Search

The emerging role of quantitative computed tomography (CT) in the evaluation of pulmonary emphysema is reviewed. CT is primarily used in the clinical setting to assess lung morphology visually. Increasingly treatments are being developed to treat patients with emphysema that require accurate quantitation of extent and distribution of the process. In addition, functional assessment can be made by inference of detailed anatomic correlates and by direct measurement of regional function using dynamic scan protocols. The aim of this review is to summarize the current role of imaging in the assessment of patients with emphysema. The review will focus on CT for the evaluation of morphologic abnormalities and on the potential role for the evaluation of functional abnormalities and treatment targeting.

The efficacies of inhaled pharmacologic drugs in the prophylaxis and treatment of airway diseases could be improved if particles were selectively directed to appropriate sites. In the medical arena, planar gamma scintillation cameras may be employed to study factors affecting such particle deposition patterns within the lung. The value and versatility of such instruments, however, are compromised by the limited resolution of their images. Specifically, it is not possible to determine the composition of their central (C) or large airway, intermediate (I), and peripheral (P) or small airway zones. We present an analytical model to assist the clinician in the systematic analysis and interpretation of gamma camera images. Using the Cray Y-MP supercomputer, a range of human lung morphologies has been mapped to function as templates that can be superimposed on scans. The model is intended to complement laboratory regimens by providing a previously unavailable method to define the C, I, and P zones of the human lung generation by generation. A quantitative value now can be assigned to the degree of overlapping that exists in the images. For example, for a "typical" lung morphology consisting of 16,777,215 airways (total), the C zone itself may contain 1,608,246 airways, of which 1,595,940, or 99.2%, are alveolated airways. By identifying composition, our intent is to integrate the model into future aerosol therapy protocols and thereby assist procedures that target delivery of airborne pharmaceuticals.

To the Editor, I read with great interest the article by Han et al,1 who studied lung morphology in developing endothelial NO synthase (eNOS)-deficient mice. The authors presented exciting data on defective peripheral lung vessel development, which was combined with impaired alveolar maturation. These data reflect very well the current thinking of lung development regulated by molecular cross-talk between mesenchymal and epithelial elements.2 One main point suggested by the …