Advanced Diffusion Magnetic reSonance Prostate Imaging for Reducing Extraneous Biopsies (ASPIRE) - Calibration Component (Multi-centre Scanner Calibration) and Validation Component (Multi-centre Validation)

Overview: ASPIRE constitutes three components:

• Scanner Set-up Component (optional), at all sites (except University College London Hospitals NHS Foundation Trust (UCLH)),
• Multi-centre Calibration Component and
• Multi-centre Diagnostic Accuracy Validation Component Scanner Set-up Component (optional): A multi-centre optional optimisation study conducted across multiple National Health Service (NHS) hospital sites, apart from UCLH, once the advanced MRI sequences (VERDICT, fast VERDICT, and RSI) have been installed or programmed on each scanner by a dedicated research engineering team. Sequence parameters (such as b-value distributions, diffusion times, and echo times) will be standardised as much as possible across platforms, recognising that some vendor-specific adjustments may be required. This component includes a very small, optional cohort of local volunteer patients who are already undergoing a planned, routine MRI scan. Scans in this component are planning to be used as a quality assurance measure once these advanced sequences are installed ahead of the calibration cohort.

This Optional Scanner Set Up Component is not powered to test a clinical hypothesis; instead, its endpoint is the successful implementation of protocols and generation of reliable imaging at each site. As a process measure, success will be declared if the advanced sequences are operational on all scanners with adequate image quality. Men will be referred to this component based on a clinical suspicion of prostate cancer. Patients can expect 1 standard MRI scan plus all additional study sequences. The standard MRI scan can be either a bi-parametric or multiparametric MRI scan depending on the availability of the site where the scan is being performed. Patients will complete this MRI and exit the study with no follow up planned for this component.

Multi-centre Calibration Component: A technical feasibility assessment study involving NHS hospital sites equipped with 3 Tesla MRI scanners from each major MRI vendor (Philips, Siemens, GE) with potential for additional sites to represent duplicates from vendors, covering platform variations. The participating site selection captures the vendor diversity likely to be encountered in a larger trial. At each site, the VERDICT, fast VERDICT, and RSI MRI sequences will be installed and tested. This component involves a small travelling volunteer cohort design of patients who will undergo the advanced diffusion research MRI scan on two different scanners within a short timeframe. By scanning the same individuals at different sites, within a small timeframe, we are enabling direct comparison of measurements and direct calibration of the quantitative parameters can be performed. This component seeks primarily to develop methods (proof-of-concept) and is not designed to evaluate clinical outcomes.

The primary data collected in the Calibration Component are the imaging metrics (e.g., VERDICT Fractional intracellular volume (fIC) values) from each scanner for each subject. These will be analysed to derive transformation formulas that map values from one scanner to an equivalent value on another, effectively creating a calibration curve for each scanner/vendor combination. This component will also record practical aspects such as the success rate of sequence deployment, any scanner-specific issues, and qualitative image quality assessments at each site.