A computed method for noninvasive MRI assessment of pulmonary arterial hypertension

Abstract

The present method enables the noninvasive assessment of mean pulmonary arterial pressure from magnetic resonance phase mapping by computing both physical and biophysical parameters. The physical parameters include the mean blood flow velocity over the cross-sectional area of the main pulmonary artery (MPA) at the systolic peak and the maximal systolic MPA cross-sectional area value, whereas the biophysical parameters are related to each patient, such as height, weight, and heart rate. These parameters have been measured in a series of 31 patients undergoing right-side heart catheterization, and the computed mean pulmonary arterial pressure value (Ppa(Comp)) has been compared with the mean pressure value obtained from catheterization (Ppa(Cat)) in each patient. A significant correlation was found that did not differ from the identity line Ppa(Comp) = Ppa(Cat) (r = 0.92). The mean and maximal absolute differences between Ppa(Comp) and Ppa(Cat) were 5.4 and 11.9 mmHg, respectively. The method was also applied to compute the MPA systolic and diastolic pressures in the same patient series. We conclude that this computed method, which combines physical (whoever the patient) and biophysical parameters (related to each patient), improves the accuracy of MRI to noninvasively estimate pulmonary arterial pressures.

Magnetic Resonance–Derived 3-Dimensional Blood Flow Patterns in the Main Pulmonary Artery as a Marker of Pulmonary Hypertension and a Measure of Elevated Mean Pulmonary Arterial Pressure

“…25,26 This fact explains the reduced acceleration time in patients with manifest PH, which is the rationale for attempts to assess mPAP and PH directly by noninvasive methods. 2,3,[7][8][9][10][11] We also observed reduced acceleration times in patients with manifest PH.…”

“…Parameters that directly correlate with mPAP or pulmonary vascular resistance have been related to the shortened acceleration times of blood flow in the right ventricular outflow tract. 2,3,[7][8][9][10][11] However, the overall applicability and accuracy of the above-described methods are controversial. [12][13][14][15][16] Additionally, various authors 10,11,17,18 have observed spatially highly inhomogeneous cross-sectional flow profiles and fractions of retrograde flow during systole and diastole in the main pulmonary artery in patients with PH.…”

Magnetic Resonance Imaging in Pediatric Pulmonary Hypertension

“…That study also documented that, among PH patients, the time to achieve peak PA velocity was reduced and the velocity increase gradient was steeper. 13 Laffon and associates 14 developed a computerized algorithm for estimating mean PA pressure on the basis of an MRI evaluation of such physical values as PA crosssectional area and blood-flow velocity. This algorithm was also adjusted for patient-specific biophysical values, including height, weight, and heart rate.…”

Cardiac magnetic resonance imaging in pulmonary arterial hypertension

“…Flow velocity can be assessed by encoding the CMRI signal and can be used to calculate phase volumetric flow, which can be further used to determine a range of parameters, including end-diastolic volume, end-systolic volume and stroke volume, cardiac output and ejection fraction. However, although CMRI is an excellent technique for the assessment of volumes and flows, it is less useful for estimating PAP [30,31]. CMRI has been used to assess systolic PAP [32] and PVR [33] but is not yet considered to be an accurate replacement for measurement performed by RHC.…”