Digital Radiology Key Benefits Print

Digital X-ray with Computer Aided Detection for TB (CAD4TB) facilitates cost-effective active and passive case finding as well as TB prevalence surveys. dCXR/CAD has a high negative predictive value for pulmonary TB, is rapid (1 minute) and costs about 20% of one Xpert® test, depending on settings.

Patient friendly

Check for TB using digital X-ray will give patients access to fast, accurate and convenient TB screening, reducing their travel cost, waiting time and speeding up access to diagnosis and treatment. Intensified TB case finding using digital radiology will support the combat against TB in people living with HIV who often present with smear negative sputum. New technology X-ray allows for low dose exposure for patients, making it an appropriate tool also for TB prevalence surveys and systematic screening of high risk groups. In combination with molecular tests, the time to diagnose active TB can be shortened from 20-40 days to about 2.5 hours. Digital radiology can also be used to spot pre-clinical TB and can support the health system in general, through diagnostic imaging of also other body parts.

High digital image quality

Digital X-rays are instantly available on the diagnostic monitor with constant high quality. Software tools to zoom in or to add contrast to the digital image are available and enhance ease and accuracy of TB screening. Issues of poor readability and deterioration or loss of films are eliminated.

Low image cost

Films and developer are no longer needed, storage of images is done electronically and superior readability allow for a very low cost per image. Cost savings relative to analog systems using films in high throughput settings can exceed Euro 100.000 per year per system. Even at a low throughput of 50 images per day, digital images are more economic. The section on "Cost Saving" presents the calculation of savings for different settings. A customised cost calculation can be made on this page in just some seconds.

Instant image retrieval

Digital radiology systems using an integrated Picture Archiving and Communications System (PACS) can efficiently archive and retrieve large numbers of digital X-rays. This eliminates the high archiving cost of analog film based X-ray images. Using the universal Digital Imaging and Communications in Medicine (DICOM) format, the PACS attaches patient information to the right X-ray , eliminating the risk of “storing a film in the wrong envelope” and, enhancing patient safety.

Environmentally friendly

Digital X-ray is clean technology as chemical waste from film developing, that can cause serious environmental damage, is completely eliminated.

Remote diagnosis - teleradiology

If the X-ray image cannot be interpreted locally because no specific knowledge is available or the image is particularly difficult to interpret, it can be sent over the internet or even over a low bandwidth (mobile phone) connection to a centre where accurate reading can be done. The diagnosis can be sent back immediately and continues to be attached to the right digital Chest X-ray.

Computer Aided Diagnosis

The diagnostic software protocol CAD4TB allows for the automated recognition and quantification of abnormalities consistent with TB in a digital Chest X-rays. CAD4TB is already as accurate as the trained human reader as demonstrated in studies in The Gambia, Philippines and Tanzania. In order to support TB prevalence surveys and early case detection in risk groups, this diagnostic software is available for use in the field as a “second opinion” or to automate triage before Xpert MTB/RIF. Regular CAD software updates now become available as the diagnostic accuracy continues to improve. In case of prevalence surveys the CAD sensitivity can be pre-selected to reach highest levels, allowing radiologists to focus more time on reading abnormal images and decimating the risk of missing cases. Depending on the budget NTP's can select an abnormality threshold for Xpert eligibility. Zambart in Zambia put this threshold at > 60% CAD abnormality score resulting in a high predictive value (23%) for a positive Xpert MTB/RIF test; a CAD abnormality score of > 80% resulted in 44% positive Xpert MTB/RIF tests.