gms | German Medical Science

Objective: Neurovascular compression (NVC) is described as an impressive pathological conflict between cranial nerves and vasculature at the surface of the brainstem. With the application of high resolution MRI the individual neurovascular anatomy can be delineated in a three-dimensional fashion. The primary goal of this contribution was to realize the technical innovation of in-vivo ultra-fast real-time MRI in the visualization of pulsational characteristics of NVC at the medulla oblongata.

Methods: Real-time MRI of the neurovascular dynamics of the medulla oblongata was performed in a young hypertensive proband for the first-time. A 3 Tesla MRI scanner (Prisma, Siemens Healthineers) with an equipped multi-GPU system for real-time MRI was applied. Serial image reconstruction was achieved by calibration-less parallel imaging using nonlinear inversion. The reconstruction time per frame was lower than the acqusition time, so that image reconstruction was based on a convolution of the image with the point-spread function that can be implemented using a fast Fourier transform algorithm.

Results: We firstly performed a real-time MRI of the posterior fossa with the focus on neurovascular morphology and pulsational characteristics of the vertebral arteries. We were able to visualize the in-vivo pulsation of the vertebral arteries towards the ventrolateral medulla oblongata during diastole and systole. The pulsational pattern during heartbeat could be delineated with a narrow intravascular diameter during the diastolic phase and an enlarged intravascular diameter during the systolic phase. In the scanned proband a distinct cerebrospinal fluid layer between the adventitia of the vertebral artery and the pial surface of the lower brainstem could be differentiated.

Conclusion: An etiologic association of pulsatile neurovascular compression at the medulla oblongata with arterial hypertension is widely discussed and there are missing clear translational criteria in detailed patient selection for neurosurgical treatment. Our technique deals with the perspective application of real-time MRI for the in-vivo visualization of pathological neurovascular dynamics at the brainstem. We aim to establish novel imaging biomarkers based on state-of-the-art MRI methods.