Role of measuring pulmonary artery size in interstitial lung disease using CT to evaluate pulmonary hypertension

Aim: We aimed to determine how accurately various measures of the PA, as viewed on HRCT, predict right heart catheterisation (RHC)-confirmed pulmonary hypertension.Methods: The present study was conducted in the Department of Radiology and 500 patients were included in the study. Patients with a CT scan within 90 days of MRI and RHC were included. In order to meet inclusion criteria, a diagnostic quality CT pulmonary angiogram (CTPA) with a slice thickness of less than 5 mm was required.Results: We included 500 scans from 500 patients; 300 (60%) had RHC-confirmed pulmonary hypertension, with mPAP ⩾25 mmHg. Compared with the non-pulmonary hypertension group, the group with pulmonary hypertension had greater MPAD, RPAD, LPAD and PA: Ao in both respiratory cycles, whereas the PA angle was greater in the non-pulmonary hypertension group. In the subgroup with pulmonary hypertension, the median MPAD was 34.60 mm in inspiration and 34.65 mm in expiration, while in the non-pulmonary hypertension group, it was 30.00 mm in inspiration and 30.50 mm in expiration. For the cohort as a whole, the areas under the receiver operating characteristic curves (AUCs) for inspiratory MPAD and inspiratory PA: Ao (for RHC-confirmed pulmonary hypertension defined as Mpap ⩾25 mmHg) were 0.741 and 0.750, respectively. For the cohort as a whole, the cut-offs MPAD ⩾32.5 mm and PA: Ao ⩾0.94 yielded the most favourable diagnostic profiles. Conclusion: Findings on HRCT may assist in the diagnosis of RHC-confirmed pulmonary hypertension. MPAD ⩾29 mm had high sensitivity and PA: Ao ⩾1.0 had high specificity. Compared with the entire cohort, MPAD had greater sensitivity in ILD and PA: Ao had higher specificity in COPD.