A Systemic Approach to Chest Radiographic Assessment in Mycobacterium tuberculosis-Infected Cynomolgus Macaques...

Area of Science:

• Veterinary Radiology
• Primate Research
• Infectious Disease Imaging

Background:

• Accurate tuberculosis (TB) diagnosis in cynomolgus macaques is crucial for research.
• Existing diagnostic methods may require refinement for improved sensitivity and specificity.
• Chest radiography (CXR) offers a non-invasive imaging modality for TB assessment.

Purpose of the Study:

• To develop and validate a numerical CXR scoring system for TB detection in cynomolgus macaques.
• To establish reference image intensity values from healthy macaques.
• To assess the system's accuracy in identifying active tuberculosis infection (ATBI).

Main Methods:

• Collected CXRs from 90 healthy cynomolgus macaques in dorsoventral and lateral views.
• Analyzed mean and maximum image intensity values, establishing sex- and age-specific cutoffs.
• Validated the system using MLIs on 18 naturally TB-infected macaques and compared results with Xpert MTB/RIF Ultra.
• Further evaluated MLIs for lesion localization and progression tracking.
• Compared the CXR-MLI system with expert radiologist interpretation in 8 exposed macaques.

Main Results:

• Maximum lateral image intensity (MLIs) cutoffs demonstrated 100% accuracy in identifying TB infection.
• MLIs successfully predicted TB lesion progression, predominantly in the dorsal cranial lung lobe (T1-T4).
• The CXR-MLI system showed 62.5% agreement with expert radiologist assessment in a separate cohort.

Conclusions:

• The developed CXR-MLI scoring system is a highly accurate tool for TB detection in cynomolgus macaques.
• MLIs can effectively monitor TB lesion development and localization.
• This CXR-MLI system serves as a valuable supplementary diagnostic tool in primate TB research.