A history of the path towards imaging of the brain: From skull radiography through cerebral angiography.

This publication reviews the steps in the path towards obtaining a complete image of the brain. Up to the 1920s, plain X-ray films could demonstrate only calcified tumors, shifts in midline position of a calcified pineal gland due to a mass in the cranium, or foreign metallic objects within the skull. Walter Dandy reported in 1918 that he visualized cerebral ventricles by introducing air as a contrast agent through a trocar into one of the occipital lobes or the right frontal horn of the ventricular system. Dandy localized lesions that distorted or shifted the ventricles. In 1920, Dandy placed air by lumbar puncture into the spinal subarachnoid space that could visualize the brain and entire ventricles. Antonio Egas Moniz with the assistance of his neurosurgeon colleague, Almeida Lima, obtained X-ray images of cerebral arteries of dogs and decapitated human heads from corpses after injecting strontium bromide into their carotid arteries. Satisfied by these experiments, Moniz injected strontium bromide directly into carotid arteries of five patients which failed to show intracranial vessels. In the sixth patient, intracranial arteries were outlined but that patient died of cerebral thrombosis presumably due to the hyper-osmolality of that contrast agent. Finally, on June 18, 1927, Moniz injected 22% sodium iodine into a 20-year-old man and obtained clear visualization of his carotid artery and intracerebral branches after temporarily occluding the artery with a ligature. Direct percutaneous puncture of the cervical carotid artery remained the primary technique unto the 1960s to visualize intracranial blood vessels until Seldinger's technique was introduced in 1953. Computerized axial tomography (CAT) and magnetic resonance imaging (MRI) replaced cerebral arteriography for localizing tumors and epidural or subdural hemorrhage. However, angiography is used currently for embolization of aneurysms and removal of thrombi or emboli in patients with acute stroke.