Quantitative MRI measurements of the Achilles tendon in spondyloarthritis using ultrashort echo times

Abstract

Objectives: Tendon involvement is common in spondyloarthritis. The MRI signal from the Achilles tendon has been used to quantify mechanical tendinopathy; however, conventional MRI is limited by the short T 2 of normal tendon. Short and ultrashort echo time (UTE) MRI have the potential to better measure signal intensity reflecting changes in T 2 or gadolinium enhancement. Furthermore, UTE images could be used for normalisation to reduce variability. The aim of this work was to investigate such techniques in patients with spondyloarthritis (SpA). Methods: The Achilles tendons of 14 healthy volunteers and 24 patients with symptomatic spondyloarthritis were studied. Combined UTE (TE50.07 ms) and gradient echo (TE54.9 ms) images were acquired before and after intravenous gadolinium together with pre-contrast gradient echo images (TE52 ms). The signal intensity from a region of interest in the Achilles tendon above the calcaneus was measured. The relative enhancement at echo times of 0.07 ms (RE 0.1 ) and 4.9 ms (RE 5 ) were calculated. The ratios of the signal intensities from both 4.9 ms and 2 ms gradient echo images to the signal intensity from the UTE image were calculated (RTE 5 and RTE 2 respectively). Results: Interobserver intraclass correlation coefficients were excellent ($0.97). The contrast-to-noise ratio was higher for enhancement on UTE images than on gradient echo images. RE 0.1 , RTE 5 and RTE 2 were significantly higher in SpA patients than controls. Conclusion: Signal intensity ratios using UTE images allow quantitative measurements to be made which are sensitive to tendon T 2 or contrast enhancement and which are increased in spondyloarthritis. They therefore have the potential for use as measures of tendon disease in spondyloarthritis.

Short‐term exercise‐induced changes in hydration state of healthy achilles tendons can be visualized by effects of off‐resonant radiofrequency saturation in a three‐dimensional ultrashort echo time MRI sequence applied at 3 tesla

“…The possibility of obtaining signal from healthy tendinous tissue with UTE sequences enables a further quantitative assessment of the Achilles tendon by evaluation of different MR specific parameters such as T2*‐ and T1 relaxation times or magnetization transfer . In this context, several studies report on MT effects in human Achilles tendon that allow to evaluate interactions between free water protons and macromolecules within the tendon .…”

“…Applying the proposed technique the observed changes in signal yield are based on both magnetization transfer and direct saturation effects indicating variations in the amount and interaction of water protons and macromolecules within the tendon. The possibility of obtaining signal from healthy tendinous tissue with UTE sequences enables a further quantitative assessment of the Achilles tendon by evaluation of different MR specific parameters such as T2*-and T1 relaxation times or magnetization transfer (12)(13)(14)(15)(16)24,25). In this context, several studies report on MT effects in human Achilles tendon that allow to evaluate interactions between free water protons and macromolecules within the tendon (12,13,15).…”

Gluteal Tendinopathy: A Review of Mechanisms, Assessment and Management

“…Short echo time (STE) and ultrashort echo time (UTE) techniques, with or without the use of intravenous gadolinium, provide superior enhancement of signal changes and detection of tendon pathology [66]. MRI has the advantage of allowing assessment of both direct signs of gluteal tendinopathysuch as soft tissue oedema, tendon thickening, intrasubstance signal abnormality and focal discontinuity or absence of tendon fibres-and associated indirect signs, including fatty atrophy of the GMed and GMin muscles [17].…”

Quantitative Imaging in Inflammatory Arthritis: Between Tradition and Innovation

“…110 Shortly afterward, the same authors, examining 14 healthy volunteers and 24 patients with spondyloarthritis, proposed a quantitative evaluation of Achilles tendon involvement measuring the relative enhancement on a single-slice ROI. 111 Despite these promising results, it must be noted that artifacts due to eddy current may hamper 2D-UTE imaging. 112 Aiming to overcome such shortcoming, recently, the 3D-UTE-Cones method was proposed.…”