Detection of right ventricular myocardial fibrosis using quantitative CT attenuation of the right ventricular myocardium in the late phase on 320 slice CT in subjects with pulmonary hypertension

Purpose: Right ventricular myocardial (RVM) fibrosis may be a significant indicator of prognosis in pulmonary hypertension (PH). To detect the presence of RVM fibrosis in PH subjects, we employed ECG gated 320-slice CT. Methods: 62 confirmed PH subjects (16 males; 55 +/- 16 years; 45 chronic thromboembolic PH (CTEPH) who underwent conventional non-surgical medical therapy; and 17 pulmonary arterial hypertension (PAH)) underwent ECG-gated 320-slice CT. On CT, RV fibrosis was defined as contrast defect in the early phase and conversely abnormal enhancement in the late phase. Results: RVM fibrosis was observed in 14 subjects (23%) on CT (CTEPH 22%; PAH 29%; P = 0.91). CT attenuation of RVM in the late phasewas significantly greater in subjectswith RVM fibrosis than in thosewithout (P= 0.025). ROC curves of CT attenuation of RVM in the early and late phase, and ratio of CT attenuation of RVM in the early phase/late phase showed AUCs of 0.55, 0.70, and 0.65, respectively. The best cutoff points of 79.5 HU (sensitivity of 50% and specificity of 69% for CT attenuation of RVM in the early phase, P= 0.59), 99.5 HU (sensitivity of 50% and specificity of 88% for CT attenuation of RVM in the late phase, P = 0.025), and 1.416 (sensitivity of 29% and specificity of 94% for ratio of CT attenuation of RVM in the early phase/late phase, P = 0.092) were used to distinguish subjects +/- RVM fibrosis. Conclusion: Quantitative-measurement of CT attenuation of RVMin the late phasemay be able to detect presence of RVM fibrosis in PH subjects. (C) 2016 Elsevier Ireland Ltd. All rights reserved.