Purpose: Voxel-based quantification (VBQ) smoothing is a technique used to smooth quantitative parametric maps in the Montreal Neurological Institute standard space. Although VBQ smoothing could suppress changes in quantitative values at tissue boundaries, its effectiveness on relaxation time (T₁ and T₂ values and proton density PD) maps has not been investigated. The purpose of this study was to clarify the usefulness of VBQ smoothing in relaxation time mapping. Method: T₁ and T₂ values and PD maps of the brains of 20 healthy participants were obtained using a two-dimensional multi-dynamic multi-echo sequence. VBQ and Gaussian smoothing were applied to the relaxation time maps by varying the kernel size by 1 mm from 1 to 6 mm. Changes in relaxation time before and after VBQ and Gaussian smoothing for the putamen, caudate nucleus, substantia nigra, and corpus callosum on the relaxation time maps were evaluated. Result: The changes in relaxation time after VBQ smoothing application were smaller than those in that after Gaussian smoothing application. Although the differences in the relaxation time for all tissues before and after VBQ and Gaussian smoothing applications increased with increasing kernel size for all relaxation times for both methods, the changes in the relaxation time for VBQ smoothing were smaller than those in that for Gaussian smoothing. Conclusion: VBQ smoothing can suppress the change in the relaxation time on the boundary of the tissue and is thus a useful smoothing technique in relaxation time mapping.

Readout-segmented echo-planar imaging (readout segmentation of long variable echo trains [RESOLVE]) can be set to higher resolution than single-shot echo planar imaging, but there is concern that the signal-to-noise ratio (SNR) is low. The purpose was to examine the effect of imaging parameters (repetition time: TR, number of excitations: NEX) for RESOLVE on SNR and apparent diffusion coefficient (ADC) value in 1.5 T MRI, assuming a prostate examination. We imaged eight healthy male volunteers at a b value of 800 s/mm². SNR and ADC value were calculated by setting the ROI in the transition zone (TZ) and the peripheral zone (PZ) of the prostate. Then, 3 radiologists visually evaluated the graininess. In TZ, there was no significant difference in SNR with changing TR. In PZ, SNR increased with increasing TR. In PZ, median SNR was 8.1 [6.9–9.3] at TR=11000 ms and NEX=2. On the other hand, at TR=5000 ms and NEX=3,4, median SNRs were 8.5 [7.5–9.3] and 9.8 [8.8–11.2]. Moreover, NEX=5 with median SNR of 11.1 [10.7–11.7] was significant (p<0.008). Setting more NEX was more effective in increasing SNR. In addition, visual evaluation showed similar results. The ADC value in TZ was around 1404×10⁻⁶ mm²/s, and the ADC value in PZ was around 1469×10⁻⁶ mm²/s. There were no significant differences under each condition. In conclusion, NEX is more effective than TR for improving SNR both quantitatively and visually in PZ.

The purpose of this study was to evaluate the effectiveness of a hands-on seminar using a Web conferencing system, based on the post-event questionnaires of the face-to-face and online seminars of the hands-on seminar. For participants to feel realistic training in the online seminars, four educational videos explaining the procedure of the practical skill were created. We compared results of questionnaires acquired from participants after the face-to-face and online seminars. The questions about expectation, comprehension, satisfaction level, and lecture time for the seminars were graded on a 5-point scale. The higher the scores, the higher the rating, except for lecture time. A score of 3 was appropriate for the lecture time, with a higher score indicating that the seminar felt longer and a lower score indicating that the seminar felt shorter. In the evaluation of classroom lectures, such as expectation, comprehension, and satisfaction level for the seminars, there were no significant differences between the face-to-face and online seminars, and both achieved high scores of 4 or more. There was a significant difference in the evaluation of lecture time for classroom lectures, with participants feeling that it was too short in the face-to-face but just right in the online. In all evaluations for hands-on training and discussion, there were no significant differences between the face-to-face and online seminars, and both achieved high scores of 4 or more and time was short. It was concluded that our proposed online seminar approach could achieve a high level of evaluation as face-to-face seminars.