients with low-grade astrocytomas have a 95% five-year survival.
   It is often difficult to differentiate an astrocytoma from ependymoma of the spinal cord
   on imaging. In this case, the age of the patient, tumour location, tumour irregularity and
   eccentric position within the medullar favour astrocytoma.

Question 6

6. A two year old girl presents with recurrent headaches, neck pain and vomiting. She is
   found to have kyphoscoliosis and café-au-lait spots. CT brain shows a mostly cystic mass
   within the right cerebellar hemisphere. There is some calcification. After contrast, there
   is enhancement of the cystic wall and strong enhancement of a mural nodule. The most
   likely diagnosis is:
   a. Haemangioblastoma
   b. Medulloblastoma
   c. Metastasis
   d. Pilocytic astrocytoma
   e. Arachnoid cyst

Answer 6

6. d. Pilocytic astrocytoma
   Pilocytic astrocytoma is the most common paediatric glioma and accounts for approximately
   85% of all cerebellar astrocytomas in children. Peak age is between birth and nine
   years old. (Over 80% of haemangioblastomas occur in adulthood.) They are associated with
   neurofibromatosis type 1 (café-au-lait spots and skeletal abnormalities).
   The most common appearance is of a cyst with an intensely enhancing mural nodule
   (arachnoid cyst should be devoid of an enhancing nodule). They occasionally calcify
   (calcification is rare in haemangioblastomas).
   They run a relatively benign clinical course and almost never recur following surgical
   excision. There is no malignant transformation to anaplastic form

Question 7

7. A neonate has an abdominal ultrasound following the finding of a palpable abdominal
   mass. The right kidney is normal. The left kidney is replaced by multiple cysts of varying
   size and shape. There is no communication between the cysts, which are separated by
   septae. Which of the following is the most likely diagnosis?
   a. Multilocular cystic renal tumour
   b. Autosomal recessive polycystic kidney disease
   c. Autosomal dominant polycystic kidney disease
   d. Multicystic dysplastic kidney
   e. Medullary sponge kidney

Answer 7

7. d. Multicystic dysplastic kidney
   These features are highly suggestive of multicystic dysplastic kidney. The condition is
   invariably fatal if bilateral, but often asymptomatic if unilateral. It is the second commonest
   cause of a palpable abdominal mass in the neonate, second only to hydronephrosis. The key
   features are that no normal renal tissue is present, the cysts do not communicate with each
   other and they are separated by septae.

Question 8

8. A three year old boy has an ultrasound and an abdominal CT scan following the
   discovery of a palpable abdominal mass. No other symptoms are present. A large
   abdominal mass measuring 9 cm in maximum cross-sectional dimensions is seen.
   Which one of the following features would favour a diagnosis of Wilms tumour rather
   than neuroblastoma?
   a. Calcification
   b. Bone metastases
   c. Lung metastases
   d. Encasement of the major vessels
   e. Displacement of the kidney

Answer 8

8. c. Lung metastases
   Lung metastases are rare in neuroblastoma and are seen in only 10% of cases, whereas they are
   seen in 85% of metastatic Wilms tumours. Wilms tumours tend to displace rather than encase
   the vessels, and intrinsic mass effect, rather than displacement of the kidney, is seen. Calcification
   is seen in 90%of neuroblastomas but only 10% ofWilms tumours. Wilms tumours are the
   most common abdominal neoplasmin children between one and eight years of age. It typically
   presents with an asymptomatic abdominal mass but pain, haematuria and fever may be found.

Question 9

9. A ten year old boy presents with severe localised pain in the distal femur with an
   associated swelling. Blood films show a leucocytosis and anaemia. At the time of diagnosis
   he has both lung and bone metastases. The most likely diagnosis is:
   a. Osteosarcoma
   b. Giant cell tumour
   c. Lymphoma
   d. Ewing’s sarcoma
   e. Clear cell sarcoma

Answer 9

9. d. Ewing’s sarcoma
   Ninety-five per cent present between 4 and 25 years of age. Sixty per cent occur in the long
   bones, mainly in the metadiaphysis and have a typical moth-eaten destructive appearance on plain film. Metastases to the lung, bone and regional lymph nodes are present in 11–30%
   of cases at the time of diagnosis.

Question 10

10. A plain film taken of a five year old boy following a fall shows a fracture of the
    distal radius. The fracture runs through the physis and the metaphysis, but the
    epiphysis is not involved. The correct classification of this fracture is:
    a. Salter Harris I
    b. Salter Harris II
    c. Salter Harris III
    d. Salter Harris IV
    e. Greenstick fracture

Answer 10

10. b. Salter Harris II
    This is the most common type of Salter Harris fracture. The Salter Harris classification is a
    widely accepted and useful classification system for describing epiphyseal plate injuries;
    these represent between 6 and 30% of all paediatric fractures. The most common site is the
    distal radius, followed by the phalanges of the hands and feet and the distal tibia.

Question 11

11. A ten year old girl falls and injures her left elbow. No bony injury is demonstrated
    on plain radiographs. On interpretation of the plain radiographs, which one of the
    following ossification centres is the least likely to be present?
    a. Trochlear
    b. Radial head
    c. Medial epicondyle
    d. Lateral epicondyle
    e. Olecranon

Answer 11

11. d. Lateral epicondyle
    The lateral epicondyle is the last of the above structures around the elbow to ossify. The
    mean age for ossification of the lateral epicondyle is ten years. The sequential order of
    ossification starting with the earliest is capitellum, radial head, medial epicondyle, trochlear,
    olecranon and finally lateral epicondyle. The relevant ages are (in years) two, five, five, nine,
    nine and ten years respectively.

Question 12

12. A four year old girl presents with persistent left upper lobe pneumonia with a fingerlike
    opacity projecting from the hilum. The most likely diagnosis is:
    a. Bronchial atresia
    b. Intralobar sequestration
    c. Staphylococcal pneumonia
    d. Congenital lobar emphysema
    e. Bronchogenic cyst

Answer 12

12. a. Bronchial atresia
    The site and features described are characteristic of bronchial atresia.

Question 13

13. A five month old baby presents with failure to thrive and respiratory distress.
    Plain radiograph demonstrates a left basal homogenous opacity devoid of air bronchograms.
    Which of the following is least likely on further imaging?
    a. Radionuclide angiography does not demonstrate perfusion in the pulmonary phase
    b. Invested in its own pleura
    c. Co-existing anomalies are common
    d. It is usually supplied by branches from the descending aorta
    e. Commonly drains into the left atrium

Answer 13

13. e. Commonly drains into the left atrium
    Extralobar sequestration is usually seen in early childhood and demonstrates all the above
    features, but the venous drainage is into the right atrium through systemic veins.

Question 14

14. A 14 year old patient with Turner syndrome presents with severe headache. Clinical
    examination confirms upper limb hypertension and a murmur. Which of the following
    signs is likely on the plain films?
    a. Boot-shaped heart
    b. Snowman sign
    c. Figure-of-three sign
    d. Egg-on-a-string sign
    e. Scimitar sign

Answer 14

14. c. Figure-of-three sign
    The above mentioned are plain radiography signs of various congenital heart diseases. The
    condition described above is coarctation of the aorta. A boot-shaped heart is a feature of
    tetralogy of Fallot. Snowman sign or figure-of-eight sign is seen in supracardiac TAPVD.
    Scimitar sign is a feature of partial anomalous pulmonary venous return, and egg-on-astring
    sign is noted in TGA.

Question 15

15. An 11 year old boy undergoes investigation for a mass in his right orbit. CT shows
    a hypodense mass located in the upper temporal quadrant. The Hounsfield units
    are positive throughout the lesion. There is no calcification and the lesion does not
    enhance. There is adjacent scalloping of the lateral orbital wall. On MRI, the lesion is hypointense on T1 and hyperintense on T2, FLAIR and diffusion-weighted imaging.
    What is the most likely diagnosis?
    a. Orbital teratoma
    b. Orbital pseudotumour
    c. Conjunctival choristoma
    d. Dermoid cyst
    e. Epidermoid cyst

Answer 15

15. e. Epidermoid cyst
    Both epidermoid and dermoid cysts appear as unenhanced, well-circumscribed, low-density
    masses. Both can cause scalloping and sclerosis and even destruction of the adjacent bone.
    Epidermoids do not calcify and do not contain fat (negative Hounsfield units). The
    presence of calcification and/or fat is characteristic of dermoid cysts.
    Dermoids and epidermoids have low signal on T1 (unless the former contains fat) and
    high signal on T2, FLAIR and diffusion-weighted imaging. Both may be found in several locations in the orbit, but most frequently superiorly and temporal. They are congenital
    cysts but many become evident in the second and third decades.
    Teratomas are evident at birth as grossly visible cystic orbital masses. They tend to affect
    girls, are unilateral and grow rapidly. Conjunctival choristomas (dermolipomas) are less
    dense than solid dermoids and contain more adipose tissue.

Question 16

16. The mother of a three week old child notices a mass in her baby’s lower neck. The child
    is otherwise well. There is a history of normal pregnancy and the child was delivered
    by forceps. Ultrasound scan reveals homogeneous enlargement of the lower third of
    the right sternocleidomastoid muscle but no focal lesion is identified. T2-weighted
    MRI shows diffuse abnormal high signal intensity over the same area. The most
    likely diagnosis is:
    a. Haematoma
    b. Branchial cleft cyst
    c. Fibromatosis colli
    d. Neuroblastoma
    e. Cystic hygroma

Answer 16

16. c. Fibromatosis colli
    This is a rare form of infantile fibromatosis that occurs solely within the sternocleidomastoid
    muscle. In the vast majority it is associated with birth trauma (e.g. forceps delivery).
    This is thought to lead to compartment syndrome, pressure necrosis and secondary fibrosis
    of the muscle. It usually locates to the lower third of the muscle, between the sternal and
    clavicular heads, and is usually unilateral.
    Ultrasound may reveal a well- or ill-defined mass or may just show homogeneous muscle
    enlargement. In approximately two-thirds of individuals, the abnormality spontaneously
    regresses by the age of two. Expected ultrasonographic appearances of a haematoma include
    a heterogeneous mass of mixed cystic and solid components.

Question 17

17. A three year old boy presents with headaches and drowsiness. Examination reveals
    papilloedema. CT brain shows hydrocephalus and a mildly hyperdense homogeneous
    mass at the trigone of the left lateral ventricle. There is intense homogeneous enhancement
    post-contrast. On MRI the lesion is slightly hyperintense on T1 and slightly
    hypointense on T2-weighted imaging relative to white matter. Gadolinium injection
    confirms an intraventricular enhancing tumour island. The most likely diagnosis is:
    a. Choroid plexus papilloma
    b. Intraventricular meningioma
    c. Ependymoma
    d. Cavernous angioma
    e. Pilocytic astrocytoma

Answer 17

17. a. Choroid plexus papilloma
    Eighty-six per cent of choroid plexus papillomas occur below the age of five years and they
    represent approximately 65% of choroid tumours. Large aggregation of choroid produces
    CSF at an abnormal rate. This CSF overproduction contributes to hydrocephalus.
    The most common location in children is the trigone of the lateral ventricle, the third
    ventricle is unusual and the fourth ventricle and cerebellopontine angle are more common
    in adults.
    The tumour shows a smooth lobulated border and small calcifications are common.
    There is intense homogeneous enhancement. Approximately 5% undergo malignant transformation
    to choroid plexus carcinoma.
    Meningiomas are the most common trigonal intraventricular mass in adulthood. They
    rarely occur under the age of 20.
    Cavernous haemangiomas tend to occur in the third to sixth decades and are located in
    the subcortical cerebrum.

Question 18

18. An eight month old girl is diagnosed with neuroblastoma following the finding of an
    abdominal mass. At CT the tumour is found to arise from the right suprarenal
    region and does not cross the midline. There are liver metastases, and bone marrow
    aspirates are positive for tumour. However, there is no evidence of skeletal metastases
    on plain films. What is the correct stage of the tumour?
    a. Stage I
    b. Stage II
    c. Stage III
    d. Stage IV
    e. Stage IVs

Answer 18

18. e. Stage IVs
    The tumour should be staged as stage IVs. This stage refers specifically to patients less than one
    year of age with no crossing of the midline and disease confined to the liver, skin and bone
    marrow without radiographically evident skeletal metastases. It confers a good prognosis.
    Stage I is tumour confined to the organ of origin, stage II includes regional spread not crossing
    the midline, stage III is extension across the midline and stage IV includes metastatic disease

Question 19

19. A two year old boy presents with failure to thrive and a left-sided abdominal mass
    is found. An ultrasound scan reveals a left-sided hydronephrosis. The right kidney
    is normal. Which one of the following is most likely to be found as the underlying
    cause?
    a. Posterior urethral valve
    b. Pelvic–ureteric junction obstruction
    c. Urethral diverticulum
    d. Ureteric calculus
    e. Ureterocoele

Answer 19

19. b. Pelvic–ureteric junction obstruction
    Hydronephrosis is a common cause of a palpable abdominal mass in children. The most
    common cause of hydronephrosis is pelvic–ureteric junction obstruction, followed by
    posterior urethral valves and ectopic ureterocoele. Pelvic–ureteric junction obstruction is usually due to a functional abnormality of the ureteric musculature and is found more
    commonly on the left than the right.

Question 20

20. A neonatal boy has a renal ultrasound performed for the investigation of urinary
    obstructive symptoms. The ultrasound shows a distended urinary bladder with bilateral
    hydronephrosis. Which one of the following is the most likely underlying
    pathology?
    a. Posterior urethral valve
    b. Neurogenic bladder
    c. Horseshoe kidney
    d. Ectopic ureterocoeles
    e. Urethral diverticulum

Answer 20

20. a. Posterior urethral valve
    Posterior urethral valve is a congenital disorder characterised by a thick mucosal fold
    located in the posterior urethra. It is the most common cause of bilateral urinary tract
    obstruction in boys. It is most commonly discovered in the neonatal period, but very
    occasionally may present into adulthood. Diagnosis is usually made with ultrasound and
    surgical treatment is indicated.

Question 21

21. In a neonatal lumbar spine film showing a ‘bone-within-bone’ appearance, which of
    the following would NOT be a plausible explanation?
    a. Osteopetrosis
    b. Normal variant
    c. Congenital syphilis
    d. Sickle cell anaemia
    e. Achondroplasia

Answer 21

21. e. Achondroplasia
    Achondroplasia does not cause a bone-within-bone appearance. This phenomenon can,
    however, be seen as a normal variant within the neonatal thoracic and lumbar spine. As well
    as the above conditions, a bone-within-bone appearance is also seen in thalassaemia,
    acromegaly, Paget’s disease, rickets, scurvy, hypothyroidism, hypoparathyroidism,
    Gaucher’s disease and post-radiation, amongst others.

Question 22

22. A six year old boy presents to A&E with pain in the right hip and knee, limitation
    of movement and a limp. Plain radiographs show flattening of the capital femoral
    epiphysis and enlargement of the medial joint space. Blood tests are normal. Which of
    the following is the most likely diagnosis?
    a. Legg–Calve–Perthes disease
    b. Transient synovitis
    c. Osteomyelitis
    d. Slipped upper femoral epiphysis
    e. Developmental dysplasia of the hip

Answer 22

22. a. Legg–Calve–Perthes disease
    These features suggest Legg–Calve–Perthes disease; this is idiopathic avascular necrosis of
    the femoral head in children. The peak age group is between four and eight years. The
    earliest visible signs on plain film include small femoral epiphysis, sclerosis of the epiphysis
    and widening of the joint space due to thickening of the cartilage. A frog-leg lateral view is
    useful and may be the only view in which some of the findings are seen.

Question 23

23. A two year old boy is brought to the A&E department with a history of falling down
    the stairs. There is some concern regarding the delay in presentation and the consistency
    of the history. Bruising is noted to various parts of the child’s body. A skeletal
    survey is performed as there is concern regarding non-accidental injury. Which of the
    following findings would be the most concerning for non-accidental injury?
    a. Salter Harris II fracture to the distal radius
    b. Spiral fracture of the tibia
    c. Scapula fracture
    d. Linear parietal skull fracture
    e. Avulsion of the medial epicondyle

Answer 23

23. c. Scapula fracture
    A scapula fracture implies a high-energy injury and would be concerning for non-accidental
    injury. Posterior rib fractures, particularly if of differing ages, are also specific for nonaccidental
    injury. Toddlers who are just beginning to mobilise independently may sustain a
    spiral fracture of the tibia, sometimes known as a ‘toddler’s fracture’. Salter Harris fractures
    are common in children and are most commonly seen at the distal radius and the phalanges
    of the hands and feet.

Question 24

24. A 12 year old girl with developmental delay undergoes a skeletal radiograph for
    assessment of bone age. Plain films of her hands show granular fragmented epiphyses,
    and bone age is calculated as 9.5 years. Which one of the following is the most likely
    diagnosis?
    a. Pseudohypoparathyroidism
    b. Hypothyroidism
    c. McCune–Albright syndrome
    d. Hyperthyroidism
    e. Acrodysostosis

Answer 24

24. b. Hypothyroidism
    Hypothyroidism causes markedly retarded skeletal maturation – often up to five or more
    standard deviations below the mean. Other common causes of delayed bone age include
    hypopituitarism, hypogonadism (Turner’s syndrome), Cushing’s disease, diabetes mellitus,
    rickets and malnutrition.
    The remainder of the conditions listed cause acceleration of skeletal maturity. McCune–
    Albright syndrome is characterised by polyostotic fibrous dysplasia and precocious puberty.

Question 25

25. A 14 year old with thalassaemia presents with mild breathlessness. The only abnormality
    on the chest radiograph is a well-rounded opacity without any air bronchograms.
    The likely location would be:
    a. Perihilar
    b. Anterior mediastinal
    c. Abutting the chest wall
    d. Paravertebral
    e. Apical

Answer 25

25. d. Paravertebral
    Extramedullary haemopoiesis can present as uni/bilateral rounded masses in the lower
    paravertebral region commonly between T8 and T12.

Question 26

26. A four year old child with a known malignancy presents with multiple pulmonary
    metastases. Which of the following is the most likely radiological description of the
    primary lesion?
    a. CT of the abdomen demonstrating a large mass in the left flank displacing the
    kidney inferiorly with stippled calcification
    b. CT of the abdomen demonstrating a large low-attenuation hepatic mass
    pre-contrast which demonstrates early and avid enhancement post-contrast
    c. CT of the abdomen demonstrating a low-attenuation hepatic mass with rim
    enhancement
    d. Plain radiograph of the right femur revealing a moth-eaten permeative lesion
    e. A well-circumscribed heterogeneous mass in the left kidney which enhances to
    a lesser degree than the kidney

Answer 26

26. e. A well-circumscribed heterogeneous mass in the left kidney which enhances to a
    lesser degree than the kidney
    Neuroblastoma (a) presents earlier and is more likely to metastasise to the liver, whilst this
    is the right age for Wilms tumour (e) to metastasise to the lung. Haemangioendothelioma
    (b) presents in early infancy with heart failure. Hepatoblastoma (c) also presents earlier and
    is less common than Wilms tumour, although it does metastasise to the lung.

Question 27

27. A neonate presents with respiratory distress a week after birth. Plain radiograph
    demonstrates a hazy opacity in the left upper zone. Follow-up radiograph a few days
    later demonstrates clearing up of the opacity noted previously and a hyperlucent
    underlying lung with evidence of a contralateral shift. Which of the following is not
    a likely cause for the findings?
    a. Bronchial dysplasia
    b. Inspissated mucous
    c. Patent ductus arteriosus
    d. Anomalous origin of the right subclavian artery
    e. Bronchial web

Answer 27

27. d. Anomalous origin of the right subclavian artery
    The features described are those of congenital lobar emphysema, which may result from all
    the above apart from anomalous origin of the right subclavian artery, which usually does
    not result in tracheobronchial indentation.

Question 28

28. A neonate presenting with respiratory distress and a scaphoid abdomen is diagnosed
    with congenital diaphragmatic hernia following imaging. Which of the following is true?
    a. Right-sided hernia is frequently fatal
    b. The anterior hernias are larger
    c. The stomach is the commonest viscera to herniate
    d. Morgagni hernia present earlier
    e. Early intrauterine diagnosis is associated with an improved prognosis

Answer 28

28. a. Right-sided hernia is frequently fatal
    Whilst congenital diaphragmatic hernias are commoner on the left, right-sided ones are
    frequently fatal. Anterior (Morgagni) hernia is usually smaller and presents in childhood,
    whilst posterior (Bochdalek) hernia is larger and presents early. Small bowel is the
    commonest viscera to herniate. Intrauterine diagnosis before 25 weeks is an indicator of
    poor outcome.

Question 29

29. A two month old child is brought to hospital as his parents have noticed he has become
    more floppy over the preceding weeks. Examination reveals marked hypotonia, head
    lag and increased head circumference (>98th percentile). CT brain shows low-density
    white matter. T2-weighted MRI demonstrates diffuse, symmetric increased signal intensity throughout the white matter. There is relative sparing of the internal and
    external capsules and also the corpus callosum. Both globus pallidi show high signal
    intensity but there is relative sparing of the putamen and caudate nucleus. Which of the
    following would fail to confirm the diagnosis?
    a. Brain biopsy
    b. Proton MR spectroscopy
    c. Quantitative urine study
    d. Fibroblast cultures
    e. Diffusion-weighted MRI

Answer 29

29. e. Diffusion-weighted MRI
    The history and MRI findings are suggestive of Canavan disease. This is an autosomal
    recessive disorder due to deficiency of the enzyme aspartoacylase. Accumulation of
    N-acetylaspartic acid (NAA) in the brain pursues and leads to leukodystrophy.
    Histology reveals soft and gelatinous white matter. Change is most prominent in the
    deeper cortex and subcortical white matter, with relative sparing of the deeper white matter
    and internal capsule.
    On T2-weighted MRI, the globus pallidus is always of high signal intensity, with frequent
    involvement of the thalamus but with relative sparing of the caudate and putamen.
    The main differential diagnosis on imaging is Alexander disease, a rare disorder which
    shows no pattern of inheritance. Both conditions are leukodystrophies with macrocrania.
    Brain biopsy can be used to differentiate.
    Diagnosis of Canavan disease is also possible with proton MR spectroscopy which shows
    a characteristic increase in the NAA peak. Levels of NAA are also abnormally high in urine
    and there will be a deficiency of aspartoacyclase in cultured skin fibroblasts. Aspartoacyclase
    is not present in plasma or blood cells. Diffusion-weighted MRI will add little to the
    information already obtained with T2-weighted imaging

Question 30

30. An 18 month old boy is investigated for hyperactivity and laughing fits. MRI demonstrates
    a lesion arising near the floor of the third ventricle, posterior to the pituitary
    infundibulum. It projects into the suprasellar cistern. The lesion is isointense to grey
    matter on T1- and T2-weighted imaging and does not enhance following gadolinium
    administration. The most likely diagnosis is:
    a. Germinoma
    b. Pituitary adenoma
    c. Hypothalamic hamartoma
    d. Rathke’s cleft cyst
    e. Langerhans’ cell histiocytosis

Answer 30

30. c. Hypothalamic hamartoma
    Hypothalamic hamartoma is not a true tumour by definition. It presents either with
    precocious puberty or with gelastic seizures (paroxysms of inappropriate emotional outbursts,
    usually laughing).
    The lesion is well defined, arising from the floor of the third ventricle/around the tuber
    cinereum of the thalamus and extending inferiorly into the suprasellar cistern or interpeduncular
    cistern. The imaging characteristics described are typical. They do not enhance

Question 31

31. A ten year old girl attends the emergency department after a head injury. You are
    requested to perform an acute CT scan of her head. According to NICE guidelines for
    head injury, which one of the following criteria alone does not warrant an acute head
    CT scan?
    a. Retrograde amnesia lasting >5 minutes
    b. Antegrade amnesia lasting >5 minutes
    c. More than one episode of vomiting
    d. CSF otorrhea
    e. Abnormal drowsiness

Answer 31

31. c. More than one episode of vomiting
    NICE head injury guidelines for children (under 16) advocate CT head imaging if there
    are three or more discrete episodes of vomiting. All of the other criteria listed are requisites
    for acute CT head scanning. CSF otorrhoea implies basal skull fracture. Other criteria
    include:
    When the head injury occurs as a result of a dangerous mechanism (high-speed road
    traffic accident either as a pedestrian, cyclist or vehicle occupant, fall from over
    three metres, high speed injury from a projectile or an object).
    Age > one year; GCS <14 on assessment in the emergency department.
    Age > one year: GCS (paediatric) <15 on assessment in the emergency department.

Question 32

32. A three year old boy presents with seizures and headaches. CT head shows a hypoattenuating
    mass lying superior to the lateral ventricles, within the frontal region.
    It displays negative Hounsfield units and peripheral calcification but does not enhance.
    There is partial agenesis of the corpus callosum. MRI of the brain demonstrates a
    pericallosal tumour which is hyperintense on T1 and less hyperintense on T2-weighted
    imaging. What is the most likely diagnosis?
    a. Dermoid tumour
    b. Lipoma
    c. Teratoma
    d. Neurocytoma
    e. Ependymoma

Answer 32

32. b. Lipoma
    This is a congenital tumour that results from abnormal differentiation of the meninx
    primitiva – that which eventually differentiates into pia, arachnoid and internal dura mater.
    They account for less than 1% of brain tumours but are associated with congenital
    abnormalities, most commonly dysgenesis of the corpus callosum to some degree. This is
    particularly likely when the lipoma is located anteriorly rather than posteriorly.
    On CT they are well-circumscribed masses with negative Hounsfield units and occasional
    calcification, and they do not enhance. Characteristically, they are T1 hyperintense and
    slightly less hyperintense on T2.
    Dermoids and teratomas can show similar characteristics, with fat and calcium content.
    Teratomas may enhance, although dermoids do not. However, the lesion is much more
    likely to be a lipoma given its position (dermoids tend to be extra-axial (spinal canal);
    teratomas are much more commonly found around the pineal region, floor of the third
    ventricle, posterior fossa and spine) and given the association with corpus callosum
    abnormalities.

Question 33

33. A neonate is found to have hypotonic abdominal wall musculature, and further
    investigations reveal bowel malrotation and cryptorchidism. Which of the following
    conditions is most likely?
    a. Prune belly syndrome
    b. Zellweger syndrome
    c. Wolman disease
    d. Meckel–Gruber syndrome
    e. Wunderlich syndrome

Answer 33

33. a. Prune belly syndrome
    Prune belly syndrome is a non-hereditary disorder occurring in males with a triad of
    abdominal wall muscular hypoplasia, bilateral cryptorchidism and distended nonobstructed
    ureters. Other associations include malrotation of the gastro-intestinal tract,
    intestinal atresia, cystic renal dysplasia, vesico–ureteric reflux, pulmonary hypoplasia and
    cardiac anomalies (including PDA, tetralogy of Fallot and VSD).

Question 34

34. A two month old boy born prematurely has a CT abdomen following macroscopic
    haematuria and a palpable abdominal mass. A large intrarenal mass is seen, which
    replaces the majority of the renal parenchyma, involves the renal sinus and does not
    display any venous extension, collecting system involvement or calcification. Which
    one of the following diagnoses is most likely?
    a. Metanephric adenoma
    b. Mesoblastic nephroma
    c. Wilms tumour
    d. Nephroblastomatosis
    e. Neuroblastoma

Answer 34

34. b. Mesoblastic nephroma
    Mesoblastic nephroma is the most likely diagnosis. This is the most common solid renal
    neoplasm in the neonate. Although definitive diagnosis with CT or ultrasound is difficult,
    certain features make the diagnosis more likely; it displays infiltrative growth without
    involvement of the vascular structures or collecting system (differentiating it from Wilms
    tumour) and only very rarely calcifies (differentiating it from neuroblastoma).

Question 35

35. A premature neonate presents with bilious vomiting in the first few days of life. A plain
    abdominal X-ray shows prominent gas-fluid levels in the duodenal bulb and in the
    gastric fundus. There is absence of gas in the remainder of the small and large bowel.
    Which one of the following diagnoses is most likely?
    a. Choledochal cyst
    b. Annular pancreas
    c. Duodenal atresia
    d. Duodenal duplication cyst
    e. Ladd bands

Answer 35

35. c. Duodenal atresia
    Duodenal atresia typically presents in the first few days of life with bilious vomiting, and is
    caused by failure of recanalisation of the duodenal lumen in the fetus. It is associated with
    Down’s syndrome, congenital heart disease and other gastro-intestinal disorders such as
    malrotation, annular pancreas and biliary atresia. The characteristic feature on abdominal
    X-ray is the double-bubble sign with dilatation of the stomach and duodenal ca

Question 36

36. A young boy presents with abdominal pain and vomiting. Ultrasound of the abdomen
    confirms ileocolic intussusception. Which one of the following features is associated
    with a good chance of successful hydrostatic reduction?
    a. Symptom history of greater than 48 hours
    b. Small bowel obstruction
    c. Presence of blood flow within the intussusceptum
    d. Passage of blood per rectum
    e. Age less than three months

Answer 36

36. c. Presence of blood flow within the intussusceptum
    The following criteria are associated with a lower rate of successful enema reduction: age
    less than three months or greater than five years, long duration of symptoms, passage of
    blood per rectum, significant dehydration, obstruction of the small intestine and visualisation
    of the dissection sign during enema therapy.

Question 37

37. A seven year old boy presents to the minor injuries unit following a minor fall five
    weeks earlier. He complains of pain around the left elbow joint and has a limited range
    of movement. Blood tests are normal. Plain film of the elbow shows a small joint
    effusion and fragmentation of the capitellar epiphysis. Which one of the following is
    the most likely diagnosis?
    a. Osteochondrosis of the capitellum (Panner’s disease)
    b. Osteomyelitis
    c. Osteochondritis dessicans
    d. Juvenile chronic arthritis
    e. Osteochondral capitellum fracture

Answer 37

37. a. Osteochondrosis of the capitellum (Panner’s disease)
    The most likely cause is osteochondritis of the capitellum. The blood supply to the
    capitellum is relatively fragile and osteochondritis usually occurs following a minor injury.
    The condition usually resolves spontaneously with no long-term complications. Osteochondritis
    dessicans tends to occur in adolescents and often produces a loose body within the
    joint causing symptoms of locking.

Question 38

38. A 13 year old girl is noted to have a curvature to her spine. Plain radiographs confirm
    the presence of a scoliosis with a convexity to the right. The most likely cause of this
    would be:
    a. Neurofibromatosis
    b. Idiopathic
    c. Segmental abnormality
    d. Osteoid osteoma
    e. Infection

Answer 38

38. b. Idiopathic
    The Scoliosis Research Society has defined scoliosis as a lateral curvature of the spine of
    greater than 10. It is idiopathic in 70% of cases. The majority of children who present with
    idiopathic scoliosis do so in adolescence. There is a strong hereditary component to the
    idiopathic form. Congenital scoliosis is usually associated with vertebral anomalies such as
    block vertebrae or butterfly vertebrae. The magnitude of the curve is measured using the
    ‘Cobb’ angle, which can be determined on an AP plain film of the spine.

Question 39

39. A 12 year old boy attends A&E after falling off his bike. He complains of pain in the
    right hand. Plain radiographs show no bony injury. However, a small well-rounded
    lesion is seen in the proximal phalanx of the index finger. This has a ground glass
    appearance and contains dystrophic calcifications. There is no cortical breakthrough or
    periosteal reaction. The most likely cause of this lesion is:
    a. Simple bone cyst
    b. Aneurysmal bone cyst
    c. Enchondroma
    d. Epidermoid inclusion cyst
    e. Fibrous dysplasia

Answer 39

39. c. Enchondroma
    The most common location of these benign lesions is the tubular bones of the wrist and
    hands, and they are usually asymptomatic and therefore diagnosed incidentally. Of the
    other lesions mentioned, ABC, simple bone cyst and fibrous dysplasia are rare in the hands.
    An epidermoid inclusion cyst is most likely to occur at the distal phalanx.

Question 40

40. A 15 year old girl referred for a chest radiograph demonstrates a large well-rounded
    mediastinal mass. CT suggests a teratoma. Which of the following is true?
    a. They are often inseparable from the thymus
    b. They are always anterior mediastinal
    c. Rim enhancement indicates malignancy
    d. A fat-fluid level is a common and specific sign
    e. Homogenous soft-tissue density precludes a diagnosis of teratoma

Answer 40

40. a. They are often inseparable from the thymus
    Mature teratoma can be seen in the posterior mediastinum and may demonstrate rim
    enhancement. A fat-fluid level is a specific sign but is uncommon. They may occasionally
    have a homogenous soft-tissue appearance and be indistinguishable from lymphoma

Question 41

41. A seven year old girl with repeated chest infections and chronic cough presents with
    another episode of acute exacerbation. She is known to have raised sodium and
    chloride in her sweat. Which of the following features is least likely on an HRCT of
    her chest?
    a. Cylindrical bronchiectasis
    b. Centrilobular emphysema
    c. Segmental/subsegmental atelectasis
    d. Branching intrabronchial soft tissue
    e. Hilar lymphadenopathy

Answer 41

41. b. Centrilobular emphysema
    All the features described are of cystic fibrosis except centrilobular emphysema. They
    usually develop paraseptal emphysema.

Question 42

42. An abdominal CT in a neonate with major congenital abnormalities demonstrates
    a large central liver and absence of spleen. Which of the following features is likely on
    chest CT?
    a. Absence of the minor fissure on the right
    b. Hyparterial bronchus on the right
    c. Presence of three lobes on the left
    d. Tubular appendages bilaterally
    e. Absence of SVC

Answer 42

42. c. Presence of three lobes on the left
    The neonate has heterotaxy with right atrial isomerism, which is associated with bilateral
    trilobed lungs, and both atrial appendages are short and broad-based. It is also usually
    associated with bilateral SVC and bilateral eparterial bronchus

Question 43

43. A teenage boy with a history of nasal speech is investigated for recurrent severe
    epistaxis. The ear, nose and throat surgeon suggests the possibility of a juvenile
    angiofibroma. Which of the following CT findings would you consider typical for this
    lesion?
    a. A highly vascular nasal mass causing widening of the pterygopalatine fissure
    b. A relatively avascular fibrous nasal mass centred over Little’s area
    c. A vascular mass centred over the pterygopalatine fossa best demonstrated on
    delayed imaging
    d. A fibrous mass extending posteriorly into the middle cranial fossa with relatively
    little bone erosion
    e. A centrally located, highly vascular mass causing extensive septal destruction

Answer 43

43. a. A highly vascular nasal mass causing widening of the pterygopalatine fissure
    Juvenile angiofibromas are the most common benign nasopharyngeal tumour. They occur
    almost exclusively in teenage males. In most cases CT allows accurate diagnosis, although
    MRI may be used pre-operatively to assess soft-tissue involvement. The tumours typically
    start in the pterygopalatine fossa and cause local bone erosion. On CT, the presence of a
    nasal mass and a widened pterygopalatine fissure is pathognomonic of the condition. The
    tumour may invade the sphenoid sinus, the middle cranial fossa (via the superior orbital
    fissure), the orbit (via the inferior orbital fissure), the infratemporal fossa, or extend
    through the sphenopalatine foramen.
    The tumour may be very fibrous but tends to be highly vascular such that it only
    enhances immediately after bolus injection. Biopsy is therefore contraindicated. Angiography
    is not required to obtain the diagnosis but may be utilised for pre-operative planning
    or during therapeutic embolisation.

Question 44

44. A nine month old presents with leukokoria. Which finding would favour a diagnosis of
    persistent hyperplastic primary vitreous (PHPV) rather than retinoblastoma (RB)?
    a. Calcification
    b. Optic nerve enlargement
    c. Retinal detachment
    d. Microphthalmia
    e. Dense vitreous on CT

Answer 44

44. d. Microphthalmia
    Primary vitreous normally involutes by the sixth fetal month, but occasionally persists and
    undergoes hyperplasia. It is the second most common cause of unilateral leukokoria behind
    retinoblastoma. It may be bilateral as a part of congenital syndromes such as Norrie disease.
    Key imaging findings are micropthalmia (small hypoplastic globe) with an enhancing
    central soft-tissue band extending from the lens (retrolental) through the vitreous body to
    the back of the orbit (i.e. following Cloquet’s canal). Calcifications are not a feature
    (cf retinoblastoma – the most common cause of orbital calcifications). Both may show a
    hyperechoic focus on ultrasound and a dense vitreous on CT.
    PHPV is associated with a small optic nerve whereas retinoblastoma may show optic
    nerve enlargement due to tumour extension and may also demonstrate macropthalmia.

Question 45

45. A six year old boy is investigated for refractory complex partial seizures. CT demonstrates
    a well-defined, hypodense lesion located in the cortex of the temporal lobe.
    There is underlying bone remodelling but no calcification. On MRI the lesion demonstrates
    high signal on T2 and predominantly low signal on T1-weighted imaging. There
    is no surrounding oedema, minimal mass effect and no contrast enhancement. The most
    likely diagnosis is:
    a. Glioblastoma multiforme
    b. Dysembryoblastic neuroepithelial tumour (DNET)
    c. Primitive neuroectodermal tumour (PNET)
    d. Cavernous haemangiomas
    e. Ependymoma

Answer 45

45. b. Dysembryoblastic neuroepithelial tumour (DNET)
    DNETs are benign tumours of neuroepithelial origin which arise from the cortical/deep
    grey matter. They are preferentially located supratentorially (temporal 62%, frontal 31%).
    CT demonstrates a hypoattenuating mass and there may be thinning and remodelling of the
    underlying inner table reflecting the slow growth of the tumour.
    On MRI they are hypointense on T1, hyperintense on T2 and small intratumoural cysts
    may be present to cause a characteristic ‘bubbly’ appearance. There is minimal mass effect
    and no associated vasogenic oedema. A third of lesions show calcification and most
    tumours do not enhance. If present, the enhancement is faint and patchy.
    Gangliogliomas and cavernous haemangiomas are other tumours which may cause
    epilepsy in children. Cavernous haemangiomas are typically dense on CT and commonly
    calcify. PNETs have a tendency for necrosis, cyst formation and calcification. They also tend
    to be hyperdense on CT due to high nuclear to cytoplasmic ratio

Question 46

46. A three year old boy is referred for a Tc-99m pertechnetate scan following recurrent
    painless gastro-intestinal bleeds. A Meckel’s diverticulum is suspected. Which one of
    the following may give a false negative result?
    a. Recent barium investigation
    b. Intussusception
    c. Urinary tract obstruction
    d. Acute appendicitis
    e. Anterior myelomeningocoele

Answer 46

46. a. Recent barium investigation
    Prior to adolescence a Tc-99m pertechnetate scan has a high pick-up rate for a Meckel’s
    diverticulum. This declines with increasing age as the test relies on the presence of ectopic
    gastric mucosa, which is less likely to be present in someone asymptomatic throughout
    childhood. A false negative result is most commonly due to insufficient mass of ectopic
    gastric mucosa within the Meckel’s diverticulum, but may also be seen with barium from
    recent investigation attenuating the gamma radiation, and dilution of intraluminal activity
    due to rapid bowel transit.

Question 47

47. At a routine 20-week obstetric ultrasound scan, polyhydramnios with multiple foci
    of scattered calcifications are found throughout the fetal abdomen in between bowel
    loops. Which one of the following is most likely to be the underlying cause?
    a. Mesenteric ischaemia
    b. Meconium peritonitis
    c. Meconium plug syndrome
    d. Necrotising enterocolitis
    e. Gastroschisis

Answer 47

47. b. Meconium peritonitis
    These features are typical of meconium peritonitis. This is a chemical peritonitis secondary
    to bowel perforation in utero. The intraperitoneal meconium characteristically calcifies
    within 24 hours of perforation. Other features seen on ultrasound include fetal ascites,
    polyhydramnios and bowel dilatation.

Question 48

48. A neonate presents with abdominal distension, vomiting and failure to pass meconium.
    A water-soluble contrast enema is performed and shows a narrow rectum with
    a cone-shaped transition zone to a dilated, more proximal bowel. Which one of the
    following is the most likely diagnosis?
    a. Colonic atresia
    b. Hirschsprung’s disease
    c. Meconium ileus
    d. Cystic fibrosis
    e. Functional immaturity of the colon

Answer 48

48. b. Hirschsprung’s disease
    These features are typical of Hirschsprung’s disease. This is caused by absence of parasympathetic
    ganglion cells in the bowel wall. Meconium ileus typically shows an empty microcolon
    on water-soluble enema and colonic atresia shows a distal microcolon with
    obstruction at the point of atresia. Functional immaturity of the colon typically shows
    microcolon distal to the splenic flexure with an abrupt transition to mildly dilated proximal
    colon.

Question 49

49. The following constellation of findings in a ten year old girl suggests which of the
    following diagnoses? Absent radius and ulna, wormian bones within the skull vault,
    hypoplasia of the distal third of the clavicle and accessory epiphyses of the distal
    phalanges.
    a. Klippel–Feil syndrome
    b. Cleidocranial dysostosis
    c. Pyknodysostosis
    d. Achondroplasia
    e. Chondrodysplasia punctata

Answer 49

49. b. Cleidocranial dysostosis
    Cleidocranial dysostosis is an autosomal dominant condition. Features include multiple
    Wormian bones, delayed ossification of midline structures, hypoplasia or absence of the
    lateral portion of the clavicle (10%), elongated metacarpals and short distal phalanges of the
    hands. Pyknodysostosis is an autosomal recessive condition which also causes clavicular
    dysplasia.

Question 50

50. A seven year old boy attends A&E following a road traffic accident in which he hit
    the kerb and came off his bike. He immediately complained of neck pain and was
    immobilised at the scene. Initial plain radiographs including a swimmer’s view fail to
    demonstrate the entire cervical spine adequately. There remains clinical concern
    regarding his cervical spine. The next step should be:
    a. Trauma oblique view
    b. Flexion/extension radiographs
    c. MRI C spine
    d. CT C spine
    e. Repeat swimmer’s view with traction on arms

Answer 50

50. c. MRI C spine
    MRI should be the next investigation in a child of this age group. A ligamentous injury is
    more likely and therefore CT of the C spine may be falsely reassuring. However, in some
    centres the availability of MRI may be limited and a CT will often be performed in the first
    instance. Flexion/extension views should not be done in the acute setting. A trauma oblique
    view is performed in some institutions instead of a swimmer’s view and may be used to
    clear the cervicothoracic junction in particular

Question 51

51. An 18 month old boy with ongoing irritability and swelling of the wrists and ankles is
    referred for a series of plain films. Initial images of his wrists show marked metaphyseal
    cupping of the distal radius and ulnar and increased thickness of the radial growth
    plate. The most likely diagnosis is:
    a. Rickets
    b. Normal variant
    c. Scurvy
    d. Hypervitaminosis D
    e. Congenital hypothyroidism

Answer 51

51. a. Rickets
    The most common cause of metaphyseal cupping is Rickets. Other features include rachitic
    rosary seen on chest radiograph, widening and fraying of the metaphyses, coarse trabeculation
    and bowing of the long bones. The most common sites to be affected are the
    metaphyses of the long bones which are under stress – ankles, knees and wrists. Cupping
    of the distal ulnar may be a normal variant but none of the other signs will be present.
    Scurvy shows a radiolucent band; hypervitaminosis D and hypothyroidism cause a radiodense
    band.

Question 52

52. A four month old infant presents with cyanosis and repeated squatting episodes.
    Following an echocardiogram, a diagnosis is made. Which of the following is unlikely
    on a plain radiograph?
    a. Boot-shaped heart
    b. Fullness in the pulmonary artery
    c. Right-sided aortic arch
    d. Pulmonary oligaemia
    e. Enlarged aorta

Answer 52

52. b. Fullness in the pulmonary artery
    All the above are features of TOF except for fullness of the pulmonary artery, there is
    usually a prominent concavity in the region of the pulmonary artery.

Question 53

53. A four year old boy presents with sudden severe right scrotal pain, nausea and
    vomiting. An ultrasound and colour Doppler examination scan are performed. Which
    of the following is true regarding a diagnosis of acute testicular torsion?
    a. Normal grey-scale appearances exclude torsion
    b. Scrotal skin thickening indicates an infection
    c. Testicular hyperaemia does not exclude torsion
    d. A hydrocoele indicates a different diagnosis
    e. Non-twisted spermatic cord excludes testicular torsion

Answer 53

53. c. Testicular hyperaemia does not exclude torsion
    An enlarged, diffusely hypoechoic avascular testis with an associated twisted cord is
    diagnostic of testicular torsion. The testicular echogenicity can be normal in the very early
    phase of torsion. A detorted testis often demonstrates hyperaemia. Scrotal skin oedema and
    hydrocoele can also be features of torsion.

Question 54

54. A ten year old boy undergoes investigation for recurring morning headaches and visual
    disturbance. On examination he is noted to be short for his age. CT head shows a
    complex, partially cystic, strongly calcified inhomogeneous suprasellar mass. On MRI
    the mass is seen to fill the third ventricle and cause cranial deviation of the fornix.
    The mass is mostly hyperintense on T1 and markedly hyperintense on T2-weighted
    imaging. The solid components enhance heterogeneously. What is the most likely
    diagnosis?
    a. Germinoma
    b. Pituitary adenoma
    c. Supratentorial primitive neuroectodermal tumour (PNET)
    d. Craniopharyngioma
    e. Chiasmatic glioma

Answer 54

54. d. Craniopharyngioma
    Craniopharyngiomas (CPs) are the most common sellar/suprasellar region mass in children.
    They are benign lesions that originate from epithelial remnants (Rathke pouch) of the
    adenohypophysis and show a bimodal age distribution with peaks at the first and second
    decades (75%) and in the fifth decade (25%). They are more common in males. If the
    tumour presses on the pituitary gland, the patient may present with features of diabetes
    insipidus. Similarly, compression on the hypothalamus may lead to growth disturbance,
    compression on the optic chiasm may cause bitemporal hemianopia, and compression of
    ventricular outflow may cause raised intracranial pressure from resulting hydrocephalus.
    Classically, CPs appear as calcified, mixed cystic and solid tumours with enhancement of
    the solid component. They may be T1-bright due to proteinaceous components. Long-term
    survival in children is good (>90%).
    Germinomas are typically non-cystic and non-calcified. PNETs frequently show haemorrhage,
    necrosis and calcification and may resemble the appearance described for CPs.
    However, they are rarely found in the suprasellar region and are much more common in the posterior fossa. Chiasmatic gliomas are usually iso/hypointense on T1 and imaging usually
    defines optic nerve involvement.

Question 55

55. A four year old girl presents with nausea, vomiting and ataxia. CT shows a hyperdense
    mass in the region of the fourth ventricle. On T2-weighted MR imaging the mass is
    predominantly hypointense and contains areas of both low and high signal intensity.
    Contrast-enhanced T1-weighted imaging demonstrates a heterogeneously enhancing
    well-delineated mass that expands the fourth ventricle and causes elevation of the
    superior medullary velum. There is a moderate amount of surrounding oedema. What
    is the most likely diagnosis?
    a. Medulloblastoma
    b. Ependymoma
    c. Pilocytic astrocytoma
    d. Metastasis
    e. Subependymoma

Answer 55

55. a. Medulloblastoma
    Medulloblastomas are highly malignant lesions that account for 30–40% of all posterior
    fossa tumours. They typically arise from the roof of the fourth ventricle and 75% of cases
    occur in the first decade of life.
    On imaging, they are typically seen as hyperdense midline vermian masses which abut
    the roof of the fourth ventricle and cause hydrocephalus. There is usually mild to moderate
    perilesional oedema. Cystic change (high signal on T2), haemorrhage and calcification (low
    signal on T2) are frequently seen.
    They are fast-growing tumours and approximately 20% of cases demonstrate CSF
    dissemination at the time of diagnosis. For this reason it is important to actively search
    for evidence of further cranial or spinal disease. Treatment is usually a combination of
    surgery and radiotherapy.
    Subependymomas typically occur in middle-aged or elderly patients. Pilocytic astrocytomas
    are typically cystic with an enhancing nodule. Metastases are generally multiple and
    occur in older patients. Ependymomas are usually hypo/isodense on CT.

Question 56

56. A four year old boy presents with a painful subgaleal mass and painful right arm.
    Radiographs reveal a well-defined ovoid, lytic lesion in the right parietal bone and a
    further well-defined defect in the left temporal bone. There is also an ill-defined
    expansile lytic lesion in the shaft of the right humerus. The humeral lesion shows
    cortical erosion. T1-weighted post-contrast MRI shows that the parietal lesion is
    associated with an intensely enhancing soft-tissue mass. What is the most likely
    diagnosis?
    a. Leukaemia
    b. Langerhans’ cell histiocytosis
    c. Neuroblastoma metastases
    d. Multifocal osteomyelitis
    e. Fibrous dysplasia

Answer 56

56. b. Langerhans’ cell histiocytosis (LCH)
    The most common location for LCH is the skull, particularly the diploic space of the
    parietal bone. Lesions are typically round or ovoid and have a bevelled edge without
    marginal sclerosis, giving a punched-out appearance. (This is due to greater involvement
    of the inner table of the skull than the outer.) There may be an associated soft-tissue mass
    overlying the lytic process which is often palpable.
    LCH commonly occurs in children and they present with painful, tender bone lesions.
    Most bone involvement is monostotic (50–75%) and when occurring in long bones
    (humerus, femur, tibia), the diaphysis is the primary site.
    The differential for multiple lytic lesions in a child include (‘FLEM MC’): Fibrous
    dysplasia; Langerhans’ cell histiocytosis/Leukaemia; Enchondromatosis; Metastatic Neuroblastoma;
    Multifocal osteomyelitis; and Cystic angiomatosis (the last two are rare).

Question 57

57. A neonate presents with jaundice, pale stools and hepatomegaly. A Tc-99m DISIDA
    scan shows good hepatic uptake at 15 minutes, but on delayed imaging at six and
    24 hours no activity can be demonstrated within the bowel. Which one of the following
    is most likely to represent the underlying cause?
    a. Congenital biliary atresia
    b. Cystic fibrosis
    c. Neonatal hepatitis
    d. Spontaneous perforation of the bile ducts
    e. Choledocoele

Answer 57

57. a. Congenital biliary atresia
    Congenital biliary atresia is the most likely diagnosis. It has a slight female preponderance
    and typically presents in the neonatal period. Ultrasound features include a large coarse
    liver with increased periportal reflectivity. Biliary dilatation is not typical. In severe neonatal
    hepatitis, the features on Tc-99m DISIDA scan can appear similar to biliary atresia with
    reduced extraction and excretion. However, the more common picture is one of reduced
    hepatic uptake.

Question 58

58. Antenatal ultrasound reveals a fetus with bowel loops seen outside the abdominal
    cavity and within the amniotic fluid. Which one of the following associated features
    would support a diagnosis of gastroschisis rather than exomphalos?
    a. Liver herniation through the defect
    b. Fetal ascites
    c. Defect situated to the right of the midline
    d. Defect involving the whole length of the anterior abdominal wall
    e. Associated cardiovascular anomalies

Answer 58

58. c. Defect situated to the right of the midline
    Gastroschisis tends to be a small defect (often less than 2.5 cm in length) which occurs to the
    right of the midline. The herniated bowel does not have a peritoneal lining and floats freely within the amniotic fluid. Features suggesting exomphalos include the presence of other
    congenital anomalies, midline defect, fetal ascites, herniation of the liver, amnioperitoneal
    membrane covering the bowel and the defect covering a large extent of the anterior
    abdominal wall.

Question 59

59. A three year old boy is seen in the outpatient department following recurrent urinary
    tract infections. Which one of the following imaging modalities would be most
    appropriate to detect the extent of renal scarring?
    a. Tc-99m DTPA scintigraphy
    b. Tc-99m DMSA scintigraphy
    c. MAG-3 renogram
    d. Micturating cystourethrography
    e. I-131 OIH scintigraphy

Answer 59

59. b. Tc-99m DMSA scintigraphy
    DMSA scan is static renal scintigraphy. There is uptake in the proximal convoluted tubules
    with 50% uptake within two hours and no significant excretion in this time. Excellent
    images of the cortex can therefore be gained, making it a good investigation for detection of
    renal scarring. DMSA and MAG-3 provide more functional information.

Question 60

60. An 18 month old child with anaemia presents with E. coli gastroenteritis, heart failure
    and acute renal failure necessitating dialysis. Blood screen also confirms thrombocytopaenia.
    Which of the following is the most likely diagnosis?
    a. Pelvic–ureteric junction obstruction
    b. Medullary sponge kidney
    c. Autosomal recessive polycystic disease
    d. Haemolytic-uraemic syndrome
    e. Medullary cystic disease

Answer 60

60. d. Haemolytic-uraemic syndrome
    Haemolytic-uraemic syndrome is the commonest cause of acute renal failure in children
    needing dialysis