PubMed Health⌕ Search

Biomedical subjects

T Shimonagata

Publications and source records attributed to T Shimonagata.

At least 37 records · Page 2Linked to original sources
PubMed1993

Sensitivity and specificity of radionuclide ventriculography with dipyridamole infusion in patients with severe coronary artery disease.

Noninvasive first-pass radionuclide ventriculography may permit the assessment of global and regional left ventricular function during dipyridamole infusion. Twenty patients with > or = 75% stenosis of at least one coronary artery were studied to assess the sensitivity of the technique in detecting coronary artery disease. Seven (35%) had regional dysfunction after dipyridamole infusion, and 16 (80%) developed lower than normal response in left ventricular ejection fraction (an increase of less than 5%) after dipyridamole infusion. When both regional dysfunction and subnormal rejection fraction were considered together, the sensitivity was 80%. Eight normal subjects were studied to assess specificity. None developed regional dysfunction, and left ventricular ejection fraction invariably increased after dipyridamole infusion in all normal subjects, with an increase of less than 5% in only one subject; therefore, the specificity was 88%. It is concluded that the assessment of regional dysfunction with dipyridamole infusion itself is not sensitive, whereas the assessment of changes in left ventricular ejection fraction is sensitive and specific in detecting coronary artery disease.

Coronary Disease↗
PubMed1993

Discrepancies between myocardial perfusion and free fatty acid metabolism in patients with hypertrophic cardiomyopathy.

To test the hypothesis that there are discrepancies between 201Tl- and 123I-beta-methylpentadecanoic acid (BMIPP) distribution in the left ventricular myocardium and to assess whether BMIPP is a useful tracer agent for the assessment of left ventricular function in hypertrophic cardiomyopathy (HCM), myocardial single photon emission computed tomography (SPECT) was performed with 201Tl and BMIPP in five normal subjects and 12 patients with asymmetric septal hypertrophy. Tracer uptake in the left ventricular myocardium was scored using a four-point grading system. A homogenous distribution of the tracer with no discrepancy between 201Tl and BMIPP uptake in the left ventricular myocardium was observed in each normal subject. In contrast, BMIPP uptake was reduced compared to 201Tl in 58 segments (40%) of the 144 myocardial segments in patients with HCM. Such discordant BMIPP uptake was observed in 15 segments (42%) of the septal segments, in 19 segments (53%) of the anterior segments, in eight segments (22%) of the lateral segments, and in 16 segments (44%) of the inferior segments. There was no significant correlation between 201Tl perfusion score and left ventricular ejection fraction, whereas there was a significant correlation between BMIPP perfusion score and left ventricular ejection fraction (r = 0.748; P < 0.01). The results indicated that there were discrepancies between 201Tl and BMIPP uptake in a significant proportion of myocardial segments, suggesting the impairment of fatty acid metabolism and that BMIPP is a useful tracer agent for the assessment of left ventricular function in hypertrophic cardiomyopathy.

Cardiomyopathy, Hypertrophic↗
PubMed1993

Perfusion lung scintigraphy in primary pulmonary hypertension.

15 cases of primary pulmonary hypertension were classified into two groups by patterns of perfusion lung scintigraphy. Perfusion scintigrams showed multiple, small, ill-defined defects (mottled + ve) pattern in eight cases, and the remaining seven cases had a normal (mottled - ve) pattern. The mean pulmonary arterial pressure in patients with a mottled pattern (54 +/- 10 mmHg) was higher than in those with a normal pattern (42 +/- 9 mmHg, p < 0.05). There were no significant differences between the two groups in right ventricular ejection fraction, partial pressures of oxygen in the arterial blood or alveolo-arterial oxygen difference. All the patients with a mottled pattern died within 2 years following the lung scintigraphy. There was a significant difference in the survival curves between the two groups. Although our statistical analysis must be evaluated with caution because of small numbers of patients it is suggested that perfusion lung scintigraphy is useful in assessing the prognosis in primary pulmonary hypertension.

Adult↗
PubMed1993

[The significance of 201Tl/123I MIBG (metaiodobenzylguanidine) mismatched myocardial regions for predicting ventricular tachycardia in patients with idiopathic dilated cardiomyopathy].

123I-MIBG (MIBG) regional defects in myocardial regions with preserved 201Tl (Tl) uptake have been observed in patients with idiopathic dilated cardiomyopathy (DCM). To evaluate whether the presence of Tl/MIBG mismatched regions is related to the occurrence of ventricular tachycardia (VT), we performed myocardial dual SPECT imaging with Tl (111 MBq) and MIBG (111 MBq) in 17 patients with DCM, 11 (Gp A) with and 6 (Gp B) without VT. Myocardial dual SPECT imaging was performed at 15 minutes after and 4 hours after the tracer injection. The regional tracer uptake was scored visually in 6 segments of the basal, middle, and apical short-axial images and in 2 apical segments of the midventricular vertical long-axial image by a four-point scoring system (0 = normal, 1 = moderate, 2 = severe and 3 = complete defect). Then, the severity of tracer maldistributions was assessed by the difference between total defect scores (TDSs) of Tl and MIBG (delta TDS). TDS was not different between Gps A and B in both Tl and MIBG images. However, delta TDS was larger in Gp A than in Gp B (13.5 +/- 6.5 vs. 5.8 +/- 3.0, p < 0.05). Also, the number of segments with the mismatched tracer uptake was larger in Gp A than in Gp B (12.5 +/- 3.0 vs. 8.3 +/- 1.5, p < 0.01). In the electrophysiologic study, we found that the fractionated area corresponded to the mismatched region in 3 of 5 patients in Gp A. These results suggest that regional sympathetic denervation is a possible factor which provocates VT, and myocardial dual SPECT imaging with Tl and MIBG is a useful method for predicting VT in patients with DCM.

3-Iodobenzylguanidine↗
PubMed1993

[Evaluation of left ventricular early diastolic function by first pass radionuclide angiocardiography after dipyridamole infusion in patients with coronary artery disease--comparison with exercise test].

To evaluate the left ventricular early diastolic function after dipyridamole infusion or during exercise, the first pass radionuclide angiocardiography (FPRA) by a multicrystal gamma camera (SIM-400) was performed in 32 patients with coronary artery disease (CAD) and 14 normal subjects. Dipyridamole was administered intravenously (0.56 mg/kg in 4 min). The first third filling fraction (FF 1/3) and the first third mean filling rate (MFR 1/3) were calculated from the time-activity curve. FF 1/3 decreased and MFR 1/3 increased in both normal subjects and patients with CAD during exercise. After dipyridamole infusion, FF 1/3 and MFR 1/3 unchanged in normal subjects, in contrast, FF 1/3 and MFR 1/3 decreased in patients with CAD. Thus, dipyridamole infusion FPRA is more sensitive method to detect early diastolic dysfunction in patients with CAD than FPRA during exercise.

Aged↗
PubMed1993

[Interesting findings of RI venogram in a case with obstruction of inferior vena cava due to compression by the ruptured abdominal aortic aneurysm].

99mTc-MAA venography was performed in a patient with ruptured abdominal aortic aneurysm into inferior vena cava (IVC). Obstruction of lower portion of IVC was considered to be due to the compression by ruptured abdominal aortic aneurysm, which was confirmed at surgery. Subsequent scintigram revealed abnormally high RI uptake in the whole liver and a hot spot in the middle antero-inferior segment of liver, which may be characteristic for such a condition.

Aged↗
PubMed1993

[Increased lung uptake and transient left ventricular dilatation at stress myocardial scintigraphy with 99mTc-MIBI].

On exercise 201Tl scintigraphy in coronary artery disease, left ventricular transient dilatation (LVTD) and increased lung uptake were noted as a marker of multivessel critical stenosis. To compare the two markers of 99mTc-methoxyisobutyl isonitrile (MIBI) and 201Tl, planar and SPECT myocardial scintigraphy were performed with both radiopharmaceuticals in 27 patients with ischemic heart disease. Lung uptake (lung/max myocardial ratio) of MIBI was significantly lower than that of 201Tl, but the relationship of the lung uptake was linearly correlated (r = 0.77). The LVTD ratio (mean radial ratio = m-RR) was determined by the mean radius of the immediate postexercise short axial image by that of rest (redistribution) image. There was no significant correlation between the m-RR of 201Tl and that of MIBI (r = 0.27). We suggest that the mechanism of LVTD is due to not only subendmyocardial ischemia but also another factors.

Aged↗
PubMed1992

[Detectability of diagonal branch disease by 201TlCl exercised myocardial scintigraphy].

The detectability of diagonal branch disease in 10 patients (five with angina pectoris, five with myocardial infarction) with isolated diagonal branch lesions (more than 75% luminal stenosis in coronary angiography) was reviewed. In exercised 201TlCl myocardial scintigraphy, chest pain occurred in four of 10 patients, electrocardiographic change indicating myocardial ischemia was seen in four, and diagonal branch lesion was detected in only four patients by planar images. In contrast, diagonal branch lesions were detected in 10 of 10 patients by SPECT (single photon emission computed tomography). In planar images, perfusion defects appeared high in the anterolateral, posterolateral, and anterior walls of the left ventricle. In SPECT images they appeared high in the anterior to anterolateral wall. The extent of diagonal branch lesions could be quantitatively evaluated by coronary territory maps developed from unfolded maps of exercised SPECT. The mean ratio of the extent of diagonal branch lesion to left anterior descending branch territory was 24.7%, and the extent of myocardial infarction was significantly larger than that of angina pectoris (p < 0.05). In conclusion, SPECT is useful for detecting diagonal branch lesions and can quantitatively show the extent of these lesions by coronary territory map.

Aged↗
PubMed1992

Assessment of myocardial viability by using newly developed myocardial SPECT imaging.

Thallium myocardial imaging has been widely available for the detection of myocardial ischemia and assessment of myocardial viability in coronary artery diseases. However, myocardial imaging using SPECT and gamma-emitting radiopharmaceuticals has been developed for accurate evaluation of myocardial infarction and ischemia. The present study was undertaken to clinically evaluate myocardial necrosis, metabolism and sympathetic nerve activity. In this study, myocardial fatty acid metabolism was assessed using 123I-BMIPP, myocardial sympathetic neural activity was assessed using 123I-MIBG and myocardial necrosis was assessed using 111-In-antimyosin Fab. Dual energy SPECT using these new agents and thallium gives precise characterization of myocardial viability in coronary artery disease.

3-Iodobenzylguanidine↗
PubMed1992

[Dipyridamole-thallium myocardial imaging in patients unable to exercise adequately: comparison with arm and bicycle ergometer].

We assessed the usefulness of dipyridamole-thallium myocardial imaging in patients unable to exercise adequately, compared with arm-ergometer and standard (bicycle) ergometer. Fifty-six patients with arteriosclerosis obliterans, aortic aneurysm, aortic dissection and so on, who were revealed normal imaging, were studied. Only one of 13 cases with arm-ergometer and two of 14 with bicycle ergometer reached target heart rate. Lung thallium uptake in the cases with arm-ergometer (37 +/- 9%) is higher than that with dipyridamole (29 +/- 5%). This elevation may be confused with pectoralis muscle uptake. Washout rate is 45 +/- 9% with dipyridamole and 46 +/- 12% with bicycle ergometer, respectively, though there was no significant differences. Myocardial/background counts ratio with dipyridamole (4.6 +/- 0.8%) is significantly higher than that with arm and bicycle ergometer (arm-ergometer; 3.5 +/- 0.7, bicycle ergometer; 4.2 +/- 0.9). Then, myocardial image with dipyridamole have superior quality. We concluded that dipyridamole-thallium myocardial imaging is very useful in the patients who have suboptimal exercise efforts.

Aged↗
PubMed1992

[Influence of hypertensive left ventricular hypertrophy on detection of ischemic area with exercise thallium-201 myocardial scintigraphy].

Sixty-four patients with single left anterior descending artery disease having effort angina (group A: 40 patients without hypertension, group B: 10 patients with hypertrophic hypertension, group C: 14 patients with non-hypertrophic hypertension) were assessed the influence of hypertensive left ventricular (LV) hypertrophy on detection of ischemic area. The criterion of hypertrophy by two-dimensional echocardiography was > 12 mm in the wall thickness of interventricular septal or posterior wall. Population in Group B might show low detectability in ischemic area by 201Tl myocardial scintigraphy (positive thallium rate 60%, defect score 2.7 +/- 3.6), and high lung thallium uptake and high frequence of ECG positive among three groups. In semiquantitative analysis, the washout rate of the posterolateral wall and %RD (delayed %uptake-initial %uptake) of the septal wall in patients with Group B were lowest among three groups. However, the washout rate in the septal wall against the posterior wall, and the initial %uptake and the delayed %uptake of the septal wall were not significantly different among three groups. We could conclude that the decreased washout rate in nonischemic area with hypertensive LV hypertrophy might make the ischemic area masked.

Aged↗
PubMed1992

[Diagnostic accuracy of coronary artery lesion by 99mTc-MIBI exercise myocardial scintigraphy--containing the utility of simultaneous assessment of left ventricular function].

To determine whether technetium-99m hexakis-2-methoxy isobutyl isonitrile (99mTc-MIBI) myocardial scintigraphy is a superior method in the detection of coronary artery disease, exercise and rest 99mTc-MIBI planar and SPECT scintigraphy were performed on 27 patients with coronary artery disease. When 99mTc-MIBI (555 MBq (15 mCi)) was injected, first-pass radionuclide angiography (FPRNA) was simultaneously performed by a new mobile multicrystal gamma camera (SIM-400), and LV function (LVEF) was evaluated quantitatively. Visual semiquantitative detection of coronary lesions using 99mTc-MIBI images showed superior accuracy to that obtained using 201TlCl images. 99mTc-MIBI SPECT images were particularly useful in diagnosing LCX and RCA lesions. Moreover, the simultaneous assessment of perfusion and left ventricular function by 99mTc-MIBI FPRNA proved to be useful in the diagnosis of multi-vessel disease. In summary, 99mTc-MIBI SPECT scintigraphy with simultaneous assessment of left ventricular function showed better diagnostic accuracy than 201TlCl myocardial scintigraphy.

Aged↗
PubMed1992

[Thallium-201 scintigraphy after dipyridamole infusion in patients with ischemic heart disease--comparison with maximal exercise].

Myocardial images after dipyridamole infusion (DIP-Tl) were compared with maximal thallium-201 images (Ex-Tl) to determine the utility for detecting coronary artery disease and the ischemic level in ischemic regions. Ex-Tl was performed in 36 patients of angina pectoris (Group 1), and DIP-Tl was performed in 22 patients of angina pectoris (Group 2), who were divided into two groups (Group 2a: 15 patients with low level exercise, Group 2b: 7 patients without low level exercise). Each group had normal controls (41, 27 and 31 people). The detectability of coronary artery by DIP-Tl was almost same with Ex-Tl (sensitivity 85% vs. 86%, specificity 80% vs. 95%). In the case of normal controls, the mean washout rate of group 2b was 44.4%, which was less than other two groups (50.6% for group 1, 48.8% for group 2a). And the mean myocardial/background (M/B) ratio of group 2b was 4.3 less than other two groups (4.7 for group 1, 4.9 for group 2a). In the case of the patients of angina pectoris, washout rate, M/B ratio, initial % uptake and delayed % uptake in the ischemic region were almost same among the 3 groups. This study demonstrates that DIP-Tl is as effective as Ex-Tl, and the ischemic level in the ischemic region is almost same among the 3 groups. But the thallium accumulation in the background of the group 2b is slightly higher than other two groups in the normal controls, so it is suggested that the image after only dipyridamole infusion becomes slightly unclear.

Coronary Disease↗
PubMed1992

[Diagnostic utility of myocardial imaging using 123I-labeled beta-methyl-iodophenyl pentadecanoic acid in ischemic heart disease].

We evaluated the myocardial metabolism in the acute and subacute phases of myocardial infarction or unstable angina using 123I-labeled beta-methyl-iodophenyl pentadecanoic acid (BMIPP). We then compared those findings with (1) myocardial perfusion images obtained with 201TlCl and (2) the regional and global left ventricular function determined by left ventriculography. Thirty-one patients were examined, consisting of 16 with acute myocardial infarction (6.8 +/- 2.6 days after onset), 8 with subacute myocardial infarction (35 +/- 3.0 days after onset) and 7 with unstable angina. The BMIPP images showed a larger uptake-defect than 201TlCl images in the patients in the acute or subacute phase of myocardial infarction. This finding was especially remarkable in the acute phase after successful coronary revascularization therapy. Moreover, in such cases, the myocardial BMIPP uptake improved to the same degree as 201TlCl one month later. The decrease in myocardial uptake of BMIPP agreed well with the decrease in regional wall motion in the acute and subacute phases of myocardial infarction. In contrast, the myocardial perfusion of 201TlCl did not always agree with the regional wall motion in stunned or hibernating myocardium, where BMIPP showed an uptake-defect in the acute phase but improved in the subacute phase. Thus, BMIPP is surmised to be able to depict fatty acid metabolism in in vivo myocardial imaging.

Adult↗
PubMed1992

[Usefulness of 201Tl myocardial scintigraphy after dipyridamole infusion in patients with atherosclerotic vascular disease].

To determine the utility for detecting ischemic heart disease (IHD), Dipyridamole thallium myocardial images (DIP-Tl) have been performed in the 103 patients with atherosclerotic vascular disease who can't exercise fully. Of 103 patients, there were 36 patients with arteriosclerosis obliterans (ASO), 31 patients with aneurysm of the abdominal aorta (AAA), 24 patients with aneurysm of the thoracic aorta (TAA) and 12 patients with dissecting aortic aneurysm (DAA). Clinical evidence of IHD was found in 20 patients with ASO, 10 with AAA, 7 with TAA and 4 with DAA respectively. Positive evidence of DIP-Tl was identified in 66% of 41 patients who had clinical evidence of IHD, and particularly in the patients with AAA (80%) and ASO (65%). On the other hand, in the patients without clinical evidence of IHD, positive evidence of DIP-Tl was identified in 19% of 62 patients and particularly in the patients with AAA (39%). In all patients, the percentage of the positive DIP-Tl ratio was 38%. And, when the 38% patients of the positive DIP-Tl were added to the patients of the negative DIP-Tl who had clinical evidence of IHD, almost half patients (51%) were considered to be complicated with IHD. This study suggests that the atherosclerotic vascular disease is highly complicated with IHD and DIP-Tl is useful to detect IHD.

Aged↗
PubMed1991

[Primary cardiac tumor with singular findings on cardiac radionuclide scintigraphy].

We encountered a primary cardiac tumor originated from the right atrium or pericardium with singular findings on cardiac radionuclide scintigraphy. The patient was 43-year-old female who showed asymptomatic cardiomegaly and abnormal cardiac silhouette by chest X-ray. First pass radionuclide angiography using Tc-99m pertechnetate revealed the abnormal stain filled from the stem of ascending aorta inner and outer portion of the right atrium. Selective angiography showed that the main feeding artery of the tumor was right coronary artery and right internal mammary artery. The pathological diagnosis of the surgically resected specimen was angiosarcoma. It was suggested that detail evaluation of first pass radionuclide angiography give us a useful clinical information linked the feeding artery of cardiac tumor in this case.

Adult↗
PubMed1991

[Prognostic significance of radionuclide-assessed right ventricular function in dilated cardiomyopathy].

To assess the prognostic significance of right ventricular function in dilated cardiomyopathy (DCM), we studied consecutive 57 DCM patients. There were 41 men and 16 women, whose mean age was 48 ys. (range 3-68 ys.). The mean LVEF in all patients was 29 +/- 11%, and the mean interval from the onset of symptom of cardiac failure (CHF history) was 4 ys. (range 0-33 ys.). With follow-up of 3.8 ys., five patients had died until the first year, and 14 had died until the third year. By using multivariate regression analysis, there were no prognostic significance in clinical parameters such as age, CHF history, sex, atrial fibrillation, except for NYHA class, and medication at the third year. In survival curves according to Kaplan-Meier method, RVEF and mean PA had predictive value (p less than 0.05), while LVEF did not. The patients with RVEF less than 45% had poor survival rate compared to those with RVEF greater than or equal to 45%. The patients with RVEF less than 45% showed lower LVEF and LVESVI. RVEF may offer prognostic predictive value through the effect of not only mean PA but also left ventricular parameter. In conclusion, radionuclide assessment of right ventricular function should be valuable for the prognostic evaluation of DCM patients.

Adolescent↗