Computed tomography-based centrilobular emphysema subtypes relate with pulmonary function.
BACKGROUND
Centrilobular emphysema (CLE) is recognized as low attenuation areas (LAA) with centrilobular pattern on high-resolution computed tomography (CT). However, several shapes of LAA are observed. Our preliminary study showed three types of LAA in CLE by CT-pathologic correlations. This study was performed to investigate whether the morphological features of LAA affect pulmonary functions.


METHODS
A total of 73 Japanese patients with stable CLE (63 males, 10 females) were evaluated visually by CT and classified into three subtypes based on the morphology of LAA including shape and sharpness of border; patients with CLE who shows round or oval LAA with well-defined border (Subtype A), polygonal or irregular-shaped LAA with ill-defined border (Subtype B), and irregular-shaped LAA with ill-defined border coalesced with each other (Subtype C). CT score, pulmonary function test and smoking index were compared among three subtypes.


RESULTS
Twenty (27%), 45 (62%) and 8 cases (11%) of the patients were grouped into Subtype A, Subtype B and Subtype C, respectively. In CT score and smoking index, both Subtype B and Subtype C were significantly higher than Subtype A. In FEV1%, Subtype C was significantly lower than both Subtype A and Subtype B. In diffusing capacity of lung for carbon monoxide, Subtype B was significantly lower than Subtype A.


CONCLUSIONS
The morphological differences of LAA may relate with an airflow limitation and alveolar diffusing capacity. To assess morphological features of LAA may be helpful for the expectation of respiratory function.
Department of Respiratory Medicine and Allergology, Sapporo Medical University, School of Medicine, South-1 West-16, Chuo-ku, Sapporo 060-8543, Japan ; Department of Respirology, NTT East Corporation Sapporo Hospital, South-1 West-15, Chuo-ku, Sapporo 060-0061, Japan.
Mamoru
M
Takahashi
Gen
G
Yamada
Hiroyuki
H
Koba
Hiroki
H
Takahashi
CT.; Centrilobular emphysema; pulmonary function test; subtype