[Quantification of microvascular obstruction in acute myocardial infarction using cardiac MRI].
OBJECTIVE
Microvascular obstruction (MO) and the extent of infarction are important prognostic factors in acute myocardial infarction. Our study aimed to investigate the effect of the time interval between contrast administration and image acquisition on the quantification of microvascular obstruction and myocardial infarction.


METHODS
50 consecutive patients with acute myocardial infarction (40 male, mean age 58.1 +/- 11.7 years) treated by percutaneous coronary revascularization resulting in a grade 3 flow according to the thrombolysis in myocardial infarction flow classification were examined on a 1.5 T MR scanner within the first 5 days after infarction. 2, 5, 10, and 20 minutes after I.V. administration of 0.2 mmol/kg per kg body weight of Gadodiamid (Omniscan), GE Healthcare Buchler, Germany), a single shot IR-SSFP sequence (TR 2.4 ms, TE 1.08 ms, TI 180 - 280 ms, FA 50 degrees) covering the entire left ventricle was acquired. Areas of MO and myocardial infarction were measured for all times after contrast injection (p. i.).


RESULTS
MO was detected in 32 of 50 patients two minutes p. i., while 23 patients showed evidence of MO (p = 0.002) 20 min. p. i. In all patients with MO, the extent of MO decreased over time (7.4 +/- 9.0 % of the LV myocardium 2 min. p. i. vs. 2.4 +/- 4.6 % 20 min. p. i. p < 0.0001). The area of myocardial infarction increased from 13.9 +/- 13.5 % 2 min. p. i. to 18.6 +/- 14.2 % 10 min. p. i. (p < 0.0001), and then remained unchanged (18.7 +/- 14.3 % at 20 min. p = 0.57).


CONCLUSIONS
Our study shows that the time delay between contrast media injection and image acquisition has a significant impact on the delimitable extent of MO and infarct size.
Nassenstein
K
K
Institut für Diagnostische und Interventionelle Radiologie und Neuroradiologie, Universitätsklinikum Essen. Kai.Nassenstein@uni-due.de
Waltering
K
K
Hollenhorst
M
M
Bruder
O
O
Schlosser
T
T
Hunold
P
P
Barkhausen
J
J
D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics; D017023:Coronary Angiography / Q000379:methods*; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy; D009206:Myocardium / Q000473:pathology; D054318:No-Reflow Phenomenon / Q000175:diagnosis*; D015912:Thrombolytic Therapy; D016896:Treatment Outcome
D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA