Assessment of left ventricular function by 201Tl ECG-gated myocardial SPECT]

We applied the QGS program for LV function analysis (described by Germano, 1995) to a 201Tl SPECT study at rest, and estimated its accuracy. We performed 201Tl ECG-gated myocardial SPECT in 25 patients with ischemic heart disease under an acquisition time used in the routine 99mTc ECG-gated SPECT study. The quality of the gated images was visually assessed with a 4-point grading system. LVEDV, LVESV, LVEF determined by the QGS program were compared with those by Simpson's method on biplane LVG in 25 patients. Regional wall motion scores in 7 myocardial segments were assessed on the three-dimensional display created by the QGS program and the cine display of biplane LVG with a 5-point grading system. Wall motion scores obtained by the QGS program were compared with those by LVG. Although 72.0% of 201Tl ECG-gated SPECT images were fair or poor in image quality, there were good correlations between the values obtained by the QGS program and LVG (LVEDV: r = 0.82, LVESV: r = 0.88, LVEF: r = 0.89). In addition, wall motion scores by the QGS program were correspondent to those by LVG in 77.1% of all 175 myocardial segments. We conclude that the QGS program provides high accuracy in evaluating left ventricular function even from 201Tl ECG-gated myocardial SPECT data.     

Characteristics of Tl-201 myocardial SPECT images of patients with coronary artery lesion of diagonal branch

Noninvasive detection of coronary artery lesion of diagonal branch is important. Utility of Tl-201 myocardial SPECT images for this purpose was studied in 9 patients with angina pectoris and 4 patients with myocardial infarction, in whom localized stenosis more than 75% was noted at diagonal branch. Position of basal margin of abnormal region in the coronal images lay between -30 degree and 30 degree and basal abnormal region was very narrow. Width of mid portion of abnormal region lay from 5 degree to 70 degree. Abnormal region due to diagonal branch was not noted in septal region. These results showed the utility of Tl-201 myocardial SPECT images for detecting coronary artery lesion of diagonal branch.     

Assessment of myocardial viability with 201Tl myocardial SPECT 24 hours after injection]

Recently many investigators reported that conventional stress-redistribution myocardial scintigraphy with 201Tl underestimated the presence of ischemic but viable myocardium. We studied the usefulness of 24 hour 201Tl myocardial single photon emission computed tomography (SPECT) to assess myocardial viability and investigated the factors affect to the quality of 24 hour SPECT images. Study patients were consisted with 70 patients with old myocardial infarction (OMI), 72 patients with angina pectoris without OMI (AP) and 43 patients with angiographically proven normal coronary arteries. To obtain SPECT images, 10 minute and 4 hour imagings were sampled 30 seconds per projection. Twenty-four hour imaging was sampled 60 seconds per projection. Twenty-four hour images were visually interpreted as good, moderate and poor quality. Then study patients were divided into 2 groups, group A with good 24 hour images and group B with moderate or poor 24 hour images. One hundred and fifty-eight patients (85.4%) of study patients had 24 hour SPECT images on a good quality. Only 4 patients (2.2%) had poor quality SPECT. All of these 4 patients had broad myocardial infarction. In patients with OMI 61 patients (87.1%), in AP 63 patients (87.5%) and in normal 35 patients (81.4%) had a good 24 hour SPECT. Total sampling counts and myocardial ROI counts were significantly higher in group A than in group B. Body weight was significantly higher and there were more male patients in group B than in group A. Late redistribution was seen in 20 patients (28.5%) with OMI and in 11 patients (15.3%) with AP.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of infantile ventricular tachycardia by 201Tl myocardial SPECT]

201Tl myocardial SPECT findings in infantile ventricular tachycardia (VT) were examined. The subjects were 4 cases of infantile VT subjected exercise-loading 201Tl scintigraphy in 1990. These cases (3 males and 1 female) were aged 11-14 years, being persistent and non-persistent type VT (2 cases each). Echocardiography revealed no abnormal findings in these 4 cases. Exercise-loading was performed by means of sitting ergometer. ECG revealed sinus arrhythmia except for one case which throughout its course of treatment, had already been presenting ventricular extrasystole from before the exercise-loading. Myocardial SPECT revealed persistent defects (anteroseptal wall defects in three case). The above suggests that 201Tl myocardial SPECT enables us to search for etiology of VT, prognosis and the like.     

Intra-patient reproducibility of myocardial SPECT imaging with 201Tl

Background  To define the physical and clinical reproducibility of ²⁰¹Tl myocardial perfusion SPECT (MPS), this study assesses the variation between two repeated rest ²⁰¹Tl MPS with repositioning only, with a two-hour time interval and with phantom measurements as a reference. Methods  Three anthropomorphic thorax phantoms were filled with ²⁰¹Tl. For each phantom five repeated ²⁰¹Tl MPS were obtained. In addition, in 20 patients repeated ²⁰¹Tl rest-MPS and in 26 patients early and delayed ²⁰¹Tl rest-MPS were performed. Quantitative analysis was done using MunichHeart. Statistical methods were used to calculate variability. Visual analysis was performed by 2 independent observers. Results  The average variation between repeated phantom MPS was 0.5% (95% confidence interval (CI): −0.4% to 1.4%). For patient scans this was −5.0% (95% CI: −2.5% to −7.5%) and between early and delayed ²⁰¹Tl MPS −15.5% (95% CI: −11.7% to −19.3%). Visual assessment revealed no clinical significant differences between rest ²⁰¹Tl and repeated or delayed ²⁰¹Tl MPS. Conclusions  Repositioning in phantom ²⁰¹Tl MPS does not cause significant variation. Repeated ²⁰¹Tl MPS in patients shows 5.0% decrease of ²⁰¹Tl in 30 minutes, which increases to 15% during a two-hour time interval without quantitative or visual regional differences. This decrease indicates a time-related washout of ²⁰¹Tl, but does not change clinical diagnosis.     

Specific perfusion pattern in stress 201Tl myocardial scintigraphy of left main coronary artery disease

The usefulness of stress 201Tl myocardial scintigraphy for identifying left main coronary artery disease was evaluated with data from 23 patients with 50% or more narrowing of the left main coronary artery and 56 patients with 75% or more narrowing of the major coronary arteries but without left main coronary artery involvement (no left main coronary artery disease). Quantitative evaluation of stress perfusion scintigrams in all five patients with narrowing of the left main coronary artery of 90% or more showed a characteristic perfusion pattern (left main pattern) of extensive homogeneous defect over the whole anterolateral segment and simultaneous defects in all radii of the high anteroseptal and high posterolateral segments. On the other hand, such a perfusion pattern was noted in only 1 of 18 patients with less than 90% stenosis of the left main coronary artery and in only 1 of 56 patients with no left main coronary artery disease.     

Specific perfusion pattern in stress 201Tl myocardial scintigraphy of left main coronary artery disease

The usefulness of stress ²⁰¹Tl myocardial scintigraphy for identifying left main coronary artery disease was evaluated with data from 23 patients with 50% or more narrowing of the left main coronary artery and 56 patients with 75% or more narrowing of the major coronary arteries but without left main coronary artery involvement (no left main coronary artery disease). Quantitiative evaluation of stress perfusion scintigrams in all five patients with narrowing of the left main coronary artery of 99% or more showed a characteristic perfusion pattern (left main pattern) of extensive homogeneous defect over the whole anterolateral segment and simultaneous defects in all radii of the high anteroseptal and high posterolateral segments. On the other hand, such a perfusion pattern was noted in only 1 of 18 patients with less than 90% stenosis of the left main coronary artery and in only 1 of 56 patients with no left main coronary artery disease     

Comparison of the myocardial distributions of 201Tl and 99Tcm-MIBI on SPECT images

The distributions of 201Tl and 99Tcm-MIBI on stress images were quantitatively measured in a series of 15 patients presenting with documented coronary artery disease. Following two sequential, one-week apart, peak-exercise injections of either 74 MBq of 201Tl or 370 MBq of 99Tcm-MIBI, tomographic views of the myocardium were reconstructed and two thick, central short-axis sections were divided into nine sectors. A sector was considered as showing a defect if its relative activity was lower than 30, 40, 50 or 60% of the highest level of activity in the 18 sectors. Results demonstrate that there were more defects with 201Tl than with 99Tcm-MIBI. However, the difference disappeared if the inferior wall was not included. These results suggest that depth attenuation could be, at least partly, responsible for the higher rate of positive results observed in single photon emission computed tomography with 201Tl than with 99Tcm-MIBI.     

ATP负荷~(201)Tl心肌断层显像对冠心病的诊断价值

目的　评价ATP负荷2 0 1Tl心肌断层显像用于冠心病患者诊断的可行性和临床价值。方法　静脉注入ATP 0 .14mg·kg-1·min-1共 3min ,之后注射2 0 1Tl 148MBq ,10min和 3～ 4h后分别作心肌断层显像。结果　ATP负荷2 0 1Tl心肌断层显像诊断冠心病的灵敏度为 88% ,特异性为 90 %。ATP注入后引起的副作用轻微而短暂。结论　ATP负荷2 0 1Tl心肌断层显像用于诊断冠心病有较高的准确性     

定量门控201Tl心肌显像对冠心病患者的预后价值

目的 研究定量门控201Tl心肌显像对冠心病患者预后评估及冠心病治疗方案选择的价值.方法 对84例患者进行静息和运动负荷201Tl门控心肌灌注SPECT显像,并随访(32.92±16.77)个月.对心肌灌注图像进行评分(1～4分),计算总负荷评分(SSS)、总静息评分(SRS)和总差值分(SDS=SRS-SSS)、负荷左室射血分数(EF)值和静息EF值.结果 随访中9例发生心脏事件,年发生率为3.90%.SSS、SDS、SRS以及EF值均是心脏事件的独立预测因素(P＜0.005).Cox比例风险回归分析示SSS是心脏事件的最强预测因素.根据患者的负荷后EF值、SDS等可将患者分为低危、中危和高危组.结论 应用定量门控201Tl心肌显像可以对冠心病患者进行正确的预后评估,并可指导选择治疗方案.SSS是心脏事件的最强预测因素.     

Utility of rest Tl-201 myocardial SPECT images for estimating myocardial viability]

Rest Tl-201 myocardial SPECT images were underwent in 19 patients with anterior wall myocardial infarction under PTCR one month after the onset of acute myocardial infarction. The relationship between shortening rate (SR) of the left ventricle estimated by radial method and corresponding %Tl-201 uptake obtained by circumferential profile analysis was studied. For each patients 10 points on the anterior wall were taken into consideration. Seven patients showed depressive flat profile curve and 12 patients showed slant curve, in which %Tl-201 uptake continuously decreased from base to apex. Well correlation was obtained between SR and %Tl-201 uptake (SR = -41.2 +/- 1.03% Tl-201 uptake, r = 0.54, p less than 0.001). Average %Tl-201 uptake corresponding to SR = 0 was 46.3 + 6.8% (36-58). The sensitivity of %Tl-201 uptake greater than or equal to 60% for SR greater than or equal to 20% was 97% (87/90) and specificity was 69% (31/45). Tl-201 myocardial SPECT images were useful for estimating myocardial viability and %Tl-201 uptake was one of excellent parameters for quantitatively estimating myocardial viability.     

扩张型心肌病患者双嘧达莫负荷心肌201Tl SPECT显像分析

目的 观察扩张型心肌病患者的双嘧达莫负荷心肌201Tl SPECT显像表现.方法 2008年8月至2009年12月临床符合扩张型心肌病诊断标准的住院患者30例,按体质量0.56 mg/kg给予其双嘧达莫,于4 min内静脉注射,2 min后注射201Tl,注射完后10及240 min分别进行双嘧达莫负荷心肌201Tl SPECT显像,图像经三维重建后由2位以上有经验的核医学科医师进行分析.结果 27例(90.00%)患者的双嘧达莫负荷201Tl图像(10 min)显示左心室心肌放射性分布异常.延迟(240 min)显像时所有患者均出现左室心肌放射性分布异常,其中6例患者出现"反向再分布".结论 双嘧达莫负荷心肌201Tl SPECT显像对指导扩张型心肌病的诊治具有一定的临床意义.     

扩张型心肌病患者双嘧达莫负荷心肌^201Tl SPECT显像分析

目的 观察扩张型心肌病患者的双嘧达莫负荷心肌201Tl SPECT显像表现.方法 2008年8月至2009年12月临床符合扩张型心肌病诊断标准的住院患者30例,按体质量0.56 mg/kg给予其双嘧达莫,于4 min内静脉注射,2 min后注射201Tl,注射完后10及240 min分别进行双嘧达莫负荷心肌201Tl SPECT显像,图像经三维重建后由2位以上有经验的核医学科医师进行分析.结果 27例（90.00%）患者的双嘧达莫负荷201Tl图像（10 min）显示左心室心肌放射性分布异常.延迟（240 min）显像时所有患者均出现左室心肌放射性分布异常,其中6例患者出现＂反向再分布＂.结论 双嘧达莫负荷心肌201Tl SPECT显像对指导扩张型心肌病的诊治具有一定的临床意义.     

Assessment of myocardial viability by resting 201Tl SPECT image

The aim of this study was to assess whether resting 201Tl scintigraphy is superior in detecting viable myocardium than previous conventional methods. We performed not only stress 201Tl SPECT but also resting 201Tl SPECT within one month in 65 patients with coronary artery disease. Resting 201Tl images were quantitatively compared with 4 hour late images of stress study using a polar map. In stress study, redistribution was recognized on 83% (25/30) of non-MI SEGs with perfusion defect in the stress 201Tl image, and on 39% (18/46) of infarcted SEGs. The agreement of resting 201Tl study with 4 hour late images of stress study was shown on 93% (28/30) of non-MI SEGs and on 52% (24/46) of MI SEGs. The increased uptake of 201Tl in resting study, however, was found on 13 (46%) of 28 MI SEGs showing fixed defects in stress study. In stress delayed image with fixed defect, the %Tl uptake of improved SEGs was higher than that of unchanged SEGs (59 +/- 10% vs 48 +/- 11%; p greater than 0.05). There was no viable myocardium which had %Tl uptake less than 40% at stress delayed image. In conclusion, the resting 201Tl imaging will give an important information as for the myocardial viability showing fixed defects, if more than 40% Tl uptake is observed.     

双嘧达莫负荷心肌201Tl SPECT显像诊断冠状动脉微循环障碍的价值

目的 探讨双嘧达莫负荷心肌201Tl SPECT显像在诊断冠状动脉微循环障碍中的价值.方法 选取临床符合心脏X综合征诊断标准的患者共48例,按患者体质量0.56mg/kg予双嘧达莫针剂静脉注射(4min),在心脏负荷达高峰后注入201Tl 111 MBq,10min及240min后分别进行心肌201Tl SPECT显像,原始图像经三维重建后由2位以上有经验的核医学科医师进行分析.对出现“反向再分布”现象的患者采用山莨菪碱(654-2)治疗2周后,再次进行双嘧达莫负荷心肌201TlSPECT显像,同时比较患者治疗前后临床症状和平板运动试验结果.结果 48例患者中有42例延迟(240min)显像时均显示部分心肌节段反向放射性分布稀疏或缺损,即“反向再分布”,检出阳性率为87.50％(42/48).在42例出现“反向再分布”现象的患者中,治疗后临床症状及平板运动试验结果均有改善的36例患者再次进行延迟(240min)显像时原受累的49个节段中有45个节段放射性分布有不同程度改善,检出阳性率达91.84％(45/49).两者有1项未改善或2项均未改善的6例患者延迟(240min)显像时原受累的7个节段放射性分布无改善.结论 双嘧达莫负荷心肌201Tl SPECT显像对诊断以心脏X综合征为代表的冠状动脉微循环障碍疾病有一定的价值.     

Cost-effectiveness of exercise 201Tl myocardial SPECT in patients with chest pain assessed by decision-tree analysis]

To evaluate the potential cost-effectiveness of exercise 201Tl myocardial SPECT in outpatients with angina-like chest pain, we developed a decision-tree model which comprises three 1000-patient groups, i.e., a coronary arteriography (CAG) group, a follow-up group, and a SPECT group, and total cost and cardiac events, including cardiac deaths, were calculated. Variables used for the decision-tree analysis were obtained from references and the data available at our hospital. The sensitivity and specificity of 201Tl SPECT for diagnosing angina pectoris, and its prevalence were assumed to be 95%, 85%, and 33%, respectively. The mean costs were 84.9 x 10(4) yen/patient in the CAG group, 30.2 x 10(4) yen/patient in the follow-up group, and 71.0 x 10(4) yen/patient in the SPECT group. The numbers of cardiac events and cardiac deaths were 56 and 15, respectively in the CAG group, 264 and 81 in the follow-up group, and 65 and 17 in the SPECT group. SPECT increases cardiac events and cardiac deaths by 0.9% and 0.2%, but it reduces the number of CAG studies by 50.3%, and saves 13.8 x 10(4) yen/patient, as compared to the CAG group. In conclusion, the exercise 201Tl myocardial SPECT strategy for patients with chest pain has the potential to reduce health care costs in Japan.     

Discrepancy between myocardial ischemia and luminal stenosis in patients with left internal mammary artery grafting to left anterior descending coronary artery

BACKGROUND: Left internal mammary artery (LIMA) grafting to the left anterior descending artery (LAD) is known to have long-term patency. However, myocardial ischemia in the territories supplied by LIMA to LAD is still demonstrated. The aim of this study is to examine the relationships between the extent, location, and clinical outcome of myocardial ischemia in LAD territories (ILAD) by use of myocardial perfusion imaging (MPI) and angiographic characteristics of such a bypass conduit. METHODS AND RESULTS: We studied 38 consecutive patients with prior coronary artery bypass grafting who showed stress-induced ischemia in LIMA to LAD territories by MPI single photon emission computed tomography between the years 1996-2000. All patients underwent quantitative coronary angiography within 6 months of the nuclear study. Single photon emission computed tomography parameters of ILAD were assessed by location (septum, apex, anterior, and anterolateral) and included extension score (1-4 per patient), severity score (0-3 per territory), and total sum score. LIMA to LAD quantitative coronary angiography parameters included minimal lumen diameter, lesion length, reference diameter, and diameter stenosis (percentage). LAD and LIMA diameters and ratio (in normal segments) were determined within 10 mm proximal and distal to the anastomotic site. The study group was compared with 18 control subjects without ischemia or stenosis treated with LIMA to LAD. The patients were followed up for cardiac death at an interval of 3.2 +/- 1.5 years from the time of MPI testing. The patients' mean age was 66 +/- 12 years (31 men and 7 women); the mean period after surgery was 6.2 +/- 1.5 years. The ILAD distribution was as follows: septum, 12 (32%); apex, 20 (52%); anterior, 24 (63%); and anterolateral, 18 (47%). The mean extension score was 1.9 +/- 1.0, and the mean total sum score was 3.4 +/- 2.3. Of 38 patients with ILAD, only 17 (45%) had greater than 50% luminal stenosis (2 LIMA and 15 anastomosis or distal). Among clinical variables during stress testing, the prevalence of angina was significantly higher in the luminal stenotic patients versus patients without stenosis (P =.04). A significant correlation was found between anterior wall ischemia and reference diameter (r = -0.7, P =.002) and between total sum score and minimal lumen diameter (r = -0.48, P =.05). Of note, the LAD-to-LIMA ratio was significantly lower in patients with ILAD and without luminal stenosis compared with the control group (0.73 +/- 0.16 vs 0.87 +/- 0.15, P =.004). Cardiac death occurred in 8 patients (21%), 5 patients with luminal stenosis versus 3 patients without stenosis (P = not significant). CONCLUSIONS: In patients with LIMA to LAD anastomosis, myocardial ischemia could occur even without angiographic luminal stenosis and apparently reflects a mismatch between LAD and LIMA diameters at distal anastomotic sites. Regarding the similar prevalence of cardiacdeath, invasive evaluation and aggressive treatment are recommended in all patients with ischemia in LIMA/LAD territories.