CT may be helpful for visualizing perineural fat planes, which can be distorted or obliterated in patients with lesions affecting the trigeminal nerve, although MRI offers improved detection of perineural tumor spread (discussed in Variant 10) compared with CT, which has a sensitivity and specificity of 88% and 89%, respectively [64-66]. CT with IV contrast offers the benefits of vascular and mucosal enhancement and may highlight enhancing lesions. There is no relevant literature to support the use of combined pre- and postcontrast imaging. Thin section contrast-enhanced navigation protocol CT is useful for noninvasive treatment planning in patients with known trigeminal neuralgia [67]. CTA Head There is no relevant literature to support the use of CTA head in the initial evaluation of trigeminal neuropathy. In patients with clinical features of trigeminal neuralgia, high-resolution combined MRI, MRA, and CTA may be used to assess for vascular loops compressing the fifth nerve. Anatomic and dedicated vascular imaging play a complementary role. Structural MRI evaluation of the nerve and its relationship to vasculature is more commonly reported in the literature, likely related to the improved soft tissue contrast of MRI compared with CT [23,68-76]. CTA has been used to characterize the relationship of arterial vasculature relative to the fifth nerve in patients with a clinical diagnosis of trigeminal neuralgia but is less commonly used than MRI and MRA because it does not provide simultaneous high-resolution imaging of the trigeminal nerve provided by MRI [77]. MRA Head There is no relevant literature to support the use of MRA head in the initial evaluation of trigeminal neuropathy.
Cranial Neuropathy. CT may be helpful for visualizing perineural fat planes, which can be distorted or obliterated in patients with lesions affecting the trigeminal nerve, although MRI offers improved detection of perineural tumor spread (discussed in Variant 10) compared with CT, which has a sensitivity and specificity of 88% and 89%, respectively [64-66]. CT with IV contrast offers the benefits of vascular and mucosal enhancement and may highlight enhancing lesions. There is no relevant literature to support the use of combined pre- and postcontrast imaging. Thin section contrast-enhanced navigation protocol CT is useful for noninvasive treatment planning in patients with known trigeminal neuralgia [67]. CTA Head There is no relevant literature to support the use of CTA head in the initial evaluation of trigeminal neuropathy. In patients with clinical features of trigeminal neuralgia, high-resolution combined MRI, MRA, and CTA may be used to assess for vascular loops compressing the fifth nerve. Anatomic and dedicated vascular imaging play a complementary role. Structural MRI evaluation of the nerve and its relationship to vasculature is more commonly reported in the literature, likely related to the improved soft tissue contrast of MRI compared with CT [23,68-76]. CTA has been used to characterize the relationship of arterial vasculature relative to the fifth nerve in patients with a clinical diagnosis of trigeminal neuralgia but is less commonly used than MRI and MRA because it does not provide simultaneous high-resolution imaging of the trigeminal nerve provided by MRI [77]. MRA Head There is no relevant literature to support the use of MRA head in the initial evaluation of trigeminal neuropathy.