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SummarySpontaneous lateral sphenoid cephaloceles arise from bony defects in the lateral sphenoid, in the absence of predisposing factors such as trauma, surgery, mass, or congenital skull base malformation. We reviewed CT and MR imaging findings and clinical data of 26 patients with spontaneous lateral sphenoid cephaloceles to better understand anatomic contributions to pathogenesis, varying clinical and imaging manifestations, and descriptive terminology. Two types of spontaneous lateral sphenoid cephaloceles were identified. In 15 of 26 patients, a type 1 spontaneous lateral sphenoid cephalocele was noted, herniating into a pneumatized lateral recess of the sphenoid sinus, and typically presenting with CSF leak and/or headache. In 11 of 26 patients, a type 2 spontaneous lateral sphenoid cephalocele was noted, isolated to the greater sphenoid wing without extension into the sphenoid sinus, presenting with seizures, headaches, meningitis, cranial neuropathy, or detected incidentally. All patients had sphenoid arachnoid pits, and 61% of patients had an empty or partially empty sella, suggesting that altered CSF dynamics may play a role in their genesis.

Background and purposeThe craniopharyngeal canal is a rare, well-corticated defect through the midline of the sphenoid bone from the sellar floor to the anterosuperior nasopharyngeal roof. We reviewed a series of craniopharyngeal canals to determine a system of classification that might better our understanding of this entity, highlight the range of associated pathologic conditions, and optimize patient treatment.Materials and methodsAvailable MR imaging, CT, and clinical data (from 1989-2013) of 29 patients (10 female, 15 male, 4 unknown; median age, 4 years; age range, 1 day-65 years) with craniopharyngeal canals were retrospectively examined. Qualitative assessment included orthotopic or ectopic adenohypophysis and the presence of a tumor and/or cephalocele. The midpoint anteroposterior diameter was measured. Clinical and imaging data were evaluated for pituitary dysfunction and accompanying anomalies.ResultsCraniopharyngeal canals were qualitatively separated into 3 types: incidental canals (type 1); canals with ectopic adenohypophysis (type 2); and canals containing cephaloceles (type 3A), tumors (type 3B), or both (type 3C), including pituitary adenoma, craniopharyngioma, dermoid, teratoma, and glioma. Quantitative evaluation showed a significant difference (P < .0001) in the anteroposterior diameters of type 1 canals (median, 0.8; range, 0.7-1.1 mm), type 2 canals (median, 3.9, range, 3.5-4.4 mm), and type 3 canals (median, 9.0; range, 5.9-31.0 mm) imparting small, medium, and large descriptors. Canals with cephaloceles all contained an ectopic adenohypophysis. The craniopharyngeal canals were associated with pituitary dysfunction (6/29) and congenital anomalies (8/29).ConclusionsAccurate diagnosis and classification of craniopharyngeal canals are valuable to characterize lesions requiring surgery, identify patients with potential pituitary dysfunction, and avoid iatrogenic hypopituitarism or CSF leak during surgical resection of nasopharyngeal masses.

PURPOSE: 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. METHODS: 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. RESULTS: 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%. CONCLUSION: 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. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the quality of radiographic images digitized from commercial-grade and consumer-grade digital cameras and scanners as viewed on computer monitor. Radiographic images were digitized from hardcopy film using a commercial-grade laser scanner, a consumer-grade desktop flatbed scanner, a commercial-grade digital camera, and a consumer-grade digital camera. The quality of images without and with grayscale histogram adjustment was evaluated subjectively by 10 board-certified radiologists. Optical density response was evaluated objectively using a grayscale test pattern. There was no significant difference in subjective quality among images digitized with the commercial scanner, consumer scanner, and commercial camera. The quality of images digitized with the consumer camera was lower than the other 3. Objective tests showed the commercial scanner to have the most linear optical density response. For the purpose of viewing images on a computer monitor, a consumer-grade desktop scanner can produce images of similar quality to those produced by more expensive laser commercial-grade scanners and digital cameras and provides cost-efficient means to digitize radiographic plain films. A consumer-grade camera may not be optimal for use in this setting. Copyright © 2001 by W.B. Saunders Company [ABSTRACT FROM AUTHOR]

Several studies have addressed the implications of filmless radiologic imaging on telemedicine, diagnostic ability, and electronic teaching files. However, many publishers still require authors to submit hard-copy images for publication of articles and textbooks. This study compares the quality digital images directly exported from picture archive and communications systems (PACS) to images digitized from radiographic film. The authors evaluated the quality of publication-grade glossy photographs produced from digital radiographic images using 3 different methods: (1) film images digitized using a desktop scanner and then printed, (2) digital images obtained directly from PACS then printed, and (3) digital images obtained from PACS and processed to improve sharpness prior to printing. Twenty images were printed using each of the 3 different methods and rated for quality by 7 radiologists. The results were analyzed for statistically significant differences among the image sets. Subjective evaluations of the filmless images found them to be of equal or better quality than the digitized images. Direct electronic transfer of PACS images reduces the number of steps involved in creating publication-quality images as well as providing the means to produce high-quality radiographic images in a digital environment. Copyright © 2001 by W.B. Saunders Company [ABSTRACT FROM AUTHOR]

No publication has discussed utilization of computer scientific exhibits (CSE) at national symposia, despite their growing numbers. The hypothesis of this project was that, when given a choice, viewers initially would prefer a more conventional paper presentation of a scientific exhibit over that of an electronic presentation. A nearly identical paper version of the introductory screen to an infoRAD CSE was placed adjacent to the workstation. Utilization of the paper introduction, computer introduction, and both, as well as subsequent behavior, was recorded. Of 67 visitors, initial user choice was 56.7% paper and 43.3% computer. Over the entire time at the exhibit 25.4% only looked at the handout, 25.4% only at the computer, and 49.3% perused both. Only 10.5% completed the entire exhibit, and 0.94% of total registrants visited the CSE. Overall, 74.7% perused the CSE when leaving the exhibit area. Upon arrival, viewers preferred the more conventional paper presentation, confirming the project hypothesis. Surprisingly, about 75% eventually perused at least a portion of the computer presentation. Although a small fraction of Radiologic Society of North America (RSNA) registrants visited the CSE, the findings presented are promising and suggest that CSE presence at national meetings is justifiable, providing a 'first step' toward CME outcomes analysis of CSE. Overall, these findings are promising and suggest that computer scientific exhibit presence at national meetings is justifiable. Copyright © 2001 by W.B. Saunders Company [ABSTRACT FROM AUTHOR]

PURPOSE: To foster a community supported evaluation processes for open-source digital teaching file (DTF) development and maintenance. The mechanisms used to support this process will include standard web browsers, web servers, forum software, and custom additions to the forum software to potentially enable a mediated voting protocol. The web server will also serve as a focal point for beta and release software distribution, which is the desired end-goal of this process. CONCLUSIONS: We foresee that www.mdtf.org will provide for widespread distribution of open source DTF software that will include function and interface design decisions from community participation on the website forums. Copyright © 2001 by W.B. Saunders Company [ABSTRACT FROM AUTHOR]

Computers are nearly ubiquitous in academic medicine, and authors create and compile much of their work in the electronic environment, yet the process of manuscript submission often fails to utilize the advantages of electronic communication. The purpose of this report is to review the submission policies of major academic journals in the field of radiology and assess current editorial practices relating to electronic submission of academic works. The authors surveyed 16 radiologic journals that are indexed in the Index Medicus and available in our medical center library. They compared the manuscript submission policies of these journals as outlined in recent issues of the journals and the corresponding worldwide web sites. The authors compared the journals on the following criteria: web site access to instructions; electronic submission of text, both with regard to initial submission and final submission of the approved document; text hardcopy requirements; word processing software restrictions; electronic submission of figures, figure hardcopy requirements; figure file format restrictions; and electronic submission media. Although the trend seems to be toward electronic submission, there currently is no clear-cut standard of practice. Because all of the journals that accept electronic documents also require a hardcopy, many of the advantages gained through electronic submission are nullified. In addition, many publishers only utilize electronic documents after a manuscript has been accepted, thus utilizing the benefits of digital information in the printing process but not in the actual submission and peer-review process. Copyright © 2001 by W.B. Saunders Company [ABSTRACT FROM AUTHOR]

The purpose of this report is to compare temporal bone computed tomography (CT) to high-resolution magnetic resonance (MR) imaging using a novel thin-section fast spin echo (FSE) pulse sequence in identifying and characterizing patients with large vestibular aqueduct syndrome. Sixteen patients with sensorineural hearing loss and a CT diagnosis of large vestibular aqueduct(s) underwent high-resolution fast spin echo magnetic resonance imaging with dual, 3-in phased array receiver coils centered over the external auditory canals. Magnetic resonance imaging parameters included axial and oblique sagittal fast spin echo with an effective slice thickness of 1 mm contiguous. Thirty-eight patients with 76 normal inner ears who underwent MR imaging using this technique had their endolymphatic duct measured. MR alone identified the enlarged endolymphatic sac seen along with the large endolymphatic duct in all cases. Three cases (five inner ears) with enlarged bony vestibular aqueducts on CT showed no evidence of endolymphatic duct or sac enlargement on MR. MR alone identified a single case of mild cochlear anomaly in conjunction with an enlarged endolymphatic duct and sac. In the normal population the size of the normal endolymphatic duct at its midpoint measured from 0.1 to 1.4 mm. Thin-section, high-resolution fast spin echo MR imaging of the inner ear may be superior to CT in the evaluation of patients with the large vestibular aqueduct syndrome. [ABSTRACT FROM AUTHOR]

It is challenging to remotely share generic medical case information without an agreed upon definition of a medical digital teaching file (DTF). By utilizing an application of the extensible markup language (XML) called web-distributed data exchange (WDDX) along with an agreed upon WDDX structure, it is technically easy to share or syndicate medical case DTFs across computing environments that use different information models and computer languages. Thus, this easily implemented technology offers us an immediately available means to share and increase the value of scientific knowledge. Copyright © 2001 by W.B. Saunders Company [ABSTRACT FROM AUTHOR]

PURPOSE: The transition from hard-copy film to the picture archiving and communication systems (PACS) arena is often a long and difficult path, but the complete transformation to the digital environment does not end with the successful clinical practice utilizing PACS. The next hurdle for academic institutions is similar changes in the teaching field. The loss of hardcopy films can greatly hinder the radiology teaching file and teaching conference experiences. The next step in our growth is the conversion to digital teaching files and conferences. The original work 10 years ago with utilizing computers linked with laser disks and magneto-optical media, have now evolved into complex networks with expanding and relatively cheap storage media, such as CD-ROM and easily to navigate graphic-user interfaces such as hypertext markup language (HTML) and extensible markup language (XML), for use with multimedia teaching tools. CONCLUSIONS: The transition into the digital arena for radiology education and interdepartmental conferences can be accomplished through several different paths. These include direct transfer of images into a presentation program, as well as exportation of images into suitable image file formats for later use. There is also the ability to expand the PACS network to include conference rooms. Similar training and teaching can allow radiologists to transition into the digital environment for future digital teaching file creation as well as correlative radiology interdepartmental conferences. Copyright © 2001 by W.B. Saunders Company [ABSTRACT FROM AUTHOR]

Background and Purpose: Esthesioneuroblastoma is a neuroectodermal tumor that commonly arises in the nasal cavity olfactory recess and, when isolated to the intranasal cavity, can be indistinguishable from benign processes. Because lesional aggressiveness requires a more invasive operation for resection than polypectomy, patients with isolated intranasal lesions were studied to define distinguishing CT characteristics., Materials and Methods: Patients with intranasal esthesioneuroblastoma and controls without esthesioneuroblastoma with olfactory recess involvement were identified by using a report search tool. Studies demonstrating skull base invasion and/or intracranial extension were excluded. The imaging spectrum of these lesions was reviewed on both CT and MR imaging, and CT findings were compared with those of controls without esthesioneuroblastoma. Two blinded readers assessed subjects with esthesioneuroblastomas and controls without esthesioneuroblastoma and, using only CT criteria, rated their level of suspicion for esthesioneuroblastoma in each case., Results: Eight histologically proved cases of intranasal esthesioneuroblastoma were reviewed. All cases had CT demonstrating 3 main findings: 1) an intranasal polypoid lesion with its epicenter in a unilateral olfactory recess, 2) causing asymmetric olfactory recess widening, and 3) extending to the cribriform plate. Twelve patients with non-esthesioneuroblastoma diseases involving the olfactory recess were used as controls. Using these 3 esthesioneuroblastoma CT criteria, 2 blinded readers evaluating patients with esthesioneuroblastoma and controls had good diagnostic accuracy (area under the curve = 0.85 for reader one, 0.81 for reader 2) for predicting esthesioneuroblastoma., Conclusions: Esthesioneuroblastoma can present as a well-marginated intranasal lesion that unilaterally widens the olfactory recess. CT patterns can help predict esthesioneuroblastoma, potentially preventing multiple operations by instigating the correct initial operative management., (© 2018 by American Journal of Neuroradiology.)

Radiologists have long relied upon the use of metaphoric imaging signs to attribute meaning to disease or anatomy-specific imaging patterns encountered in clinical imaging. Teachers of radiology often employ the use of such signs to help learners rapidly identify the typical appearance of various pathologies. Head and neck (H&N) imaging is no exception, and as a specialty that deals with uncommon pathologies and complex anatomy, learners and practising radiologists alike may benefit from this simplistic, pattern-based approach. In this review, we present a compendium of classic imaging signs of H&N lesions, including signs related to traumatic, infectious, neoplastic, congenital, and inflammatory aetiologies found throughout the spectrum of H&N sites (temporal bones, orbits, paranasal sinuses, larynx, salivary glands, and neck soft tissues). Additionally, we identify potential pitfalls and detail critical clinical ramifications related to the rapid and accurate diagnosis of these pathologies., (Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Background and Purpose: Imaging a cochlear implant with CT is challenging because of implant-induced artifacts, anatomic cochlear variations, and lack of standard terminology for cochlear anatomy. The purposes of this project were to determine whether the cochlear implant tip was more accurately located on oblique CT reformations than on standard images, to review radiology reports for accurate cochlear implant locations, and to assess agreement between an implant surgeon and neuroradiologist by using standardized cochlear anatomy terminology for cochlear implant depth., Materials and Methods: In this retrospective study, a neuroradiologist and an implant surgeon independently viewed temporal bone CT images of 36 ears with cochlear implants. Direct axial images, standard coronal reformations, and oblique reformations parallel to the cochlea were compared to determine implant tip location, which was described by using a proposed standardized quadrant terminology. Implant locations were compared with the initial formal report generated by the original interpreting neuroradiologist., Results: Thirty-six temporal bones with cochlear implants underwent CT interpretation for implant location. Interobserver agreement was similar when comparing cochlear implant tip location by using a quadrant nomenclature on axial and coronal images and on oblique reformations. Clinical radiology reports all were imprecise and ambiguous in describing the location of the cochlear implant tip., Conclusions: Accurate determination of insertion depth of the cochlear implant array can be determined by assessment of the implant tip on axial, coronal, and oblique CT images, but description of the tip location can be inaccurate due to lack of standardized terminology. We propose using a standardized terminology to communicate tip location by using the round window as the zero reference and quadrant numbering to describe cochlear turns. This results in improvement in radiology report accuracy and consistency regarding the cochlear implant insertion depth., (© 2015 by American Journal of Neuroradiology.)

Background and Purpose: While enhanced T1WI is considered the "gold standard" for detection of internal auditory canal pathology, unenhanced fluid-sensitive sequences have shown high sensitivity for lesion identification. Our purpose was to evaluate the diagnostic accuracy of an unenhanced MR imaging protocol using axial CISS and coronal T2WI for detection of small (10 mm or less) internal auditory canal lesions., Materials and Methods: Twenty-three patients with small internal auditory canal lesions and 13 patients without lesions who had undergone MR imaging using the screening protocol and confirmatory gadolinium-enhanced thin section T1WI were identified. Two blinded neuroradiologists retrospectively evaluated all examinations using 1) only axial CISS, 2) only coronal T2WI, and 3) axial and coronal sequences together. Accuracy, specificity, sensitivity, and interobserver agreement were assessed., Results: Median maximum lesion dimension was 4 mm (range, 2-10 mm). Accuracy, specificity, and sensitivity for axial CISS alone were 0.94, 0.96, and 0.91 for observer 1 and 0.94, 0.92, and 1.00 for observer 2. The data for the coronal T2WI sequence only were 0.94, 0.96, and 0.91 for observer 1, and 0.99, 1.00, and 0.96 for observer 2. Using axial and coronal sequences, the data were 0.97, 0.96, and 1.00 for observer 1, and 0.99, 0.98, and 1.00 for observer 2. κ coefficients were 0.84 for the axial sequence only, 0.90 for coronal only, and 0.91 for axial and coronal both., Conclusions: Screening noncontrast MR imaging using a combination of axial CISS and coronal T2WI sequences can detect small internal auditory canal lesions with 100% sensitivity and excellent interobserver agreement., (© 2014 by American Journal of Neuroradiology.)

Summary: Spontaneous lateral sphenoid cephaloceles arise from bony defects in the lateral sphenoid, in the absence of predisposing factors such as trauma, surgery, mass, or congenital skull base malformation. We reviewed CT and MR imaging findings and clinical data of 26 patients with spontaneous lateral sphenoid cephaloceles to better understand anatomic contributions to pathogenesis, varying clinical and imaging manifestations, and descriptive terminology. Two types of spontaneous lateral sphenoid cephaloceles were identified. In 15 of 26 patients, a type 1 spontaneous lateral sphenoid cephalocele was noted, herniating into a pneumatized lateral recess of the sphenoid sinus, and typically presenting with CSF leak and/or headache. In 11 of 26 patients, a type 2 spontaneous lateral sphenoid cephalocele was noted, isolated to the greater sphenoid wing without extension into the sphenoid sinus, presenting with seizures, headaches, meningitis, cranial neuropathy, or detected incidentally. All patients had sphenoid arachnoid pits, and 61% of patients had an empty or partially empty sella, suggesting that altered CSF dynamics may play a role in their genesis.

Background and Purpose: The craniopharyngeal canal is a rare, well-corticated defect through the midline of the sphenoid bone from the sellar floor to the anterosuperior nasopharyngeal roof. We reviewed a series of craniopharyngeal canals to determine a system of classification that might better our understanding of this entity, highlight the range of associated pathologic conditions, and optimize patient treatment., Materials and Methods: Available MR imaging, CT, and clinical data (from 1989-2013) of 29 patients (10 female, 15 male, 4 unknown; median age, 4 years; age range, 1 day-65 years) with craniopharyngeal canals were retrospectively examined. Qualitative assessment included orthotopic or ectopic adenohypophysis and the presence of a tumor and/or cephalocele. The midpoint anteroposterior diameter was measured. Clinical and imaging data were evaluated for pituitary dysfunction and accompanying anomalies., Results: Craniopharyngeal canals were qualitatively separated into 3 types: incidental canals (type 1); canals with ectopic adenohypophysis (type 2); and canals containing cephaloceles (type 3A), tumors (type 3B), or both (type 3C), including pituitary adenoma, craniopharyngioma, dermoid, teratoma, and glioma. Quantitative evaluation showed a significant difference (P < .0001) in the anteroposterior diameters of type 1 canals (median, 0.8; range, 0.7-1.1 mm), type 2 canals (median, 3.9, range, 3.5-4.4 mm), and type 3 canals (median, 9.0; range, 5.9-31.0 mm) imparting small, medium, and large descriptors. Canals with cephaloceles all contained an ectopic adenohypophysis. The craniopharyngeal canals were associated with pituitary dysfunction (6/29) and congenital anomalies (8/29)., Conclusions: Accurate diagnosis and classification of craniopharyngeal canals are valuable to characterize lesions requiring surgery, identify patients with potential pituitary dysfunction, and avoid iatrogenic hypopituitarism or CSF leak during surgical resection of nasopharyngeal masses.

Objective: In the setting of posterior fossa dural venous sinus thrombosis, mastoid findings can potentially be mistaken as the cause rather than a secondary effect. Obstruction of the mastoid venous drainage can lead to transudation of fluid into the mastoid air cells. We hypothesize that a continuum of the mastoid manifestations secondary to dural venous sinus thrombosis can be seen on MRI and that the difference in venous drainage between the mastoid and middle ears can assist with this important imaging differential., Materials and Methods: A retrospective review of acute dural venous sinus thrombosis cases and their follow-up imaging were graded as follows: no involvement; grade 1 mucosal congestion; grade 2, film of fluid; or grade 3, complete opacification. Presence of middle ear fluid was also documented., Results: Of 22 posterior fossa dural venous sinus thrombosis cases without clinical infectious mastoiditis, 19 had mastoid findings: eight with grade 1, eight with grade 2, and three with grade 3. Middle ear fluid was seen in only one case. There was a statistically significant association between posterior fossa dural venous sinus thrombosis and mastoid findings (chisquare test (n = 22), p < 0.04). Fifteen of 18 cases with follow-up MRI examinations showed lessening of the mastoid findings with resolving dural venous sinus thrombosis., Conclusion: Acute posterior fossa dural venous sinus thrombosis may present with a spectrum of mastoid findings that should not be misdiagnosed as the cause of the thrombosis. This study illustrates that in the absence of clinical findings of mastoiditis, mastoid fluid with a clear middle ear argues that the mastoid changes are the effect of the dural venous sinus thrombosis rather than the cause.

Introduction: 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., Methods: 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., Results: 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., Conclusion: 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.

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.

Background and Purpose: ILS is a rare lesion that has a different management from the more common "acoustic" schwannoma. To date, only 137 cases have been reported. We present a classification scheme based on labyrinthine anatomy to describe and localize these lesions. Treatment and prognosis hinge on the appropriate localization of these tumors; thus, a concise terminology that can be used by both the otolaryngologist and radiology communities is desirable., Materials and Methods: After approval of the institutional review board, a retrospective study of all patients with the diagnosis of ILS imaged between 1996 and 2010 was performed. Clinical and imaging data were collected. Patients were imaged with thin-section high-resolution T2 and contrast-enhanced MR imaging., Results: There were 45 patients with a diagnosis of ILS. Forty-three had complete histories. There were 18 male and 25 female patients with an age range of 21-78 years with a mean age of 53 years. The most common presenting symptom was progressive sensorineural hearing loss. Lesions were characterized on the basis of their location. Intracochlear was most common (14/45) followed by transmodiolar (13/45), intravestibular (7/45), vestibulocochlear (5/45), transmacular (4/45), and transotic (2/45). Sixteen patients underwent surgical resection. The remaining patients were followed clinically and by serial MR imaging., Conclusions: ILS is an uncommon but under-reported tumor. We characterized the MR imaging appearance of these tumors by using high-resolution techniques. In addition, an anatomically based classification system is presented that will help the radiologist accurately describe ILS within the inner ear and help the surgeon determine which tumors are potential surgical candidates.

Objective: 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., Materials and Methods: 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., Results: 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., Conclusion: 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.

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.

Parotid gland oncocytoma is an uncommon, benign salivary neoplasm composed of mitochondria-rich oncocytes. The purpose of this study was to correlate MR imaging and histopathology of parotid gland oncocytomas and to define the features that may distinguish these neoplasms from other benign and malignant parotid gland tumors. The MR imaging features in 9 patients with a pathologic diagnosis of oncocytoma were retrospectively reviewed. The imaging features were strikingly similar for 8 of the 9 patients. All lesions appeared T1 hypointense but isointense to the native parotid gland on fat-saturated T2 and postcontrast T1 imaging. On MR imaging, parotid gland oncocytomas share specific imaging characteristics that have not been described for benign or malignant parotid gland tumors. Oncocytomas are isointense to native parotid gland on fat-saturated T2 and T1 postcontrast MR images. Preoperative identification of correct histology may help surgical planning.

Background and Purpose: Advances in multidetector CT provide exquisite detail with improved delineation of the normal anatomic structures in the head and neck. The carotid body is 1 structure that is now routinely depicted with this new imaging technique. An understanding of the size range of the normal carotid body will allow the radiologist to distinguish patients with prominent normal carotid bodies from those who have a small carotid body paraganglioma., Materials and Methods: We performed a retrospective analysis of 180 CTAs to assess the imaging appearance of the normal carotid body in its expected anatomic location., Results: The carotid body was detected in >80% of carotid bifurcations. The normal size range measured from 1.1 to 3.9 mm ± 2 SDs, which is consistent with the reported values from anatomic dissections., Conclusions: An ovoid avidly enhancing structure at the inferomedial aspect of the carotid bifurcation within the above range should be considered a normal carotid body. When the carotid body measures >6 mm, a small carotid body paraganglioma should be suspected and further evaluated.

"Giant" AGs (>1 cm) are uncommon and can be misdiagnosed as venous sinus pathology such as a neoplasm or thrombosis. Seventeen patients with a total of 19 venous sinus AGs of >1 cm were collected from contributing authors. MR imaging was available for all AGs; CT, for 5/19; and DSA, for 7/19. Intra-AG fluid was compared with CSF in subarachnoid spaces. Nonfluid AG tissue was compared with gray matter. Diagnosis was based on imaging findings. Fluid within giant AGs did not follow CSF signal intensity on at least 1 MR image in nearly 80% (15/19) of AGs. Nine of these 15 AGs had CSF-incongruent signal intensity on ≥2 MR images. CSF-incongruent signal intensity was seen in 8/8 AGs on FLAIR, 7/10 on precontrast T1WI, 13/19 on T2WI, and 8/14 on contrast-enhanced T1WI. Nonfluid signal intensity was present in 18/19 AGs and varied from absent/hypointense (intra-AG flow voids) to gray matter isointense (stromal tissue).

Background and Purpose: The larynx is a rare site for primary NHL. Fewer than 100 cases have been reported in the literature, with the largest imaging review involving only 4 patients. We describe the findings of laryngeal lymphoma on CT, PET, and MR imaging and identify features that may distinguish laryngeal lymphoma from the far more common laryngeal squamous cell carcinoma., Materials and Methods: Multi-institutional retrospective chart review revealed 20 patients with histopathologically proved laryngeal lymphoma. Pretreatment CT, PET, and MR images were reviewed by a head and neck radiologist, focusing on extent of tumor, cervical lymph node involvement, and enhancement patterns., Results: Patients ranged from 30 to 90 years of age with a mean of 63 years at the time of initial diagnosis and a 2:1 female predominance. The average tumor size was 37 +/- 19 mm. In all patients, laryngeal lymphoma involved the supraglottis but also extended into the glottis (65%) and hypopharynx (60%). The subglottis was less frequently involved (35%). Laryngeal cartilage invasion and cervical lymphadenopathy were each seen in 20% of patients. Lymphoma was consistently FDG-avid (100%) and usually enhanced uniformly with iodinated contrast (73%). Necrosis and calcification were not seen in any cases., Conclusions: Although laryngeal lymphoma is rare, particular imaging features suggest this diagnosis. A large uniformly enhancing supraglottic tumor without central necrosis and without cervical lymphadenopathy is a characteristic finding of lymphoma. Similar to squamous cell carcinoma, lymphoma may extend into the subglottis, pharynx, and laryngeal cartilages.

Background and Purpose: Chordoma is a relatively rare tumor of the skull base and sacrum thought to originate from embryonic remnants of the notochord. Chordomas arising from the skull base/clivus are typically locally aggressive with lytic bone destruction. When chordomas occur in an extraosseous location, they may mimic other lesions of the nasopharynx. We present 5 cases of primarily extraosseous chordoma involving the nasopharynx in an effort to improve the preoperative diagnosis of this rare tumor. In addition, we review regional notochordal embryology to explain this variant tumor location., Materials and Methods: We reviewed the clinical and imaging data of 5 pathologically proved cases of extraosseous chordoma of the nasopharynx seen or reviewed at our institution during the last decade. All cases had both CT and MR imaging. The study had institutional review board approval., Results: The primary clinical complaint in the 5 patients with extraosseous nasopharyngeal chordoma was nasal obstruction. The extraosseous chordomas were centered in the nasopharynx. Bony lytic changes along the anterior surface of the clivus were seen on 5 of 5 CT studies. A midline sinus tract was seen in 3 of 5 patients. MR imaging showed heterogeneous hyperintense T2 signal intensity (5/5)., Conclusions: Extraosseous nasopharyngeal chordoma is a rare but important lesion to be considered in the differential diagnosis of nasopharyngeal masses. When a midline nasopharyngeal mass is found with an associated clival sinus tract, extraosseous chordoma moves to the top of the differential diagnosis list. Complete removal of the soft-tissue tumor and the clival sinus tract is the treatment of choice in such cases.

We would like to present 6 instances of an internal jugular bulb diverticulum extending into the occipital condyle, which, to the best of our knowledge, has not been described in the English-language literature.This asymptomatic variant was detected incidentally on 6 patients. Computed tomography was performed on all 6 cases, and magnetic resonance imaging and magnetic resonance venography was performed in 2 cases. The condylar jugular diverticula presented as a well-defined defect in the occipital condyle contiguous with the jugular bulb on computed tomography. Magnetic resonance venography showed flow within the diverticulum. There was no definite relationship to a dominant transverse sinus. Recognition of this variant will help to avoid potential confusion with pathological lesions in the occipital condyle, especially on magnetic resonance imaging.

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.

Background and Purpose: The oculomotor cistern (OMC) is a small CSF-filled dural cuff that invaginates into the cavernous sinus, surrounding the third cranial nerve (CNIII). It is used by neurosurgeons to mobilize CNIII during cavernous sinus surgery. In this article, we present the OMC imaging spectrum as delineated on 1.5T and 3T MR images and demonstrate its involvement in cavernous sinus pathology., Materials and Methods: We examined 78 high-resolution screening MR images of the internal auditory canals (IAC) obtained for sensorineural hearing loss. Cistern length and diameter were measured. Fifty randomly selected whole-brain MR images were evaluated to determine how often the OMC can be visualized on routine scans. Three volunteers underwent dedicated noncontrast high-resolution MR imaging for optimal OMC visualization., Results: One or both OMCs were visualized on 75% of IAC screening studies. The right cistern length averaged 4.2 +/- 3.2 mm; the opening diameter (the porus) averaged 2.2 +/- 0.8 mm. The maximal length observed was 13.1 mm. The left cistern length averaged 3.0 +/- 1.7 mm; the porus diameter averaged 2.1 +/-1.0 mm, with a maximal length of 5.9 mm. The OMC was visualized on 64% of routine axial T2-weighted brain scans., Conclusion: The OMC is an important neuroradiologic and surgical landmark, which can be routinely identified on dedicated thin-section high-resolution MR images. It can also be identified on nearly two thirds of standard whole-brain MR images.

Background and Purpose: Imaging characteristics of temporal bone meningioma have not been previously reported in the literature. CT and MR imaging findings in 13 cases of temporal bone meningioma are reviewed to define specific imaging features., Methods: A retrospective review of our institutional case archive revealed 13 cases of histologically confirmed temporal bone meningioma. CT and MR imaging studies were reviewed to characterize mass location, vector of spread, bone changes, enhancement characteristics, and intracranial patterns of involvement. Clinical presenting signs and symptoms were correlated with imaging findings., Results: Thirteen temporal bone meningiomas were reviewed in 8 women and 5 men, aged 18-65 years. Meningiomas were stratified into 3 groups on the basis of location and tumor vector of spread. There were 6 tegmen tympani, 5 jugular foramen (JF), and 2 internal auditory canal (IAC) meningiomas. Tegmen tympani and JF meningiomas were characterized by spread to the middle ear cavity. IAC meningiomas, by contrast, spread to the cochlea and vestibule. Hearing loss was the most common clinical presenting feature in all cases of temporal bone meningioma (10/13). The presence of tumor adjacent to the ossicles strongly correlated with conductive hearing loss (7/9)., Conclusion: Meningioma involving the temporal bone is rare. Three subgroups of meningioma exist in this location: tegmen tympani, JF, and IAC meningioma. Tegmen tympani and JF meningiomas spread to the middle ear cavity. IAC meningiomas spread to intralabyrinthine structures. Conductive hearing loss is commonly seen in these patients and can be surgically correctable.

A persistent cavum septum pellucidum (CSP) is present in approximately 0.73% of adults, although its incidence ranges from 0.14 to 18.9% depending on the detection method. Cystic CSP is even rarer. A cyst causing mass within the CSP can obstruct the intraventricular foramen, leading to blockage of CSF flow and possible hydrocephalus, often justifying surgical intervention. We describe spontaneous decompression of a cystic CSP in a 36-year-old man. Initial MRI showed a cystic CSP with lateral bowing of the septal walls to 1.9 cm. Follow-up MRI 15 months later demonstrated no lateral bowing, and the septal wall width was 1.0 cm. This spontaneous decompression was not explained by the one previously described case report of cystic CSP regression.

Background and Purpose: This paper describes the CT findings that characterize the middle and inner ear anomalies in coloboma, heart defects, choanal atresia, mental retardation, genitourinary, and ear anomalies (CHARGE) syndrome. With this information, neuroradiologists will be better prepared to provide clinically relevant information to their referring physicians regarding this rare syndrome., Materials and Methods: CT studies from 13 patients were reviewed by 2 neuroradiologists with Certificate of Additional Qualification. Each ear was counted separately for a total of 26 ears. Middle and inner ear anomalies associated with CHARGE syndrome were categorized. Investigational review board approval was obtained., Results: Twenty of 26 (77%) ears demonstrated cochlear aperture atresia. Four of these ears were evaluated with MR imaging and were found to lack a cochlear nerve. Twenty-one of 26 (81%) cochlea had some form of dysplasia. Six of 26 (23%) round windows were aplastic. Three of 26 (12%) round windows were hypoplastic. Twenty-one of 26 (81%) oval windows were atretic or aplastic. Fifteen of 26 (58%) vestibules were hypoplastic or dysplastic. There were 5 of 26 (19%) enlarged vestibular aqueducts. Twelve of 26 (46%) vestibular aqueducts had an anomalous course. All cases demonstrated absent semicircular canals. Twenty-three of 26 (88%) facial nerve canals had an anomalous course. Four of 26 (15%) tympanic segments were prolapsed. Three of 26 (12%) temporal bones had an anomalous emissary vein referred to as a petrosquamosal sinus. Twenty-one of 26 (81%) middle ear cavities were small. Twenty-three of 26 (93%) ossicles were dysplastic with ankylosis. Three of 26 (12%) internal auditory canals were small., Conclusion: The CT findings that correlate to the anomalies of CHARGE syndrome affect conductive as well as sensorineural hearing. Stenosis of the aperture for the cochlear nerve aperture on CT is suggestive of hypoplasia or absence of the cochlear nerve, which has been demonstrated in some cases by MR. Absence of the cochlear nerve would be a contraindication to cochlear implantation.

Background and Purpose: Giant cell granuloma (GCG) is a rare lesion. The purpose of this study was to determine the CT characteristics and describe possible MR imaging features of GCG of the craniofacial bones., Methods: We retrospectively reviewed 7 CT studies and 1 MR imaging study of 7 histologically proved cases of GCG in 2 men, 3 women, and 2 patients of unknown gender, aged 12-51 years, during a period of 10 years, from 1995 to 2005., Results: The granulomas predominantly involved the maxilla in 3 patients, the mandible in 2 patients, the temporal bone in 1 patient, and the nasal cavity in 1 patient. These lesions on imaging were expansile masses that demonstrated adjacent bone wall thinning, and most were associated with lytic bone destruction. They were predominantly masses with soft-tissue attenuation on CT scans and may have infiltrated the surrounding soft-tissue structures. The patient with an MR imaging had a lesion that was hypointense on both T1- and T2-weighted MR images. The lesions revealed avid homogeneous contrast enhancement., Conclusion: The imaging features of GCG are nonspecific. However, this entity should be included in the differential diagnosis of expansile lesions in the craniofacial bones.

Background and Purpose: The imaging appearance of facial nerve schwannomas (FNSs) has been described as an enhancing tubular mass (using T1-enhanced MR) within an enlarged facial nerve canal (using CT). The purpose of this study is to identify how often the FNS imaging findings conform to this description and determine whether there are underlying anatomic explanations for the discrepant imaging appearances identified., Materials and Methods: The clinical, pathologic, and radiologic records of 24 FNS in 23 patients were retrospectively reviewed. Each FNS was evaluated for location along the facial nerve. The lesions were cataloged by facial nerve segment with the imaging characteristics of each segment described., Results: The average age at time of first imaging was 39 years (age range, 10-70 years). Eighteen (71%) of the 24 FNSs were pathologically confirmed, while the others were determined intraoperatively or diagnostically by the presence of both enlargement of the facial nerve canal and enhancement on contrast-enhanced T1 MR examination. The most common location was in the geniculate fossa (83%), followed by the labyrinthine and tympanic segments of the facial nerve (both 54%). The most common clinical presentation was facial neuropathy (42%)., Conclusion: The classic description of FNS on enhanced T1 MR is that of a well-circumscribed fusiform enhancing mass along the course of the intratemporal facial nerve with bone algorithm CT showing sharply defined bony canal enlargement. Modern imaging techniques, however, demonstrate the importance of the surrounding anatomic landscape, leading to various imaging appearances. Lesions traversing the labyrinthine segment can demonstrate a dumbbell appearance. When FNSs track along the greater superficial petrosal nerve, they may present as a round mass projecting up into the middle cranial fossa. FNS of the tympanic segment of the facial nerve preferentially pedunculate into the middle ear cavity, clinically presenting as a middle ear mass. When the mastoid segment of the facial nerve is involved, irregular and "invasive" tumor margins seen on MR can be explained on CT as tumor breaking into surrounding mastoid air cells.

Objective: To outline the diagnosis and management of intralabyrinthine schwannomas and to propose a new classification system to further define them., Study Design: Retrospective case review., Setting: Tertiary referral center at a university hospital., Patients: Twenty-eight patients seen at the institution with intralabyrinthine schwannomas between 1996 and 2002 were included in the study., Interventions: 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., Main Outcome Measures: Clinical features, audiology, radiology, and management outcomes were evaluated., Results: 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., Conclusion: 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.

Objective: 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., Materials and Methods: 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., Results: 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., Conclusion: 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.

Objectives: 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., Study Design: We present a series of six consecutive large jugular foramen meningiomas resected by a single surgeon from 1996 to 2002., Methods: Retrospective case series (chart review)., Results: 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., Conclusions: 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.

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.

Background and Purpose: 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., Methods: 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., Results: 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., Conclusion: 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.

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.