PI-QUAL version 2: an update of a standardised scoring system for the assessment of image quality of prostate MRI

Abstract

Multiparametric MRI is the optimal primary investigation when prostate cancer is suspected, and its ability to rule in and rule out clinically significant disease relies on high-quality anatomical and functional images. Avenues for achieving consistent high-quality acquisitions include meticulous patient preparation, scanner setup, optimised pulse sequences, personnel training, and artificial intelligence systems. The impact of these interventions on the final images needs to be quantified. The prostate imaging quality (PI-QUAL) scoring system was the first standardised quantification method that demonstrated the potential for clinical benefit by relating image quality to cancer detection ability by MRI. We present the updated version of PI-QUAL (PI-QUAL v2) which applies to prostate MRI performed with or without intravenous contrast medium using a simplified 3-point scale focused on critical technical and qualitative image parameters. CLINICAL RELEVANCE STATEMENT: High image quality is crucial for prostate MRI, and the updated version of the PI-QUAL score (PI-QUAL v2) aims to address the limitations of version 1. It is now applicable to both multiparametric MRI and MRI without intravenous contrast medium. KEY POINTS: High-quality images are essential for prostate cancer diagnosis and management using MRI. PI-QUAL v2 simplifies image assessment and expands its applicability to prostate MRI without contrast medium. PI-QUAL v2 focuses on critical technical and qualitative image parameters and emphasises T2-WI and DWI.

Keywords: Magnetic resonance imaging; Prostatic neoplasms; Quality control.

Fig. 1

PI-QUAL v2 scoring sheet that includes the basic mandatory PI-RADS v2.1 technical prerequisites for T2-WI, DWI and DCE, and the table to derive the PI-QUAL v2 score

Fig. 2

The four T2-WI criteria: examples with degraded axial (A, C, and E), coronal (G) and sagittal (H) T2-WI. Axial T2-WI of optimal image quality (B, D, and F). Axial T2-weighted images are from the same patients (before and after correction)

Fig. 3

The four DWI criteria: examples with degraded (A, C, E, F, H and I) and optimal (B, D, and G—this latter is axial T2-WI) image quality. Significant susceptibility artefacts can cause displacement/distortion, which is regarded as severe when the displacement is > 5 mm versus axial T2-WI (G) at the posterior surface of the prostate (H–I)

Fig. 4

The two DCE criteria: examples with degraded (A) and optimal (B) image quality