High-signal foci on MR images of the brain: observer variability in their quantification.

Foci of high signal in the cerebral white matter are common incidental findings on MR images of the brain of control subjects or patients with a variety of diseases. Although the number of foci has been reported to correlate with age and several risk factors, the degree of observer variability in quantifying foci has not been reported. We used kappa statistics to determine radiologists' agreement in counting high-signal-intensity foci on MR images obtained in healthy volunteers and in patients with hypertension.

High-intensity signals within the posterior pituitary fossa: a study with fat-suppression MR techniques.

Five different theories have been proposed to explain the high-intensity signals within the posterior pituitary fossa seen on MR: (1) a paramagnetic effect of phospholipids in the posterior lobe, (2) lipid in pituicytes in the posterior lobe of the pituitary, (3) neurosecretory granules in the posterior lobe, (4) fat within the sella but outside the pituitary gland, and (5) fat in bone marrow in the dorsum sellae. Previous reports have contained conflicting evidence on which of these structures is the cause of the high-intensity signals within the posterior sella. The purpose of this study was to examine the high-intensity signals of the normal posterior sella with fat-suppression MR techniques to reevaluate the contribution of fat to those signals.

Osteoporosis with vertebral compression fractures, retropulsed fragments, and neurologic compromise.

Osteoporosis frequently affects the vertebral column and causes compression fractures, biconcave ("fish-mouth") vertebrae, kyphosis, and pain. The cases are reported of three postmenopausal osteoporotic women who had neurologic symptoms of the lower extremities because of vertebral body fractures with a retropulsed fragment narrowing the spinal canal. None of the women had experienced trauma.

Bone marrow patterns in aplastic anemia: observations with 1.5-T MR imaging.

Six patients diagnosed as having aplastic anemia underwent magnetic resonance (MR) imaging. The bone marrow in the lumbar spine, pelvis, and proximal femora was examined in each case. One patient had a normal marrow signal intensity (SI) and pattern and was considered cured of disease.