Revolutionising Tuberculosis Diagnosis: Role Of Radiology In TB Detection
The key to TB control is conducting large scale public screening programs to detect those individuals who have TB without being aware of this and are spreading TB to other members of the community
According to the World Economic Forum, India has more than 27 per cent of the world's burden of tuberculosis (TB). The economic costs incurred translate to USD 300 million in lost wages per year, and a USD 23 billion indirect cost to the Indian economy due to lost productivity. Control of TB can therefore clearly result in significant benefits to the Indian economy.
It is unfortunate that of the eight countries that account for more than two-thirds of the global total of tuberculosis cases, India is one (others include Nigeria, Bangladesh and the Democratic Republic of Congo).
This is at odds with our country’s global image of a progressive and technologically advanced nation that is focused on its citizens' health and well-being. However, this can be reversed using a combination of modern medicine and public health determination. This is centered around the effective use of radiology, which is a key tool in the diagnosis and management of tuberculosis.
X-ray is primarily used to identify TB, given that it is the least expensive and most widely available imaging modality. TB typically initially affects the lungs, hence the term pulmonary TB. X-rays can show changes in the lungs associated with TB, including cavity formation, thickening of the pleura that coats the lung, enlargement of lymph nodes and calcium deposits.
The key to TB control is conducting large scale public screening programs to detect those individuals who have TB without being aware of this and are spreading TB to other members of the community. Identification of such individuals followed by temporary isolation and treatment forms the keystone of TB control.
In such programs, the use of X-ray is critical in detecting subclinical TB. These patients are a public health hazard as they are spreading the disease to healthy people without knowing that they have the infection.
By conducting screening camps in endemic areas such as crowded living communities, early TB diagnosis can be made and patients can be isolated to prevent the spread of infection within the community.
For this however, the screening program has to be done on a mass scale which results in a large number of radiographs that need to be interpreted. Currently, there is a shortage of radiologists to report such large numbers of radiographs and therefore the use of teleradiology is particularly important.
Teleradiology works by bringing the images to the location of the radiologist, thereby making the radiologist more efficient and allowing for optimal utilization of the radiologist’s time. Using a mobile van setup coupled with teleradiology can allow for the transfer of the images to a centralized reporting facility where an expert radiologist can report these x-rays in a standardized manner for better documentation.
Combining the use of artificial intelligence algorithms into this workflow can further assist in the screening and detection of TB at an early stage. Artificial intelligence algorithms are trained to detect the abnormalities characteristic of tuberculosis as described above.
CT scans can further help to identify subtle changes not seen on X-rays and can help to differentiate TB from other lung diseases. CT scans are also useful for determining the extent of the infection and how far it has spread.
CT and ultrasound scans are also helpful in diagnosing the abdominal spread of tuberculosis which is not uncommon in patients in India who have advanced infection. Abdominal ultrasound can detect some of the features of abdominal tuberculosis such as peritoneal fluid and enlarged lymph nodes.
Finally, MRI scans can help to identify changes associated with TB that are not seen on CT scans. MRI is particularly helpful in the depiction of TB of the spine and its complications which can include paralysis if the disease progresses and remains untreated.
Radiology can also be used to monitor the progress of TB treatment. If lung opacities, cavities or lymph nodes are becoming less visible on imaging tests, this indicates that the patient is improving.
In summary, Radiology is key for both the early detection, diagnosis and subsequent management of TB. While X-ray combined with Teleradiology and AI forms the basis for screening and early detection, computed tomography (CT) and MRI scans can be used to evaluate for progression and spread of the disease within the body as well as check the response to treatment.
Early detection of TB as well as its effective treatment can both result in benefits to the Indian economy by restricting the impact of this chronically debilitating and eminently curable disease on our citizens’ health.