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ABSTRACT: OBJECTIVES/HYPOTHESIS: To describe the presentation and clinical course of cerebellopontine angle (CPA) and internal auditory canal (IAC) lipomas. STUDY DESIGN: Retrospective cohort study at a tertiary academic referral center. METHODS: All patients presenting with a CPA or IAC mass radiographically consistent with a lipoma on high-resolution magnetic resonance imaging (MRI) were identified. Data including presenting symptomatology, tumor characteristics, management strategy, and patient course were collected. RESULTS: Between 1996 and 2012, 15 patients were diagnosed with a CPA or IAC lipoma at the authors' institution and were included in the analysis. The mean duration of radiological and clinical follow-up was 3.4 years and 5.1 years, respectively. Eight lesions were confined to the IAC, while seven involved the CPA. The median tumor size at diagnosis was 7.2 mm; one patient demonstrated tumor growth on serial MRI while the remaining subjects did not have radiological progression. The most common presenting symptoms were sensorineural hearing loss (40%) and tinnitus (33%); five patients were diagnosed after incidental discovery on MRI. Fourteen patients were managed with observation, while one subject underwent subtotal resection. None of the observed patients reported worsening symptoms at last follow-up. CONCLUSIONS: While rare, lipomas should be included in the differential diagnosis of CPA and IAC lesions. Owing to a generally benign clinical course and high morbidity associated with resection, microsurgery should only be considered in cases of definite tumor enlargement with intractable symptoms from mass effect. Careful radiological evaluation is critical for establishing an accurate diagnosis in order to prevent unnecessary morbidity associated with resection. LEVEL OF EVIDENCE: 2b.
The Laryngoscope 02/2013; · 1.75 Impact Factor
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ABSTRACT: OBJECTIVES/HYPOTHESIS: To describe the natural history of primary inner ear schwannomas (PIES) and evaluate management outcomes and relationship between PIES location, clinical presentation, and time to diagnosis. STUDY DESIGN: Retrospective chart review and systematic review of the literature. METHODS: Vestibular schwannoma confined to or arising from the inner ear were included. PIES classification was based on anatomic subsite(s) involved. Detailed clinical history and outcomes were recorded. RESULTS: In a systematic review (1933-2011), including 14 patients from the authors' institution (1999-2009), a total of 72 studies comprising 234 patients were evaluated. Mean follow-up was 32.8 ± 39.1 months (range, 0-183 months). The cochlea was the most commonly involved subsite (51%). Hearing loss was the most frequent presenting symptom (99%). Vertigo and abnormal balance were more common among tumors involving the vestibular system (P < .01). Average delay between symptom onset and diagnosis was 7.0 ± 8.0 years (median, 5 years; range, 0-40 years). Recent onset hearing loss was more likely to elicit an earlier diagnosis (P = .01). The majority of patients were observed without treatment (53%). Tumor progression was seen in 52% of patients. CONCLUSIONS: PIES are rare tumors and most commonly involve the cochlea. Tumor location is often associated with clinical presentation and correlates with delay between symptom onset and diagnosis. A watch-and-scan approach is the management strategy of choice in the absence of intractable vertigo or extensive tumor growth. The majority of patients report stable or improved symptoms over time, regardless of treatment.
The Laryngoscope 01/2013; · 1.75 Impact Factor
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ABSTRACT: To describe the incidence, pattern, and course of postoperative enhancement within the operative bed using serial gadolinium-enhanced magnetic resonance imaging (MRI) following vestibular schwannoma (VS) resection and to identify clinical and radiologic variables associated with recurrence.
Retrospective cohort study.
All patients who underwent microsurgical resection of VS between January 2000 and January 2010 at a single tertiary referral center were reviewed. Postoperative enhancement patterns were characterized on serial MRI studies. Clinical follow-up and outcomes were recorded.
During the last 10 years, 350 patients underwent microsurgical VS resection, and of these, 203 patients met study criteria (mean radiologic follow-up, 3.5 years). A total of 144 patients underwent gross total resection (GTR), 32 received near-total resection (NTR), and the remaining 27 underwent subtotal resection (STR); 98.5% of patients demonstrated enhancement within the operative bed following resection (58.5% linear, 41.5% nodular). Stable enhancement patterns were seen in 24.5% of patients, regression in 66.0%, and resolution in only 3.5% of patients on the most recent postoperative MRI. Twelve patients recurred a mean of 3.0 years following surgery. The average maximum linear diameter growth rate among recurrent tumors was 2.3 mm per year. Those receiving STR were more than nine times more likely to experience recurrence compared to those undergoing NTR or GTR (P < .001). Nodular enhancement on the initial postoperative MRI was associated with a 16-fold increased risk for future recurrence compared to those with linear patterns (P = .008). Among those with nodular enhancement on baseline postoperative MRI, a maximum linear diameter of ≥ 15 mm or volume of ≥ 0.4 cm(3) was associated with an approximate five-fold increased risk for future growth (P < .02).
Persistent nonspecific radiologic enhancement within the postoperative field is common, making the diagnosis of tumor recurrence challenging. Factors including completeness of resection and baseline postoperative MRI findings provide valuable information regarding risk for recurrence, which may assist the clinician in determining an appropriate postoperative MRI surveillance schedule. Future studies using standardized terminology and consistent study metrics are needed to further refine surveillance recommendations.
The Laryngoscope 02/2012; 122(2):378-88. · 1.75 Impact Factor
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ABSTRACT: The authors describe the unique occurrence of nodular enhancement within the fundus of the internal auditory canal (IAC) lateral to the preoperative radiological tumor margin following gross-total vestibular schwannoma (VS) resection.
The nature of the study was a retrospective chart review of records. The authors reviewed the cases of all patients who underwent microsurgical resection of a VS between January 2000 and January 2010 at a single tertiary referral center. Patients with incomplete resection, neurofibromatosis Type 2, and those with fewer than 2 postoperative MR images available for review were excluded. Postsurgical patients with IAC enhancement located lateral to the preoperative imaging-delineated tumor margin were identified. Lesion morphology was characterized on serial MR imaging studies. Clinical follow-up and outcomes were recorded.
Over the past decade, 350 patients underwent microsurgical VS resection. Of these, 16 patients met study criteria and were found to have postsurgical enhancement in the distal aspect of the IAC lateral to the imaging limits of the preoperative tumor margin on the first postoperative MR imaging study (37.5% women, median age 45 years). Initial MR imaging was performed at a mean of 3.1 months following surgery, and the mean radiological follow-up duration was 39.8 months (range 16.4-101.9 months). None of the 16 patients developed recurrence during the follow-up course.
In contrast to previous publications that have reported a high rate of recurrence in cases involving nodular enhancement within the original tumor bed, postoperative enhancement in the IAC lateral to the original tumor margin appears to carry much less risk for tumor recurrence. These findings may be helpful when counseling patients on the recommended frequency of postoperative follow-up imaging.
Journal of Neurosurgery 07/2011; 115(4):835-41. · 2.96 Impact Factor
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ABSTRACT: To compare electrode array position, and depth of insertion of the Cochlear Hybrid-L24 electrode array following traditional cochleostomy and round window (RW) insertion.
Prospective cadaveric temporal bone study.
Ten cadaveric temporal bones were implanted with the Hybrid-L24 electrode array; half were introduced through a RW approach, whereas the other half were inserted through a traditional scala tympani cochleostomy. A micro-CT scanner was then used to evaluate electrode position, intracochlear trauma, and depth of insertion.
All electrodes were inserted into the scala tympani without significant resistance. No electrodes demonstrated tip fold-over or through-fracturing of the osseous spiral lamina, basilar membrane, or spiral ligament. The average angular depth of insertion for all 10 electrodes was 252.4°. Compared to cochleostomy insertions, electrodes inserted through the RW more commonly acquired a proximal perimodiolar orientation, followed a more predictable course, and less commonly contacted critical soft tissue structures.
The results of this study demonstrate that the Hybrid-L24 electrode can be successfully inserted using a RW or traditional cochleostomy technique with minimal intracochlear trauma. Our data also suggests that with this model, RW insertions may provide particular advantages with respect to hearing preservation over the traditional cochleostomy approach.
The Laryngoscope 07/2011; 121(7):1508-16. · 1.75 Impact Factor
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ABSTRACT: Objectives/Hypothesis:To compare electrode array position, and depth of insertion of the Cochlear Hybrid-L24® electrode array following traditional cochleostomy and round window (RW) insertion.Study Design:Prospective cadaveric temporal bone study.Methods:Ten cadaveric temporal bones were implanted with the Hybrid-L24® electrode array; half were introduced through a RW approach, whereas the other half were inserted through a traditional scala tympani cochleostomy. A micro-CT scanner was then used to evaluate electrode position, intracochlear trauma, and depth of insertion.Results:All electrodes were inserted into the scala tympani without significant resistance. No electrodes demonstrated tip fold-over or through-fracturing of the osseous spiral lamina, basilar membrane, or spiral ligament. The average angular depth of insertion for all 10 electrodes was 252.4°. Compared to cochleostomy insertions, electrodes inserted through the RW more commonly acquired a proximal perimodiolar orientation, followed a more predictable course, and less commonly contacted critical soft tissue structures.Conclusions:The results of this study demonstrate that the Hybrid-L24® electrode can be successfully inserted using a RW or traditional cochleostomy technique with minimal intracochlear trauma. Our data also suggests that with this model, RW insertions may provide particular advantages with respect to hearing preservation over the traditional cochleostomy approach. Laryngoscope, 2011
The Laryngoscope 06/2011; 121(7):1508 - 1516. · 1.75 Impact Factor
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ABSTRACT: Computed tomography (CT) has long been considered the optimal imaging technique for the detection of cholesteatomas. However, this modality often lacks specificity, particularly in patients with an absence of definite bony erosion or a history of surgical excision. Several investigators have proposed magnetic resonance imaging with diffusion-weighted imaging (DWI) as a means of diagnosing the presence and extent of cholesteatomas, particularly when CT results are equivocal. The rationale for the use of DWI is that cholesteatomas demonstrate restricted diffusion and granulation tissue does not. In this retrospective study, we review our experience with 12 patients who had undergone DWI for evaluation of a mass in the middle ear, mastoid, or petrous apex. Ten of these patients had previously undergone middle ear surgery, 8 for cholesteatoma resection. On DWI, 9 patients demonstrated restricted diffusion. Of these, 8 patients underwent surgical resection, and all were found to have had a cholesteatoma. Of the 3 patients who had not demonstrated restricted diffusion on DWI, 2 did not undergo surgery and the other was found to have only chronic inflammation at surgery. Based on our limited experience, we believe that DWI can be useful in confirming the diagnosis of cholesteatoma. Moreover, it may alter patient management, particularly in patients whose previous tympanoplasty/mastoidectomy does not allow for an adequate clinical inspection of the middle ear cavity.
Ear, nose, & throat journal 04/2010; 89(4):E14-9. · 0.66 Impact Factor
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Neurology 03/2009; 72(7):671-3. · 8.31 Impact Factor
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ABSTRACT: OBJECTIVE: Arrested skull base pneumatization is a benign developmental variant that can be confused with significant skull base disease processes. This study reviews the imaging findings in 30 suspected cases of arrested skull base pneumatization. CONCLUSION: When encountering a nonexpansile lesion with osteosclerotic borders, internal fat, and curvilinear calcifications in the basisphenoid bone or adjacent skull base, radiologists should strongly consider the diagnosis of arrested pneumatization.
American Journal of Roentgenology 07/2008; 190(6):1691-6. · 2.78 Impact Factor
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ABSTRACT: To use the improved resolution available with 64-slice multidetector computed tomography (MDCT) in vivo to localize the cochlear implant electrode array within the basal turn.
Sixty-four-slice MDCT examinations of the temporal bones were retrospectively reviewed in 17 patients. Twenty-three implants were evaluated.
Tertiary referral facility.
All patients with previous cochlear implantation evaluated at our center between January 2004 and March 2006 were offered a computed tomographic examination as part of the study. In addition, preoperative computed tomographic examinations in patients being evaluated for a second bilateral device were included.
Sixty-four-slice MDCT examination of the temporal bones.
Localization of the electrode array within the basal turn from multiplanar reconstructions of the cochlea.
Twenty-three implants were imaged in 17 patients. We were able to localize the electrode array within the scala tympani within the basal turn in 10 implants. In 3 implants, the electrode array was localized to the scala vestibuli. Migration of the electrode array from scala tympani to scala vestibuli was observed in three implants. Of the 7 implants in which localization of the electrode array was indeterminate, all had disease entities that obscured the definition of the normal cochlear anatomy.
Sixty-four-slice MDCT with multiplanar reconstructions of the postoperative cochlea after cochlear implantation allows for accurate localization of the electrode array within the basal turn where normal cochlear anatomy is not obscured by the underlying disease process. Correlating the position of the electrode in the basal turn with surgical technique and implant design could be helpful in improving outcomes.
Ontology & Neurotology 09/2007; 28(5):658-62. · 1.90 Impact Factor
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ABSTRACT: Despite being introduced in the 1970s and 1980s, CT and MRI continue to be the primary imaging modalities for the temporal bone and skull base. Although the general concepts and physics remain the same, the images obtained currently are far superior. Augmenting these traditional modalities are nuclear medicine imaging techniques, functional imaging, and the fusion of different techniques. Advances in these areas are expanding our options and illuminating pathology in unique ways. As basic physiologic processes are better understood, new opportunities for novel imaging techniques should arise.
Otolaryngologic Clinics of North America 07/2007; 40(3):439-54, vii. · 1.65 Impact Factor
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ABSTRACT: Improved resolution available with 64-slice multidetector computed tomography (MDCT) could potentially be used clinically to localize the cochlear implant (CI) electrode array within the basal turn.
In CI surgery, the electrode array should be inserted into and remain within the scala tympani to avoid injury to Reissner's membrane and the scala media. Correlating the position of the electrode in the basal turn with surgical technique and implant design could be helpful in improving outcomes.
After a standard left mastoid exposure of the round window niche through the facial recess performed on a cadaver head, an electrode array from a Nucleus Softip Contour CI was fully inserted through a cochleostomy. The head was then scanned axially on a 64-slice MDCT with 0.4-mm slice thickness and reconstructed into the oblique axial, oblique coronal, and oblique sagittal planes of the cochlea. The temporal bone was then harvested and imaged on a microcomputed tomographic scanner using 20-microm slice thickness. Identical reconstructions were made and compared with the 64-slice images to confirm exact location of the electrode array.
The 64-slice MDCT accurately localized the electrode array to the scala tympani. This was best demonstrated in the oblique sagittal plane, identifying the electrode array in the posterior inferior portion of the basal turn, posterior to the spiral lamina.
This ex vivo validation study suggests that 64-slice MDCT has the potential to allow accurate localization of the CI electrode array within the basal turn of the cochlea.
Ontology & Neurotology 03/2007; 28(2):191-4. · 1.90 Impact Factor
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ABSTRACT: Anatomic definition of the membranous labyrinth in the clinical setting remains limited despite significant technological advances in magnetic resonance imaging (MRI). Recent developments in ultra-high resolution imaging for use in the research laboratory on small animals and pathologic specimens have given rise to the field of imaging microscopy. We have delineated for the first time the labyrinthine structures in a human temporal bone cadaver specimen using these novel techniques. This approach to the study of the middle and inner ear avoids tissue destruction inherent in histological preparations using standard light microscopy techniques. Part I of this series focused on bony middle and inner ear anatomy with MicrCT. In Part II, we present high-resolution MicroMR images to highlight the utility of this technique in teaching radiologists and otolaryngologists clinically relevant anatomy focusing on the membranous labyrinth. This anatomy can be further enhanced using 3D volume-rendered images. It is hoped that familiarity with these ex vivo anatomic techniques will encourage further developments in the field of high-resolution clinical imaging for patients with temporal bone pathologies.
Clinical Anatomy 10/2005; 18(6):409-15. · 1.29 Impact Factor
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ABSTRACT: We report five cases of symptomatic delayed cyst formation after radiosurgery for intracranial arterial venous malformations. Median time to discovery of the cysts following most recent radiosurgery was 59 months (range, 34-89 months). In all five patients, the radiation therapy-induced cysts exhibited tumefactive characteristics, including vasogenic edema, mass effect, and nodular enhancement. Despite these malignant features, these cystic lesions should be recognized as a benign complication of radiosurgery so that proper treatment (i.e., cystoperitoneal shunt surgery or excision) can be initiated.
American Journal of Neuroradiology 06/2005; 26(5):1152-7. · 2.93 Impact Factor
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ABSTRACT: The detection and localization of spinal dural arteriovenous fistulas (AVFs) remain diagnostic challenges. This study tested the hypothesis that elliptic centric contrast-enhanced MR angiography (MRA) can be used to detect spinal dural AVFs, predict the level of fistulas, and reduce the radiation dose and volume of iodinated contrast material associated with conventional angiography.
We examined 31 patients who presented with suspected spinal dural AVF between December 2000 and March 2004. All patients underwent MRA and conventional angiography. The effect of MRA on subsequent conventional angiography was assessed by analyzing total fluoroscopy time and volume of iodinated contrast material used.
At angiography, spinal dural AVFs were diagnosed in 22 of 31 patients, and MRA depicted an AVF in 20 of the 22 patients. MRA findings correctly predicted a negative angiogram in seven of nine cases. Of the 20 true-positive MRA results, the level of the fistula was included in the imaging volume in 14. In 13 of these 14 cases, MRA results correctly predicted the side and the level of the fistula to within one vertebral level. Fluoroscopy time and the volume of contrast agent was reduced by more than 50% in the 13 patients with a spinal dural AVF in whom MRA prospectively indicated the correct level.
Contrast-enhanced MRA can be used to detect spinal dural AVFs, predict the level of fistulas, and substantially reduce the radiation dose and volume of contrast agent associated with catheter spinal angiography.
American Journal of Neuroradiology 05/2005; 26(4):711-8. · 2.93 Impact Factor
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Mayo Clinic Proceedings 04/2005; 80(3):315. · 5.70 Impact Factor
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ABSTRACT: A case is presented of a huge GH/TSH secreting tumor and marked volumetric reduction in size with only one week of Octreotide
therapy. To our knowledge, this is the first reported case of such a dramatic volumetric response to short-term Octreotide
therapy.
Pituitary 03/2005; 8(2):89-91. · 1.83 Impact Factor
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ABSTRACT: A case is presented of a huge GH/TSH secreting tumor and marked volumetric reduction in size with only one week of Octreotide therapy. To our knowledge, this is the first reported case of such a dramatic volumetric response to short-term Octreotide therapy.
Pituitary 02/2005; 8(2):89-91. · 1.83 Impact Factor
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ABSTRACT: A case is presented in which a complex multicystic hemosiderin-containing lesion developed adjacent to a previously documented developmental venous anomaly (venous angioma). This lesion had the characteristic MR imaging appearance of a cavernous malformation. Follow-up MR imaging demonstrated a decrease in both the size and complexity of this lesion, which suggests at least a portion of the lesion was due to sequelae of hemorrhage. This case further supports the association of a de novo, hemosiderin-containing lesion in association with developmental venous anomaly. Implications of these findings are that the commonly seen "cavernous malformations" in association with developmental venous anomaly are acquired lesions, and not congenital in origin. A review of the literature discussing the etiology of cavernous malformations and their reported association with the developmental venous anomaly is provided.
American Journal of Neuroradiology 02/2005; 26(1):156-9. · 2.93 Impact Factor
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ABSTRACT: Anatomic definition of the middle ear and bony labyrinth in the clinical setting remains limited despite significant technological advances in computed tomography (CT). Recent developments in ultra-high resolution imaging for use in the research laboratory on small animals and pathologic specimens have given rise to the field of imaging microscopy. We have taken advantage of this technique to image a human temporal bone cadaver specimen to delineate middle ear and labyrinthine structures, only seen previously using standard light microscopy. This approach to the study of the inner ear avoids tissue destruction inherent in histological preparations. We present high-resolution MicroCT images of the middle ear and bony labyrinth to highlight the utility of this technique in teaching radiologists and otolaryngologists clinically relevant temporal bone anatomy. This study is not meant to function as a complete anatomic atlas of the temporal bone. We have selected several structures that are routinely delineated on clinical scanners to highlight the utility of imaging microscopy in displaying critical anatomic relationships in three orthogonal planes. These anatomic relationships can be further enhanced using 3D volume rendering.
Clinical Anatomy 12/2004; 17(8):607-12. · 1.29 Impact Factor
