Can MR Measurement of Renal Artery Flow and Renal Volume Predict the Outcome of Percutaneous Transluminal Renal Angioplasty?
- Department of Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zuerich (Switzerland)
- Department of Internal Medicine, Angiology Division, University Hospital Zurich, Raemistrasse 100, CH-8091 Zuerich (Switzerland)
- Department of Radiology, University Hospital Balgrist, Forchstrasse 340, CH-8008 Zuerich (Switzerland)
- Department of Radiology, University Hospital Essen, Hufelandstrasse 55, D-45122 Essen (Germany)
Purpose: Predicting therapeutic benefit from percutaneous transluminal renal angioplasty (PTRA) in patients with renal artery stenosis (RAS) remains difficult. This study investigates whether magnetic resonance (MR)-based renal artery flow measurements relative to renal parenchymal volume can predict clinical outcome following PTRA.Methods: The data on 23 patients (13 men, 10 women; age range 47-82 years, mean age 64 years) were analyzed. The indication for treatment was hypertension (n = 18) or renal insufficiency (n = 5). Thirty-four cases of RAS were identified: bilateral disease was manifest in 11 and unilateral disease in 12 patients. The MR imaging protocol included a breath-hold, cardiac-gated cine phase-contrast sequence for renal flow measurement and a fast multiplanar spoiled gradient-echo sequence for renal volume measurement. MR measurements were performed on the day prior to and the day following PTRA. Clinical success was defined as (a) a reduction in diastolic blood pressure > 15% or (b) a reduction in serum creatinine > 20%. Kidneys were categorized as normal volume or low volume. A renal flow index (RFI) was calculated by dividing the renal flow (ml/min) by the renal volume (cm{sup 3}).Results: Clinical success was observed in 11 patients. Twelve patients did not benefit from angioplasty. Normal kidney volume was seen in 10 of 11 responders and in 8 of 12 nonresponders, resulting in a sensitivity of 91%, specificity of 33%, a positive predictive value (PPV) of 56% and a negative predictive value (NPV) of 80%. A RFI below a threshold of 1.5 ml/min/cm{sup 3} predicted successful outcome with 100% sensitivity, 33% specificity, 58% PPV, and 100% NPV. The combination of normal renal volume and a RFI below 1.5 ml/min/cm{sup 3} identified PTRA responders with a sensitivity of 91%, a specificity of 67%, a PPV of 71%, and a NPV of 89%. PTRA resulted in a greater increase in renal flow in responders compared with nonresponders (p < 0.001).Conclusion: A combination of cine phase-contrast MR renal flow and parenchymal volume measurements enables identification of patients benefiting from PTRA with a high sensitivity and NPV, but only moderate specificity and PPV.
- OSTI ID:
- 21083516
- Journal Information:
- Cardiovascular and Interventional Radiology, Vol. 24, Issue 4; Other Information: DOI: 10.1007/s00270-001-0005-y; Copyright (c) 2001 Springer-Verlag New York Inc; Country of input: International Atomic Energy Agency (IAEA); ISSN 0174-1551
- Country of Publication:
- United States
- Language:
- English
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