CSF flow waveform analysis helps demonstrate abnormalities in CSF flow at the foramen magnum and the benefits of decompressive surgery in patients with the Chiari I malformation.

Our purpose in this investigation was to explain the heterogeneity in the cerebrospinal fluid (CSF) flow pulsation amplitudes. To this end, we determined the contributions of the cerebral arterial and jugular venous flow pulsations to the amplitude of the CSF pulsation. We examined 21 healthy subjects by cine phase-contrast MRI at the C2-3 disc level to demonstrate the CSF and vascular flows as waveforms. Multiple regression analysis was performed to calculate the contributions of (a) the arterial and venous waveform amplitudes and (b) the delay between the maximum systolic slopes of the arterial and venous waveforms (AV delay), in order to predict the amplitude of the CSF waveform. The contribution of the arterial waveform amplitude was positive (r = 0.61; p = 0.003) to the CSF waveform amplitude and that of the venous waveform amplitude was negative (r = -0.50; p = 0.006). Both in combination accounted for 56% of the variance in predicting the CSF waveform amplitude (p < 0.0006). The contribution of AV delay was not significant. The results show that the variance in the CSF flow pulsation amplitudes can be explained by concurrent evaluation of the CSF and vascular flows. Improvement in the techniques, and controlled experiments, may allow use of CSF flow pulsation amplitudes for clinical applications in the non-invasive assessment of intracranial dynamics by MRI.

Segmental spinal dysgenesis is characterized by focal agenesis or dysgenesis of the lumbar or thoracolumbar spine, with focal abnormality of the underlying spinal cord and nerve roots. Children are symptomatic at birth with lower limb deformities and neurological deficits that may be segmental. Myelography and computed tomography disclose hypoplastic or absent vertebrae and atrophic or absent neural elements adjacent to the bony deformity; the spinal column distal to the abnormality may be partially bifid, but is otherwise normal. Spinal ultrasonography was a helpful diagnostic adjunct in one patient. Surgery may be helpful in decompressing partially functioning spinal cord or nerve roots, but may exaggerate the tendency toward spinal instability. The embryology of this abnormality is not clear, but two children had other anomalies suggesting a spinal dysraphic syndrome, and its cause is probably related to a segmental maldevelopment of the neural tube.

The purpose of this study was to explore the value of high-detail MR imaging in the diagnosis of the Chiari II malformation.

Four children with previously repaired myelomeningoceles presented toward the end of the first decade or early in the second decade of life with deteriorating lower-extremity and bladder function. Myelography and computerized tomography scanning demonstrated irregular filling defects at the area of the myelomeningocele repair, and surgical exploration disclosed dermoid tumors that were adherent to the placode and adjacent roots. Dermoid tumors should be considered in the differential diagnosis of neurological deterioration in children with a repaired myelomeningocele.

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