GI - Solid Organs

Hepatomegaly
-CT
-liver is massive and takes up most of the abdomen
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Terms in this set (133)
Hepatomegaly
-CT
-liver is massive and takes up most of the abdomen
Image: Hepatomegaly -CT -liver is massive and takes up most of the abdomen
Liver Steatosis
-USG
-increased hepatic echogenicity
-hyperattenuation of the beam
Image: Liver Steatosis -USG -increased hepatic echogenicity -hyperattenuation of the beam
Liver Steatosis
-CT
-decreased attenuation pre-contrast and post-contrast
Image: Liver Steatosis -CT -decreased attenuation pre-contrast and post-contrast
Liver Steatosis
-CT
-decreased attenuation pre-contrast and post-contrast
Image: Liver Steatosis -CT -decreased attenuation pre-contrast and post-contrast
Liver Cirrhosis
-USG is a major screening tool for cirrhosis
-surface nodularity
-overall coarse and heterogeneous echotexture
Image: Liver Cirrhosis -USG is a major screening tool for cirrhosis -surface nodularity -overall coarse and heterogeneous echotexture
Liver Cirrhosis
-CT is insensitive in early cirrhosis
-regenerative nodules (majority): isodense/hyperdense to the rest of liver
-siderotic nodules (minority): hyperdense due to accumulation of iron
-parenchymal heterogeneity both on the pre and post IV contrast
Image: Liver Cirrhosis -CT is insensitive in early cirrhosis -regenerative nodules (majority): isodense/hyperdense to the rest of liver -siderotic nodules (minority): hyperdense due to accumulation of iron -parenchymal heterogeneity both on the pre and post IV contrast
Liver Cirrhosis
-CT is insensitive in early cirrhosis
-regenerative nodules (majority): isodense/hyperdense to the rest of liver
-siderotic nodules (minority): hyperdense due to accumulation of iron
-parenchymal heterogeneity both on the pre and post IV contrast
Image: Liver Cirrhosis -CT is insensitive in early cirrhosis -regenerative nodules (majority): isodense/hyperdense to the rest of liver -siderotic nodules (minority): hyperdense due to accumulation of iron -parenchymal heterogeneity both on the pre and post IV contrast
Liver Cirrhosis
-CT is insensitive in early cirrhosis
-regenerative nodules (majority): isodense/hyperdense to the rest of liver
-siderotic nodules (minority): hyperdense due to accumulation of iron
-parenchymal heterogeneity both on the pre and post IV contrast
Image: Liver Cirrhosis -CT is insensitive in early cirrhosis -regenerative nodules (majority): isodense/hyperdense to the rest of liver -siderotic nodules (minority): hyperdense due to accumulation of iron -parenchymal heterogeneity both on the pre and post IV contrast
Liver Cirrhosis
-MRI is also insensitive in early cirrhosis but has a significant role in screening cirrhotic livers for small HCC
T1: variable, usually isointense occasionally mildly hyperintense
T2: usually isointense, hypointense if siderotic
Image: Liver Cirrhosis -MRI is also insensitive in early cirrhosis but has a significant role in screening cirrhotic livers for small HCC T1: variable, usually isointense occasionally mildly hyperintense T2: usually isointense, hypointense if siderotic
Liver Trauma
Image: Liver Trauma
Liver Cirrhosis -MRI is also insensitive in early cirrhosis but has a significant role in screening cirrhotic livers for small HCC T1: variable, usually isointense occasionally mildly hyperintense T2: usually isointense, hypointense if sideroticLiver Trauma -CT Liver fracture: linear or stellate-like (star) shape, low density area -blood has a lower density than enhanced liver -clotted blood or contrast-filled active hemorrhage may be as dense or denser than enhanced liverSimple Liver Cyst -USG -sharply defined round mass with a thin wall that is echo-free compared with normal echogenic liver parenchyma -can be hypoechogenic (complicated cyst)Simple Liver Cyst -CT -hypodense compared to normal parenchyma -sharply defined margin, thin wall -calcium in some portions of cyst wall produces a white borderSimple Liver Cyst -CT -hypodense compared to normal parenchyma -sharply defined margin, thin wall -calcium in some portions of cyst wall produces a white borderSimple Liver Cyst -CT -hypodense compared to normal parenchyma -sharply defined margin, thin wall -calcium in some portions of cyst wall produces a white borderSimple Liver Cyst -CT -hypodense compared to normal parenchyma -sharply defined margin, thin wall -calcium in some portions of cyst wall produces a white borderSimple Liver Cyst -CT -hypodense compared to normal parenchyma -sharply defined margin, thin wall -calcium in some portions of cyst wall produces a white borderSimple Liver Cyst -CT -hypodense compared to normal parenchyma -sharply defined margin, thin wall -calcium in some portions of cyst wall produces a white borderSimple Liver Cyst -CT -hypodense compared to normal parenchyma -sharply defined margin, thin wall -calcium in some portions of cyst wall produces a white borderLiver Cavernous Hemangioma (benign) -USG -can be single or multiple -usually hyperechogenic, some can be hypoechogenic or mixedLiver Cavernous Hemangioma (benign) -CT -lesion that fills in from periphery to center after a bolus of contrast -hyperdense after contrastLiver Cavernous Hemangioma (benign) -CT -lesion that fills in from periphery to center after a bolus of contrast -hyperdense after contrastLiver Cavernous Hemangioma (benign) -CT -lesion that fills in from periphery to center after a bolus of contrast -hyperdense after contrastLiver Cavernous Hemangioma (benign) -MRI T1 -T1 is hypointenseLiver Cavernous Hemangioma (benign) -MRI T2 -T2 is hyperintense, with central irregular regions that are even more T2 hyperintenseLiver Focal Nodular Hyperplasia -regenerating tissue in response to injury etc -CT -multiple masses shown as lobular enhancing nodules -~50% have a central stellate (star) area - scar does not enhanceLiver Focal Nodular Hyperplasia -regenerating tissue in response to injury etc -CT -multiple masses shown as lobular enhancing nodules -~50% have a central stellate (star) area - scar does not enhanceLiver Abscess -USG -focal mass -hypoechogenicity -thicker wall than a cyst wall -often multiloculatedLiver Abscess -CT -less dense than normal parenchyma -thick irregular walls -dot of gas produced by the gram negative bacteriaLiver Abscess -CT -less dense than normal parenchyma -thick irregular walls -dot of gas produced by the gram negative bacteriaLiver Abscess -MRI TI: usually hypointense centrally, heterogeneous, maybe slightly hyperintense in fungal abscess, after contrast = enhancement of capsule and segmentations may be visible T2: usually hyperintenseLiver Abscess -MRI TI: usually hypointense centrally, heterogeneous, maybe slightly hyperintense in fungal abscess, after contrast = enhancement of capsule and segmentations may be visible T2: usually hyperintenseTypes of hepatocellular carcinoma (hepatoma)1. Hepatocellular carcinoma 2. Hepatoblastoma 3. Metasteses 4. Cholangiocarcinoma 5. Gallbladder carcinomaTypes of malignant liver and biliary tract tumors (5)Hepatocellular carcinoma -occurs in adults -associated with hepatitis, cirrhosis, malnutrition, parasitic liver disease, recurrent pyogenic cholangitis -highy vascular -often have fibrous outer room75% of all primary malignant tumors of the liverHepatocellular Carcinoma -USG -hypoechogenic, hyperechogenic, or complex massHepatocellular Carcinoma -CT -usually transient, intense contrast enhancement -usually the mass enhances vividly during late arterial (~35 seconds) and then washes out rapidly, becoming indistinct or hypoattenuating in the portal venous phase, compared to the rest of the liverHepatocellular Carcinoma -CT -usually transient, intense contrast enhancement -usually the mass enhances vividly during late arterial (~35 seconds) and then washes out rapidly, becoming indistinct or hypoattenuating in the portal venous phase, compared to the rest of the liverHepatocellular Carcinoma -MRI T1: variable, iso- or hypointense cf. surrounding liver, contrast enhancement is usually arterial T2: variable, typically moderately hyperintenseColon Lung Breast Melanoma Carcinoid Choriocarcinoma Leiomyosarcoma Renal cellCancers that metastasize to the liverLiver Metastases -USG -mostly hypoechogenic, can be iso- or hyperechogenicLiver Metastases -CT -contrast enhanced markedly -typically hypoattenuating on unenhanced CTLiver Metastases -CT -contrast enhanced markedly -typically hypoattenuating on unenhanced CTLiver Metastases -CT -contrast enhanced markedly -typically hypoattenuating on unenhanced CTLiver Metastases -CT -contrast enhanced markedly -typically hypoattenuating on unenhanced CTLiver Metastases -CT -contrast enhanced markedly -typically hypoattenuating on unenhanced CTLiver Metastases -CT -contrast enhanced markedly -typically hypoattenuating on unenhanced CTLiver Metastases -MRI T2: high intensity STIR: high intensity T1: low intensityCholedocholithiasis -USG -hyperechogenic stones and acoustic shadow behind stones -dilated bile ductsCholedocholithiasis -MRCPEndoscopic Retrograde Cholangiopancreatography -involves canulation under fluoroscopic guidance, of the common bile duct and pancreatic ducts via the ampulla of vater during upper endoscopy -contrast injected into the lower common bile duct can show pathologyWhat is ERCP?ERCPWhat kind of imaging is this?Choledocholithiasis -ERCPCholedocholithiasis -ERCPCholedocholithiasis -ERCPCholedocholithiasis -ERCPCholangitis -MRICholangitis -MRCPCholangitis -MRCPCholangitis -MRCPCholangiocarcinoma -USG *The appearance will vary according to the growth pattern: Mass-forming intrahepatic: tumors will be a homogeneous mass of intermediate echogenicity with a peripheral hypoechoic halo of compressed liver parenchyma. They tend to be well delineated but irregular in outline and are often associated with capsular retraction 2 which, if present, is helpful in distinguishing cholangiocarcinomas from other hepatic tumors. Periductal infiltrating intrahepatic: tumors typically are associated with altered caliber bile duct (narrowed or dilated) without a well-defined mass. Intraductal: tumors are characterized by alterations in duct caliber, usually duct ectasia with or without a visible mass. If a polypoid mass is seen, it is usually hyperechoic compared to surrounding liverCholangiocarcinoma -CT *The appearance will vary according to the growth pattern: Mass-forming cholangiocarcinomas: these are typically homogeneously low in attenuation on non-contrast scans, and demonstrate heterogeneous minor peripheral enhancement with gradual centripetal enhancement Periductal infiltrating: intrahepatic tumors appear as regions of duct wall thickening or of the periductal parenchyma, with altered caliber of the involved duct (usually narrowed). These are most common at the hepatic hilum. Show contrast enhancement Intraductal tumors: these are characterized by alterations in duct caliber, usually duct ectasia with or without a visible mass. If a polypoid mass is seen it is hypoattenuating on pre-contrast imaging and demonstrates enhancementAerocholia -CTNormal gallbladder -USGGallbladder hydrops -USG -hydrops is a mucocele >4 cm transverse measurement >9 cm longitudinal measurement straight or convex bordersGallbladder hydrops -CT -hydrops is a mucocele ->4 cm transverse measurement >9 cm longitudinal measurement straight or convex bordersGallstones -USG -hyperechogenic stones and acoustic shadows behind the stonesGallstones -USG -hyperechogenic stones and acoustic shadows behind the stonesGallstones -USG -hyperechogenic stones and acoustic shadows behind the stonesGallstones -CT -Calcified gallbladder stones are hyperattenuating to bile, making them the only type to be clearly visualized on CT scan images -Pure cholesterol stones are hypoattenuating to bile -other gallstones are isodense to bile and these may not be clearly identified on CTGallstones -MRI T1-weighted 3D fast spoiled gradient echo (3D FSPGR): pigmented stones (hyperintense), cholesterol stones (hypointense) T2: signal void or low signal outlined by markedly hyperintense bile within the gallbladderGallstones -CT -Calcified gallbladder stones are hyperattenuating to bile, making them the only type to be clearly visualized on CT scan images -Pure cholesterol stones are hypoattenuating to bile -other gallstones are isodense to bile and these may not be clearly identified on CTAcute Calculous Cholecystitis -USG -uniform wall thickening, >3mm, distended gallbladder -gallstones seen in 93% of patientsAcute Acalculous Cholecystitis -USG -uniform wall thickening, >3mm, distended gallbladder -NO stonesAcute Calculous Cholecystitis -CTGallbladder empyema -USGan uncommon complication of cholecystitis and refers to a situation where the gallbladder lumen is filled and distended by purulent material (pus)What is gallbladder empyema?Gallbladder empyema -USGChronic Cholecystitis -USGChronic Cholecystitis -CT -The most commonly observed cross-sectional imaging findings in the setting of chronic cholecystitis are cholelithiasis and gallbladder wall thickening. The gallbladder may appear contracted or distended, and pericholecystic inflammation is usually absentGallbladder polyp -USGGallbladder carcinoma -USG -can depict a focal intraluminal, wall involvement, or large mass-like lesion replacing the gallbladder -usually irregular and ill-defined margins -heterogenous echotexture and predominantly low echogenicity -hyperechoic foci with posterior acoustic shadowing may be seen within the massGallbladder carcinoma -CT -large heterogeneous masses, may have engulfed gallstones or areas of necrosis -patchy moderate contrast enhancement is usually seenNormal pancreas -USGNormal pancreas -CTNormal pancreas -MRIPancreatic cystic lesion -CTEdematous Pancreatitis -USG -low echogenicity due to edemaEdematous Pancreatitis -CT -low density appearance1. Edematous 2. NecrotizingWhat are the two types of acute pancreatitis?1. the gland is enlarged and swollen 2. necrosis and hemorrhage are absent 3. the inflammation involves the parenchyma and the adjacent soft tissue 4. the ducts are not involvedFeatures of edematous pancreatitis (4)Edematous Pancreatitis -CT -low density appearance1. characterized by necrosis and hemorrhage 2. involves the entire gland, including the ducts 3. fat necrosis 4. fluid around the pancreasFeatures of necrotizing pancreatitis (4)Necrotizing Pancreatitis -CT -enlarged pancreas -diffuse or local areas of low density -dilatation of the pancreatic duct -pseudocyst, small gas bubbles -higher fat density than usualNecrotizing Pancreatitis -CT -enlarged pancreas -diffuse or local areas of low density -dilatation of the pancreatic duct -pseudocyst, small gas bubbles -higher fat density than usualNecrotizing Pancreatitis -CT -enlarged pancreas -diffuse or local areas of low density -dilatation of the pancreatic duct -pseudocyst, small gas bubbles -higher fat density than usual-An encapsulated cyst, filled with fluid and pancreatic secretions -Forms when obstruction and inflammation of pancreatic ducts cause extravasation of digestive enzymes into the pancreatic parenchymaWhat is a pancreatic pseudocyst?Pancreatic Pseudocyst -USG - large, dilated cystic cavities -Hypoechoic or anechoic collections, with dependent low-level echoes representing debris, are often seenPancreatic Pseudocyst -CT -large, dilated cystic cavities -appear as well-circumscribed, usually round or oval peripancreatic fluid collections of homogeneously low attenuation, that are usually surrounded by a well-defined enhancing wallPancreatic Pseudocyst -CT -large, dilated cystic cavities -appear as well-circumscribed, usually round or oval peripancreatic fluid collections of homogeneously low attenuation, that are usually surrounded by a well-defined enhancing wallPancreatic Pseudocyst -CT -large, dilated cystic cavities -appear as well-circumscribed, usually round or oval peripancreatic fluid collections of homogeneously low attenuation, that are usually surrounded by a well-defined enhancing wallPancreatic Pseudocyst -CT -large, dilated cystic cavities -appear as well-circumscribed, usually round or oval peripancreatic fluid collections of homogeneously low attenuation, that are usually surrounded by a well-defined enhancing wallPancreatic Pseudocyst -CT -large, dilated cystic cavities -appear as well-circumscribed, usually round or oval peripancreatic fluid collections of homogeneously low attenuation, that are usually surrounded by a well-defined enhancing wallPancreatic Pseudocyst -CT -large, dilated cystic cavities -appear as well-circumscribed, usually round or oval peripancreatic fluid collections of homogeneously low attenuation, that are usually surrounded by a well-defined enhancing wallChronic Pancreatitis -USG --Diffuse edematous or necrotic tissue mass in or around the pancreas -Complication of pancreatitis -can be confused with a pseudocystWhat is a pancreatic phlegmon?Chronic Pancreatitis -USG -pancreas might appear atrophic, calcified or fibrotic -hyperechogenicity (often diffuse) often indicates fibrotic changes -pseudocysts -pseudoaneurysms -presence of ascitesChronic Pancreatitis -USG -pancreas might appear atrophic, calcified or fibrotic -hyperechogenicity (often diffuse) often indicates fibrotic changes -pseudocysts -pseudoaneurysms -presence of ascitesChronic Pancreatitis -plain radiographPancreatic phlegmon -CTChronic Pancreatitis -CT -dilatation of the main pancreatic duct -pancreatic calcification -changes in pancreatic size (i.e. atrophy), shape, and contour -pancreatic pseudocystsChronic Pancreatitis -CT -dilatation of the main pancreatic duct -pancreatic calcification -changes in pancreatic size (i.e. atrophy), shape, and contour -pancreatic pseudocysts1. Cystadenoma 2. Islet cell adenomas: Insulinoma, gastrinoma, VIPoma, glucagonoma, somatostatinomaNames of benign pancreatic tumors (2)Insulinoma (60-75%)Most common islet cell adenoma1. Adenocarcinoma 2. Some Islet cell adenomasNames of malignant pancreatic tumors (2)Pancreatic neoplasm -USG -hypoechoic -irregular shapePancreatic neoplasm -USG -hypoechoic -irregular shapePancreatic neoplasm -single contrast plain radiographPancreatic neoplasm -CTPancreatic neoplasm -MRIPancreatic neoplasm -MRIPancreatic neoplasm -MRIPancreatic Islet Cell Adenoma -CT -very small, hypervascular masses -hyperdense after contrast -may be calcifiedNormal spleen -CTSplenomegaly -CTSpleen Lymphoma -CT -splenomegaly is most common feature, but can also be normal -post-contrast images: the focal lesions are hypoenhancing compared to the background parenchymaSplenic Infarction -CT -peripheral, wedge-shaped hypoenhancing region: typical multiple infarcts appear as hypodense non-enhancing lesions, with normal intervening enhancing splenic tissue -global splenic infarction, entire spleen is hypoenhancing, e.g. in splenic torsionSplenic Infarction -MRISplenic Calcification -CT -small hyperdense massesSplenic Calcification -CT -small hyperdense massesAscites -CT -hypodense in majority of the peritoneumAscites -CT -hypodense