Reproducibility and Repeatability of Intervoxel Incoherent Motion MRI Acquisition Methods in Liver

Abstract

BackgroundIntravoxel incoherent motion (IVIM) diffusion weighted MRI (DWI) has potential for evaluating hepatic fibrosis but image acquisition technique influence on diffusion parameter estimation bears investigation.PurposeTo minimize variability and maximize repeatably in abdominal DWI in terms of IVIM parameter estimates.Study TypeProspective test–retest and image quality comparison.SubjectsHealthy volunteers (3F/7M, 29.9 ± 12.9 years) and Family Study subjects (18F/12M, 51.7 ± 16.7 years), without and with liver steatosis.Field Strength/SequenceAbdominal single‐shot echo‐planar imaging (EPI) and simultaneous multi‐slice (SMS) DWI sequences with respiratory triggering (RT), breath‐holding (BH), and navigator echo (NE) at 3 Tesla.AssessmentSMS‐BH, EPI‐NE, and SMS‐RT data from twice‐scanned healthy volunteers were analyzed using 6 × b‐values (0–800 s⋅mm−2) and lower (LO) and higher (HI) b‐value ranges. Family Study subjects were scanned using SMS and standard EPI sequences. The biexponential IVIM model was used to estimate fast‐diffusion coefficient (Df), fraction of fast diffusion (f), and slow‐diffusion coefficient (Ds). Scan time, estimated signal‐to‐noise ratio (eSNR), eSNR per acquisition, and distortion ratio were compared.Statistical TestsCoefficients of variation (CoV) and Bland Altman analyses were performed for test–retest repeatability. Interclass correlation coefficient (ICC) assessed interobserver agreement with P < 0.05 deemed significant.ResultsWithin‐subject CoVs among volunteers (N = 10) for f and Ds were lowest in EPI‐NE‐LO (11.6%) and SMS‐RT‐HI (11.1%). Inter‐observer ICCs for f and Ds were highest for EPI‐NE‐LO (0.63) and SMS‐RT‐LO (0.76). Df could not be estimated for most subjects. Estimated eSNR (EPI = 21.9, SMS = 4.7) and eSNR time (EPI = 6.7, SMS = 16.6) were greater for SMS, with less distortion in the liver region (DR‐PE: EPI = 23.6, SMS = 13.1).Data ConclusionSimultaneous multislice acquisitions had significantly less variability and higher ICCs of Ds, higher eSNR, less distortion, and reduced scan time compared to EPI.Evidence Level2Technical EfficacyStage 1