Chest radiography and tuberculosis case-finding in Western Australia

Area of Science:

• Public Health
• Radiology
• Infectious Disease Epidemiology

Background:

• Tuberculosis (TB) control strategies evolve with changing disease prevalence.
• Chest radiography (CR) has historically played a role in TB detection and management.
• Assessing the long-term effectiveness of CR in TB control is crucial for public health policy.

Purpose of the Study:

• To evaluate the historical role and current utility of chest radiography in tuberculosis control in Western Australia.
• To determine the yield of active TB cases detected through mass and selective CR screening programs.
• To assess the contribution of CR to TB case-finding in a low-prevalence environment.

Main Methods:

• Retrospective review of annual reports (1948-1983) and Perth Chest Clinic (PCC) records (1992-1993).
• Analysis of mass miniature radiography (MMR) yield and contribution to total TB notifications over different periods.
• Examination of CR findings in asymptomatic individuals undergoing screening for various reasons.

Main Results:

• Selective MMR (1948-1951) yielded 3.3 TB cases/1000 films (18.3% of notifications).
• Compulsory statewide screening (1952-1972) yielded 0.7 TB cases/1000 films (19.6% of notifications).
• Selective screening (1977-1979) yielded 0.2 TB cases/1000 films (2.7% of notifications).
• In 1992-1993, CR detected active TB in 0.2% of asymptomatic individuals (2.4 cases/1000 films, 10% of notifications).

Conclusions:

• Mass CR, when selectively applied, significantly contributes to TB case-finding.
• CR remains a valuable tool for TB detection, even in low-prevalence countries aiming for elimination.
• The yield of CR screening is influenced by the prevalence of TB in the screened population.