Visualization of cerebrospinal fluid flow in syringomyelia through noninvasive magnetic resonance imaging with a time-spatial labeling inversion pulse (Time-SLIP)

Abstract

Context: We report a case of syringomyelia assessed by magnetic resonance imaging (MRI) with a time-spatial labeling inversion pulse (Time-SLIP), which is a non-contrast MRI technique that uses the cerebrospinal fluid (CSF) as an intrinsic tracer, thus removing the need to administer a contrast agent. Time-SLIP permits investigation of flow movement for over 3 seconds without any limitations associated with the cardiac phase, and it is a clinically accessible method for flow analysis.

Findings: We investigated an 85-year-old male experiencing progressive gait disturbance, with leg numbness and muscle weakness. Conventional MRI revealed syringomyelia from C7 to T12, with multiple webs of cavities. We then applied the Time-SLIP approach to characterize CSF flow in the syringomyelic cavities. Time-SLIP detected several unique CSF flow patterns that could not be observed by conventional imaging. The basic CSF flow pattern in the subarachnoid space was pulsatile and was harmonious with the heartbeat. Several unique flow patterns, such as bubbles, jumping, and fast flow, were observed within syringomyelic cavities by Time-SLIP imaging. These patterns likely reflect the complex flow paths through the septum and/or webs of cavities.

Conclusion/clinical relevance: Time-SLIP permits observation of CSF motion over a long period of time and detects patterns of flow velocity and direction. Thus, this novel approach to CSF flow analysis can be used to gain a more extensive understanding of spinal disease pathology and to optimize surgical access in the treatment of spinal lesions. Additionally, Time-SLIP has broad applicability in the field of spinal research.

Keywords: Cerebrospinal fluid (CSF); Magnetic resonance imaging (MRI); Spinal disease; Syringomyelia; Time-spatial labeling inversion pulse (Time-SLIP).

Figure 1

An 85-year old man with syringomyelia. Routine MRI revealed a cavity localized from C7 to T12 that had a gradually enlarged horn and a long thoracic tail. T1-weighted imaging detected syrinxes forming multiple webs and T2-weighted imaging showed syringomyelic cysts within the spinal cord.

Figure 2

Time-SLIP MRI images at C0–2. Time-SLIP revealed both intra- and peri-spinal cord CSF flow dynamics. The flow complex at the upper cervical level showed a basic flow pattern of pulsatile flow motion in the cranio-caudal direction, which was dominant in the ventral space compared to the dorsal space (arrow).

Figure 3

Time-SLIP images of the head of syringomyelia (C6/7). Time-SLIP revealed CSF inflow through the central canal of the spinal cord, moving slowly with pulsatile motion in the caudal direction. The direct interaction between the aqueduct and syringomyelic cavity may contribute to the pathologic mechanism of syrinx formation.

Figure 4

Time-SLIP image at T4. This figure reveals direct interactions between compartments in syringomyelia resulting from direct connections and flow throughout the web-like cavities.