useful for people whose symptoms worsen over time or when structural pathology is suspected. CT of the head is sometimes used for people who have sudden hearing loss. However when there are not other neurological findings, a history of trauma, or a history of ear disease, CT scans are not useful and should not be used in response to sudden hearing loss. CT of the head is also used in CT-guided stereotactic surgery and radiosurgery for treatment of intracranial tumors, arteriovenous malformations and other surgically treatable conditions. Orbital views for eye-related disorders Special views focusing on the orbit of the eye may be taken to investigate concerns relating to the eye. CT scans are used by physicians specializing in treating the eye (ophthalmologists) to detect foreign bodies (especially metallic objects), fractures, abscesses, cellulitis, sinusitis, bleeding within the skull (intracranial bleeding), proptosis, Graves disease changes in the eye, and evaluation of the orbital apex and cavernous sinus. Comparison with MRI Magnetic resonance imaging (MRI) of the head provides superior information as compared to CT scans when seeking information about headache to confirm a diagnosis of neoplasm, vascular disease, posterior cranial fossa lesions, cervicomedullary lesions, or intracranial pressure disorders. It also does not carry the risks of exposing the person to ionizing radiation. CT scans may be used to diagnose headaches when neuroimaging is indicated and MRI is not available, or in emergency settings when hemorrhage, stroke, or traumatic brain injury is suspected. MRI (magnetic resonance imaging) provides more sensitivity in the evaluation of the cavernous sinus and the orbital apex. One advantage over a brain MRI is in the evaluation of intracerebral calcifications. Cautions Several different views of the head are available, including axial, coronal, reformatted coronal, and reformatted sagittal images. However, coronal images require the person to hyperextend their neck, which must be avoided if any possibility of neck injury exists. CT scans of the head increase the risk of brain cancer, especially for children. As of 2018, it appeared that there was a risk of one excess cancer per 3,000–10,000 head CT exams in children under the age of 10. See also Neuroimaging References X-ray computed tomography