Kazumitsu Honjo

Therapeutic efficacy of transcatheter arterial chemoembolization for hepatocellular carcinoma: MRI and pathology.

Objective Our goal was to evaluate the usefulness of multisection dynamic MRI with gadopentetate dimeglumine in the assessment of the therapeutic efficacy of transcatheter arterial chemoembolization (TAE) with iodized oil for hepatocellular carcinomas (HCCs). Materials and Methods Findings on multisection dynatnic MR images were compared with gross appearance and histologic findings in 13 patients with HCCs after TAE with iodized oil. Arterial dominant phase images of the entire liver were obtained 20 s after the start of administration of gadopentetate dimeglumine. Results In 3 of the 13 patients, no enhancing areas within the tumors were detected. In the retnaining 10 patients, enhancing portions were detected within the tumor on arterial dominant phase images. Histologically, viable tumor cells were present in the rapidly enhancing portions, while necrotic tissues were present in nonenhancing areas, irrespective of the accumulation of iodized oil on CT scans. However, in one patient in whotn no enhancing portion was seen in the tumor, a small number of viable tumor cells within the capsule were identified on pathologic examination. Conclusion Multisection dynamic MRI is helpful for evaluating the therapeutic efficacy of TAE with iodized oil for HCCs by revealing the hemodynamics of the tumor irrespective of accumulation of iodized oil. Index Terms Liver neoplasms—Contrast media—Magnetic resonance imaging.

Detection of hepatocellular carcinoma: comparison of T2-weighted breath-hold fast spin-echo sequences and high-resolution dynamic MR imaging with a phased-array body coil.

The purpose of our study was to compare T2‐weighted breath‐hold fast spin‐echo sequence (BHFSE) and high‐resolution dynamic MR imaging (HR‐DMRI) in the detection of hepatocellular carcinoma (HCC). Short and long T2‐weighted BHFSE sequences and biphasic HR‐DMRI including arterial‐dominant and delayed phase images with a phased‐array body coil were performed in 30 consecutive patients with 37 HCCs. The lesion‐to‐liver contrast‐to‐noise ratio (CNR) was quantitatively measured. The lesion conspicuity and delineation was qualitatively rated according to a four‐point scale. The lesion‐to‐liver CNR was highest with the arterial‐dominant phase HR‐DMRI and was significantly higher than those obtained with both short and long T2‐weighted BHFSE and those obtained with unenhanced and delayed HR‐DMRI. The CNR obtained with short T2‐weighted BHFSE was significantly higher than those obtained with long T2‐weighted BHFSE and with unenhanced and delayed HR‐DMRI. The sensitivity for the sequences was 78.4% (29/37) for short T2‐weighted BHFSE, 67.6% (25/37) for long T2‐weighted BHFSE, 37.8% (14/37) for unenhanced HR‐DMRI, 97.3% (36/37) for arterial‐dominant phase HR‐DMRI, and 43.2% (16/37) for delayed HR‐DMRI. The sensitivity of serial dynamic MR imaging combined with unenhanced, arterial‐dominant phase imaging and delayed phase imaging was 100% (37/37). The score in the qualitative analysis of the lesion conspicuity and delineation was highest for the arterial‐dominant phase HR‐DMRI and was significantly higher than that for the short T2‐weighted BHFSE. The score for the short T2‐weighted BHFSE was significantly higher than that for the long T2‐weighted BHFSE and that for the unenhanced HR‐DMRI. Arterial‐dominant phase HR‐DMRI is superior to the T2‐weighted BHFSE technique, and also HR‐DMRI combined with unenhanced, arterial‐dominant and delayed phases is the most sensitive technique in the detection of HCC. J. Magn. Reson. Imaging 1999;9:274–279.

Hepatic perfusion abnormalities in acute pancreatitis : CT appearance and clinical importance

Abstract.Background: The purpose of the present study was to describe the computed tomography (CT) appearances of transient hepatic attenuation differences (THADs) in patients with acute pancreatitis and to discuss the mechanism of THAD. Methods: Two-phase dynamic CT images of 28 patients with acute pancreatitis were reviewed. Among them, THAD was seen in nine patients. All patients underwent ultrasonography, and four patients with THAD underwent surgery. Results: Three types of THAD (THAD adjacent to the gallbladder in five of 28 patients, THAD with left lobar distribution in three of 28, wedge-shaped THAD in one of 28) were seen on the two-phase dynamic CT scans of patients with acute pancreatitis. In five patients, THAD disappeared when acute pancreatitis had subsided. Conclusions: THAD in acute pancreatitis is probably caused by increased arterial blood flow attributable to the inflamed lobe of the liver or the inflamed gallbladder. THAD in acute pancreatitis should not be confused with primary liver abnormalities.

Dynamic MR follow-up of small hepatocellular carcinoma after percutaneous ethanol injection therapy.

For patients with small hepatocellular carcinomas (HCCs) treated by percutaneous ethanol injection (PEI) therapy, dynamic MRI has been performed to evaluate the therapeutic efficacy at our institute. In this pictorial essay, we illustrate the various dynamic MR findings of HCCs after PEI therapy, including complete necrosis, partial necrosis, local recurrence, and pathologic conditions such as arterioportal shunt and contractive changes of hepatic parenchyma. We also present the limitation of dynamic MRI in the evaluation of therapeutic effectiveness of PEI therapy.

Differential diagnosis of hepatic tumors with delayed enhancement at gadolinium- enhanced mri: a pictorial essay

Hepatic lesions with delayed enhancement are sometimes encountered on gadolinium-enhanced MRI of the liver. This study illustrates the varied appearances of several pathologic entities with delayed enhancement, including hepatic hemangioma, hepatic metastases, intrahepatic cholangiocarcinoma, focal nodular hyperplasia, hepatic abscess, hepatocellular carcinoma, and hepatocellular carcinoma after transcatheter arterial chemoembolization, and presents the utility of arterial-phase dynamic MRI in the differential diagnosis of these lesions. Possible causes of these delayed enhancements are also discussed.

Distinction of hemangiomas from hepatic tumors with delayed enhancement by incremental dynamic CT

To analyze the patterns of contrast enhancement and to evaluate clinical utility, we performed table incremental dynamic CT in 21 patients with 30 hepatic hemangiomas and in 12 patients with 26 malignant neoplasms, which showed delayed enhancement. On incremental CT, dense, spotty peripheral enhancement was present in 23 of the 30 (77%) hemangiomas. In contrast, a circumferential bead- or bank-like peripheral enhancement was seen in 19 of 26 (73%) malignant neoplasms. The findings were characteristic. We conclude that incremental CT is useful in the differential diagnosis of hepatic hemangioma in routine examination.

Hepatic parenchymal enhancement in the cirrhotic liver: evaluation by triple-phase dynamic MRI

AbstractBackground: To evaluate the changes of liver parenchymal enhancement in the cirrhotic liver by means of triple-phase dynamic magnetic resonance (MR) imaging. Methods: Triple-phase multisection dynamic MR imaging was performed in 32 patients with liver cirrhosis. The control group consisted of 19 patients without liver cirrhosis. After precontrast images were obtained, arterial phase images were acquired 20 s after the start of intravenous bolus administration of 0.10 mmol/kg of gadopentetate dimeglumine. Portal and delayed phase images were then acquired 1 and 3 min, respectively, after the injection of contrast material. On each phase image, the signal-to-noise ratio (S/N) from the liver parenchyma was measured by operator-defined regions of interest (ROIs). The contrast-enhanced ratio (CER) on each phase was then obtained according to the following formula: [S/N(arterial or portal or delayed phase image) − S/N(precontrast image)]÷ S/N(precontrast image). The portal perfusion index (PPI) also was obtained according to the following formula: [S/N(portal phase image − S/N(arterial phase image)]÷ S/N(arterial phase image). The results were expressed as mean ± SD. Results: The CERs of arterial, portal, and delayed phase images in patients with and without liver cirrhosis were 0.256 ± 0.211, 0.640 ± 0.384, and 0.554 ± 0.318 and 0.132 ± 0.094, 0.404 ± 0.204, and 0.324 ± 0.144, respectively. The CERs were highest in the portal phase and lowest in the arterial phase in patients with and without liver cirrhosis. The CER of the cirrhotic liver was significantly higher than that of the normal liver in every phase (p < 0.05). PPIs with and without liver cirrhosis were 2.90 ± 4.03 and 3.86 ± 3.89, respectively. The PPI with liver cirrhosis was significantly lower than that without liver cirrhosis (p < 0.05). Conclusion: The enhancement of cirrhotic liver parenchyma is greater than that of the normal liver parenchyma at every phase of triple-phase dynamic MR imaging.

Chromosome spreading techniques for primary gastrointestinal tumors

The requirement for well spread out chromosomes for the cytogenetic analysis of primary gastrointestinal tumors led us to develop new techniques. These techniques involved two main procedures: (1) preliminary incubation with culture medium in the presence of collagenase, Dispase, and colcemid, for 3h, and (2) treatment with an extremely hypotonic solution (0.044 M KCl) for 30 min. The techniques were applied to 11 gastrointestinal malignancies (including 1 early gastric cancer and 1 metastatic liver lesion of colon cancer) and significant increases (P<0.01) in the number of metaphases of analyzable karyotypes were obtained, compared with a previous method in which the standard hypotonic molarity of KCL (0.075 M) was employed. The mean value for metaphase numbers of the analyzable karyotypes was 37.0±3.7% in the 5 gastric cancers and 44.7±4.8% in the 5 colon cancers and 1 metastatic lesion. These values were three times and more than twice, respectively, the values obtained by the previous method. A fluorescence in situ hybridization (FISH) study was carried out on one cologenic tumor, the α-satellite centromere-specific probe 17 being used. Deletion of the long arm of chromosome 17 was demonstrated. The method proposed here could yield a sufficient number of metaphases without the use of tissue culture that might cause alteration of karyotype. It can be employed with small biopsy specimens and in studies utilizing the FISH technique.

Inferior phrenic arteries: depiction with thin-section three-dimensional contrast-enhanced dynamic MR imaging with fat suppression.

The purpose of this study was to evaluate visibility of the inferior phrenic arteries in normal subjects at thin‐section, multiphasic, three‐dimensional (3D) contrast‐enhanced dynamic magnetic resonance (MR) imaging with fat suppression, and to compare the appearances and frequencies of MR visualization of these vessels between normal and cirrhotic patients. This study included 95 patients (44 normal and 51 cirrhotic patients) who underwent 3D contrast‐enhanced dynamic imaging on a high‐performance gradient (25 mT/m) system as a part of abdominal MR examinations. The right and left inferior phrenic arteries were visible in 84% and 73% of the normal subjects, respectively. The averaged rating for visibility in the right inferior phrenic artery was significantly greater in the cirrhotic patients than in the normal subjects (2.1 ± 0.1 vs. 1.7 ± 0.2; P = 0.040). Mean diameters of the right inferior phrenic artery in the cirrhotic patients (1.7 ± 0.1 mm) were significantly larger (P = 0.002) than those in the normal subjects (1.3 ± 0.1 mm). No significant difference was noted in the mean diameters and the visibility of the left inferior phrenic artery between the two groups. The inferior phrenic arteries can frequently be identified on thin‐section, 3D contrast‐enhanced arterial‐phase dynamic MR images with fat‐suppression techniques. Dilatation of the right inferior phrenic artery depicted by this technique may be a nonspecific but an additional secondary finding suggestive of cirrhosis. J. Magn. Reson. Imaging 2001;13:201–206.

Homogeneous enhancement of hepatic parenchyma: MR imaging during arterial portography versus CT during arterial portography

AbstractBackground: The goal of this study was to investigate the frequency of inhomogeneous parenchymal enhancement of the liver in magnetic resonance imaging during arterial portography (MRAP) versus computed tomography during arterial portography (CTAP). Methods: CTAP and MRAP were performed in 29 and in 21 patients, respectively, who had suspected primary or secondary liver tumors on clinical or biological grounds. We evaluated the frequency of inhomogeneous hepatic parenchymal enhancement not related to a decrease of portal blood supply due to compression or obstruction by the tumor and physiologic variation in portal perfusion. Inhomogeneous parenchymal enhancement of the liver was classified as segmental or subsegmental and as nonsegmental. Results: Segmental or subsegmental inhomogeneous parenchymal enhancement was seen in six of 29 patients (20.1%) on CTAP and in one of 21 patients (4.8%) on MRAP. Nonsegmental inhomogeneous parenchymal enhancement was seen in five of 29 patients (17.2%) on CTAP images and in none of the patients (0%) on MRAP images. The incidence of nonsegmental inhomogeneous parenchymal enhancement was significantly lower on MRAP than on CTAP. Conclusion: MRAP was superior to CTAP in achieving homogeneous parenchymal enhancement of the liver.