Irreversible myocardial injury: assessment with cardiovascular delayed-enhancement MR imaging and comparison of 1.5 and 3.0 T--initial experience.
OBJECTIVE
To prospectively compare visualization and quantification of irreversible myocardial injury in patients with chronic myocardial infarction at 1.5- and 3.0-T magnetic resonance (MR) imaging.


METHODS
The institutional research ethics committee approved the study. Participants gave written informed consent. Sixteen male patients (mean age, 66 years +/- 13 [standard deviation]) with myocardial infarction were imaged with the same sequence by the same operator at 1.5 and 3.0 T. After cine imaging, a bolus of gadodiamide was administered. Short-axis images of entire left ventricle (LV) were acquired with a breath-hold T1-weighted segmented inversion-recovery turbo fast low-angle shot (FLASH) sequence. Agreement for myocardial hyperenhancement (HE) mass between field strengths was assessed with Bland-Altman method; agreement for detection and transmural extent of HE was assessed with kappa statistics. Intra- and interobserver reproducibility of mass and transmural extent of HE were assessed at 1.5 and 3.0 T.


RESULTS
Bland-Altman analysis revealed no systematic bias (mean difference, 0.2 g; 95% confidence interval: -0.7 g, 1.2 g) and acceptable limits of agreement (-3.3 to 3.8 g) between field strengths for HE mass. HE mass measurements were strongly correlated (R(2) = 0.99); there was no significant difference in measurements at 1.5 and 3.0 T (28.1 g +/- 15.7 [22.6% +/- 10.9 of LV mass] vs 27.8 g +/- 15.7 [22.3% +/- 10.7 of LV mass], respectively; P = .599). For all segments, there was a high degree of agreement for HE detection (kappa = 0.90) and transmural grade (kappa = 0.79) between field strengths. Intra- and interobserver variability were low between both field strengths. Initial inversion time selected to null the signal of normal myocardium at 3.0 T was 57 msec +/- 20 longer than at 1.5 T (P < .01).


CONCLUSIONS
By using the same turbo FLASH MR pulse sequence, there was strong agreement in mass and transmural extent of myocardial HE between 1.5 and 3.0 T.
Cheng
Adrian S H
AS
University of Oxford Centre for Clinical Magnetic Resonance Research and Department of Cardiovascular Medicine, John Radcliffe Hospital, Headley Way, Headington, Oxford OX3 9DU, England.
Robson
Matthew D
MD
Neubauer
Stefan
S
Selvanayagam
Joseph B
JB
D000368:Aged; D002908:Chronic Disease; D003287:Contrast Media / Q000008:administration & dosage; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009203:Myocardial Infarction / Q000150:complications / Q000175:diagnosis*; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000209:etiology
D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA