Pituitary fossa: chemical shift effect in MR imaging

The effect of chemical shift on magnetic resonance (MR) imaging of the pituitary fossa was studied. Healthy volunteers underwent conventional MR imaging of the pituitary fossa and then imaging with the frequency-encoding gradient reversed or with the phase- and frequency-encoding gradients interchanged. Comparison of the image pairs in each subject showed that the thin, black stripe evident at the water-fat interface within the pituitary fossa was altered when the gradients were changed. Therefore, the low-intensity signal within the pituitary fossa is a chemical shift misregistration effect.     

Anulus fibrosus in bulging intervertebral disks

In this investigation the association of radial tears of the anulus fibrosus and bulging of the intervertebral disk was studied. An index of disk bulging was measured in sagittal anatomic sections in 149 lumbar disks from 31 cadavers. The indexes of disk bulging were correlated with stages of disk development and the presence of an annular tear. The largest disk-bulging indexes were always associated with radial tears of the anulus. Eighty-four percent of the disks with radial tears had disk-bulging indexes greater than 2.5 mm. Most normal adult disks had an index of less than 2.5 mm. The results challenge the concept that the anulus fibrosus is intact in bulging disks, although ruptured in herniated disks.     

Variation in evoked potential measures over the menstrual cycle: A pilot study

Nancy Kluck, Scan J. O'Connor, Victor M. Hesselbrock, Allan Tasman and Donald Maier, Lance Bauer: Variation in Evoked Potential Measures Over the Menstrual Cycle: A Pilot Study. Prog. Neuro. Psychopharmacol. Biol. Psychiat. 1992. 16(6): 901–911.

1. 1. The P3 component of a visual event related potential (ERP) was studied for five consecutive weeks in six women with normal menstrual cycles. Serum concentrations of luteinizing hormone (LH), estradiol (E2) and progesterone were studied during the same period.

2. 2. Increases in P3 amplitude, although nonsignificant, were noted in the week preceding onset of menses.

3. 3. No significant changes in reaction times to target/nontarget stimuli were noted over the same time period.

Depression among patients with a chief complaint of chronic fatigue

The prevalence of mood disorders among patients with chronic fatigue was examined in a group of 100 adults who had experienced fatigue symptoms for an average of 13 years. Patients received a comprehensive history, physical and laboratory evaluation and completed the National Institute of Mental Health Diagnostic Interview Schedule and the Beck Depression Inventory (BDI). Among 44 patients with depressive illness, the onset of their first depressive episode was strongly associated with and preceded the onset of chronic fatigue. The BDI, fatigue history, demographic factors, and findings from the physical examination and laboratory had only modest success in discriminating those patients with depressive illness from other patients. We conclude that depressive illness is an important precursor of chronic fatigue.