Reader accuracy and confidence in diagnosing diffuse lung disease on high-resolution computed tomography of the lungs: impact of sampling frequency.

BACKGROUND: The accuracy of the number of high-resolution computed tomography (HRCT) images necessary to diagnose diffuse lung disease (DLD) is not well established. PURPOSE: To evaluate the impact of HRCT sampling frequency on reader confidence and accuracy for diagnosing DLD. MATERIAL AND METHODS: HRCT images of 100 consecutive patients with proven DLD were reviewed. They were: 48 usual interstitial pneumonia, 22 sarcoidosis, six hypersensitivity pneumonitis, five each of desquamative interstitial pneumonitis, eosinophilic granulomatosis, and lymphangioleiomyomatosis, and nine others. Inspiratory images at 1-cm increments throughout the lungs and three specified levels formed complete and limited examinations. In random order, three experts (readers 1, 2, and 3) ranked their top three diagnoses and rated confidence for their top diagnosis, independently and blinded to clinical information. RESULTS: Using the complete versus limited examinations for correct first-choice diagnosis, accuracy for reader 1 (R1) was 81% versus 80%, respectively, for reader 2 (R2) 70% versus 70%, and for reader 3 (R3) 64% versus 59%. Reader accuracy within their top three choices for complete versus limited examinations was: R1 91% versus 91% of cases, respectively, R2 84% versus 83%, and R3 79% versus 72% of cases. No statistically significant differences were found between the diagnosis methods (P=0.28 for first diagnosis and P=0.17 for top three choices). The confidence intervals for individual raters showed considerable overlap, and the point estimates are almost identical. The mean interreader agreement for complete versus limited HRCT for both top and top three diagnoses were the same (moderate and fair, respectively). The mean intrareader agreement between complete and limited HRCT for top and top three diagnoses were substantial and moderate, respectively. CONCLUSION: Overall reader accuracy and confidence in diagnosis did not significantly differ when fewer or more HRCT images were used.

Determinants of 6-12 month postoperative functional status and pain after elective total hip replacement.

OBJECTIVE: The goal of this pilot project was to quantify outcomes of elective total hip replacement through risk adjustment modeling. DESIGN: A retrospective cohort study of patients who underwent elective total hip replacement (THR) during 1991 at the Orthopaedic and Arthritic Hospital in Toronto. STUDY PARTICIPANTS: All patients undergoing elective total hip replacement with a confirmed diagnosis of osteoarthritis were asked to participate in the study; 193 patients agreed. OUTCOME MEASURES: Participants were asked to complete the WOMAC Osteoarthritis Index and the RAND 36-item Health Survey 6 months to 1 year post-operatively. Pre-operative information on pain and functional status was obtained from the patients' medical record. RESULTS: The results indicate that 93% of patients studied reported at least one significant co-morbidity. The mean pre-operative pain score was 7.5 on a 0-10 scale and average change in pain was 4.8. Regression analyses indicate that increased body mass index is associated with lower post-operative functional status and increased post-operative pain. The amount of pain relief the patient was able to obtain pre-operatively using non-surgical interventions was associated with a better outcome.