Pulmonary Emphysema Subtypes on Computed Tomography: The MESA COPD Study

Abstract

Background Pulmonary emphysema is divided into three major subtypes at autopsy: centrilobular, paraseptal and panlobular emphysema. These subtypes can be defined by visual assessment on computed tomography (CT); however, clinical characteristics of emphysema subtypes on CT are not well-defined. We developed a reliable approach to visual assessment of emphysema subtypes on CT and examined if emphysema subtypes have distinct characteristics. Methods The Multi-Ethnic Study of Atherosclerosis COPD Study recruited smokers with COPD and controls age 50–79 years with ≥10 pack-years. Participants underwent CT following a standardized protocol. Definitions of centrilobular, paraseptal and panlobular emphysema were obtained by literature review. Six-minute walk distance and pulmonary function were performed following guidelines. Results Twenty-seven percent of 318 smokers had emphysema on CT. Inter-rater reliability of emphysema subtype was substantial (K:0.70). Compared to participants without emphysema, individuals with centrilobular or panlobular emphysema had greater dyspnea, reduced walk distance, greater hyperinflation, and lower diffusing capacity. In contrast, individuals with PSE were similar to controls, except for male predominance. Centrilobular but not panlobular or paraseptal emphysema was associated with greater smoking history (+21 pack-years P<0.001). Panlobular but not other types of emphysema was associated with reduced body mass index (−5 kg/m2;P=0.01). Other than for dyspnea, these findings were independent of the forced expiratory volume in one second. Seventeen percent of smokers without COPD on spirometry had emphysema, which was independently associated with reduced walk distance. Conclusions Emphysema subtypes on CT are common in smokers with and without COPD. Centrilobular and panlobular emphysema but not paraseptal emphysema have considerable symptomatic and physiological consequences.

Micro–Computed Tomography Comparison of Preterminal Bronchioles in Centrilobular and Panlobular Emphysema

“…The relative contribution of these two processes varies across individuals and emphysematous destruction is further categorized based on its morphology: centrilobular emphysema (CLE), panlobular emphysema (PLE), and paraseptal emphysema (1)(2)(3). These pathologic features underlie various clinical and radiographic manifestations in COPD and, in particular, CLE and PLE have been recognized as distinct pathologic phenotypes (3)(4)(5)(6). Histologic comparisons have shown that emphysematous destruction is more heterogeneous and small airway disease is more severe in CLE than in PLE (4,5,7).…”

“…This imaging technique has been widely used to describe and quantify all of the classic pathologic phenotypes of emphysematous destruction in COPD (3,6,9) and to measure the changes in lumen and wall of airways 2 mm in diameter and larger (10)(11)(12). Although new-generation CT scanners have the potential for greater resolution without an increase in radiation dose (13,14) and may enable measurements of airways less than 2 mm in diameter, it is not currently possible to resolve the small conducting airways down to the level of the terminal bronchioles.…”

“…Greater heterogeneity in parenchyma destruction, as evidenced by an increase in the CV% of interalveolar wall distances, has been previously reported in CLE (4, 5, 7) and was present in this study with relatively small sample size ( Table 2). CLE is known to be related to the deposition of inhaled particles, such as cigarette smoke (6,32). As the movement of gas shifts from bulk flow to diffusion in the transitional region of the airways (33), it is a reasonable assumption that the deposition of the smaller airborne particles will target this region of the lung because particles diffuse much more slowly than gases.…”

Present and future utility of computed tomography scanning in the assessment and management of COPD

“…CT imaging can visualise these different sub-types. One study using a visual scoring system found that centrilobular emphysema was the most common sub-type but over half of patients with emphysema had multiple sub-types [53]. An automated method, called local histogram-based emphysema patterns involves dividing the lung into small cubes and analysing the sub-type of emphysema present in each cube.…”

Diagnostics of Hyperinflation and Emphysema in Patients With Asthma and Copd Overlap on the Primary and Specialized Levels of Medical Care

“…Це відповідає літературним даним про те, що най-більш частим варіантом емфіземи у хворих на ХОЗЛ є саме центрилобулярне ураження з переважно верхньо-дольовою локалізацією [23].…”