Invivo

Multi-parametric MRI of the prostate is performed on a 3-Tesla MR scanner (Achieva-TX, Philips Healthcare, Best, NL) using the anterior half of a 32-channel SENSE cardiac coil (In Vivo, Philips Healthcare, Gainesville FL, USA) and an endorectal coil (BPX-30, Medrad, Indianola PA, USA). No pre-examination bowel preparation was required. The balloon of each endorectal coil is distended with approximately 45 mL of perfluorocarbon (Fluorinert FC-770, 3M, St Paul, MN, USA) to reduce imaging artifacts related to air-induced susceptibility. T2-weighted (T2W) MRI and diffusion-weighted MRI (DWI) are acquired. T2W MRI has a resolution of 0.27mm × 0.27mm. The standard DWI is acquired with 5 evenly-spaced b-values (0–750 s/mm²), and a map of the apparent diffusion coefficient (ADC) is calculated per voxel. Multi-parametric MRI is independently evaluated by three experienced genitourinary radiologists (SS, BT, and PLC with 2, 7 and 14 years of experience). The whole prostate, peripheral zone, transition zone, and cancer lesions are delineated and recorded in an MRI coordinate system. The whole prostate is first automatedly segmented by research software (iCAD Inc., Nashua, NH, USA) and the resulting segmentation is manually adjusted by the radiologists. DWI images are rigidly registered with T2W MRI images using MR coordinate information [16 ]. The registration is performed per MR slice.

Multiparametric prostate MRIs were acquired with a 3T MRI scanner (Achieva 3 T-Tx, Philips Healthcare) using a 32-channel cardiac coil (Invivo, Philips Healthcare) without endorectal coil. MpMRIs included T1WI, three plane T2WI, DWI MRI with high b value (b1500) and ADC maps, DCE and post-contrast T1WI with fat suppression. Slice thickness and locations were kept constant for axial T2WI, DWI MRI and DCE images without gap. All parameters were compatible with the PI-RADSv2 minimum technical standards (Table 1). For bowel preparation, the Fleet’s™ enema was administered by the patients themselves approximately 12 h before mpMRI.