Left bundle branch block and coronary artery disease: Accuracy of dipyridamole thallium-201 single-photon emission computed tomography in patients with exercise anteroseptal perfusion defects

Background  Reduced septal or anteroseptal uptake of thallium-201 during exercise is frequently observed in patients with left bundle branch block (LBBB) even in the absence of left anterior descending (LAD) coronary artery disease. The purpose of this study was to evaluate prospectively the accuracy of dipyridamole²⁰¹TI single-photon emission computed tomography (SPECT) in detecting LAD coronary artery disease in patients with LBBB and septal or anteroseptal perfusion defects on exercise²⁰¹TI SPECT. Methods and Results  Twelve consecutive patients (10 men and two women) with complete LBBB and septal or anteroseptal perfusion defects on exercise²⁰¹TI SPECT underwent dipyridamole²⁰¹TI SPECT. The delay between dipyridamole and exercise was 2 to 30 days. Coronary angiography was performed during this period in all patients. Six (50%) of 12 patients with exercise perfusion defects showed normal perfusion after dipyridamole; all had normal coronary angiograms. The remaining six patients also had positive results of dipyridamole studies, two with moderate and four with severe septal or anteroseptal perfusion defects. Coronary angiography showed significant (>50%) LAD coronary artery stenosis in three patients; three patients with severe septal or anteroseptal perfusion defects after dipyridamole had normal coronary angiograms. Neither the evaluation of apical involvement nor the presence of dilated ventricles, decreased left ventricular ejection fraction, or wall motion abnormalities could help to identify (or explain) false-positive results. Conclusion  This study confirms that dipyridamole is more accurate than exercise in excluding LAD coronary artery disease. However, there are still false-positive results and the severity of the septal or anteroseptal perfusion defect does not add additional information to identify LAD coronary artery disease. Coronary angiography is thus necessary for positive dipyridamole study results to identify coronary artery disease as a major prognostic factor in patients with LBBB.     

Myocardial perfusion in patients with left bundle branch block and without coronary artery disease]

For the evaluation of myocardial perfusion in patients with left bundle branch block (LBBB), we performed exercise stress (Ex)-redistribution (RD) myocardial tomography with thallium-201 (201Tl) in 23 patients with LBBB and without coronary artery disease (CAD). Myocardial images in patients with LBBB were compared with those of 9 patients with CAD who showed Ex induced transient septal defect. Bull'-eye maps (201Tl distribution maps at Ex and RD and 201Tl washout rate [WOR] map) were made from myocardial tomograms. In 23 patients with LBBB, 15 patients (65%) developed myocardial perfusion abnormality. In 10 (67%) of these 15 patients, transient perfusion defect appeared in the entire septum (diffuse type). On the other hand in 5 patients (33%), localized fixed perfusion defect developed at the boundary between septum and anterior wall (focal type). In focal type, every patient had other disease such as hypertension, aortic stenosis or sick sinus syndrome. While in patients with diffuse type, other diseases were observed in 30% (p less than 0.05) and they were limited to hypertension or diabetes mellitus. These facts suggested that mechanisms of perfusion abnormalities might be different between these two groups. We compared the perfusion abnormality between LBBB diffuse type and CAD. The extent of the defects was not different between two groups. Although apex was included within the defect in 89% of CAD population, apical defect was observed in only 20% of diffuse type (p less than 0.05). Minimal 201Tl WOR and 201Tl uptake ratio of septum to lateral wall indicated that exercise induced septal defect was slighter in diffuse type than CAD.(ABSTRACT TRUNCATED AT 250 WORDS)     

Noninvasive stress testing of myocardial perfusion defects: head-to-head comparison of thallium-201 SPECT to MRI perfusion

Background  To evaluate the diagnostic value of magnetic resonance imaging (MRI) of myocardial perfusion in the assessment of flow-limiting epicardial stenosis in a head-to-head comparison with abnormal thallium-201 (²⁰¹TI) single photon emission tomography (SPECT) studies in patients with predominantly known coronary artery disease (CAD). Methods and Results  Twenty-one patients (mean age 65 ± 10 years) with reversible myocardial perfusion defects on ²⁰¹TI-SPECT images during dipyridamole-stimulated hyperemia were recruited for study purpose. Within 5 days of the ²⁰¹TI-SPECT study, myocardial perfusion was studied again with MRI during dipyridamole stimulation and at rest. Overall, ²⁰¹TI-SPECT identified 30 reversible regional perfusion defects. The sensitivity to detect hypoperfused segments was 70% (21/30) with the GRE-MRI perfusion analysis with ²⁰¹TI-SPECT as reference. When patients were subgrouped according to the extent of regional reversible perfusion defects on ²⁰¹TI-SPECT, mild- (SDS: 2-4), moderate- (SDS: 5-8), and severe- (SDS > 8) perfusion defects were also identified by GRE-MRI perfusion analysis in 75% (6/8), in 56% (9/16) and 100% (6/6), respectively. Conclusions  GRE-MRI first-pass stress perfusion imaging may not identify up to 30% of mild-to-moderate perfusion defects in a group of preselected patients with predominantly known CAD and abnormal ²⁰¹TI-SPECT studies.     

QRS score versus ST-segment changes in patients undergoing Tl-201 scintigraphy using dipyridamole infusion

BACKGROUND: ST-segment changes after dipyridamole infusion followed by handgrip isometric stress lack diagnostic value, because of the low sensitivity for the detection of coronary artery disease (CAD). In addition, an abnormal QRS score during exercise had a greater diagnostic ability than ST-segment changes to detect CAD. This study was undertaken to compare QRS score values with ST-segment changes during thallium 201 scintigraphy via dipyridamole infusion. METHODS AND RESULTS: In this study 128 patients (101 men and 27 women), aged 53 to 72 years (mean, 59 +/- 8 years), underwent Tl-201 scintigraphy after dipyridamole infusion and handgrip isometric stress, as well as coronary angiography. QRS score values and ST-segment changes after dipyridamole infusion and handgrip isometric stress were also estimated. CAD was detected in 96 patients (75%), whereas normal coronary arteries were found in 32 (25%). According to scintigraphic data, 48 patients (37%) had no reversible perfusion defects whereas 80 (63%) had at least 1 reversible perfusion defect. Sensitivities for an abnormal QRS score and ST-segment deviation were 68% versus 18% ( P < .01) for detection of CAD and 75% versus 19% for detection of myocardial ischemia ( P < .01), respectively. Similar specificities were found ( P = not significant). CONCLUSIONS: An abnormal QRS score significantly improves the low sensitivity of ST-segment changes for the detection of myocardial ischemia and CAD by use of Tl-201 scintigraphy with dipyridamole infusion and handgrip isometric stress.     

Effect of aminophylline on thallium-201 washout rate during myocardial perfusion imaging with dipyridamole

Thallium-201 myocardial perfusion imaging with dipyridamole was performed on 78 patients (pts) with suspected coronary artery disease (CAD). Twenty eight pts had normal coronary arteries (control group), and 50 pts had 50% or greater stenosis in one or more major coronary arteries (CAD group). In control group, aminophylline (Am) was infused intravenously on 12 pts during dipyridamole testing. Mean washout rate (WR) of these 12 pts was greater than that of 16 pts without Am (42% vs 35%, p less than 0.01). Then normal limit of WR was defined separately from the pts of control group with and without Am. The sensitivity for detecting the pts with CAD by WR analysis which normal limit was calculated separately with and without Am was 92% (46/50). When normal limit of WR was determined from all pts in control group, the sensitivity decreased to 84% (42/50). Am significantly affected thallium-201 washout during dipyridamole testing. WR of CAD pts should be estimated by specific set of normal limit with and without Am.     

Myocardial scintigraphy with thallium-201 and technetium-99m-hexakis-methoxyisobutylisonitrile in left bundle branch block: a study in patients with and without coronary artery disease

In left bundle branch block (LBBB) thallium-201 myocardial scintigraphy frequently reveals septal abnormalities in the absence of coronary artery disease (CAD) and gives rise to false-positive results in patients with suspected CAD. It has not yet been clarified which pathophysiological mechanism is responsible for these perfusion abnormalities. A total of 66 patients with constant LBBB were investigated with ²⁰¹T1 or technetium-99m-hexakis-methoxyisobutylisonitrile (MIBI), 62 underwent coronary angiography. Of 12 patients without left anterior descending artery (LAD) or right coronary artery (RCA) stenoses, 11 had a reversible septal activity deficit after ²⁰¹T1 stress injection, whereas 20 of 22 patients without relevant CAD showed a constant stress/rest septal deficit using MIBI. Regarding patients with significant LAD and/or RCA stenoses, both radiopharmaceuticals almost always showed a reversible septal deficit: with ²⁰¹T1 in 15 of 16 individuals and with MIBI in 14 of 15. In 12 patients ²⁰¹T1 was reinjected at rest. In those who had LAD or RCA stenoses (n = 5), early septal activity uptake after stress injection was poorer than that after rest injection; in the absence of CAD (n = 7), septal stress uptake corresponded with that of rest injection. It is concluded that septal perfusion abnormalities in LBBB and the absence of CAD are characterized by an exercise-independent reduction of septal blood flow per mass of viable myocardium and that stress/rest injection protocols of myocardial perfusion tracers are able to differentiate between LBBB with and without CAD.Dedicated to Prof. Dr. Dr. h.c. H. Hundeshagen on the occasion of his 65th birthday Correspondence to: W.H. Knapp     

Thallium-201 myocardial SPECT in left bundle branch block: Diagnosis of myocardial ischemia with a disease-specific reference database

Background  The aim of this study was to assess the value of a myocardial perfusion single photon emission computed tomography (SPECT) reference file for patients with left bundle branch block (LBBB). Methods and Results  Tl-201 stress-redistribution myocardial perfusion SPECT studies of patients with complete, permanent LBBB were reviewed retrospectively. To develop a reference database, 18 patients with a low likelihood of coronary artery disease (CAD) were selected. Left ventricular regional average and standard deviation (SD) values of the reference file images were calculated. The diagnostic performance was tested on perfusion images of 49 patients with LBBB, undergoing both scintigraphic and coronary angiographic evaluation, and was compared with a commercial quantitative analysis system using a general reference database. The LBBB reference file performed significantly better in detecting epicardial CAD than did the general reference database (receiver operating characteristic area under the curve 0.835 ± 0.06 vs 0.580 ± 0.08, p < .01). Disease localization also was improved significantly in the territory of the left anterior descending and of the right coronary arteries. Conclusions  The use of a reference file of patients with LBBB and a low likelihood of CAD aids the detection and the localization of myocardial ischemia on Tl-201 myocardial SPECT images of this patient group. The authors thank Professor Mátyás Keltai MD and István Szilvási MD for valuable discussions. The authors also thank József Turák (Mediso Ltd., Budapest, Hungary) for providing technical information on the Interview image processing system.     

Myocardial uptake and clearance of T1-201 in healthy subjects: comparison of adenosine-induced hyperemia and exercise stress

Pharmacologic stress testing with dipyridamole is useful in patients undergoing thallium-201 myocardial perfusion scintigraphy who cannot adequately exercise. Because dipyridamole increases coronary blood flow by reducing the metabolism of adenosine, the authors compared the uptake and clearance of T1-201 following exercise stress testing (EST) and resting intravenous infusion of adenosine (AI) in crossover fashion in 20 healthy men. No perfusion defects or areas of redistribution were noted in any of the scans. Mean absolute myocardial T1-201 uptake was 1.3 times greater with AI than with EST. Mean absolute extracardiac uptake was 2.0 times greater with AI. Mean T1-201 myocardial clearance was virtually the same in all AI and EST views. During AI, 70% of the subjects experienced subjective side effects, mean arterial blood pressure decreased by 15%, and heart rate increased by 48%. The effects of adenosine on T1-201 kinetics in the myocardium are similar to those of EST. Adenosine may be useful as a pharmacologic stress agent in patients undergoing T1-201 myocardial perfusion scintigraphy.     

Evaluation of myocardial perfusion abnormalities with gadolinium-enhanced snapshot MR imaging in humans. Work in progress.

To determine whether myocardial perfusion abnormalities could be detected in patients with coronary artery disease by means of contrast material-enhanced magnetic resonance (MR) images, a snapshot imaging technique was used in six patients with coronary artery disease and four healthy subjects in conjunction with pharmacologic stress (dipyridamole infusion) and bolus injection of gadopentetate dimeglumine. MR images from all patients and healthy subjects were quantitatively analyzed to define spatial changes in signal intensity after administration of dipyridamole and gadopentetate dimeglumine. The resultant findings were compared with findings on thallium-201 scintigrams obtained after administration of dipyridamole and on coronary arteriograms in all patients. Nine myocardial regions supplied by stenosed arteries showed diminished levels of signal intensity after infusion of the contrast agent compared with those of normally perfused regions. These findings were in agreement with those obtained with T1-201 scintigraphy (in eight of nine regions) and arteriography. Thus, contrast-enhanced high-speed MR imaging with use of dipyridamole enabled detection of regional perfusion abnormalities in humans.     

The prognostic value of a normal Tc-99m sestamibi SPECT study in suspected coronary artery disease

BACKGROUND: Myocardial perfusion is widely used for risk stratification of patients with suspected or known coronary artery disease (CAD). Recent years have seen an increasing demand for screening of such patients. The value of a normal stress thallium-201 scanning is well established. The advent of technetium 99m-sestamibi single photon emission computed tomography (SPECT) has enhanced the profile of nuclear cardiology even further as a reliable test for screening. However, in spite of previous reports, there is paucity of large-scale data regarding the prognostic value of a normal Tc 99m-sestamibi scanning result. METHODS: The aim of our study was to assess the incidence of cardiac death and non-fatal myocardial infarction in patients with an intermediate probability of coronary artery disease (CAD). A total of 473 patients with normal stress Tc-99m-sestamibi SPECT were monitored for 30+/-16 (6 to 56) months to assess serious cardiac events. There were 272 men and 201 women, with a mean age of 56+/-2 years, of whom 89% had symptoms suggestive of CAD, 65% had an abnormal exercise electrocardiography, 6% had known CAD, and 5% had a high risk of CAD. The average workload was 9.14 metabolic equivalents, peak exercise heart rate was 93%+/-13% of the age predicted target. RESULTS: The annualized mortality rate was 0.2% (95%CI 0.02% to 0.7%) and no infarctions occurred in this group. CONCLUSIONS: A normal stress Tc-99m-sestamibi is highly predictive of a benign outcome, even in patients with intermediate probability of CAD.     

Significance of diffuse slow washout in dipyridamole loading thallium-201 myocardial perfusion scintigraphy

To assess the significance of diffuse slow washout (DSW) in dipyridamole loading thallium-201 myocardial perfusion scintigraphy, 382 patients were studied. DSW were observed in 69 (24%) of 285 patients with perfusion defects, 5 (5%) of 97 patients without perfusion defects. There was significant relation between DSW and perfusion defects (p less than 0.01). Coronary angiography showed multivessel disease in 84% single vessel disease in 12% of patients with DSW and multivessel disease in 28%, single vessel disease in 50% of patients without DSW. During a mean follow up period of 29 months, initial CABG or PTCA were done in 41%, cardiac death occurred in 12%, nonfatal cardiac events occurred in 7% of patients with DSW and perfusion defects. In patients without DSW, initial CABG or PTCA were done in 11%, cardiac death occurred in 7%, nonfatal cardiac events occurred in 5%. Patients without perfusion defects had good prognosis regardless of the presence or absence of DSW. In conclusion, DSW indicates serious cardiac ischemia in patients with perfusion defects. DSW does not indicate cardiac ischemia in patients without perfusion defects.     

Incremental diagnostic value of dipyridamole echocardiography and exercise thallium 201 scintigraphy in the assessment of presence and extent of coronary artery disease

Background  

The incremental diagnostic information of two noninvasive tests for the detection of coronary artery disease (CAD), dipyridamole echocardiography, and exercise²⁰¹Tl myocardial scintigraphy was assessed in a series of 102 patients with ordered logistic regression and receiver-operating characteristic curves.     

Prognostic value of stress myocardial perfusion single photon emission computed tomography imaging in patients with left bundle branch block

Background. Left bundle branch block (LBBB) may occur with or without structural heart disease. In patients with coronary artery disease the presence of LBBB is associated with an increased risk of cardiovascular events.Methods and Results. This study examined the outcome of 293 medically treated patients with LBBB and symptoms who were undergoing stress thallium-201 single photon emission computed tomography imaging. One hundred seventy-three men and 120 women with an age range of 67 ± 9 years and a pretest probability of coronary artery disease of 77% ± 28% were studied. During a mean follow-up of 33 months 58 hard cardiac events (death or nonfatal myocardial infarction) and 112 total events (hard events, coronary angioplasty, coronary bypass surgery, or cardiac transplantation) occurred. Univariate and multivariate Cox survival analysis with clinical, stress, hemodynamic, and single photon emission computed tomography variables identified the perfusion defect size (chi SQUARE = 27, p = 0.0001) and increased lung thallium uptake as the most important independent predictors of hard or total cardiac events. The hard event-free survival rate was 91% in patients with no or small defects (<15% of left ventricular myocardium) and 72% in patients with large defects (p = 0.0001, RR = 3.2, 95% CI 1.7 to 5.9). The total event-free survival rate was 81% in patients with small defects and 48% in patients with large defects (p = 0.0001, RR = 2.7, 95% CI 1.9 to 4.0). The total event rate was 54% in patients with large perfusion defects and increased lung uptake and 17% in patients with no or small abnormality and normal lung thallium uptake (p = 0.0001).Conclusion. Single photon emission computed tomography perfusion imaging is useful in predicting outcome in patients with LBBB and intermediate pretest probability of coronary artery disease. The size of perfusion abnormality and lung thallium uptake stratified patients into high and low risk groups with a threefold difference in hard and total cardiac events.     

Comparison of stress-only vs. stress/rest with technetium-99m methoxyisobutylisonitrile myocardial perfusion imaging

Unlike conventional thallium-201 myocardial imaging, technetium-99m methoxyisobutylisonitrile (MIBI) requires separate stress and rest injections. We prospectively studied 148 consecutive patients referred for myocardial perfusion studies to determine the diagnostic value of rest images once normal exercise or dipyridamole tomographic images had been obtained. In patients referred with no history of previous myocardial infarction in whom the diagnosis of coronary artery disease was suspected, 45 of 109 (41%) patients had normal stress tomographic images. Obtaining rest images did not alter the final interpretation in any of these cases. From this we infer that in patients with normal images after exercise or dipyridamole administration and no past history of myocardial infarction, ^99mTc-MIBI rest images are not required. This provides several advantages including increased speed of diagnosis, decreased patient radiation exposure, improved cost efficiency and decreased demand on tomographic camera time. Offprint requests to: A.Y. Fung     

Plaque volume,composition, and fraction versus ischemia and outcomes in patients with coronary artery disease

BackgroundThe various plaque components have been associated with ischemia and outcomes in patients with coronary artery disease (CAD). The main goal of this analysis was to test the hypothesis that, at patient level, the fraction of non-calcified plaque volume (PV) of total PV is associated with ischemia and outcomes in patients with CAD. This ratio could be a simple and clinically useful parameter, if predicting outcomes.MethodsConsecutive patients with suspected CAD undergoing coronary computed tomography angiography with selective positron emission tomography perfusion imaging were selected. Plaque components were quantitatively analyzed at patient level. The fraction of various plaque components were expressed as percentage of total PV and examined among patients with non-obstructive CAD, suspected stenosis with normal perfusion, and those with reduced myocardial perfusion. Clinical outcomes included all-cause mortality and myocardial infarction.ResultsIn total, 494 patients (age 63 ​± ​9 years, 55% male) were included. Total PV and all plaque components were significantly larger in patients with reduced myocardial perfusion compared to patients with normal perfusion and those with non-obstructive CAD. During follow-up 35 events occurred. Patients with any plaque component ​≥ ​median showed worse outcomes (log-rank p ​< ​0.001 for all). In addition, low-attenuation plaque ​≥ ​median was associated with worse outcomes independent of total PV (adjusted HR: 2.754, 95% CI: 1.022–7.0419, p ​= ​0.045). The fractions of the various plaque components were not associated with outcomes.ConclusionLarger total PV or any plaque component at patient level are associated with abnormal myocardial perfusion and adverse events. The various plaque components as fraction of total PV lack additional prognostic value.     

Intravenous dipyridamole thallium-201 SPECT imaging in patients with left bundle branch block

Tl-201 exercise imaging in patients with left bundle branch block (LBBB) has proven to be indeterminate for significant left anterior descending (LAD) coronary artery stenosis because of the presence of immediate septal perfusion defects with redistribution on delayed images in almost all cases. Tl-201 redistribution occurs regardless of the presence or absence of LAD stenosis. Nineteen patients having LBBB were evaluated with dipyridamole Tl-201 SPECT. Fourteen of these subjects had normal dipyridamole Tl-201 SPECT imaging. Three patients had normal coronary angiograms. None of the remaining 11 patients with normal dipyridamole Tl-201 SPECT images was found to have clinical coronary artery disease in a 5-11 month follow-up period. Five patients had abnormal septal perfusion. Four underwent coronary angiography. One had a significant LAD stenosis. The single patient with septal redistribution who refused to undergo coronary angiography died shortly thereafter of clinical coronary artery disease. This preliminary work suggests that dipyridamole Tl-201 SPECT may be more useful for excluding LAD stenosis in patients with LBBB than Tl-201 exercise imaging.     

Comparison of stress-only vs. stress/rest with technetium-99m methoxyisobutylisonitrile myocardial perfusion imaging.

Unlike conventional thallium-201 myocardial imaging, technetium-99m methoxyisobutylisonitrile (MIBI) requires separate stress and rest injections. We prospectively studied 148 consecutive patients referred for myocardial perfusion studies to determine the diagnostic value of rest images once normal exercise or dipyridamole tomographic images had been obtained. In patients referred with no history of previous myocardial infarction in whom the diagnosis of coronary artery disease was suspected, 45 of 109 (41%) patients had normal stress tomographic images. Obtaining rest images did not alter the final interpretation in any of these cases. From this we infer that in patients with normal images after exercise or dipyridamole administration and no past history of myocardial infarction, 99mTc-MIBI rest images are not required. This provides several advantages including increased speed of diagnosis, decreased patient radiation exposure, improved cost efficiency and decreased demand on tomographic camera time.     

Myocardial perfusion SPECT identifies patients with left bundle branch block patterns at high risk for future coronary events

Background  

The value of myocardial perfusion SPECT (MPS) for patients with left bundle branch block (LBBB) or right ventricular apical (RVA) pacing seems reduced. The prognosis of patients with only abnormal activation related perfusion defects (AARD) due to LBBB or RVA-pacing is similar to those with a normal MPS. We assessed the prognostic value of MPS in patients with LBBB or RVA pacing.     

Dipyridamole and exercise SPET provide different estimates of myocardial ischaemic areas: role of the severity of coronary stenoses and of the increase in heart rate during exercise

In patients unable to perform a maximal exercise test, dipyridamole single-photon emission tomography (SPET) has a higher capacity than exercise SPET to detect coronary artery disease (CAD). However, in patients with myocardial ischaemia who are able to perform a maximal exercise test, it is not known whether these two tests may be equally used to assess the areas of myocardial ischaemia. This study was aimed at comparing the results provided by dipyridamole and exercise SPET in CAD patients with documented exercise myocardial ischaemia. Forty CAD patients who had undergone exercise thallium-201 SPET and who had myocardial ischaemia documented by an unequivocally positive exercise test underwent an additional ²⁰¹Tl SPET study after dipyridamole infusion and low-level (40 W) exercise. The extent of defects was compared between the two tests and predictors of discrepant results were sought among data from exercise testing and coronary angiography. The extent of SPET defects was equivalent between the two tests in only 11 patients (28%), larger defects being observed with exercise in 18 [average difference: 12%±5% of left ventricle (LV)] and with dipyridamole in 11 (average difference: 15%±11% of LV). The best independent predictors of discrepancies between the two tests were: (1) increase in heart rate at exercise SPET, with defects being smaller at exercise than after dipyridamole in none of the patients with an increase >60 bpm (0/14), but in 42% of the others (11/26; P=0.004); and (2) an ischaemic territory related to a <70% coronary stenosis, for which SPET defects were always induced at exercise (10/10) but in only 30% (3/10) with dipyridamole (P=0.0004). Exercise and dipyridamole SPET provide different estimates of myocardial ischaemic areas. Dipyridamole allows the unmasking of perfusion abnormalities in patients who have low increases in heart rate at exercise SPET. However, dipyridamole is also much less efficient at inducing perfusion abnormalities in the ischaemic areas supplied by coronary stenoses of intermediate severity at rest angiography. Received 20 January 2000 and in revised form 18 March 2000     

Value of magnetic resonance imaging in patients with a recent myocardial infarction: Comparison with planar thallium-201 scintigraphy

The diagnostic accuracy of spin-echo Magnetic Resonance (MR) imaging in the detection and localization of a recent myocardial infarction (mean 4 days old) was compared to planar thallium-201 scintigraphy in 20 patients with a documented myocardial infarction. A control group of 10 subjects underwent a similar MR imaging procedure without thallium-201 scintigraphy. T1-weighted MR images (TE 30 msec) showed abnormal thinning of the infarcted left ventricular wall during systole (<50% of the opposite wall) in 11 patients (55%). On T2-weighted multi-echo MR images, (TE 30–60–90–120 msec) abnormally increased signal intensity was found in 17 patients and coincided with the location of the infarction. Thallium-201 scintigraphy detected the infarction in 18 patients. Comparison of T2-MR imaging and thallium-201 scintigraphy showed concordant findings in 82% of the left ventricular segments. In 9% of segements, thallium uptake was reduced with normal T2-MR and in 9% we found a normal thallium uptake with abnormal T2-MR findings. In all subjects of the control group, T1-MR images were normal, and only one subject showed increased signal intensity on T2-MR images. We conclude that the diagnostic accuracy of MR imaging in detecting a myocardial infarction is similar to that of T1-201 scintigraphy.