Paratracheal Air Stripe Sign (PASS): A Useful Chest X-ray Finding for Diagnosis in Patients with Esophageal Achalasia

Introduction: Esophageal achalasia is a rare motility disorder, and esophagogastroduodenoscopy (EGD) alone has limited diagnostic accuracy, often leading to delayed diagnosis. High-resolution manometry (HRM) remains the diagnostic gold standard, but its availability in primary care is limited. Therefore, more accessible diagnostic methods are needed. Given the widespread use of chest X-ray, we investigated whether it reveals distinctive features in achalasia patients. Methods: In this retrospective cohort study, 215 patients with esophageal achalasia treated between 2015 and 2024 were analyzed. Diagnostic yields of EGD, esophagography, and computed tomography (CT) were evaluated among patients who underwent these examinations in primary care facilities. Chest X-rays were systematically reviewed for paratracheal radiolucency, and a novel radiographic sign—the Paratracheal Air Stripe Sign (PASS)—was defined as a paratracheal radiolucent area with a minimum width of ≥5 mm and length of ≥20 mm. To assess specificity, an additional analysis was performed in 210 patients with esophageal cancer as a non-achalasia control cohort. Results: Diagnostic yields in primary care were 41.4% for EGD, 88.4% for esophagography, and 34.8% for CT. PASS was present in 67.0% of achalasia cases and more frequent in patients with type I achalasia, sigmoid-type morphology, and advanced esophageal dilation. Among patients undiagnosed by EGD, 63.9% exhibited PASS. In the non-achalasia control cohort, PASS was observed in 18.0% of cases, predominantly in patients with structural esophageal changes such as tortuosity or dilatation. Conclusion: PASS represents a novel and clinically useful chest X-ray feature associated with esophageal achalasia. Its relatively high prevalence, even among cases missed by EGD, and low occurrence in non-achalasia patients suggest that routine assessment of PASS in chest X-rays may aid early detection and timely referral for definitive diagnosis, particularly in primary care settings.