Sixty-four-MSCT in the characterization of porcine acute and subacute myocardial infarction: determination of transmurality in comparison to magnetic resonance imaging and histopathology.
OBJECTIVE
The aim of this study was to assess the accuracy of MSCT in characterizing myocardial infarction (MI) and, thereby, determine the extent of early perfusion defect (ED), microvascular obstruction (MO) and transmural depth of late enhancement (LE) in comparison to MRI and histology.


METHODS
Seven pigs were studied with MSCT (Somatom Sensation 64) and MRI (Magnetom Sonata) a median 1 and 21 days following temporary occlusion of a diagonal branch and creation of small reperfused infarction. For depiction of ED, CT images were acquired in the early arterial phase and following 35 s; LE and MO were evaluated on images obtained at 3, 5, 10 and 15 min. Thereby, a bolus/low-flow contrast injection protocol was used. Triphenyltetrazolium-chloride (TTC) stain and histology were obtained. Volumes of enhancement patterns were assessed as percentage of the ventricle and compared by Bland-Altman analysis. Segmental co-localization and graded transmurality was evaluated with weighted-kappa-test.


RESULTS
Close spatial agreement was observed for MRI-MO and MSCT-MO (bias=0.55; CI=-1.49 to 2.60 at 5 min MSCT), TTC and MSCT-LE (bias=-1.28; CI=-3.76 to 1.19) or MRI-LE and MSCT-LE (bias=-0.79; CI=-4.19 to 2.60). There was good segmental co-localization for MO (weighted kappa=0.93) and high agreement for transmural extent of TTC, MRI-LE and MSCT-LE (weighted kappa=0.84 TTC versus MSCT; 0.86 MRI versus MSCT). Arterial and 35s ED significantly underestimated infarct size and showed poor segmental or transmural agreement (weighted kappa=0.33; 0.44).


CONCLUSIONS
MSCT late-scans not only reliably depict size of MO and LE in acute or subacute infarct phases but, moreover, allow for accurate determination of LE transmurality.
Brodoefel
H
H
Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany. h.brodoefel@t-online.de
Klumpp
B
B
Reimann
A
A
Fenchel
M
M
Heuschmid
M
M
Miller
S
S
Schroeder
S
S
Claussen
C
C
Scheule
A M
AM
Kopp
A F
AF
D000704:Analysis of Variance; D000818:Animals; D004396:Coloring Agents; D003287:Contrast Media; D004195:Disease Models, Animal; D019786:Gadolinium DTPA; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000473:pathology; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000473:pathology*; D015588:Observer Variation; D015203:Reproducibility of Results; D012107:Research Design; D012680:Sensitivity and Specificity; D013552:Swine; D013778:Tetrazolium Salts; D014057:Tomography, X-Ray Computed
D004396:Coloring Agents; D003287:Contrast Media; D013778:Tetrazolium Salts; C009591:triphenyltetrazolium; D019786:Gadolinium DTPA