Native T1 mapping: inter-study, inter-observer and inter-center reproducibility in hemodialysis patients

Abstract

BackgroundNative T1 mapping is a cardiovascular magnetic resonance (CMR) technique that associates with markers of fibrosis and strain in hemodialysis patients. The reproducibility of T1 mapping in hemodialysis patients, prone to changes in fluid status, is unknown. Accurate quantification of myocardial fibrosis in this population has prognostic potential.MethodsUsing 3 Tesla CMR, we report the results of 1) the inter-study, inter-observer and intra-observer reproducibility of native T1 mapping in 10 hemodialysis patients; 2) inter-study reproducibility of left ventricular (LV) structure and function in 10 hemodialysis patients; 3) the agreement of native T1 map and native T1 phantom analyses between two centres in 20 hemodialysis patients; 4) the effect of changes in markers of fluid status on native T1 values in 10 hemodialysis patients.ResultsInter-study, inter-observer and intra-observer variability of native T1 mapping were excellent with co-efficients of variation (CoV) of 0.7, 0.3 and 0.4% respectively. Inter-study CoV for LV structure and function were: LV mass = 1%; ejection fraction = 1.1%; LV end-diastolic volume = 5.2%; LV end-systolic volume = 5.6%. Inter-centre variability of analysis techniques were excellent with CoV for basal and mid-native T1 slices between 0.8–1.2%. Phantom analyses showed comparable native T1 times between centres, despite different scanners and acquisition sequences (centre 1: 1192.7 ± 7.5 ms, centre 2: 1205.5 ± 5 ms). For the 10 patients who underwent inter-study testing, change in body weight (Δweight) between scans correlated with change in LV end-diastolic volume (ΔLVEDV) (r = 0.682;P = 0.03) representing altered fluid status between scans. There were no correlations between change in native T1 between scans (ΔT1) and ΔLVEDV or Δweight (P > 0.6). Linear regression confirmed ΔT1 was unaffected by ΔLVEDV or Δweight (P > 0.59).ConclusionsMyocardial native T1 is reproducible in HD patients and unaffected by changes in fluid status at the levels we observed. Native T1 mapping is a potential imaging biomarker for myocardial fibrosis in patients with end-stage renal disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s12968-017-0337-7) contains supplementary material, which is available to authorized users.

Reference range determination for imaging biomarkers: Myocardial T1

“…Reproducibility data on myocardial T 1 measurement is accumulating in the literature, including: assessment in Fabry disease; interstudy, interobserver, and intercenter reproducibility in hemodialysis patients; at different field strengths; evaluation of different T 1 mapping methods . It is advised that regularly repeated phantom‐based quality control is performed to periodically confirm that the status and stability of the MR system have not changed significantly during the time between establishing a reference range and clinical scanning .…”

Quantification of left ventricular mass by echocardiography compared to cardiac magnet resonance imaging in hemodialysis patients

“…Consequently, a reliable and valid method to detect LVH is needed for both clinical and scienti c implications [5,6]. For the assessment of left ventricular mass (LVM), cardiac magnetic resonance imaging (CMR) has been established as the most accurate and reproducible method [7][8][9]. However, given its limited availability and high cost, CMR is not practical for clinical use in large-scale clinical studies.…”

Multi‐modality cardiac imaging in advanced chronic kidney disease

“…85 The same authors report the method is reproducible and unaffected by fluid variability between dialysis sessions. 89 Rutherford et al studied a very similar cohort consisting of 33 HD patients and 28 controls and showed that global, septal, and midseptal native T1 is significantly higher in HD patients. Also, native T1 correlates with LV mass, suggesting that as LVH progresses in severity, the underlying tissue abnormalities simultaneously develop.…”