Novel Technique to Measure Pulse Wave Velocity in Brain Vessels Using a Fast Simultaneous Multi-Slice Excitation Magnetic Resonance Sequence

Figures

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  Figure 1. Conceptual diagram of SMS-K technique. (A) The reference SMS-K image with full K-space acquisition lines containing all information from both slices (3rd and 9th). (B) The 500 SMS-K measurements using keyhole acquisition and reconstruction technique. Because one measurement acquires three K-space center lines (red thick lines), a scan time of 48 ms is required. Note that repetition time (TR) is 16 ms. Other K-space information from the reference SMS-K data was used for the keyhole reconstruction (blue thin lines). A gray scale bar indicates the signal intensity. Abbreviations: SMS-K, simultaneous multi-slice keyhole technique; IFT, inverse Fourier transform.

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  Figure 2. Phantom images comparing the SMS-K image with the mean GRE image of two selected slices. (A) The 3D modeling image and the phantom image acquired with 3D TOF MRA. (B) GRE images and the mean image of the 3rd and 9th slices. (C) SMS-K image acquired simultaneously on the 3rd and 9th slices. Gray scale bars indicate the signal intensity. Abbreviations: 3D TOF MRA, 3-dimensional time-of-flight magnetic resonance angiography; GRE, gradient echo; SMS-K, simultaneous multi-slice keyhole technique; 3D, 3 dimensional.

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  Figure 3. Human images comparing the SMS-K image with the mean GRE image of two selected slices. (A) Maximum-intensity projection images for CCA and ICA acquired with 3D TOF MRA. (B) GRE images and the mean image of the 3rd and 9th slices. (C) SMS-K image acquired simultaneously on the 3rd and 9th slices. Red circles indicate the target vessels for further analysis. Gray scale bars indicate the signal intensity. Abbreviations: 3D TOF MRA, 3-dimensional time-of-flight magnetic resonance angiography; CCA, common carotid artery; GRE, gradient echo; ICA, internal carotid artery; Lt, left; Rt, right; SMS-K, simultaneous multi-slice keyhole technique.

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  Figure 4. Pulse waveforms of CCA and ICA. (A) CCA (red) and ICA (blue) pulse waveforms consisted of 500 measurements for 24 s using SMS-K technique. (B) The pulse waveforms (blue) for the section of 100 measurement and the interpolated waveforms (red) of CCA and ICA. (C) Average pulse waveforms. The mean transit time of 5 sections between CCA and ICA was presented. Abbreviations: CCA, common carotid artery; ICA, internal carotid artery; SMS-K, simultaneous multi-slice keyhole technique.