Work

Impact of transmurality and location on the diagnostic performance of 13N-ammonia positron emission tomography in the detection of myocardial fibrosis – A hybrid positron emission tomography/magnetic resonance study

Year: 2025

Type: article

Abstract: BACKGROUND: The influence of fibrosis transmurality and location on the diagnostic performance of positron emission tomography (PET) myocardial perfusion imaging (MPI) for detecting myocardial fibrosis remains unclear. METHODS AND RESULTS: One hundred patients with suspected or known coronary artery disease (n = 50) or with a history of myocarditis (n = 50) underwent simultaneous cardiac magnetic resonance (CMR) and 13N-ammonia PET imaging on a hybrid positron emission tomography/magnetic resonance (PET/MR) device. CMR served as the reference with late gadolinium enhancement defining fibrosis of the left ventricular myocardium. PET MPI was assessed for fibrosis qualitatively (i.e. visually), semiquantitatively, and quantitatively (both threshold-based). From CMR, for every segment, the transmurality and location (subendocardial, midmyocardial, or subepicardial) of fibrosis were recorded. The sensitivity and specificity of qualitatively analyzed PET to detect fibrosis were 83.6% and 84.9% per patient and 52.9% and 96.4% per segment, respectively, outperforming the threshold-based semiquantitative and quantitative analyses. On a per-segment basis, the sensitivity of PET was increasing with transmurality and was dependent on location with higher sensitivities for subendocardial than subepicardial or midmyocardial fibrosis (P < .001). Overall median fibrosis extent, as depicted by PET, was significantly smaller than by CMR (2.0 [IQR 1.0-5.0] vs 3.0 [IQR 2.0-6.0] segments, P < .001). CONCLUSIONS: PET yields high sensitivity for the detection of left ventricular (LV) myocardial fibrosis of ischemic or inflammatory etiology on a per-patient basis. However, compared to CMR, the overall fibrosis extent is significantly underestimated because, on a segmental level, sensitivities are significantly lower for fibrosis with lower transmurality and those located subepicardial and midmyocardial, as compared to subendocardial.

Source: Journal of Nuclear Cardiology

DOI: 10.1016/j.nuclcard.2025.102172