Transient radiographic progression during initial treatment of pulmonary tuberculosis: CT findings

Purpose: A study was undertaken to describe the thin-section CT features of transient radiographic progression during initial treatment of active pulmonary tuberculosis. Method: The CT scans of 13 patients who developed transient radiographic progression during initial treatment of pulmonary tuberculosis were evaluated and compared with those of 10 patients with true progression of pulmonary tuberculosis. Two patients underwent transbronchial lung biopsy for pathologic evaluation of new lesion. Results: Eight patients had increased opacity at the site of their original lesion, whereas five had new opacities elsewhere: ipsilateral (n = 3) or contralateral (n = 1) to the original lesion or both (n = 1). Relatively extensive areas of ground-glass attenuation were concomitantly depicted in three of the eight patients with progression in the area of the original lesion. In those with progression ipsilateral or contralateral to the lesion, the character of the new lesions was ground-glass opacity and/or consolidation mainly in the subpleural region. Transbronchial lung biopsy specimens obtained from two patients showed intraluminal organizing exudates and thickened alveolar septa with lymphocyte infiltration, whereas the dominant CT findings of true progression of pulmonary tuberculosis were nodules (n = 8) or centrilobular nodules (n = 7). Conclusion: Thin-section CT may be useful to differentiate transient radiographic progression from true progression of pulmonary tuberculosis.