Noninvasive assessment of transstenotic pressure gradients in porcine renal artery stenoses by using vastly undersampled phase-contrast MR angiography.

PURPOSE To compare noninvasive transstenotic pressure gradient (TSPG) measurements derived from high-spatial- and temporal-resolution four-dimensional magnetic resonance (MR) flow 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 [first echo], 3.7 msec; 18,000 projection angles; imaging volume, 260 × 260 × 200 mm; acquired isotropic spatial resolution, 1.0 × 1.0 × 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 fluoroscopic 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 (R² = 95.4%) and strong correlation between noninvasive TSPG and invasive TSPG for the peak TSPG measures (R² = 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 phase-contrast VIPR. CONCLUSION The unenhanced MR angiographic technique with phase-contrast VIPR allows for accurate noninvasive assessment of hemodynamic significance in a porcine model of RAS with highly accurate TSPG measurements.

[1]  T. Grist,et al.  Time‐resolved 3D MR angiography of the abdomen with a real‐time system , 2004, Magnetic resonance in medicine.

[2]  N. Ives,et al.  Angioplasty and STent for Renal Artery Lesions (ASTRAL trial): rationale, methods and results so far , 2007, Journal of Human Hypertension.

[3]  G. Sarno,et al.  Assessment of renal artery stenosis: side-by-side comparison of angiography and duplex ultrasound with pressure gradient measurements. , 2008, European heart journal.

[4]  J. Tijssen,et al.  Magnetic resonance angiography for the diagnosis of renal artery stenosis: a meta-analysis. , 2002, Clinical radiology.

[5]  F P Cappuccio,et al.  Renal artery stenosis: a common and important problem in patients with peripheral vascular disease. , 1994, The American journal of medicine.

[6]  M. Bettmann,et al.  Guidelines for the Reporting of Renal Artery Revascularization in Clinical Trials , 2002, Journal of vascular and interventional radiology : JVIR.

[7]  O Wieben,et al.  Noninvasive Measurement of Intra-Aneurysmal Pressure and Flow Pattern Using Phase Contrast with Vastly Undersampled Isotropic Projection Imaging , 2007, American Journal of Neuroradiology.

[8]  B. Wranne,et al.  Temporally resolved 3D phase‐contrast imaging , 1996, Magnetic resonance in medicine.

[9]  T. Lehnert,et al.  Treatment of ostial renal-artery stenoses with vascular endoprostheses after unsuccessful balloon angioplasty. , 1997, The New England journal of medicine.

[10]  Ganesh Manoharan,et al.  Assessment of renal artery stenosis severity by pressure gradient measurements. , 2006, Journal of the American College of Cardiology.

[11]  J. Carrozza,et al.  Physiologic evaluation of translesion pressure gradients in peripheral arteries: comparison of pressure wire and catheter-derived measurements. , 2007, Journal of interventional cardiology.

[12]  J Waigand,et al.  Determination of renal arterial stenosis severity: comparison of pressure gradient and vessel diameter. , 2001, Radiology.

[13]  Richard B Thompson,et al.  Fast measurement of intracardiac pressure differences with 2D breath‐hold phase‐contrast MRI , 2003, Magnetic resonance in medicine.

[14]  P. Krijnen,et al.  The effect of balloon angioplasty on hypertension in atherosclerotic renal-artery stenosis. Dutch Renal Artery Stenosis Intervention Cooperative Study Group. , 2000, The New England journal of medicine.

[15]  E. Krishnamurthy,et al.  Magnetic resonance angiography , 1995, Proceedings of the First Regional Conference, IEEE Engineering in Medicine and Biology Society and 14th Conference of the Biomedical Engineering Society of India. An International Meet.

[16]  D. Leung,et al.  Magnetic resonance angiography versus duplex sonography for diagnosing renovascular disease. , 1999, Hypertension.

[17]  C Mistretta,et al.  Physiologic and anatomic assessment of a canine carotid artery stenosis model utilizing phase contrast with vastly undersampled isotropic projection imaging. , 2007, AJNR. American journal of neuroradiology.

[18]  Noah J. Jones,et al.  Usefulness of translesional pressure gradient and pharmacological provocation for the assessment of intermediate renal artery disease , 2006, Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions.

[19]  C. Cooper,et al.  Utility of a 0.014″ pressure‐sensing guidewire to assess renal artery translesional systolic pressure gradients , 2003, Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions.

[20]  Charles A Mistretta,et al.  Transstenotic pressure gradients: measurement in swine--retrospectively ECG-gated 3D phase-contrast MR angiography versus endovascular pressure-sensing guidewires. , 2007, Radiology.

[21]  F. Korosec,et al.  PC VIPR: a high-speed 3D phase-contrast method for flow quantification and high-resolution angiography. , 2005, AJNR. American journal of neuroradiology.

[22]  D. Laidlaw,et al.  Three‐dimensional, time‐resolved (4D) relative pressure mapping using magnetic resonance imaging , 2000, Journal of magnetic resonance imaging : JMRI.

[23]  Patrick A Turski,et al.  Improved 3D phase contrast MRI with off‐resonance corrected dual echo VIPR , 2008, Magnetic resonance in medicine.

[24]  G. Moneta,et al.  Duplex ultrasound scanning in the diagnosis of renal artery stenosis: a prospective evaluation. , 1988, Journal of vascular surgery.

[25]  U. Mödder,et al.  Renovascular disease: a review of diagnostic and therapeutic procedures. , 2006, Minerva urologica e nefrologica = The Italian journal of urology and nephrology.

[26]  J M Bland,et al.  Statistical methods for assessing agreement between two methods of clinical measurement , 1986 .

[27]  J. V. van Engelshoven,et al.  Motion of the distal renal artery during three‐dimensional contrast‐enhanced breath‐hold MRA , 2002, Journal of magnetic resonance imaging : JMRI.