CSF Flow and Spinal Cord Motion in Patients With Spontaneous Intracranial Hypotension

Abstract

Background& Objectives: Spontaneous intracranial hypotension (SIH) is characterized by loss of CSF-volume. We hypothesize that in this situation of low volume, a larger CSF-flow and spinal cord motion at the upper spine can be measured by non-invasive phase-contrast MRI.Methods:A prospective, age-, gender- and BMI- matched controlled cohort study on SIH patients presenting with spinal longitudinal extradural fluid collection (SLEC) was conducted November 2021 to February 2022. Adapted cardiac-gated 2D phase-contrast MRI sequences were acquired at segment C2/C3, and C5/C6 for CSF-flow, and spinal cord motion analysis. Data processing was fully automated. CSF-flow and spinal cord motion were analyzed by peak-to-peak-amplitude and total displacement per segment and heartbeat, respectively. Clinical data included: age, height, body mass index, duration of symptoms, Bern score according to Dobrocky et al. 2019, and type of the spinal CSF leak according to Schievink et al. 2016. Groups were compared via Mann-Whitney U-test; multiple linear regression analysis was performed to address possible relations.Results:20 SIH patients and 40 healthy controls were analyzed; each group consisted of 70% women. 11 SIH patients presented with Type 1 leak, eight with Type 2, and one was indeterminate. CSF flow per heartbeat was increased at C2/C3 (peak-to-peak-amplitude 65.68 ± 18.3 mm/s vs. 42.50 ± 9.8 mm/s, total displacement 14.32 ± 3.5 mm vs. 9.75 ± 2.7 mm, p<0.001, respectively). Craniocaudal spinal cord motion per heartbeat was larger at segment C2/C3 (peak-to-peak-amplitude 7.30 ± 2.4 mm/s vs. 5.82 ± 2.0 mm/s, total displacement 1.01 ± 0.4 mm vs. 0.74 ± 0.4 mm, p=0.006, respectively) and at segment C5/C6 (total displacement 1.41 ± 0.7 mm vs. 0.97 ± 0.4 mm, p=0.021).Discussion:SLEC-positive SIH patients show higher CSF-flow and higher spinal cord motion at the upper cervical spine. This increased craniocaudal motion of the spinal cord per heartbeat might produce increased mechanic strain on neural tissue and adherent structures which may be a mechanism leading to cranial nerve dysfunction, neck pain and stiffness in SIH. Non-invasive phase-contrast MRI of CSF-flow and spinal cord motion is a promising diagnostic tool in SIH.German Clinical Trials Register, identification number:DRKS00017351Classification of Evidence:This study provides Class III evidence that non-invasive phase-contrast MRI of the upper spine identifies differences in CSF-flow and spinal cord motion in SIH patients compared to healthy controls.

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

“…Segmentation and data analysis were fully automated based on the in-house platform NORA (www.nora-imaging.org, 25 Figure 1; see also Figures 3-5). The training procedures and implementations have been described before 4,26 ; further details of the segmentation process and reliability data can be found in Supporting Information S1. All images were inspected visually for artifacts (e.g., movement, metal, infoldings, vascular flow artifacts), and for correct segmentation; agreement of at least two raters (SB; MH; KW) was required before entering further analysis.…”

“…Applying this method, we were recently able to describe a relevant increase in CSF and spinal cord velocities in a cohort of patients with spontaneous intracranial hypotension (SIH) presenting with definite leak. 4 In this phenomenon, which is caused by spinal CSF-volume loss, clinical and diagnostic work-up can be very challenging due to multiform clinical presentation and/or missing signs in conventional MRI. Thus, targeting the change in CSF flow and spinal cord motion would possibly help to identify those patients that need to undergo further invasive diagnostics.…”

Spinal cord motion assessed by phase-contrast MRI - An inter-center pooled data analysis

“…While qualitative measures of CSF flow are acknowledged as part of clinical routine diagnostics (normal pressure hydrocephalus, Chiari I malformation), quantitative analysis is challenged by fluid dynamics, such as bidirectional flow, turbulences, and multiform boundaries ( Bunck et al, 2011 ). In contrast, craniocaudal motion of the spinal cord can be quantitatively and qualitatively measured ( Hupp et al, 2019 , Hupp et al, 2021 Mar , Wolf et al, 2021 , Wolf et al, 2021 , Wolf et al, 2022 ). It has the benefit of fast and reliable assessment, segmentation, and processing.…”

“…Additionally, relevant increases of spinal cord motion at segment C2/C3 have also been depicted in patients with spontaneous intracranial hypotension and definite leak ( Wolf et al, 2022 ), and decreased spinal cord motion in cases with idiopathic intracranial hypertension ( Wolf et al, 2022 ) which is most likely caused by the loss, or the surplus of the surrounding resistances due to alterations in CSF volume, respectively.…”

Phase Contrast Spine MRI for the Evaluation of CSF Leak, and Why It Matters

“…In this issue of Neurology ®, Wolf et al 8 report the results of a prospective, single-center, observational study comparing 20 cases of patients with SIH and an epidural collection with a matched cohort of 40 healthy controls. Their results suggest that phase contrast MRI sequences can detect higher CSF flow and greater spinal cord motion in the cervical spine among the patients with SIH than in the nonleaking controls.…”