Same-day repeatability and Between-Sequence reproducibility of Mean ADC in PI-RADS lesions

• Published in: European journal of radiology Vol. 165; p. 110898
• Main Authors: Zhang, Kevin Sun, Neelsen, Christian Jan Oliver, Wennmann, Markus, Glemser, Philipp Alexander, Hielscher, Thomas, Weru, Vivienn, Görtz, Magdalena, Schütz, Viktoria, Stenzinger, Albrecht, Hohenfellner, Markus, Schlemmer, Heinz-Peter, Bonekamp, David
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01.08.2023
• Subjects: ADC; Apparent diffusion coefficient; Prostate; Repeatability; Reproducibility; Retest; Stability; Test; ADC; Stability; rsEPI; CoV; RDC; Repeatability; LoAs; RC; Reproducibility; Test; PI-RADS; Retest; ssEPI; B&A plot; Prostate; Apparent diffusion coefficient
• DOI: 10.1016/j.ejrad.2023.110898
• ISSN: 0720-048X; 1872-7727

•ADC measurements in prostate lesions show notable variability.•For quantitative ADC assessment, 3D-ROIs are superior to 2D-ROIs.•The cut-off for measurement-based ADC variability is approx. 200 × 10-6 mm2/s (3D-ROIs)•Sequential ADC measurements are feasible by different raters or sequences.•Two DWI sequences demonstrate no significant bias and high comparability. This study aimed to assess repeatability after repositioning (inter-scan), intra-rater, inter-rater and inter-sequence variability of mean apparent diffusion coefficient (ADC) measurements in MRI-detected prostate lesions. Forty-three patients with suspicion for prostate cancer were included and received a clinical prostate bi-/multiparametric MRI examination with repeat scans of the T2-weighted and two DWI-weighted sequences (ssEPI and rsEPI). Two raters (R1 and R2) performed single-slice, 2D regions of interest (2D-ROIs) and 3D-segmentation-ROIs (3D-ROIs). Mean bias, corresponding limits of agreement (LoA), mean absolute difference, within-subject coefficient of variation (CoV) and repeatability/reproducibility coefficient (RC/RDC) were calculated. Bradley & Blackwood test was used for variance comparison. Linear mixed models (LMM) were used to account for multiple lesions per patient. Inter-scan repeatability, intra-rater and inter-sequence reproducibility analysis of ADC showed no significant bias. 3D-ROIs demonstrated significantly less variability than 2D-ROIs (p < 0.01). Inter-rater comparison demonstrated small significant systematic bias of 57 × 10-6 mm2/s for 3D-ROIs (p < 0.001). Intra-rater RC, with the lowest variation, was 145 and 189 × 10-6 mm2/s for 3D- and 2D-ROIs, respectively. For 3D-ROIs of ssEPI, RCs and RDCs were 190–198 × 10-6 mm2/s for inter-scan, inter-rater and inter-sequence variation. No significant differences were found for inter-scan, inter-rater and inter-sequence variability. In a single-scanner setting, single-slice ADC measurements showed considerable variation, which may be lowered using 3D-ROIs. For 3D-ROIs, we propose a cut-off of ∼ 200 × 10-6 mm2/s for differences introduced by repositioning, rater or sequence effects. The results suggest that follow-up measurements should be possible by different raters or sequences.