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To determine the optimal surface-rendering threshold value for three-dimensional (3D) endoluminal computed tomographic (CT) colonographic images for accurate manual polyp measurement, with direct measurement of simulated polyps as the reference standard, and to assess the agreement between manual 3D measurements and automated measurements.Institutional review board approval was not required for the experimental study with pig colons obtained at an abattoir but was obtained for the use of patient data, with waiver of informed consent. Eighty-six simulated polyps (reference size, 3-15 mm) and 14 human polyps (approximate size, 5-20 mm) were included. Automated polyp measurements and manual measurements with endoluminal views that were surface rendered at threshold values of -800, -700, -600, and -500 HU were performed by one observer. Agreement between CT colonographic measurements and reference sizes and between manual and automated measurements were assessed by using the Bland-Altman method.For simulated polyps, mean measurement difference between the observed size and reference size was 0.86 mm (95% limits of agreement: -0.52 mm, 2.24 mm), 0.55 mm (95% limits of agreement: -0.75 mm, 1.85 mm), 0.20 mm (95% limits of agreement: -1.11 mm, 1.50 mm), and -0.08 mm (95% limits of agreement: -1.43 mm, 1.27 mm) for -800, -700, -600, and -500 HU, respectively. Mean measurement difference was 0.09 mm (95% limits of agreement: -1.49 mm, 1.67 mm) for automated measurement. Manual polyp size at -500 HU (P = .277) and automated polyp size (P = .288) were not significantly different from reference size. For human polyps, 10 polyps, excluding four lesions that were large, lobulated, or located adjacent to an edge of the haustral fold, showed accurate automated demarcation of lesion boundaries. Automated measurements of the 10 polyps showed the closest agreement with manual measurements at -500 HU.The optimal surface-rendering threshold value for accurate polyp measurement is approximately -500 HU. Automated measurements agree closely with manual measurements at the optimal threshold value for well-circumscribed smooth rounded polyps.

To compare prospectively obtained static two-dimensional (2D) and three-dimensional (3D) ultrasonographic (US) images in the diagnostic performance of radiologists with respect to the differentiation of benign from malignant solid breast masses with histopathologic examination as the reference standard.This study had institutional review board approval, and patient informed consent was obtained. Conventional 2D and 3D US images were obtained from 141 patients (age range, 25-71 years; mean age, 46 years) with 150 solid breast masses (60 cancers and 90 benign lesions) before excisonal or needle biopsy. Four radiologists who had not performed the examinations independently reviewed 2D US images and stored 3D US data and provided a level of suspicion concerning probability of malignancy. The sensitivity, specificity, and negative predictive values of 2D images were compared with those of 3D US images.For all readers, 3D US images were the same as or better than 2D US images in terms of sensitivity (100% vs 100% for reader 1; 100% vs 98% for reader 2; 98% vs 93% for reader 3; 93% vs 92% for reader 4), specificity (58% vs 56% for reader 1; 51% vs 46% for reader 2; 83% vs 72% for reader 3; 86% vs 84% for reader 4), and negative predictive values (100% vs 100% for reader 1; 100% vs 98% for reader 2; 99% vs 94% for reader 3; 95% vs 94% for reader 4). These differences, however, were not statistically significant (P.05).The performance of the radiologists with respect to the characterization of solid breast masses with static 2D US images was similar to that with 3D US data.

To assess the frequency and degree of air trapping at thin-section computed tomography (CT) of the lung in relation to age and smoking history in asymptomatic subjects.Thin-section CT of the lung was performed prospectively at end inspiration and end expiration in 82 subjects (27 smokers, 55 nonsmokers) without any history of pulmonary diseases and without present pulmonary symptoms. The frequency and degree of air trapping were evaluated according to age and smoking status.The overall frequency of air trapping was 52% (43 of 82 subjects, kappa = 0.72). Air trapping was found in three of 13 (23%), seven of 17 (41%), nine of 18 (50%), 11 of 17 (65%), and 13 of 17 (76%) subjects aged 21-30, 31-40, 41-50, 51-60, and greater than or equal to 61 years, respectively. The frequency of air trapping increased with age (P.05). The degree of air trapping had a significant correlation with age (r = 0.523, P.001) and was higher in smokers with a smoking history of more than 10 pack-years (P.05).Air trapping was found in approximately 50% of asymptomatic subjects. The frequency of air trapping increased with age, and its severity increased with age and smoking.