ABSTRACT
Before the first CT studies, only highly invasive radiological approaches could be utilized to evaluate brain structural abnormalities in human subjects. Pneumoencephalography, which consisted of an Xray after air injection into the encephalon through a lumbar puncture, was utilized during the first half of the 20th century to examine the ventricular system. This technique has provided the first in vivo indications of enlarged ventricles and cortical atrophy on schizophrenic patients [3]. The advent of CT yielded a booming interest on structural neuroimaging of psychiatric disorders. Measurements of ventricular dilatation and cortical and cerebellar atrophy could then be performed in several psychiatric disorders [4]. But the evaluation of specific brain structures was still challenging, due to the limited contrast between gray and white matter observed in the CT images. Also, artifacts on the posterior fossa were relatively common owing to dense bone structures surrounding this region, which made brainstem and cerebellum more difficult to evaluate with CT scans. Most of the shortcomings in the earlier structural brain imaging studies were overcome with the advent of magnetic resonance imaging (MRI).
