Abdominal Diffusion‐Weighted MRI With Simultaneous Multi‐Slice Acquisition: Agreement and Reproducibility of Apparent Diffusion Coefficients Measurements

Abstract

BackgroundSimultaneous multi‐slice diffusion‐weighted imaging (SMS‐DWI) can shorten acquisition time in abdominal imaging.PurposeTo investigate the agreement and reproducibility of apparent diffusion coefficient (ADC) from abdominal SMS‐DWI acquired with different vendors and different breathing schemes.Study TypeProspective.SubjectsTwenty volunteers and 10 patients.Field Strength/Sequence3.0 T, SMS‐DWI with a diffusion‐weighted echo‐planar imaging sequence.AssessmentSMS‐DWI was acquired using breath‐hold and free‐breathing techniques in scanners from two vendors, yielding four scans in each participant. Average ADC values were measured in the liver, pancreas, spleen, and both kidneys. Non‐normalized ADC and ADCs normalized to the spleen were compared between vendors and breathing schemes.Statistical TestsPaired t‐test or Wilcoxon signed rank test; intraclass correlation coefficient (ICC); Bland–Altman method; coefficient of variation (CV) analysis; significance level: P < 0.05.ResultsNon‐normalized ADCs from the four SMS‐DWI scans did not differ significantly in the spleen (P = 0.262, 0.330, 0.166, 0.122), right kidney (P = 0.167, 0.538, 0.957, 0.086), and left kidney (P = 0.182, 0.281, 0.504, 0.405), but there were significant differences in the liver and pancreas. For normalized ADCs, there were no significant differences in the liver (P = 0.315, 0.915, 0.198, 0.799), spleen (P = 0.815, 0.689, 0.347, 0.423), pancreas (P = 0.165, 0.336, 0.304, 0.584), right kidney (P = 0.165, 0.336, 0.304, 0.584), and left kidney (P = 0.496, 0.304, 0.443, 0.371). Inter‐reader agreements of non‐normalized ADCs were good to excellent (ICCs ranged from 0.861 to 0.983), and agreement and reproducibility were good to excellent depending on anatomic location (CVs ranged from 3.55% to 13.98%). Overall CVs for abdominal ADCs from the four scans were 6.25%, 7.62%, 7.08, and 7.60%.Data ConclusionThe normalized ADCs from abdominal SMS‐DWI may be comparable between different vendors and breathing schemes, showing good agreement and reproducibility. ADC changes above approximately 8% may potentially be considered as a reliable quantitative biomarker to assess disease or treatment‐related changes.Level of Evidence2Technical EfficacyStage 2