Renal artery stenosis: Extracting quantitative parameters with a mathematical model fitted to magnetic resonance blood flow data

Abstract

Purpose:To investigate the feasibility of quantitative parameter extraction from a mathematical model fitted to renal artery magnetic resonance flow data. Material and Methods:A total of 16 subjects, eight patients, and eight normal controls, were examined with cine phase-contrast velocity measurements, and blood flow data from the aorta and both renal arteries were extracted by means of contour detection. A mathematical model with eight parameters describing the time, duration, and amplitude of the systolic acceleration and the diastolic deceleration was fitted to the aorta and renal artery blood flow data from each subject. The curve fitting was evaluated with R 2 values. Statistical analysis was performed with unpaired Wilcoxon tests and stepwise logistic regression. Results:A total of three data sets out of 48 yielded R 2 values below 0.80 and were considered unreliable for parameter estimation. Basal flow was significantly, and systolic peak amplitude almost significantly, lower in stenotic arteries. Logistic regression indicated that two parameters describing basal flow and the duration of acceleration can accurately predict stenosis. Conclusion:The results suggest that it is technically feasible to fit a mathematical model to renal blood flow data, extracting quantitative parameters that may prove useful for quantification and diagnosis of renal artery stenosis.

Characterization of the time course of the superior mesenteric, abdominal aorta, internal carotid and vertebral arteries blood flow response to the oral glucose challenge test using magnetic resonance imaging

“…Waveform analysis of blood flow depends on downstream resistance causing alteration of the waveform, and changes in the parameters describing blood flow waveforms and disease have been found (e.g. renal artery flow in renal artery disease (Larsson et al 2008). Using the technique described by Larsson et al (2008), waveform analysis provided further quantitative information as to the likely source of the changes in the SMA and additional information not previously apparent within the AA.…”

“…renal artery flow in renal artery disease (Larsson et al 2008). Using the technique described by Larsson et al (2008), waveform analysis provided further quantitative information as to the likely source of the changes in the SMA and additional information not previously apparent within the AA. There are some drawbacks of the waveform analysis method chosen so these results must be viewed with care.…”

“…Examples of the blood flow results across a cardiac cycle of the SMA are shown in figure 1(a). To provide an objective measure of any changes in the shapes of these curves, the data were fitted in Excel (Microsoft, Seattle, USA) using a model proposed by Larsson et al (2008):…”

“…Table 1. The full description of each parameter a-h described by the mathematical model in equation ( 1) (Larsson et al 2008).…”

“…Figure 7. Graph illustrating the mathematical model results of SMA baseline (model parameter a)to the OCGT meal(Larsson et al 2008). The gap in data is due to the time necessary for ingestion of the OGCT meal.…”