Acute myocardial infarction: evaluation with first-pass enhancement and delayed enhancement MR imaging compared with 201Tl SPECT imaging.
OBJECTIVE
To evaluate acute myocardial infarction by using first-pass enhancement (FPE) and delayed enhancement (DE) magnetic resonance (MR) imaging compared with thallium 201 ((201)Tl) single photon emission computed tomography (SPECT).


METHODS
Contrast material-enhanced FPE MR, inversion-recovery DE MR, and rest-redistribution (201)Tl SPECT images were obtained in 60 consecutive patients (53 men, seven women; mean age [+/- SD], 56 years +/- 13; range, 30-78 years) at 6 days +/- 3 after reperfused first myocardial infarction. Presence of microvascular obstruction was determined on FPE MR images. Infarct size was defined on DE MR images as percentage of left ventricular (LV) area and compared with uptake defect on redistribution (201)Tl SPECT images. Differences in continuous data were analyzed with Student t test. Linear regression and Bland-Altman analysis were used to compare measurements of infarct size.


RESULTS
Mean infarct size was not significantly different between DE MR imaging (20.7% +/- 11.5% of LV area) and (201)Tl SPECT (19.4% +/- 14.3% of LV area; P =.26); good correlation (r = 0.73; P <.001) and agreement were found, with a mean difference of +1.3% +/- 9.8% of LV area. (201)Tl SPECT failed to depict infarct in six (20%) of 30 patients with inferior myocardial infarction (mean size, 6.4% +/- 5.7% of LV area on DE MR images), whereas DE MR images showed the infarct in all patients (P <.01). FPE MR images depicted microvascular obstruction in 23 (38%) of 60 patients; these patients had larger infarctions at DE MR imaging than did patients without microvascular obstruction (30.4% +/- 9.0% vs 15.1% +/- 8.4% of LV area, P <.001). (201)Tl SPECT showed larger infarcts in patients with microvascular obstruction (26.7% +/- 16.2% vs 15.0% +/- 11.2% of LV area, P <.01).


CONCLUSIONS
Good correlation and agreement with (201)Tl SPECT indicate DE MR imaging may be used to estimate infarct size 6 days after reperfused acute myocardial infarction. DE MR imaging is more sensitive for detection of inferior infarction than is (201)Tl SPECT. Patients with microvascular obstruction on FPE MR images have larger infarcts.
Lund
Gunnar K
GK
Department of Cardiology, University Hospital Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. glund@uke.uni-hamburg.de
Stork
Alexander
A
Saeed
Maythem
M
Bansmann
Martin P
MP
Gerken
Jann H
JH
Müller
Vika
V
Mester
Janos
J
Higgins
Charles B
CB
Adam
Gerhard
G
Meinertz
Thomas
T
D000328:Adult; D000368:Aged; D003287:Contrast Media; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000473:pathology; D005260:Female; D019786:Gadolinium DTPA; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D008833:Microcirculation / Q000473:pathology; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000628:therapy; D009204:Myocardial Revascularization; D009206:Myocardium / Q000473:pathology; D012680:Sensitivity and Specificity; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon
D003287:Contrast Media; D013794:Thallium Radioisotopes; D019786:Gadolinium DTPA