GI hepatobiliary Flashcards
T/F normal calibre of the CHD is 5mm
True
T/F bile duct variants are found in 10% of all autopsies?
F- 1-3%
Name some anatomical variants that can result in bile leaks/obstruction post op?
- Aberrant intra-hepatic ducts.
- Cystic duct entering hepatic duct.
- Duplication of cystic ducts.
- Ducts of Luschka (numerous ducts draining directly into the cystic duct).
- Congenital tracheobiliary fistula.
T/F cystic duct variants account for 40% of bile duct variants?
F- 15-25%.
T/F the most common cystic duct variant is the cystic duct insuring into the middle third of the extra-hepatic duct.
T- 75%
T/F
True
In what % of ppl does the hepatic artery arise from the common hepatic artery?
50-60%
In what % of ppl does the common hepatic artery divide into the gastroduodenal artery and either right or left hepatic arteries?
10%
T/F the hepatic artery waveform is pulsatile, High resistance and shows a rapid systolic upstroke with a continuous diastolic flow?
False- the hepatic artery waveform is pulsatile, LOW resistance and shows a rapid systolic upstroke with a continuous diastolic flow
What is the normal velocity and resistive index of the hepatic artery?
30-60cm/second
Resistive index: 0.6 +/- 0.06
T/F Portal vein flow is non-pulsatile?
True, mild resp variation
What is the normal velocity of the portal vein?
20-30cm/s.
T/F hepatic vein waveform is tri-phasic with reap and cardiac variation?
True
Acute hepatitis- raised AST, ALT and unconjugated bili?
F- Raised AST, ALT and conjugated bili
Acute hepatitis may show diffuse decreased echogenicity on US?
True
Chronic hepatitis lasts at least 6 months- name some causes?
PBC, Hep B, C, D, PSC, Wilson’s, Alpha 1
3 US features chronic hepatitis?
Increased echogenicity, coarse echo, loss of definition of portal vessels.
What % of cases of cirrhosis are secondary to C2H5?
75%
Causes of cirrhosis?
V I = hepatitis T A = PBC, PSC M = HH, Wilson's, Alpha 1 I Nutritional: severe steatosis, malnutrition C D = mtx, nitrofurantoin, isoniazid
Cirrhosis- what are the 3 morphological types?
micronodular, macro nodular, mixed
What are the 4 types of nodular lesions?
- Regenerative consisting of hepatocytes and stroma
- Cirrhotic which are regenerative nodules with surrounding fibrosis
- Dysplastic nodules which are hepatic adenomas with areas of dysplasia within them (not seen on imaging) seen in hep B/C cirrhosis.
- HCC
T/F regenerative nodules can be seen on CT if they are siderotic?
True i.e. high atten nodules without arterial enhancement and similar to liver parenchyma on portal venous phase.
What are T1/T2 signal characteristics of regenerative nodules?
T1 - high
T2 - low due to siderosis
What are T1/T2 signal characteristics of dysplastic nodules?
T1- homogeneously high
T2- very low
ENhance post IV contrast
T/F neoplastic nodules in cirrhosis show variable appearance?
True
What are charact MR findings of neoplastic nodules?
- arterial enhancement
- washout during portal-venous phase
- T2 “nodule in nodule” appearance with a high signal neoplastic nodule seen within a low signal dysplastic nodule
HH CT liver appearance?
Generalised increase in liver attenuation
What are T1/T2 liver features of HH
Low signal on both T1 and T2
T/F pancreas may be dark late in disease?
True
T/F spleen is normal in primary HH and dark in secondary HH?
True
What is the most common origin of a liver abscess?
- biliary spread
other causes: contiguous spread, trauma, portal venous
Liver abscess- most common age?
60-70
T/F left lobe most common location for liver abscess?
F- right lobe, central lesions common
T/F a single liver abscess is more common than multiple liver abscesses?
False
What organism causes amoebic liver abscess?
Entamoeba histolytica
amoebic liver abscess- most common age?
30-40
T/F amoebic liver abscess most commonly located within periphery of left lobe?
F- periphery of right lobe
T/F amoebic liver abscess- usually multiple?
F- single
T/F amoebic liver abscess- usually small
F- can be greater than 5cm
amoebic liver abscess- name 3 Xray features?
- raised right hemi-diaphragm
- right basal atelectasis
- right pleural effusion
T/F US: amoebic liver abscess- early hyperechoic
F hypo echoic, ill-defined
T/F amoebic liver abscess later becomes better defined with posterior enhancement and a thick reflective wall?
True
T/F amoebic liver abscess may be simple or multi-loculated and single or multiple?
True
Amoebic or pyogenic abscesses are likely to be homogenous or heterogenous?
Homogenous
Pyogenic or fungal abscesses are likely to be homogenous or heterogenous?
Heterogenous
Describe CT findings of amoebic abscess?
- low attenuation lesions causing mass effect.
- peripheral wall enhancement
- Simple or multi-loculated with modularity of the wall
T/F Amoebic abscesses may contain gas?
F- pyogenic abscesses do!
Describe 2 CT signs specific to pyogenic abscesses?
- Double target sign: wall enhances with surrounding low attenuation zone caused by oedematous liver tissue
- Cluster sign: several abscesses cluster together looking as if they may coalesce
Describe MRI features of liver abscess?
T1- low
T2- high
Wall enhancement post contrast
Target sign on T2WI- low T2 wall with surrounding high signal due to peri-lesional oedema
Nuc med findings of liver abscess?
- uptake of sulphur colloid on Tc99m and WBCs
T/F Gallium is taken up by both pyogenic and amoebic liver abscesses?
False just by pyogenic abscesses
What is the commonest benign liver lesion?
- haemangioma (70-80% of all liver lesions)
T/F Haemangiomas are usually peripheral and single in 50% of cases
F- single in 90%
T/F haemangiomas are associated with FNH and Osler Weber Rendu?
True
How may haemangiomas present?
- incidental
- spontaneous haemorrhage
- Kasabach Merritt syndrome: haemangioma plus thrombocytopaenia
T/F haemangiomas usually
True
What does haemangioma produce when greater than 4cm?
Giant cavernous haemangioma
Haemangiomas- where does their blood supply come from?
Hepatic artery
Hepatic haemangiomas- X-ray features?
Calcifications
Hepatic haemangiomas- US features?
Variable
- majority are hyperechoic but may be hypoechoic
- may show acoustic enhancement
- NO flow on colour Doppler?
T/F Hepatic haemangiomas- may show acoustic enhancement?
T
T/F Hepatic haemangiomas- arterial flow on Doppler?
False- NO flow
Hepatic haemangiomas- CT findings?
- well- circumscribed, low attenuation
- peripheral nodular enhancement that fills in over time on delayed images
- enhance immediately
Hepatic haemangiomas- MRI findings?
- well-defined
- T1- Low signal
- T2- high signal
- central fibrous scar
- peripheral nodular enhancement that progresses centripetally with central uniform enhancement taking approx 15mins
What is the 2nd most common benign liver lesion?
FNH
FNH- peak age?
30-50, F>M
T/F FNH is associated with hepatic haemangiomas?
True
T/F FNH more common in left lobe?
False- right lobe
T/F FNH usually
True
T/F FNH- Encapsulated and sometimes pedunculated?
False - non-encapsulated and sometimes pedunculated
T/F FNH is a central scar that contains an AVM?
True
T/F FNH relatively avascular?
F- very vascular
T/F FNH contains Kuppfer cells?
True
T/F FNH usually calcified?
False- no calcifications
FNH US features?
- hyperechoic lesion showing a homogenous mass.
- displaces vessels around it
T/F - FNH US- Hyperechoic, a central hypo echoic scar seen in 90% of cases?
False- FNH US- Hyperechoic, a central hypo echoic scar seen in 15- 20% of cases
FNH Doppler features?
- enlarged vessels within the lesion with a central artery and large peripheral draining vein.
FNH- CT findings?
- ill-defined low attenuation mass
FNH- CT findings post contrast?
- transient high signal in the portal-venous phase that leaches away in equilibrium.
FNH- spoke wheel pattern with central scar seen in what % of cases?
20-30%
Central scar seen on delayed images
FNH MRI findings?
T1- isointense with well-defined central hypo intense scar
T2- isointense with hyper intense central scar in 75% of cases
Post-gad- intense arterial enhancement that becomes less intense, central scar enhances early
Kuppfer cell-specific agents such as superoxides cause enhancement of the lesion.
FNH differential?
- fibrolamellar HCC
- adenoma
- well-differentiated HCC
- giant cavernous haemangioma
- hypervascular metastasis
- intra-hepatic cholangiocarcinoma
Hepatocellular adenoma- seen in which patients?
Females on OCP
Men on anabolic steroids
Peak age 20-40
T/F Hepatocellular adenoma- most commonly sub capsular, left lobe
most commonly sub capsular, right lobe
Hepatocellular adenoma- typically what size?
5-10cm
Hepatocellular adenoma- what do they consist of?
Hepatocytes and Kuppfer cells with fat but no portal tracts within it.
Areas of haemorrhage and necrosis within.
Hepatocellular adenoma- US features?
- heterogenous, solid
- variable echotexture
- hypoechoic rim due to compression of liver tissue around the tumour
Hepatocellular adenoma- CT features?
- well-defined rounded lesion
- may have hyper dense areas if there has been haemorrhage within
T/F Hepatocellular adenoma can’t be reliably distinguished from HCC on MRI?
True- areas of haemorrhage of differing ages result in heterogenous lesion with variable appearance on different sequences
Hepatocellular adenoma- MRI signal characteristics?
T1- bright
T2 - isointense
Hepatocellular adenoma- nuc med findings?
- photopenic lesion on sulphur colloid scintigraphy surrounded by a rim of increased uptake
- no uptake on gallium scan
HCC- peak age?
60-70 years, most com visceral malignancy
HCC causes?
Wilsons HH Alpha 1 AT Tyrosinosis Hepatitis Cirrhosis (from hep B/C 40-50% of cases) C2H5 (
T/F HCC solitary in 30% of cases?
True
T/F HCC multi-focal in 60-70% of cases?
True
HCC- diffuse in what % of cases?
5 %
HCC invades the portal vein in what % of cases?
50-60%
HCC invades the hepatic vein/IVC in what % of cases?
HCC- metastasis seen in what % of cases?
70%
HCC- what is the commonest lymphatic site for mets?
hepatoduodenal nodes
HCC- commonest sites for haematogenous spread?
lungs, adrenal glands, bones
HCC- what is the pathological progression?
regen nodule- adenomatous nodule- dysplastic nodule- small HCC
HCC US findings?
- variable echogenicity
- bg cirrhosis
- invasion to hepatic or portal veins seen on colour flow
HCC CT findings?
- heterogenous enhancing mass with focal necrosis
- calcification seen in 10%
HCC invasion features?
- arterial- portal fistulae
- peri-portal streaks of high attenuation
- dilation of portal vein and branches
- no enhancement of segment of liver that is blocked
T/F intrinsic portal vein obstruction is specific to HCC?
True
How is portal vein thrombosis differentiated from HCC?
lack of enhancement of the thrombus
HCC- MRI features?
- T2- high
- T1- variable, low signal on T1 in 30-40% of cases, high T1 signal in 40-50% of cases, isointense T1 in 10-20%
- diffusion restriction
- avid enhancement post gad
T/F high grade dysplasia and small HCCs may show a “nodule in nodule” appearance?
True- esp within sideritic nodules
Large HCC- what is the mosaic pattern?
- confluent small nodules separated by thin septa
- best seen on T2Wi
- heterogenous appearance post contrast
T/F HCC- tumour capsule present in 20% of cases? Signal of tumour capsule?
F- tumour capsule present in 60-80% of cases. Dark on both T1 and T2 W images
HCC- extra capsular extension with satellite nodules seen in what % of cases?
50-70%
HCC- what are MRI findings of vascular invasion?
- high on T1
- high on GRE T1
enhancement of tumour thrombus within the vein in arterial phase and filling defect on later phases
HCC- nuc med findings?
- sulphur colloid scans- cold spot
- avid uptake on gallium scan
T/F fibrolamellar HCC is a subtype of HCC?
True- no underlying cirrhosis or risk factors for HCC.
fibrolamellar HCC- peak age?
30-40
T/F fibrolamellar HCC- usually a solitary lobulated lesion with a central scar?
true
T/F fibrolamellar HCC- encapsulated with a pseudo capsule of compressed hepatic tissue?
true
T/F fibrolamellar HCC- central amorphous calcification seen in 30-40%?
True
Fibrolamellar HCC- regional lymphadenopathy is seen in what %? and what is the commonest site?
50-60%, porta hepatis
T/F fibrolamellar HCC- distant mets are uncommon and prognosis is good?
True
Fibrolamellar HCC- US findings?
- heterogenous, predominantly hyper echoic central scar.
Fibrolamellar HCC- CT findings?
- lobulated mass
- enhancing mass with central non-enhancing scar
- pseudocapsule
Fibrolamellar HCC- MRI findings?
T1- dark T2- bright Scar dark on T1 and T2Wi Heterogenous enhancement but no enhancement of the scar Not known to cause vasc invasion
Fatty liver CT findings?
- Areas of low attenuation with HU 10
- reversed liver-spleen density
- Hyperdense intra-hepatic vessels
- focal fatty infiltration has no mass effect
Fatty liver MRI findings?
- T1- high
- T2- dark
- in and out of phase: dark on out of phase images
T/F Liver mets- most common malignant liver lesion?
True usually from colon, pancreas, breast or lung
Liver mets- both lobes involved in what % of cases?
75%
Liver mets- lesions solitary in what percent?
10%
Liver mets- US features?
- distort anatomy
- variable echogenicity
Echogenic liver mets are usually of what origin?
GiT or GuT
Liver mets do not dem Doppler flow except …?
Carcinoid
Liver mets- CT features?
- Pre-dom low attenuation
- May demo peripheral ring enhancement
How can cystic liver mets be differentiated from benign liver cysts?
- mural nodule
- fluid-fluid levels
- septations
Name 4 exclusion criteria for resection of liver mets?
- Advanced stage of primary tumour
- > 4 mets
- Extra-hepatic mets
4.
5 causes of calcified liver mets?
Colon Renal Ovarian Malignant melanoma Gastric
5 causes of hyper vascular liver mets?
Carcinoid Renal Thyroid Melanoma Pancreatic islet cell tumours
5 causes of haemorrhagic liver mets?
Colon choriocarcinoma Breast Thyroid Melanoma
What causes Budd Chiari syndrome?
- occlusion of the venous outflow of the liver: occlusion of the hepatic vein or IVC.
- most often idiopathic
Thrombotic obstruction- What is Virchow’s triad and what are the 5 Ps?
Virchow
- problem with blood FLOW
- problem with blood CONSTITUENTS
- problem with vessel WALL
Ps
- Pregnancy
- Pill
- Polycythemia rubra vera
- Platelets (excess or abnormal)
- PNH
4 causes of non-thrombotic obstruction?
Right heart failure
Constrictive pericarditis
Right atrial tumour
IVC membranes
Budd Chiari- US features?
- hepatomegaly
- caudate hypertrophy
- GB wall thickening
- Obliteration of the hepatic vein +/or IVC
- Portal vein enlargement and change in flow dynamics
- Portosystemic anastomoses
- Prominence of the azygos and hemi-azygos systems
Budd Chiari- Doppler features?
- absence/reversal of flow in the hepatic veins with dampening of the IVC waveform
- hepatic artery resistive index > 0.7
Budd Chiari- CT features?
- Hepatomegaly and ascites
- non-homogenous liver enhancement with central area of enhancement and delayed enhancement of the periphery which may demo low attenuation
- enlarged caudate lobe which enhances floridly
- poor identification of the hepatic veins
Budd Chiari- MRI features?
- peripheral liver: low signal on T1 and bright signal on T2
- non-homogenous liver parenchyma
- variable gad enhancement
- comma-shaped intra-hepatic varicose caused by intra-hepatic collateral vessels and characteristically seen on coronal images
- reduction in calibre or absence of the hepatic veins/IVC
Budd chiari- differential diagnosis?
- cirrhosis
- hepatic veno-occlusive disease
- right heart failure
What causes hepatic veno-occlusive disease?
- radiation or chemotherapy in transplant patients
MRi features of hepatic veno-occlusive disease?
- occlusion of the small centre-lobular venues without major hepatic vein thrombosis.
US features of hepatic veno-occlusive disease?
- bi-directional flow in the portal vein without evidence of hepatic vein or IVC obstruction
- GB wall thickening
Portal vein thrombosis- occurs in what % of cases of HCC?
30%
Portal vein thrombosis- occurs in what % of cases of cirrhosis?
5-10%
9 causes of portal vein thrombosis?
- Idiopathic in neonates
- Malignancy: HCC, cholangiocarcinoma, pancreatic carcinoma, liver mets.
- Hypercoagulable states
- Trauma eg iatrogenic following introduction of umbilical vein catheter
- intra-peritoneal inflammation
- Umbilical sepsis
- Pancreatitis
- Peritonitis
- Ascending cholangitis
Portal vein thrombosis- US features?
- acute phase: echogenic material within the portal vein
- increased PV diameter
- thickened lesser omentum in acute phase
Portal vein thrombosis- CT features?
- low attenuation thrombus in the portal vein on PV phase
- decrease in attenuation of the liver
- chronic- multiple peripheral collaterals may be seen
Portal vein thrombosis- MRI features?
- GRE flow voids in the portal vein
- first 5 weeks, thrombus demonstrates high T1 and T2 signal
- then high T2 signal
What is peliosis hepatis?
- benign
- dilation of sinusoidal blood-filled spaces and within the blood-filled spaces of the organs of the reticule-endothelial system- liver, spleen, bone marrow, lymph nodes and lungs
What causes peliosis hepatic? x 5
- AIDS
- Chronic infection eg TB
- Anabolic steroids
- Chronic renal failure
- Tamoxifen
Peliosis hepatis- US features?
Multiple echogenic or hypo echoic areas
peliosis hepatis- CT features?
- enhancing round lesions within the organs
- lesions are initially hypo-attenuating but become iso-attenuating with time
Cold on PETCT
