Zur Pulsation des Liquor cerebrospinalis

Abstract

ZusammenfassungHintergrund: Das neuroanatomische Wissen über die Liquorräume und aus der Schädel-Hirn-Traumatologie offenbare Phänomene wie das Pulsieren des Gehirns bei bestehendem Kreislauf sind seit dem Altertum bekannt. Die Geschichte der Entdeckung des Liquors und dessen Flusses ist jedoch relativ jung. Seit Einführung von Pneumenzephalographie und Myelographie, von nuklearmedizinischen Techniken und insbesondere mit der Entwicklung der Kernspintomographie ist die Kenntnis der Liquordynamik fortgeschritten. Bildgebende Darstellung: Die langsame Komponente der Liquorbewegung, die Durchmischung und Verteilung von Substanzen im Liquor können szintigraphisch und myelographisch gezeigt werden. Die schnelle Komponente der Liquorbewegung, die Pulsation des Liquors mit dem Herzschlag und der Atmung, ist kernspintomographisch am besten darstellbar und quantifizierbar. Die Bewegung im intrakraniellen und spinalen Subarachnoidalraum sowie die Bewegung des Gehirns und des Myelons selbst können durch geschwindigkeitskodierte Sequenzen sichtbar gemacht werden. In der Regel werden EKG-getriggerte Phasenkontrast-, aber auch Spinecho-oder InversionRecovery-Sequenzen verwendet. Pathophysiologie: Der Hauptmotor der Liquorbewegung ist der arterielle Bluteinstrom ins Gehirn. Die konsekutive Ausdehnung der Gefäße auf der Hirnoberfläche, des Gehirns selbst und in geringerem Umfang des Plexus choroideus führt zu einem Liquorausstrom aus dem Schädelinneren, dessen Dynamik beschrieben wird. Die Pulsationsbewegung setzt sich in den Spinalkanal fort. Dort sind neben der Propulsion von kranial weitere Einflüsse auf die Liquorbewegung wie die Ausdehnung des Epiduralraums anzunehmen. Schlussfolgerung: Da die Kernspintomographie arteriellen und venösen Fluss sowie auch die Bewegung des Liquors messen kann, kann sie einen Beitrag zur Darstellung und Erklärung pathologischer Veränderungen leisten. So ist bei der Entstehung eines Normaldruckhydrozephalus die Störung der Liquordynamik ein maßgeblicher Faktor. Schlüsselwörter: MR-Tomographie · Liquor · LiquordynamikBackground: Neuroanatomical knowledge about the cerebrospinal spaces and phenomena like pulsation of the brain after fractures of the skull have been known in ancient times. However, the history of the discovery of the cerebrospinal fluid (CSF) and of its flow phenomena is relatively new. Due to the introduction of the techniques of pneumencephalography, myelography and nuclear medicine, as well as especially the development of MR tomography this knowledge has improved. Imaging: The slow component of cerebrospinal fluid movement, the mixture and distribution of substances in the cerebrospinal fluid, can be delineated scintigraphically and by myelography. The fast component which is the pulsation of cerebrospinal fluid according to the cardiac cycle and respiration can be measured by MR tomography. The movement in the intracranial and intraspinal cerebrospinal fluid spaces and the movement of the brain and myelon itself can be shown by velocity-encoded sequences. As a rule ECG-trigger...

Computational investigation of subject-specific cerebrospinal fluid flow in the third ventricle and aqueduct of Sylvius

“…The former observation indicates that the feethead motion of the third ventricle walls is only marginally responsible for the pulsatile motion of CSF. The latter appears to be counterintuitive at first, but can be explained if one bears in mind that only feet-head motion has been taken into account: as the brain moves upwards during diastole (Friese et al, 2002), its caudal parts are displaced farther than the cranial ones, causing the third ventricle to be compressed in feet-head direction. At the same time, however, the brain also moves outwards, causing the third ventricle walls to bulge out.…”

Quantitative magnetic resonance spectroscopy in the entire human cervical spinal cord and beyond at 3T

“…Additional CSF flow compensation using techniques such as respiratory gating, navigator gating, and volume tracking (34–37) is most likely a prerequisite for the general extension of spinal cord MRS to the thoracic spinal cord. Shim convergence improves again in the lumbar spinal cord, where CSF flow is significantly decreased in comparison to cervical and thoracic spinal cord, while the flow pattern is more complex (15). Examples of interpretable MRS data in the conus medullaris and in patients with large intramedullary lesions in the lumbar region occluding the spinal canal have been reported by Dydak et al (7) and by Kim et al (8).…”

“…Thus, T 1 ‐ and B 1 ‐insensitive suppression of unwanted signal to below 3% of its original intensity was achieved. The maximum duration of each saturation pulse was 6 ms. To account for pulsatile CSF flow, which amounts up to 1 cm per cardiac cycle in the cervical spine (15), OVS slabs were not only placed anterior‐posterior and right‐left of the spectroscopy voxel but also along the head‐feet direction. PPR pulses achieve bandwidths of 38.2 kHz, 12.3 kHz, or 6.2 kHz for flip angles of 30°, 90°, and 150°, respectively, for a maximum B 1 field strength of 13.5 μT (body coil—compare “experimental setup”).…”

Computational Investigation on CSF Flow Analysis in the Third Ventricle and Aqueduct of Sylvius

“…We assumed that the both sides of the Foramen of Monro possess the same flow rate. A normal uniform flow rates inlets were designate at various flow rate to resembles normal and hydrocephalus conditions.0.1166 ml/s (0.7 ml/min) was regarded as normal flow rate based on the Friese [2] findings and the others parameter was referred to Linninger [4]. Based on the shown graph, as the CSF flow reach at aqueduct of Sylvius at nearly 0.025m from the Foramen of Monro and flow through along it at approximately 0.01 m, we can see a sharp pressure drop indicating that the narrow channel of the aqueduct does the effect to the flow characteristic.…”

“…They communicate by way of the foramen of Monro with the third ventricle located in the median sagittal plane of the cerebrum. The fourth ventricle is connected to the third through the aqueduct of Sylvius .CSF is secreted from the bloodstream mainly in the choroid plexi of the brain ventricles at a rate of approximately 0.7 ml/min [2].A pulsatile motion, governed primarily by the cardiac cycle, is superimposed upon the steady flow caused by the CSF production; the interaction between the cardiovascular and the CSF systems is not fully understood. Traditionally, it was accepted that the CSF is drained mainly through the arachnoid villus system in the superior sagittal sinus.…”