7.1 T MRI to Assess the Anterior Segment of the Eye

Abstract

Micro-MRI allows ex vivo and in vivo visualization and quantification of the spatial arrangement of the anterior eye segment. Imaging of the retroiridian region, including the entire crystalline lens, overcomes a number of major limitations in the quantitative evaluation of the anterior segment.

Magic Angle–Enhanced MRI of Fibrous Microstructures in Sclera and Cornea With and Without Intraocular Pressure Loading

“…[18][19][20][21][22][23] However, owing to the limited intrinsic MRI properties of short transverse relaxation times (T2 or T2*) in the scleral and corneal tissues, in conventional MRI sequences such as T2-or T2*-weighted imaging, the corneoscleral shell possesses low signal intensity and appears dark in the images. 23,24 To date, the highest-resolution MRI study of the globe 19 has required exogenous contrast agents and coatings to delineate the corneoscleral shell from the dark surroundings. To the best of our knowledge, none of the techniques aforementioned has been able to visualize the internal structures of the sclera or cornea, or the effects of intraocular pressure (IOP) alterations on these tissues.…”

High resolution MR eye protocol optimization: Comparison between 3D-CISS, 3D-PSIF and 3D-VIBE sequences

“…RARE sequences (FSE, TSE) can reduce total acquisition time by filling multiple lines of kspace with each acquisition and were reported for eye imaging. RARE sequences with higher ETL factors depict short T2 structures of the eye with inferior delineation [23,31]. On the other hand, T1w sequences in SE, TSE and GRE techniques were commonly used in pre and post paramagnetic contrast agent imaging [5,6,11e14,30,32,33].…”

“…As a result, different weighting techniques, such as T1, T2, and diffusion weighting, can reveal details of the eye's structures [1,2,5,23e30]. Particularly, T1-weighted (T1w) images can provide better anatomical detail but the strong orbital fat signal can over-saturate smaller adjacent structures [5,6,29,31]. T2-weighting can improve visualization of the inner surface of the globe, because of the bright vitreous signal, but is vulnerable to motion artifacts, H 0 artifacts and has lower SNR [22,31,32].…”

Whole-globe biomechanics using high-field MRI

“…MRI offers practically unlimited penetration depth for ocular imaging (Duong et al, 2008; Langner et al, 2010), and with improvements in MRI field strength it is now possible to obtain μm-resolution scans without contrast agents (Ho et al, 2016; Ho et al, 2014b). In fact, we recently demonstrated that MRI can be used to image the microstructure of the sclera and lamina cribrosa (Ho et al, 2014b).…”