3D amplified MRI (aMRI)

Abstract

Purpose Amplified MRI (aMRI) has been introduced as a new method of detecting and visualizing pulsatile brain motion in 2D. Here, we improve aMRI by introducing a novel 3D aMRI approach. Methods 3D aMRI was developed and tested for its ability to amplify sub‐voxel motion in all three directions. In addition, 3D aMRI was qualitatively compared to 2D aMRI on multi‐slice and 3D (volumetric) balanced steady‐state free precession cine data and phase contrast (PC‐MRI) acquired on healthy volunteers at 3T. Optical flow maps and 4D animations were produced from volumetric 3D aMRI data. Results 3D aMRI exhibits better image quality and fewer motion artifacts compared to 2D aMRI. The tissue motion was seen to match that of PC‐MRI, with the predominant brain tissue displacement occurring in the cranial‐caudal direction. Optical flow maps capture the brain tissue motion and display the physical change in shape of the ventricles by the relative movement of the surrounding tissues. The 4D animations show the complete brain tissue and cerebrospinal fluid (CSF) motion, helping to highlight the “piston‐like” motion of the ventricles. Conclusions Here, we introduce a novel 3D aMRI approach that enables one to visualize amplified cardiac‐ and CSF‐induced brain motion in striking detail. 3D aMRI captures brain motion with better image quality than 2D aMRI and supports a larger amplification factor. The optical flow maps and 4D animations of 3D aMRI may open up exciting applications for neurological diseases that affect the biomechanics of the brain and brain fluids.

Review of the Midbrain Ascending Arousal Network Nuclei and Implications for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), Gulf War Illness (GWI) and Postexertional Malaise (PEM)

“…It is difficult to map the embryological and anatomical nuclei to (x,y,z) MRI coordinates such as Montreal Neurological Institute (MNI) because of the extensive flexion of the neural tube that generates the wedge-shaped midbrain with wide dorsal and narrow ventral surfaces, and angulation of the brainstem at the base of the skull. The challenge is increased given the degree of motion of the brainstem with each heartbeat [ 30 , 31 , 51 , 52 ]. However, the results generate the hypothesis that different nuclei are differentially activated during the working memory tasks and are altered by exercise [ 25 ].…”

“…We proposed that affected nuclei may participate in the pathology of postexertional malaise based on the profound influences of these nuclei on threat assessment, pain, negative emotion, attention, wakefulness, and instinctual neurobehaviours. Evaluation of midbrain and brainstem was supported by exercise-induced autonomic dysfunction [ 28 , 29 , 30 , 31 ] and worsening of dizziness and lightheadedness in ME/CFS [ 29 ] as well as magnetic resonance imaging findings of brainstem atrophy in GWI [ 32 , 33 ] and dysfunction in ME/CFS [ 34 , 35 , 36 ].…”

An Anti‐Biofouling Flexible Fiber Biofuel Cell Working in the Brain

“…As shown in Figure 2f, the maximal power density of fiber BFC maintained over 92% during the period. As for implantable applications, it is known that the brain tissue in the living body bears constant micromovements due to respiration and heartbeat, [ 43 ] which raises the requirement for implantable electronics to perform stably under repeated deformations. The mechanical stability of fiber BFC performance was monitored by performing LSVs after every 25 cycles of bending at 30°.…”

Differential Effects of Exercise on fMRI of the Midbrain Ascending Arousal Network Nuclei in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Gulf War Illness (GWI) in a Model of Postexertional Malaise (PEM)

“…Therefore, we consider the results to be a general predictor of changes in BOLD for nuclei in the ascending arousal network that are congruent with the dorsal midbrain region of interest found in our previous study [ 14 ]. The results do suggest that significant differences will be found in future studies that specifically target these nuclei in ME/CFS and GWI when suitable sample sizes are compared and advanced motion correction algorithms are applied [ 73 , 74 , 75 , 76 ]. The most significant differences were induced by exercise with elevated BOLD in ME/CFS subjects but reductions in the GWI group, and were most clearly exposed by a comparison of ME/CFS vs. GWI groups rather than differences from control subjects ( Table 5 and Table S19 ).…”