79 Magnetic Resonance Imaging of the Liver

CLINICAL IMAGAGINGAN ATLAS OF DIFFERENTIAL DAIGNOSIS

EISENBERG

DR. Muhammad Bin Zulfiqar PGR-FCPS III SIMS/SHL

• Fig GI 79-1 Hemorrhage in a simple hepatic cyst. T1-weighted image demonstrates a homogeneously hyperintense lesion, reflecting bleeding within the cyst.142

• Fig GI 79-2 Polycystic liver disease. (A) T1-weighted scan shows multiple cysts (C), some of which are hyperintense due to the presence of blood. T2-weighted image shows hemorrhagic cysts and noncomplicated cysts, with the former being less hyperintense than the latter, as is typically the case. The largest hemorrhagic cyst (C) is surrounded by a hypointense rim of hemosiderin. Note also the presence of ascites. (C) Corresponding unenhanced CT scan shows the multiple hepatic cysts. Note the calcifications in the wall of the single largest cyst (C).143

• Fig GI 79-3 Caroli's disease. (A) Axial T2-weighted image shows multiple hyperintense cystic ectasias (arrows) and calculi (arrowheads). (B) Corresponding unenhanced CT scan shows multiple stones (arrowheads) within dilated bile ducts (arrows).143

• Fig GI 79-4 Pyogenic abscess with perilesional edema. (A) T1-weighted image shows a mass with fluid-like signal intensity. (B) T2-weighted image shows a thick hyperintense rim (arrowheads), representing edema, surrounding the margin of the mass.144

• Fig GI 79-5 Pyogenic abscess. Coronal T2-weighted image shows the predominantly high-signal-intensity mass (arrows) hanging off the inferior aspect of the right hepatic lobe. Note the significant mass effect on adjacent bowel and soft tissues.145

• Fig GI 79-6 Amebic abscess. (A) T1-weighted image shows a heterogeneously hypointense and isointense mass in the right lobe of the liver. Note the deviation of the hepatic vasculature. An incomplete ring is seen within the wall of the abscess (arrows). (B) On the T2-weighted scan, the mass appears heterogeneously hyperintense and has an incomplete hyperintense ring (arrows). The abscess is surrounded by ill-defined zones of intermediate density. (C) After 10 days of medical treatment, a T1-weighted image shows that the abscess cavity is now homogeneously hypointense relative to liver and is bordered by a hyperintense ring surrounded by a hypointense ring (arrows). (D) T2-weighted scan taken at the same time shows the same hypointense ring about the lesion (arrows). This is bordered by a peripheral hyperintense ring that was not evident on the T1-weighted image. Note that the size of the abnormality is now the same on both images, indicating that the perifocal edema has largely resolved.146

• Fig GI 79-7 Fungal infection. (A) T1-weighted image shows multiple small, nodular, hypointense lesions with a “target” appearance and relatively increased central signal intensity. (B) Fat-saturated T2-weighted scan shows hyperintense nodular lesions, which correspond to the areas of hypointensity seen on the previous image. This patient with acute myelocytic leukemia showed a marked decrease in the number of liver lesions on follow-up scans.147

• Fig GI 79-8 Echinococcal cyst. T2-weighted image shows a hyperintense mass with a capsule of lower signal intensity in the right lobe of the liver (large arrow). The hyperintense paraaortic lymphadenopathy (small arrows) was due to tuberculous infection.147

• Fig GI 79-9 Echinococcal cyst. T1-weighted image shows a very large hydatid cyst with multiple small daughter cysts (arrows). The presence of daughter cysts may indicate early degenerative change of the mother cyst. The outer pericyst was better seen as a hypointense band on T2-weighted scans.145

• Fig GI 79-10 Echinococcal cyst. (A) T1-weighted and (B) fat-suppressed T2-weighted images show a fat-fluid level within the cyst.148

• Fig GI 79-11 Giant hemangioma. T2-weighted image shows a large mass in the right lobe of the liver that has homogeneous high signal intensity, similar to that of cerebrospinal fluid. Note the band of low signal intensity, representing fibrosis, coursing horizontally through the mass.149

• Fig GI 79-12 Hemangiomas. (A) T1-weighted image shows two hypointense, well-defined, lobulated peripheral lesions (arrows) in the right lobe of the liver. (B) On a heavily T2-weighted image, the lesions exhibit increased signal as the liver decreases in signal intensity. (C) T1-weighted image obtained within 2 minutes after contrast administration shows peripheral enhancement of the lesions. (D) Within 10 minutes after contrast, a repeat T1-weighted image demonstrates uniform, persistent enhancement of the lesions.150

• Fig GI 79-13 Hemangioma. (A) Initial T1-weighted image from a dynamic contrast study demonstrates peripheral nodular enhancement of the lesion (arrows). (B) There was progressive filling of the mass, though the central scar did not enhance.151

• Fig GI 79-14 Hepatocellular adenoma. (A) T1-weighted image shows a mass (arrows) in the right hepatic lobe that has slightly increased signal intensity relative to the liver. (B) Fat-suppressed T1-weighted scan demonstrates the lesion (arrows) to be hypointense to the liver, indicating the fatty nature of the mass. (C) T2-weighted image shows the mass to be slightly more intense than the surrounding liver.150

• Fig GI 79-15 Hepatocellular adenoma. T1-weighted image shows a central concentric rim of high signal intensity (subacute hemorrhage) surrounding an area of low signal intensity (acute bleeding). There is also a second area of low signal intensity in the left lobe of the liver.152

• Fig GI 79-16 Focal nodular hyperplasia. (A) T1-weighted image demonstrates a large mass in the right hepatic lobe with a hypointense central scar (arrowhead). (B) On the delayed-phase contrast scan, the tumor is slightly hyperintense (arrow) relative to the surrounding liver parenchyma (prolonged enhancement), with a hyperintense central scar (arrowhead).144

• Fig GI 79-17 Infantile hemangioendothelioma. (A) T1-weighted image obtained with the patient lying in a decubitus position demonstrates a large, multinodular liver lesion with heterogeneous signal intensity that fills the abdomen. (B) T2-weighted image shows the lesion to be predominantly of high signal intensity due to its vascular nature.150

• Fig GI 79-18 Lipoma. T1-weighted image demonstrates the hyperintense fatty lesion.142

• Fig GI 79-19 Biliary microhamartomas. (A) T2-weighted image shows innumerable high-signal-intensity liver lesions (arrowheads). (B) Corresponding CT scan shows multiple hypoattenuating cystic lesions in both lobes of the liver.143

• Fig GI 79-20 Hepatocellular carcinoma. (A) On a T2-weighted image, the mass has a high signal intensity, but the central scar has low signal intensity (arrow). (B) T1-weighted image after contrast shows the peripherally enhancing mass to have a central low intensity area of necrosis and scarring.149

• Fig GI 79-21 Hepatocellular carcinoma. Hemorrhage within the tumor (arrowheads) is hyperintense on both T1-weighted (A) and T2-weighted (B) images.145

• Fig GI 79-22 Fibrolamellar carcinoma. (A) T1-weighted gradient-echo image demonstrates a slightly hypointense mass with a central hypointense scar. (B) On a T2-weighted image, the mass is hyperintense and the scar remains hypointense. (C) Early and (D) delayed contrast images show that the mass initially enhances heterogeneously and then becomes increasingly homogeneous in the late phase.153

• Fig GI 79-23 Hepatoblastoma. (A) T1-weighted image shows the right hepatic mass to be of predominantly low signal intensity. Areas of increased signal intensity (arrows) represent hemorrhage. (B) T2-weighted image reveals the lesion to have increased signal intensity, with hypointense bands (arrows) representing fibrotic septations. Note the hyperintense necrotic area (arrowhead) compressing the inferior vena cava.150

• Fig GI 79-24 Intrahepatic cholangiocarcinoma. (A) STIR image shows a hyperintense well-defined tumor. The central scar is more hyperintense (arrow), and there is retraction of the liver capsule adjacent to the tumor (arrowhead). (B) After contrast administration, an acute phase scan shows enhancement at the periphery of the tumor, sparing the central scar. (C) On the delayed phase scan, there is complete, but heterogeneous, enhancement of the tumor.154

• Fig GI 79-25 Biliary cystadenoma. (A) Coronal T1-weighted and (B) axial T2-weighted images demonstrate a large cystic mass (arrowheads) compressing the adjacent normal liver tissue.120

• Fig GI 79-26 Angiosarcoma. T2-weighted image demonstrates heterogeneous high signal intensity of the central portion of a large right lobe liver mass. The peripheral areas of the lesion show only slight increased signal intensity.155

• Fig GI 79-27 Undifferentiated (embryonal) sarcoma. (A) T1-weighted image shows a mass of predominantly low signal intensity containing lobulated areas of increased signal intensity that correspond to regions of hemorrhage. (B) T2-weighted image shows the mass to be heterogeneous but predominantly of high signal intensity equal to or exceeding that of cerebrospinal fluid. The central lobulated areas of markedly increased signal intensity correspond to regions of gelatinous hemorrhagic degeneration.156

• Fig GI 79-28 Metastases from colon carcinoma. T2-weighted image shows several lesions with the target sign (arrow). The periphery of the lesions (viable tumor) is relatively hypointense compared with the center (liquefactive necrosis).157

• Fig GI 79-29 Hemorrhagic metastases from malignant melanoma. (A) T1-weighted image shows a well-circumscribed mass containing areas of high and low signal intensity. An ill-defined lesion is present in the posterior aspect of the right hepatic lobe (arrow). (B) T2-weighted image shows a persistent area of high signal intensity in the posterior aspect of the mass. In addition, a mass of intermediate signal intensity is identified in the left hepatic lobe (arrow). At surgery, multiple lesions were found in the liver. The dominant lesion in the right lobe contained multiple areas of hemorrhage. However, melanin could also produce high signal on T1-weighted images due to its paramagnetic characteristics.151

• Fig GI 79-30 Metastatic uterine leiomyosarcoma. (A) During the arterial phase, the lesion has a thin enhancing rim. (B) During the portal phase, the peripheral rim is less conspicuous, and the central portion of the tumor has become progressively more enhanced.157

• Fig GI 79-31 Metastases from colon carcinoma. (A) T1-weighted image shows multiple hypointense liver masses. (B) On a delayed-phase contrast scan, the masses demonstrate central enhancement and peripheral washout (arrowheads).144

• Fig GI 79-32 Fatty infiltration. (A) In-phase T1-weighted image shows homogeneously increased signal intensity of the liver. (B) Opposed-phase T1-weighted image shows reduced signal intensity of the liver, suggestive of fatty change.158

• Fig GI 79-33 Hepatitis. (A) T1-weighted image reveals diffuse atrophy and irregular surface of the liver. There is decreased signal intensity of the left lobe (arrows). (B) T2-weighted image shows segmental increase in signal intensity of the left lobe (arrows). (C) Contrast T1-weighted scan demonstrates a segmental area of enhancement (arrows), probably corresponding to segmental fibrosis.158

• Fig GI 79-34 Glycogen storage disease. (A) T1-weighted image shows homogeneously increased signal intensity of the hepatic parenchyma compared with that of bone marrow. Note the round high-signal-intensity tumor (arrow) in the lateral segment. (B) T2-weighted image shows the high-intensity signal of the tumor (arrow).158

• Fig GI 79-35 Hemosiderosis. T2-weighted fat-saturated image shows marked signal hypointensity in the liver in comparison with the muscles and spleen in a child who had undergone bone marrow transplantation for acute lymphoblastic leukemia. There is also evidence of ascites.159

• Fig GI 79-36 Hemochromatosis. (A) T2-weighted image shows decreased signal intensity of the liver, pancreas, and spleen when compared with that of paraspinal muscle. (B) T1-weighted image shows decreased signal intensity of the liver resulting from the T2 shortening effect.158

• Fig GI 79-37 Sarcoidosis. T2-weighted image obtained after the administration of ferumoxidex demonstrates multiple, small, high-signal-intensity nodules throughout the liver.160