8 channel cardiac coil

All FAI patients underwent an MR-exam of the symptomatic hip joint using a 3-Tesla MR-scanner (MR750, GE Healthcare, Waukesha, WI) and an 8 channel cardiac coil (GE Healthcare, Waukesha, WI). Each FAI patient was positioned supine in the MR-Scanner and secured with straps. In addition, each FAI patient’s feet were secured to minimize any hip rotation during scanning. The MR-protocol included a combined T_1ρ/T₂ sequence used to assess cartilage composition (Li et al., 2014 ; Wyatt et al., 2015 (link)). For this study, acetabular and femoral cartilage T_1ρ and T₂ relaxation times were estimated and used to provide an indirect measurement of the proteoglycan content and collagen structure, respectively, where an increase in T_1ρ or T₂ relaxation times indicates an alteration in the proteoglycan content or collagen network within the articular cartilage. An atlas-based algorithm was used to perform automatic segmentation of the acetabular and femoral cartilage segmentation and corresponding T_1ρ and T₂ relaxation time estimation (Gallo et al., 2016 (link)). Acetabular and femoral segmentations were then divided into eight sub-regions (Karupppasamy et al., 2013 (link)), where sub-regions with less than 50 pixels over all segmented slices were not analyzed (Figure 1).

Complete radiographs of the affected hip including anteroposterior, frog lateral, and 45-degree Dunn lateral views were obtained on all patients. 3.0T MRI scans of the affected hip were also obtained prior to surgery using an 8-channel cardiac coil (GE Healthcare, Waukesha, WI). The MRI protocol included triplanar 2D intermediate-weighted (IW) fat-saturated fast spin echo (FSE).^{22 (link)}

In a third set of experiments, we acquired in vivo human cardiac data during diastole using a spin-echo EPI sequence with parameters that are typical for a myocardial arterial spin labeling experiment (51 (link)). Data was acquired on a GE 3T Signa HDx scanner with an 8-channel cardiac coil. The acquisition used FOV = 280 mm × 140 mm; matrix size = 128 × 64; slice thickness = 10 mm; TR = 55 msec; TE = 32.9 msec; velocity cutoff = 5 cm/s; no parallel imaging acceleration (R = 1); and 5/8ths partial Fourier sampling. ACS data was acquired using the same interleaved 2R-shot EPI prescan as used for DPG (11 (link)), but with 5/8ths partial Fourier sampling. Data was acquired with a double-oblique slice orientation to achieve a mid-short axis view.