Role of HRCT in Sputum Smear Negative Patients of Suspected Pulmonary Tuberculosis

Abstract

Objective: To determine the role of HRCT in suspected Pulmonary TB patients, who were
otherwise sputum smear negative for AFB.
Methods: The study comprised of 100 patients of both sexes of 16-60 years of age group. It was
a cross sectional study and Convenience and non probability sampling was done Patients who
were having sputum negative for AFB in three consecutive samples but suspected to have active
PTB from clinical features and chest X ray findings were included in the study. Study was
conducted in Institute of TB and Chest Medicine KEMU/Mayo hospital Lahore.

Results: On HRCT, 52% had tree in bud appearance,42% had ill-defined soft tissue nodules
(both small and large), randomly distributed nodules 16%, 34% had ill-defined infiltrates 25% had
consolidation,21% had cavitations and 18% had peri bronchial wall thickening. Chi square
analysis showed a strong positive correlation between final diagnosis and HRCT with sensitivity
of diagnosing active PTB was 91%,Specificity 54%,PPV 68% and NPV 92%.
Conclusions: HRCT is a useful, powerful and reliable tool in distinction of active pulmonary TB
and so it can be used even before bronchial washings results are available.