Pegah Entezari MD, Presenter: Nothing to Disclose

Susanne Schnell, Abstract Co-Author: Nothing to Disclose

Naomi C. Chesler PhD, Abstract Co-Author: Nothing to Disclose

Christopher Jean-Pierre Francois MD, Abstract Co-Author: Nothing to Disclose

Alejandro Roldan PhD, Abstract Co-Author: Nothing to Disclose

Oliver Wieben PhD, Abstract Co-Author: Nothing to Disclose

Jeremy Douglas Collins MD, Abstract Co-Author: Consultant, C. R. Bard, Inc

James Christopher Carr MD, Abstract Co-Author: Speaker, Lantheus Medical Imaging, Inc

Alex Barker, Abstract Co-Author: Nothing to Disclose

Michael Markl PhD, Abstract Co-Author: Nothing to Disclose

To evaluate peak velocity, net flow, vessel diameter and wall shear stress (WSS) in the proximal pulmonary arteries of normotensive controls and patients with pulmonary arterial hypertension (PAH) using 4D flow MRI.

With IRB approval, 10 patients (age: 57±10, 5 females) and 9 volunteers (age: 40 ±12, 6 females) were scanned on a 3T MR system. Time-resolved 3D pulmonary flow was measured using 4DMRI with full coverage of the right ventricular outflow tract, pulmonary trunk (PT) and right and left pulmonary branches (RPA and LPA). Net flow and maximum velocity were quantified at the level of PT, RPA and LPA. WSS and vessel diameter were also measured in analysis planes positioned at these three levels in both groups.

Net flow in PAH patients (PT: 52.7±11, LPA: 21.5±5, RPA: 26.2±7 ml/cycle) was significantly lower compared to controls (PT: 68.3±13, LPA: 29.3±7, RPA: 32.7±5 ml/cycle, p-value< 0.05). The same pattern was observed for peak velocity in PAH patients (PT: 0.5±0.1, LPA: 0.3±0.1, RPA: 0.4±0.1 m/s) compared to the controls (PT: 0.8±0.1, LPA: 0.7±0.2, RPA: 0.9±0.2 m/s, p-value< 0.05). In addition, PAH arteries had a significantly larger diameter (PT: 3.4±0.5, LPA: 2.3±0.3, RPA: 2.4±0.3 cm) compared to the normal population (PT: 2.6±0.2, LPA: 1.8±0.2, RPA: 1.7±0.3 cm, p-value< 0.001). As shown in Figure 1, PAH patients had reduced WSS at all three measurement positions, compared to volunteers.

4D flow MRI illustrates distinct hemodynamic changes in PAH patients compared to a normal population. The significant reduction in net flow, peak velocity and an increase in PA lumen diameter in patients resulted in decreased WSS values, as compared to normal volunteers.

Pulmonary hypertension is associated with right heart failure, but its effect on arterial diameter and hemodynamic factors (i.e. velocity, flow, WSS) and their role in disease progression is not clear

Entezari, P, Schnell, S, Chesler, N, Francois, C, Roldan, A, Wieben, O, Collins, J, Carr, J, Barker, A, Markl, M, Role of 4D Flow MRI in Detecting Hemodynamic Changes in Patients with Pulmonary Arterial Hypertension.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13016229.html