A Two-stage Cardiac PET and Late Gadolinium Enhancement MRI Co-registration Method for Improved Assessment of Non-ischemic Cardiomyopathies Using Integrated PET/MR

PurposeRespiratory motion causes mismatches between PET images of the myocardium and the corresponding cardiac MR images in cardiac integrated PET/MR. The mismatch may affect the attenuation correction and the diagnosis of non-ischemic cardiomyopathies. In this study, we present a two-stage cardiac PET and MR Late Gadolinium Enhancement (LGE) co-registration method, which seeks to improve diagnostic accuracy of non-ischemic cardiomyopathies via better image co-registration using an integrated whole-body PET/MR system.MethodsThe proposed PET and LGE two-stage co-registration method was evaluated through comparison with one-stage direct co-registration and no-registration. One hundred and ninety-one slices of LGE and forty lesions were studied. Two trained nuclear medicine physicians independently assessed the displacement between LGE and PET to qualitatively evaluate the co-registration quality. The changes of the mean SUV in the normal myocardium and the LGE-enhanced lesions before and after image co-registration were measured to quantitatively evaluate the accuracy and value of image co-registration.ResultsThe two-stage method had an improved image registration score (4.93±0.89) compared with the no-registration method (3.49±0.84, p value <0.001) and the single-stage method (4.23±0.81, p value <0.001). Furthermore, the two-stage method led to increased SUV value in the myocardium (3.87±2.56) compared with the no-registration method (3.14±1.92, p value <0.001) and the single-stage method (3.32±2.16, p value <0.001). The mean SUV in the LGE lesion significantly increased from 2.51±2.09 to 2.85±2.35 (p value<0.001) after the two-stage co-registration.ConclusionThe proposed two-stage registration method significantly improved the co-registration between PET and LGE in integrated PET/MR imaging. The technique may improve diagnostic accuracy of non-ischemic cardiomyopathies via better image co-registration.Registered No.DF-2020-085, 2020.04.30

Molecular Imaging Using Cardiac PET/CT: Opportunities to Harmonize Diagnosis and Therapy

Purpose of Review Current therapeutic strategies to mitigate heart failure progression after myocardial infarction involve support of endogenous repair through molecular targets. The capacity for repair varies greatly between individuals. In this review, we will assess how cardiac PET/CT enables precise characterization of early pathogenetic processes which govern ventricle remodeling and progression to heart failure. Recent Findings Inflammation in the first days after myocardial infarction predicts subsequent functional decline and can influence therapy decisions. The expansion of anti-inflammatory approaches to improve outcomes after myocardial infarction may benefit from noninvasive characterization using imaging. Novel probes also allow visualization of fibroblast transdifferentiation and activation, as a precursor to ventricle remodeling. Summary The expanding arsenal of molecular imaging agents in parallel with new treatment options provides opportunity to harmonize diagnostic imaging with precision therapy.