Histological validation of prostate tissue composition measurement using hybrid multi-dimensional MRI: agreement with pathologists' measures.

PURPOSE: To validate prostate tissue composition measured using hybrid multi-dimensional MRI (HM-MRI) by comparing with reference standard (ground truth) results from pathologists' interpretation of clinical histopathology slides following whole mount prostatectomy. MATERIALS AND METHODS: 36 prospective participants with biopsy-confirmed prostate cancer underwent 3 T MRI prior to radical prostatectomy. Axial HM-MRI was acquired with all combinations of echo times of 57, 70, 150, 200 ms and b-values of 0, 150, 750, 1500 s/mm2 and data were fitted using a 3-compartment signal model using custom software to generate volumes for each tissue component (stroma, epithelium, lumen). Three experienced genitourinary pathologists independently as well as in consensus reviewed each histology image and provide an estimate of percentage of epithelium and lumen for regions-of-interest corresponding to MRI (n = 165; 64 prostate cancers and 101 benign tissue). Agreement statistics using total deviation index (TDI0.9) was performed for tissue composition measured using HM-MRI and reference standard results from pathologists' consensus. RESULTS: Based on the initial results showing typical variation among pathologists TDI0.9 = 25%, we determined we will declare acceptable agreement if the 95% one-sided upper confident limit of TDI0.9 is less than 30%. The results of tissue composition measurement from HM-MRI compared to ground truth results from the consensus of 3 pathologists, reveal that ninety percent of absolute paired differences (TDI0.9) were within 18.8% and 22.4% in measuring epithelium and lumen, respectively. We are 95% confident that 90% of absolute paired differences were within 20.6% and 24.2% in measuring epithelium and lumen, respectively. These were less than our criterion of 30% and inter-pathologists' agreement (22.3% for epithelium and 24.2% for lumen) and therefore we accept the agreement performance of HM-MRI. The results revealed excellent area under the ROC curve for differentiating cancer from benign tissue based on epithelium (HM-MRI: 0.87, pathologists: 0.97) and lumen volume (HM-MRI: 0.85, pathologists: 0.77). CONCLUSION: The agreement in tissue composition measurement using hybrid multidimensional MRI and consensus of pathologists is on par with the inter-raters (pathologists) agreement.

Effects of technological interventions on the safety of a medication-use system.

PURPOSE: A study was conducted to assess the effects and outcomes of implementing new technology into the medication-use process. METHODS: A pharmacy computer system, automated dispensing cabinets, and point-of-care products were implemented. The hypotheses of the study were that system errors in each phase of the medication-use process would decrease with the implementation of each technological application and that workload measures, such as staffing and inventory levels, would increase. Using a scripted questionnaire, interviews of participating staff (registered nurses, licensed practical nurses, nursing-unit clerks, pharmacists, pharmacy technicians, physicians, and physician assistants) were conducted to determine their impressions of the safety of the medication-use system before and after the implementation of technology. All hospitalwide errors were reported monthly between November 2002 and July 2005 by the number of errors per 1000 patient days and were categorized by error type. The accuracy of the medication administration record was examined; the pharmacy dispensing process was evaluated for accuracy, timeliness, and system changes; the accuracy of medication administration was observed; and staffing changes were also evaluated. RESULTS: Because of the technology implementation, the accuracy of patient identification was introduced, process changes and technological design identified potential failure modes in the medication administration process, inventory increased, turn-around time to process medication doses in the pharmacy decreased, accuracy of medication administration increased, and the staffing of nurses and pharmacists increased. CONCLUSION: Implementation of new technology into the medication management system standardized the medication administration processes, decreased turnaround time for processing medication orders, and increased accuracy of medication administration to patients.