How radiology can help pulmonary tuberculosis diagnosis: analysis of 49 patients

To identify the most frequent radiological findings of pulmonary tuberculosis using CT of the chest, to determine those with the highest degree of correlation, and, if possible, to identify the most suggestive radiological findings for acid-fast bacilli (AFB) positive disease.

The radiological and clinical data of 49 patients submitted to CT during diagnosis were retrospectively analysed. The association between findings was assessed using Fisher's exact test, while correlation at CT scan was evaluated with the Spearman analysis.

Bronchiectasis/bronchioloectasis (89.8%), nodule(s) (81.6%), tree-in-bud (TIB), and consolidation (79.6% each) figured among the most common parenchymal findings. Lymphadenopathy (26.5%) was the most common nodal finding. TIB and cavity showed the highest correlation (r = 0.577), followed by TIB and bronchi(olo)ectasis (r = 0.498), TIB and consolidation (r = 0.497), nodule(s), and ground glass opacity (r = 0.488). High correlation was found in only the seven most frequent parenchymal findings. Consolidation, TIB, and cavity were useful to predict the AFB stain positivity.

Our series confirms the extreme heterogeneity of pulmonary tuberculosis. It also proves there are couple of findings which can drive us to the right diagnosis. While a triad of findings predicts AFB positivity, we have not found any predictive sign of AFB negativity; consequently, all patients with suspected imaging and clinical findings for TB should be isolated.