Micro-CT observation of test food materials for videofluoroscopic swallowing studies

Objectives

We examined the usefulness of micro-computed tomography (micro-CT) to measure the distributions of contrast media in materials that simulated the properties of test foods for videofluoroscopic (VF) swallowing studies (VFSS).

Methods

Food samples that simulated rice, rice gruel, custard pudding, udon noodles, and liquids were prepared with barium sulfate and iodine contrast media. These samples and simulated foods containing no contrast medium were subjected to micro-CT. The micro-CT scanning was performed using a ScanXmate-RB090SS. Each sample was used to fill a cylindrical container with an inner diameter of 8 mm and a height of 35 mm or a 1-mL plastic syringe, and images were acquired at a voltage of 90 kV, current of 45 μA, and magnification power of 2.5. From the acquired data, 610 × 610-pixel 8-bit image slices were prepared and observed using OsiriX software. The image densities (pixel values) were measured for regions of interest. The obtained pixel values were then normalized on the basis of the density of the barium sulfate contrast medium and water.

Results

The infiltration or distributions of the contrast media in the VF test materials were successfully observed, and their values ranged widely compared with the barium sulfate contrast medium.

Conclusions

Micro-CT imaging was capable of numerically presenting or visualizing the density and distribution of VF test materials, thereby showing its usefulness as an objective evaluation method. Using this technique, it may be possible to adjust test foods to the optimum contrast properties for clinical VF examinations.