Spinal cord motion and CSF flow in the cervical spine of 70 healthy participants

Abstract

Pulsatile spinal cord and CSF velocities related to the cardiac cycle can be depicted by phase‐contrast MRI. Among patients with spontaneous intracranial hypotension, we have recently described relevant differences compared with healthy controls in segment C2/C3. The method might be a promising tool to solve clinical and diagnostic ambiguities. Therefore, it is important to understand the physiological range and the effects of clinical and anatomical parameters in healthy volunteers. Within a prospective study, 3D T2‐weighted MRI for spinal canal anatomy and cardiac‐gated phase‐contrast MRI adapted to CSF flow and spinal cord motion for time‐resolved velocity data and derivatives were performed in 70 participants (age 20–79 years) in segments C2/C3 and C5/C6. Correlations were analyzed by multiple linear regression models; p < 0.01 was required to assume a significant impact of clinical or anatomical data quantified by the regression coefficient B. Data showed that in C2/C3, the CSF and spinal cord craniocaudal velocity ranges were 4.5 ± 0.9 and 0.55 ± 0.15 cm/s; the total displacements were 1.1 ± 0.3 and 0.07 ± 0.02 cm, respectively. The craniocaudal range of the CSF flow rate was 8.6 ± 2.4 mL/s; the CSF stroke volume was 2.1 ± 0.7 mL. In C5/C5, physiological narrowing of the spinal canal caused higher CSF velocity ranges and lower stroke volume (C5/C6 B = +1.64 cm/s, p < 0.001; B = −0.4 mL, p = 0.002, respectively). Aging correlated to lower spinal cord motion (e.g., B = −0.01 cm per 10 years of aging, p < 0.001). Increased diastolic blood pressure was associated with lower spinal cord motion and CSF flow parameters (e.g., C2/C3 CSF stroke volume B = −0.3 mL per 10 mmHg, p < 0.001). Males showed higher CSF flow and spinal cord motion (e.g., CSF stroke volume B = +0.5 mL, p < 0.001; total displacement spinal cord B = +0.016 cm, p = 0.002). We therefore propose to stratify data for age and sex and to adjust for diastolic blood pressure and segmental narrowing in future clinical studies.

Non-invasive biomarkers for spontaneous intracranial hypotension (SIH) through phase-contrast MRI

“…[33] Given the previously described age-related changes in CSF and spinal cord velocities, the use of adapted data assumes significance. [25] The moderate relation between spinal cord motion and the Bern score, which encompasses but is not limited to signs of brain sagging, suggests a potential, yet moderate link. It might be hypothesized that increased craniocaudal spinal cord motion per heartbeat may reflect a component of the overall induced mechanic stress to the adherent meningeal tissues caused by spinal CSF loss that are discussed to be involved within the pain circuits in SIH [14].…”

“…Additionally, patient data was pooled with previously published, prospective data of 20 SIH patients positive for SLEC assessed between October 2021 and February 2022 [ 24 ]. The entire pooled data was then compared to data of 70 healthy controls from the database (age 20–79 years, mean age 45.2 ± 16 years, 56% women) [ 25 ]. The local ethical board granted approval for the prospective trial (vote number: 338/17), and the subsequent retrospective analysis (vote number: 22-1512_1-S1-retro).…”

“…1 ). The training procedures and the further processing steps have been described in detail before [ 24 , 25 ], and are summarized in Supplement 1. MRI data curation involved exclusion of datasets with typical MRI artifacts (e.g., movement, metal, infolding), and/or exclusion of velocity curves that did not follow a typical pattern of CSF- or spinal cord motion as displayed in Fig.…”

“…1 (examples in Supplement 1). Data validity of the methods regarding test–test and test–retest reliability has been investigated and reported before (Supplement 1) [ 24 , 25 ]. The Intra-class correlation coefficient was > 0.9 for any value.…”

“…and specificity (spec.) non-adjusted thresholds should be adapted to age by about 10% per each decade exceeding the age of 45 years[25]…”