[Detectability of High Intensity Areas in FLAIR and Multi Shot EPI-FLAIR: Phantom Study].

In magnetic resonance imaging (MRI) of brain, fast spin echo-fluid attenuated inversion recovery (FSE-FLAIR) is widely used to detect high intensity areas (HIAs). The way of getting FLAIR contrast at high speed includes echo planar imaging-FLAIR (EPI-FLAIR), and in EPI-FLAIR there are single shot EPI-FLAIR (SS-EPI-FLAIR) and multi shot EPI-FLAIR (MS-EPI-FLAIR). There were negative opinions for the reports of SS-EPI-FLAIR, and it is reported that SS-EPI-FLAIR is able to acquire image quality that is equal to FSE-FLAIR in a shorter time, recently. But there are few reports that utilized contrast of MS-EPI-FLAIR. Our object was to compare HIA detectability in FSE-FLAIR and MS-EPI-FLAIR in equal imaging time, and to evaluate a basic characteristic. We dissolved indigestive dextrin in the aqua destillata and created a 0-46 wt% phantom. The concentration that correspond to T1, T2 value of brain white matter was 42 wt%. We calculated contrast by using signal intensities of each phantom, and compared contrast by signal intensities of each phantom, and compared the contrast of MS-EPI-FLAIR and FSE-FLAIR. In the range of 18-46 wt%, the contrast of MS-EPI-FLAIR was positive value, and that of FSE-FLAIR was 26-42 wt%. By the statistical test, contrast of MS-EPI-FLAIR in 18-26% was significantly different for FSE-FLAIR. In conclusion, it was suggestive that MS-EPI-FLAIR is able to detect HIA equally or sharply.

Aberrant resting-state functional connectivity of major depressive disorder with higher risk of suicide.

Aim: Suicide prevention for depressive patients is an important clinical issue in psychiatry. However, not all depressive patients plan or attempt suicide. In this study, we investigated the differences of functional brain networks between a high-risk group and a low-risk group for suicide by comparing resting-state functional connectivity (rsFC). Methods: The subjects were 29 patients with major depressive disorder, nine of whom had attempted suicide. The suicidal ideation of all subjects was assessed with the Columbia-Suicide Severity Rating Scale, then the subjects were divided into two groups based on the most severe suicidal ideation (MSI) in their lifetime. We compared rsFC between the two groups. Results: Of the 29 subjects, 16 were in the severe MSI group. We found that the severe MSI group members had significantly smaller rsFC in two networks: one comprised the right dorsolateral prefrontal cortex and the default-mode network, and the other comprised the left rostrolateral prefrontal cortex and the striatum, amygdala, and hippocampus. These regions are reported to be associated with rumination, retrieval suppression, and delay discounting (DD). Conclusion: Our results suggest that functional networks related to rumination, retrieval suppression, and DD might be impaired in depressive patients with severe suicidal ideation. It might be beneficial for psychiatrists to assess these characteristics in terms of suicide prevention for depressive patients.