Lower-lobe shrinkage relative to total lung volume in collagen vascular diseases.
OBJECTIVE
It has been reported that the prognosis differs between patients who have collagen vascular diseaseassociated interstitial pneumonia (CVD-IP) and those with idiopathic IP (IIP). In this study, chest computed tomography (CT) findings were compared between patients with CVD-IP and IIP.


METHODS
A retrospective analysis was performed of 47 consecutive patients (23 with CVD-IP and 24 with IIP). The lower-lobe volume (LLV), total lung volume (TLV), and their ratio (LLV/TLV) were determined by volumetry using three-dimensional computed tomography (CT).


RESULTS
There was no significant difference of the LLV/TLV ratio between the CVD-IP and IIP groups. However, the LLV/TLV ratio was <0.33 in 9/23 patients with CVD-IP versus 2/24 patients with IIP, and there was a significant difference in the percentage of patients with a ratio<0.33 between the CVD-IP and IIP groups (p = 0.01). The LLV/TLV ratio was not influenced by the severity of lung disease.


CONCLUSIONS
Measuring the LLV/TLV ratio by threedimensional CT can help distinguish between CVD-IP and IIP at initial diagnosis, especially in patients with CVD-IP who have pulmonary involvement before other organ diseases and symptoms caused by CVD.
Watanabe
M
M
Department of Respirology and Rheumatology, Faculty of Medicine, Tottori University, 36-1 Nishimachi, Yonago, 683-8504, Japan. watanabm@grape.med.tottori-u.ac.jp
Igishi
T
T
Burioka
N
N
Kurai
J
J
Fukuoka
Y
Y
Kato
K
K
Yamasaki
A
A
Hasegawa
Y
Y
Okazaki
R
R
Shimizu
E
E
D000368:Aged; D016022:Case-Control Studies; D003095:Collagen Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging* / Q000473:pathology; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014652:Vascular Diseases / Q000000981:diagnostic imaging* / Q000473:pathology