CT patterns of nodal disease in pediatric chest tuberculosis

To highlight various patterns of nodal involvement and post treatment changes in pediatric chest tuberculosis based on contrast enhanced computed tomography (CECT) scans of chest.

This was a retrospective study consisting of 91 patients aged less than 17 years, who attended Paediatrics OPD of All India Institute of Medical Sciences with clinically diagnosed tuberculosis or with chest radiographs suggestive of chest tuberculosis. These patients had an initial chest radiograph as well as CECT of the chest and follow up imaging after 6 mo, and in some cases 9 mo, of completion of anti-tubercular treatment (ATT). CECT of these patients was reviewed for the location and extent of nodal involvement along with determination of site, size, enhancement pattern and calcification.

Enlargement of mediastinal or hilar lymph nodes was found in 88/91 patients (96.7%), with the most common locations being paratracheal (84.1%), and subcarinal (76.1%). The most common pattern of enhancement was found to be inhomogenous. The nodes were conglomerate in 56.8% and discrete in 43.2%. In addition, perinodal fat was obscured in 84.1% of patients. In the post-treatment scan, there was 87.4% reduction in the size of the nodes. All nodes post-treatment were discrete and homogenous with perinodal fat present. Calcification was found both pre- and post-treatment, but there was an increase in incidence after treatment (41.7%). There was hence a reduction in size, change in enhancement pattern, and appearance of perinodal fat with treatment.

Tubercular nodes have varied appearance and enhancement pattern. Conglomeration and obscuration of perinodal fat suggest activity. In residual nodes decision to continue ATT requires clinical correlation.