Thallium-201 Myocardial Imaging Research Articles

Long-term prognostic value of computed tomography-based attenuation correction on thallium-201 myocardial perfusion imaging: A cohort study.

BackgroundMyocardial perfusion imaging (MPI) is a well-established diagnostic tool to evaluate coronary artery disease (CAD) and also an effective prognostic tool for patients with CAD. However, few studies investigated the prognostic value of attenuation correction (AC) in MPI, and the results were controversial.ObjectivesTo investigate the prognostic value of computed tomography (CT)-based AC thallium-201 (Tl-201) MPI.MethodsA total of 108 consecutive patients who underwent Tl-201 MPI and received coronary angiography within 90 days were included. Medical records were reviewed and missing information was completed after telephone contact. The prognostic value was evaluated by Kaplan-Meier analysis, univariable and multivariable Cox proportional hazards model.ResultsAfter a mean follow-up of 7.72 ± 3.72 years, 27 patients had died, 41 had been readmitted for cardiovascular (CV)-related events and 44 had reached the composite of death plus CV-related re-admission. Kaplan-Meier curves for all-cause mortality for SSS with a cutoff value of 13 for AC and 16 for non-AC (NAC) images showed a significant difference between the two curves for both AC and NAC images (p = 0.011 for AC and p = 0.021 for NAC). In the multivariable model, SSS and SRS showed similar independent predictive values in predicting all-cause mortality and composite of all-cause mortality plus CV-related re-admission, in both AC and NAC images. Subgroup analysis implicated that AC MPI possibly provided better risk stratification in obese patients.ConclusionCT-based AC and NAC MPI showed similar value and were the only significant predictors for the composite of mortality and CV events.

Relationship between Semi-Quantitative Parameters of Thallium-201 Myocardial Perfusion Imaging and Coronary Artery Disease.

This study aimed to investigate the diagnostic performance of semi-quantitative parameters of thallium-201 myocardial perfusion imaging (MPI) for coronary artery disease (CAD). From January to December 2017, patients were enrolled who had undergone Tl-201 MPI and received cardiac catheterization for coronary artery disease within three months of MPI. Receiver operating characteristics (ROC) analysis was used to determine the optimal cutoff values of semi-quantitative parameters. A comparison of the sensitivity and specificity of these parameters based on different subgroupings was further performed. A total of 130 patients were enrolled for further analysis. Among the collected parameters, the stress total perfusion deficit (sTPD) had the highest value of the area under curve (0.813) under the optimal cutoff value of 3.5%, with a sensitivity and specificity of 73.5% and 74.5%, respectively (p = 0.0000), for the diagnosis of CAD. With further subgrouping analysis based on history of diabetes or dyslipidemia, the sensitivity and specificity showed similar results. Based on the currently collected data and image acquisition conditions, the sTPD parameter has a clinical role for the diagnosis of CAD with a cutoff value of 3.5%.

The clinical usefulness of phase analysis in detecting coronary artery disease using dipyridamole thallium-201-gated myocardial perfusion imaging with a cadmium-zinc-telluride camera

BackgroundPrevious studies have demonstrated left ventricular mechanical dyssynchrony (LVMD) in patients with severe coronary artery disease (CAD) with ≥ 70% stenosis. The aim of this study was to evaluate the clinical usefulness of stress/rest LVMD in the diagnosis of CAD with ≥ 50% stenosis using dipyridamole thallium-201 (Tl-201) myocardial perfusion imaging (MPI) with a cadmium-zinc-telluride camera. Methods and ResultsA total of 476 patients without known CAD who underwent dipyridamole Tl-201 MPI and coronary angiography within 6 months were retrospectively reviewed. LVMD parameters including phase standard deviation and phase histogram bandwidth, phase skewness and phase kurtosis, as well as myocardial perfusion and myocardial stunning were assessed in post-stress and rest MPI. Relationships between the presence of CAD on coronary angiography and single photon emission computerized tomography (SPECT) parameters were evaluated. The presence of perfusion abnormalities was the best diagnostic tool in detecting CAD. Although less left ventricular synchrony was observed post-stress in the CAD group compared to the non-CAD group, no significant dyssynchrony was noted. ConclusionsThe addition of phase analysis to help diagnose CAD in Tl-201-gated SPECT with dipyridamole stress may have limited value in patients with CAD with ≥ 50% stenosis.

Creation and characterization of normal myocardial perfusion imaging databases using the IQ·SPECT system

BackgroundImage acquisition by short-time single-photon emission-computed tomography (SPECT) has been made feasible by IQ·SPECT. The aim of this study was to generate normal databases (NDBs) of thallium-201 (201Tl) myocardial perfusion imaging for IQ·SPECT, and characterize myocardial perfusion distribution. Methods and resultsWe retrospectively enrolled 159 patients with a low likelihood of cardiac diseases from four hospitals in Japan. All patients underwent short-time 201Tl myocardial perfusion IQ·SPECT with or without attenuation and scatter correction (ACSC) in either supine or prone position. The mean myocardial counts were calculated using 17-segment polar maps. Three NDBs were derived from supine and prone images as well as supine images with ACSC. Differences between the supine and prone positions were observed in the uncorrected sex-segregated NDBs in the mid-inferolateral counts (p ≤ 0.016 for males and p ≤ 0.002 for females). Differences between IQ·SPECT and conventional SPECT were also observed in the mid-anterior, inferolateral, and apical lateral counts (p ≤ 0.009 for males and p ≤ 0.003 for females). Apical low counts attributed to myocardial thinning were observed in the apical anterior and apex segments in the supine IQ·SPECT NDB with ACSC. ConclusionsThere were significant differences between uncorrected supine and prone NDBs, between uncorrected supine NDB and supine NDB with ACSC, and between uncorrected supine NDB and conventional SPECT NDB. Understanding the pattern of normal distribution in IQ-SPECT short-time acquisitions with and without ACSC will be helpful for interpretation of imaging findings in patients with coronary artery disease (CAD) or low likelihood of CAD and the NDBs will aid in quantitative analysis.

IQ-SPECT for thallium-201 myocardial perfusion imaging: effect of normal databases on quantification

Although IQ-single-photon emission computed tomography (SPECT) provides rapid acquisition and attenuation-corrected images, the unique technology may create characteristic distribution different from the conventional imaging. This study aimed to compare the diagnostic performance of IQ-SPECT using Japanese normal databases (NDBs) with that of the conventional SPECT for thallium-201 (201Tl) myocardial perfusion imaging (MPI). A total of 36 patients underwent 1-day 201Tl adenosine stress-rest MPI. Images were acquired with IQ-SPECT at approximately one-quarter of the standard time of conventional SPECT. Projection data acquired with the IQ-SPECT system were reconstructed via an ordered subset conjugate gradient minimizer method with or without scatter and attenuation correction (SCAC). Projection data obtained using the conventional SPECT were reconstructed via a filtered back projection method without SCAC. The summed stress score (SSS) was calculated using NDBs created by the Japanese Society of Nuclear Medicine working group, and scores were compared between IQ-SPECT and conventional SPECT using the acquisition condition-matched NDBs. The diagnostic performance of the methods for the detection of coronary artery disease was also compared. SSSs were 6.6±8.2 for the conventional SPECT, 6.6±9.4 for IQ-SPECT without SCAC, and 6.5±9.7 for IQ-SPECT with SCAC (p=n.s. for each comparison). The SSS showed a strong positive correlation between conventional SPECT and IQ-SPECT (r=0.921 and p<0.0001), and the correlation between IQ-SPECT with and without SCAC was also good (r=0.907 and p<0.0001). Regarding diagnostic performance, the sensitivity, specificity, and accuracy were 80.8, 78.9, and 79.4%, respectively, for the conventional SPECT; 80.8, 80.3, and 82.0%, respectively, for IQ-SPECT without SCAC; and 88.5, 86.8, and 87.3%, respectively, for IQ-SPECT with SCAC, respectively. The area under the curve obtained via receiver operating characteristic analysis were 0.77, 0.80, and 0.86 for conventional SPECT, IQ-SPECT without SCAC, and IQ-SPECT with SCAC, respectively (p=n.s. for each comparison). When appropriate NDBs were used, the diagnostic performance of 201Tl IQ-SPECT was comparable with that of the conventional system regardless of different characteristics of myocardial accumulation in the conventional system.

A Comparison of Heart Rate Response between 12 hours Caffeine Abstinence and 24 hours in Adenosine Stress Myocardial Perfusion Imaging.

The aim of this study was to examine whether the heart rate response to adenosine differs after 12 hours [Good control (Good-C)] versus 24 hours [Excellent control (Exc-C)] of caffeine abstinence in adenosine stress thallium-201 (TL) myocardial perfusion imaging (MPI). Patients (n=729) with suspected ischemic heart disease underwent adenosine TL-MPI after 12 (n=226) and 24 (n=503) hours of caffeine abstinence. There was not significant differences between the heart rate of Exc-C and Good-C in 0-2 min after adenosine infusion (0 min 63.7±9.5 versus 63.7±10.0, 1 min 66.4±10.6 versus 65.3±10.5, 2 min 72.3±11.2 versus 70.6±11.4). The heart rate of Exc-C was higher compared to Good-C in 3-6 min after adenosine infusion (3 min 75.6 ±11.7 versus 73.3±11.6 p=0.013, 4 min 79.2±12.9 versus 76.7±12.2 p=0.012, 5 min 79.4±12.6 versus 76.8±12.4 p=0.009, 6 min 79.4±12.5 versus 77.0±12.3 p=0.016). Therefore, the longer caffeine abstinence, namely 24 hours self-restraint, is effective in adenosine TL-MPI.

Chest Pain with Normal Thallium-201 Myocardial Perfusion Image - Is It Really Normal?

Thallium-201 myocardial perfusion image (MPI) is commonly used to detect coronary artery disease in patients with chest pain. Although a normal thallium-201 MPI result is generally considered to be a good prognosis and further coronary angiogram is not recommended, there are still a few patients who suffer from unexpected acute coronary events. The aim of this study was to investigate the clinical prognosis in patients with normal thallium-201 MPI. From January 2006 to August 2012, a total 22,003 patients undergoing thallium-201 MPI in one tertiary center were screened. Of these, 8092 patients had normal results and were investigated retrospectively. During follow-up, 54 patients underwent coronary angiogram because of refractory typical angina pectoris or unexpected acute coronary events. These 54 patients were divided into 2 groups: group I consisted of 26 (48.1%) patients with angiography-proven significant coronary artery stenosis, and group II consisted of 28 (51.9%) patients without significant stenosis. Patients in group I had a higher prevalence of prior coronary stenting and electrocardiographic features of ST depression compared with patients in group II. The multivariate analysis demonstrated that both prior coronary stenting and ST depression were risk predictors of unexpected acute coronary events in the patients with normal thallium-201 MPI [odds ratio (OR), 5.93; 95% confidence interval (CI): 1.03-34.06, p = 0.05 and OR, 7.10; 95% CI: 1.28-39.51, p = 0.03,respectively]. Although there is a low incidence of unexpected acute coronary events in patients with chest pain and normal thallium-201 MPI, physicians should be aware of the potentials risk in certain patients in this specific population.

Role of multimodality imaging including Thallium-201 myocardial perfusion imaging in the diagnosis and monitoring of treatment response in cardiac sarcoidosis

Role of multimodality imaging including Thallium-201 myocardial perfusion imaging in the diagnosis and monitoring of treatment response in cardiac sarcoidosis

The immediate and one-year outcomes of dialysis patients with refractory angina treated by enhanced external counterpulsation

Adult dialysis patients with angina pectoris refractory to medical treatment or revascularization are not uncommon. Enhanced external counterpulsation (EECP) has been proven to be effective in reducing myocardial ischemia and refractory angina. The objective of this study was to assess the immediate and 1-year effects of EECP treatment in dialysis patients with refractory angina. Thirty-six consecutive dialysis patients were treated with EECP, and a follow-up was conducted after 1 year. The Canadian Cardiovascular Society (CCS) Angina Grading Scale was used to measure angina severity. Medications were recorded before EECP treatment, at the end of treatment, and at 1-year follow-up. Adverse events and risk factors of cardiovascular disease were recorded and analyzed. At 1-year follow-up, data from patients improving by at least one CCS class after treatment were compared with data from patients showing no improvement. The improvement rates in CCS class were 85% immediately after EECP and 66% at 1-year follow-up. Thallium-201 myocardial perfusion imaging demonstrated a reversible resolution of 40% and improvement of 25% immediately after EECP treatment. Diabetes mellitus and high serum phosphate levels were risk factors affecting whether the beneficial effects of EECP treatment could be sustained (p < 0.05). Major adverse events were rare. EECP shows potential for refractory angina in dialysis patients. The beneficial effects were sustained for more than 1 year in 66% patients. Diabetes mellitus and high serum phosphate levels were major factors impacting the sustained effectiveness of EECP treatment. Nonetheless, adequately powered future studies are necessary to assess safety and efficacy of this procedure.

Myocarditis with fulminant type 1 diabetes mellitus diagnosed by cardiovascular magnetic resonance imaging: a case report

BackgroundFulminant type 1 diabetes is a non-autoimmune disorder characterized by sudden onset. This complication is rarely associated with myocarditis, suggesting an involvement of viral infection. We report a patient with myocarditis who was admitted for fulminant type 1 diabetes and diagnosed using a combination of non-invasive techniques.Case presentationWe describe the case of a 25-year-old Japanese man with fulminant type 1 diabetes complicated by myocarditis. The patient was admitted with flu-like symptoms and diabetic ketoacidosis, followed by chest pain the next day. Myocardial damage was suspected based on ST-segment elevation on electrocardiogram and elevation of cardiac enzymes. However, coronary angiography revealed no abnormality in the coronary arteries. We diagnosed myocarditis by a combination of echocardiography, cardiovascular magnetic resonance imaging (CMR), as well as Thallium-201 and Iodine-123 beta-methyl iodophenyl pentadecanoic acid (Tl-201 BMIPP and I-123 BMIPP) and myocardial imaging. More importantly, CMR revealed diffuse enhancement in the subepicardium of the left ventricle with late gadolinium enhancement, consistent with myocardial edema. The patient was successfully treated, received a two-week education program on diabetes and discharged without complication.ConclusionsThe rapid onset and flu-like symptoms strongly suggest the involvement of viral infection in the pathogenesis of fulminant type 1 diabetes and myocarditis. While cardiac muscle biopsy is routinely performed, this case demonstrates that a combination of non-invasive techniques, especially CMR, may successfully diagnose myocarditis in patients with fulminant type 1 diabetes.

症例 Thallium-201心筋シンチグラムが診断に有用であった肺塞栓症の2例

症例 Thallium-201心筋シンチグラムが診断に有用であった肺塞栓症の2例

Adenosine stress thallium-201 myocardial perfusion imaging for detecting coronary artery disease at an early stage

The aims of this study were to evaluate the diagnostic value of adenosine thallium-201 myocardial perfusion imaging and to compare it with exercise stress thallium-201 myocardial perfusion imaging for detecting coronary artery disease (CAD) at an early stage. Forty-one patients suspected with CAD were randomly divided into two groups. In Group 1 (n=21) adenosine stress was undertaken; the exercise stress myocardial perfusion imaging was performed in Group 2 (n=20). Coronary angiography (CAG) was performed in each patient within 2 weeks before or after single photon emission computed tomography (SPECT). Adenosine stress group vs. exercise stress group, the sensitivity was 92.86% vs. 100.0%, specificity 57.14% vs. 60.0%, positive predictive value 81.25% vs. 71.43%, negative predictive value 80.0% vs. 100.0%, accuracy 80.95% vs. 80.0% respectively. Detection rates of vessels of coronary artery lesions were 66.67% in Group 1 and 72.22% in Group 2 (P> 0.05). The side effects were mild and transient. Our results demonstrated that adenosine stress myocardial perfusion imaging is a safe and reliable diagnostic method for an early stage of CAD. As a comparative sensitivity and accuracy with exercise stress thallium-201 myocardial perfusion imaging, adenosine stress testing may provide a feasible alternative pharmacological stress method in myocardial SPECT for detection of CAD.

Biodistribution of bone marrow mononuclear cells in chronic chagasic cardiomyopathy after intracoronary injection

Background Animal and human clinical studies have indicated that bone marrow (BM) mononuclear cell (MNC) therapy for Chagasic Cardiomyopathy (ChC) is feasible, safe and potentially efficacious. Nevertheless, little is known about the retention of these cells after intracoronary (IC) infusion. Methods Our study investigated the homing of technetium-99m ( 99mTc) labeled BM MNCs and compared it to thallium-201 ( 201Tl) myocardial perfusion images using the standard 17-segment model. Six patients with congestive heart failure of chagasic etiology were included. Results Scintigraphic images revealed an uptake of 5.4% ± 1.7, 4.3% ± 1.5 and 2.3% ± 0.6 of the total infused radioactivity in the heart after 1, 3 and 24 h, respectively. The remaining activity was distributed mainly to the liver and spleen. Of 102 segments analyzed, homing took place in 36%. Segments with perfusion had greater homing (58.6%) than those with decreased or no perfusion (6.8%), p < 0.0001. There was no correlation between the number of injected cells and the number of segments with homing for each patient ( r = − 0.172, p = 0.774). Conclusions These results indicate that 99mTc-BM MNCs delivered by IC injection homed to the chagasic myocardium. However, cell biodistribution was heterogeneous and limited, being strongly associated with the myocardial perfusion pattern at rest. These initial data suggest that the IC route may present limitations in chagasic patients and that alternative routes of cell administration may be necessary.

Clinical Value of Normal Thallium-201 Myocardial Perfusion Imaging in Elderly Patients

Clinical Value of Normal Thallium-201 Myocardial Perfusion Imaging in Elderly Patients

Assessment of myocardial viability in patients with myocardial infarction using twenty-four hour thallium-201 late redistribution imaging

Rest thallium-201 (201Tl) myocardial perfusion imaging has been widely used for evaluation of myocardial ischemia/viability after myocardial infarction, but the ideal timing for imaging after injection to maximally estimate viability is not well established. Thirty-six patients with myocardial infarction underwent the initial, 3 h, and 24 h redistribution imaging after intravenous injection of 148-185 MBq 201Tl. The initial and 3 h images, the initial and 24 h images, and the 3 and 24 h images were compared double-blinded. Out of the 184 abnormal segments based on the initial imaging, 56 (30%) segments improved by at least 1 grade on the 3 h imaging while 78 (42%) segments improved by at least 1 grade on the 24 h imaging. The 24 h late imaging detected more viable myocardium than the 3 h imaging did, with a significant difference (chi2= 5.680, p = 0.017). There were 158 abnormal segments on the 3 h imaging, with average 28% (44) segments improved by at least 1 grade on the 24 h imaging. There were 128 initial abnormal segments with no improvement on the 3 h imaging. Out of these segments, the 24 h late redistribution imaging detected additional redistribution in 26 segments, taking up 20%. Twenty-four hour late 201Tl imaging will demonstrated additional redistribution in patients who have incompletely reversible defects on early redistribution imaging at 3h.

Twenty-four-hour thallium-201 late redistribution imaging enhances the detection of myocardial viability after myocardial infarction

Background Thallium-201 ( 201Tl) myocardial perfusion imaging has been widely used for evaluation of myocardial ischemia/viability after myocardial infarction. The 3- to 4-h early redistribution imaging has underestimated a considerable part of viable myocardium, while the 24-h late redistribution imaging may enhance the detection of myocardial ischemia/viability, but remains controversial. Methods Thirty-eighty patients with myocardial infarction underwent the initial, 3-h, and 24-h redistribution imaging after intravenous injection of 148–185 MBq 201Tl. Image quality analysis was performed using a four-grade model: excellent, good, moderate, and poor. The initial and 3-h images, the initial and 24-h images, and the 3- and 24-h images were compared double-blinded. Results The 3- and 24-h images showed no significant differences in image quality according to the four-grade model ( P=.3580). Out of the 194 abnormal segments based on the initial imaging, 60 (31%) segments improved by at least one grade on the 3-h imaging, while 86 (44%) segments improved by at least one grade on the 24-h imaging. The 24-h late imaging detected more viable myocardium than the 3-h imaging did, with a significant difference ( χ 2=7.4235, P=.0064). There were 164 abnormal segments on the 3-h imaging, with an average 30% (48) segments improved by at least one grade on the 24-h imaging. There were 134 initial abnormal segments without any improvement on the 3-h imaging. Out of these segments, the 24-h late redistribution imaging detected additional redistribution in 30 segments, taking up 22%. The mean global score on the 3-h imaging significantly decreased compared to that on the initial imaging ( t=5.71, P<.0001), and the mean global score on the 24-h imaging further decreased significantly compared to that on the 3-h imaging ( t=6.28, P<.0001). Conclusions Twenty-four-hour late 201Tl imaging, with satisfactory image quality, enhances the detection of myocardial viability after myocardial infarction.

Clinical and Echocardiographic Aspects of Mid‐Ventricular Hypertrophic Cardiomyopathy

Three cases of patients with hypertropic cardiomyopathy, apical aneurysm, and mid-ventricular obstruction are presented. Two patients were diagnosed first by two-dimensional and Doppler echocardiography, which showed mid-ventricular obliteration, characteristic hourglass image, and paradoxic jet flow. One patient with suboptimal echocardiogram was necessary to perform contrast echocardiogram. Clinical picture was characterized by angina and dyspnea. Thallium myocardial imaging revealed perfusion abnormalities in apical region, ischemia or necrosis. Cardiac catheterism showed mid-ventricular obliteration and significant intraventricular gradient and coronary arteries angiography without lesions.

Usefulness of Thallium-201 myocardial perfusion SPECT images in type 2 diabetic patients without typical chest pain

Usefulness of Thallium-201 myocardial perfusion SPECT images in type 2 diabetic patients without typical chest pain

Does intraoperative evaluation of left ventricular contractile reserve predict myocardial viability? A clinical study using dobutamine stress echocardiography in patients undergoing coronary artery bypass graft surgery.

To determine the contractile reserve of the left ventricle during reperfusion as a predictor of myocardial viability in patients undergoing coronary artery bypass graft surgery, we measured the response of left ventricular regional wall motion and thickening by using dobutamine stress echocardiography (DSE) after myocardial revascularization. All patients were monitored with radial and pulmonary arterial catheters, transesophageal echocardiography, standard five-lead clinical electrocardiography, and three-channel Holter electrocardiography. Immediately after separation from cardiopulmonary bypass, dobutamine was administered IV starting at 5 microg. kg(-1). min(-1), with increases in rate every 3 min to 10, 20, 30, and 40 microg. kg(-1). min(-1). Within 1 wk after surgery, resting and redistribution thallium-201 myocardial perfusion imaging (thallium studies) was performed to assess the relationship between the intraoperative contractile response and myocardial viability. One-hundred patients completed DSE up to 10 microg. kg(-1). min(-1), and 85 patients received the larger escalating doses of the DSE. Seventy-two patients had postoperative thallium studies. At the completion of the small-dose dobutamine infusion, 689 (97.7%) of 705 segments had a normal response (improvement), and 16 segments (2.3%) had a positive response (deterioration). During large-dose dobutamine infusion, 577 (95.8%) of 602 segments had a normal response, and 25 segments (4.2%) had a positive response. Myocardial segments that had a positive response during large-dose DSE (48%) were more likely to be considered as nonviable on postoperative thallium studies compared with segments that had a normal response (14.7%) (P < 0.00001). By using thallium studies as the reference standard, the sensitivity of DSE was low (31% and 48% for small- and large-dose DSE, respectively) in predicting nonviable myocardium. However, the specificity was higher (86% and 85% for small- and large-dose DSE, respectively). In a separate analysis of patients who developed new regional wall motion abnormalities (RWMA) in the early intraoperative reperfusion period, 15 (75%) of 20 abnormally contracting myocardial segments had normal postoperative thallium studies. Our results demonstrate that a normal response to DSE is highly specific for viable myocardium; however, a positive response to DSE has low sensitivity in predicting nonviable myocardium. The majority of new postbypass regional wall motion abnormalities appear to be related to stunned myocardium.

Improved accuracy of SPECT thallium-201 using wavelet prefiltering

Background: Image noise significantly degrades the quality of nuclear cardiac images. Noise reduction using conventional Fourier techniques has become an essential part of reconstruction. Wavelet filtering has several theoretical advantages over Fourier based methods but has not been evaluated in clinical nuclear cardiology. Methods: We identified 695 patients referred for exercise stress testing using SPECT Tl-201 who either had less than a 5% probability of coronary disease or catheterization documented disease within 60 days of stress testing. Patients with documented MI, pathologic Q waves, LBBB, non-ischemic cardiomyopathy or prior bypass grafting were not included. There were 315 women and 380 men, 309 had coronary disease and 386 were low probability. Twenty men and 20 women were taken from the low probability group to create gender and filter specific normal databases. Quantitative SPECT analysis was performed by conventional Fourier techniques using a Butterworth filter with a cutoff of 0.4 of the Nyquist and an order of 8. Wavelet prefiltering was performed by transforming the each frame of the projection data with a 4 th order Coiflet filter then performing a soft threshold using 4.5x the standard deviation of the noise for each frame. Quantitative analysis was performed using volume weighted radial plots on the remaining 655 patients and normals using both prefilters. Corresponding accuracy for each technique was determined by calculating the area under the receiver operating curve. Results: There was a small but statistically significant increase in accuracy using the Coiflet prefilter. The area under the ROC curve was 0.81±0.02 using the conventional Butterworth prefilter versus 0.84±0.02 using the Coiflet prefilter (p = 0.02). Conclusions: Wavelet prefiltering results in a small but statistically significant increase in accuracy of quantitative SPECT thallium-201 myocardial perfusion imaging.