Normal values for native T1 at 1.5T in the pericardial fluid of healthy volunteers

Background T1 mapping cardiovascular magnetic resonance (CMR) imaging has been used to characterize pericardial effusions. The aim of this study was to measure pericardial fluid native T1 values in healthy volunteers to establish normal values. Methods Prospectively recruited volunteers (n=30) underwent CMR at 1.5T and native T1 maps were acquired using a MOLLI 5s(3s)3s acquisition scheme. A volume of pericardial fluid was imaged in a short-axis slice and in a slice perpendicular to the short-axis orientation. A reliable measurement had a region of interest size >10 mm 2 , coefficient of variation <10 %, and a relative difference <5 % between the two slice orientations. Results In 26/30 (87%) of volunteers, there was a sufficient amount of pericardial fluid to enable reliable measurement. Native T1 of pericardial fluid was 3262±163 (95% normal limits 2943–3581ms), and did not differ in the perpendicular slice orientation (3267±173 ms, p=0.75), due to sex (female 3311±177 vs. male 3220±142 ms, p=0.17), or age (R 2 =0.07, p=0.2) Conclusions This study shows that T1 values can be reliably measured in the pericardial fluid of healthy volunteers. It is the first to report normal reference ranges for T1 values at 1.5T in the pericardial fluid of healthy volunteers.