William L. Hirsch

Aneurysms of the Intracavernous Carotid Artery: Natural History and Indications for Treatment

Of 37 patients with 44 intracavernous carotid artery aneurysms (ICCAAns) diagnosed between 1976 and 1988, patients with 20 aneurysms were followed without treatment for 5 months to 13 years (median, 2.4 years). Ten of the 20 ICCAAns were asymptomatic at diagnosis, and 10 were symptomatic. Three of the asymptomatic ICCAAns were symptomatic at follow-up. One of these required clipping because of a progressing cavernous sinus syndrome; the other 2 were minimally symptomatic and have not required treatment. Of the 10 initially symptomatic ICCAAns, 2 had not changed, 4 became more symptomatic, and 4 had symptomatically improved by follow-up. One patient with an ICCAAn that had not changed clinically was lost to follow-up 6 months after diagnosis. Of the 4 ICCAAns that became more symptomatic, 2 continue to be monitored, and 2 required intervention: one with detachable balloon occlusion of the aneurysm with preservation of the internal carotid artery lumen, and the other with gradual cervical internal carotid artery occlusion. The clinical course of this selected group of patients with ICCAAns suggests that the natural history of ICCAAns can be quite variable. Although clinical progression does occur, symptomatic ICCAAns also can improve spontaneously. Therapeutic intervention for asymptomatic ICCAAns should be reserved for patients with aneurysms arising at the anterior genu of the carotid siphon and/or extending into the subarachnoid space, where subarachnoid hemorrhage is most likely. Intervention for symptomatic ICCAAns should be reserved for patients with subarachnoid hemorrhage, epistaxis, severe facial or orbital pain, evidence of radiographic enlargement, progressive ophthalmoplegia, or progressive visual loss.

Acute Cerebellitis: Case Report and Review

We report a case of acute cerebellitis in a 7-year-old male presenting with headache, vomiting, ataxia and life-threatening hydrocephalus requiring emergent placement of an external ventricular drain. Unlike earlier reported cases which did not provide radiographic correlation of this disease, this report documents changes in the cerebellum with serial magnetic resonance and computer tomography scans. The signs, symptoms and differential diagnosis of this rare, self-limiting condition are briefly discussed.

Chordomas and chondrosarcomas involving the cavernous sinus: Review of surgical treatment and outcome in 31 patients

During the last 9 years, 31 patients with chordomas (20 cases) and chondrosarcomas (11 cases) involving the cavernous sinus have been treated using an aggressive surgical approach. On the basis of postoperative magnetic resonance imaging (MRI), 17 patients were considered to have undergone total removal, whereas in the remaining 14 cases the tumor was either subtotally or partially removed. Surgical complications were most commonly encountered among patients who had undergone previous operations. One patient died 3 months after the operation as a result of pulmonary embolism. Significant disability occurred in one patient because of thalamic perforator occlusion and hemorrhage. Recovery of extraocular muscle function was gratifying, and correlated to the preoperative functional level. After a median follow-up of 24 months, three recurrences (21%) occurred among the 14 patients who had undergone incomplete removal. No recurrence was observed among the 17 patients with total resection. This experience shows that gross radical removal of chordomas and chondrosarcomas involving the cavernous sinus can be accomplished with an acceptable surgical morbidity. However, much longer follow-up will be required to determine whether such aggressive surgical treatment results in cure or long-term control of these neoplasms.

Gliomatosis cerebri: a case report with autopsy correlation

SummaryMRI-autopsy correlation in a case of gliomatosis cerebri suggests that poor gray-white matter demarcation on MRI may be sign of neoplastic infiltration. The extent of infiltration is imperfectly assessed by current imaging modalities.

Eighth nerve signs in a case of multiple sclerosis

We evaluated a 25-year-old woman with multiple sclerosis who presented with the acute onset of a profound unilateral high-frequency, sensorineural hearing loss that resolved clinically within 10 days. Click-elicited brain stem-evoked responses were abnormal at the time of presentation and demonstrated only limited recovery over a follow-up period of 11 months. Magnetic resonance imaging disclosed a lesion in the eighth nerve root-entry zone and the cochlear nucleus. Our findings in this case support the hypothesis of eighth nerve root-entry zone involvement in sudden hearing loss in multiple sclerosis and reinforce the notion that click-elicited brain stem-evoked responses are useful primarily to evaluate the high-frequency regions of the auditory system.

Diagnostic role of gadolinium-DTPA in pediatric neuroradiology

SummaryWe retrospectively reviewed the findings in 655 consecutive young patients who underwent contrastenhanced MR examinations (1.5T) of the head or spine. Their ages ranged from 4 months to 20 years (mean 10 years). There was a 1.7% incidence of minor adverse reactions to gadolinium (Gd)-DTPA, none of which required treatment; no serious adverse reactions were encountered. Based on the radiologic diagnosis the patients were divided into three groups: (1) normal, (2) CNS neoplasm, (3) abnormal but not neoplasm. There were 178 patients thought to have CNS neoplasms and of these 156 (88%) enhanced. Of 124 histologically confirmed neoplasms 115 (93%) showed enhancement after Gd-DTPA. Eight children had histologically confirmed spinal neoplasms; 5 of 6 neurofibromas and 2 ependymomas enhanced. In the 216 patients with abnormalities thought not to be neoplastic, the enhancement rate was 11%; most of the enhancing lesions were vascular malformations. There were very few examples of inflammatory disease, acute trauma or stroke among our patients.

Imaging of Acoustic Neuromas

Diagnosis of acoustic neuromas has been simplified considerably by computed tomography (CT) and magnetic resonance imaging (MRI). Either enhanced method will visualize almost every acoustic neuroma. MRI is more sensitive inside the internal auditory canal. Currently, a gadolinium-enhanced MRI scan is considered an accurate indicator of whether or not an individual has an acoustic neuroma, although there have been false-positive enhanced MRI scans recently reported.

Variability in the enhancement of the normal central skull base in children

SummaryWe studied the signal and enhancement characteristics of the central skull base prospectively in 40 children aged 13 days to 8 years, on a 1.5 T MRI system. Identical standard short TR/TE spin echo sequences in the sagittal plane were performed before and after intravenous gadolinium-DTPA. The sequences used for comparison were filmed at identical window and level settings. Three independent observers assessed (1) the intensity of contrast enhancement of the basisphenoid, basiocciput and presphenoid, (2) the signal intensity of the spheno-occipital synchondrosis, (3) the degree of pneumatization of the sphenoid sinus and (4) the uniformity of signal intensity reflecting fatty replacement of the marrow of the basisphenoid, basiocciput and presphenoid. In 16% and 28% respectively of cases there was no enhancement of the basisphenoid and basiocciput after gadolinium administration; in 42% and 44% there was mild enhancement, and moderate or intense enhancement was observed in 42% and 28% of cases. Even when there was irregular fatty replacement, residual hemopoietic clements could enhance intensely. When skull base neoplasms are being investigated, the normal signal irregularity and enhancement of the central skull base in children must not be confused with pathologic invasion of the marrow.

Postoperative computed tomographic evaluation of patients with large pituitary tumors treated with operative decompression and radiation therapy

Thirty consecutive patients who underwent operative decompression and radiation therapy for large sellar and suprasellar pituitary tumors (greater than or equal to 2 cm) were studied in terms of the serial computed tomographic (CT) changes. There were 23 men and 7 women. The mean age was 49.6 +/- 2.5 years, and the mean follow-up was 45.3 +/- 3.9 months. Twenty-eight of the 30 patients had transsphenoidal surgery, and 27 had hormonally inactive tumors. Radiation therapy was begun within 1 month of surgery with a mean dose of 4855 +/- 70 cGy. Postoperative CT scans were obtained within 1 month of surgery and at 6- to 12-month intervals thereafter. Fourteen patients (45%) had no suprasellar tumor visualized in either the early postoperative CT scans or on subsequent scans. Eleven patients (35%) had a persistent suprasellar mass during the early postoperative period that resolved on serial CT evaluation. The mean time for resolution was 10.4 +/- 1.2 months. Six patients (20%) had a persistent suprasellar mass on serial CT evaluation. A persistent postoperative mass that subsequently resolved in many of the patients was thought to be caused by the gradual retraction of the postoperative packing and hematoma, as well as the effect of radiation on any residual tumor.

Herniated L4-L5 disc after placement of Harrington instrumentation for a fracture of the thoracolumbar spine.

The authors report a case in which L5 radiculopathy developed acutely after surgery for placement of Harrington rod instrumentation for an L1 body fracture. Computed tomographic myelography demonstrated a large L4-L5 herniated disc that had not been present in preoperative studies. An emergency laminectomy was performed, and a large, free, subligamentous disc fragment was removed. The patient subsequently regained L5 sensorimotor function. The postoperative development of lumbar radiculopathy is an uncommon complication of Harrington rod instrumentation that may result from several biomechanical features of the instrumentation. These injuries may not be detected by intraoperative monitoring of somatosensory evoked potentials, and therefore, the postoperative neurological examination assumes a crucial role in the early diagnosis of these lesions. As our case demonstrates, these radicular deficits may be reversible if their cause is promptly recognized and treated.