Massive symptomatic subependymoma of the lateral ventricles: case report and review of the literature

Subependymomas are benign intraventricular tumors with an indolent growth pattern, which are usually asymptomatic, and most commonly occur in the fourth and lateral ventricles. When symptomatic, subependymomas often obstruct critical portions of the cerebrospinal fluid (CSF) pathway, causing hydrocephalus, and range from 3 cm to 5 cm in size. We report a case of an unusually massive subependymoma of the lateral ventricles treated with subtotal resection, ventriculoperitoneal shunt, and post-surgical radiation. The clinical course, radiographic and pathologic characteristics of this massive intraventricular subependymoma are discussed, as well as the differential diagnosis of lateral ventricular masses and a review of the literature concerning subependymomas.

Common errors in the use of magnetic resonance imaging for neuro-ophthalmic diagnosis

The optimal utilization of magnetic resonance imaging in neuro-ophthalmic diagnosis is limited by errors in prescribing and interpreting scans. In a review of case material, we discovered four common prescriptive errors: 1) failure to apply a dedicated study, 2) inappropriate use of a dedicated study, 3) omission of intravenous contrast, and 4) omission of specialized sequences. The four common interpretive errors were the following: 1) failure to detect the lesion because of misleading clinical information, 2) rejection of a clinical diagnosis because an expected imaging abnormality was absent, 3) assumption that a striking imaging abnormality accounted for the clinical abnormality, and 4) failure to consider the lack of clinical specificity of imaging abnormalities. Many of these errors could be avoided by improved communication between clinicians and radiologists.

Audiovestibular phenotype associated with a COL11A1 mutation in Marshall syndrome

BACKGROUND

Marshall syndrome is a dominant disorder characterized by craniofacial and skeletal abnormalities, sensorineural hearing loss, myopia, and cataracts, and is associated with splicing mutations in COL11A1.

OBJECTIVE

To determine the auditory and vestibular phenotypes associated with a COL11A1 splicing.

DESIGN

Clinical otolaryngologic, audiologic, vestibular, and radiologic evaluations of the auditory and vestibular systems.

SUBJECTS

Three affected individuals from a family cosegregating Marshall syndrome and a COL11A1 splice site mutation.

RESULTS

The study subjects have progressive sensorineural hearing loss that is predominantly cochlear in origin and asymptomatic dysfunction of the central and peripheral vestibular systems. Computed tomography detected no malformations of temporal bone structures.

CONCLUSIONS

The observed auditory and vestibular abnormalities are not caused by defective morphogenesis of the osseous labyrinth, but by more direct effects of the COL11A1 mutation on the membranous labyrinth and the central nervous system. The onset and degree of hearing loss associated with COL11A1 mutations are useful clinical features to differentiate Marshall syndrome from the phenotypically similar Stickler syndrome.

Decrease in cortisol reverses human hippocampal atrophy following treatment of Cushing's disease

BACKGROUND

Decreased hippocampal volume is observed in patients with Cushing's syndrome and other conditions associated with elevated cortisol levels, stress, or both. Reversibility of hippocampal neuronal atrophy resulting from stress occurs in animals. Our study investigated the potential for reversibility of human hippocampal atrophy.

METHODS

The study included 22 patients with Cushing's disease. Magnetic resonance brain imaging was performed prior to transsphenoidal microadenomectomy and again after treatment.

RESULTS

Following treatment, hippocampal formation volume (HFV) increased by up to 10%. The mean percent change (3.2 +/- 2.5) was significantly greater (p < .04) than that of the comparison structure, caudate head volume (1.5 +/- 3.4). Increase in HFV was significantly associated with magnitude of decrease in urinary free cortisol (r = -.61, p < .01). This relationship strengthened after adjustments for age, duration of disease, and months elapsed since surgery (r = -.70, p < .001). There was no significant correlation between caudate head volume change and magnitude of cortisol decrease.

CONCLUSIONS

Changes in human HFV associated with sustained hypercortisolemia are reversible, at least in part, once cortisol levels decrease. While many brain regions are likely affected by hypercortisolemia, the human hippocampus exhibits increased sensitivity to cortisol, affecting both volume loss and recovery.

Metastatic adenocarcinoma to the brain mimicking hemorrhage: case report

BACKGROUND

Computerized tomography (CT) of metastatic adenocarcinoma to the brain usually shows low-to-moderate attenuation. However, mucinous adenomas may appear with high attenuation, mimicking hemorrhage.

CASE DESCRIPTION

A 68-year-old man with a history of metastatic esophageal adenocarcinoma presented to the emergency room complaining of a chronic, progressive right occipital headache. A head CT demonstrated a moderate-to-high attenuation, homogenous mass in the right cerebellar hemisphere consistent with an intracerebral hemorrhage. There was no frank calcification in the mass by CT criteria. An emergent posterior fossa craniectomy revealed nonhemorrhagic metastatic mucinous adenocarcinoma.

CONCLUSION

Moderate-to-high attenuation, noncalcified brain masses should raise the possibility of mucin-containing neoplasm.

Patterns of failure following high-dose 3-D conformal radiotherapy for high-grade astrocytomas: a quantitative dosimetric study

PURPOSE

To analyze the failure patterns for patients with high-grade astrocytomas treated with high-dose conformal radiotherapy (CRT) using a quantitative technique to calculate the dose received by the CT- or MR-defined recurrence volume and to assess whether the final target volume margin used in the present dose escalation study requires redefinition before further escalation.

METHODS AND MATERIALS

Between 4/89 and 10/95, 71 patients with high-grade supratentorial astrocytomas were entered in a phase I/II dose escalation study using 3-D treatment planning and conformal radiotherapy. All patients were treated to either 70 or 80 Gy in conventional daily fractions of 1.8-2.0 Gy. The clinical and planning target volumes (CTV, PTV) consisted of successively smaller volumes with the final PTV defined as the enhancing lesion plus 0.5 cm margin. As of 10/95, 47 patients have CT or MR evidence of disease recurrence/progression. Of the 47 patients, 36 scans obtained at the time of recurrence were entered into the 3-D radiation therapy treatment planning system. After definition of the recurrent tumor volumes, the recurrence scan dataset was registered with the pretreatment CT dataset so that the actual dose received by the recurrent tumor volumes during treatment could be accurately calculated and then analyzed dosimetrically using dose-volume histograms. Recurrences were divided into several categories: 1) "central," in which 95% or more of the recurrent tumor volume (Vrecur) was within D95, the region treated to high dose (95% of the prescription dose); 2) "in-field," in which 80% or more of Vrecur was within the D95 isodose surface; 3) "marginal," when between 20 and 80% of Vrecur was inside the D95 surface; 4) "outside," in which less than 20% of Vrecur was inside the D95 surface.

RESULTS

In 29 of 36 patients, a solitary lesion was seen on recurrence scans. Of the 29 solitary recurrences, 26 were central, 3 were marginal, and none were outside. Multiple recurrent lesions were seen in seven patients: three patients had multiple central and/or in-field lesions only, three patients had central and/or in-field lesions with additional small marginal or outside lesions, and one patent had 6 outside and one central lesion. Since total recurrence volume was used in the final analysis, 6 of the 7 patients with multiple recurrent lesions were classified into centra/in-field category.

CONCLUSION

Analysis of the 36 evaluable patients has shown that 32 of 36 patients (89%) failed with central or in-field recurrences, 3/36 (8%) had a significant marginal component to the recurrence, whereas only 1/36 (3%) could be clearly labeled as failing mainly outside the high-dose region. Seven patients had multiple recurrences, but only 1 of 7 had large-volume recurrences outside the high-dose region. This study shows that the great majority of patient recurrences that occur after high-dose (70 or 80 Gy) conformal irradiation are centrally located: only 1/36 patients (with 7 recurrent lesions) had more than 50% of the recurrence volume outside the region previously treated to high dose. Further dose escalation to 90 Gy (and beyond) thus seems reasonable, based on the same target volume definition criteria

Familial Mondini dysplasia

OBJECTIVES/HYPOTHESIS

To determine the mode of inheritance of familial nonsyndromic Mondini dysplasia.

STUDY DESIGN

Correlative clinical genetic analysis of a single kindred.

METHODS

Clinical history, physical examination, audiologic analysis, computed tomography of the temporal bones, and cytogenetic analysis.

RESULTS

The male proband, three affected sisters, and an affected brother are offspring of unaffected parents. The mother and an unaffected brother have audiologic findings suggestive of heterozygous carrier status for a recessive hearing loss gene.

CONCLUSIONS

Pedigree analysis indicates autosomal recessive inheritance in this family. The observed inheritance and clinical, audiologic, and radiologic findings are different from those previously described for another family with nonsyndromic Mondini dysplasia. The phenotype in this study family therefore represents a distinct subtype, indicating clinical and genetic heterogeneity of this disorder. This information should facilitate future molecular linkage analyses and genetic counselling of patients with inner ear malformations.

Parotid gland sparing in patients undergoing bilateral head and neck irradiation: techniques and early results

PURPOSE

To minimize xerostomia in patients receiving bilateral head and neck irradiation (RT) by using conformal RT planning to spare a significant volume of one parotid gland from radiation.

METHODS AND MATERIALS

The study involved 15 patients with head and neck tumors in whom bilateral neck radiation was indicated. The major salivary glands and the targets (tumor, surgical bed, metastases to lymph nodes, and the locations of lymph nodes at risk for metastases) were outlined on axial computed tomography images. Beam's-eye view (BEV) displays were used to construct conformal beams that delivered the prescribed doses to the targets while sparing from direct radiation most of one parotid gland. The gland that was planned to be spared resided in the neck side that was judged in each patient to be at a lesser risk of metastatic disease. Major salivary gland flow rates and the responses to a subjective xerostomia questionnaire were assessed before, during, and after radiation.

RESULTS

Radiation planning for patients with central oropharyngeal tumors required the generation of multiple axial nonopposed beams. The resulting isodoses encompassed the targets, including the retropharyngeal nodes and the jugular nodes up to the base of skull bilaterally, while limiting the dose to the oral cavity, spinal cord, and one parotid gland. For patients with lateralized tumors, the ipsilateral neck side was treated up to the base of the skull; in the contralateral neck side, the treatment included the subdigastric nodes but excluded the jugular nodes at the base of the skull and most of the parotid gland. This was accomplished by a moderate gantry angle that was chosen using the BEV displays. Three months following the completion of radiation, the spared parotid glands retained on average 50% of their unstimulated and stimulated flows. In contrast, no saliva flow was measured from the unspared glands in any of the patients. Subjective xerostomia was absent, mild, or not different from that reported before radiation in 10 of 15 patients (67%).

CONCLUSION

Partial parotid gland sparing is feasible by using three-dimensional planning in patients undergoing bilateral head and neck radiation. Approximately 50% of the saliva flow from the spared glands may be retained, and most patients thus treated have no or mild xerostomia in the early period after the completion of radiation. Whether tumor control and late complications are comparable to standard radiation will be assessed as more experience is gained.

Familial large vestibular aqueduct syndrome

The large vestibular aqueduct syndrome (LVAS) is a distinct clinical entity characterized by stepwise progressive sensorineural hearing loss associated with isolated enlargement of the vestibular aqueduct. A correlative clinical, audiologic, vestibular, cytogenetic, and radiographic analysis of a family with inherited LVAS was performed. The male proband and his affected brother are offspring of unaffected parents, and have no other abnormalities. Pedigree analysis suggests autosomal recessive or X-linked inheritance with variable expressivity of LVAS in this family. This study is the first description of familial inheritance of LVAS. LVAS may account for a significant number of patients with nonsyndromal, genetic sensorineural hearing loss. Future molecular analyses of this study family may identify the causative gene(s) in LVAS.

Foramen magnum neurenteric cyst causing mollaret meningitis: MR findings

MR showed a neurenteric cyst posterior to the cervicomedullary junction in a man with chronic recurrent aseptic meningitis. On T1-weighted MR, the cyst was of high intensity in relation to the brain, and on T2-weighted MR it was of less intensity than cerebrospinal fluid.

Imaging of normal leptomeningeal melanin

PURPOSE

To find CT and MR characteristics of normal leptomeningeal melanin, which can be macroscopically visible at autopsy in decedents with deeply pigmented skin.

METHODS

For the normal anatomic study, there were two black subjects who had brain MR and CT within 12 months before autopsy that showed leptomeningeal melanin. For the normal imaging study, brain MR was done on 74 patients (31 black), and CT in 24 of these 74 patients.

RESULTS

In the normal anatomic study, the pattern of T2-weighted hypointensities on the surface of the medulla oblongata matched the histopathologic distribution of leptomeningeal melanin. A similar signal was seen in 28 of the 31 black patients in the normal imaging study. Such a signal was subtle, or entirely absent, in the other patients. CT showed no reliable altered attenuation corresponding to the histopathologic distribution of leptomeningeal melanin.

CONCLUSION

Normal leptomeningeal melanin is visible on MR as T2-weighted hypointensities along the surface of the medulla oblongata. The signal changes can be profound and might simulate leptomeningeal diseases that contain melanin or iron. This normal pigmentation should be taken into account before diagnosing abnormalities in this region.

Painful oculomotor palsy caused by posterior-draining dural carotid cavernous fistulas

BACKGROUND

Carotid cavernous fistulas cause conjunctival hyperemia and orbital soft-tissue swelling because of increased flow directed anteriorly in ophthalmic veins. Less well recognized is that when fistular flow is directed posteriorly, these congestive features will be absent and the diagnosis of the "white-eyed shunt" will be missed unless angiography is performed.

METHODS

Two patients who had oculomotor nerve palsies caused by posteriorly draining dural carotid cavernous fistulas were studied, and the 28 previously described cases were reviewed.

RESULTS

One patient had a chronic painful palsy of the sixth cranial nerve, and the other, a palsy of the third cranial nerve. Cerebral angiography disclosed the fistulas. The clinical and imaging features of these cases conform to those of the 28 previously reported white-eyed shunts. Angiographic features do not explain why some posterior-draining fistulas cause sixth-nerve palsies and others cause third- (or rarely, fourth-) nerve palsies.

CONCLUSIONS

Dural carotid cavernous fistulas that drain primarily into the inferior petrosal sinus may cause painful oculomotor palsies that elude diagnosis because they lack congestive orbito-ocular features. Treatment by embolization leads to more rapid resolution of manifestations.

Inferior petrosal sinus: imaging-anatomic correlation

PURPOSE

To correlate computed tomographic (CT) or magnetic resonance (MR) images with dissections of normal inferior petrosal sinuses (IPS).

MATERIALS AND METHODS

Postmortem dissection was performed in 12 individuals, one of whom had undergone CT and MR imaging 3 months before death. Seven patients underwent IPS venography, CT, and MR imaging. One hundred sixteen patients with normal IPS underwent MR imaging; 40, CT and MR imaging; and two, CT, MR imaging, and arteriography.

RESULTS

Images showed that the IPS and basilar plexus formed conspicuous, enhanced structures that provide much of the border between the clivus and cerebrospinal fluid. Axial, cross-sectional IPS dimensions were as large as 9 x 16 mm. The larger sinuses were contained by deep grooves of bone that sometimes showed marked cortical thinning. Sixty-nine (39%) of the 175 individuals studied had markedly asymmetric IPS.

CONCLUSION

CT and MR images showed that normal IPS and basilar plexus vary in size and are frequently asymmetric. This range of normal measurements and appearances should be taken into account before abnormalities in this region are diagnosed.

Structural and functional brain imaging in Friedreich's ataxia

BACKGROUND

Although the major neuropathologic changes in Friedreich's ataxia (FA) affect the spinal cord and peripheral nerves, we previously found abnormally increased glucose metabolism in the cerebral hemispheres in ambulatory patients and a return toward normal metabolism in nonambulatory patients.

OBJECTIVE

To determine whether brain atrophy accompanies the decline in cerebral glucose metabolism in FA and whether the degree of atrophy and the extent of decline in cerebral glucose metabolism are related to clinical severity.

DESIGN

Prospective series.

SETTING

University referral center.

PATIENTS

Twenty-two patients with FA and 26 patients with dizziness, headache, or minor acute head trauma, serving as control subjects, who underwent computed tomographic scans that were interpreted as normal.

MEASURES

In patients with FA and control subjects, regional atrophy was assessed using subjective and objective measures on computed tomographic scans. In patients with FA, local cerebral glucose metabolism was measured with positron emission tomography, and clinical severity was assessed with a clinical rating scale.

RESULTS

Atrophy in the cerebral hemispheres, cerebellum, and brain stem was significantly greater in patients with FA than in control subjects, and the degree of atrophy correlated with the clinical severity. Local cerebral metabolic rate for glucose declined significantly from the initially elevated levels in the thalamus, cerebellum, and brain stem in correlation with increasing clinical severity.

CONCLUSIONS

The structure and function of wide-spread brain regions including the cerebral hemispheres are abnormal in FA, and these abnormalities correlate with the clinical severity.

Cerebellopontine angle invasive papillary cystadenoma of endolymphatic sac origin with temporal bone involvement

The authors report the MR, CT, and pathologic findings in a case of invasive papillary cystadenoma originating in the endolymphatic sac and involving the temporal bone. This case illustrates characteristic imaging features of this lesion. The authors emphasize awareness of this entity with its aggressive temporal bone involvement as an aid to pathologic differential diagnosis.

The cochlear nuclear complex: MR location and abnormalities

PURPOSE

To determine the usefulness of MR imaging in locating known structural landmarks of the cochlear nuclear complex (CNC), and to determine the frequency of CNC abnormalities, based on these landmarks, in patients referred for MR evaluation of unilateral sensorineural hearing loss.

SUBJECTS AND METHODS

We studied 12 consecutive months of temporal bone/posterior fossa MR images retrospectively to find four known structural landmarks of the CNC: the vestibulocochlear nerve root entry zone; the cerebellar flocculus; the curvilinear choroid plexus along and protruding from the foramen of Luschka; and the bulge of the CNC into the lateral recess of the fourth ventricle and the foramen of Luschka. We tabulated the number of landmarks located per CNC and the number and type of CNC MR abnormalities. Medical records were then reviewed to tabulate clinical indication for MR imaging, type of hearing deficit, and etiology of the hearing deficit and clinical-pathologic proof.

RESULTS

175 patients (ages 15-75 years) provided 350 CNCs for study. All 350 CNCs showed at least three of the four landmarks. Thirteen of the 175 patients (7.4%) had focal CNC MR abnormalities; 136 of these 175 patients had been referred for MR evaluation of unilateral sensorineural hearing loss. In 10 of these 136 patients (7.4%), the CNC abnormalities shown on MR proved to be the cause of the sensorineural hearing loss.

CONCLUSIONS

MR reliably delineates the CNC. Over 1 year, approximately 7% of patients referred for MR evaluation of unilateral sensorineural hearing loss had MR-determined focal CNC abnormalities that caused the sensorineural hearing loss.

Stereotactic localization using fast spin-echo imaging in functional disorders

Fast Spin-Echo Magnetic Resonance Imaging facilitates multiplanar target and trajectory selection in functional disorders by rapidly delineating gray matter, white matter, vascular, and ventricular structures. Errors due to anatomic variation or co-existing lesions can be avoided as are movement artifacts. Although not a substitute for physiologic target corroboration, the method facilitates safety and efficacy of "functional" stereotactic procedures.

Radiation-induced optic neuropathy: correlation of MR imaging and radiation dosimetry

The authors performed topographic correlation of dosimetric measurements with contrast medium-enhanced magnetic resonance (MR) imaging signal aberration in two cases of radiation optic neuropathy. The region of pathologic contrast enhancement in the optic nerve and chiasm had received 55-62 Gy, which supports the theory that the risk of injury to the optic nerve and chiasm increases steeply with radiation doses above the tolerance level of 50-55 Gy.

Hippocampal formation volume, memory dysfunction, and cortisol levels in patients with Cushing's syndrome

Patients with chronic hypercortisolemia due to Cushing's syndrome (CS) exhibit cognitive dysfunction. Because glucocorticoid excess is associated with hippocampal damage in animals, and the hippocampus participates in learning and memory, we explored the relationships between hippocampal formation (HF) volume, memory dysfunction, and cortisol levels in 12 patients with CS. After magnetic resonance imaging, HF volume was determined using digital sum of track ball traces of dentate gyrus, hippocampus proper and subiculum, correcting for total intracranial volume. For 27% of the patients, HF volume fell outside the 95% confidence intervals for normal subject volume given in the literature. In addition, there were significant and specific correlations between HF volume and scores for verbal paired associate learning, verbal recall, and verbal recall corrected for full-scale IQ (r = 0.57 to 0.70, p < 0.05). HF volume was negatively correlated with plasma cortisol levels (r = -0.73, p < 0.05). These studies suggest an association between reduced HF volume, memory dysfunction, and elevated cortisol in patients with CS.

Enhancement along the normal facial nerve in the facial canal: MR imaging and anatomic correlation

Normal facial nerves are reported to show no enhancement at magnetic resonance (MR) imaging, in contradiction to the authors' clinical experience. To investigate this inconsistency, the authors searched MR imaging files and clinical records to find patients who underwent MR imaging of the temporal bone (at 1.5 T) before and after intravenous administration of gadopentetate dimeglumine and who had bilateral clinically normal facial nerves. When the MR images of 93 patients (186 facial nerves) were analyzed subjectively, 142 nerves (76%) were visibly enhanced along at least one segment of the facial nerve within the facial canal; the nerves of 64 of the 93 patients (69%) showed right-left asymmetry in enhancement, which was inhomogeneously distributed along each nerve. The facial nerve in the cerebellopontine angle cistern and in the internal auditory canal, as well as in the visualized proximal portion of the extracranial facial nerve, showed no enhancement. Comparison with reference anatomic sections showed that this enhancement pattern corresponded exactly to the topography of the circumneural facial arteriovenous plexus and should not necessarily be considered a sign of anatomic abnormality.

Visual loss in tuberous sclerosis

Of 11 patients with tuberous sclerosis complex (TSC) treated from 1980 to 1990 for obstructive hydrocephalus secondary to subependymal giant-cell astrocytoma, four had adequate documentation to determine visual outcome. Despite surgical relief of elevated intracranial pressure in all cases, two patients sustained further visual loss. In one patient, visual loss was arrested, and in one patient, it was prevented. Although hydrocephalus is uncommon in TSC, its effects on the optic nerves are serious and eventually irreversible. Because TSC patients may not be able to express early symptoms of increased intracranial pressure, periodic ophthalmologic examination and brain imaging may be advisable when a subependymal lesion has been identified.

Nystagmus of Pelizaeus-Merzbacher disease. A magnetic search-coil study

Magnetic search-coil oculography of three brothers with clinically diagnosed Pelizaeus-Merzbacher disease disclosed the presence of binocular elliptical pendular nystagmus in two patients in whom the waveform of the nystagmus was not obvious on inspection. This study, the first reported application of high-resolution oculography to Pelizaeus-Merzbacher disease, also demonstrated primary position upbeat nystagmus in all three patients. The importance of finding this combination of elliptical pendular and upbeat nystagmus is that it is not described in any other childhood neurodegenerative states and, in combination with supportive clinical history and magnetic resonance imaging, may be so characteristic of Pelizaeus-Merzbacher disease that a strong presumptive diagnosis can be made.

Three-dimensional x-ray computed tomography of the temporal bone as an aid to surgical planning

Three-dimensional x-ray computed tomography (3DCT) has been useful in planning surgical procedures involving craniofacial reconstruction, the pelvis, hip, spine, knee and shoulder. The clinical use of 3DCT in temporal bone surgery has not been evaluated. We used 3DCT to assess temporal bone anatomy in 9 patients. These cases evaluated two encephaloceles, two postinflammatory dehiscences, two temporal bone fractures, one glomus jugulare tumor, one acoustic neuroma, and one meningioma. We found 3DCT useful in these temporal bone applications as a supplement to standard two-dimensional CT scanning (2DCT). While 3DCT provided a better preoperative understanding of the underlying anatomy, no treatment was modified solely on the basis of the information derived from the 3-D presentation of data. We conclude that, although 3DCT images have some qualitative advantages over 2DCT techniques, their value in further defining temporal bone morphology must be evaluated against the cost entailed by their use.

The Marinesco-Sjögren syndrome examined by computed tomography, magnetic resonance, and 18F-2-fluoro-2-deoxy-D-glucose and positron emission tomography

The Marinesco-Sjögren syndrome is an autosomal recessive degenerative disorder characterized by congenital cataracts, cerebellar ataxia, spasticity, mental deficiency, and skeletal abnormalities. We studied two adult siblings with Marinesco-Sjögren syndrome using anatomic and metabolic brain imaging techniques to characterize the pattern and nature of abnormalities in the brain. Computed tomographic and magnetic resonance imaging showed diffuse brain atrophy of mild to moderate degree, involving primarily the white matter of the cerebrum, cerebellum, brain stem, and cervical spinal cord. The pattern of atrophy resembled that seen in diffuse leukoencephalopathies. Measurements of local cerebral glucose metabolic rates with positron emission tomography revealed no statistically significant differences from normal control subjects in most regions, but metabolic rate was decreased in the thalamus in one patient. The findings support a diffuse white matter disorder in Marinesco-Sjögren syndrome.

Intra-arterial bromodeoxyuridine radiosensitization of malignant gliomas

In the 1950's it was first observed that mammalian cells exposed to the halogenated deoxyuridines were more sensitive to ultraviolet light and radiation than untreated cells. This prompted early clinical trials with bromodeoxyuridine (BUdR) which showed mixed results. More recently, several Phase I studies, while establishing the feasibility of continuous intravenous (IV) infusion of BUdR, have reported significant dose limiting skin and bone marrow toxicities and have questioned the optimal method of BUdR delivery. To exploit the high mitotic activity of malignant gliomas relative to surrounding normal brain tissue, we have developed a permanently implantable infusion pump system for safe, continuous intraarterial (IA) internal carotid BUdR delivery. Since July 1985, 23 patients with malignant brain tumors (18 grade 4, 5 grade 3) have been treated in a Phase I clinical trial using IA BUdR (400-600 mg/m2/day X 8 1/2 weeks) and focal external beam radiotherapy (59.4 Gy at 1.8 Gy/day in 6 1/2 weeks). Following initial biopsy/surgery the infusion pump system was implanted; BUdR infusion began 2 weeks prior to and continued throughout the 6 1/2 week course of radiotherapy. There have been no vascular complications. Side-effects in all patients have included varying degrees of anorexia, fatigue, ipsilateral forehead dermatitis, blepharitis, and conjunctivitis. Myelosuppression requiring dose reduction occurred in one patient. An overall Kaplan-Meier estimated median survival of 20 months has been achieved. As in larger controlled series, histologic grade and age are prognostically significant. We have shown in a Phase I study that IA BUdR radiosensitization is safe, tolerable, may lead to improved survival, and appears to be an efficacious primary treatment of malignant gliomas.

MR imaging of the brain in five members of a family with Pelizaeus-Merzbacher disease

MR imaging was performed in five members of a family afflicted with Pelizaeus-Merzbacher disease. The individuals imaged included a male proband, his mother, and three maternal uncles. Clinically affected members showed generalized white matter signal aberration consistent with dys- and demyelination, basal ganglia, and thalamic signal aberration suggestive of pathologic iron storage and diffuse brain atrophy. These findings are similar to those seen in other leukodystrophies. The proband's mother was normal by neurologic examination but showed a suspicious but not definitely abnormal similar pattern of basal ganglionic and white matter signal aberration. In our limited patient sample, MR appears to be able to: (1) demonstrate a pattern of imaging abnormalities characteristic of Pelizaeus-Merzbacher disease (we do not know if this pattern is specific); (2) potentially detect the obligate carrier state; and (3) detect the facultative carrier state.

Cranial lymphangiomatosis causing CSF otorrhea and recurrent meningitis: CT features

We present a case of cranial lymphangiomatosis that resulted in CSF leakage through the ear and recurrent meningitis. The plain radiographic findings, CT, and CT cisternographic appearances are discussed along with a brief review of the literature.

Visual outcome in cystic craniopharyngiomas treated with intracavitary phosphorus-32

Seven patients with cystic craniopharyngiomas were treated with stereotactic instillation of radioactive phosphorus-32 (32P). Five patients had been previously treated with various combinations of surgery and external beam irradiation, whereas two had the 32P instillation at a primary therapy. Visual acuity improved in 13 eyes and remained stable in 1. Visual fields normalized in three patients, improved in two, and remained stable in two. Two patients received single treatments with 32P, whereas five required multiple instillations for recurrent cyst expansion.

Optic tract injury after anterior temporal lobectomy

Three patients had complete homonymous hemianopia with clinical and neuroimaging characteristics of ipsilateral optic tract infarction after anterior temporal lobectomy for seizure control. This injury presumably resulted from irritative vasospasm of the anterior choroidal artery. The features of this pure optic tract syndrome should be distinguished from the more common compressive optic tract syndrome which generally also impairs ipsilateral optic nerve function.

CT demonstration of cavernous sinus fat

CT demonstration of cavernous sinus fat deposits has been described as abnormal and potentially a specific sign of Cushing disease. CT scans of 100 patients without biochemical or clinical evidence of Cushing disease and of 10 patients with Cushing disease were studied retrospectively. Twenty-seven percent of the non-Cushing patients demonstrated fat in one or both cavernous sinuses. Forty percent of Cushing disease patients had detectable cavernous sinus fat. While fat deposits were more frequent in the Cushing disease group, this was not statistically significant (p = greater than .6). CT demonstration of cavernous sinus fat ordinarily should be regarded as a normal finding.

Atlanto-axial rotational limitation secondary to osteoid osteoma of the axis. Case report

An unusual case of atlanto-axial rotational limitation secondary to an osteoid osteoma of the axis is presented. Transoral microsurgical resection followed by physical therapy improved the clinical symptoms. This case illustrates several unique problems within the cervical spine as well as the efficacy of the transoral approach to the axis.

Idiopathic intracranial hypertension (pseudotumor cerebri): MR imaging

Magnetic resonance (MR) imaging was performed on six patients with idiopathic intracranial hypertension (IIH). The patients were all women with a mean age of 27 years (range, 17-41 years). Six healthy women volunteers with a mean age of 33 years (range, 25-46 years) were studied for comparison. All six patients had elevated opening pressures at lumbar puncture. MR imaging demonstrated a partially empty sella in two patients, and one patient had signal aberration in the dural venous sinuses suggestive of slow flow. There were no white matter signal abnormalities, even in the periependymal space. Volumetric pixel analysis revealed significantly larger subarachnoid space volumes in patients than in control subjects, without a significant difference in ventricular volumes. No other intracranial abnormalities were found in any IIH patient or control subject. The results suggest that, in IIH, (a) although the subarachnoid spaces are enlarged, the wide range of normal values would limit the clinical use of these measurements and (b) the role of MR imaging, as with CT, is primarily in the exclusion of other diseases with clinical presentations similar to that of IIH.

Intra-arterial 5-bromo-2-deoxyuridine (BUdR) radiosensitization with external beam radiation in rhesus monkeys: toxicity study

A primate toxicity study was performed to test the hypothesis that BUdR does not increase the likelihood of unilateral or bilateral central nervous system damage secondary to radiation therapy. BUdR, a halogenated pyrimidine analog is incorporated into DNA of dividing cells and sensitizes them to radiation. It is best given unilaterally, intra-arterially by continuous infusion because of its regional advantage (Rd) estimated to be between 11 and 16. Six rhesus monkeys were implanted with a Model 400 Infusaid pump perfusing the right internal carotid artery. Three of the six monkeys received intra-arterial (IA) BUdR infusion plus whole brain external beam radiation (6,000 R over 6 weeks) and three received radiation alone. The two BUdR treated animals completing radiation developed symmetric bilateral high signal aberrations on MRI in the frontal, parietal, and occipital centrum semiovale and corona radiata at nine months. At autopsy, confluent microinfarcts were found to correspond topographically to the MRI abnormalities. In the radiation alone group, two animals had normal MRI and autopsy while the third animal had bilateral MRI high signal aberrations develop sequentially with corresponding microinfarcts at autopsy. These changes were greater in severity than those seen in the BUdR treated animals. We support previous evidence that there is differential intraspecies sensitivity to radiation. We find that BUdR produces no unilateral potentiation of radiation toxicity.

Preoperative treatment of acromegaly with long-acting somatostatin analog SMS 201-995: shrinkage of invasive pituitary macroadenomas and improved surgical remission rate

Ten patients with previously untreated acromegaly and invasive pituitary macroadenomas were treated with the long-acting somatostatin analog SMS 201-995 (Sandoz) for 3-30 weeks before transsphenoidal or subfrontal pituitary adenomectomy. Preoperatively, treatment with SMS 201-995 reduced mean 24-h plasma GH concentrations from 8.5-66.7 to below 4.6 micrograms/L in eight patients and by 60-80% in the remaining two patients. Pituitary tumor size decreased 20-54%. Morphologically, the tumors showed decreased total cell, cytoplasmic, and nuclear areas; varying degrees of perivascular fibrosis; and dense granularity. Postoperatively, plasma GH and insulin-like growth factor I concentrations fell into the normal range, and GH dynamics became normal in eight patients. In the remaining two patients mild GH hypersecretion persisted after surgery (mean fasting and random plasma GH, 6.1 and 7.9 micrograms/L), and in one of them GH secretion became normal 1 yr after pituitary irradiation. Thus, preoperative administration of SMS 201-995 consistently induced shrinkage of GH-producing pituitary tumors, and the apparent remission rate was high in the treated patients.

Intra-arterial bromodeoxyuridine radiosensitization and radiation in treatment of malignant astrocytomas

Bromodeoxyuridine (BUdR), a nonhypoxic radiosensitizing drug, is a halogenated pyrimidine analog that is incorporated into the deoxyribonucleic acid of dividing cells in a competitive process with thymidine; BUdR also sensitizes these cells to radiation therapy. Neurons and glial cells have a very low mitotic rate. They will not incorporate BUdR and will not be sensitized. Bromodeoxyuridine is best delivered intra-arterially because of its regional advantage, calculated to be between 6 and 16. An 8-week BUdR infusion is delivered before and during radiation therapy through a permanently implanted pump with a catheter placed retrograde into the external carotid artery. Eighteen patients with malignant glioma (15 grade IV, and three grade III) were entered into a Phase I dose-escalation protocol with BUdR dosages ranging from 400 to 600 mg/sq m/day. The maximum dose that can be tolerated appears to be 400 mg/sq m/day for 8 weeks. The 18 patients entered in this study have a median Kaplan-Meier estimated survival time (+/- standard error of the mean) of 22 +/- 5 months with 11 patients still alive. Three patients are alive at 30, 29, and 21 months after diagnosis with no evidence of tumor on computerized tomography. There have been no vascular complications. Side effects in all patients have included anorexia, fatigue, ipsilateral forehead dermatitis, blepharitis, iritis, and nail ridging. Myelosuppression requiring dose reduction occurred in one patient. One patient had a Stevens-Johnson syndrome requiring termination of BUdR. It is concluded that intra-arterial BUdR may improve survival times in patients with malignant gliomas.

Motor dysfunction in olivopontocerebellar atrophy is related to cerebral metabolic rate studied with positron emission tomography

We compared the severity of motor dysfunction with local cerebral metabolic rates for glucose (lCMRGlc) and the degree of tissue atrophy in 30 patients with olivopontocerebellar atrophy (OPCA). We devised a scale to quantitate the degree of ataxia in the neurological examinations. lCMRGlc was measured with 18F-2-fluoro-2-deoxy-D-glucose and positron emission tomography (PET). Tissue atrophy was assessed by visual rating of computed tomographic scans. PET studies revealed marked hypometabolism in the cerebellar vermis, cerebellar hemispheres, and brainstem of OPCA patients compared with 30 control subjects. A significant correlation was found between severity of motor impairment and lCMRGlc within the cerebellar vermis, both cerebellar hemispheres, and the brainstem. A significant but weaker relationship was noted between the degree of tissue atrophy in these regions and clinical severity. Partial correlation analysis revealed that motor dysfunction in OPCA correlated more strongly with lCMRGlc than with the amount of tissue atrophy. These results suggest that the clinical manifestations of OPCA are more closely related to the metabolic state of the tissue than to the structural changes in the cerebellum.

Cerebellar and brainstem hypometabolism in olivopontocerebellar atrophy detected with positron emission tomography

We studied local cerebral metabolic rates for glucose (1CMRglc) with 18F-2-fluoro-2-deoxy-D-glucose and positron emission tomography (PET) in 30 patients with olivopontocerebellar atrophy (OPCA) and 30 age-matched control subjects without neurological disease. The diagnosis of OPCA was based on the history and physical findings and on the exclusion of other causes of cerebellar ataxia by means of laboratory investigations. Computed tomographic scans revealed some degree of atrophy of the cerebellum in most patients with OPCA, and many also had atrophy of the brainstem. PET studies in these patients revealed significant hypometabolism in the cerebellar hemispheres, cerebellar vermis, and brainstem in comparison with the normal control subjects. A significant relationship was found between the degree of atrophy and the level of 1CMRglc in the cerebellum and brainstem. Nevertheless, several patients had minimal atrophy and substantially reduced 1CMRglc, suggesting that atrophy does not fully account for the finding of hypometabolism. 1CMRglc was within normal limits for the thalamus and cerebral cortex. The data suggest that PET/1CMRglc may be useful as a diagnostic test in patients with the adult onset of cerebellar ataxia.

MR imaging of Pelizaeus-Merzbacher disease

Pelizaeus-Merzbacher disease (PMD) is a rare, slowly progressive, sex-linked demyelinating disorder generally classified with the sudanophilic leukodystrophies. The onset is most often in the pediatric age group and may be diagnosed as cerebral palsy because of the subtle onset. Cranial magnetic resonance (MR) imaging of two patients with PMD showed reversal of the normal gray/white matter signal relationships, consistent with dysmyelination, as well as low intensity lentiform nuclei and thalami possibly suggesting pathologic iron deposition. Magnetic resonance also better demonstrated low volume brain without the beam hardening limitations of X-ray CT. Although our MR findings correlate well with the pathophysiology of PMD, the MR characteristics are not specific. The diagnosis of PMD remains one of clinical and laboratory exclusion.