Intracranial arteriovenous malformations: real-time auto-triggered elliptic centric-ordered 3D gadolinium-enhanced MR angiography--initial assessment.

Auto-triggered elliptic centric-ordered three-dimensional (3D) gadolinium-enhanced magnetic resonance (MR) angiography was compared with 3D multiple overlapping thin-slab acquisition time-of-flight (TOF) MR angiography in the evaluation of intracranial arteriovenous malformations (AVMs) in 10 patients. Intraarterial digital subtraction angiography (DSA) was the reference standard. Gadolinium-enhanced MR angiograms were found to be equivalent to DSA images in AVM component depiction in 70%--90% of cases and were consistently superior to TOF MR angiograms.

Spatial and temporal registration of CT and SPECT images: development and validation of a technique for in vivo three-dimensional semiquantitative analysis of bone.

UNLABELLED: The combined use of postoperative 3-dimensional CT and SPECT imaging provides a means of relating anatomy and physiology for the semiquantitative in vivo analysis of bone. This study focuses on the development and validation of a technique that accomplishes this through the registration of SPECT data to a 3-dimensional volume of interest (VOI) interactively defined on CT images. METHODS: Five human cadaver heads served as anthropomorphic models for all experiments. Four cranial defects were created in each specimen with inlay and onlay split-skull bone grafts reconstructed to skull and malar recipient sites. To acquire all images, each specimen was landmarked with 1.6-mm ball bearings and CT scanned. Bone surfaces were coated with 99mTc-doped paint. The locations of the ball bearings were marked with paint doped with 111In. Separate SPECT scans were acquired using the energy windows of 99mTc and 111In. RESULTS: Serial SPECT images aligned with an average root-mean-square (RMS) error of 3.8 mm (i.e., <1 pixel). CT-to-SPECT volume matching aligned with an RMS error of 7.8 mm. Total counts in CT-defined VOIs applied to SPECT data showed a strong linear correlation (r2 = 0.86) with true counts obtained from a dose calibrator. CONCLUSION: The capability of this multimodality registration technique to anatomically localize and quantify radiotracer uptake is sufficiently accurate to warrant further assessment in an in vivo trial.

Computed tomography artifacts associated with craniofacial fixation devices: an experimental study.

This study compares the artifacts caused by eight different craniofacial fixation devices in computed tomography (CT) images. Using a Teflon CT phantom model, part I of this study involved the quantitative evaluation of the X-ray absorption properties of each fixation device. Part II utilized a human cadaveric model to determine the degree to which the artifact interfered with the visualization of anatomic structures. In part I, each fixation device was secured to the surface of the phantom and then scanned. All artifacts were compared on the basis of standard deviation in CT number. The severity of the artifact was related to the physical size of the fixation device and its composition. Vitallium devices generated a greater degree of CT artifacts than titanium devices of comparable size. In part II, fixation devices were secured to the orbital rims of human cadaveric heads and then scanned. Visualization of specified anatomic structures was graded independently. The results revealed that titanium fixation devices did not cause significant bone or soft-tissue image degradation, whereas all vitallium fixation devices, except micro mesh and micro (1.0 mm) straight plates, generated an artifact that resulted in some image degradation. The extent of image degradation was related to the fixation device size. Only the thickest vitallium fixation device, mini fragmentation (2.0 mm), resulted in bony image degradation. The degree of soft-tissue image degradation decreased as the size of vitallium fixation devices decreased such that micro fragmentation (0.8 mm) and pan fixation (1.3 mm) devices interfered with soft-tissue visualization only in the immediate vicinity of the plate. The results of this study confirm the previous work of Sullivan and colleagues and Fiala and associates. The data indicate that when postoperative imaging is an important clinical consideration: (1) the fewest number of internal fixation devices should be used to achieve rigid bony fixation, (2) the proximity of fixation devices to the regions of interest should be considered at the time of fixation, (3) titanium implants produce less artifacts than vitallium implants of comparable size, and (4) vitallium micro mesh and micro (1.0 mm) straight fixation devices do not produce artifacts resulting in significant image degradation.

Amyotrophic lateral sclerosis: correlation of clinical and MR imaging findings.

PURPOSE: To determine the magnetic resonance (MR) imaging characteristics of amyotrophic lateral sclerosis (ALS) and to evaluate possible correlations between the disease severity and the MR imaging findings. MATERIALS AND METHODS: The authors retrospectively reviewed MR images of the head in 17 patients with ALS (14 men and three women) and 17 age-matched control subjects. The corticospinal tract (CST) was analyzed for the following features: size, signal intensity, and number of sections and regions in which the CST could be seen. RESULTS: Patients with ALS demonstrated sharp, well-defined, round, symmetric lesions that were hyperintense to gray matter within the CST. The lesions were best seen at the level of the middle or lower internal capsule on T2-weighted images. Visualization of the CST on proton-density-weighted images (which occurred in eight ALS patients) is the most reliable MR finding. Low signal intensity was identified within the motor cortex in six patients. Positive MR findings correlated with average or rapid progression of the disease. CONCLUSION: Increased signal intensity in the CST on proton-density-weighted MR images is diagnostic for motor neuron disease and correlates with the rate of disease progression. Subtle ALS changes can be differentiated from the normal CST. Low signal intensity in the motor cortex on T2-weighted images is a useful finding.

A phase I/II study of salvage radiosurgery in the treatment of recurrent brain metastases.

Radiosurgery has been advocated as a salvage treatment for relapsed patients with brain metastases. This report describes a phase I/II study of salvage radiosurgery for patients previously treated with whole brain irradiation. The study was opened in March 1989 and the last patient was treated in July 1992. All patients have been followed to recurrence at the radiosurgically treated site or to death. Twenty progressing metastases in 12 patients were treated using 14 radiosurgical procedures. The radiation dose was always 25 Gy with the 90% isodose volume encompassing all enhancing tumour. Nineteen metastases were evaluable at +4 weeks. There were no instances of progressive disease; there were three complete responses, six partial responses, and 10 metastases remained unchanged. Median survival from the date of radiosurgery was 6 months. Nine of 12 patients eventually failed at the radiosurgically treated site (two remain alive). Radiosurgery at the time of relapse provides temporary control of recurrent brain metastases with acceptable toxicity.

Community care: does it reduce the need for psychiatric beds? A comparison of two different styles of service in three hospitals.

The admission pattern of under-65s during the first seven years of Kidderminster's District General Hospital Psychiatric Department was compared with the last seven years of the mental hospital (Powick Hospital) which it superseded in July 1978, and with its nearest mental hospital (Barnsley Hall Hospital). In Kidderminster the average length of patient's hospital stay was half that at Barnsley Hall. There were more admissions per head of population, more which lasted less than a week, and more patients with over six admissions to Kidderminster than Barnsley Hall. The retrospective comparison with Powick Hospital showed that these differences were not due to the superior community facilities in Kidderminster since there was no real change in hospital bed use with the development of community services; this supports the view that there is a bed-rock of illness which will always need in-patient care however comprehensive the community resources.

Older volunteers: a discussion of the Minnesota Senior Study.

We used findings from the Minnesota Senior Study to examine the theoretical and methodological difficulties of defining, coding, and analyzing data on older volunteers. This study, the first statewide survey of the needs and resources of the elderly in Minnesota in almost 20 years, found that over half (52%) of older Minnesotans do volunteer work for organizations--considerably higher than has been found in national surveys. Problems in definition and methodology, however, have confounded analyses. This paper proposes a new conceptual model for classifying volunteer roles, based on three dimensions: whether the voluntary service is "formal" or "informal"; whether the activity entails a regular or an occasional time commitment; and the nature of the service activity (person-to-community, person-to-object, or person-to-person).

Psychological, topographic EEG, and CT scan correlates of frontal lobe function in schizophrenia.

This study examined frontal lobe function in a group of 20 patients with schizophrenia, on and off medication, compared to 20 normals matched for age, sex, handedness, intelligence, and educational level. Schizophrenic patients generally did not perform as well as normals on the Wisconsin Card Sorting Test (WCST). Patients off medication performed less well on this test than those on medication. Those on medication did not perform as well as those off medication on the design and word fluency tests, which suggested that medications may affect various aspects of frontal lobe function differently. During the WCST, normal subjects demonstrated an increase in beta mean frequency of the electroencephalogram in frontal and centrotemporal regions which was not statistically significant in either schizophrenic group. This shift in beta mean frequency was found to correlate positively with performance on the WCST in normals, but not in patients. Patients with more negative symptoms tended to show a smaller increase in beta mean frequency during the WCST. Performance on the WCST was correlated negatively with ventricle-brain ratio in all subjects, suggesting that frontal lobe function might be related to computed tomographic measures in the normal population as well as in schizophrenic patients. There was no correlation with performance on the WCST and length of illness.

Isolated basilar artery occlusion associated with a clivus fracture.

Most vascular injuries to the brain secondary to blunt head trauma involve the internal carotid circulation. A case of isolated basilar occlusion secondary to a clival fracture is described and compared to three other cases in the literature.

The radiology of sacral cysts.

The radiological findings in 10 patients with sacral cysts were retrospectively reviewed and classified. The cysts were an incidental finding on computed tomography (CT) in four patients. The expansion of sacral foramina or the sacral canal as seen on plain films suggested the diagnosis in three. In only two of the five patients who had myelograms did the cysts fill with contrast. In eight, CT showed remodelling and expansion of the sacral foramina, or the canal, or both, by a homogeneous mass with a density of 5-20 Hounsfield units. One of the patients underwent magnetic resonance imaging which confirmed that the lesion was fluid-filled. We found that sacral cysts can be either symptomatic or asymptomatic, that they may or may not communicate with the subarachnoid space, and that they have a characteristic CT appearance.

Computed tomography of lingual thyroid.

The CT findings of a lingual thyroid are presented. A round, well-defined, homogeneously enhancing mass at the base of the tongue suggested the diagnosis leading to the confirmatory isotope scan.

Epidermoid tumor: an unusual cause of ossification within the spinal canal.

Epidermoid tumors of the spinal canal are rare. We report two patients with intraspinal lesions and radiographically evident calcification. One proved to have an epidermoid tumor. Although the tissue diagnosis in the second was not definitive, it suggested an epidermoid tumor as well. Radiographically visible ossification or calcification has not been reported before in intraspinal epidermoids.

Radiologic assessment of acoustic neuroma in the elderly. Is no treatment good treatment?

Twenty-three elderly patients with acoustic neuroma have been followed conservatively (no treatment) for a mean of 3.8 years. Five patients subsequently required ventricular shunting. Two patients required partial excision of their tumors (one previously treated by shunting). Eleven patients who have required no treatment have no significant complaints. There was significant variation in tumor growth rates making predictability for surgical intervention hazardous. A mean growth rate of 0.22 cm/year was noted. Our statistics suggest tumor removal in healthy patients with larger tumors at time of presentation; in other patients, conservative follow-up may be more appropriate.

CT of myeloma involving the skull base.

We report three patients with myeloma involving the skull base. A large extracranial soft-tissue mass, intracranial extension, homogeneous enhancement, smooth margins, and bone remodelling were features common to the three lesions. In two patients the lesions extended into the orbit with one patient presenting with proptosis.

The choana and nasal obstruction.

A subject with a septal perforation was studied rhinometrically to confirm that the congested choana did not limit airflow when the anterior nose was decongested. It did not. This suggests that in an undefined proportion of patients with swollen diseased mucosa, surgery to the anterior nose may be sufficient to relieve nasal obstruction.

Adenoid cystic carcinoma: an unusual neurosurgical entity.

Adenoid cystic carcinoma, or cylindroma, usually presents in the salivary glands or in the upper respiratory passages. We report an unusual case of adenoid cystic carcinoma in a 45-year-old woman who presented with a three-year history of progressive right trigeminal sensory palsy, most pronounced in the second division. There was, in addition, a right trigeminal motor palsy and a partial right 6th nerve palsy. CT scanning showed only a small soft tissue mass spanning an enlarged right foramen ovale. Solid adenoid cystic carcinoma was resected from Meckel's cave via a middle cranial fossa approach. A subsequent biopsy of the right maxillary antral mucosa found tumor tissue. We concluded that the tumor originated in the maxillary antrum and spread posteriorly along the infraorbital nerve to enlarge in the foramen ovale. Radiation to a total of 5,000 cGy was given. At 22 months there was neither radiographic nor clinical evidence of recurrence. At 30 months, the development of unsteady gait signalled the presence of recurrent tumor extending backwards from Meckel's cave into the right cerebello-pontine angle.

The role of primary bone grafting in complex craniomaxillofacial trauma.

The role of craniofacial surgical techniques and immediate bone grafting in the management of complex craniofacial trauma has been reviewed. Four hundred and one patients with complex facial injuries have been treated. Two hundred and forty-one primary bone and cartilage grafts have been performed in 66 patients. Complex facial injuries should be managed by direct exposure, reduction, and fixation of all fractures utilizing interfragmentary wiring. Very comminuted or absent bone is replaced by immediate bone grafting, producing a stable skeleton without the need for external fixation devices. Associated mandibular fractures are managed with rigid internal fixation utilizing A-O technique. Results of immediate bone grafting have been excellent, and complications are rare. All deformities should be corrected, whenever possible, during the initial operation. This one-stage reconstruction of even the most complex facial injuries will prevent severe postoperative traumatic deformity and disability that may be extremely difficult or impossible to correct secondarily.

Neurologic complications associated with gold therapy for rheumatoid arthritis.

Neurologic complications of gold are rare and include peripheral neuropathy, a Guillain-Barré-type syndrome, cranial nerve palsies and encephalopathy. Three cases of cranial neuropathy complicating chrysotherapy for rheumatoid arthritis are described. One also had a sensorimotor neuropathy associated with segmental demyelination and axonal degeneration, and another developed an encephalopathy which, on contrast enhanced computed tomographic scanning, showed reversible cerebral and cerebellar white matter lesions. Early recognition and prompt withdrawal of chrysotherapy are the mainstay of management of this lesser known complication.