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Biomedical subjects

H Seto

Publications and source records attributed to H Seto.

At least 451 records · Page 25Linked to original sources

MR sialographic evaluation of sialectasia of Stensen's duct: comparison with X-ray sialography and ultrasonography.

We describe a patient with unilateral sialectasia of Stensen's duct. X-ray sialography, MR sialography, and ultrasonography showed multiple stenoses and rosary dilatation of Stensen's duct during stimulation of the parotid gland. Before stimulation, Stensen's duct showed focal dilatation as indicated by MR sialography and ultrasonography. The patient also had ipsilateral masseter hypertrophy (BMH), which may be a cause of sialectasia.

Adult↗

Effect of diets containing different levels of calcium, phosphate, and vitamin D3 on tooth uptake of 47Ca-chloride in rat models: comparison with bone uptake.

The effect of dietary manipulation on global tooth uptake of 47Ca-chloride was evaluated in three rat models of metabolic bone diseases verified by histologic bone study. The 24-hr tooth uptake of 47Ca-chloride was significantly decreased in the osteomalacic group, and was increased in the osteoporotic group at the fourth week. Tooth uptake closely paralleled femoral uptake at a correlation coefficient of 0.73 (p less than 0.01). The uptake of 47Ca-chloride in tooth was found to be more affected by dietary manipulation than that in femur in our rat models.

Animals↗

Biodistribution of intravenously injected [131I]Lipiodol in rats.

Tissue distribution studies of intravenously injected [131I]Lipiodol in rats were performed, and serial whole-body autoradiograms were obtained simultaneously for seven days. Most of the radiotracer was retained in the lungs. Lung uptake reached a maximum (42.44% ID/g) at 1 day, with an effective half-life of 3.0 days. The other organs showed markedly lower uptakes (less than 0.56% ID/g). The ratio between liver and lung reached a maximum (0.01) at 3 hr and then decreased with time, precluding adequate external imaging of the liver as compared with the lung.

Animals↗

A case of liver echinococcosis mimicing a solid liver tumor.

A case of hepatic echinococcosis mimicing a solid tumor was presented. The echinococcosis appeared as an echogenic mass in US, a low density area in CT, and an area of low (T1-weighted image) and high (T2-weighted image) intensity in MRI. Echo-guided biopsy showed PAS-positive cuticle layer of echinococcus in the necrotic tissue. Anular features around the lesion noted in MRI seemed to imply increased hepatic tissue water (congestion and/or edema). When a solid tumor is noted in the liver, proper history taking and awareness of this disease will decrease the chance of misdiagnosis.

Adenoma, Bile Duct↗

Precision of total-body and regional bone mineral measurement by dual-energy X-ray absorptiometry.

The precision of total-body and regional bone mineral measurements from whole body scans obtained by dual-energy X-ray absorptiometry (DEXA) was determined in a phantom and two normal subjects. Whole body scans were performed once a week for three months at the speed of 80 mm/sec. Coefficients of variation for measurements of total-body bone mineral content (BMC) in the phantom and the subjects were 1.7% and 1.5% (average), respectively. Moreover, plots of total-body BMC values with time showed no significant slope, indicating the stability of the instrument. Regional BMC measurement from whole body scans, however, resulted in larger precision errors than total-body BMC measurement. This is attributed to the more rapid scan speed and coarser scan width used in whole body scanning as compared with regional scanning. Good precision of total-body BMC measurement by DEXA is of great clinical value in the assessment of metabolic bone disease.

Absorptiometry, Photon↗

Bone mineral density of the lumbar spine by dual photon absorptiometry: age-related regression in normal Japanese subjects and fracture threshold in osteoporotics.

The bone mineral density (BMD) of the lumbar spine was determined by DPA in 280 normal Japanese volunteers and 11 osteoporotic women with compression fractures. In women, bone loss started from the mid thirties and accelerated after the age of 50 years at the rate of 0.75% (0.0074 g/cm2) per year. In men, bone loss started from the mid twenties and occurred linearly at the rate of 0.30% (0.0032 g/cm2). The overall diminutions in vertebral BMD throughout life in men and women were 13.0% and 24.3%, respectively. The mean vertebral BMD of the osteoporotic women with recent compression fractures was 37.5% lower than that of age-matched controls. The 90th percentile for vertebral BMD in this group was 0.584 g/cm2. By the age of 80 years, approximately one-fifth of normal Japanese women have BMD values less than this.

Adult↗

Pancrease divisum: CT and ERCP findings.

A case of pancreas divisum diagnosed by CT is reported. ERCP via the major pipilla revealed a very short pancreatic duct, which appeared to be abruptly interrupted by a tumor. CT, however, demonstrated two definite pancreatic moieties separated by a fat cleft, indicating the presence of pancreas divisum.

Aged↗

Comparison between air CT and MRI in the detection of small acoustic neurinomas.

Air CT proved useful in yielding images of acoustic tumors as an air filling defect in 11 (24%) of 46 patients. Six of the 11 tumors were small ones of less than 1 cm in diameter. Air CT was also able to exclude an intracanalicular tumor in 29 patients (63%). MRI was performed for comparison in eight patients (nine tumors) already diagnosed by air CT as having an acoustic tumor. MRI detected eight (89%) of nine tumors. A false negative result on MRI was obtained only in one intracanalicular tumor (4.3 mm in size). This was considered to be attributable to limitations of spatial resolution including the wide slice thickness. A protocol for radiological investigation and management of patients whose clinical symptoms and/or audiovestibular examination are highly indicative of acoustic tumor is proposed and discussed.

Adult↗

Evaluation of the degree of severity in liver cirrhosis by computed tomography.

As CT findings useful for the evaluation of the degree of severity in liver cirrhosis, the following items were chosen for statistical analysis: atrophy of the right lobe, enlargement of the left lobe, irregularity of the liver surface, ascites, varices or collaterals, and dilatation of the SMV. According to the frequency with which these six items were found, the CT findings were expressed in the form of a score, and the resulting scores agreed well with ICG values, portal-venous flow (Qp) ratios obtained from radionuclide angiography, and the scores on the Child-Turcotte criteria. A score of 5 or 6 meant severe cirrhosis. A score of 4 meant liver cirrhosis, however, the degree of severity could not be determined, because there was overlap among the cirrhotic groups. A score of 3 meant liver cirrhosis with a probability of about 90%. A score of 1 or 2 was nonspecific for evaluation. When a score of 0 was noted with splenomegaly, there was a probability of more than 90% that it was chronic hepatitis. In conclusion, this approach was considered to be useful for evaluating the degree of severity in liver cirrhosis and differentiating between liver cirrhosis and chronic hepatitis to some degree in Japanese.

Adult↗

Pulmonary arteriovenous malformation: radionuclide detection and quantification of right-to-left shunting.

Radionuclide detection and quantification of right-to-left shunting in two patients with pulmonary arteriovenous malformation and Rendu-Osler-Weber disease are described. Radionuclide studies are simple, atraumatic, and clinically useful in determining the vascular nature of the lesion and in quantifying the amount of right-to-left shunting with reasonable accuracy both before and after operation.

Adult↗

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↗

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↗

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↗

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↗

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↗

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↗

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↗