Hariri L.P.,Massachusetts General Hospital |
Hariri L.P.,Harvard University |
Mark E.J.,Harvard University |
Suter M.J.,Pulmonary and Critical Care Unit |
Suter M.J.,Massachusetts General Hospital
Archives of Pathology and Laboratory Medicine | Year: 2012
Optical coherence tomography (OCT) is a nondestructive, high-resolution imaging modality, providing crosssectional, architectural images at near histologic resolutions, with penetration depths up to a few millimeters. Optical frequency domain imaging is a second-generation OCT technology that has equally high resolution with significantly increased image acquisition speeds and allows for large area, high-resolution tissue assessments. These features make OCT and optical frequency domain imaging ideal imaging techniques for surface and endoscopic imaging, specifically when tissue is unsafe to obtain and/ or suffers from biopsy sampling error. This review focuses on the clinical impact of OCT in coronary, esophageal, and pulmonary imaging and the role of the pathologist in interpreting high-resolution OCT images as a complement to standard tissue pathology.
Wongviriyawong C.,Harvard University |
Wongviriyawong C.,Massachusetts Institute of Technology |
Harris R.S.,Pulmonary and Critical Care Unit |
Zheng H.,Harvard University |
And 3 more authors.
Journal of Applied Physiology | Year: 2012
Heterogeneity in narrowing among individual airways is an important contributor to airway hyperresponsiveness. This paper investigates the contribution of longitudinal heterogeneity (the variability along the airway in crosssectional area and shape) to airway resistance (Raw). We analyzed chest high-resolution computed tomography scans of 8 asthmatic (AS) and 9 nonasthmatic (NA) subjects before and after methacholine (MCh) challenge, and after lung expansion to total lung capacity. In each subject, Raw was calculated for 35 defined central airways with >2 mm diameter. Ignoring the area variability and noncircular shape results in an underestimation of Raw (%U total) that was substantial in some airways (̃50%) but generally small (median <6%). The average contribution of the underestimation of Raw caused by longitudinal heterogeneity in the area (%U area) to %U total was 36%, while the rest was due to the noncircularity of the shape (%U shape). After MCh challenge, %U area increased in AS and NA (P < 0.05). A lung volume increase to TLC reduced %U total and %U area in both AS and NA (P < 0.0001, except for %U total in AS with P < 0.01). Only in NA, %U shape had a significant reduction after increasing lung volume to TLC (P < 0.005). %U area was highly correlated, but not identical to the mean-normalized longitudinal heterogeneity in the cross-sectional area [CV 2(A)] and %U shape to the average eccentricity of the elliptical shape. This study demonstrates that Raw calculated assuming a cylindrical shape and derived from an average area along its length may, in some airways, substantially underestimate Raw. The observed changes in underestimations of Raw with the increase in lung volume to total lung capacity may be consistent with, and contribute in part to, the differences in effects of deep inhalations in airway function between AS and NA subjects. Copyright © 2012 the American Physiological Society.