Random_17 Flashcards
Henoch-Schonlein purpura
In Henoch-Schonlein purpura, some of the body’s small blood vessels become inflamed, which can cause bleeding in the skin, joints, abdomen and kidneys. HSP –> intussusception! (due to bowel wall bleed and thickening) - usually jejunal (as opposed to ileocecal) - usually long segments
Henoch-Schonlein purpura
Henoch-Schonlein purpura (HEN-awk SHURN-line PUR-pu-ruh)
Cholecystomy tube - you have to make sure cystic duct is patent – contrast HAS to transit all the way to the small bowel!!!
Cholecystomy tube - you have to make sure cystic duct is patent – contrast HAS to transit all the way to the small bowel!!!
After resolution of clinical symptoms and decreased output from the catheter (less than 10 cc per day), abscessogram should be performed to evaluate for residual collection prior to removal.
After resolution of clinical symptoms and decreased output from the catheter (less than 10 cc per day), abscessogram should be performed to evaluate for residual collection prior to removal.
Facial colliculus syndrome
- Facial colliculus syndrome refers to a combination of neurological signs including facial palsy and lateral gaze palsy, secondary to a lesion in the facial colliculus involving motor fibers of the facial nerve and the (adjacent) nucleus of the abducens nerve. In some cases, the adjacent fibers of the MLF are also involved, which produces a conjugate gaze palsy.
- The nucleus of the abducens nerve nucleus is located in the facial colliculus on the floor of the fourth ventricle in the mid to lower portion of the pons. Fibers of the facial nerve loop around the abducens nerve in the facial colliculus.
- The MLF is the white matter tract that is located in the posterior pons near the midline, just anterior to the fourth ventricle. It contains neural fibers that interconnect the oculomotor, trochlear, abducens, and the vestibular nuclei, and it coordinates the actions of the oculomotor and abducens nuclei.
Hemangioendotheliomas tend to
spontaneously involute without therapy over a
course of months to years. Sequential ultrasounds
are often used to follow lesions and
most often demonstrate a progressive decrease
in size and an increase in degree of calcification.
Hemangioendotheliomas tend to
spontaneously involute without therapy over a
course of months to years.
Sequential ultrasounds
are often used to follow lesions and
most often demonstrate a progressive decrease
in size and an increase in degree of calcification.
the dark signal within the spleen (S), which is normal in
neonates. The spleen does not take on the typical high T2-
signal appearance until after the white pulp develops at several
weeks of age.
the dark signal within the spleen (S), which is normal in
neonates. The spleen does not take on the typical high T2-
signal appearance until after the white pulp develops at several
weeks of age.
Mesenchymal Hamartoma of the Liver
Large, multilocular, cystic masses with thin internal septations
Traumatic pancreatic transection
Fluid (arrowhead) between the pancreas and splenic vein,
a sensitive finding of pancreatic injury.
Pseudomembranous colitis
- contrast material to insinuate between the pseudomembranes and swollen haustra – accordion sign
- Because pseudomembranous colitis involves predominantly
the mucosa and submucosa, the degree of inflammatory change in the pericolonic fat is often disproportionately subtle compared to the degree of colonic wall thickening
Acute GVHD of bowel
- donor T lymphocytes cause selected epithelial damage of recipient target organs. Histopathologically, there is extensive crypt cell necrosis and, in severe cases, diffuse destruction of the mucosa throughout both the large and
small bowel and replacement with a thin layer
of highly vascular granulation tissue. - bowel wall thickening may be mild, isolated to
the small bowel, or absent. - More characteristically, there is abnormal bowel wall enhancement in a central, mucosal location corresponding pathologically with the thin layer of vascular granulation tissue replacing the destroyed
mucosa
Immunosuppression related Lymphoproliferative disorders are lymphomalike diseases related to an uncontrolled proliferation
of cells infected by the Ebstein-Barr virus in an immunocompromised host.
PTLD - EBV-related
- spectrum of imaging findings:
- focal parenchymal mass
- diffuse LAD
- mesenteric mass
- bowel wall thickening with associated aneurysmal dilatation of small bowel lumen
- In contrast to typical non-Hodgkin lymphoma (more commonly manifests as abdominal LAD), PTLD more often associated with parenchymal organ involvement
- In solid organ transplant recipients, the distribution of disease tends to occur in the vicinity of the transplant organ.
In older cystic fibrosis patients
“distal intestinal obstruction syndrome”
“meconium ileus” equivalent
In older cystic fibrosis patients
“distal intestinal obstruction syndrome”
“meconium ileus” equivalent
When to image children following UTI?
When to image children following UTI?
- girls - after 2 UTIs
- boys - after 1 UTI
Goal of imaging children after UTI?
- identify underlying congenital anomalies
- identify vesicoureteric reflux
- identify and document renal damage
- establish baseline renal size for subsequent evaluation of renal growth
- establish prognostic factors
Imaging studies for a child with UTI?
- renal U/S
- voiding cystourethrogram - VCUG
The left and right kidneys
should normally be within 1 cm of each other.
If there is a discrepancy of more than 1 cm, an
underlying abnormality should be suspected.
The left and right kidneys should normally be within 1 cm of each other. If there is a discrepancy of more than 1 cm, an underlying abnormality should be suspected.
Techniques for voiding cystourethrogram (VCUG)
- 8F catheter.
- A precontrast scout view of the abdomen is usually
obtained to evaluate for calcifications, to document the bowel pattern so that it is not later mistaken for vesicoureteral reflux, and to document the catheter position within the bladder. - Contrast is then instilled into the bladder.
- An early filling view of the bladder should be obtained to exclude a ureterocele. A ureterocele appears as a round, well-defined filling defect on early filling views. On later full views of the bladder, a ureterocele can be compressed and obscured.
- Once the patient’s bladder is full, bilateral oblique views are obtained to visualize the regions of the ureteral vesicular junctions. These views are typically obtained with the collimators open from top to bottom, with the bladder positioned at the inferior aspect of the screen and the expected path of the ureter included on the film.
- During voiding, the male urethra is optimally imaged with the patient in the oblique projection. The female urethra is
best seen on the anteroposterior view. It is critical to obtain an image of the urethra during voiding, particularly in males. In order to ensure that a view of the urethra is obtained, an image should be obtained during urination
with the catheter in place and then a second view can be obtained after the catheter has been removed. - After the patient has completed voiding, images are obtained of the pelvis and over the kidneys, documenting the presence or absence of vesicoureteral reflux and evaluating the extent of postvoid residual contrast within
the bladder.
Classic testicular microlithiasis is defined as five or more echogenic foci per view in either or both testes,
and
limited testicular microlithiasis defined as one or more echogenic foci that do not satisfy the criteria for classic testicular microlithiasis.
Classic testicular microlithiasis is defined as five or more echogenic foci per view in either or both testes,
and
limited testicular microlithiasis defined as one or more echogenic foci that do not satisfy the criteria for classic testicular microlithiasis.
External anal sphincter - leavator ani muscle
Internal anal sphincter - circular muscle of the anal canal
External anal sphincter - leavator ani muscle
Internal anal sphincter - circular muscle of the anal canal
GI lipoma/lipomatosis
- Most common site is the colon (65–75%) followed by small bowel (20–25%), stomach (5%) and, rarely, esophagus (1–2%).
- Lipomas are the second most common benign lesion in the colon but are far less common than adenomatous polyps. Additionally, lipomas are the most common benign lesion in the small bowel.
- As lipomas are typically incidental findings, no treatment is required unless the patient is symptomatic. Lipomas may be resected endoscopically or surgically depending on location and symptoms. If the mass is larger than 2 cm, it may be symptomatic, causing abdominal pain, intussusception, or anemia due to gastrointestinal bleeding from ulceration.
GI lipoma/lipomatosis
- Most common site is the colon (65–75%) followed by small bowel (20–25%), stomach (5%) and, rarely, esophagus (1–2%).
- Lipomas are the second most common benign lesion in the colon but are far less common than adenomatous polyps. Additionally, lipomas are the most common benign lesion in the small bowel.
- As lipomas are typically incidental findings, no treatment is required unless the patient is symptomatic. Lipomas may be resected endoscopically or surgically depending on location and symptoms. If the mass is larger than 2 cm, it may be symptomatic, causing abdominal pain, intussusception, or anemia due to gastrointestinal bleeding from ulceration.
Peritoneal inclusion cyst
Peritoneal inclusion cyst
Imaging features
- Typically ovoid in shape, but can become irregularly shaped when they are large, conforming to the shape of the pelvis.
- Range in size from a couple millimeters to greater than 10 cm.
- Peritoneal inclusion cysts will always be associated with an ovary.
Ovary may lie in center of cyst, suspended by thin adhesions, like a spider in a web.
Ovary may be eccentrically located within the cyst, adherent to the cyst wall.
Ovary may lie within the cyst wall.
Adjacent ovary will be normal in appearance, though may be slightly distorted due to mass effect.
- Cysts may feature septations and contain complex fluid.
No enhancing components will be identified on contrast-enhanced CT or MRI; the adjacent normal ovary should not be confused with a mural nodule.
Low-resistance flow may be detected in septations on Doppler flow ultrasonography due to small vessels traversing the mesothelial tissue in the cyst walls.
DDx
- Paraovarian cysts - usually separate from the ovary;
- the ovary lies within the lumen or within the wall of a peritoneal inclusion cyst.
- Cystic ovarian cancer is complex with enhancing solid components and no identifiable ovary; peritoneal inclusion cysts are without enhancing components and are adjacent to normal ovaries.
- Loculated ascites develops in the most dependent portions of the pelvis and is associated with peritoneal enhancement; peritoneal inclusion cysts develop adjacent to ovaries and lack enhancement.
- Hydrosalpinx is folded and tubular in shape; peritoneal inclusion cysts are typically ovoid.
In pediatric patients in whom there is clinical difficulty in distinguishing an upper from a lower UTI, cortical scintigraphy using dimercaptosuccinic acid (DMSA) has been advocated as being the most sensitive test. In the case of pyelonephritis, this study demonstrates single or multiple areas of lack of renal uptake of the radiotracer. These areas tend to be triangular and peripheral.
In pediatric patients in whom there is clinical difficulty in distinguishing an upper from a lower UTI, cortical scintigraphy using dimercaptosuccinic acid (DMSA) has been advocated as being the most sensitive test. In the case of pyelonephritis, this study demonstrates single or multiple areas of lack of renal uptake of the radiotracer. These areas tend to be triangular and peripheral.
Renal scarring (cortical thinning)
vs
Fetal lobulation
The loss of renal cortical substance as seen by ultrasound, most commonly at one of the renal poles, is suggestive of the diagnosis.
This should not be confused with fetal lobulation (also known as an interrenicular septum, a normal variant.
In pyelonephrotic scarring, the indentations of the renal contour
tend to overlie the renal calyces, whereas in fetal lobulation, the indentations are between renal calyces.
- upper indentation: b/t calices (medullary pyramids) - fetal lobulation
- lower indentations: directly over medullary pyramids - focal scarring
EVALUATION OF PRENATALLY
DIAGNOSED HYDRONEPHROSIS
- Consists of renal US and VCUG
- When is the best time to evaluate?
The controversy revolves around the timing of the ultrasound evaluation. In neonates, there is a relative state of dehydration
that occurs after the first 24 hours of life. Reports have shown that this relative state of dehydration can lead to underestimation or nondetection of hydronephrosis by ultrasound. Therefore, it is recommended that the postnatal evaluation of prenatally diagnosed hydronephrosis be performed during the first 24 hours of life or after 1 week of age.
Vesicoureteral Reflux Grading
Most low-grade VUR resolves sponta- neously by the age of 5 to 6 years unless there is an underlying anatomic abnormality.
Vesicoureteral reflux grading
- Grade 1 reflux is confined to the ureter.
- Grade 2 reflux fills the ureter and collecting system (into the pelvocalyceal system), but there is no dilatation of the collecting system.
- Grade 3 reflux is associated with blunting of the calyces. In deciding whether a calyx is dilatated or not, I was taught that if it looks like you could pick your teeth with a calyx, it is not dilatated.
- Grade 4 reflux is iden- tified by progressive, tortuous dilatation of the renal collecting system.
- Grade 5 reflux is defined by the presence of a very tortuous dilatated ureter.
Figure example:
Right side - Grade 2
Left side - Grade 5
Most common cause of congenital urinary tract obstruction?
Ureteropelvic junction obstruction
UPJ obstruction
- most common cause - intrinsic UPJ narrowing
- other cuase - extrinsic compression secondary to anomalous vessels
- children with UPJ obstruction are predisposed to renal injury even by minor abdominal trauma (see figure), due to injury to the dilated connecting system
Multicystic dysplastic kidney (MCDK) is thought to be related to severe obstruction of the renal collecting system during fetal development.
The most common appearance of MCDK is that of a grapelike collection of variably sized cysts that do not appear to communicate
Multicystic dysplastic kidney (MCDK) is thought to be related to severe obstruction of the renal collecting system during fetal development.
The most common appearance of MCDK is that of a grapelike collection of variably sized cysts that do not appear to communicate
Primary megaureter
Primary megaureter
- ureteral equivalent of Hirschsprung disease
- distal ureter - aperistaltic and spastic
- proximal ureter - dilates due to relative obstruction
- more common in boys
- more common on the left
It is the potential of posterior urethral valves that makes obtaining an image of the urethra during voiding a vital part of every VCUG performed on boys.
It is the potential of posterior urethral valves that makes obtaining an image of the urethra during voiding a vital part of every VCUG performed on boys.
Prune belly syndrome - triad
Prune belly syndrome - triad
- hypoplasia of abdominal wall muscles (manifests as bulging flanks)
- cryptorchidism
- GU tract abnormalities
Autosomal recessive polycystic kidney disease
- infantile polycystic kidney disease
- associated with hepatic fibrosis
- presents as markedly enlarged kidneys replaced by numerous small, 1-2mm cysts - echogenic kidneys
Autosomal dominant polycystic kidney disease
- adult polycystic kidney disease
- more common
- associated with hepatic and pancreatic cysts
- associated with intracranial berry aneurysms (10%)
Most common renal tumor
- prenatal/neonate (3 months old)?
- young child (3 years old)?
- older child?
Most common renal tumor in …
- prenatal/neonate (3 months old) - mesoblastic nephroma/fetal renal hamartoma
- young child (3 years old) - nephroblastoma/Wilms tumor
- older child - RCC
Rhabdomyosarcoma
Rhabdomyosarcoma
- most common malignant sarcoma of childhood
- most common location
- pelvis and GU tract
- head and neck
Pediatric scrotal masses
- testicular
- 90% - germ cell tumors
- 10% - metastasis (leukemia, lymphoma)
- extratesticular scrotal
- embryonal rhabdomyosarcoma (arising from spermatic cord or epididymis)
Pediatric scrotal masses
- testicular
- 90% - germ cell tumors
- 10% - metastasis (leukemia, lymphoma)
- extratesticular scrotal
- embryonal rhabdomyosarcoma (arising from spermatic cord or epididymis)
Torsion of testicular appendage
Torsion of testicular appendage
- enlargement of testicular appendage (>5mm)
- periappendiceal hyperemia
- self-limited - no surgery needed
Classic MRI features are low signal intensity on T1 and low/intermediate signal intensity on T2 (due to the presence of calcium). The pattern of enhancement is variable.
Most cases of solitary amyloidoma are seen in the setting of a patient with known multiple myeloma. A primary amyloidoma is a rare phenomenon in which there is focal amyloid deposition without underlying plasma cell dyscrasia.
Classic MRI features are low signal intensity on T1 and low/intermediate signal intensity on T2 (due to the presence of calcium). The pattern of enhancement is variable.
Most cases of solitary amyloidoma are seen in the setting of a patient with known multiple myeloma. A primary amyloidoma is a rare phenomenon in which there is focal amyloid deposition without underlying plasma cell dyscrasia.
Brain lesions with restricted diffusion?
Brain lesions with restricted diffusion?
- cytotoxic edema (e.g., acute ischemia or nonhemorrhagic traumatic injury);
- purulent fluid collections (abscess)
- epidermoid cysts;
- hypercellular tumors (e.g., medulloblastoma and lymphoma)
- helpful in differentiating among posterior fossa
tumors. The hypercellular medulloblastoma has
restricted diffusion, whereas ependymoma and
astrocytoma typically do not.
- helpful in differentiating among posterior fossa
DTI (diffusion tensor imaging) and tractography can be used to evaluate myelination. Increased myelination increases
anisotrophy. Therefore, in normal infants, anisotrophy
increases with age. Most disease states
that affect white matter decrease anisotrophy.
DTI and tractography can be used to evaluate
myelination. Increased myelination increases
anisotrophy. Therefore, in normal infants, anisotrophy
increases with age. Most disease states
that affect white matter decrease anisotrophy.
Brachium pontis = what structure?
Brachium pontis
=
Middle cerebellar peduncles
Distal tib-fib syndesmostic injury (high ankle sprain)
- Distal tibiofibular syndesmotic injuries, also known as “high ankle sprains,” are less common than sprains involving the lateral collateral ligament complex (esp. injury to the anterior talofibular ligament) but make up a significant minority of cases.
- It is an important entity to recognize as athletes sustaining this type of injury generally require twice as long to return to their previous level of competition compared to ankle sprains of similar severity that do not involve the syndesmosis.
- Distal tibiofibular syndesmotic injuries involve the inferior tibiofibular joint, which is made up of three main syndesmotic ligaments:
- the anterior-inferior tibiofibular ligament
- the posterior-inferior tibiofibular ligament
- the interosseous ligament
- s
everal also believe there is a fourth ligament called the inferior transverse tibiofibular ligament that is a part of the syndesmosis.
- MRI is highly sensitive and specific for diagnosing syndesmotic injuries.
- On T1-weighted images, one may see intermediate signal and blurring of the syndesmotic ligaments.
- On T2-weighted images, one may observe ligament thickening, intraligamentous hyperintensity (edema), contour irregularity, ligament discontinuity, or interosseous membrane linear hyperintensity. Fluid can also be seen extending cephalad from the joint and into the syndesmosis.
Grade IV germinal matrix hemorrhage.
On coronal ultrasound, there is a large echogenic mass in the
region of the right germinal matrix and increased echogenicity
extending into the adjacent white matter.
Periventricular Leukomalacia
- PVL - Perinatal partial asphyxia can result in damage to the periventricular white matter, the watershed zone of the premature infant.
- It most commonly affects the white matter adjacent to the atria* and the *frontal horns of the lateral ventricles.
- Neurologic sequelae: movement disorders, seizures, and spasticity.
- US findings - increased heterogeneous echogenicity is seen within the periventricular white matter. In severe cases, there may be
cystic necrosis and development of periventricular cysts. With time, there is often volume loss of the involved white matter.
Figure: PVL
Figure:
A repeat ultrasound 20 days later shows development of cystic necrosis in the bilateral frontal white matter (arrows), consistent with cystic periventricular leukomalacia.
Benign macrocrania in a 3-month-old with a large
head. The image from coronal ultrasound shows prominent
extraaxial spaces (E) and prominence of the lateral ventricles
(V). In most infants, the lateral ventricles are slitlike.
Benign macrocrania
- Dx of exclusion
- only applies to kids from 6 months to 2 years old
- US findings
- large head circumference
- prominent ventricles
- extraaxial spaces
How low does the cerebellar tonsils need to be to qualify as
Chiari 1 malformation?
5mm below foramen magnum
Complications of Chiari 1 malformation?
Hydrocephalus
Hydrosyringomyelia
Chiari malformations type 2 are almost always
associated with myelomeningoceles.
Conversely,
almost all patients with myelomeningoceles have
Chiari type 2 malformations.
Associated imaging findings of Chiari 2 malformation:
- a kinked appearance of the medulla
- colpocephaly (disproportionate enlargement of the posterior body of the lateral ventricles)
- fenestration of the falx associated with interdigitation of gyri across the midline
- enlargement of the massa intermedia
- inferior pointing of the lateral ventricles
- tectal beaking (a pointed appearance of the quadrigeminal plate
- hydrocephalus
Classification of CPAM
Classification of CPAM
- Type 1 CPAM - macrocystic - >2cm
- cannot be differentiated from Type 1 pleuropulmonary blastoma (PPB)
- Type 2 CPAM - 5mm-2cm
- Type 3 CPAM - microcystic < 5mm
Subtypes of bicornuate uterus
- bicornuate bicollis - 2 cervical canals
- bicornuate unicollis - 1 cervical canal
Compared to uterus didelphys = 2 vaginas
Figure: bicornuate unicollis
Subtypes of bicornuate uterus
- bicornuate bicollis - 2 cervical canals
- bicornuate unicollis - 1 cervical canal
Compared to uterus didelphys = 2 vagina
Figure: bicornuate bicollis
Normal esophageal impressions on fluoro
Normal esophageal impressions on fluoro
- A = aortic arch
- B = left mainstem bronchus
- C = left atrium
Haglund’s deformity
aka “Pump bumps”
Triad of:
- retro-Achilles bursitis
- retro-calcaneal bursitis
- thickening of distal Achilles tendon (partially torn Achilles tendon)
Grey matter heterotopias
- subependymal or subcortical
- nodular or band
Grey matter heterotopias
- subependymal or subcortical
- nodular or band
Schizencephaly
- a cleft in the cerebral hemisphere lined with gray matter
- presence of gray matter lining the entire cleft is the Dx feature
- separating schizencephaly from other causes of clefts (porencephaly - lined by both gray and white matter)
- extending from lateral ventricle to brain surface
- open-lipped vs closed-liped
- usually associated with agenesis of corpus callosum
Lissencephaly
- arrest of migration of neurons, resulting in:
- total failure of development of sulci and gyri = agryia
- development of abnormally broad and flat gyri with abnormally shallow sulci = pachygyria
Figure: agyria
Polymicrogyria
- small, disorganized gyri
- associated with other migrational abnormalities
- controversies as to whether polymicrogyria is a d/o of migration or a cortical dysplasia?
Figure: pachygyria
Vein of Galen malformation
- aka Vein of Galen aneurysm
- an AVF/AVM connecting one or more cerebral arteries and the vein of Galen
- in the posterior aspect of the 3rd ventricle
- clinical - high out put heart failure, cardiomegaly, and widened superior mediastinum due to vascular enlargement supplying the head
- imaging - vascular mass on Doppler and MR; associated hydrocephalus; associated cortical volume loss and edema
- death if no treatment
- Rx - arterial embolization
Porencephalic cyst
vs
Encephalomalacia
- Porencephalic cyst
- insult before the end of 2nd trimester
- parenchymal injury does NOT reesult in glial scar formation
- focal injury –> fluid-filled cystic space
- when communicating with ventricles –> porencephalic cyst
- Encephalomalacia
- insult occurs in 3rd trimester
- parenchymal injury –> glial scar formation –> encephalomalacia
- T2 hyper areas with multiple sepatations
Hydrancephaly
Hydranencephaly is the destruction of the majority of the cerebral hemispheres secondary to a massive ischemic event thought to be related to bilateral internal carotid artery occlusion.
The occipital lobes, inferior temporal lobes, thalami, brainstem, and cerebellum are typically intact.
The presence of the falx cerebri and the separation of the thalami seen in hydranencephaly help to differentiate this from holoprosencephaly.
It is sometimes impossible to differentiate hydranencephaly from severe hydrocephalus (with cortical mantle).
Most common lesions (affecting 95% of NF-1 pts) in NF-1?
NF-1 spots
- T2 hyperintense lesions in
- globus pallidus
- cerebellum
- brainstem
- internal capsule
- splenium
- thalami
- arise at 3 y/o
- increase in size until 12 y/o
- regress after
Lesions associated with NF-1
Lesions associated with NF-1
- NF-1 bright spots
- cerebral astrocytoma
- vascular dysplasia - moyamoya, cerebral aneurysms
- dural ectasia
- sphenoid wing dysplasia
- plexiform neurofibroma
- locally aggressive masses
- histologically more disorganized than typical neurofibromas
- scalp and orbits
- spinal manifestations
- scoliosis
- lateral meningoceles
- dural ectasia
- posterior vertebral scalloping - due to dural ectasia or neurofibromas
- pseudoarthrosis after long bone fractures
Figures:
- Plexiform neurofibromas in NF-1
- Note lower signal, rounded areas within the masses. These are typical for plexiform neurofibromas (collagen fiber)
*
Tuberous sclerosis
cortical tuber
vs
giant cell astrocytoma
Cortical tuber
- calcify as patients get older
- usually do not enhance
- but enhancement does not indicative of malignancy
GIant cell astrocytoma
- occurs near foramen of Monroe
- frequently leads to hydrocephalus
Sturge-Weber Syndrome
aka Encephalotrigeminal Angiomatosis
- low-flow vascular malformation
- altered flow –> chronic ischemic injury to the affected brain
- port wine stain in the trigeminal nerve distribution
- cortical hemiatrophy
- cortical calcification
- leptomeningeal enhancement
- ipsilateral choroid plexus hypertrophy and enhancement
Figure: Asymmetric, increased deep medullary veins
Normal myelination sequence
- central –> peripheral
- caudal –> cranial
Normal myelination sequence
- term birth : dorsal brainstem, cerebellum (dentate nucleus), lentiform nucleus, ventrolateral thalami, posterior limb of the internal capsule, optic tract, perirolandic regions
- 2 months : anterior limb of the internal capsule
- 3 months : splenium of the corpus callosum
- 6 months : genu and rostrum of the corpus callosum
- 18-24 months : adult pattern myelination complete
Development of corpus callosum
The development of the corpus callosum occurs between the 12th and 16-20th weeks of gestation.
It begins with the genu and then continues posteriorly along the body to the splenium.
The rostrum is the last part to be formed.
Most common TORCH infection
Cytomegalovirus
- CMV infection is the most common TORCH infection
- periventricular calcifications
- vs Toxoplasmosis –> in Toxo parenchymal calcifications are more variable in location
- migrational abnormalities (cortical dysplasia)
- cerebellar hypoplasia
Herpes simplex-1 virus in peds
- if due to reactivation and migration of a latent infection via trigeminal nerve - affects one or both temporal lobes
- if acquired during birth - any portion of the brain can be affected
Herpes simplex-1 virus
- if due to reactivation and migration of a latent infection via trigeminal nerve - affects one or both temporal lobes
- if acquired during birth - any portion of the brain can be affected
Most common type of posterior fossa tumor in peds?
Cerebellar pilocytic astrocytoma
- arises from cerebellar vermis or cerebellar hemispheres
- 4th ventricle is anterior displaced by the mass
- margin b/t the mass and the roof of the 4th ventricle is well defined
- usually do NOT demonstrate calcification or hemorrhage
Cerebellar astrocytoma
- Figure 1 - large heterogeneous T1 hypointense mass arising from cerebellar vermis. Note anterior displacement of the 4th ventricle. Dilatation of 3rd ventricle secdonary to obsructive hydrocephalus.
- Figure 2 - post contrast T1. Anterior displacement of 4th ventricle. Dilatation of temporal horns - obstructive hydrocephalus.
Second most common posterior fossa tumor in peds?
Medulloblastoma
- a type of PNET (priminitive neuroendocrine tumor)
- arises from grandular layer of the inferior medullary velum of the vermis*, i.e., the *roof of the 4th ventricle
- occupies the 4th ventricle
- board b/t the mass and the vermis is poorly defined
- CT - hyperdense
- MR - more homoregenous than cerebellar astrocytomas and ependymomas; restricted diffusion due to hyperceullarity
- CSF seeding is common
Brainstem glioma
- most commonly astrocytomas of moderate aggressiveness
- occur most commonly in the pons
- growth pattern
- circumferential enlargment of brainstem
- exophyic growth pattern
- MR - T2 hyper, enhancement is rare; 10% have cystic component
Brainstem glioma
Note the posterior displacement of 4th ventricle
Ependymoma
- arises from ciliated ependymal cells that line the ventricles, i.e., floor of the 4th ventricle
- 2/3 occur in the 4th ventricle
- tend to have a braod connection with the floor of the 4th ventricle (as opposed to roof involvement of the medulloblastoma)
- fill and grow out of the 4th ventricle via the foramina into cisterna magana and spinal canal
- Imaging - heterogeneous, heterogenous enhancement; calcification and hemorrhage common (70%)
Where do choroid plexus tumors most commonly occur?
Lateral ventricles
- most chroid plexus tumors are benign and slow growing
- but… there are malignant choroid plexus sarcomas
- markedly vascular
- marked enhancement
Common childhood tumors arising in the region of 3rd ventricle
- optic glioma
- hypothalamic glioma
- craniopharyngioma
- germ cell tumor
- pineal region tumors
Common childhood tumors arising in the region of 3rd ventricle
- optic glioma
- hypothalamic glioma
- craniopharyngioma
- germ cell tumor
- pineal region tumors
Gell cell tumors in the suprasellar region/pineal gland/hypothalamus
- germinoma
- teratoma
- embryonal carcinoma
- choriocarcinoma
Pineal tumors
- benign - pineocytoma
- malignant - pineoblastoma (PNET, highly malignant)
- almost always associated with hydrocephalus
Craniopharyngioma
- arises from squamous epithelial cells within the tract of the craniopharyngeal duct
- 7% of all pediatric intracranial tumors
- both intrasellar and suprasellar components
- 80% have calcifications
- hyperintense cystic components - proteinaceous and cholesterol laden fluid
Types of intracranial injury that should increase the degree of suspicion for child abuse
- interhemispheric subdural hematoma (caused by shaking)
- combination of traumatic injury and anoxic-ischemic injury
- traumatic SDH and SAH
- diffuse edema
- subdural hemorrahges of varying ages
Types of intracranial injury that should increase the degree of suspicion for child abuse
- interhemispheric subdural hematoma (caused by shaking
- combination of traumatic injury and anoxic-ischemic injury
- traumatic SDH and SAH
- diffuse edema
- subdural hemorrahges of varying ages
Craniosynostosis
- sagittal suture synostosis - dolichocephaly
- coronal suture synostosis - brachycephaly
- metopic suture synostosis - trigonocephaly
- synostosis of all sutures - clover leaf skull
- bulging in the squamosal areas and bregma
- thanatophoric dwarfism
Imaging findings of craniosynostosis
- bony bridging
- perisutural sclerosis
- narrowing of the involved suture
Where is bregma?
The bregma is the anatomical point on the skull at which the coronal suture is intersected perpendicularly by the sagittal suture.
Lacunar skull
- defect in the mesenchymal formation of the skull
- multiple oval lucencies that occur secondary to the thinning of the inner table of the skull
- ALWAYS associated with myelomeningoceles
- only < 3 months old; typically resolve by 6 months of age
Orbital cellulitis spectrum
Figure: Pre- and postseptal cellulitis. Axial, contrastenhanced CT shows marked asymmetric thickening of the left preseptal soft tissues (arrowheads). A line drawn through the anterior bony confines of the orbit defines tissue as pre- and postseptal. There is abnormal extraconal soft tissue (arrows) between the medial rectus muscle (R) and the bony wall of the orbit, displacing the medial rectus muscle. There is no evidence of drainable abscess. There is ethmoid sinus opacification bilaterally.
Orbital Cellulitis Spectrum
- preseptal
- postseptal
- extraconal
- subperiosteal
- almost all cases of post-septal cellulitis are associated with ethmoid sinus disease
Retinoblastomas typically present as CALCIFIED intraocular masses
Patients with retinoblastoma are also predisposed to what secondary tumor?
Patients with retinoblastoma are also predisposed to
secondary osteosarcoma from radiation therapy
DDx for pediatric orbital masses (extra-ocular)
DDx for pediatric orbital masses (extra-ocular)
- vascular
- hemangioma
- lymphatic/venous malformation
- inflammatory/infectious
- orbital cellulitis/abscess
- orbital pseudotumor
- neoplastic
- optic nerve glioma
- orbital rhabdomyosarcoma
- lymphoma/leukemia
- metastatic neuroblastoma
- retinoblastoma
- Langerhans cell histiocytosis
- congenital
- traumatic
- hematoma
Most common cause of pediatric neck masses?
Suppurative lymphadenitis
Most common branchial cleft cyst?
2nd branchial cleft cyst is most common
Occurs at the angle of the mandible
DDx for midline neck cystic lesions in children
thyroglossal duct cyst
dermoid/epidermoid
DDx for malignant neck masses in children
DDx for malignant neck masses in children
- preschool children - rhabdomyosarcoma
- older children - lymphoma
Congenital vertebral anomalies
butterfly vertebra**
hemivertebra
block vertebra
Congenital vertebral anomalies
- butterfly vertebra - lack of fusion of the 2 cartilaginous centers of the vertebral bodies resulting in a cleft in the sagittal plane
- hemivertebra - failure of formation of one of the lateral cartilaginous centers
- block vertebra - failure of separation of 2 or more adjacent vetebral bodies
Klippel-Feil syndrome
Klippel-Feil syndrome
- fused cervical vertebral bodies
- low posterior hairline
- short webbed neck
- GU anomalies
- congenital heart diesase
- Sprengel deformity - 25% of patients w/ Klippel-Feil syndrome
- high riding scapula
- bridging omovertebral bone
ALL patients with myelomeningoceles
(but not meningoceles) have associated
Chiari II malformations and 90% have hydrocephalus.
ALL patients with myelomeningoceles
(but not meningoceles) have associated
Chiari II malformations and 90% have hydrocephalus.
Tethered cord syndrome
Tethered cord syndrome
- tip of conus medullaris is low-lying (below L2/3 level) - normally above inferior margin of L2
- may occur as a primary problem or in association with other components of spinal dysraphism, e.g., lipomyelomeningocele, hemangioma, or a dermal tract
- short and thick filum (>2mm)
- on real time imaging - cord and nerve roots are not free floating
Common types of spinal dysraphism
Common types of spinal dysraphism
- open spinal dysraphism
- myelomeningocele
- myelocele
- closed (occult) spinal dysraphism
- lipomyelomeningocele (most common)
- dermal sinus tract
- tethered cord syndrome
Normal infant spinal ultrasound.
Midline sagittal image shows tip of conus medullaris to be located at the level of L2, which is normal position. The cord is shown as a hypoechoic structure, and the surrounding nerve roots are more echogenic.
Note that the cord and nerve roots lay anteriorly, with gravity.
On real-time ultrasound in a normal patient, the cord and nerve roots float freely in the CSF and show motion.
Tethered cord with associated hemangioma.
Sagittal ultrasound shows the tip of the conus medullaris to lie
abnormally low, at the level of L4. The cord and nerve roots appear to be taut (posteriorly tethered) and in a straight line and do not fall anteriorly with gravity. No motion was seen in real time.
In infants and young children, the majority of cervical spine injuries involve the superior cervical spine, as opposed to the lower cervical spine injuries seen in adults.
In infants and young children, the majority of cervical spine injuries involve the superior cervical spine, as opposed to the lower cervical spine injuries seen in adults.
‘‘hangman fracture’’
a fracture through the posterior arch of C2
‘‘hangman fracture’’
a fracture through the posterior arch of C2
Pseudosubluxation
In normal children, there may be a slightly anterior position of C2
in relation to C3. However, in contrast to ligamentous injury, with pseudosubluxation the posterior cervical line (a line drawn along
the anterior aspect of the posterior processes) remains straight. Pseudosubluxation may also be seen at the C3 to C4 level.
Pseudosubluxation of C2 onto C3.
Radiograph shows that the posterior aspect of C2 vertebral body is slightly more anteriorly positioned than is that of C3. However, the posterior cervical line shows that the posterior elements of C2 are not more anterior than the posterior elements of C3, consistent with pseudosubluxation rather than true injury.
Cortical desmoid
aka cortical irregularity syndrome
- posteromedial aspect of the distal femoral metaphysis
- chronic avulsion at the insertion of the adductor magnus muscle
- can be associated with pain
- may have associated lucency on frontal radiographs
- often bilateral - confirmation of their benign nature can be made by demosntrating a similar lesion on the contralateral side
- MR - characteristic scooplike defect with an irregular but intact cortex; no associated soft tissue mass; and sometimes a subtle contralateral lesion
Benign cortical defect
vs
Non-ossifying fibroma
The term nonossifying fibroma is typically
reserved for larger lesions.
> 2cm
While fibrous cortical defect < 2cm
Periosteal reaction can be expected to be
radiographically present 7 to 10 days after injuries
in children.
Periosteal reaction can be expected to be
radiographically present 7 to 10 days after injuries
in children.
Types of pediatric fractures
- bowing fracture
- buckling / torus fracture - a buckling of the cortex on the
concave margin of the bowing (torus fracture) - greenstick fracture - incomplete fracture along the cortex of the convex margin of the bowing
Types of pediatric fractures
- bowing fracture
- buckling / torus fracture - a buckling of the cortex on the
- concave margin of the bowing (torus fracture)
- greenstick fracture - incomplete fracture along the cortex of the convex margin of the bowing
Nonossifying fibroma visualized incidentally in a 13-year-old child with knee pain.
Radiograph shows welldefined lesion with sclerotic borders consistent with nonossifying fibroma (>2cm).
The cause of pain is identified as Osgood-Schlatter disease. Note fragmentation of tibial tubercle and enlargement and indistinctness of distal patellar tendon.
Most common type of Salter-Harris fracture?
Type 2 (75%)
extending tinto metaphysis but not epiphysis
Salter-Harris type 1
- Tend to occur in children younger than 5 years of age.
- On radiography, the epiphysis may appear to be displaced in comparison to the metaphysis.
- However, type 1 fractures often reduce prior to the radiograph’s being obtained, and the only imaging finding will be soft tissue swelling adjacent to the physis.
