Computed Tomography and Magnetic Resonance Imaging:
Their Uses in the Diagnosis of Brain Disorders
The use of computed tomography (CT) and magnetic resonance imaging (MRI) present both advantages and disadvantages relative to imaging for the diagnosis of brain disorders. While the MRI typically yields superior visibility of the suspected brain tumor mass, CT is superior to the use of radionuclide scans to set primary intracranial lesions. Further, while MRI does not "see" (image) bone, thus making it superior to CT for suspected intracranial brain tumor, its viability in scanning for vascular disease is as of yet unproved. In addition to these, contrast-enhanced CT appears to be superior to MRI flow measurements in the investigation of plaque morphology (Troupin, 1985).
Kim and Haynie (1987, p. 71) note that single-photon emission computed tomography (SPECT) is similar conceptually to x-ray computed tomography. Frackowiak (Terry, 1988, p. 89) reports that computed tomography (CT) also includes single-photon counting systems (SPC) and magnetic resonance imaging (MRI). Kim and Haynie (1987) indicate that all of these computed tomography reconstruction techniques prove invaluable to diagnostic imaging.
There are several points of comparison between SPECT and x-ray CT, including the generation of focal points, detail, generation of cross-sectional images, and contrast resolution (Powers & James, 1984, p. 185). With the use of SPECT, which requires the rotation of the scintillation camera around the axis of the patient, imaging can be done every few degrees for the total 3600. As well, with the filtered back-projection technique of reconstruction used in x-ray transmission CT, there can be generated cross-sectional images in any plane. As a result, there is the elimination of superimposed radionuclide activity and increased contrast resolution. Further, with the use of MRI, scanning for intracranial tumors is superi...