Seyed Mohammad Mehdi Ameli Renani MBBS, Presenter: Nothing to Disclose

Farzana Mehzabin Rahman FRCR, MBBS, Abstract Co-Author: Nothing to Disclose

Laurie Ramsay BMBCh, Abstract Co-Author: Nothing to Disclose

Arjun Nair MBBCh, FRCR, Abstract Co-Author: Nothing to Disclose

Brendan P. A. Madden MBBCh, MD, Abstract Co-Author: Nothing to Disclose

Ioannis Vlahos MRCP, FRCR, Abstract Co-Author: Consultant, Siemens AG Consultant, General Electric Company

Veronica Smith MBBCh, MRCP, Abstract Co-Author: Nothing to Disclose

Kate Baskerville, Abstract Co-Author: Nothing to Disclose

Anand Devaraj MBBS, Abstract Co-Author: Nothing to Disclose

To evaluate quantitative differences in central pulmonary artery (PA), and pulmonary global and regional enhancement in patients with and without PH using DECT material differentiation analysis of central vascular arterial enhancement and PBV.

From 391 thoracic DECT studies (2 yrs), 89 patients (46 males) were identified with PA pressure data and CT pulmonary angiogram study (100/Sn140kVp, refmAs 150/128, 100 mls 5ml/s iohexol 300mgI/ml, Definition FLASH, Siemens). PH was defined as mean pulmonary artery pressure (mPAP) >25mmHg at right heart catheter (RHC) (n=19) or >45mmHg at echocardiography (n=20). PH absence was defined by entirely normal echocardiography or RHC mPAP<20mmHg (n= 50). PA enhancement (PAe) was calculated from DECT iodine images. Volumetric enhancement of the whole lung (WLe) and of 6 standard lung regions (RLe), as well as of 24 2-D standardized regions of interest (ROIe) was performed in each patient using PBV analysis (Syngo Via,-960 to -300HU threshold). PAe was compared to PBV enhancement and variance in patients with and without PH (Mann-Whitney U). Correlations to pulmonary vascular resistance (PVR) were calculated from RHC data (Pearson’s).

PAe was greater in PH patients (mean 277 v 252HU, p=0.05), however, this group had a reciprocal reduction in pulmonary parenchymal enhancement (mean WLe 27 v 32HU, p<0.01). Individual ROIe (n=2058) confirmed lower PBV in PH (mean 27 v 36HU, p<0.001) with larger ROIe measurement standard deviation (mean 10.3 v 9.5, p<0.001).  PH pulmonary enhancement variability was confirmed by greater mean intra-patient variance of the 6 RLe (37 v 22HU, p=0.02) and 24 ROIe measures (188 v 130HU, p=0.04). Variance of RLe and ROIe correlated with PVR (r=0.44, 0.45, p=0.04, 0.03 respectively) and persisted even when pulmonary embolic disease was excluded (p=0.02, p=0.03).  A ratio of PAe/WLe distinguished PH from non-PH patients (mean 10.9 v 8.5, p<0.001) and correlated well with PVR (r=0.59, p=0.004).

PH patients demonstrate increased PA enhancement with a reciprocal reduction and greater variation of parenchymal enhancement; a DECT ratio of central to parenchymal enhancement correlates with PVR and may help identify PH.

DECT enables the quantifiable demonstration of increased PA and reduced parenchymal enhancement in PH; this new CT observation appears correlated physiologically to PVR and may be a new marker of PH.

Ameli Renani, S, Rahman, F, Ramsay, L, Nair, A, Madden, B, Vlahos, I, Smith, V, Baskerville, K, Devaraj, A, Insights into Pulmonary Hypertension (PH) Pulmonary Blood Flow Dynamics Using Dual Energy CT (DECT) and Pulmonary Blood Volume Imaging (PBV).  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12031054.html