Effects of age on dopamine and serotonin receptors measured by positron tomography in the living human brain.

D2 dopamine and S2 serotonin receptors were imaged and measured in healthy human subjects by positron emission tomography after intravenous injection of 11C-labeled 3-N-methylspiperone. Levels of receptor in the caudate nucleus, putamen, and frontal cerebral cortex declined over the age span studied (19 to 73 years). The decline in D2 receptor in males was different from that in females.

Pediatric metrizamide CT cisternography: cerebrospinal fluid circulation and hydrocephalus.

The technique of intrathecal enhancement using metrizamide (Amipaque) combined with CT imaging enables both the morphologic and dynamic (serial) evaluation of the intracranial cerebrospinal fluid pathways. Three distinct metrizamide CT cisternographic patterns (delayed, intermediate, and normal) emerge in pediatric patients with hydrocephalus. The findings correlate well with radionuclide cisternographic patterns; however, CT also provides excellent morphologic definition.

Anti-Ro(SS-A) autoantibodies in central nervous system disease associated with Sjögren's syndrome (CNS-SS): clinical, neuroimaging, and angiographic correlates.

OBJECTIVE: To examine in Sjögren's syndrome (SS) the interrelationship between the presence of the anti-Ro(SS-A) antibody response and (1) concomitant presence and type (ie, focal or nonfocal) of CNS disease (CNS-SS), (2) cross-sectional brain MRI or CT, and (3) abnormal cerebral angiography. METHODS: Neurologic, neuroimaging, and angiographic features of CNS-SS patients were correlated with the presence of precipitating anti-Ro(SS-A) autoantibodies detected by gel double-immunodiffusion or quantitative ELISA, which detects antibodies directed against the 60-kd peptide. Statistical analyses were performed using Fisher's exact test (two-tailed) with Haldane's adjustment and odds ratio with Cornfield 95% confidence intervals. RESULTS: Precipitating antibodies against the Ro(SS-A) antigen, determined by gel double-immunodiffusion, were present in an increased frequency in CNS-SS patients with (1) documented clinical CNS disease, (2) focal clinical CNS manifestations and serious complications, (3) large regions of increased signal intensity, consistent with ischemia/infarcts on brain MRI scans or regions of decreased attenuation consistent with infarcts on CT, and (4) abnormal cerebral angiograms consistent with small-vessel angiitis. Finally, the anti-Ro(SS-A) antibody response in CNS was directed against the 60-kd peptide specificity, determined by ELISA. CONCLUSIONS: Clinical, neuroimaging (cerebral CT), and angiographic observation suggest that a subset of anti-Ro(SS-A) antibody-positive, in contrast with -negative, CNS-SS patients have more serious and extensive CNS disease, some with frank cerebral angiopathy. Anti-Ro(SS-A) antibodies are postulated to play a role in mediating or potentiating vascular injury in CNS-SS.

Nuclear magnetic resonance and gamma camera tumor imaging using gadolinium-labeled monoclonal antibodies.

Chelate-derivatized monoclonal antibody labeled with paramagnetic gadolinium-3+ ion has been evaluated as a tumor-specific contrast-enhancing agent in nuclear magnetic resonance imaging in the Rauscher murine erythroleukemia system. With 10(-7) M concentrations of Gd3+ delivered to the tumor target, a small but reproducible difference in proton relaxation times (T1S) was observed in excised tumors. Nuclear magnetic resonance imaging of animals, however, failed to show significant contrast enhancement of the tumor; by comparison, gamma camera images with 153Gd-labeled specific antibody did permit clear tumor visualization without subtraction. The potential use of monoclonal antibodies in tumor imaging appears to be far greater in gamma camera and positron imaging than in nuclear magnetic resonance imaging.

The adrenoleukodystrophies.

Clinical, biochemical, and genetic studies of adrenoleukodystrophy (ALD) are of current interest for six main reasons. First, assays of plasma lipids or cultured skin fibroblasts or amniocytes permit precise diagnosis of persons affected by the disease, as well as prenatal diagnosis and carrier detection. Second, the general nature of the enzymatic defect has been identified and the ALD gene has been mapped to the q28 segment of the X-chromosome. Third, the disease is more common than had been previously recognized. We have identified 350 patients in over 200 kindreds. Fourth, phenotypic variability is a striking feature. The illness may present as a rapidly fatal neurological disorder in early childhood or as a chronic progressive paraparesis in young, middle-aged, or even older adults. The latter syndrome is referred to as adrenomyeloneuropathy (AMN). It is of particular interest that these variants occur regularly within the same kindred, so that the phenotypic variation cannot be attributed to different genetic mutations. A fifth feature of interest is that in this X-linked disorder 12 to 40% of female carriers show various degrees of neurological disability, although almost always milder than in the hemizygous male. Studies with cultured fibroblasts suggest that mutant ALD cell lines have a competitive advantage over normal cell lines, a phenomenon which has not been observed in any other disorder. Finally, ALD appears to be one example of a peroxisomal disorder. Knowledge about the normal function of this subcellular organelle has emerged only recently, and further studies of ALD and related disorders will contribute to this.

The effect of computed tomographic scan orientation on information loss in the three-dimensional reconstruction of tripod zygomatic fractures.

Fractures modeled in the dried skull indicate that the initial plane of computed tomography (CT) section contributes to the accuracy of three-dimensional (3D) images generated from two-dimensional (2D) CT data. The authors retrospectively analyzed seven clinical cases of tripod zygomatic fractures that were imaged with both axial and coronal CT scan orientations. Ten observers evaluated paired 3D CT images, one generated from 2D CT data in the axial plane and the other generated from coronal 2D CT data, for each of the seven cases of tripod fractures. A G-E 9800 CT scanner with the 3D98 Quick processing system were used for the 3D reconstructions. The axial scan orientation resulted in 3D reconstructions that had significantly less information loss in the display of the tripod fractures than did those based on coronal CT data (P less than .025).

Comparative cranial CT enhancement in the normal primate.

The application of intravenous, intrathecal, and inhalation enhancement techniques to the CT evaluation of the nonhuman primate (Papio cynocephalus/anubis) is described. The falx cerebri cortical vasculature, vein of Galen, straight sinus and tentorium cerebelli were defined with intravenous enhancement. Intrathecal CT enhancement with air was limited by distortion in cerebrospinal fluid spaces. Intrathecal CT enhancement using a low dose of metrizamide accurately delineated the subarachnoid spaces and the brain substance they surrounded with minimal morbidity. Symmetrical brain enhancement (perfusion) was prominent following inhalation CT enhancement; the degree of enhancement correlated with the estimated xenon concentration in the bloodstream. In addition, by performing repeated CT scans during the clearance of xenon from the brain, an approximate analysis of regional cerebral blood flow was obtained.

Apical optic nerve compression of dysthyroid optic neuropathy on computed tomography.

Computed assisted tomography (CT) of seven cases of dysthyroid optic neuropathy showed moderate to severe thickening of the extraocular muscles at the orbital apex, white CT of two control cases of dysthyroid orbitopathy without neuropathy showed minimal or fusiform thickening. The consequences include probable apical compression with optic nerve neuropathy either by direct pressure on the nerve or its blood supply. The management of these cases is either by oral administration of corticosteroids in high dosage with gradual tapering or radiation therapy to the orbital apex (approximately 3,000 rad over a ten-day period). If surgical decompression is to be attempted, it should be designed to decompress the optic nerve at the orbital apex.

Computed tomographic three-dimensional localization and compositional evaluation of intraocular and orbital foreign bodies.

A software program designed for the Siemens Somatom DR3 computed tomographic (CT) scanner provides improved diagnosis, localization, and etiologic description of intraocular and orbital foreign bodies. The program allows information to be analyzed in two different display formats. One format is that of multiplanar reconstruction of the eye and orbit, including an "oblique CT cube" image. This format produces an accurate "three-dimensional" display of both in vitro and in vivo intraocular and orbital foreign bodies. The second display format is that of a histogram. Using this analytic mode, nonmetallic intraocular and intraorbital foreign bodies can be differentiated from each other and from metallic foreign bodies, although individual metallic foreign bodies cannot be identified with respect to specific composition. The information provided by these two display formats substantially aids the clinician in the diagnosis and management of foreign bodies located within the orbit, particularly those located within the eye.

Use of muscle functional magnetic resonance imaging with older individuals.

Muscle functional magnetic resonance imaging (mfMRI) has been widely used to study muscle recruitment in exercise in young healthy subjects, but has not been validated or used with older subjects. This study validates and demonstrates the use of mfMRI in older subjects. Subjects consisted of apparently healthy sedentary younger (n = 7) and older (n = 6) women. Proton transverse relaxation (T2)-weighted MRI scans were obtained of the quadriceps femoris at rest and immediately following three bouts of knee extension exercise (50%, 75%, and 100% of untrained 5 x 10 repetition maximum [RM]). Older subjects performed knee extension training for 12 weeks and repeated the MRI scan protocol using the same absolute loads. Training induced a 13% increase in 1 RM and a 25% increase in 5 x 10 RM. Older subjects had higher resting T2 values compared with younger subjects; however, the T2 response to exercise (slope) was similar among groups (young = 0.063+/-0.003, older untrained = 0.055+/-0.011, older trained = 0.053+/-0.008; p > .05). In all cases, T2 increased linearly with load. Trained older subjects showed a lower T2 response when lifting the same absolute load compared with before training, which is consistent with results previously obtained from young subjects. In the older population, mfMRI is appropriate for use and offers benefits over other technologies.

Resistance training reduces susceptibility to eccentric exercise-induced muscle dysfunction in older women.

This study evaluated the effect of age on susceptibility to muscular weakness and damage caused by eccentric (ECC) exercise and determined whether this susceptibility was altered by resistance training. Young and older women performed concentric (CON) and ECC one repetition maximum (1 RM) strength tests of the quadriceps femoris. Older women also performed knee extension training for 12 weeks. An unaccustomed bout of ECC knee extension exercise was performed before and after training, and CON and ECC 1 RM were reassessed for 11 days after the ECC bout. Magnetic resonance imaging was used to evaluate changes in muscle water content associated with muscle damage. Before training, older subjects showed a larger decline in CON (p =.008) and ECC (p =.03) strength induced by the unaccustomed ECC bout, compared with the young subjects. One day following the ECC bout, the older women showed a 24% reduction in CON and a 27% reduction in ECC 1 RM, compared with only 6% (CON) and 10% (ECC) in the younger women. A magnetic resonance imaging evaluation indicated that edema or damage was significantly greater in the older untrained women than it was in young women (p <.05), but the resistance-trained older women showed no greater muscle injury than the young women (p >.05). Resistance-trained older women showed no greater decline than sedentary young women in either CON (p >.05) or ECC (p >.05) strength. In conclusion, sedentary older women are more susceptible to ECC-induced muscle dysfunction, but resistance training reduces this susceptibility.

Microsurgical removal of a primary intraorbital meningioma.

A 48-year-old woman with a primary intraorbital meningioma associated with the optic nerve sheath underwent a microsurgical removal of the tumor through a lateral orbitotomy. Visual recovery was essentially complete.

Traumatic aneurysms of cavernous internal carotid artery with secondary epistaxis.

The syndrome of delayed epistaxis and monocular blindness following nonpenetrating head injury is reviewed. Bleeding results from rupture of a traumatic cavernous internal carotid artery aneurysm into the sphenoid sinus. There were 96 patients with this syndrome found in the literature and another four are added in this report. In 73% of the patients, the cause of the epistaxis was not appreciated until 4 months after the initial episode. No antemortem diagnosis was made in 15% of the patients. More frequent use of carotid angiography in patients with posttraumatic mononuclear blindness and delayed epistaxis might help reduce the reported mortality of 30%.

Unruptured intracranial arteriovenous malformations do cause mass effect.

Sixty patients with clinically unruptured intracranial arteriovenous malformations were studied with high-resolution computed tomography. In 33, local and distant mass effects were evidenced by compression, distortion, and displacement of normal anatomic structures by the malformation, its afferent and efferent vessels, and the surrounding edema.

The significance of asymmetry of the foramen of Vesalius.

The foramen of Vesalius is a small, variable but consistently symmetrical structure located anteromedial to the foramen ovale and lateral to the foramen rotundum and vidian canal. It transmits an emissary vein through which the cavernous sinus and pterygoid plexus communicate. Fifty high-resolution CT scans of the skull base and two three-dimensional (Cemax) reconstructions were reviewed to determine criteria for defining the normal appearance of the foramen of Vesalius. Three normal types were classified: (1) a well-formed foramen, 1-2 mm in size (n = 32); (2) lack of visualization of the foramen (n = 11); and (3) partial assimilation of the foramen with the foramen ovale (n = 7). The foramen was remarkably symmetric in a large number of cases (n = 48). Asymmetry signified abnormality in four of the six cases. Abnormal causes of asymmetry included invasion by nasopharyngeal melanoma, angiofibroma, carotid cavernous fistula with drainage through the emissary vein, and neurofibromatosis. Thus, for these usually symmetric foramina of Vesalius, asymmetry is more likely the result of a pathologic process than a normal variant.

Facial trauma and 3-D reconstructive imaging: insufficiencies and correctives.

PURPOSE: To address the clinical relevance of and optimal technique for 3-D CT imaging of facial trauma. METHODS: Bioengineered cadaveric models were developed to enhance the concepts of LeFort. Diverse CT imaging techniques were applied to obtain optimal data sets for processing on various 3-D workstations. The fidelity of the 3-D reconstructions was determined by comparison with photographs of the cadaveric models. Optimized 3-D images were then used in conjunction with the initial 2-D data sets to assess whether additional accuracy was contributed by the 3-D images in the evaluation of modeled facial fractures. RESULTS: Image definition was heavily dependent upon the specific 3-D reconstruction algorithm and the processor utilized. Orbital fractures were best imaged when 1- to 1.5-mm coronal sections were processed on an advanced 3-D workstation. The 3-D CT images resulted in additional accuracy in the 2-D CT evaluation of facial fractures in 29% of trials. CONCLUSIONS: We believe that bioengineered models of facial trauma--matched with appropriate CT scanning parameters--facilitate graphically reliable 3-D reconstructive imaging. 3-D reconstructions can improve accuracy in the 2-D CT evaluation of facial trauma.

Giant cervical epidural veins after craniectomy for head trauma.

Markedly dilated cervical epidural veins and right upper extremity weakness developed in a 43-year-old man 4 months after contralateral craniectomy for head trauma. After cranioplasty, his symptoms improved markedly and the size of the veins returned to normal. These findings suggest that enlarged cervical epidural veins may occur without an underlying vascular lesion and that upper extremity weakness may occasionally be attributable to spinal cord venous stasis.

Assessing whether the plane of section on CT affects accuracy in demonstrating facial fractures in 3-D reconstruction when using a dried skull.

CT slice thickness and threshold value are well-known determinants of accuracy in three-dimensional (3-D) CT image reconstruction. The purpose of this study was to assess whether the plane selected for primary CT data acquisition, axial vs coronal, might also contribute to the accuracy and ease of identification of abnormalities in 3-D image reconstruction independent of the 3-D processing system used. Two sets of 10 observers evaluated fractures created in a dried skull and corresponding 3-D image data. A General Electric 9800 scanner was used to acquire the two-dimensional CT data. The 3D98 Quick software and ISG Camra Allegra workstation were used for two sets of 3-D reconstructions. The expected result was that fractures oriented perpendicularly to the initial plane of CT section would be better reconstructed on 3-D than when the initial plane of CT imaging paralleled the fracture. Our results indicate that Le Fort fractures (types I and III) are better displayed with coronal CT data and that zygomatic tripod fractures may be better displayed in 3-D with axial CT image data.

Craniocervical junction venous anatomy on enhanced MR images: the suboccipital cavernous sinus.

BACKGROUND AND PURPOSE: The suboccipital cavernous sinus, a vertebral venous plexus surrounding the horizontal portion of the vertebral artery at the skull base, provides an alternative pathway of cranial venous drainage by virtue of its connections to the cranial dural sinuses, the vertebral venous plexus, and the jugular venous system. Knowledge of the anatomy of this system facilitates interpretation of images and might reduce the number of false-positive diagnoses of lesions, such as adenopathy or schwannoma. We hypothesized that this circulation could be visualized on contrast-enhanced, fat-suppressed T1-weighted MR images. METHODS: The craniocervical junctions of 14 patients were scanned using fat-suppressed, contrast-enhanced, T1-weighted MR sequences and evaluated for visibility of the following venous structures: suboccipital cavernous sinus, vertebral artery venous plexus, anterior and posterior condylar veins, vertebral venous plexus, internal jugular vein, and the marginal sinus. Both the right and left sides were assessed in at least two planes. The venous diameters were also measured. RESULTS: All the evaluated venous structures were seen routinely in all three planes, with the exception of the posterior condylar vein, known to be variably present, which was seen only one third of the time in the sagittal plane and two thirds of the time in the other planes. The posterior condylar vein also showed the greatest variability in size and symmetry. CONCLUSION: The suboccipital cavernous sinus and most of its associated venous circulation at the skull base are easily identified on contrast-enhanced, fat-suppressed T1-weighted MR images. The posterior condylar vein, known to be variably present, was not well seen in the sagittal plane and displayed the greatest variability in size and symmetry.

Self-induced ethmoidectomy from rhinotillexomania.

A 53-year-old woman with a long history of compulsive nose picking (rhinotillexomania) presented with a large, self-inflicted nasal septal perforation and right-sided penetration of the ethmoidal sinus, or "ethmoidectomy."