Short‐Term Repeatability of in Vivo Cardiac Intravoxel Incoherent Motion Tensor Imaging in Healthy Human Volunteers

Abstract

Background Intravoxel incoherent motion (IVIM) tensor imaging is a promising technique for diagnosis and monitoring of cardiovascular diseases. Knowledge about measurement repeatability, however, remains limited. Purpose To evaluate short‐term repeatability of IVIM tensor imaging in normal in vivo human hearts. Study Type Prospective. Population Ten healthy subjects without history of heart diseases. Field Strength/Sequence Balanced steady‐state free‐precession cine sequence and single‐shot spin‐echo echo planar IVIM tensor imaging sequence (9 b‐values, 0–400 seconds/mm2 and six diffusion‐encoding directions) at 3.0 T. Assessment Subjects were scanned twice with an interval of 15 minutes, leaving the scanner between studies. The signal‐to‐noise ratio (SNR) was evaluated in anterior, lateral, septal, and inferior segments of the left ventricle wall. Fractional anisotropy (FA), mean diffusivity (MD), mean fraction (MF), and helix angle (HA) in the four segments were independently measured by five radiologists. Statistical Tests IVIM tensor indexes were compared between observers using a one‐way analysis of variance or between scans using a paired t‐test (normal data) or a Wilcoxon rank‐sum test (non‐normal data). Interobserver agreement and test–retest repeatability were assessed using the intraclass correlation coefficient (ICC), within‐subject coefficient of variation (WCV), and Bland–Altman limits of agreements. Results SNR of inferior segment was significantly lower than the other three segments, and inferior segment was therefore excluded from repeatability analysis. Interobserver repeatability was excellent for all IVIM tensor indexes (ICC: 0.886–0.972; WCV: 0.62%–4.22%). Test–retest repeatability was excellent for MD of the self‐diffusion tensor (D) and MF of the perfusion fraction tensor (fp) (ICC: 0.803–0.888; WCV: 1.42%–9.51%) and moderate for FA and MD of the pseudo‐diffusion tensor (D*) (ICC: 0.487–0.532; WCV: 6.98%–10.89%). FA of D and fp and HA of D presented good test–retest repeatability (ICC: 0.732–0.788; WCV: 3.28%–8.71%). Data Conclusion The D and fp indexes exhibited satisfactory repeatability, but further efforts were needed to improve repeatability of D* indexes. Level of Evidence 2 Technical Efficacy Stage 1

Test-retest repeatability of intravoxel incoherent motion (IVIM) measurements in the cervical cord

“…However, the current cohort size is comparable to previous IVIM reliability studies [51][52][53][54] .…”

“…Furthermore, our results in the cervical cord show high repeatability compared to previous studies on IVIM reliability which used different acquisition protocols and fitting approaches in different organs 46,50–53 . A previous study applying IVIM in head and neck tissues reported CVs of F and D* varying between 15.27% and 22.14 %, and 29.24% and 41.80%, respectively 51 .…”

Comparison of Dynamic Contrast‐Enhanced MRI and Non‐Mono‐Exponential Model‐Based Diffusion‐Weighted Imaging for the Prediction of Prognostic Biomarkers and Molecular Subtypes of Breast Cancer Based on Radiomics

“…The NME models mainly include the intravoxel incoherent motion (IVIM), diffusion kurtosis and stretched exponential models [16][17][18] . The parameters derived from these models can reflect tumor microstructure, spatial heterogeneity and microvascular perfusion 19,20 . In the literature, these model parameters have been demonstrated to be the potential indicators for the prediction of receptor statuses and proliferation rates [21][22][23] .…”

“…[15][16][17] The parameters derived from these models can reflect tumor microstructure, spatial heterogeneity, and microvascular perfusion. 18,19 In the literature, these model parameters have been demonstrated to be the potential indicators for the prediction of receptor statuses and proliferation rates. 12,20,21 To date, however, the radiomic analysis of NME-DWI for determining the prognostic biomarkers and molecular subtypes of breast cancer still needs to be explored further.…”