Reference Ranges, Diagnostic and Prognostic Utility of Native T1 Mapping and Extracellular Volume for Cardiac Amyloidosis: A Meta-Analysis.

Background: Cardiac MRI is central to the evaluation of cardiac amyloidosis (CA). Native T mapping and extracellular volume (ECV) are novel MR techniques with evolving utility in cardiovascular diseases, including CA.

Purpose: To perform a meta-analysis of the diagnostic and prognostic data of native T mapping and ECV techniques for assessing CA.

Study Type: Systematic review and meta-analysis.

Population: In all, 3520 patients including 1539 with CA from 22 studies retrieved following systematic search of Pubmed, Cochrane, and Embase.

Field Strength/sequence: 1.5T or 3.0T/modified Look-Locker inversion recovery (MOLLI) or shortened MOLLI (shMOLLI) sequences.

Assessment: Meta-analysis was performed for all CA and for light-chain (AL) and transthyretin (ATTR) subtypes. Thresholds were calculated to classify native T and ECV values as not suggestive, indeterminate, or suggestive of CA.

Statistical Analysis: Area under the receiver-operating characteristic curves (AUCs) and hazards ratios (HRs) with 95% confidence intervals (95% CI) were pooled using random-effects models and Open-Meta(Analyst) software.

Results: Six studies were diagnostic, 16 studies reported T and ECV values to determine reference range, and six were prognostic. Pooled AUCs (95% CI) for diagnosing CA were 0.92 (0.89-0.96) for native T mapping and 0.96 (0.93-1.00) for ECV, with similarly high detection rates for AL- and ATTR-CA. Based on the pooled values of native T and ECV in CA and control subjects, the thresholds that suggested the absence, indeterminate, or presence of CA were identified as <994 msec, 994-1073 msec, and >1073 msec, respectively, for native T at 1.5T. Pooled HRs (95% CI) for predicting all-cause mortality were 1.15 (1.08-1.22) for native T mapping as a continuous parameter, 1.19 (1.01-1.40) for ECV as a continuous parameter, and 4.93 (2.64-9.20) for ECV as a binary threshold.

Data Conclusion: Native T mapping and ECV had high diagnostic performance and predicted all-cause mortality in CA.

Level Of Evidence: 1 TECHNICAL EFFICACY STAGE: 2.