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ABSTRACT: The effect of exercise on the cardiac kinetics of 123I-MIBG was investigated in the present study. 123I-MIBG was administered intravenously at rest in 6 healthy male volunteers, and anterior planar and SPECT images were obtained 15 minutes, and 2 and 4 hours after administration (protocol A). After 4 weeks, 123I-MIBG was again administered intravenously at rest, and images were obtained 15 minutes later. After imaging, the subjects ran 10 km in approximately 1 hour, and anterior planar and SPECT images were obtained 2 and 4 hours after administration of 123I-MIBG (protocol B). The heart-to-mediastinum uptake ratio (H/M) was calculated from each anterior planar image, and the mean 123I-MIBG clearance from 15 minutes to 2 hours, and from 2 hours to 4 hours was calculated with a bull's eye display. The H/M was much lower after exercise. The mean clearance rate between 15 minutes and 2 hours in protocol B was significantly higher than that between 2 hours and 4 hours, and that between 15 minutes and 2 hours in protocol A. It was concluded that the clearance rate of 123I-MIBG may be a useful index of cardiac sympathetic nerve activity.
Annals of Nuclear Medicine 09/1998; 12(4):175-8. · 1.50 Impact Factor
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ABSTRACT: Myocardial sympathetic nerve function can be evaluated by 123I-metaiodobenzylguanidine (MIBG) scintigraphy. Congestive heart failure is closely related to myocardial sympathetic nerve function. This study evaluated the severity of congestive heart failure in 30 patients with valvular heart disease [aortic regurgitation (AR): n = 20, mean age = 70 +/- 13 years; mitral regurgitation (MR): n = 10, mean age = 61 +/- 18 years], who had chronic heart failure by MIBG myocardial scintigraphy. Single photon emission computed tomography (SPECT) and anterior planar myocardial images were obtained 15 minutes (initial images) and 4 hours (delayed images) after injection of MIBG (111MBq). Defect score was determined by the delayed SPECT images visually as a semi-quantitative index. Myocardial MIBG uptake was quantified by the heart to upper mediastinum uptake ratio on the delayed anterior planar images (H/M) and mean cardiac MIBG washout rate during 4 hours was calculated from the bull's eye display data (clearance). These indices were compared with the NYHA class and echocardiographic findings of the patients. MIBG regional defect in the delayed image was most frequently seen in the inferoposterior wall, and defect score and clearance were significantly higher and the H/M ratio was significantly lower in NYHA class III patients than in class II patients. In patients with AR, clearance significantly correlated with left ventricular end-systolic dimension. In patients with MR, both the H/M ratio and clearance significantly correlated with left atrial dimension. Defect score, H/M, and clearance were closely related to the severity of AR and MR. These results indicate that MIBG scan can be used to assess the severity of valvular heart disease.
Journal of Cardiology 06/1995; 25(5):247-53. · 1.28 Impact Factor
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ABSTRACT: 201TlCl (Tl), 123I-beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP) and 123I-metaiodobenzylguanidine (MIBG) images were applied before and after PTCA to a patient with acute coronary syndrome who had repeated ischemic attacks on light effort. A decreased tracer uptake was noted at the mid and apical anteroseptal regions in each image before PTCA. MIBG uptake was most decreased and Tl uptake was least decreased, but Tl uptake at exercise decreased as severely as MIBG uptake at rest. After PTCA an uptake was improved in each image. Both before and after PTCA, the area with decreased BMIPP uptake corresponded to the region with deteriorated wall motion obtained by echocardiography. It was suspected that the decreased MIBG uptake correlates with "area at risk" and that the decreased BMIPP uptake correlates with abnormal wall motion. Taken together those findings, it was indicated that an application of these cardiac scintigraphy is useful for the evaluation of comprehending metabolic abnormality and recovering process of ischemic myocardium.
Kaku igaku. The Japanese journal of nuclear medicine 01/1994; 30(12):1459-63.
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ABSTRACT: 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy was performed in twelve normal human subjects, and the distribution and clearance of MIBG were estimated. In PLANAR studies, heart to mediastinum (H/M) and lung to mediastinum activity ratio (L/M) were 2.68 +/- 0.45 and 1.82 +/- 0.23 in initial images, and 2.75 +/- 0.44 and 1.55 +/- 0.13 in delayed images. The clearance of MIBG in the lung was more rapid than that in the heart, 41.6 +/- 4.1 vs. 29.8 +/- 3.2 (%), therefore MIBG cardiac profiles were more clarified in delayed images. In SPECT studies, the regional relative uptake (RRU) in anterior, septal, inferior and lateral wall were 100.0 +/- 0, 93.9 +/- 6.9, 85.0 +/- 10.0 and 104.9 +/- 8.3 (%) in initial images, and 100.0 +/- 0, 96.8 +/- 9.6, 79.4 +/- 8.3 and 99.1 +/- 7.9 (%) in delayed images, respectively. The RRU in inferior wall was significantly lower than those in the other walls. The regional clearance rate (RCR) in these four walls were 25.1 +/- 4.6, 22.5 +/- 8.2, 29.7 +/- 8.3, 29.3 +/- 3.4 (%), respectively. The RCR in inferior and lateral wall were significantly larger than those in anterior and septal walls. The RRU in basal, mid and apical portion were 100.0 +/- 0, 104.5 +/- 3.3, 98.9 +/- 12.1 (%) in initial images, and 100.0 +/- 0, 103.9 +/- 4.5, 96.8 +/- 15.2 (%) in delayed images, respectively. The RRU in mid portion was significantly higher than that in basal portion.(ABSTRACT TRUNCATED AT 250 WORDS)
Kaku igaku. The Japanese journal of nuclear medicine 12/1993; 30(11):1359-67.
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ABSTRACT: Effect of verapamil on myocardial ischemia in patients with hypertrophic cardiomyopathy (HCM) was evaluated by exercise stress myocardial 201Tl SPECT (EX-Tl). EX-Tl were performed before and after 8.8 weeks of oral verapamil (240 mg/day) in 12 patients with HCM who showed transient 201Tl perfusion defects under control conditions. 201Tl perfusion defect was visually scored and judged for 4 grades as normal (0), mild defect (1), moderate defect (2), and severe defect (3). Transient Dilation Index (TDI) was calculated as an index of subendocardial ischemia. Improvements of defect score were demonstrated in 10 patients after administration of verapamil. Two patients showed no change of defect score. Mean defect score decreased significantly from 5.50 to 3.03 (p < 0.001). Although 11 of 12 patients showed abnormal TDI under control conditions, 10 of them revealed improvements of TDI and 7 of those 10 patients disclosed normal TDI after verapamil. Mean TDI decreased from 1.263 to 1.090 significantly (p < 0.01). In conclusion, verapamil may improve myocardial ischemia in patients with HCM.
Kaku igaku. The Japanese journal of nuclear medicine 02/1993; 30(1):69-73.
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ABSTRACT: There has been no report that Accelerated Idioventricular rhythm (AIVR) causes a syncope attack. The patient described in this report is very rare because AIVR chronic without any heart diseases has been observed for 13 years, and because it is considered that AIVR is closely associated with his repeated blackouts. A 62-year-old male was admitted to our hospital because of repeated syncopal attacks. He reported that he occasionally felt lightheaded after strenuous lifting and pushing or pulling against resistance. We found that AIVR could produce a remarkable arterial pressure drop partly because of ventricular asynergy and loss of timed atrial contribution. Furthermore, we observed syncopal attacks during Valsalva maneuver and found abnormalities of baroreceptor reflex (Lack of reflex tachycardia and weakened evershoot phenomenon). It is concluded that AIVR is not a benign arrhythmia in this patient because it has been a possible cause of syncope attack due to systemic arterial pressure drop and baroreceptor abnormalities.
Kokyu to junkan. Respiration & circulation 08/1992; 40(7):699-703.
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ABSTRACT: 123I-BMIPP myocardial scintigraphy was performed in 13 patients with hypertrophic cardiomyopathy and compared with 201Tl myocardial scintigraphy performed within 3 months for evaluating the clinical significance of 123I-BMIPP myocardial scintigraphy. SPECT images were divided into 13 segments and segmental images were visually scored on a 4 (increased tracer uptake) to 0 (severely decreased tracer uptake) scale according to the tracer uptake. In comparison of 123I-BMIPP early images and 201Tl perfusion images, mismatches were seen in about 70% of all segments. The number of segments demonstrating lower myocardial uptake of 123I-BMIPP was larger than that of 201Tl. In hypertrophic regions, the tracer uptake of 123I-BMIPP early images was significantly lower than that of 201Tl images and the lower uptake of 123I-BMIPP delayed images was more marked. In non-hypertrophic regions, no significant difference was seen between the tracer uptakes of 123I-BMIPP early images and 201Tl images but the tracer uptake of 123I-BMIPP delayed images was significantly lower than that of 201Tl images. The mismatch between the tracer uptakes of 123I-BMIPP images and 201Tl images was thought to be a reflection of disordered myocardial fatty acid metabolism. "Washout", the difference between the tracer uptakes of 123I-BMIPP early images and delayed images was also thought to be a reflection of disordered myocardial fatty acid metabolism. These results suggest that 123I-BMIPP is a promising radiopharmaceutical for evaluating disordered myocardial fatty acid metabolism in patients with HCM.
Kokyu to junkan. Respiration & circulation 03/1992; 40(2):175-81.
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ABSTRACT: Patients with hypertrophic cardiomyopathy (HCM) are known to have ischemic events and decreased coronary flow reserve, but the variabilities in the site and degree of fall between patients with this disease have not been clarified. To elucidate these variabilities, we performed exercise myocardial single photon emission computed tomography (SPECT) using double dose method in 30 patients with HCM (6 with obstruction, 17 with non-obstruction, 7 with apical hypertrophy) and 10 normals. Then, the delta Fract (coronary flow reserve index) map was obtained for each subject. Exercise and then rest Tl-201 myocardial scintigraphy were performed after administration of Tl-201. The data were reconstructed, making the circumferential curves from the same level of short-axis imaging during exercise and at rest. By subtracting the values at rest from the values during exercise, which were divided by the values at rest, delta Fract in each frame was obtained, and described on the unfolded map. The extent and degree of coronary flow reserve were visually estimated by this delta Fract map. Patients were categorized into 5 groups: diffuse fall of coronary flow reserve (D-type), 6 cases; localized fall of the septum or lateral wall (L-type), 5 cases; fall of apical region (A-type), 5 cases; mild fall (M-type), 6 cases; and normal pattern (N-type), 8 cases. We concluded that delta Fract map is useful for evaluating the extent and degree of coronary flow reserve in HCM.
Journal of Cardiology 02/1992; 22(1):123-30. · 1.28 Impact Factor
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ABSTRACT: A case of aortic valve stenosis without coronary artery disease was confirmed to have diffuse subendocardial ischemia by exercise Thallium-201 myocardial single photon emission computed tomography. A 72-year-old woman, who had been diagnosed as aortic valve stenosis, was admitted because of chest pain during exercise. In cardiac catheterization findings, the patient angiographically had normal coronary arteries and no asynergy of left ventricular wall motion. The peak flow velocity in continuous wave Doppler echocardiography was about 5.0 m/sec at aortic valve level, providing a pressure drop of 100 mmHg across a stenotic valve with calculating on a modified Bernoulli equation (PG = 4V2). Thallium-201 myocardial SPECT images during exercise showed a transient "dilation and a widespread wall thinning" of left ventricle with apical perfusion defect. Simultaneous electrocardiogram showed further ST depression and the patient had chest pain. In 6 months after aortic valve replacement the patient no longer demonstrated both apical perfusion defect and "wall thinning" in postoperative thallium-201 myocardial SPECT images and also had neither ST depression nor chest pain. Thus; a transient "dilation and wall thinning" of left ventricle in this patient is suspected to be a sign of diffuse subendocardial ischemia.
Kaku igaku. The Japanese journal of nuclear medicine 02/1992; 29(1):97-103.
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ABSTRACT: With Thallium-201 (Tl) myocardial scintigraphy, right atrial (RA) myocardium has been visible in the disease involving the right side of the heart. We have found RA visualization in the elderly patients without the evidence of right heart disease. Therefore, we studied the relation of age to the RA visualization with Tl myocardial scintigraphy performed at rest. Planar images of 291 patients without valvular or congenital heart disease were read by two observers and classified into the three by the degree of RA visualization; RA 0 = not visualized, RA 1+ = moderately visualized, RA 2+ = intensely visualized. The results were as follows: 93.1% of under 50 y.o., 77.8% of fifties, 86.7% of sixties, 50.5% of seventies and 36.7% of over 80 y.o. showed RA 0. 6.9% of under 50 y.o., 22.2% of fifties, 8.3% of sixties, 46.5% of seventies and 36.7% of over 80 y.o. showed RA 1+. None of under 60 y.o., 5.0% of sixties, 3.0% of seventies, and 26.6% of over 80 y.o. showed RA 2+. In conclusion, RA visualization in Tl myocardial scintigraphy, suggesting right heart overload, may increase with aging.
Kaku igaku. The Japanese journal of nuclear medicine 11/1991; 28(10):1173-6.
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ABSTRACT: We examined whether recurrent transient ischemia may effect left ventricular systolic and diastolic function or not. Left ventricular systolic and diastolic function during the asymptomatic period was studied by gated radionuclide ventriculography (RNV) in 25 patients with vasospastic angina (VA) who had no significant coronary stenosis, in 25 patients with effort angina (EA), and in 20 controls (C). There was no significant difference among patients in all three groups in regards to systolic indices (Ejection Fraction, Peak Ejection Rate). But diastolic indices (Peak Filling Rate, Time to Peak Filling Rate, 1/3 Mean Filling Rate, 1/3 Filling Fraction) were impaired not only in patients with EA but also in patients with VA. The treatment with nitrates and/or Ca antagonist for 6-24 months did not bring about any changes in these data concerning systolic and diastolic function in patients with VA. Thus, it is suggested that the diastolic function is impaired in patients with VA even during the asymptomatic period, though systolic function remains normal. Recurrent transient ischemia may cause irreversible myocardial injury.
Kokyu to junkan. Respiration & circulation 10/1991; 39(9):899-903.
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ABSTRACT: The pattern of Thallium-201 reverse redistribution (r-RD) at rest has been reported in some patients with acute myocardial infarction (AMI) in the acute phase. But there is no report of this pattern in the later phase. To investigate the significance of Thallium-201 reverse redistribution in the subacute phase, 37 patients with AMI underwent Thallium-201 SPECT at rest a month after the onset. The patients were classified into three groups visually and 19 of 37 patients (51%) showed the persistent defect pattern (Group PD), and the remaining 18 patients (49%) had the reverse redistribution pattern (Group r-RD). None of them had the redistribution pattern. Coronary reflow was earlier and the incidence of the scintigraphic overlap on Dual SPECT image of 99mTc-PYP/201TlCl in the acute phase was more frequent in Group r-RD than in Group PD. A decrease in thallium defect size of patients with r-RD from the acute phase to one month after the onset represented improvement more significantly than that with PD. Initial %Tl uptake of the infarcted region of Group r-RD was greater than that of Group PD. The degree of stenosis of the infarct-related coronary artery in Group r-RD was less severe than that in Group PD. And corresponding regional wall motion of Group r-RD was less impaired. The Thallium-201 washout in the infarcted region with r-RD was significantly faster than that in the normal region. It is concluded that the r-RD pattern at rest in the 1st month after the onset of AMI may be a sign of viable myocardium.
Kaku igaku. The Japanese journal of nuclear medicine 08/1991; 28(7):749-57.
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ABSTRACT: Pathophysiology and clinical significance of a systolic backward flow in the epicardial coronary artery have not been elucidated. Using a 20 MHz Doppler catheter, we assessed coronary flow velocity waveforms in the left anterior descending coronary artery in 19 patients with hypertrophic cardiomyopathy (HCM) and 11 patients without apparent cardiac abnormalities as control subjects. Systolic flow fraction was smaller in HCM than in controls. Only 4 patients with HCM showed a prominent retrograde flow persisting during almost the entire systole. All the 4 had marked cavity obliteration and two of them had systolic intraventricular pressure gradients of 80 and 110 mmHg respectively. Exercise thallium-201 ECT revealed that myocardial hypoperfusion was more frequent in those 4 patients. Through these observations, it is concluded that a high intramyocardial systolic pressure combined with a relatively low coronary perfusing pressure may result in a large systolic retrograde flow in the left epicardial coronary artery, and that it may be related to myocardial ischemia in patients with HCM.
Kokyu to junkan. Respiration & circulation 03/1991; 39(2):169-74.
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ABSTRACT: Exercise Tl scintigraphy (EX-Tl) provides a noninvasive means of identifying myocardial perfusion abnormalities in patients (pts) with hypertrophic cardiomyopathy (HCM). We have noted that some pts with HCM have a pattern of transient dilation of the left ventricle (LV) on the immediate post exercise images as compared with 3 hour redistribution images. We presumed that left ventricular dilation was caused by subendocardial hypoperfusion. So we studied transient dilation of the LV in 50 pts with HCM and 20 controls (C). Initial and delayed conventional short tomographic images were obtained after reconstruction of 30 projections acquired over 180 degrees. Thirty six radii every 10 degrees were generated from the center of the middle myocardial images of the short axis. An area surrounded by the thirty six points of maximal count on each radius was calculated in initial and delayed images. Transient Dilation Index (TDI) as an index of dilation was determined by dividing an area in initial image by an area in delayed image. TDI in pts with HCM was larger than that in C. Pts with HCM were classified into the two groups, Group A: TDI greater than 1.11 (mean + 2 SD in C), 24 pts, Group B: TDI greater than 1.11, 26 pts. Frequency of pts with history of chest pain in Group A was higher than that in Group B, and frequency of pts with positive exercise ECG in Group A was higher than that in Group B. End diastolic volume in Group B did not change 10 minutes after exercise by radionuclide ventriculography. In conclusion, transient dilation of the LV in pts with HCM by EX-Tl is in appearance, and may reflect subendocardial ischemia.
Kaku igaku. The Japanese journal of nuclear medicine 12/1990; 27(11):1281-9.
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ABSTRACT: Previous observations suggest the presence of ischemia in the disproportionately thickened interventricular septum (IVS) of patients with hypertrophic cardiomyopathy (HCM), although the details remain obscure. Utilizing digital subtraction coronary angiography (DSA) with LAO projection before and after intracoronary papaverine (P) injection, we evaluated regional myocardial coronary blood flow reserve (rMFR) consecutively 18 patients with HCM, and compared it with that of 8 patients without apparent cardiac abnormality (C). Time-density curves were obtained from digital angiograms of the myocardial region of interest. We measured peak contrast density (Cm) and time to peak contrast (Tm). An index of rMFR was calculated as the quotient of Cm/Tm before and after P. In HCM, rMFR in IVS and apex was significantly lower than that of C (Mid-IVS: 1.9 +/- 0.5 vs 3.9 +/- 0.5, p less than 0.001; Low-IVS: 2.0 +/- 0.5 vs 4.4 +/- 0.9, p less than 0.001; Apex: 2.0 +/- 0.7 vs 4.5 +/- 1.6, p less than 0.01). There was correlation between the impairment of rMFR and the extent of hypertrophy in HCM. In conclusion, we could state that, in HCM, the region of impaired myocardial coronary blood flow reserve is localized. In HCM, DSA is useful in evaluating myocardial coronary blood flow reserve.
Kokyu to junkan. Respiration & circulation 11/1990; 38(10):1021-7.
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ABSTRACT: Myocardial imaging with Xenon-133 and a gamma camera was employed to evaluate the relationship between angiographically demonstrated coronary artery stenosis and regional myocardial blood flow (r-MBF) in 22 patients with ischemic heart disease and 9 control subjects. After a left anterior oblique cineangiogram was obtained, the cinecamera was replaced by the mobile gamma camera in the same plane and location over the pericardium of patients. Then, 370 MBq (10 mCi) of 133Xe was injected into the left coronary artery as a bolus. After the first measurement of r-MBF in resting state, a second injection was made 3 minutes after intravenous injection of 0.56 mg/kg of dipyridamole for 4 minutes. The r-MBF in different regions of the heart was calculated by Kety formula. Coronary flow reserve (CFR) was defined the rMBF ratio between resting and dipyridamole induced vasodilative state. In the resting state, good correlation (r = 0.711) was observed between pressure rate product and the r-MBF at the areas perfused by non stenotic vessels. The r-MBF of the areas perfused by severe stenotic vessels (greater than 90%) was smaller than that of the areas perfused by non stenotic vessels, however there was overlapping of flow. In the dipyridamole induced vasodilative state, the r-MBF of the areas perfused by intact vessels increased approximately 2.4 times of the resting state, and showed good correlation with pressure rate product. In contrast, the r-MBF of the areas perfused by stenotic vessels did not correlate with pressure rate product, but depended on the degrees of coronary stenosis (50-75% stenosis; 1.9 times, greater than 90% stenosis; 1.3 times, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
Kaku igaku. The Japanese journal of nuclear medicine 07/1990; 27(6):639-47.
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Kaku igaku. The Japanese journal of nuclear medicine 03/1990; 27(2):165-72.
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ABSTRACT: To assess viability of the infarcted myocardium, we performed stress Tl-201 myocardial scintigraphy using reinjection method in 37 patients with old myocardial infarction, and in 13 patients of them, Tl myocardial imagings were performed in resting state on the other day within 4 weeks after this examination. In this method, 111 MBq (3 mCi) of thallium was injected at the peak of exercise and initial and delayed images were acquired, then additionally 37 MBq (1 mCi) of thallium was injected after delayed scanning (reinjection) and we obtained post-reinjection images. Delayed images showed redistribution in 15 patients (41%), and no redistribution in 22 patients (59%). In post-reinjection images, 7 (19%) of 15 patients with redistribution and 3 (8%) of 22 patients without redistribution showed improvement of thallium uptake, in total 10 patients (27%) had additional thallium uptake in infarcted regions. And the degree of thallium uptake in post-reinjection images were almost equal to that in resting images. In conclusion, myocardial imaging using thallium reinjection method may be useful for the assessment of viability of the infarcted myocardium.
Kaku igaku. The Japanese journal of nuclear medicine 02/1990; 27(1):39-43.
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ABSTRACT: We investigated whether peak filling rate (PFR) obtained from ECG gated radionuclide ventriculography (RNV) reflects left ventricular (LV) relaxation rate or not. Five patients with angina pectoris, 5 patients with old myocardial infarction and 6 controls were studied by simultaneous acquisition of RNV and LV pressure. RNV was performed in modified left anterior oblique position before and during angiotensin II (A II) infusion to elevate their blood pressure about 25 mmHg (A-1) and 50 mmHg (A-2). The data were acquired in a list mode and LV volume curves were reconstructed by forward and backward gating from the R wave of ECG. Actual PFR and corrected PFR by stroke volume (/SV), by end diastolic volume (/EDV), by instantaneous volume (/IV) were calculated from LV volume curve and its first differential curve. LV pressure was simultaneously measured by the catheter-tip micromanometer, and the time constant (T) of assumed exponential decline in LV pressure was calculated as index of LV relaxation rate. Although there was no correlation between actual PFR and T, corrected PFR (/EDV) and PFR (/IV) correlated with T. PFR (/EDV) decreased and T increased during A-1 and A-2. Decrease of PFR (/EDV) corresponded with increase of T. Thus, corrected PFR (/EDV) obtained from RNV reflects the rate of LV relaxation, and was considered to be an useful index to evaluate LV diastolic function.
Kaku igaku. The Japanese journal of nuclear medicine 01/1990; 26(12):1493-501.
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ABSTRACT: To evaluate the myocardial perfusion during transient coronary occlusion, we attempted to obtain the myocardial scintigraphy during percutaneous transluminal coronary angioplasty (PTCA). Tl-201 was injected at the last inflation of angioplastic balloon and occlusion was kept on for 60 sec. Planar images or SPECT were obtained immediately after PTCA. With this protocol, myocardial perfusion defects were observed during PTCA and fully redistributed 3 hours after Tl injection. Extent of ischemic lesions were almost same as that observed during exercise in two cases without collateral vessels. In a case with well visualized collateral vessels, perfusion defect was smaller in PTCA images than that in exercise stressed images. We conclude that intravenous injection of Tl-201 during PTCA is useful to assess the alteration of myocardial perfusion due to transient coronary occlusion without increasing the risk of angioplastic procedure.
Kaku igaku. The Japanese journal of nuclear medicine 01/1990; 26(12):1545-8.
