P6.14 THE EFFECT OF TEMPORAL RESOLUTION ON MR ASSESSMENT OF PULSE WAVE VELOCITY

DOI

10.1016/j.artres.2013.10.195How to use a DOI?

Abstract

Objectives: PWV can be measured by velocity-encoded phase-contrast magnetic resonance imaging (PC-MR) in a single location. One method utilises the change in flow (ΔQ) divided by the change in area (ΔA) at the beginning of systole, when it is assumed that only forward running waves are present. However, the duration of a reflection free period is short (∼30ms) and therefore a high sampling frequency is required to interrogate this period. Most PC-MR is performed with a low TR of approximately 30–40ms. In this study, we compared PWV calculated using high TR (10ms) and simulated low TR (30ms).

Methods: High TR (10ms) PC-MR was performed in 20 volunteers in the ascending aorta. TR reduction to 30ms was simulated by filtering the flow and area waveforms using a zero-phase, low-pass, high-order Butterworth filter with normalized cut-off frequency of 0.33 in Matlab. PWV was calculated from the gradient of the flow-area line at the onset of ejection, corresponding to the first 3 points of the foot of the area curve.

Results: There was a significant difference (p<0.0004) between PWV calculated using high TR mean 3.89m/s (SD 1.31) compared with simulated low TR, mean 7.30m/s (SD 3.64), Figure A. The mean bias between methods was 3.4m/s with wide limits of agreement (Figure B).

Conclusion: PWV calculated using a single location method is significantly inflated when data is acquired at low TR, as simulated using low-pass filtering. This suggests that conventional PC-MR may produce erroneous results in clinical studies.

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TY  - JOUR
AU  - M.A. Quail
AU  - J.A. Steeden
AU  - A.M. Taylor
AU  - V. Muthurangu
PY  - 2013
DA  - 2013/11/11
TI  - P6.14 THE EFFECT OF TEMPORAL RESOLUTION ON MR ASSESSMENT OF PULSE WAVE VELOCITY
JO  - Artery Research
SP  - 157
EP  - 158
VL  - 7
IS  - 3-4
SN  - 1876-4401
UR  - https://doi.org/10.1016/j.artres.2013.10.195
DO  - 10.1016/j.artres.2013.10.195
ID  - Quail2013
ER  -