Roentgen examination is the only method available for detecting early pulmonary tuberculosis. A few years ago such a statement would have been considered a heresy, but with the improvement in the technic of the use of x-rays and the taking of serial films it is now recognized that the early lesions of pulmonary tuberculosis are frequently deep seated and discrete.
McPhedran1 considers tubercle deposits which are found by roentgen examination as "latent" when there are no physical signs or symptoms that can be noted by the physician or patient, and adds that "there can be no sharp line of demarcation between latent and manifest disease."
When râles can be heard in a lung or, as a rule, when hemoptysis or pleurisy or cough has occurred, lesions of pulmonary tuberculosis are advanced.
The early lesions of tuberculosis discovered by roentgen examination are not usually accompanied by marked symptoms of disease.
WEBB GB. THE EARLY DIAGNOSIS AND EARLY CARE OF PULMONARY TUBERCULOSIS. JAMA. 1929;92(22):1811-1813. doi:10.1001/jama.1929.02700480001001