FIGURE 1.
Dual‐venc 4D flow MRI and transcranial Doppler ultrasound workflow. 4D flow MRI workflow example shows: (a) the volume coverage of the dual‐venc 4D flow MRI data based on TOF MRI; (b) the dual‐venc flow raw data including magnitude images and velocity encoded phase images in x, y, and z directions; (c) preprocessed data after eddy current correction, noise filtering, and velocity anti‐aliasing; (d) visualization and quantification of data by (d1) visualization of streamlines; (d2) PC‐MRA vessel segmentation; (d3) extraction of centerlines; (d4) placement of 2D analysis planes and (d5) lumen segmentation and velocity profile on a 2D plane. Transcranial Doppler workflow example shows (e) insonation of the middle cerebral artery via the transtemporal window; (f) the Doppler signal of the middle cerebral artery with the color bar representing signal intensity; (G) the digitization of the Doppler signal by Fast Fourier transform displayed by Windaq software; and (h) the middle cerebral artery flow velocities over time. FOV = field of view; TOF = time‐of‐flight; TCD = transcranial Doppler; MCA = middle cerebral artery; RMCA = right middle cerebral artery; LMCA = left middle cerebral artery.