Nina Bar-Am MD, Presenter: Nothing to Disclose

Ilan Shelef MD, Abstract Co-Author: Nothing to Disclose

Philip Rosen PhD, Abstract Co-Author: Nothing to Disclose

galia karp MD, Abstract Co-Author: Nothing to Disclose

Arik Wolak MD, Abstract Co-Author: Nothing to Disclose

To evaluate the impact of high and low reduction factors on the accuracy of phase contrast imaging for the calculation of pulse wave velocity (PWV.

A total of 32 female volunteers (age 43 ± 14 years, 18 healthy, 5 Rheumatoid Arthritis and 9 Systemic Lupus Erythematosus patients) were enrolled in this study. CMRI was performed using a 1.5T scanner and included phase contrast images perpendicular to the flow of the ascending and descending aorta with reduction factors of 2 and 4. A dedicated cardiovascular analysis software package was used the measure the flow in the ascending and the descending aorta. The time that the flow wave took to propagate between the two points was analyzed from the flow curves by a step-wise temporal shift of the descending aorta flow curve until it coincided with the ascending aorta flow curve. The PWV was calculated by dividing the distance between the measurement positions in the ascending and descending aorta by the propagation time. Threshold of 6.5 m/s was considered to be normal. The results are expressed as mean± SD. Pearson's correlation coefficient (PCC), intra-class correlation (ICC) and Bland-Altman's analysis (BAA) were used to assess agreement. The McNemar test was used to assess a difference between proportions.

There was no significant difference between PWV-SF2 (SENSE factor 2) and PWV-SF4 (SENSE factor 4), 6.16 ±2.66 m/s vs. 5.95±2.4 m/s, respectively, p=NS. The PCC was 0.74, p<0.01. The ICC was 0.78 for single measures and 0.87 for average measures, p<0.01 for both measurements. The BAA showed a bias of -0.22 and the 95% limits of agreement were 3.6-3.1 m/s. There were no artifacts using the PWV-SF2 acquisition but 14 (43%) were noted using the PWV-SF4 acquisition. The rate of normal/abnormal values was 18/14 and 20/12 in the PWV-SF2 vs. PWV-SF4 groups, respectively, p=NS

In a mixed population of normal and collagen diseased female patients, PWV calculation at SF2 shows strong agreement with PWV calculation at SF4, in spite of a higher incidence of artifacts in the PWV-SF4 acquisition.

Hi sense factor study facilitated acquisition time without compromising diagnostic accuracy and is recommended for patients with breath holding difficulties

Bar-Am, N, Shelef, I, Rosen, P, karp, g, Wolak, A, Validation of Aortic Pulse Wave Velocity Analysis Assessed with Velocity-encoded MRI Using Parallel Imaging with High Reduction Factors.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12043723.html