[Clinicoradiologic characteristics of active pulmonary tuberculosis with perilymphatic involvement]

To evaluate the prevalence of perilymphatic involvement and clinicoradiologic characteristics of active pulmonary tuberculosis according to the distribution of micronodules on CT images.

A total of 124 in-patients with active pulmonary tuberculosis in Haihe Clinical College of Tianjin Medical University from September 2013 to March 2015 were enrolled in this study, all patients underwent CT before antituberculosis therapy.A retrospective investigation of CT images focused on the distribution of micronodules, as well as other major CT features of active pulmonary tuberculosis.Clinical and CT findings of the three groups which based on the distribution of micronodules (perilymphatic, centrilobular and mixed) were compared.

All patients existed micronodules.Among these patients, the number of the perilymphatic micronodules, interlobular septal thickening, intralobular septal thickening, bronchial or bronchovascular bundle thickening, galaxy or cluster sign, reversed halo sign was 80(64.5%), 83(66.9%), 56(45.2%), 56(45.2%), 17(13.7%) and 4(3.2%), respectively.There were 35, 36 and 45 cases who were classified into the perilymphatic, centrilobular and mixed groups, respectively.Interlobular septal thickening (88.6% vs 38.9%), intralobular septal thickening (97.1% vs 0), bronchial or bronchovascular bundle thickening (74.3% vs 19.4%) and galaxy or cluster sign (37.1% vs 0) in perilymphatic group were higher than those of centrilobular group, consolidation or macronodule (80% vs 100%) and cavitation (42.9% vs 77.8%) in perilymphatic group were lower than those of centrilobular group. Age (32±16 vs 41±14), the rate of sputum acid-fast bacilli smears staining positive (28.6% vs 58.3%) and sputum culture positive for Mycobacterium tuberculosis (54.3% vs 94.4%) in perilymphatic group were lower than those of centrilobular group.

CT findings representing pulmonary perilymphatic involvement are relatively common in patients with active tuberculosis, galaxy or cluster sign and reversed halo sign are uncommon. The patients with tuberculosis are relatively younger who principally showed pulmonary perilymphatic involvement, and detection of sputum Mycobacterium tuberculosis in these patients is relatively lower.