Diagnosis of pulmonary arterial hypertension and pulmonary embolism with magnetic resonance angiography

Background: Pulmonary magnetic resonance angiography (PMRA) has been proven to be accurate for the diagnosis of suspected acute or chronic pulmonary embolism (PE). Only limited data exist on the reliability of PMRA for the diagnosis of acute and chronic pulmonary artery hypertension (PAH). The aim of this study was to determine the accuracy of PMRA in the differentiation between patients suffering from PAH of varying etiologies. Methods: Fifty patients (21 women; mean [+/- SD] age, 52 +/- 16 years) were examined with gadolinium-enhanced PMRA for the evaluation of pulmonary artery (PA) disease. The diagnosis of PAH (ie, systolic PA pressure of >35 mm Hg) was determined by Doppler echocardiography. The criteria for the diagnosis of chronic PAH by PMRA were dilated central PAS (diameter >28 mm) and abnormal proximal-to-distal tapering of the PAS. The diagnostic criterion for acute and chronic PE was the presence of an intravascular filling defect. Results: Chronic PAH was present in 18 patients, which was correctly identified by PMRA in 16 patients (sensitivity, 89%). All patients without PAH had normal findings on PMRA (specificity, 100%). Only 1 of 18 patients with normal findings on PMRA showed moderate chronic PAH (negative predictive value, 94%). PAH due to acute/subacute pulmonary thromboembolism (15 patients) was identified in all patients (sensitivity, 100%). Acute PAR was differentiated from chronic PAH in all cases by the detection of intravascular filling defects and the lack of abnormal proximal-to-distal tapering of PAS. Conclusions: PMRA is a promising noninvasive imaging modality for the identification of patients with acute or chronic PAH. This technique should be considered a sensitive and highly specific screening tool for suspected chronic PAH.