[Usefulness of Breath-hold DWI Focused on the Hepatic Dome in EOB-MRI].

PURPOSE: Respiratory-triggered-diffusion-weighted imaging (R-DWI) of the liver often results in poor image quality under the diaphragmatic dome on the cephalic side of the liver (hepatic dome) secondary to magnetic field inhomogeneity in liver magnetic resonance imaging (MRI). Hence, the usefulness of additional breath-hold-DWI (B-DWI) focusing on the hepatic dome was investigated. METHODS: A total of 22 patients (14 men and 8 women; mean age 69.0±11.7 years) who underwent ethoxybenzyl (EOB)-MRI at our hospital between July and August, 2022 using a 3.0 T MRI system were included. One radiologist and three radiology technologists visually assessed the visibility of R-DWI and B-DWI in the hepatic dome on a 4-point scale (1 to 4). Additionally, the apparent diffusion coefficient (ADC) values of the hepatic parenchyma on each DWI were compared. RESULTS: B-DWI improved visibility in the hepatic dome compared to R-DWI (2.67±0.71 vs. 3.25±0.43, p<0.05). No significant difference was found in the ADC values for each DWI. CONCLUSION: B-DWI has excellent visibility in the hepatic dome and is expected to complement R-DWI. Therefore, B-DWI is very useful as an additional imaging in EOB-MRI.

[Development of an magnetic resonance imaging safety management system for metallic biomedical products using an magnetic resonance compatibility database and inquiry-based patient records].

Several incidents involving magnetic resonance imaging (MRI) examinations of patients with unchecked MR-unsafe metallic products have been reported. To improve patient safety, we developed a new MRI safety management system for metallic biomedical products and evaluated its efficiency in clinical practice. Our system was integrated into the picture archiving and communication system (PACS) and comprised an MR compatibility database and inquiry-based patient records of internal metallic biomedical products, enabling hospital staff to check MR compatibility by product name. A total of 6,637 biomedical implants and devices were listed in this system, including product names and their MR compatibilities. Furthermore, MRI histories for each patient at our hospital were also recorded. Using this system, it was possible to confirm the MR compatibility of the patients' metallic biomedical products effectively and to reduce the number of unchecked internal products through systematic patient inquiry. In conclusion, our new system enhanced metallic biomedical product checking procedures, and improved patient safety during clinical MRI examinations.

[Measurement of slice thickness in magnetic resonance image by the impulse response].

The purpose of this study was to verify the applicability of measurement of slice thickness of magnetic resonance imaging (MRI) by the delta method, and to discuss the measurement precision by the disk diameter and baseline setup of the slice profile of the delta method. The delta method used the phantom which put in the disk made of acrylic plastic. The delta method measured the full width at half maximum (FWHM) and the full width at tenth maximum (FWTM) from the slice profile of the disk signal. Evaluation of the measurement precision of the delta method by the disk diameter and baseline setup were verified by comparison of the FWHM and FWTM. In addition, evaluation of the applicability of the delta method was verified by comparison of the FWHM and FWTM using the wedge method. The baseline setup had the proper signal intensity of an average of 10 slices in the disk images. There were statistically significant difference in the FWHM between disk diameter of 10 mm and disk diameter of 30 mm and 5 mm. The FWHM of the disk diameter of 10 mm was smaller than the disk diameter of 30 mm and 5 mm. There was no statistically significant difference in the FWHM between the delta method and the wedge method. There is no difference in the effective slice thickness of the delta method and the wedge method. The delta method has an advantage in measurement of thin slice thickness.