CT Maxillofacial Temporal bone CT (complementary to MRI in patients with facial nerve palsy) is the preferred CT study and typically provides better spatial resolution than maxillofacial CT when assessing the fine detailed anatomy of the temporal bone and bony facial nerve canal. Maxillofacial CT provides better spatial resolution than head CT and, depending on institutional protocols, may provide sufficient spatial resolution to be complementary to MRI to characterize the osseous integrity of the temporal bone and assess the extracranial course of the facial nerve although the nerve itself is not directly imaged with CT [2,99,105-108]. Contrast may be useful when infection or a tumor is suspected. There is no relevant literature to support the use of combined pre- and postcontrast imaging. CTA Head There is no relevant literature to support the use of CTA head as an isolated study in the initial evaluation of acute unilateral facial nerve palsy. Rarely brainstem or cortical infarct can result in isolated facial nerve palsy, and if clinically suspected, CTA may be complementary to MRI in this clinical scenario [102,103] to characterize the vasculature. CTA is uncommonly reported as a complementary study to thin-cut high-resolution MRI for characterizing the anatomy of vascular loops potentially compressing the centrally myelinated portion of the facial nerve [109]. FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT skull base to mid-thigh in the evaluation of isolated unilateral facial nerve palsy or hemifacial spasm. MRA Head There is no relevant literature to support the use of MRA alone in the initial evaluation of acute unilateral facial nerve palsy. Rarely brainstem or cortical infarct can result in isolated facial nerve palsy, and if clinically suspected, MRA may be complementary to MRI in this clinical scenario [102,103] to characterize the vasculature. MRA may be useful in the assessment of hemifacial spasm.
Cranial Neuropathy. CT Maxillofacial Temporal bone CT (complementary to MRI in patients with facial nerve palsy) is the preferred CT study and typically provides better spatial resolution than maxillofacial CT when assessing the fine detailed anatomy of the temporal bone and bony facial nerve canal. Maxillofacial CT provides better spatial resolution than head CT and, depending on institutional protocols, may provide sufficient spatial resolution to be complementary to MRI to characterize the osseous integrity of the temporal bone and assess the extracranial course of the facial nerve although the nerve itself is not directly imaged with CT [2,99,105-108]. Contrast may be useful when infection or a tumor is suspected. There is no relevant literature to support the use of combined pre- and postcontrast imaging. CTA Head There is no relevant literature to support the use of CTA head as an isolated study in the initial evaluation of acute unilateral facial nerve palsy. Rarely brainstem or cortical infarct can result in isolated facial nerve palsy, and if clinically suspected, CTA may be complementary to MRI in this clinical scenario [102,103] to characterize the vasculature. CTA is uncommonly reported as a complementary study to thin-cut high-resolution MRI for characterizing the anatomy of vascular loops potentially compressing the centrally myelinated portion of the facial nerve [109]. FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT skull base to mid-thigh in the evaluation of isolated unilateral facial nerve palsy or hemifacial spasm. MRA Head There is no relevant literature to support the use of MRA alone in the initial evaluation of acute unilateral facial nerve palsy. Rarely brainstem or cortical infarct can result in isolated facial nerve palsy, and if clinically suspected, MRA may be complementary to MRI in this clinical scenario [102,103] to characterize the vasculature. MRA may be useful in the assessment of hemifacial spasm.