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The phase III clinical trial of strontium-89 chloride agent (SMS.2P) was performed in 90 patients with painful bone metastases secondary to prostate (53), breast (18) and other types of cancer (19). Some patients experienced a transient increase in pain or nausea and vomiting. However both symptoms subsided and serious side effects were not observed in any of the patients. As reported, we confirmed some abnormal changes in peripheral blood picture. A decrease in the number of white blood cells and platelets was considered to be partly a result of bone marrow suppression due to 89Sr irradiation. Pain was substantially improved after 89Sr therapy in 58% of the patients and there was some alleviation in 12%. The release from pain was accompanied by an improved quality of life for these patients including sleep patterns and morbidity. Some patients were able to resume their former life styles. Most of the improved patients experienced pain relief from days to one week following 89Sr therapy and in half cases, this remained effective for 2 or 3 months. There were even cases in which the pain relief continued over an observation period of time of clinical study.

We evaluated regional cerebral blood flow in the hippocampus in 21 patients with neurological disorders by 99mTc-ethyl cysteinate dimer (ECD) SPECT and compared the findings with those by 123I-N-isopropyl-p-iodoamphetamine (IMP) SPECT. In all subjects, SPECT was taken using ECD (740 MBq) and IMP (167 MBq) using high performance SPECT (3-head SPECT, Toshiba GCA-9300A/HG) within 3 weeks interval. Regional uptake in the hippocampus was examined in the coronal sections and images parallel to the longitudinal axis of hippocampus. ECD and IMP showed similar hippocampal uptake in 9 cases, but ECD showed less uptake than IMP in 12 cases (57%). Regional counts in the hippocampus were related to the counts in the lateral temporal cortices and the mean count ratio was lower in ECD by 8.8% than that in IMP (0.73 +/- 0.11 vs. 0.80 +/- 0.11, p < 0.001). In 6 patients suspected to have hippocampal lesion (4 cases of memory disturbance and 2 cases of epilepsy), all cases showed decreased uptake of ECD in hippocampus, but only 3 cases showed decreased uptake of IMP. This is suggestive to be relevant to the difference in the retention mechanism of ECD and IMP, but further investigation should be performed.

Cerebrovascular stroke is one of the major complications in cardiovascular surgery with cardiopulmonary bypass. The purpose of this study was to evaluate the usefulness of preoperative 99mTc-ethyl cysteinate dimer (ECD) SPECT and acetazolamide (diamox) enhancement to predict neurological complications in cardiovascular surgery. Eighteen patients with coronary disease, valvular disease or aortic aneurysm were studied before the operations. Regional cerebral blood flow and perfusion reserve were evaluated using ECD SPECT before and after the intravenous administration of diamox (1 g). Three cases with moderate to severe baseline abnormalities and poor perfusion reserve had cerebral infarction postoperatively. Twelve cases with good to fair perfusion reserve had no neurological complication. Three cases having poor perfusion reserve had the operations with more intensive brain protection, in which higher perfusion pressure to the brain was maintained during cardiopulmonary bypass, and no neurological complication was observed. In conclusion, patients who have moderately or markedly abnormal baseline flow with poor perfusion reserve may have some risk of neurological complications in cardiovascular surgery. ECD SPECT with diamox enhancement may give information useful for selection of operation procedures.

Myocardial perfusion and fatty acid metabolism may be unpaired in the patients of vasospastic angina (VSA), because abnormal regional wall motion of left ventricle has been shown in some cases of VSA without apparent history of myocardial infarction. To study the clinical utility of 123I-BMIPP scintigraphy in diagnosis of myocardial ischemia in VSA, both 123I-BMIPP (rest) and 201T1 (exercise) SPECT were performed in the 20 patients of VSA diagnosed by coronary angiography. Defect scores were calculated visually from the 17 segments of myocardial images and were compared with patient's anginal history, period from last attack, numbers of attack, left ventricular (LV) ejection fraction and severity of regional LV wall motion abnormality. 123I-BMIPP SPECT images showed decreased tracer uptake in 14 cases of 20 (70%) VSA patients. Exercise 201T1 SPECT images showed decreased tracer uptake in 3 cases of 20 (15%) of patients. Severity of regional LV wall motion abnormality was correlated with defect score of BMIPP. Though total defect score of BMIPP did not correlate with patient's anginal history, number of symptoms and LV ejection fraction, correlated inversely with period from last attack. It was suggested that 123I-BMIPP myocardial SPECT images in VSA patients showed "memories" of myocardial ischemic damages induced by vasospasm. In summary, 123I-BMIPP myocardial SPECT images could be a useful test for diagnosis and evaluation of VSA.

The aim of this study was to elucidate the characteristic feature of myocardial imaging with 123I-labeled 15-(p-iodophenyl)-3R,S-methylpentadecanoic acid (BMIPP) in the patients with hypertrophic cardiomyopathy (HCM). In 26 patients with asymmetric septal hypertrophy (ASH), the imaging data were acquired for 15 minutes after the injection of 123I-BMIPP by the emission computed tomography (ECT). ECT image was divided into 17 segments to score the severity of the defect in each segment using a 5-point grading system from score 3 to score -1; score 3 = severely decreased tracer uptake, score 2 = moderately decreased tracer uptake, score 1 = mildly decreased tracer uptake, score 0 = normal and score -1 = increased tracer uptake. Reduced uptake (Defect Score > or = 2) was frequently observed in septal portion of anterior wall (65%), septal portion of posterior wall (62%) and apical wall (73%). Defect score was higher in septal portion of anterior wall (p < 0.001), septal portion of posterior wall (p < 0.01) and apical wall (p < 0.01) than in the ventricular septum. This result indicates that in hearts with ASH, 123I-BMIPP image reveals severely impaired fatty acid metabolism in these regions. With the reference of the previous report about histologic features in necropsy hearts with HCM, myocardial fatty acid metabolic disorder shown by reduced 123I-BMIPP uptake is closely related to the histological abnormalities in hearts with HCM.

To establish a basis for semiquantitative SPECT measurements of the D2 dopamine receptor density using equilibrium analysis, we evaluated in vivo kinetic properties of 125I-IBZM in rat brains. We measured percent uptakes (% dose/g) of 125I-IBZM in the striatum, frontal cortex, and cerebellum. We made these regional measurements at 15, 30, 45, 60, 90, and 120 minutes after injection, respectively. The specific striatal uptake, which is the uptake difference between striatum and frontal cortex or cerebellum, showed a transient equilibrium phase at 60 min. Theoretically, with these 'reversible' D2 receptor binding ligands, the tracer-uptake ratio of the striatum-to-frontal cortex or cerebellum during the equilibrium phase provides an estimate of binding potential (Bound/Free = Bmax/Kd). Our experiment showed that these ratio increased with time after bolus injection of the tracer. Striatum to frontal cortex or cerebellum ratios which were calculated with pooled data (n = 12) at 60 minutes in equilibrium phase showed nearly constant values (C.V. = 12.3% and 13.5%, respectively). Although measuring the striatum to frontal cortex or cerebellum ratios near equilibrium phase by bolus injection of the tracer which are widely used in human SPECT study could not exactly signify the binding potential, those ratios at fixed time after injection would be reliable for semiquantitative index.

123I-(S)-(-)-3-iodo-2-hydroxy-6-methoxy-N-[(1-ethyl-2-pyrrolidinyl) methyl]-benzamide (IBZM) is a CNS dopamine D2 receptor imaging agent for SPECT and has already been used clinically in the United States, Canada and Europe. However, methods of quantitative SPECT measurement of the D2 receptor density have not been well established. We performed in vivo biodistribution studies of 125I-IBZM in rat brains as the first step toward establishment of a basis for quantitative SPECT imaging of D2 receptors in humans. 125I-IBZM was prepared by the chloramine-T method. Radiochemical yields were 80 to 90% and radiochemical purity was 94.7% on day 81 after labeling. At 10, 30, 60 and 120 min after injection of the radiopharmaceutical, the percent uptakes (% dose/g) in the rat striatum were 2.9, 1.9, 1.7 and 1.0, respectively. These kinetic data were considered suitable for SPECT imagings. Pretreatment with haloperidol (1 mg/kg) blocked specific striatal uptake and there was a significant reduction in the uptake to 40.9% of the unblocked uptake at 60 min after injection (p = 0.006). The regional IBZM uptake ratio of striatum-to-cerebellum increased steadily from 1.7 at 10 min to 5.7 at 120 min. This suggests that SPECT imaging must be done during fixed time after tracer injection for the semiquantitative ratio to be meaningful.

Hypertrophic cardiomyopathy (HCM) is known to have the impairment of myocardial perfusion as well as irregularly hypertrophic myocardium. To evaluate myocardial perfusion and ventricular shape in HCM, 99mTc-Tetrofosmin scintigraphy was performed after exercise (Ex) and at resting state (Re) in 10 patients with HCM and was compared with early image (Ea) and delayed image (De) of 201Tl scintigraphy performed after exercise. SPECT images of both 99mTc-Tetrofosmin and 201Tl scintigraphy were analyzed with five scaled visual scores set in 18 segments. The complete concordance ratio between 99mTc-Tetrofosmin (Ex and Re) and 201Tl (Ea and De) images in segmental analysis was 75%. Image quality of 99mTc-Tetrofosmin was seemed to be superior to that of 201Tl scintigraphy. In 9 patients with HCM, 99mTc-Tetrofosmin scintigraphy was performed under the ECG gating and the thickness of septal and free wall was measured. Good correlation was observed with the data by ultrasound cardiography (r = 0.79, p < 0.002 in wall thickness, r = 0.84, p < 0.01 in the ratio of septal wall thickness to free wall thickness). Left ventricular shape (ventricular long axis) was closely resemble to that of left ventriculography by contrast medium. In conclusion, 99mTc-Tetrofosmin scintigraphy is useful for the evaluation of myocardial morphology as well as perfusion abnormality.

Recent studies have demonstrated that some underestimation of myocardial viability remained to be not resolved even using reinjection method. So we devised a new technique of reinjection and reimaging, and using this we studied the detectability of myocardial viability in 32 patients of CAD. Exercise imaging (EX) was acquired after initial injection of thallium (111 MBq). Three hours after EX, the second dose thallium (37 MBq) was reinjected, and then the first reinjection image (Re1) was performed. Furthermore, the second reinjection image (Re2) was obtained at 3 hours after the second dose reinjection. SPECT images were divided in basal, mid and apical parts, and totally 13 segments were analyzed by visual scoring (0: severe, 1:moderate, 2:mild hypoperfusion and 3:normal). Twenty-seven (13.4%) of 202 segments of low score (0 to 2) shown in EX were improved in Re2, compared with Re1. Twenty-one (42.0%) of 50 segments of score 0 or 1 shown in Re1 were improved in Re2. These results showed that our devised new method of reimaging 3 hours after the second dose injection was useful to improve in detectability of myocardial viability.

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.

Fourteen patients with chronic renal failure (CRF) were studied by dipyridamole 201Tl myocardial scintigraphy. In this study, patients with coronary heart disease were excluded by clinical findings. 201Tl SPECT was performed at 8 min after injection of dipyridamole (0.56 mg/kg) and at a 3-hr delayed interval, and washout rates (WR) were calculated. Because UCG showed left ventricular hypertrophy (thickness; 13 +/ 2 mm) in CRF, the WR values were compared with those of hypertrophic cardiomyopathy (HCM) (n = 9). In CRF, an average WR was 54.2 +/- 6.8% and was significantly higher than that in normal (46.2 +/- 9.1%, p < 0.05, n = 9), though WR in HCM was significantly low (26.9 +/- 11.4%, p < 0.01). Hematocrit value was 24.5 +/- 3.2% in CRF and was significantly lower than that in normal (37.8 +/- 3.6%, p < 0.001). On the other hands, hemoconcentration was observed in HCM (hematocrit; 44.6 +/- 3.6%, p < 0.001). WR in CRF, HCM and normal had significant correlation with hematocrit values (r = -0.796, p < 0.001). These results suggest that anemia or hemoconcentration may affect coronary blood flow and WR, and this should be considered when diagnosing coronary heart disease in CRF or HCM.

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)

Reverse redistribution is revealed on exercise 201Tl myocardial SPECT in some cases with hypertrophic cardiomyopathy. Ten patients with hypertrophic cardiomyopathy without coronary artery disease who showed reverse redistribution visually were studied. Reverse redistribution was evaluated by the early and delayed images of exercise 201Tl myocardial SPECT. Relation between reverse redistribution and distribution of left ventricular hypertrophy estimated by echocardiography and magnetic resonance imaging was investigated, and the mechanism of reverse redistribution was analyzed by referring to Bull's eye display of washout rate. Reverse redistribution was displayed in non-hypertrophic region and washout rate was normal in that region and low in hypertrophic region. In conclusion, in order to interpret reverse redistribution it is necessary to recognize hypertrophic region and to refer to washout rate.

Phase II clinical study of mercaptoacetylglycyl-glycylglycinate (99mTc) technetium (99mTc-MAG3), a new scintigraphic and renographic agent, was performed to evaluate its safety, clinical usefulness and optimal dosage at 5 institutions in total 88 patients with mild renal or urinary disorders. There was no case showed adverse reaction in patients studied and the administration of the agent was proved to be safe. The effectiveness of the agent was evaluated and revealed to be effective in all cases analyzed. A range of dosage 200-400 MBq was found to be optimal, from image quality and clinical information obtained. It is concluded that 99mTc-MAG3 is a safe and useful radiopharmaceutical for the diagnosis of renal dynamic function.

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.

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.

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.

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.

Right ventricular function at rest and during exercise was studied in 33 patients with mitral valve disease by equilibrium gated radionuclide angiography using 99mTc in vivo labeled red blood cells. Radionuclide measurements of right ventricular ejection fraction (RVEF) were correlated with mean pulmonary arterial pressure (mPAP). RVEF decreased significantly with exercise. There was no significant correlation between RVEF at rest and mPAP. However, mPAP showed significant negative correlation with RVEF during exercise and with the changes of RVEF from rest to exercise. It is concluded that RVEF during exercise in mitral valve disease is affected by right ventricular afterload, and the measurements of RVEF at rest and during exercise by equilibrium gated radionuclide angiography is useful to assess right ventricular afterload.

Image quality of dynamic single photon emission computed tomography (SPECT) using a rotating gamma camera is dependent on the time activity variation of the tracer such as accumulation and excretion in the object's organ. Especially at the early time after injection of radionuclide, artifacts may occur strongly in the SPECT images. Simulated and experimental projection data of line sources and Jaszczak phantom were altered by sequentially weighting the projections with a function that varied linearly with time. With a variation of object activity given by linearly decaying functions, the main effect observed on the SPECT images obtained from simulated line sources was an elliptical deformation on the object. If the changing rate (R (t + 1)-R(t))/R(t) x 100 remained within 20% during acquisition, this deformation of SPECT images of line sources was not noticeable visually and resolution (FWHM) of line sources scarcely was degraded. In renal dynamic SPECT study using 99mTc-DTPA, the image quality of the first scan (30 sec) was considerably degraded. However, the changing rates after the third scan were less than 20% on the mean of 10 kidneys and the image quality was not noticeable visually.

Intrahepatic shunt ratio was calculated from the fraction of the uptake constant and the blood background, analyzing the data of 99mTc-(Sn)-N-pyridoxyl-5-methyltryptophan (99mTc-PMT) hepatobiliary imaging by Rutland method. Shunt flow and total hepatic blood flow (THBF) were also calculated from the values for the effective hepatic blood flow (EHBF) estimated from the blood clearance technique. In 15 cases of normal volunteer, the average of the shunt ratio, shunt flow, and THBF were 18.4 +/- 5.4 (S.D.)%, 137.8 +/- 49 ml/min, and 753 +/- 83.2 ml/min, respectively. In 8 cases of chronic hepatitis, the values were 35.2 +/- 2.6%, 276 +/- 55.4 ml/min, and 794.1 +/- 119.4 ml/min, respectively. In 12 cases of liver cirrhosis, the values were 51.4 +/- 12.6%, 353.9 +/- 141.3 ml/min, and 685.6 +/- 174.8 ml/min, respectively. In cases of chronic hepatitis and liver cirrhosis, in comparison with normal cases, the values for the shunt ratio and shunt flow were significantly increased (p less than 0.001) and those for EHBF were significantly decreased (p less than 0.001), but those for THBF were not significantly altered. There was a significant inverse correlation between the shunt ratio and EHBF (r = -0.842) in all 35 cases. This method is considered to be useful for differential diagnosis, estimation of the grade of the diseases, and evaluation of pathophysiology of various diffuse liver diseases.

131I-Metaiodobenzylguanidine (MIBG) is now accepted as a useful agent for the diagnosis of adrenal medullary tumor. The aim of this paper is to evaluate 131I-MIBG for the assessment of the biological activity of residual or recurrent tumor after initial treatment in patients with neuroblastoma. Nineteen scans were performed for 9 patients, mean age 3.5 years-old. Computed tomography demonstrated paravertebral mass in six and metastatic liver tumor in four cases. Anterior and posterior images of the thorax and abdomen were taken 48-72 hours after injection of 7.4-18.5 MBq (0.2-0.5 mCi) 131I-MIBG. Positive images were obtained in 8 scans for four patients and followed by rapid growth of tumor and increased urinary dopamine. The biological activity of residual or recurrent tumor was thought to be high in these patients. Eleven scans for 5 patients revealed negative. In four of them, the tumor size reduced and urinary dopamine value remained within normal limits on the follow-up study. The tumor was assumed to have low biological activity in these patients. One case in which initial scan was negative became positive on the follow-up study. 131I-MIBG activity did not well correlate with urinary vanillylmandelic acid as compared with urinary dopamine. In conclusion, 131I-MIBG proved to be useful for assessing biological activity of residual or recurrent tumor of neuroblastoma and estimating the prognosis of the patient.

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.

123I-Metaiodobenzylguanidine (MIBG) is expected to be useful agent for functional evaluation of the myocardial sympathetic innervation. The aim of this paper is to investigate serial change of 123I-MIBG myocardial concentration in patients (pts) with dilated cardiomyopathy (DCM) as compared with 201Tl uptake. Eight pts with DCM and six non-cardiac subjects (controls) were examined. After injection of 111 MBq (3mCi) 201Tl and 111 MBq (3 mCi) 123I-MIBG, simultaneous myocardial imaging in anterior view was performed for both tracers in every 30-60 minutes during 5 hours (6 images). Myocardial uptake ratio per pixel to the injected dose was calculated for each tracer with background and cross-talk correction on each image. In pts with DCM, myocardial uptake ratio of 123I-MIBG did not differ significantly from that of controls. The washout of 123I-MIBG from the myocardium, however, was significantly increased in pts with DCM as compared with controls. The % decrease of the radioactivity in 3 hours was 46.9 +/- 13.8% in DCM, whereas 18.0 +/- 7.7% in controls (p less than 0.05). Especially, the decrease in the early phase (less than 1 hour) was significantly larger in DCM than controls (21.2 +/- 7.5% vs 5.3 +/- 4.0%, p less than 0.01). For 201Tl, on the other hand, neither uptake ratio nor washout rate, differed significantly between the two. In conclusion, the rapid washout of 123I-MIBG in the early phase may reflect some sympathetic dysfunction in pts with DCM.

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)

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.

Midventricular hypertrophy (MVO) is a rare and complicated myocardial disease. Its pathophysiology and prognosis remain unknown, and few nuclear cardiological findings for MVO were reported. On a 44-year old man with MVO, thallium-201 (Tl) myocardial scintigraphy and gated blood pool scintigraphy (GPS) were performed to evaluate their usefulness. GPS revealed a characteristic hour-glass deformity of the left ventricular cavity, apical aneurysm and asynchrony due to obliteration of the midventricle. Anteroseptal hypertrophy in midventricle and myocardial damage in apico-inferior region were detected by Tl. Thus, nuclear cardiological studies are proved to be useful and essential in not only diagnosis but also evaluating pathophysiology and observing natural history noninvasively.

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.

To evaluate right ventricular (RV) systolic and diastolic properties in patients with various heart diseases, RV volume curves obtained from 81mKr scintigraphy with continuous infusion were analyzed. The data were acquired in right anterior oblique position for five minutes, and from RV time activity curve and its first derivative curve, ejection fraction and peak ejection rate as systolic indices, and peak filling rate, time to peak filling and 1/3 mean normalized diastolic filling rate as diastolic indices were calculated. Ejection fraction in patients with dilated cardiomyopathy was lower than that in controls, but there was no difference in systolic indices among controls and patients with the other heart diseases. However, diastolic indices in patients with hypertrophic cardiomyopathy, patients with hypertensive heart disease, patients with dilated cardiomyopathy, patients with inferior myocardial infarction, and some patients with anteroseptal myocardial infarction were lower than those in controls. In conclusion, analysis of RV time activity curve by 81mKr scintigraphy with continuous infusion provides RV systolic and diastolic indices, which may permit evaluation of RV systolic and diastolic properties in various heart diseases.