The microstructural corneal changes typically seen in cornea verticillata in both Fabry disease and in amiodarone-induced keratopathy can be successfully visualized by confocal in-vivo microscopy at the level of the basal cell layer. By analogy, with the grading system for cornea verticillata based on slit-lamp microscopy, staging of these deposits in the basal cell layer can also be performed following in-vivo CLSM. The microdots in the anterior stroma as well as the changes observed in the tarsal conjunctiva should be regarded as having less diagnostic value because such changes may also occur in normal subjects. The utility of CLSM as a tool for monitoring ERT in Fabry disease over time needs to be confirmed in studies with larger sample sizes conducted over a longer period.

ObjectivesThis study is designed to examine the feasibility of ophthalmic MRI at 7.0 T using a local six-channel transmit/receive radiofrequency (RF) coil array in healthy volunteers and patients with intraocular masses. Materials and MethodsA novel six-element transceiver RF coil array that makes uses of loop elements and that is customized for eye imaging at 7.0 T is proposed. Considerations influencing the RF coil design and the characteristics of the proposed RF coil array are presented. Numerical electro-magnetic field (EMF) simulations were conducted to enhance the RF coil characteristics. Specific absorption rate (SAR) simulations and a thorough assessment of RF power deposition were performed to meet the safety requirements. Phantom experiments were carried out to validate the EMF simulations and to assess the real performance of the proposed transceiver array. Certified approval for clinical studies was provided by a local notified body prior to the in vivo studies. The suitability of the RF coil to image the human eye, optical nerve and orbit was examined in an in vivo feasibility study including (i) 3D gradient echo imaging (3D GRE), (ii) inversion recovery 3D gradient echo (3D IR-GRE) and (iii) 2D T2 weighted fast spin-echo (2D FSE) imaging. For this purpose healthy adult volunteers (n=17, mean age 3411 years) and patients with intraocular masses (uveal melanoma, n=5, mean age 576years) were investigated. ResultsAll subjects tolerated all examinations well with no relevant adverse events. The sixchannel coil array supports high resolution 3D GRE imaging with a spatial resolution as good as (0.2 x 0.2 x 1.0) mm 3 which facilitates the depiction of anatomical details of the eye. Rather uniform signal intensity across the eye was found. A mean signal-to-noise ratio (SNR) of approximately 35 was found for the lens while the vitreous humor showed an SNR of page 3 approximately 30. The lens-vitreous humor contrast-to-noise ratio was 8, which allows good differentiation between the lens and the vitreous compartment. Inversion recovery prepared 3D GRE using a spatial resolution of (0.4 x 0.4 x 1.0 mm) 3 was found to be feasible. T2-weighted 2D FSE imaging with the proposed RF coil afforded a spatial resolution of (0.25 x 0.25 x 0.7 mm) 3 . ConclusionsThis work provides valuable information on the feasibility of ophthalmic MRI at 7.0 T using a dedicated six-channel transceiver coil array that supports the acquisition of high contrast, high spatial resolution images in healthy volunteers and patients with intraocular masses. The results underscore the challenges of ocular imaging at 7.0 T and demonstrate that these issues can be offset by using tailored RF coil hardware. The benefits of such improvements would be in positive alignment with explorations that are designed to examine the potential of MRI for the assessment of spatial arrangements of the eye segments and their masses with the ultimate goal to provide imaging means for guiding treatment decisions in ophthalmological diseases.

Keratocytes are specialized, neural crest-derived mesenchymal cells occupying approximately 3% of the corneal stromal volume. They reside between the collagen lamellae and are responsible for the secretion of extracellular matrix macromolecules, thus contributing to the corneal transparency and integrity. During the regeneration process after infection, traumata and refractive surgery, the keratocytes undergo transition into divergent phenotypes, which are referred to as "activated keratocytes". Quite shortly after injury, the keratocytes lose their quiescence, enter into the cell cycle and migrate toward the site of injury. In certain types of injury, which affect the integrity of basement membrane, activated keratocytes also participate in wound closure by production of α-smooth muscle actin (α-SMA). Since the activated keratocytes are the major cell type contributing to tissue repair during corneal wound healing, their morphological and biochemical properties have been studied in details in experimental studies using light and electron microscopy. More recently, emerging of in vivo microscopy techniques has opened new possibilities to investigate cornea in vivo. The non-invasive nature of this imaging modality enables repeated examination of the same tissue over time and is an ideal tool to rapidly and accurately investigate corneal wound healing. However, the in vivo data on activated keratocytes are not as uniform as data from experimental ex vivo studies. There is still inconsistency in the literature findings on activated phenotypes, and often the described morphologies cannot be appreciated in in vivo images. In this article, a literature review was performed in order to interpret the morphology of different activated phenotypes, based on biological processes underlying the morphological alterations.

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Definitions of tortuosity specifying short or long-range tortuosity and considering only the most tortuous nerve in an image improved the agreement in tortuosity grading among a group of expert observers. These definitions could improve accuracy and consistency in quantifying subbasal nerve tortuosity in clinical studies.

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Choroidal melanoma is the most frequently occurring intraocular tumor in adults. The aim of this work is to assess the potential of state-of-the art in-vivo and ex-vivo imaging modalities for the characterization of choroidal melanoma. Multimodal imaging of a choroidal melanoma was performed in a 53-year-old male patient. In-vivo ophthalmoscopy, ultrasound microscopy, duplex ultrasound, and 7.0 T MRI were performed. Ex-vivo examination of the enucleated eye included 7.0 and 9.4 T magnetic resonance microscopy as well as histopathology with hematoxylin and eosin staining. Imaging of choroidal melanoma with ultrahigh field MRI and duplex sonography provides detailed morphologic and functional information of the eye. High-spatial-resolution MRI at 9.4 T shows details of the internal texture of melanoma and other structures of the eye with an in-plane spatial resolution of 32 μm. Ultrahigh field in-vivo MRI at 7.0 T and ex-vivo MRI at 7.0 and 9.4 T correlate well with histologic evaluation. In-vivo ultrahigh field MRI is an emerging technique for the characterization and staging of ocular tumors. The combination of in-vivo ultrahigh-field MRI and duplex sonography has the potential to complement or even substitute complex and invasive biopsies.

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