Dobutamine Magnetic Resonance Imaging Research Articles

Early detection of myocardial stunning using low-dose dobutamine magnetic resonance imaging

Early detection of myocardial stunning using low-dose dobutamine magnetic resonance imaging

Chronic total coronary occlusion in patients with intermediate viability: value of low-dose dobutamine and contrast-enhanced 3-T MRI in predicting functional recovery in patients undergoing percutaneous revascularisation with drug-eluting stent

Myocardial viability was evaluated by magnetic resonance imaging (MRI) in patients with chronic total coronary occlusion (CTO) treated with a drug-eluting stent. Change in left ventricular ejection fraction (LVEF) was analysed. Twenty-three patients with CTO underwent delayed-enhancement (DE) and low-dose dobutamine MRI (LD). Diastolic wall thickness (DWT), dobutamine-induced systolic wall thickening (SWT) and DE transmural extension were quantitatively assessed in vessel-related segments, calculating the contribution of viable tissue to SWT, expressed as viability index (VI)=[SWTx(100 - DE)]/100. Patients with transmural enhancement were excluded from revascularisation. At 6 months follow-up, patients underwent coronary angiography (CA) and MRI. Functional recovery was defined as a 2-mm increase in SWT. Transmural enhancement (mean DE 62.88+/-37.18] was present in three patients. Mean DWT, SWT, VI and DE of recanalised patients were 8.03+/-2.35, 2.64+/-1.56, 1.77+/-1.48 mm and 41.97+/-30.32. Revascularisation was successful in 14/16. Follow-up CA showed patency of treated vessels. Functional recovery was achieved in 13 patients. Functional recovery showed significant correlation with SWT (beta 1,779, p=0.015), and even higher correlation with VI (beta 2.032, p=0.011). LVEF improved significantly [Delta 95% confidence interval (CI) -4.47, p=0.0203). Invasive CTO treatment has beneficial effects on myocardial contractility that can be predicted by VI, and on LVEF.

Prediction of myocardial recovery by dobutamine magnetic resonance imaging and delayed enhancement early after reperfused acute myocardial infarction

The purpose was to study dobutamine magnetic resonance cine imaging (DOB-MRI) and delayed myocardial contrast enhancement (DE) early after reperfused acute myocardial infarction (AMI) for the predicion of segmental myocardial recovery and to find the optimal dose of dobutamine. Fifty patients (56+/-12 years, 42 males) with reperfused AMI underwent DOB-MRI and DE studies 3.5 (1-19) days after reperfusion. In DOB-MRI systolic wall thickening (SWT) was measured in 18 segments at rest and during dobutamine at 5, 10 and 20 microg*kg(-1)*min(-1). Dysfunctional segments were identified and the extent of DE was measured for each segment. Segmental recovery was examined after 8 (5-15) months. Two hundred-forty-eight segments were dysfunctional with presence of DE in 193. DOB-MRI showed the best prediction of recovery at 10 microg*kg(-1)*min(-1) of dobutamine with sensitivity of 67%, specificity of 63% and accuracy of 66% using a cut-off value for SWT of 2.0 mm. DE revealed a sensitivity of 68%, specificity of 65% and accuracy of 67% using a cut-off value of 46%. Combined analysis of DOB-MRI and DE did not improve diagnostic performance. Early prediction of segmental myocardial recovery after AMI is possible with DOB-MRI and DE. No improvement is achieved by dobutamine >10 microg*kg(-1)*min(-1) or a combination of DOB-MRI and DE.

CCS/CAR/CANM/CNCS/CanSCMR joint position statement on advanced noninvasive cardiac imaging using positron emission tomography, magnetic resonance imaging and multidetector computed tomographic angiography in the diagnosis and evaluation of ischemic heart disease – executive summary

Over the past few decades, advanced imaging modalities with excellent diagnostic capabilities have emerged. The aim of the present position statement was to systematically review existing literature to define Canadian recommendations for their clinical use. A systematic literature review to 2005 was conducted for positron emission tomography (PET), multidetector computed tomographic angiography and magnetic resonance imaging (MRI) in ischemic heart disease. Papers that met the criteria were reviewed for accuracy, prognosis data and study quality. Recommendations were presented to primary and secondary panels of experts, and consensus was achieved. Indications for PET include detection of coronary artery disease (CAD) with perfusion imaging, and defining viability using fluorodeoxyglucose to determine left ventricular function recovery and/or prognosis after revascularization (class I). Detection of CAD in patients, vessel segments and grafts using computed tomographic angiography was considered class IIa at the time of the literature review. Dobutamine MRI is class I for CAD detection and, along with late gadolinium enhancement MRI, class I for viability detection to predict left ventricular function recovery. Imaging must be performed at institutions and interpreted by physicians with adequate experience and training. Cardiac imaging using advanced modalities (PET, multidetector computed tomographic angiography and MRI) is useful for CAD detection, viability definition and, in some cases, prognosis. These modalities complement the more widespread single photon emission computed tomography and echocardiography. Given the rapid evolution of technology, initial guidelines for clinical use will require regular updates. Evaluation of their integration in clinical practice should be ongoing; optimal use will require proper training. A joint effort among specialties is recommended to achieve these goals.

Which parameters on magnetic resonance imaging determine Q waves on the electrocardiogram?

Studies have demonstrated that patients with Q-wave infarctions on the electrocardiogram (ECG) frequently have nontransmural scar formation, whereas non-Q-wave infarctions may have transmural scars. The precise pathophysiologic substrate that underlies Q waves remains unclear. Magnetic resonance imaging (MRI) is the preferred technique to evaluate patients who have infarction because information can be obtained on function, contractile reserve (viability), and scar tissue. Consecutive patients (n = 69) who had coronary artery disease and a history of myocardial infarction underwent MRI; the protocol included MRI at rest, small-dose dobutamine MRI, and contrast-enhanced MRI. Parameters included left ventricular ejection fraction, left ventricular volumes, end-diastolic wall thickness and contractile reserve in the infarct region, transmurality and spatial extent of scar tissue, total scar score, and quantified percent left ventricular scar tissue. MRI data were related to the presence/absence of Q waves on the ECG. Q waves were present in 39 patients (57%). Univariate analysis identified transmurality, spatial extent, total scar score, and quantified percent scar tissue as predictors of Q waves. Multivariate analysis demonstrated that quantified percent scar tissue was the single best predictor of Q waves on the ECG. A cut-off value of 17% infarcted tissue of the left ventricle yielded a sensitivity and specificity of 90% to predict the presence/absence of Q waves. When quantified percent scar tissue was removed from the model, spatial extent of infarction was the best predictor. Thus, Q waves on the ECG correlate best with quantified percent scar tissue on contrast-enhanced MR images.

Head-to-Head comparison between Contrast-Enhanced magnetic resonance imaging and dobutamine magnetic resonance imaging in men with ischemic cardiomyopathy

Contrast-enhanced magnetic resonance imaging (MRI) can predict functional recovery after revascularization. Segments with small, subendocardial scars have a large likelihood of recovery, and segments with transmural infarction have a small likelihood of recovery. Segments with an intermediate extent of infarction have an intermediate likelihood of recovery, and therefore, additional information is needed. Accordingly, the transmurality of infarction on contrast-enhanced MRI was compared with low-dose dobutamine MRI to further define viability in 48 patients. Regional contractile dysfunction was determined by cine MRI at rest (17-segment model), and contractile reserve was determined using low-dose dobutamine infusion. Contrast-enhanced MRI was performed to assess the extent of scar tissue. A total of 338 segments (41%) were dysfunctional, with 61% having contractile reserve. Most segments (approximately 75%) with small, subendocardial scars (hyperenhancement scores 1 or 2) had contractile reserve, whereas contractile reserve was not frequently (17%) observed in segments with transmural infarction (hyperenhancement score 4) (p <0.05). Of segments with an intermediate infarct transmurality (hyperenhancement score 3), contractile reserve was observed in 42%, whereas 58% did not have contractile reserve. In conclusion, the agreement between contrast-enhanced MRI and low-dose dobutamine MRI is large in the extremes (subendocardial scars and transmural scars), and contrast-enhanced MRI may be sufficient to assess the likelihood of the recovery of function after revascularization. However, 61% of segments with an intermediate extent of scar tissue on MRI have contractile reserve and 39% lack contractile reserve. In these segments, low-dose dobutamine MRI may be needed to optimally differentiate myocardium with large and small likelihoods of functional recovery after revascularization.

Magnetic resonance imaging for the assessment of myocardial viability.

The identification of myocardial viability in the setting of left ventricular (LV) dysfunction is crucial for the prediction of functional recovery following revascularization. Although echocardiography, positron emission tomography (PET), and nuclear imaging have validated roles, recent advances in cardiac magnetic resonance (CMR) technology and availability have led to increased experience in CMR for identification of myocardial viability. CMR has unique advantages in the ability of magnetic resonance spectroscopy (MRS) to measure subcellular components of myocardium, and in the image resolution of magnetic resonance proton imaging. As a result of excellent image resolution and advances in pulse sequences and coil technology, magnetic resonance imaging (MRI) can be used to identify the transmural extent of myocardial infarction (MI) in vivo for the first time. This review of the role of CMR in myocardial viability imaging describes the acute and chronic settings of ventricular dysfunction and concepts regarding the underlying pathophysiology. Recent advances in MRS and MRI are discussed, including the potential for dobutamine MRI to identify viable myocardium and a detailed review of the technique of delayed gadolinium (Gd) contrast hyperenhancement for visualization of viable and nonviable myocardium.

Noninvasive, quantitative assessment of left ventricular function in ischemic cardiomyopathy

Background Coronary artery disease characteristically impacts left ventricular (LV) function on a regional basis, although ultimately global function may be affected as well. Echocardiography is commonly clinically used for the assessment of regional function; however, it is only semiquantitative and in its current iteration is only two-dimensional in nature. Magnetic resonance imaging (MRI) with tissue tagging offers the possibility for noninvasive, three-dimensional (3D) assessment of transmural and segmental left ventricular strain and, thereby, function. Accordingly, we have explored methodologies to accurately and quantitatively characterize regional systolic function in three dimensions in patients with ischemic heart disease using MRI. Materials and methods MRI radiofrequency tissue tagging was performed at rest and during dobutamine administration (10 mg/kg/min) on 10 normal volunteers (age: 26 ± 6) and 8 patients with severe ischemic cardiomyopathy (age: 60 ± 5, EF 26 ± 11%). Three-dimensional global and regional systolic strain calculations were made based on 3D myocardial point displacements and compared with conventional measures. Results Global left ventricular strains were significantly decreased in ischemic patients at rest (0.14 ± 0.04 versus 0.25 ± 0.02, P < 0.001) and with dobutamine (0.14 ± 0.03 versus 0.29 ± 0.03, P < 0.001). In the regional analysis (216 LV wall segments) this methodology accurately differentiated normal from abnormally contracting regions. Conclusions Noninvasive dobutamine MRI tissue tagging with calculation of 3D regional strains has significant promise as a clinical tool which is capable of the identification, quantification, and display of regionally varying ventricular function.

The histology of viable and hibernating myocardium in relation to imaging characteristics

ObjectivesThis study characterizes the histology of myocardium predicted to be hibernating using three different imaging techniques to explain the discordance among them. BackgroundBoth radionuclide and functional imaging techniques were used to assess myocardial hibernation. The former have high sensitivity and the latter high specificity for predicting functional recovery. MethodsNineteen patients underwent thallium-201 and 99m-technetium tetrofosmin myocardial perfusion imaging, and dobutamine magnetic resonance imaging (MRI), prior to coronary bypass grafting. Criteria for predicted hibernation for each technique were defined before operation. Postoperative criteria for scar and true hibernation were also defined. Biopsies were analyzed for myocyte volume fraction (MVF), glycogen deposition and pathologic cell features. ResultsThallium was most sensitive in predicting hibernation (88%) and MRI most specific (84%); and, although there was good agreement between thallium and tetrofosmin (85%), agreement between MRI and thallium (59%) or tetrofosmin (59%) was poor. For each technique, MVF was higher in segments predicted to be hibernating rather than scar (p < 0.05). The MVF was higher where both thallium and MRI predicted hibernation (0.77 ± 0.07) than in segments predicted by thallium alone (0.69 ± 0.13, p < 0.05). Proven hibernating segments had a higher MVF than scar (0.72 ± 0.11 vs. 0.6 ± 0.26, p < 0.05). ConclusionsPreservation of myocyte fraction is an important determinant of functional recovery after revascularization. A higher myocyte fraction is required to maintain contractile reserve than to achieve significant tracer uptake. This explains the higher sensitivity of radionuclide imaging compared with dobutamine MRI in the identification of myocardial hibernation.

10.37 Comparison of dual dose dobutamine magnetic resonance imaging and positron emission tomography in assessing myocardial viability

10.37 Comparison of dual dose dobutamine magnetic resonance imaging and positron emission tomography in assessing myocardial viability

10.37 Comparison of dual dobutamine magnetic resonance imaging and positron emission tomography in assessing myocardial viability

10.37 Comparison of dual dobutamine magnetic resonance imaging and positron emission tomography in assessing myocardial viability

Dobutamine magnetic resonance imaging with myocardial tagging quantitatively predicts improvement in regional function after revascularization

Segmental contractile reserve measured by dobutamine magnetic resonance imaging quantitatively predicts improvement in end-systolic wall thickness after revascularization. Segments with end-systolic wall thickness <7 mm at rest do not demonstrate contractile reserve or improve after revascularization.

Validation of low-dose dobutamine magnetic resonance imaging for assessment of myocardial viability after infarction by serial imaging

Cine magnetic resonance imaging with low-dose dobutamine stimulation allows prediction of viability after infarction with an accuracy of 80%. In akinetic segments, however, viability tends to be underestimated.

Dobutamine Magnetic Resonance Imaging Predicts Contractile Recovery of Chronically Dysfunctional Myocardium After Successful Revascularization

Objectives. This study sought to evaluate whether myocardial viability, as assessed by magnetic resonance imaging (MRI), reliably predicts postrevascularization left ventricular (LV) recovery.Background. Compared with positron emission tomographic findings, MRI has proved to be a reliable technique for the identification of residual myocardial viability. However, the predictive accuracy of MRI-assessed preserved end-diastolic wall thickness (DWT) and dobutamine-induced systolic wall thickening (SWT) for LV functional recovery has not yet been evaluated.Methods. Rest and low dose dobutamine MRI was performed in 43 patients with a chronic infarct (≥4 months since ischemic event) and LV dysfunction who had undergone revascularization of the infarct-related vessel. On the basis of segmental evaluation of corresponding short-axis tomograms, infarct regions were graded viable by MRI if 1) DWT was ≥5.5 mm, and 2) dobutamine-induced SWT was ≥2 mm in ≥50% of dysfunctional segments related to the infarct region. Functional recoverywas defined as SWT ≥2 mm in ≥50% of infarct-related segments at rest 4 to 6 months after successful revascularization.Results. Recovery of regional SWT could be observed in 27 (63%) of 43 patients. Comparison MRI grading before and after revascularization indicated that dobutamine-induced SWT was a better predictor of LV functional recovery (sensitivity 89%, specificity 94%) than was preserved DWT (sensitivity 92%, specificity 56%). Segments that remained akinetic after revascularization had significantly lower DWT (6.0 ± 3.1 mm [n = 219] vs. 9.8 ± 2.6 mm [n = 188], p < 0.001) than those with improved SWT. Left ventricular ejection fraction increased significantly in patients with dobutamine-induced SWT than in those with no contractile reserve (14 ± 9% vs. 3 ± 9%, p < 0.0002), and the magnitude of this increase was correlated with the number of dobutamine-responsive segments per infarct region (r = 0.68, p < 0.0001).Conclusions. Quantitative assessment of dobutamine-induced SWT in chronic infarcts by MRI is a highly accurate predictor of LV functional recovery, and the presence of significantly reduced DWT reliably indicates irreversible myocardial damage. Therefore, dobutamine stress testing for the assessment of myocardial viability can be restricted to patients with preserved DWT.

Breath-Hold Dobutamine Magnetic Resonance Myocardial Tagging: Normal Left Ventricular Response

Analysis of the changes in myocardial deformation produced by adrenergic stress has been limited by the imaging techniques used. We used rapid magnetic resonance imaging (MRI) myocardial tagging to map the dose-dependent response to incremental dobutamine in the normal human left ventricle. Thirteen volunteers underwent breath-hold tagged cine MRI during dobutamine infusion. Images were acquired throughout systole to a peak dose of 20 μg/kg/min. End-systolic percent circumferential shortening (%S) was measured at 3 transmural locations and 4 circumferential locations at 3 long-axis positions. Mean circumferential shortening velocity (CSV) was also calculated at each location and dose. Mean %S reached a maximum of 26 ± 3% at 10 μg/kg/min compared with 21 ± 4% at baseline (p <0.003). Peak %S was reached by 10 μg/kg/min before a significant increase in heart rate or blood pressure and was unchanged at higher doses. In contrast, CSV increased linearly with dobutamine dose from 4.4 ± 0.9 mm/s at baseline to 9.8 ± 1.4 mm/s at 20 μg/kg/min (p <0.0001). Breath-hold tagged dobutamine MRI is safe and effective in detecting regional and transmural changes in function during incremental dobutamine. CSV increased continuously across the dobutamine dose range. At low dose (≤10 μg/kg/min) %S increased without any change in blood pressure or heart rate. Maintenance of peak %S beyond 10 μg/kg/min in the presence of decreasing systolic intervals resulted from a continued increase in CSV. Thus, CSV may be the preferred measure of contractile function during dobutamine stimulation in human myocardium.

Wall thickening at rest and contractile reserve early after myocardial infarction: correlation with myocardial perfusion and metabolism.

Abnormalities in wall thickening and their reaction to stimulation can be studied by magnetic resonance imaging. To analyse the relationship between these abnormalities and changes in myocardial perfusion and fatty acid metabolism. Fifteen patients with a myocardial infarction underwent low-dose dobutamine magnetic resonance imaging to assess their wall thickening and contractile reserve, and technetium-99m sestamibi (MIBI) and beta-methyl-iodophenyl-pentadecanoic acid (BMIPP) single-photon emission tomography to assess their myocardial perfusion and fatty acid uptake. For nine segments per patient, the wall thickening was scored as normal, hypokinetic or akinetic, and the myocardial perfusion as normal (> 65%), mildly to moderately reduced (35-65%) or severely reduced (< 35%). Abnormalities in fatty acid uptake were compared with the myocardial perfusion and defined as matched (difference < or = 10%) or mismatched (difference > 10%) reduction. Thirty-four segments had abnormal wall thickening (13 hypokinetic and 21 akinetic). The wall thickening at rest was significantly related to the uptake of MIBI (P < 0.001), but not to abnormalities in the uptake of BMIPP. All of the akinetic segments had an abnormal uptake of MIBI (15 severely and six mildly to moderately reduced), whereas 7 of 13 hypokinetic segments had a normal and five a midly to moderately reduced uptake. A significant relationship between abnormalities of fatty acid metabolism and the contractile reserve was also found (P < 0.002): 14 of 16 segments with and only six of 18 without contractile reserve had a mismatched reduction in uptakes of MIBI and BMIPP. This study confirms the relationship between the wall thickening at rest and the residual perfusion after infarction. On the other hand, the contractile reserve, which is an accepted indicator of the viability of the infarct region, is associated strongly with abnormalities of fatty acid metabolism.

Comparison of Dobutamine Transesophageal Echocardiography and Dobutamine Magnetic Resonance Imaging for Detection of Residual Myocardial Viability

A dobutamine-induced contraction reserve in akinetic but viable myocardium, observed by echocardiography or magnetic resonance imaging (MRI), is a reliable indicator of myocardial viability. However, the comparative diagnostic accuracy of these 2 techniques is unknown. Therefore, 43 patients with myocardial infarction (infarct age ≥4 months) and regional akinesia underwent dobutamine transesophageal echocardiography (TEE) and dobutamine MRI (10 μg dobutamine/min/kg). Both imaging techniques were compared with the reference standard 18F-fluorodeoxyglucose positron emission tomography (FDG PET). An infarct region was considered viable if a dobutamine contraction reserve could be assessed visually by TEE or quantitatively by MRI in ≥50% of segments graded “a” or dyskinetic at rest. Infarct regions were graded viable by PET if FDG uptake was ≥50% of the maximal FDG uptake in a region with normal wall motion by left ventriculography. A dobutamine contraction reserve was found in 21 of 43 patients (49%) by TEE and MRI. A viable infarct region by FDG PET was diagnosed in 26 of 43 patients (60%). FDG uptake and dobutamine TEE were concordant in 36 of 43 patients (84%) and dobutamine MRI and FDG PET were concordant in 38 of 43 patients (88%). Sensitivity and specificity of dobutamine TEE and dobutamine MRI for FDG PET-defined myocardial viability were 77% versus 81% and 94% versus 100%, respectively. Both imaging techniques yielded similar results for the detection of myocardial viability as defined by FDG uptake, with a slightly higher sensitivity and specificity for the quantitatively evaluated dobutamine contraction reserve by MRI. (Am J Cardiol 1996;78:415–419)

Low-dosage dobutamine magnetic resonance imaging as an alternative to echocardiography in the detection of viable myocardium after acute infarction

The objective of this study was the evaluation of the feasibility of magnetic resonance (MR) imaging of the heart with low-dosage dobutamine stimulation for the detection of viability after acute myocardial infarction. Gradient echo MR images were obtained in 37 patients with recent myocardial infarction. Images of wall motion abnormalities and their reaction to low-dosage dobutamine stimulation were analyzed and compared with two-dimensional echocardiograms. Follow-up echocardiography at 3 to 6 months was available in 24 patients. Concordant diagnosis of viability between the two techniques was obtained in 30 (81%) of 37 patients. MR correctly predicted evolution of wall motion in 19 (79%) of 24 patients, a result not significantly different from echocardiography: 20 (83%) of 24. It was concluded that low-dosage dobutamine MR imaging is a safe alternative to echocardiography to predict recovery of wall motion abnormalities after myocardial infarction.

929-122 Detection of Hybernating Myocardium by Dobutamine Magnetic Resonance Imaging

Identification of hybernating myocardium (HM) by magnetic resonance imaging (MRI), is controversial. Trying to optimize MRI results we studied 45 pts with coronary artery disease (CAD) and depressed left ventricular wall motion (LVWM) and ejection fraction (LVEF) at baseline angiogram (ANGlO). MRI before and after a low doses infusion of dobutamine (00,5 mcglkg/min). MRI defined LVWM and LVEF correlated with those of ANGlO (r = 0.767 and r = 0.843, respectively). After DO injection T1 signal increased in 27 (65 ± 15 vs. 98 ± 9, p = 0.03) pts whereas 18 pts had non significant changes (58 ± 12 vs. 52 ± 12, P = NS). All pts underwent coronary bypass surgery and repeated MRI before hospital discharge. LVEF (0.32 vs 0.45, p = 0.03) and LVWM (-2.6 ± 0.8 vs 0.8 ± 0.4 P = 0.04) improved in the 27 pts with T1 changes. None of the others improved LVEF (0.34 vs 0.36, P = NS) or LVWM (-2.4 ± 1.2 vs. -1.8 ± 0.7, P = NS). Conclusion; DO-MRI seems to be an effective manner to identify HM in pts with chronic CAD and depressed LV contractility.

Magnetic resonance imaging during dobutamine stress for detection and localization of coronary artery disease. Quantitative wall motion analysis using a modification of the centerline method.

Quantitative measurement of wall motion is essential to assess objectively the functional significance of coronary artery disease. We developed a quantitative wall thickening analysis on stress magnetic resonance images. This study was designed to assess the clinical value of magnetic resonance imaging (MRI) during dobutamine stress for detection and localization of myocardial ischemia in patients with suspected coronary artery disease. Thirty-nine consecutive patients with clinically suspected coronary artery disease referred for coronary arteriography and 10 normal volunteers underwent gradient-echo MRI at rest and during peak dobutamine stress (infusion rate, 20 micrograms.kg-1.min-1). MRI was performed in the short-axis plane at four adjacent levels. Display in a cine loop provided a qualitative impression of regional wall motion (cine MRI). A modification of the centerline method was applied for quantitative wall motion analysis by means of calculation of percent systolic wall thickening. Short-axis cine MRI images were analyzed at 100 equally spaced chords constructed perpendicular to a centerline drawn midway between the end-diastolic and end-systolic contours. Dobutamine MRI was considered positive for coronary artery disease if the percent systolic wall thickening of more than four adjacent chords was < 2 SD below the mean values obtained from the normal volunteers. The overall sensitivity of dobutamine MRI for the detection of significant coronary artery disease (diameter stenosis > or = 50%) was 91% (30 of 33), specificity was 80% (5 of 6), and accuracy was 90% (35 of 39). The sensitivity for identifying one-vessel disease was 88% (15 of 17), for two-vessel disease 91% (10 of 11), and for three-vessel disease 100% (5 of 5). The sensitivity for detection of individual coronary artery lesions was 75% for the left anterior descending coronary artery, 87% for the right coronary artery, and 63% for the left circumflex coronary artery. Dobutamine MRI clearly identifies wall motion abnormalities by quantitative analysis using a modification of the centerline method. Dobutamine MRI is an accurate method for detection and localization of myocardial ischemia and may emerge as a new noninvasive approach for evaluation of patients with known or suspected coronary artery disease.