The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners. This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm x 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm x 16 or 0.5 mm x 64 detector-row CT scanner operating at 150 mAs. Images from both scanners were reconstructed at 0.1-mm intervals; the slice thickness was 0.25 mm for the U-HRCT scanner and 0.5 mm for the C-HRCT scanners. For both scanners, the display field of view was 80 mm. The image noise of each scanner was evaluated using a phantom. U-HRCT and C-HRCT images of 53 images selected from 37 lung nodules were then observed and graded using a 5-point score by 10 board-certified thoracic radiologists. The images were presented to the observers randomly and in a blinded manner. The image noise for U-HRCT (100.87 ± 0.51 Hounsfield units [HU]) was greater than that for C-HRCT (40.41 ± 0.52 HU; P < .0001). The image quality of U-HRCT was graded as superior to that of C-HRCT (P < .0001) for all of the following parameters that were examined: margins of subsolid and solid nodules, edges of solid components and pulmonary vessels in subsolid nodules, air bronchograms, pleural indentations, margins of pulmonary vessels, edges of bronchi, and interlobar fissures. Despite a larger image noise, the prototype U-HRCT scanner had a significantly better image quality than the C-HRCT scanners.

Endobronchial ultrasound elastography is a new technique for describing the stiffness of tissue during endobronchial ultrasound-guided transbronchial needle aspiration. The aims of this study were to evaluate the utility of endobronchial ultrasound elastography for mediastinal and hilar lymph nodes, and to compare the elastographic patterns of lymph nodes with results from endobronchial ultrasound-guided transbronchial needle aspiration. Seventy-five lymph nodes were evaluated. A convex probe endobronchial ultrasound was used with a new endoscopic ultrasound processor to assess elastographic patterns that were classified based on color distribution as follows: Type 1, predominantly non-blue (green, yellow and red); Type 2, part blue, part non-blue (green, yellow and red); Type 3, predominantly blue. The elastographic patterns were compared with the final pathologic results from endobronchial ultrasound-guided transbronchial needle aspiration. On pathological evaluation of the lymph nodes, 33 were benign and 42 were malignant. The lymph nodes that were classified as Type 1 on endobronchial ultrasound elastography were benign in 24/24 (100%); for Type 2 lymph nodes, 6/14 (46.9%) were benign and 8/14 (57.1%) were malignant; Type 3 lymph nodes were benign in 2/37 (5.4%) and malignant in 35/37 (94.6%). In classifying Type 1 as ‘benign’ and Type 3 as ‘malignant,’ the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy rates were 100, 92.3, 94.6, 100 and 96.7%, respectively. Endobronchial ultrasound elastography of mediastinal and hilar lymph nodes is a noninvasive technique that can be performed reliably and may be helpful in the prediction of nodal metastasis during endobronchial ultrasound-guided transbronchial needle aspiration.

Purpose To clarify the percentage of solitary pure ground-glass nodules (SPGGNs) 5 mm or smaller that grow and develop into invasive adenocarcinomas. Materials and Methods This study was approved by the institutional review board, and informed consent was obtained from all people who were screened. From February 2004 through December 2007, 7294 participants underwent screening for lung cancer with computed tomographic (CT) imaging. The nodule database was reviewed to identify SPGGNs 5 mm or smaller. Growth of the SPGGNs was evaluated as of March 31, 2013. In cases of pathologic analysis–proven adenocarcinomas that developed from SPGGNs 5 mm or smaller, solid components were evaluated. Percentages, 95% confidence intervals, and means were calculated. Results At baseline screening, 438 SPGGNs 5 mm or smaller were identified, and during the study period one SPGGN 5 mm or smaller developed de novo. Of the 439 SPGGNs, 394 were stable and 45 (10.3% [95% confidence interval: 7.5%, 13.7%]), including newly developed SPGGN, grew. Of the 45 SPGGNs that grew, 0.9% (four of 439 [95% confidence interval: 0.3%, 2.3%]) developed into adenocarcinomas (two minimally invasive [including the newly developed SPGGN] and two invasive). The mean period between baseline CT screening and the appearance of solid components in the four adenocarcinomas was 3.6 years. Conclusion Of SPGGNs 5 mm or smaller, approximately 10% will grow and 1% will develop into invasive adenocarcinomas or minimally invasive adenocarcinomas. SPGGNs 5 mm or smaller should be rescanned 3.5 years later to look for development of a solid component. ^© RSNA, 2015

Background: Diagnostic bronchoscopy has been considered as a safe and effective procedure. Endobronchial ultrasound with a guide sheath (EBUS-GS) for the diagnosis of peripheral pulmonary lesions (PPLs) is becoming a common procedure, but reports about its safety are missing. Objectives: The aim of this study was to evaluate the safety profile of EBUS-GS for the diagnosis of PPLs. Methods: All patients with PPLs who underwent EBUS-GS between September 2012 and August 2014 at the National Cancer Center Hospital were included. Postprocedural complications and the durability of devices were retrospectively reviewed. Results: During the study period, EBUS-GS procedures were performed for 965 PPLs. The overall complication rate was 1.3% (13/965): 0.8% (8/965) for pneumothorax and 0.5% (5/965) for pulmonary infection. There was no significant hemorrhage, air embolism, tumor seeding or procedure-related death, and there was no breakage of the guide sheath. Only four radial probes were broken during the study period without any adverse reactions. Conclusions: EBUS-GS is a tolerable procedure, and the devices are durable.