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ObjectiveTo determine the feasibility and biologic correlations of dynamic susceptibility contrast (DSC), dynamic contrast enhanced (DCE), and quantitative maps derived from contrast leakage effects obtained simultaneously in gliomas using dynamic spin-and-gradient-echo echoplanar imaging (dynamic SAGE-EPI) during a single contrast injection.Materials and methodsThirty-eight patients with enhancing brain gliomas were prospectively imaged with dynamic SAGE-EPI, which was processed to compute traditional DSC metrics (normalized relative cerebral blood flow [nrCBV], percentage of signal recovery [PSR]), DCE metrics (volume transfer constant [Ktrans], extravascular compartment [ve]), and leakage effect metrics: ΔR2,ss* (reflecting T2*-leakage effects), ΔR1,ss (reflecting T1-leakage effects), and the transverse relaxivity at tracer equilibrium (TRATE, reflecting the balance between ΔR2,ss* and ΔR1,ss). These metrics were compared between patient subgroups (treatment-naïve [TN] vs recurrent [R]) and biological features (IDH status, Ki67 expression).ResultsIn IDH wild-type gliomas (IDHwt-i.e., glioblastomas), previous exposure to treatment determined lower TRATE (p = 0.002), as well as higher PSR (p = 0.006), Ktrans (p = 0.17), ΔR1,ss (p = 0.035), ve (p = 0.006), and ADC (p = 0.016). In IDH-mutant gliomas (IDHm), previous treatment determined higher Ktrans and ΔR1,ss (p = 0.026). In TN-gliomas, dynamic SAGE-EPI metrics tended to be influenced by IDH status (p ranging 0.09-0.14). TRATE values above 142 mM-1s-1 were exclusively seen in TN-IDHwt, and, in TN-gliomas, this cutoff had 89% sensitivity and 80% specificity as a predictor of Ki67 > 10%.ConclusionsDynamic SAGE-EPI enables simultaneous quantification of brain tumor perfusion and permeability, as well as mapping of novel metrics related to cytoarchitecture (TRATE) and blood-brain barrier disruption (ΔR1,ss), with a single contrast injection.Clinical relevance statementSimultaneous DSC and DCE analysis with dynamic SAGE-EPI reduces scanning time and contrast dose, respectively alleviating concerns about imaging protocol length and gadolinium adverse effects and accumulation, while providing novel leakage effect metrics reflecting blood-brain barrier disruption and tumor tissue cytoarchitecture.Key points• Traditionally, perfusion and permeability imaging for brain tumors requires two separate contrast injections and acquisitions. • Dynamic spin-and-gradient-echo echoplanar imaging enables simultaneous perfusion and permeability imaging. • Dynamic spin-and-gradient-echo echoplanar imaging provides new image contrasts reflecting blood-brain barrier disruption and cytoarchitecture characteristics.

The no‐reflow phenomenon is a potential contributor to poor outcome despite successful thrombectomy. There are multiple proposed imaging‐based definitions of no‐reflow leading to wide variations in reported prevalence. We investigated the agreement between existing imaging definitions and compared the characteristics and outcomes of patients identified as having no‐reflow. Methods: We performed an external validation of 4 existing published definitions of no‐reflow in thrombectomy patients with extended Thrombolysis in Cerebral Infarction scale 2c to 3 (eTICI2c‐3) angiographic reperfusion who underwent 24‐hour perfusion imaging from 2 international randomized controlled trials (EXTEND‐IA TNK part‐1 and 2) and a multicenter prospective observational study. Receiver‐operating‐characteristic and Bayesian‐information‐criterion (BIC) analyses were performed with the outcome variable being dependent‐or‐dead at 90‐days (modified Rankin Score [mRS] ≥3). Results: Of 131 patients analyzed, the prevalence of no‐reflow significantly varied between definitions (0.8–22.1%; p < 0.001). There was poor agreement between definitions (kappa 5/6 comparisons <0.212). Among patients with no‐reflow according to at least 1 definition, there were significant differences between definitions in the intralesional interside differences in cerebral blood flow (CBF) (p = 0.006), cerebral blood volume (CBV) (p < 0.001), and mean‐transit‐time (MTT) (p = 0.005). No‐reflow defined by 3 definitions was associated with mRS ≥3 at 90 days. The definition of >15% CBV or CBF asymmetry was the only definition that improved model fit on BIC analysis (ΔBIC = −8.105) and demonstrated an association between no‐reflow and clinical outcome among patients with eTICI3 reperfusion. Conclusions: Existing imaging definitions of no‐reflow varied significantly in prevalence and post‐treatment perfusion imaging profile, potentially explaining the variable prevalence of no‐reflow reported in literature. The definition of >15% CBV or CBF asymmetry best discriminated for functional outcome at 90 days, including patients with eTICI3 reperfusion. ANN NEUROL 2024;96:1104–1114 [ABSTRACT FROM AUTHOR]

Objective: To assess whether arterial spin labeling perfusion images of healthy controls can enhance ictal single‐photon emission computed tomography analysis and whether the acquisition of the interictal image can be omitted. Methods: We developed 2 pipelines: The first uses ictal and interictal images and compares these to single‐photon emission computed tomography and arterial spin labeling of healthy controls. The second pipeline uses only the ictal image and the analogous healthy controls. Both pipelines were compared to the gold standard analysis and evaluated on data of individuals with epilepsy who underwent ictal single‐photon emission computed tomography imaging during presurgical evaluation between 2010 and 2022. Fifty healthy controls prospectively underwent arterial spin labeling imaging. The correspondence between the detected hyperperfusion and the postoperative resection cavity or the presumably affected lobe was assessed using Dice score and mean Euclidean distance. Additionally, the outcomes of the pipelines were automatically assigned to 1 of 5 concordance categories. Results: Inclusion criteria were met by 43 individuals who underwent epilepsy surgery and by 73 non‐surgical individuals with epilepsy. Compared to the gold standard analysis, both pipelines resulted in significantly higher Dice scores and lower mean distances (p < 0.05). The combination of both provided localizing results in 85/116 cases, compared to 54/116 generated by the current gold standard analysis and the ictal image alone produced localizing results in 60/116 (52%) cases. Interpretation: We propose a new ictal single‐photon emission computed tomography protocol; it finds relevantly more ictal hyperperfusion, and halves the radiation dose in about half of the individuals. ANN NEUROL 2024;96:1160–1173 [ABSTRACT FROM AUTHOR]

PURPOSE: Limitations from commercial software applications prevent the implementation of a robust and cost-efficient high-throughput cancer imaging radiomic feature extraction and perfusion analysis workflow. This study aimed to develop and validate a cancer research computational solution using open-source software for vendor- and sequence-neutral high-throughput image processing and feature extraction. METHODS: The Cancer Radiomic and Perfusion Imaging (CARPI) automated framework is a Python-based software application that is vendor- and sequence-neutral. CARPI uses contour files generated using an application of the user's choice and performs automated radiomic feature extraction and perfusion analysis. This workflow solution was validated using two clinical data sets, one consisted of 40 pelvic chondrosarcomas and 42 sacral chordomas with a total of 82 patients, and a second data set consisted of 26 patients with undifferentiated pleomorphic sarcoma (UPS) imaged at multiple points during presurgical treatment. RESULTS: Three hundred sixteen volumetric contour files were processed using CARPI. The application automatically extracted 107 radiomic features from multiple magnetic resonance imaging sequences and seven semiquantitative perfusion parameters from time-intensity curves. Statistically significant differences (P <.00047) were found in 18 of 107 radiomic features in chordoma versus chondrosarcoma, including six first-order and 12 high-order features. In UPS postradiation, the apparent diffusion coefficient mean increased 41% in good responders (P =.0017), while firstorder_10Percentile (P =.0312) was statistically significant between good and partial/nonresponders. CONCLUSION: The CARPI processing of two clinical validation data sets confirmed the software application's ability to differentiate between different types of tumors and help predict patient response to treatment on the basis of radiomic features. Benchmark comparison with five similar open-source solutions demonstrated the advantages of CARPI in the automated perfusion feature extraction, relational database generation, and graphic report export features, although lacking a user-friendly graphical user interface and predictive model building. CARPI is a Python-based automated software application that enables radiomics and perfusion analysis of different types of tumors. [ABSTRACT FROM AUTHOR]

Perfusion dynamics play a vital role in delivering essential nutrients and oxygen to tissues while removing metabolic waste products. Imaging techniques such as magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET) use contrast agents to visualize perfusion and clearance patterns; however, each technique has specific limitations. Hybrid PET/MRI combines the quantitative power and sensitivity of PET with the high functional and anatomical detail of MRI and holds great promise for precision in molecular imaging. However, the development of dual PET/MRI probes has been hampered by challenging synthesis and radiolabeling. Here, we present a novel PET/MRI probe, [18F][Gd(FL1)], which exhibits excellent stability comparable to macrocyclic MRI contrast agents used in clinical practice. The unique molecular design of [18F][Gd(FL1)] allows selective and expeditious radiolabeling of the gadolinium chelate in the final synthetic step. Leveraging the strengths of MRI and PET signals, the probe enables quantitative in vivo mapping of perfusion and excretion dynamics through an innovative voxel‐based analysis. The diagnostic capabilities of [18F][Gd(FL1)] were demonstrated in a pilot study on healthy mice, successfully detecting early cases of unilateral renal dysfunction, a condition that is typically challenging to diagnose. This study introduces a new approach for PET/MRI and emphasizes a streamlined probe design for practical synthesis and improved diagnostic accuracy. [ABSTRACT FROM AUTHOR]

Introduction: Repeat imaging when regional and remote stroke patients arrive at a comprehensive stroke center (CSC) can delay endovascular thrombectomy (EVT). We examined which clinical and imaging parameters predict infarct progression and perfusion core growth during transport. Methods: We included patients recruited from 2017 to 2023 in a prospective database who were transferred from remote sites with large vessel occlusion, had CT perfusion imaging at the primary stroke center (PSC), and had repeat CT on arrival at the CSC demonstrating persistent occlusion. The key imaging characteristics were perfusion core change (rCBF < 30%) and ASPECTS change. Multiple and ordinal logistic regression analyses were used to assess the relationship between background clinical and imaging variables and the CT-perfusion core and ASPECTS on arrival. DEFUSE 3 criteria (ASPECTS ≥ 6, perfusion core < 70 mL) were used to define "favorable imaging." Results: In 90 patients with CT perfusion at both PSC and CSC and persistent occlusion, the median time from onset to PSC presentation was 279 min (IQR 143–702). The median time from PSC presentation to CSC arrival was 243.5 min (IQR 186–335), and the median distance traveled was 186.5 km (IQR 101–258). Lower baseline ASPECTS (per point) was associated with a 7 mL increase (95%CI 2–11 mL) in perfusion core between scans (p = 0.004). The time from onset, the time between PSC and CSC, and the distance traveled were not significantly associated with either ASPECTS or perfusion core growth during transport. In total, 11 out of 78 patients (14%) had deterioration of initially favorable imaging profiles during transport. Conclusion: Perfusion core growth during transport was uncommon and most strongly associated with lower ASPECTS at the PSC. Initially, favorable PSC imaging May predict whether repeat imaging is necessary at the CSC. [ABSTRACT FROM AUTHOR]

Coronary microvascular dysfunction is a clinical condition very diffuse in many different settings. Often the diagnosis can be very tricky, and choosing the proper diagnostic strategy can be fundamental for reaching the goal. The aim of this review is to evaluate the properties and the feasibility of our tests in specific scenarios by looking at the performances of each methodology reported in the literature. [ABSTRACT FROM AUTHOR]

Cardiovascular magnetic resonance imaging (MRI) in patients with cardiac implants, such as pacemakers and defibrillators, has gained importance in recent years with the development of modern cardiac implantable electronic devices. The increasing clinical need to perform MRI examinations in patients with cardiac implants has driven the development of new advanced MRI sequences to mitigate image artifacts associated with cardiac implants. More specifically, advances in imaging techniques, such as wideband late gadolinium enhancement imaging, wideband T1 mapping, and wideband perfusion, have been designed to improve image quality and examinations in patients with cardiac implants, enabling a comprehensive and more reliable diagnosis, which was previously unattainable in these patients. This review article explores recent developments and applications of wideband techniques in the field of cardiovascular MRI, offering insights into their transformative potential. Clinical applications of wideband cardiovascular MRI are highlighted, particularly in assessing myocardial viability, guiding ventricular tachycardia ablation, and characterizing myocardial tissue. [ABSTRACT FROM AUTHOR]

Perfusion changes in white matter (WM) lesions and normal‐appearing brain regions play an important pathophysiological role in multiple sclerosis (MS). However, most perfusion imaging methods require exogenous contrast agents, the repeated use of which is discouraged. Using resting‐state functional MRI (rs‐fMRI), we aimed to investigate differences in perfusion between white matter lesions and normal‐appearing brain regions in MS and healthy participants. A total of 41 MS patients and 41 age‐ and sex‐matched healthy participants received rs‐fMRI, from which measures of cerebral hemodynamics and oxygenation were extracted and compared across brain regions and study groups using within‐ and between‐group nonparametric tests, linear mixed models, and robust multiple linear regression. We found longer blood arrival times and lower blood volumes in lesions than in normal‐appearing WM. Higher blood volumes were found in MS patients' deep WM lesions compared to healthy participants, and blood arrival time was more delayed in MS patients' deep WM lesions than in healthy participants. Delayed blood arrival time in the cortical grey matter was associated with greater cognitive impairment in MS patients. Perfusion imaging using rs‐fMRI is useful for WM lesion characterization. rs‐fMRI‐based blood arrival times and volumes are associated with cognitive function. [ABSTRACT FROM AUTHOR]

Background and Purpose: Ischemic strokes due to isolated posterior cerebral artery (PCA) occlusions represent 5% of all strokes but have significant impacts on patients' quality of life, primarily due to visual deficits and thalamic involvement. Current guidelines for acute PCA occlusion management are sparse, and the prognostic value of perfusion imaging parameters remains underexplored. Methods: We conducted a retrospective analysis of 32 patients with isolated PCA occlusions treated at Johns Hopkins Medical Institutions between January 2017 and March 2023. Patients underwent pretreatment perfusion imaging, with perfusion parameters analyzed using RAPID software. The primary outcome was short‐term clinical outcome as measured by the National Institutes of Health Stroke Scale (NIHSS) at discharge. Results: The median age of the cohort was 70 years, with 34% female and 66% male. Significant correlations were found between NIHSS at discharge and various perfusion parameters, including time‐to‐maximum (Tmax) >6 seconds (ρ =.55, p =.004), Tmax >8 seconds (ρ =.59, p =.002), Tmax >10 seconds (ρ =.6, p =.001), mismatch volume (ρ =.51, p =.008), and cerebral blood volume (CBV) < 34% (ρ =.59, p =.002). Conclusions: Tmax and CBV volumes significantly correlated with discharge NIHSS with marginal superiority of Tmax >10 seconds and CBV <42% volumes. These findings suggest that CT and MR perfusion imaging can play a crucial role in the acute management of PCA strokes, though larger, standardized studies are needed to validate these results and refine imaging thresholds specific to posterior circulation infarcts. [ABSTRACT FROM AUTHOR]

Simple Summary: The spine is the most common site of osseous metastatic involvement. Advances in diagnosing and treating spinal metastasis have improved patient survival and quality of life. There is now a strong focus on customized imaging to enhance treatment planning for tumor ablation and reduce treatment-related complications. This review discusses imaging protocols and findings in the pre- and post-SBRT setting and the imaging features differentiating expected post-SBRT treatment changes from LF. Spine metastases (SMs) are common, arising in 70% of the cases of the most prevalent malignancies in males (prostate cancer) and females (breast cancer). Stereotactic body radiotherapy, or SBRT, has been incorporated into clinical treatment algorithms over the past decade. SBRT has shown promising rates of local control for oligometastatic spinal lesions with low radiation dose to adjacent critical tissues, particularly the spinal cord. Imaging is critically important in SBRT planning, guidance, and response monitoring. This paper reviews the roles of imaging in spine SBRT, including conventional and advanced imaging approaches for SM detection, treatment planning, and post-SBRT follow-up. [ABSTRACT FROM AUTHOR]

Purpose: Thrombolysis in Cerebral Infarction (TICI) 3 represents the optimal angiographic outcome following mechanical thrombectomy (MT) for acute ischemic stroke (AIS). Although it is known to yield better outcomes than TICI 2b, the influence of preprocedural cerebral hemodynamics on the clinical advantage of TICI 3 over TICI 2b remains unexplored. Methods: This single-center retrospective analysis involved patients with anterior circulation AIS who underwent successful recanalization during MT at the Comprehensive Stroke Center, University Hospital, Krakow between January 2019 and July 2023. We assessed the benefit of achieving TICI 2c/3 over TICI 2b on the basis of preprocedural computed perfusion imaging results, primarily focusing on early infarct volume (EIV) and tissue-level collaterals indicated by hypoperfusion intensity ratio (HIR). Good functional outcome (GFO) was defined as a modified Rankin Score < 3 on day 90. Results: The study comprised 612 patients, of whom 467 (76.3%) achieved TICI 2c/3. GFO was more frequent in the TICI 2c/3 group (54.5% vs 69.4%, p < 0.001). There was interaction between the recanalization status and both HIR (Pi = 0.042) and EIV (Pi = 0.012) in predicting GFO, with disproportionately higher impact of HIR and EIV in TICI 2b group. The benefit from TICI 2c/3 over TICI 2b was insignificant among patients with good collaterals, defined by HIR < 0.3 (odds ratio:1.36 [0.58–3.18], p = 0.483). Conclusion: TICI 2c/3 improves patient functional outcomes compared to TICI 2b regardless of EIV. However, such angiographic improvement may be clinically futile in patients with good tissue-level collateralization. Our findings suggest that preprocedural HIR should be considered when optimization of recanalization is considered during MT. [ABSTRACT FROM AUTHOR]

Purpose: Tumour perfusion is a nutrient-agnostic biomarker for cancer metabolic rate. Use of tumour perfusion for cancer growth assessment has been limited by complicated image acquisition, image analysis and limited field-of-view scanners. Long axial field-of-view (LAFOV) PET scan using [15O]H2O, allows quantitative assessment of whole-body tumour perfusion. We created a tool for automated creation of quantitative parametric whole-body tumour perfusion images in metastatic cancer. Methods: Ten metastatic prostate cancer patients underwent dynamic LAFOV [15O]H2O PET (Siemens, Quadra) followed by [18F]PSMA-1007 PET. Perfusion was measured as [15O]H2O K1 (mL/min/mL) with a single-tissue compartment model and an automatically captured cardiac image-derived input function. Parametric perfusion images were automatically calculated using the basis-function method with initial voxel-wise delay estimation and a leading-edge approach. Subsequently, perfusion of volumes-of-interest (VOI) can be directly extracted from the parametric images. We used a [18F]PSMA-1007 SUV 4 fixed threshold for tumour delineation and transferred these VOIs to the perfusion map. Results: For 8 primary tumours, 64 lymph node metastases, and 85 bone metastases, median tumour perfusion were 0.19 (0.15–0.27) mL/min/mL, 0.16 (0.13–0.27) mL/min/mL, and 0.26 (0.21–0.39), respectively. The correlation between calculated perfusion from time-activity-curves and parametric images was excellent (r = 0.99, p < 0.0001). Conclusion: LAFOV PET imaging using [15O]H2O enables truly quantitative parametric images of whole-body tumour perfusion, a potential biomarker for guiding personalized treatment and monitoring treatment response. [ABSTRACT FROM AUTHOR]

Purpose: To mitigate the B0/B1+ sensitivity of velocity‐selective inversion (VSI) pulse trains for velocity‐selective arterial spin labeling (VSASL) by implementing adiabatic refocusing. This approach aims to achieve artifact‐free VSI‐based perfusion imaging through single‐pair label‐control subtractions, reducing the need for the currently required four‐pair dynamic phase‐cycling (DPC) technique when using a velocity‐insensitive control. Methods: We introduce a Fourier‐transform VSI (FT‐VSI) train that incorporates sinc‐modulated hard excitation pulses with MLEV‐8‐modulated adiabatic hyperbolic secant refocusing pairs. We compare performance between this train and the standard composite refocusing train, including with and without DPC, for dual‐module VSI VSASL. We evaluate (1) simulated velocity‐selective profiles and subtraction fidelity across a broad B0/B1+ range, (2) subtraction fidelity in phantoms, and (3) image quality, artifact presence, and gray‐matter perfusion heterogeneity (as measured by the spatial coefficient of variation) in healthy human subjects. Results: Adiabatic refocusing significantly improves FT‐VSI robustness to B0/B1+ inhomogeneity for a single label‐control subtraction. Subtraction fidelity is dramatically improved in both simulation and phantoms compared with composite refocusing without DPC, and is similar compared with DPC methods. In humans, marked artifacts seen with the non‐DPC composite refocusing approach are eliminated, corroborated by significantly reduced gray‐matter heterogeneity (via lower spatial coefficient of variation values). Conclusion: A novel VSASL labeling train using adiabatic refocusing pulses for VSI was found to reduce artifacts related to B0/B1+ inhomogeneity, thereby providing an alternative to DPC and its associated limitations, which include increased vulnerability to physiological noise and motion, reduced functional MRI applicability, and suboptimal data censoring. [ABSTRACT FROM AUTHOR]

Introduction: Pulmonary transit time (PTT) is the time it takes blood to pass from the right ventricle to the left ventricle via the pulmonary circulation, making it a potentially useful marker for heart failure. We assessed the association of PTT with diastolic dysfunction (DD) and mitral valve regurgitation (MVR). Methods: We evaluated routine stress perfusion cardiovascular magnetic resonance (CMR) scans in 83 patients including assessment of PTT with simultaneously available echocardiographic assessment. Relevant DD and MVR were defined as exceeding Grade I (impaired relaxation and mild regurgitation). PTT was determined from CMR rest perfusion scans. Normalized PTT (nPTT), adjusted for heart rate, was calculated using Bazett's formula. Results: Higher PTT and nPTT values were associated with higher grade DD and MVR. The diagnostic accuracy for the prediction of DD as quantified by the area under the ROC curve (AUC) was 0.73 (CI 0.61–0.85; p = 0.001) for PTT and 0.81 (CI 0.71–0.89; p < 0.001) for nPTT. For MVR, the diagnostic performance amounted to an AUC of 0.80 (CI 0.68–0.92; p < 0.001) for PTT and 0.78 (CI 0.65–0.90; p < 0.001) for nPTT. PTT values < 8 s rule out the presence of DD and MVR with a probability of 70% (negative predictive value 78%). Conclusion: CMR‐derived PTT is a readily obtainable hemodynamic parameter. It is elevated in patients with DD and moderate to severe MVR. Low PTT values make the presence of DD and MVR—as assessed by echocardiography—unlikely. [ABSTRACT FROM AUTHOR]

Objective Methods Results Interpretation About 25% of patients with acute ischemic stroke (AIS) present within the intravenous thrombolytic (IVT) therapeutic window of <4.5 h. This study is to elucidate the safety and efficacy of IVT in the extended therapeutic window (ETW) in patients with AIS.Using PRISMA guidelines, a systematic review was conducted using PubMed, Embase, and Scopus. A rigorous risk of bias assessment was conducted using the RoB2 tool. Rates of excellent and good functional outcome (mRS 0–1 and mRS 0–2) at 90 days, symptomatic intracranial hemorrhage (sICH), and mortality at 90 days were pooled using generalized linear mixed model and compared with controls. Meta‐analyses were conducted employing random‐effect models with risk ratio (RR) and 95% confidence intervals (CIs). Subgroup analysis was performed to assess the effect of imaging modalities used for patient selection.Eight randomized controlled trials (n = 2221, 59% male) were included. At 90 days IVT showed higher rates of functional recovery: mRS 0–1: RR 1.21 95% CI 1.1–1.34, p < 0.001, and mRS 0–2: RR 1.11 95% CI 1.03–1.18, p = 0.004. Rate of mortality at 90 day was not different between groups: RR 1.17 95% CI 0.93–1.48, p = 0.17. However, the rate of sICH was higher among IVT group: RR 2.93 95% CI 1.53–5.6, p = 0.001. Subgroup analysis showed higher mRS 0–1 among patients who were selected based on perfusion imaging (p < 0.05).The use of IVT in AIS in ETW is beneficial especially with the use of perfusion imaging for patients' selection. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions While advances in endovascular thrombectomy (EVT) have led to high reperfusion rates, most patients treated with EVT do not avoid disability. Post‐reperfusion hemorrhagic transformation (HT) is a potential target for improving outcomes. This study examined pretreatment blood–brain barrier (BBB) disruption in tissue that would subsequently become part of the final infarct to evaluate its role in post‐EVT HT.This post hoc analysis of the FRAME study, which enrolled patients with anterior large vessel occlusion who received EVT within 6 hours of onset, included patients if they had successful pretreatment MRI perfusion weighted imaging (PWI) and underwent successful EVT. BBB disruption was measured as the percent signal change due to gadolinium leakage on the PWI source images prior to thrombectomy. Mean permeability derangement (MPD) was defined as the average of all voxels in the stroke core that are two standard deviations above normal. The primary outcome was hemorrhagic transformation with parenchymal hematoma (PH).In total, 164 patients were included; mean age was 71 and 48% were female. PH occurred in 57 patients. Median MPD was 13.5% for patients with PH versus 3.6% for patients without (p < 0.0001). Elevated MPD was independently associated with PH with a 20% increased risk of PH for each 5% increase in MPD (OR 1.206; 95% CI 1.037:1.405; p = 0.0147, adjusted for NIHSS and procedure duration).Even in patients who are successfully recanalized in an early time window, pretreatment BBB disruption in regions that go on to infarct is associated with an increased risk of post‐EVT HT. [ABSTRACT FROM AUTHOR]

Introduction: In multiplexed positron emission tomography (mPET) imaging, physiological and pathological information from different radiotracers can be observed simultaneously in a single dynamic PET scan. The separation of mPET signals within a single PET scan is challenging due to the fact that the PET scanner measures the sum of the PET signals of all the tracers. The conventional multitracer compartment modeling (MTCM) method requires staggered injections and assumes that the arterial input functions (AIFs) of each tracer are known. Methods: In this work, we propose a deep learning-based method to separate triple-tracer PET images without explicitly knowing the AIFs. A dynamic tripletracer noisy MLEM reconstruction was used as the network input, and dynamic single-tracer noisy MLEM reconstructions were used as training labels. Results: A simulation study was performed to evaluate the performance of the proposed framework on triple-tracer ([18F]FDG+82Rb+[94mTc]sestamibi) PET myocardial imaging. The results show that the proposed methodology substantially reduced the noise level compared to the results obtained from single-tracer imaging. Additionally, it achieved lower bias and standard deviation in the separated single-tracer images compared to the MTCM-based method at both the voxel and region of interest (ROI) levels. Discussion: As compared to MTCM separation, the proposed method uses spatiotemporal information for separation, which improves the separation performance at both the voxel and ROI levels. The simulation study also demonstrates the feasibility and potential of the proposed DL-based method for the application to pre-clinical and clinical studies. [ABSTRACT FROM AUTHOR]

Objective: To observe the effects of xuesaitai combined with acupuncture and head scraping on cerebral CT perfusion imaging indexes, hemorheology and platelet-leukocyte aggregates in patients with convalescent cerebral infarction. Methods: 120 patients with convalescent cerebral infarction of wind-phlegm blocking collaterals type were divided into groups A, B, C, D, E and F according to the random number table method, with 20 cases in each group. The cerebral CT perfusion imaging indexes, hemorheology indexes and platelet-leukocyte aggregates were compared before and after treatment in six groups. Results: Compared with group A, the mean transit time (MTT), platelet monocyte aggregation (PMA), whole blood low shear viscosity, platelet leukocyte aggregation (PLA), whole blood high shear viscosity, platelet neutrophil aggregation (PNA), plasma viscosity, platelet lymphocyte aggregation (PlyA) were lower in group B, group C, group D, group E and group F after treatment, and local cerebral blood flow (rCBF) and local cerebral blood volume (rCBV) were higher (P<0.05). The indexes in group D, group E and group F were better than those in group B and group C (P<0.05), and the indexes in group F were the best after treatment (P<0.05). Conclusion: Xuesaitai combined with acupuncture and head scraping in the treatment of convalescent patients with wind-phlegm blocking collaterals type cerebral infarction, which can improve cerebral CT perfusion imaging indexes, platelet-leukocyte aggregates and hemorheology. [ABSTRACT FROM AUTHOR]

Background: Technetium-99 m-labelled macroaggregated human serum albumin ([99mTc]Tc-MAA) is commonly used for lung perfusion scintigraphy. The European Pharmacopoeia (Eu.Ph.) specifies thin-layer chromatography (TLC) as the only method to assess its radiochemical purity (RCP). Similarly, TLC is the sole method reported in the literature to evaluate the RCP of Gallium-68-labelled MAA [68 Ga]Ga-MAA, recently introduced for lung perfusion PET/CT imaging. Since [68 Ga]Ga-MAA is prepared from commercial kits originally designed for the preparation of [99mTc]Tc-MAA, it is essential to optimize and validate the preparation methods for [68 Ga]Ga-MAA. Results: We tested a novel, simplified method for the preparation of [68 Ga]Ga-MAA that does not require organic solvents, prewash or final purification steps to remove radioactive impurities. We assessed the final product using radio-TLC, radio-UV-HPLC, and radio SDS-PAGE. Overall, our quality control (QC) method successfully detected [68 Ga]Ga-MAA along with all potential impurities, including free Ga-68, [68 Ga]Ga-HSA, unlabeled HSA, which may occur during labelling process and HEPES residual, a non-toxic but non-human-approved contaminant, used as buffer solution. We then applied our QC system to [68 Ga]Ga-MAA prepared under different conditions (25°–40°–75°–95 °C), thus defining the optimal temperature for labelling. Scanning Electron Microscopy (SEM) analysis of the products obtained through our novel method confirmed that most [68 Ga]Ga-MAA particles preserved the morphological structure and size distribution of unlabeled MAA, with a particle diameter range of 25–50 μm, assuring diagnostic efficacy. Conclusions: We optimized a novel method to prepare [68 Ga]Ga-MAA through a QC system capable of monitoring all impurities of the final products. [ABSTRACT FROM AUTHOR]

Background: Gastric cancer stands as one of the most prevalent malignancies globally, conventional endoscopic specimens have been the primary means of diagnosing preoperative gastric histopathology, however, their limitations in capturing intra-tumor heterogeneity compromise their efficacy in evaluating angiogenesis. Perfusion Computed Tomography (P-CT) emerges as a pivotal functional imaging modality, facilitating objective assessment of tissue perfusion, serving as a marker of angiogenesis. So, our research objective was to evaluate the efficacy of CT perfusion imaging in the prediction of histological grades of gastric tumors using quantitative perfusion parameters such as permeability surface (PS), blood flow (BF), mean transient time (MTT), and blood volume (BV), in addition to the qualitative scoring system then comparing the findings with the histopathological results. Results: PS and BF were statistically significant predictors of the grade of differentiation, their odds ratio (OR) was (1.05, 95% CI 1.02–1.09, for each of them) (P = 0.004, P = 0.009, respectively). MTT also emerged as a significant predictor of the grade of differentiation with an OR of 0.76 (95% CI 0.57–0.93, P = 0.025). Using multivariate logistic regression model, PS was the most potent individual P-CT predictor of differentiation of the grade and the diagnosis of poorly differentiated tumors at ≥ 39 mL/100 g/min cut off point, followed by BF at ≥ 82.2 mL/100 g/min, and MTT at < 8.4 s. Regarding the qualitative scoring system P-CT, poorly differentiated tumors generally received higher scores of PS (P < 0.001), BF (P < 0.001), and BV (P = 0.017), than well and moderately differentiated tumors, however, MTT showed that poorly differentiated tumors were more frequently scored as low compared to well and moderately differentiated tumors (P < 0.001). Conclusions: P-CT is an innovative, non-invasive biomarker for predicting gastric cancer grade by quantitative and qualitative assessment by P-CT parameters (PS, BF and MTT) with particular role of PS as the strongest individual P-CT predictor of differentiation grade followed by BF and MTT at specific cut off points. [ABSTRACT FROM AUTHOR]

BACKGROUND: Coronary microvascular dysfunction has been implicated in the development of hypertensive heart disease and heart failure, with subendocardial ischemia identified as a driver of sustained myocardial injury and fibrosis. We aimed to evaluate the relationships of subendocardial perfusion with cardiac injury, structure, and a composite of major adverse cardiac and cerebrovascular events consisting of death, heart failure hospitalization, myocardial infarction, and stroke. METHODS: Layer-specific blood flow and myocardial flow reserve (MFR; stress/rest myocardial blood flow) were assessed by 13N-ammonia perfusion positron emission tomography in consecutive patients with hypertension without flow-limiting coronary artery disease (summed stress score <3) imaged at Brigham and Women's Hospital (Boston, MA) from 2015 to 2021. In this post hoc observational study, biomarkers, echocardiographic parameters, and longitudinal clinical outcomes were compared by tertiles of subendocardial MFR (MFRsubendo). RESULTS: Among 358 patients, the mean age was 70.6±12.0 years, and 53.4% were male. The median MFRsubendo was 2.57 (interquartile range, 2.08-3.10), and lower MFRsubendo was associated with older age, diabetes, lower renal function, greater coronary calcium burden, and higher systolic blood pressure (P<0.05 for all). In cross-sectional multivariable regression analyses, the lowest tertile of MFRsubendo was associated with myocardial injury and with greater left ventricular wall thickness and volumes compared with the highest tertile. Relative to the highest tertile, low MFRsubendo was independently associated with an increased rate of major adverse cardiac and cerebrovascular events (adjusted hazard ratio, 2.99 [95% CI, 1.39-6.44]; P=0.005) and heart failure hospitalization (adjusted hazard ratio, 2.76 [95% CI, 1.04-7.32; P=0.042) over 1.1 (interquartile range, 0.6-2.8) years median follow-up. CONCLUSIONS: Among patients with hypertension without flow-limiting coronary artery disease, impaired MFRsubendo was associated with cardiovascular risk factors, elevated cardiac biomarkers, cardiac structure, and clinical events. [ABSTRACT FROM AUTHOR]

Introduction: While increased baseline blood pressure (BP) is a prevalent comorbidity in the acute phase of ischemic stroke, the association between baseline BP and the state of hemispheric perfusion in patients with acute small subcortical infarcts (SSIs) has not been studied in detail. The aim of this study was to investigate the relationship between baseline BP and hemispheric cerebral blood flow (CBF) in acute SSIs. Methods: This retrospective study included 101 patients with acute SSIs. Baseline hemispheric CBF was assessed through co-registration of baseline CT perfusion imaging and follow-up diffusion-weighted imaging. The association between baseline BP, CBF, and different cerebral small vessel disease (CSVD) biomarkers was assessed. Results: Baseline systolic BP (SBP) and diastolic BP (DBP) were negatively associated with contralateral hemispheric CBF after multivariate-adjusted linear analysis (SBP: β = −0.001, 95% CI: −0.002 to 0.000, p = 0.030; DBP: β = −0.002, 95% CI: −0.003∼0.001, p = 0.006). Among other CSVD biomarkers, the presence of any cerebral microbleeds showed a significant association with lower CBF in the contralateral hemisphere of the infarct lesion (r = −0.270, p = 0.035). Conclusion: In patients with acute SSIs, increased baseline BP was associated with reduced CBF in the contralateral hemisphere of the infarct lesion, which probably could be interpreted by the exacerbation of the CSVD burden, suggesting a potential mechanistic link between BP autoregulation dysfunction and the aggravation of neurovascular impairment in SSIs. [ABSTRACT FROM AUTHOR]

Purpose • Angiogenesis, the formation of new blood vessels, plays a crucial role in tumor growth and metastasis. Understanding the vascular characteristics of colorectal cancer through preoperative computed tomography (CT) perfusion parameters can provide valuable insights into the tumor’s aggressiveness and potential for spread. Additionally, exploring the correlation between these parameters and serum tumor marker levels may offer a comprehensive perspective on the disease’s biological behavior. Methods • In this retrospective study, we investigated 42 colorectal cancer patients. Based on microvascular density (MVD) measured by immunohistochemistry (IHC), participants were categorized into either a high-density group (n = 24) with MVD ≥ 35/field of view or a low-density group (n = 18) with MVD < 35/field of view. Additionally, a control group comprised 25 patients with pathologically confirmed benign colorectal lesions. This study design allowed us to assess the correlation between MVD and colorectal cancer, differentiating between high and low microvascular density groups, while also comparing results to a control group for comprehensive analysis. Results • Colorectal cancer was associated with significantly higher levels of blood volume (BV; high-density group: 7.65±1.36 mL/100g; low-density group: 6.73±1.29 mL/100g), blood flow (BF; high-density group: 67.33±12.16 ml/(100g·min); low-density group: 52.84±11.43 ml/ (100g·min)), permeability surface (PS; high-density group: 35.19±6.32 ml/(100g·min); low-density group: 22.27±4.85 ml/(100g·min)), serum glycoprotein antigen 19-9 (CA19-9; high-density group: 45.38±5.41 g/ ml); low-density group: 23.43±3.59 g/ml), glycoprotein antigen 125 (CA125; high-density group: 27.56±3.73 g/ml); low-density group: 12.63±2.59 g/ml), and carcinoembryonic antigen (CEA; high-density group: 17.87±3.12 g/ml); low-density group: 8.51±2.87 g/ml) versus benign colorectal lesions, with more significant changes observed in the high-density group versus the low-density group (P ≤ .001). The three groups showed similar mean transit time (MTT). The AUCs under the ROC curves for BV, BF, PS, and TTP were 0.901, 0.898, 0.963, and 0.983, respectively. Pearson correlation analysis showed a positive correlation of patients’ serum CA19-9 with BV, BF, and PS., Serum CA125 and CEA were positively correlated with BF and PS, and the above indicators were negatively correlated with TTP. Conclusions • In conclusion, our study highlights the potential of preoperative CT perfusion imaging as a valuable tool for evaluating angiogenesis in colorectal cancer and its correlation with serum tumor markers. The identified associations open avenues for further research to delve into specific aspects of angiogenesis and tumor markers. Future investigations could focus on elucidating the molecular mechanisms underlying the observed correlations, potentially identifying novel therapeutic targets. Additionally, exploring the dynamic changes in angiogenesis and tumor markers during different stages of colorectal cancer progression may provide a more comprehensive understanding. Moreover, assessing the prognostic value of these imaging and biomarker correlations in larger, diverse patient cohorts could enhance their clinical utility. Our findings lay the groundwork for these future research directions, emphasizing the need for continued exploration to advance our knowledge and improve clinical strategies for colorectal cancer management. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to investigate whether the spatial coefficient of variation of arterial spin labeling (ASL-CoV) acquired in clinical settings can be used to estimate decreased cerebrovascular reactivity (CVR) measured with single-photon emission computed tomography (SPECT) and acetazolamide challenge in patients with atherosclerotic stenosis of intra- or extracranial arteries. Methods: We evaluated the data of 27 atherosclerotic stenosis patients who underwent pseudocontinuous ASL and SPECT. After spatial normalization, regional values were measured using the distributed middle cerebral artery territorial atlas of each patient. We performed comparisons, correlations, and receiver operating characteristic (ROC) curve analyses between ASL-cerebral blood blow (CBF), ASL-CoV, SPECT-CBF and SPECT-CVR. Results: Although the ASL-CBF values were positively correlated with SPECT-CBF values (r = 0.48, 95% confidence interval (CI) = 0.28–0.64), no significant difference in ASL-CBF values was detected between regions with and without decreased CVR. However, regions with decreased CVR had significantly greater ASL-CoV values than regions without decreased CVR. SPECT-CVR was negatively correlated with ASL-CoV (ρ = -0.29, 95% CI = -0.49 - -0.06). The area under the ROC curve of ASL-CoV in predicting decreased CVR (0.66, 95% CI = 0.51–0.81) was greater than that of ASL-CBF (0.51, 95% CI = 0.34–0.68). An ASL-CoV threshold value of 42% achieved a high specificity of 0.93 (sensitivity = 0.42, positive predictive value = 0.77, and negative predictive value = 0.75). Conclusion: ASL-CoV acquired by single postlabeling delay without an acetazolamide challenge may aid in the identification of patients with decreased CVR on SPECT. [ABSTRACT FROM AUTHOR]

Introduction: We aimed to investigate the performance of several neuroimaging markers provided by perfusion imaging of Acute Ischemic Stroke (AIS) patients with large vessel occlusion (LVO) in order to predict clinical outcomes following reperfusion treatments. Methods: We prospectively evaluated consecutive AIS patients with LVO who were treated with reperfusion therapies, during a six-year period. In order to compare patients with good (mRS scores 0–2) and poor (mRS scores 3–6) functional outcomes, data regarding clinical characteristics, the Alberta Stroke Programme Early Computed Tomography Score (ASPECTS) based on unenhanced computed tomography (CT), CT angiography collateral status and perfusion parameters including ischemic core, hypoperfusion volume, mismatch volume between core and penumbra, Tmax > 10 s volume, CBV index and the Hypoperfusion Index Ratio (HIR) were assessed. Results: A total of 84 acute stroke patients with LVO who met all the inclusion criteria were enrolled. In multivariable logistic regression models increasing age (odds ratio [OR]: 0.93; 95%CI: 0.88–0.96, p = 0.001), lower admission National Institute of Health Stroke Scale (NIHSS)-score (OR: 0.88; 95%CI: 0.80–0.95, p = 0.004), pretreatment with intravenous thrombolysis (OR: 3.83; 95%CI: 1.29–12.49, p = 0.019) and HIR (OR:0.36; 95%CI: 0.10–0.95, p = 0.042) were independent predictors of good functional outcome at 3 months. The initial univariable associations between HIR and higher likelihood for symptomatic intracranial hemorrhage (sICH) and parenchymal hematoma type 2 (PH2) were attenuated in multivariable analyses failing to reach statistical significance. Discussion: Our pilot observational study of unselected AIS patients with LVO treated with reperfusion therapies demonstrated that pre-treatment low HIR in perfusion imaging and IVT were associated with better functional outcomes. [ABSTRACT FROM AUTHOR]

We sought to investigate the impact of sex on myocardial perfusion changes following chronic total coronary occlusion (CTO) percutaneous coronary intervention (PCI) as measured by [15O]H 2 O positron-emission tomography (PET) perfusion imaging. CTO PCI has been associated with an increase in myocardial perfusion, yet females are less likely to undergo revascularization. As such, data on the impact of sex on myocardial perfusion following CTO PCI is scarce. A total of 212 patients were prospectively enrolled and underwent CTO PCI combined with [15O]H 2 O PET perfusion imaging prior to and 3 months after PCI. Hyperemic myocardial blood flow (hMBF, mL·min−1·g−1) and coronary flow reserve (CFR) allocated to the CTO territory were quantitatively assessed. This study comprised 34 (16 %) females and 178 (84 %) males. HMBF at baseline did not differ between sexes. Females showed a higher increase in hMBF than males (Δ1.34 ± 0.67 vs. Δ1.06 ± 0.74, p = 0.044), whereas post-PCI hMBF was comparable (2.59 ± 0.85 in females vs. 2.28 ± 0.84 in males, p = 0.052). Female sex was independently associated with a higher increase in hMBF after correction for clinical covariates. CFR increase after revascularization was similar in females and males (Δ1.47 ± 0.99 vs. Δ1.30 ± 1.14, p = 0.711). The present study demonstrates a greater recovery of stress perfusion in females compared to males as measured by serial [15O]H 2 O PET imaging. In addition, a comparable increase in CFR was found in females and males. These results emphasize the benefit of performing CTO PCI in both sexes. What is new? • CTO PCI has been associated with an increase in myocardial perfusion, yet females are less likely to undergo revascularization. • We found a greater recovery of stress perfusion in females compared to males after CTO PCI as measured by serial [15O]H 2 O PET imaging, whereas coronary flow reserve was comparable between sexes. • The present study adds to the limited body of evidence on the impact of sex on myocardial perfusion following CTO PCI. What are the clinical implications? • Our findings suggest that recovery of myocardial perfusion following CTO PCI is achievable in both female and male patients. • These results underscore the need to adhere to current guidelines for optimal CTO management in both sexes. • Future studies with standardized preprocedural imaging are warranted to increase our understanding of the impact of sex on changes in myocardial perfusion following CTO PCI. • CTO PCI is associated with an increase in myocardial perfusion, yet females are less likely to undergo revascularization. • We found a greater recovery of stress perfusion in females after CTO PCI as measured by serial [15O]H 2 O PET imaging. • Our findings suggest that recovery of myocardial perfusion following CTO PCI is achievable in both female and male patients. • These results underscore the need to adhere to current guidelines for optimal CTO management in both sexes. • Studies with preprocedural imaging are warranted to increase our understanding of the impact of sex on MBF after CTO PCI. [ABSTRACT FROM AUTHOR]

Purpose: To compare the diagnostic approach of acute pulmonary embolism (PE) with photon-counting-detector CT (PCD-CT) and energy-integrating-detector CT (EID-CT). Materials and methods: Two cohorts underwent CT angiographic examinations with EID-CT (Group 1; n = 158) and PCD-CT (Group 2; n = 172), (b) with two options in Group 1, dual energy (Group 1a) or single energy (Group 1b) and a single option in Group 2 (spectral imaging with single source). Results: In Group 2, all patients benefited from spectral imaging, only accessible to 105 patients (66.5%) in Group 1, with a mean acquisition time significantly shorter (0.9 ± 0.1 s vs 4.0 ± 0.3 s; p < 0.001) and mean values of CTDIvol and DLP reduced by 46.3% and 47.7%, respectively. Comparing the quality of 70 keV (Group 2) and averaged (Group 1a) images: (a) the mean attenuation within pulmonary arteries did not differ (p = 0.13); (b) the image noise was significantly higher (p < 0.001) in Group 2 with no difference in subjective image noise (p = 0.29); and (c) 89% of examinations were devoid of artifacts in Group 2 vs 28.6% in Group 1a. The percentage of diagnostic examinations was 95.2% (100/105; Group 1a), 100% (53/53; Group 1b), and 95.3% (164/172; Group 2). There were 4.8% (5/105; Group 1a) and 4.7% (8/172; Group 2) of non-diagnostic examinations, mainly due to the suboptimal quality of vascular opacification with the restoration of a diagnostic image quality on low-energy images. Conclusion: Compared to EID-CT, morphology and perfusion imaging were available in all patients scanned with PCD-CT, with the radiation dose reduced by 48%. Clinical relevance statement: PCD-CT enables scanning patients with the advantages of both spectral imaging, including high-quality morphologic imaging and lung perfusion for all patients, and fast scanning—a combination that is not simultaneously accessible with EID-CT while reducing the radiation dose by almost 50%. Key Points: The complementarity between morphology and perfusion imaging is accessible in each PCD-CT examination. High-quality images are obtained with PCD-CT in all categories of patients, including dyspneic patients. PCD-CT enables about 50% radiation dose reduction compared with EID-CT. [ABSTRACT FROM AUTHOR]

Background: Hypertension‐induced impairment of the cerebral artery network contributes to cognitive impairment. Characterizing the structure and function of cerebral arteries may facilitate the understanding of hypertension‐related pathological mechanisms and lead to the development of new indicators for cognitive impairment. Purpose: To investigate the associations between morphological features of the intracranial arteries distal to the circle of Willis on time‐of‐flight MRA (TOF‐MRA) and cognitive performance in a hypertensive cohort. Study Type: Prospective observational study. Population: 189 hypertensive older males (mean age 64.9 ± 7.2 years). Field Strength/Sequence: TOF‐MRA sequence with a 3D spoiled gradient echo readout and arterial spin labeling perfusion imaging sequence with a 3D stack‐of‐spirals fast spin echo readout at 3T. Assessment: The intracranial arteries were segmented from TOF‐MRA and the total length of distal arteries (TLoDA) and number of arterial branches (NoB) were calculated. The mean gray matter cerebral blood flow (GM‐CBF) was extracted from arterial spin labeling perfusion imaging. The cognitive level was assessed with short‐term and long‐term delay‐recall auditory verbal learning test (AVLT) scores, and with montreal cognitive assessment. Statistical Tests: Univariable and multivariable linear regression were used to analyze the associations between TLoDA, NoB, GM‐CBF and the cognitive assessment scores, with P < 0.05 indicating significance. Results: TLoDA (r = 0.314) and NoB (r = 0.346) were significantly correlated with GM‐CBF. Multivariable linear regression analyses showed that TLoDA and NoB, but not GM‐CBF (P = 0.272 and 0.141), were significantly associated with short‐term and long‐term delay‐recall AVLT scores. These associations remained significant after adjusting for GM‐CBF. Data Conclusion: The TLoDA and NoB of distal intracranial arteries on TOF‐MRA are significantly associated with cognitive impairment in hypertensive subjects. Level of Evidence: 2 Technical Efficacy: Stage 3 [ABSTRACT FROM AUTHOR]

Arterial spin labeling (ASL) is a noninvasive imaging technique that labels the proton spins in arterial blood and uses them as endogenous tracers. Brain perfusion imaging with ASL is becoming increasingly common in clinical practice, and clinical applications of ASL for intracranial magnetic resonance angiography (MRA) have also been demonstrated. Unlike computed tomography (CT) angiography and cerebral angiography, ASL‐based MRA does not require contrast agents. ASL‐based MRA overcomes most of the disadvantages of time‐of‐flight (TOF) MRA. Several schemes have been developed for ASL‐based MRA; the most common method has been pulsed ASL, but more recently pseudo‐continuous ASL, which provides a higher signal‐to‐noise ratio (SNR), has been used more frequently. New methods that have been developed include direct intracranial labeling methods such as velocity‐selective ASL and acceleration‐selective ASL. MRA using an extremely short echo time (eg, silent MRA) or ultrashort echo‐time (TE) MRA can suppress metal susceptibility artifacts and is ideal for patients with a metallic device implanted in a cerebral vessel. Vessel‐selective 4D ASL MRA can provide digital subtraction angiography (DSA)‐like images. This review highlights the principles, clinical applications, and characteristics of various ASL‐based MRA techniques. Level of Evidence: 5 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Background: Clinically relevant‐postoperative pancreatic fistula (CR‐POPF) is one of the dreaded complications of pancreatoduodenectomy. Vascularity of the stump of the pancreas during pancreatico‐enteric anastomosis is considered one of the major determinants of POPF. Indocyanine green (ICG) is one of the modality for vascular assessment; hence, we aimed to evaluate the role of ICG fluorescence imaging to assess the vascularity of the pancreatic stump during pancreatoduodenectomy. Methodology: The study was conducted at Kathmandu Medical College, Kathmandu, Nepal, during the period of 1 year (June 01, 2022–July 31, 2023). All of the patients who were undergoing pancreatoduodenectomy were included in the study. In all cases, intraoperatively, ICG fluorescence detection at the pancreatic stump margin was evaluated using near‐infrared light. Results: A total of 28 patients underwent PD during this period. The ICG fluorescence imaging was positive at the pancreatic stump margin in 25 out of the 28 patients (89%), and in three cases, the florescence was negative. In patients who had negative fluorescence, revision of the stump margin was performed. Clinically relevant POPF was noted in 2 out of 28 cases, which had a soft pancreas with a small duct, although the pancreatic stump margin had good ICG florescence per‐operatively. Conclusion: ICG is inexpensive and a safe dye to use in clinical practice. We can objectively assess the pancreatic stump vascularity using intraoperative ICG fluorescence imaging, thereby potentially decreasing postoperative pancreatic fistula. [ABSTRACT FROM AUTHOR]

Purpose: To improve the spatial resolution and repeatability of a non‐contrast MRI technique for simultaneous time resolved 3D angiography and perfusion imaging by developing an efficient 3D cone trajectory design. Methods: A novel parameterized 3D cone trajectory design incorporating the 3D golden angle was integrated into 4D combined angiography and perfusion using radial imaging and arterial spin labeling (CAPRIA) to achieve higher spatial resolution and sampling efficiency for both dynamic angiography and perfusion imaging with flexible spatiotemporal resolution. Numerical simulations and physical phantom scanning were used to optimize the cone design. Eight healthy volunteers were scanned to compare the original radial trajectory in 4D CAPRIA with our newly designed cone trajectory. A locally low rank reconstruction method was used to leverage the complementary k‐space sampling across time. Results: The improved sampling in the periphery of k‐space obtained with the optimized 3D cone trajectory resulted in improved spatial resolution compared with the radial trajectory in phantom scans. Improved vessel sharpness and perfusion visualization were also achieved in vivo. Less dephasing was observed in the angiograms because of the short TE of our cone trajectory and the improved k‐space sampling efficiency also resulted in higher repeatability compared to the original radial approach. Conclusion: The proposed 3D cone trajectory combined with 3D golden angle ordering resulted in improved spatial resolution and image quality for both angiography and perfusion imaging and could potentially benefit other applications that require an efficient sampling scheme with flexible spatial and temporal resolution. [ABSTRACT FROM AUTHOR]

Aims This study aimed to assess the impact of adenosine on quantitative myocardial blood flow (MBF) in a rapid stress–rest protocol compared with a rest–stress protocol using 13N-ammonia positron emission tomography (PET) myocardial perfusion imaging (MPI) and to gain insights into the time dependency of such effects. Methods and results Quantitative MBF at rest (rMBF) and during adenosine-induced stress (sMBF) and myocardial flow reserve (MFR) were obtained from 331 retrospectively identified patients who underwent 13N-ammonia PET MPI for suspected chronic coronary syndrome and who all exhibited no perfusion defects. Of these, 146 (44.1%) underwent a rapid stress–rest protocol with a time interval (Δ t stress–rest) of 20 ± 4 min between adenosine infusion offset and rest imaging, as per clinical routine. The remaining 185 (55.9%) patients underwent a rest–stress protocol and served as the reference. Groups did not differ regarding demographics, risk factors, medication, left ventricular function, and calcium scores. rMBF was significantly higher in the stress–rest vs. the rest–stress group [0.80 (interquartile range 0.66–1.00) vs. 0.70 (0.58–0.83) mL·min−1·g−1, P < 0.001], and, as sMBF was identical between groups [2.52 (2.20–2.96) vs. 2.50 (1.96–3.11), P = 0.347], MFR was significantly lower in the stress–rest group [3.07 (2.43–3.88) vs. 3.50 (2.63–4.10), P = 0.007]. There was a weak correlation between Δ t stress–rest and rMBF (r = −0.259, P = 0.002) and between Δ t stress–rest and MFR (r = 0.163, P = 0.049), and the proportion of patients with abnormally high rMBF was significantly decreasing with increasing Δ t stress–rest. Conclusion Intravenously applied adenosine induces a long-lasting hyperaemic effect on the myocardium. Consequently, rapid stress–rest protocols could lead to an overestimation of rMBF and an underestimation of MFR. [ABSTRACT FROM AUTHOR]

Background Robust venous outflow (VO) profiles, measured by degree of venous opacification on pre-thrombectomy CT angiography (CTA) studies, are strongly correlated with favorable outcomes in patients with large vessel occlusion acute ischemic stroke treated by thrombectomy. However, VO measurements are laborious and require neuroimaging expertise. Objective To develop a semi-automated method to measure VO using CTA and CT perfusion imaging studies. Methods We developed a graphical interface using The Visualization Toolkit, allowing for voxel selection at the confluence and bilateral internal cerebral veins on CTA along with arterial input functions (AlFs) from both internal carotid arteries. We extracted concentration-time curves from the CT perfusion study at the corresponding locations associated with AIF and venous output function (VOF). Outcome analyses were primarily conducted by the Mann-Whitney U and Jonckheere-Terpstra tests. Results Segmentation at the pre-selected AIF and VOF locations was performed on a sample of 97 patients. 65 patients had favorable VO (VO+) and 32 patients had unfavorable VO (VO-). VO+ patients were found to have a significantly shorter VOF time to peak (8.26; 95% CI 7.07 to 10.34) than VO- patients (9.44; 95% CI 8.61 to 10.91), P=0.007. No significant difference was found in VOF curve width and the difference in time between AIF and VOF peaks. Conclusions Time to peak of VOF at the confluence of sinuses was significantly associated with manually scored venous outflow. Further studies should aim to understand better the association between arterial inflow and venous outflow, and capture quantitative metrics of venous outflow at other locations. [ABSTRACT FROM AUTHOR]

Cerebral hyperperfusion syndrome is a rare complication that can occur following carotid artery revascularization procedures in patients with chronic carotid artery stenosis. Cases of hyperperfusion syndrome resulting solely from intravenous tissue plasminogen activator administration, without a history of revascularization, are extremely rare. Only four of such cases have been reported with imaging evidence. This report presents a case of early neurological deterioration in acute ischemic stroke, identified as a form of hyperperfusion syndrome. Imaging evidence supports this diagnosis, and highlights the occurrence of hyperperfusion syndrome after intravenous tissue plasminogen activator administration.

Intracranial atherosclerotic disease (ICAD) is a common cause of ischaemic stroke and transient ischaemic attack (TIA) with a high recurrence rate. It is often referred to as intracranial atherosclerotic stenosis (ICAS), when the plaque has caused significant narrowing of the vessel lumen. The lesion is usually considered symptomatic ICAD/ICAS (sICAD/sICAS) when it has caused an ischaemic stroke or TIA. The severity of luminal stenosis has long been established as a prognostic factor for stroke relapse in sICAS. Yet, accumulating studies have also reported the important roles of plaque vulnerability, cerebral haemodynamics, collateral circulation, cerebral autoregulation and other factors in altering the stroke risks across patients with sICAS. In this review article, we focus on cerebral haemodynamics in sICAS. We reviewed imaging modalities/methods in assessing cerebral haemodynamics, the haemodynamic metrics provided by these methods and application of these methods in research and clinical practice. More importantly, we reviewed the significance of these haemodynamic features in governing the risk of stroke recurrence in sICAS. We also discussed other clinical implications of these haemodynamic features in sICAS, such as the associations with collateral recruitment and evolution of the lesion under medical treatment, and indications for more individualised blood pressure management for secondary stroke prevention. We then put forward some knowledge gaps and future directions on these topics.

Tissue perfusion can be affected by physiology or disease. With the advent of total-body PET, quantitative measurement of perfusion across the entire body is possible. [11C]-butanol is a perfusion tracer with a superior extraction fraction compared with [15O]-water and [13N]-ammonia. To develop the methodology for total-body perfusion imaging, a pilot study using [11C]-butanol on the uEXPLORER total-body PET/CT scanner was conducted. Methods: Eight participants (6 healthy volunteers and 2 patients with peripheral vascular disease [PVD]) were injected with a bolus of [11C]-butanol and underwent 30-min dynamic acquisitions. Three healthy volunteers underwent repeat studies at rest (baseline) to assess test-retest reproducibility; 1 volunteer underwent paired rest and cold pressor test (CPT) studies. Changes in perfusion were measured in the paired rest-CPT study. For PVD patients, local changes in perfusion were investigated and correlated with patient medical history. Regional and parametric kinetic analysis methods were developed using a 1-tissue compartment model and leading-edge delay correction. Results: Estimated baseline perfusion values ranged from 0.02 to 1.95 mL·min-1·cm-3 across organs. Test-retest analysis showed that repeat baseline perfusion measurements were highly correlated (slope, 0.99; Pearson r = 0.96, P < 0.001). For the CPT subject, the largest regional increases were in skeletal muscle (psoas, 142%) and the myocardium (64%). One of the PVD patients showed increased collateral vessel growth in the calf because of a peripheral stenosis. Comorbidities including myocardial infarction, hypothyroidism, and renal failure were correlated with variations in organ-specific perfusion. Conclusion: This pilot study demonstrates the ability to obtain reproducible measurements of total-body perfusion using [11C]-butanol. The methods are sensitive to local perturbations in flow because of physiologic stressors and disease.

Mouse models of hindlimb ischemia (HLI) are used to study peripheral arterial disease and evaluate novel therapies. Contrast-enhanced ultrasound (CEUS) is a noninvasive perfusion measurement technique that is increasingly being employed in these models. The objective of this study was to evaluate two models of severe HLI by CEUS to characterize perfusion recovery and muscle perfusion patterns. Mice undergoing double femoral artery ligation were measured by CEUS and laser Doppler perfusion imaging (LDPI) at baseline and 1–150 d postsurgery. A second group undergoing femoral artery ligation and excision was measured 1–28 d postsurgery. By LDPI, both surgeries showed robust perfusion recovery by 14 d postsurgery. However, by CEUS only a ∼40% perfusion recovery plateau was reached in either group. These results are consistent with our previous work, employing a less severe single femoral artery ligation, that showed perfusion in the ischemic limb does not return to normal by 150 d postsurgery. Cluster analysis of muscle perfusion patterns indicated 3–5 different patterns at day 1 postsurgery. The double ligation model yielded significantly less variable perfusion patterns, suggesting that it can provide more reproducible results. Contrary to LDPI, perfusion as measured by CEUS never fully recovers after hindlimb surgery, even when followed 28–150 d postsurgery. Individual mice can manifest different patterns of muscle perfusion to the same surgery, but these patterns are conserved within and between different surgical techniques. These results may have significant implications for the evaluation of novel therapeutics to treat PAD in mice. [ABSTRACT FROM AUTHOR]

Summary: Flap necrosis continues to occur in skin free flap autologous breast reconstruction. Therefore, we investigated the benefits of indocyanine green angiography (ICGA) using quantitative parameters for the objective, perioperative evaluation of flap perfusion. In addition, we investigated the feasibility of hyperspectral (HSI) and thermal imaging (TI) for postoperative flap monitoring.A single-center, prospective observational study was performed on 15 patients who underwent deep inferior epigastric perforator (DIEP) flap breast reconstruction (n=21). DIEP-flap perfusion was evaluated using ICGA, HSI, and TI using a standardized imaging protocol. The ICGA perfusion curves and derived parameters, HSI extracted oxyhemoglobin (oxyHb) and deoxyhemoglobin (deoxyHb) values, and flap temperatures from TI were analyzed and correlated to the clinical outcomes.Post-hoc quantitative analysis of intraoperatively collected data of ICGA application accurately distinguished between adequately and insufficiently perfused DIEP flaps. ICG perfusion curves identified the lack of arterial inflow (n=2) and occlusion of the venous outflow (n=1). In addition, a postoperatively detected partial flap epidermolysis could have been predicted based on intraoperative quantitative ICGA data. During postoperative monitoring, HSI was used to identify impaired perfusion areas within the DIEP flap based on deoxyHb levels. The results of this study showed a limited added value of TI.Quantitative, post-hoc analysis of ICGA data produced objective and reproducible parameters that enabled the intraoperative detection of arterial and venous congested DIEP flaps. HSI appeared to be a promising technique for postoperative flap perfusion assessment. A diagnostic accuracy study is needed to investigate ICGA and HSI parameters in real-time and demonstrate their clinical benefit.

Abstract Hypothalamus is a crucial deep brain area that is responsible for the integration and coordination of various brain functions. The altered perfusion of hypothalamus during headache caused by medication-overuse headache (MOH) was previously unknown. In the current study, the altered perfusion of hypothalamic subregions in MOH patients was investigated using state-of-the-art 3D pseudo-continuous arterial spin labeling (PCASL) MR imaging. In this study, 29 normal controls subjects (NCs) and 29 MOH patients underwent 3D PCASL and brain structural MR imaging. The hypothalamus was automatically segmented into 10 subunits and the volume of each subunit was automatically determined using Freesurfer software (v7.4.1). All segmented hypothalamic subunits were converted to individual hypothalamic subunit masks. The cerebral blood flow (CBF) images were coregistered with the raw brain structural images and resliced. The CBF value of each hypothalamic subunit was extracted from the warped CBF images. The volume and CBF value of each hypothalamic subunit were analyzed using the independent sample T test and Mann–Whitney U test, receiver operating characteristic (ROC) curve analysis, and Pearson and Spearman correlation analysis. Hypothalamic subunits with significantly decreased perfusion were located in the left posterior, left tubular superior, right anterior–inferior, right tubular inferior, right tubular superior, right posterior subunit and the entire right hypothalamus [CBF value for MOH vs NC (mL/100 g·min): 48.41 ± 6.75 vs 54.08 ± 11.47, 44.44 ± 4.79 vs 48.11 ± 7.73, 41.49 (32.90, 61.46) vs 49.38 ± 10.47, 46.62 ± 7.04 vs 53.90 ± 11.75, 42.12 ± 5.74 vs 47.02 ± 9.99, 42.79 ± 5.15 vs 47.93 ± 10.48 and 43.58 ± 5.06 vs 48.65 ± 9.33, respectively] in MOH compared to NC (P

Abstract Background Quantitative transport mapping (QTM) of blood velocity, based on the transport equation has been demonstrated higher accuracy and sensitivity of perfusion quantification than the traditional Kety’s method-based cerebral blood flow (CBF). This study aimed to investigate the associations between QTM velocity and cognitive function in Alzheimer’s disease (AD) using multiple post-labeling delay arterial spin labeling (ASL) MRI. Methods A total of 128 subjects (21 normal controls (NC), 80 patients with mild cognitive impairment (MCI), and 27 AD) were recruited prospectively. All participants underwent MRI examination and neuropsychological evaluation. QTM velocity and traditional CBF maps were computed from multiple delay ASL. Regional quantitative perfusion measurements were performed and compared to study group differences. We tested the hypothesis that cognition declines with reduced cerebral blood perfusion with consideration of age and gender effects. Results In cortical gray matter (GM) and the hippocampus, QTM velocity and CBF showed decreased values in the AD group compared to NC and MCI groups; QTM velocity, but not CBF, showed a significant difference between MCI and NC groups. QTM velocity and CBF showed values decreasing with age; QTM velocity, but not CBF, showed a significant gender difference between male and female. QTM velocity and CBF in the hippocampus were positively correlated with cognition, including global cognition, memory, executive function, and language function. Conclusion This study demonstrated an increased sensitivity of QTM velocity as compared with the traditional Kety’s method-based CBF. Specifically, we observed only in QTM velocity, reduced perfusion velocity in GM and the hippocampus in MCI compared with NC. Both QTM velocity and CBF demonstrated a reduction in AD vs. controls. Decreased QTM velocity and CBF in the hippocampus were correlated with poor cognitive measures. These findings suggest QTM velocity as potential biomarker for early AD blood perfusion alterations and it could provide an avenue for early intervention of AD.

Background Purpose Methods Results Conclusions Perfusion magnetic resonance imaging (MRI)s plays a central role in the diagnosis and monitoring of neurovascular or neurooncological disease. However, conventional processing techniques are limited in their ability to capture relevant characteristics of the perfusion dynamics and suffer from a lack of standardization.We propose a physics‐informed deep learning framework which is capable of analyzing dynamic susceptibility contrast perfusion MRI data and recovering the dynamic tissue response with high accuracy.The framework uses physics‐informed neural networks (PINNs) to learn the voxel‐wise TRF, which represents the dynamic response of the local vascular network to the contrast agent bolus. The network output is stabilized by total variation and elastic net regularization. Parameter maps of normalized cerebral blood flow (nCBF) and volume (nCBV) are then calculated from the predicted residue functions. The results are validated using extensive comparisons to values derived by conventional Tikhonov‐regularized singular value decomposition (TiSVD), in silico simulations and an in vivo dataset of perfusion MRI exams of patients with high‐grade gliomas.The simulation results demonstrate that PINN‐derived residue functions show a high concordance with the true functions and that the calculated values of nCBF and nCBV converge towards the true values for higher contrast‐to‐noise ratios. In the in vivo dataset, we find high correlations between conventionally derived and PINN‐predicted perfusion parameters (Pearson's rho for nCBF: 0.84±0.03$0.84 \pm 0.03$ and nCBV: 0.92±0.03$0.92 \pm 0.03$) and very high indices of image similarity (structural similarity index for nCBF: 0.91±0.03$0.91 \pm 0.03$ and for nCBV: 0.98±0.00$0.98 \pm 0.00$).PINNs can be used to analyze perfusion MRI data and stably recover the response functions of the local vasculature with high accuracy. [ABSTRACT FROM AUTHOR]

The objective of this review is to examine the potential benefits and challenges of CT-based lung function imaging in radiotherapy over recent decades. This includes reviewing background information, defining related concepts, classifying and reviewing existing studies, and proposing directions for further investigation. The lung function imaging techniques reviewed herein encompass CT-based methods, specifically utilizing phase-resolved four-dimensional CT (4D-CT) or end-inspiratory and end-expiratory CT scans, to delineate distinct functional regions within the lungs. These methods extract crucial functional parameters, including lung volume and ventilation distribution, pivotal for assessing and characterizing the functional capacity of the lungs. CT-based lung ventilation imaging offers numerous advantages, notably in the realm of thoracic radiotherapy. By utilizing routine CT scans, additional radiation exposure and financial burdens on patients can be avoided. This imaging technique also enables the identification of different functional areas of the lung, which is crucial for minimizing radiation exposure to healthy lung tissue and predicting and detecting lung injury during treatment. In conclusion, CT-based lung function imaging holds significant promise for improving the effectiveness and safety of thoracic radiotherapy. Nevertheless, challenges persist, necessitating further research to address limitations and optimize clinical utilization. Overall, this review highlights the importance of CT-based lung function imaging as a valuable tool in radiotherapy planning and lung injury monitoring. [ABSTRACT FROM AUTHOR]

Traumatic spinal cord injury (tSCI) causes an immediate loss of neurological function, and the prediction of recovery is difficult in the acute phase. In this study, we used contrast-enhanced ultrasound imaging to quantify intraspinal vascular disruption acutely after tSCI. In a rodent thoracic tSCI model, contrast-enhanced ultrasound revealed a perfusion area deficit that was positively correlated with injury severity and negatively correlated with hindlimb locomotor function at 8 weeks after injury. The spinal perfusion index was calculated by normalizing the contrast inflow at the injury center to the contrast inflow in the injury periphery. The spinal perfusion index decreased with increasing injury severity and positively correlated with hindlimb locomotor function at 8 weeks after injury. The feasibility of intraoperative contrast-enhanced ultrasound imaging was further tested in a cohort of 27 patients with acute tSCI of varying severity and including both motor-complete and motor-incomplete tSCIs. Both the perfusion area deficit and spinal perfusion index were different between motor-complete and motor-incomplete patients. Moreover, the perfusion area deficit and spinal perfusion index correlated with the injury severity at intake and exhibited a correlation with extent of functional recovery at 6 months. Our data suggest that intraoperative contrast-enhanced, ultrasound-derived metrics are correlated with injury severity and chronic functional outcome after tSCI. Larger clinical studies are required to better assess the reliability of the proposed contrast-enhanced ultrasound biomarkers and their prognostic capacity. Editor's summary: Traumatic spinal cord injury (tSCI) can lead to long-term challenges in motor and sensory function. The neurological examination conducted upon hospital admission may not always provide information regarding the functional outcome of the patient long term. Here, Khaing et al. used intraoperative contrast-enhanced ultrasound to derive two parameters related to blood flow in the injured spinal cord. The authors found that these metrics, perfusion area deficit and spinal perfusion index, were correlated with injury severity in rodents and in a cohort of humans with tSCI. These measurements were also correlated with functional injury severity scores up to 6 months after injury in patients. This study supports further investigation of ultrasound perfusion metrics as candidate markers to predict functional outcome after tSCI. —Molly Ogle [ABSTRACT FROM AUTHOR]

Objective: To investigate the application value of dual-source CT cerebral perfusion imaging combined with serum ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) and lipoprotein-associated phospholipase A2(Lp-PLA2) in the diagnosis and poor prognosis prediction of patients with acute cerebral infarction (ACI). Methods: 151 ACI patients admitted to Hulunbuir People's Hospital from February 2021 to March 2023 were selected as ACI group and 109 healthy volunteers as control group. According to the National Institutes of Health Stroke Scale (NIHSS), ACI patients were divided into mild group (52 cases), moderate group (53 cases), severe group (46 cases); and according to the Modified Rankin Score Scale (mRS), ACI patients were divided into poor prognosis group (37 cases) and good prognosis group (114 cases). All subjects were underwent dual-source CT cerebral perfusion imaging to obtain relevant parameters of cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and time to peak (TTP), and serum UCH-L1 and Lp-PLA2 levels were detected. The value of dual-source CT cerebral perfusion imaging parameters combine with serum UCH-L1 and Lp-PLA2 in the diagnosis of ACI and predicted the prognosis of ACI patients were analyzed by receiver operating characteristic (ROC) curve. Results: CBF and CBV in ACI group were lower than those in control group(P<0.05), MTT and TTP in ACI group were longer than those in control group (P < 0.05) serum UCH-L1 and Lp-PLA2 levels in ACI group were higher than those in con- trol group (P < 0.05) CBF and CBV in severe group were lower than those in moderate group and mild group(P<0.05), MTT and TTP in severe group were longer than those in moderate group and mild group(P<0.05), and serum UCH-L1 and Lp-PLA2 levels in severe group were higher than those in moderate group and mild group (P < 0.05) CBF and CBV in moderate group were lower than those in mild group (P < 0.05) MTT and TTP in moderate group were longer than those in mild group(P<0.05), and serum UCH-L1 and Lp-PLA2 levels in moderate group were higher than those in mild group (P < 0.05) . CBF and CBV in poor prognosis group were lower than those in good prognosis group (P < 0.05) MTT and TTP in poor prognosis group were longer than those in good prognosis group (P < 0.05) and serum UCH-L1 and Lp-PLA2 levels in poor prognosis group were higher than those in good prognosis group (P < 0.05) ROC curve analysis showed that: the area under the curve of combine dual-source CT cerebral perfusion imaging parameters and serum UCH-L1 and Lp-PLA2 in the diagnosis of ACI and the prediction of poor prognosis of ACI were 0.898 and 0.892, respectively, which were higher than those of single index diagnosis and prediction. Conclusion: In ACI patients, dual-source CT cerebral perfusion imaging parameters CBF and CBV decrease, MTT and TTP prolonged, serum UCH-L1 and Lp-PLA2 levels increase, which are relate to the aggravation of ACI nerve defect and poor prognosis. The combination of dual-source CT cerebral perfusion imaging parameters and serum UCH-L1 and Lp-pLA2 has high value in the diagnosis and prognosis analysis of ACI. [ABSTRACT FROM AUTHOR]

Background: Rosacea has a high incidence, significantly impacts quality of life, and lacks sufficient diagnostic techniques. This study aimed to investigate the feasibility of laser speckle contrast imaging (LSCI) for measuring facial blood perfusion in patients with rosacea and to identify differences in blood flow among various facial regions associated with different rosacea subtypes. Methods: From June to December 2023, 45 patients were recruited, with 9 excluded, leaving 36 subjects: 12 with erythematotelangiectatic rosacea (ETR), 12 with papulopustular rosacea (PPR), and 12 healthy controls. The Think View multispectral imaging analyzer assessed inflammation via gray reading values across the full face and five facial areas: forehead, nose, cheeks, and chin. LSCI measured and analyzed blood perfusion in the same areas. Plasma biomarkers interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-a (TNF-a) were tested in different groups. Results: Both ETR and PPR groups showed increased average blood perfusion and facial inflammation intensity by gray values compared to controls, with statistically significant differences. Average blood perfusion of ETR and PPR groups showed increased values in the forehead, cheeks, and nose, compared to controls, and the values in the cheeks were statistically different between ETR and PPR. The facial inflammation intensity of the ETR group showed increased values in the forehead and cheeks, and the PPR group showed increased gray values in the forehead, cheeks, nose, and chin compared to controls, and the values for the cheeks, nose, and chin were statistically significantly different between ETR and PPR. Plasma biomarkers IL-6, IL-1β, and TNF-α were significantly elevated in both ETR and PPR groups compared to controls. Conclusion: LSCI is a valuable, non-invasive tool for assessing blood flow dynamics in rosacea, providing a data foundation for clinical research. Different rosacea subtypes exhibit distinct lesion distribution and blood flow patterns, and both ETR and PPR could affect all facial areas, particularly the cheeks in ETR and the forehead, nose, and chin in PPR. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to validate hyperintense vessel sign (HVS) on FLAIR imaging or posterior cerebral artery (PCA) laterality on MR angiography beyond 4.5 hours after stroke onset. Materials and methods: Data from acute ischemic stroke patients with internal carotid or middle cerebral artery occlusion who underwent CT perfusion imaging at baseline, follow-up MR perfusion imaging and angiography within 30 hours after stroke, without effective recanalization on follow-up imaging, were analysed retrospectively. Patients were separately classified as high or low HVS (>5 or ≤5 slices of HVS), and PCA laterality positive or negative group. We compared core and penumbra volumes at follow-up imaging and neurological outcomes between high or low HVS group, and between PCA laterality positive or negative group. Results: Of 49 patients analyzed, four patients with artifacts were excluded and 45 were classified into high (n = 23) or low (n = 22) HVS group. High group had a smaller core volume (median 32 ml versus 109 ml, p = 0.004), larger penumbra volume at follow-up (68 ml versus 0 ml, p = 0.001), and better outcomes (modified Rankin Scale at three months, 3 versus 5, p = 0.03). For PCA laterality analysis, 1 patient with previously occluded PCA was excluded and 48 patients were classified as positive (n = 22) or negative (n = 26). Positive group had larger core volume (116 ml versus 37 ml), and no significant differences in penumbral volumes or outcomes. Conclusion: Prominent HVS in later time was associated with small core volume, persistent penumbra volume and favorable outcomes. [ABSTRACT FROM AUTHOR]

Introduction: Adult and pediatric ECMO procedures have been increasingly established as conventional life-saving modalities in critical care services across the world. Since 2017, a multidisciplinary team of program advisors for our perfusion education program have aimed to increase cardiovascular perfusion (CVP) student ECMO exposure and improve clinical decision-making. In this QI intervention, the use of 3D computer-based simulation was assessed in establishing a standardized process to improve the diagnosis and treatment of adult ECMO complications among first year CVP students. Methods: The Califia 3D Patient Simulator was incorporated into the curriculum for first year CVP students (n = 26) along with traditional lecture for the adult ECMO complication laboratory session. Pre-class knowledge assessments using de-identified polling software were compared to post-class assessments following the first assigned learning activity. Assessments from students that received simulation before lecture (SIM, n = 15) were compared to students receiving lecture before simulation (LEC, n = 11). User experience questionnaires (UEQ) consisting of 26 questions for six scales of simulation instruction were administered to measure the comprehensive impression of the student experience. Results: Overall median [IQR] pre- and -post knowledge assessment scores were 74% [11] and 84% [11], respectively (p = 0.01). There were no significant differences in pre-class assessment scores between the SIM and LEC groups (74.0% and 74.0%, respectively, p = 0.959). The LEC group achieved higher median post-assessment scores than the SIM group (84% vs 79%, p = 0.032). Among the 26 UEQ survey scales, 23 were positively evaluated (>0.8), and three were a neutral evaluation (−0.8 to 0.8). Cronbach Alpha-Coefficients of >0.78 were measured for attractiveness, perspicuity, efficacy, and stimulation. The coefficient for dependability was 0.37. 25 (96.2%) students indicated that 3D simulation was beneficial to improving ECMO clinical decision-making. Conclusions: In this QI intervention, the implementation of computer-based 3D simulation following lecture was perceived by learners to help improve the diagnosis and treatment of ECMO-related complications. [ABSTRACT FROM AUTHOR]

Introduction: Cardiovascular Magnetic Resonance (CMR) has become an essential non-invasive imaging modality in the diagnosis and management of various cardiac conditions. Its ability to provide detailed assessments of myocardial perfusion and scar tissue without ionizing radiation offers distinct advantages over other imaging techniques. Aim is to evaluate the role of Cardiovascular Magnetic Resonance (CMR) in assessing myocardial perfusion and scar tissue and to investigate the correlation of CMR findings with clinical parameters and outcomes, including angina symptoms, history of myocardial infarction, and revascularization procedures. Materials and Methods: This prospective observational study was conducted with a sample size of 75 patients who had clinical indications for CMR. The study included adult’s aged 18 years and older, excluding those with contraindications to MRI or severe renal impairment. CMR imaging was performed using a 1.5 Tesla MRI scanner, incorporating cine imaging, stress and rest perfusion imaging, late gadolinium enhancement (LGE), and T1 and T2 mapping. Results: The study found that 30% of participants exhibited myocardial perfusion defects, with a mean scar burden of 15% across the study cohort. Participants with angina symptoms, a history of myocardial infarction, or those who underwent revascularization procedures had higher scar burdens and lower left ventricular ejection fractions (LVEF). Significant correlations were observed between CMR findings and clinical outcomes, with participants who had a history of myocardial infarction showing the highest scar burden (mean 30%) and lowest LVEF (mean 45%). Conclusion: CMR is a valuable tool for evaluating myocardial perfusion and scar tissue, with significant correlations to clinical outcomes. This study confirms the importance of CMR in the management of cardiovascular diseases and suggests that further research and advancements are necessary to enhance its accessibility and utility in diverse healthcare settings. [ABSTRACT FROM AUTHOR]