Flour Pads: Devices to Improve CHESS Fat Suppression

Abstract

Purpose: We compared the suppression of lingering fat signals in chemical shift selective (CHESS) images by pads filled with flour and pads filled with rice in a phantom and human subjects.Materials and Methods: First, we prepared a phantom by creating an empty space in a mass of lard and filling the space with air, rice, or flour. Then, we obtained MR images of the phantoms in the center of the magnetic field and at a position 8 cm to the left (off-center) to compare lingering fat signals. MR images of the knee were obtained in 10 healthy volunteers using CHESS after placing a polyurethane sponge pillow, rice pad, or flour pad in the popliteal space under the flexed knee. We visually assessed the number of areas with lingering fat signals and the statistical differences among the groups were assessed using Tukey's test.Results: Similarly to rice, flour clearly decreased lingering fat signals in the phantom study. A similar effect was obtained in the off-center images. In the volunteer study, the mean number of areas with lingering fat signals was 2.5 with a sponge pillow, 0.5 with the rice pad, and 0.3 with the flour pad. Those numbers were significantly different using flour pad and rice pad compared with sponge pillow (P < 0.001). No significant differences were seen between flour pads and rice pads (P = 0.662).Conclusion: Flour pads can suppress lingering fat signals in CHESS images.

Diffusion‐prepared neurography of the brachial plexus with a large field‐of‐view at 3T

“…The positive influence of pads filled with fluids or other materials to create a susceptibility‐matched volume around the neck has been reported previously . In our study pineapple juice was used because it has a low intensity on T 2 ‐weighted images, is widely available, cheap, and nontoxic.…”

“…However, the signal is still visible and is even relatively high in T 1 ‐weighted images with very short TE. Therefore, other fluids or materials such as deuterated water or fluorinated oils, which provide equally good susceptibility matching with no signal, might be preferred …”

“…For improved shimming a susceptibility‐matched pillow (referred to from here on as Pillow) around the neck to cope with air–tissue transitions was tested . Additionally, a relatively new and easy to use image‐based (IB) shimming method was used to homogenize B 0 and this was compared to standard shimming in a boxed volume (referred to from here on as Standard).…”