{'fraction_non_alphanumeric': 0.0258751902587519, 'fraction_numerical': 0.0136986301369863, 'mean_word_length': 4.870535714285714, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Computed Tomographic Assessment of the Posterior Junction Line and Its Association With Emphysema

Background: Visualization of a posterior junction line (PJL) on chest x-ray is evidence for emphysema. The correlation between the assessment of the PJL on computed tomography (CT) and emphysema is less clear. Methods: One hundred thirty-seven patients were identified with CT and pulmonary function tests (PFTs) performed within 3 months of each other in a University hospital. The width of the PJL was measured at 2 levels by a blinded investigator: superiorly at the superior border of the aorta and inferiorly 2 cm below the aortic arch. This was correlated to clinical and PFT data and to CT evidence of emphysema. Results: Narrowness of the junction line showed poor correlation with PFT findings of emphysema as assessed by forced expiratory volume in 1 second-forced vital capacity ratio and diffusing capacity of the lung for carbon monoxide percent predicted. The PJL also correlated weakly to CT emphysema severity scoring (r2 = 0.06; P < 0.002). The area under the receiver operator characteristic curve was 0.652, with maximum accuracy at a width of 1.3 cm. Conclusions: Our data suggest that despite statistical correlation between the narrowness of the PJL and emphysema, its clinical use is limited.