Noninvasive Measurement of Intra-Aneurysmal Pressure and Flow Pattern Using Phase Contrast with Vastly Undersampled Isotropic Projection Imaging

Moftakhar, Roham; Aagaard-Kienitz, B.; Johnson, Kevin M.; Turski, Patrick A.; Turk, Aquilla S; Niemann, David; Consigny, Daniel W.; Grinde, J.; Wieben, Oliver; Mistretta, Charles A.

doi:10.3174/ajnr.a0648

Cited by 52 publications

(36 citation statements)

References 24 publications

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“…PC-VIPR, a novel 3D MR imaging sequence with potentially better spatial resolution and shorter imaging times than conventional 3D PCMRA, has shown good in vivo and in vitro correlations with 2D cine PCMR flow measurements (correlation coefficient ϭ 0.97). 42 Additionally, several reports have studied the use of this technique to examine pressure gradients across experimental stenosis, 39,43,44 but not blood flow velocities or volumetric flow. Our experiment represents the first in vivo study incorporating stenosis to create a range of blood flows to assess the accuracy of volumetric flow measurements by using PCMR.…”

Section: Discussionmentioning

confidence: 99%

In Vivo Evaluation of Quantitative MR Angiography in a Canine Carotid Artery Stenosis Model

Calderon-Arnulphi¹,

Amin‐Hanjani²,

Alaraj³

et al. 2011

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE: Large-vessel cerebral blood flow quantification has emerged as a potential predictor of stroke risk. QMRA uses phase-contrast techniques to noninvasively measure vessel flows. To evaluate the in vivo accuracy of QMRA for measuring the effects of progressive arterial stenosis, we compared this technique with invasive flow measurements from a sonographic transit-time flow probe in a canine model.

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Section: Discussionmentioning

confidence: 99%

In Vivo Evaluation of Quantitative MR Angiography in a Canine Carotid Artery Stenosis Model

Calderon-Arnulphi¹,

Amin‐Hanjani²,

Alaraj³

et al. 2011

AJNR Am J Neuroradiol

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“…To obtain information on the real blood flow in cerebral aneurysms, phase-contrast magnetic resonance imaging (PC MRI) is effective since it enables us to obtain three-dimensional (3D) unsteady blood flow velocity vectors in the target blood vessels. 10,15 In addition, based on the velocity data measured with PC MRI, a calculation algorithm of the pressure field in the blood vessel has been proposed by Moftakhar et al 18 However, the time and spatial resolutions of the PC MRI are inferior to those of ultrasonic measurement and X-ray computed tomography (CT). Especially, the measurement accuracy for low velocity areas, where regurgitation occurs or which are close to the blood vessel, is still insufficient since PC MRI requires a velocity encoding value (VENC).…”

Section: Introductionmentioning

confidence: 99%

Numerical Validation of MR-Measurement-Integrated Simulation of Blood Flow in a Cerebral Aneurysm

et al. 2009

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This study proposes magnetic resonance (MR)-measurement-integrated (MR-MI) simulation, in which the difference between the computed velocity field and the phase-contrast MRI measurement data is fed back to the numerical simulation. The computational accuracy and the fundamental characteristics, such as steady characteristics and transient characteristics, of the MR-MI simulation were investigated by a numerical experiment. We dealt with reproduction of three-dimensional steady and unsteady blood flow fields in a realistic cerebral aneurysm developed at a bifurcation. The MR-MI simulation reduced the error derived from the incorrect boundary conditions in the blood flow in the cerebral aneurysm. For the reproduction of steady and unsteady standard solutions, the error of velocity decreased to 13% and to 22% in one cardiac cycle, respectively, compared with the ordinary simulation without feedback. Moreover, the application of feedback shortened the computational convergence, and thus the convergent solution and periodic solution were obtained within less computational time in the MR-MI simulation than that in the ordinary simulation. The dividing flow ratio toward the two outlets after bifurcation was well estimated owing to the improvement of computational accuracy. Furthermore, the MR-MI simulation yielded wall shear stress distribution on the cerebral aneurysm of the standard solution accurately and in detail.

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“…Previous studies have demonstrated good results for the assessment of pressure gradients in aneurysms ( 22 ) and TSPG ( 16 ) with phase-contrast VIPR in other vascular territories. However, the previous iterations of this technique were limited in their ability to assess vessels in areas complicated by respiratory motion ( 16 ).…”

Section: Discussionmentioning

confidence: 99%

Noninvasive Assessment of Transstenotic Pressure Gradients in Porcine Renal Artery Stenoses by Using Vastly Undersampled Phase-Contrast MR Angiography

Bley¹,

Johnson²,

François³

et al. 2011

Radiology

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Purpose:To compare noninvasive transstenotic pressure gradient (TSPG) measurements derived from high -spatial-and temporal-resolution four-dimensional magnetic resonance (MR) fl ow measurements with invasive measurements obtained from endovascular pressure wires with digital subtraction angiographic guidance. Materials and Methods:After Animal Care and Use Committee approval, bilateral renal artery stenosis (RAS) was created surgically in 12 swine. Respiratory-gated phase-contrast vastly undersampled isotropic projection (VIPR) MR angiography of the renal arteries was performed with a 1.5-T clinical MR system (repetition time, 11.4 msec; echo time [fi rst echo], 3.7 msec; 18 000 projection angles; imaging volume, 260 3 260 3 200 mm; acquired isotropic spatial resolution, 1.0 3 1.0 3 1.0 mm; velocity encoding , 150 cm/sec). Velocities measured with phase-contrast VIPR were used to calculate TSPGs by using Navier-Stokes equations. These were compared with endovascular pressure measurements (mean and peak) performed by using fl uoroscopic guidance with regression analysis. Results:In 19 renal arteries with an average stenosis of 62% (range, 0%-87%), there was excellent correlation between the noninvasive TSPG measurement with phase-contrast VIPR and invasive TSPG measurement for mean TSPG ( R 2 = 95 .4%) and strong correlation between noninvasive TSPG and invasive TSPG for the peak TSPG measures ( R 2 = 82.6%). The phase-contrast VIPR-derived TSPG measures were slightly lower than the endovascular measurements. In four arteries with severe stenoses and one occlusion (mean, 86%; range, 75%-100%), the residual lumen within the stenosis was too small to determine TSPG with phasecontrast VIPR. Conclusion:The unenhanced MR angiographic technique with phasecontrast VIPR allows for accurate noninvasive assessment of hemodynamic signifi cance in a porcine model of RAS with highly accurate TSPG measurements.

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Noninvasive Measurement of Intra-Aneurysmal Pressure and Flow Pattern Using Phase Contrast with Vastly Undersampled Isotropic Projection Imaging

Cited by 52 publications

References 24 publications

In Vivo Evaluation of Quantitative MR Angiography in a Canine Carotid Artery Stenosis Model

In Vivo Evaluation of Quantitative MR Angiography in a Canine Carotid Artery Stenosis Model

Numerical Validation of MR-Measurement-Integrated Simulation of Blood Flow in a Cerebral Aneurysm

Noninvasive Assessment of Transstenotic Pressure Gradients in Porcine Renal Artery Stenoses by Using Vastly Undersampled Phase-Contrast MR Angiography

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