Marc Levesque

MRI of liver metastases from colorectal cancer vs. CT during arterial portography.

A prospective study was performed to compare, with a lesion-by-lesion analysis, the sensitivities of high field strength MRI and CT during arterial portography (CTAP) in detecting hepatic metastases from colorectal cancer. Twenty-one patients with liver metastases from colorectal cancer were prospectively investigated by high field strength MRI (1.5 or 2 T) and CTAP. High field strength MRI was performed with pre and post gadopentetate dimeglumine enhanced T1-weighted SE sequences and T2-weighted SE sequences. All patients underwent partial hepatectomy and 37 metastases were surgically and pathologically proved. The metastasis detection rate (sensitivity) was 94% (35 of 37) for CTAP and 78% (29 of 37) for high field strength MRI. The 16% (95% confidence interval: 1–31%) difference in sensitivity between CTAP and high field strength MRI was statistically significant (p < 0.05, Mc-Nemar test). The use of gadopentetate dimeglumine did not improve the sensitivity of T1-weighted SE sequences. Since our study demonstrated significant difference in sensitivities between high field strength MRI and CTAP in our group of patients, we can conclude that high field strength MRI cannot replace CTAP in the preoperative evaluation of patients with liver metastases from colorectal cancer. Computed tomography during arterial portography must be considered as the preoperative gold standard. Index Terms: Liver, neoplasms—Portography—Magnetic resonance imaging, techniques.

MRI of Budd-Chiari syndrome

A retrospective study was undertaken to reassess the various magnetic resonance imaging (MRI) features of Budd-Chiari syndrome (BCS). MRI examinations of 22 patients with pathologically confirmed BCS were studied. Spin-echo (SE) T1- (TR = 300–450 ms/TE = 12–15 ms), and SE T2-weighted (TR = 1600–2000 ms/TE = 30–60/90–120 ms) MRI images were obtained in all patients. Gradient-recalled-echo (GRE) images (TR = 7–60 ms/TE = 3–19 ms, flip angle = 10–40°) were obtained in 14 patients. MRI showed thrombosis of three or two hepatic veins in 19 (86%) and 3 (14%) patients, respectively. Spontaneous intrahepatic anastomoses was depicted in five (23%) patients. Ascites appeared in 15 patients (68%). Thrombosis or external compression of the inferior vena cava (IVC) by an enlarged caudate lobe was depicted in six (27%) and five (23%) patients, respectively. Prominent azygos and hemiazygos veins were demonstrated in seven (32%) patients (six of whom had thrombosis of the IVC). MRI showed hepatomegaly in all patients and enlarged caudate lobe in 18 (82%) patients. SE T1- and SE T2-weighted MRI images revealed inhomogeneous signal intensity of hepatic parenchyma in 14 (64%) patients. SE T1- and SE T2-weighted MRI images showed homogeneous signal intensity of hepatic parenchyma in eight (36%) patients. Our results demonstrate that BCS displays various features on MRI images, and such information is important for diagnosis.

CT of fibrolamellar hepatocellular carcinoma.

We retrospectively evaluated 10 patients with pathologically proven fibrolamellar hepatocellular carcinoma (FLHCC) to assess the utility of CT (n = 9), ultrasound (n = 10), angiography (n = 9), and MR (n = 3). The tumors were solitary in 6 of 10 patients, well delineated in 7 of 10, and hypervascular in 8 of 10. With use of multimodality imaging techniques, a central scar was demonstrated in 3 of 10 patients, calcifications in 4 of 10, dilated intrahepatic ducts in 2 of 10, thrombosis of a segmental portal branch in 2 of 10, and lymph node involvement in 3 of 10. Computed tomography was the most accurate technique for diagnosis and staging. Magnetic resonance imaging helped establish the correct diagnosis in one patient. This report emphasizes the wide variability of imaging features of FLHCC and the predominant role of CT for suggesting the diagnosis.

Cystic Tumors of the Pancreas - Dynamic Ct Studies

Objective Our retrospective study was performed to reassess the common dynamic CT manifestations of cystic tumors of the pancreas and to determine whether they might allow the differentiation between benign and malignant tumors. Materials and Methods Dynamic CT examinations of 19 patients with 20 cystic tumors of the pancreas, including 7 serous cystadenomas, 3 benign mucinous cystadenomas, 5 mucinous cystadenocarcinomas, 3 mucin-producing duct ectasias, and 2 papillary cystic epithelial neoplasms, were retrospectively reviewed. The examinations were obtained with 4 to 5 mm collimation with intravenous injection of 120–130 ml of contrast agent. Results Calcifications were found only in benign tumors (seven serous cystadenomas). Internal septations were found in benign and malignant tumors (seven serous cystadenomas, three benign mucinous cystadenomas, three mucinous cystadenocarcinomas). Solid excrescences within cystic cavities were found only in malignant tumors (two mucinous cystadenocarcinomas, two mucin-producing duct ectasias). Dynamic CT features allowed the distinguishing of serous cystadenomas from other cystic tumors and mucin-producing duct ectasias from other mucinous tumors. Dynamic CT features did not permit differentiation between benign mucinous cystadenomas, mucinous cystadenocarcinomas, and papillary cystic epithelial neoplasms. Conclusion The review suggests that dynamic CT findings are useful to differentiate (a) serous cystadenomas and mucin-producing duct ectasias from other cystic tumors of the pancreas and (b) benign from malignant tumors. Such differentiation has impact on patient management.

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

The sonographic studies of 72 patients with pathologically proven Hodgkins or non-Hodgkins 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.

Primary lymphoma of the liver: MR findings

Primary lymphoma of the liver is a rare disease. The MR appearances of three cases of pathologically confirmed primary non-Hodgkins lymphoma of the liver are presented. All three lymphomatous lesions appeared as unique well demarcated focal liver lesions on MR images. On T1-weighted images, two lesions were hypointense and one slightly hyperintense to the liver. On T2-weighted images, the three lesions were slightly heterogeneous and hyperintense. Lobulation, which was better seen on T2-weighted images, was noticed in one lesion. One lesion was studied after gadopentetate dimeglumine injection and showed marked and heterogeneous enhancement.

High-resolution sonographic guidance for transjugular liver biopsy

A prospective randomized study was performed to compare conventional right internal jugular vein catheterization technique with high-resolution sonographically guided catheterization for transjugular liver biopsy. Forty-seven patients were assigned to undergo either conventional or high-resolution sonographically guided right internal jugular vein catheterization for transjugular liver biopsy. Sonographic guidance was significantly better than conventional guidance, reducing the number of failed catheterizations from 22% (5 of 23) to 0% (0 of 24) (p<.05). Sonography also reduced the mean number (± SD) of passes required to catheterize the vein from 4.21±1.53 to 1.54±0.66 (p<.001) and was successful in 100% (5 of 5) of patients in whom conventional catheterization failed. High-resolution sonographic guidance is strongly recommended for transjugular liver biopsy in patients at high risk for bleeding.

MRI of adenomatous hyperplastic nodules of the liver in Budd-Chiari syndrome.

We present two cases of adenomatous hyperplastic nodules (AHN) occurring in patients with chronic Budd-Chiari syndrome who were investigated with MRI. In one case the foci of AHN were isointense to the liver on spin echo (SE) T1-weighted MRI and were hyperintense on both SE proton density and SE T2-weighted MRI. In the other case the nodules were hyperintense on SE T1-weighted MRI. They were isointense on SE proton density-weighted MRI and became slightly hyperintense on SE T2-weighted MRI. Furthermore, in both cases one nodule displayed hyperintensity with hypointense rims on SE T2-weighted MRI.

Involvement of superior mesenteric vessels and portal vein in pancreatic adenocarcinoma: Detection with CT during arterial portography

A prospective study was designed to determine the utility of computed tomography (CT) during arterial portography (CTAP) in the detection of superior mesenteric vessels and portal vein involvement in patients with pancreatic adenocarcinoma. Eighteen patients with adenocarcinoma of the head of the pancreas and eight patients with benign pancreatic disease were investigated with CTAP, dynamic contrast-enhanced CT, and angiography. Appropriate review was made to determine presence or absence of superior mesenteric vessels and portal vein involvement. Final diagnosis was obtained in all cases by surgical explorations. The overall accuracy rate for detecting or excluding superior mesenteric vessels and portal vein involvement was 96% (25 of 26 patients) with CTAP, 88% (23 of 26 patients) with dynamic contrast-enhanced CT, and 85% (22 of 26 patients) with angiography. No statistically significant difference in accuracy was found among the three techniques. Our results suggest that the use of CTAP is not indicated in the preoperative detection of superior mesenteric vessels and portal vein involvement in patients with pancreatic adenocarcinoma.

Mesoinnominate shunt for the treatment of Budd-Chiari syndrome: evaluation with multimodality imaging

The construction of a mesoinnominate shunt between the superior mesenteric vein and the left innominate vein is a recent surgical procedure for the treatment of Budd-Chiari syndrome with vena caval obstruction. The purpose of this study was to determine the role of the different imaging modalities for the follow-up of mesoinnominate shunts. Doppler US (n = 32), and MR imaging examinations (n = 32) were prospectively performed in 10 patients with mesoinnominate shunts. Shunt patency or thrombosis was confirmed with angiography (n = 32) and transhepatic portography with pressure measurement (n = 6). For each follow-up evaluation, all examinations were performed within 4 days. Shunt patency was correctly demonstrated in 28/28 cases with Doppler US, CT and MR imaging. Shunt thrombosis was correctly demonstrated in 4/4 cases with Doppler US, CT and MR imaging. Since Doppler US, CT and MR imaging have the same accuracy for diagnosing mesoinnominate shunt patency and detecting thrombosis, our study suggests that redundant screening methods can be avoided. Doppler US is accurate enough and should be the preferred technique in the evaluation of mesoinnominate shunts.