IMAGING FEATURES OF GIT AND PANCREATIC

DISEASES

Plain film radiograph

Hepatic angle

Spenic angle

Renal shadow

Psoas muscle

Properitoneal fat strip

Normal CT anatomy

1.LHV, left hepatic vein

2.MHV, middle hepatic vein;

3.RHV, right hepatic vein;

4.IVC, inferior vena cava

5.Ao,aorta

6.Stomach

12

3 4 5 6

1.LPV, left portal vein

2.Stomach

3.Speen

4.IVC, inferior vena cava

5.Ao,aorta

5

2

3

1

4

1.Gallbladder

2.RPV, right portal vein

3.antrum

4.duodenal bulb

3

4

1

1

1.CA,celiac axis2.Splenic artery3.common hepatic artery4.Duodenum5.Kidney6.Pancreas7.Portal vein8.Adrenal gland

12

34

55

67

SMA:superior mesenteric artery

CBD,common bile duct

Spenic vein

Pancreas

SMV, superior mesenteric vein

SMA, superior mesenteric artery

Uncinate process

CTA

SMA, superior mesenteric artery

CA,celiac axis

Splenic artery

common hepatic artery

main portal trunk; right portal branch; splenic vein; inferior mesenteric

vein; superior mesenteric

vein

RHV, right hepatic vein;

MHV, middle hepatic vein;

LHV, left hepatic vein

IVC, inferior vena cava

pancreatic duct

Upper abdominal calcification

may be an important sign of disease Gallstones ,Porcelain gallbladder Urinary Calculi Calcified adrenal glands Pancreatic calcification Tumor calcification ……………

Gallstones 15% -20%of gallstones

contain sufficient calcium to be identified on plain film

right upper quadrant laminated appearance(a dense outer rim and more

radiolucent center)

Porcelain gallbladder

calcification in the wall of the gallbladder

indicative of chronic obstruction of the cystic duct, chronic gallbladder inflammation, and an increased risk of gallbladder carcinoma

diffuse Discontinuous mural calcification

Kidney stones About 85% of urinary calculi

are visible on plain film. Staghorn Calculus a large calculus occupying the

collecting system of the left kidney and assuming its shape

Calcified adrenal glands associated with

adrenal hemorrhage in the newborn, tuberculosis, and Addison disease

either side of the first lumbar vertebra

Pancreatic Calcifications

chronic alcohol-induced pancreatitis

Coarse and punctate calcifications

extend upward across the left upper quadrant

Diffuse Liver Disease  Fatty liver

Cirrhosis

Fatty liver(Steatosis) In normal adults, the precontrast attenuation value of the liver is

consistently higher than that of the spleen Milder degrees of diffuse steatosis :the attenuation value of the

liver is less than that of the spleen Marked diffuse steatosis :the liver parenchyma is lower in

attenuation than the hepatic blood vessels

The attenuation value of the liver parenchyma is markedly lower than that of the spleen

The intrahepatic vessels stand out as hyperattenuating structures

Focal fatty infiltration

The same imaging features as diffuse infiltration

Vessels run their normal course through the area of involvement

(lack of mass effect )

Cirrhosis hypertrophy of the caudate lobe and left lobe with shrinkage of

the right lobe

inhomogeneity of hepatic parenchyma,

irregularity (nodularity) of the liver surface,

Extrahepatic signs :evidence of portal hypertension, splenomegaly, and ascites

nodularity of the liver contour

atrophy of the medial segment (M) and enlargement of the lateral segment

prominent notch in the right posterior surface of the liver

Focal Liver diseases

Cyst Hemangioma Hepatocellular

carcinoma metastasis

Cyst:CT appearance

a well-circumscribed, homogeneous mass of near-water-attenuation value (less than 20 HU)

no enhancement after IV contrast medium administration

Two large well-circumscribed, homogeneous, near-water-density masses

no discernible wall

Hemangioma

the most common benign liver tumor

fed by hepatic artery branches

internal circulation is slow

generally remain stable in size over time

well-defined, hypodense on unenhanced scans Enhancement pattern : nodular enhancement

from the periphery of the lesion and proceeding toward the center gradually

Precontrast CT :an attenuation value similar to that of the blood in the inferior vena cava(IVC)

Arterial phase :multiple areas of globular, peripheral enhancement.

Note that the enhanced portions of the mass have an attenuation value similar to that of the intrahepatic vessels.

Equilibrium phase : near-complete enhancement of the mass with an attenuation value equivalent to that of the blood in the inferior vena cava(IVC) and hepatic veins

T2WI:marked hyperintense

Hepatocellular carcinoma

The most common primary malignancy of the liver Risk factors : cirrhosis, chronic hepatitis Growth patterns: solitary massive, multinodular, and diffuse

infiltrative Serum α-fetoprotein(AFP) levels are often

elevated

Hypervascular :contrast enhancement on arterial phase images, with diminishing enhancement on delayed phase images

Tumor thrombus

Tumor capsule: a sharply marginated rim

Necrosis: central low density

The satellite lesions

T2WI T1WI

AP PP DP

Portal Vein Thrombosis

Multiple hypodense nodules ----HCC

Filling defect with the vein

Metastases

The most common malignant masses in the liver Most commonly originate from the GI tract,

breast, and lung Necrosis, fibrosis, calcification, or hemorrhage

within the mass The most common enhancement

pattern :continuous ring-like enhancement

• Multiple

• Hypoattenuating lesions

with mild continuous rim

enhancement

T2WI:a central area of hyperintensity

rim enhancement

Normal MR Cholangiopancreatography (MRCP).

Biliary Dilatation

Diameter of intrahepatic bile ducts larger than 40% of the diameter of the adjacent portal vein

Dilation of the common duct greater than 6 mm Gallbladder diameter greater than 5 cm

Causes of Biliary Tract Obstruction

Choledocholithiasis approximately 20% of cases of obstructive jaundice in the adult

CT:high-density calcification within the duct

MRCP has shown good sensitivity (86% to 100%) and specificity (85% to 100%) for ductal stones

MRCP

Filling defects

Cholangiocarcinoma

arise from the epithelium of bile ducts and are usually adenocarcinomas

Growth patterns include mass forming, periductal infiltrating, and intraductal polypoid

• Mass forming

• periductal infiltrating

• Intraductal polypoid

Peripheral cholangiocarcinoma

Delayed enhancementbiliary dilatationAtrophy (liver)

Perihilar and extrahepatic cholangiocarcinomas

typically exhibit an infiltrating growth pattern focal, circumferential thickening of the bile duct with proximal

dilatation perihilar lesions may be similar in appearance to the intrahepatic,

mass-forming type of cholangiocarcinoma, or may manifest as an intraluminal polypoid mass

Pancreatic carcinoma a highly lethal tumor CT is recommended for initial imaging assessment CT:a hypodense mass that distorts the contour of the gland obstruction of the common bile duct and pancreatic duct and

atrophy of pancreatic tissue beyond the tumor

A B

C D

Signs of unresectability

tumor involvement of adjacent organs enlarged regional lymph nodes (>15 mm) encasement or obstruction of peripancreatic

arteries or veins metastases in the liver peritoneal carcinomatosis

Pancreatic Carcinoma: Nonresectable

encases and narrows the celiac axis and its branches

partially envelopes the aorta

Plain film radiographs of the abdomen are important for the assessment of the acute abdomen

CT, US, and MR provide comprehensive evaluation of the abdomen, including the peritoneal cavity, retroperitoneal compartments, abdominal and pelvic organs, blood vessels, and lymph nodes

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