From the Guidelines
The right infrahilar region on a chest X-ray is a critical area to evaluate for signs of pulmonary hypertension (PH), such as enlargement of the central pulmonary arteries, with or without rapid tapering (pruning), and right heart chamber enlargement, as identified in the study by Miniati et al 1. When examining this region, radiologists look for abnormalities such as masses, infiltrates, consolidation, or lymphadenopathy, which may indicate conditions like pneumonia, tuberculosis, lung cancer, or lymphoma. The right infrahilar region is particularly important because pathology here can sometimes be obscured by the heart shadow on the left side, making right-sided findings more visible. Key findings of PH on CXR include:
- Enlargement of the central pulmonary arteries
- Right heart chamber enlargement
- A measurement of the right interlobar artery >15 mm in women (>16 mm in men) at the hilum, which is suggestive of PH, as noted in the study 1. When interpreting findings in this region, it's essential to compare with previous imaging if available and correlate with clinical symptoms, such as dyspnea or risk factors for PH, as recommended in the study by Schmidt et al, referenced in 1. The density and appearance of this region should be compared to the corresponding area on the left side, as asymmetry may indicate pathology. Normal anatomical structures in this area include the lower lobe bronchi and pulmonary vessels, which appear as branching linear opacities extending from the hilum toward the periphery of the lung. In patients with suspected PH, a normal CXR does not exclude PH, and further imaging evaluation should be pursued if there are persistent unexplained symptoms, as stated in the study 1.
From the Research
Right Infrahilar Region on Chest X-ray
There are no research papers to assist in answering this question, as the provided studies do not mention the right infrahilar region on chest X-ray.
- The studies focus on the treatment of tuberculosis, including the pharmacokinetics of antituberculosis drugs 2, treatment regimens for isoniazid-resistant tuberculosis 3, and updates in the treatment of active and latent tuberculosis 4, 5.
- One study discusses the efficacy and safety of a combined isoniazid-rifampicin-pyrazinamide-levofloxacin dry powder inhaler in the treatment of pulmonary tuberculosis, but does not mention the right infrahilar region on chest X-ray 6.
- None of the studies provide information on the diagnosis or interpretation of chest X-rays, including the right infrahilar region.