Assesment of Multiparametric Magnetic Resonance Image Quality for Prostate Cancer Detection Using Pi-qual Scoring System at Kenyatta National Hospital & the Nairobi Hospital

Abstract

Background: Prostate Cancer is the most prevalent non-cutaneous neoplasm of males in Kenya with an age standardized rate of 40.6/100000. Multi parametric magnetic resonance imaging of the prostate (T2, DWI, DCE) is currently recommended in international guidelines as an indispensable tool for detection, risk stratification and image guided biopsy of clinically significant prostate cancer. To attain the best out of this validated tool within the patient management pathway, several standardizing measures have been published and implemented globally. The first being Prostate Imaging Reporting and Data System (PIRADS–2012/2015) for internationally standardized image acquisition and reporting then most recently Prostate Imaging Quality (PIQUAL) (2020) for evaluation of magnetic resonance image quality. PIQUAL is derived from the PIRADS guidelines and it in cooperates minimal technical parameter for acquisition and a visual assessment criterion used to evaluate MR image quality prior to interpretation. Adherence to the PIRADS guidelines have been shown to produce good diagnostic quality images and vice versa. Objective: Multi parametric magnetic resonance imaging of the prostate is currently used for prostate cancer management in Kenyatta National Hospital and The Nairobi Hospital. The purpose of this study was to evaluate the quality of multi parametric magnetic resonance prostate images, using PIQUAL criteria, of patients with clinical suspicion of Prostate Cancer. Methods and Materials: This Prospective cross-sectional study was conducted in Kenyatta National Hospital and Nairobi Hospital following approval by KNH/UON ERC and NH ERC during a 6-month period from January 2022–June 2022. Study subjects that met the inclusion criteria were 63 patients suspected to have prostate cancer, selected by simple random sampling. All images were acquired using 3 Tesla Phillips MRI scanner KNH (Phillips Ingenia 2018 model) and NH (Phillips Achieva 2013 model). The pelvic phased array coil was used in both study centres and none utilized an endorectal coil The MRI scans were evaluated and scored using the PI-QUAL scoring check list. The collected data was checked for completeness and free of error prior to entry into Excel 2017. Thereafter the data was exported to Statistical Package for social services version 26 for analysis. The adherence to PIQUAL criteria was summarized as frequencies and percentages for categorical data and as means. All statistical tests were considered significant where the p value <0.05.

Results: The lowest adherence to PIQUAL technical parameters in the T2W sequence was in-plane resolution frequency encoding ≤0.4mm KNH 0% NH 0%; Slice Gaps (0) KNH 38.5 %, NH 0 %. Only KNH n=8 (31%), NH n=0 (0%) T2W images evaluated were independently of diagnostic quality. In both study sites there was excellent 100% adherence in acquiring the DWI Axial planes that were synchronous with the T2W; Multiple b values (0,500,1000 s/mm²); High b values acquired 1600 s/mm²; DWI Slice thickness <4mm; DWI In-plane resolution frequency and Phase encoding <2., 2. 5mm.The commonest artefact degrading DWI image quality was magnetic field in-homogeneity at the air/tissue interface caused by a distended rectum. The lowest adherence to PIQUAL criteria in the DCE sequence was seen in Slice thickness(3mm) KNH (0%) mean 5.9 mm and the inter slice gap (0) KNH (0%) mean -3.0mm, NH (0%) mean 1.5 mm. Adherence to the PIQUAL criteria of minimal technical parameters was seen highest in the DWI sequence 89.5 %, followed by DCE 83.5 % and lowest seen in T2WI 68.3%. The overall PIQUAL score was average with majority of the scans scoring PIQUAL 3 n=53 (84%) which has a clinical implication in that it is possible to rule in all significant lesions but as the same time not possible to rule out all significant lesions. Conclusion: Optimal diagnostic image quality can be achieved by applying technical guidelines achieved documented from past and current research like the PIQUAL criteria which forms a basis for standardization of prostatic mpMR image quality. Continuous application, education and research around optimization of the multiparametric magnetic resonance prostate imaging is important and necessary as it is now recognized as the future of prostate cancer management. PIQUAL is the first of its kind but revisions, driven by research, may be required in its future.