Synopsis

Keywords: Cancer, Whole Body

Water-Fat Imaging (WFI) based on chemical shifts can provide excellent separation of water and fat in tissue. This work investigated the application of WFI to spinal diseases. The diagnosis performances were compared with the T1-weighted (T1W) and T2-weighted short-TI-inversion-recovery (T2W STIR) sequence. For hyperosteogeny, spinal metastasis, and disc herniation, the WFI showed comparable performance as the combination of T1W and T2W STIR imaging within a much shorter acquisition time.

Summary of Main Findings

For common spinal diseases, WFI FSE T2 weighted can replace T1-weighted and T2-weighted STIR while reducing the total scanning time.

Introduction

There exist different types of fat-suppression techniques, including chemical shift selective fat saturation (CHESS), short inversion time inversion recovery (STIR), and the water-fat imaging technique (WFI). The WFI is a chemical shift-based water-fat separation technique that exploits the chemical shift between protons of water and fat to decompose the signal from these two tissues in the same voxel, producing four image sets: in-phase (IP, equivalent to standard non-fat suppressed images), out-of-phase (OP), water-only, and fat-only images. Whole-body magnetic resonance imaging (WB-MRI) has become increasingly popular during the past decades[1,2]. The absence of radiation exposure and contrast-agent administration provides advantages in addition to high sensitivity to depiction of bone, soft tissue, and visceral structures. Whole-spine scanning is essential for whole-body magnetic resonance imaging, which was limited by scanning time. Applying WFI and AI-assisted Compressed Sensing (ACS) technology can significantly shorten the scanning time and provide a variety of images simultaneously. The purpose of this study was to compare the diagnostic performance of WFI Fast-Spin-Echo T2-weighted imaging (FSE T2WI) with conventional T1-weighted (T1W) and T2-weighted (T2W) STIR imaging in spinal disease detection.

Materials and methods

Between September 2022 and October 2022, 12 patients who had undergone whole-spine MRI performed on a 3T MR system ((uMR Omega, United Imaging Healthcare, Shanghai, China)) were enrolled. Three diseases were assessed, including hyperosteogeny, spinal metastasis, and disc herniation. The following sagittal imaging sequences were evaluated: T1W, T2W-STIR, and WFI FSE T2W. The whole spine scan was divided into three sections. The total scanning time of WFI FSE T2W sequence was 5min03s. The total scanning time of T1W and T2W STIR sequences was 7min21s. Detailed protocols are shown in Table 1. Two radiologists independently evaluated each image set for lesions. The Kappa test was used to analyze the intra-observer and inter-observer consistency of bone lesion assessment and to evaluate the performance of WFI FSE T2WI on spine diseases.

Results

The intra- and inter-obsevers reliabilities were excellent.. The consistency of the evaluation of vertebral hyperosteogeny, spinal metastasis, and disc herniation by T1WI, T2W STIR images, and WFI FSE T2WI for observer 1 was 0.936, 0.932, and 0.931, respectively. The consistency of the evaluation of vertebral hyperosteogeny, spinal metastasis, and disc herniation by T1WI, T2W STIR, and WFI FSE T2WI for observer 2 was 0.926, 0.946, and 0.909, respectively. The consistency of vertebral hyperosteogeny, spinal metastasis, and disc herniation by WFI FSE T2WI between observers 1 and 2 were 0.974, 0.871, and 0.945, respectively.

Discussion and Conclusions

WFI FSE T2-weighted images could provide a variety of comparisons(IP, OP, Water and Fat). The WFI sequence provides a variety of contrast images through one scan, which is beneficial to detect lesions. The diagnostic performance of WFI FSE T2 weighted imaging was comparable to that of conventional T1WI and T2WI-STIR in detecting spinal diseases.

Acknowledgements

No acknowledgement found.