A L Williams

The CT appearance of the vascular, ligamentous, and neural tissues in the spinal canal was studied in 50 patients and 5 cadavers. In some patients, iodinated contrast medium was first injected into the ascending lumbar veins, nucleus pulposus, or theca. Positive identification of spinal soft tissues on the CT image was made by reference to cadaver dissections. The spinal cord, nerves, root sheaths, retrovertebral plexus, epidural and basivertebral veins, posterior longitudinal ligament and ligamentum flavum, intervertebral disks, and vertebral arteries can be demonstrated by CT, indicating its value in the diagnosis of disease of the cord, disk, and epidural space.

Spinal CT scans, plain radiographs, and medical records of 81 patients with an abnormal pars interarticularis were reviewed to define the CT criteria for spondylolysis. In many cases, it was difficult to detect because it simulated the adjacent facet joints; however, it could be differentiated by careful analysis of the section level and the contiguous facet joints, which usually had regular cortical surfaces (in contrast to the pars defects). Spondylolysis was evident on the lateral localizer image in most cases. In some patients the pars appeared abnormally narrow and elongated or sclerotic as well as interrupted. In a few cases, CT demonstrated a pars defect which was not effectively shown by the plain radiographs. In one patient, a herniated disk was also seen.

This study reports the sonographic and computed tomography (CT) findings in seven infants and neonates with intracranial calcifications and a spectrum of underlying disorders, including toxoplasmosis, cytomegalic inclusion disease, transverse/straight sinus thrombosis, and probable anoxia. Neurotropic infectious disease usually produced clumped or subependymal calcifications accompanied by sometimes bizarre ventricular configurations and prominent periventricular cystic encephalomalacia. Sonography failed to identify prospectively intracranial calcifications in two of the three patients without infection, although calcifications were visible in retrospect. Overall, CT provided optimum visualization of intracranial calcifications.

Although computed tomography (CT) has been shown to be useful in diagnosing posterolateral and central lumbar disk herniations, its effectiveness in demonstrating lateral herniated disks has not been emphasized. The myelographic recognition of those herniations may be difficult because root sheaths or dural sacs may not be deformed. A total of 274 CT scans interpreted as showing lumbar disk herniation was reviewed. Fourteen (5%) showed a lateral disk herniation. The CT features of a lateral herniated disk included: (1) focal protrusion of the disk margin within or lateral to the intervertebral foramen; (2) displacement of epidural fat within the intervertebral foramen; (3) absence of dural sac deformity; and (4) soft-tissue mass within or lateral to the intervertebral foramen. Because it can image the disk margin and free disk fragments irrespective of dural sac or root sheath deformity, CT may be more effective than myelography for demonstrating the presence and extent of lateral disk herniation.