In patients with chronic thromboembolic pulmonary hypertension (CTEPH), lung perfused blood volume (PBV) and mean pulmonary artery (PA) enhancement could be indicators of hemodynamics, according to the results of a retrospective analysis using dual-energy computed tomography published in the Journal of Computer Assisted Tomography.

Investigators sought to evaluate the link between dual-energy computed tomography (CT) quantitative parameters and hemodynamics in patients with CTEPH. Between April 2014 and July 2017, a total of 58 consecutive patients who had undergone dual-energy CT for a detailed examination or follow-up of their CTEPH received treatment at Nagoya University Hospital in Japan. A CTEPH diagnosis was confirmed with the use of ventilation/perfusion scintigraphy, right heart catheterization (RHC), and pulmonary arteriography.

Of the 58 consecutive patients, 6 were excluded from the study for a variety of reasons, leaving a total of 52 remaining patients to be assessed retrospectively. Of these 52 patients, 20 were men and 32 were women. The median participant age was 65.5 years. Dual-energy CT and RHC were performed within 6 months of each other. The participants’ lung PBV and mean PA enhancement, which were measured at the pulmonary parenchymal phase, were compared with hemodynamics.

Correlations were demonstrated between dual-energy CT parameters and body weight with RHC hemodynamics. Mean lung PBV was significantly correlated with mean pulmonary arterial pressure (mPAP; Spearman rank correlation coefficient [rs]=0.47; 95% CI, 0.23-0.66; P <.001), systolic ventricular pressure (rs=0.44; 95% CI, 0.19-0.63; P =.001), right arterial pressure (rs=0.32; 95% CI, 0.05-0.54; P=.022), and pulmonary vascular resistance (rs=0.31; 95% CI, 0.04-0.53; P =.027)

In addition, whole lung PBV was significantly correlated with mPAP (P =.010); however the correlation coefficient was lower than that for lung PBV calculated when excluding the upper right zone. Furthermore, PA enhancement was significantly associated with cardiac index (P <.001) and with pulmonary vascular resistance (P <.001). The area under the curve (AUC) was 0.86 for lung PBV to predict mPAP >50 mm Hg. The AUC was also 0.86 for PA enhancement to predict pulmonary vascular resistance >1000 dyne·s/cm5.

The investigators concluded that the study findings showed the ability of the quantitative values of lung PBV and PA enhancement to identify patients with severe CTEPH. Thus, lung PBV and PA enhancement could be used as indicators of hemodynamics, with noninvasive quantitative dual-energy CT parameters helping to guide the management of patients with CTEPH.

Reference

Tsutsumi Y, Iwano S, Okumura N, et al. Assessment of severity in chronic thromboembolic pulmonary hypertension by quantitative parameters of dual-energy computed tomography. J Comput Assist Tomogr. 2020;44(4):578-585.