Multidetector computed tomography for characterization of calcium deposits in reperfused myocardial infarction.
BACKGROUND
Calcium overload is a major cause of reperfusion myocardial injury. Multidetector computed tomography (MDCT) has been previously used in visualizing coronary artery calcium, but not calcium deposits in reperfused infarction.


OBJECTIVE
To assess the ability of MDCT to 1) noninvasively visualize and characterize calcium deposits in reperfused infarcts, and 2) monitor regional wall swelling, regional systolic wall thickening, and infarct resorption.


METHODS
Reperfused myocardial infarcts were created in seven pigs by 2-hour occlusion of the left anterior descending coronary artery (LAD) after coronary catheterization. A 64-slice MDCT scanner was used for non-contrast images to depict calcium deposits. Furthermore, cine and delayed contrast-enhanced (DE) MDCT imaging were acquired to assess the chronological changes (2-4 hours, 1 week, and 8 weeks) in regional wall swelling, systolic wall thickening, and infarct size.


RESULTS
Non-contrast MDCT images depicted calcium deposits as "hot-spots." Attenuation of calcium deposits was greater (89+/-6 Hounsfield units [HU]) than remote myocardium (36+/-3 HU; P<0.05). Calcium deposits were not evident at 2-4 hours and were substantially smaller at 8 weeks compared to 1 week. Correlations were found between the extent of calcium deposits, ejection fraction (R=0.81), and infarction size (R=0.70). Cine MCDT images demonstrated transient wall swelling (edema formation and resorption) at 2-4 hours and differences in regional systolic wall thickening among infarcted, peri-infarcted, and remote myocardium. Calcium-specific von Kossa stain confirmed the presence of calcium deposits in infarcted myocardium.


CONCLUSIONS
64-slice MDCT has the potential to demonstrate the progression and regression of calcium deposits, interstitial edema, and infarction. The presence of calcium deposits was transient and associated with reperfused recent infarction. The extent of calcium deposits was positively correlated with infarction size and negatively with global left-ventricular function.
Carlsson
M
M
Department of Radiology and Biomedical Imaging, University of California San Francisco, California 94134-0628, USA.
Ursell
P C
PC
Saloner
D
D
Saeed
M
M
D015906:Angioplasty, Balloon, Coronary; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003287:Contrast Media; D006651:Histocytochemistry; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D034421:Sus scrofa; D014057:Tomography, X-Ray Computed; D016277:Ventricular Function, Left
D003287:Contrast Media; D002118:Calcium