Morphological MR imaging of the articular cartilage of the knee at 3T-comparison of standard and novel 3D sequences.

Jan L Gielen,Pieter Van Dyck,Paul M Parizel,Kristien Wouters,Filip M Vanhoenacker,David M Grodzki,Floris Vanhevel

doi:10.1007/s13244-015-0405-1

Abstract

ObjectivesThis study sought to compare various 3D cartilage sequences and to evaluate the usefulness of ultrashort TE (UTE) imaging, a new technique to isolate signal from the osteochondral junction.MethodsTwenty knees were examined at 3 T with 3D spoiled GRE (FLASH), double-echo steady-state (DESS), balanced SSFP, 3D turbo spin-echo (TSE), and a prototype UTE sequence. Two radiologists independently evaluated all images. Consensus readings of all sequences were the reference standard. Statistical analysis included Friedman and pairwise Wilcoxon tests. Retrospective analysis of UTE morphology of osteochondral tissue in normal and abnormal cartilage seen at conventional MR was also performed.ResultsThree-dimensional TSE was superior to other sequences for detecting cartilage lesions. FLASH and DESS performed best in the subjective quality analysis. On UTE images, normal cartilage exhibited a high-intensity linear signal near the osteochondral junction. Retrospective analysis revealed abnormal UTE morphology of the osteochondral junction in 50 % of cartilage lesions diagnosed at conventional MR.ConclusionsCartilage imaging of the knee at 3 T can be reliably performed using 3D TSE, showing high accuracy when compared to standard sequences. Although UTE depicts signal from the deep cartilage layer, further studies are needed to establish its role for assessment of cartilage.Main Messages• MRI is the best available imaging method for assessment of knee cartilage.• Cartilage imaging can be reliably performed using 3D TSE.• UTE cannot be used as a single sequence to assess cartilage.

Highlights

Magnetic resonance (MR) imaging is generally regarded as the best available noninvasive method for evaluating injury and repair of the articular cartilage of the knee [1,2,3]
Cartilage imaging of the knee at 3 T can be reliably performed using 3D turbo spin-echo (TSE), showing high accuracy when compared to standard sequences
ultrashort TE (UTE) depicts signal from the deep cartilage layer, further studies are needed to establish its role for assessment of cartilage

Summary

Introduction

Magnetic resonance (MR) imaging is generally regarded as the best available noninvasive method for evaluating injury and repair of the articular cartilage of the knee [1,2,3]. Gradient-echo (GRE) sequences were the first 3D sequences used for cartilage imaging [4, 7, 8] They are classically divided into dark fluid sequences (e.g. spoiled gradient echo or FLASH) and bright fluid sequences (e.g. double echo steady-state or DESS) based upon the signal intensity of synovial fluid [4, 8]. These traditional GRE methods have been shown to be highly accurate for cartilage lesions in various studies and are still considered the standard of reference for highresolution 3D isotropic imaging of cartilage [5,6,7,8]. Major disadvantages of 3D GRE imaging include their sensitivity to susceptibility artefacts and their suboptimal tissue contrast [4,5,6,7,8]

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