Misc facts Flashcards
HIDA scan in biliary atresia
Tc-99m diosgenin (DISIDA) and mebrofenin (BRIDA) have the highest hepatic extraction rate and shortest transit time of hepatobiliary radiotracers.
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Cases of biliary atresia typically demonstrate relatively good hepatic uptake with no evidence of excretion into the bowel at 24 hours.
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Pretreatment with phenobarbital (5 mg/kg/day for 5 days) to increase biliary secretion by stimulating hepatic enzymes is frequently helpful to minimise the possibility of a false-positive study in a patient with a patent biliary system but poor excretion.
Treatment and prognosis
It is important to diagnose biliary atresia early since a Kasai portoenterostomy done within the initial two months of life has a very good prognosis.
Management options include:
Kasai portoenterostomy: the surgery involves exposing the porta hepatis (the area of the liver from which bile should drain) by radical excision of all bile duct tissue up to the liver capsule and attaching a Roux-en-Y loop of jejunum to the exposed liver capsule above the bifurcation of the portal vein creating a portoenterostomy 7
liver transplantation
Causes of aqueduct stenosis
congenital
aqueductal webs or diaphragms
gliosis
extrinsic compression
- tectal plate glioma
- pineal tumour
- posterior fossa tumour
- cerebral vascular malformation
intrinsic
- infection: meningitis/ventriculitis
- subarachnoid haemorrhage
- idiopathic (called late-onset idiopathic aqueductal stenosis)
Multiple Sclerosis
Classification
Diagnostic criteria
- relapsing-remitting (RRMS)
most common (70% of cases)
patients exhibit periodic symptoms with complete recovery (early on)
- secondary progressive (SPMS)
approximately 85% of patients with relapsing-remitting MS eventually enter a secondary progressive phase
- primary progressive (PPMS)
uncommon (10% of cases)
defined by a progressive accumulation of disability for >12 months from disease onset, which can be determined prospectively or retrospectively
patients do not have remissions, with neurological deterioration being relentless
incorporates the previously described “progressive-relapsing” phenotype
- benign multiple sclerosis
15-50% of cases
defined as patients who remain functionally active for over 15 years, and thus is only a retrospective diagnosis
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Dissemination in space
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Dissemination in space requires ≥1 T2-hyperintense lesions (≥3 mm in long axis), symptomatic and/or asymptomatic, that are characteristic of multiple sclerosis in two or more of the four following locations
periventricular (≥1 lesion, unless the patient is over the age of 50 in which case it is advised to seek a higher number of lesions)
cortical or juxtacortical (≥1 lesion)
infratentorial (≥1 lesion)
spinal cord (≥1 lesion)
Notably, T2-hyperintense lesions of the optic nerve, such as those in a patient presenting with optic neuritis, cannot be used in fulfilling the 2017 revised McDonald criteria
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Dissemination in time
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Dissemination in time can be established in one of two ways :
a new T2-hyperintense or gadolinium-enhancing lesion when compared to a previous baseline MRI scan (irrespective of timing)
simultaneous presence of a gadolinium-enhancing lesion and a non-enhancing T2-hyperintense lesion on any one MRI scan
Ga-68 DOTATATE PET/CT
Other than neuroendocrine, what other tumors may be positive:
Medullary thyroid carcinoma
Meningiomas
Small cell lung carcinoma
Pituitary adenomas.
Spinal neurenteric cyst
Location and associations:
Location
The intraspinal cysts are usually intradural extramedullary (80-90%) and ventral in location. They most commonly occur in the thoracic region (~40%).
vertebral anomalies like Klippel-Feil syndrome, hemivertebra, butterfly vertebra, scoliosis, split cord and spina bifida
Gastrinoma
Location?
Associated syndromes?
% malignant?
LOCATION
90% located in the gastrinoma triangle
The triangle is formed by joining the following three points:
1) superiorly: confluence of the cystic and common bile ducts
2) inferiorly: junction of the second and third portions of the duodenum
3) medially: junction of the neck and body of the pancreas
Most gastrinomas are sporadic, although some are seen in the setting of multiple endocrine neoplasia type I (MEN I). In general, these present in young adults 1.
Gastrinomas occur in ~0.1% of patients with peptic ulcer disease.
Due to the physiological action of gastrin (>1000 pg/mL), resulting in excessive secretion of acid into the stomach, the initial manifestation is with peptic ulcer disease (PUD) with multiple recurrent and intractable ulcers, often in unusual locations. This constellation of findings due to a gastrinoma is known as Zollinger-Ellison syndrome.
insulinoma: 10% malignant
gastrinoma: 60% malignant
glucagonoma: 80% malignant
VIPoma: 75% malignant
somatostatinoma: 75% malignant
non-functional: 85-100% malignant
Lymphoid interstitial pneumonia
Describe radiological features:
Associations
IMAGING
- subtype of interstitial lung disease
- However, most of the patients are adults with a mean age of 52-56 years. If a child presents with lymphoid interstitial pneumonia, this can be indicative of AIDS.
- in women of child-bearing age, LIP is usually associated with connective tissue disease, especially Sjögren syndrome
CT
features tend to be diffuse with mid to lower lobe predominance
thickening of bronchovascular bundles
interstitial thickening along lymph channels
small but variable-sized pulmonary nodules (can be centrilobular or subpleural, and are often ill-defined)
ground-glass changes
scattered thin-walled cysts: usually deep within the lung parenchyma, typically abut vessels (i.e. perivascular or subpleural), size range between 1-30 mm (useful for differentiation from lymphoma of the lung )
mediastinal lymphadenopathy
Sjögren syndrome: considered the most common lung pathology in these patients. Can occur in up to 25% of those with lymphoid interstitial pneumonia
AIDS: particularly if it occurs in the young
autoimmune thyroid disease
systemic lupus erythematosus (SLE)
Castleman disease
common variable immune deficiency
rheumatoid arthritis
pulmonary amyloidosis
Cystic lung disease differentiation
Lymphangioleiomyomatosis
Emphysema
Pulmonary Langerhans cell histiocytosis
Birt-Hogg-Dubé syndrome
LIP
===lymphangioleiomyomatosis (LAM)===
scattered distribution, i.e. no spared areas
absence of sub-pleural cysts along fissures
underlying TSC gene mutations occur in both TSC and
sporadic LAM (cysts develop in women during their child-bearing years)
+/- renal angiomyolipomas and other features related to either TSC or sLAM
===emphysema===
advanced emphysema can appear similar to advanced cystic lung disease in LAM
fibrosis may mimic cyst walls
emphysema distribution depends on aetiology
LAM will have typical cysts separated by normal parenchyma in the least affected areas
===lymphocytic interstitial pneumonitis (LIP)===
in women of child-bearing age, LIP is usually associated with connective tissue disease, especially Sjögren syndrome
a smaller number of lower zone predominant perivascular cysts, some with internal soft-tissue may coexist with nodules, ground-glass opacity, tree-in-bud opacities, lymphoma or amyloid deposits
lung changes may pre-date typical serological abnormalities, delaying diagnosis
===pulmonary Langerhans cell histiocytosis===
upper zone predominant and bronchocentric cavitating nodules, branching or irregular cysts
spares costophrenic and costomediastinal angles
typically a disease of young adult smokers, especially men
===Birt-Hogg-Dubé syndrome===
fewer cysts with characteristic subpleural distribution and characteristic cyst shapes
autosomal dominant inheritance:
family history of pneumothorax or renal tumours
characteristic skin lesions
folliculin gene mutation
RCC
Modic endplate changes
- Modic type 1: represents bone marrow oedema and inflammation
T1: low signal
T2: high signal
T1 C+ (Gd): enhancement
- Modic type 2: represents normal red haemopoietic bone marrow conversion into yellow fatty marrow as a result of marrow ischaemia
T1: high signal
T2: iso to high signal
- Modic type 3: represents subchondral bony sclerosis
T1: low signal
T2: low signal
Caroli disease
?choledochoal cyst
Associations
Complications
Associations
Multifocal cystic dilatation of segmental intrahepatic bile ducts. However, some series show that extrahepatic duct involvement may exist.
They are also classified as a type V choledochal cyst, according to the Todani classification.
medullary sponge kidney
autosomal recessive polycystic kidney disease (ARPKD)
autosomal dominant polycystic kidney disease (exceptionally few cases exist)
- simple type
intrahepatic stone formation
recurrent cholangitis that may lead to bacteraemia and sepsis
hepatic abscesses
- periportal fibrosis type
cirrhosis and portal hypertension
hepatomegaly
ascites
varices
- up to 100x increased risk of cholangiocarcinoma, which develops in ~10% (range 2.5–17.5%) of patients
Child-Pugh score
The Child-Pugh score is a scoring system to measure the severity of chronic liver disease inclusive of cirrhosis.
class A: 5-6 points
class B: 7-9 points
class C: 10-15 points
The score is composed from several categories:
total bilirubin, μmol/L (mg/dL)
<34: 1 point
34-50: 2 points
>50: 3 points
serum albumin, g/L
>35: 1 point
28-35: 2 points
<28: 3 points
INR
<1.7: 1 point
1.7-2.3: 2 points
>2.3: 3 points
presence of ascites
none: 1 point
mild: 2 points
moderate to severe: 3 points
presence of hepatic encephalopathy
none: 1 point
grades I-II (or suppressed with medication): 2 points
grades III-IV (or refractory): 3 points
If the patient has primary biliary cholangitis or sclerosing cholangitis then bilirubin is classified as:
<68: 1 point
68–170: 2 points
>170: 3 points
The MELD score (Model for End-stage Liver Disease) is a classification used to grade liver dysfunction in preparation for liver transplantation. The score has prognostic value in terms of three month mortality and certain complications.
The components of the score are:
serum creatinine (mg/dl): if dialysis twice in last week, then creatinine is given a value of 4 mg/dl
total bilirubin (mg/dl)
INR
> 15: may benefit from liver transplantation
UIP aetiology
UIP pattern of interstitial lung disease can be seen in idiopathic pulmonary fibrosis or secondary to underlying systemic diseases. These would include:
connective tissue disorders (CTD associated UIP): falls under the broader spectrum of connective tissue disorder interstitial lung disease (CTD-ILD)
- rheumatoid arthritis: UIP is considered to be the dominant pattern in those with rheumatoid arthritis who have concurrent interstitial lung disease
- systemic sclerosis (scleroderma): either a UIP or NSIP (more common) pattern
- polymyositis/dermatomyositis: a UIP, NSIP, or cryptogenic organising pneumonia pattern
- mixed connective tissue disease: either a UIP or NSIP pattern
asbestos-related interstitial lung disease: asbestosis
chronic hypersensitivity pneumonitis
radiation
medications/drug toxicity: amiodarone lung
ANCA associated vasculitides
Hermansky-Pudlak syndrome (very rare)
A key imaging differential on cross-sectional imaging would be:
non-specific interstitial pneumonia pattern (especially fibrotic non-specific interstitial pneumonia)
fibrotic hypersensitivity pneumonitis
hypersensitivity pneumonitis usually involves the mid and upper zones of the lung, and also the presence of centrilobular nodules and areas of air trapping are very useful hints to differentiate it from UIP
amiodarone lung fibrosis: helpful clues are the presence of hyperdense pulmonary nodules or hyperdense liver on a non-contrast CT
systemic sclerosis: presence of patulous oesophagus and correlation with hand radiographs if available can be helpful
asbestosis: bilateral pleural plaques with or without calcification or peritoneal calcification are helpful in diagnosis
combined pulmonary fibrosis and emphysema (CPFE): especially if there is added upper lobe-predominant emphysema
Bronchiectasis types
Subtypes
According to macroscopic morphology, three types have been described, which also represent a spectrum of severity
cylindrical bronchiectasis
bronchi have a uniform calibre, do not taper and have parallel walls (tram track sign and signet ring sign)
commonest form
varicose bronchiectasis
relatively uncommon
beaded appearances where dilated bronchi have interspersed sites of relative narrowing
cystic bronchiectasis
severe form with cyst-like bronchi that extend to the pleural surface
air-fluid levels are commonly present
According to one study, the relative prevalence of bronchiectatic changes were
cylindrical: ~ 47%
varicose: ~ 9.9%
cystic: ~ 45.1%
multiple types: ~ 24.3%
Ebsteins anamoly + associations
apical displacement of the septal and posterior leaflets of the tricuspid valve
as a rule of thumb: if the tricuspid septal attachment lies more than 1.5 cm “beneath” (i.e. towards the apex) than mitral septal attachment, this can be considered Ebstein anomaly (in adults, the measurement is 2 cm)
“atrialisation” of the right ventricle
tricuspid regurgitation
Association
chromosomal anomalies
trisomy 13
trisomy 21
Turner syndrome
multiple other congenital heart lesions (ASD is quite common)
conduction abnormalities leading to arrhythmia (common), e.g. Wolf-Parkinson-White syndrome
maternal lithium carbonate ingestion: possible
Choledochal cyst classification
type I: most common, accounting for 80-90% 1 (this type can present in utero)
Ia: dilatation of extrahepatic bile duct (entire)
Ib: dilatation of extrahepatic bile duct (focal segment)
Ic: dilatation of the common bile duct portion of extrahepatic bile duct
type II: true diverticulum from extrahepatic bile duct
type III: dilatation of extrahepatic bile duct within the duodenal wall (choledochocele)
type IV: next most common
IVa: cysts involving both intra and extrahepatic ducts
IVb: multiple dilatations/cysts of extrahepatic ducts only
type V: multiple dilatations/cysts of intrahepatic ducts only (Caroli disease)
type VI: dilatation of cystic duct
Ostenonecrosis eponymous names and locations
Friedrich disease is an eponymous name for osteonecrosis of the sternal end of the clavicle
Freiberg Infraction – avascular necrosis (AVN) of the head of the 2nd or 3rd metatarsal
Keinbock Disease – AVN of carpal lunate
Kohler Disease – (AKA Mueller-Weiss Syndrome) – AVN of tarsal navicular
Madelung Disease– AVN of distal radial epihysis
Osgood-Schlatter Disease – AVN of the tibial tubercle
Panner Disease – AVN of capitellum of the humerus
Perthe Disease – (Legg-Calve-Perthe Disease) – AVN of femoral head in a child; idiopathic AVN of the femoral head in adult = Chandler Disease
Scheuermann Disease – AVN of the ring epiphyses of the spine
Sindig-Larsen-Johanssen Disease – AVN of distal pole of patella
Pituitary infundibular thickening
Germinoma, lymphocytic hypophysitis and Langerhans cell histiocytosis in a child. In an adult, entities such as lymphoma, metastases, and sarcoid would be possibilities.
Hypothalamic hamartoma/tuber cinereum hamartoma is interposed between the infundibulum anteriorly and the mammillary bodies posteriorly
Lymphocytic hypophysitis
Lymphocytic hypophysitis is an uncommon non-neoplastic inflammatory condition that affects the pituitary gland. It is closely related to other inflammatory conditions in the region, namely orbital pseudotumour and Tolosa-Hunt syndrome.
Epidemiology
Lymphocytic hypophysitis is seen most frequently in women, with a F:M of ~9:1, and often in the postpartum period or the third trimester of pregnancy.
Associations
autoimmune conditions such as
autoimmune thyroiditis
pernicious anaemia
immune checkpoint inhibitors
more common with CTLA4 inhibitors (e.g. ipilimumab) than PD-1 or PD-L1 inhibitors
Clinical presentation
Clinical presentation is varied depending on the part of the pituitary affected and the size of the lesion. Lymphocytic hypophysitis can thus be classified as:
anterior pituitary: lymphocytic adenohypophysitis
most common
mimics a pituitary adenoma
endocrine hormone deficits are common, including hypopituitarism
mass effects on adjacent structures (e.g. optic chiasm)
posterior pituitary: lymphocytic infundibular neurohypophysitis
rare
diabetes insipidus
both anterior and posterior pituitary: lymphocytic infundibular panhypophysitis
Tolosa-Hunt syndrome
Tolosa-Hunt syndrome is an idiopathic inflammatory condition that involves the cavernous sinus and orbital apex and is essentially a clinical diagnosis of exclusion.
Epidemiology
The estimated incidence of Tolosa-Hunt syndrome is 1 per 1,000,000 person-years with an average age of onset at 41 years
Associations
inflammatory myofibroblastic tumour (IMT)
idiopathic hypertrophic pachymeningitis (IHP)
Clinical presentation
Clinically it refers to the presence of a painful ophthalmoplegia secondary to surrounding cavernous sinus inflammation. Tolosa-Hunt syndrome is essentially a clinical diagnosis of exclusion.
Pancreatitis classification
==fluid collections associated with interstitial oedematous pancreatitis (i.e. minimal or no necrosis)==
- acute peripancreatic fluid collections (APFC): in the first 4 weeks: non-encapsulated peripancreatic fluid collections
- pseudocysts: develop after 4 weeks; encapsulated peripancreatic or remote fluid collections
==fluid collections associated with necrotising pancreatitis==
- acute necrotic collections (ANCs): in the first 4 weeks; non-encapsulated heterogeneous non-liquefied material
- walled-off (pancreatic) necrosis (WON or WOPN): develop after 4 weeks; encapsulated heterogeneous non-liquefied material
Causes of pancreatitis
I: idiopathic
G: gallstones, genetic - cystic fibrosis
E: ethanol (alcohol)
T: trauma
S: steroids
M: mumps (and other infections)/malignancy
A: autoimmune
S: scorpion stings/spider bites
H: hyperlipidaemia/hypercalcaemia/hyperparathyroidism (metabolic disorders)
E: ERCP
D: drugs (tetracyclines, furosemide, azathioprine, thiazides and many others)
Pyriform aperture stenosis
Associations
alobar and semilobar forms of holoprosencephaly
facial haemangiomas
clinodactyly
pituitary dysfunction
central megaincisor (in 75% of cases)
Risk factors and associations for renal cell carcinoma
Risk factors
cigarette smoking
dialysis-related cystic disease
obesity
treatment with cyclophosphamide (chemotherapy agent)
hypertension
post-renal transplant
Associations
hereditary renal cell cancer syndromes including:
von Hippel-Lindau syndrome: greater tendency for bilateral renal cell carcinomas as well as a presentation at a younger age; clear cell subtype
tuberous sclerosis: renal cell carcinomas occur at a younger age
Birt-Hogg-Dubé syndrome: often bilateral; chromophobe subtype
sickle cell disease and particularly sickle cell trait: renal medullary carcinoma
Xp11.2 translocation: subtype predominantly seen in young patients, comprises a third of paediatric renal cell carcinomas
Risk factors for bladder carcinoma
TCC
cyclophosphamide (a chemotherapy agent) increases the risk of bladder transitional cell carcinoma with a dose-response pattern
aromatic amines in tobacco smoke
arylamines used in rubber and plastic manufacturing
polycyclic aromatic hydrocarbons in industrial combustion processes (such as smeltin
SCC
antecedent infection with Schistosomiasis
chronic irritation, e.g. indwelling catheter, bladder calculi
chronic infection
intravesical BCG (Bacillus Calmette-Guerin)
Disc herniation nomenclature
Central
Subarticular
Foraminal
Extra foraminal
Anterior
Trisomy ? is associated with ?dactyly, trisomy x with ?dactyly, triploidy with ?dactyly, and trisomy ? with ???.
Additional hallmark anomalies of trisomy ? are ? and ?
Trisomy 13 is associated with polydactyly, trisomy 21 with clinodactyly, triploidy with syndactyly, and trisomy 18 with a clenched hand with overlapping fingers. Additional hallmark anomalies of trisomy 13 are holoprosencephaly and cleft lip/palate.
Parinaud syndrome
Parinaud syndrome is characterised by a classic triad of findings:
upward gaze palsy, often manifesting as diplopia
pupillary light-near dissociation (pupils respond to near stimuli, but not light)
convergence-retraction nystagmus
Hepatoblastoma epidemiology
most common pediatric primary hepatic malignancy, peaking in incidence between 1-2 years of age with very rare cases occurring in the teenage population.
While the tumor commonly occurs in isolation, predisposing syndromes include Beckwith-Wiedemann syndrome, hemihypertrophy, and Gardner syndrome among others.
Hepatomegaly and/or palpable abdominal mass are the most common clinical presentations.
Alpha-fetoprotein is elevated in the majority of cases. The purposes of imaging are to suggest the diagnosis, evaluate for local or distant tumor spread, and provide preoperative planning details, including segmental extent.
Calcifications may be seen in 50% of cases.
Paediatric liver lesions
Hemangioendothelioma
A single, large congenital hepatic mass with hypervascular periphery is characteristic of a focal infantile hepatic hemangioma, sometimes referred to as a hemangioendothelioma.
Infantile hepatic hemangiomas may be single and large (often referred to as hemangioendotheliomas), multifocal, or diffuse. Depending on size and number, these lesions may be asymptomatic or result in varying degrees of heart failure (due to shunting), liver failure, hypothyroidism, or compartment syndrome. These lesions ultimately regress, similar to cutaneous infantile hemangiomas. However, symptoms may necessitate various therapies, including steroids, embolization, or transplantation. Despite a similar pattern of delayed centripetal enhancement, these lesions are distinct from adult cavernous “hemangiomas” of the liver. Kasabach-Merritt syndrome is not typically seen in these masses but is usually secondary to the rarer and distinct Kaposiform hemangioendothelioma.
Mesenchymal hamartoma
This congenital hepatic mass classically has large cystic components but may have variable degrees of enhancing stroma.
Hepatoblastoma
Hepatoblastoma is usually a solitary, well-defined, heterogeneous mass that may be multilobulated. It typically enhances less than normal liver. There are isolated reports of hepatoblastoma with peripheral enhancement and central, delayed filling. The incidence peaks at 1-2 years of age, and alpha-fetoprotein is usually elevated.
Hepatocellular carcinoma (HCC)
HCC is the most common primary pediatric hepatic malignancy beyond 5 years of age. The lesions may be hypervascular and associated with underlying liver parenchymal disease (unlike hepatoblastoma). Vascular invasion is common, and alpha-fetoprotein levels are usually elevated.
Rounded atelectasis
Rounded atelectasis occurs as a consequence of infolding of normal lung secondary to thickening of the adjacent pleura.
Key features of rounded atelectasis include opacity (usually round or ovoid in shape) adjacent to pleural thickening with conspicuous volume loss.
The comet tail sign describes the swirling of adjacent bronchovascular structures into the area of rounded atelectasis.
While rounded atelectasis is commonly described as a sequel of asbestos-related pleural disease, any cause of chronic pleural effusion or thickening, such as after cardiac or thoracic surgery, empyema, hemothorax, or pleurodesis, can lead to the development of rounded atelectasis.
Nephrogenic systemic fibrosis (NSF)
Nephrogenic systemic fibrosis (NSF) is an acquired skin disease. The vast majority of patients had prior exposure to gadolinium in the setting of advanced chronic renal disease or acute kidney injury.
At approved doses of gadolinium agents (most commonly 0.1 mmol/kg except for some liver specific and intravascular agents), NSF is of far greater concern than nephrotoxicity in renal failure patients.
Although hemodialysis performed immediately after the gadolinium-enhanced MR image seems to reduce the chance of NSF, it does not always prevent it.
