To explore HRCT appearances and differential diagnosis of diffuse pulmonary miliary nodules in patients with acquired immunodeficiency syndrome (AIDS).

The thoracic CT scans obtained in 112 AIDS patients with diffuse miliary nodules and one single diagnosis were retrospectively analyzed for distribution of nodules and for coexistent findings of consolidation,cavity formation,“tree-in-bud”pattern,nodules (10-30 mm in diameter),lymphadenopathy,and hepatoslpenomegaly.

Of the 112 patients,57 had mycobacterium tuberculosis infections,45 had fungal infections (34 cases of marneffei penicillium,9 aspergillus,2 mucomycosis),10 had bacterial infections (5 cases of staphylococcus,3 klebsiella pneumoniae,1 streptococcus mitis,and 1 measles twin cocci).The predominant distribution pattern of tuberculous and fungal infections was random distribution.Lobular center distribution and the coexistence of random distribution and lobular center distribution were also observed.Patients with bacterial infections had a lobular center distribution.Of all the 112 patients,CT findings were compared between penicilliosis marneffei and tuberculosis infections.The presence of pleural effusion was closely related to mycobacterium tuberculosis (31 vs.5χ²=14.024,P<0.01),while lymphadenopathy in the small bowel mesentery was related to Penicillium marneffei infection (17 vs.5χ²=23.015,P<0.01).

In patients with AIDS who have diffuse pulmonary miliary nodules at HRCT,distribution of nodules were of no use in the differentiation of potential infectious causes.Other coexistent findings may contribute to the differential diagnosis.

Acquired immunodeficiency syndrome; Multiple pulmonary nodules; Tomography,X-ray computed