Cardiovascular magnetic resonance (CMR) enables assessment and quantification of morphological and functional parameters of the heart, including chamber size and function, diameters of the aorta... Show moreCardiovascular magnetic resonance (CMR) enables assessment and quantification of morphological and functional parameters of the heart, including chamber size and function, diameters of the aorta and pulmonary arteries, flow and myocardial relaxation times. Knowledge of reference ranges ("normal values") for quantitative CMR is crucial to interpretation of results and to distinguish normal from disease. Compared to the previous version of this review published in 2015, we present updated and expanded reference values for morphological and functional CMR parameters of the cardiovascular system based on the peer-reviewed literature and current CMR techniques. Further, databases and references for deep learning methods are included. Show less
Background The T-1 Mapping and Extracellular volume (ECV) Standardization (T1MES) program explored T-1 mapping quality assurance using a purpose-developed phantom with Food and Drug Administration ... Show moreBackground The T-1 Mapping and Extracellular volume (ECV) Standardization (T1MES) program explored T-1 mapping quality assurance using a purpose-developed phantom with Food and Drug Administration (FDA) and Conformite Europeenne (CE) regulatory clearance. We report T-1 measurement repeatability across centers describing sequence, magnet, and vendor performance. Methods Phantoms batch-manufactured in August 2015 underwent 2 years of structural imaging, B-0 and B-1, and "reference" slow T-1 testing. Temperature dependency was evaluated by the United States National Institute of Standards and Technology and by the German Physikalisch-Technische Bundesanstalt. Center-specific T-1 mapping repeatability (maximum one scan per week to minimum one per quarter year) was assessed over mean 358 (maximum 1161) days on 34 1.5 T and 22 3 T magnets using multiple T-1 mapping sequences. Image and temperature data were analyzed semi-automatically. Repeatability of serial T-1 was evaluated in terms of coefficient of variation (CoV), and linear mixed models were constructed to study the interplay of some of the known sources of T-1 variation. Results Over 2 years, phantom gel integrity remained intact (no rips/tears), B-0 and B-1 homogenous, and "reference" T-1 stable compared to baseline (% change at 1.5 T, 1.95 +/- 1.39%; 3 T, 2.22 +/- 1.44%). Per degrees Celsius, 1.5 T, T-1 (MOLLI 5s(3s)3s) increased by 11.4 ms in long native blood tubes and decreased by 1.2 ms in short post-contrast myocardium tubes. Agreement of estimated T-1 times with "reference" T-1 was similar across Siemens and Philips CMR systems at both field strengths (adjusted R-2 ranges for both field strengths, 0.99-1.00). Over 1 year, many 1.5 T and 3 T sequences/magnets were repeatable with mean CoVs < 1 and 2% respectively. Repeatability was narrower for 1.5 T over 3 T. Within T1MES repeatability for native T-1 was narrow for several sequences, for example, at 1.5 T, Siemens MOLLI 5s(3s)3s prototype number 448B (mean CoV = 0.27%) and Philips modified Look-Locker inversion recovery (MOLLI) 3s(3s)5s (CoV 0.54%), and at 3 T, Philips MOLLI 3b(3s)5b (CoV 0.33%) and Siemens shortened MOLLI (ShMOLLI) prototype 780C (CoV 0.69%). After adjusting for temperature and field strength, it was found that the T-1 mapping sequence and scanner software version (both P < 0.001 at 1.5 T and 3 T), and to a lesser extent the scanner model (P = 0.011, 1.5 T only), had the greatest influence on T-1 across multiple centers. Conclusion The T1MES CE/FDA approved phantom is a robust quality assurance device. In a multi-center setting, T-1 mapping had performance differences between field strengths, sequences, scanner software versions, and manufacturers. However, several specific combinations of field strength, sequence, and scanner are highly repeatable, and thus, have potential to provide standardized assessment of T-1 times for clinical use, although temperature correction is required for native T-1 tubes at least. Show less
