Differential aging of the medial temporal lobe: a study of a five-year change.

OBJECTIVE: To test the hypothesis that entorhinal cortex (EC) volume decreases at a slower rate than the hippocampal (HC) volume in healthy adults, and to examine whether the rate of shrinkage increases with age. METHODS: Volumes of the HC and EC were measured twice on MRI scans of 54 healthy adults (aged 26 to 82 years), with an average interval of 5 years. RESULTS: Markedly different age trends were noted in the examined regions. The EC showed no age-related differences on both occasions and only minimal age-related change (0.33%/y). By contrast, the HC exhibited significant age-related differences at baseline and at follow-up evaluation and decreased at a faster pace of 0.86%/y. Older participants (aged > or = 50 years) showed increased annual shrinkage of the HC (1.18%) and EC shrinkage (0.53%/y). The rate of HC volume loss significantly exceeded that of the EC. No EC shrinkage and modest HC volume reduction were observed in people aged <50 years. CONCLUSIONS: Age-related shrinkage occurs in the medial temporal lobes of healthy adults, with significant hippocampal decline and minimal entorhinal changes. In both regions, the rate of decline accelerates with age, although the role of pathologic factors in age-related increase of volume loss merits further investigation.

Age and sex differences in the cerebellum and the ventral pons: a prospective MR study of healthy adults.

BACKGROUND AND PURPOSE: The human brain exhibits a complex pattern of differential aging. The purpose of this study was to examine whether age differences in the volume of cerebellar regions and the ventral pons are differential or generalized, whether the age-related shrinkage is linear or exponential, and whether there are sex differences in the size of the cerebellum and pons. METHODS: The volumes of the cerebellar hemispheres (excluding the vermis and the peduncles), the vermis, and the ventral pons were estimated from the prospectively acquired MR scans of 190 healthy volunteers (aged 18-81 years). The relation between regional volumes, age, and sex was assessed while taking into account differences in body size (height). RESULTS: We found a moderate age-related reduction in the volume of the cerebellar hemispheres and the cerebellar vermis. In contrast to previous findings that suggested differential vulnerability of the posterior vermis, the age-related shrinkage of the vermian lobules was uniform-about 2% per decade. In accord with all reports in the literature, the size of the ventral pons was unrelated to age. The volume of the cerebellar hemispheres, the vermis, and the ventral pons were larger in men, even after adjustment for height. The magnitude of the sex difference was the largest in the hemispheres and the anterior vermis, and the smallest in the lobules VI-VII (declive-folium-tuber). CONCLUSION: Moderate age-related shrinkage of the cerebellum and lack of age-related differences in the ventral pons are robust phenomena. However, in all likelihood, the effects of age on the cerebellum are not differential but uniform. The cerebellum and the pons are larger in men than in women and the difference is especially pronounced in the cerebellar hemispheres and the anterior vermis.

Neuroanatomical and cognitive correlates of adult age differences in acquisition of a perceptual-motor skill.

The objective of this study was to examine age differences in procedural learning and performance in conjunction with differential aging of central nervous system (CNS) structures. Sixty-eight healthy volunteers (age 22-80) performed a pursuit rotor task (four blocks of 20 15-second trials each). Volumes of the cerebellar hemispheres, neostriatum, prefrontal cortex, and hippocampus were measured from Magnetic Resonance (MR) images. Improvement in pursuit rotor performance was indexed by increase in time on target (TOT). A general improvement trend was evident across the blocks of trials. Overall, younger participants showed significantly longer TOT. The rate of improvement was age-invariant during the initial stages of skill acquisition but became greater in middle-aged participants as the practice progressed. When the influences of regional brain volumes were taken into account, the direct age effect on mean TOT measured during the first day of practice disappeared. Instead, reduced volumes of the cerebellar hemispheres and the putamen and poorer performance on nonverbal working memory tasks predicted shorter TOT. In contrast, neither the volume of the caudate and the hippocampus, nor verbal working memory showed association with motor performance. Pursuit rotor performance at the later stages of practice was unrelated to the reduction in putamen volume and was affected directly by age, cerebellar volume, and nonverbal working memory proficiency. We conclude that in a healthy population showing no clinical signs of extrapyramidal disease, age-related declines in procedural learning are associated with reduced volume of the cerebellar hemispheres and lower nonverbal working memory scores. During initial stages of skill acquisition, reduced volume of the putamen is also predictive of poorer performance.

Differential aging of the human striatum: a prospective MR imaging study.

BACKGROUND AND PURPOSE: Advancing age is associated with declines in motor function; understanding age-related changes in the basal ganglia, therefore, is imperative for comprehension of such functional changes. The purpose of this study was to examine the age, sex, and hemispheric differences in volume of the caudate nucleus, the putamen, and the globus pallidus. METHODS: In a sample of 148 healthy right-handed adults (18-77 years old) with no evidence of age-related motor disorders, we estimated the volume of the head of the caudate nucleus, the putamen, and the globus pallidus from MR images. RESULTS: The analyses revealed bilateral age-related shrinkage of the head of the caudate nucleus and the putamen in both sexes. In men, the age-related shrinkage of the caudate was stronger on the left, whereas, in women, the opposite trend was evident. In both sexes, age-related shrinkage of the right putamen was greater than of its left counterpart. The mild bilateral age-related shrinkage of the globus pallidus was observed only in men. In both sexes, we observed significant rightward asymmetry in the putamen, significant leftward asymmetry in the caudate, and no asymmetry in the globus pallidus. CONCLUSIONS: Bilateral age-related shrinkage of the neostriatum is found in healthy adults. The shrinkage of the globus pallidus is less pronounced and may be restricted to men only.

Neuroanatomical correlates of cognitive aging: evidence from structural magnetic resonance imaging.

To examine putative brain substrates of cognitive functions differentially affected by age the authors measured the volume of cortical regions and performance on tests of executive functions, working memory, explicit memory, and priming in healthy adults (18-77 years old). The results indicate that shrinkage of the prefrontal cortex mediates age-related increases in perseveration. The volume of visual processing areas predicted performance on nonverbal working memory tasks. Contrary to the hypotheses, in the examined age range, the volume of limbic structures was unrelated to any of the cognitive functions; verbal working memory, verbal explicit memory, and verbal priming were independent of cortical volumes. Nevertheless, among the participants aged above 60, reduction in the volume of limbic structures predicted declines in explicit memory. Chronological age adversely influenced all cognitive indices, although its effects on priming were only indirect, mediated by declines in verbal working memory.

Differential effects of age and sex on the cerebellar hemispheres and the vermis: a prospective MR study.

PURPOSE: The purpose of this study was to determine the effects of age and sex on the size of the cerebellar hemispheres, the cerebellar vermis, and the pons in healthy adults. METHODS: We estimated the volumes of the cerebellar hemispheres (excluding the vermis and the peduncles), the cross-sectional area of the vermis, and the cross-sectional area of the ventral pons from MR images obtained in 146 healthy volunteers, 18 to 77 years old. RESULTS: We found a mild but significant age-related reduction in the volume of the cerebellar hemispheres and in the total area of the cerebellar vermis; however, the analysis of age trends in the vermian lobules revealed differential age-related declines. The areas of lobules VI and VII and of the posterior vermian lobules (VIII-X) declined significantly with age, whereas the anterior vermis (I-V) showed no significant age-related shrinkage. The volume of the cerebellar hemispheres (especially the right) and the area of the anterior vermis were greater in men, even after adjustment for height. Neither age nor sex affected the area of the ventral pons. CONCLUSIONS: Normal aging of the cerebellum is associated with selective regional shrinkage. The cerebellar hemispheres and the area of the anterior vermis may be larger in men than in women regardless of differences in body size.

Selective aging of the human cerebral cortex observed in vivo: differential vulnerability of the prefrontal gray matter.

In a prospective cross-sectional study, we used computerized volumetry of magnetic resonance images to examine the patterns of brain aging in 148 healthy volunteers. The most substantial age-related decline was found in the volume of the prefrontal gray matter. Smaller age-related differences were observed in the volume of the fusiform, inferior temporal and superior parietal cortices. The effects of age on the hippocampal formation, the postcentral gyrus, prefrontal white matter and superior parietal white matter were even weaker. No significant age-related differences were observed in the parahippocampal and anterior cingulate gyri, inferior parietal lobule, pericalcarine gray matter, the precentral gray and white matter, postcentral white matter and inferior parietal white matter. The volume of the total brain volume and the hippocampal formation was larger in men than in women even after adjustment for height. Inferior temporal cortex showed steeper aging trend in men. Small but consistent rightward asymmetry was found in the whole cerebral hemispheres, superior parietal, fusiform and orbito-frontal cortices, postcentral and prefrontal white matter. The left side was larger than the right in the dorsolateral prefrontal, parahippocampal, inferior parietal and pericalcarine cortices, and in the parietal white matter. However, there were no significant differences in age trends between the hemispheres.

Age, gender, and hemispheric differences in human striatum: a quantitative review and new data from in vivo MRI morphometry.

We reviewed postmortem and neuroimaging studies of striatal neuroanatomy in humans. The quantitative review revealed evidence of moderate age-related shrinkage of the caudate nucleus and the putamen and consistent leftward asymmetry of the globus pallidus. The data on sex differences were very sparse. We examined neostriatal structures in two samples (healthy volunteers and patients with negative radiological findings) using in vivo magnetic resonance imaging. In both samples, bilateral age-related shrinkage of the caudate nucleus was found, although among the patients the effect was significant only for males. The putamen was measured only in the second sample, and age-related reduction in its volume was found also only among males. A trend for rightward asymmetry in the volume of caudate nucleus was observed in both samples, although it reached statistical significance only among the patients. Putative pathological and physiological mechanisms underlying the observed differences in teh neostriatum are discussed.

Selective neuroanatomic abnormalities in Down's syndrome and their cognitive correlates: evidence from MRI morphometry.

We examined the pattern of neuroanatomic abnormalities in adults with Down's syndrome (DS) and the cognitive correlates of these abnormalities. Specifically, we compared this pattern with what would be predicted by the hypotheses attributing DS pathology to either premature aging or Alzheimer's disease. We measured a number of brain regions on MRIs of 25 subjects: 13 persons with the DS phenotype and 12 age- and sex-matched healthy volunteers. Study participants had no history of cardiovascular disease, diabetes, thyroid dysfunction, or seizure disorder. After statistical adjustment for differences in body size, we found that, in comparison with controls, DS subjects had substantially smaller cerebral and cerebellar hemispheres, ventral pons, mammillary bodies, and hippocampal formations. In the cerebellar vermis of DS subjects, we observed smaller lobules VI to VIII without appreciable differences in other regions. In addition, we noted trends for shrinkage of the dorsolateral prefrontal cortex, anterior cingulate gyrus, inferior temporal and parietal cortices, parietal white matter, and pericalcarine cortex in DS subjects compared with normal controls. The parahippocampal gyrus was larger in DS subjects. We found no significant group differences in the volumes of the prefrontal white matter, the orbitofrontal cortex, the pre- and postcentral gyri, or the basal ganglia. We conclude that the pattern of selective cerebral damage in DS does not clearly fit the predictions of the premature aging or Alzheimer's disease hypotheses. To examine the relationship between brain abnormalities and cognitive deficits observed in DS, we correlated the size of brain regions that were significantly reduced in DS with performance on tests of intelligence and language. The correlation analysis suggested age-related decline in the DS subjects in general intelligence and basic linguistic skills. General intelligence and mastery of linguistic concepts correlated negatively with the volume of the parahippocampal gyrus. There was no relationship between total brain size and the cognitive variables.

Assessment of MR angiography versus arteriography for evaluation of cervical carotid bifurcation disease.

PURPOSE: To assess the accuracy of MR angiography alone in screening for vascular stenosis of the common carotid bifurcation. METHODS: Two hundred two common carotid bifurcations in 101 patients were evaluated with MR angiography and selective contrast arteriography. A two-dimensional time-of-flight pulse sequence was used to obtain sequential transverse images through the common carotid bifurcations. These images were reprojected with a maximum intensity pixel ray-tracing algorithm. Both examinations were blindly graded as either normal or mildly stenotic (0%-29%), moderately stenotic (30%-69%), severely stenotic (70%-99%), or occluded. RESULTS: Of the 202 common carotid bifurcations, 119 were classified as normal-mild stenosis by contrast arteriography. In this category, MR angiography correctly identified 114 of these as normal to mild stenosis. Among 21 common carotid bifurcations graded as moderate stenosis by arteriography, 15 were correctly graded as moderate by MR angiography. Among 45 common carotid bifurcations graded as severe stenosis by arteriography, 41 of these were correctly graded as severe by MR angiography. There were 17 complete occlusions which were all correctly graded by MR angiography. CONCLUSION: MR angiography with its high rate of agreement with contrast arteriography can be regarded as an accurate screening method of the common carotid bifurcation.

Blastomycotic cranial osteomyelitis.

This is the second case report of a temporal bone osteomyelitis caused by Blastomyces dermatitidis, which presented as a chronic serous otitis media. The presenting serous otitis media was refractory to conventional medical and surgical management and progressed to a temporal bone osteomyelitis prior to diagnosis. B. dermatitidis is a rare fungal pathogen that causes a systemic pyogranulomatous disease that primarily manifests itself in the skin, bones, pulmonary, and genitourinary systems. If left untreated it is associated with a high rate of mortality. The otologic presentation of this rare disease is emphasized, while the clinical and therapeutic features are reviewed.

Age-related shrinkage of the mamillary bodies: in vivo MRI evidence.

Mamillary body (MB) is a diencephalic structure hypothesized to be involved in memory, a cognitive function that declines with age. In this study, age-related differences in the size of MB were examined in vivo using magnetic resonance (MR) imaging. The cross-sectional area of the MB was estimated from MR images of the brain in healthy volunteers and neurologically intact patients (age 18-78). The cross-sectional area of the tectum was used as a control region of interest. We found a significant age-related reduction in the area of the MB, but not of the tectum. No sex differences were observed in the size of either structure.

Age-related regional differences in cerebellar vermis observed in vivo.

We investigated age-related differences in the cerebellar vermis. The areas of five vermal regions of interest were estimated from digitized midsagittal magnetic resonance imaging scans of 29 healthy volunteers and 30 neurologically intact patients (aged 18 to 78 years) who were free of vestibular symptoms, seizures, psychosis, or alcoholism. The five regions of interest included the following: (1) lingula and centralis, (2) culmen, (3) declive, folium, and tuber, (4) pyramis, and (5) uvula and nodulus. The ventral pons was used as a control region. After covarying skull size, we found a significant age-related reduction in the total area of the cerebellar vermis. The area of the dorsal regions declined with age, whereas the ventral segments of the vermis--lingula-centralis and uvula-nodulus--showed no significant age-related shrinkage. Notably, the area of the most dorsomedial portion, the declive-folium-tuber, tended to be more strongly associated with age than other segments. The pontine area was unaffected by age. No sex differences were found in the area of the vermis or its subdivisions, but the ventral pontine area was larger in male subjects than in female subjects, even after adjustment for skull size. The mechanisms underlying the observed differences are unclear. It appears, however, that phylogenetically more recent vermal regions, which are late to mature and are endowed with more extensive cortical connections, are the most vulnerable to the effects of aging.

Neonatal nasopharyngeal hairy polyp: CT and MR appearance.

We report a rare tumor of the nasopharynx in the neonate: the teratoid or hairy polyp. In addition to the traditional modes of evaluation (barium swallow, plain radiography, and indirect laryngoscopy), CT and magnetic resonance were used to assess this unusual cause of respiratory distress and vomiting in a newborn.

Infection-related spontaneous atlantoaxial dislocation in an adult. Case report.

This paper reports the third described case of infection-related atlantoaxial subluxation in an adult. Like most of the similar cases seen in the pediatric literature, this case was associated with a parapharyngeal beta-hemolytic streptococcal abscess. Based upon this experience, the authors advocate intravenous antibiotic therapy and 1) immediate reduction followed by application of a halo brace; 2) immobilization in a halo brace for at least 3 months; and 3) a C1-2 wiring and fusion procedure for patients who fail this trial of conservative therapy.

Diagnosis of diseases of the lumbar spine: correlation of computerized tomography with myelography and clinical findings.

Data from 339 patients referred for evaluation of suspected lumbar disease were studied retrospectively to correlate findings in the routine clinical evaluation with results of computed tomography and myelography. Clinical features from the patients' history that correlated with an abnormal CT and myelogram included age greater than or equal to 40, a history of previous surgery, and absence of a history of injury. Signs from the physical examination that correlated included reduced lumbar motion, a motor or sensory deficit, abnormal reflexes, and reduced capacity for straight leg-raising or walking. Using a clinical score incorporating these variables, we suggest a diagnostic strategy to promote more efficient and selective use of CT scans and myelograms. We project that the use of this diagnostic approach can reduce the number of myelograms ordered in a similar population by more than 50%.

Reformatted sagittal images in the differential diagnosis of meningiomas and pituitary adenomas with suprasellar extension.

Approximately 3 to 4 times a year, a tumor with suprasellar extension escapes classification on high resolution coronal and transaxial computed tomography. When arteriography failed to determine the diagnosis, the differential choices were usually meningioma or pituitary adenoma. The authors report the use of sagittal reformatted images in this differential diagnosis and conclude that these images may aid in the distinction between pituitary tumors with suprasellar extension and meningiomas located in this area.

Duplex carotid ultrasound.

Technical advances in the field of ultrasound have resulted in the development of a high resolution real-time B-mode imaging system that permits direct Doppler analysis of hemodynamic abnormalities. This system combines both anatomic information and physiological information which permits detailed analysis of the entire spectrum of disease occurring at the carotid bifurcation. Future developments will permit improved management of patients at risk for stroke from carotid vascular disease.