MRI-guided definition of cerebrospinal fluid distribution around cranial and sacral nerves: implications for brain tumors and craniospinal irradiation

Figures & data

Figure 1. Extension of the CSF within the dural sheaths of the optic nerve (A), trigeminal nerve (B), facial and vestibulo-cochlear nerves (C), the glossopharyngeal, vagus and accessory nerves (D) the hypoglossal nerve (E) and at spinal levels L5/S1 (F) and S1/S2 (G). Images in the left column are acquired using a coronal 3D T2 TSE with a TR/TE = 8000/1094 ms, acquired resolution of 0.75 × 1.5 × 0.75 mm³ and reconstructed to 0.75 × 0.75 × 0.75 mm³ with SPIR fat suppression. The MR images in the right column are acquired using a coronal 3D T2 TSE with TR/TE = 1800/171 ms, acquired resolution of 2.0 × 2.0 × 2.0 mm³ and reconstructed to 1.0 × 1.0 × 1.0 mm³ with SPAIR fat suppression.

Table 1. CSF extension within the dural sheath of the cranial nerves, measured from the inner table of the skull.

Nerve	Mean (mm)	95% CI (mm)	Maximum extension (mm)
Olfactory nerve (I)	Not visible	Not visible	Not visible
Optic nerve (II)	40	[38–42]	45
Oculomotor nerve (III)	Not visible	Not visible	Not visible
Trochlear nerve (IV)	Not visible	Not visible	Not visible
Trigeminal nerve (V)	16	[15–19]	21
Abducens nerve (VI)	Not visible	Not visible	Not visible
Facial nerve (VII)	11	[11–12]	14
Vestibulo-cochlear nerve (VIII)	11	[11–12]	14
Glossopharyngeal nerve (IX)	7	[7–9]	10
Vagus nerve (X)	7	[7–9]	10
Accessory nerve (XI)	7	[7–9]	10
Hypoglossal nerve (XII)	8	[7–9]	10