Diffusion-weighed MR imaging of pancreatic carcinoma.

PURPOSE: The aim of this study was to demonstrate the feasibility of body diffusion-weighted (DW) MR imaging in the evaluation of a pancreatic carcinoma. MATERIAL AND METHODS: In nine normal volunteers and in eight patients with pancreatic carcinoma, DW images were obtained on the axial plane scanning with a multisection spin-echo-type single-shot echo planar sequence with a body coil. Moreover, we measured the apparent diffusion coefficient (ADC) value in a circular region of interest (ROI) within the normal pancreas, pancreatic carcinoma, and tumor-associated chronic pancreatitis. RESULTS: On the DW images, all eight carcinomas were clearly shown as high signal intensity relative to the surrounding tissue. The ADC value (x10(-3) mm(2)/s) in the carcinoma was 1.44 +/- 0.20, which was significantly lower compared to that of normal pancreas (1.90 +/- 0.06) and tumor-associated chronic pancreatitis (2.31 +/- 0.18). CONCLUSION: Diffusion-weighted (DW) images can be helpful in detecting the pancreatic carcinoma and accessing the extent of the tumor.

Usefulness of saline pushing in reduction of contrast material dose in abdominal CT: evaluation of time-density curve for the aorta, portal vein and liver.

The effects of saline pushing after contrast material injection were investigated as well as the possibility for this technique to reduce contrast material doses in liver CT examinations. 52 patients were divided randomly into three groups: 100 ml of contrast material (300 mg I ml(-1)) only (A; n = 19), 100 ml of contrast material pushed with 50 ml of saline solution (B; n = 17), and 85 ml of contrast material pushed with 50 ml of saline solution (C; n = 16). Single-level images were obtained at the level of the main portal vein after the initiation of contrast material injection. There were no significant differences in the mean peak enhancement values (PE) and the mean time to peak enhancement values (TPE) of the aorta between the three groups. The mean PE of the portal vein in group B increased 21 HU over that in group A (p<0.05), and there was no significant difference between groups A and C. The mean PE of the liver in group B increased 7 HU over that in group A (p<0.05), and there was no significant difference between groups A and C. The mean TPE of the portal vein was shorter by 4 s (p<0.05), and that of the liver was shorter by 5 s (p<0.05) in group C compared with those in group A. In conclusion, saline pushing increases the enhancement values of the portal vein and liver, and allows a contrast material dose reduction of 15 ml without decreasing hepatic and vascular enhancement at adequate scan timing.

Effect of saline pushing after contrast material injection in abdominal multidetector computed tomography with the use of different iodine concentrations.

PURPOSE: To investigate whether saline pushing after contrast material improves hepatic vascular and parenchymal enhancement, and to determine whether this technique permits decreased contrast material concentration. MATERIAL AND METHODS: 120 patients who underwent hepatic multidetector computed tomography were divided randomly into four groups (Groups A-D): receiving 100 ml of contrast material (300 mgI/ml) only (A) or with 50 ml of saline solution (B); or 100 ml of contrast material (350 mgI/ml) only (C) or with 50 ml of saline solution (D). Computed tomography (CT) values of the aorta in the arterial phase, the portal vein in the portal venous inflow phase, and the liver in the hepatic phase were measured. Visualization of the hepatic artery and the portal vein by 3D CT angiography was evaluated as well. RESULTS: Although the enhancement values of the aorta were not improved significantly with saline pushing, they continued at a high level to the latter slices with saline pushing. The enhancement value of the portal vein increased significantly and CT portography was improved with saline pushing. The enhancement value of the liver was not improved significantly using saline pushing. In a comparison between groups B and C, the enhancement values of the aorta and portal vein and the visualization of CT arteriography and portography were not statistically different. CONCLUSION: The saline pushing technique can contribute to a decrease in contrast material concentration for 3D CT arteriography and portography.

Virtual CT colectomy by three-dimensional imaging using multidetector-row CT for laparoscopic colorectal surgery.

Laparoscopic colorectal surgery has been attracting attention for its capacity to improve the quality of life (QOL) of patients. However, there are disadvantages to this approach, namely, it is difficult to obtain an image of the entire view of the operative field, and organs and lesions cannot be manipulated directly by the surgeon during surgery. For this reason, it takes a relatively large amount of time to ligate vessel, which can vary between patients. Furthermore, vessels and organs can be damaged during lymph nodes dissection under laparoscopic guidance, leading to heavy bleeding that prevents the surgeon from having access to a good view of the operative field. Then, to assess preoperatively the vascular anatomy, we carried out multiphase, contrast-enhanced examinations using multidetector-row CT (MDCT) on patients with colorectal cancer, and prepared the fused image of 3D images of arteries, veins, the colorectum, organs, and tumor. We called the utilization of 3D imaging virtual CT colectomy, which contributed to rapid and safe manipulation of the origins of the arteries and the veins, as well as lymph nodes dissection, without incurring injury to the involved arteries and veins.

[Three-dimensional CT angiography of the hepatic artery with multislice CT: differences in image quality according to scanning pitch].

Three-dimensional CT angiography was reconstructed from the hepatic artery using multislice CT, and the effect of pitch during scanning on the quality of obtained images was examined. We randomly divided patients into two groups, with images of one group scanned at helical pitch 3 and images of the other at helical pitch 5.5. CT angiography was reconstructed by a volume-rendering technique. Evaluation was done visually, taking the sharpness of images of branches of the hepatic artery as a measure. Three-dimensional imaging scanned at pitch 3 tended to be better than that scanned at pitch 5.5.