Biomedical subjects

R H Wiggins

Publications and source records attributed to R H Wiggins.

12 recordsLinked to original sources

PubMed2006

The many faces of facial nerve schwannoma.

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.

Adolescent↗

PubMed2006

CT and MR imaging of giant cell granuloma of the craniofacial bones.

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.

Adolescent↗

PubMed2006

Absent semicircular canals in CHARGE syndrome: radiologic spectrum of findings.

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.

Abnormalities, Multiple↗

PubMed2001

Distance learning in the digital environment.

The expansion of radiology departments and divisions often can not occur in adjacent geographic locations. This leads to a greater separation of staff and residents, as well as workers in similar divisions. This makes traditional teaching difficult in academic institutions. The economic drive forcing many departments to investigate more isolated outpatient imaging centers has further hindered the ability to continue effective academic training at many facilities. The ability to easily share a digital environment across physical distance can greatly enhance the teaching experience, as well as be a valuable tool for consultation and case discussion with referring clinicians. The transition to a filmless environment with picture archiving and communication systems (PACS) can be utilized for distance learning in addition to the clinical arena. It is possible to take advantage of the digital transformation to PACS and case-viewing browser programs to conduct improved interactions with referring clinicians as well as radiologic teaching with relatively minimal hardware and software demands. The integration of web-based teleradiology programs with business networking software can be used for effective distance learning in the digital environment, sufficiently closing the distance on our rapidly expanding departments. This same technology allows for greater interaction with referring clinicians for real-time consultation and enhanced case discussion to entrench a supportive referral base for the radiologic community.

Humans↗

PubMed2001

The evolution of filmless radiology teaching.

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.

Computer-Assisted Instruction↗

PubMed2001

Electronic submission of academic works: a survey of current editorial practices of radiologic journals.

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.

Humans↗

PubMed2001

Digital processing of radiographic images from PACS to publishing.

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.

Analysis of Variance↗

PubMed2001

Computerized scientific exhibit utilization: observations from infoRAD at the radiologic society of North America Scientific Assembly.

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.

Audiovisual Aids↗

PubMed2001

Intratemporal facial nerve neuroma: anatomical location and radiological features.

OBJECTIVES: To present the imaging findings and anatomical locations of a series of 88 facial nerve neuromas from two centers over a 30-year period. We describe the salient radiological features of neuromas in each anatomical location and outline the ways in which modern imaging techniques have altered our perception of this entity. STUDY DESIGN: A retrospective review of tumors presenting to two tertiary care referral institutions since 1970. METHODS: The charts and available imaging of patients with the diagnosis of facial neuroma were reviewed. These patients presented to the House Ear Clinic between 1970 and 1994 and to the University of Utah Medical Center (Salt Lake City, UT) between 1986 and August 2000. We examined anatomical location to determine patterns of tumor presentation and compared the findings before and after the era of magnetic resonance imaging (MRI). RESULTS: All segments of the facial nerve were represented. Overall, multiple-segment tumors were almost twice as common (63.6%) as single-segment tumors (36.4%). Before the advent of MRI, all segments of the nerve from the cerebellopontine angle to the tympanic portion were almost equally represented (29.5%-36.3%). After MRI, the geniculate ganglion (68.2%) and labyrinthine portion (52.3%) were by far the most commonly affected areas. Before MRI, there were, on average, 1.89 segments involved per tumor. After MRI, this average number increased to 2.57 segments per tumor. Radiologically, the high-resolution computed tomography and MRI features cannot be generalized. Rather, the imaging features depend on which segments are involved. This is because of the variation in the surrounding anatomical landscape of the facial nerve in its course through the temporal bone. CONCLUSION: The more sensitive imaging provided by newer radiological techniques has altered our perception of facial neuroma. It has provided us with an increased ability to diagnose and fully evaluate this neoplasm preoperatively, allowing improved patient counseling and surgical planning.

Adolescent↗

PubMed2001

Dumbbell schwannomas of the internal auditory canal.

BACKGROUND AND PURPOSE: Benign tumors of the internal auditory canal (IAC) may leave the confines of the IAC fundus and extend into inner ear structures, forming a dumbbell-shaped lesion. It is important to differentiate dumbbell lesions, which include facial and vestibulocochlear schwannomas, from simple intracanalicular schwannomas, as surgical techniques and prognostic implications are affected. In this article, the imaging and clinical features of these dumbbell schwannomas are described. METHODS: A dumbbell lesion of the IAC is defined as a mass with two bulbous segments, one in the IAC fundus and the other in the membranous labyrinth of the inner ear or the geniculate ganglion of the facial nerve canal, spanned by an isthmus. Twenty-four patients with dumbbell lesions of the IAC had their clinical and imaging data retrospectively reviewed. Images were evaluated for contour of the mass and extension into the membranous labyrinth or geniculate ganglion. RESULTS: Ten of 24 lesions were facial nerve dumbbell lesions. Characteristic features included an enhancing "tail" along the labyrinthine segment of the facial nerve and enlargement of the facial nerve canal. Dumbbell schwannomas of the vestibulocochlear nerve (14/24) included transmodiolar (8/14), which extended into the cochlea, transmacular (2/14), which extended into the vestibule, and combined transmodiolar/transmacular (4/14) types. CONCLUSION: Simple intracanalicular schwannomas can be differentiated from transmodiolar, transmacular, and facial nerve schwannomas with postcontrast and high-resolution fast spin-echo T2-weighted MR imaging. Temporal bone CT is reserved for presurgical planning in the dumbbell facial nerve schwannoma group.

Adolescent↗

PubMedDate not supplied

Image file formats: past, present, and future.

Despite the rapid growth of the Internet for storage and display of World Wide Web-based teaching files, the available image file formats have remained relatively limited. The recently developed portable networks graphics (PNG) format is versatile and offers several advantages over the older Internet standard image file formats that make it an attractive option for digital teaching files. With the PNG format, it is possible to repeatedly open, edit, and save files with lossless compression along with gamma and chromicity correction. The two-dimensional interlacing capabilities of PNG allow an image to fill in from top to bottom and from right to left, making retrieval faster than with other formats. In addition, images can be viewed closer to the original settings, and metadata (ie, information about data) can be incorporated into files. The PNG format provides a network-friendly, patent-free, lossless compression scheme that is truly cross-platform and has many new features that are useful for multimedia and Web-based radiologic teaching. The widespread acceptance of PNG by the World Wide Web Consortium and by the most popular Web browsers and graphic manipulation software companies suggests an expanding role in the future of multimedia teaching file development.

Computer-Assisted Instruction↗

PubMedDate not supplied

Imaging and clinical characteristics of temporal bone meningioma.

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.

Adolescent↗