Franquet T, Díaz C, Domingo P, Giménez A, Geli C
Department of Radiology, Hospital de Sant Pau, Universidad Autónoma de Barcelona, Spain.
J Comput Assist Tomogr. 1999 Mar-Apr;23(2):169-73. doi: 10.1097/00004728-199903000-00002.
The purpose of our study was to correlate the extent of air trapping on expiratory CT scans with results of pulmonary function tests (PFTs) in a large group of patients with primary Sjögren syndrome and to determine whether these techniques may be complementary in assessing small airways obstruction.
Thirty-four nonsmoking patients with proven primary Sjögren syndrome and 10 healthy nonsmokers underwent paired inspiratory-expiratory thin section CT and PFTs. Expiratory scans were scored for the presence and extent of areas of air trapping. Extent of air trapping was assessed visually and given a score. The functional significance of the extent of air trapping was evaluated in both groups and then correlated with the results of PFTs.
Bronchiolar abnormalities were seen in 11 (32%) of 34 patients with primary Sjögren syndrome. On the expiratory CT scans, a mosaic pattern of lung attenuation was identified in 17 patients. Air trapping was found in 44 of 204 lobar observations on the expiratory scans. The median point scale score at end-expiration was 3.6 (20%, Grade 1), ranging from 1 (5.5%, Grade 1) to 9 (50%, Grade 2). The mean total score of air trapping was more prevalent in lower (46/68) lobes (22.4%) than in upper (22/136) lobes (5.3%) (p < 0.001). PFTs were normal in the primary Sjögren syndrome patients as well as the healthy subjects. Air trapping was found more frequently in patients with primary Sjögren syndrome than in the healthy group. Only during exhalation was there evidence of minimal lobular-sized areas or air trapping (Grade 1) in three of the healthy subjects. We did not find any correlation between air trapping and PFTs including the forced expiratory flow rate between 25 and 75% of the forced vital capacity (FEF25-75).
Expiratory high resolution CT revealed the extent of bronchiolar disease in patients with primary Sjögren syndrome. We also found that the extent of air trapping did not correlate with PFTs, which suggests the existence of a subclinical bronchiolar inflammatory process that may precede detectable abnormalities in lung function tests.
我们研究的目的是在一大组原发性干燥综合征患者中，将呼气CT扫描上的空气潴留程度与肺功能测试（PFT）结果相关联，并确定这些技术在评估小气道阻塞方面是否具有互补性。
34例经证实的原发性干燥综合征非吸烟患者和10名健康非吸烟者接受了吸气-呼气薄层CT和PFT检查。对呼气扫描进行评分，以确定空气潴留区域的存在和范围。通过视觉评估空气潴留的程度并给出评分。在两组中评估空气潴留程度的功能意义，然后将其与PFT结果相关联。
34例原发性干燥综合征患者中有11例（32%）出现细支气管异常。在呼气CT扫描中，17例患者发现肺实质衰减的马赛克样表现。在呼气扫描的204个肺叶观察中，44个发现有空气潴留。呼气末的中位数评分是3.6（20%，1级），范围从1（5.5%，1级）到9（50%，2级）。空气潴留的平均总分在下叶（46/68）（22.4%）比上叶（22/136）（5.3%）更常见（p<0.001）。原发性干燥综合征患者和健康受试者的PFT均正常。原发性干燥综合征患者中发现空气潴留的频率高于健康组。仅在呼气时，3名健康受试者中有证据显示存在最小的小叶大小区域或空气潴留（1级）。我们未发现空气潴留与包括用力肺活量25%至75%之间的用力呼气流量（FEF25-75）在内的PFT之间存在任何相关性。
呼气高分辨率CT显示了原发性干燥综合征患者细支气管疾病的程度。我们还发现空气潴留程度与PFT不相关，这表明存在一种亚临床细支气管炎症过程，可能在肺功能测试中可检测到的异常之前出现。
