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

Abstract

MT effects in human Achilles tendons can be reliably assessed in-vivo using a 3D UTE sequence at 3 T. All healthy tendons showed similar MTR values (coefficient of variation 10.0 ± 1.2 %). The examined patient showed a clearly different MT effect revealing a changed microstructure in the case of tendinopathy.

Quantitative magnetization transfer ultrashort echo time imaging using a time‐efficient 3D multispoke Cones sequence

“…The MTR values reported by Springer's group are 0.32 (2 kHz offset) and 0.24 (5 kHz offset), where are lower than the values in our study because of a much lower MT power of 220 and a smaller TR of 11 ms (21). Additional experiments with similar sequence parameters are needed for more systematic comparison with past MT modeling and MTR results (21,22).…”

Achillodynia - Radiological Imaging of Acute and Chronic Overuse Injuries of the Achilles Tendon

“…In a number of studies, the effective transverse relaxation time (T2*) of healthy and degenerative tendons was examined. Differences in the T2* relaxation time were seen both in healthy and degenerated tendons depending on the tendon region (e. g. insertion, muscle-tendon complex, midportion) [73,74]. In studies assuming a monoexponential signal decay, the T2* time at 3 T in the mid-portion of a healthy Achilles tendon in vivo was approx.…”

“…On the other hand, UTE sequences also allow quantitative evaluation of different MRspecific tissue characteristics. Essentially, known methods have been applied to UTE imaging so that in particular T1, T1rho, T2* and magnetization transfer (MT) effects can be evaluated [70][71][72][73][74][75]. In a number of studies, the effective transverse relaxation time (T2*) of healthy and degenerative tendons was examined.…”

“…In studies assuming a monoexponential signal decay, the T2* time at 3 T in the mid-portion of a healthy Achilles tendon in vivo was approx. 1.5 ms [74,76]. However, more recent studies regarding the T2* effect assume a biexponential signal decay from which a long and short T2* component can be derived [70,73].…”

“…Using select and varied parameters, both the amount of free and bound water and the exchange constants can be quantified and used as absolute parameters. A simpler possibility that is much more suitable for the clinical routine is the pixel-wise calculation of a so-called MT quotient from the images with and without an MT preparation pulse [72,74]. Tendons with symptomatic tendinosis have significantly lower MT quotients than healthy or asymptomatic tendons [72] ( • " Fig.…”