Download ASHNR 2016 - Call for Abstracts

(SPS1_101) Chondrosarcoma Conundrum: A Retrospective Institutional Review of Pretreatment
Cross-Sectional Neuroimaging in Histopathologically-Proven Head & Neck Chondrosarcomas
Start Time: 1:17 PM
Author(s)
Ted A. Seltman, M.D.
Radiology Resident
Department of Radiology & Imaging Sciences, Indiana University School of Medicine
Role: Author
Nicholas A. Koontz, M.D.
Assistant Professor of Radiology
Department of Radiology & Imaging Sciences, Indiana University School of Medicine
Role: Author
Stephen F. Kralik, M.D.
Assistant Professor of Radiology
Department of Radiology & Imaging Sciences, Indiana University School of Medicine
Role: Author
Kristine M. Mosier, DMD, Ph.D.
Associate Professor of Radiology
Department of Radiology & Imaging Sciences, Indiana University School of Medicine
Abstract Details
Purpose:
The purpose of this project is to systematically evaluate the CT and MRI appearance of
histopathologically-proven chondrosarcomas of the head and neck (H&N) and determine potential factors
predisposing to variability in imaging appearance
Materials & Methods:
We performed an IRB-approved, HIPAA-compliant retrospective review of the pathology database (2001
- 2016) at our institution for all histopathologically-proven primary chondrosarcomas of the H&N. We
included patients with histopathologically-proven chondrosarcomas of all H&N sites with cross-sectional
(CT and/or MRI) neuroimaging at initial presentation, excluding those with prior surgery, chemotherapy,
radiation therapy, residual/recurrent disease from prior treatment, or patients without pre-treatment
imaging. Four reviewers of varying levels of experience independently scored the pre-treatment imaging
exams for several findings pertaining to chondrosarcomas, including freehand region of interest for CT
attenuation and MRI ADC map analysis. Normalized tumor-to-medulla ADC ratios (ADCratio = ADClesion
/ ADCmedulla) were generated in order to obviate variance in ADC values between scanners, magnetic
field strengths, and matrix sizes. Demographic features of age, gender, tumor location, size, histologic
grade, magnetic field strength, and subsequent treatment strategies were recorded. Wilcoxon signedrank test was performed utilizing Minitab 17 (Minitab, Inc., State College, Pennsylvania).
Results:
15 patients (age range, 25-77 yrs; mean age, 47.4 yrs; female, 10; male, 5) with 15 total
chondrosarcomas met inclusion criteria. Pretreatment imaging included CT (n = 14), MRI (n = 12), or
both (n = 10). 47% of chondrosarcomas were petroclival (n = 7) in location, but lesions were also
observed in the sinonasal (n = 2), sellar/suprasellar (n = 2), spinal epidural (n = 2), sphenoid wing (n = 1),
and cricoid (n = 1) regions. Two-thirds of all chondrosarcomas originated on the right side (n = 10), with
20% midline (n = 3) and 13.3% originating on the left (n = 2). While the vast majority demonstrated some
degree of calcification (93%, n = 13), most commonly in flecks of residual peripheral calcification from
osseous destruction (67%, n = 10), only 57% (n = 8) showed true matrix mineralization on CT.
Specifically, petroclival chondrosarcomas were significantly less likely to have matrix mineralization
(28.6%, n = 2) relative to all others (85.7%, n = 6) (Wilcoxon signed-rank, Z = 3.04; p = 0.0012). All
chondrosarcomas demonstrated a high mean ADC value (1.85 x 10-3 mm2/sec; range, 1.23 - 2.27 x 103 mm2/sec) and mean ADC ratio (2.1; range, 1.8 - 2.7).
Conclusion:
Chondrosarcomas of the H&N demonstrate a strong female (67%), right-sided (67%), and petroclival
(47%) predominance. The common adage of 50% of H&N chondrosarcomas showing matrix
mineralization may be accurate when considering all comers (57%, n = 8), but does not hold true for
petroclival chondrosarcomas, which have calcified matrix in only 28% (n = 2). Additionally, mean ADC
values and normalized ADC ratios of chondrosarcomas are invariably much higher than previously
reported malignant thresholds for other H&N tumors.
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(SPS1_102) Role of Personalized 3-dimensional Printed Models in Pediatric Skull Base Tumor Surgical
Planning
Start Time: 1:25 PM
Author(s)
Sanjay P. Prabhu, MBBS, FRCR
Staff Pediatric Neuroradiologist
Boston Children's Hospital
Role: Author
Peter Weinstock, MD
Director and Anesthesia Chair, Simulation Program
Boston Children's Hospital
Role: Author
Katie Livingston, ME
Simulation Specialist II, SIMPeds 3DPrint Lead
Boston Children's Hospital
Role: Author
Salim Afshar, MD
Attending Oral and Maxillofacial Surgeon
Boston Children's Hospital
Role: Author
Carolyn R. Rogers-Vizena, M.D.
Attending maxillofacial surgeon
Boston Children's Hospital
Role: Author
Edward Smith, MD
Attending Neurosurgeon
Boston Children's Hospital
Role: Author
Reza Rahbar, MD
Attending Otolaryngologist
Boston Childrens Hospital
Abstract Details
Purpose:
1. To describe the steps in creating a 3D printed model of pediatric skull base tumors.
2. To evaluate value of 3D printing in presurgical planning of skull base tumors including value of the 3D
print in the surgical plan including development of the operative plan, improving multidisciplinary
collaboration, improving comfort and confidence levels of the surgical operator and documenting if 3D
printed model recapitulates anatomy actually encountered during surgery.
Materials & Methods: 3D printed models were created for surgical planning from imaging studies (CT and
MRI) in 5 patients with various skull base tumors in different locations based on requests from the
surgical team. Imaging studies were segmented using the Mimics 17.0 software (Materialise N.V.,
Leuven, Belgium) and printed on a Stratasys Connex-500 printer by the in-house 3D print team at our
hospital. Imaging study used to print was based on the tumor characteristics and location. Osseous
anatomy was printed using CT and soft tissue anatomy was printed using MRI, with fusion accomplished
using the 3-Matic software (Materialise N.V., Leuven, Belgium). Multiple resins and colors were printed
simultaneously allowing specific anatomic focus. Intraoperative validation of model fidelity was performed
using a combination of perioperative imaging, surgical filming and post-hoc analysis of models with
intraoperative photography.
Results: 5 pediatric patients (ages 0-16 years) were studied as initial proof-of-principle cases. The tumor
type and location included 2 chordomas ( 1 along the petrous temporal bone and 1 midline chordoma
along the clivus, an infratemporal rhabdomyosarcoma, a neuromelanotic tumor of infancy and a
craniopharyngioma. Use of 3D models was associated with improved communication between various
multidisciplinary staff involved in the procedures based on questionnaires sent to respondents compared
to matched controls. Post procedural interviews and questionnaires indicated that patient families,
trainees and surgeons indicated that use of 3D printing was novel and that the 3D model increased
understanding of the tumor location and helped in choosing the most optimal approach for surgical
resection. In one case, the surgeon reported greater understanding of the geometry and depth of the
lesion allowing better access to the lesion in the operating room.
Conclusions:
Patient-specific 3D printed models of pediatric skull base tumors can be constructed with high fidelity.
These models can assist with patient education, pre-procedural simulation for trainees and physicians,
and serve as useful intraprocedural reference tools. Our proof-of-principle series demonstrates, for the
first time, confirmation of model accuracy using intraprocedural assessment and potential benefits
through improved multidisciplinary collaboration, better understanding of the geometry and depth of the
lesion and in turn, may result in potentially shortened operative time and reduced complications.
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(SPS1_103) The trochlear groove: a useful anatomic landmark for identifying cranial nerve IV
Start Time: 1:33 PM
Author(s)
Paul M. Bunch, MD
Radiology Resident
Brigham and Women's Hospital, Harvard Medical School
Role: Author
Hillary R. Kelly, MD
Assistant Professor of Radiology
Massachusetts General Hospital, Massachusetts Eye and Ear, Harvard Medical School
Role: Author
David A. Zander, MD
Instructor of Radiology
Massachusetts Eye and Ear, Harvard Medical School
Role: Author
Hugh D. Curtin, MD
Chief of Radiology, Professor of Radiology
Massachusetts Eye and Ear, Harvard Medical School
Abstract Details
Purpose:
Historically, imaging cranial nerve IV has been very difficult. In research settings, high-resolution
magnetic resonance (MR) sequences have reliably demonstrated cranial nerve IV in healthy volunteers;
however, long acquisition times make these sequences impractical for routine clinical use.
Recent neurosurgical studies report that the sites at which cranial nerve IV contacts and subsequently
pierces the tentorium represent reliable anatomic landmarks for intra-operative nerve identification.
Coronal 2D T2-weighted fast spin echo with driven equilibrium (coronal T2 DRIVE) is a fluid-sensitive MR
sequence commonly performed during sinus MR examinations at our institution. Cranial nerve IV can be
identified within a groove along the inferior aspect of the tentorium on clinical images obtained with this
sequence (Figure 1), and we refer to this shallow depression as the “trochlear groove.”
We hypothesize that knowledge of this anatomic landmark will facilitate identification of cranial nerve IV
in routine clinical practice.
The purposes of this study are to 1) describe the MR appearance of the trochlear groove and 2) test our
hypothesis regarding the utility of this landmark for identifying cranial nerve IV.
Materials and Methods:
For this retrospective study, 32 consecutive MR examinations of the sinuses performed between
12/1/2015 and 4/1/2016 were reviewed. All examinations were performed on a 3.0 Tesla scanner using
an 8-channel head coil.
Patient characteristics, study indications, and sequence acquisition times were recorded. Three readers
performed independent assessments of groove and nerve visibility. Discrepancies were resolved by
consensus. When visible, measurements of the groove were taken. Statistical analyses were performed.
Results:
Seven studies not containing the sequence of interest were excluded, yielding a study group of 25
patients and 50 sides.
The mean patient age was 56.2 years (SD 13.8; range 30–85), and there were 16 females (64%) and 9
males (34%). Sinonasal carcinoma (n=6) and inverted papilloma (n=4) were the most frequent
indications. The mean acquisition time was 3.9 minutes (SD 0.61; range 2.9—5.0).
Interobserver agreement was 78% for groove visibility and 68% for nerve visibility.
Following consensus review, the trochlear groove was visible in 44/50 sides (88%). The groove was
located a mean of 1.41 mm (SD 0.44; range 0.67–2.39) inferolateral to the tentorial free edge, and the
mean groove depth was 0.49 mm (SD 0.15; range 0.22–0.78).
Overall, cranial nerve IV was visible in 36/50 sides (72%). When the trochlear groove was visible, cranial
nerve IV was identified in 35/44 sides (80%) in contrast to 1/6 sides (17%) with no visible groove. This
observed difference in proportions was statistically significant (p=0.0047, Fisher’s exact test).
Conclusions:
The trochlear groove is a frequently-present shallow groove along the inferior aspect of the tentorium
near the free edge along which cranial nerve IV travels en route to the cavernous sinus. Identification of
the groove improves chances of identifying cranial nerve IV using a fluid-sensitive sequence performed in
routine clinical practice.
These findings would be expected to improve diagnostic confidence and diagnostic accuracy in the MR
evaluation of patients with suspected cranial nerve IV congenital absence (Figure 2).
(SPS1_104) Cranial nerve leptomeningeal carcinomatosis: Patterns of disease, clinical presentation,
and frequency of involvement in metastatic disease.
Start Time: 1:41 PM
Author(s)
Elizabeth L. Ryals, MD
PGY- 2 Radiology Resident
University of Utah Health Sciences Center
Role: Author
Richard H. Wiggins, III., MD
Professor Diagnostic Neuroradiology
University of Utah Health Sciences Center
Role: Author
Min Park, M.D.
Assistant Professor Neurosurgery; Adjunct Associate Professor Radiology and Imaging Sciences
University of Utah Health Sciences Center
Role: Author
Alison Crum, M.D.
Assistant Professor Ophthalmology/Visual Sciences; Adjunct Assistant Professor Neurology
University of Utah Health Sciences Center
Role: Author
Edward P. Quigley, III, M.D., Ph.D
Associate Professor Radiology and Imaging Sciences
University of Utah Health Sciences Center
Abstract Details
Purpose:
To examine the MR appearance of leptomeningeal carcinomatosis involving cranial nerves.
To characterize the clinical presentations of cranial nerve leptomeningeal carcinomatosis.
Describe the cranial nerves most commonly involved and discuss potential mechanisms.
Materials/Methods:
IRB approved retrospective case review over 5 years was performed using analytical informatics search tool.
All cases of intracranial leptomeningeal carcinomatosis or cranial nerve enhancement were searched on
gadolinium enhanced MRI of the head, skull base, or head and neck. Retrograde perineural spread of disease
was excluded. Clinical presentation and symptoms and primary malignancy was obtained from EMR.
Leptomeningeal carcinomatosis involving cranial nerves was characterized by post-contrast T1 enhancement
at root exit zones or cisternal segments of cranial nerves. Thickening and nodularity of cranial nerve segments
was visualized on high resolution T2 volumetric sequences.
Results:
24 cases of leptomeningeal carcinomatosis were identified. Of these 24 cases, 16 cases of cranial nerve
involvement were detected. Involvement of the root exit zone, cisternal, or canalicular segments were
identified. The most common malignancies were melanoma, breast and lung cancer. The most frequently
involved cranial nerves were CN VII/VIII followed by CN V and CN III.
Conclusions:
Leptomeningeal carcinomatosis is an increasingly common complication in cancer patients with advanced
disease. Cranial nerve enhancement and nodularity is an important part of the neuroradiologist' search
pattern, especially when the given indication is metastatic disease. Axial and coronal thin section dedicated
views of the skull base are helpful. Some cranial nerves may be more commonly involved than others. CSF
flow dynamics, arachnoid reflections, and size of cisternal segments may play a role in the seeding of these
vital structures. This project reinforces the importance of keeping the cranial nerves in the metastatic search
pattern.
(SPS1_105) Diagnostic Utility of Compressed Sensing SPACE for IAC MRI Screening Protocols
Start Time: 1:49 PM
Author(s)
Mikell Yuhasz, MD, MHS
Radiology Resident
NYU Langone Medical Center, Department of Radiology
Role: Author
Michael Hoch, MD
Instructor
NYU Langone Medical Center, Department of Neuroradiology
Role: Author
Mari Hagiwara, MD
Assistant Clinical Professor
New York Langone Medical Center, Department of Neuroradiology
Role: Author
Mary Bruno
Radiology Technician
NYU Langone Medical Center, Department of Radiology
Role: Author
James Babb
Radiology Statistician
NYU Langone, Department of Radiology
Role: Author
Thomas Roland, MD, FACS
Mendik Foundation Chairman Department of Otolaryngology
NYU Langone Medical Center, Department of Otolaryngology
Role: Author
Timothy Shepherd, MD, PhD
Assistant Clinical Professor
New York Langone Medical Center, Department of Neuroradiology
Abstract Details
Background: Sensorineural hearing loss and dizziness are common clinical indications for MRI studies
that use high-resolution T2-weighted sequences, such as T2 SPACE, to rule out pathology in the
cerebellopontine angle, internal auditory canal and fluid-filled inner ear structures. These sequences
require 4-5 minutes additional scanning time, but have a low yield for structural abnormalities. MRI data
is sparse such that incoherent, sub-Nyquist sampling with non-linear reconstruction can generate
potentially clinically diagnostic images much faster – this is called compressed sensing (CS). We tested
this hypothesis with an under-sampled T2 SPACE sequence in MRI IAC protocols.
Material and Methods: With institutional review board approval, an enriched sample of 72 patients (37
male, 51.4 ± 16.4 yrs, 23 positive cases) had 3-T contrast MRI that included 500-μm isotropic routine and
CS 3D T2 SPACE sequence (latter: 4x undersampling, regularization = 0.005, time = 50 sec). Unilateral,
multiplanar reconstructions for both T2 SPACE sequences were separated, then placed into mixed
folders for independent, blinded review by 3 board-certified neuroradiologists in 2 sessions separated by
4-6 weeks. Visualization of the cochlea, vestibule, internal auditory canal (IAC) and cerebellopontine
angle were compared using ordinal scales [unacceptable (1), poor (2), acceptable (3), good (4) and
excellent (5)]. We compared lesion detection and user-measured maximal axial lesion size. Unpaired
Mann-Whitney tests determined if there were statistical differences between routine and CS SPACE.
Results: CS SPACE acquisitions for IAC MRI screening protocols reduced sequence scan time 80% from
250 to 50 seconds. Overall, radiologists visually preferred the conventional T2 SPACE, but not by much
(4.5±0.5 vs 3.8±0.6 ordinal score, P < 0.01). There also were 9-18% higher evaluation scores for image
quality in the cochlea, vestibular apparatus and cerebellopontine angle using conventional T2 SPACE (P
< 0.01), but assessment of the IAC was statistically indistinguishable. Note the mean assessment score
for the CS SPACE sequence was between 3.8-4.2 (where “4” = good diagnostic quality) and no studies
received poor or nondiagnostic scores. No abnormal mass was missed with either sequence.
Radiologists using CS SPACE equally under- and overestimated mass maximum axial dimension when
present (32% cases with mean size 5.3 ± 3.8 mm) with a mean absolute size difference between the two
acquisitions of only 0.6 ± 0.4 mm.
Conclusions: This study demonstrates that novel CS techniques can be used to accelerate the T2
SPACE component of routine screening IAC MRI protocols by 80% while preserving adequate diagnostic
image quality. Ordinal, Likert scale evaluations indicate that radiologists found the images slightly less
satisfying overall, but the key diagnostic features were preserved. Routine SPACE may in fact be more
susceptible to head and pulsatile motion. Limitations of the current study include reviews blinded to
companion contrast MRI sequences, use of an enriched sample for the presence of mass and the
absence of uncommon congenital inner ear malformations in this adult population. Future work will focus
on future improvements in CS image reconstruction – it should be noted that CS also can be used
conversely to increase spatial resolution for inner ear abnormalities.
(SPS1_106) Utility of Using a Constructive Interference in Steady State Sequence (CISS) Alone For The
Follow-Up Evaluation of Vestibular Schwannomas
Start Time: 1:57 PM
Author(s)
Karen Buch, MD
Neuroradiology Fellow
Massachusetts General Hospital, Harvard Medical School
Role: Author
Mary Beth Cunnane, MD
staff radiology
MGH
Role: Author
Konstantina M Stankovic, MD
staff otolaryngologist
MGH
Role: Author
Hugh D. Curtin, MD
Chief of Radiology, Professor of Radiology
Massachusetts Eye and Ear, Harvard Medical School
Abstract Details
Purpose: Patients with vestibular schwannomas often undergo annual or biannual contrast-enhanced
MRI evaluations to follow lesion size and extent. Concern regarding deposition of gadolinium-based
contrast agents in the brain has resulted in re-evaluation for the need of contrast for these frequent
follow-up examinations. The development of high-resolution T2 weighted sequences such as CISS has
been documented in the literature to accurately assess schwannoma size in on non-contrast MRI exams.
The purpose of this study was to evaluate the necessity of contrast enhanced scans for the detection of
incidental findings in patients undergoing surveillance imaging for vestibular schwannomas.
Methods & Materials: This was a retrospective, IRB approved study at a subspecialty hospital. MRI
exams for vestibular schwannomas included diffusion imaging, axial T2 FLAIR, pre- and post-contrast
axial and coronal images through the temporal bones, and a CISS sequence. The images and radiology
report were reviewed for the presence of incidental findings and the clinical significance score ranging
from 0-3 was assigned. A score of ‘0’ denoted no incidental findings, a ‘1’ indicated an incidental finding
with no associated clinical significance, a ‘2’ delineated a finding needing follow-up
imaging/management, and a ‘3’ notes a finding which requires urgent management.
Results: A total of 251 exams were reviewed with a mean surveillance of 6.7 years (range 1-month to 18
years, standard deviation 4.5 years). 30 of 251 patients (12%) carried a diagnosis of neurofibromatosis
type-2. Incidental findings were seen in 80 patients (68%) with 171 patients (68%) having no incidental
findings (grade 0). A clinical significance score of 1 was seen in 64 patients with 34 having sinus disease,
18 with chronic white matter changes, 5 with arachnoid cysts, 3 with meningiomas, 2 with pituitary
Rathke' cleft cysts, 2 with Tornwaldt cysts. A clinical significant score of 2 was seen in 8 patients
including 1 patient with a cystic parotid gland lesion, 1 with a pituitary mass, 1 with a dural metastasis, 3
with abnormal signal intensity in the semicircular canals and cochlea, and 2 with intracranial cavernomas.
A clinical significance score of 3 was seen in 2 patients, 1 with an acute infarction and 1 with an active
demyelinating plaque. Of the 251 MRI examinations reviewed, there were no findings on the postcontrast images which had no correlate on the additional non-contrast MRI sequences.
Discussion: It has already been established that non-contrast sequences allow accurate evaluation of
progression of vestibular schwannomas. Our results demonstrate that non-contrast images are also
sufficient for the detection of additional findings which may be identified in these patients. In patients
requiring multiple follow-up MR examinations for vestibular schwannoma surveillance, the post-contrast
images may be omitted.
i Ozgen B1, Oguz B, Dolgun A. Diagnostic Accuracy of the Constructive Interference in Steady State
Sequence Alone for Follow-up Imaging of Vestibular Schwannomas. AJNR 2009 May;30(5):985-91.
(SPS1_107) Classifying the Large Vestibular Aqueduct: Morphometry to Audiometry
Start Time: 2:05 PM
Author(s)
Mai-Lan Ho, MD
Assistant Professor of Neuroradiology
Mayo Clinic
Role: Author
Nicholas Deep, MD
Resident in Otolaryngology
Mayo Clinic
Role: Author
Matthew Carlson, MD
Assistant Professor of Otolaryngology
Mayo Clinic
Role: Author
Joseph Hoxworth, MD
Assistant Professor of Radiology
Mayo Clinic
Role: Author
Colin Driscoll, M.D.
Physician
Mayo Clinic
Role: Author
Brian Neff, MD
Associate Professor of Otolaryngology
Mayo Clinic
Role: Author
Jack Lane, MD
Neuroradiologist
Mayo Clinic
Abstract Details
PURPOSE:
Large vestibular aqueduct (LVA) is a heterogeneous group of inner ear malformations involving
enlargement of the endolymphatic duct and sac. Several theories exist regarding the mechanisms of
hearing loss and include hyperosmolar reflux of endolymph, third window acoustic transmission, and
associated inner ear anomalies. Anatomically, LVA can occur in isolation or in association with
cochleovestibular dysplasia (incomplete partition type II). LVA morphology also varies widely, with
numerous proposed classifications in the otorhinolaryngology literature. We sought to evaluate the
relationship of LVA morphology and associated inner ear anomalies to clinical audiometric findings.
MATERIALS AND METHODS:
We queried the radiology information system for LVA diagnosed on temporal bone CT and/or internal
auditory canal MRI between 1999-2016. Exclusion criteria included nonavailability of preoperative
imaging and/or audiometry, syndromic diagnosis, and significant middle ear pathology. The remaining
cases were retrospectively reviewed to classify the morphology of LVA, as well as the presence of
associated inner ear anomalies (cochlea, vestibule, semicircular canals, jugular bulb).
LVA morphology was based on both visual and quantitative criteria [Figure 1]:
1. Type I, filiform: VA mildly larger than PSCC. By measurement, meets one or both of Cincinnati criteria
(midpoint > 0.9 mm, operculum > 1.9 mm).
2. Type II, tubular: VA diffusely enlarged, including midpoint and aperture. Midpoint > 50% of aperture.
3. Type III, funneled: VA flared toward operculum, with enlarged aperture. Midpoint < 50% of aperture.
Audiograms were reviewed for severity of sensorineural hearing loss (SNHL) [overall score 0-3]; as well
as the presence of an air-bone gap (ABG).
RESULTS:
A total of 189 patients (434 ears) were included in the study, of which CT was performed for 278 ears
and MR for 189. Age distribution was bimodal, with peaks at 6 and 49 years. Gender prevalence was
44% male and 56% female, showing greater female preponderance with age.
Distribution of LVA morphology was 45% filiform, 11% tubular, and 44% funneled. Higher grades of LVA
were mildly correlated with cochleovestibular malformations (R = 0.380, P = 0.0000). Age and gender did
not correlate significantly with radiologic findings, based on Mann-Whitney U and Pearson correlation.
Based on Spearman’s rank-order correlation, LVA morphology was a moderately strong predictor of
SNHL severity (R = 0.660, p = 0.0000) and ABG (R = 0.711, P = 0.0000) at audiometry. Presence of
inner ear anomalies was a moderate, though less robust and non-independent, predictor of both outcome
measures (R = 0.384, P = 0.0006; R = 0.382, P = 0.0023).
CONCLUSIONS:
We introduce a morphometric classification of LVA with clinical validation by audiometry. More severe
forms of LVA are more likely to present with associated inner ear malformations, and are moderately
strong predictors of SNHL and ABG at audiometry. For outliers with type III LVA and normal audiometry,
this association raises concern for sudden or progressive hearing loss during the patient’s lifetime. This
work adds to a growing body of literature highlighting the multifactorial and complex etiology of hearing
loss in LVA.
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(SB_04) Eustachian Tube Lipoblastoma: A Rare Entity in an Unusual Location
Start Time: 2:13 PM
Author(s)
Jason R. Fredriksen, MD
Neuroradiology Fellow
Mayo Clinic - Rochester, MN
Role: Author
Jack Lane, MD
Neuroradiologist
Mayo Clinic
Role: Author
Karl Krecke, MD
Neuroradiologist
Mayo Clinic
Role: Author
Cara Cockerill, M.D.
Physician
Mayo Clinic
Role: Author
Colin Driscoll, M.D.
Physician
Mayo Clinic
Abstract Details
Purpose: This exhibit highlights the first reported case of a lipoblastoma arising in the eustachian tube. We
review the anatomy and embryology of the eustachian tube, and discuss the pathophysiology and imaging
appearance of lipoblastomas.
Case Description: A 13 month-old male presented for evaluation of an enlarging left ear mass, originally noted
at 4 months of age. Several rounds of antibiotic therapy were administered for presumed otitis media. Hearing
was presumed normal, although formal screening had not been performed. Otoscopy revealed a polypoid
mass filling the EAC. Imaging demonstrated a fat-containing mass in the eustachian tube, which was resected
via post-auricular approach. Pathology demonstrated benign appearing fat with a focal area of myxoid change
suggesting a maturing lipoblastoma.
Imaging: CT demonstrates a fat-containing mass in the left eustachian tube, extending from the bony EAC
toward the torus tubarius. The left middle ear and mastoid air cells are opacified, without ossicular erosion.
MRI shows a correlating T1 hyperintense tubular mass with signal loss on fat-saturated sequences, confirming
the presence of macroscopic fat. No abnormal gadolinium enhancement.
Discussion: The eustachian tube is derived from the first pharyngeal pouch and the second endodermal
pouch, which together comprise the tubotympanic sulcus. The lateral portion gives rise to the tympanic cavity,
with the medial portion developing into the eustachian tube proper. Structurally, the eustachian tube consists
of a lateral bony portion and a medial fibrocartilaginous portion. The junction between these segments is the
isthmus, and forms the narrowest portion of the eustachian tube. Medially, the tube terminates in the lateral
nasopharyngeal wall at the level of the inferior nasal concha. An elevated ridge of fibrocartilage at the base of
the tube gives rise to the torus tubarius. A mucosal reflection along the distal longus coli muscle forms the
fossa of Rosenmüller, which lies immediately posterosuperior to the torus tubarius. These structures serve as
anatomic landmarks on cross-sectional imaging studies, and together flank the ostium of the eustachian tube.
Lipoblastomas are rare, benign mesenchymal tumors which arise from embryonic white fat. Most cases occur
before the age of 3, with approximately 40% diagnosed in the first year of life. While these tumors do not
exhibit aggressive behavior or metastasize, they can become symptomatic from mass effect due to
progressive growth. The majority of these tumors occur in the extremities, with only a small minority occurring
in the head or neck. Lipoblastomas mimic benign lipomas on imaging. On CT, they appear as circumscribed
fat-attenuation masses. On MRI, lipoblastomas are hyperintense on both T1 and T2 weighted FSE
sequences, demonstrate signal loss on fat-saturated images, and do not enhance on post-gadolinium images.
The diagnosis of lipoblastoma is made at histopathology, where the presence of myxoid matrix and fibrous
septae suggest the diagnosis. Left unresected, lipoblastomas eventually differentiate into mature lipomas.
While these lesions are benign, the standard treatment is complete surgical resection. Long-term prognosis is
excellent, with variable 5-year local recurrence rates ranging from 10-25%.
(TB_12) Lateralization of the ICA associated with cochlear carotid dehiscence: three cases.
Start Time: 2:17 PM
Author(s)
Julie Guerin, MD
neuroradiology fellow
Mayo Clinic, Rochester, MN
Role: Author
Jack Lane, MD
Neuroradiologist
Mayo Clinic
Abstract Details
Lateralized internal carotid artery (ICA) is a rare petrous ICA variant in which the ICA enters the skull base
more posterolateral to the cochlea than normal with protrusion into the anterior mesotympanum. This
anomalous course, specifically defined as the ICA genu positioned lateral to the vertical aspect of the bony
cochlear labyrinth, leads to a reduction in the normal carotid canal–cochlear interval. Carotid-cochlear
dehiscence (CCD) is a rare developmental abnormality previously described independently from an
anomalous ICA course. Although CCD may be asymptomatic, common associated symptoms include both
sensorineural and conductive hearing loss and pulsatile tinnitus. The purpose of this educational exhibit is to
review the imaging findings of these anomalies when seen together, to demonstrate the difference in courses
between lateralized and aberrant ICA and to emphasize that appropriate recognition is important for
prevention of vascular injury in future surgical interventions.
We feature three patients with both lateralized ICAs and associated frank CCD. The first patient is a 64 yearold woman with a longstanding history of sensorineural hearing loss on the left. Temporal bone CT revealed
lateralized left ICA with focal dehiscence with the middle and apical turns of the left cochlea. The second
patient, a 63 year-old man, presented with left conductive hearing loss, right sensorineural hearing loss and
bilateral tinnitus. Temporal bone CT showed bilateral lateralized ICAs with focal dehiscence of the apical turns
of the cochlea. The third patient is a 72 year-old man who was being evaluated for temple and jaw pain and
received imaging for possible giant cell arteritis. He was incidentally found to have a lateralized left ICA with
focal dehiscence between the carotid canal and the middle turn of the cochlea.
In summary, lateralized ICA is an anomalous ICA course distinct from the more familiar aberrant ICA that
predisposes to CCD. In the limited prior reports of CCD, there is no reported association with ICA
lateralization. Likewise, prior descriptions of lateralized ICA do not adequately distinguish between thinning
and dehiscence of the carotid–cochlear interval. Our case series demonstrates frank carotid-cochlear
dehiscence associated with lateralized ICA. Although both sensorineural and conductive hearing loss has
been reported, associated conductive loss suggests a possible “third window” effect. Proper recognition of
these associated anomalies may have diagnostic implications in patients being evaluated for hearing loss and
tinnitus and for prevention of vascular injury during subsequent surgical interventions.
1. Glastonbury, C.M., et al., Lateralized petrous internal carotid artery: imaging features and distinction from
the aberrant internal carotid artery. Neuroradiology, 2012. 54(9): p. 1007-13.
2. Lund, A.D. and S.D. Palacios, Carotid artery-cochlear dehiscence: a review. The Laryngoscope, 2011.
121(12): p. 2658-60.
3. Young, R.J., et al., The cochlear-carotid interval: anatomic variation and potential clinical implications.
AJNR. American journal of neuroradiology, 2006. 27(7): p. 1486-90.
(TB_11) Spontaneous Otogenic Pneumocephalus presenting with Intraventricular Air
Start Time: 2:21 PM
Author(s)
James G. Naples, MD
ENT Resident
UCONN
Role: Author
Kalpana L. Mani, MD, MEd
Neuroradiologist
Jefferson Radiology
Role: Author
Gul Moonis, MD
PHYSICIAN - NEURORADIOLOGY
NEW YORK PRESBYTERIAN HOSPITAL - COLUMBIA
Role: Author
Paul Schwartz, MD PhD
Director, Neurosurgical oncology and skull base surgery
Hartford Hospital
Role: Author
Belachew Tessema, MD
Assistant Clinical Professor
UCONN
Abstract Details
Purpose:
Pneumocephalus from an otogenic source is often caused by surgery, trauma, tumor, or infection, but can
also rarely be spontaneous, related to congenital skull base defects in the setting of pressure gradients across
the middle ear and intracranial compartment (via a ‘coke bottle’ effect in the setting of low intracranial pressure
versus a ‘ball valve’ phenomenon in the setting of high middle ear pressure). Spontaneous otogenic
pneumocephalus is generally visualized in the regional extra-axial CSF space, and intraparenchmal air has
also been infrequently reported.
Herein we describe a rare case of spontaneous otogenic pneumocephalus presenting initially with only
intraventricular air, a phenomenon that to our knowledge has been reported less than 5 times in the literature
dating back to 1884. Despite its rarity, this treatable etiology is useful for radiologists and referrers to be aware
of in the differential diagnosis of unexplained pneumocephalus. We review the symptoms, mechanisms,
imaging appearances, and treatment of spontaneous otogenic pneumocephalus.
Description:
A 57 year old woman presented with a two month history of worsening neurological symptoms including
headache and imbalance, as well as right ear fullness. Initial MR imaging performed for headache
demonstrated moderate, intraventricular air (Figure 1A) and a variant right temporal lobe cerebrospinal fluid
cleft extending from the extra-axial space adjacent to the inferior temporal gyrus to the ventricular margin of
the temporal horn, appearing contiguous with both. Follow up CT temporal bone demonstrated few areas of
tegmen tympani and tegmen mastoideum thinning/potential dehiscence without middle ear/mastoid
opacification (Figure 1B); CT sinus was negative without anterior skull base dehiscence or adjacent sinonasal
opacification. Additional history revealed no recent or remote sinonasal, otologic, intracranial or spinal
procedures; no history of skull base neoplastic or inflammatory processes, trauma, nor infectious symptoms.
There was, however, a long-standing history of eustachian tube dysfunction, exacerbated in recent months,
for which the patient routinely performed valsalva maneuvers.
The patient underwent both neurosurgical and ENT evaluation. The otological exam revealed intact tympanic
membranes and no middle ear effusion. An audiogram demonstrated mild, mixed low frequency hearing loss
of the right ear with negative pressure on tympanometry.
Follow up non-contrast head CT demonstrated tiny foci of air along the temporal lobe CSF cleft (Figure 1C).
Subsequent lateral skull base MRI with thin section heavily T2 weighted (CISS) coronal images demonstrated
a tiny inferiorly projecting cephalocele along the lateral tegmen mastoideum (Figure 1D); intraventricular air
had resolved (not shown). A pre-operative CTA demonstrated extra-axial air adjacent to the associated
tegmen defect (Figure 1E). The patient underwent temporal craniotomy at which time the defect of the tegmen
mastoideum and of the adjacent dura were identified and repaired (Figure 1F).
Summary:
Spontaneous otogenic pneumocephalus is a rare condition, resulting from congenital dehiscence of the
tegmen tympani or tegmen mastoideum in conjunction with pressure differentials across the defect, which
occasionally may present with intraventricular air. The skull base defect can be subtle and identification may
require multiple modalities or imaging performed at different time points. Surgical repair is the definitive
therapy.
(PE_10) MRI findings in infants with hearing loss and auditory neuropathy spectrum disorder due to
thiamine deficiency
Start Time: 2:25 PM
Author(s)
Anat Aizer-Dannon, MD
staff radiologist
Schneider Children's Medical Center
Role: Author
Renate Engisch, MD
staff radiologist
Institute of Diagnostic and Interventional Neuroradiology Bern University Hospital
Role: Author
Paul A. Caruso, MD
staff radiologist
Massachusetts Eye and Ear Infirmary, Harvard Medical School
Abstract Details
Purpose
Auditory neuropathy spectrum disorder (ANSD) is a cause of hearing loss thought to relate to a problem
in acoustic transmissions along the retrocochlear auditory pathway between the inner ear and the
auditory cortex. The key diagnostic features of hearing loss in ANSD are normal cochlear outer hair cell
function as reflected by normal otoacoustic emissions (OAEs) or normal cochlear microphonics (CMs)
but with abnormal auditory brainstem responses (ABRs).
A group of 11 Israeli children who developed encephalopathy due to nutritional thiamine deficiency has
previously been reported. These children later developed moderate to severe hearing loss with features
of ANSD and seven of these children underwent MR imaging as part of the diagnostic evaluation. The
purpose of the current study is to report the MR findings in these infants and to correlate them with the
clinical evaluation and outcome. To our knowledge this is the first report that describes the MR findings in
infants with auditory neuropathy spectrum disorder due to thiamine deficiency.
Methods
The clinical records were reviewed for demographics, age at presentation, duration of nutritional thiamine
deficiency, findings confirmatory of ANSD, outcome of the hearing loss following treatment with thiamine
supplementation, and for neurologic sequelae. The MRIs were reviewed for abnormal findings along the
auditory pathway from the external auditory canal to the cerebral cortex. All MRIs included T1 and T2
weighted images. Post gadolinium T1 weighted were available in six patients and DWI in five patients.
Four children underwent additional MR imaging following thiamine supplementation.
Results
The study group included 7 infants: five female and two male aged 3-10 months. The age at presentation
ranged from 3 to 10 months, and the estimated duration of feeding with the thiamine- deficient formula
ranged from 2 to 5 months. All 7 patients met criteria for ANSD with normal OAEs or CMs and abnormal
ABRs. Following thiamine supplementation, five patients improved and two had permanent ANSD. The
neurologic sequelae included seizures, ataxia, hemiparesis, and intellectual disability.
Along the auditory pathway, abnormal signal on the T2 weighted images was seen in the cochlear nuclei
in six patients, in the trapezoid body in four patients, in the lateral lemnisci in four patients, in the inferior
colliculi in five patients. Abnormal diminished diffusion was seen in the tectum, brainstem, posterior
thalami, and the basal ganglia. After the administration of thiamine, follow up MRI exams available in four
patients, showed improvement in the signal abnormality in the brain stem and tectum.
Conclusion:
Our report describes for the first time the MR findings along the auditory pathway in infants with auditory
neuropathy spectrum disorder due to nutritional thiamine deficiency.