# Relevance of the correlation between tomography findings and laboratory test results in the accuracy of the diagnosis of pulmonary tuberculosis

## TL;DR

This study shows that CT scans and lab tests together improve the accuracy of diagnosing pulmonary tuberculosis.

## Contribution

The study identifies specific CT patterns correlated with lab results in diagnosing pulmonary tuberculosis.

## Key findings

- Small nodules and tree-in-bud patterns on CT scans were more common in confirmed tuberculosis cases.
- CT findings like septal thickening and lymph node enlargement correlated with positive lab results.
- CT scans showed high predictive values for diagnosing PTB, especially when lab results were inconclusive.

## Abstract

To evaluate the correlation between multidetector computed tomography (MDCT)
findings and laboratory test results in patients with pulmonary tuberculosis
(PTB).

A total of 57 patients were evaluated. Patients with suspected PTB were
divided into groups according to the final diagnosis (confirmed or
excluded), and the groups were compared in terms of sociodemographic
variables, clinical symptoms, tomography findings, and laboratory test
results.

Among the patients with a confirmed diagnosis of PTB, small pulmonary nodules
with a peribronchovascular distribution were significantly more common in
the patients with a positive sputum smear microscopy result (47.4% vs. 8.3%;
p = 0.046), as were a miliary pattern (36.8% vs. 0.0%;
p = 0.026), septal thickening (84.2% vs. 41.7%;
p = 0.021), and lymph node enlargement (52.6% vs. 8.3%;
p = 0.020). Small pulmonary nodules with a
centrilobular distribution were significantly more common among the
culture-positive patients (75.0% vs. 35.7%; p = 0.045), as
was a tree-in-bud pattern (91.7% vs. 42.9%; p = 0.014). A
tree-in-bud pattern, one of the main tomography findings characteristic of
PTB, had a sensitivity, specificity, positive predictive value, and negative
predictive value of 71.0%, 73.1%, 75.9%, and 67.9%, respectively.

MDCT presented reliable predictive values for the main tomography findings in
the diagnosis of PTB, being a safe tool for the diagnosis of PTB in patients
with clinical suspicion of the disease. It also appears to be a suitable
tool for the selection of patients who are candidates for more complex,
invasive examinations from among those with high clinical suspicion of PTB
and a negative sputum smear microscopy result.