Cardiovascular magnetic resonance imaging feature tracking: Impact of training on observer performance and reproducibility

Abstract

BackgroundCardiovascular magnetic resonance feature tracking (CMR-FT) is increasingly used for myocardial deformation assessment including ventricular strain, showing prognostic value beyond established risk markers if used in experienced centres. Little is known about the impact of appropriate training on CMR-FT performance. Consequently, this study aimed to evaluate the impact of training on observer variance using different commercially available CMR-FT software.MethodsIntra- and inter-observer reproducibility was assessed prior to and after dedicated one-hour observer training. Employed FT software included 3 different commercially available platforms (TomTec, Medis, Circle). Left (LV) and right (RV) ventricular global longitudinal as well as LV circumferential and radial strains (GLS, GCS and GRS) were studied in 12 heart failure patients and 12 healthy volunteers.ResultsTraining improved intra- and inter-observer reproducibility. GCS and LV GLS showed the highest reproducibility before (ICC >0.86 and >0.81) and after training (ICC >0.91 and >0.92). RV GLS and GRS were more susceptible to tracking inaccuracies and reproducibility was lower. Inter-observer reproducibility was lower than intra-observer reproducibility prior to training with more pronounced improvements after training. Before training, LV strain reproducibility was lower in healthy volunteers as compared to patients with no differences after training. Whilst LV strain reproducibility was sufficient within individual software solutions inter-software comparisons revealed considerable software related variance.ConclusionObserver experience is an important source of variance in CMR-FT derived strain assessment. Dedicated observer training significantly improves reproducibility with most profound benefits in states of high myocardial contractility and potential to facilitate widespread clinical implementation due to optimized robustness and diagnostic performance.

Comparison of feature tracking, fast‐SENC, and myocardial tagging for global and segmental left ventricular strain

“…Since reproducibility of the global measurements in our study closely matches that of an experienced observer from the aforementioned study, the results of our segmental comparison are indicative of a best‐case scenario. Furthermore, a recent study by Backhaus et al assessed the impact of observer training on reproducibility of FT strain measurements from three different vendors and found that the positive impact of observer experience is present independently of vendor choice …”

Head‐to‐head comparison of cardiovascular MR feature tracking cine versus acquisition‐based deformation strain imaging using myocardial tagging and strain encoding

“…Patient characteristics and ventricular volumetric data from the patient collection have been previously published. 18 All volunteers and patients gave written, informed consent before enrollment. The study was approved by the Ethics Committee of the Charité-University Medicine Berlin and complied with the Declaration of Helsinki.…”

“…Although all CMR-FT postprocessing software solutions are based on the same principles of optical flow, 12 vendorspecific properties remain undisclosed, resulting in limited understanding of intervendor variability. 16,18 This is often cited as the main reason why clinical routine implementation is lagging. Training and standardisation may overcome the bias introduced by inconsistent software application and will probably lead to reduced observer-induced variability.…”

“…Training and standardisation may overcome the bias introduced by inconsistent software application and will probably lead to reduced observer-induced variability. 18,36 Despite high consistency and correlation among vendors, differences in absolute agreement and absolute strain values suggest a requirement for software-specific reference values and furthermore a need for further standardisation to allow easy clinical routine implementation. Beyond limited agreement within FT-derived deformation assessment, the current data demonstrate distinct deviations for different approaches applied to evaluate myocardial deformation.…”

“…Although CMR FT has been validated extensively, [13][14][15][16][17] significant concerns regarding intervendor agreement remain, leading to slow clinical implementation. 18 Furthermore, agreement with the reference standard for CMR-derived deformation assessment CMR tagging has been inconclusive, 19,20 with considerable dependence on observer experience. 21 Recently, fSENC emerged as a faster alternative approach.…”