The amygdala plays a crucial role in emotion processing and is a key target for understanding the mechanisms underlying major depressive disorder (MDD). This study aimed to investigate the magnetic susceptibility of the amygdala in MDD and examine its association with structural and cerebral blood flow (CBF) changes.

A total of 158 individuals were included in the study, comprising 86 patients with MDD and 72 healthy controls. Depression severity was assessed using Hamilton Depression Rating Scale. Quantitative susceptibility mapping (QSM), T1-weighted, and arterial spin labeling scans were conducted to measure amygdala magnetic susceptibility, volume, and CBF, respectively. Group differences were compared, and associations between susceptibility, volume, and CBF were examined.

The median susceptibility of the amygdala was significantly higher in MDD patients than in controls (all p < 0.01). In the MDD group, increased QSM value in the right amygdala was associated with higher CBF (r = 0.28, p = 0.01), whereas no significant correlation was found between QSM value and volume (p = 0.76). Increased QSM value in the right amygdala was associated with worse depressed mood (r = 0.30, p < 0.01).

Retrospective cross-sectional study conducted at a single center.

The magnetic susceptibility of the amygdala was higher in MDD patients with than in controls. QSM changes in the right amygdala correlated with increased CBF and worse depressed mood, indicating both microstructural and functional alterations. Our results encourage further use of the QSM technique in the elucidation of MDD pathophysiology.

mbASL relies on the use of a series of adiabatic radio-frequency pulses to label successive boli of blood water. As the sequence is a hybrid of pCASL and PASL, it requires an appropriate kinetic model to accurately describe the signal for quantification purposes.

Drawing on the Buxton standard kinetic model, we propose modifications to account for the multiple labeling pulses at variable delays. By varying the number of adiabatic pulses and the thickness of the inversion slab, we maximize SNR and demonstrate the hybrid nature of the sequence.

The mbASL kinetic model is used to produce mbASL cerebral blood flow maps, with average values for mice (110 ml/100 g/min) and rats (96 ml/100 g/min).

We have successfully quantified and validated the mbASL kinetic model and demonstrated that the resulting CBF values agree with the existing literature.

The present work aims to evaluate the performance of three-dimensional (3D) single-shot stack-of-spirals turbo FLASH (SOS-TFL) acquisition for pseudo-continuous arterial spin labeling (PCASL) and velocity-selective ASL (VSASL)-based cerebral blood flow (CBF) mapping, as well as VSASL-based cerebral blood volume (CBV) mapping.

Digital phantom simulations were conducted for both multishot echo planar imaging and spiral trajectories with intershot signal fluctuations. PCASL-derived CBF (PCASL-CBF), VSASL-derived CBF (VSASL-CBF), and CBV (VSASL-CBV) were all acquired using 3D multishot gradient and spin-echo and SOS-TFL acquisitions following background suppression. Both simulation and in vivo images were compared between multishot and single-shot compressed sensing-regularized sensitivity encoding (CS-SENSE) reconstructions.

Artifacts were observed in both simulated multishot echo planar imaging and spiral readouts, as well as in in vivo multishot ASL perfusion images. A high correlation was found between the levels of signal fluctuations among interleaves and the severity of artifacts in both simulated and in vivo data. Image artifacts were more apparent in the inferior region of the brain, especially in CBF scans. These artifacts were effectively eliminated when single-shot CS-SENSE reconstruction was applied to the same data set.

ASL images obtained from 3D segmented gradient and spin-echo or SOS-TFL acquisitions can exhibit artifacts caused by signal fluctuations among different shots, which persist even after the application of background suppression pulses. In contrast, these artifacts were prevented when single-shot CS-SENSE reconstruction was applied to the same SOS-TFL data set.

The different fluid compartments in the developing brain work together to facilitate the delivery of nutrients, neurotransmitters, and neuromodulators. The cerebrospinal fluid and interstitial fluid are essential for clearing macromolecules from the brain, a process that involves the recently discovered meningeal lymphatics. Disruptions in these interactions can hinder normal brain development. Additionally, alterations in systemic fluid dynamics may contribute to neurologic complications, highlighting the need for a more holistic approach to understanding and treating neurologic diseases. MR imaging techniques show potential for detecting these pathologic processes in pediatric neurologic disorders.

Alzheimer's disease (AD) is driven by complex interactions between vascular dysfunction, glymphatic system impairment, and neuroinflammation. Vascular aging, characterized by arterial stiffness and reduced cerebral blood flow (CBF), disrupts the pulsatile forces necessary for glymphatic clearance, exacerbating amyloid-beta (Aβ) accumulation and cognitive decline. This review synthesizes insights into the mechanistic crosstalk between these systems and explores their contributions to AD pathogenesis. Emerging machine learning (ML) tools, such as DeepLabCut and Motion sequencing (MoSeq), offer innovative solutions for analyzing multimodal data and enhancing diagnostic precision. Integrating ML with imaging and behavioral analyses bridges gaps in understanding vascular-glymphatic dysfunction. Future research must prioritize these interactions to develop early diagnostics and targeted interventions, advancing our understanding of neurovascular health in AD.

To present a multi-delay arterial spin labeling (ASL) protocol that obtains the cerebral blood flow (CBF) considering the arterial transit time (ATT), and to assess the correlations with an iodine-123-N-isopropyl-p-iodoamphetamine single-photon emission computed tomography (123I-IMP SPECT) reference standard between multi-delay ASL and single-delay ASL in patients with Moyamoya disease.

We retrospectively analyzed the images of 23 patients with Moyamoya disease (4-73 years, 5 men, 18 women), each of whom was imaged with 10-delay ASL using the variable repetition time (TR) scheme, single-delay ASL, and SPECT. Pearson correlation coefficients were calculated between the CBF values of each ASL and SPECT in the three divisions of the ATT, which we categorized as fast, normal, and slow regions. The threshold for statistical significance was set atP<0.05.

The CBF measured by multi-delay ASL and single-delay ASL were positively correlated with that measured by SPECT, with correlation coefficients of 0.6701 and 0.5637, respectively (P < 0.001). In the fast, normal, and slow ATT divisions, the correlation coefficients between the CBF measured by multi-delay ASL and that measured by SPECT were 0.6745, 0.7055, and 0.6746, respectively. Similarly, the correlations between the CBF measured by single-delay ASL and that measured by SPECT were 0.3811, 0.5090 and 0.6178, respectively.

Multi-delay ASL using the variable TR scheme showed a higher correlation with 123I-IMP SPECT than single-delay ASL for measuring the CBF. The variable TR scheme potentially improved the quantification of CBF on ASL imaging.

Following a brief review of brain neurofluid pathways and the general PET technique, we introduce PET imaging of cerebrospinal fluid and interstitial fluid dynamics. Our summary includes both our published and unpublished observations on the modeling of PET imaging for neurofluid quantification in aging, Alzheimer's disease, and in the presence of amyloid lesions. We identify the limitations of PET imaging and point to validations and potential future directions.

White matter (WM) free water (FW) is a potential imaging marker for cerebral small vessel disease (CSVD). This study aimed to characterize longitudinal changes in WM FW and investigate factors contributing to its elevation in CSVD. We included 80 CSVD patients and 40 normal controls (NCs) with multi-modality MRI data. Cerebral blood flow (CBF) was measured, and fiber alterations were assessed using total apparent fiber density (AFDt). FW were extracted from whole WM, white matter hyperintensities (WMH) and normal-appearing WM (NAWM). Baseline and longitudinal FW elevation were compared between patients and NCs, and between WMH and NAWM. We investigated whether baseline vascular risk factor score, CBF, and AFDt could predict longitudinal FW elevation. Association between cognition and WM FW in CSVD was also assessed. Results shown that FW was higher and increased faster in CSVD compared to NCs and in WMH compared to NAWM. Baseline AFDt predicted longitudinal FW elevation in CSVD patients, while CBF predicted FW changes only in controls. WM FW was associated with cognitive impairment. These findings suggest that CSVD is associated with a faster increase in WM FW. Hypoperfusion and WM fiber alterations might accelerate FW elevation, which is associated with cognitive decline.

This study retrospectively analyzed preoperative arterial spin labeling (ASL) perfusion MRI data of patients with the temporal-insula type of temporal plus epilepsy (TI-TPE). We aimed to investigate the differences in presurgical cerebral blood flow (CBF) changes in TI-TPE patients with different surgical outcomes.

A total of 48 TI-TPE patients confirmed by SEEG were meticulously reviewed for this study. Patients were divided into the seizure-free (SF) group (Engel IA) and the non-seizure-free (NSF) group (Engel IB to IV) according to the Engel seizure classification. The 3D-ASL data of all patients before surgery were analyzed using statistical parametric mapping (SPM) and graph theory analysis. These findings were then compared to healthy controls (HC) based on whole-brain voxel-level analysis and covariance network analysis.

At the voxel-level, both SF and NSF groups showed significantly decreased CBF in the ipsilateral transverse temporal gyrus and insula (TTG/insula), contralateral middle cingulate gyrus, precuneus (MCG/precuneus), and increased CBF in the ipsilateral superior temporal gyrus and the superior temporal pole (STG/STP). Wherein the SF group showed more lower CBF in the contralateral MCG/precuneus, with unique increased CBF in the contralateral STG/insula and decreased CBF in the contralateral calcarine as well. In terms of network attributes, the NSF group showed a significantly higher clustering coefficient (Cp), global efficiency (Eglob), local efficiency (Eloc), shorter shortest path length (Lp), and more extensive abnormal nodes compared to the SF and HC groups. While the SF group has higher synchronicity than the HC group.

Both SF and NSF groups had abnormal CBF changes at the voxel and network levels with different patterns. The SF group showed more obvious regional CBF changes, while the NSF group showed more extended network disruption, which might underlie different seizure outcomes after local surgical resection.

Mutations in the human granulin (GRN) gene are associated with multiple diseases, including dementia disorders such as frontotemporal dementia (FTD) and limbic-predominant age-related TDP-43 encephalopathy (LATE). We studied a Grn knockout (Grn-KO) mouse model in order to evaluate a potential therapeutic strategy for these diseases using nicorandil, a commercially available agonist for the ABCC9/Abcc9-encoded regulatory subunit of the "K+ATP" channel that is well-tolerated in humans. Aged (13 months) Grn-KO and wild-type (WT) mice were treated as controls or with nicorandil (15 mg/kg/day) in drinking water for 7 months, then tested for neurobehavioral performance, neuropathology, and gene expression. Mortality was significantly higher for aged Grn-KO mice (particularly females), but there was a conspicuous improvement in survival for both sexes treated with nicorandil. Grn-KO mice performed worse on some cognitive tests than WT mice, but Morris Water Maze performance was improved with nicorandil treatment. Neuropathologically, Grn-KO mice had significantly increased levels of glial fibrillary acidic protein (GFAP)-immunoreactive astrocytosis but not ionized calcium binding adaptor molecule 1 (IBA-1)-immunoreactive microgliosis, indicating cell-specific inflammation in the brain. Expression of several astrocyte-enriched genes, including Gfap, were also elevated in the Grn-KO brain. Nicorandil treatment was associated with a subtle shift in a subset of detected brain transcript levels, mostly related to attenuated inflammatory markers. Nicorandil treatment improved survival outcomes, cognition, and inflammation in aged Grn-KO mice.

In the brain clearance system, the movement of cerebrospinal fluid (CSF) plays a key role in processing waste products. Previous studies have shown that CSF flow interacts significantly with cerebral blood flow (CBF) during brain waste clearance, but there are no simultaneous measurements and comparisons of these two metrics in humans. This study introduces a novel method for simultaneously measuring CSF pulsatile movement and CBF using pseudo-continuous arterial spin labeling (pCASL) MRI. We conducted a comparative analysis of the correlation between CBF and CSF pulsatile movement in human subjects during breath-holding and motor task conditions. Our findings demonstrate the effectiveness of our proposed technique in measuring CSF pulsatile movement, as validated by comparing results with phase-contrast MRI at corresponding locations. Importantly, we observed a robust positive correlation between CBF and CSF pulsation concurrently measured through pCASL during breath-holding. Furthermore, through inter-subject comparisons of regional CBF and CSF pulsation, we established that higher blood perfusion in putamen, caudate, and pallidum regions, which are included in basal ganglia structure, corresponds to greater CSF pulsatile movement. Our motor tasks significantly increased CBF in the motor cortex, and CSF pulsation measured in the dorsal part around cisterna magna showed a decreasing tendency in the motor condition compared to the resting state, aligning with the Monroe-Kelly doctrine. Accordingly, these results demonstrate the feasibility of simultaneous measurement of CBF and CSF pulsation using the proposed pCASL technique in humans, which warrants further investigation.

To use of statistical methods to assess the diagnostic value of arterial spin labeling (ASL) imaging for follow-up of treated arteriovenous malformations.

We screened references from four databases, namely, the Cochrane Library, PubMed, Web of Science and Embase, that met the requirements. The methodology quality of the included studies was evaluated using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) tool. Data pertaining to diagnostic performance were extracted, and the pooled sensitivity and specificity were calculated using a bivariate mixed-effects model.

We included six studies with a total of 132 patients with arteriovenous malformation (AVM). The merged sensitivity and specificity of ASL for the diagnosis of brain AVMs with incomplete occlusion after treatment were 0.94[0.86-0.98] and 0.99 [0.59-1.00], respectively. According to the SROC curve summary, the AUC was found to be 0.98 [0.96-0.99]. No significant publication bias was observed.

While ASL does not currently match the diagnostic precision of DSA, it is instrumental in post-treatment surveillance of AVM patients. With the development of ASL technology in the future, this technique holds promise as a minimally invasive diagnostic strategy for AVMs with fewer side effects.

CRD42023422087.

Not applicable.

Magnetic resonance imaging (MRI) plays a crucial role alongside clinical and neuropsychological assessments in diagnosing dementia. The recent and ongoing advancements in MRI technology have significantly enhanced the detection and characterization of the specific neurostructural changes seen in various neurodegenerative diseases, thereby significantly increasing the precision of diagnosis. Within this context of perpetual evolution, this review article explores the recent advances in MRI with regard to diagnosing dementia.A retrospective literature review was conducted by searching the PubMed and ScienceDirect databases for the keywords "dementia", "imaging", and "MRI". The inclusion criteria were scientific papers in English that revolved around the role of MRI as a diagnostic tool in the field of dementia. A specific time frame was not determined but the focus was on current articles, with an overall of 20 articles dating from the last 6 years (after 2018), corresponding to 55% of the total number of articles.This review provides a comprehensive overview of the latest advances in the radiologic diagnosis of dementia using MRI, with a particular focus on the last 6 years. Technical aspects of image acquisition for clinical and research purposes are discussed. MRI findings typical of dementia are described. The findings are divided into non-specific findings of dementia and characteristic findings for certain dementia subtypes. This provides information about possible causes of dementia. In addition, developed scoring systems that support MRI findings are presented, including the MTA score for Alzheimer's disease with corresponding illustrative figures.The symbiosis of clinical evaluation with high-field MRI methodologies enhances dementia diagnosis and offers a holistic and nuanced understanding of structural brain changes associated with dementia and its various subtypes. The latest advances, mainly involving the emergence of ultra-high-field (7T) MRI, despite having limited use in clinical practice, mark a pragmatic shift in the field of research. · High-field MRI (3T) and specialized sequences allow for the detection of early structural changes indicative of dementia.. · Characteristic neuroanatomical MRI patterns enable the differentiation between various subtypes of dementia.. · Established scales provide added value to the quantification and categorization of MRI findings in dementia.. · Akl E, Dyrba M, Görß D et al. MRI for diagnosing dementia - update 2024. Rofo 2025; DOI 10.1055/a-2563-0725.

The improvements in imaging technology opened up the possibility to investigate the structure and function of cerebral vasculature and the neurovascular unit with unprecedented precision and gaining deep insights not only on the morphology of the vessels but also regarding their function and regulation related to the cerebral activity. In this review, we will dissect the different imaging capabilities regarding the cerebrovascular tree, the neurovascular unit, the haemodynamic response function, and thus, the vascular-neuronal coupling. We will discuss both clinical and preclinical setting, with a final discussion on the current scenery in cerebrovascular imaging where magnetic resonance imaging and multimodal microscopy emerge as the most potent and versatile tools, respectively, in the clinical and preclinical context.

Medical clearance for return to play (RTP) after sports-related concussion is based on clinical assessment. It is unknown whether brain physiology has entirely returned to preinjury baseline at the time of clearance. In this longitudinal study, we assessed whether concussed individuals show functional and structural MRI brain changes relative to preinjury levels that persist beyond medical clearance. Secondary objectives were to test whether postconcussion changes exceed uninjured brain variability and to correlate MRI findings with clinical recovery time.

For this prospective observational study, healthy athletes without a history of psychiatric, neurologic, or sensory-motor conditions were recruited from a single university sport medicine clinic. Clinical and MRI data were collected at preseason baseline, and those who were later concussed were reassessed at 1-7 days after injury, RTP, 1-3 months after RTP, and 1 year after RTP. A demographically matched control cohort of uninjured athletes was also reassessed at their subsequent preseason baseline. Primary outcomes were postconcussion changes in MRI measures of cerebral blood flow (CBF), white matter mean diffusivity (MD), and fractional anisotropy (FA), evaluated using mixed models. Secondary outcomes were group differences in MRI change scores and correlations of change scores with days to RTP.

Of the 187 athletes enrolled in the study, 25 had concussion with follow-up imaging (20.3 ± 1.5 years, 56% male, 44% female) and were compared with 27 controls (19.7 ± 1.8 years, 44% male, 56% female). Concussed athletes showed statistically significant changes from baseline, including decreased frontoinsular CBF (mean and 95% CI -8.97 [-12.80, -5.01] mL/100 g/minute, z = -4.53), along with increased MD (1.94 × 10-5 [1.26, 2.69] × 10-5, z = 5.48) and reduced FA (-7.30 × 10-3 [-9.80, -5.05] × 10-3, z = -6.07) in the corona radiata and internal capsule. Effects persisted beyond RTP, although only CBF changes exceeded longitudinal variability in controls. For participants with longer recovery periods, significantly greater changes in medial temporal CBF were also seen (ρ = 0.64 [0.44, 0.81], z = 6.80).

This study provides direct evidence of persistent postconcussion changes in CBF and white matter at RTP and up to 1 year later. These results support incomplete recovery of brain physiology at medical clearance, with secondary analyses emphasizing the sensitivity of CBF to clinical recovery.

Cardiovascular (CV) risk factors are associated with cerebrovascular damage and cognitive decline in late-life. However, it is unknown how different ethnic CV risk profiles relate to cerebral haemodynamics in mid-life. We aimed to investigate associations of CV risk factors with cerebral haemodynamics at two timepoints and examine the impact of ethnicity on these measures.

From the HELIUS study (53.0 years, 44.8 % female), participants of Dutch (n = 236), Moroccan (n = 122), or South-Asian Surinamese (n = 173) descent were included. Cerebral blood flow (CBF) and its spatial coefficient of variation (sCoV, an ASL-label arrival measure of macrovascular efficiency) were obtained in grey (GM) and white matter (WM). CV risk factors were assessed 8.4 years [7.4-9.5] (first visit) and 2.2 years [1.8-2.6] (second visit) prior to MRI. Associations of CV risk factors, WM hyperintensities (WMH), and carotid plaques with cerebral haemodynamics were investigated using linear regressions.

CBF and sCoV differed per ethnicity. Only at the second visit associations were found, without an interaction with ethnicity; history of CV disease with lower GM CBF and higher WM sCoV, higher total cholesterol and lower WMH volume with lower WM CBF, smoking with higher WM sCoV, and higher SBP with lower GM sCoV.

These findings suggest that cerebral haemodynamics differ between ethnic groups in midlife. Although no interaction with ethnicity was found in the associations of CV risk factors, the observed differences in CBF and sCoV highlight the need to further explore how ethnic-specific risk profiles may contribute to cerebrovascular pathology over time.

The hippocampus is a highly scrutinized brain structure due to its entanglement in multiple neuropathologies and vulnerability to metabolic insults. This study aims to non-invasively assess the perfusion-mechanics relationship of the hippocampus in the healthy brain across magnetic resonance imaging sequences and magnetic field strengths. In total, 17 subjects (aged 22-35, 7 males/10 females) were scanned with magnetic resonance elastography and arterial spin labelling acquisitions at 3T and 7T in a baseline physiological state. No significant differences in perfusion or stiffness were observed across magnetic field strengths or acquisitions. The hippocampus had the highest vascularity within the deep grey matter, followed closely by the caudate nucleus and putamen. We discovered a positive perfusion-mechanics correlation in the hippocampus across both 3T and 7T groups, with a highly significant correlation overall (R = 0.71, p = 0.0019), which was not observed in the caudate nucleus, a similarly vascular region. Furthermore, we supported our hypothesis that increased perfusion in the hippocampus would lead to greater pulsatile displacement in a small cohort (n = 10). Given that the hippocampus is an exceptionally vulnerable structure, with perfusion deficits often seen in diseases related to learning and memory, our results suggest a unique mechanistic link between metabolic health and stiffness biomarkers in this key region for the first time.

Arterial spin-labeling (ASL) MRI has gained recognition as a quantitative perfusion imaging method for managing patients with brain tumors. Limited studies have so far investigated the reproducibility of ASL-derived perfusion in these patients. This study aimed to evaluate intrasession repeatability and intersession reproducibility of perfusion measurements using 3D pseudocontinuous ASL (pCASL) with TSE Cartesian acquisition with spiral profile reordering (TSE-CASPR) in healthy volunteers (HV) and patients with glioblastoma (GBM) at 3T and to compare them against 3D pCASL with gradient and spin echo (GRASE).

This prospective study (NCT03922984) was approved by the institutional review board, and written informed consent was obtained from all subjects. HV underwent repeat pCASL evaluations 2-4 weeks apart between November 2021 and October 2022. Patients with GBM were recruited for longitudinal MRI from September 2019 to February 2023. Intrasession repeatability (HV and GBM) and intersession reproducibility (HV only) of pCASL were assessed using linear regression, Bland-Altman analyses, the intraclass correlation coefficient (ICC) with 95% CI, and within-subject coefficients of variation (wsCV).

Twenty HV (9 men; mean age, 25.1 [SD, 1.7] years; range, 23-30 years) and 21 patients with GBM (15 men; mean age, 59.8 [SD, 14.3] years; range, 28-81 years) were enrolled. In imaging sessions, 3D pCASL-measured perfusion with TSE-CASPR and GRASE, respectively, achieved high R 2 values (0.88-0.95; 0.93-0.96), minimal biases (-0.46-0.81; -0.08-0.35 mL/100 g/min), high ICCs [95% CI], 0.96-0.98 [0.94-0.98]; 0.96-0.98 [0.92-0.99]), and low wsCV (6.64%-9.07%; 5.20%-8.16%) in HV (n = 20) and patients with GBM (n = 21). Across imaging sessions, 3D pCASL in HV (n = 20) achieved high R 2 values (0.71; 0.82), minimal biases (-1.2; -0.90 mL/100 g/min), high ICC [95% CI] values (0.85 [0.81-0.89]; 0.90 [0.87-0.93]), and low wsCV values (13.82%; 9.98%).

Our study demonstrated excellent intrasession repeatability of 3D pCASL-measured cerebral perfusion in HV and patients with GBM and good-to-excellent intersession reproducibility in HV. 3D pCASL with GRASE performed slightly better than 3D pCASL with TSE-CASPR in HV; however, in patients with GBM, 3D pCASL with TSE-CASPR showed better performance in tumor regions with a nearly 2-fold higher SNR. ASL-measured perfusion could serve as a noncontrast quantitative imaging biomarker to facilitate the management of patients with GBM.

Intraoperative hemorrhage in meningioma surgery represents a critical clinical challenge. In this study, we aimed to investigate the feasibility of predicting intraoperative blood loss (IBL) in non-embolized meningiomas using the cerebral blood flow (CBF) information estimated from three-dimensional (3D) pseudo-continuous arterial spin labeling (pCASL) magnetic resonance imaging (MRI).

A total of 48 non-embolized meningioma patients who underwent preoperative 3D pCASL from September 2017 to July 2024 were retrospectively studied. IBL was recorded during the operation. The meningioma's CBF was normalized to the contralateral normal gray matter's CBF, yielding the normalized CBF, which was analyzed, along with MRI-based tumor anatomy including volume, the volume ratio between tumor and total brain (VRTB), maximum tumor diameter, and location. Patients were divided into high and low blood loss groups at a 400 mL threshold. Logistic regression was employed to find the parameters correlated with IBL. Diagnostic performance was assessed using receiver operating characteristic (ROC) curve analysis [area under the curve (AUC)] and the Delong test.

Clinical and radiological analysis revealed significant differences in tumor volume, VRTB, maximum tumor diameter, and normalized CBF between subgroups. Multivariate logistic regression identified VRTB [odds ratio (OR) =2.055, 95% confidence interval (CI): 1.250-3.379], and normalized CBF (OR =1.428, 95% CI: 1.109-1.838) as significant predictors of elevated IBL. Optimal cutoff values were 3.293% for VRTB and 1.817 for normalized CBF. The AUCs were 0.751 for VRTB and 0.683 for normalized CBF, with no significant difference between them (Delong test, P=0.582). The combined risk factors' AUC, including both VRTB and normalized CBF, was 0.867, showing a significant difference from normalized CBF (P=0.010) but not from VRTB (P=0.099).

The normalized CBF and VRTB may serve as promising non-invasive imaging biomarkers to predict IBL and guide meningioma surgery.

Normal aging has been associated with increased arterial transit time (ATT) and reduced cerebral blood flow (CBF). However, age-related patterns of ATT and CBF and their relationship remain unclear. This is partly due to the lengthy scan times required for ATT measurements, which caused previous age-related CBF studies to not fully account for transit time. In this work, we aimed to elucidate age-related ATT and ATT-corrected CBF patterns. We examined 131 healthy subjects aged 19 to 82 years old using two pseudo-continuous arterial spin labeling (PCASL) MRI scans: one to measure fast low-resolution ATT maps with five post-labeling delays and the other to measure high-resolution perfusion-weighted maps with a single post-labeling delay. Both ATT and perfusion-weighed maps were applied with vessel suppression. We found that ATT increases with age in the frontal, temporoparietal, and occipital regions, with a more pronounced elongation in males compared to females in the middle temporal gyrus. ATT-corrected CBF decreases with age in several brain regions, including the anterior cingulate, insula, posterior cingulate, angular, precuneus, supramarginal, frontal, parietal, superior and middle temporal, occipital, and cerebellar regions, while remaining stable in the inferior temporal and subcortical regions. In contrast, without ATT correction, we detected artifactual decreases in the inferior temporal and precentral regions. These findings suggest that ATT provides valuable and independent insights into microvascular deficits and should be incorporated into CBF measurements for studies involving aging populations.

Empathy is characterized as the ability to share one's experience and is associated with altruism. Previous work using blood oxygen level-dependent (BOLD) functional MRI (fMRI) has found that empathy is associated with greater activation in brain mechanisms supporting mentalizing (temporoparietal junction), salience (anterior cingulate cortex; insula), and self-reference (medial prefrontal cortex; precuneus). However, BOLD fMRI has some limitations that may not reliably capture the tonic experience of empathy. To address this, the present study used a perfusion-based arterial spin labeling fMRI approach that provides direct a quantifiable measurement of cerebral blood flow (1 mL/100 g tissue/min) and is less susceptible to low-frequency fluctuations and empathy-based "carry-over" effects that may be introduced by BOLD fMRI-based block designs. Twenty-nine healthy females (mean age = 29 years) were administered noxious heat (48°C; left forearm) during arterial spin labeling fMRI. In the next 2 fMRI scans, female volunteers viewed a stranger (laboratory technician) and their romantic partner, respectively, receive pain-evoking heat (48°C; left forearm) in real-time and positioned proximal to the scanner during fMRI acquisition. Visual analog scale (0 = "not unpleasant"; 10 = "most unpleasant sensation imaginable") empathy ratings were collected after each condition. There was significantly ( P = 0.01) higher empathy while viewing a romantic partner in pain and greater cerebral blood flow in the right temporoparietal junction, amygdala, anterior insula, orbitofrontal cortex, and precuneus when compared with the stranger. Higher empathy was associated with greater precuneus and primary visual cortical activation. The present findings indicate that brain mechanisms supporting the embodiment of another's experience is associated with higher empathy.

B0 field inhomogeneity within the brain-feeding arteries is a major issue for pseudo-continuous arterial spin labeling (PCASL) at 7 T because it reduces the labeling efficiency and leads to a loss of perfusion signal. This study aimed to develop a vessel-specific dynamic B0 field shimming method for 7 T PCASL to improve the labeling efficiency by correcting off-resonance within the arteries in the labeling region.

We implemented a PCASL sequence with dynamic B0 shimming at 7 T that compensates for B0 field offsets in the brain-feeding arteries by updating linear shimming terms and adding a phase increment to the PCASL RF pulses. Rapidly acquired vessel-specific B0 field maps were used to calculate dynamic B0 shimming parameters. We evaluated both 2D and 3D variants of our method, comparing their performance against the established global frequency offset and optimal encoding scheme-based corrections. Cerebral blood flow (CBF) maps were quantified before and after corrections, and CBF values from different methods were compared across the whole brain, white matter, and gray matter regions.

All off-resonance correction methods significantly recovered perfusion signals across the brain. The proposed vessel-specific dynamic B0 shimming method improved the labeling efficiency while maintaining optimal static shimming in the imaging region. Perfusion-weighted images demonstrated the superiority of the 3D dynamic B0 shimming method compared to global or 2D-based correction approaches. CBF analysis revealed that 3D dynamic B0 shimming significantly increased CBF values relative to the other methods.

Our proposed dynamic B0 shimming method offers a significant advancement in PCASL robustness and effectiveness, enabling full utilization of 7 T ASL high sensitivity and spatial resolution.

To investigate the value of arterial spin labeling (ASL) and radiological depth of invasion (rDOI) in predicting long-term treatment outcomes in nonmetastatic nasopharyngeal carcinoma (NPC).

A total of 113 patients with NPC were included and randomly divided into training (n = 81) and validation (n = 32) cohorts. Tumor blood flow (TBF) parameters derived from the ASL (TBFMean, TBFSD, and nTBF) were obtained. Two radiologists independently measured the rDOI in both axial (rDOI_a) and coronal (rDOI_c) planes, subsequently categorizing patients into low-risk and high-risk groups. Spearman analysis was used to explore the correlation. In the training cohort, ASL-based, ASL + rDOI, and TNM models were constructed using univariate and multivariate Cox regression analyses. Model performance, including calibration, robustness, discrimination, and clinical utility, was assessed in both training and validation cohorts. The net classification index (NRI) and integrated discrimination improvement (IDI) were calculated.

The median follow-up duration was 63.4 (56.2, 100.1) months. Disease progression and death occurred in 45 (39.8 %) and 32 (28.3 %) patients, respectively. TBFMean and rDOI were independent predictors of overall survival (OS) (hazard ratios [HR], 0.973 and 2.975, respectively) and progression-free survival (PFS) (HR, 0.985 and 2.207, respectively). rDOI_a and rDOI_c were significantly correlated with T stage (r = 0.538-0.738, P ≤ 0.002). The ASL + rDOI model demonstrated good robustness and clinical utility in both training and validation cohorts. Post-hoc subgroup analysis showed favorable results.

TBFMean and rDOI can predict survival outcomes in patients with NPC. Adding rDOI further improved the prediction performance.

The mechanism underlying the possible causal association between long-term sleep disruption and Alzheimer's disease remains unclear Musiek et al. 2015. A hypothesised pathway through increased brain amyloid load was not confirmed in previous work in our cohort of maritime pilots with long-term work-related sleep disruption Thomas et al. Alzheimer's Res Ther 2020;12:101. Here, using functional MRI, T2-FLAIR, and arterial spin labeling MRI scans, we explored alternative neuroimaging biomarkers related to both sleep disruption and AD: resting-state network co-activation and between-network connectivity of the default mode network (DMN), salience network (SAL) and frontoparietal network (FPN), vascular damage and cerebral blood flow (CBF). We acquired data of 16 maritime pilots (56 ± 2.3 years old) with work-related long-term sleep disruption (23 ± 4.8 working years) and 16 healthy controls (59 ± 3.3 years old), with normal sleep patterns (Pittsburgh Sleep Quality Index ≤ 5). Maritime pilots did not show altered co-activation in either the DMN, FPN, or SAL and no differences in between-network connectivity. We did not detect increased markers of vascular damage in maritime pilots, and additionally, maritime pilots did not show altered CBF-patterns compared to healthy controls. In summary, maritime pilots with long-term sleep disruption did not show neuroimaging markers indicative of preclinical AD compared to healthy controls. These findings do not resemble those of short-term sleep deprivation studies. This could be due to resiliency to sleep disruption or selection bias, as participants have already been exposed to and were able to deal with sleep disruption for multiple years, or to compensatory mechanisms Mentink et al. PLoS ONE. 2021;15(12):e0237622. This suggests the relationship between sleep disruption and AD is not as strong as previously implied in studies on short-term sleep deprivation, which would be beneficial for all shift workers suffering from work-related sleep disruptions.

One possible contributing factor for cerebral blood flow (CBF) decline in normal aging is the increase in partial volume effects due to brain atrophy, as cortical thinning can exacerbate the contamination of gray-matter (GM) voxels by other tissue types. This work investigates CBF changes in normal aging of a large elderly cohort aged 54 to 84 and how correction for partial volume effects that would accommodate potential changes in GM might affect this.

The study cohort consisted of 474 participants aged 54 to 84 years using pseudo-continuous arterial spin labeling MRI. A volumetric pipeline and a surface-based pipeline were applied to measure global and regional perfusion. Volumetric regions of interest (ROIs) included GM, cerebral white matter, vascular territories, and the brain atlas from the UK Biobank. The cortical parcellation was using Desikan-Killiany atlas. Non-partial volume effect correction (PVEc) and PVEc GM-CBF changes with aging were modeled using linear regressions.

Global GM CBF decreased by 0.17 mL/100 g/min per year with aging before PVEc (p < 0.05) and was 0.18 mL/100 g/min after PVEc (p < 0.05). All cortical parcels exhibited CBF decreases with age before PVEc. After PVEc, seven parcels retained decreasing trends. However, GM CBF demonstrated increase with age after PVEc in three parcels.

Although decreases in global perfusion are observed with aging before PVEc, perfusion variations appear to be more regionally selective after PVEc. This supports the understanding that variation in cerebral perfusion with age observed with imaging is influenced by regional changes in anatomy that can be accommodated with PVEc, but perfusion variation is still observable even after PVE is accounted for.

The study investigated the sensitivity of a novel MRI-based OEF mapping, quantitative susceptibility mapping plus quantitative blood oxygen level-dependent imaging (QSM+qBOLD or QQ), to physiological changes, particularly increased oxygen extraction fraction (OEF) by using hyperventilation as a vasoconstrictive stimulus. While QQ's sensitivity to decreased OEF during hypercapnia has been demonstrated, its sensitivity to increased OEF levels, crucial for cerebrovascular disorders like vascular dementia and Parkinson's disease, remains unexplored. In comparison with a previous QSM-based OEF, we evaluated QQ's sensitivity to high OEF values. MRI data were obtained from 11 healthy subjects during resting state (RS) and hyperventilation state (HV) using a 3 T MRI with a three-dimensional multi-echo gradient echo sequence (mGRE) and arterial spin labeling (ASL). Region of interest (ROI) analysis and paired t-tests were used to compare OEF, CMRO2 and CBF between QQ and QSM. Similar to QSM, QQ showed higher OEF during HV compared to RS: in cortical gray matter, QQ-OEF and QSM-OEF was 36.4  ±   4.7% and 35.3  ±   12.5% at RS and 45.0  ±   11.6% and 45.0  ±   14.8% in HV, respectively. These findings demonstrate QQ's ability to detect physiological changes and suggest its potential in studying brain metabolism in neurological disorders.

By leveraging the small-vessel specificity of velocity-selective arterial spin labeling (VSASL), we present a novel technique for measuring cerebral MicroVascular Pulsatility named MVP-VSASL.

We present a theoretical model relating the pulsatile, cerebral blood flow-driven VSASL signal to the microvascular pulsatility index (PI $$ \mathrm{PI} $$ ), a widely used metric for quantifying cardiac-dependent fluctuations. The model describes the dependence of thePI $$ \mathrm{PI} $$ of VSASL signal (denotedPI VS $$ {\mathrm{PI}}_{\mathrm{VS}} $$ ) on bolus durationτ $$ \tau $$ (an adjustable VSASL sequence parameter) and provides guidance for selecting a value ofτ $$ \tau $$ that maximizes the SNR of thePI VS $$ {\mathrm{PI}}_{\mathrm{VS}} $$ measurement. The model predictions were assessed in humans using data acquired with retrospectively cardiac-gated VSASL sequences over a broad range ofτ $$ \tau $$ values. In vivo measurements were also used to demonstrate the feasibility of whole-brain voxel-wise pulsatility mapping, assess intrasession repeatability ofPI VS $$ {\mathrm{PI}}_{\mathrm{VS}} $$ , and illustrate the potential of this method to explore an association with age.

The theoretical model showed excellent agreement to the empirical data in a gray matter region of interest (averageR 2 $$ {\mathrm{R}}^2 $$ value of 0.898± $$ \pm $$ 0.107 across six subjects). We further showed excellent intrasession repeatability of the pulsatility measurement (ICC = 0.960 $$ \mathrm{ICC}=0.960 $$ ,p < 0.001 $$ p<0.001 $$ ) and the potential to characterize associations with age (r = 0.554 $$ r=0.554 $$ ,p = 0.021 $$ p=0.021 $$ ).

We have introduced a novel, VSASL-based cerebral microvascular pulsatility technique, which may facilitate investigation of cognitive disorders where damage to the microvasculature has been implicated.

While the associations of mid-life cardiovascular risk factors with late-life white matter lesions (WMH) and cognitive decline have been established, the role of cerebral haemodynamics is unclear. We investigated the relation of late-life (69-71 years) arterial spin labelling (ASL) MRI-derived cerebral blood flow (CBF) with life-course cardiovascular risk factors (36-71 years) and late-life white matter hyperintensity (WMH) load in 282 cognitively healthy participants (52.8% female). Late-life (69-71 years) high systolic (B = -0.15) and diastolic (B = -0.25) blood pressure, and mean arterial pressure (B = -0.25) were associated with low grey matter (GM) CBF (p < 0.03), and white matter CBF (B = -0.25; B = -0.15; B = -0.13, p < 0.03, respectively). The association between systolic blood pressure and GM CBF differed between sexes (male/female B = -0.15/0.02, p = 0.04). No associations were found with early- or mid-life cardiovascular risk factors. Furthermore, WMHs were associated with cerebral haemodynamics but not cardiovascular risk factors. These findings suggest that cerebral blood flow autoregulation is able to maintain stable global cerebral haemodynamics until later in life. Future studies are encouraged to investigate why cardiovascular risk factors have differential effects on haemodynamics and WMH, and their implications for cognitive decline.

Quantitative susceptibility mapping (QSM), a magnetic resonance imaging (MRI) modality sensitive to deoxyhemoglobin, is a promising method for measuring cerebral oxygenation in human neonates. Paramagnetic sources, like deoxyhemoglobin, however, can be obscured by diamagnetic sources such as water and myelin. This study evaluated whether QSM images, or isolated paramagnetic components, are more accurate for measuring oxygenation of cerebral veins of preterm neonates, and explored oxygenation differences between the major cerebral veins.

19 preterm neonates were scanned on at term equivalent age on a 3T MRI using a multi-echo susceptibility-weighted imaging sequence. Susceptibility values were calculated from QSM images to determine oxygen saturation (SvO2) in the superior sagittal sinus (SSS) and central cerebral veins (CCV). The paramagnetic components of QSM images were isolated, and SvO2 values were recalculated.

The mean SvO2 values from QSM were 72.4% (SD, 3.4%) for the SSS and 68.7% (SD, 3.5%) for the CCV. SvO2 values for paramagnetic components were 58.1% (SD, 7.3%) for the SSS and 57.7% (SD, 7.0%) for the CCV.

While paramagnetic component decomposition yielded SSS values closer to those found in the literature, it increased variability. No significant oxygenation differences were found between the SSS and CCV, contrasting with prior studies.

This study evaluated the use of QSM and its paramagnetic components to measure cerebral oxygenation in neonates. By comparing susceptibility-derived oxygen saturation (SvO2) in the superior sagittal sinus (SSS) and central cerebral veins (CCV), it adds to the field of neonatal cerebral oxygenation measurement. Decomposing QSM into paramagnetic components shows potential for improving SvO2 accuracy, particularly in the SSS, though variability remains a challenge. The results suggest no significant oxygenation difference between the SSS and CCV, contrasting with previous findings, indicating a need for further research on neonatal venous oxygenation.

Velocity-selective arterial spin labelling (VSASL) MRI is insensitive to prolonged arterial transit time. This is an advantage over other arterial spin labelling schemes, where long arterial transit times can lead to bias. Therefore, VSASL can be used with greater confidence to study perfusion in the presence of long arterial transit times, such as in the ageing brain, in vascular pathologies, and cancer, or where arterial transit time changes, such as during measurement of cerebrovascular reactivity (CVR). However, when calculating perfusion (cerebral blood flow, CBF, in the brain) from VSASL signal, it is assumed that a vascular crushing module, defining the duration of the bolus, is applied before the arrival of the trailing edge. The early arrival of the trailing edge of the labelled bolus of blood will cause an underestimation of perfusion. Here we measure bolus duration in adult, healthy human brains, both at rest and during elevated CBF during CO2 breathing (5% inspired CO2). Grey matter bolus duration was of 2.20 ± 0.35 s / 2.22 ± 0.53 s / 2.05 ± 0.34 s (2/3/4 cm/s vcutoff) at rest, in close agreement with a prior investigation. However, we observed a significant decrease in bolus duration during hypercapnia, and a matched reduction in CVR above a labelling delay of approximately 1.2 s. The reduction in CVR and bolus duration was spatially heterogenous, with shorter hypercapnic bolus durations observed in the frontal lobe (1.31 ± 0.54 s) and temporal lobes (1.36 ± 0.24 s), compared to the occipital lobe (1.50 ± 0.26 s). We place these results in context of recommendations from a recent consensus paper, which recommends imaging 1.4 s after the label, which could lead to CBF underestimation in conditions with fast flow or during CVR measurements. These results can be used to inform the experimental design of future VSASL studies, to avoid underestimating perfusion by imaging after the arrival of the trailing edge of the labelled bolus.

White matter hyperintensities (WMH) may be indicative of age-related cerebrovascular diseases and contribute to cognitive and functional decline. Normal appearing WM (NAWM) adjacent to WMH, termed "penumbra," is known to be vulnerable to future WMH pathology. WM integrity can be evaluated using multiple magnetic resonance imaging (MRI) modalities. We aimed to identify MRI features predictive of WMH growth and to compare the implications of these features based on spatial proximity to existing WMH versus signal features in baseline NAWM. We used baseline and 5-year follow-up MRI scans in 485 middle-aged participants form the Coronary Artery Risk Development in Young Adults (CARDIA). Multimodal MRI at baseline, including fluid attenuated inversion recovery (FLAIR), diffusion tensor imaging (DTI), and cerebral blood flow (CBF), was measured within WM ROIs including baseline WMH and regions that later developed into new WMH, within and external to the baseline penumbra. Overall, we found that 80% of new WMH appeared within the baseline penumbra. We also found lower fractional anisotropy (FA) and CBF and higher FLAIR and median diffusivity (MD) in NAWM at baseline in regions with subsequent WMH growth compared to those without WMH growth. For NAWM regions defined by signal features, subthreshold FA and suprathreshold MD and FLAIR abnormality at baseline were the most robust predictors of WMH growth. Baseline systolic blood pressure had significant associations with baseline abnormalities in NAWM and subsequently with cognitive decline, particularly for FA and MD measures. The findings support the use of DTI as the predictor of WMH growth, which is correlated with subtle, adverse WM alterations and cognitive function years before developing to WMH. The results may contribute to future clinical trials aimed at preserving WM integrity.

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation method that has been increasingly used to treat psychiatric disorders, including tobacco use disorder. However, the neural mechanisms underlying the effects of rTMS remain unclear. This study aimed to examine the effectiveness of rTMS in smoking cessation and to explore the underlying neural mechanism of the treatment effect. In Experiment 1, we recruited 60 participants who smoked cigarettes and 60 healthy controls and used their baseline cerebral blood flow (CBF) measured by arterial spin labelling perfusion to determine the group-level difference in CBF. In Experiment 2, we used the left dorsolateral prefrontal cortex (DLPFC) as the target for subsequent 5-day rTMS treatment at a frequency of 10 Hz with 2000 pulses to observe the impact of rTMS on CBF, Fagerström test for nicotine dependence scores and Tiffney questionnaire on smoking urges scores. In Experiment 3, we measured functional connectivity to monitor the functional changes induced by rTMS and assessed their associations with smoking cravings and nicotine dependence scores. In Experiment 1, participants who smoked cigarettes presented significantly higher CBF in the left DLPFC and bilateral anterior cingulate cortex than healthy controls. In Experiment 2, rTMS significantly decreased CBF in the DLPFC and reduced Fagerström test for nicotine dependence scores and Tiffney questionnaire on smoking urges scores. In Experiment 3, rTMS increased functional connectivity between the left DLPFC and the bilateral superior frontal gyrus, right DLPFC, bilateral precuneus and bilateral parahippocampus in participants, who smoked cigarettes. Regional CBF is a tool to identify tobacco use disorder-related regional brain markers and targets for reducing nicotine dependence and smoking cravings through rTMS. A neural mechanism of left DLPFC rTMS may involve a reduction in CBF in the target area and an increase in functional connectivity between the target area and the DLPFC-striatal pathways.

Currently, the selection of patients with acute anterior large vessel occlusions (LVOs) for endovascular thrombectomy (EVT) is primarily based on dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI) or computed tomography (CT) perfusion imaging. This study investigated the consistency between hypoperfused tissue (HPT) (time to maximum >6 s, Tmax >6 s) volumes estimated by corrected and uncorrected multidelay pseudo-continuous arterial spin labeling (pCASL) and DSC-PWI in patients with anterior LVOs and also evaluated the diagnostic performances in selecting patients with acute LVOs for EVT.

This retrospective study enrolled patients with acute (n=108) and symptomatic chronic (n=90) LVOs. Shapiro-Wilk tests and receiver operating characteristic (ROC) analyses were used. Intraclass correlation coefficient (ICC) compared the consistency of HPT volume calculated by DSC-PWI and multidelay pCASL.

Multidelay pCASL with different thresholds in acute LVOs were 128.8 [interquartile range (IQR), 76.2-181.1] mL in uncorrected relative cerebral blood flow (rCBF) <40%, 84.1 (IQR, 36.8-133.9) mL in uncorrected CBF <20 mL·100 g-1·min-1 , and 74.4 (IQR, 26.2-118.0) mL in corrected CBF <20 mL·100 g-1·min-1, which were comparable to the volume of 69.5 (IQR, 20.0-121.4) mL automatically determined by Tmax >6 s in DSC-PWI, and showed substantial consistency after correction (ICC =0.742). Multidelay pCASL with different thresholds in symptomatic chronic LVOs was 78.3 (IQR, 53.5-129.4) mL, 59.8 (IQR, 16.6-98.5) mL and 36.4 (IQR, 10.1-85.3) mL, which were comparable to the volume of 0 (IQR, 0-36.4) mL in DSC-PWI, and showed substantial consistency after correction (ICC =0.617). Using DEFUSE 3 as the reference standard, the CBF corrected by arterial transit time (ATT) showed good performance in selecting patients for EVT (area under the curve 0.804, 95% confidence interval: 0.717-0.891).

The volume of HPT defined by corrected CBF <20 mL·100 g-1·min-1 is consistent with that of DSC-PWI in acute and chronic symptomatic LVOs patients. Multidelay pCASL adjusted by ATT is more applicable to clinical routine.

Hemodynamic measurements such as cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) can provide useful information for the diagnosis and characterization of brain tumors. Previous work showed that arterial spin labeling (ASL) in combination with vasoactive stimulation enabled simultaneous non-invasive evaluation of both parameters, however this approach had not been previously tested in tumors. The aim of this work was to investigate the application of this technique, using a pseudo-continuous ASL (PCASL) sequence combined with breath-holding at 3 T, to measure CBF and CVR in high-grade gliomas and metastatic lesions, and to explore differences across tumoral-peritumoral regions and tumor types. To that end, 27 patients with brain tumor were studied. Baseline CBF and CVR were measured in tumor, edema, and gray matter (GM) volumes-of-interest (VOIs). Peritumoral ipsilateral ring-shaped VOIs were also generated and mirrored to the contralateral hemisphere. Differences in baseline CBF and CVR were evaluated between contralateral and ipsilateral GM, contralateral and ipsilateral peritumoral rings, and among VOIs and tumor types. CBF in the tumor was higher in grade 4 gliomas than metastases. In grade 4 gliomas, edema had lower CBF than the tumor and contralateral GM. CVR values were different between grade 3 and grade 4 gliomas, and between grade 4 and metastases. CVR values in the tumor were lower compared to the contralateral GM. Differences in CVR between contralateral and ipsilateral-ring VOIs were also found in grade 4 gliomas, presumably suggesting tumor infiltration within the peritumoral tissue. A cut-off value for CVR of 27.9%-signal-change is suggested to differentiate between grade 3 and grade 4 gliomas (specificity = 83.3%, sensitivity = 70.6%). In conclusion, CBF and CVR mapping with ASL offered insights into the perilesional environment that could help to detect infiltrative disease, particularly in grade 4 gliomas. CVR emerged as a potential biomarker to differentiate between grade 3 and grade 4 gliomas.

This study integrated neuroimaging and neurochemistry data to explore brain mechanisms in chronic insomnia disorder (CID) and the neuromodulatory effects of acupuncture. We analyzed a cross-sectional arterial spin labeling (ASL) dataset (N = 197) of CID patients and healthy controls to identify cerebral blood flow (CBF) changes. Additionally, a longitudinal ASL dataset (N = 44) examined CBF changes in CID patients after a 4-week acupuncture treatment or on a waitlist. We then assessed the impact of 19 neurotransmitter receptors/transporters on these CBF alterations. In cross-sectional comparisons, CID patients exhibited increased CBF in cortical areas and decreased CBF in subcortical regions, correlating with insomnia severity. In longitudinal comparisons, acupuncture treatment enhanced subcortical CBF and alleviated insomnia symptoms, changes not observed in the waitlist group. The left putamen was identified as an overlapping subcortical region involved in both CID-related changes and post-treatment alterations. Moreover, the CBF patterns induced by acupuncture negatively correlated with the abnormal patterns in CID patients, and both were significantly associated with GABAa and dopamine-D1 receptor densities. The observed decrease in CBF in the left putamen could potentially serve as a neural biomarker for CID, while acupuncture may alleviate insomnia symptoms by increasing CBF in this region, potentially through the modulation of GABAa and D1 receptor expressions.