[Imaging in the evaluation of headaches]

Headache is a common complaint in primary care medicine. Most of the time, they are primary and benign headaches, with no need for further investigations; nevertheless, in the presence of red flags, a brain imaging is warranted. The diagnostic approach depends upon the most likely suspected cause and the degree of emergency. In those situations, a head CT scan without and with contrast is the exam of choice in most patients, because it is helpful for identifying intracranial lesions or bleeding. The MRI, more sensible, is preferred in the ambulatory setting for investigation and follow-up of intracranial tumoral or infectious diseases.