Kazunori Tobino, Presenter: Nothing to Disclose

Kuniaki Seyama, Abstract Co-Author: Nothing to Disclose

Masatoshi Kurihara, Abstract Co-Author: Nothing to Disclose

Toyohiro Hirai, Abstract Co-Author: Nothing to Disclose

Taeko Akiyoshi, Abstract Co-Author: Nothing to Disclose

Yoko Gunji, Abstract Co-Author: Nothing to Disclose

Yuzo Kodama, Abstract Co-Author: Nothing to Disclose

Hironobu Nakamura MD, PhD, Abstract Co-Author: Nothing to Disclose

Kazuhisa Takahashi, Abstract Co-Author: Nothing to Disclose

Takeshi Johkoh MD, PhD, Abstract Co-Author: Nothing to Disclose

Noriyuki Tomiyama MD, PhD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To characterize and compare pulmonary cysts in Birt-Hogg-Dubé (BHD) syndrome and those in lymphangioleiomyomatosis (LAM) with quantitative analysis for high-resolution CT (HRCT).

Ten patients with genetically diagnosed BHD syndrome and 10 patients with histologically diagnosed LAM, who had mild cystic lesions in their lungs, were included. Pulmonary cysts were defined as the regions of contiguous pixels having less than -990 HU, and then the size (number of contiguous pixels), location, and number of cysts were automatically determined by a handmade software in all HRCT images. In addition that, the circularity of cysts, which value distributes between 0 and 1 (value is 1 when cyst is perfectly oval), was calculated to characterize the shape.

When we defined the diagnostic criteria of BHD syndrome as the following two items; 1.The area of the pulmonary cysts in the lower lung field is larger than that in the upper lung field and 2. the area of pulmonary cysts in the medial lung field is larger than that in the lateral lung field, a sensitivity and a specificity of differentiation between both diseases were 0.80 (8/10) and 1.00 (10/10), respectively. The maximum value of size of pulmonary cysts was larger in the patients with BHD syndrome than the patients with LAM (BHD; 25.33±18.71, LAM; 9.30±6.26, Mann-Whitney U test, p = 0.04). The value of quartile deviation of circularity was larger in the patients with BHD syndrome than the patients with LAM (BHD; 0.14±0.74, LAM; 0.05±0.02, Mann-Whitney U test, p < 0.001). In differentiation of these diseases, a sensitivity and a specificity were 0.80 (8/10) and 0.70 (7/10), respectively, by the maximum value of size of pulmonary cysts with a cut off value of 9.53 pixels, with those were 0.90 (9/10) and 0.90 (9/10), respectively, by the quartile deviation of the circularity with a cut off value of 0.07.

The characteristics of pulmonary cysts of BHD syndrome and LAM are different, and pulmonary cysts of each disease have distinct features in location, size, distribution, and shape. Quantitative analysis for HRCT is feasible for the differentiation between BHD syndrome and LAM.

Quantitative analysis for HRCT is feasible in differentiating between BHD syndrome and LAM, and may help to understand the difference of patho-physiology of both diseases.

Tobino, K, Seyama, K, Kurihara, M, Hirai, T, Akiyoshi, T, Gunji, Y, Kodama, Y, Nakamura, H, Takahashi, K, Johkoh, T, Tomiyama, N, et al, , Pulmonary Cysts in Birt-Hogg-Dubé Syndrome and Lymphangioleiomyomatosis: Quantitative Analysis for High-Resolution CT.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6015927.html