Enhanced pneumothorax visualization in ICU patients using portable chest radiography.

OBJECTIVE: Pneumothorax development can cause precipitous deterioration in ICU patients, therefore quick and accurate detection is vital. Portable chest radiography is commonly performed to exclude pneumothoraces but is hampered by supine patient position and overlying internal and external material. Also, the initial evaluation of the chest radiograph may be performed by a relatively inexperienced physician. Therefore, a tool that could significantly improve pneumothorax detection on portable radiography would be helpful in patient care. The aim of this study was to evaluate the clinical utility of novel enhancement software for pneumothorax detection in readers with varied clinical experience of detecting/excluding pneumothoraces on portable chest radiographs in ICU patients. SUBJECTS AND METHODS: 206 portable ICU chest radiographs, 103 with pneumothoraces, were processed with and without enhancement software and reviewed by 5 readers who varied in reading experience. Images were grouped for different complexity levels. RESULTS: The mean AUC for pneumothorax detection increased for 4/5 readers from 0.846-0.957 to 0.88-0.971 with a largest improvement for the reader with least experience. No significant change was noted for the reader with the longest reading experience. The image complexity had no impact on the interpretation result. CONCLUSION: Pneumothorax detection improves with novel enhancement software; the largest improvement is seen in less experienced readers.

Use and misuse of waterfall plots.

BACKGROUND: "Waterfall plots" are used to describe changes in tumor size observed in clinical studies. Here we assess criteria for generation of waterfall plots and the impact of measurement error in generating them. METHODS: We reviewed published waterfall plots to investigate variability in criteria used to define them. We then compared waterfall plots generated by different observers for 24 patients enrolled in a completed phase I study of solid tumors with available computed tomography (CT) scans. Tumor measurements were made independently from CT scans according to Response Evaluation Criteria in Solid Tumors 1.1 by four board-certified radiologists and four medical oncologists. Interobserver variability was quantified and compared with reference measurements reported for the phase 1 study. All statistical tests were two-sided. RESULTS: There was substantial variability in criteria used to generate published waterfall plots. In the internal study, the results were statistically significantly different between all eight readers (P = .01, variance = 197.1, SD = 14.0) and between the oncologists (P = .01, variance = 319.0, SD = 17.9), but not between the radiologists (P = .68, variance = 70.8, SD = 8.4). Different observers classified one to five patients as having a partial response and 12-19 patients as having stable disease. Similar variability in categorization of response was observed when these error rates were applied to published waterfall plots. CONCLUSION: Waterfall plots are subject to substantial variability in criteria used to define them and are influenced by measurement errors; they should be generated by trained radiologists. Caution should be exercised when interpreting results of waterfall plots in the context of clinical trials.

Liver resection after chemotherapy and tumour downsizing in patients with initially unresectable colorectal cancer liver metastases.

OBJECTIVES: Among patients with initially unresectable colorectal cancer liver metastases (CLM), a subset are rendered resectable following the administration of systemic chemotherapy. This study reports the results achieved in liver resections performed at a single hepatobiliary referral centre after downsizing chemotherapy in patients with initially unresectable CLM. METHODS: All liver resections for CLM performed over a 10-year period at the Toronto General Hospital were considered. Data on initially non-resectable patients who received systemic therapy and later underwent surgery were included for analysis. RESULTS: Between January 2002 and July 2012, 754 liver resections for CLM were performed. A total of 24 patients were found to meet the study inclusion criteria. Bilobar CLM were present in 23 of these 24 patients. The median number of tumours was seven (range: 2-15) and median tumour size was 7.0 cm (range: 1.0-12.8 cm) before systemic therapy. All patients received oxaliplatin- or irinotecan-based chemotherapy. Fourteen patients received combined treatment with bevacizumab. Negative margin (R0) resection was accomplished in 21 of 24 patients. There was no perioperative mortality. Ten patients suffered perioperative morbidity. Eighteen patients suffered recurrence of disease within 9 months. Rates of disease-free survival at 1, 2 and 3 years were 47.6% [95% confidence interval (CI) 30.4-74.6%], 23.8% (95% CI 11.1-51.2%) and 19.0% (95% CI 7.9-46.0%), respectively. Overall survival at 1, 2 and 3 years was 91.5% (95% CI 80.8-100%), 65.3% (95% CI 48.5-88.0%) and 55.2% (95% CI 37.7-80.7%), respectively. CONCLUSIONS: Liver resection in initially unresectable CLM can be performed with low rates of morbidity and mortality in patients who respond to systemic chemotherapy, although these patients do experience a high frequency of disease recurrence.