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Biomedical subjects

J L Weissman

Publications and source records attributed to J L Weissman.

At least 37 records · Page 2Linked to original sources
PubMed1997

Neurilemomas of the parapharyngeal space.

OBJECTIVE: To review the surgical management of neurilemomas of the parapharyngeal space (PPS). DESIGN: Retrospective survey of the clinical presentation, radiological features, surgical approaches, surgical findings, and postoperative neurological sequelae of neurilemomas of the PPS. SETTING: Academic tertiary care head and neck referral center. PATIENTS: Fourteen patients with neurilemomas of the PPS, 12 were in the poststyloid compartment. INTERVENTIONS: Preoperative evaluation with computed tomography and/or magnetic resonance imaging with or without angiography. Surgical resection was performed through a transcervical approach. MAIN OUTCOME MEASURES: Radiological features, adequacy of surgical approach, and neurological sequelae of surgery. RESULTS: Radiological studies could distinguish prestyloid from poststyloid tumors and, with poststyloid tumors, can usually differentiate between glomus tumor and neurilemoma. The transcervical approach permitted adequate surgical access. Five of the tumors in the poststyloid space were neurilomomas originating from the sympathetic nervous system, and all 5 patients with these tumors developed Horner syndrome postoperatively. CONCLUSIONS: Computed tomographic and/or magnetic resonance studies should be routinely obtained to evaluate tumors of the PPS, but angiography is indicated only in selected cases. Both prestyloid and poststyloid neurilemomas can be resected through a transcervical approach. Resection of neurilemomas has an attendant risk for neurological dysfunction.

Adult↗
PubMed1997

Papillary endolymphatic sac tumors: CT, MR imaging, and angiographic findings in 20 patients.

PURPOSE: To determine the computed tomographic (CT), magnetic resonance (MR) imaging, and angiographic findings of papillary endolymphatic sac tumors. MATERIALS AND METHODS: Clinical and imaging studies in 20 patients (aged 17-65 years) with histopathologically proved papillary endolymphatic sac tumors were retrospectively reviewed. Patients underwent CT (n = 18), MR imaging (n = 15), or angiography (n = 12). CT scans were evaluated for bone erosion and calcification; MR images, for signal intensity, enhancement patterns, and flow voids; and angiograms, for tumoral blood supply. RESULTS: All tumors were destructive and contained calcifications centered in the retrolabyrinthine region at CT. The MR imaging appearance varied with lesion size; 12 of 15 tumors showed increased signal intensity at T1-weighted imaging. The high-signal-intensity area was circumferential in lesions 3 cm or smaller and was scattered throughout the lesion in advanced tumors. Only tumors larger than 2 cm had flow voids. The blood supply arose predominantly from the external carotid artery. Large tumors had additional supply from the internal carotid and posterior circulation. CONCLUSION: Papillary endolymphatic sac tumors are destructive, hypervascular lesions that arise from the temporal bone retrolabyrinthine region. Increased signal intensity at unenhanced T1-weighted MR imaging is common and may help distinguish these lesions from more common, aggressive temporal bone tumors.

Adenocarcinoma↗
PubMed1997

The evolving MR appearance of structures in the internal auditory canal after removal of an acoustic neuroma.

PURPOSE: To identify patterns of enhancement in the internal auditory canal (IAC) on MR studies after removal of an acoustic neuroma, including changes in those patterns with time; to evaluate signal and enhancement of the labyrinth; to differentiate normal postoperative findings from those suggesting residual tumor; and to describe MR hallmarks of surgical approaches. METHODS: We reviewed the postoperative MR studies obtained in 36 patients who had had surgery for acoustic neuroma (101 images total). Four patterns of IAC enhancement were evaluated, as was labyrinthine signal intensity before and after contrast administration, changes in findings over time, and anatomic alterations caused by surgery. RESULTS: All patients had enhancement of the IAC on the first postoperative study. In 30 patients, IAC enhancement remained the same or decreased over time. Seventeen patients had hyperintense cochlear signal and 15 had cochlear enhancement that decreased with time. Effects of retrosigmoid craniotomy, a translabyrinthine surgical approach, and middle fossa craniotomy were recognizable. CONCLUSION: Linear enhancement in the IAC is probably normal after surgery. Nodular and masslike enhancement and any progressive enhancement may require close follow-up to monitor growth of residual tumor. Labyrinthine hyperintensity may reflect blood metabolites. An MR protocol is suggested for following up patients in the years after surgery.

Adolescent↗
PubMed1997

MR appearance of trigeminal and hypoglossal motor denervation.

PURPOSE: To illustrate and describe the appearance of both long-standing and relatively recently occurring motor denervation of the hypoglossal nerve and of the third (mandibular) division of the trigeminal nerve (V3), with emphasis on findings particular to MR imaging. METHODS: Findings from 11 patients with V3 denervation and from seven patients with hypoglossal denervation resulting from a variety of abnormalities were reviewed retrospectively. The motor denervation appearance and functional compromise of the affected musculature are described in terms of the chronicity of the denervation process. RESULTS: The appearance of V3 and hypoglossal motor denervation varies with the chronicity of the process. Long-standing denervation results in extensive fatty replacement and a decrease in the size of the affected musculature. Relatively recently occurring denervation results in abnormal contrast enhancement and edemalike signal changes in the denervated musculature. Fatty replacement was observed acutely in hypoglossal denervation but did not manifest until the subacute stage in V3 denervation. Increased volume of the denervated musculature may also accompany acute denervation signal changes. CONCLUSION: V3 and hypoglossal denervation have a variable appearance depending on the chronicity of the process. Recognition of MR imaging patterns of denervation may allow earlier diagnosis of a denervating lesion and may help to distinguish denervation from similar-appearing processes, such as infection or neoplasia.

Adipose Tissue↗
PubMed1997

Imaging of Meniere's disease.

The role of CT and MR studies in the evaluation of patients with Meniere's disease is to exclude other pathologic conditions that could masquerade as Meniere's disease clinically. This article is divided into three sections corresponding to the three major symptoms of Meniere's disease. Each section presents examples of CT and MR pathologic conditions that could mimic these clinical findings: "sensorineural hearing loss" covers acoustic neuromas and other cerebellopontine angle tumors, inner ear anomalies, otosclerosis, and more; "vertigo" includes examples of labyrinthitis, endolymphatic sac tumor, cholesteatomatous fistula, and brain metastasis; and "tinnitus" emphasizes causes of nonpulsatile tinnitus and briefly mentions pulsatile tinnitus. Each section also discusses which imaging study best addresses these specific clinical questions.

Hearing Loss, Sensorineural↗
PubMed1996

Chondrosarcoma of the nasal septum: skull base imaging and clinicopathologic correlation.

Chondrosarcoma arising in the head and neck and craniofacial region is an uncommon lesion. The nasal septum is a particularly rare site of origin, with approximately 30 cases previously reported in the English literature. We present six new cases of chondrosarcoma arising in the nasal septum. Each of these tumors required cranial base surgical approaches for removal. Current imaging techniques allow a very accurate diagnosis to be made before biopsy. The characteristic ring-forming calcifications seen on computed tomography scans can be correlated with the histologic pattern of calcification. Magnetic resonance imaging techniques allow precise definition of tumor extent, which is particularly important because the disease is best treated with primary surgery. Advances in imaging and surgical techniques allow a much more complete tumor removal. It is hoped that this will increase the likelihood of cure in these patients. Surgical management and indications for adjuvant therapy are discussed.

Adult↗
PubMed1996

Hearing loss.

Nearly 30 million Americans have hearing loss. Audiograms are used to determine if hearing loss is sensorineural (SNHL), conductive (CHL), or mixed (MHL). SNHL indicates dysfunction of the cochlea, cochlear nerve, or brain. The study of choice for adults with SNHL is gadolinium-enhanced magnetic resonance imaging, which is used to look for acoustic neuromas, abnormal labyrinth signal intensity or enhancement, and brain disease. In children with SNHL, computed tomography (CT) performed with bone algorithms demonstrates inner ear dysplasias. SNHL from trauma is best evaluated with CT studies. CHL indicates disease in the external auditory canal, tympanic membrane, or middle ear; CT with thin bone algorithms is the best study. Causes of CHL include external canal atresia and neoplasms, myringosclerosis, middle ear anomalies, effusion, cholesteatomas, and neoplasms. MHL is a combination of SNHL and CHL. Dysplasias such as otosclerosis and osteogenesis imperfecta, the most frequent diseases with radiologic findings, are best assessed on CT images. The combination of patient age and type of hearing loss determines the best imaging study.

Adult↗
PubMed1996

Reconstructive myofascial skull-base flaps: normal appearance on CT and MR imaging studies.

On imaging studies, the tendon and fractured coronoid process are clues to the presence of a temporalis myofascial flap. A large, bulky muscle and subcutaneous fat are characteristic of a free flap with microvascular anastomosis. The enhancing, thin, curvilinear pericranial flap bridges an osseous defect of the anterior skull base. Familiarity with these features is essential to avoid misdiagnosis of normal flap as tumor and to identify tumor recurrence.

Humans↗
PubMed1996

T2-weighted MR characteristics of internal auditory canal masses.

PURPOSE: To determine whether masses of the internal auditory canal are hypointense relative to cerebrospinal fluid, and therefore visible, on fast spin-echo T2-weighted MR images. METHODS: Forty-six patients had 50 masses of the internal auditory canal, identified initially on contrast-enhanced MR images, that were evaluated retrospectively for signal intensity of the mass with respect to cerebrospinal fluid and for visibility of the neural elements within the internal auditory canal on T2-weighted images. RESULTS: Forty-seven of 50 masses were clearly identified on T2-weighted images. Three small abnormalities (2 to 4 mm) were not seen with confidence on T2-weighted images. However, on close inspection of these three masses, the small abnormality on contrast-enhanced MR images corresponded to a hypointense focus on T2-weighted images. All 50 masses were hypointense relative to cerebrospinal fluid on T2-weighted images. CONCLUSION: All masses of the internal auditory canal in this study were hypointense relative to cerebrospinal fluid on T-2 weighted images, and were therefore visible.

Cohort Studies↗