The effect of magnetization transfer in meniscal fibrocartilage

Abstract

Magnetic resonance imaging of the knee was performed in 28 patients (ages 15-72 years), using a 1.5-T unit. Volume gradient echo (3D GRASS) acquisition with and without presaturation off-resonance RF pulse was used to evaluate magnetization transfer (MT) effects, determined by placing regions of interest on muscle, fat, hyaline, and fibrocartilage; the percent change in signal intensity was calculated and compared using a paired two-sample t test. An in vitro study of the normal meniscus from a cadaver containing a scalpel cut extending to an articular surface was performed to observe the relative improvement in contrast in the presence of a small meniscal defect. MR imaging of the specimen was performed using an Omega CSI 2.0-T system (General Electric Medical Systems, Fremont, CA). Analysis of clinical images resulted in signal loss, compared to that of the identically timed and tuned non-MT images of 47 +/- 5, 8 +/- 5, 49 +/- 5, and 57 +/- 7% for muscle, fat, articular cartilage and fibrocartilage, respectively. Application of MT improved the depiction of the artificially introduced meniscal defect. Meniscal fibrocartilage demonstrates significant MT effect after application of off-resonance RF presaturation, which may improve visualization of meniscal defects.

Macromolecular fraction (MMF) from 3D ultrashort echo time cones magnetization transfer (3D UTE-Cones-MT) imaging predicts meniscal degeneration and knee osteoarthritis

“…However, the functional use of cartilage MTR values is limited 12 . In regards to meniscus, MT imaging has been less studied since meniscal MTR and MT modeling are challenging 14 . The fundamental technical challenge is related to the meniscal structure.…”

Protein Mediated Magnetic Coupling between Lactate and Water Protons

“…Magnetic cross-relaxation between mobile water protons and immobile protons is present in model membrane systems (1), cross-linked bovine serum albumin (BSA) (2), polysaccharide gels (3), hydrated starch (4), and biological tissue (5)(6)(7)(8). The immobilized molecules in these aqueous heterogeneous systems reduce the water-macromolecule correlation time into the spin-diffusion region where the intermolecular NOE is negative (9,10).…”

Magnetization Transfer in Human Achilles Tendon Assessed by a 3D Ultrashort Echo Time Sequence: Quantitative Examinations in Healthy Volunteers at 3T

“…Those protons show a much broader absorption line shape in the frequency domain than the bulk water protons used for proton magnetic resonance imaging in clinical settings. Comparison of the signal obtained with and without off-resonance preparation pulses (MT pulses) allows for interpretation of interactions between both proton compartments [2,17,20,21]. The aim of this study was to test the applicability of a 3D UTE sequence combined with an optional MT preparation pulse to characterize healthy Achilles tendons in-vivo.…”