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Biomedical subjects

H Seto

Publications and source records attributed to H Seto.

463 records · Page 26Linked to original sources
PubMedDate not supplied

Measurement of 24-hour whole-body retention of Tc-99mMDP with a thyroid uptake probe: quantitative assessment of metabolic and metastatic bone diseases.

A new method for the measurement of 24-hour whole-body retention (WBR) of Tc-99mMDP, using a thyroid uptake probe with a normal scintigraphic dose was established. Its clinical significance was evaluated in 106 subjects over 20 years old with various bone disorders, including metabolic and metastatic bone diseases. Reproducibility of 24-hour WBR in 10 patients was very good (y = x - 0.3, r = 0.996). The 24-hour WBR of Tc-99mMDP in healthy subjects was 30.4% +/- 4.6%. The WBR values for patients with chronic renal failure, metastatic bone disease, osteomalacia and hyperthyroidism were 98.4% +/- 3.0%, 44.0% +/- 8.0%, 50.7% +/- 2.8% and 39.4% +/- 6.5%, respectively, which were significantly higher when compared with the healthy group. However the WBR of the steroid-induced osteoporotic group was significantly lower (17.3% +/- 5.4%), suggesting the possibility of being able to differentiate osteoporotic patients from healthy subjects. For assessment of the value of 24-hour WBR, simultaneous bone imaging was essential so as to be able to exclude the effects of arthropathy and/or fracture, which were often found in the older age group.

Adult↗
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Double contrast cervical esophagography: use of a specially designed cup to aid double-contrast cervical esophagography.

We designed a cup to aid double-contrast cervical esophagography using photo fluorography and an image intensifier. The cup allows an adequate amount of air to be delivered with the contrast media so that the cervical esophageal lumen expands to give an ideal double contrast image. The clear image is obtained, having to calculate exact timing. The timing sequence we used during the serial radiography was 4 seconds at 2 radiographs per second while the patient continually swallowed the contrast medium and air.

Administration, Oral↗
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Effect of ionic and nonionic contrast media on regional distribution of thallium-201 in rabbits.

Cardiac output is effectively redistributed to each part of the body by regional changes in vascular resistance. Thallium-201 distribution reflects the fractional distribution of cardiac output and parallels regional blood flow. The side effects of iodinated contrast media in different organs have been well documented in animal experiments and clinical studies. However, no simultaneous assessment of regional blood flow change in each part of the body after the administration of contrast media has been reported. Using a double-dose thallium-201 method, we investigated the effect of contrast media on the regional distribution of thallium-201 in each organ as an estimate of regional blood flow change in rabbits. The distribution of 201T1 and 99mTc-MAA was similar in the heart, spleen, kidneys, and leg muscles in the control animals (r = 0.99). The regional distribution of thallium-201 significantly increased in the heart and leg muscle, but decreased in the liver in the nonionic (Iohexol) and ionic (Iothalamate) contrast medium groups as compared with the control group. There were no significant changes in the kidneys or intestine in these three groups in our study. The intravenous infusion of contrast media in rabbits causes uneven redistribution of regional blood flow in the heart, leg muscle and liver. These changes are more prominent in the ionic contrast medium group.

Animals↗
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Thallium-201 single photon emission computed tomography in the evaluation of thymic carcinoma.

Thymic carcinoma is a rare mediastinal tumor that is distinguished from malignant thymoma without cytologic atypia. We present two cases of thymic carcinoma with high uptake of Tl-201. Absence of Tl-201 uptake in a residual mass on the CT scan indicated a lack of tumor viability after the completion of therapy, which was verified by sequential needle biopsy. Tl-201 SPECT seems to be useful both in detecting thymic carcinoma and in assessing the therapeutic effect.

Aged↗
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Primary splenic lymphoma presenting as a large cyst.

An atypical case of splenic lymphoma is presented. A large cystic mass lesion in the splenic area was found in an 80-year-old man. He was involved in a traffic accident, and subsequently the cyst ruptured. The histological diagnosis of malignant lymphoma was made at emergency splenectomy. No other lesions were identified, and there were no signs of tumor recurrence four months after the operation.

Aged↗
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Assessment of treatment response in irradiated lung cancer by sequential thallium-201 SPECT: comparison with tumor volume change and survival time.

We carried out a study to evaluate treatment response and residual mass in irradiated lung cancer with single photon emission computed tomography (SPECT) using 201TI, and investigated the relation among 201TI uptake ratio, tumor volume, and patient survival time. 201TI uptake ratios and tumor volume measured before and after radiotherapy were compared in 14 patients. We divided them into a complete response (CR) group (n = 5) and partial response + no change (PR + NC) group (n = 9) according to the tumor volume response determined by CT, and a longer survival (LS) group (n = 7) and shorter survival (SS) group (n = 7) according to the survival time. The CR group showed smaller 201TI uptake ratios after irradiation (5.3 +/- 6.0%) than the PR + NC group (52.0 +/- 27.4%) (p < 0.01), but there were no significant differences in 201TI uptake ratio before irradiation or survival time in the other two groups. The LS group showed a smaller 201TI uptake ratio before (107.8 +/- 48.3%) and after (17.0 +/- 14.4%) irradiation than the SS group (126.6 +/- 34.4% p < 0.01, 52.6 +/- 27.5% p < 0.05), but there were no significant differences in tumor volume before or after irradiation in the other two groups. We concluded that 201TI SPECT is very useful to evaluate treatment response in irradiated lung cancer and can play a supplementary role in evaluating prognosis.

Adult↗
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↗