Artificial intelligence can accurately detect signs of tuberculosis in chest X-rays, according to new research. 

The findings of a study in Denmark suggest that computer-aided diagnosis programmes are equally or more accurate than trained radiologists, and could be deployed in areas where there is a shortage of qualified staff. 

Tuberculosis (TB) remains the 13th leading cause of death globally, claiming around 1.6 million lives a year. 

After Covid, it is the second biggest infectious killer. 

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Chest X-rays can play an important role in diagnosing the disease, particularly among patients unable to produce good quality sputum samples for microbiological analysis. 

Scientists set about examining whether the use of computer-aided detection - or artificial intelligence (AI) software - could assist in analysing medical images areas where radiologists are in short supply. 

To date, there is a lack of good quality studies assessing AI's diagnostic accuracy.

The Herald:

The findings are being presented at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Copenhagen.

In research led by Dr Frauke Rudolf, an expert in infectious diseases at Aarhus University Hospital in Denmark, scientists compared the performance of qXr, a deep learning technology developed for automated chest X-ray readings, against two Ethiopian radiologists with different levels of experience.

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The AI programme was given mobile phone photographs of non-digital chest X-rays, to replicate the kind of scenario that would play out in parts of the world with comparatively low medical resources. 

Chest X-rays from 498 patients were analysed retrospectively. 

Of these, 57 had been diagnosed with TB - 16 as a result of PCR tests, and 41 by clinicians. 

In the case of the PCR-diagnosed cases, the AI software correctly identified 75% of the positive cases and was 85.7% accurate in returning a negative reading in the cases of patients who did not have TB. 

This compared to 62.5% and 91.7% respectively for the less experienced radiologist. 

The more experienced of the two radiologists was 75% accurate in identifying the PCR-positive cases, and 82% accurate in identifying the negative cases. 

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Diagnostic accuracy is split into two categories - sensitivity and specificity. 

The sensitivity of a test - or the person or programme interpreting scans - refers to the ability to correctly identify positive cases of the disease.

A highly sensitive rating means there are fewer false negatives - in other words, genuine cases being missed.

Specificity relates to the accuracy of identifying negative cases, meaning that there are fewer false positives.

This is important to ensuring that resources are not wasted on needless treatment and investigation that could also be harmful to a patient. 

The Herald:

Dr Rudolf said: “With an estimated three million undiagnosed patients in 2021, there is an urgent need to develop novel strategies and technologies aimed at improving TB detection in low-resource, high-incidence settings.

“We’ve shown that AI software is at least as good at detecting TB as a trained radiologist and that a simple mobile phone photograph is sufficient for analysis.

“In low resource areas with a high incidence of TB but a shortage of radiologists, chest X-rays could be photographed with a mobile phone and the image sent to be analysed remotely by the AI.

“This would allow more chest X-rays to be read properly and, crucially, allow more cases of TB to be diagnosed.”