Improved visualization of intracranial distal arteries with multiple 2D slice dynamic ASL-MRA and super-resolution convolutional neural network.

PURPOSE: To develop a novel framework to improve the visualization of distal arteries in arterial spin labeling (ASL) dynamic MRA. METHODS: The attenuation of ASL blood signal due to the repetitive application of excitation RF pulses was minimized by splitting the acquisition volume into multiple thin 2D (M2D) slices, thereby reducing the exposure of the arterial blood magnetization to RF pulses while it flows within the brain. To improve the degraded vessel visualization in the slice direction due to the limited minimum achievable 2D slice thickness, a super-resolution (SR) convolutional neural network (CNN) was trained by using 3D time-of-flight (TOF)-MRA images from a large public dataset. And then, we applied domain transfer from 3D TOF-MRA to M2D ASL-MRA, while avoiding acquiring a large number of ASL-MRA data required for CNN training. RESULTS: Compared to the conventional 3D ASL-MRA, far more distal arteries were visualized with higher signal intensity by using M2D ASL-MRA. In general, however, the vessel visualization with a conventional interpolation was prone to be blurry and unclear due to the limited spatial resolution in the slice direction, particularly in small vessels. Application of CNN-based SR transferred from 3D TOF-MRA to M2D ASL-MRA successfully addressed such a limitation and achieved clearer visualization of small vessels than conventional interpolation. CONCLUSION: This study demonstrated that the proposed framework provides improved visualization of distal arteries in later dynamic phases, which will particularly benefit the application of this approach in patients with cerebrovascular disease who have slow blood flow.

ASL lexicon and reporting recommendations: A consensus report from the ISMRM Open Science Initiative for Perfusion Imaging (OSIPI).

The 2015 consensus statement published by the International Society for Magnetic Resonance in Medicine (ISMRM) Perfusion Study Group and the European Cooperation in Science and Technology ( COST) Action ASL in Dementia aimed to encourage the implementation of robust arterial spin labeling (ASL) perfusion MRI for clinical applications and promote consistency across scanner types, sites, and studies. Subsequently, the recommended 3D pseudo-continuous ASL sequence has been implemented by most major MRI manufacturers. However, ASL remains a rapidly and widely developing field, leading inevitably to further divergence of the technique and its associated terminology, which could cause confusion and hamper research reproducibility. On behalf of the ISMRM Perfusion Study Group, and as part of the ISMRM Open Science Initiative for Perfusion Imaging (OSIPI), the ASL Lexicon Task Force has been working on the development of an ASL Lexicon and Reporting Recommendations for perfusion imaging and analysis, aiming to (1) develop standardized, consensus nomenclature and terminology for the broad range of ASL imaging techniques and parameters, as well as for the physiological constants required for quantitative analysis; and (2) provide a community-endorsed recommendation of the imaging parameters that we encourage authors to include when describing ASL methods in scientific reports/papers. In this paper, the sequences and parameters in (pseudo-)continuous ASL, pulsed ASL, velocity-selective ASL, and multi-timepoint ASL for brain perfusion imaging are included. However, the content of the lexicon is not intended to be limited to these techniques, and this paper provides the foundation for a growing online inventory that will be extended by the community as further methods and improvements are developed and established.

Recommendations for quantitative cerebral perfusion MRI using multi-timepoint arterial spin labeling: Acquisition, quantification, and clinical applications.

Accurate assessment of cerebral perfusion is vital for understanding the hemodynamic processes involved in various neurological disorders and guiding clinical decision-making. This guidelines article provides a comprehensive overview of quantitative perfusion imaging of the brain using multi-timepoint arterial spin labeling (ASL), along with recommendations for its acquisition and quantification. A major benefit of acquiring ASL data with multiple label durations and/or post-labeling delays (PLDs) is being able to account for the effect of variable arterial transit time (ATT) on quantitative perfusion values and additionally visualize the spatial pattern of ATT itself, providing valuable clinical insights. Although multi-timepoint data can be acquired in the same scan time as single-PLD data with comparable perfusion measurement precision, its acquisition and postprocessing presents challenges beyond single-PLD ASL, impeding widespread adoption. Building upon the 2015 ASL consensus article, this work highlights the protocol distinctions specific to multi-timepoint ASL and provides robust recommendations for acquiring high-quality data. Additionally, we propose an extended quantification model based on the 2015 consensus model and discuss relevant postprocessing options to enhance the analysis of multi-timepoint ASL data. Furthermore, we review the potential clinical applications where multi-timepoint ASL is expected to offer significant benefits. This article is part of a series published by the International Society for Magnetic Resonance in Medicine (ISMRM) Perfusion Study Group, aiming to guide and inspire the advancement and utilization of ASL beyond the scope of the 2015 consensus article.

Recent Technical Developments in ASL: A Review of the State of the Art.

This review article provides an overview of a range of recent technical developments in advanced arterial spin labeling (ASL) methods that have been developed or adopted by the community since the publication of a previous ASL consensus paper by Alsop et al. It is part of a series of review/recommendation papers from the International Society for Magnetic Resonance in Medicine Perfusion Study Group. Here, we focus on advancements in readouts and trajectories, image reconstruction, noise reduction, partial volume correction, quantification of nonperfusion parameters, fMRI, fingerprinting, vessel selective ASL, angiography, deep learning, and ultrahigh field ASL. We aim to provide a high level of understanding of these new approaches and some guidance for their implementation, with the goal of facilitating the adoption of such advances by research groups and by MRI vendors. Topics outside the scope of this article that are reviewed at length in separate articles include velocity selective ASL, multiple-timepoint ASL, body ASL, and clinical ASL recommendations.

Planning of gamma knife radiosurgery (GKR) for brain arteriovenous malformations using triple magnetic resonance angiography (triple-MRA).

PURPOSE: Intra-arterial Digital Subtraction Angiography (DSA) is the gold standard technique for radiosurgery target delineation in brain Arterio-Venous Malformations (AVMs). This study aims to evaluate whether a combination of three Magnetic Resonance Angiography sequences (triple-MRA) could be used for delineation of brain AVMs for Gamma Knife Radiosurgery (GKR). METHODS: Fifteen patients undergoing DSA for GKR targeting of brain AVMs also underwent triple-MRA: 4D Arterial Spin Labelling based angiography (ASL-MRA), Contrast-Enhanced Time-Resolved MRA (CE-MRA) and High Definition post-contrast Time-Of-Flight angiography (HD-TOF). The arterial phase of the AVM nidus was delineated on triple-MRA by an interventional neuroradiologist and a consultant neurosurgeon (triple-MRA volume). Triple-MRA volumes were compared to AVM targets delineated by the clinical team for delivery of GKR using the current planning paradigm, i.e., stereotactic DSA and volumetric MRI (DSA volume). Difference in size, degree of inclusion (DI) and concordance index (CcI) between DSA and triple-MRA volumes are reported. RESULTS: AVM target volumes delineated on triple-MRA were on average 9.8% smaller than DSA volumes (95%CI:5.6-13.9%; SD:7.14%; p = .003). DI of DSA volume in triple-MRA volume was on average 73.5% (95%CI:71.2-76; range: 65-80%). The mean percentage of triple-MRA volume not included on DSA volume was 18% (95%CI:14.7-21.3; range: 7-30%). CONCLUSION: The technical feasibility of using triple-MRA for visualisation and delineation of brain AVMs for GKR planning has been demonstrated. Tighter and more precise delineation of AVM target volumes could be achieved by using triple-MRA for radiosurgery targeting. However, further research is required to ascertain the impact this may have in obliteration rates and side effects.

Evacuation after the Great East Japan Earthquake is an independent factor associated with hyperuricemia: The Fukushima Health Management Survey.

BACKGROUND AND AIMS: On March 11, 2011, the Great East Japan Earthquake occurred in Japan, with a nuclear accident subsequently occurring at the Fukushima Daiichi Nuclear Power Plant. The disaster forced many evacuees to change particular aspects of their lifestyles. This study assessed the association between evacuation and hyperuricemia based on the Fukushima Health Management Survey from a lifestyle and socio-psychological perspective. METHODS AND RESULTS: This cross-sectional study included 22,812 residents (9391 men and 13,297 women) who underwent both the Comprehensive Health Check and the Mental Health and Lifestyle Survey in fiscal year 2011. Associations between hyperuricemia and lifestyle- and disaster-related factors including evacuation were estimated using a logistic and liner regression analysis. With hyperuricemia defined as uric acid levels >7.0 mg/dL for men and >6.0 mg/dL for women, significant associations were observed between evacuation and hyperuricemia in men (the multivariate-adjusted odds ratio 1.20, 95% confidence interval, 1.05-1.36, p = 0.005), but not in women. In the multivariate-adjusted multiple liner regression analysis, evacuation had significant and positive associations with uric acid levels both in men (ß = 0.084, p = 0.002) and women (ß = 0.060, p < 0.001). CONCLUSION: Evacuation after a natural disaster is an independent factor associated with hyperuricemia.

Association between post-traumatic stress disorder symptoms and bone fractures after the Great East Japan Earthquake in older adults: a prospective cohort study from the Fukushima Health Management Survey.

BACKGROUND: It has been reported that psychological stress affects bone metabolism and increases the risk of fracture. However, the relationship between bone fractures and post-traumatic stress disorder (PTSD) is unclear. This study aimed to evaluate the effects of disaster-induced PTSD symptoms on fracture risk in older adults. METHODS: This study evaluated responses from 17,474 individuals aged ≥ 65 years without a history of fractures during the Great East Japan Earthquake who answered the Mental Health and Lifestyle Survey component of the Fukushima Health Management Survey conducted in 2011. The obtained data could determine the presence or absence of fractures until 2016. Age, sex, physical factors, social factors, psychological factors, and lifestyle factors were subsequently analyzed. Survival analysis was then performed to determine the relationship between the fractures and each factor. Thereafter, univariate and multivariate Cox proportional hazard models were constructed to identify fracture risk factors. RESULTS: In total, 2,097 (12.0%) fractures were observed throughout the follow-up period. Accordingly, univariate and multivariate Cox proportional hazard models showed that PTSD symptoms (total PTSD checklists scoring ≥ 44) [hazard ratio (HR): 1.26; 95% confidence interval (CI): 1.10-1.44; P = 0.001], history of cancer (HR: 1.49; 95% CI: 1.24-1.79; P < 0.001), history of stroke (HR: 1.25; 95% CI: 1.03-1.52; P = 0.023), history of heart disease (HR: 1.30; 95% CI: 1.13-1.50; P < 0.001), history of diabetes (HR: 1.23; 95% CI: 1.09-1.39; P < 0.001), current smoking (HR: 1.29; 95% CI: 1.02-1.63; P = 0.036), and high dissatisfaction with sleep or no sleep at all (HR: 1.33; 95% CI: 1.02-1.74; P = 0.035) promoted a significant increase in fracture risk independent of age and sex. CONCLUSIONS: The present study indicates that disaster-induced PTSD symptoms and insomnia contribute to increased fracture risk among older adults residing in evacuation areas within the Fukushima Prefecture.

Quantification of cerebral perfusion and cerebrovascular reserve using Turbo-QUASAR arterial spin labeling MRI.

PURPOSE: To compare cerebral blood flow (CBF) and cerebrovascular reserve (CVR) quantification from Turbo-QUASAR (quantitative signal targeting with alternating radiofrequency labeling of arterial regions) arterial spin labeling (ASL) and single post-labeling delay pseudo-continuous ASL (PCASL). METHODS: A model-based method was developed to quantify CBF and arterial transit time (ATT) from Turbo-QUASAR, including a correction for magnetization transfer effects caused by the repeated labeling pulses. Simulations were performed to assess the accuracy of the model-based method. Data from an in vivo experiment conducted on a healthy cohort were retrospectively analyzed to compare the CBF and CVR (induced by acetazolamide) measurement from Turbo-QUASAR and PCASL on the basis of global and regional differences. The quality of the two ASL data sets was examined using the coefficient of variation (CoV). RESULTS: The model-based method for Turbo-QUASAR was accurate for CBF estimation (relative error was 8% for signal-to-noise ratio = 5) in simulations if the bolus duration was known. In the in vivo experiment, the mean global CVR estimated by Turbo-QUASAR and PCASL was between 63% and 64% and not significantly different. Although global CBF values of the two ASL techniques were not significantly different, regional CBF differences were found in deep gray matter in both pre- and postacetazolamide conditions. The CoV of Turbo-QUASAR data was significantly higher than PCASL. CONCLUSION: Both ASL techniques were effective for quantifying CBF and CVR, despite the regional differences observed. Although CBF estimated from Turbo-QUASAR demonstrated a higher variability than PCASL, Turbo-QUASAR offers the advantage of being able to measure and control for variation in ATT.

Onset and remission of common mental disorders among adults living in temporary housing for three years after the triple disaster in Northeast Japan: comparisons with the general population.

BACKGROUND: People living in temporary housing for long periods after a disaster are at risk of poor mental health. This study investigated the post-disaster incidence and remission of common mental disorders among adults living in temporary housing for the 3 years following the 2011 Great East Japan Earthquake. METHODS: Three years after the disaster, face-to-face interviews were conducted with 1089 adult residents living in temporary housing in the disaster area, i.e., the shelter group, and a random sample of 852 community residents from non-disaster areas of East Japan. The World Health Organization Composite International Diagnostic Interview was used to diagnose DSM-IV mood, anxiety, and alcohol use disorders. Information on demographic variables and disaster experiences was also collected. RESULTS: Response rates were 49 and 46% for the shelter group and the community residents, respectively. The incidence of mood/anxiety disorder in the shelter group was elevated only in the first year post-disaster compared to that of the general population. The rate of remission for mood and anxiety disorders was significantly lower in the shelter group than in the community residents. The proportion seeking medical treatment was higher in the shelter group. CONCLUSIONS: The onset of common mental disorders increased in the first year, but then levelled off in the following years among residents in temporary housing after the disaster. Remission from incident post-disaster mental disorders was slower in the shelter group than in the general population. Post-disaster mental health service could consider the greater incidence in the first year and prolonged remission of mental disorders among survivors with a long-term stay in temporary housing after a disaster.

Lifestyle factors associated with prevalent and exacerbated musculoskeletal pain after the Great East Japan Earthquake: a cross-sectional study from the Fukushima Health Management Survey.

BACKGROUND: While the prevalence of post-disaster musculoskeletal pain has been documented, its associated disaster-related factors have not been investigated. This study was to investigate the association of lifestyle factors associated with musculoskeletal pain after the Great East Japan Earthquake. METHODS: We conducted a cross-sectional study of 34,919 participants, aged 40-89 years, without any major disabilities at about 1 year after the disaster. The participants were asked about their musculoskeletal pain (low back and limb pain) and lifestyle factors: use of evacuation shelters or temporary housing at any point of time, job loss after the disaster, decreased income after the disaster, current smoking status, current drinking status, lack of sleep, regular exercise, and participation in recreational or community activities. Furthermore, psychological factors, such as traumatic reactions, psychological distress, and uncomfortable symptoms, affecting musculoskeletal pain were assessed. We used multinomial logistic regression analysis to calculate odds ratios of each lifestyle factor for prevalent and prevalent plus exacerbated musculoskeletal pain. RESULTS: Musculoskeletal pain prevalence was 32.8%: 27.6% for prevalent and 5.2% for prevalent plus exacerbated musculoskeletal pain. Multivariable adjusted odds ratios and 95% confidence intervals of lifestyle factors associated with prevalent and prevalent plus exacerbated musculoskeletal pain were as follows: shelter use (prevalent: 1.02, 0.96-1.08; exacerbated: 1.44, 1.29-1.60), job loss (prevalent: 1.03, 0.96-1.10; exacerbated: 1.30, 1.16-1.47), decreased income (prevalent: 1.13, 1.05-1.21; exacerbated: 1.29, 1.14-1.45), current heavy drinking (prevalent: 1.33, 1.21-1.47; exacerbated: 1.38, 1.14-1.68), insomnia (prevalent: 1.22, 1.15-1.29; exacerbated: 1.50, 1.36-1.65), exercising almost daily (prevalent: 0.83, 0.77-0.91; exacerbated: 0.80, 0.68-0.95), and participating in community activities often (prevalent: 0.83, 0.75-0.92; exacerbated: 0.76, 0.61-0.95). CONCLUSIONS: Prevalent and exacerbated musculoskeletal pain were inversely associated with exercising almost daily and participating in recreational or community activities sometimes or often, and positively associated with decreased income, current heavy drinking, and insomnia. Besides, the use of evacuation shelters or temporary housing/job loss was positively associated only with exacerbated musculoskeletal pain. These results suggest that post-disaster lifestyle factors are potentially associated with musculoskeletal pain. To achieve better post-disaster pain management, further studies are needed to confirm the consistency of these results in other disasters and to highlight the underlying causative mechanisms.

Acceleration of vessel-selective dynamic MR Angiography by pseudocontinuous arterial spin labeling in combination with Acquisition of ConTRol and labEled images in the Same Shot (ACTRESS).

PURPOSE: The recently introduced "Acquisition of ConTRol and labEled imaging in the Same Shot" (ACTRESS) approach was designed to halve the scan time of arterial spin labeling (ASL) -based 4D-MRA by obtaining both labeled and control images in a single Look-Locker readout. However, application for vessel-selective labeling remains difficult. The aim of this study was to achieve a combination of ACTRESS and vessel-selective labeling to halve the scan time of vessel-selective 4D-MRA. METHODS: By Bloch equation simulations, Look-Locker pseudocontinuous-ASL (pCASL) was optimized to achieve constant static tissue signal across the multidelay readout, which is essential for the ACTRESS approach. Additionally, a new subtraction scheme was proposed to achieve visualization of the inflow phase even when labeled blood will have already arrived in the distal arteries during the first phase acquisition due to the long duration of the pCASL labeling module. In vivo studies were performed to investigate the signal variation of the static tissue, as well as to assess image quality of vessel-selective 4D-MRA with ACTRESS. RESULTS: In in vivo studies, the mean signal variation of the static tissue was 8.98% over the Look-Locker phases, thereby minimizing the elevation of background signal. This allowed visualization of peripheral arteries and slowly arriving arterial blood with image quality as good as conventional pCASL within half the acquisition time. Vessel-selective pCASL-ACTRESS enabled the separated visualization of vessels arising from internal and external carotid arteries within this shortened acquisition time. CONCLUSION: By combining vessel-selective pCASL and ACTRESS approach, 4D-MRA of a single targeted arterial tree was achieved in a few minutes.

Optimization of the spatial modulation function of vessel-encoded pseudo-continuous arterial spin labeling and its application to dynamic angiography.

PURPOSE: In vessel-encoded pseudo-continuous arterial spin labeling (ve-pCASL), vessel-selective labeling is achieved by modulation of the inversion efficiency across space. However, the spatial transition between the labeling and control conditions is rather gradual, which can cause partial labeling of vessels, reducing SNR-efficiency and necessitating complex postprocessing to decode the vessel-selective signals. The purpose of this study is to optimize the pCASL labeling parameters to obtain a sharper spatial inversion profile of the labeling and thereby minimizing the risk of partial labeling of untargeted arteries. METHODS: Bloch simulations were performed to investigate how the inversion profile was influenced by the pCASL labeling parameters: the maximum (Gmax ) and mean (Gmean ) labeling gradient were varied for ve-pCASL with unipolar and bipolar gradients. The findings in the simulation study were subsequently confirmed in an in vivo volunteer study. Moreover, conventional and optimized settings were compared for 4D-MRA using four-cycle Hadamard ve-pCASL; the visualization of arteries and the presence of the partial labeling were assessed by an expert observer. RESULTS: When using unipolar gradient, lower Gmean resulted in a steeper spatial transition, whereas the width of the control region was broader for higher Gmax . The in vivo study confirmed these findings. When using bipolar gradients, the control region was always very narrow. Qualitative comparison of the 4D-MRA demonstrated lower occurrence of partial labeling when using the optimized gradient parameters. CONCLUSION: The shape of the ve-pCASL inversion profile can be optimized by changing Gmean and Gmax to reduce partial labeling of untargeted arteries.

A framework for motion correction of background suppressed arterial spin labeling perfusion images acquired with simultaneous multi-slice EPI.

PURPOSE: When using simultaneous multi-slice (SMS) EPI for background suppressed (BGS) arterial spin labeling (ASL), correction of through-plane motion could introduce artefacts, because the slices with most effective BGS are adjacent to slices with the least BGS. In this study, a new framework is presented to correct for such artefacts. METHODS: The proposed framework consists of 3 steps: (1) homogenization of the static tissue signal over the different slices to eliminate most inter-slice differences because of different levels of BGS, (2) application of motion correction, and (3) extraction of a perfusion-weighted signal using a general linear model. The proposed framework was evaluated by simulations and a functional ASL study with intentional head motion. RESULTS: Simulation studies demonstrated that the strong signal differences between slices with the most and least effective BGS caused sub-optimal estimation of motion parameters when through-plane motion was present. Although use of the M0 image as the reference for registration allowed 82% improvement of motion estimation for through-plane motion, it still led to residual subtraction errors caused by different static tissue signal between control and label because of different BGS levels. By using our proposed framework, those problems were minimized, and the accuracy of CBF estimation was improved. Moreover, the functional ASL study showed improved detection of visual and motor activation when applying the framework as compared to conventional motion correction, as well as when motion correction was completely omitted. CONCLUSION: When combining BGS-ASL with SMS-EPI, particular attention is needed to avoid artefacts introduced by motion correction. With the proposed framework, these issues are minimized.

Psychometric evaluation of the simplified Japanese version of the Athens Insomnia Scale: The Fukushima Health Management Survey.

We investigated the psychometric properties of the simplified Japanese version of the Athens Insomnia Scale (AIS-SJ) using baseline data from the Fukushima Health Management Survey. Data from 22 878 men and 27 669 women aged 16 years and older were analysed (Mage  = 52.9 ± 18.6). Participants lived in the Fukushima evacuation zone and experienced the Great East Japan Earthquake. The AIS-SJ was used to assess participants' insomnia symptoms, and its validity was examined by administering the Kessler 6-item Psychological Distress Scale (K6) and assessing education, self-rated health and disaster-related experiences. A confirmatory factor analysis revealed that the two-factor model was a better fit than the one-factor model. The AIS-SJ and its subscales had acceptable reliability (Cronbach's alpha, 0.81). Test of measurement invariance confirmed strict invariance across groups for the participants' characteristics of gender and mental illness history, but not for participants' age. AIS-SJ scores exhibited a near-normal distribution (skewness, 0.45; kurtosis, -0.89). There were significant age differences only among women, and gender differences in AIS-SJ scores with small effect sizes. The AIS-SJ scores had weak-to-moderate correlations with mental illness history, bereavement, experiencing the tsunami, experiencing the nuclear power plant incident, housing damage and losing one's job (polyserial correlations, 0.36, 0.17, 0.13, 0.18, 0.13, and 0.15, respectively), and strong correlations with self-rated health (polyserial correlation, 0.51), psychological distress (rs , 0.60) and post-traumatic stress disorder (rs , 0.60). The AIS-SJ is a useful instrument for assessing community dwellers' insomnia symptoms.

Risk Factors for Problem Drinking among Evacuees in Fukushima following the Great East Japan Earthquake: The Fukushima Health Management Survey.

Many studies have consistently reported the bidirectional relationship between problem drinking and psychological distress following a disaster, but the risk factors of problem drinking following a disaster remain unclear. In this study, we therefore aimed to explore the risk factors associated with the incidence of problem drinking among evacuees after the Great East Japan Earthquake of March 11, 2011. We used the data for evacuees of the Fukushima Daiichi nuclear power plant accident, obtained from the Mental Health and Lifestyle Survey. A total of 12,490 individuals from 13 municipalities, which included the evacuation order areas after the accident, completed surveys between 2012 and 2013. The CAGE (Cutting down, Annoyed by criticism, Guilty feeling, and Eye-opener) questionnaire was used to screen the participants for alcohol dependence, and a score ≥ 2 indicated problem drinking. Logistic regression models were applied to investigate the possible predictors of problem drinking. The results showed that insufficient sleep and heavy drinking (≥ 4 drinks per day) were significant risk factors for the incidence of problem drinking in both men and women. Additional risk factors included family financial issues due to the disaster and trauma symptoms among men and a diagnosed history of mental illness among women. Other remaining variables were not significantly associated with problem drinking. The present study is the first to identify the risk factors for problem drinking following a compound disaster. Our findings could be used to develop a primary intervention program to improve evacuees' health and lives following a disaster.

Simultaneous acquisition of perfusion image and dynamic MR angiography using time-encoded pseudo-continuous ASL.

PURPOSE: Both dynamic magnetic resonance angiography (4D-MRA) and perfusion imaging can be acquired by using arterial spin labeling (ASL). While 4D-MRA highlights large vessel pathology, such as stenosis or collateral blood flow patterns, perfusion imaging provides information on the microvascular status. Therefore, a complete picture of the cerebral hemodynamic condition could be obtained by combining the two techniques. Here, we propose a novel technique for simultaneous acquisition of 4D-MRA and perfusion imaging using time-encoded pseudo-continuous arterial spin labeling. METHODS: The time-encoded pseudo-continuous arterial spin labeling module consisted of a first subbolus that was optimized for perfusion imaging by using a labeling duration of 1800 ms, whereas the other six subboli of 130 ms were used for encoding the passage of the labeled spins through the arterial system for 4D-MRA acquisition. After the entire labeling module, a multishot 3D turbo-field echo-planar-imaging readout was executed for the 4D-MRA acquisition, immediately followed by a single-shot, multislice echo-planar-imaging readout for perfusion imaging. The optimal excitation flip angle for the 3D turbo-field echo-planar-imaging readout was investigated by evaluating the image quality of the 4D-MRA and perfusion images as well as the accuracy of the estimated cerebral blood flow values. RESULTS: When using 36 excitation radiofrequency pulses with flip angles of 5 or 7.5°, the saturation effects of the 3D turbo-field echo-planar-imaging readout on the perfusion images were relatively moderate and after correction, there were no statistically significant differences between the obtained cerebral blood flow values and those from traditional time-encoded pseudo-continuous arterial spin labeling. CONCLUSIONS: This study demonstrated that simultaneous acquisition of 4D-MRA and perfusion images can be achieved by using time-encoded pseudo-continuous arterial spin labeling. Magn Reson Med 79:2676-2684, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Acceleration of ASL-based time-resolved MR angiography by acquisition of control and labeled images in the same shot (ACTRESS).

PURPOSE: Noncontrast 4D-MR-angiography (MRA) using arterial spin labeling (ASL) is beneficial because high spatial and temporal resolution can be achieved. However, ASL requires acquisition of labeled and control images for each phase. The purpose of this study is to present a new accelerated 4D-MRA approach that requires only a single control acquisition, achieving similar image quality in approximately half the scan time. METHODS: In a multi-phase Look-Locker sequence, the first phase was used as the control image and the labeling pulse was applied before the second phase. By acquiring the control and labeled images within a single Look-Locker cycle, 4D-MRA was generated in nearly half the scan time of conventional ASL. However, this approach potentially could be more sensitive to off-resonance and magnetization transfer (MT) effects. To counter this, careful optimizations of the labeling pulse were performed by Bloch simulations. In in-vivo studies arterial visualization was compared between the new and conventional ASL approaches. RESULTS: Optimization of the labeling pulse successfully minimized off-resonance effects. Qualitative assessment showed that residual MT effects did not degrade visualization of the peripheral arteries. CONCLUSION: This study demonstrated that the proposed approach achieved similar image quality as conventional ASL-MRA approaches in just over half the scan time. Magn Reson Med 79:224-233, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Arterial spin-labeling is useful for the diagnosis of residual or recurrent meningiomas.

OBJECTIVES: ASL is useful in evaluating tumour blood flow and in detecting hypervascular tumours. The purpose of this study was to assess the additive value of ASL to non-contrast and contrast-enhanced (NC/CE)-T1WI for diagnosing residual or recurrent meningiomas. METHODS: This retrospective study included 25 postoperative patients (20 women, 5 men; median age, 65 [32-85] years) with and 25 gender- and age-matched postoperative patients without residual or recurrent meningiomas. ASL was performed using a pseudocontinuous method. Seven independent observers (two radiology residents, two general radiologists and three neuroradiologists) participated in two reading sessions consisting of only NC/CE-T1WI (first session) or NC/CE-T1WI with ASL (second session). We evaluated the sensitivity and diagnostic performance for the detection of residual or recurrent meningiomas. The diagnostic performance was assessed using a figure of merit (FOM) calculated via jackknife free-response receiver-operating characteristics. Statistical analysis was performed with paired t tests, with a significance level of p < .05. RESULTS: The sensitivities were as follows (NC/CE-T1WI vs. NC/CE-T1WI with ASL): residents (62.1% vs. 70.7%), general radiologists (75.9% vs. 87.9%), neuroradiologists (97.7% vs. 100%) and all observers (81.3% vs. 88.2%). The FOMs were as follows (NC/CE-T1WI vs. NC/CE-T1WI with ASL): residents (0.76 vs. 0.83), general radiologists (0.83 vs. 0.93), neuroradiologists (0.95 vs. 0.99) and all observers (0.86 vs. 0.93). The addition of ASL significantly improved the diagnostic parameters for all observers except neuroradiologists (p <. 05). CONCLUSIONS: ASL improved the detection rate of residual or recurrent meningiomas on NC/CE-T1WI among both radiology residents and general radiologists. KEY POINTS: • ASL improved diagnostic performance for residual/recurrent meningioma compare to NC/CE-T1WI alone. • Diagnostic sensitivity was increased after adding ASL compared with NC/CE-T1WI. • FOM was increased after adding ASL compared with NC/CE-T1WI.

Lifestyle factors and social ties associated with the frequency of laughter after the Great East Japan Earthquake: Fukushima Health Management Survey.

PURPOSE: Although mental health problems such as depression after disasters have been reported, positive psychological factors after disasters have not been examined. Recently, the importance of positive affect to our health has been recognised. We therefore investigated the frequency of laughter and its related factors among residents of evacuation zones after the Great East Japan Earthquake of 2011. METHODS: In a cross-sectional study on 52,320 participants aged 20 years and older who were included in the Fukushima Health Management Survey in Japan's fiscal year 2012, associations of the frequency of laughter with changes in lifestyle after the disaster, such as a changed work situation, the number of family members, and the number of address changes, and other sociodemographic, psychological, and lifestyle factors were examined using logistic regression analysis. The frequency of laughter was assessed using a single-item question: "How often do you laugh out loud?" RESULTS: The proportion of those who laugh almost every day was 27.1%. Multivariable models adjusted for sociodemographic, psychological, and lifestyle factors demonstrated that an increase in the number of family members and fewer changes of address were significantly associated with a high frequency of laughter. Mental health, regular exercise, and participation in recreational activities were also associated with a high frequency of laughter. CONCLUSION: Changes in lifestyle factors after the disaster were associated with the frequency of laughter in the evacuation zone. Future longitudinal studies are needed to examine what factors can increase the frequency of laughter.