Differentiation between hepatic cavernous hemangioma and malignant tumor with T2-weighted MRI: comparison of fast spin-echo and breathhold fast spin-echo pulse sequences.

PURPOSE: The goal of our study was to compare a T2-weighted breathhold fast spin-echo (BHFSE) technique with T2-weighted nonbreathhold fast spin-echo (FSE) technique for characterizing cavernous hemangioma of the liver and differentiating this entity from malignant tumor. MATERIALS AND METHODS: Eighteen patients with cavernous hemangiomas and 18 patients with malignant hepatic tumors were studied with T2-weighted MRI with a nonbreathhold FSE technique with and without fat suppression and with a BHFSE technique without fat suppression. Hepatic lesions were analyzed quantitatively using signal intensity (SI) and contrast-to-noise (C/N) ratio. In addition, images were qualitatively compared for accuracy in characterizing hepatic lesion. RESULTS: Quantitatively, hemangioma had significantly higher SI and C/N ratios than did the malignant tumor on every pulse sequence (P < 0.01). Qualitatively, all malignant tumors were correctly categorized; differentiation between cavernous hemangioma and malignant tumor was impossible in three cases of cavernous hemangioma with the three pulse sequences (92% accuracy, 100% sensitivity, and 83% specificity). CONCLUSION: T2-weighted FSE and BHFSE MRI shows comparable levels of accuracy for differentiating between hepatic cavernous hemangioma and malignant tumor. Because overlap may exist using quantitative measurement, morphologic patterns must be carefully analyzed, supporting that quantitative analysis and morphologic evaluation are complementary.

T1-weighted spoiled gradient-echo MR imaging of focal hepatic lesion: comparison of in-phase vs opposed-phase pulse sequence.

The goal of our prospective study was to compare quantitatively and qualitatively in-phase and opposed-phase T1-weighted breath-hold spoiled gradient-recalled-echo (GRE) MR imaging technique for imaging focal hepatic lesion. Thirty-eight patients with 53 focal hepatic lesions had in-phase (TR = 12.3 ms, TE = 4.2 ms) and opposed-phase (TR = 10.1 ms, TE = 1.9 ms) GRE (flip angle = 30 degrees , bandwidth +/- 32 kHz, matrix size 256 x 128, one signal average) MR imaging at 1.5 T. Images were analyzed quantitatively by measuring the lesion-to-liver contrast and for lesion detection. In addition, images were reviewed qualitatively for lesion conspicuity. Quantitatively, lesion-to-liver contrast obtained with in-phase (3. 22 +/- 1.86) and opposed-phase pulse sequence (3.72 +/- 2.32) were not statistically different (Student's t-test). No difference in sensitivity was found between in-phase and opposed-phase pulse sequence (31 of 53, sensitivity 58 % vs 30 of 53, sensitivity 57 %, respectively). Two lesions not seen with opposed-phase imaging were detected with in-phase imaging. Conversely, one lesion not seen on in-phase imaging was detected on opposed-phase imaging so that the combination of in-phase and opposed-phase imaging yielded detection of 32 of 53 lesions (sensitivity 60 %). Qualitatively, lesion conspicuity was similar with both techniques. However, in-phase images showed better lesion conspicuity than opposed-phase images in 9 cases, and opposed-phase images showed better lesion conspicuity than in-phase images in 7 cases. No definite advantage (at a significant level) emerged between in-phase and opposed-phase spoiled GRE imaging. Because differences in lesion conspicuity and lesion detection may be observed with the two techniques in individual cases, MR evaluation of patients with focal hepatic lesion should include both in-phase and opposed-phase spoiled GRE imaging.

Hepatic cavernous hemangioma: appearance on T2-weighted fast spin-echo MR imaging with and without fat suppression.

OBJECTIVE: The goals of our study were to define the morphologic appearance of cavernous hemangioma of the liver on T2-weighted fast spin-echo MR imaging and to determine if the use of fat suppression may quantitatively and qualitatively modify the MR imaging appearance of cavernous hemangioma. SUBJECTS AND METHODS: Twenty-six patients with cavernous hemangiomas of the liver were prospectively studied with T2-weighted MR imaging with a fast spin-echo technique with and without fat suppression. Thirteen patients had known hemangiomas for more than 2 years, with no change in size or morphology during this period. The remaining 13 patients had diagnoses based on dynamic CT and sonography and an absence of change in the morphology and size of their lesions during follow-up of more than 6 months (range, 6-12 months) after the MR imaging studies. Values for signal intensity and contrast-to-noise (C/N) ratios in cavernous hemangiomas that were obtained with and without fat suppression were compared. Images were qualitatively analyzed separately at identical level and window settings by two interpreters for morphologic features of cavernous hemangiomas. RESULTS: No significant difference was found between signal intensity values obtained using the fat-suppressed fast spin-echo MR imaging technique (5.62 +/- 1.14 [SD]) and those obtained without fat suppression (5.51 +/- 1.23). Values for C/N ratios obtained with the fat-suppressed fast spin-echo MR imaging technique (20.13 +/- 7.63) were significantly superior to those obtained without fat suppression (16.59 +/- 5.31) (p < .001). On T2-weighted fast spin-echo MR imaging without fat suppression, 100% of cavernous hemangiomas were hyperintense relative to the spleen, 90% had well-defined and sharp margins, 55% were isointense to CSF, and 76% were homogeneous. Without fat suppression, 34% of cavernous hemangiomas showed the combination of isointensity to CSF, well-defined margins, and homogeneity. On T2-weighted fast spin-echo MR imaging with fat suppression, all cavernous hemangiomas showed this same combination of features. CONCLUSION: Seventy-six percent of hepatic cavernous hemangiomas were homogeneous on T2-weighted fast spin-echo MR imaging, and 55% were isointense to CSF. However, only 34% of hepatic cavernous hemangiomas showed typical features. Although fat suppression significantly increased the C/N ratio of cavernous hemangiomas of the liver, fat suppression did not affect their morphologic appearance on T2-weighted fast spin-echo MR imaging.

MR imaging of the liver: effect of portal hypertension on hepatic parenchymal enhancement using a gadolinium chelate.

The purpose of this study was to prospectively investigate the extent to which reduced portal blood flow in patients with hepatic cirrhosis and portal hypertension affects hepatic parenchymal enhancement during gadolinium-chelate-enhanced dynamic MR imaging. Breath-hold three-dimensional (3D) spoiled gradient-recalled echo (GRE) MR imaging technique obtained after intravenous administration of a gadolinium chelate was used to measure hepatic parenchymal enhancement and time to peak enhancement in 20 patients with hepatic cirrhosis and clinical evidence of portal hypertension (group 1) and in 20 control subjects without portal hypertension (group 2) who were matched for age, sex, and body weight. Mean peak hepatic enhancement values +/- SD and times to peak enhancement +/- SD were determined for both groups of patients. Mean peak enhancement value (+/-SD) was 78.7% +/- 36.2 in group 1 and 91.6% +/- 46.2 in group 2 (not significant). However, in the nine patients in group 1 with splenomegaly, mean peak enhancement value was 61.3% +/- 14.4, whereas it was 93.0% +/- 42.7 in the 11 patients without splenomegaly (P < .05). Mean time to peak enhancement was 84 seconds +/- 23 in group 1 and 54.0 sec +/- 25.0 in group 2 (P < .01). Our results show that mean peak enhancement value of hepatic parenchyma after intravenous administration of a gadolinium chelate is significantly altered for patients with portal hypertension and splenomegaly. In addition, the time to peak enhancement is delayed significantly when portal hypertension is present. Thus, it is possible that the optimal time for imaging the liver during the portal phase must be tailored to the status of the portal system of the patient.

Focal nodular hyperplasia of the liver: assessment of hemodynamic and angioarchitectural patterns with gadolinium chelate-enhanced 3D spoiled gradient-recalled MRI and maximum intensity projection reformatted images.

PURPOSE: Our goal was to determine the relative merits of gadolinium chelate-enhanced 3D spoiled gradient-recalled (GRE) MRI versus maximum intensity projection (MIP) reformatted images in assessing the morphologic, hemodynamic, and angioarchitectural patterns of focal nodular hyperplasia (FNH) of the liver. METHOD: Ten consecutive patients with 10 FNHs had prospectively gadolinium chelate-enhanced 3D spoiled GRE MRI (TR/TE/FA = 10.1/1.9/30) of the liver at 1.5 T. Gadolinium chelate-enhanced 3D spoiled GRE source images and MIP reformatted images were separately analyzed with respect to morphologic and hemodynamic features and angioarchitectural patterns by two independent readers. RESULTS: Gadolinium chelate-enhanced 3D spoiled GRE source images and MIP reformatted images showed the most intense degrees of enhancement of FNH during the arterial phase of hepatic parenchymal enhancement in all cases. Gadolinium chelate-enhanced 3D spoiled GRE source images were superior to MIP reformatted images for the assessment of morphologic features of FNH (p < 0.02). MIP reformatted images were superior to the corresponding source images for showing the main branches of the hepatic artery, an arterial branch going to the FNH, and a small artery within the FNH radiating to peripheral areas (p < 0.05). There was excellent agreement between the two observers for analysis of the MIP reformatted images (p < 0.05). CONCLUSION: The combination of gadolinium chelate-enhanced 3D spoiled GRE source images and MIP reformatted images allows the analysis of morphologic, hemodynamic, and angioarchitectural patterns of FNH of the liver. Further study and comparison with currently applied strategies will determine the value of these two techniques for diagnosing FNH of the liver.

Hepatic pseudolesion around the falciform ligament: prevalence on CT examination.

BACKGROUND: The purpose of this study was to determine the prevalence of hepatic pseudolesions seen around the falciform ligament on computed tomography (CT) of the abdomen obtained with intravenous administration of contrast material. METHODS: We first retrospectively reviewed the CT scans of six patients in whom hepatic pseudolesions were seen around the falciform ligament. The abdominal CT scans of 587 patients were then prospectively analyzed for the presence of hepatic pseudolesions around the falciform ligament to determine the prevalence of this finding on CT examinations. RESULTS: CT scans in the first six patients showed two types of hepatic pseudolesion around the falciform ligament. In three patients, hepatic pseudolesions were focal spared areas in fatty liver. In three patients, hepatic pseudolesions were developed in nonfatty liver. Prospectively, hepatic pseudolesions were found on five of 587 CT examinations (prevalence = 1%). A single hepatic pseudolesion was found in segment 4 on two examinations. Two hepatic pseudolesions (one in segment 4 and one in segment 3) were found together on three CT examinations. CONCLUSION: Hepatic pseudolesions around the falciform ligament are seldom seen on CT scan. However, recognition of these pseudolesions is crucial because they may be interpreted as true tumors.

Detection of focal hepatic lesions with MR imaging: prospective comparison of T2-weighted fast spin-echo with and without fat suppression, T2-weighted breath-hold fast spin-echo, and gadolinium chelate-enhanced 3D gradient-recalled imaging.

OBJECTIVE: The purpose of this study was to compare breath-hold three-dimensional (3D) rapid gradient-echo (GRE) MR imaging obtained before and after gadolinium chelate injection with T2-weighted fast spin-echo and T2-weighted breath-hold fast spin-echo (BHFSE) MR imaging in the detection of focal hepatic masses. SUBJECTS AND METHODS: Fifty-three patients with 108 focal hepatic masses had, prospectively, MR of the liver at 1.5 T. T2-weighted fast spin-echo (6000/117 [TR/effective TE]; echo train length=16; acquisition time = 3 min 12 sec) images obtained with and without fat suppression, T2-weighted BHFSE (2700/105; echo train length = 20; acquisition time = 22 sec), and 3D rapid GRE images (10.1/1.9/30 degrees [TR/TE/alpha]) obtained during one breath-hold (12 scan locations in 21 sec or 20 scan locations in 32 sec) before and after injection of gadolinium chelate were blindly and independently analyzed in consensus by three readers. RESULTS: Gadolinium chelate-enhanced 3D rapid GRE images allowed depiction of more focal hepatic masses (90 of 108, sensitivity = 83%) than did T2-weighted fast spin-echo with fat suppression images (76 of 108, sensitivity = 70%), T2-weighted fast spin-echo without fat suppression images (74 of 108, sensitivity = 69%), T2-weighted BHFSE images (73 of 108, sensitivity = 68%), and unenhanced 3D rapid GRE images (54 of 108, sensitivity = 50%) (p < .01). No difference in sensitivity was found between the three T2-weighted sequences. CONCLUSION: Gadolinium chelate-enhanced 3D rapid GRE imaging is superior to T2-weighted fast spin-echo images obtained with or without fat suppression for the detection of focal hepatic masses. T2-weighted BHFSE is similar to T2-weighted fast spin-echo images in detecting focal hepatic lesions.

T2-weighted spin-echo MR imaging of the liver: breath-hold fast spin-echo versus non-breath-hold fast spin-echo images with and without fat suppression.

OBJECTIVE: The goal of our study was to compare a T2-weighted breath-hold fast spin-echo (BHSE) technique with T2-weighted non-breath-hold fast spin-echo techniques for imaging the liver. SUBJECTS AND METHODS: Thirty-three patients with hepatic lesions had T2-weighted BHSE images obtained in 22 sec and conventional T2-weighted non-breath-hold fast spin-echo images obtained in 3 min 12 sec with and without fat suppression. Images were analyzed quantitatively by measuring the lesion-liver contrast, spleen-liver contrast, and signal-to-noise ratios of lesions and qualitatively by evaluating the sharpness of hepatic contours, visibility of intrahepatic vessels and other segmental landmarks, and presence of artifacts. RESULTS: Quantitatively, lesion-liver contrast, spleen-liver contrast, and signal-to-noise ratios obtained with the BHSE technique were inferior to those obtained with fast spin-echo techniques with and without fat suppression (11.2 +/- 7.1 versus 15.4 +/- 10.6 and 14.5 +/- 9.8, p < .001; 5.3 +/- 3.7 versus 8.7 +/- 3.5 and 7.0 +/- 3.8, p < .001; 16.2 +/- 8.2 versus 20.1 +/- 10.9 and 19.7 +/- 9.5, p < .01, respectively; Student's t test). Qualitatively, image artifacts and intrahepatic vessel depiction on BHSE images were similar to those obtained with the fast spin-echo techniques. The BHSE technique was superior to fat-suppressed fast spin-echo technique for showing hepatic contours (p < .01; Wilcoxon signed-rank test). CONCLUSION: The BHSE technique is quantitatively inferior to non-breath-hold fast spin-echo techniques. However, further studies with a surgical standard of reference are needed to compare the three techniques in terms of sensitivity.

MR diagnosis of hepatic metastases from neuroendocrine tumors versus hemangiomas: relative merits of dynamic gadolinium chelate-enhanced gradient-recalled echo and unenhanced spin-echo images.

OBJECTIVE: Hepatic metastases from neuroendocrine tumors are often markedly hyperintense on unenhanced T2-weighted MR images, making their appearance similar to that of cavernous hemangiomas. In contrast, cavernous hemangiomas show characteristic enhancement on dynamic gadolinium chelate-enhanced gradient-recalled echo MR images. The purpose of this study was to determine the relative merits of dynamic gadolinium chelate-enhanced gradient-recalled echo MR imaging versus MR imaging with unenhanced spin-echo pulse sequences for distinguishing between hepatic metastases from neuroendocrine tumors and cavernous hemangiomas. MATERIALS AND METHODS: The unenhanced spin-echo and dynamic gradient-recalled echo MR images obtained after IV administration of a gadolinium chelate in 28 patients (14 patients with pathologically proven hepatic metastases from neuroendocrine tumors and 14 patients with hepatic cavernous hemangiomas) were reviewed blindly and independently by three interpreters. Unenhanced spin-echo and dynamic gadolinium chelate-enhanced gradient-recalled echo MR images were compared for accuracy in characterizing liver lesions. RESULTS: The most intense enhancement of hepatic metastases from neuroendocrine tumors was observed on early dynamic gadolinium chelate-enhanced gradient-recalled echo MR images; enhancement was peripheral in four patients, global and heterogeneous in seven patients, and global and homogeneous in three patients. On late dynamic gadolinium chelate-enhanced gradient-recalled echo MR images, enhancement of hepatic metastases from neuroendocrine tumors was predominantly peripheral in five patients, global and heterogeneous in five patients, and global and homogeneous in four patients. Differentiation between cavernous hemangiomas and hepatic metastases from neuroendocrine tumors was impossible in five cases with unenhanced spin-echo MR imaging alone, in five cases with dynamic gadolinium chelate-enhanced gradient-recalled echo MR imaging alone, and in no case with the combination of unenhanced spin-echo MR imaging and dynamic gadolinium chelate-enhanced gradient-recalled echo MR imaging. In comparison with unenhanced spin-echo MR imaging alone or dynamic gadolinium chelate-enhanced gradient-recalled echo MR imaging alone, the combination of unenhanced spin-echo MR imaging and dynamic gadolinium chelate-enhanced gradient-recalled echo MR imaging allowed significantly (p < .001) clearer differentiation between hepatic metastases from neuroendocrine tumors and cavernous hemangiomas. CONCLUSIONS: Early enhancement and heterogeneity on dynamic gadolinium chelate-enhanced gradient-recalled echo MR images are the most common features of hepatic metastases from neuroendocrine tumors. The combination of unenhanced spin-echo and dynamic gadolinium chelate-enhanced gradient-recalled echo MR images allows more accurate characterization of hepatic metastases from neuroendocrine tumors and clearer differentiation from cavernous hemangiomas.

[Diagnosis of glucagonoma. Value of scanning, echography and arteriography. Apropos of 2 cases and a review of the literature]. / Diagnostic du glucagonome. Intérêt du scanner, de l'échographie et de l'artériographie. A propos de deux observations et revue de la littérature.

The authors report two cases of glucagonoma, a rare endocrine tumor of the pancreas, and describe the data currently found in literature. Glucagonoma is a single and usually large tumor, which develops in the alpha cells of the islets of Langerhans and evolves slowly. The combination of characteristic skin lesions, diabetes and weight loss should lead to searching for hyperglucagonemia and for the pancreatic tumor. The diagnosis is usually made rather late, average evolution is five years before diagnosis when it is detected. Imaging, in particular ultrasound and computed tomography (CT), proves to be necessary for the positive diagnosis of glucagonoma as it localizes the pancreatic mass and plays a role in local assessment, thus providing guidance for surgery. The role of imaging is also fundamental for the detection of metastases, which are the only sign of malignancy as no criterion of benignity is found for this tumor.