Blunted diurnal interleukin-6 rhythm is associated with amygdala emotional hyporeactivity and depression: a modulating role of gene-stressor interactions.

Background: The immune system has major roles in the brain and related psychopathology. Disrupted interleukin-6 secretion and aberrant amygdala emotional reactivity are well-documented in stress-related mental disorders. The amygdala regulates psychosocial stress-related interleukin-6 affected by related genes. These led us to comprehensively examine the relationship between interleukin-6, amygdala activity, and stress-related mental symptoms under gene-stressor interactions. Methods: One hundred eight nonclinical participants with various levels of anxiety/depression underwent magnetic resonance imaging scans during an emotional face task for amygdala activity and saliva collection (at 10-time points across 2 days) for the total output and diurnal patterns of interleukin-6. Gene-stressor interactions between rs1800796 (C/G) and rs2228145 (C/A) and stressful life events for the biobehavioral measures were explored. Results: The blunting of interleukin-6 diurnal pattern was associated with hypoactivation of the basolateral amygdala in response to fearful (vs. neutral) faces (t = 3.67, FWE-corrected p = 0.003), and was predominantly observed in individuals with rs1800796 C-allele homozygotes and negative life changes in the past year (F = 19.71, p < 0.001). When considered in a comprehensive model, the diminished diurnal pattern predicted greater depressive symptoms (ß = -0.40), modulated by the amygdala hypoactivity (ß = 0.36) and rs1800796-stressor interactions (ß = -0.41; all p < 0.001). Conclusion: Here we show that the blunted interleukin-6 diurnal rhythm predicts depressive symptoms, modulated by amygdala emotional hyporeactivity and gene-stressor interactions. These findings indicate a potential mechanism underlying vulnerability to depressive disorders, suggesting their early detection, prevention, and treatment through the understanding of immune system dysregulation.

Verification of dose distribution in high dose-rate brachytherapy for cervical cancer using a normoxic N-vinylpyrrolidone polymer gel dosimeter.

The polymer gel dosimeter has been proposed for use as a 3D dosimeter for complex dose distribution measurement of high dose-rate (HDR) brachytherapy. However, various shapes of catheter/applicator for sealed radioactive source transport used in clinical cases must be placed in the gel sample. The absorbed dose readout for the magnetic resonance (MR)-based polymer gel dosimeters requires calibration data for the dose-transverse relaxation rate (R2) response. In this study, we evaluated in detail the dose uncertainty and dose resolution of three calibration methods, the multi-sample and distance methods using the Ir-192 source and the linear accelerator (linac) method using 6MV X-rays. The use of Ir-192 sources increases dose uncertainty with steep dose gradients. We clarified that the uniformly irradiated gel sample improved the signal-to-noise ratio (SNR) due to the large slice thickness of MR images and could acquire an accurate calibration curve using the linac method. The curved tandem and ovoid applicator used for intracavitary irradiation of HDR brachytherapy for cervical cancer were reproduced with a glass tube to verify the dose distribution. The results of comparison with the treatment planning system (TPS) calculation by gamma analysis on the 3%/2 mm criterion were in good agreement with a gamma pass rate of 90%. In addition, the prescription dose could be evaluated accurately. We conclude that it is easy to place catheter/applicator in the polymer gel dosimeters, making them a useful tool for verifying the 3D dose distribution of HDR brachytherapy with accurate calibration methods.

Association of childhood maltreatment history with salivary interleukin-6 diurnal patterns and C-reactive protein in healthy adults.

Childhood maltreatment has been associated with increased inflammation, as indicated by elevated levels of proinflammatory markers such as interleukin-6 (IL-6) and C-reactive protein (CRP). Studies in humans show that secretion of IL-6 follows a clear circadian rhythm, implying that its disturbed rhythm represents an important aspect of dysregulated inflammatory system. However, possible alterations in diurnal secretion patterns of IL-6 associated with childhood maltreatment have not been studied. Here we investigated this association in 116 healthy adults. Diurnal levels of IL-6 were examined using saliva samples collected at 5 times a day across 2 consecutive days. Salivary CRP levels were also determined by averaging measurements at 2 times a day for 2 days. Different types of childhood maltreatment were assessed with the Childhood Trauma Questionnaire (CTQ). CTQ total and emotional abuse scores were significantly correlated with smaller IL-6 diurnal variation as indexed by lower standard deviation across the measurement times (p = 0.024 and p = 0.008, respectively). Individuals with emotional abuse, as defined by a cut-off score of CTQ, showed flatter IL-6 rhythm than those without (p = 0.031). These results, both correlation and group comparison, remained significant after controlling for age, sex, and body mass index. Childhood maltreatment was not associated with total output of IL-6 or CRP. Our findings indicate that childhood trauma can have a long-term negative effect on the circadian rhythm of inflammatory system. The findings are consistent with those of previous studies on adulthood trauma, suggesting that the disrupted IL-6 rhythmicity may be associated with a broad range of trauma-related conditions.

Implicit and explicit emotional memory recall in anxiety and depression: Role of basolateral amygdala and cortisol-norepinephrine interaction.

Anxiety and depression are linked to both explicit and implicit memory biases, which are defined as the tendency to preferentially recall emotionally negative information at conscious and subconscious levels, respectively. Functional connectivity (FC) of the basolateral amygdala (BLA) and related stress hormones (i.e., cortisol and norepinephrine) are purportedly implicated in these biases. However, previous findings on memory biases in anxiety and depression have been inconsistent, likely due to their symptomatic complications. Therefore, the underlying neurobiological mechanism remains unclear. We thus investigated whether anxiety and depression as premorbid predispositions are related to the memory biases, and whether FC of BLA, cortisol, and 3-methoxy-4-hydroxyphenylglycol (MHPG: a major metabolite of norepinephrine) would affect the anxiety/depression-related biased memory recall in 100 participants without psychiatric symptomatology. Psycho-behavioral assessment, resting-state fMRI scans, and saliva collection at 10-points-in-time across two days were conducted. Correlations of memory biases with anxiety/depression and neurobiological markers were explored. As a result, neither anxiety nor depression were correlated with explicit memory bias to negative (vs. positive) information, although depression was associated with better recall of the negative stimuli only when they were perceived as self-relevant. In contrast, both anxiety and depression were correlated with implicit memory bias; however, the effects were solely explained by anxiety. Furthermore, FC of the BLA with subgenual anterior cingulate cortex (sgACC) and the synergetic effect of cortisol and MHPG uniquely affected the implicit memory bias. These findings suggest that anxiety facilitates an initial snapshot of negative information and can be accompanied by depression when the information creates negative semantic associations with the self. The BLA-sgACC neural connectivity and cortisol-norepinephrine interaction that are associated with the implicit memory bias might be one of the important neurobiological targets in the prevention and treatment for comorbid anxiety and depressive disorders.

Whole Three-Dimensional Dosimetry of Carbon Ion Beams with an MRI-Based Nanocomposite Fricke Gel Dosimeter Using Rapid T1 Mapping Method.

MRI-based gel dosimeters are attractive systems for the evaluation of complex dose distributions in radiotherapy. In particular, the nanocomposite Fricke gel dosimeter is one among a few dosimeters capable of accurately evaluating the dose distribution of heavy ion beams. In contrast, reduction of the scanning time is a challenging issue for the acquisition of three-dimensional volume data. In this study, we investigated a three-dimensional dose distribution measurement method for heavy ion beams using variable flip angle (VFA), which is expected to significantly reduce the MRI scanning time. Our findings clarified that the whole three-dimensional dose distribution could be evaluated within the conventional imaging time (20 min) and quality of one cross-section.

Usefulness of a Metal Artifact Reduction Algorithm in Digital Tomosynthesis Using a Combination of Hybrid Generative Adversarial Networks.

In this study, a novel combination of hybrid generative adversarial networks (GANs) comprising cycle-consistent GAN, pix2pix, and (mask pyramid network) MPN (CGpM-metal artifact reduction [MAR]), was developed using projection data to reduce metal artifacts and the radiation dose during digital tomosynthesis. The CGpM-MAR algorithm was compared with the conventional filtered back projection (FBP) without MAR, FBP with MAR, and convolutional neural network MAR. The MAR rates were compared using the artifact index (AI) and Gumbel distribution of the largest variation analysis using a prosthesis phantom at various radiation doses. The novel CGpM-MAR yielded an adequately effective overall performance in terms of AI. The resulting images yielded good results independently of the type of metal used in the prosthesis phantom (p < 0.05) and good artifact removal at 55% radiation-dose reduction. Furthermore, the CGpM-MAR represented the minimum in the model with the largest variation at 55% radiation-dose reduction. Regarding the AI and Gumbel distribution analysis, the novel CGpM-MAR yielded superior MAR when compared with the conventional reconstruction algorithms with and without MAR at 55% radiation-dose reduction and presented features most similar to the reference FBP. CGpM-MAR presents a promising method for metal artifact and radiation-dose reduction in clinical practice.

Childhood trauma affects autobiographical memory deficits through basal cortisol and prefrontal-extrastriate functional connectivity.

BACKGROUND: Psychological trauma can damage the brain, especially in areas where glucocorticoid receptors are expressed, via perturbed secretion of cortisol. Childhood trauma is associated with blunted basal cortisol secretion, brain alterations, and autobiographical memory deficits referred to as overgeneral autobiographical memory (OGM). However, it remains unknown whether childhood trauma affects OGM through altered cortisol and brain alterations. METHODS: Using resting-state fMRI in 100 healthy humans, we examined whether childhood trauma affects OGM through its related basal cortisol and brain functional connectivity (FC). Trauma and OGM were assessed using the Childhood Trauma Questionnaire (CTQ) and Autobiographical Memory Test (AMT), respectively. Basal cortisol levels were measured by 10 points-in-time across two days. Multiple mediation analysis was employed. RESULTS: CTQ was associated with greater semantic-associate memory of OGM, a retrieval tendency toward semantic content with no specific contextual details of an experienced event, as well as blunted basal cortisol levels. While CTQ was correlated with decreased FC between the hippocampus and medial prefrontal cortex (PFC), it showed a more predominant correlation with increased FC between the lateral and anteromedial PFC and extrastriate cortex. Importantly, the increased prefrontal-extrastriate FC completely mediated the relationship between CTQ and semantic-associate memory, affected by hyposecretion of cortisol. CONCLUSION: Childhood trauma may lead to the lack of visuoperceptual contextual details in autobiographical memory by altering basal cortisol secretion and connectivity of the prefrontal-hippocampal-extrastriate regions. The intensified prefrontal-extrastriate connectivity may contribute to OGM formation by strengthening the semantic content in memory retrieval. Understanding the mechanisms underlying the trauma-cortisol-brain-memory link will provide important clinical implications for trauma-related mental disorders.

Improved digital chest tomosynthesis image quality by use of a projection-based dual-energy virtual monochromatic convolutional neural network with super resolution.

We developed a novel dual-energy (DE) virtual monochromatic (VM) very-deep super-resolution (VDSR) method with an unsharp masking reconstruction algorithm (DE-VM-VDSR) that uses projection data to improve the nodule contrast and reduce ripple artifacts during chest digital tomosynthesis (DT). For estimating the residual errors from high-resolution and multiscale VM images from the projection space, the DE-VM-VDSR algorithm employs a training network (mini-batch stochastic gradient-descent algorithm with momentum) and a hybrid super-resolution (SR) image [simultaneous algebraic reconstruction technique (SART) total-variation (TV) first-iterative shrinkage-thresholding algorithm (FISTA); SART-TV-FISTA] that involves subjective reconstruction with bilateral filtering (BF) [DE-VM-VDSR with BF]. DE-DT imaging was accomplished by pulsed X-ray exposures rapidly switched between low (60 kV, 37 projection) and high (120 kV, 37 projection) tube-potential kVp by employing a 40° swing angle. This was followed by comparison of images obtained employing the conventional polychromatic filtered backprojection (FBP), SART, SART-TV-FISTA, and DE-VM-SART-TV-FISTA algorithms. The improvements in contrast, ripple artifacts, and resolution were compared using the signal-difference-to-noise ratio (SDNR), Gumbel distribution of the largest variations, radial modulation transfer function (radial MTF) for a chest phantom with simulated ground-glass opacity (GGO) nodules, and noise power spectrum (NPS) for uniform water phantom. The novel DE-VM-VDSR with BF improved the overall performance in terms of SDNR (DE-VM-VDSR with BF: 0.1603, without BF: 0.1517; FBP: 0.0521; SART: 0.0645; SART-TV-FISTA: 0.0984; and DE-VM-SART-TV-FISTA: 0.1004), obtained a Gumbel distribution that yielded good images showing the type of simulated GGO nodules used in the chest phantom, and reduced the ripple artifacts. The NPS of DE-VM-VDSR with BF showed the lowest noise characteristics in the high-frequency region (~0.8 cycles/mm). The DE-VM-VDSR without BF yielded an improved resolution relative to that of the conventional reconstruction algorithms for radial MTF analysis (0.2-0.3 cycles/mm). Finally, based on the overall image quality, DE-VM-VDSR with BF improved the contrast and reduced the high-frequency ripple artifacts and noise.

Verification of dose distribution in high-dose-rate brachytherapy using a nanoclay-based radio-fluorogenic gel dosimeter.

Dose distributions have become more complex with the introduction of image-guided brachytherapy in high-dose-rate (HDR) brachytherapy treatments. Therefore, to correctly execute HDR, conducting a quality assurance programme for the remote after-loading system and verifying the dose distribution in the patient treatment plan are necessary. The characteristics of the dose distribution of HDR brachytherapy are that the dose is high near the source and rapidly drops when the distance from the source increases. Therefore, a measurement tool corresponding to the characteristic is required. In this study, using an Iridium-192 (Ir-192) source, we evaluated the basic characteristics of a nanoclay-based radio-fluorogenic gel (NC-RFG) dosimeter that is a fluorescent gel dosimeter using dihydrorhodamine 123 hydrochloride as a fluorescent probe. The two-dimensional dose distribution measurements were performed at multiple source positions to simulate a clinical plan. Fluorescence images of the irradiated NC-RFG were obtained at a high resolution (0.04 mm pixel-1) using a gel scanner with excitation at 465 nm. Good linearity was confirmed up to a dose range of 100 Gy without dose rate dependence. The dose distribution measurement at the five-point source position showed good agreement with the treatment planning system calculation. The pass ratio by gamma analysis was 92.1% with a 2%/1 mm criterion. The NC-RFG dosimeter demonstrates to have the potential of being a useful tool for quality assurance of the dose distribution delivered by HDR brachytherapy. Moreover, compared with conventional gel dosimeters such as polymer gel and Fricke gel dosimeters it solves the problems of diffusion, dose rate dependence and inhibition of oxygen-induced reactions. Furthermore, it facilitates dose data to be read in a short time after irradiation, which is useful for clinical use.

End-to-end delivery quality assurance of computed tomography-based high-dose-rate brachytherapy using a gel dosimeter.

PURPOSE: The purpose of this study was to develop a novel quality assurance (QA) program to check the entire treatment chain of image-guided brachytherapy with dose distribution evaluation in a single setup and irradiation using a gel dosimeter. METHODS AND MATERIALS: A polymer gel was used, and the readout was performed by magnetic resonance scanning. A CT-based treatment plan was generated using the Oncentra planning system (Elekta, Sweden), and irradiation was performed three times using an afterloading device with an Ir-192 source. The dose-response curve of the gel was created using 6-MV X-ray, which is independent of the source beams. Planar gamma images on a coronal plane along the source transport axis were calculated using the measured dose as a reference, and the calculated doses were used in several error simulations (no error; 2.0 or 2.5 mm systematic and random source dwell mispositioning; and dose error of 2%, 5%, 10%, and 20%). RESULTS: The dose-R2 (spin-spin relaxation rate) conversion table revealed that the uncertainty and dose resolution of 6-MV X-ray were better than those of Ir-192 and also constant between the three measurements. With the 3%/1 mm criteria, there were statistically significant differences between each pair of settings except dose error of 2% and 5%. CONCLUSION: This work depicts a simple and efficient end-to-end test that can provide a clinically useful tool for QA of image-guided brachytherapy. In this QA program, air kerma strength and dwell position setting could also be verified. This test can also distinguish between different types of error.

Basolateral Amygdala Connectivity With Subgenual Anterior Cingulate Cortex Represents Enhanced Fear-Related Memory Encoding in Anxious Humans.

BACKGROUND: The amygdala can enhance emotional memory encoding as well as anxiogenesis via corticotropin-releasing factor neurons. However, the amygdala's explicit role in emotional encoding remains unclarified in humans. We examined how functional connectivity (FC) of amygdala subnuclei affects emotional encoding, considering its mechanism in which anxiety, attention, and cortisol conceivably participate. METHODS: A total of 65 healthy humans underwent resting-state functional magnetic resonance imaging scans and saliva collection at 10 points in time over 2 days. FC analysis was performed for basolateral amygdala subnucleus (BLA) and centromedial amygdala subnucleus. We assessed attentional control via an emotional Stroop task and assessed emotional encoding via a facial identification task that examines how strongly a neutral face is memorized when accompanied by an emotional face (fearful, sad, or happy). FC and task performance were compared between high-anxious and non-high-anxious groups classified by anxious personality scores. RESULTS: BLA connected with subgenual anterior cingulate cortex (sgACC) in proportion to the strength of fear-related encoding, whereas centromedial subnucleus connected with caudate nucleus for happy-related encoding. The high-anxious group showed more enhanced fear-related encoding but impaired happy-related encoding compared with the non-high-anxious group. BLA-sgACC FC was more intensified in the high-anxious group than in the non-high-anxious group; however, centromedial-caudate FC did not differ between them. Although emotional encoding was uncorrelated with either attentional control or cortisol, BLA-sgACC was positively correlated with cortisol increase after awakening. CONCLUSIONS: The study revealed that neural interactions of BLA, specifically with sgACC, might play a critical role in fear-related memory encoding, depending on the individual's level of anxiety. These findings aid in understanding the complicated mechanisms of emotional memory in anxiety disorders.

Sensitivity enhancement of DHR123 radio-fluorogenic nanoclay gel dosimeter by incorporating surfactants and halogenides.

Dosimetry of spatial dose distribution of ionizing radiation in tissue equivalent materials is particularly important for cancer radiotherapy. Here, we describe a radio-fluorogenic gel-based dosimeter that has achieved 16 times higher sensitivity by incorporating surfactants and halogenides. The gel dosimeters were prepared from dihydrorhodamine 123 (DHR123) and small amounts of nano-sized clay and a radiosensitizer. By comprehensively changing the type of additives for the sensitizer (three surfactants: Triton X-100, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide, and three halogenides: trichloroacetic acid, tribromoacetic acid and 2,2,2-trichloroethanol), the increase in sensitivity can be explained by an increase in relative fluorescence quantum yield and an increase in radiation chemical yield. These highly sensitive gel dosimeters also show dose rate independent sensitivity under irradiation at 0.64 and 0.77 Gy min-1 using a 6 MV X-ray therapeutic beam from the medical linac.

Development of a denoising convolutional neural network-based algorithm for metal artifact reduction in digital tomosynthesis for arthroplasty: A phantom study.

The present study aimed to develop a denoising convolutional neural network metal artifact reduction hybrid reconstruction (DnCNN-MARHR) algorithm for decreasing metal objects in digital tomosynthesis (DT) for arthroplasty by using projection data. For metal artifact reduction (MAR), we implemented a DnCNN-MARHR algorithm based on a training network (mini-batch stochastic gradient descent algorithm with momentum) to estimate the residual reference (140 keV virtual monochromatic [VM]) and object (70 kV with metal artifacts) images. For this, we used projection data and subtracted the estimated residual images from the object images, involving hybrid and subjectively reconstructed image usage (back projection and maximum likelihood expectation maximization [MLEM]). The DnCNN-MARHR algorithm was compared with the dual-energy material decomposition reconstruction algorithm (DEMDRA), VM, MLEM, established and commonly used filtered back projection (FBP), and a simultaneous algebraic reconstruction technique-total variation (SART-TV) with MAR processing. MAR was compared using artifact index (AI) and texture analysis. Artifact spread functions (ASFs) for images that were out-of-plane and in-focus were evaluated using a prosthesis phantom. The overall performance of the DnCNN-MARHR algorithm was adequate with regard to the ASF, and the derived images showed better results, without being influenced by the metal type (AI was almost equal to the best value for the DEMDRA). In the ASF analysis, the DnCNN-MARHR algorithm generated better MAR compared with that obtained employing usual algorithms for reconstruction using MAR processing. In addition, comparison of the difference (mean square error) between DnCNN-MARHR and the conventional algorithm resulted in the smallest VM. The DnCNN-MARHR algorithm showed the best performance with regard to image homogeneity in the texture analysis. The proposed algorithm is particularly useful for reducing artifacts in the longitudinal direction, and it is not affected by tissue misclassification.

Cortisol-related hippocampal-extrastriate functional connectivity explains the adverse effect of cortisol on visuospatial retrieval.

Cortisol is known to affect visuospatial memory through its major binding site in the brain, the hippocampus. The synchronization of neural activity between the hippocampus, prefrontal cortex (PFC), and visual cortex is presumed to be essential for the formation of visuospatial memory because of their visuospatial learning-dependent neuroplasticity. However, it remains unclear how hippocampal connectivity with the PFC and visual cortex is involved in the relationship between cortisol and visuospatial memory in humans. We thus investigated whether functional connectivity (FC) of the hippocampus, specifically its rostral and caudal subdivisions, mediates the relationship between visuospatial memory and endogenous cortisol. One-hundred sixty-six healthy young adults underwent standard neuropsychological tests to assess visuospatial construction (a complex figure copying test) and retrieval (the corresponding recall test) and collected their saliva at 6-time points across 2 consecutive days for measurement of daily cortisol concentrations (dCOR). Ninety of them received resting-state fMRI scans. Greater dCOR was significantly associated with better figure copying performance, but contrastingly with poorer figure recall. In proportion to dCOR, the rostral hippocampus (rHC) showed significantly increased FC with the PFC (including its dorsolateral and medial parts) and the inferior lateral occipital cortex (iLOC), while the caudal hippocampus had increased FC with the anterior middle temporal cortex. Of the cortisol-related hippocampal connectivity, the rHC-iLOC FC was specifically correlated with figure recall and showed complete mediation for the negative relationship of dCOR with figure recall. These results suggest that cortisol might have enhancing effects on visuospatial encoding as well as impairing effects on visuospatial retrieval, possibly due to its occupancy patterns of corticosteroid receptors. Cortisol's adverse effects on visuospatial retrieval might be explained through cortisol-related rostral hippocampal connectivity with the iLOC, which is a part of the extrastriate cortex implicated in visuospatial perception. Thorough dissection of hippocampal-prefrontal-extrastriate connectivity might facilitate the understanding of neural mechanisms underlying cortisol's contrasting effects on encoding (or consolidation) and retrieval of visuospatial information.

Dose distribution verification in high-dose-rate brachytherapy using a highly sensitive normoxic N-vinylpyrrolidone polymer gel dosimeter.

Rapid technological advances in high-dose-rate brachytherapy have led to a requirement for greater accuracy in treatment planning system calculations and in the verification of dose distributions. In high-dose-rate brachytherapy, it is important to measure the dose distribution in the low-dose region at a position away from the source in addition to the high-dose range in the proximity of the source. The aim of this study was to investigate the accuracy of a treatment plan designed for prostate cancer in the low-dose range using a normoxic N-vinylpyrrolidone-based polymer gel (VIPET gel) dosimeter containing inorganic salt as a sensitizer (iVIPET). The dose response was evaluated on the basis of the transverse relaxation rate (R2) measured by magnetic resonance scanning. In the verification of the treatment plan, gamma analysis showed that the dose distributions obtained from the polymer gel dosimeter were in good agreement with those calculated by the treatment planning system. The gamma passing rate according to the 2%/2 mm criterion was 97.9%. The iVIPET gel dosimeter provided better accuracy for low doses than the normal VIPET gel dosimeter, demonstrating the potential to be a useful tool for quality assurance of the dose distribution delivered by high-dose-rate brachytherapy.

Attentional bias modification alters intrinsic functional network of attentional control: A randomized controlled trial.

INTRODUCTION: Attentional bias modification (ABM) alleviates anxiety by moderating biased attentional processing toward threat; however, its neural mechanisms remain unclear. We examined how ABM changes functional connectivity (FC) and functional network measures, leading to anxiety reduction. METHODS: Fifty-four healthy anxious individuals received either ABM or sham training for 1 month in a double-blind randomized controlled trial. Anxious traits, attentional control, and attentional bias were assessed. Thirty-five participants completed resting-state functional magnetic resonance imaging (MRI) scans before and after training. RESULTS: ABM significantly mitigated an anxious traits regarding physical stress vulnerability (η2 = 0.12, p = 0.009). As compared to sham training, ABM significantly strengthened FC between the pulvinar and transverse temporal gyrus along the temporoparietal junction (T = 3.90, FDR-correctedp = 0.010), whereas it decreased FC between the postCG and ventral fronto-parietal network (vFPN) regions such as the anterior insula and ventrolateral prefrontal cortex (all T ≤ - 3.19, FDR-correctedp ≤ 0.034). Although ABM diminished network measures of the postcentral gyrus (postCG) (all T ≤ - 4.30, FDR-correctedp ≤ 0.006), only the pulvinar-related FC increase was specifically correlated with anxiety reduction (r = - 0.46, p = 0.007). LIMITATIONS: Per-protocol analysis and reduced sample size in MRI analysis. CONCLUSIONS: ABM might augment the pulvinar's control over vFPN to maintain endogenous attention to a behavioral goal, while diminishing the information exchanges of the postCG with vFPN to inhibit the capture of exogenous attention by potential threats. The pulvinar might play a critical role in ABM anxiolytic efficacy.

Amygdala-centred functional connectivity affects daily cortisol concentrations: a putative link with anxiety.

The amygdala plays a critical role in emotion. Its functional coupling with the hippocampus and ventromedial prefrontal cortex extending to a portion of the anterior cingulate cortex (ACC) is implicated in anxiogenesis and hypothalamic-pituitary-adrenal (HPA) system regulation. However, it remains unclear how amygdala-centred functional connectivity (FC) affects anxiety and cortisol concentrations in everyday life. Here, we investigate the relationship between daily cortisol concentrations (dCOR) and amygdala-centred FC during emotional processing in forty-one healthy humans. FC analyses revealed that higher dCOR predicted strengthened amygdala-centred FC with the hippocampus and cerebellum, but inhibited FC with the supramarginal gyrus and a perigenual part of the ACC (pgACC) when processing fearful faces (vs. neutral faces). Notably, the strength of amygdala-hippocampus FC mediated the positive relationship between cortisol and anxiety, specifically when the effect of amygdala-pgACC FC, a presumptive neural indicator of emotional control, was taken into account. Individuals with diminished connectivity between the amygdala and pgACC during fear-related processing might be more vulnerable to anxiogenesis as it pertains to greater circulating cortisol levels in everyday life. Individual functional patterns of amygdala-hippocampal-pgACC connectivity might provide a key to understand the complicate link between cortisol and anxiety-related behaviors.

[Polymer Gel Dosimetry for the High-Dose-Rate Brachytherapy Using Ir-192 Source].

High-dose-rate (HDR) brachytherapy is performed with the remote after-loading system (RALS) to transport an Ir-192 source directly to inside or near the tumor. Quality assurance (QA) of equipment should be performed at sufficient frequency to ensuring safety and quality of HDR brachytherapy treatment. Polymer gel dosimeters have been attracting attention in recent years as a QA tools of HDR brachytherapy, because they can measure the three-dimensional steep dose gradients around HDR sources. In this paper, we introduce our preliminary results using VIPET polymer gel dosimeters for Ir-192 HDR brachytherapy dosimetry.

Repeatability of Brain Volume Measurements Made with the Atlas-based Method from T1-weighted Images Acquired Using a 0.4 Tesla Low Field MR Scanner.

PURPOSE: An understanding of the repeatability of measured results is important for both the atlas-based and voxel-based morphometry (VBM) methods of magnetic resonance (MR) brain volumetry. However, many recent studies that have investigated the repeatability of brain volume measurements have been performed using static magnetic fields of 1-4 tesla, and no study has used a low-strength static magnetic field. The aim of this study was to investigate the repeatability of measured volumes using the atlas-based method and a low-strength static magnetic field (0.4 tesla). MATERIALS AND METHODS: Ten healthy volunteers participated in this study. Using a 0.4 tesla magnetic resonance imaging (MRI) scanner and a quadrature head coil, three-dimensional T1-weighted images (3D-T1WIs) were obtained from each subject, twice on the same day. VBM8 software was used to construct segmented normalized images [gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) images]. The regions-of-interest (ROIs) of GM, WM, CSF, hippocampus (HC), orbital gyrus (OG), and cerebellum posterior lobe (CPL) were generated using WFU PickAtlas. The percentage change was defined as[100 × (measured volume with first segmented image - mean volume in each subject)/(mean volume in each subject)]The average percentage change was calculated as the percentage change in the 6 ROIs of the 10 subjects. RESULTS: The mean of the average percentage changes for each ROI was as follows: GM, 0.556%; WM, 0.324%; CSF, 0.573%; HC, 0.645%; OG, 1.74%; and CPL, 0.471%. The average percentage change was higher for the orbital gyrus than for the other ROIs. CONCLUSION: We consider that repeatability of the atlas-based method is similar between 0.4 and 1.5 tesla MR scanners. To our knowledge, this is the first report to show that the level of repeatability with a 0.4 tesla MR scanner is adequate for the estimation of brain volume change by the atlas-based method.

Effect of Breath Holding on Spleen Volume Measured by Magnetic Resonance Imaging.

OBJECTIVE: Ultrasonographic studies have demonstrated transient reduction in spleen volume in relation to apnea diving. We measured spleen volume under various respiratory conditions by MR imaging to accurately determine the influence of ordinary breath holding on spleen volumetry. MATERIALS AND METHODS: Twelve healthy adult volunteers were examined. Contiguous MR images of the spleen were acquired during free breathing and during respiratory manipulations, including breath holding at the end of normal expiration, breath holding at deep inspiration, and the valsalva maneuver, and spleen volume was measured from each image set based on the sum-of-areas method. Acquisition during free breathing was performed with respiratory triggering. The duration of each respiratory manipulation was 30 s, and five sets of MR images were acquired serially during each manipulation. RESULTS: Baseline spleen volume before respiratory manipulation was 173.0 ± 79.7 mL, and the coefficient of variance for two baseline measures was 1.4% ± 1.6%, suggesting excellent repeatability. Spleen volume decreased significantly just after the commencement of respiratory manipulation, remained constant during the manipulation, and returned to the control value 2 min after the cessation of the manipulation, irrespective of manipulation type. The percentages of volume reduction were 10.2% ± 2.9%, 10.2% ± 3.5%, and 13.3% ± 5.7% during expiration breath holding, deep-inspiration breath holding, and the valsalva maneuver, respectively, and these values did not differ significantly. CONCLUSIONS: Spleen volume is reduced during short breath-hold apnea in healthy adults. Physiological responses of the spleen to respiratory manipulations should be considered in the measurement and interpretation of spleen volume.