Native T1 and T2 mapping reference values in a South African population: Scanner-specific calibration on a 1.5 Tesla Siemens Aera system at Tygerberg Hospital

Abstract

Background: Quantitative myocardial T1 and T2 mapping is integral to cardiovascular magnetic resonance (CMR) imaging. Absolute myocardial relaxation times vary across imaging platforms due to system-specific technical factors. Consequently, mapping reference ranges are not transferable across platforms and require scanner-specific calibration. This study aimed to establish normal T1 and T2 reference intervals on a 1.5 Tesla (T) Siemens Aera system (Siemens, Erlangen, Germany) at Tygerberg Hospital. Methods: Healthy adults were prospectively enrolled using strict inclusion criteria. Participants were required to undergo a normal clinical evaluation before qualifying for CMR and potential study inclusion. Final inclusion followed confirmation of normal cardiac structure and function, with no late gadolinium enhancement (LGE) on CMR. CMR imaging included balanced steady-state free precession (SSFP) cine sequences, shortened modified Look-Locker inversion recovery (shMOLLI) T1 mapping, and T2-prepared mapping sequences with a balanced SSFP readout. Analysis was performed using cvi42 software (Circle Cardiovascular Imaging, Canada) with manual contouring, and reference ranges were derived as mean ± 2 standard deviations (SD). Results: A total of 76 participants met the inclusion criteria. Mean global native T1 was 998 ± 25.6 ms (reference interval 947–1 049 ms) and native T2 was 46.6 ± 1.8 ms (reference interval 43.0–50.1 ms). Conclusion: This study established scanner-specific native T1 and T2 reference intervals for a South African population scanned on a 1.5T Siemens Aera system.