Assessment of right ventricular overload by a thallium-201 SPECT study in children with congenital heart disease.

Thallium-201 planar and SPECT studies were performed in 38 children with congenital heart disease using high-resolution three-headed SPECT. The 201Tl total or average right ventricular-to-left ventricular (RV/LV) count ratios were measured by summed short-axis images. In the planar study, the RV/LV systolic pressure ratio correlated with 201Tl RV/LV average count ratio (r = 0.91) better than that in the SPECT study (r = 0.78). However, in the SPECT study, patients with atrial septal defect (n = 9), ventricular septal defect (n = 13), tetralogy of Fallot and double outlet right ventricle (n = 6) showed a characteristic distribution in the plot of RV/LV pressure ratio versus 201Tl RV/LV total count ratio. A prospective study showed that the RV/LV average count ratio was a good predictor of RV/LV pressure ratio (n = 19, r = 0.91). Three-headed SPECT is useful for pediatric cardiac studies, and the overload types found in congenital heart disease seemed to be differentiated by the SPECT study.     

The use and diagnostic significance of thallium-201 SPECT imaging in a case of anomalous left coronary artery

A 6-year-old female with an anomalous left coronary artery (ALCA) originating from the main pulmonary artery underwent a resting Tl-201 SPECT examination before and after surgical reimplantation. Preoperative Tl-201 SPECT images demonstrated decreased perfusion to the anterior wall and a dilated left ventricle. Post operative Tl-201 SPECT images showed marked improvement of perfusion to the anterior wall as well as a decreased left ventricular size. This is one of the few documented demonstrations of a perfusion defect due to an ALCA in a young child using Tl-201 SPECT imaging methods in conjunction with other tests.     

Noninvasive assessment of myocardium at risk by Tl-201 SPECT imaging in a child with Kawasaki disease. A case report.

Serial two-dimensional echocardiograms documented the formation of giant aneurysms, measuring from 0.55 to 3.1 cm in diameter, in the distribution of the left and right coronary arteries, in a 2 1/2-year-old boy with Kawasaki disease. His global left ventricular function, assessed by M-mode echocardiography, was normal, and no significant wall motion abnormalities could be detected on two-dimensinal evaluation. Cardiac catheterization showed multiple aneurysms with no evidence of stenosis. Although he had no clinical symptoms or electrocardiographic evidence of ischemia, pharmacologic stress and delayed Tl-201 SPECT images revealed prominent stress-induced myocardial ischemia in the left ventricle. A resting gated blood pool study showed hypokinesia in corresponding regions of the left ventricle. This case demonstrates the usefulness of Tl-201 myocardial SPECT imaging and resting gated blood pool studies in the management of coronary artery disease in children with Kawasaki disease.     

Exercise-rest Tc-99m tetrofosmin SPECT in patients with chronic ischemic left ventricular dysfunction: Direct comparison with Tl-201 reinjection

BACKGROUND: This study was designed to compare the results of exercise-rest technetium-99m tetrofosmin single photon emission computed tomography (SPECT) with those of thallium-201 reinjection at rest after exercise-redistribution imaging in the same patients with chronic ischemic left ventricular (LV) dysfunction. METHODS: Within 1 week, 33 patients with chronic myocardial infarction and LV dysfunction underwent exercise-rest tetrofosmin SPECT and Tl-201 reinjection at rest after exercise-redistribution imaging. In each patient, regional tetrofosmin and Tl-201 activity was quantitatively measured in 22 myocardial segments. Regional LV function was assessed in corresponding segments by echocardiography. RESULTS: Agreement in the evaluation of regional perfusion status between tetrofosmin and Tl-201 imaging was observed in 78% of the 726 total segments, with a kappa value of 0.61. In segments with normal function at echocardiography (n = 436), no difference between Tl-201 and tetrofosmin uptake was observed. In hypokinetic segments (n = 138), exercise tetrofosmin uptake was lower (P < .01) as compared with exercise Tl-201 activity, whereas no difference was observed between tetrofosmin uptake at rest as compared with Tl-201 activity on redistribution and reinjection images. In segments with severe functional impairment (akinetic or dyskinetic, n = 152), tetrofosmin uptake on exercise images was reduced (P < .01) as compared with exercise Tl-201 activity; furthermore, tetrofosmin uptake at rest was lower (P < .01) as compared with Tl-201 activity on both redistribution and reinjection images. In these segments, concordance in the detection of myocardial viability between tetrofosmin and Tl-201 imaging was observed in 138 (91%) of the 152 segments, with a kappa value of 0.77. CONCLUSIONS: In patients with chronic coronary artery disease and LV dysfunction quantitative exercise-rest tetrofosmin and Tl-201 reinjection SPECT provide similar information in the assessment of perfusion status and in the detection of myocardial viability.     

单发右位心的心血管造影与外科术后诊断对比研究

目的比较单发右位心的心血管造影与外科术后诊断,评价心血管造影诊断结果的准确性,探讨最佳的造影方法及投照体位.方法27例先天性单发右位心病例接受外科姑息性或根治手术治疗,回顾性分析其心血管造影资料（常规左、右室造影,其中8例行选择性心房造影,18例加行双斜位）,根据先天性心脏病节段分析法原则,将其与外科术后诊断进行对比研究.结果心血管造影诊断与外科术后诊断结果对比显示22例诊断基本一致,5例不一致,包括1例解剖校正型大动脉错位误诊为功能校正型大动脉错位,1例完全性大动脉错位误诊为功能校正型大动脉错位,1例单心室误诊为右室双出口（合并心房不定位误诊为心房正位）,2例解剖左室双出口误诊为功能校正型大动脉错位.结论单发右位心并复杂的心血管病畸形,因解剖复杂,在常规行双侧心室造影和正侧位造影基础上加行选择心房造影和双斜位造影,有利于达到准确诊断的目的.     

Computed tomographic angiography in acute pulmonary embolism: do we need multiplanar reconstructions to evaluate the right ventricular dysfunction?

PURPOSE: To compare the indices of right ventricular dysfunction (RVD) obtained from axial transverse images with those derived from the reconstructed 4-chamber and short-axis views in patients with acute pulmonary embolism (PE). MATERIALS AND METHODS: Eighty-eight patients with acute PE were retrospectively enrolled. For each patient, axial transverse images and reconstructed 4-chamber and short-axis views were reviewed. Measurements of the ratios of right ventricle to left ventricle (RV/LV) diameters and RV/LV areas were then obtained from all series. Values derived from each method were compared and correlated to arterial obstruction index. RESULTS: In the studied cohort, RV/LV diameters and RV/LV areas obtained from axial transverse images and the reconstructed 4-chamber views were not statistically different. In contrast, a statistically significant difference was observed between the values of RV/LV areas derived from both axial transverse and 4-chamber views and those obtained from short-axis views (P < 0.0001). There was a weak to moderate correlation between both RV/LV diameters and RV/LV areas and the computed tomographic obstruction index. However, when the study cohort was divided into 3 subgroups with an arterial obstruction index of less than 15% (n = 26), 15% to 30% (n = 21), and greater than 30% (n = 41), those who had values greater than 30% revealed the highest correlation with the indices of RVD. CONCLUSIONS: In patients with acute PE, the indices of RVD derived from axial transverse images and the reconstructed 4-chamber views yield comparative values. Given the simplicity of the former analysis, it should be taken into consideration for risk stratification in acute PE.     

Accuracy of 4 different algorithms for the analysis of tomographic radionuclide ventriculography using a physical, dynamic 4-chamber cardiac phantom.

Various automatic algorithms are now being developed to calculate left ventricular (LV) and right ventricular (RV) ejection fraction from tomographic radionuclide ventriculography. We tested the performance of 4 of these algorithms in estimating LV and RV volume and ejection fraction using a dynamic 4-chamber cardiac phantom. METHODS: We developed a realistic physical, dynamic 4-chamber cardiac phantom and acquired 25 tomographic radionuclide ventriculography images within a wide range of end-diastolic volumes, end-systolic volumes, and stroke volumes. We assessed the ability of 4 algorithms (QBS, QUBE, 4D-MSPECT, and BP-SPECT) to calculate LV and RV volume and ejection fraction. RESULTS: For the left ventricle, the correlations between reference and estimated volumes (0.93, 0.93, 0.96, and 0.93 for QBS, QUBE, 4D-MSPECT, and BP-SPECT, respectively; all with P < 0.001) and ejection fractions (0.90, 0.93, 0.88, and 0.92, respectively; all with P < 0.001) were good, although all algorithms underestimated the volumes (mean difference [+/-2 SDs] from Bland-Altman analysis: -39.83 +/- 43.12 mL, -33.39 +/- 38.12 mL, -33.29 +/- 40.70 mL, and -16.61 +/- 39.64 mL, respectively). The underestimation by QBS, QUBE, and 4D-MSPECT was greater for higher volumes. QBS, QUBE, and BP-SPECT could also be tested for the right ventricle. Correlations were good for the volumes (0.93, 0.95, and 0.97 for QBS, QUBE, and BP-SPECT, respectively; all with P < 0.001). In terms of absolute volume estimation, the mean differences (+/-2 SDs) from Bland-Altman analysis were -41.28 +/- 43.66 mL, 11.13 +/- 49.26 mL, and -13.11 +/- 28.20 mL, respectively. Calculation of RV ejection fraction correlated well with true values (0.84, 0.92, and 0.94, respectively; all with P < 0.001), although an overestimation was seen for higher ejection fractions. CONCLUSION: Calculation of LV and RV ejection fraction based on tomographic radionuclide ventriculography was accurate for all tested algorithms. All algorithms underestimated LV volume; estimation of RV volume seemed more difficult, with different results for each algorithm. The more irregular shape and inclusion of a relatively hypokinetic RV outflow tract in the right ventricle seemed to cause the greater difficulty with delineation of the right ventricle, compared with the left ventricle.     

Interventricular differences in myocardial T2 measurements: experimental and clinical studies.

The goal of this study was to determine the accuracy, the reproducibility, and some of the tissue determinants of image-based myocardial T2 measurements. Image-based T2 calculations for the free walls of the right ventricle (RV) and left ventricle (LV), in vitro T2 determination (at 0.47 T), and water, fat, and collagen content analyses were performed in ex vivo hog hearts. T2 values of the RV and LV free walls were also determined from spin-echo images of 14 healthy human subjects. Preliminary reproducibility studies were performed with 10 sets of images acquired from a single subject. For both in vitro and image-based T2 values of hog hearts, RV T2 was significantly longer than LV T2. Water content was the only tissue factor to significantly correlate with in vitro and image-based T2 values. For the 14 human subjects studied, image-based T2 values calculated from the first- and third-echo images demonstrated a significant difference between LV and RV. The difference was not significant when the first- and second-echo images were used. Image-based T2 measurements of a single subject showed a coefficient of variation of 6.8% for the LV and 9.1% for the RV. The authors conclude that image-based T2 measurements of normal myocardium can be made with sufficient precision to identify differences of the magnitude of those found between RV and LV T2 values. Image-based T2 values of myocardium may provide useful data to aid in patient treatment.     

圆锥动脉干畸形产前超声诊断与误诊分析

目的:探讨产前超声诊断圆锥动脉干畸形的难点及误诊原因分析.方法:对36例胎儿圆锥动脉干畸形的病例资料进行回顾分析,将产前诊断结果与产后新生儿超声心动图或引产后解剖结果进行对比.分析产前诊断结果的偏差,总结产前超声诊断圆锥动脉干畸形的经验.结果:产前超声诊断法洛四联症9例,右室双出口8例,肺动脉闭锁伴室间隔缺损6例,完全型大动脉转位4例,矫正型大动脉转位1例,永存动脉干7例.产前诊断9例法洛四联症中2例产后手术证实为右室双出口,产前漏诊法洛四联症1例,产前诊断符合率70％(7/10);8例右室双出口中2例引产后证实为法洛四联症,产前诊断符合率75％(6/8).6例产前诊断肺动脉闭锁伴室间隔缺损,1例引产后证实为永存动脉干,产前诊断符合率83.3％(5/6);4例完全型大动脉转位,引产后证实全部正确,产前诊断符合率100％(4/4);1例矫正型大动脉转位产后超声心动图证实正确,产前诊断符合率100％(1/1);产前诊断永存动脉干7例,2例引产后证实为肺动脉闭锁伴室间隔缺损,1例引产后证实为主动脉闭锁伴室间隔缺损,产前诊断符合率57.1％(4/7),产前无法分型2例,产前诊断分型符合率50％(2/4).结论:产前超声心动图对圆锥动脉干畸形的检出具有重要的价值,产前超声心动图检查中,认真分析动态图回放、掌握CTA血流动力学改变对提高圆锥动脉干畸形产前诊断准确性有重要意义.     

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.     

Patient motion in thallium-201 myocardial SPECT imaging. An easily identified frequent source of artifactual defect

Because Tl-201 SPECT requires that patients remain in an awkward position for a prolonged time, patient motion is a potentially serious source of artifactual defects on tomographic reconstructions. Thus, a simple method was developed for detection and correction of motion from SPECT images using a Co-57 point source placed on the lower anterior chest, an area remaining in the camera's field of view throughout imaging. In the absence of motion, this point source inscribes a straight line on planar summation of the 32 projections over 180 degrees. Movement is detected by deviation from this line. The number of pixels of motion is used to shift images so that the resultant images of the point source are linear. The method of motion detection and correction was tested in 48 consecutive patients undergoing Tl-201 SPECT. The corrected and uncorrected images were reconstructed and long and short axis tomographic cuts were quantitatively analyzed using circumferential profiles of maximal counts with comparison to the lower limits of normal. Motion was detected in eight of 48 patients (17%). The amount of motion was 2 pixels in three patients and 1 pixel in five patients. Quantitative defect extent was less after correction in seven of eight patients, with a mean decrease of 71% in patients with 2 pixel motion and 44% in patients with 1 pixel motion. This corresponded with a definite reduction in the size of the tomographic defect by visual analysis, and closer resemblance to quantitatively analyzed planar images performed either before or after tomography in the same patient.(ABSTRACT TRUNCATED AT 250 WORDS)     

Tl-201 uptake and retention in a Warthin’s tumor

We report scan findings of Tl-201 in a case of histologically proved Warthin’s tumor. Dual isotopes acquisition was performed in a case of left parotid Warthin’ s tumor. Both early and delayed Tc-99m-pertechnetate (Tc-99m) images showed increased uptake at the tumor. Tl-201 scan also showed an increase of uptake on the early image and retention on the delayed image. The uptake ratios of Tl-201 were 3.0 (early) and 2.3 (delayed). Scan findings of Tl-201 in a case of Warthin’s tumor were similar to those of Tc-99m, and the interpretation of Tl-201 images should be accompanied with Tc-99m images.     

Volumetric cardiac quantification by using 3D dual-phase whole-heart MR imaging

This study was approved by the local institutional ethics committee, and informed consent was obtained from all volunteers and patients. The purpose of the study was to assess ventricular volumes by using three-dimensional (3D) whole-heart data sets acquired during end-systolic and end-diastolic phases during one free-breathing magnetic resonance imaging examination. In five healthy volunteers and 10 patients, 3D dual cardiac phase data sets, short-axis multisection breath-hold images, and through-plane flow images of the great vessels were acquired. Within these data sets, statistic analyses were performed to compare stroke, end-systolic, and end-diastolic volumes for the left ventricle (LV) and the right ventricle (RV). Results showed that the breath-hold multisection approach, the flow measurement approach, and the new dual-phase 3D approach delivered comparable results for quantification of cardiac volumes and function. High correlation values greater than 0.95 were found when these methods were compared, and no significant differences were recognized for stroke, end-systolic, or end-diastolic volumes in either the LV or the RV.     

New method for calculating right ventricular ejection fraction using gated myocardial perfusion studies

BACKGROUND: Quantification of right ventricular ejection fraction (RVEF) is important in patients who have right heart failure or cor pulmonale. When Tl-201 was the primary radiotracer used to evaluate myocardial perfusion, the outline of the right ventricle could vary and was not visualized in most patients. However, visualization of the right ventricle has become easier with the use of Tc-99m-labeled myocardial perfusion agents. PURPOSE: This study describes a new method for quantifying RVEF using gated stress myocardial perfusion (GMP) slices. The results are compared with those of first-pass radionuclide ventriculography (FPRNA) in the same patients. METHODS: Fifty-two consecutive patients referred for routine GMP imaging were included. After administration of Tc-99m tetrofosmin, all patients underwent FPRNA using a single crystal gamma camera and a GMP study. Regions of interest (ROI) were drawn to outline the right ventricular cavity at end diastole and end systole from three pairs of GMP slices. The RVEF was calculated from the number of pixels within the ROIs. The mean RVEF obtained using FPRNA and GMP imaging was 51.8 +/- 10.8% and 51.9 +/- 12.3%, respectively. The two methods showed good correlation with r = 0.81. In addition, there was no significant difference in the RVEFs calculated using these methods (P = 0.85). Bland-Altman analysis also showed good agreement between the two methods (limits of agreement +14.4% to -14.0%, slope = 0.19). Intraobserver and interobserver correlation were evaluated by reanalyzing 12 patients using the new RVEF quantification method and were good at r = 0.87 and 0.82, respectively. Therefore, this is a new convenient method for evaluating RVEF as part of a routine tomographic gated myocardial perfusion study.     

Discordant Tl-201 and Tc-99m imaging in a patient with thyroid carcinoma and Hashimoto's disease

In a case of Hashimoto's disease complicated by thyroid gland cancer, the primary site of the cancer was visualized as a cold nodule on Tc-99m pertechnetate scintigraphy, as a warm nodule on Tl-201 early imaging, and as a hot nodule on Tl-201 delayed imaging. Generally, Tl-201 shows markedly diffuse accumulation in the lesions of Hashimoto's disease. The warm nodules observed on early scans suggested similar accumulation at the sites of Hashimoto's disease and thyroid cancer. The hot nodules on delayed imaging may be due to the difference in Tl-201 washout time between the sites of Hashimoto's disease and thyroid cancer. There was markedly increased Tl-201 accumulation in bilateral cervical metastatic lymph nodes on both early and delayed images.     

ECG-gated thallium-201 myocardial SPECT in patients with old myocardial infarction compared with ECG-gated blood pool SPECT

We evaluated one of the merits of ECG-gated thallium-201 single photon emission computed tomography (g-T1 SPECT), i.e., the ability to appreciate left ventricular (LV) wall motion. LV wall motion assessed by g-T1 SPECT and by ECG-gated Blood Pool SPECT (g-BP SPECT) was classified into three grades and compared segment by segment. T1-201 uptake by g-T1 SPECT was also classified into three grades and compared with those of wall motion in g-BP SPECT. Fifty patients with prior myocardial infarction were injected intravenously at rest with 111 to 185 M Bq (3 to 5 mCi) of Tl-201. The left ventricular regions were divided into anterior, septal, inferior and lateral segments (50 patients X 4 segments = 200 segments in total). The grades of wall motion and Tl-201 uptake detected by g-Tl SPECT correlated well with those of wall motion in g-BP SPECT (94.5% and 85%, respectively). With g-Tl SPECT it was possible to evaluate left ventricular wall motion, providing clear perfusion images.     

Left-sided ventricular cardiomyopathy with minimal right ventricular involvement

Left-sided ventricular arrhythmogenic cardiomyopathy is rare and represents a rather different expression of the arrhythmogenic right ventricular (RV) cardiomyopathy (ARVC). Among sudden cardiac deaths, ARVC plays a significant role. ARVC is considered as a cardiomyopathy of unknown aetiology that primarily involves the right ventricle (RV) and is characterized by progressive replacement of myocytes by fibro-fatty tissue, complicating a spectrum of arrhythmias. Predominant ARVC with left ventricular (LV) involvement is also reported. The LV variant of arrhythmogenic cardiomyopathy with minimal or no RV involvement is rare. A 31-year-old previously healthy young man, without a significant family history, was found dead in bed. Autopsy revealed an enlarged heart and asymmetrical LV hypertrophy with widely patent coronary arteries. LV myocardium demonstrated evidence of prominent epicardial fibro-fatty tissue that is predominantly fatty in nature and infiltrates into the myocardium. Microscopy of the LV free wall showed fibro-fatty tissue infiltration into the epicardial aspect of the LV that extends well into the mid-myocardium. A moderate to marked degree of interstitial fibrous tissue deposition was noted about adipocytes and cardiomyocytes. There was no evidence of chronic ischaemic changes or of significant myofibre disarray. The RV showed minimal fibro-fatty infiltration with normal myocytes. This report highlights a rare case which confirms previous observations that the LV variant of arrhythmogenic cardiomyopathy could occur with minimal or no involvement of the RV. Further studies are required in this context to elicit the spectrum and the exact nature of this disease.     

A new method for crosstalk correction in simultaneous dual-isotope myocardial imaging with Tl-201 and I-123

We have developed a new method of crosstalk correction in simultaneous dual-isotope imaging with Tl-201 and I-123 by using crosstalk ratios and a blurring filter. Single isotope myocardial studies (10 for Tl-201 and 7 for I-123) were performed with a dual energy window acquisition mode and two low energy general-purpose collimators. Then two planar images acquired with dual energy windows for a Tl-201 line source and an I-123 line source were obtained to measure line spread functions (LSFs) and crosstalk ratios for each image. The line source experiments showed that the LSFs for the Tl-201 imaging window from the single Tl-201 source were very similar to those for the I-123 imaging window from the single Tl-201 source, but the LSFs for the Tl-201 imaging window from the single I-123 source had broad shapes which differed from those for the I-123 imaging window from the single I-123. To obtain accurate I-123 crosstalk images in the Tl-201 imaging window from the I-123 images in the I-123 imaging window, we designed a low-pass blurring filter. In 7 clinical I-123 MIBG studies, I-123 window images processed with this filter became very similar to the Tl-201 window image from the single I-123 source. The method proposed in this study can accurately correct the crosstalk in dual isotope studies with Tl-201 and I-123 and is easily applicable to conventional gamma camera systems with any dual energy window acquisition mode.     

Tl-201 thyroid imaging in differentiating benign from malignant thyroid nodules

To evaluate the value of Tl-201 thyroid imaging in differentiating benign from malignant thyroid nodules, 58 patients with histologically proven thyroid masses were studied. The nature of the thyroid tumor was initially assessed by Tc-99m scans. Early and delayed Tl-201 thyroid imaging were performed in all patients, and thallium uptake and clearance in the cold nodules were assessed visually. Of the 20 patients with histologically proven malignant nodules, 19 showed increased Tl-201 activity in both the early and delayed images, indicating a sensitivity of 95%. On the other hand, 35 out of the 38 patients with benign nodules showed no increased thallium activity in the nodules on the delayed images, indicating a specificity of 92%. When early thallium images were analyzed separately, the sensitivity was 100% but the specificity was only 37%. By combining early and delayed Tl-201 images, differentiation between benign and malignant cold nodules is feasible. False-positive and false-negative cases will be discussed.     

Serial assessment of left ventricular function in various patient groups with Tl-201 gated myocardial perfusion SPECT

Purpose The present study was performed to assess stress-related left ventricular (LV) function variations in various patient groups and to determine if they were affected by sex or the type of stress experienced. We used thallium (Tl)-201 gated myocardial perfusion single-photon emission computed tomography (SPECT) for the analysis. Materials and methods A total of 270 patients were examined by electrocardiography-gated myocardial perfusion SPECT imaging to assess LV function. After injection of Tl-201 at a dose of 111 MBq at peak stress, SPECT scans were acquired at 10 min (after stress) and 3 h (rest) after injection on a three-headed camera. Results In the normal perfusion group, the mean LV ejection fraction (LVEF) was significantly higher, and both the end-diastolic volume index (EDVI) and end-systolic volume index (ESVI) were significantly lower in women than in men (P < 0.05). Poststress stunning occurred in 29 of 98 patients (30.0%) in the ischemia group and in 42 of 90 patients (46.7%) in the fixed group. There was a significant difference in poststress stunning between bicycle ergometer stress and dipyridamole stress (P < 0.05). Conclusion In patients with normal perfusion, LVEF, EDVI, and ESVI determined by gated Tl-201 SPECT should be corrected for sex. In addition, the influence of the type of stress should be considered when assessing stress-related LV function variations.