Tuberculosis Screening

Purpose	Screen detection of tuberculosis on chest radiograph, in asymptomatic adults
Tag(s)
Panel	Thoracic
Define-AI ID	08190005
Originator	Eric J. Stern
Panel Chair	Eric J. Stern
Panel Reviewers	Thoracic Panel
License	Creative Commons 4.0
Status	Published
RadElement Set	RDES79

Clinical Implementation

Value Proposition

The value proposition is well stated by the World Health Organization publication: Chest radiography in tuberculosis detection – summary of current WHO recommendations and guidance on programmatic approaches:

“Systematic screening for active pulmonary TB is defined as the “systematic identification of people with suspected active TB in a predetermined target group, using tests, examinations or other procedures that can be applied rapidly”. Unlike the evaluation of those who actively seek care for respiratory symptoms (see Tuberculosis, Triage), the systematic screening of individuals for TB is typically initiated by a provider and offered in a systematic way to an apparently healthy target group that has been determined to have a high risk of TB.

Systematic screening outside health facilities – such as in the community or in special institutions such as prisons or shelters for homeless people – is often labelled active case finding, which refers to a provider initiated approach that actively reaches outside the health services. Such screening can help find prevalent cases of TB in the community that might otherwise go undiagnosed and untreated. It often requires screening a large number of people who do not have TB. Costs can be high, and the risk of a false positive diagnosis is high when TB prevalence in the screened group is low or moderate (4). Therefore, choosing an accurate screening algorithm is critical, and there are specific considerations involved, including how well the screening and diagnostic tools perform in the population to be screened, the tradeoff between risks and benefits to the person being screened, the ability of the screening algorithms to detect TB without risking overdiagnosis, and the feasibility and costs.” [1]

The chest radiography (CXR) has high sensitivity for pulmonary TB and thus is a valuable tool to identify TB as a differential diagnosis for patients, especially when the radiograph is interpreted to identify any abnormality that is consistent with TB. However, many CXR abnormalities that are consistent with pulmonary TB are seen also in several other lung diseases, often with significant intra- and interobserver variation in interpretations, which can lead to both overdiagnosis and underdiagnosis.

Narrative(s)

In the specific context of a TB prevalence survey to determine the population prevalence of TB, screening is applied to identify individuals who should undergo bacteriological examinations. CXR is the most sensitive screening tool for identifying those survey participants with a high probability of having TB. For diagnosis, combining CXR and symptom checklists for screening (with, typically, a positive result in either category being sufficient to warrant further testing) with culture or an alternative bacteriological test with high sensitivity (such as the Xpert MTB/RIF assay), will generate the most accurate prevalence estimate for bacteriologically positive TB (the objective of a TB prevalence survey). CXR should, therefore, be used for all participants in a survey, regardless of their symptoms or risk markers.

Workflow Description

Image obtained from modality and sent to PACS (or mini-PACS) and the AI engine. Image analyzed by engine. System detects and characterizes exam for suspected tuberculosis. An alert message is sent to PACS from the engine with the information, and identification, and graphic highlighting abnormalities. Cases in which AI has detected active TB are flagged and prioritized for expedited reading in worklist.

Considerations for Dataset Development

Procedures(s):	XRAY, Chest
View(s):	primarily AP, PA only, PA/Lat (supplementary Apical Lordotic or decubitus views)
Sex at Birth:	MFemale
History:	asyale, mptomatic
Comorbidities:	pleural fluid (including air/fluid levels), other lung disease (eg. bullous emphysema, malignancy, left-sided congestive heart failure, pulmonary edema, prior chest surgery, prior lung injury)
Lung Tissue Involvement:	right, left, bilateral
Distribution:	upper, middle, lower, diffuse, segmental or lobar cavitary, micronodular, nodular, calcifications, linear scarring

Technical Specifications

Inputs

DICOM Study

Procedure	XRAY, Chest
Views	PA, AP, PA/Lat, apical lordotic, lateral decubitus
Data Type	DICOM
Modality	XRAY
Body Region	Chest
Anatomic Focus	Lung
Pharmaceutical	N/A
Scenario	N/A

 

Primary Outputs

Tuberculosis Detection

RadElement ID	RDE385
Definition	Detection of tuberculosis in symptomatic adult patient
Data Type	Categorical
Value Set	0-Unknown 1-Tuberculosis present 2-Tuberculosis absent
Units	N/A

 

Future Development Ideas

Subgroups of interest, including people living with HIV and different age groups

• improving triaging

• improving the clinical diagnosis of TB

• improving the diagnosis of childhood TB

• implementing systematic screening in risk groups

• scaling up detection and treatment of latent TB infection

References

1. Chest radiography in tuberculosis detection – summary of current WHO recommendations and guidance on programmatic approaches. I. World Health Organization. ISBN 978 92 4 151150 6