Journal de radiologie OMICS

Abstrait

Ultrashort TE (UTE) Imaging of the Knee Cartilage at 3T

Song Gao, Shanglian Bao, Christine B Chung, Graeme M Bydder and Jiang Du

While MR imaging has emerged as the imaging method of choice for diagnosis of cartilage disease, the deep radial and calcified layers of cartilage are difficult to image with conventional MRI because of their short T2 relaxation times. The imaging of cartilage injury and osteoarthritis (OA) has therefore focused on the superficial layers of cartilage. We describe herein the implementation of Ultrashort Echo Time (UTE) pulse sequences with Echo Times (TEs) as low as 8 μs on a clinical 3T scanner. Various adaptations were made to the regular UTE acquisition in order to optimize image contrast between the deep layers and superficial layers of cartilage. These modifications included multiple gradient echo UTE acquisition with and without fat saturation, and multiple spin echo UTE acquisition. The efficacy of these techniques in depicting the targeted tissues was demonstrated through imaging of cadaveric samples and healthy volunteers. Excellent depiction of these different regions was obtained, enhanced particularly with fat suppression and later echo subtraction methods. Quantitative measurements showed that while UTE Free Induction Decay (FID) acquisition provided the highest signal-to-noise ratio, both fat suppression and later echo subtraction enhanced the contrast between the deep and superficial layers of cartilage.