Biomedical subjects

Hiroko Satake

Publications and source records attributed to Hiroko Satake.

22 records · Page 2Linked to original sources

PubMedDate not supplied

Pancreatic ductal adenocarcinoma showing iso-attenuation in early-phase contrast-enhanced CT: comparison with histopathological findings.

PURPOSE: To clarify the CT characteristics and histopathological findings of pancreatic ductal adenocarcinomas that are not detected in early-phase contrast-enhanced CT images. MATERIALS AND METHODS: The CT findings of eight patients with histopathologically proven pancreatic carcinomas that were not detected in early-phase images following the rapid injection of contrast material were reviewed. The examinations consisted of pre-contrast-enhanced CT and multi-phase contrast-enhanced CT, with thin-section scanning in each patient. The CT findings were compared with those of the resected specimens. RESULTS: In all cases but one, the lesion was in the pancreatic head. In seven cases, the tumor did not appear as a focal area of hypoattenuation compared with surrounding pancreatic parenchyma in early-phase images, and in the remaining case, small areas of poor enhancement were observed. In late-phase images, hyperattenuated and isoattenuated areas were seen in six and two cases, respectively. In all but one case, the lesion was less than 40 mm in size. All lesions were composed of acinar tissues and tumor cells, and contained small amounts of mucin, necrotic tissue, and pus. The fibrous tissues were not abundant and were interlobular and/or relatively loose. CONCLUSION: Pancreatic ductal adenocarcinomas showing isoattenuation in early-phase images tend to be relatively mild lesions with scirrhous and/or desmoplastic changes.

Adenocarcinoma↗

PubMedDate not supplied

Usefulness of a method for changing tube current during helical scanning in multislice CT.

PURPOSE: To determine whether employing a method for changing the tube current during helical scanning helps to adapt the image noise among various sections of the upper abdomen and chest in multislice computed tomography (CT). MATERIALS AND METHODS: One hundred CT examinations of the upper abdomen were assigned to one of two scanning protocols: standard scanning with a constant tube current and scanning with the changing method based on protocol 1. One hundred fifty CT examinations of the chest were assigned to one of three protocols: standard scanning with a constant tube current and scanning with the changing method based on protocols 1 and 2. In protocol 1, the tube current for each rotation was reduced in proportion to the water equivalent thickness based on the rotation showing the maximum value, while, in protocol 2, the tube current was increased in proportion to the water equivalent thickness based on the rotation showing the minimum value. The mean tube current, mean standard deviations (SDs) of the measured CT numbers, and dispersion of the SDs were compared between the different protocols. RESULTS: In the upper abdomen, the use of the changing method based on protocol 1 resulted in a significant reduction in the dispersion of the SDs of CT numbers, with no increase in mean tube current or mean SDs. In the chest, use of the changing method based on protocol 2 resulted in a significant reduction in the dispersion of the SDs of CT numbers, with a reduction in mean tube current and no increase in mean SDs. CONCLUSION: The method for changing tube current during helical scanning makes it possible to adapt the image noise among various sections of the upper abdomen and chest without increasing dose in multislice CT.

Adult↗

PubMedDate not supplied

Evaluation of abdominal aortic aneurysm for endovascular stent-grafting with volume-rendered CT images of vessel lumen and thrombus.

PURPOSE: To evaluate the accuracy of CT images of abdominal aortic aneurysm (AAA) with volume-rendered (VR) display of vessel lumen and thrombus and to evaluate its usefulness in the planning of stent-grafting. MATERIALS AND METHODS: Helical CT was performed in 11 patients with AAA. Volume data of the vessel lumen and thrombus were separately extracted, and the VR images were reconstructed. Vessel measurements were made by five radiologists and compared with the axial and multiplanar reconstruction (MPR) images. Angiography and intravascular ultrasonography were used as standard references. The relations of aneurysmal sac to the major arterial branches and the subjective overall diagnostic value were evaluated by using a continuous rating scale. RESULTS: Accuracy of measurements was higher on VR images than on axial/MPR in 7 of 13 regions. Interobserver variance of VR images was smaller in 7 of 14 regions. Detection of renal and internal iliac artery involvements was better on VR images (p<0.05). Overall diagnostic value was also higher on VR images (p<0.05). CONCLUSION: VR CT images of vessel lumen and thrombus are supportive of and supplementary to conventional axial/MPR images in planning stent-grafting for AAA.

Aged↗

PubMedDate not supplied

Multi-slice CT of thyroid nodules: comparison with ultrasonography.

PURPOSE: To evaluate the usefulness of multi-slice computed tomography (MSCT) in comparison with ultrasonography (US) for the differentiation of benign from malignant thyroid nodules and the evaluation of tumor extension. MATERIALS AND METHODS: Thirty patients with thyroid nodules (14 malignant, 16 benign) who underwent both MSCT and US participated in the present study. MSCT with contrast enhancement was performed, and 3D shaded volume rendering (SVR) and multiplanar reconstruction (MPR) were employed to differentiate benign from malignant nodules and to evaluate tumor extension. US images were obtained using a 7.5 MHz annular array probe. A three-point rating scale was used for image interpretation, and the kappa statistic was employed to evaluate agreement between MSCT and US. RESULTS: Sensitivity in differentiating benign from malignant nodules was found to be 85.7% for US and 78.6% for MSCT. Disagreement between MSCT and US occurred in assessing the homogeneity of the solid component and the presence of fibrous capsule. In two of seven T4 cases, MPR provided a more accurate diagnosis than US examination in detecting extracapsular invasion. CONCLUSION: For differential diagnosis of thyroid nodules, US was found to be better than MSCT. However, MSCT could be useful for the evaluation of advanced cases with suspicion of extracapsular extension.

Diagnosis, Differential↗