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Klaassen L, Haasjes C, Hol M, Cambraia Lopes P, Spruijt K, van de Steeg-Henzen C, Vu K, Bakker P, Rasch C, Verbist B, Beenakker JW. Geometrical accuracy of magnetic resonance imaging for ocular proton therapy planning. Phys Imaging Radiat Oncol 2024; 31:100598. [PMID: 38993288 PMCID: PMC11234150 DOI: 10.1016/j.phro.2024.100598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 05/31/2024] [Accepted: 06/05/2024] [Indexed: 07/13/2024] Open
Abstract
Background & purpose Magnetic resonance imaging (MRI) is increasingly used in treatment preparation of ocular proton therapy, but its spatial accuracy might be limited by geometric distortions due to susceptibility artefacts. A correct geometry of the MR images is paramount since it defines where the dose will be delivered. In this study, we assessed the geometrical accuracy of ocular MRI. Materials & methods A dedicated ocular 3 T MRI protocol, with localized shimming and increased gradients, was compared to computed tomography (CT) and X-ray images in a phantom and in 15 uveal melanoma patients. The MRI protocol contained three-dimensional T2-weighted and T1-weighted sequences with an isotropic reconstruction resolution of 0.3-0.4 mm. Tantalum clips were identified by three observers and clip-clip distances were compared between T2-weighted and T1-weighted MRI, CT and X-ray images for the phantom and between MRI and X-ray images for the patients. Results Interobserver variability was below 0.35 mm for the phantom and 0.30(T1)/0.61(T2) mm in patients. Mean absolute differences between MRI and reference were below 0.27 ± 0.16 mm and 0.32 ± 0.23 mm for the phantom and in patients, respectively. In patients, clip-clip distances were slightly larger on MRI than on X-ray images (mean difference T1: 0.11 ± 0.38 mm, T2: 0.10 ± 0.44 mm). Differences did not increase at larger distances and did not correlate to interobserver variability. Conclusions A dedicated ocular MRI protocol can produce images of the eye with a geometrical accuracy below half the MRI acquisition voxel (<0.4 mm). Therefore, these images can be used for ocular proton therapy planning, both in the current model-based workflow and in proposed three-dimensional MR-based workflows.
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Affiliation(s)
- Lisa Klaassen
- Leiden University Medical Center, Department of Ophthalmology, Leiden, the Netherlands
- Leiden University Medical Center, Department of Radiology, Leiden, the Netherlands
- Leiden University Medical Center, Department of Radiation Oncology, Leiden, the Netherlands
| | - Corné Haasjes
- Leiden University Medical Center, Department of Ophthalmology, Leiden, the Netherlands
- Leiden University Medical Center, Department of Radiology, Leiden, the Netherlands
- Leiden University Medical Center, Department of Radiation Oncology, Leiden, the Netherlands
| | - Martijn Hol
- Leiden University Medical Center, Department of Radiation Oncology, Leiden, the Netherlands
- HollandPTC, Delft, the Netherlands
| | | | | | - Christal van de Steeg-Henzen
- Leiden University Medical Center, Department of Radiology, Leiden, the Netherlands
- HollandPTC, Delft, the Netherlands
| | - Khanh Vu
- Leiden University Medical Center, Department of Ophthalmology, Leiden, the Netherlands
| | - Pauline Bakker
- Leiden University Medical Center, Department of Radiation Oncology, Leiden, the Netherlands
- HollandPTC, Delft, the Netherlands
| | - Coen Rasch
- Leiden University Medical Center, Department of Radiation Oncology, Leiden, the Netherlands
- HollandPTC, Delft, the Netherlands
| | - Berit Verbist
- Leiden University Medical Center, Department of Radiology, Leiden, the Netherlands
- HollandPTC, Delft, the Netherlands
| | - Jan-Willem Beenakker
- Leiden University Medical Center, Department of Ophthalmology, Leiden, the Netherlands
- Leiden University Medical Center, Department of Radiology, Leiden, the Netherlands
- Leiden University Medical Center, Department of Radiation Oncology, Leiden, the Netherlands
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Simpson ARH, Hughes EH, Mullen L, Dowell NG. In vivo measurement of T 1 in the vitreous humor of patients with ischemic retinal disease. Magn Reson Med 2024; 91:381-387. [PMID: 37800364 DOI: 10.1002/mrm.29849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 08/14/2023] [Accepted: 08/14/2023] [Indexed: 10/07/2023]
Abstract
PURPOSE To demonstrate MR T1 mapping in vivo as a method to non-invasively estimate vitreous oxygen concentration in ischemic eye disease. METHODS Patients with ischemic eye disease (central retinal vein occlusion, ocular ischemic syndrome, and proliferative diabetic retinopathy) were prospectively recruited. MRI was performed on each patient before any treatment, with T1 mapping acquired using an inversion recovery TrueFISP sequence at several inversion times, from a single slice positioned through the center of both eyes in the axial oblique plane. A phantom study measuring seven different concentrations of vitronectin, a protein released in ischemic eye disease, was undertaken to determine its potential confounding effect on T1 . RESULTS Ten participants were recruited (eight central retinal vein occlusion, one ocular ischemic syndrome, and one proliferative diabetic retinopathy). Of the eight central retinal vein occlusion cases, there was a statistically different vitreous T1 in the diseased eye compared to the healthy control eye (4.306 vs. 4.518 s, p = 0.008). T1 times did not significantly alter across the range of vitronectin concentrations. CONCLUSIONS Ischemic eye disease decreases vitreous T1 , potentially implying an increase in vitreous partial pressure of oxygen (pO2 ) concentration given what is known from the relationship between 1/T1 and pO2 . Potential theories for this unexpected result are discussed. This study provides further data on this technique, with potential clinical application in eye disease.
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Affiliation(s)
| | | | - Lisa Mullen
- Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, Brighton, UK
| | - Nicholas G Dowell
- Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, Brighton, UK
- Centre for Regenerative Medicine and Devices, School of Pharmacy, and Bimolecular Sciences, University of Brighton, Brighton, UK
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Baker JHE, Moosvi F, Kyle AH, Püspöky Banáth J, Saatchi K, Häfeli UO, Reinsberg SA, Minchinton AI. Radiosensitizing oxygenation changes in murine tumors treated with VEGF-ablation therapy are measurable using oxygen enhanced-MRI (OE-MRI). Radiother Oncol 2023; 187:109795. [PMID: 37414252 DOI: 10.1016/j.radonc.2023.109795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/15/2023] [Accepted: 06/30/2023] [Indexed: 07/08/2023]
Abstract
PURPOSE There is a significant need for a widely available, translatable, sensitive and non-invasive imaging biomarker for tumor hypoxia in radiation oncology. Treatment-induced changes in tumor tissue oxygenation can alter the sensitivity of cancer tissues to radiation, but the relative difficulty in monitoring the tumor microenvironment results in scarce clinical and research data. Oxygen-Enhanced MRI (OE-MRI) uses inhaled oxygen as a contrast agent to measure tissue oxygenation. Here we investigate the utility of dOE-MRI, a previously validated imaging approach employing a cycling gas challenge and independent component analysis (ICA), to detect VEGF-ablation treatment-induced changes in tumor oxygenation that result in radiosensitization. METHODS Murine squamous cell carcinoma (SCCVII) tumor-bearing mice were treated with 5 mg/kg anti-VEGF murine antibody B20 (B20-4.1.1, Genentech) 2-7 days prior to radiation treatment, tissue collection or MR imaging using a 7 T scanner. dOE-MRI scans were acquired for a total of three repeated cycles of air (2 min) and 100% oxygen (2 min) with responding voxels indicating tissue oxygenation. DCE-MRI scans were acquired using a high molecular weight (MW) contrast agent (Gd-DOTA based hyperbranched polygylcerol; HPG-GdF, 500 kDa) to obtain fractional plasma volume (fPV) and apparent permeability-surface area product (aPS) parameters derived from the MR concentration-time curves. Changes to the tumor microenvironment were evaluated histologically, with cryosections stained and imaged for hypoxia, DNA damage, vasculature and perfusion. Radiosensitizing effects of B20-mediated increases in oxygenation were evaluated by clonogenic survival assays and by staining for DNA damage marker γH2AX. RESULTS Tumors from mice treated with B20 exhibit changes to their vasculature that are consistent with a vascular normalization response, and result in a temporary period of reduced hypoxia. DCE-MRI using injectable contrast agent HPG-GDF measured decreased vessel permeability in treated tumors, while dOE-MRI using inhaled oxygen as a contrast agent showed greater tissue oxygenation. These treatment-induced changes to the tumor microenvironment result in significantly increased radiation sensitivity, illustrating the utility of dOE-MRI as a non-invasive biomarker of treatment response and tumor sensitivity during cancer interventions. CONCLUSIONS VEGF-ablation therapy-mediated changes to tumor vascular function measurable using DCE-MRI techniques may be monitored using the less invasive approach of dOE-MRI, an effective biomarker of tissue oxygenation that can monitor treatment response and predict radiation sensitivity.
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Affiliation(s)
| | - Firas Moosvi
- University of British Columbia, Department of Physics & Astronomy, Vancouver, BC, V6T 1Z1, Canada
| | - Alastair Hugh Kyle
- Integrative Oncology - Radiation Biology Unit, BC Cancer Research Institute, Vancouver, BC, V5Z 1L3, Canada
| | - Judit Püspöky Banáth
- Integrative Oncology - Radiation Biology Unit, BC Cancer Research Institute, Vancouver, BC, V5Z 1L3, Canada
| | - Katayoun Saatchi
- University of British Columbia, Faculty of Pharmaceutical Sciences, Vancouver, BC, V6T 1Z3, Canada
| | - Urs Otto Häfeli
- University of British Columbia, Faculty of Pharmaceutical Sciences, Vancouver, BC, V6T 1Z3, Canada
| | | | - Andrew Ivor Minchinton
- Integrative Oncology - Radiation Biology Unit, BC Cancer Research Institute, Vancouver, BC, V5Z 1L3, Canada
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Jaarsma-Coes MG, Klaassen L, Marinkovic M, Luyten GPM, Vu THK, Ferreira TA, Beenakker JWM. Magnetic Resonance Imaging in the Clinical Care for Uveal Melanoma Patients-A Systematic Review from an Ophthalmic Perspective. Cancers (Basel) 2023; 15:cancers15112995. [PMID: 37296958 DOI: 10.3390/cancers15112995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/24/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
Conversely to most tumour types, magnetic resonance imaging (MRI) was rarely used for eye tumours. As recent technical advances have increased ocular MRI's diagnostic value, various clinical applications have been proposed. This systematic review provides an overview of the current status of MRI in the clinical care of uveal melanoma (UM) patients, the most common eye tumour in adults. In total, 158 articles were included. Two- and three-dimensional anatomical scans and functional scans, which assess the tumour micro-biology, can be obtained in routine clinical setting. The radiological characteristics of the most common intra-ocular masses have been described extensively, enabling MRI to contribute to diagnoses. Additionally, MRI's ability to non-invasively probe the tissue's biological properties enables early detection of therapy response and potentially differentiates between high- and low-risk UM. MRI-based tumour dimensions are generally in agreement with conventional ultrasound (median absolute difference 0.5 mm), but MRI is considered more accurate in a subgroup of anteriorly located tumours. Although multiple studies propose that MRI's 3D tumour visualisation can improve therapy planning, an evaluation of its clinical benefit is lacking. In conclusion, MRI is a complementary imaging modality for UM of which the clinical benefit has been shown by multiple studies.
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Affiliation(s)
- Myriam G Jaarsma-Coes
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
- Department of Radiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Lisa Klaassen
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
- Department of Radiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
- Department of Radiation Oncology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Marina Marinkovic
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Gregorius P M Luyten
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - T H Khanh Vu
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Teresa A Ferreira
- Department of Radiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Jan-Willem M Beenakker
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
- Department of Radiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
- Department of Radiation Oncology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
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5
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Jaarsma-Coes MG, Klaassen L, Verbist BM, Vu TK, Klaver YL, Rodrigues MF, Nabarro C, Luyten GP, Rasch CR, van Herk M, Beenakker JWM. Inter-Observer Variability in MR-Based Target Volume Delineation of Uveal Melanoma. Adv Radiat Oncol 2022; 8:101149. [PMID: 36691449 PMCID: PMC9860418 DOI: 10.1016/j.adro.2022.101149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 12/14/2022] [Indexed: 12/26/2022] Open
Abstract
Purpose Several efforts are being undertaken toward MRI-based treatment planning for ocular proton therapy for uveal melanoma (UM). The interobserver variability of the gross target volume (GTV) on magnetic resonance imaging (MRI) is one of the important parameters to design safety margins for a reliable treatment. Therefore, this study assessed the interobserver variation in GTV delineation of UM on MRI. Methods and Materials Six observers delineated the GTV in 10 different patients using the Big Brother contouring software. Patients were scanned at 3T MRI with a surface coil, and tumors were delineated separately on contrast enhanced 3DT1 (T1gd) and 3DT2-weighted scans with an isotropic acquisition resolution of 0.8 mm. Volume difference and overall local variation (median standard deviation of the distance between the delineated contours and the median contour) were analyzed for each GTV. Additionally, the local variation was analyzed for 4 interfaces: sclera, vitreous, retinal detachment, and tumor-choroid interface. Results The average GTV was significantly larger on T1gd (0.57cm3) compared with T2 (0.51cm3, P = .01). A not significant higher interobserver variation was found on T1gd (0.41 mm) compared with T2 (0.35 mm). The largest variations were found at the tumor-choroid interface due to peritumoral enhancement (T1gd, 0.62 mm; T2, 0.52 mm). As a result, a larger part of this tumor-choroid interface appeared to be included on T1gd-based GTVs compared with T2, explaining the smaller volumes on T2. Conclusions The interobserver variation of 0.4 mm on MRI are low with respect to the voxel size of 0.8 mm, enabling small treatment margins. We recommend delineation based on the T1gd-weighted scans, as choroidal tumor extensions might be missed.
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Affiliation(s)
- Myriam G. Jaarsma-Coes
- Leiden University Medical Center, Ophthalmology, Leiden, Netherlands,Leiden University Medical Center, Radiology, Leiden, Netherlands
| | - Lisa Klaassen
- Leiden University Medical Center, Ophthalmology, Leiden, Netherlands,Leiden University Medical Center, Radiology, Leiden, Netherlands
| | - Berit M. Verbist
- Leiden University Medical Center, Radiology, Leiden, Netherlands
| | - T.H. Khanh Vu
- Leiden University Medical Center, Ophthalmology, Leiden, Netherlands
| | - Yvonne L.B. Klaver
- HollandPTC, Radiation oncology, Delft, Netherlands,Leiden University Medical Center, Radiation Oncology, Leiden, Netherlands
| | - Myra F. Rodrigues
- HollandPTC, Radiation oncology, Delft, Netherlands,Leiden University Medical Center, Radiation Oncology, Leiden, Netherlands
| | - Claire Nabarro
- Leiden University Medical Center, Radiology, Leiden, Netherlands
| | | | - Coen R.N. Rasch
- HollandPTC, Radiation oncology, Delft, Netherlands,Leiden University Medical Center, Radiation Oncology, Leiden, Netherlands
| | - Marcel van Herk
- Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom
| | - Jan-Willem M. Beenakker
- Leiden University Medical Center, Ophthalmology, Leiden, Netherlands,Leiden University Medical Center, Radiology, Leiden, Netherlands,Leiden University Medical Center, Radiation Oncology, Leiden, Netherlands,Corresponding author: Jan-Willem M. Beenakker
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6
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Beenakker JWM, Rasch CRN. Letter to the Editor of Radiotherapy and Oncology regarding the paper titled "MRI and FUNDUS image fusion for improved ocular biometry in Ocular Proton Therapy" by Via et al. Radiother Oncol 2022; 176:251. [PMID: 35988772 DOI: 10.1016/j.radonc.2022.08.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 08/15/2022] [Indexed: 12/14/2022]
Affiliation(s)
- Jan-Willem M Beenakker
- Department of Radiation Oncology, Leiden University Medical Center, 2333ZA Leiden, The Netherlands; Department of Radiology, Leiden University Medical Center, 2333ZA Leiden, The Netherlands; Department of Ophthalmology, Leiden University Medical Center, 2333ZA Leiden, The Netherlands.
| | - Coen R N Rasch
- Department of Radiation Oncology, Leiden University Medical Center, 2333ZA Leiden, The Netherlands
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7
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Zeng Y, Nguyen VP, Li Y, Kang DH, Paulus YM, Kim J. Chorioretinal Hypoxia Detection Using Lipid-Polymer Hybrid Organic Room-Temperature Phosphorescent Nanoparticles. ACS APPLIED MATERIALS & INTERFACES 2022; 14:18182-18193. [PMID: 35420786 PMCID: PMC9780709 DOI: 10.1021/acsami.2c02767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Ischemia-induced hypoxia is a common complication associated with numerous diseases and is the most important prognostic factor in retinal vein occlusions (RVOs). Early detection and long-term visualization of retinal tissue hypoxia is essential to understand the pathophysiology and treatment of ischemic retinopathies. However, no effective solution exists to evaluate extravascular retinal tissue oxygen tension. Here, we demonstrate a lipid-polymer hybrid organic room-temperature phosphorescence (RTP) nanoparticle (NP) platform that optically detects tissue hypoxia in real-time with high signal-to-noise ratio. The fabricated NPs exhibit long-lived bright RTP, high sensitivity toward oxygen quenching, and desirable colloidal and optical stability. When tested as a hypoxia imaging probe in vivo using rabbit RVO and choroidal vascular occlusion (CVO) models via intravitreal and intravenous (IV) injections, respectively, its RTP signal is exclusively turned on where tissue hypoxia is present with a signal-to-noise ratio of 12.5. The RTP NP platform is compatible with multimodal imaging. No ocular or systemic complications are observed with either administration route. The developed organic RTP NPs present a novel platform approach that allows for biocompatible, nondestructive detection of tissue hypoxia and holds promise as a sensitive imaging tool to monitor longitudinal tissue oxygen levels and evaluate various hypoxia-driven vascular diseases.
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Affiliation(s)
- Yingying Zeng
- Macromolecular Science and Engineering, University of Michigan 2800 Plymouth Road, Ann Arbor, MI 48109, USA
- Biointerfaces Institute, University of Michigan 2800 Plymouth Road, Ann Arbor, MI 48105, USA
| | - Van Phuc Nguyen
- Department of Ophthalmology and Visual Sciences Kellogg Eye Center, University of Michigan 1000 Wall Street, Ann Arbor, MI 48105, USA
- NTT-Hi Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh, Vietnam
| | - Yanxiu Li
- Department of Ophthalmology and Visual Sciences Kellogg Eye Center, University of Michigan 1000 Wall Street, Ann Arbor, MI 48105, USA
| | - Do Hyun Kang
- Biointerfaces Institute, University of Michigan 2800 Plymouth Road, Ann Arbor, MI 48105, USA
- Department of Materials Science and Engineering, University of Michigan 2300 Hayward St, Ann Arbor, MI 48109, USA
| | - Yannis M. Paulus
- Department of Ophthalmology and Visual Sciences Kellogg Eye Center, University of Michigan 1000 Wall Street, Ann Arbor, MI 48105, USA
- Department of Biomedical Engineering, University of Michigan 2200 Bonisteel Blvd, Ann Arbor, MI 48109, USA
| | - Jinsang Kim
- Macromolecular Science and Engineering, University of Michigan 2800 Plymouth Road, Ann Arbor, MI 48109, USA
- Biointerfaces Institute, University of Michigan 2800 Plymouth Road, Ann Arbor, MI 48105, USA
- Department of Materials Science and Engineering, University of Michigan 2300 Hayward St, Ann Arbor, MI 48109, USA
- Department of Biomedical Engineering, University of Michigan 2200 Bonisteel Blvd, Ann Arbor, MI 48109, USA
- Department of Chemistry, University of Michigan 930 N. University Ave, Ann Arbor, MI 48109, USA
- Department of Chemical Engineering, University of Michigan 2300 Hayward St, Ann Arbor, MI 48109, USA
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Eye-specific quantitative dynamic contrast-enhanced MRI analysis for patients with intraocular masses. MAGMA (NEW YORK, N.Y.) 2022; 35:311-323. [PMID: 34643852 PMCID: PMC8995252 DOI: 10.1007/s10334-021-00961-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/30/2021] [Accepted: 09/20/2021] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Dynamic contrast enhanced (DCE)-MRI is currently not generally used for intraocular masses as lesions are small, have an inhomogeneous T1 and the eye is prone to motion. The aim of this paper is to address these eye-specific challenges, enabling accurate ocular DCE-MRI. MATERIALS & METHODS DCE-MRI of 19 uveal melanoma (UM) patients was acquired using a fat-suppressed 3D spoiled gradient echo sequence with TWIST (time-resolved angiography with stochastic trajectories sequence). The analysis consisted of a two-step registration method to correct for both head and eye motion. A T1 map was calculated to convert signal intensities to concentrations. Subsequently, the Tofts model was fitted voxel wise to obtain Ktrans and ve. RESULTS Registration significantly improved the concentration curve quality (p < 0.001). The T1 of melanotic lesions was significantly lower than amelanotic lesions (888 ms vs 1350 ms, p = 0.03). The average achieved B1+ in the lesions was 91%. The average Ktrans was 0.46 min-1 (range 0.13-1.0) and the average ve was 0.22 (range 0.10-0.51). CONCLUSION Using this eye-specific analysis, DCE of intraocular masses is possible which might aid in the diagnosis, prognosis and follow-up of UM.
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van Vught L, Shamonin DP, Luyten GPM, Stoel BC, Beenakker JWM. MRI-based 3D retinal shape determination. BMJ Open Ophthalmol 2021; 6:e000855. [PMID: 34901465 PMCID: PMC8611437 DOI: 10.1136/bmjophth-2021-000855] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 10/30/2021] [Indexed: 01/15/2023] Open
Abstract
Objective To establish a good method to determine the retinal shape from MRI using three-dimensional (3D) ellipsoids as well as evaluate its reproducibility. Methods and analysis The left eyes of 31 volunteers were imaged using high-resolution ocular MRI. The 3D MR-images were segmented and ellipsoids were fitted to the resulting contours. The dependency of the resulting ellipsoid parameters on the evaluated fraction of the retinal contour was assessed by fitting ellipsoids to 41 different fractions. Furthermore, the reproducibility of the complete procedure was evaluated in four subjects. Finally, a comparison with conventional two-dimensional (2D) methods was made. Results The mean distance between the fitted ellipsoids and the segmented retinal contour was 0.03±0.01 mm (mean±SD) for the central retina and 0.13±0.03 mm for the peripheral retina. For the central retina, the resulting ellipsoid radii were 12.9±0.9, 13.7±1.5 and 12.2±1.2 mm along the horizontal, vertical and central axes. For the peripheral retina, these radii decreased to 11.9±0.6, 11.6±0.4 and 10.4±0.7 mm, which was accompanied by a mean 1.8 mm posterior shift of the ellipsoid centre. The reproducibility of the ellipsoid fitting was 0.3±1.2 mm for the central retina and 0.0±0.1 mm for the peripheral retina. When 2D methods were used to fit the peripheral retina, the fitted radii differed a mean 0.1±0.1 mm from the 3D method. Conclusion An accurate and reproducible determination of the 3D retinal shape based on MRI is provided together with 2D alternatives, enabling wider use of this method in the field of ophthalmology.
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Affiliation(s)
- Luc van Vught
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Radiology, CJ Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
| | - Denis P Shamonin
- Department of Radiology, Division of Image Processing (LKEB), Leiden University Medical Center, Leiden, The Netherlands
| | - Gregorius P M Luyten
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands
| | - Berend C Stoel
- Department of Radiology, Division of Image Processing (LKEB), Leiden University Medical Center, Leiden, The Netherlands
| | - Jan-Willem M Beenakker
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Radiology, CJ Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
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10
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van Vught L, Dekker CE, Stoel BC, Luyten GPM, Beenakker JWM. Evaluation of intraocular lens position and retinal shape in negative dysphotopsia using high-resolution magnetic resonance imaging. J Cataract Refract Surg 2021; 47:1032-1038. [PMID: 33577270 DOI: 10.1097/j.jcrs.0000000000000576] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/26/2020] [Indexed: 02/03/2023]
Abstract
PURPOSE To assess potential relationships of intraocular lens (IOL) position and retinal shape in negative dysphotopsia (ND). SETTING Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands. DESIGN Case-control study. METHODS High-resolution ocular magnetic resonance imaging (MRI) scans were performed in patients with ND and pseudophakic controls, and subsequently used to determine the displacement and tilt of the in-the-bag IOL about the pupil and iris. In addition, anterior segment tomography was used to assess the iris-IOL distance. Furthermore, the retinal shape was quantified from the MRI scans by fitting an ellipse to the segmented inner boundary of the retina. Both the IOL position and retinal shape were compared between groups to assess their potential role in the etiology of ND. RESULTS In total, 37 patients with ND and 26 pseudophakic controls were included in the study. The mean displacement and tilt of the IOL were less than 0.1 mm and 0.5 degrees, respectively, in both groups and all directions. The corresponding mean iris-IOL distance was 1.1 mm in both groups. Neither of these values differed statistically significantly between groups (all P values >.6). The retinal shape showed large variations but was not statistically significantly different between the groups in both the left-right (P = .10) and the anterior-posterior (P = .56) directions. CONCLUSIONS In this study, the in-the-bag IOL position and retinal shape did not statistically significantly differ between patients with ND and the general pseudophakic population. Given the large variation in retinal shape between subjects, however, it could still be an important factor in a multifactorial origin of ND.
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Affiliation(s)
- Luc van Vught
- From the Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands (van Vught, Luyten, Beenakker); Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, the Netherlands (van Vught, Beenakker); Division of Image Processing (LKEB), Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands (Dekker, Stoel)
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Deng F, Reinshagen KL, Li MD, Juliano AF. Motion degradation in optic nerve MRI: A randomized intraindividual comparison study of eye states. Eur J Radiol 2021; 142:109865. [PMID: 34298389 DOI: 10.1016/j.ejrad.2021.109865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 02/02/2023]
Abstract
PURPOSE MRI is a powerful tool for optic nerve assessment, but image quality can be degraded by artifacts related to ocular motion. The purpose of this investigation was to evaluate the effect of undergoing MRI with eyes open versus closed on the degree of motion degradation affecting the optic nerves. METHOD Patients undergoing 3 Tesla orbital MRI were randomized to undergo the coronal STIR sequence with eyes open and focused on a standardized fixation point, blinking as needed, or with eyes closed. The sequence was then performed again with the other instruction set. Two neuroradiologists rated the intraorbital optic nerves for motion artifact on a 5-point scale (higher numbers reflecting greater motion artifact) in 2 locations of each nerve. Differences were evaluated by the clustered Wilcoxon signed rank test. RESULTS Seventy-seven orbits were included. Interrater reliability was high (weighted kappa = 0.78). The anterior intraorbital optic nerves were rated with less motion artifact when eyes were open and focused during acquisition than when closed (p = 0.006), but this was not the case for the posterior intraorbital optic nerve (p = 0.69). For example, at the anterior intraorbital optic nerve, motion artifact of mean grade better than 2 was seen in 60% of eyes-open vs. 32% of eyes-closed acquisitions, while mean grade 4 or worse was seen in 4% of eyes-open vs. 12% of eyes-closed acquisitions. CONCLUSION Undergoing orbital MRI with eyes open and focused rather than closed reduces motion artifact at the anterior intraorbital segment of the optic nerve.
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Affiliation(s)
- Francis Deng
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
| | - Katherine L Reinshagen
- Department of Radiology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA.
| | - Matthew D Li
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
| | - Amy F Juliano
- Department of Radiology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA.
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12
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Shughoury A, Mathew S, Arciero J, Wurster P, Adjei S, Ciulla T, Siesky B, Harris A. Retinal oximetry in glaucoma: investigations and findings reviewed. Acta Ophthalmol 2020; 98:559-571. [PMID: 32248646 DOI: 10.1111/aos.14397] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 02/20/2020] [Indexed: 12/17/2022]
Abstract
Abnormalities of the retinal blood supply have been widely implicated in primary open-angle glaucoma (POAG). Impaired blood supply to the retina and optic nerve head (ONH) may be a primary pathophysiologic mechanism contributing to POAG ('vascular hypothesis'). However, the decreased metabolic activity of atrophic tissue is itself known to induce both vascular changes and decreased blood flow due to reduced oxygen demand. Therefore, primary nonvascular factors could potentially induce glaucomatous atrophy, with subsequent secondary vascular pathology ('mechanical hypothesis'). Retinal oximetry holds great promise in the investigation of glaucoma pathogenesis, as it can provide useful data on retinal metabolic oxygen demand, especially when combined with measurements of retinal blood flow. This review surveys the research on retinal metabolism in POAG using spectroscopic retinal oximetry. The use of mathematical models in combination with oximetric data to investigate the role of retinal metabolism and oxygen supply in POAG is also discussed.
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Affiliation(s)
- Aumer Shughoury
- Eugene and Marilyn Glick Eye Institute Department of Ophthalmology Indiana University School of Medicine Indianapolis IN USA
| | - Sunu Mathew
- Eugene and Marilyn Glick Eye Institute Department of Ophthalmology Indiana University School of Medicine Indianapolis IN USA
| | - Julia Arciero
- Department of Mathematical Sciences Indiana University Purdue University Indianapolis IN USA
| | - Patrick Wurster
- Eugene and Marilyn Glick Eye Institute Department of Ophthalmology Indiana University School of Medicine Indianapolis IN USA
| | - Susuana Adjei
- Eugene and Marilyn Glick Eye Institute Department of Ophthalmology Indiana University School of Medicine Indianapolis IN USA
| | | | - Brent Siesky
- Icahn School of Medicine at Mount Sinai New York NY USA
| | - Alon Harris
- Icahn School of Medicine at Mount Sinai New York NY USA
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13
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Abstract
Supplemental Digital Content is available in the text. Uveal melanoma (UM), the most common primary intraocular tumour, is often complicated by exudative retinal detachment (RD). Sometimes, this exudative RD is mistaken for a rhegmatogenous detachment and is subsequently treated with vitrectomy with silicone oil (SiOil) tamponade. As SiOil prevents ultrasound imaging, the diagnosis, treatment planning and/or follow-up of UM underlying the detachment are often severely hindered by the SiOil. We aim to develop and evaluate new MRI methods to image UM patients with a SiOil tamponade and evaluate this in vivo. A dedicated MRI protocol for 3 and 7 T was developed and subsequently evaluated in three patients. The MRI protocol developed was evaluated in three patients. In the first patient, SiOil hindered follow-up and therefore MRI was indicated. No tumour recurrence was found after two follow-up scans. The second and third patient underwent vitrectomy with SiOil for assumed rhegmatogenous RD in another hospital, during which a mass was found. In these cases, MRI was used to determine whether the lesion was UM and perform measurements to plan brachytherapy treatment. In general, the proposed workflow is more complicated on 7 T than on 3 T as the off-resonance effects scale linearly with field strength. For example, the shimming procedure needed modifications at 7 T, whereas at 3 T, the automatic shimming sufficed. However, at 7 T, higher resolution images were obtained compared with 3 T (0.6 vs. 0.8 mm3). A dedicated MRI protocol enables high-resolution imaging of vitrectomized eyes with SiOil tamponade, enabling treatment planning or follow-up in UM patients.
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14
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Grech Fonk L, Ferreira TA, Webb AG, Luyten GPM, Beenakker JWM. The Economic Value of MR-Imaging for Uveal Melanoma. Clin Ophthalmol 2020; 14:1135-1143. [PMID: 32425499 PMCID: PMC7196205 DOI: 10.2147/opth.s238405] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 03/03/2020] [Indexed: 12/12/2022] Open
Abstract
Objective Uveal melanoma (UM) is the most common primary intra-ocular tumour. Treatment is determined by tumour size and location. Generally, smaller tumours are eligible for brachytherapy unless they are located close to posterior pole. Larger tumours are enucleated or undergo proton beam therapy (PBT), which is more expensive than brachytherapy and less available. Accuracy of tumour size determination is critical for accurate planning and delivery of treatment, particularly to ensure tumour coverage, critical structure sparing, and for the choice of treatment modality. This is particularly the case for tumour dimensions that are close to the cut-off point for a specific type of treatment: in the case of the brachytherapy protocol at our institution, 6-8 mm. Ultrasound is conventionally used, but magnetic resonance imaging (MRI) has recently become an additional available tool. Although more expensive, it enables more accurate measurements and is particularly useful in combination with clinical fundus examination, fundus photography and ultrasound. Our aim in this paper was to determine the economic value of MRI for UM treatment. Methods We retrospectively analysed 60 patients' MRI scans acquired as part of a study or for clinical care. For each patient, we assessed whether the extra cost of an MRI generated economic benefit or change in optimal treatment. Results MRI indicated a smaller tumour prominence than US in 10% of patients with intermediate tumour size, resulting in a change from PBT to brachytherapy. The costs of MRI, €200-€1000, are significantly lower than the higher costs of PBT compared to brachytherapy, €24,000 difference. In addition, the annual total economic burden of severe vision impairment associated with eye removal is €10,000. Furthermore, for patients where ultrasound was impossible due to previous surgery, MRI enabled eye-preserving treatment. Conclusion An additional MRI for specific patients with UM improves economic value as it enables less expensive treatment in a sufficient percentage of patients to compensate for the MRI costs. Value is increased in terms of quality of care as it enables for some a treatment option which spares more vision.
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Affiliation(s)
- Lorna Grech Fonk
- Department of Ophthalmology, Leiden University Medical Centre, Leiden, the Netherlands.,Department of Radiology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Teresa A Ferreira
- Department of Radiology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Andrew G Webb
- Department of Radiology, Leiden University Medical Centre, Leiden, the Netherlands.,C.J. Gorter Centre for High Field Magnetic Resonance Imaging, Department of Radiology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Gregorius P M Luyten
- Department of Ophthalmology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Jan-Willem M Beenakker
- Department of Ophthalmology, Leiden University Medical Centre, Leiden, the Netherlands.,Department of Radiology, Leiden University Medical Centre, Leiden, the Netherlands
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15
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Toward noninvasive quantification of adipose tissue oxygenation with MRI. Int J Obes (Lond) 2020; 44:1776-1783. [PMID: 32231252 DOI: 10.1038/s41366-020-0567-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 02/27/2020] [Accepted: 03/04/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND Molecular oxygen (O2) plays a key role in normal and pathological adipose tissue function, yet technologies to measure its role in adipose tissue function are limited. O2 is paramagnetic and, in principle, directly influences the magnetic resonance (MR) 1H longitudinal relaxation rate constant of lipids, R1; thus, we hypothesize that MR imaging (MRI) can directly measure adipose O2 via a simple measure of R1. METHODS R1 was measured in a 4.7T preclinical MRI system at discrete oxygen partial pressure (pO2) levels. These measures were made in vitro in an idealized system and in vivo in subcutaneous and visceral white adipose of rodents. pO2 was determined using an invasive fiber-optic oxygen monitor. From the MRI and fiber optic data we determined the "relaxivity" of O2 in lipid, a critical parameter in converting the MRI-based R1 measurement into pO2. We used breathing gas challenge to estimate the changes in lipid pO2 (ΔpO2). RESULTS The relaxivity of O2 in lipid was determined to be 1.7·10-3 ± 4·10-4 mmHg-1s-1 at 4.7T and 37 °C, and was consistent between in vitro and in vivo adipose tissue. There was a strong, significant correlation between MRI- and gold standard OxyLite-based measurements of lipid ΔpO2 for in vivo visceral and subcutaneous fat depots in rodents. CONCLUSION This study lays the foundation for a direct, noninvasive measure of adipose pO2 using MRI and will allow for noninvasive measurement of O2 flux in adipose tissue. The proposed approach would be of particular importance in the interrogation of the pathogenesis of type 2 diabetes, where it has been suggested that adipose tissue hypoxia is an independent driver of insulin resistance pathway.
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16
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Beenakker JWM, Wezel J, Groen J, Webb AG, Börnert P. Silent volumetric multi-contrast 7 Tesla MRI of ocular tumors using Zero Echo Time imaging. PLoS One 2019; 14:e0222573. [PMID: 31525248 PMCID: PMC6746372 DOI: 10.1371/journal.pone.0222573] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 09/03/2019] [Indexed: 02/03/2023] Open
Abstract
Magnetic Resonance Imaging (MRI) has become a valuable imaging modality in ophthalmology, especially for the diagnosis and treatment planning of patients with uveal melanoma, the most common primary intra-ocular tumor. We aim to develop and evaluate the value of silent Zero Echo Time (ZTE) MRI to image patients with ocular tumors at 7Tesla. Therefore, ZTE and different types of magnetization-prepared ZTE (FLAIR, SPIR, T2 and Saturation recovery), have been developed. After an initial validation with 7 healthy subjects, nine patients with an eye tumor have been evaluated. The ZTE scans were compared to their Cartesian equivalent in terms of contrast, motion-sensitivity, diagnostic quality and patient comfort. All volunteers and especially the patients reported a more comfortable experience during the ZTE scans, which had at least a 10 dB lower sound pressure. The image contrast in the native ZTE was poor, but in the different magnetization-prepared ZTE, the eye lens, cornea and retina were clearly discriminated. Overall the T2-prepared scan yielded the best contrast, especially between tumor and healthy tissue, and proved to be robust against eye motion. Although the intrinsic 3D nature of the ZTE-technique provides an accurate analysis of the tumor morphology, the quality of the ZTE-images is lower than their Cartesian equivalent. In conclusion, the quality of magnetization-prepared ZTE images is sufficient to assess the 3D tumor morphology, but insufficient for more detailed evaluations. As such this technique can be an option for patients who cannot comply with the sound-levels of Cartesian scans, but for other patients the conventional Cartesian scans offer a better image quality.
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Affiliation(s)
- Jan-Willem M. Beenakker
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
- Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands
| | - Joep Wezel
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Jan Groen
- Philips Healthcare, Best, the Netherlands
| | - Andrew G. Webb
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Peter Börnert
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
- Philips Research Laboratories, Hamburg, Germany
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17
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Yang DM, Arai TJ, Campbell JW, Gerberich JL, Zhou H, Mason RP. Oxygen-sensitive MRI assessment of tumor response to hypoxic gas breathing challenge. NMR IN BIOMEDICINE 2019; 32:e4101. [PMID: 31062902 PMCID: PMC6581571 DOI: 10.1002/nbm.4101] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 02/16/2019] [Accepted: 03/08/2019] [Indexed: 06/09/2023]
Abstract
Oxygen-sensitive MRI has been extensively used to investigate tumor oxygenation based on the response (R2 * and/or R1 ) to a gas breathing challenge. Most studies have reported response to hyperoxic gas indicating potential biomarkers of hypoxia. Few studies have examined hypoxic gas breathing and we have now evaluated acute dynamic changes in rat breast tumors. Rats bearing syngeneic subcutaneous (n = 15) or orthotopic (n = 7) 13762NF breast tumors were exposed to a 16% O2 gas breathing challenge and monitored using blood oxygen level dependent (BOLD) R2 * and tissue oxygen level dependent (TOLD) T1 -weighted measurements at 4.7 T. As a control, we used a traditional hyperoxic gas breathing challenge with 100% O2 on a subset of the subcutaneous tumor bearing rats (n = 6). Tumor subregions identified as responsive on the basis of R2 * dynamics coincided with the viable tumor area as judged by subsequent H&E staining. As expected, R2 * decreased and T1 -weighted signal increased in response to 100% O2 breathing challenge. Meanwhile, 16% O2 breathing elicited an increase in R2 *, but divergent response (increase or decrease) in T1 -weighted signal. The T1 -weighted signal increase may signify a dominating BOLD effect triggered by 16% O2 in the relatively more hypoxic tumors, whereby the influence of increased paramagnetic deoxyhemoglobin outweighs decreased pO2 . The results emphasize the importance of combined BOLD and TOLD measurements for the correct interpretation of tumor oxygenation properties.
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Affiliation(s)
- Donghan M Yang
- Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Tatsuya J Arai
- Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - James W Campbell
- Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, USA
| | | | - Heling Zhou
- Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Ralph P Mason
- Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, USA
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18
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Koolstra K, Beenakker JM, Koken P, Webb A, Börnert P. Cartesian MR fingerprinting in the eye at 7T using compressed sensing and matrix completion-based reconstructions. Magn Reson Med 2019; 81:2551-2565. [PMID: 30421448 PMCID: PMC6519255 DOI: 10.1002/mrm.27594] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 10/09/2018] [Accepted: 10/12/2018] [Indexed: 12/14/2022]
Abstract
PURPOSE To explore the feasibility of MR Fingerprinting (MRF) to rapidly quantify relaxation times in the human eye at 7T, and to provide a data acquisition and processing framework for future tissue characterization in eye tumor patients. METHODS In this single-element receive coil MRF approach with Cartesian sampling, undersampling is used to shorten scan time and, therefore, to reduce the degree of motion artifacts. For reconstruction, approaches based on compressed sensing (CS) and matrix completion (MC) were used, while their effects on the quality of the MRF parameter maps were studied in simulations and experiments. Average relaxation times in the eye were measured in 6 healthy volunteers. One uveal melanoma patient was included to show the feasibility of MRF in a clinical context. RESULTS Simulation results showed that an MC-based reconstruction enables large undersampling factors and also results in more accurate parameter maps compared with using CS. Experiments in 6 healthy volunteers used a reduction in scan time from 7:02 to 1:16 min, producing images without visible loss of detail in the parameter maps when using the MC-based reconstruction. Relaxation times from 6 healthy volunteers are in agreement with values obtained from fully sampled scans and values in literature, and parameter maps in a uveal melanoma patient show clear difference in relaxation times between tumor and healthy tissue. CONCLUSION Cartesian-based MRF is feasible in the eye at 7T. High undersampling factors can be achieved by means of MC, significantly shortening scan time and increasing patient comfort, while also mitigating the risk of motion artifacts.
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Affiliation(s)
- Kirsten Koolstra
- RadiologyC.J. Gorter Center for High‐Field MRI, Leiden University Medical CenterLeidenThe Netherlands
| | - Jan‐Willem Maria Beenakker
- RadiologyC.J. Gorter Center for High‐Field MRI, Leiden University Medical CenterLeidenThe Netherlands
- OphthalmologyLeiden University Medical CenterLeidenThe Netherlands
| | | | - Andrew Webb
- RadiologyC.J. Gorter Center for High‐Field MRI, Leiden University Medical CenterLeidenThe Netherlands
| | - Peter Börnert
- RadiologyC.J. Gorter Center for High‐Field MRI, Leiden University Medical CenterLeidenThe Netherlands
- Philips ResearchHamburgGermany
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19
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Ferreira TA, Grech Fonk L, Jaarsma-Coes MG, van Haren GGR, Marinkovic M, Beenakker JWM. MRI of Uveal Melanoma. Cancers (Basel) 2019; 11:cancers11030377. [PMID: 30884881 PMCID: PMC6468484 DOI: 10.3390/cancers11030377] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/08/2019] [Accepted: 03/12/2019] [Indexed: 12/24/2022] Open
Abstract
Uveal Melanoma (UM) is the most common primary malignant ocular tumor. The high soft tissue contrast and spatial resolution, and the possibility of generating 3D volumetric and functional images, make Magnetic Resonance Imaging (MRI) a valuable diagnostic imaging technique in UM. Current clinical MRI protocols, however, are not optimized for UM and therefore lack the quality for accurate assessments. We therefore developed a dedicated protocol at a 3 Tesla MRI, using an eye coil, consisting of multi-slice 2D sequences, different isotropic sequences and diffusion and perfusion-weighted images. This protocol was prospectively evaluated in 9 uveal melanoma patients. The multi-slice 2D sequences had the highest in-plane resolution, being the most suited for lesion characterization and local extension evaluation. The isotropic 3D Turbo-Spin Echo (TSE) sequences were the most suitable for accurate geometric measurements of the tumor and are therefore important for therapy planning. Diffusion and perfusion-weighted images aid in differentiating benign from malignant lesions and provide quantitative measures on tumor hemodynamics and cellularity, which have been reported to be effective in predicting and assessing treatment outcome. Overall, this dedicated MRI protocol provides high-quality imaging of UM, which can be used to improve its diagnosis, treatment planning, and follow-up.
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Affiliation(s)
- Teresa A Ferreira
- Department of Radiology, Leiden University Medical Centre, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
| | - Lorna Grech Fonk
- Department of Radiology, Leiden University Medical Centre, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
- Department of Ophthalmology, Leiden University Medical Centre, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
| | - Myriam G Jaarsma-Coes
- Department of Radiology, Leiden University Medical Centre, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
- Department of Ophthalmology, Leiden University Medical Centre, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
| | - Guido G R van Haren
- Department of Radiology, Leiden University Medical Centre, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
| | - Marina Marinkovic
- Department of Ophthalmology, Leiden University Medical Centre, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
| | - Jan-Willem M Beenakker
- Department of Radiology, Leiden University Medical Centre, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
- Department of Ophthalmology, Leiden University Medical Centre, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
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20
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Moosvi F, Baker JH, Yung A, Kozlowski P, Minchinton AI, Reinsberg SA. Fast and sensitive dynamic oxygen‐enhanced MRI with a cycling gas challenge and independent component analysis. Magn Reson Med 2018; 81:2514-2525. [DOI: 10.1002/mrm.27584] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/04/2018] [Accepted: 10/07/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Firas Moosvi
- Department of Physics & Astronomy University of British Columbia Vancouver Canada
| | - Jennifer H.E. Baker
- Radiation Biology Unit British Columbia Cancer Research Centre Vancouver Canada
| | - Andrew Yung
- UBC MRI Research Centre Life Sciences Centre Vancouver Canada
| | - Piotr Kozlowski
- UBC MRI Research Centre Life Sciences Centre Vancouver Canada
- Department of Radiology University of British Columbia Vancouver Canada
| | | | - Stefan A. Reinsberg
- Department of Physics & Astronomy University of British Columbia Vancouver Canada
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21
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Neupane R, Gaudana R, Boddu SHS. Imaging Techniques in the Diagnosis and Management of Ocular Tumors: Prospects and Challenges. AAPS JOURNAL 2018; 20:97. [PMID: 30187172 DOI: 10.1208/s12248-018-0259-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 08/23/2018] [Indexed: 12/23/2022]
Abstract
Different types of imaging modalities are used in the diagnosis of ocular cancer. Selection of an imaging modality is based on the features of a tumor as well as the inherent characteristics of the imaging technique. It is vital to select an appropriate imaging modality in diagnosis of ocular tumor with confidence. This review focuses on five most commonly used imaging modalities, i.e., positron emission tomography-computed tomography (PET/CT), single photon emission computed tomography (SPECT), optical coherence tomography (OCT), ultrasound (US), and magnetic resonance imaging (MRI). The principal of imaging modalities is briefly explained, along with their role in the diagnosis and management of the most common ocular tumors such as retinoblastoma and uveal melanoma. Further, the diagnostic features of ocular tumors corresponding to each imaging modality and possibilities of utilizing imaging techniques in the process of ocular drug development are included in this review.
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Affiliation(s)
- Rabin Neupane
- College of Pharmacy and Pharmaceutical Sciences, The University of Toledo Health Science Campus, Toledo, OH, 43614, USA
| | - Ripal Gaudana
- Principal Scientist, Par Pharmaceuticals, 1 Ram Ridge Rd, Spring Valley, New York, 10977, USA
| | - Sai H S Boddu
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Ajman University, P.O. Box 346, Ajman, United Arab Emirates.
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22
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Zhou H, Arias-Ramos N, López-Larrubia P, Mason RP, Cerdán S, Pacheco-Torres J. Oxygenation Imaging by Nuclear Magnetic Resonance Methods. Methods Mol Biol 2018; 1718:297-313. [PMID: 29341016 DOI: 10.1007/978-1-4939-7531-0_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Oxygen monitoring is a topic of exhaustive research due to its central role in many biological processes, from energy metabolism to gene regulation. The ability to monitor in vivo the physiological distribution and the dynamics of oxygen from subcellular to macroscopic levels is a prerequisite to better understand the mechanisms associated with both normal and disease states (cancer, neurodegeneration, stroke, etc.). This chapter focuses on magnetic resonance imaging (MRI) based techniques to assess oxygenation in vivo. The first methodology uses injected fluorinated agents to provide quantitative pO2 measurements with high precision and suitable spatial and temporal resolution for many applications. The second method exploits changes in endogenous contrasts, i.e., deoxyhemoglobin and oxygen molecules through measurements of T 2* and T 1, in response to an intervention to qualitatively evaluate hypoxia and its potential modulation.
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Affiliation(s)
- Heling Zhou
- Prognostic Imaging Research Laboratory, Department of Radiology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Nuria Arias-Ramos
- Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Biociències, Edifici Cs, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
| | - Pilar López-Larrubia
- Instituto de Investigaciones Biomédicas 'Alberto Sols' C.S.I.C./U.A.M., Madrid, Spain
| | - Ralph P Mason
- Prognostic Imaging Research Laboratory, Department of Radiology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Sebastián Cerdán
- Instituto de Investigaciones Biomédicas 'Alberto Sols' C.S.I.C./U.A.M., Madrid, Spain
| | - Jesús Pacheco-Torres
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, San Juan de Alicante, Alicante, Spain.
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23
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Sengupta S, Smith DS, Smith AK, Welch EB, Smith SA. Dynamic Imaging of the Eye, Optic Nerve, and Extraocular Muscles With Golden Angle Radial MRI. Invest Ophthalmol Vis Sci 2017; 58:4390–4398. [PMID: 28813574 PMCID: PMC5559179 DOI: 10.1167/iovs.17-21861] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purpose The eye and its accessory structures, the optic nerve and the extraocular muscles, form a complex dynamic system. In vivo magnetic resonance imaging (MRI) of this system in motion can have substantial benefits in understanding oculomotor functioning in health and disease, but has been restricted to date to imaging of static gazes only. The purpose of this work was to develop a technique to image the eye and its accessory visual structures in motion. Methods Dynamic imaging of the eye was developed on a 3-Tesla MRI scanner, based on a golden angle radial sequence that allows freely selectable frame-rate and temporal-span image reconstructions from the same acquired data set. Retrospective image reconstructions at a chosen frame rate of 57 ms per image yielded high-quality in vivo movies of various eye motion tasks performed in the scanner. Motion analysis was performed for a left-right version task where motion paths, lengths, and strains/globe angle of the medial and lateral extraocular muscles and the optic nerves were estimated. Results Offline image reconstructions resulted in dynamic images of bilateral visual structures of healthy adults in only ∼15-s imaging time. Qualitative and quantitative analyses of the motion enabled estimation of trajectories, lengths, and strains on the optic nerves and extraocular muscles at very high frame rates of ∼18 frames/s. Conclusions This work presents an MRI technique that enables high-frame-rate dynamic imaging of the eyes and orbital structures. The presented sequence has the potential to be used in furthering the understanding of oculomotor mechanics in vivo, both in health and disease.
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Affiliation(s)
- Saikat Sengupta
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - David S Smith
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Alex K Smith
- The Centre for Functional MRI of the Brain, The University of Oxford, Oxford, United Kingdom
| | - E Brian Welch
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States
| | - Seth A Smith
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States
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Chen S, Shu X, Nesper PL, Liu W, Fawzi AA, Zhang HF. Retinal oximetry in humans using visible-light optical coherence tomography [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:1415-1429. [PMID: 28663838 PMCID: PMC5480553 DOI: 10.1364/boe.8.001415] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 02/01/2017] [Accepted: 02/01/2017] [Indexed: 05/18/2023]
Abstract
We measured hemoglobin oxygen saturation (sO2) in the retinal circulation in healthy humans using visible-light optical coherence tomography (vis-OCT). The measurements showed clear oxygenation differences between central retinal arteries and veins close to the optic nerve head. Spatial variations at different vascular branching levels were also revealed. In addition, we presented theoretical and experimental results to establish that noises in OCT intensity followed Rice distribution. We used this knowledge to retrieve unbiased estimation of true OCT intensity to improve the accuracy of vis-OCT oximetry, which had inherently lower signal-to-nose ratio from human eyes due to safety and comfort limitations. We demonstrated that the new statistical-fitting sampling strategy could reduce the estimation error in sO2 by three percentage points (pp). The presented work aims to provide a foundation for using vis-OCT to achieve accurate retinal oximetry in clinical settings.
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Affiliation(s)
- Siyu Chen
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Xiao Shu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Peter L. Nesper
- Department of Ophthalmology, Northwestern University, Chicago, IL 60611, USA
| | - Wenzhong Liu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Currently with Opticent Health, Evanston, IL 60208, USA
| | - Amani A. Fawzi
- Department of Ophthalmology, Northwestern University, Chicago, IL 60611, USA
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Ophthalmology, Northwestern University, Chicago, IL 60611, USA
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25
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Linsenmeier RA, Zhang HF. Retinal oxygen: from animals to humans. Prog Retin Eye Res 2017; 58:115-151. [PMID: 28109737 DOI: 10.1016/j.preteyeres.2017.01.003] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 01/13/2017] [Accepted: 01/17/2017] [Indexed: 10/20/2022]
Abstract
This article discusses retinal oxygenation and retinal metabolism by focusing on measurements made with two of the principal methods used to study O2 in the retina: measurements of PO2 with oxygen-sensitive microelectrodes in vivo in animals with a retinal circulation similar to that of humans, and oximetry, which can be used non-invasively in both animals and humans to measure O2 concentration in retinal vessels. Microelectrodes uniquely have high spatial resolution, allowing the mapping of PO2 in detail, and when combined with mathematical models of diffusion and consumption, they provide information about retinal metabolism. Mathematical models, grounded in experiments, can also be used to simulate situations that are not amenable to experimental study. New methods of oximetry, particularly photoacoustic ophthalmoscopy and visible light optical coherence tomography, provide depth-resolved methods that can separate signals from blood vessels and surrounding tissues, and can be combined with blood flow measures to determine metabolic rate. We discuss the effects on retinal oxygenation of illumination, hypoxia and hyperoxia, and describe retinal oxygenation in diabetes, retinal detachment, arterial occlusion, and macular degeneration. We explain how the metabolic measurements obtained from microelectrodes and imaging are different, and how they need to be brought together in the future. Finally, we argue for revisiting the clinical use of hyperoxia in ophthalmology, particularly in retinal arterial occlusions and retinal detachment, based on animal research and diffusion theory.
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Affiliation(s)
- Robert A Linsenmeier
- Biomedical Engineering Department, Northwestern University, 2145 Sheridan Road, Evanston 60208-3107, IL, USA; Neurobiology Department, Northwestern University, 2205 Tech Drive, Evanston 60208-3520, IL, USA; Ophthalmology Department, Northwestern University, 645 N. Michigan Ave, Suite 440, Chicago 60611, IL, USA.
| | - Hao F Zhang
- Biomedical Engineering Department, Northwestern University, 2145 Sheridan Road, Evanston 60208-3107, IL, USA; Ophthalmology Department, Northwestern University, 645 N. Michigan Ave, Suite 440, Chicago 60611, IL, USA.
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26
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Wezel J, Garpebring A, Webb AG, van Osch MJ, Beenakker JWM. Automated eye blink detection and correction method for clinical MR eye imaging. Magn Reson Med 2016; 78:165-171. [DOI: 10.1002/mrm.26355] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/14/2016] [Accepted: 07/05/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Joep Wezel
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center; Leiden The Netherlands
| | - Anders Garpebring
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center; Leiden The Netherlands
- Radiation Sciences; Umeå University; Umeå Sweden
| | - Andrew G. Webb
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center; Leiden The Netherlands
| | - Matthias J.P. van Osch
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center; Leiden The Netherlands
| | - Jan-Willem M. Beenakker
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center; Leiden The Netherlands
- Department of Ophthalmology; Leiden University Medical Center; Leiden The Netherlands
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Berkowitz BA, Lewin AS, Biswal MR, Bredell BX, Davis C, Roberts R. MRI of Retinal Free Radical Production With Laminar Resolution In Vivo. Invest Ophthalmol Vis Sci 2016; 57:577-85. [PMID: 26886890 PMCID: PMC4771178 DOI: 10.1167/iovs.15-18972] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Recent studies have suggested the hypothesis that quench-assisted 1/T1 magnetic resonance imaging (MRI) measures free radical production with laminar resolution in vivo without the need of a contrast agent. Here, we test this hypothesis further by examining the spatial and detection sensitivity of quench-assisted 1/T1 MRI to strain, age, or retinal cell layer-specific genetic manipulations. Methods We studied: adult wild-type mice; mice at postnatal day 7 (P7); cre dependent retinal pigment epithelium (RPE)-specific MnSOD knockout mice; doxycycline-treated Sod2flox/flox mice lacking the cre transgene; and α-transducin knockout (Gnat1−/−) mice on a C57Bl/6 background. Transretinal 1/T1 profiles were mapped in vivo in the dark without or with antioxidant treatment, or followed by light exposure. We calibrated profiles spatially using optical coherence tomography. Results Dark-adapted RPE-specific MnSOD knockout mice had greater than normal 1/T1 in the RPE and outer nuclear layers that was corrected to wild-type levels by antioxidant treatment. Dark and light Gnat1−/− mice also had greater than normal outer retinal 1/T1 values. In adult wild-type mice, dark values of 1/T1 in the ellipsoid region and in the outer segment were suppressed by 13 minutes of light. By 29 minutes of light, 1/T1 reduction extended to the outer nuclear layer. Gnat1−/− mice demonstrated a faster light-evoked suppression of 1/T1 values in the outer retina. In P7 mice, transretinal 1/T1 profiles were the same in dark and light. Conclusions Quench-assisted MRI has the laminar resolution and detection sensitivity to evaluate normal and pathologic production of free radicals in vivo.
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Affiliation(s)
- Bruce A Berkowitz
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States 2Department of Ophthalmology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Alfred S Lewin
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States
| | - Manas R Biswal
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States
| | - Bryce X Bredell
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Christopher Davis
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Robin Roberts
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
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Berkowitz BA, Bredell BX, Davis C, Samardzija M, Grimm C, Roberts R. Measuring In Vivo Free Radical Production by the Outer Retina. Invest Ophthalmol Vis Sci 2016; 56:7931-8. [PMID: 26670830 DOI: 10.1167/iovs.15-18420] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
PURPOSE Excessive and continuously produced free radicals in the outer retina are implicated in retinal aging and the pathogenesis of sight-threatening retinopathies, yet measuring outer retinal oxidative stress in vivo remains a challenge. Here, we test the hypothesis that continuously produced paramagnetic free radicals from the outer retina can be measured in vivo using high-resolution (22-μm axial resolution) 1/T1magnetic resonance imaging (MRI) without and with a confirmatory quench (quench-assisted MRI). METHODS Low-dose sodium iodate-treated and diabetic C57Bl6/J mice (and their controls), and rod-dominated (129S6) or cone-only R91W;Nrl-/- mice were studied. In dark-adapted groups, 1/T1 was mapped transretinally in vivo without or with (1) the antioxidant combination of methylene blue (MB) and α-lipoic acid (LPA), or (2) light exposure; in subgroups, retinal superoxide production was measured ex vivo (lucigenin). RESULTS In the sodium iodate model, retinal superoxide production and outer retina-specific 1/T1 values were both significantly greater than normal and corrected to baseline with MB+LPA therapy. Nondiabetic mice at two ages and 1.2-month diabetic mice (before the appearance of oxidative stress) had similar transretinal 1/T1 profiles. By 2.3 months of diabetes, only outer retinal 1/T1 values were significantly greater than normal and were corrected to baseline with MB+LPA therapy. In mice with healthy photoreceptors, a light quench caused 1/T1 of rods, but not cones, to significantly decrease from their values in the dark. CONCLUSIONS Quench-assisted MRI is a feasible method for noninvasively measuring normal and pathologic production of free radicals in photoreceptors/RPE in vivo.
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Affiliation(s)
- Bruce A Berkowitz
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States 2Department of Ophthalmology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Bryce X Bredell
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Christopher Davis
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Marijana Samardzija
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Switzerland
| | - Christian Grimm
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Switzerland
| | - Robin Roberts
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
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Clinical evaluation of ultra-high-field MRI for three-dimensional visualisation of tumour size in uveal melanoma patients, with direct relevance to treatment planning. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2016; 29:571-7. [PMID: 26915081 PMCID: PMC4891368 DOI: 10.1007/s10334-016-0529-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 01/14/2016] [Accepted: 01/18/2016] [Indexed: 11/01/2022]
Abstract
OBJECTIVES To assess the tumour dimensions in uveal melanoma patients using 7-T ocular MRI and compare these values with conventional ultrasound imaging to provide improved information for treatment options. MATERIALS AND METHODS Ten uveal melanoma patients were examined on a 7-T MRI system using a custom-built eye coil and dedicated 3D scan sequences to minimise eye-motion-induced image artefacts. The maximum tumour prominence was estimated from the three-dimensional images and compared with the standard clinical evaluation from 2D ultrasound images. RESULTS The MRI protocols resulted in high-resolution motion-free images of the eye in which the tumour and surrounding tissues could clearly be discriminated. For eight of the ten patients the MR images showed a slightly different value of tumour prominence (average 1.0 mm difference) compared to the ultrasound measurements, which can be attributed to the oblique cuts through the tumour made by the ultrasound. For two of these patients the more accurate results from the MR images changed the treatment plan, with the smaller tumour dimensions making them eligible for eye-preserving therapy. CONCLUSION High-field ocular MRI can yield a more accurate measurement of the tumour dimensions than conventional ultrasound, which can result in significant changes in the prescribed treatment.
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30
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Berkowitz BA, Bissig D, Roberts R. MRI of rod cell compartment-specific function in disease and treatment in vivo. Prog Retin Eye Res 2015; 51:90-106. [PMID: 26344734 DOI: 10.1016/j.preteyeres.2015.09.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/26/2015] [Accepted: 09/01/2015] [Indexed: 10/23/2022]
Abstract
Rod cell oxidative stress is a major pathogenic factor in retinal disease, such as diabetic retinopathy (DR) and retinitis pigmentosa (RP). Personalized, non-destructive, and targeted treatment for these diseases remains elusive since current imaging methods cannot analytically measure treatment efficacy against rod cell compartment-specific oxidative stress in vivo. Over the last decade, novel MRI-based approaches that address this technology gap have been developed. This review summarizes progress in the development of MRI since 2006 that enables earlier evaluation of the impact of disease on rod cell compartment-specific function and the efficacy of anti-oxidant treatment than is currently possible with other methods. Most of the new assays of rod cell compartment-specific function are based on endogenous contrast mechanisms, and this is expected to facilitate their translation into patients with DR and RP, and other oxidative stress-based retinal diseases.
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Affiliation(s)
- Bruce A Berkowitz
- Dept. of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI, USA; Dept. Of Ophthalmology, Wayne State University School of Medicine, Detroit, MI, USA.
| | - David Bissig
- Dept. of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Robin Roberts
- Dept. Of Ophthalmology, Wayne State University School of Medicine, Detroit, MI, USA
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31
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Zhao D, Pacheco-Torres J, Hallac RR, White D, Peschke P, Cerdán S, Mason RP. Dynamic oxygen challenge evaluated by NMR T1 and T2*--insights into tumor oxygenation. NMR IN BIOMEDICINE 2015; 28:937-947. [PMID: 26058575 PMCID: PMC4506740 DOI: 10.1002/nbm.3325] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 04/10/2015] [Accepted: 04/14/2015] [Indexed: 05/03/2023]
Abstract
There is intense interest in developing non-invasive prognostic biomarkers of tumor response to therapy, particularly with regard to hypoxia. It has been suggested that oxygen sensitive MRI, notably blood oxygen level-dependent (BOLD) and tissue oxygen level-dependent (TOLD) contrast, may provide relevant measurements. This study examined the feasibility of interleaved T2*- and T1-weighted oxygen sensitive MRI, as well as R2* and R1 maps, of rat tumors to assess the relative sensitivity to changes in oxygenation. Investigations used cohorts of Dunning prostate R3327-AT1 and R3327-HI tumors, which are reported to exhibit distinct size-dependent levels of hypoxia and response to hyperoxic gas breathing. Proton MRI R1 and R2* maps were obtained for tumors of anesthetized rats (isoflurane/air) at 4.7 T. Then, interleaved gradient echo T2*- and T1-weighted images were acquired during air breathing and a 10 min challenge with carbogen (95% O2 -5% CO2). Signals were stable during air breathing, and each type of tumor showed a distinct signal response to carbogen. T2* (BOLD) response preceded T1 (TOLD) responses, as expected. Smaller HI tumors (reported to be well oxygenated) showed the largest BOLD and TOLD responses. Larger AT1 tumors (reported to be hypoxic and resist modulation by gas breathing) showed the smallest response. There was a strong correlation between BOLD and TOLD signal responses, but ΔR2* and ΔR1 were only correlated for the HI tumors. The magnitude of BOLD and TOLD signal responses to carbogen breathing reflected expected hypoxic fractions and oxygen dynamics, suggesting potential value of this test as a prognostic biomarker of tumor hypoxia.
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Affiliation(s)
- Dawen Zhao
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA 75390
| | - Jesús Pacheco-Torres
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA 75390
- Laboratory for Imaging and Spectroscopy by Magnetic Resonance LISMAR, Instituto de Investigaciones Biomédicas “Alberto Sols” CSIC/UAM, Arturo Duperier 4, Madrid 28029, Spain
| | - Rami R. Hallac
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA 75390
| | - Derek White
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA 75390
| | - Peter Peschke
- Clinical Cooperation Unit Molecular Radiooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Sebastian Cerdán
- Laboratory for Imaging and Spectroscopy by Magnetic Resonance LISMAR, Instituto de Investigaciones Biomédicas “Alberto Sols” CSIC/UAM, Arturo Duperier 4, Madrid 28029, Spain
| | - Ralph P. Mason
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA 75390
- To whom correspondence should be addressed: Ralph P. Mason, PhD Department of Radiology UT Southwestern Medical Center 5323 Harry Hines Blvd. Dallas, TX 75390-9058 USA Phone: +1 (214) 648-8926 Fax: +1 (214) 648-2991
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Beeman SC, Shui YB, Perez-Torres CJ, Engelbach JA, Ackerman JJH, Garbow JR. O2 -sensitive MRI distinguishes brain tumor versus radiation necrosis in murine models. Magn Reson Med 2015; 75:2442-7. [PMID: 26175346 DOI: 10.1002/mrm.25821] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 05/28/2015] [Accepted: 05/31/2015] [Indexed: 12/20/2022]
Abstract
PURPOSE The goal of this study was to quantify the relationship between the (1) H longitudinal relaxation rate constant, R1 , and oxygen (O2 ) concentration (relaxivity, r1 ) in tissue and to quantify O2 -driven changes in R1 (ΔR1 ) during a breathing gas challenge in normal brain, radiation-induced lesions, and tumor lesions. METHODS R1 data were collected in control-state mice (n = 4) during three different breathing gas (and thus tissue O2 ) conditions. In parallel experiments, pO2 was measured in the thalamus of control-state mice (n = 4) under the same breathing gas conditions using an O2 -sensitive microprobe. The relaxivity of tissue O2 was calculated using the R1 and pO2 data. R1 data were collected in control-state (n = 4) mice, a glioma model (n = 7), and a radiation necrosis model (n = 6) during two breathing gas (thus tissue O2 ) conditions. R1 and ΔR1 were calculated for each cohort. RESULTS O2 r1 in the brain was 9 × 10(-4) ± 3 × 10(-4) mm Hg(-1) · s(-1) at 4.7T. R1 and ΔR1 measurements distinguished radiation necrosis from tumor (P< 0.03 and P< 0.01, respectively). CONCLUSION The relaxivity of O2 in the brain is determined. R1 and ΔR1 measurements differentiate tumor lesions from radiation necrosis lesions in the mouse models. These pathologies are difficult to distinguish by traditional imaging techniques; O2 -driven changes in R1 holds promise in this regard. Magn Reson Med 75:2442-2447, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Scott C Beeman
- Department of Radiology, Washington University, St. Louis, Missouri, USA
| | - Ying-Bo Shui
- Department of Ophthalmology, Washington University, St. Louis, Missouri, USA
| | | | - John A Engelbach
- Department of Radiology, Washington University, St. Louis, Missouri, USA
| | - Joseph J H Ackerman
- Department of Radiology, Washington University, St. Louis, Missouri, USA.,Department of Chemistry, Washington University, St. Louis, Missouri, USA.,Department of Internal Medicine, Washington University, St. Louis, Missouri, USA.,Alvin J. Siteman Cancer Center, Washington University, St. Louis, Missouri, USA
| | - Joel R Garbow
- Department of Radiology, Washington University, St. Louis, Missouri, USA.,Alvin J. Siteman Cancer Center, Washington University, St. Louis, Missouri, USA
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Diffusion-Sensitized Ophthalmic Magnetic Resonance Imaging Free of Geometric Distortion at 3.0 and 7.0 T. Invest Radiol 2015; 50:309-21. [DOI: 10.1097/rli.0000000000000129] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Ruytenberg T, Webb AG, Beenakker JWM. A multi-purpose open-source triggering platform for magnetic resonance. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 247:15-21. [PMID: 25222861 DOI: 10.1016/j.jmr.2014.08.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 08/19/2014] [Accepted: 08/21/2014] [Indexed: 06/03/2023]
Abstract
Many MR scans need to be synchronised with external events such as the cardiac or respiratory cycles. For common physiological functions commercial trigger equipment exists, but for more experimental inputs these are not available. This paper describes the design of a multi-purpose open-source trigger platform for MR systems. The heart of the system is an open-source Arduino Due microcontroller. This microcontroller samples an analogue input and digitally processes these data to determine the trigger. The output of the microcontroller is programmed to mimic a physiological signal which is fed into the electrocardiogram (ECG) or pulse oximeter port of MR scanner. The microcontroller is connected to a Bluetooth dongle that allows wireless monitoring and control outside the scanner room. This device can be programmed to generate a trigger based on various types of input. As one example, this paper describes how it can be used as an acoustic cardiac triggering unit. For this, a plastic stethoscope is connected to a microphone which is used as an input for the system. This test setup was used to acquire retrospectively-triggered cardiac scans in ten volunteers. Analysis showed that this platform produces a reliable trigger (>99% triggers are correct) with a small average 8 ms variation between the exact trigger points.
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Affiliation(s)
- T Ruytenberg
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - A G Webb
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - J W M Beenakker
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
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High spatial resolution in vivo magnetic resonance imaging of the human eye, orbit, nervus opticus and optic nerve sheath at 7.0 Tesla. Exp Eye Res 2014; 125:89-94. [DOI: 10.1016/j.exer.2014.05.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 05/26/2014] [Accepted: 05/31/2014] [Indexed: 11/17/2022]
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36
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Ophthalmic Magnetic Resonance Imaging at 7 T Using a 6-Channel Transceiver Radiofrequency Coil Array in Healthy Subjects and Patients With Intraocular Masses. Invest Radiol 2014; 49:260-70. [DOI: 10.1097/rli.0000000000000049] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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37
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Duong TQ. Magnetic resonance imaging of the retina: from mice to men. Magn Reson Med 2014; 71:1526-30. [PMID: 23716429 PMCID: PMC3783549 DOI: 10.1002/mrm.24797] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/25/2013] [Accepted: 04/15/2013] [Indexed: 11/09/2022]
Abstract
This mini-review provides an overview of magnetic resonance imaging (MRI) applications to study rodent, cat, non-human primate, and human retinas. These techniques include T(1) - and T(2) -weighted anatomical, diffusion, blood flow, blood volume, blood-oxygenation level dependent, manganese-enhanced, physiological, and functional MRI. Applications to study the retinas in diabetic retinopathy, glaucoma, and retinal degeneration are also reviewed. MRI offers some unique advantages compared with existing imaging techniques and has the potential to further our understanding of physiology and function in healthy and diseased retinas.
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Affiliation(s)
- Timothy Q Duong
- South Texas Veterans Health Care System, Research Imaging Institute, Department of Ophthalmology, University of Texas Health Science Center, San Antonio, Texas, USA
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38
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Emeterio Nateras OS, Harrison JM, Muir ER, Zhang Y, Peng Q, Chalfin S, Gutierrez JE, Johnson DA, Kiel JW, Duong TQ. Choroidal blood flow decreases with age: an MRI study. Curr Eye Res 2014; 39:1059-67. [PMID: 24655028 DOI: 10.3109/02713683.2014.892997] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To verify that a visual fixation protocol with cued eye blinks achieves sufficient stability for magnetic resonance imaging (MRI) blood-flow measurements and to determine if choroidal blood flow (ChBF) changes with age in humans. METHODS The visual fixation stability achievable during an MRI scan was measured in five normal subjects using an eye-tracking camera outside the MRI scanner. Subjects were instructed to blink immediately after recorded MRI sound cues but to otherwise maintain stable visual fixation on a small target. Using this fixation protocol, ChBF was measured with MRI using a 3 Tesla clinical scanner in 17 normal subjects (24-68 years old). Arterial and intraocular pressures (IOP) were measured to calculate perfusion pressure in the same subjects. RESULTS The mean temporal fluctuations (standard deviation) of the horizontal and vertical displacements were 29 ± 9 μm and 38 ± 11 μm within individual fixation periods, and 50 ± 34 μm and 48 ± 19 μm across different fixation periods. The absolute displacements were 67 ± 31 μm and 81 ± 26 μm. ChBF was negatively correlated with age (R = -0.7, p = 0.003), declining 2.7 ml/100 ml/min per year. There were no significant correlations between ChBF versus perfusion pressure, arterial pressure, or IOP. There were also no significant correlations between age versus perfusion pressure, arterial pressure, or IOP. Multiple regression analysis indicated that age was the only measured independent variable that was significantly correlated with ChBF (p = 0.03). CONCLUSIONS The visual fixation protocol with cued eye blinks was effective in achieving sufficient stability for MRI measurements. ChBF had a significant negative correlation with age.
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Falke K, Krüger P, Hosten N, Zimpfer A, Guthoff R, Langner S, Stachs O. Experimental differentiation of intraocular masses using ultrahigh-field magnetic resonance imaging--a case series. PLoS One 2013; 8:e81284. [PMID: 24349051 PMCID: PMC3857191 DOI: 10.1371/journal.pone.0081284] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 10/20/2013] [Indexed: 11/18/2022] Open
Abstract
PURPOSE The case reports presented here were compiled to demonstrate the potential for improved diagnosis and monitoring of disease progress of intraocular lesions using ultrahigh-field magnetic resonance microscopy (MRM) at 7.1 Tesla. METHODS High-resolution ex vivo ocular magnetic resonance (MR) images were acquired on an ultrahigh-field MR system (7.1 Tesla, ClinScan, Bruker BioScan, Germany) using a 2-channel coil with 4 coil elements and T2-weighted turbo spin echo (TSE) sequences of human eyes enucleated because of different intraocular lesions. Imaging parameters were: 40×40 mm field of view, 512×512 matrix, and 700 µm slice thickness. The results were correlated with in vivo ultrasound and histology of the enucleated eyes. RESULTS Imaging was performed in enucleated eyes with choroidal melanoma, malignant melanoma of iris and ciliary body with scleral perforation, ciliary body melanoma, intraocular metastasis of esophageal cancer, subretinal bleeding in the presence of perforated corneal ulcer, hemorrhagic choroidal detachment, and premature retinopathy with phthisis and ossification of bulbar structures. MR imaging allowed differentiation between solid and cystic tumor components. In case of hemorrhage, fluid-fluid levels were identified. Melanin and calcifications caused significant hypointensity. Microstructural features of eye lesions identified by MRM were confirmed by histology. CONCLUSION This study demonstrates the potential of MRM for the visualization and differential diagnosis of intraocular lesions. At present, the narrow bore of the magnet still limits the use of this technology in humans in vivo. Further advances in ultrahigh-field MR imaging will permit visualization of tumor extent and evaluation of nonclassified intraocular structures in the near future.
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Affiliation(s)
- Karen Falke
- Department of Ophthalmology, University of Rostock, Rostock, Germany
| | - Paul Krüger
- Institute of Diagnostic Radiology and Neuroradiology, Greifswald University Hospital, Greifswald, Germany
| | - Norbert Hosten
- Institute of Diagnostic Radiology and Neuroradiology, Greifswald University Hospital, Greifswald, Germany
| | - Annette Zimpfer
- Institute of Pathology, University of Rostock, Rostock, Germany
| | - Rudolf Guthoff
- Department of Ophthalmology, University of Rostock, Rostock, Germany
| | - Sönke Langner
- Institute of Diagnostic Radiology and Neuroradiology, Greifswald University Hospital, Greifswald, Germany
| | - Oliver Stachs
- Department of Ophthalmology, University of Rostock, Rostock, Germany
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Beenakker JWM, van Rijn GA, Luyten GPM, Webb AG. High-resolution MRI of uveal melanoma using a microcoil phased array at 7 T. NMR IN BIOMEDICINE 2013; 26:1864-1869. [PMID: 24123279 DOI: 10.1002/nbm.3041] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/02/2013] [Accepted: 09/04/2013] [Indexed: 06/02/2023]
Abstract
High-field MRI is a promising technique for the characterisation of ocular tumours, both in vivo and after enucleation. For in vivo imaging at 7 T, a dedicated three-element microcoil array was constructed as a high-sensitivity receive-only device. Using a dedicated blink/fixation protocol, high-resolution in vivo images could be acquired within 3 min in volunteers and patients with no requirement for post-acquisition image registration. Quantitative measures of axial length, aqueous depth and lens thickness in a healthy volunteer were found to agree well with standard ocular biometric techniques. In a patient with uveal melanoma, in vivo MRI gave excellent tumour/aqueous body contrast. Ex vivo imaging of the enucleated eye showed significant heterogeneity within the tumour.
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Affiliation(s)
- J W M Beenakker
- C. J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands; Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands
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Filas BA, Shui YB, Beebe DC. Computational model for oxygen transport and consumption in human vitreous. Invest Ophthalmol Vis Sci 2013; 54:6549-59. [PMID: 24008409 DOI: 10.1167/iovs.13-12609] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
PURPOSE Previous studies that measured liquefaction and oxygen content in human vitreous suggested that exposure of the lens to excess oxygen causes nuclear cataracts. Here, we developed a computational model that reproduced available experimental oxygen distributions for intact and degraded human vitreous in physiologic and environmentally perturbed conditions. After validation, the model was used to estimate how age-related changes in vitreous physiology and structure alter oxygen levels at the lens. METHODS A finite-element model for oxygen transport and consumption in the human vitreous was created. Major inputs included ascorbate-mediated oxygen consumption in the vitreous, consumption at the posterior lens surface, and inflow from the retinal vasculature. Concentration-dependent relations were determined from experimental human data or estimated from animal studies, with the impact of all assumptions explored via parameter studies. RESULTS The model reproduced experimental data in humans, including oxygen partial pressure (Po2) gradients (≈15 mm Hg) across the anterior-posterior extent of the vitreous body, higher oxygen levels at the pars plana relative to the vitreous core, increases in Po2 near the lens after cataract surgery, and equilibration in the vitreous chamber following vitrectomy. Loss of the antioxidative capacity of ascorbate increases oxygen levels 3-fold at the lens surface. Homogeneous vitreous degeneration (liquefaction), but not partial posterior vitreous detachment, greatly increases oxygen exposure to the lens. CONCLUSIONS Ascorbate content and the structure of the vitreous gel are critical determinants of lens oxygen exposure. Minimally invasive surgery and restoration of vitreous structure warrant further attention as strategies for preventing nuclear cataracts.
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Affiliation(s)
- Benjamen A Filas
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, Missouri
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Berkowitz BA, Bissig D, Dutczak O, Corbett S, North R, Roberts R. MRI biomarkers for evaluation of treatment efficacy in preclinical diabetic retinopathy. ACTA ACUST UNITED AC 2013; 7:393-403. [PMID: 23786440 DOI: 10.1517/17530059.2013.814639] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
INTRODUCTION One sober consequence of the current epidemic of diabetes mellitus is that an increasing number of people world-wide will partially or completely lose their sight to diabetic retinopathy. Clinically, the sight-threatening complications of diabetes are diagnosed and treated based on visible retinal lesions (e.g., dot-blot hemorrhages or retinal neovascularization). However, such anatomical microvascular lesions are slow to respond with treatment. Thus, there remains an urgent need for imaging biomarkers that are abnormal before retinal lesions are visibly apparent and are responsive to treatment. AREAS COVERED Here, the development of new MRI methods, such as manganese-enhanced MRI, for evaluating early diabetes-evoked retinal pathophysiology, and its usefulness in guiding new treatments for diabetic retinopathy are reviewed. EXPERT OPINION In diabetic retinopathy, not all important diagnostic and prognostic needs are well served by optical methods. In the absence of gross anatomy changes, critical times when drug intervention is most likely to be successful at reducing vision loss are missed by most light-based methods and thus provide little help in guiding diagnosis and treatment. For example, before clinical symptoms, is there an optimal time to intervene with drug therapy? Is a drug reaching its target? How does one assess optimal drug dose, schedule, and routes? How well do current experimental models mimic the clinical condition? As discussed herein, MRI is as an analytical tool for addressing these unmet needs. Future clinical applications of MRI can be envisioned such as in clinical trials to assess drug treatment efficacy, or as an adjunct approach to refine or clarify a difficult clinical case. New MRI-generated hypotheses about the pathogenesis of diabetic retinopathy and its treatment are discussed. In the coming years, a substantial growth in the development and application of MRI is expected to address relevant question in both the basic sciences and in the clinic.
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Affiliation(s)
- Bruce A Berkowitz
- Wayne State University, Department of Anatomy and Cell Biology, Detroit, MI, USA.
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Retrobulbar vasculature using 7-T magnetic resonance imaging with dedicated eye surface coil. Graefes Arch Clin Exp Ophthalmol 2012; 251:271-7. [DOI: 10.1007/s00417-012-2154-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 07/24/2012] [Accepted: 08/29/2012] [Indexed: 10/27/2022] Open
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Zhang Y, Nateras OSE, Peng Q, Kuranov RV, Harrison JM, Milner TE, Duong TQ. Lamina-specific anatomic magnetic resonance imaging of the human retina. Invest Ophthalmol Vis Sci 2011; 52:7232-7. [PMID: 21828153 DOI: 10.1167/iovs.11-7623] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Magnetic resonance imaging (MRI) of the human retina faces two major challenges: eye movement and hardware limitation that could preclude human retinal MRI with adequate spatiotemporal resolution. This study investigated eye-fixation stability and high-resolution anatomic MRI of the human retina on a 3-Tesla (T) MRI scanner. Comparison was made with optical coherence tomography (OCT) on the same subjects. METHODS Eye-fixation stability of protocols used in MRI was evaluated on four normal volunteers using an eye tracker. High-resolution MRI (100 × 200 × 2000 μm) protocol was developed on a 3-T scanner. Subjects were instructed to maintain stable eye fixation on a target with cued blinks every 8 seconds during MRI. OCT imaging of the retina was performed. Retinal layer thicknesses measured with MRI and OCT were analyzed for matching regions of the same eyes close to the optic nerve head. RESULTS The temporal SDs of the horizontal and vertical displacements were 78 ± 51 and 130 ± 51 μm (±SD, n = 4), respectively. MRI detected three layers within the human retina, consistent with MRI findings in rodent, feline, and baboon retinas. The hyperintense layer 1 closest to the vitreous likely consisted of nerve fiber, ganglion cell, and inner nuclear layer; the hypointense layer 2, the outer nuclear layer and the inner and outer segments; and the hyperintense layer 3, the choroid. The MRI retina/choroid thickness was 711 ± 37 μm, 19% (P < 0.05) thicker than OCT thickness (579 ± 34 μm). CONCLUSIONS This study reports high-resolution MRI of lamina-specific structures in the human retina. These initial results are encouraging. Further improvement in spatiotemporal resolution is warranted.
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Affiliation(s)
- Yi Zhang
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas 78229, USA
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Chen J, Wang Q, Chen S, Wickline SA, Song SK. In vivo diffusion tensor MRI of the mouse retina: a noninvasive visualization of tissue organization. NMR IN BIOMEDICINE 2011; 24:447-451. [PMID: 20931570 PMCID: PMC3738013 DOI: 10.1002/nbm.1609] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 07/19/2010] [Accepted: 07/27/2010] [Indexed: 05/30/2023]
Abstract
Diffusion tensor MRI (DTI) is a method for the noninvasive assessment of cellular organization and integrity in vivo. In this study, in vivo DTI was performed to demonstrate its ability to reflect photoreceptor cell alignment in adult C57BL/6 wild-type mice. Age-matched retinal degeneration 1 (rd1) mice were employed as a negative control, i.e. loss of the photoreceptor cell layer. In wild-type mice, DTI-estimated cell alignment suggests that the MR-detected outer retinal layer comprises cells aligning perpendicular to the retinal surface, consistent with the known organization of photoreceptor cells. The MR-detected outer retinal layer exhibits a lower apparent diffusion coefficient and higher fractional anisotropy than the other two MR-detected retinal layers (p < 0.05 for all comparisons). In rd1 mice, the remaining MR-detected retinal layer exhibits different cell alignment, apparent diffusion coefficient and fractional anisotropy from that of the MR-detected outer retinal layer in wild-type mice (p < 0.05 for all comparisons), reflecting the degeneration of photoreceptor cells in rd1 mouse retina. Overall, our findings suggest that in vivo DTI assessment of mouse retina with normal physiology or degenerative pathology is feasible.
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Affiliation(s)
- Junjie Chen
- Department of Medicine, Washington University, St. Louis, MO 63108, USA.
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Malhotra A, Minja FJ, Crum A, Burrowes D. Ocular Anatomy and Cross-Sectional Imaging of the Eye. Semin Ultrasound CT MR 2011; 32:2-13. [DOI: 10.1053/j.sult.2010.10.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
MR oximetry includes methods for assessing tissue oxygenation. This chapter focuses on direct measurements of oxygenation. These can be divided into three methods. The first and most common has been termed BOLD MRI and relates to the quantification of deoxyhemoglobin. The second method uses an injected fluorinated agent which has a T (1) that is sensitive to tissue oxygen levels. The third is a direct measurement of T (1) under conditions where the variation in T (1) can be limited to that caused by changes in pO(2). These conditions can be met in the vitreous of the eye or the cerebrospinal fluids. Such changes in the eye have been called the retinal oxygenation response.
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Affiliation(s)
- Jeff F Dunn
- Department of Radiology, Physiology, and Biophysics, Faculty of Medicine, University of Calgary, Calgary, Canada.
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Maleki N, Dai W, Alsop DC. Blood flow quantification of the human retina with MRI. NMR IN BIOMEDICINE 2011; 24:104-111. [PMID: 20862658 DOI: 10.1002/nbm.1564] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 04/21/2010] [Indexed: 05/29/2023]
Abstract
The purpose of this study was to investigate the feasibility of measuring blood flow to the retina using arterial spin labeling MRI, a quantitative, noninvasive tomographic technique. Blood flow imaging was performed in a single axial slice through both eyes of five healthy volunteers with no history of retinal diseases. The imaging was optimized to minimize the errors from motion and nonuniform magnetic fields caused by proximity to the sinuses. Key hemodynamic factors for flow quantification, including arterial transit delay and the apparent decay time of the signal, were estimated by repeated measurements with different arterial spin labeling timing. A clearly elevated signal, consistent with the anatomical location of the retina, was observed in all subjects. The measured blood flow to a 1 cm × 1.47 cm section of the retina, centered on the fovea, was 1.75 ± 0.54 µL/mm(2) /min (total blood flow of 261 ± 87 µL/min). The arterial transit delay from a labeling plane 5 cm below the slice was 1137 ± 288 ms. These results establish the feasibility of measuring blood flow to the retina with MRI, and support the future characterization of the healthy and diseased ocular circulation with this method.
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Affiliation(s)
- Nasim Maleki
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Boston, MA, USA.
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Magnetic resonance imaging of the anteroposterior position and thickness of the aging, accommodating, phakic, and pseudophakic ciliary muscle. J Cataract Refract Surg 2010; 36:235-41. [PMID: 20152603 DOI: 10.1016/j.jcrs.2009.08.029] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 08/30/2009] [Accepted: 08/31/2009] [Indexed: 11/21/2022]
Abstract
PURPOSE To quantify accommodative and age-related changes in the anteroposterior position and thickness of the ciliary muscle in phakic and pseudophakic eyes. SETTING Department of Surgery/Bioengineering, UMDNJ-Robert Wood Johnson Medical School, Piscataway; Institute of Ophthalmology and Visual Science UMDNJ-New Jersey Medical School, Newark, New Jersey; MRI Research, Inc., Middleburg Heights, Ohio, USA. METHODS Magnetic resonance images were taken of phakic and pseudophakic eyes. RESULTS The cohort comprised 32 phakic volunteers and 8 volunteers with a monocular intraocular lens (IOL) aged 22 to 91 years. No anteroposterior accommodative movement of the ciliary muscle apex occurred in either group. The muscle moved closer to the cornea with advancing age in phakic eyes; IOL implantation returned the muscle to a youthful position. An age-dependent increase in ciliary muscle anteroposterior thickness occurred that was not mitigated by IOL implantation. Muscle thickness increased with accommodation in only phakic eyes. CONCLUSIONS Presbyopia-correction strategies cannot rely on accommodative anterior movement of the ciliary muscle. Forces on the uvea by crystalline lens-pupillary margin contact may increase with accommodation and lens growth, producing accommodative and age-dependent increases in muscle thickness and significant age-dependent anterior muscle displacement. Intraocular lens implantation removed these forces, allowing choroidal elasticity to restore the muscle to a youthful position; however, the increase in thickness was permanent and likely due to an age-dependent increase in connective tissue. This supports the geometric theory of presbyopia development and that the mechanical forces in human accommodation and presbyopia are very different from those in the rhesus monkey model.
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Richdale K, Wassenaar P, Teal Bluestein K, Abduljalil A, Christoforidis JA, Lanz T, Knopp MV, Schmalbrock P. 7 Tesla MR imaging of the human eye in vivo. J Magn Reson Imaging 2010; 30:924-32. [PMID: 19856406 DOI: 10.1002/jmri.21959] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To develop a protocol which optimizes contrast, resolution and scan time for three-dimensional (3D) imaging of the human eye in vivo using a 7 Tesla (T) scanner and custom radio frequency (RF) coil. MATERIALS AND METHODS Initial testing was conducted to reduce motion and susceptibility artifacts. Three-dimensional FFE and IR-TFE images were obtained with variable flip angles and TI times. T(1) measurements were made and numerical simulations were performed to determine the ideal contrast of certain ocular structures. Studies were performed to optimize resolution and signal-to-noise ratio (SNR) with scan times from 20 s to 5 min. RESULTS Motion and susceptibility artifacts were reduced through careful subject preparation. T(1) values of the ocular structures are in line with previous work at 1.5T. A voxel size of 0.15 x 0.25 x 1.0 mm(3) was obtained with a scan time of approximately 35 s for both 3D FFE and IR-TFE sequences. Multiple images were registered in 3D to produce final SNRs over 40. CONCLUSION Optimization of pulse sequences and avoidance of susceptibility and motion artifacts led to high quality images with spatial resolution and SNR exceeding prior work. Ocular imaging at 7T with a dedicated coil improves the ability to make measurements of the fine structures of the eye.
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Affiliation(s)
- Kathryn Richdale
- The Ohio State University College of Optometry, Columbus, Ohio, USA
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