Localized low-grade prostate cancer is challenging to visualize in DW-MRI, and this imaging technique provides no additional prognostic benefit compared to PSA and repeat biopsies.

Background The aim of this study is to investigate the potential impact of prostate magnetic resonance imaging (MRI) -related interreader variability on a population-based randomized prostate cancer screening trial (ProScreen). Methods From January 2014 to January 2018, 100 men aged 50–63 years with clinical suspicion of prostate cancer (PCa) in Helsinki University Hospital underwent MRI. Nine radiologists individually reviewed the pseudonymized MRI scans of all 100 men in two ProScreen trial centers. All 100 men were biopsied according to a histological composite variable comprising radical prostatectomy histology (N = 38) or biopsy result within 1 year from the imaging (N = 62). Fleiss’ kappa (κ) was used to estimate the combined agreement between all individual radiologists. Sample data were subsequently extrapolated to 1000-men subgroups of the ProScreen cohort. Results Altogether 89% men of the 100-men sample were diagnosed with PCa within a median of 2.4 years of follow-up. Clinically significant PCa (csPCa) was identified in 76% men. For all PCa, mean sensitivity was 79% (SD ±10%, range 62–96%), and mean specificity 60% (SD ±22%, range 27–82%). For csPCa (Gleason Grade 2–5) MRI was equally sensitive (mean 82%, SD ±9%, range 67–97%) but less specific (mean 47%, SD ±20%, range 21–75%). Interreader agreement for any lesion was fair (κ 0.40) and for PI-RADS 4–5 lesions it was moderate (κ 0.60). Upon extrapolating these data, the average sensitivity and specificity to a screening positive subgroup of 1000 men from ProScreen with a 30% prevalence of csPCa, 639 would be biopsied. Of these, 244 men would be true positive, and 395 false positive. Moreover, 361 men would not be referred to biopsy and among these, 56 csPCas would be missed. The variation among the radiologists was broad as the least sensitive radiologist would have twice as many men biopsied and almost three times more men would undergo unnecessary biopsies. Although the most sensitive radiologist would miss only 2.6% of csPCa (false negatives), the least sensitive radiologist would miss every third. Conclusions Interreader agreement was fair to moderate. The role of MRI in the ongoing ProScreen trial is crucial and has a substantial impact on the screening process.

Aims: The present study compares preoperative magnetic resonance enterography (MRE) accuracy in diagnosing stenoses, abscesses and fistulas to intraoperative findings in Crohn's disease patients, and determines whether discordance between these methods alter surgical plans. Methods: Our study included 55 consecutive patients scheduled for elective surgery due to Crohn's disease in a single institution between January 2011 and May 2015, whose surgical findings were also compared to preoperative MREs. Data were retrospectively analyzed. Results: Among these 55 patients, we found 80 stenoses, 5 abscesses and 18 fistulas during surgery. The MRE sensitivity, specificity and accuracy, respectively, reached 100, 77.8 and 96.4% for stenoses; 80.0, 90.0 and 89.1% for abscesses; and 77.8, 83.8 and 81.8% for fistulas. The operative plan was modified for 7 patients (12.7%) due to erroneous MRE diagnoses. No patient needed conversion or an unplanned stoma placement due to an incorrect diagnosis using MRE. The MRE diagnosis did not agree with the surgical findings for 36 lesions, 16 of which resulted from adhesions that explained the incorrect MRE diagnoses. Conclusions: Hence, while MRE is a useful diagnostic tool preoperatively in Crohn's disease patients, the presence of intra-abdominal adhesions may cause erroneous diagnosis through MRE.

Multivisceral resection offers a 5-year survival of over 50% and local control of advanced rectal cancer in nearly 90% of carefully selected patients.