<p><strong>Prior to proceeding with PUL, clinicians should counsel patients with LUTS/BPH that this procedure involves implanting permanent tines that may impact future procedures and future imaging of the prostate. (<em>Expert Opinion</em>)</strong></p>
Discussion
Discussion
<p>The PUL implant/tines consists of a lateral nitinol capsular tab and a medial stainless-steel urethral end-piece joined together via a segment of non-absorbable PET suture. While the nitinol capsular tab and monofilament PET suture connecting both tabs are not easily visible on MRI, the stainless-steel urethral tab creates artifacts on MRI. Therefore, PUL has a magnetic resonance (MR) conditional label, and according to the manufacturer, patients can be safely scanned immediately after placement up to 3 T with a spatial field gradient of up to 1,500 G/cm (15 T/m), and a maximum MR system-specific absorption rate of 4 W/kg for 15 minutes of continuous scanning.<sup>345</sup></p>
<p>Benidir et al. is a single site, retrospective, 37-patient study that showed all patients had MRI artifacts created by the PUL tines. The transition zone (TZ) was more likely to be affected by poor image quality compared to the peripheral zone (15% versus 3%; P<0.001). The base and mid-regions were more affected than the apex (13% and 9% versus 5%, respectively; P<0.001). Diffusion-weighted images/apparent diffusion coefficient (DWI/ADC) were more affected than T2-weighted images (T2-WI) (27% versus 0.3%; P<0.001) and dynamic contrast-enhanced (DCE) images (27% versus 0%; P<0.001).<sup>352</sup></p>
<p>In this study, on average, only 6% of the prostate volume was obscured by the PUL artifact on T2-WI; however, the impact on DWI/ADC was 32% on average. As a result, readers in this study found that the images were of poor diagnostic quality (i.e., Prostate Image Quality [PI-QUAL] ≤2) in 16-24% of the exams versus 5% of the exams receiving similar scores in the landmark PRECISION trial, which showed superiority of MRI-targeted biopsy versus TRUS-guided biopsy for clinically significant prostate cancer detection. Therefore, this study concluded that it is likely that PUL-related susceptibility artifacts can hinder MRI lesion detection.<sup>352</sup></p>