ABC | Volume 110, Nº3, March 2018

Review Article Ket et al Practical Implications of Myocardial Viability Studies Arq Bras Cardiol. 2018; 110(3):278-288 PET-RM A new technique – PET-MR started to be studied, but still has limited availability. The method has the advantage of combining the high spatial resolution ofMRwith the sensitivity of PET, without excessive ionizing radiation. In contrast to PET-CT, however, the synergism between PET and MR still need to be evaluated. Comparison of left ventricular end-diastolic wall thickness on MRI with glucose use on 18 F-FDG PET demonstrated that regions with an end-diastolic wall thickness of less than 5.5 mm had reduced glucose use, whereas regions with a wall thickness of 5.5 mm did not use this carbohydrate. 51 Studies on usefulness of PET-MR in cardiology are still ongoing, but it includes specific localization of lesions, contributing to therapeutic intervention. 52 Preliminary data indicate the possibility of PET-MR to measure inflammatory response to myocardial infarction and neoangiogenesis. 52,53 While MR is helpful in the analysis of scar extension, PET provides characteristics of the subepicardium and likelihood of functional recovery of areas free of scars. 51 Figure 5 – Patterns of transmurality of infarction in the presence and absence of viability by cardiac magnetic resonance Transmurality of infarction by cardiac magnetic resonance With infarction Preserved viability 1 – 25% Preserved viability 26 – 50% Preserved viability 51 – 75% Absence of viability > 75% Absence of viability Without infarction 1 – 25% 26 – 50% 51 – 75% > 75% Normal muscle Myocardial infarction 283