In vivo MRI of the human finger at 7 T

Abstract

PurposeTo demonstrate a dedicated setup for ultrahigh resolution MR imaging of the human finger in vivo.MethodsA radiofrequency coil was designed for optimized signal homogeneity and sensitivity in the finger at ultrahigh magnetic field strength (7 T), providing high measurement sensitivity. Imaging sequences (2D turbo‐spin echo (TSE) and 3D magnetization‐prepared rapid acquisition gradient echo (MPRAGE)) were adapted for high spatial resolution and good contrast of different tissues in the finger, while keeping acquisition time below 10 minutes. Data was postprocessed to display finger structures in three dimensions.Results3D MPRAGE data with isotropic resolution of 200 µm, along with 2D TSE images with in‐plane resolutions of 58 × 78 µm2 and 100 × 97 µm2, allowed clear identification of various anatomical features such as bone and bone marrow, tendons and annular ligaments, cartilage, arteries and veins, nerves, and Pacinian corpuscles.ConclusionUsing this dedicated finger coil at 7 T, together with adapted acquisition sequences, it is possible to depict the internal structures of the human finger in vivo within patient‐compatible measurement time. It may serve as a tool for diagnosis and treatment monitoring in pathologies ranging from inflammatory or erosive joint diseases to injuries of tendons and ligaments to nervous or vascular disorders in the finger. Magn Reson Med 79:588–592, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Tactile innervation densities across the whole body

“…In support of this idea, Cauna and Mannan (30) counted Pacinian corpuscles in the radial half of a foetal index finger and found 178 in total, in almost perfect agreement with Johansson's estimates. More recently, it has been shown that Pacinian corpuscles can be resolved using high-field MRI (31,32), but this technique has not yet been used to establish precise counts. Receptive fields of the type I fibers on the glabrous skin of the hand are small, circular, and well-defined with a mean area of 13 mm 2 for the FAI and 11 mm 2 for the SAI fibers.…”

Assessing spectral imaging of the human finger for detection of arthritis

“…At each wavelength, 10 8 photons were tracked until detection or their weight reaching 0. The finger geometries simulated were based on an ultrahigh resolution in-vivo MRI image of a human finger, obtained at 7 T with a dedicated finger radio frequency coil [18]. We performed tissue segmentation on the MRI data, resulting in a geometry with a spatial resolution (voxel size) of 0.2 mm consisting of 11 different tissues: bone, cartilage, synovial fluid (SF), synovial membrane (SM), tendon, artery, vein, subcutis, dermis, epidermis, and nerve.…”

“…These drawbacks were addressed in [17]. Realistic human joint models and tissue distributions were constructed from an in-vivo MRI scan of a human index finger [18] and used for more detailed simulations of healthy and affected fingers. The realistic finger anatomy involving all finger tissues lead to more reliable simulation results, clarifying if a realistic joint anatomy transmits enough light to enable the detection of RA.…”

Automatic skin lesion area determination of basal cell carcinoma using optical coherence tomography angiography and a skeletonization approach: Preliminary results

“…Non‐invasive, more accurate imaging techniques are therefore highly urgent. Magnetic resonance imaging , computed tomography angiography and ultrasound have been reported to visualize skin vasculature, but they have limited resolution which is not high enough to reveal the microvasculature in the superficial layer of skin.…”