Gert Reiter, Presenter: Employee, Siemens AG

Ursula Reiter, Abstract Co-Author: Nothing to Disclose

Gabor Kovacs MD, Abstract Co-Author: Nothing to Disclose

Horst Olschewski MD, Abstract Co-Author: Nothing to Disclose

Michael Herbert Fuchsjaeger MD, Abstract Co-Author: Nothing to Disclose

To establish a relationship between mean pulmonary arterial pressure (mPAP) and period of existence of vortical blood flow in the main pulmonary artery derived from magnetic resonance phase-contrast imaging (MR-PCI) to 1) evaluate accuracy of non-invasive vortex-based estimation of mPAP and 2) define cut-off values for the diagnosis of manifest pulmonary hypertension (PH).

The prospective study was approved by the local ethical review board. 145 patients with suspected PH (69 patients with and 76 without manifest PH) underwent right heart catheterization (RHC) and ECG-gated, time resolved three-dimensional MR-PCI of the main pulmonary artery. Velocity fields derived from MR-PCI were visualized with dedicated software and evaluated for period of existence of vortical blood flow (tvortex in percent of the cardiac interval) in the main pulmonary artery. Relationship between mPAP and tvortex was analyzed by means of regression, Bland-Altman and receiver operating characteristic curve analysis.

Relationship between mPAP and tvortex was excellently (goodness-of-the-fit parameter R2 = 0.95) described as increasing linearly from tvortex = 0% (mPAP ≤ 16 mmHg) with a slope of 1.6% per mmHg. Employing this relation to estimate elevated mPAP from tvortex in patients with manifest PH resulted in a standard deviation of 4 mmHg between MR-PCI vortex-based and RHC-derived mPAP values. Manifest PH, defined as mPAP ≥ 25 mmHg, corresponded to tvortex ≥ 14% of cardiac interval. Area under the curve was 0.99 (95% confidence interval 0.98-1.00) for tvortex-based diagnosis of manifest PH. Applying the cut-off value tvortex ≥ 14% resulted in a sensitivity of 0.97 (95% confidence interval 0.90-0.99) and a specificity of 0.96 (95% confidence interval 0.89-0.99) for diagnosis of manifest PH.  

MR-PCI based determination of periods of existence of vortical blood flow in main pulmonary artery allows for both, accurate diagnosis of PH and accurate estimation of elevated mPAP.

Vortex based assessment of mPAP has the potential to become the non-invasive, non-ionizing method of choice for early recognition and longitudinal follow up of patients with PH.

Reiter, G, Reiter, U, Kovacs, G, Olschewski, H, Fuchsjaeger, M, Assessment of Mean Pulmonary Arterial Pressure and Diagnosis of Pulmonary Hypertension Based on Vertical Blood Flow in the Main Pulmonary Artery.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13024436.html