What type of imaging is primarily used to evaluate potential active tuberculosis after a positive PPD test?

The primary imaging modality used to evaluate potential active tuberculosis after a positive PPD test is X-ray. A chest X-ray is typically the first step in assessing for active pulmonary tuberculosis, as it can reveal characteristic signs of the disease, such as cavitary lesions, consolidations, or infiltrates.

X-rays are widely available, quick to perform, and provide a good initial overview of lung pathology. They are often used to rule out or confirm active TB when there are clinical symptoms or a positive tuberculin skin test result. The speed and efficiency of X-ray imaging make it particularly suitable for this evaluation in various clinical settings.

Other imaging modalities, such as CT scans, are more sensitive and can provide detailed views of the lungs but are not routinely used as the initial diagnostic tool for suspected tuberculosis due to higher costs and greater radiation exposure. Ultrasonography is not a standard imaging tool for evaluating pulmonary conditions, and MRI, while useful in certain diagnostic scenarios, is not typically used for pulmonary assessments in cases of suspected tuberculosis. Therefore, the chest X-ray remains the primary imaging choice in this context.