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Biomedical subjects

H Shiotani

Publications and source records attributed to H Shiotani.

34 records · Page 2Linked to original sources
PubMed1994

[Exercise-nitroglycerine technetium-99m-2-methoxy isobutyl isonitrile tomoscintigraphic imaging for identifying diseased coronary vessels: comparison with thallium-201 standard exercise-redistribution study].

A same-day double injection protocol employing 99mTc-methoxy isobutyl isonitrile (MIBI) and myocardial single-photon emission computed tomography (SPECT) for detecting coronary heart disease (CAD) was assessed in 21 patients. Our exercise-nitroglycerin (NTG) MIBI study was performed as follows: 150 MBq 99mTc-MIBI was injected at peak exercise, and after 5 minutes 0.3 mg of NTG was sublingually administered. Then, SPECT was performed 1 hour later. Immediately after the 1st imaging, patients were injected of 750 MBq 99mTc-MIBI and were reimaged 1 hour later. Within 1 month, all patients were underwent standard exercise redistribution SPECT thallium (Tl) study. Of the 126 myocardial segments evaluated, 81 were judged as normal by both techniques, while the presence of stress defects were demonstrated in 37 segments (Agreement: 94%). Vessel sensitivities were 75% by MIBI and 67% by Tl. Specificities were 90% by MIBI and 93% by Tl. For the pattern of reversibility in myocardial segments with stress defects, the agreement was 73%. In conclusion, our exercise-NTG MIBI may be safely performed, giving results equivalent to those of standard stress-redistribution thallium studies.

Angina Pectoris↗
PubMed1994

[Myocardial SPECT with iodine-123-labeled beta-methyl-branched fatty acid in patients with angina pectoris].

To evaluate the usefulness of 123I-BMIPP as a tracer of fatty acid metabolism in patients with angina pectoris, we performed rest BMIPP myocardial SPECT and stress 201Tl SPECT in 20 patients with angina pectoris. BMIPP SPECT was evaluated in the defected regions with Tl redistribution. Abnormal findings in BMIPP were observed in 11 of 20 patients and in 14 of 29 myocardial segments with Tl redistribution. Such decreased uptake was observed more often in patients with multivessel disease (64% vs. 12%). In addition, the decreased BMIPP uptake was seen more often in the segments exhibiting hypokinesis than the segments showing with normal wall motion. Thus, BMIPP imaging may be available to detect myocardial ischemia, particularly in patients with severe coronary disease.

Aged↗
PubMed1992

[Clinical usefulness of the quantitative assessment of exercise thallium-201 myocardial imaging in patients with ischemic heart disease].

To clarify the significance of the quantitative analysis of the area of decreased activity in exercise thallium-201 myocardial imaging, 42 patients with one vessel disease (20 patients with angina pectoris without myocardial infarction, 22 patients with old myocardial infarction: MI) were evaluated by exercise thallium scan and compared with clinical findings and wall motion assessed by left ventriculography (LVG). Patients with MI were divided into two groups by LVG (Mild MI: MI with only hypokinesis on LVG, Severe MI: MI with akinesis or dyskinesis on LVG). The degree of defected area was expressed by the ratio of the counts of defected area to the normal area (Relative Activity: RA). RA of the area of decreased activity in patients with angina was higher than that of patients with MI (77.5 +/- 4.59% vs. 65.7 +/- 7.85%, p < 0.05). RA of the area of decreased activity in patients with mild MI was higher than that of patients with severe MI (69.5 +/- 4.78% vs. 61.3 +/- 8.45%, p < 0.01). The above results suggest that the regional thallium-201 uptake ratio in the scintigram may help to differentiate viable zones from necrotic ones and detect the degree of MI.

Evaluation Studies as Topic↗
PubMed1990

Hematoma of the interatrial septum associated with complete atrioventricular block.

A 70-year-old man who had been treated for tongue cancer began to suffer from repeated syncopal attacks. His electrocardiogram indicated complete atrioventricular block. A permanent pacemaker was implanted. He was well for about 2 years after which time he developed dyspnea, suffered from general fatigue, and then suddenly died. A postmortem examination revealed a hematoma approximately 4 x 4. cm in size in the interatrial septum, connected to a noncoronary sinus and rupture of the noncoronary leaflet, which compressed the tricuspid and aortic valves. This hematoma might have been related to the conduction disturbance caused by destructive compression on the conduction system, and his death by the rupture of the noncoronary leaflet.

Aged↗
PubMed1987

The clinical and prognostic significance of dipyridamole Tl-201 emission computed tomography in patients with dilated cardiomyopathy.

To clarify the clinical significance of regional myocardial perfusion abnormality of the left ventricle in dilated cardiomyopathy (DCM), 20 patients with DCM underwent dipyridamole Tl-201 emission computed tomography (ECT). The subjects were divided into 2 groups: group 1 had (n = 9) reversible defects and group 2 (n = 11) had persistent defects only. Group 2 patients significantly advanced heart failure and significantly poorer prognoses than group 1 (55% vs 11% in 2 years survival rate, p less than 0.05). The echocardiographic left ventricular end-diastolic dimension was larger in group 2 than group 1 (68.3 +/- 8.2 mm vs 61.9 +/- 4.0 mm, p less than 0.05) and % fractional shortening was smaller in group 2 than group 1 (18.0 +/- 4.5% vs 24.5 +/- 6.9%, p less than 0.05). Moreover, 12 of the 13 segments with reversible defect showed fairly well preserved left ventricular wall motion, whereas 35 of 58 segments with persistent defect had severely impaired wall motion (1/13 vs 35/58, p less than 0.01). Dipyridamole Tl-201 ECT demonstrated conclusively that the two types of defects (reversible and persistent) are useful to evaluate not only the abnormal myocardial perfusion but also myocardial damage and the prognosis in DCM.

Aged↗
PubMed1987

[Hypertrophic non-obstructive cardiomyopathy assessed by dipyridamole thallium single photon emission computed tomography: comparisons with hypertrophic cardiomyopathy with a dilated heart].

Thallium-201 (Tl) single photon emission computed tomography (SPECT) after dipyridamole infusion (0.56 mg/kg) was performed in 23 patients with hypertrophic non-obstructive cardiomyopathy (HNCM) and in seven patients with HCM simulating dilated cardiomyopathy (HCM-DCM) to clarify the mechanism and clinical significance of decreased coronary vasodilatory reserve. The coronary vasodilatory reserve in the hypertrophied area assessed by SPECT was compared with the findings of echocardiography, left ventriculography and endomyocardial biopsy. 1. Eleven patients with HNCM had no perfusion defects in the hypertrophied area (group I), but the other 12 patients (52.2%) had such defects (group II). All seven patients with HCM-DCM had perfusion defects in the anterior or septal walls (group III). Redistribution was observed in 11 of the 12 patients in group II and in three of the seven patients in group III. 2. The regional washout rate was relatively low in the upper septum in group II and in the anterior wall and upper septum in group III. Thus, coronary vasodilatory reserve in the hypertrophied area was decreased in groups II and III. 3. Echocardiographically, the degree of hypertrophy did not differ between groups I and II, but the latter had significantly greater left ventricular diastolic dimension (42.3 mm vs 49.5 mm: p less than 0.05) and lower percent fractional shortening (%FS) (43.7% vs 35.6%: p less than 0.05). However, group III showed thinner left ventricular wall, much greater diastolic dimension (60.9 mm vs 49.5 mm: p less than 0.05), and lower %FS (24.0% vs 35.6%: p less than 0.05) than did those of group II. 4. On left ventriculography, those in group II showed larger left ventricular end-diastolic volume index (93.9 ml/m2 vs 79.7 ml/m2: p less than 0.05) than that of group I. Left ventricular ejection fraction showed the same tendency, but this was not statistically significant. 5. On endomyocardial biopsy, the specimens of the patients in group II had significantly higher percent fibrosis than did those of group I (11.4% vs 6.8%: p less than 0.05). These findings suggest that the mechanism of decreased coronary vasodilatory reserve in the hypertrophied area may be related to myocardial fibrosis, and this decrease may induce left ventricular dysfunction and compensatory dilatation.

Adult↗
PubMed1987

[Assessment of regional wall motion and myocardial flow in patients with dilated cardiomyopathy using Tl-201 SPECT during dobutamine infusion].

The present study clarified the relationship between wall motion and myocardial flow in dilated cardiomyopathy (DCM). Two-dimensional echocardiography (2-DE) was performed in 14 patients before and after dobutamine (DOB) drip infusion (8 micrograms/kg/min). Thallium-201 emission computed tomography (ECT) was performed after dobutamine infusion and three hours thereafter. The left ventricle was divided into nine segments. In each segment, the degrees of defects were scored from 0 (normal) to 3 (complete defect), and the severity of wall motion abnormalities was scored from 0 (normal) to 3 (akinesis) by visual inspection. 1. Perfusion defects on ECT images were observed during dobutamine infusion in all patients. Redistribution was observed in nine of 14 (64%) patients. 2. During infusion, 38 (81%) of 47 segments without defects showed normal wall motion, but 44 (86%) of 51 segments with defects showed wall motion abnormalities. 3. Redistribution was observed in 18 (35%) of 51 segments, and these segments showed lower incidence of wall motion abnormalities as compared to the other segments (94% vs 45%, p less than 0.001). 4. After infusion, the segments with redistribution frequently showed improved wall motion as compared to the other segments (56% vs 18%, p less than 0.05). These results indicate that redistribution on the ECT image is observed in some patients with dilated cardiomyopathy after dobutamine administration. This may be due to the capacity of the drug to increase myocardial flow in proportion to the increase of oxygen demand.

Cardiomyopathy, Dilated↗
PubMed1985

[201T1 computed tomography using dipyridamole for assessing dilated cardiomyopathy].

The value of redistribution thallium-201 (T1-20(1] emission computed tomography (ECT) using dipyridamole for evaluating coronary circulation was analyzed in 18 patients with dilated cardiomyopathy (DCM). After maximal inducible coronary vasodilation (dipyridamole, 0.56 mg/kg), 2 mCi T1-201 was administered, and dipyridamole ECT data at 10 minutes and delayed ECT data at 3 hours after the injection were collected. Image interpretation was made visually. The results were as follows: In all cases, perfusion defects were observed on the dipyridamole images, and eight (45%) had redistribution on their delayed images. Patients with redistribution had better left ventricular function (% fractional shortening 24.7 +/- 7.0 versus 18.0 +/- 5.0) by two-dimensional echocardiography. Segments with redistribution showed less severe wall motion abnormalities compared with segments without redistribution. It is concluded that redistribution thallium ECT imaging using dipyridamole is a useful tool for the evaluation of coronary circulation of patients with DCM.

Cardiomyopathy, Dilated↗
PubMed1985

[Clinical significance of early redistribution of the exercise-induced thallium-201 defect in ischemic heart disease].

This study clarified thallium-201 (Tl) kinetics in the early stage after exercise in patients with ischemic heart disease (IHD). Tl was administered for 39 patients with IHD and eight normal subjects during maximal exercise. Immediately after exercise, dynamic data were obtained using a double slant-hole collimator at one frame/2 min for a 20 min period. The data of 10 frames (20 min) were spatially smoothed, and semiquantitative segmental analyses of the uptake and kinetics of Tl were performed by computer. In eight normal subjects, Tl uptake was uniform throughout the continuous 20 min, and Tl activity was unchanged throughout the 20 min period after exercise. Among 39 patients with IHD, 39 had Tl defects in the first frame (initial defect). Among 39 initial defects, 15 (38%) showed complete or partial early redistribution as early as 20 min and Tl activity in the defect increased (10.5 +/- 1.5%) over the 20 min period. Early redistribution occurred in 10 (43%) of 23 patients with effort angina and in five (83%) of six patients with variant forms of angina, but in no patients with myocardial infarction. Patients with early redistribution showed a greater frequency either of good collateral vessels or of mild stenosis of the coronary artery, compared with those who had no early redistribution. In conclusion, analysis of Tl kinetics in the early stages after exercise can provide important information about the coronary perfusion state during recovery from transient ischemia, and early redistribution may be a sign of preserved hyperemic flow in the ischemic region.

Angina Pectoris↗
PubMed1984

[Tl-201 single-photon emission computed tomography for clinical assessment of dilated cardiomyopathy].

In some cases of dilated cardiomyopathy (DCM) perfusion defects are demonstrable by Tl-201 imaging at rest. This study clarified the mechanism by which the Tl scan can show myocardial perfusion defects in patients with DCM by means of Tl-201 single-photon emission computed tomography (ECT) utilizing a rotating gamma camera to assess three-dimensional T1 distribution in the myocardium. Thirteen patients with DCM were studied by conventional planar and ECT imaging, and the degree of defects was determined visually. Perfusion defects were observed in 11 of 13 cases (85%) by planar imaging and in all 13 (100%) by ECT imaging. The mean defect score was higher in ECT than in planar imaging (4.15 +/- 1.46 vs 2.23 +/- 1.46, p less than 0.025). A comparative study of defect scores and left ventricular ejection fractions (EF) using gated cardiac blood pool scans established a negative correlation on ECT imaging (r= -0.64), and no correlation on planar imaging (r= -0.38). There was no statistically significant correlation between perfusion defects on planar imaging and regional wall motion abnormalities as observed by two-dimensional echocardiography (2-DE). In contrast, most of the segments with severe defects (defect score greater than or equal to 2) on ECT images showed high grade wall motion abnormalities on 2-DE. Both perfusion defects and wall motion abnormalities in DCM may be closely related to the fibrosis or scar formation in the myocardium. These results indicated that T1-201 myocardial scintigraphy, especially ECT imaging, is of great value in the clinical assessment of patients with DCM.

Adult↗
PubMed1984

[Clinical usefulness of exercise-nitroglycerin myocardial imaging using dual administration of thallium-201].

In order to differentiate transient myocardial ischemia from infarction, the delayed thallium-201 myocardial imaging (redistribution image) is widely utilized, however, the precise mechanism of redistribution remains unsolved. In the present study, we proposed a new method to elucidate myocardial ischemia on images. In normal subjects, patients with old myocardial infarction (OMI) without angina pectoris (AP) and patients with AP, 1.4 mCi of thallium-201 (Tl-201) was intravenously injected at the peak exercise, and immediately myocardial images were obtained in the three projections. Then, 0.3 mg of nitroglycerin (NTG) was sublingually given, and 0.6 mCi of Tl-201 was readministered. NTG myocardial images were analyzed in the left anterior oblique projection and evaluated visually and quantitatively. There was no significant difference in the relative activity on exercise to NTG images in normal subjects and patients with OMI, while patients with AP showed increased activity on exercise to NTG images. Furthermore, the increase in relative activity done by the exercise-nitroglycerin study was greater than that by the conventional exercise-redistribution study in patients with AP. It was concluded that a new method in the present study is able to image myocardial ischemia distinctly and could be useful in clinical studies.

Adult↗