Computed tomographic based indices of emphysematous lung destruction may highlight differences in disease pathogenesis and further enable the classification of subjects with Chronic Obstructive Pulmonary Disease. While there are multiple techniques that can be utilized for such radiographic analysis, there is very little published information comparing the performance of these methods in a clinical case series. Our objective was to examine several quantitative and semi-quantitative methods for the assessment of the burden of emphysema apparent on computed tomographic scans and compare their ability to predict lung mechanics and function. Automated densitometric analysis was performed on 1094 computed tomographic scans collected upon enrollment into the National Emphysema Treatment Trial. Trained radiologists performed an additional visual grading of emphysema on high resolution CT scans. Full pulmonary function test results were available for correlation, with a subset of subjects having additional measurements of lung static recoil. There was a wide range of emphysematous lung destruction apparent on the CT scans and univariate correlations to measures of lung function were of modest strength. No single method of CT scan analysis clearly outperformed the rest of the group. Quantification of the burden of emphysematous lung destruction apparent on CT scan is a weak predictor of lung function and mechanics in severe COPD with no uniformly superior method found to perform this analysis. The CT based quantification of emphysema may augment pulmonary function testing in the characterization of COPD by providing complementary phenotypic information.

RATIONALE: Lung volume reduction surgery (LVRS) has been demonstrated to provide a functional and mortality benefit to a select group of subjects with chronic obstructive pulmonary disease (COPD). The effect of LVRS on COPD exacerbations has not been as extensively studied, and whether improvement in postoperative lung function alters the risk of disease exacerbations is not known. OBJECTIVES: To examine the effect, and mechanism of potential benefit, of LVRS on COPD exacerbations by comparing the medical and surgical cohorts of the National Emphysema Treatment Trial (NETT). METHODS: A COPD exacerbation was defined using Centers for Medicare and Medicaid Services data and International Classification of Diseases, Ninth Revision, discharge diagnosis. MEASUREMENTS AND MAIN RESULTS: There was no difference in exacerbation rate or time to first exacerbation between the medical and surgical cohorts during the year before study randomization (P = 0.58 and 0.85, respectively). Postrandomization, the surgical cohort experienced an approximate 30% reduction in exacerbation frequency (P = 0.0005). This effect was greatest in those subjects with the largest postoperative improvement in FEV(1) (P = 0.04) when controlling for changes in other spirometric measures of lung function, lung capacities, and room air arterial blood gas tensions. Finally, LVRS increased the time to first exacerbation in both those subjects with and those without a prior history of exacerbations (P = 0.0002 and P < 0.0001, respectively). CONCLUSIONS: LVRS reduces the frequency of COPD exacerbations and increases the time to first exacerbation. One explanation for this benefit may be the postoperative improvement in lung function.

Transcutaneous ultrasound imaging may be used to detect abdominal hemorrhage in the field setting. The Focused Assessment with Sonography for Trauma (FAST) examination was developed to characterize blunt abdominal trauma and has been shown to be effective for assessing penetrating trauma as well. However, it is unlikely that a minimally trained operator could perform a diagnostic examination. In our system, the operator is be supported by real-time 3D volume displays. The operator will be directed through the examination by prompts from a computer system or outside expert, potentially with knowledge of the anatomy of the injured patient. The key elements of the tele-operated FAST exam capability have been demonstrated; the exam is performed with real-time guidance from anatomic images registered to the body. It appears likely that Image Registration will assist hemorrhage detection at the point of injury or in the initial evaluation by a trauma response team.

Delineating the extent and distribution of emphysema is an essential component of the evaluation of candidates for lung volume reduction surgery (LVRS). Imaging also may identify contraindications to LVRS, including bronchiectasis and pleural scarring. The chest X-ray is of limited utility in LVRS evaluation. Chest computed tomography (CT) scanning is an essential component of the evaluation, demonstrating the presence of emphysema and its amount and distribution. Clinical experience has shown that a substantial minority of chest CT scans will also demonstrate pulmonary nodules, some of which represent lung cancers. Published series, including the National Emphysema Treatment Trial, consistently demonstrate that patients with upper lobe predominant or heterogeneous emphysema are most likely to benefit from LVRS. Heterogeneity and distribution can also be assessed by radionuclide ventilation perfusion scanning, but this modality adds little additional information to CT scanning.

Advances in high-resolution computed tomography (CT) imaging are making a full three-dimensional analysis of the lungs feasible. In particular, airway morphology can be studied in vivo and quantitative metrics of airway size and shape can be extracted. The thickening process associated with the inflammatory response in the diseased lung can be quantified by means of image processing techniques that extract the airway lumen and airway wall. In this article, we give an overview of these imaging techniques and their diverse nature. We also offer a comprehensive view of the analysis pipeline for three-dimensional airway trees and a validation framework that is needed to compare different techniques.

Transcutaneous ultrasound imaging may be used to detect abdominal hemorrhage in the field setting. The Focused Assessment with Sonography for Trauma (FAST) examination was developed to characterize blunt abdominal trauma and has been shown to be effective for assessing penetrating trauma as well. However, it is unlikely that a minimally trained operator could perform a diagnostic examination. In our system, the operator is be supported by real-time 3D volume displays. The operator will be directed through the examination by prompts from a computer system or outside expert, potentially with knowledge of the anatomy of the injured patient. The key elements of the tele-operated FAST exam capability have been demonstrated; the exam is performed with real-time guidance from anatomic images registered to the body. It appears likely that Image Registration will assist hemorrhage detection at the point of injury or in the initial evaluation by a trauma response team.