PrecisionPro Fusion: Clinical Validation of an Automated MRI-CT Fusion System for Prostate Radiotherapy Planning

BackgroundAccurate image registration between magnetic resonance imaging (MRI) and computed tomography (CT) is required for precise radiation therapy of prostate cancer. Manual registration methods have been identified as a significant barrier to the implementation of advanced treatment techniques such as focal boost therapy. PurposeTo evaluate the accuracy of PrecisionPro Fusion--an automated MRI-CT registration pipeline-- compared to manual registration by experienced radiation oncologists. Materials and MethodsWe conducted a prospective, multi-institutional validation study involving six genitourinary radiation oncologists from three institutions who performed registrations on 20 patient cases. The study used a two-round design with a one-month washout period, where physicians conducted MRI-CT registrations with and without PrecisionPro Fusion. We compared PrecisionPro Fusion to practical accuracy limits of manual registration, defined by intra-physician variability (distance between a physicians two MRI-CT registrations of the same patient case) and inter-physician variability (maximum distance between a physicians registration and the physician consensus-- average of all physicians registrations of that patient case). Physician participants reported on the PrecisionPro Fusion user experience using a System Usability Scale questionnaire. ResultsIntra-physician variability for manual subspecialist registrations was median 2.9 mm (IQR: 1.9, 5.4); inter-physician variability was median: 4.7 mm (4.3, 5.7). PrecisionPro Fusion registrations had median distance from the physician consensus of 1.3 mm (IQR: 0.9, 2.7). The system received high usability scores (median 81; IQR: 74, 88). ConclusionPrecisionPro Fusion provides prostate MRI-CT registration accuracy comparable to manual physician registration. Automated MRI-CT registration could enable faster delineation of structures visible on MRI, including the urethra and intraprostatic tumors.