Depending on institutional protocols used for high-resolution skull base imaging, maxillofacial CT may be complementary to an MRI exam if a skull base lesion is found to be the cause of multiple middle CN palsies and can be useful to characterize the osseous integrity of the skull base, intratumoral calcification, and skull base foramina [134]. Contrast should be administered. Noncontrast CT may also be an alternate option when used as complementary to the MRI. There is no relevant literature to support the use of combined pre- and postcontrast imaging. CT Temporal Bone There is no relevant literature to support the use of temporal bone CT in the initial evaluation of multiple middle CN palsies. Depending on institutional protocols used for high-resolution skull base imaging, temporal bone CT may be complementary to contrast-enhanced MRI if a skull base lesion is found to be the cause of multiple middle CN palsies and can be useful to characterize the osseous integrity of the base, intratumoral calcification, and skull base foramina [134]. Contrast should be administered. Noncontrast CT may also be an alternate option when used as complementary to the MRI. There is no relevant literature to support the use of combined pre- and postcontrast imaging. CT Neck There is no relevant literature to support routine use of neck CT in the initial evaluation of multiple middle cranial palsies. If perineural tumor spread (discussed in Variant 10) is suspected based on clinical features, most notably involving both CNs V and VII, neck CT is complementary to MRI for characterizing osseous changes of skull base neural foramina and may be useful to characterize perineural fat and stage the neck [64,66]. Contrast should be administered if possible. There is no relevant literature to support the use of combined pre- and postcontrast imaging. CTA Head There is no relevant literature to support routine use of CTA head in the initial evaluation of multiple middle cranial palsies.
Cranial Neuropathy. Depending on institutional protocols used for high-resolution skull base imaging, maxillofacial CT may be complementary to an MRI exam if a skull base lesion is found to be the cause of multiple middle CN palsies and can be useful to characterize the osseous integrity of the skull base, intratumoral calcification, and skull base foramina [134]. Contrast should be administered. Noncontrast CT may also be an alternate option when used as complementary to the MRI. There is no relevant literature to support the use of combined pre- and postcontrast imaging. CT Temporal Bone There is no relevant literature to support the use of temporal bone CT in the initial evaluation of multiple middle CN palsies. Depending on institutional protocols used for high-resolution skull base imaging, temporal bone CT may be complementary to contrast-enhanced MRI if a skull base lesion is found to be the cause of multiple middle CN palsies and can be useful to characterize the osseous integrity of the base, intratumoral calcification, and skull base foramina [134]. Contrast should be administered. Noncontrast CT may also be an alternate option when used as complementary to the MRI. There is no relevant literature to support the use of combined pre- and postcontrast imaging. CT Neck There is no relevant literature to support routine use of neck CT in the initial evaluation of multiple middle cranial palsies. If perineural tumor spread (discussed in Variant 10) is suspected based on clinical features, most notably involving both CNs V and VII, neck CT is complementary to MRI for characterizing osseous changes of skull base neural foramina and may be useful to characterize perineural fat and stage the neck [64,66]. Contrast should be administered if possible. There is no relevant literature to support the use of combined pre- and postcontrast imaging. CTA Head There is no relevant literature to support routine use of CTA head in the initial evaluation of multiple middle cranial palsies.