World Tuberculosis Day: The Role of PET/CT Diagnostic Imaging in Tuberculosis
World Tuberculosis Day: The Role of PET/CT Diagnostic Imaging in Tuberculosis
Every year on 24th of March, it is a timely reminder that tuberculosis (TB) remains a global public health priority. This is a date chosen to commemorate the 1882 announcement by Dr Robert Koch that he had identified Mycobacterium tuberculosis, the bacterium responsible for TB.
According to the World Health Organisation (WHO), approximately 10.8 million people fell ill with TB globally in 2024, affecting 1.2 million lives globally. This makes TB the world's second leading infectious disease killer after COVID-19. In addition, drug-resistant TB continues to pose a mounting challenge, with over 400,000 new cases of multidrug-resistant TB (MDR-TB) detected annually.
The good news is that with the right tools and early detection, it is both treatable and preventable.
The Diagnostic Challenge
When a patient has an unusual lung lesion one of the most clinically pressing questions remains to be answered: — is this cancer, infection, or inflammation. Both TB and lung cancer can produce:
•Pulmonary nodules (small masses in the lung)
•Enlarged lymph nodes in the chest
•Areas of consolidation on imaging
On a standard CT scan, these findings can appear nearly identical. For clinicians, that uncertainty has real consequences and for the patients, it means waiting, worrying, and potentially delayed treatment
How PET/CT Overcomes this Challenge
PET/CT (Positron Emission Tomography / Computed Tomography) is a hybrid technology that combines anatomical detail (CT) with metabolic activity (PET). 18F-FDG is a radioactive glucose tracer that is widely used in PET/CT which is taken up by cells with high metabolic activity, such as cancer cells and active infection sites. This gives clinicians a far richer picture than CT alone.
In general pulmonary assessment, PET/CT plays a pivotal role in:
•Characterising lung nodules:Sensitivity exceeding 90% in identifying metabolically active malignant nodules, helping guide biopsy decisions.
•Lymph node staging:Detecting nodal involvement more accurately than CT alone, directly influencing surgical eligibility.
•Monitoring treatment response:In both TB therapy and lung cancer chemotherapy, PET/CT detects metabolic changes weeks before visible anatomical changes.
•Whole-body disease mapping:In one session, it can image the full extent of disseminated TB or metastatic cancer
An Important Honesty Check
The 18F-FDG uptake is not specific to infection or inflammation and can also be elevated in malignancies. In clinical practice, this means TB can mimic malignancy on PET/CT, which might result in a diagnostic pitfall. The FDG PET/CT is generally considered a complementary method to conventional imaging and is not typically the first-line imaging modality for these conditions.
At Positron Diagnostics, every report is produced by experienced nuclear physicians who interpret findings alongside the patient's medical history, clinical context and other diagnostic information.
Know the Risk Factors for TB
•Close contact with a known TB case
•A history of travel to or residence in high-burden countries
•Weakened immune system (HIV, diabetes, immunosuppressive therapy)
•Living or working in crowded conditions
•Healthcare workers with unprotected exposure
Symptoms to Watch Out For TB
TB symptoms are easy to dismiss as a lingering cold or fatigue, which is exactly why it so often goes undetected. See a doctor if you notice:
Persistent cough lasting more than three weeks
Coughing up blood or mucus
Unexplained weight loss or loss of appetite
Fever and night sweats
Persistent fatigue or feeling run-down
Chest pain or discomfort when breathing or coughing
These symptoms can overlap with other pulmonary conditions, which is why proper imaging and specialist assessment is really important.
Better Imaging Tools, Better Outcomes
Early diagnosis means earlier treatment, faster recovery, and a dramatically reduced chance of transmission.
For more information about pulmonary PET/CT indications, please contact us.