Robert G. Peyster

Cognitive performance and MR markers of cerebral injury in cognitively impaired MS patients

Objective: To relate neuropsychological performance to measures of cerebral injury in persons with MS selected for cognitive impairment. Methods: Participants were 37 individuals with relapsing–remitting (59.5%) and secondary progressive (40.5%) MS. They were tested at baseline as part of a clinical trial to enhance cognition with an acetylcholinesterase inhibitor. Eligibility criteria included at least mild cognitive impairment on a verbal learning and memory task. A modified Brief Repeatable Battery of Neuropsychological Tests formed the core of the behavioral protocol. Neuroimaging measures were central (ventricular) cerebral atrophy, lesion volume, and ratios of N -acetyl aspartate (NAA) to both creatine and choline. Results: A clear, consistent relation was found between cognitive and MR measures. Among neuroimaging measures, central atrophy displayed the highest correlations with cognition, accounting for approximately half the variance in overall cognitive performance. NAA ratios in right hemisphere sites displayed larger correlations than those on the left. Multiple regression models combining the MR measures accounted for well over half the variance in overall cognitive performance. The Symbol Digit Modalities Test was the neuropsychological task most strongly associated with the neuroimaging variables. Conclusions: If a strong and stable association can be firmly established between cognitive and MR variables in appropriate subsets of MS patients, it might aid in the investigation of interventions to enhance cognition and modify the course of the disease.

The potential for vigabatrin-induced intramyelinic edema in humans.

Summary: Purpose: Vigabatrin (Sabril, Hoechst Marion Roussel) is an antiepilepsy drug (AED) presently marketed in 64 countries for the treatment of partial and secondarily generalized seizures. Vigabatrin (VGB) is marketed in a subset of these countries for the treatment of infantile spasms. Clinical experience in humans has shown that VGB provides effective seizure control with a wide margin of safety. However, animal toxicity studies raised concern when prolonged administration of VGB was shown to induce intramyelinic edema (IME) in some laboratory animal species.

Use of Ex Vivo Magnetic Resonance Imaging to Detect Onset of Vigabatrin-Induced Intramyelinic Edema in Canine Brain

Summary: Vigabatrin (VGB) causes intramyelinic edema (micro vacuolation) in brain of dogs and rodent, which has encouraged development of noninvasive methods to monitor for this effect during clinical trials. We report the qualitative ex vivo magnetic resonance imaging (MRI) changes observed in a neuropathology study in dogs to detect time of onset and regression of VGB‐induced intramyelinic edema. Beagles were randomly assigned to 18 groups of 6 dogs per group and administered vigabatrin orally (p.o.) at a dose of 300 mg/kg/day (2 males, 2 females) or placebo (1 male, 1 female). Animals were killed and examined at weekly intervals during the 12 weeks of treatment and at 1, 2, 4, 8, 12, and 16 weeks after discontinuation of drug treatment. Myelin microvacuolation in thalamus, hypothalamus, and fornix were noted histologically after 4–5 weeks of treatment. Increases in MRI T2 intensity were observed in hypothalamus after 4 weeks and in thalamus and columns of the fornix after 7 weeks. Both MRI T2 intensity and microvacuolation continued to increase during 12‐week VGB treatment. When VGB treatment was discontinued after 12 weeks, both MRI T2 intensity and microvacuolation began to decrease. Six‐teen weeks after VGB discontinuation, histopathology had returned to normal and MRI examination demonstrated a marked trend toward reversal of the increased T2 signal intensity. MRI thus has potential as a noninvasive surveillance technique in certain experimental and clinical conditions associated with intramyelinic edema.

Computed tomography and aging: results in a normal elderly population

SummaryCT studies on 212 normal elderly individuals were analyzed for ventricular enlargement and cortical atrophy. Results show a positive correlation between ventricular enlargement and age with greater degrees of ventricular enlargement and cortical atrophy in men as compared to women. While some degree of atrophy is common in normal elderly individuals it is mild, minimal, or noexistent in 86%.

CT of the normal pituitary gland

SummaryRetrospective evaluation of the pituitary gland on coronal post-contrast CT scan in 251 patients demonstrated that the pituitary gland is somewhat larger in females than in males. In males, glands measuring greater than 7.7 mm should be considered abnormal; in females, a statistically significant decline of gland height occurs with increasing age, the upper limit of normal for female gland height decreasing from 9.2 cm for a 20-year-old to 6.0 cm for a 90-year-old. Focal low densities greater than 3 mm are rare in males and probably should be considered abnormal.

Mammography Parenchymal Patterns and the Prevalence of Breast Cancer1

An investigation of the relationship between breast parenchymal patterns and breast cancer prevalence in a large referral population is presented. Mammograms were assigned to one of four categories according to our interpretation of Wolfes classification. Cancer prevalence for the four patterns was similar when uncorrected for age,, and was very high compared to that in the general population. Under age 50, the prominent duct pattern (P2) was associated with a very high relative cancer risk and DY carried a smaller increased risk. After age 50, prevalences for the patterns were nearly equal. Relationship between these findings and epidemiology of breast cancer are discussed and suggestions made for utilizing parenchymal patterns to guide examination frequency.

Sixth nerve neuroma in the cavernous sinus: CT features.

A sixth nerve neuroma arising within the cavernous sinus is reported. This is the third sixth nerve neuroma cited in the world literature and the first to have CT demonstration. The unusual CT enhancement characteristics excluded the more common cavernous sinus masses and suggested the correct diagnosis preoperatively.

Giant Intracranial Aneurysm in a Child with Tuberous Sclerosis: CT Demonstration

The authors describe the first case of giant intracranial aneurysm in a child with tuberous sclerosis. The subject of vascular disease in this condition is reviewed.

Sixth nerve schwannoma: MR and CT demonstration.

A sixth nerve schwannoma arising in the region of the pons and midbrain is reported. The magnetic resonance and CT characteristics are discussed.

Differential diagnosis of the enlarged superior ophthalmic vein.

Enlargement of the superior ophthalmic vein (SOV), although usually considered a sign of carotid-cavernous fistula, may be found with other disorders. Patients with Graves orbitopathy, orbital pseudotumor, and a para-sellar meningioma as the cause of an enlarged SOV as seen on computed tomography are discussed.