Cystic peripheral cholangiocarcinoma: sonography and CT

A case of cystic peripheral cholangiocarcinoma is presented. Both sonography and computed tomography (CT) demonstrated a large intrahepatic cystic neoplasm containing an enhancing solid portion. Despite the very rare incidence of this tumor, we believe that cystic degeneration of peripheral cholangiocarcinoma should be considered with these radiologic findings.     

MR imaging in intracystic hemorrhage of simple hepatic cysts

Intracystic hemorrhage of simple hepatic cysts is one of the most frequent complications. Ul-trasonography (US) and computed tomography (CT) may show abnormal findings and mimic other diseases. We describe magnetic resonance (MR) imaging in four patients with intracystic hemorrhage confirmed by surgery or percutaneous aspiration. In all cases the lesions were hyperintense on both T1- and T2-weighted sequences. In three of the four cases the signal was heterogeneous on T1-weighted sequences. Two cases of a thickened wall and one case of a fluid-fluid level were also observed. We suggest that MR imaging may be helpful to differentiate intracystic hemorrhage from other cystic lesions by showing high signal on T1- and T2-weighted sequences.     

MR imaging of hepatocellular carcinoma at 1.5 Tesla

The authors investigated the magnetic resonance appearance of hepatocellular carcinoma using a 1.5-Tesla magnet. Twenty-four patients with pathologically proven hepatocellular carcinoma had magnetic resonance imaging (MRI) studies, which were retrospectively reviewed. All patients were imaged with at least two of the following techniques: (1) T1-weighted (T1W), (2) T1-weighted with Gd-DTPA enhancement (T1W-E), (3) T2-weighted (T2W), (4) proton density (PD), and (5) gradient-recalled echoes (GRE). T1W images were equal to T2W images for tumor detection using a grading system. T1W images were slightly better than T2W images for the total number of lesions detected. The other pulsing techniques (PD, T1W-E, and GRE) detected fewer lesions. Eight cases of hepatocellular carcinoma (33%) had nonhomogeneous increased signal intensity on both T1W and T2W images. The authors conclude that T1W images are equal to T2W images for detection of hepatocellular carcinoma. The authors also conclude that 33% of hepatocellular carcinomas have an imaging pattern with increased signal intensity on both T1W and T2W images. This pattern is atypical for most other hepatic masses and hence can be used to suggest the mass is hepatocellular carcinoma.     

MR imaging of malignant mesenchymal tumors of the liver

Magnetic resonance (MR) features of five primary malignant mesenchymal neoplasms (plasmocytoma, leiomyosarcoma, undifferentiated sarcoma, epithelioid hemangioendothelioma, and angiosarcoma) of the liver were reported. All tumors were hypointense on T1-weighted images and hyperintense on T2-weighted images. No halo and intravenous extension were noted. A target appearance was revealed in epithelioid hemangioendothelioma. MR findings of angiosarcoma were essentially the same as those of cavernous hemangiomas (markedly hyperintense with hypointense linear septa on T2-weighted images). MR findings of these rare hepatic malignancies were nonspecific, although they were quite different from those of typical hepatocellular carcinomas. This study suggested that MR differentiation of primary hepatic mesenchymal tumors from other common benign and malignant neoplasms was difficult; however, the number of studied cases was limited.     

Hodgkin's and non-Hodgkin's hepatic lymphoma: Sonographic findings

The sonographic studies of 72 patients with pathologically proven Hodgkin's or non-Hodgkin's hepatic lymphoma were retrospectively reviewed. Sixty-eight patients (94%) had secondary hepatic lymphoma (nine of them had AIDS-related lymphoma) and four patients (6%) had primary lymphoma of the liver. Forty-six of 72 patients (64%) had diffuse hepatic involvement, and 26 of 72 patients (36%) had focal liver lesions as demonstrated by sonography. Four patterns of disease were identified: (a) hepatomegaly was depicted by sonography in 26 of the 59 patients with secondary hepatic lymphoma not related to AIDS, in two of the nine patients with AIDS-related secondary hepatic lymphoma, and in one of the four patients with primary hepatic lymphoma; (b) multiple rounded well-delineated hypoechoic liver lesions were found in 22 of the 68 patients with secondary hepatic lymphoma; (c) a large heterogeneous echoic mass, which was an evocating clue to the diagnosis of primary lymphoma of the liver, was found in the four patients with primary lymphoma of the liver; and (d) an absence of sonographic abnormalities was found in 20 of the 59 patients with secondary lymphoma not related to AIDS. Liver involvement with lymphoma should be considered in any patient who develops multiple homogeneous hypoechoic liver masses, even in the absence of known underlying lymphomatous disease.     

Comparison of computed tomography and magnetic resonance imaging in the evaluation of focal hepatic lesions

Two combined magnetic resonance (MR) spin-echo pulse sequences at 0.35 T were compared with dynamic bolus contrast-enhanced computed tomography (CT) in the evaluation of focal hepatic lesions. Each combined MR sequence was performed in a separate group of patients. The first group consisted of 76 patients in whom a moderately T1-weighted sequence (spin echo [SE] 500/30 [repetition time/echo time]) was combined with a T2-weighted sequence (SE 2000/60). In the second group, consisting of 68 patients, a more heavily T1-weighted sequence (SE 250/15) was combined with the T2-weighted sequence. All studies were evaluated in a retrospective blinded fashion, with construction of receiver operating characteristic curves.We conclude that, in detection of patients with one or more focal hepatic lesions, either combined MR sequence was comparable to CT. In the detection of individual hepatic lesions, the sensitivity of the combined MR sequence with a moderately T1-weighted sequence (SE 500/30 and 2000/60) was essentially equivalent to CT (79 vs 77%, respectively). Additionally, a combined MR sequence with a heavily T1-weighted pulse sequence (SE 250/15 and 2000/60) was not statistically different than CT (86 vs 80%, respectively). These findings were supported by the receiver operating characteristic analysis.     

Complications of hepatic hydatid cysts: Ultrasound,computed tomography,and magnetic resonance diagnosis

A total of 179 hepatic hydatid cysts (HHCs) were studied by ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). The diagnosis of HHC complications was established by US and CT, which permitted a distinction between intact cysts and those presenting with contained rupture, as demonstrated by a collapsed endocyst or a globally echogenic appearance. The diagnosis of HHC perforation into the main biliary tree was made by detection of a discontinuity in the cyst wall and/or the presence of hydatid material within the biliary system. Similarly, direct HHC rupture into different thoracoabdominal spaces was diagnosed by demonstrating cyst wall discontinuity and the presence of hydatid material within these spaces. Ruptured and infected cysts were difficult to distinguish from ruptured cysts with sterile content. The role of MRI is yet to be defined in the assessment of HHC complications.     

Capsule and mosaic pattern of hepatocellular carcinoma: Correlation between CT and MR imaging

Computed tomography (CT) was compared with magnetic resonance (MR) imaging in depicting the capsule and the mosaic pattern of hepatocellular carcinoma in 34 patients. The kappa statistic was used to compare results from both modalities. For the detection of the capsule, there was a substantial agreement beyond chance between late enhanced CT (more than 5 min after dynamic CT) and MR imaging (kappa=0.76). Late enhanced CT and MR imaging had almost perfect agreement for the demonstration of the mosaic pattern (kappa=0.85). These agreements were better than the agreements between unenhanced CT and MR imaging or between early enhanced CT and MR imaging. These results suggest that late enhanced CT compares favorably with MR imaging in depicting the capsule and the mosaic pattern of hepatocellular carcinoma.     

Comparison between ultrasonographic signs and the degree of portal hypertension in patients with cirrhosis

The sensitivity of ultrasonography (US) for the diagnosis of portal hypertension was assessed in 48 patients with known cirrhosis. These results were compared to the hemodynamic values obtained on the same day by hepatic vein catheterization. The sensitivity of US in detecting portal hypertension was about 40% considering either a > 13 mm diameter of the portal vein, or the lack of mild caliber variation of the superior mesenteric vein. The sensitivity was more than 80% considering the presence of portosystemic venous collaterals. Presence of numerous portosystemic shunts was significantly associated with high hepatic venous pressure gradients which reflected the severity of portal hypertension.     

MR of the kidneys,liver, and spleen in paroxysmal nocturnal hemoglobinuria

The magnetic resonance (MR) findings in the liver, kidneys, and spleen in eight patients with paroxysmal nocturnal hemoglobinuria (PNH) were retrospectively reviewed to determine whether characteristic features could be demonstrated. Eight patients underwent abdominal MR examinations by gradient echo sequences (seven patients), spin-echo sequences (seven patients), and inversion recovery (one patient). Signal intensities of the kidneys, liver, and spleen were visually evaluated. Autopsy and liver biopsy correlation were available in one case each. Renal signal intensity was decreased in all eight patients by either gradient-echo or T2-weighted sequences and in the single inversion recovery sequence. Hepatic signal intensity was decreased in three of eight patients on spin- and gradient-echo images. Splenic signal intensity was decreased in three of eight patients on spin- and gradient-echo images, and in two of these was manifest as focal low signal spots (Gamna-Gandy bodies). While the signal intensity in the renal cortex is typically decreased in patients with PNH, signal intensities in the liver and spleen are variable. Low signal intensity in the kidneys is due to hemosiderin deposition resulting from intravascular hemolysis, whereas low signal intensity in the liver or spleen may be due to either transfusion siderosis, or as a consequence of hepatic or portal venous thrombosis.     

Ultrasound diagnosis of ruptured hydatid cyst of the liver with biliary obstruction

Communication between a hydatid cyst of the liver and biliary tract results in a clinical picture of obstructive jaundice because of occupation of the extrahepatic biliary tract by intracystic material. Five cases of this complication are presented. Ultrasound criteria for diagnosis are analyzed, based on previous publications as well as our own experience.     

Liver lesion detection: Comparison between excitation-spoiling fat suppression and regular spin-echo at 1.5T

The role of excitation-spoiling fat suppression (fatsat) imaging in the detection of liver lesions was assessed comparing short TR/TE and long TR/ TE spin-echo (SE) sequences with and without excitation-spoiling fat suppression in 25 patients at 1.5T. The study included patients with liver metastases (n = 21), primary liver cancer (n=3), and hepatic adenoma (n=1). Liver lesion detection and lesionliver signal-to-noise ratios (SNR) were determined for the various imaging sequences in a prospective fashion. Liver lesion-liver SNR were highest for long TR/TE (2000-2500/70-80) fatsat images (12.7±4.8) compared to long TR/TE regular SE (2000-2500/70-80) images (8.8±5.6) [(p = ns) (not significant)], short TR/TE (200-400/15-20) fatsat images (-6.2±4.8) (p=0.05), and short TR/TE regular SE images (-4.9±3.2) (p<0.01). Lesion detection was greatest for long TR/TE fatsat (86) followed by long TR/TE regular SE (78) (p=0.05), short TR/TE fatsat (65) (p<0.01), and short TR/TE regular SE (60) (p<0.01). The results of this study suggest that excitation-spoiling fat suppression may improve liver lesion detection and conspicuity.     

Dynamic contrast-enhanced MR imaging of fibrolamellar hepatocellular carcinoma

The magnetic resonance (MR) appearance of fibrolamellar hepatocellular carcinoma (FL-HCC) on T1- and T2-weighted and dynamic serial postgadolinium-DTPA images is reported. Both tumors were large (>7 cm in shortest dimension) and had central regions of low signal intensity on T1- and T2-weighted images. Diffuse heterogeneous enhancement of the tumors occurred on immediate postcontrast images. Lesions became more homogeneous in enhancement over time, but lack of enhancement of central portions of the tumor persisted. Although persistent lack of enhancement of the tumor scar on late postcontrast MR images may be characteristic of FL-HCC compared with delayed enhancement in focal nodular hyperplasia, the potential similarities between these tumors is stressed.     

Sonography and computed tomography of macroscopic tuberculosis of the liver

Four patients with macronodular tuberculosis of the liver were examined with ultrasonography. The findings included 1 case with multiple hypoechoic areas and 3 cases with a solitary lesion, one hypoechoic mass without calcifications, and two partially calcified masses. Some ultrasound features are suggestive: a mass with irregular calcifications, ascites, spleen enlargement with defects, enlarged nodes, and complete resolution of the lesions in a few months with effective antituberculous therapy. The first case was also examinated with computed tomography.     

MR findings of hepatic cavernous hemangioma after intraarterial infusion of iodized oil

Magnetic resonance (MR) imaging was performed on five tumors of three patients who had hepatic hemangiomas. Four tumors were given an intraarterial infusion of 3–8 ml of iodized oil, while one tumor was not. MR images were obtained at 2.0 or 0.5 T. A single spin echo sequence with TE of 30 ms and TR of 500 ms and a double echo sequence with TEs of 60 and 150 ms and TR of 2000 ms, were used to produce relatively T1-, T2-weighted, and heavily T2-weighted images, respectively. Follow-up MR imaging was done 1–5 months after infusion of iodized oil. On relatively T1 weighted images, hemangiomas showed iso or hypointensity. On T2-weighted images, all tumors showed hyperintensity. However, on heavily T2-weighted images, tumors with iodized oil showed heterogeneous, slight hyperintensity, while tumors without iodized oil showed characteristic appearance of marked hyperintensity in hemangiomas. In hepatic cavernous hemangiomas with intraarterial infusion of iodized oil, familiarity with this unusual MR intensity of tumors on heavily T2-weighted images is useful to avoid the incorrect diagnosis and to reduce the frequency of inappropriate hepatic resection.     

Alcoholic liver disease: Value of the left-to-right portal vein ratio in its sonographic diagnosis

A study group of 50 patients in whom the left portal vein diameter was equal to or greater than the right portal vein diameter (LPVDRPVD) was prospectively compared on ultrasonography with a control group of 50 patients with LPVD < RPVD. Clinical and laboratory data indicating chronic alcoholic liver disease (CALD) were observed with a significantly higher frequency in the study group than in the control group. It emerges from this study that LPVD RPVD represents a useful ultrasonographic sign of CALD, corresponding to a relative enlargement of the left hepatic lobe compared with the right.     

Accumulation of iron oxide particles around liver metastases during MR imaging

The histologic nature of the bright ring (peritumoral edema) around some liver metastases on T2-weighted magnetic resonance (MR) images is controversial. In the case reported, particles of the iron oxide contrast agent AMI-25 are retained in the peritumoral zone of a colon cancer metastasis, causing the bright ring to disappear. The location of iron particles in resected specimens could be used systematically to study peritumoral edema.     

Hepatic vein involvement in hepatocellular carcinoma

A retrospective review of the dynamic computed tomography (CT) and ultrasound scans from examinations of 134 patients with hepatocellular carcinoma was undertaken with emphasis on evaluation of hepatic vein involvement. Hepatic veins were involved in 8 patients (5.9%). Portal vein obstruction was associated in 7 of these cases. Sonography demonstrated hepatic vein involvement in 6 cases was considered within normal limits in 1 and failed to display hepatic veins in another. Dynamic CT was superior in depicting venous obstruction in all the cases by different signs including (a) hypodensity and enlargement of the vessel, (b) perivenous arterial hypervascularization surrounding the hypodense intraluminal region, and (c) hemokinetic changes in relation to the outflow obstruction. The frequency and significance of these CT signs are discussed and correlated in 2 patients with magnetic resonance imaging (MRI) data.     

Evaluation of intrahepatic cholestasis with radionuclide hepatobiliary imaging

Since hepatobiliary imaging with^99mTc=labeled iminodiacetic acid derivatives (HIDA) allows relatively separate, sequential measurement of hepatocyte clearance, parenchymal transit, and biliary excretion, these agents should be useful in differentiating intrahepatic cholestasis (IC) from other hepatobiliary disorders. We studied 18 patients with clinical evidence of IC in whom the parenchymal transit time was increased disproportionately to any decrease in hepatocyte clearance. In a second group of 14 patients with hepatocyte disease but without clinical evidence of IC, the average parenchymal transit time was increased less in relation to the average decrease in hepatocyte clearance than in the IC group. In 15 patients with extrahepatic biliary obstruction, the average hepatocyte clearance was disproportionately increased, as in IC, but large-duct obstruction was identified by scintigrams, ultrasound, or computed tomography. These preliminary results suggest that IC can be diagnosed with hepatobiliary imaging.