Diffusion-weighted imaging of the head and neck with HASTE: influence of imaging parameters on image quality

Abstract

Half-Fourier single-shot turbo spin-echo (HASTE) can be applied to diffusion-weighted (DW) imaging of the head and neck. However, HASTE DW imaging has certain drawbacks, such as severe blurring and low signal-to-noise ratio (SNR). The purpose of this study was to evaluate the influence of imaging parameters on image quality using phantoms. We also evaluated the discrimination ability of the apparent diffusion coefficient (ADC) in HASTE DW imaging to assess whether the technique is applicable to head and neck lesions. The modulation transfer function (MTF), SNR, and ADC were compared using dedicated phantoms to evaluate the influence of matrix size (192 × 192 and 256 × 256) and receiver bandwidth (RBW 200, 400, 600, and 789 Hz/pixel) on HASTE DW images. A wide RBW setting tended to improve the MTF, regardless of the matrix size and phase-encoding direction. In contrast, a wide RBW setting tended to impair the SNR, regardless of the matrix size. At the same RBW setting, the MTF and SNR for a matrix size of 192 × 192 were higher than those for a matrix size of 256 × 256. A wide RBW setting tended to improve the discrimination ability of ADCs among the substances, regardless of the matrix size. A wide RBW and small matrix size improved the MTF and SNR of HASTE DW images. A wide RBW also improved the discrimination ability of the ADC. Therefore, HASTE DWI should be performed with a wide RBW setting.