Evaluation of viral myocarditis in children by radionuclide method.

Evaluation of viral myocarditis is essential for the clinician to assess the prognosis. In this study, Tl-201 myocardial scintigraphy and Tc-99m gated cardiac blood pool scan were performed in 16 patients with myocarditis diagnosed by clinical symptoms and laboratory findings and these nuclear medicine techniques were followed up for 5 years. Exercise Tl-201 scintigraphy using a bicycle ergometer was performed in 8 patients by SPECT imaging. There were mild to severe persistent defects found in all cases (100%), but pressure rate products showed normal response. The Tl-201 defect ratio improved gradually, but did not change significantly. In the resting Tl-201 image one of 16 patients showed severe multifocal defects. LVEF increased significantly from 1 year to 5 years after onset, while RVEF measured by gated blood pool scans showed slight increases 3 years to 5 years after diagnosis. It was concluded that myocardial perfusion improved only incompletely. Cardiac function (LVEF and RVEF) improved gradually, and pressure rate products were normal. Myocarditis should therefore be followed up in order to assess the prognosis; moreover, the relationship of myocarditis to dilated cardiomyopathy needs to be further studied.

[Assessment of relative washout rate (rW-R) in stress T1-201 myocardial SPECT].

Stress T1-201 myocardial SPECT was performed and evaluated quantitatively by Bull's eye method in 54 patients with single vessel coronary artery disease (33 angina pectoris, 21 myocardial infarction) who underwent successful PTCA. As the index of myocardial ischemia and viable muscle that was not affected by work load and others, relative washout rate (rW-R) was calculated from the formula: washout rate (W-R) of ischemic area was divided W-R of normal area. The purpose of this study was to examine the significance and usefulness of rW-R. Good correlation was recognized between grade of coronary artery stenosis, severity score (Sv-S) and rW-R in 28 patients with effort angina pectoris (EAP). Therefore, rW-R was regulated with coronary flow in EAP. On the other hand, in 5 patients with vasospastic angina (VSA), there was a tendency that rW-R showed low value compared with Sv-S. It was suggested that rW-R in patients with VSA was regulated not only coronary flow but also other factors. As a result of study before and after successful PTCA, rW-R foresaw the improvement of coronary perfusion and work load capacity by successful PTCA exactly. It was concluded that W-R reflected myocardial ischemia and myocardial viability accurately, and rW-R was a useful clinical index.

[The evaluation of the therapeutic effect on acute myocardial infarction by radioisotope method--assessment of the intravenous injection of urokinase and comparison with the results of PTCR + PTCA].

The therapeutic effect of intravenous injection of Urokinase (UK method) on acute myocardial infarction (AMI) was studied and compared with the results of the therapeutic effect of PTCR + PTCA. The subjects comprise 108 cases with AMI, and a radioisotope examination was performed in the acute stage to calculate LVEF and Tl-defect ratio (Tl-DR). Measured by the UK method, Tl-DR in the group given 1.2 X 10(6) units of UK was 1.63 +/- 0.8, which was lower than the 2.4 +/- 1.33 for the group given 9.6 X 10(5) unit of UK, whereas a favorable therapeutic effect was obtained in both groups compared to 3.5 +/- 2.5 in the control group. In the group given UK within 6 hours after the onset of AMI, favorable results were obtained for LVEF (44.5 +/- 11.2%) and Tl-DR (1.68 +/- 0.82). The UK group showed as better results as the PTCR + PTCA group for LVEF (42.3 +/- 11.3 vs. 38.1 +/- 7.4) and Tl-DR (2.10 +/- 1.19 vs. 2.09 +/- 0.62). In both the UK and PTCR + PTCA groups, Tl-DR was well maintained despite an increase in the peak CPK and a decrease in LVEF, and, therefore, the conservation of stunned myocardium in the acute stage was suggested. From the above, it was concluded that the UK method is useful for treating AMI.

[The evaluation of left ventricular eccentric hypertrophy by 201Tl-myocardial scintigraphy].

In order to elucidate the mechanism of left ventricular eccentric hypertrophy in conditions of volume overload, Tl-201 myocardial scintigraphy was performed patients with aortic valve regurgitation and mitral valve regurgitation. There was a good relationship between the severity of Tl-defects, as determined by Tl-201 myocardial scintigraphy, and the changes in the T wave on the ECG on the one hand and the NYHA functional classification of heart diseases. In 17 of 18 patients where LVDd increased with increasing severity of Tl-defects and the defects were moderate to severe, LVDd was 65 mm or larger. There was a significant negative correlation between the washout rate for the whole circumference of the left ventricle, as determined by exercise Tl-201 SPECT, and LVDd (r = -0.603, p less than 0.01). The phenomenon of redistribution as determined by exercise Tl-201 myocardial scintigraphy was observed relatively early. Our results suggest that mechanical volume overload and ischemic changes are involved in left ventricular wall damage in left ventricular eccentric hypertrophy. For patients with moderate to severe Tl-defects valve replacement is indicated, no matter whether they may have heart failure or arrhythmia.

[Evaluation of myocardial blood flow and cardiac functional change in acromegaly].

We studied 201Tl myocardial scintigraphy and 99mTc-HSA gated blood pool scan to evaluate the influence of growth hormone on myocardial blood flow and hemodynamics in 16 patients with acromegalies. Contraction properties were almost within normal limit, but cardiac output was in high output state, because left ventricular ejection fraction (LVEF), right ventricular ejection fraction (RVEF) and cardiac output were 47.8 +/- 17.1%, 37.3 +/- 14.9%, and 6.4 +/- 1.7 L/min, respectively. Otherwise, 201Tl myocardial images revealed 62.5% no redistributed hypoperfusion, 18.8% redistributed hypoperfusion, 56.3% myocardial hypertrophy and 25.0% left ventricular enlargement. These data suggested the high incidence of acromegalic cardiomyopathy due to primary or secondary growth hormone effect.

[A case of pulmonary artery aneurysm diagnosed by 99mTc-HSA angiography].

There are not many reports on pulmonary artery aneurysms in Japan. The prognosis of them is unfortunately poor, and surgical treatment should be needed in some cases. We report a case of central pulmonary artery aneurysm diagnosed by 99mTc-HSA angiography.

[Application of straight chain fatty acid analog IPPA [omega-(p-iodophenyl)-pentadecanoic acid] for myocardial imaging--using acute myocardial infarction model].

Application for myocardial imaging and fundamental experiments were studied using straight chain fatty acid analog IPPA [omega-(p-iodophenyl)-pentadecanoic acid]. Biodistribution of IPPA in rabbits (n = 6) shows the accumulation in liver was maintained 81.0% at 30 minutes, while the accumulations of heart, lungs and kidneys were 30.0%, 10.0% and 15.0% respectively. Especially the accumulation of heart decreased rapidly from 48.0% at 3 minutes to 30.0% at 30 minutes, reflecting the effect of beta oxidation. On the other hand, in the acute myocardial infarction mode (n = 6), with occlusion in left anterior descending coronary artery, all 6 cases showed defect images at the corresponding areas after injection of 3 mCi of IPPA. Myocardial imaging with IPPA should be useful not only for myocardial metabolic diseases (cardiomyopathy etc.) but also for ischemic heart disease.

[A case of metastatic lung tumor mimicking left atrial myxoma by echocardiography].

We report a case of lung metastatic tumor originated from submandibular osteosarcoma, which shows rare advancement and findings. This lung metastatic tumor advanced from left lower lung to left atrium through the left lower pulmonary vein, which penetrated to the left ventricle in the diastolic phase mimicking left atrial myxoma. 67Ga-citrate images showed that hot accumulation were recognized behind the heart in planar image and clear advancement from the lung to the heart in the SPECT image. 67Ga-citrate SPECT image should be available for cardiac tumors.

[Evaluation of the visualized left atrium by 201Tl myocardial scintigraphy].

201Tl myocardial scintigraphy was evaluated in patients with 18 mitral stenosis cases. Left atrium was to be seen in ANT (16.7%), LAO (16.7%), MLAO (16.7%) and L-LAT (11.1%), respectively. Furthermore, 201Tl uptake ratio of left atrium, right ventricle, pulmonary area tended significantly to increase in visible group compared with invisible group. PCW pressure was correlated with left atrial Tl uptake (r = 0.51, p less than 0.005), and it indicated some correlation between left atrial pressure and 201Tl uptake.

[Evaluation of cardiovascular responses to handgrip tests in patients with ischemic heart disease by radionuclide method].

Left ventricular responses to handgrip exercise test in patients with ischemic heart disease were assessed by RI methods. We subdivided into three groups (A: delta EF more than 5% increased, B: delta EF -5%-+5% no change, C: delta EF less than 5% reduced), left ventricular contractility (LVEF/LVET) and Tl defect score changed significantly in global EF reduced group, moreover the usefulness of handgrip test was assured. This instrument is low cost, safety, small size, and available for wide ranged ages.

[Evaluation of left atrial function by 99mTc gated blood pool scan].

99mTc gated blood pool scans were studied to assess the left atrial function. Relationship between filling time and rapid emptying time was y = 0.695 x + 109 (r = 0.761, p less than 0.05, n = 14) in LAO and LPO projections. On the other hand, relationship between slow filling and rapid emptying time was good closely (y = 0.846 x + 16.9 (p less than 0.01, r = 0.975, n = 8] in standard and retrograde acquisition. To assess the left atrial function by standard acquisition in LAO projection should be available for clinical use.

[The evaluation of cardiac function and the effect of therapy in acute myocardial infarction--comparison by radio nuclide method in acute and chronic phase].

The cardiac function and the effect of therapy in patients with acute myocardial infarction (AMI) were assessed in over 100 patients by analysis of 201Tl-scintigraphy and 99mTc-gated pool study in our ICU. The cardiac function and 201Tl-defect ratio were compared with the results obtained in chronic phase. Sixteen of them were treated with intravenous urokinase (UK) within 6 hours from onset. The other 18 patients without UK treatment served as a control group. Significant correlation was recognized between 201Tl-defect ratio and peak-CPK levels, peak-GOT levels, peak-LDH levels. Significant correlation (r = -0.655, r = -0.713) were found between 201Tl-defect ratio and LVEF in acute and chronic phase. The UK group showed a significant increase of LVEF as compared with the control group in patients with antero-septal (A/S) AMI. In inferior (INF) AMI, no significant differences were observed UK and control group in LVEF, RVEF and 201Tl-defect ratio. In chronic phase, improvements of LVEF and 201Tl-defect ratio were observed in patients with A/S AMI. But no significant differences of LVEF, RVEF and 201Tl-defect ratio were observed in A/S AMI in acute and chronic phase. The UK group showed a significant increase of LVEF (50.1%) as compared with the control group of A/S AMI in chronic phase. We have demonstrated that a combination of 201Tl-scintigraphy and 99mTc-gated pool study are useful techniques in ICU, to evaluate the cardiac function and the effect of thrombolysis therapy and thus greatly contribute to the primary care of AMI cases.

[Left ventricular wall damage as an indicator for valve replacement in patients with volume overload: a radionuclide study].

Using Tl-201 myocardial single photon emission computed tomography (SPECT), we tried to utilize the Tl-defects to determine the timing for aortic or mitral valve replacement in cases with chronic aortic (AR) or mitral regurgitation (MR), or both. Examinations including echocardiography and angiography were performed to evaluate left ventricular dilatation. Subjects consisted of 80 patients, including 22 with AR, 26 with MR, 17 with AR+MR, and 15 post-operative cases. The Tl-scores (sum of the grade of Tl-defects) correlated well with T wave abnormalities (V5) and NYHA functional class. The scores also correlated with left ventricular end-diastolic dimension (LVDd) and LV ejection fraction (LVEF), indicating that the LV wall defect progressed as the LV dimension increased with the increase in the volume load. Exercise Tl-201 myocardial SPECT revealed redistribution at an early stage of valvular regurgitation, indicating the development of LV wall damage in cases of LV enlargement due to regurgitation. Valve replacement caused a decrease in LVDd, with mild improvement in the Tl-score. We concluded that, in addition to the T wave changes and the echocardiographic measurements, Tl-201 myocardial SPECT should be included in the criteria for valve replacement.

[Effect of hemodialysis on left and right ventricular function--evaluation using electrocardiogram gated radionuclide ventriculography].

Eighteen outpatients with chronic renal failure undergoing hemodialysis (HD) were studied. Immediately before and after HD, the left and right ventricular function measured by electrocardiogram gated radionuclide ventriculography (RNV). By HD, body weight changed 58.6 +/- 7.50 kg to 57.2 +/- 6.80 kg and BUN level changed 67.9 +/- 29.00 mg/dl to 37.1 +/- 18.96 mg/dl and creatinine level changed 11.3 +/- 3.90 mg/dl to 6.8 +/- 2.48 mg/dl. Before HD, cardiac output was 8.08 +/- 1.50 l/min and cardiac index was 5.00 +/- 0.87 l/(min m2). Left ventricular function improved (LVEF changed 60.4 +/- 6.85% to 64.2 +/- 8.7%, LVEF/LVET changed 0.237 +/- 0.048%/ms to 0.254 +/- 0.021%/ms) between before and after HD, but there was not significant difference. Right ventricular function improved (RVEF changed 41.2 +/- 8.00% to 50.0 +/- 11.96, RVEF/RVET changed 0.167 +/- 0.028%/ms to 0.209 +/- 0.059%/ms) between before and after HD, and there was significant difference (p less than 0.05).