No abstract

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.

Human lumbar discs do not reconstitute after chemonucleolysis. Because the long-term temporal course of disc height in patients is in disagreement with observations from animal experiments, caution is suggested when generalizing results from animal studies to humans.

A review was made of the computed tomographic (CT) studies of 33 patients with hormone-secreting microadenomas that had been verified by transsphenoidal surgery and endocrinologic evaluation. In previous studies in small series of patients, the CT appearance of pituitary microadenomas has been reported as hypodense, isodense, and hyperdense. In this study, CT showed a region of diminished enhancement and usually an enlarged pituitary gland in cases of prolactin-secreting adenomas. HGH- or ACTH-secreting adenomas were less consistently hypodense. It is concluded that hypodensity and enlargement in the pituitary gland are the most useful criteria for identification of microadenomas. Some technical factors that may affect the CT appearance of microadenomas and lead to conflicting reports are discussed.