Mirizzi syndrome
Common bile duct narrowing and fibrosis due to chronic gallstone diseaseStone usually impacted in gall bladder neck, cystic duct or cystic duct remnantFistula can develop between gall bladder or cystic duct and common duct, stone may partially or totally pass into common ductStricture commonly in upper and middle common ductDifficult to distinguish obstruction and thickening…
Primary sclerosing cholangitis
70% patients have history of inflammatory bowel disease – ulcerative colitisMultiple segments of stricture involving intra- and/or extra-hepatic ductsBile duct wall thickening at sites of structuring Small diverticula-like outpouchingsCholangiocarcinoma in 10% cases Imaging Cholangiography: multifocal strictures, areas of distension, pruning of ducts, areas of ductal isolationCT-IVC and MRCP: thickened biliary epithelium shows post contrast enhancement. Areas of…
Angiosarcoma (spleen)
Rare, poor prognosisMultiple nodules of varying sizeSolitary solid mass with cystic components, variable enhancement Well-defined hemorrhagic nodulesDiffuse spleen involvement Imaging CT: hypodense on plain with areas of increased attenuation due to hemorrhage. Enhancement similar to hemangioma (liver) and often not diagnosed without metastases. MR: nodular masses with hypo intense T1 and T2 margins (hemorrhagic nodules). T1 signal…
Portal hypertension
Normal pressure difference between wedged hepatic vein and IVC = 4-8 mm HgHigher pressures suggest portal hypertensionAscitesDistended mesenteric veinsDistended walls of gall bladderStomach and small bowel are edematousSplenomegaly not always presentPortal vein diameter > 15 mm suggests hypertension but a normal diameter does not rule out hypertensionPorto-systemic collaterals suggest portal venous hypertension. Common sites: splenogastric,…
Epithelioid hemangioendothelioma
Tumor of vascular originAdult womenConsists of epithelioid endothelial cellsOccasionally contains punctate calcificationMultiple peripheral nodules that coalesce, cause capsular retraction, with compensatory hypertrophy of uninvolved liver segments Can cause hepatic vein occlusion Imaging CT: multiple peripheral heterogeneous areas of low attenuation. Enhancement of rim of nodules with low attenuation halo outside ring of enhancement US: solid lesions with…
Fibrolamellar carcinoma (liver)
5-35 years age Arise spontaneouslySolitary, lobulated, well-defined tumor with central scarPunctuate calcification within scar in >50% casesContains fibrotic lamellae and numerous eosinophilic hepatocytesResection when possible5-year survival 60% Imaging CT: well-defined lobulated, low attenuation mass with even lower attenuation central scar with radial linear components and punctate calcification. Shows non-specific enhancement and delayed enhancement of scar (similar…
Focal fat (liver)
Regional or focalCauses confusion if there is any underlying massCommon sites: either side of falciform ligament, around gall bladder fossa, posterior aspect of segment IVVariations in local blood supply and venous drainage responsible for difference in fat distribution Imaging Unenhanced US and CT: angular margins, geographic appearance. Lack of mass effect, preservation of vascular architectureWhen…
Hemangioma (liver)
Commonest benign hepatic tumor 4-20% post-mortem prevalenceVascular channels of varying size, lined with endothelium, has intervening fibrous tissueAsymptomatic incidental findings Lesions 2-4 cm in size show typical imaging findings Imaging US: well defined, lobular, homogeneous, increased echo reflectivity. No doppler flow due to slow flowMRI: most sensitive and specific. Extended ECHO time (120 to 160 ms) T2w…
Portal venous gas
Always abnormalPresent when intestinal permeability increases or when there is increase in intestinal luminal pressureNeonatal necrotising enterocolitis, adults with gastric emphysema, intestinal obstruction, infection, Crohn diseaseBlunt abdominal trauma, invasive malignancies (colon, ovarian carcinoma)Duodenal perforation at ERCPColitis following barium enemaGas radiates out of hilumLess gravity dependence than pneumobilia, more peripheral distribution Imaging US: moving gas bubbles…
Hepatic steatosis
Increased triglyceride loading of hepatocytesAcute and chronic alcohol abuseObesityDiabetes mellitusInsulin resistanceCystic fibrosisMalnourishmentTotal parenteral nutritionTetracyclines, steroids, ileal bypass Imaging US: increased parenchymal reflectivity, obscures portal vein marginsCT: helps quantify. Fat reduces 1.6 HU for every mg of triglyceride increase per gram of liver substance. Preserved liver architecture and vascular pattern. Liver enhances normally post i.v. contrast.…
Hepatic encephalopathy
Patients with liver dysfunctionCirrhosis, portal hypertension, portal systemic shunts, acute liver failureMRI demonstrates CNS increase in certain substances that are normally metabolized by the liver Imaging MRIT1 high signal in globus pallidum due to excess manganeseElevated glutamate/glutamine peak with decreased myo-inositol and choline on spectroscopy. This is due to hyperammonemiaT1 high signal in anterior pituitaryWhite…
Porcelain gall bladder
0.2% of cholecystectomy specimensComplete or scattered mural calcification<5% chance of carcinoma of gall bladderProphylactic cholecystectomy recommended Imaging Calcification follows contour of gall bladderFocal or diffuseMimics emphysematous cholecystitis on ultrasound. ‘Double-arc shadow’ sign of stones is absent Read more Stephen, Antonia E., and David L. Berger. “Carcinoma in the porcelain gallbladder: a relationship revisited.” Surgery 129.6…
Acute calculous cholecystitis
Ultrasound is best initial investigation – definitive in 80% cases90-95% of cases of cholecystitis due to stones Imaging USGGall bladder wall thickness > 3 mm has 95% positive predictive valueGall bladder distension (diameter >5 cm)Pericholecystic fluidGall bladder wall striationsWall hyperemia occasionally on DopplerIf labs show signs of cholestasis, rule out CBD stoneCTLess accurateGall bladder wall…
Transplant pancreas imaging
Graft rejection is best demonstrated by MRIT1 drop in signal to similar to skeletal muscleT2 signal similar to fluid Perfusion studies will demonstrate decreased blood flowAcute rejection: Gland will be swollen with patchy areas of decreased attenuationChronic rejection: gland is diffusely hyper echoic and reduced in sizeTc 99m DTPA is also useful with 86% sensitivity Transplant pancreatitis…
Multi-system disease involving pancreas
Cystic fibrosis Autosomal recessiveDefects of serous and mucous secretion85% have exocrine pancreatic insufficiency, steatorrhea Main duct and branch ducts obstructed by inspissated secretionsAcinar and ductal dilatationAtrophy of pancreasFatty replacement, dystrophic calcification, pancreatic cysts Autosomal dominant polycystic kidney disease 10% patients show pancreatic cysts Von Hippel-Lindau disease Autosomal dominantRenal cell carcinoma, pheochromocytoma, retinal angiomatosis, hemangioblastoma in cerebellum Common…
Metastasis to pancreas
Rare, occur late in diseaseLung, breast, kidney and melanoma3 patterns described: multiple small nodules, diffuse infiltration, solitary massKidney origin lesions may appear hyper enhancing and mimic neuroendocrine tumors
Intraductal papillary mucinous tumor of pancreas (IPMT)
Most common cystic pancreatic neoplasm Arise from epithelial cells of main duct or side branches Produces large amount of mucin 4 histological types: dysplasia, borderline, carcinoma in situ, IPMT with invasive cancer Based on location: main duct type, branch duct type or mixed type Diffuse or segmental duct dilatation Mixed type shows diffuse and segmental duct dilatation Solid nodular protrusions or masses…
Serous cystic neoplasms of pancreas
Mass consisting of numerous tiny cysts, at least 6 in number, each cyst <2 cm in diameter May show central scar or stellate calcification If cysts too small to discern, it will appear as a solid mass. MRI clearly depicts the microcystic nature Very rarely it can appear in a macrocystic form and be difficult to distinguish from mucinous cystic neoplasms
Mucinous cystic neoplasms of pancreas
Benign to malignant, eventually turn malignant Mass consisting of few >2 cm sized cysts Any accompanying solid component suggests malignancy
Neuroendocrine tumors of pancreas
Functioning or non-functioning depending on hormonal hyper secretionFunctioning tumors produce a peptide hormone and has a clinical syndromeNon-functioning tumors have a better prognosisInsulinoma, gastrinoma, glucagonoma, VIPoma, somatostatinoma 20% NETs are partially cystic, 3% purely cystic Insulinoma Hypoglycemic episodesSolitary, benign80% cases <2 cm sizeTreated by surgical resection Gastrinoma Second most common NETCauses Zollinger-Ellison syndromeGastric hyperacidityRecurrent gastric and…
Ductal adenocarcinoma of pancreas
Aggressive Early advanced local or distant spreadPerivascular, perineurial and lymphatic spreadEarly spread to liver and peritoneumAt time of diagnosis, only 10% cases surgically resectable5 year survival rate <5%Radical pacreaticoduodenectomy – severe morbidity and mortalityWeight loss, anorexia common symptomsObstructive jaundice seen in tumors involving head of pancreasCA 19-9 is associated, but is neither sensitive nor specific Imaging …
Autoimmune pancreatitis
No history of alcohol use or biliary stone diseaseImmune-mediatedGland infiltrated by CD4 positive lymphocytes and plasma cellsSerum IgG4 sometimes elevatedResponds to steroidsFocal form difficult to distinguish from malignancyMay be associated with other IgG4 issues: cholangitis, renal, salivary gland or lacrimal gland inflammation, lymphadenopathy Imaging 3 types in imaging: diffuse, focal or multi-focalDiffuse most common 70%Diffuse…
Chronic pancreatitis
Irreversible inflammation and fibrosisMultiple prior attacks of acute diseaseAbdominal painLoss of exocrine and endocrine functionWeight loss, steatorrhea, diabetesDiagnosis made when 3 of the following 4 is presentParenchymal calcificationsIntraductal calcificationsParenchymal atrophyCystic lesionsFocal pancreatitis and malignancy in chronic pancreatitis are hard to distinguish on imaging. One sign described is the ‘duct penetrating sign’. The main duct traversing…
Acute pancreatitis
Some etiologies Alcohol, cholelithiasis, trauma, iatrogenic, hyperlipidemia, hypercalcemia, viral infections (CMV, mumps), drugs, idiopathic Clinical diagnosis Needs at least 2 of the 3 below: Abdomen pain strongly pointing to acute pancreatitisSerum amylase and or lipase at least 3 times upper limitCharacteristic imaging findings Revised Atlanta Classification (2008) Two morphological types: interstitial edematous and necrotising pancreatitis …
Annular pancreas
Second most common congenital anomalyFailure of normal rotation during developmentPancreas partially or completely encircles duodenumSometimes causes symptomatic duodenal narrowingBarium studies show narrowing at level of major papillaQuite often asymptomaticCT, MRI shows the tissue around second part of duodenumERCP or MRCP will show the duct encircling the duodenum
Pancreas divisum
Commonest congenital pancreatic abnormalityFailure of normal fusion of dorsal and ventral anlage Dorsal and ventral ducts don’t fuseWirsung (ventral duct) drains head of pancreas via major papillaSantorini (dorsal duct) drains body and tail via minor papillaCan cause functional stenosis of minor papilla and secondary pancreatitisHigher prevalence in patients with recurrent or chronic pancreatitis. Etiology is not…
Chronic calcific pancreatitis
Clinical presentation 38 year old gentleman presented with recurrent upper abdominal pain. CT https://www.youtube.com/watch?v=ovCmHfb3Q5c https://www.youtube.com/watch?v=aLXdvn284JM Findings and discussion https://www.youtube.com/watch?v=W1QzJ2E7a-Y Read more Chronic pancreatitis – Radiopaedia Busireddy, Kiran K., et al. “Pancreatitis-imaging approach.” World journal of gastrointestinal pathophysiology 5.3 (2014): 252.
Polycystic liver disease
Clinical presentation 45 year old gentleman, with family history of polycystic disease developed epigastric discomfort and came to assess present status of hepatic cysts. MRI Liver https://www.youtube.com/watch?v=vsvB_X5tIog https://www.youtube.com/watch?v=IvMAvG9yTrI https://www.youtube.com/watch?v=au-zg6CiXXU Key images Findings Multiple simple cysts of varying sizes are seen in both lobes of liver left > right, largest measuring 11 x 8.5 cm…
Flash hemangioma of the liver
30 year old gentleman went for a routine health check up as a part of his job health clearance and was detected to have a heteroechoic focal lesion in right lobe of liver. A multiphase contrast enhanced CT study was requested to identify the nature of the lesion. Triphasic CT Arterial phase https://www.youtube.com/watch?v=Oc_3XL4Typs Portal phase…