[Thoracic manifestation of tuberculosis]

Tuberculosis (TB) is a granulomatous disease caused by Mycobacterium tuberculosis and transmission is via an airborne route by droplet infection. In the majority of cases patients have thoracic TB, which most frequently presents with hilar lymphadenopathy and pulmonary manifestation. Due to the rise in incidence of TB in central Europe to be expected over the coming years, it is essential to be acquainted with the radiological manifestations of pulmonary TB, particularly to be able to discriminate active from inactive TB. Due to the use of molecular techniques entailing DNA fingerprinting, the traditional classification of TB in primary and postprimary TB is being challenged. These genetic studies have revealed that variations in the clinical and radiographic appearance of TB are mainly affected by the immune status of the patients. Due to the low prevalence of TB in central Europe and the wide variation of radiological presentations, the diagnosis and therapy of TB is often delayed. In this article, the radiographic manifestations of thoracic TB are summarized and discussed.

Together with the medical history and bacteriological tests, chest X‑ray imaging and computed tomography (CT) play a major role not only in the detection of TB but also in the follow-up during and after therapy.

Chest X‑radiographs should be the primary diagnostic method in patients with suspected TB in screening as well as for diagnosis and therapy monitoring. The use of CT is more sensitive than chest radiographs and is frequently performed after chest radiographs to obtain detailed information about subtle parenchymal changes or lymph node manifestation. When active TB is suspected CT should be performed. Tree in bud, lobular consolidations, centrilobular nodules, cavities and ground-glass opacification are typical changes in active TB.