Biomedical subjects

H Seto

Publications and source records attributed to H Seto.

456 records · Page 26Linked to original sources

PubMedDate not supplied

Doppler spectral analysis of blood flow velocities in common femoral artery: age-related changes in healthy subjects and characteristics of abnormal hemodynamics in obstructive arterial disease.

Flow velocity patterns in the common femoral artery were analyzed in 66 lower extremities of 33 healthy subjects and 18 lower extremities of 12 patients with arteriosclerosis obliterans (ASO) by Doppler ultra-sonography. In a phantom study, Doppler flow velocity showed a close correlation with actual flow velocity: y = 1.02x - 1.22 (r = 0.995). In clinical trials, 33 healthy subjects were classified into three groups: group I (20-40 years), group II (41-60 years) and group III (61-80 years). Starting time of acceleration (STA) was shortened as age increased. Peak reverse velocity (PRV), maximum deceleration rate (MDR), and pulsatility index (PI) were significantly decreased in group III as compared with groups I and II. In patients with ASO, STA was prolonged, and PFV, PRV, MAR, MDR, PI, VSA, and FV were significantly decreased (p < 0.001) as compared with healthy control group III. Consequently, marked characteristic changes such as flattening of curves and disappearance of reverse flow in Doppler flow wave-form were observed. These data obtained by Doppler ultrasonography are thought to be useful for the early diagnosis and follow-up of patients with ASO.

Adult↗

PubMedDate not supplied

Normal appearance of the esophagus in sagittal section; measurement of the anteroposterior diameter with ECG gated MR imaging.

Sagittal images are valuable for determining the location and local extent of esophageal tumors. However, the normal appearance of the esophagus in sagittal section has not yet been analyzed well, although there have been a few reports on normal esophagus in the axial plane. In this study, the anteroposterior (AP) diameter of normal thoracic esophagus was measured in sagittal images using ECG gated magnetic resonance (MR) imaging, and compared with that of cadavers. In 78 subjects, 222 of 234 portions (95%) were depicted well when the esophagus was divided into three portions (upper thoracic, middle thoracic, and lower thoracic and abdominal). Almost all the AP diameters (96%) were within 15-16 mm. The data correlated well with the measurements in cadavers. The AP diameter of normal thoracic esophagus in sagittal section was considered to be up to 16 mm. These results might be of clinical use to evaluate the location and extent of esophageal tumors.

Adolescent↗

PubMedDate not supplied

Discordant technetium-99m HMPAO and thallium-201 chloride distribution in brain tumors.

We present four cases of primary brain tumors in which both Tc-99m HMPAO and Tl-201 chloride localized in the tumors, but with discordant distribution. Larger accumulation with Tc-99m HMPAO than Tl-201 chloride was observed in two patients (one astrocytoma and one meningioma). This was related to localization of the tracer in the tumor as well as in the adjacent hyperemic region as compared with the MRI findings. In one patient with pituitary adenoma, Tc-99m HMPAO localized in nearly the entire tumor, similar to the result with Tl-201 chloride. In one patient with astrocytoma, Tc-99m HMPAO showed partial tumor accumulation, less than that shown by Tl-201 chloride. Tc-99m HMPAO uptake by brain tumors does not always reflect the viable tumor burden as compared with the distribution of Tl-201 chloride and MRI or CT findings.

Adult↗

PubMedDate not supplied

Use of MR angiography in a pregnant patient with thalamic AVM.

A 32-year-old pregnant woman at 29 gestational weeks suffered from the acute onset of severe headache. Brain CT, MRI, and MR angiography (MRA) showed intraventricular and thalamic hemorrhage, ruptured from a thalamic AVM. Based on these findings, conservative treatment was continued until delivery. After cesarean delivery at 34 gestational weeks, conventional cerebral angiography was performed, followed later by gamma-knife therapy. In pregnant patients with suspected cerebrovascular disorders, MRI and MRA should be the first of choice method to evaluate information on the diseased vessels and associated lesions since there is no radiation risk or side effects of contrast medium.

Adult↗

PubMedDate not supplied

Malignant gastrointestinal stromal tumor of the small intestine: radiologic-pathologic correlation.

Neoplasms of the small intestine are very rare. Gastrointestinal stromal tumors (GISTs) are one of the new undifferentiated stromal tumors of the gastrointestinal tract diagnosed by immunohistochemistry. We present a case of a malignant GIST arising from the small intestine and report the radiologic characteristics of the tumor and pathological correlation. CT showed a very large, enhancing mass with extensive central necrosis located on the mesenteric side of the jejunum. A perforation into the jejunal lumen was observed by upper GI series. MRI showed a very large tumor which was hypointense on T2-weighted images. Ultrasound revealed a mixed solid and cystic mass. Grossly, the tumor was solid peripherally with extensive central necrosis. Microscopically, it consisted of spindle and epithelioid cells. Immunohistochemically, the cells stained positive for CD34, which is diagnostic of GIST.

Antigens, CD34↗

PubMedDate not supplied

CT evaluation of gastric cancer: depth of tumor invasion and pancreas invasion.

PURPOSE: To compare the internal structure of tumor and the contiguous organ configuration on computed tomography (CT) with the depth of tumor invasion on the pathological specimen. METHODS: Sixty-four gastric cancers depicted on incremental dynamic CT were classified according to the internal structure of the tumor, and correlated with the depth of tumor invasion. In addition, the cancers were classified according to the contiguous pancreatic configuration, and correlated with the degree of pancreatic invasion. RESULTS: Eleven tumors with thickened gastric wall consisting of both a thick inner layer of high attenuation and a thin outer layer of low attenuation (two-layered tumor with a thin outer layer) did not invade the serosa: mucosa (n = 5) and submucosa (n = 6). Of 59 gastric cancers with a regular margin to the contiguous pancreas, pancreatic invasion was absent in 58 and present in one. Pancreatic invasion was present in all of five gastric cancers with an irregular margin. CONCLUSIONS: Our results indicate that two-layered gastric tumors with a thin outer layer never invade the serosa. Furthermore, pancreatic invasion is predicted only when the margin of the contiguous pancreas is irregular.

Adult↗