While quantitative MR techniques at 7 T for imaging hip cartilage have been previously reported ¹, the applicability of conventional transverse relaxation time (T2) mapping techniques based on multi-echo multi-slice spin echo sequences (CPMG) are generally compromised due to specific absorption rate (SAR) issues at ultra-high fields (UHF). Recently, a triple-echo steady state (TESS) relaxometry method has been introduced as a fast and in particular B1-insensitive alternative ². So far, the TESS method has only been evaluated for regions with rather small cross-section like brain ³ and wrist ⁴ at 7 T. The aim of this preliminary study was the assessment of TESS T2 relaxometry in pelvic imaging in comparison to standard CPMG as a potential candidate to improve workflow in quantitative hip MRI protocols at 7 T.After protocol optimization in two pilot subjects, a total of eight healthy volunteers (5 male and 3 female, 21-39 years, BMI: 19.8-26.3 kg/m²) were included in this study after signing informed consent. All subjects were imaged at their left hip using a whole-body research system (Magnetom 7T, Siemens Healthcare GmbH, Germany) and an in-house developed 8-channel RF transmit/receive body coil consisting of two arrays with four elements each placed ventrally and dorsally on the pelvis and operated in CP²⁺ transmission mode. Flip angle maps obtained with the dual refocusing echo acquisition mode (DREAM) technique were used to assess the B₁ homogeneity and performance. Acquisition time of both mapping techniques was kept similar and clinically reasonable with 6:00 min (TESS) and 4:53 min (CPMG), respectively, for obtaining a high spatial resolution of 0.5 x 0.5 x 2.5 mm³. Main difference between both methods was the spatial coverage as CPMG would need to be repeated 5 times to yield the same spatial coverage. Sequence parameters are given in Figure 1. Images from the first CPMG echo were not considered for calculating T2 times. A qualitative analysis focused on the homogeneity of the signal in the hip-joint region and regarding artifacts affecting image quality, as well as delineation of acetabular and femoral cartilage. T2 relaxation times were measured by manually drawing regions of interest (ROIs; approximately 200 pixels each) in both acetabular and femoral cartilage in central regions of the hip joint, as well as in two adjacent slices 5 mm next to the center slice.For the TESS sequence a minimum TR/TE in combination with water excitation pulse and PAT averaging suppressed motion and pulsation artifacts efficiently and yielded best image quality during protocol optimization. Both TESS and CPMG images were of high quality, rendering a homogeneous signal in the hip-joint region and allowed a good delineation of acetabular and femoral cartilage (Figure 2). Quantitatively, mean T2 values measured by CPMG were consistently higher compared to those measured with TESS in both regions: 43.3±7.2 ms vs. 19.2±5.3 ms for acetabular cartilage, and 41.4±5.4 ms vs. 21.7±5.1 ms for femoral cartilage (cf. Figure 3). This difference was more pronounced for the 5 male subjects (factor of 2.4 between TESS and CPMG for acetabular, and factor of 1.9 for femoral cartilage) than for the 3 female subjects (factors of 1.9 and 1.8, respectively). B₁ performance was also better by approximately 23% in the female subjects. As shown in Figure 4, no correlation between both methods was found. A comparison of intra-individual T2 values between three adjacent slices (ratio of maximum and minimum T2 values per subject) yielded a 20-25% higher mean deviation for the TESS sequence (acetabular: 1.6±0.3; femoral: 1.5±0.3) compared to CPMG (acetabular: 1.3±0.1 femoral: 1.2±0.1).Compared to CPMG, TESS provides systematically reduced T2 values in both hip cartilage layers, in line with previously reported differences between both methods for brain and wrist at 7 T ^3,4 as well as for knee cartilage at 3 T ⁵. The strong overestimation of T2 could be due to contributions from stimulated echoes as a result from imperfect refocusing pulses (120° effective, cf. Figure 1) in multi-echo spin echo sequences ⁶. While B₀- and B₁-insensitivity ² along with a 5-fold better spatial coverage with TESS seem to be highly advantageous to improve workflow in UHF hip protocols, in particular with regard to SAR limitations, the increased intra-individual deviation of T2 values needs further investigation. A follow-up study will be performed to test the methods for reproducibility, and to evaluate the ability of TESS to distinguish between healthy cartilage and lesions or repair tissue in the hip joint.