Biomedical subjects

Hitoshi Aibe

Publications and source records attributed to Hitoshi Aibe.

24 records · Page 2Linked to original sources

PubMedDate not supplied

MR imaging of ampullary carcinomas.

OBJECTIVE: The purpose of this study was to demonstrate the appearance of ampullary carcinomas on MR images. METHODS: Sixteen patients with ampullary carcinomas underwent MR imaging. Tumor detectability, signal intensity of the tumor, and enhancement pattern on dynamic study were analyzed. MR cholangiopancreatography (MRCP) findings were assessed and were compared with the endoscopic retrograde cholangiopancreatography (ERCP) findings. RESULTS: Signal intensities of the tumor on each image were various. Dynamic study detected all tumors except one, and all detected tumors showed delayed enhancement. MRCP delineated more than half of the tumors as a filling defect within the duodenal fluid and clearly demonstrated pancreaticobiliary ductal. CONCLUSIONS: Dynamic study is mandatory in diagnosing ampullary carcinoma, because it can depict most of the tumors, and delayed enhancement of such tumors is characteristic in case of ampullary carcinoma. MRCP can provide reliable information about pancreaticobiliary duct and it can replace diagnostic ERCP.

Aged↗

PubMedDate not supplied

Fitz-Hugh-Curtis syndrome. Radiologic manifestation.

OBJECTIVES: To clarify radiologic findings of Fitz-Hugh-Curtis syndrome (FHCS). METHODS: Thirteen women with right upper abdominal pain who were clinically diagnosed with FHCS were included. Biphasic helical computed tomography (CT) of the abdomen was performed in all patients. Posttherapeutic follow-up CT was available in 7 patients. Ultrasonography (US) was also performed in 12 patients. These imaging findings were reviewed retrospectively. RESULTS: On enhanced CT, hepatic and splenic capsular enhancement was identified in 13 and 4 patients, respectively. Hepatic capsular enhancement on the early phase, which was detected in all patients, disappeared after treatment. No adhesive band or fluid collection around the liver was evident. No enhancement of the "bare area" of the liver and spleen was seen. No definite abnormality of the liver or perihepatic region was detected by US. CONCLUSIONS: Hepatic and splenic capsular enhancement on abdominal enhanced CT may be characteristic of FHCS. Enhanced CT may be a useful and noninvasive modality to help a diagnosis of FHCS, especially in young women with right upper abdominal pain without significant findings on US and gastrointestinal endoscopy.

Abdominal Pain↗

PubMedDate not supplied

Natural history of pancreatic intraductal papillary mucinous tumor of branch duct type: follow-up study by magnetic resonance cholangiopancreatography.

OBJECTIVE: The purpose of this study was to elucidate the natural history of branch duct type pancreatic intraductal papillary mucinous tumor (IPMT) by evaluating serial changes in the magnetic resonance cholangiopancreatography (MRCP) findings of patients diagnosed with pancreatic IPMT of branch duct type. METHODS: Thirty-five patients had branch duct type IPMT, including 9 patients with separate lesions, and underwent initial and follow-up MRCP over a period of more than 12 months. The maximum diameter of the cystic lesion, the presence of associated main pancreatic duct (MPD) dilatation, and the presence of a filling defect were evaluated. Serial changes in these findings were analyzed. RESULTS: Tumor enlargement on follow-up MRCP was observed in 7 cases. Of the 29 branch duct IPMTs without associated MPD dilatation or a filling defect identified on initial MRCP, only 1 showed gradual tumor enlargement. In 4 cases, the cyst size decreased on follow-up MRCP. CONCLUSIONS: Branch duct type IPMTs grow slowly and can be monitored without operation provided that the tumor shows no associated MPD dilatation or filling defect.

Aged↗

PubMedDate not supplied

Comparison of test-injection method and fixed-time method for depiction of hepatocellular carcinoma using dynamic steady-state free precession magnetic resonance imaging.

OBJECTIVE: The purpose of this study was to clarify the usefulness of the test-injection method as compared with the fixed-time method in dynamic magnetic resonance (MR) imaging of hepatocellular carcinoma (HCC). METHODS: Ninety-seven patients with a total of 118 hepatocellular carcinomas underwent 3-dimensional fast imaging with steady-state free precession (3D-FISP) for dynamic study of the liver as well as catheter-assisted computed tomography hepatic angiography (CTHA) for preoperative evaluation. In 42 cases, the fixed-time method (30-second scan time delay in the hepatic arterial phase [HAP]) was performed (group 1), and in 55 cases, the test-injection method was performed (group 2). The following parameters were evaluated: 1) the adequacy of the HAP, 2) tumor vascularity using CTHA findings as a gold standard, and 3) the contrast-to-noise ratio (CNR) of the HCC during the HAP of dynamic MR imaging. RESULTS: In group 1, 79% (33 of 42) of the cases were obtained at the optimal HAP; the percentage in group 2 was 98% (54 of 55) of the cases. This difference was statistically significant (P < 0.05). The vascularity of 82% of the tumors in group 1 and 89% of those in group 2 was diagnosed correctly. Regarding hypervascular tumors, correct evaluation of tumor vascularity was made in 87% of group 1 cases and 95% of group 2 cases. No significant difference was present between the 2 groups (total: P = 0.43, hypervascular HCC: P = 0.29). 3) The CNR calculated for all HCCs in group 2 (mean +/- SD: 8.66 +/- 11.0) was significantly higher than that for HCCs in group 1 (4.29 +/- 9.44; P < 0.05). As for the hypervascular tumors, the CNR calculated for group 2 (mean +/- SD: 9.89 +/- 10.6) was also significantly higher than that for group 1 (5.52 +/- 9.81; P < 0.05). CONCLUSION: The 3D-FISP dynamic MR imaging using the test-injection method resulted in better demonstration of HCC than the 3D-FISP using the fixed-time method.

Adult↗

PubMedDate not supplied

Detecting postsurgical recurrent hepatocellular carcinoma with multiphasic helical computed tomography: intrahepatic metastasis or multicentric occurrence?

OBJECTIVE: The aim of this study was to assess the computed tomography (CT) patterns of postoperative recurrent hepatocellular carcinoma (HCC). METHODS: Of 84 patients with histologically proven HCC by hepatectomies, multiphasic helical CT demonstrated 54 HCC lesions of intrahepatic recurrence in 31 (37%) patients. The initial and final appearances of HCC on hepatic arterial phase images were retrospectively determined by the serial CT scans, which were compared with appearances of primary HCC. RESULTS: The initial appearances of 54 recurrent HCCs were identical to the appearances of primary HCC in 41 (76%) lesions. Serial changes from the initial appearance to the final appearance of recurrent HCC were observed in 10 (42%) of 24 lesions. The 13 discordant lesions and the 10 lesions with altered lesion vascularity in our series implied that at least 43% were of multicentric occurrence. CONCLUSION: More than 40% of postoperative recurrent HCCs show intranodular hemodynamic changes. The incompatibility between CT findings of primary and recurrent HCCs implies that these tumors contain nodules of multicentric occurrence.

Adult↗

PubMedDate not supplied

Optimal multi-phase three-dimensional fast imaging with steady-state free precession dynamic MRI and its clinical application to the diagnosis of hepatocellular carcinoma.

PURPOSE: To determine the appropriate acquisition parameters for three-dimensional fast imaging with steady-state free precession (3D-FISP), to clarify the superiority of 3D-FISP to two-dimensional fast low-angle shot (2D-FLASH) on phantom study, and to clarify the clinical usefulness of 3D-FISP in diagnosing hepatocellular carcinoma (HCC). MATERIALS AND METHODS: 3D-FISP images with varying flip angles were compared by using a phantom. Signal-to-noise ratios (SNRs) and contrast-enhancement ratios (CERs) were compared for the four two-dimensional fast low-angle shot (2D-FLASH) sequences and 3D-FISP sequences in a phantom. The optimal 3D-FISP dynamic study was compared with plain, postcontrast MR sequences used to study 78 HCC cases and analyzed according to histological grade. The 3D-FISP image obtained 30 sec after gadopentetate dimeglumine (Gd) administration was also compared with CT hepatic angiography (CTHA). RESULTS: A 25 degrees flip angle and double-dose Gd administration were appropriate for 3D-FISP dynamic study. CER was the highest with 3D-FISP, and SNR was higher in 3D-FISP than in 2D-FLASH images in a phantom with high Gd concentration. Among the 105 lesions, 103 (98%) were depicted on 3D-FISP images. The detection rate of HCC on 3D-FISP was higher than 95% for each histological grade. The vascularity of the tumors as determined by CTHA findings was correctly diagnosed on 3D-FISP in 80% of cases. CONCLUSION: In phantom study, 3D-FISP with double-dose Gd injection showed higher contrast than 2D-FLASH as a sequence for liver dynamic study. In clinical study, 3D-FISP is useful in the detection of HCC, regardless of tumor vascularity and histological grade.

Carcinoma, Hepatocellular↗