Magnetic resonance imaging of high level autism.

Abstract

Noninvasive brain imaging changed rapidly in the decade of the 1970s. Computed tomography (CT) revolutionized central nervous system (CNS) imaging, subsequently advancing adult and pediatric neurology. Psychiatry, although impacted by CT, saw fewer advances as a result of the technology. Certain syndromes such as schizophrenia and bipolar illness, were found to have ventricular abnormalities on CT (Nasrallah & Coffman, 1985); however, child psychiatric syndromes-Tourette 's syndrome and infantile-onset autism-yielded inconsistent results. A recent study concluded that child psychiatry patients "without other neurologic problems are very unlikely to have detectable CT scan abnormalities" (Harcherik et al., 1985). Thus, the initial enthusiasm for CT scanning in child psychiatry patients appears to have dampened. The development of magnetic resonance imaging (MRI) again measurably improves CNS visualization. MRI appears to be superior to CT in central nervous system imaging (Latack et al., 1968; Steiner, 1985). It has particular advantages in children: no ionizing radiation (Han et al., 1985); no intravenous corltrast material injections (Zimmerman & Bilaniuk, 1986); no skull artifact in the posterior fossa (Packer et al., 1984). Because of gray-white matter delineation, MRI is superior when examining the developing brains of children (Johnson & Bydder, 1983). Moreover, multiple scanning orientations are possible; brain areas which have been hypothesized to be involved in autism may now be investigated. For example, the cingulate gyrus (Damasio, 1982) and the brain stem (Ornitz, 1983) have been implicated in autistic behavior. Both these areas are not delineated as clearly in CT scans as in midsagittal MRI. Hence, previous negative CT findings may be a consequence of the limitations of the technology. Thus,