Accuracy of cardiovascular magnetic resonance in myocarditis: comparison of MR and histological findings in an animal model

Abstract

BackgroundBecause Endomyocardial Biopsy has low sensitivity of about 20%, it can be performed near to myocardium that presented as Late Gadolinium Enhancement (LGE) in cardiovascular magnetic resonance (CMR). However the important issue of comparing topography of CMR and histological findings has not yet been investigated. Thus the current study was performed using an animal model of myocarditis.ResultsIn 10 male Lewis rats Experimental Autoimmune myocarditis was induced, 10 rats served as control. On day 21 animals were examined by CMR to compare topographic distribution of LGE to histological inflammation. Sensitivity, specificity, positive and negative predictive values for LGE in diagnosing myocarditis were determined for each segment of myocardium. Latter diagnostic values varied widely depending on topographic distribution of LGE and inflammation as well as on the used CMR sequence. Sensitivity of LGE was up to 76% (left lateral myocardium) and positive predictive values were up to 85% (left lateral myocardium), whereas sensitivity and positive predictive value dropped to 0-33% (left inferior myocardium).ConclusionsTopographic distribution of LGE and histological inflammation seem to influence sensitivity, specifity, positive and negative predictive values. Nevertheless, positive predictive value for LGE of up to 85% indicates that Endomyocardial Biopsy should be performed "MR-guided". LGE seems to have greater sensitivity than Endomyocardial Biopsy for the diagnosis of myocarditis.

Non-invasive assessment of experimental autoimmune myocarditis in rats using a 3 T clinical MRI scanner

“…rats on Day 21 after the induction of EAM, mapped the distribution of LGE using a seven-segment model of the LV, and reported that LGE was located mainly in the anterior and lateral LV walls, and was correlated with histopathology findings. 3,4 In the present study, CMR accurately identified the location and the extent of myocardial damage, which corresponded with the histopathological picture of myocarditis. These findings also correlate with typical findings in humans with myocarditis, showing a subepicardial distribution of LGE mainly in basal and mid-infero-lateral segments.…”

“…Significantly, the present study expands upon previous studies by providing new findings on myocarditis in a rat model. 3,4 First, in addition to…”

“…Secondly, we used a clinical LV segmentation model to map function and fibrosis of the injured myocardial regions, 13 with better sensitivity, specificity, and predictive accuracy (87-91%), compared with previous reports. 3 Thirdly, we imaged rats without slowing their heart rate, thereby avoiding potential influence on cardiac function. Finally, our study also included detailed comparisons with serial 2D echocardiography examinations and histopathology.…”

“…Korkusuz et al 3,4 have already taken important steps in this direction by using late gadolinium-enhanced (LGE) MRI in a rat model of myocarditis using a 1.5 T scanner. We sought to extend this approach, where, in addition to LGE MRI at a single time point, we investigated cine MRI of LV volumes and ejection fraction and performed serial measurements of disease progression.…”

Usefulness of Rabbit Anti-thymocyte Globulin in Patients With Giant Cell Myocarditis

“…CMR has also demonstrated excellent diagnostic capability for patients with suspected acute myocarditis, and EMB guided by CMR results may enhance the positive predictive value of this technique. 17,18 In our group, 5 of the patients had a CMR, but only in 1 of them, the most clinically stable case, it was part of the acute diagnostic process. All the other patients had the CMR after immunosuppression treatment and >10 days after admission.…”