Evaluation of an Automated Analysis Tool for Prostate Cancer Prediction Using Multiparametric Magnetic Resonance Imaging

Objective To evaluate the diagnostic performance of an automated analysis tool for the assessment of prostate cancer based on multiparametric magnetic resonance imaging (mpMRI) of the prostate. Methods A fully automated analysis tool was used for a retrospective analysis of mpMRI sets (T2-weighted, T1-weighted dynamic contrast-enhanced, and diffusion-weighted sequences). The software provided a malignancy prediction value for each image pixel, defined as Malignancy Attention Index (MAI) that can be depicted as a colour map overlay on the original images. The malignancy maps were compared to histopathology derived from a combination of MRI-targeted and systematic transperineal MRI/TRUS-fusion biopsies. Results In total, mpMRI data of 45 patients were evaluated. With a sensitivity of 85.7% (with 95% CI of 65.4-95.0), a specificity of 87.5%(with 95% CI of 69.0-95.7) and a diagnostic accuracy of 86.7% (with 95% CI of 73.8-93.8) for detection of prostate cancer, the automated analysis results corresponded well with the reported diagnostic accuracies by human readers based on the PI-RADS system in the current literature. Conclusion The study revealed comparable diagnostic accuracies for the detection of prostate cancer of a user-independent MAI-based automated analysis tool and PI-RADS-scoring-based human reader analysis of mpMRI. Thus, the analysis tool could serve as a detection support system for less experienced readers. The results of the study also suggest the potential of MAI-based analysis for advanced lesion assessments, such as cancer extent and staging prediction

Examples of MAI profiles.

<p>Confirmed Gleason score 7a (3+4, left) and Gleason score 8 (4+4, right) lesions.</p

Overview of MAI algorithm steps.

<p>Overview of MAI algorithm steps.</p

Comparison of computed MAI diagnostic accuracy with that of human readers based on PI-RADS scoring.

<p>Comparison of computed MAI diagnostic accuracy with that of human readers based on PI-RADS scoring.</p

Sensitivity, specificity and Youden index of MAI-based prostate cancer detection at different mean MAI threshold values.

<p>Sensitivity, specificity and Youden index of MAI-based prostate cancer detection at different mean MAI threshold values.</p

ROC plot of MAI diagnostic accuracy.

<p>ROC plot of MAI diagnostic accuracy.</p

Parameter settings of deployed multiparametric MRI sequences.

<p>Parameter settings of deployed multiparametric MRI sequences.</p

Example of a MAI map on a T2W image overlay.

<p>Example of a MAI map on a T2W image overlay.</p

Magnetic Resonance Imaging-Guided Transurethral Ultrasound Ablation of Prostate Tissue in Patients with Localized Prostate Cancer: A Prospective Phase 1 Clinical Trial.

BACKGROUND: Magnetic resonance imaging-guided transurethral ultrasound ablation (MRI-TULSA) is a novel minimally invasive technology for ablating prostate tissue, potentially offering good disease control of localized cancer and low morbidity. OBJECTIVE: To determine the clinical safety and feasibility of MRI-TULSA for whole-gland prostate ablation in a primary treatment setting of localized prostate cancer (PCa). DESIGN, SETTING, AND PARTICIPANTS: A single-arm prospective phase 1 study was performed at three tertiary referral centers in Canada, Germany, and the United States. Thirty patients (median age: 69 yr; interquartile range [IQR]: 67-71 yr) with biopsy-proven low-risk (80%) and intermediate-risk (20%) PCa were treated and followed for 12 mo. INTERVENTION: MRI-TULSA treatment was delivered with the therapeutic intent of conservative whole-gland ablation including 3-mm safety margins and 10% residual viable prostate expected around the capsule. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Primary end points were safety (adverse events) and feasibility (technical accuracy and precision of conformal thermal ablation). Exploratory outcomes included quality of life, prostate-specific antigen (PSA), and biopsy at 12 mo. RESULTS AND LIMITATIONS: Median treatment time was 36min (IQR: 26-44) and prostate volume was 44ml (IQR: 38-48). Spatial control of thermal ablation was ±1.3mm on MRI thermometry. Common Terminology Criteria for Adverse Events included hematuria (43% grade [G] 1; 6.7% G2), urinary tract infections (33% G2), acute urinary retention (10% G1; 17% G2), and epididymitis (3.3% G3). There were no rectal injuries. Median pretreatment International Prostate Symptom Score 8 (IQR: 5-13) returned to 6 (IQR: 4-10) at 3 mo (mean change: -2; 95% confidence interval [CI], -4 to 1). Median pretreatment International Index of Erectile Function 13 (IQR: 6-28) recovered to 13 (IQR: 5-25) at 12 mo (mean change: -1; 95% CI, -5 to 3). Median PSA decreased 87% at 1 mo and was stable at 0.8 ng/ml (IQR: 0.6-1.1) to 12 mo. Positive biopsies showed 61% reduction in total cancer length, clinically significant disease in 9 of 29 patients (31%; 95% CI, 15-51), and any disease in 16 of 29 patients (55%; 95% CI, 36-74). CONCLUSIONS: MRI-TULSA was feasible, safe, and technically precise for whole-gland prostate ablation in patients with localized PCa. Phase 1 data are sufficiently compelling to study MRI-TULSA further in a larger prospective trial with reduced safety margins. PATIENT SUMMARY: We used magnetic resonance imaging-guided transurethral ultrasound to heat and ablate the prostate in men with prostate cancer. We showed that the treatment can be targeted within a narrow range (1mm) and has a well-tolerated side effect profile. A larger study is under way. TRIAL REGISTRATION: NCT01686958, DRKS00005311