Faculty Bibliography

OBJECTIVE: The purpose of this study was to compare the reproducibility and diagnostic performance of 2D and 3D ROIs for prostate apparent diffusion coefficient (ADC) measurements. MATERIALS AND METHODS: The study included 56 patients with prostate cancer undergoing 3-T MRI including DWI (b = 50 and 1000 s/mm2) before radical prostatectomy. Histologic findings from prostatectomy specimens were reviewed to denote each patient's dominant tumor and a benign region with visually decreased ADC. Three readers independently measured the ADCs of both areas using an ROI placed on a single slice through the lesion (2D) and an ROI encompassing all slices through the lesion (3D). Readers repeated measurements after 3 weeks. Assessment included Bland-Altman analysis (coefficient of repeatability [CR] in which lower values indicated higher reliability) and ROC analysis. RESULTS: For intrareader variability, the CRs across readers for all ROIs were 9.9% for 2D and 9.3% for 3D. For tumor ROIs the CRs were 10.6% for 2D and 9.6% for 3D. For interreader variability, the CRs across readers for all ROIs were 17.1% for 2D and 20.5% for 3D and for tumor ROIs were 17.9% for 2D and 22.2% for 3D. For combined reader data, the AUCs for benign and malignant findings were 0.77 for 2D and 0.78 for 3D (p = 0.146). For differentiating Gleason score (GS) 3 + 3 from GS > 3 + 3 tumors, the AUCs were 0.92 for 2D and 0.92 for 3D ROIs (p = 0.649). For differentiating GS /= 4 + 3 tumors, the AUCs were 0.70 for 2D and 0.67 for 3D ROIs (p = 0.004). CONCLUSION: Use of a 3D ROI did not improve intrareader or interreader reproducibility or diagnostic performance compared with use of a 2D ROI for prostate ADC measurements. Interreader reproducibility of 2D ROIs was suboptimal nonetheless.

Purpose of Review: The widely acknowledged limitations of the standard prostate cancer (PCa) diagnostic paradigm have provided an impetus to explore novel imaging modalities to diagnose, localize, and risk stratify PCa. As the body of literature focused on HistoScanningTM(HS) grows, there is need for a comprehensive review of the clinical efficacy of this technology. Recent Findings: Eighteen original, English language articles were found to adequately study the use of HistoScanningTM for prostate cancer diagnosis in the clinical setting. The articles were found by conducting a bibliographic search of PubMed in April 2017 in addition to utilizing references. The studies are divided into four groups based on study design. Study methods and quantitative data are summarized for each of the relevant articles. The results are synthesized to evaluate the utility of HistoScanningTM for the purpose of diagnosing PCa. Summary: Despite the promise of early pilot studies, there is a lack of consistent results across a number of further investigations of HistoScanningTM. This becomes increasingly evident as study size increases. As various other modern diagnostic modalities continue to develop, the future of HistoScanningTM, both alone and in conjunction with these technologies, remains unclear.

RATIONALE AND OBJECTIVES: This study aimed to assess a novel method of three-dimensional (3D) co-registration of prostate magnetic resonance imaging (MRI) examinations performed before and after prostate cancer focal therapy. MATERIALS AND METHODS: We developed a software platform for automatic 3D deformable co-registration of prostate MRI at different time points and applied this method to 10 patients who underwent focal ablative therapy. MRI examinations were performed preoperatively, as well as 1 week and 6 months post treatment. Rigid registration served as reference for assessing co-registration accuracy and precision. RESULTS: Segmentation of preoperative and postoperative prostate revealed a significant postoperative volume decrease of the gland that averaged 6.49 cc (P = .017). Applying deformable transformation based on mutual information from 120 pairs of MRI slices, we refined by 2.9 mm (max. 6.25 mm) the alignment of the ablation zone, segmented from contrast-enhanced images on the 1-week postoperative examination, to the 6-month postoperative T2-weighted images. This represented a 500% improvement over the rigid approach (P = .001), corrected by volume. The dissimilarity by Dice index of the mapped ablation zone using deformable transformation vs rigid control was significantly (P = .04) higher at the ablation site than in the whole gland. CONCLUSIONS: Our findings illustrate our method's ability to correct for deformation at the ablation site. The preliminary analysis suggests that deformable transformation computed from mutual information of preoperative and follow-up MRI is accurate in co-registration of MRI examinations performed before and after focal therapy. The ability to localize the previously ablated tissue in 3D space may improve targeting for image-guided follow-up biopsy within focal therapy protocols.