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ABSTRACT: This study aimed to describe the lateralized petrous internal carotid artery (ICA), a rare variant of the intratemporal course of the ICA, and distinguish it from aberrant ICA.
A retrospective multi-institutional review of all patients diagnosed over a 10-year period with lateralized ICA was completed. Medical records were reviewed for demographic data as well as clinical information in all patients. Computerized tomography (CT) studies were reviewed in all patients. Magnetic resonance studies in this patient group were reviewed when available. In order to obtain normative data for the ICA, the intratemporal course of the ICA was evaluated on 50 consecutive high-resolution sinus CT scans.
Sixteen cases of lateralized ICA were identified on CT scans in 12 patients. In each of these, the ICA entered the skull base in a position more lateral to the cochlea than normal and protruded into the anterior mesotympanum with dehiscent or thinned overlying bone. Magnetic resonance angiography was available in 5 of 12 patients and catheter angiography in 1 of 12.
Lateralized petrous ICA can be identified on CT by its more posterolateral entrance to the skull base and protrusion into the anterior mesotympanum. It can be distinguished from the aberrant ICA which enters the posterior hypotympanum through an enlarged inferior tympanic canaliculus, then courses across the inferior cochlear promontory to connect with the normal horizontal petrous ICA. Lateralized ICA is best considered an incidental petrous ICA variant. Awareness of this entity is important in the presurgical evaluation of the temporal bone to avoid vascular injury and confusion with the congenital diagnosis of aberrant ICA.
Neuroradiology 04/2012; 54(9):1007-13. · 2.82 Impact Factor
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ABSTRACT: Lymphoceles are benign neck cysts that are important to differentiate from congenital, infectious, and malignant cystic neck masses because they require unique surgical treatment and follow-up. We reviewed a series of surgically proven lymphoceles to delineate the radiologic characteristics of lymphoceles that differentiate them from other cystic neck masses.
A search of radiology report impressions for the terms "lymphocele" and "lymphatic cyst" was performed on all neck CT, MRI, and sclerotherapy studies from January 2003 to December 2009 at our institution. Clinical and pathology records were searched for the same terms to identify additional cases. Medical records confirmed diagnosis. Study images were reviewed on PACS to assess cyst location and imaging characteristics.
There were nine patients (six women and three men; age range, 22-85 years; mean age, 50.1 years) with 12 pathologically proven lymphoceles on six contrast-enhanced CT and three contrast-enhanced MRI examinations. Lymphoceles were located in the posterior cervical space in 12 of 12 and supraclavicular in 10 of 12 cases. Lymphoceles were unilocular nonseptated cysts in 12 of 12, fluid density or signal in 11 of 12, nonenhancing in 12 of 12, and lacked a cyst wall in eight of 12.
Lymphoceles are rare unilocular cystic neck masses that may mimic other congenital, infectious, and malignant neck cysts. When enhanced CT or MRI shows a unilocular, nonseptated, fluid density or intensity, and nonenhancing supraclavicular cyst in the posterior cervical space, lymphocele is an important part of the differential diagnosis. Atypical features warrant fine-needle aspiration or follow-up for confirmation.
American Journal of Roentgenology 12/2011; 197(6):1431-5. · 2.78 Impact Factor
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ABSTRACT: Ganglion cysts arising from the temporomandibular joint are rare entities that often present with swelling and minimal to no pain in the preauricular region. To the authors' knowledge, a temporomandibular joint ganglion cyst occurring with acute facial nerve palsy and intracranial extension has never been reported. The patient in the current case initially underwent treatment for Bell palsy and then draining of the cyst at an outside hospital with no relief of symptoms. Repeat MR imaging showed an increase in the size of the cystic, enhancing, middle fossa lesion measuring 4 cm. Resection of the lesion was undertaken using a middle fossa approach. After a satisfactory surgical decompression, the patient demonstrated a significant recovery in her facial palsy over a 3-month period of time. This case presents new clinical and radiographic findings associated with these lesions.
Journal of Neurosurgery 11/2011; 116(2):310-2. · 2.96 Impact Factor
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ABSTRACT: In the assessment of the head and neck, differential diagnoses can be formulated by subdividing the anatomy into spaces along identifiable and logical boundaries. In the oral cavity, the root of the tongue is notably unlike adjacent regions due to structural and tissue-specific differences. The majority of lesions found in the root of the tongue are congenital and benign, representing ectopic tissues of thyroidal, epidermal, dermal, foregut, venous, and lymphatic origin. A greater number of acquired neoplasms and infections are seen in the adjacent sublingual, submandibular, and oropharyngeal regions of the base of the tongue, presumably due to their greater exposure to mucosal surfaces and lymphatic tissues. Many lesions of the root of the tongue have clinical and imaging characteristics that can help narrow the differential diagnosis, and surgical management may be required. Familiarity with these lesions and how they differ from other lesions of the oral cavity and oropharynx can significantly aid in their diagnosis and treatment.
Radiographics 11/2011; 31(7):1907-22. · 2.85 Impact Factor
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ABSTRACT: Decision support systems for radiologists can provide information during image interpretation that may efficiently improve diagnostic accuracy and increase radiologists' confidence. However, most decision support systems require radiologists to exit PACS, which may deter busy radiologists from pursuing decision support. The purpose of this study was to determine whether radiologists would use a PACS-integrated decision support tool more frequently than an equivalent nonintegrated system.
Forty-eight radiology residents were randomly assigned to one of two groups: the control group was provided access to a radiology clinical decision support tool via Web access, which required the resident to launch a Web browser from a desktop icon and then log in to the decision support application. The experimental group was provided access to the same tool but was allowed to launch from a PACS-integrated portal with automated login and authentication. Halfway through the 10-month study period, the groups were switched. The main outcome measure was the average number of decision support sessions initiated each month over the study period.
The experimental (integrated) group had higher use than the control (nonintegrated) group by a factor of 3.0 (P < .05). When integrated access was removed from the experimental group, their use fell by 52%. When integrated access was granted to the control group, their use rose by only 20%.
Integration with PACS improves radiologists' use of clinical decision support tools. Integrated access is critical at the time of initial deployment, or acceptance of the decision support tools may be undermined.
Journal of the American College of Radiology: JACR 07/2011; 8(7):497-500.
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ABSTRACT: To describe the imaging findings and clinical outcomes of children with apparent cochlear nerve aplasia undergoing cochlear implantation.
Retrospective case review.
Tertiary care center.
Three patients with imaging findings consistent with absent cochlear nerve canal on diagnostic imaging and questionable audiometric responses on testing who underwent promontory stimulation and subsequent cochlear implantation.
Magnetic resonance imaging and computed tomography, audiologic assessment, and cochlear implantation.
Audiologic performance after cochlear implantation.
Three patients were identified to have hearing loss on newborn hearing screening and underwent auditory brainstem response testing revealing absent brainstem responses. ASSR testing was inconclusive when performed. Imaging in all cases identified 1 ear with a small internal auditory canal with 2 nerves present, one of which seems to enter the vestibule in each case and the other is assumed to be the functioning facial nerve. There was a bony plate present over the entrance to the cochlea in 2 of the 3 patients. Over time, 2 of the families reported responses to auditory stimuli with amplification. Promontory stimulation testing showed reproducible responses to electrical stimuli in the ears in question. After cochlear implantation, all 3 patients have shown responses to auditory stimuli.
The absence of a visible cochlear nerve or cochlear nerve canal on radiologic imaging does not preclude auditory innervation of the cochlea. Cochlear implantation can be a viable option for patients with apparent cochlear nerve aplasia who have undergone appropriate testing. Electronically evoked auditory brainstem response is critical in the evaluation of this patient group.
Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 09/2010; 31(7):1088-94. · 1.44 Impact Factor
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ABSTRACT: OBJECTIVE: We present the largest case series in the English-language imaging literature, emphasizing the variety of presentations of Rosai-Dorfman disease in the head and neck. CONCLUSION: Rosai-Dorfman disease is a rare disorder with multiple sites of involvement in the head and neck.
American Journal of Roentgenology 01/2009; 191(6):W299-306. · 2.78 Impact Factor
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ABSTRACT: To describe characteristic features of metastatic lesion to the cerebellopontine angle (CPA) and internal auditory canal (IAC).
Retrospective review.
Tertiary care medical center.
Patients with metastatic lesions to the CPA.
Diagnostic.
Clinical presentation and imaging characteristics on magnetic resonance imaging and computed tomography.
A total of 25 cases were reviewed. The average patient age was 56 years, and almost all patients presented with palsy of the cranial VII and VIII nerves. There were 14 cases of metastases to the CPA, 16 cases to the IAC, 5 cases to the CPA and IAC, and 7 cases to the dura. There were several identifiable patterns of metastases to the CPA/IAC, including the flocculus (5), pia/arachnoid (12), dura (7), and choroid plexus (3). T1 magnetic resonance imaging was most commonly isointense to hypointense to brain, with enhancement on T1 imaging with contrast. Lesions tend to be eccentric to the IAC. T2 and fluid-attenuated inversion-recovery (FLAIR) imaging shows adjacent cerebellar and brainstem vasogenic edema. Characteristics that differentiate metastatic lesions from benign lesions of the CPA include vasogenic edema on T2 and FLAIR imaging and multiple central nervous system lesions and lesions that are eccentric to the IAC.
Recognizing characteristic patterns of spread to the CPA and IAC can aid the clinician in the diagnosis of metastatic lesions to this area. Clinical history of rapidly progressive cranial nerve deficits, particularly facial paralysis in a patient with a history of malignancy, increases the level of suspicion. Imaging characteristics of metastatic lesions to the CPA include adjacent vasogenic edema observed on T2-weighted imaging and FLAIR, eccentric location to the IAC, and multiple lesions observed on head and neck imaging.
Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 09/2008; 29(6):835-8. · 1.44 Impact Factor
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ABSTRACT: Congenital mastoid cholesteatomas are rare lesions of the temporal bone. The clinical presentation of these lesions is variable, making them difficult to identify preoperatively. We evaluated our series of mastoid congenital cholesteatomas (CCs) in an effort to better define the clinical presentation, imaging characteristics, and surgical challenges specific to this lesion.
Retrospective chart and radiologic study review.
The medical records of patients with the diagnosis of mastoid CC on radiologic imaging over a 15-year period were reviewed. All had surgical and pathologic confirmation. Eight patients underwent preoperative computed tomography (CT). Six also underwent magnetic resonance (MR) scanning. Demographic information, clinical presentation, imaging results, and operative findings were recorded.
Nine patients with the diagnosis of mastoid CC satisfying the inclusion criteria were found. Clinical findings were variable, with the most common presentation being an incidental finding. Imaging findings were more uniform. All CT scans demonstrated an expansile, well-circumscribed mass centered within the mastoid portion of the temporal bone. All MR scans showed a well-circumscribed mass with high intensity on T2-weighted images with precontrasted T1 sequences showing the lesion to be isointense or slightly hyperintense to cerebrospinal fluid (CSF). Operative findings included lateral mastoid cortex erosion, sigmoid sinus exposure, ossicular destruction, facial nerve exposure, and associated postauricular abscess. Management of these lesions is reviewed.
Congenital mastoid cholesteatomas have a variable and nonspecific clinical presentation. Surgical challenges arise from the indolent nature of this clinical entity, which belies the extent of otologic involvement. Imaging with CT and magnetic resonance imaging are diagnostic, defines the extent of these lesions, and facilitates preoperative surgical planning.
The Laryngoscope 09/2007; 117(8):1389-94. · 1.75 Impact Factor
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ABSTRACT: To outline the diagnosis and management of intralabyrinthine schwannomas and to propose a new classification system to further define them.
Retrospective case review.
Tertiary referral center at a university hospital.
Twenty-eight patients seen at the institution with intralabyrinthine schwannomas between 1996 and 2002 were included in the study.
Diagnosis was made with magnetic resonance imaging in all but one case. Our ability to detect these tumors has been greatly enhanced by the introduction of high-resolution T2-weighted magnetic resonance imaging. Treatment options were observation with serial magnetic resonance imaging versus complete surgical removal via a translabyrinthine or transotic approach. Surgery was indicated for dizziness caused by the tumor or extralabyrinthine growth.
Clinical features, audiology, radiology, and management outcomes were evaluated.
Eight patients have undergone successful surgery with removal of their tumors and resolution of symptoms. One patient chose to have stereotactic radiotherapy. Of the 20 patients who were managed with observation and serial magnetic resonance imaging, only 1 has shown significant growth requiring surgical removal.
Intralabyrinthine schwannomas are uncommon tumors that mimic the clinical features of many other neurotologic conditions. A high index of suspicion and precise imaging are often required to detect these tumors. Surgical treatment is indicated for specific indications and will be needed in the minority of patients with this disorder. The classification system that we propose is helpful in both the diagnosis and the management of these tumors.
Ontology & Neurotology 04/2004; 25(2):160-7. · 1.90 Impact Factor
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ABSTRACT: Primary jugular foramen meningiomas behave differently from meningiomas arising elsewhere. The differences have important clinical, imaging, and surgical implications. We reviewed the imaging appearances of primary jugular foramen meningiomas and evaluated them for features that might assist in differentiating them from other common jugular foramen lesions.
A retrospective review identified five cases of primary jugular foramen meningioma. We defined it as primary when it was centered in the jugular foramen and secondary when it was centered in the posterior fossa with secondary extension into the jugular foramen. Secondary jugular foramen meningiomas were excluded from this study. Eight cases of jugular foramen paraganglioma and 10 cases of jugular foramen schwannoma were reviewed for comparison.
Primary meningioma was characterized by centrifugal infiltration surrounding the skull base (5/5), a permeative-sclerotic appearance to the bone margins of the jugular foramen (5/5), and prominent dural tails (5/5). Flow voids were absent in all cases. Paraganglioma showed localized skull base infiltration, with predominant superolateral spread into the middle ear cavity (8/8). Flow voids and permeative destruction of the bone margins of the jugular foramen were typical. Schwannoma caused expansion of the jugular foramen with scalloped well-corticate bone margins, without skull base infiltration.
Primary jugular foramen meningioma is characterized by extensive skull base infiltration. A centrifugal pattern of spread, a permeative-sclerotic appearance of the bone margins of the jugular foramen, the presence of dural tails, and an absence of flow voids are particularly important features that assist in differentiating primary jugular foramen meningioma other more common jugular foramen lesions.
American Journal of Roentgenology 03/2004; 182(2):373-7. · 2.78 Impact Factor
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ABSTRACT: Meningiomas involving the jugular foramen are rare lesions, with approximately 34 cases reported in the English literature. Clinically, these tumors mimic the more common glomus jugulare tumor. After surgical resection, meningiomas have worse cranial nerve outcomes and higher recurrence rates than glomus tumors. There is controversy regarding the selection of surgical approach, particularly with regard to management of the facial nerve. A reliable means of accurate preoperative diagnosis would help surgical planning and patient counseling.
We present a series of six consecutive large jugular foramen meningiomas resected by a single surgeon from 1996 to 2002.
Retrospective case series (chart review).
The preoperative diagnosis was correct in nearly all (6/7) cases on the basis of the characteristic imaging findings seen with a combination of temporal bone dedicated computed tomography and high-resolution enhanced magnetic resonance imaging. Five of six patients had lateral facial nerve rerouting (infratemporal fossa Fisch type A), and three patients also had posterior rerouting (transcochlear approach with division of greater superficial petrosal nerve). Total tumor removal was accomplished in 83%. One patient suffered recurrence over a mean follow-up period of 2.5 years. New postoperative vocal cord palsies occurred in 50% of patients, and all required vocal cord medialization. At 1 year, 50% of patients had normal or near normal (House-Brackmann I or II) facial function. Postoperative cerebrospinal fluid leaks occurred in two patients, and both eventually required ventriculoperitoneal shunts.
Meningiomas involving the jugular foramen are surgically challenging tumors that pose unique diagnostic issues. The majority of these lesions can be completely resected. A relatively high postoperative complication rate, which can be controlled with appropriate intervention, is seen with these surgeries.
The Laryngoscope 02/2004; 114(1):25-32. · 1.75 Impact Factor
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ABSTRACT: Primary intraosseous cavernous hemangiomas (PICHs) of the skull base are extremely rare tumors. These lesions are most common in the frontal and parietal bones of the calvarium. The authors describe a 40-year-old female who presented with progressive headaches. Serial imaging revealed a contrast-enhancing intraosseous lesion of the lateral body of the sphenoid bone and the greater wing associated with encroachment of the inferior cavernous sinus and mild posterior displacement of the cavernous carotid artery. Follow-up imaging 9 years later revealed slow growth of the lesion. The patient underwent complete excision of the PICH through an extradural frontopolar approach. Pathological examination revealed an intraosseous cavernous hemangioma. PICHs of the skull base can mimic other more common skull base lesions and thus can be difficult to diagnose preoperatively. Diagnosis is usually made at surgery. The authors review the literature regarding the clinical presentation, radiological characteristics, pathological features, and surgical management of PICHs.
Skull Base 12/2003; 13(4):219-228. · 0.66 Impact Factor
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ABSTRACT: Masses in the parotid tail can be a source of consternation to radiologists and clinicians; inaccurate localization may lead to significant iatrogenic complication. We sought to review the pertinent anatomic localizing features of the parotid tail, relevant facial nerve anatomy, and sources of clinical and radiologic confusion. To conclude, we review imaging features that are helpful in generating a diagnosis in this location.
We retrospectively reviewed the imaging and clinical features of 111 parotid tail masses in 103 patients (56 male, 45 female, two of unknown sex; age range, 5 months-81 years). The following imaging findings were noted: size, enhancement, multiplicity of lesions, attenuation on CT scans, signal intensity on MR images, and appearance of the surrounding parotid gland. Diagnosis was confirmed by either surgical resection or biopsy findings or by specific clinical data or characteristic imaging findings.
Seventeen types of parotid tail masses were identified. Benign lesions were: pleomorphic adenoma (n = 15), Warthin tumor (n = 14), infectious process (n = 13), venous malformation (n = 9), and Sjögren disease (n = 9), lymphatic malformations (n = 7), lipoma (n = 6), HIV lymphoepithelial lesion (n = 4), first brachial cleft cyst (n = 3), oncocytoma (n = 2), sarcoid (n = 1), and lymph node (n = 1). Malignant lesions were: Non-Hodgkin lymphoma (n = 14), metastatic disease (n = 7), mucoepidermoid carcinoma (n = 4), acinic cell carcinoma (n = 1), and undifferentiated carcinoma (n = 1). Eight patients had two diagnoses.
Understanding normal parotid tail anatomy is important to radiologists, because accurate localization has implications for appropriate management of masses in this location, potentially reducing the occurrence of marginal mandibular nerve injury.
American Journal of Neuroradiology 11/2003; 24(9):1757-64. · 2.93 Impact Factor
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ABSTRACT: Anomalies of the course of the facial nerve have been reported in association with middle and inner ear malformations. Bifurcation of its intratemporal portion is a rare malformation in which focal splitting of one or more facial nerve segments occurs. We describe the CT appearance of this anomaly and discuss its possible embryology. Facial nerve bifurcation is important to recognize in patients undergoing evaluation for congenital hearing loss and other congenital ear malformations.
American Journal of Neuroradiology 09/2003; 24(7):1334-7. · 2.93 Impact Factor
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ABSTRACT: Cholesteatoma is an inflammatory lesion of the temporal bone that uncommonly involves the external auditory canal (EAC). In this large case series, we aimed to define its imaging features and to determine the characteristics most important to its clinical management.
Thirteen cases of EAC cholesteatoma (EACC) were retrospectively reviewed. Clinical data were reviewed for the history, presentation, and physical examination findings. High-resolution temporal bone CT scans were examined for a soft-tissue mass in the EAC, erosion of adjacent bone, and bone fragments in the mass. The middle ear cavity, mastoid, facial nerve canal, and tegmen tympani were evaluated for involvement.
Patients presented with otorrhea, otalgia, or hearing loss. Eight cases were spontaneous, and five were postsurgical or post-traumatic. CT imaging in all 13 cases showed a soft-tissue mass with adjacent bone erosion. Intramural bone fragments were identified in seven cases. This mass most often arose inferiorly (n = 8) or posteriorly (n = 8), but it was circumferential in two cases. We noted middle ear extension (n = 5), mastoid involvement (n = 4), facial canal erosion (n = 2), and tegmen tympani dehiscence (n = 1).
Temporal bone CT shows EACC as a soft-tissue mass within the EAC, with adjacent bone erosion. Bone fragments may be present within the mass. The cholesteatoma may extend into the mastoid or middle ear, or it may involve the facial nerve canal or tegmen tympani. Recognition of this entity and its possible extension is important because it may influence clinical management.
American Journal of Neuroradiology 05/2003; 24(4):751-6. · 2.93 Impact Factor
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ABSTRACT: Occasionally, diving ranulas may attain large dimensions (giant ranula); gross involvement of the submandibular and parapharyngeal spaces makes differentiation from other cystic neck masses, particularly cystic hygroma, difficult. As diving ranula and cystic hygroma are managed with different surgical approaches, avoidance of this pitfall is critical. Our purpose was to review the imaging findings of giant ranula and compare them with those of cystic hygroma to define those features that are helpful in differentiating these different disease entities.
We conducted a retrospective review of all cases of ranulas that had been surgically treated at our institution in a 15-year period. These were compared with cases of cystic hygroma that involved the same anatomic regions. Images were analyzed for anatomic location and morphology, with specific attention paid to those characteristics that might assist differentiation. Giant ranula was defined as any ranula that significantly involved the paraphyngeal space in addition to the submandibular space.
Six patients with giant ranula and fifteen patients with cystic hygroma were reviewed. All giant ranulas retained tapered communication with the sublingual space and were homogeneous, thin-walled, anatomically defined, fluid-containing masses. One infected lesion enhanced, and another previously operated lesion demonstrated mild septation. Cystic hygroma commonly did not communicate with the sublingual space and had features of lobulation, septation and heterogeneity. Additional involvement of spaces not typically involved by ranula further assisted differentiation.
Although giant ranulas may superficially resemble cystic hygroma, several imaging features allow confident differentiation of these two entities.
American Journal of Neuroradiology 05/2003; 24(4):757-61. · 2.93 Impact Factor
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ABSTRACT: A 5-year-old boy was evaluated for a left retrotympanic mass found at otoscopy. Subsequent petrous bone CT and MR angiographic examinations demonstrated bilateral aberrant internal carotid, bilateral stapedial artery persistence, and bilateral duplicated internal carotid arteries. Imaging findings and their clinical relevance are discussed. A second case of unilateral aberrant internal carotid artery with a persistent stapedial artery is included for comparison.
American Journal of Neuroradiology 05/2003; 24(4):762-5. · 2.93 Impact Factor
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ABSTRACT: Intracranial lipomas are uncommon congenital malformations that most often are asymptomatic. A rare subset of intracranial lipomas arises within the vestibule of the inner ear, which can cause sensorineural hearing loss. We present the CT and MR imaging characteristics of lipomas within the vestibule of the inner ear and propose a pathogenetic mechanism for this malformation.
We retrospectively reviewed five cases of vestibular lipoma. T1-weighted axial conventional spin-echo and T2-weighted axial fast spin-echo sequences were performed in all five cases. Four patients underwent T1-weighted fat-saturated imaging, and one underwent CT scanning with Hounsfield units measured.
Four female patients ranging in age from 10 to 40 years and one 26-year-old male patient had sensorineural hearing loss. Two patients had progressive high-frequency loss; one, sudden-onset high-frequency loss; and two, congenital high-frequency loss. All had lesions within the vestibule that displayed hyperintensity on T1-weighted images, isointensity to slight hypointensity on T2-weighted fast spin-echo images, hypointensity with fat saturation, and fat attenuation on CT scans. Three of the cases were associated with lipoma of the cerebellopontine angle. In none of these cases were the cerebellopontine angle and labyrinthine lipomas contiguous.
Intravestibular lipoma is considered when a focal hyperintense lesion is identified within the vestibule of the inner ear on T1-weighted MR images. Lesion hypointensity on fat-saturated T1-weighted MR images verifies its lipomatous nature and separates it from intralabyrinthine hemorrhage or highly proteinaceous fluid.
American Journal of Neuroradiology 10/2002; 23(8):1413-7. · 2.93 Impact Factor
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ABSTRACT: High-resolution T2-weighted fast spin-echo MR imaging provides excellent depiction of the cisternal and intracanalicular segments of the vestibulocochlear and facial nerves. Absence or reduction in caliber of the cochlear nerve (deficiency) has been described in association with congenital sensorineural hearing loss (SNHL). Depiction of cochlear nerve integrity may be important for diagnosis and management of SNHL.
We retrospectively reviewed high-resolution T2-weighted fast spin-echo MR images of 22 patients examined for SNHL who had deficiency of the cochlear nerve. Images were evaluated for the presence and comparative size of the component nerves (facial, cochlear, superior vestibular, and inferior vestibular nerves), relative size of the internal auditory canal (IAC), and any associated inner ear abnormalities. The clinical history, results of the clinical examination, and audiometric findings were reviewed for each patient.
Deficiency of the cochlear nerve was observed in 12 patients with congenital SNHL and in 10 patients with acquired SNHL. Hypoplasia of the IAC was observed in association with congenital deficiency of the cochlear nerve in 11 of 12 patients. Deficiency of the cochlear nerve was observed in association with acoustic schwannoma in two cases and with acquired labyrinthine abnormalities in seven cases. Hypoplasia of the IAC was not observed in association with acquired SNHL.
Deficiency of the cochlear nerve can be shown by high-resolution T2-weighted fast spin-echo MR imaging. Deficiency may be observed in association with congenital or acquired SNHL and may be important in the assessment of patients for cochlear implantation. Hypoplasia of the IAC is an indicator of congenital cochlear nerve deficiency.
American Journal of Neuroradiology 05/2002; 23(4):635-43. · 2.93 Impact Factor
