Influence of liquid crystal display monitors on observer performance for detection of diffuse pulmonary disease on chest radiographs.

PURPOSE: The purpose of this study was to assess the influence of liquid crystal display (LCD) monitors on the detectability of diffuse pulmonary diseases depicted on chest radiographs by comparing them with a high-resolution cathode ray tube (CRT) monitor. MATERIALS AND METHODS: A group of 17 radiologists interpreted 87 soft-copy images on LCD monitors with pixel arrays of 1024 x 1280, 1200 x 1600, 1536 x 2048, and 2048 x 2560 and on a CRT monitor with a pixel array of 2048 x 2560. They were asked to indicate their individual confidence levels regarding the presence of diffuse pulmonary diseases. The luminance distributions of all monitors were adjusted to the same distributions, and the ambient illumination was 200 lux. Observer performance was analyzed in terms of the receiver operating characteristics (ROC). RESULTS: The average ROC curves for the five monitor types were similar, and there were no statistically reliable effects of the five monitor types on the readers' diagnostic performances (P = 0.7587). CONCLUSION: The detectability of diffuse pulmonary disease on the LCD monitors with a spatial resolution equal to or higher than a matrix size of 1024 x 1280 was found to be equivalent to that on the high-resolution CRT monitor.

Effects of monitor luminance change on observer detection performance.

To confirm that the dimming luminance change in the CRT monitor will have a detrimental effect on diagnostic performance, we performed the four-alternative forced choice experiments on the CRT monitor with the 11 luminance conditions simulating CRT degraded by long-term usage. Six radiologists and one pulmonary physician performed a detection task for 11,000 test areas on 110 test images. The 11 monitor conditions significantly affected the correct detection rates of simulated nodules in the four-alternative forced choice experiments. The gradual deterioration in CRT monitor luminance will have certainly a detrimental effect on detection performance.

Influence of monitor luminance change on observer performance for detection of abnormalities depicted on chest radiographs.

RATIONALE AND OBJECTIVES: To investigate how changes in luminance affect the detection accuracy of radiologists viewing chest radiograph images on high-resolution CRT monitors. MATERIALS AND METHODS: Thirteen radiologists performed a detection task for 11 chest radiograph images with simulated nodules on a monitor with 11 luminance conditions (the maximum luminance ranges from 157.4-369.0 candela/m2) simulating CRT degraded by long-term usage, under the ambient illumination of 200 lux; the observation order was always from the darkest to the brightest. RESULTS: There was a statistically reliable effect of the 11 monitor display conditions on the detection of nodules (P < 0.001). In the conditions in which the maximum luminance of the CRT was 60.7% or below that of the standard display luminance, the correctly detected nodule number reliably deteriorated. CONCLUSIONS: The luminance change in CRT monitor display under long-term usage will have a detrimental effect on nodule detection performance in chest radiograph images.

Uptake of 18F-FDG in acute aortic dissection: a determinant of unfavorable outcome.

UNLABELLED: Imaging with (18)F-FDG PET/CT is able to reveal vascular inflammation, and several studies have shown that increased (18)F-FDG uptake in carotid artery plaques can qualify the degree of atherosclerotic inflammation. However, clinical assessment of acute aortic dissection (AAD) by PET/CT remains largely unexplored. This study aimed to investigate the use of (18)F-FDG PET/CT to predict short- and midterm outcomes in medically controlled AAD patients. METHODS: A total of 28 medically treated AAD patients (2 Stanford type A and 26 type B, aged 69.5 +/- 11.6 y) were prospectively studied. All patients were examined by enhanced CT for diagnosis of AAD and underwent serial imaging studies during follow-up. PET/CT images were acquired 50 and 100 min after (18)F-FDG injection in all patients in the acute phase. RESULTS: Of the 28 patients, 8 who had an unfavorable outcome due to death from rupture (n = 2), surgical repair (n = 4), and progression of dissection (n = 2) were categorized as having unfavorable AAD. The remaining 20 patients were categorized as having favorable AAD. Maximum dissection diameter in the unfavorable group was significantly greater than that in the favorable group (P = 0.0207). On 50-min images, maximal and mean standardized uptake values (SUVs) at maximum aortic dissection sites were significantly greater for the unfavorable group than for the favorable group (all P < 0.01). A stepwise-forward selection procedure demonstrated that the mean SUV at sites of maximum aortic dissection on 50-min images significantly and independently predicted an unfavorable outcome for AAD (P = 0.0171; odds ratio, 7.72; 95% confidence interval, 1.44-41.4; R(2) = 0.2372). A mean SUV greater than 3.029 had significant predictive power, with sensitivity of 75.0%, specificity of 70.0%, a positive predictive value of 50.0%, a negative predictive value of 87.5%, and accuracy of 71.4%. CONCLUSION: Greater uptake of (18)F-FDG in AAD was significantly associated with an increased risk for rupture and progression. (18)F-FDG PET/CT may be used to improve AAD patient management, although more studies are still needed to clarify its role in this clinical scenario.