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Robinson LJ, Goold E, Potter S, Quigley EP, Jensen RL, Mao Q. A pleomorphic xanthoastrocytoma highlighting the morphological heterogeneity of this uncommon tumor. J Neuropathol Exp Neurol 2023; 83:61-64. [PMID: 37950608 DOI: 10.1093/jnen/nlad097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023] Open
Affiliation(s)
| | - Eric Goold
- Department of Neuropathology, University of Utah, Salt Lake City, Utah, USA
| | - Scott Potter
- Department of Neuropathology, University of Utah, Salt Lake City, Utah, USA
| | - Edward P Quigley
- Department of Radiology, University of Utah, Salt Lake City, Utah, USA
| | - Randy L Jensen
- Department of Neurosurgery, University of Utah, Salt Lake City, Utah, USA
| | - Qinwen Mao
- Department of Neuropathology, University of Utah, Salt Lake City, Utah, USA
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Banerjee S, Pham T, Eastaway A, Auffermann WF, Quigley EP. The Use of Virtual Reality in Teaching Three-Dimensional Anatomy and Pathology on CT. J Digit Imaging 2023; 36:1279-1284. [PMID: 36717519 PMCID: PMC9886418 DOI: 10.1007/s10278-023-00784-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 02/01/2023] Open
Abstract
While radiological imaging is presented as two-dimensional images either on radiography or cross-sectional imaging, it is important for interpreters to understand three-dimensional anatomy and pathology. We hypothesized that virtual reality (VR) may serve as an engaging and effective way for trainees to learn to extrapolate from two-dimensional images to an understanding of these three-dimensional structures. We created a Google Cardboard Virtual Reality application that depicts intracranial vasculature and aneurysms. We then recruited 12 medical students to voluntarily participate in our study. The performance of the students in identifying intracranial aneurysms before and after the virtual reality training was evaluated and compared to a control group. While the experimental group's performance in correctly identifying aneurysms after virtual reality educational intervention was better than the control's (experimental increased by 5.3%, control decreased by 2.1%), the difference was not statistically significant (p-value of 0.06). Significantly, survey data from the medical students was very positive with students noting they preferred the immersive virtual reality training over conventional education and believed that VR would be a helpful educational tool for them in the future. We believe virtual reality can serve as an important tool to help radiology trainees better understand three-dimensional anatomy and pathology.
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Affiliation(s)
- Soham Banerjee
- Department of Radiology, Baylor College of Medicine, One Baylor Plaza BCM360, TX, Houston, USA.
| | - Theresa Pham
- Department of Radiology, University of Utah, Salt Lake City, UT, USA
| | - Adriene Eastaway
- Department of Radiology, University of Utah, Salt Lake City, UT, USA
| | | | - Edward P Quigley
- Department of Radiology, University of Utah, Salt Lake City, UT, USA
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Mai AP, Quigley EP, Harrie RP. Acute Unilateral Proptosis After Blunt Orbital Trauma in an Adolescent Patient. JAMA Ophthalmol 2023; 141:95-96. [PMID: 36394845 DOI: 10.1001/jamaophthalmol.2022.4748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A male patient aged 16 years with a recent history of blunt trauma to the periorbita presented with blurred vision, pain, and proptosis of the right eye. MRI imaging revealed an intraconal mass. What would you do next?
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Affiliation(s)
- Anthony P Mai
- John Moran Eye Center, University of Utah, Salt Lake City
| | | | - Roger P Harrie
- John Moran Eye Center, University of Utah, Salt Lake City
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4
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Bunch PM, Loevner LA, Bhala R, Hepp MB, Hirsch JA, Johnson MH, Lyp KL, Quigley EP, Salamon N, Jordan JE, Schwartz ES. The American Society of Neuroradiology: Cultivating a Diverse and Inclusive Culture to Build a Stronger Organization. AJNR Am J Neuroradiol 2021; 42:2127-2129. [PMID: 34593384 DOI: 10.3174/ajnr.a7310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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McNally JS, Hinckley PJ, Sakata A, Eisenmenger LB, Kim SE, De Havenon AH, Quigley EP, Iacob E, Treiman GS, Parker DL. Magnetic Resonance Imaging and Clinical Factors Associated With Ischemic Stroke in Patients Suspected of Cervical Artery Dissection. Stroke 2019; 49:2337-2344. [PMID: 30355108 DOI: 10.1161/strokeaha.118.021868] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose- Cervical artery dissection is a major cause of ischemic stroke in the young and presents with various imaging findings, including stenosis and intramural hematoma (IMH). Our goal was to determine the relative contribution of lumen findings and IMH to acute ischemic stroke and whether a heavily T1-weighted sequence could more reliably detect IMH. Methods- Institutional review board approval was obtained for this retrospective study of 254 patients undergoing magnetic resonance imaging/magnetic resonance angiography for suspected dissection. Imaging included standard turbo spin-echo (TSE) T1-fat saturation and heavily T1-weighted flow-suppressed magnetization-prepared rapid acquisition gradient-recalled echo sequences. Subjects with stents (1) or atherosclerotic disease (26) were excluded, leaving 227 subjects. Kappa analysis was used to determine IMH interrater reliability on magnetization-prepared rapid acquisition gradient-recalled echo and T1-fat saturation in 4 vessels per subject. Lumen findings, cardiovascular risk factors, medications, and nondissection stroke sources were recorded. Mixed-effects multivariate Poisson regression was used to determine the prevalence ratio of each factor with acute ischemic stroke, accounting for 4 vessels per patient with backward elimination to a threshold P value of 0.10. Results- Patients were 41.9% men, mean age of 47.3±16.6 years, with 114 dissections and 107 strokes. IMH interrater reliability was significantly higher for magnetization-prepared rapid acquisition gradient-recalled echo (κ=0.83; 95% CI, 0.78-0.86) versus T1-fat saturation (0.58; 95% CI, 0.57-0.68). The final acute stroke prediction model included magnetization-prepared rapid acquisition gradient-recalled echo-detected IMH (prevalence ratio, 2.0; 95% CI, 1.1-3.9; P=0.034), stenosis, pseudoaneurysm, male sex, current smoking, and nondissection stroke sources. The final model had high discrimination for acute stroke (area under the curve, 0.902; 95% CI, 0.872-0.932), compared with models without stenosis (0.861; 95% CI, 0.821-0.902), and without stenosis and IMH (0.831; 95% CI, 0.783-0.879). All 3 models were significantly different at P<0.05. Conclusions- Along with stenosis, IMH detection significantly contributed to acute ischemic stroke pathogenesis in patients with suspected cervical artery dissection. In addition, IMH detection can be made more reliable with heavily T1-weighted sequences.
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Affiliation(s)
- J Scott McNally
- From the Department of Radiology, Utah Center for Advanced Imaging Research (J.S.M., P.J.H., A.S., L.B.E., S.-E.K., E.P.Q., E.I., G.S.T., D.L.P.), University of Utah, Salt Lake City
| | - Peter J Hinckley
- From the Department of Radiology, Utah Center for Advanced Imaging Research (J.S.M., P.J.H., A.S., L.B.E., S.-E.K., E.P.Q., E.I., G.S.T., D.L.P.), University of Utah, Salt Lake City
| | - Akihiko Sakata
- From the Department of Radiology, Utah Center for Advanced Imaging Research (J.S.M., P.J.H., A.S., L.B.E., S.-E.K., E.P.Q., E.I., G.S.T., D.L.P.), University of Utah, Salt Lake City
| | - Laura B Eisenmenger
- From the Department of Radiology, Utah Center for Advanced Imaging Research (J.S.M., P.J.H., A.S., L.B.E., S.-E.K., E.P.Q., E.I., G.S.T., D.L.P.), University of Utah, Salt Lake City
| | - Seong-Eun Kim
- From the Department of Radiology, Utah Center for Advanced Imaging Research (J.S.M., P.J.H., A.S., L.B.E., S.-E.K., E.P.Q., E.I., G.S.T., D.L.P.), University of Utah, Salt Lake City
| | - Adam H De Havenon
- Department of Neurology (A.H.D.H.), University of Utah, Salt Lake City
| | - Edward P Quigley
- From the Department of Radiology, Utah Center for Advanced Imaging Research (J.S.M., P.J.H., A.S., L.B.E., S.-E.K., E.P.Q., E.I., G.S.T., D.L.P.), University of Utah, Salt Lake City
| | - Eli Iacob
- From the Department of Radiology, Utah Center for Advanced Imaging Research (J.S.M., P.J.H., A.S., L.B.E., S.-E.K., E.P.Q., E.I., G.S.T., D.L.P.), University of Utah, Salt Lake City
| | - Gerald S Treiman
- From the Department of Radiology, Utah Center for Advanced Imaging Research (J.S.M., P.J.H., A.S., L.B.E., S.-E.K., E.P.Q., E.I., G.S.T., D.L.P.), University of Utah, Salt Lake City.,Department of Surgery (G.S.T.), University of Utah, Salt Lake City.,Department of Surgery, VA Salt Lake City Health Care System, UT (G.S.T.)
| | - Dennis L Parker
- From the Department of Radiology, Utah Center for Advanced Imaging Research (J.S.M., P.J.H., A.S., L.B.E., S.-E.K., E.P.Q., E.I., G.S.T., D.L.P.), University of Utah, Salt Lake City
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Peckham ME, Shah LM, Tsai AC, Quigley EP, Cramer J, Hutchins TA. C1 Posterior Arch Flare Point: A Useful Landmark for Fluoroscopically Guided C1-2 Puncture. AJNR Am J Neuroradiol 2018; 39:1562-1567. [PMID: 29930095 DOI: 10.3174/ajnr.a5706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/04/2018] [Indexed: 12/30/2022]
Abstract
BACKGROUND AND PURPOSE The C1-2 intrathecal puncture is routinely performed when lumbar puncture is not feasible. Usage has steadily decreased in part because of the perceived high risk of injury to the cervical cord. Up to this point, vague fluoroscopic guidelines have been used, creating uncertainty about the actual needle location relative to the spinal cord. We present a novel osseous landmark to aid in C1-2 intrathecal puncture, corresponding to the posterior spinal cord margin on lateral fluoroscopic views. This landmark, which we have termed the "flare point," represents the triangular "flaring" of the posterior C1 arch at its junction with the anterior arch. MATERIALS AND METHODS Cervical spine CT myelograms were reviewed. High-resolution axial images were reformatted into the sagittal plane, and maximum-intensity-projection images were created to simulate a lateral fluoroscopic view. Tangential lines were drawn along the superior cortices of the anterior and posterior C1 arches, with the point of intersection used to approximate the flare point. Chart review was performed for all C1-2 punctures using the flare point technique in the past 3 years. RESULTS Forty-two cervical myelograms were reviewed. The average flare point was 0.2 ± 0.5 mm posterior to the dorsal spinal cord margin. In 37/42 subjects, the flare point was localized posterior to the spinal cord. Targeting by means of the flare point was used in 16 C1-2 punctures without complications. CONCLUSIONS The C1 posterior arch flare point accurately approximates the dorsal spinal cord margin on myelography. Targeting between the flare point and the spinolaminar line, at the mid-C1-2 interspace, allows safe and optimal needle positioning.
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Affiliation(s)
- M E Peckham
- From the Departments of Radiology and Imaging Sciences (M.E.P., L.M.S., A.T., E.P.Q., T.A.H.), University of Utah, Salt Lake City, Utah
| | - L M Shah
- From the Departments of Radiology and Imaging Sciences (M.E.P., L.M.S., A.T., E.P.Q., T.A.H.), University of Utah, Salt Lake City, Utah
| | - A C Tsai
- From the Departments of Radiology and Imaging Sciences (M.E.P., L.M.S., A.T., E.P.Q., T.A.H.), University of Utah, Salt Lake City, Utah
| | - E P Quigley
- From the Departments of Radiology and Imaging Sciences (M.E.P., L.M.S., A.T., E.P.Q., T.A.H.), University of Utah, Salt Lake City, Utah
| | - J Cramer
- Department of Radiology (J.C.), University of Nebraska Medical Center, Omaha, Nebraska
| | - T A Hutchins
- From the Departments of Radiology and Imaging Sciences (M.E.P., L.M.S., A.T., E.P.Q., T.A.H.), University of Utah, Salt Lake City, Utah
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Hwang ES, Bell JE, Quigley EP, Hoesch RE, Shakoor A. Stroke Due to Cerebral Vasculitis in a Patient with Relentless Placoid Chorioretinitis. Ocul Immunol Inflamm 2017; 26:921-923. [PMID: 28282738 DOI: 10.1080/09273948.2017.1279335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE To report the first case of stroke in a patient with relentless placoid chorioretinitis. METHODS Observational case report. RESULTS A 20-year-old female with newly diagnosed relentless placoid chorioretinitis was urgently evaluated for unilateral paresthesias. She was found to have acute bilateral pontine strokes and cerebral vasculitis on magnetic resonance imaging of the brain and cerebral angiography. CONCLUSIONS We report the first case of stroke due to cerebral vasculitis in a patient with relentless placoid chorioretinitis. This case emphasizes the need for timely evaluation of neurological symptoms in patients with this ocular diagnosis.
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Affiliation(s)
- Eileen S Hwang
- a John A. Moran Eye Center, Department of Ophthalmology , University of Utah , Salt Lake City , Utah , USA
| | - James E Bell
- a John A. Moran Eye Center, Department of Ophthalmology , University of Utah , Salt Lake City , Utah , USA
| | - Edward P Quigley
- b Department of Radiology , University of Utah , Salt Lake City , Utah , USA
| | - Robert E Hoesch
- c Neurosciences Institute, Intermountain Medical Center , Salt Lake City , Utah , USA
| | - Akbar Shakoor
- a John A. Moran Eye Center, Department of Ophthalmology , University of Utah , Salt Lake City , Utah , USA
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Juster-Switlyk K, Smith AG, Kovacsovics T, Stephens D, Glenn M, Palmer CA, Quigley EP, Kolb N. MTHFR C677T polymorphism is associated with methotrexate-induced myelopathy risk. Neurology 2017; 88:603-604. [PMID: 28062724 DOI: 10.1212/wnl.0000000000003590] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 10/25/2016] [Indexed: 11/15/2022] Open
Affiliation(s)
- Kelsey Juster-Switlyk
- From the University of Utah (K.J.-S., A.G.S., T.K., D.S., M.G., E.P.Q.); Huntsman Cancer Institute (C.A.P.), Salt Lake City, UT; and University of Vermont Medical Center (N.K.), Burlington
| | - A Gordon Smith
- From the University of Utah (K.J.-S., A.G.S., T.K., D.S., M.G., E.P.Q.); Huntsman Cancer Institute (C.A.P.), Salt Lake City, UT; and University of Vermont Medical Center (N.K.), Burlington
| | - Tibor Kovacsovics
- From the University of Utah (K.J.-S., A.G.S., T.K., D.S., M.G., E.P.Q.); Huntsman Cancer Institute (C.A.P.), Salt Lake City, UT; and University of Vermont Medical Center (N.K.), Burlington
| | - Deborah Stephens
- From the University of Utah (K.J.-S., A.G.S., T.K., D.S., M.G., E.P.Q.); Huntsman Cancer Institute (C.A.P.), Salt Lake City, UT; and University of Vermont Medical Center (N.K.), Burlington
| | - Martha Glenn
- From the University of Utah (K.J.-S., A.G.S., T.K., D.S., M.G., E.P.Q.); Huntsman Cancer Institute (C.A.P.), Salt Lake City, UT; and University of Vermont Medical Center (N.K.), Burlington
| | - Cheryl Ann Palmer
- From the University of Utah (K.J.-S., A.G.S., T.K., D.S., M.G., E.P.Q.); Huntsman Cancer Institute (C.A.P.), Salt Lake City, UT; and University of Vermont Medical Center (N.K.), Burlington
| | - Edward P Quigley
- From the University of Utah (K.J.-S., A.G.S., T.K., D.S., M.G., E.P.Q.); Huntsman Cancer Institute (C.A.P.), Salt Lake City, UT; and University of Vermont Medical Center (N.K.), Burlington
| | - Noah Kolb
- From the University of Utah (K.J.-S., A.G.S., T.K., D.S., M.G., E.P.Q.); Huntsman Cancer Institute (C.A.P.), Salt Lake City, UT; and University of Vermont Medical Center (N.K.), Burlington.
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9
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Koontz NA, Quigley EP, Witt BL, Sanders RK, Shah LM. Pigmented villonodular synovitis of the cervical spine: case report and review of the literature. BJR Case Rep 2015; 2:20150264. [PMID: 30364455 PMCID: PMC6195912 DOI: 10.1259/bjrcr.20150264] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 09/09/2015] [Accepted: 09/17/2015] [Indexed: 12/28/2022] Open
Abstract
Pigmented villonodular synovitis (PVNS) is an uncommon, benign, but locally aggressive lesion characterized most commonly by synovial proliferation of the appendicular large joints, but occasionally involving a bursa or the tendon sheath. PVNS of the spine is rare, typically involving the posterior elements. The lytic radiographic appearance and fludeoxyglucose avidity of PVNS may mimic malignant bone lesions, including metastatic disease or myeloma. On T1 and T2 weighted, and gradient recalled echo MRI sequences, the low signal intensity may mimic giant cell tumour of the bone, gout or synovial amyloid deposits, thus posing a diagnostic dilemma for the imagers and the treating clinicians. We present a pathologically confirmed case of PVNS of the cervical spine in a 49-year-old female, detailing her imaging work-up, describing histopathological correlation and highlighting the lesion location and involvement of the joint space as useful imaging discriminators for diagnosing PVNS of the cervical spine.
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Affiliation(s)
- Nicholas A Koontz
- Division of Neuroradiology, Department of Radiology, University of Utah Health Science Center, Salt Lake City, UT, USA
| | - Edward P Quigley
- Division of Neuroradiology, Department of Radiology, University of Utah Health Science Center, Salt Lake City, UT, USA
| | - Benjamin L Witt
- Division of Anatomic Pathology, Department of Pathology, University of Utah Health Science Center, Salt Lake City, UT, USA
| | - R Kent Sanders
- Division of Musculoskeletal Imaging, Department of Radiology, University of Utah Health Science Center, Salt Lake City, UT, USA
| | - Lubdha M Shah
- Division of Neuroradiology, Department of Radiology, University of Utah Health Science Center, Salt Lake City, UT, USA
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Abele TA, Besachio DA, Quigley EP, Gurgel RK, Shelton C, Harnsberger HR, Wiggins RH. Diagnostic accuracy of screening MR imaging using unenhanced axial CISS and coronal T2WI for detection of small internal auditory canal lesions. AJNR Am J Neuroradiol 2014; 35:2366-70. [PMID: 25034778 DOI: 10.3174/ajnr.a4041] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
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.
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Affiliation(s)
- T A Abele
- From the Departments of Radiology (T.A.A., E.P.Q., H.R.H., R.H.W.)
| | - D A Besachio
- Department of Radiology (D.A.B.), Naval Medical Center Portsmouth, Portsmouth, Virginia
| | - E P Quigley
- From the Departments of Radiology (T.A.A., E.P.Q., H.R.H., R.H.W.)
| | - R K Gurgel
- Division of Otolaryngology-Head and Neck Surgery (R.K.G., C.S., R.H.W.), University of Utah, Salt Lake City, Utah
| | - C Shelton
- Division of Otolaryngology-Head and Neck Surgery (R.K.G., C.S., R.H.W.), University of Utah, Salt Lake City, Utah
| | - H R Harnsberger
- From the Departments of Radiology (T.A.A., E.P.Q., H.R.H., R.H.W.)
| | - R H Wiggins
- From the Departments of Radiology (T.A.A., E.P.Q., H.R.H., R.H.W.) Biomedical Informatics (R.H.W.) Division of Otolaryngology-Head and Neck Surgery (R.K.G., C.S., R.H.W.), University of Utah, Salt Lake City, Utah
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Fanous AA, Quigley EP, Chin SS, Couldwell WT. Giant necrotic pituitary apoplexy. J Clin Neurosci 2013; 20:1462-4. [DOI: 10.1016/j.jocn.2012.07.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 07/11/2012] [Indexed: 10/26/2022]
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12
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Abstract
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.
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Affiliation(s)
- R P Nguyen
- Departments of Radiology, University of Utah Health Sciences Center, Salt Lake City, USA
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Lazzaro NA, Wright B, Castillo M, Fischbein NJ, Glastonbury CM, Hildenbrand PG, Wiggins RH, Quigley EP, Osborn AG. Artery of percheron infarction: imaging patterns and clinical spectrum. AJNR Am J Neuroradiol 2010; 31:1283-9. [PMID: 20299438 DOI: 10.3174/ajnr.a2044] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Occlusion of the AOP results in a characteristic pattern of ischemia: bilateral paramedian thalamus with or without midbrain involvement. Although the classic imaging findings are often recognized, only a few small case series and isolated cases of AOP infarction have been reported. The purpose of this study was to characterize the complete imaging spectrum of AOP infarction on the basis of a large series of cases obtained from multiple institutions. MATERIALS AND METHODS Imaging and clinical data of 37 patients with AOP infarction from 2000 to 2009 were reviewed retrospectively. The primary imaging criterion for inclusion was an abnormal signal intensity on MR imaging and/or hypoattenuation on CT involving distinct arterial zones of the bilateral paramedian thalami with or without rostral midbrain involvement. Patients were excluded if there was a neoplastic, infectious, or inflammatory etiology. RESULTS We identified 4 ischemic patterns of AOP infarction: 1) bilateral paramedian thalamic with midbrain (43%), 2) bilateral paramedian thalamic without midbrain (38%), 3) bilateral paramedian thalamic with anterior thalamus and midbrain (14%), and 4) bilateral paramedian thalamic with anterior thalamus without midbrain (5%). A previously unreported finding (the "V" sign) on FLAIR and DWI sequences was identified in 67% of cases of AOP infarction with midbrain involvement and supports the diagnosis when present. CONCLUSIONS The 4 distinct patterns of ischemia identified in our large case series, along with the midbrain V sign, should improve recognition of AOP infarction and assist with the neurologic evaluation and management of patients with thalamic strokes.
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Affiliation(s)
- Nicholas A Lazzaro
- Department of Radiology, University of Utah, Salt Lake City, Utah 84132-2140, USA.
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Armstrong KM, Quigley EP, Quigley P, Crumrine DS, Cukierman S. Covalently linked gramicidin channels: effects of linker hydrophobicity and alkaline metals on different stereoisomers. Biophys J 2001; 80:1810-8. [PMID: 11259294 PMCID: PMC1301370 DOI: 10.1016/s0006-3495(01)76151-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The direct role of the dioxolane group on the gating and single-channel conductance of different stereoisomers of the dioxolane-linked gramicidin A (gA) channels reconstituted in planar lipid bilayers was investigated. Four different covalently linked gA dimers were synthesized. In two of them, the linker was the conventional dioxolane described previously (SS and RR channels). Two gAs were covalently linked with a novel modified dioxolane group containing a retinal attachment (ret-SS and ret-RR gA dimers). These proteins also formed ion channels in lipid bilayers and were selective for monovalent cations. The presence of the bulky and hydrophobic retinal group immobilizes the dioxolane linker in the bilayer core preventing its rotation into the hydrophilic lumen of the pore. In 1 M HCl the gating kinetics of the SS or RR dimers were indistinguishable from their retinal counterparts; the dwell-time distributions of the open and closed states in the SS and ret-SS were basically the same. In particular, the inactivation of the RR was not prevented by the presence of the retinal group. It is concluded that neither the fast closing events in the SS or RR dimers nor the inactivation of the RR are likely to be a functional consequence of the flipping of the dioxolane inside the pore of the channel. On the other hand, the inactivation of the RR dimer was entirely eliminated when alkaline metals (Cs(+) or K(+)) were the permeating cations in the channel. In fact, the open state of the RR channel became extremely stable, and the gating characteristics of both the SS and RR channels were different from what was seen before with permeating protons. As in HCl, the presence of a retinal in the dioxolane linker did not affect the gating behavior of the SS and RR in Cs(+)- or K(+)-containing solutions. Alternative hypotheses concerning the gating of linked gA dimers are discussed.
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Affiliation(s)
- K M Armstrong
- Department of Physiology, Loyola University Medical School, Maywood, Illinois 60153, USA
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Quigley EP, Crumrine DS, Cukierman S. Gating and permeation in ion channels formed by gramicidin A and its dioxolane-linked dimer in Na(+) and Cs(+) solutions. J Membr Biol 2000; 174:207-12. [PMID: 10758174 DOI: 10.1007/s002320001045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The association of two gramicidin A (gA) peptides via H-bonds in lipid bilayers causes the formation of an ion channel that is selective for monovalent cations only. In this study, two gAs were covalently linked with a dioxolane group (SS dimer). Some functional properties of natural gA channels were compared to that synthetic dimer in Na(+)- or Cs(+)-containing solutions. The SS dimer remained in the open configuration most of the time, while natural gA channels had a relatively brief mean open time. Single channel conductances to Na(+) (g(Na)) or Cs(+) (g(Cs)) in the SS dimer were smaller than in natural gA. However, g(Na) was considerably more attenuated than g(Cs). This probably results from a tight solvation of Na(+) by the dioxolane linker in the SS channel. In Cs(+) solutions, the SS had frequent closures. By contrast, in Na(+) solutions the synthetic dimer remained essentially in the open state. The mean open times of SS channels in different solutions (T(open, Na) > T(open,Cs) > T(open,H)) were inversely proportional to the single channel conductances (g(H) > g(Cs) > g(Na)). This suggests that ion occupancy inside the pore stabilizes the open configuration of the gA dimer. The mean closed time of the SS dimer was longer in Cs(+) than in H(+) solutions. Possible mechanisms for these effects are discussed.
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Affiliation(s)
- E P Quigley
- Department of Physiology, Loyola School of Medicine, Maywood, IL 60153, USA
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Abstract
Two different stereoisomers of the dioxolane-linked gramicidin A (gA) channels were individually synthesized (the SS and RR dimers;. Science. 244:813-817). The structural differences between these dimers arise from different chiralities within the dioxolane linker. The SS dimer mimics the helicity and the inter- and intramolecular hydrogen bonding of the monomer-monomer association of gA's. In contrast, there is a significant disruption of the helicity and hydrogen bonding pattern of the ion channel in the RR dimer. Single ion channels formed by the SS and RR dimers in planar lipid bilayers have different proton transport properties. The lipid environment in which the different dimers are reconstituted also has significant effects on single-channel proton conductance (g(H)). g(H) in the SS dimer is about 2-4 times as large as in the RR. In phospholipid bilayers with 1 M [H(+)](bulk), the current-voltage (I-V) relationship of the SS dimer is sublinear. Under identical experimental conditions, the I-V plot of the RR dimer is supralinear (S-shaped). In glycerylmonooleate bilayers with 1 M [H(+)](bulk), both the SS and RR dimers have a supralinear I-V plot. Consistent with results previously published (. Biophys. J. 73:2489-2502), the SS dimer is stable in lipid bilayers and has fast closures. In contrast, the open state of the RR channel has closed states that can last a few seconds, and the channel eventually inactivates into a closed state in either phospholipid or glycerylmonooleate bilayers. It is concluded that the water dynamics inside the pore as related to proton wire transfer is significantly different in the RR and SS dimers. Different physical mechanisms that could account for this hypothesis are discussed. The gating of the synthetic gA dimers seems to depend on the conformation of the dioxolane link between gA's. The experimental results provide an important framework for a detailed investigation at the atomic level of proton conduction in different and relatively simple ion channel structures.
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Affiliation(s)
- E P Quigley
- Department of Physiology, Loyola University Medical Center, Maywood, Illinois 60153, USA
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Quigley EP, Emerick AJ, Crumrine DS, Cukierman S. Attenuation of proton currents by methanol in a dioxolane-linked gramicidin A channel in different lipid bilayers. Biophys J 1998; 75:2811-20. [PMID: 9826603 PMCID: PMC1299954 DOI: 10.1016/s0006-3495(98)77724-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mobility of protons in a dioxolane-linked gramicidin A channel (D1) is comparable to the mobility of protons in aqueous solutions (Cukierman, S., E. P. Quigley, and D. S. Crumrine. 1997. Biophys. J. 73:2489-2502). Aliphatic alcohols decrease the mobility of H+ in aqueous solutions. In this study, the effects of methanol on proton conduction through D1 channels were investigated in different lipid bilayers and at different HCl concentrations. Methanol attenuated H+ currents in a voltage-independent manner. Attenuation of proton currents was also independent of H+ concentrations in solution. In phospholipid bilayers, methanol decreased the single channel conductance to protons without affecting the binding affinity of protons to bilayers. In glycerylmonooleate membranes, the attenuation of single channel proton conductances qualitatively resembled the decrease of conductivities of HCl solutions by methanol. However, in both types of lipid bilayers, single channel proton conductances through D1 channels were considerably more attenuated than the conductivities of different HCl solutions. This suggests that methanol modulates single proton currents through D1 channels. It is proposed that, on average, one methanol molecule binds to a D1 channel, and attenuates H+ conductance. The Gibbs free energy of this process (DeltaG0) is approximately 1.2 kcal/mol, which is comparable to the free energy of decrease of HCl conductivity in methanol solutions (1.6 kcal/mol). Apolar substances like urea and glucose that do not transport protons in HCl solutions and do not permeate D1 channels decreased solution conductivity and single channel conductance by a considerably larger proportion than methanol. Cs+ currents through D1 channels were considerably less (fivefold) attenuated by methanol than proton currents. It is proposed that methanol partitions inside the pore of gramicidin channels and delays the transfer of protons between water and methanol molecules, causing a significant attenuation of the single channel proton conductance. Gramicidin channels offer an interesting experimental model to study proton hopping along a single chain of water molecules interrupted by a single methanol molecule.
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Affiliation(s)
- E P Quigley
- Department of Physiology, Loyola University Medical Center, Maywood, Illinois 60153 USA
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Abstract
Gramicidin A (gA) molecules were covalently linked with a dioxolane ring. Dioxolane-linked gA dimers formed ion channels, selective for monovalent cations, in planar lipid bilayers. The main goal of this study was to compare the functional single ion channel properties of natural gA and its covalently linked dimer in two different lipid bilayers and HCl concentrations (10-8000 mM). Two ion channels with different gating and conductance properties were identified in bilayers from the product of dimerization reaction. The most commonly observed and most stable gramicidin A dimer is the main object of this study. This gramicidin dimer remained in the open state most of the time, with brief closing flickers (tau(closed) approximately 30 micros). The frequency of closing flickers increased with transmembrane potential, making the mean open time moderately voltage dependent (tau(open) changed approximately 1.43-fold/100 mV). Such gating behavior is markedly different from what is seen in natural gA channels. In PEPC (phosphatidylethanolamine-phosphatidylcholine) bilayers, single-channel current-voltage relationships had an ohmic behavior at low voltages, and a marked sublinearity at relatively higher voltages. This behavior contrasts with what was previously described in GMO (glycerylmonooleate) bilayers. In PEPC bilayers, the linear conductance of single-channel proton currents at different proton concentrations was essentially the same for both natural and gA dimers. g(max) and K(D), obtained from fitting experimental points to a Langmuir adsorption isotherm, were approximately 1500 pS and 300 mM, respectively, for both the natural gA and its dimer. In GMO bilayers, however, proton affinities of gA and the dioxolane-dimer were significantly lower (K(D) of approximately 1 and 1.5 M, respectively), and the g(max) higher (approximately 1750 and 2150 pS, respectively) than in PEPC bilayers. Furthermore, the relationship between single-channel conductance and proton concentration was linear at low bulk concentrations of H+ (0.01-2 M) and saturated at concentrations of more than 3 M. It is concluded that 1) The mobility of protons in gramicidin A channels in different lipid bilayers is remarkably similar to proton mobilities in aqueous solutions. In particular, at high concentrations of HCl, proton mobilities in gramicidin A channel and in solution differ by only 25%. 2) Differences between proton conductances in gramicidin A channels in GMO and PEPC cannot be explained by surface charge effects on PEPC membranes. It is proposed that protonated phospholipids adjacent to the mouth of the pore act as an additional source of protons for conduction through gA channels in relation to GMO bilayers. 3) Some experimental results cannot be reconciled with simple alterations in access resistance to proton flow in gA channels. Said differences could be explained if the structure and/or dynamics of water molecules inside gramicidin A channels is modulated by the lipid environment and by modifications in the structure of gA channels. 4) The dioxolane ring is probably responsible for the closing flickers seen in the dimer channel. However, other factors can also influence closing flickers.
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Affiliation(s)
- S Cukierman
- Department of Physiology, Loyola University Medical Center, Maywood, Illinois 60153, USA
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