Perfusion Abnormalities Research Articles

Quantitative MRI detects delayed perfusion and impact of bronchial artery dilatation on pulmonary circulation in patients with cystic fibrosis.

MRI detects abnormal lung perfusion in patients with cystic fibrosis (CF). However, little is known about the contribution of bronchial arteries to lung perfusion in CF. We hypothesized that delayed perfusion can be detected by dynamic contrast-enhanced (DCE-)MRI and thatbronchial artery dilatation (BAD) is associated with changes in lung perfusion. Morpho-functional MRI was prospectively acquired in 75 patients with CF (18.7 ± 7.6 years, range 6-39 years). Lungs and perfusion defects were segmented automatically to quantify perfusion defects in percent (QDP). Pulmonary blood flow (PBF), mean transit time (MTT), and perfusion delay were calculated for the whole lung, inside normally perfused and perfusion defect areas. Chest MRI score and BAD were assessed visually. QDP and PBF correlated with MRI global score (r = 0.58 and -0.53, p < 0.001). In normally perfused lung, PBF was higher (161.2 ± 77.9 mL/100 mL/min vs. 57.5 ± 26.4 mL/100 mL/min, p < 0.001), and MTT (5.4 ± 1.7 s vs. 6.9 ± 2.3 s, p < 0.001) and perfusion delay were shorter than in perfusion defect areas (4.6 ± 5.3 s vs.13.4 ± 16.2 s, p < 0.001). 48 (64.0%) patients showed BAD, had higher QDP (44.6 ± 20.8% vs. 17.3 ± 11.0%, p < 0.001) and lower PBF (91.9 ± 54.8 mL/100 mL/min vs. 178.3 ± 77.4 mL/100 mL/min, p < 0.001) than patients without BAD. MTT was shorter (6.3 ± 1.9 s vs. 8.0 ± 2.6 s, p < 0.001), and perfusion delay was longer (13.8 ± 10.1 s vs. 12.8 ± 23.7 s, p < 0.02) inside perfusion defects of patients with BAD compared to without BAD. Perfusion parameters correlate with lung disease severity, and perfusion defects showed delayed perfusion in patients with CF. BAD was associated with more extensive perfusion defects and reduced PBF. Question Dilated bronchial arteries are a common comorbidity in cystic fibrosis (CF), which can cause hemoptysis, but their quantitative contribution to lung perfusion is little researched. Findings Perfusion defects in percent (QDP) enabled objective assessment of perfusion abnormalities in CF patients, while perfusion delay and arterial correlation showed bronchial artery perfusion contribution. Clinical relevance The usage of quantitative perfusion metrics in CF may help tracking disease progression. By also including the proposed metrics perfusion delay and arterial correlation, bronchial artery inflow could be assessed and used to detect early onset of bronchial artery dilation.

Left ventricular diastolic inflow and myocardial flow reserve in patients with coronary artery disease: simultaneous analysis of 4D-Flow and myocardial perfusion using hybrid PETMR.

This study aimed to simultaneously evaluate the association between diastolic left ventricular (LV) inflow and myocardial flow reserve (MFR) using a hybrid PET/MR system in patients with coronary artery disease (CAD). Sixty-seven patients (mean 66 ± 15 years, male 55) with CAD who underwent rest-pharmacological stress 13N-ammonia PET/MR were included. MFR, perfusion defect, and peak filling rate (PFR) were obtained through rest-stress PET. MR acquisition was performed simultaneously during the PET scan to obtain rest-stress 4D flow. Diastolic LV inflow volume (LVinf)(mL/s), peak velocity (peakV)(cm/s), and the change from the rest scan (Δvalue) were computed. Diastolic LV inflow parameters were compared based on the presence or absence of preserved MFR and perfusion defects. In all patients, diastolic LV inflow parameters significantly increased in the stress scan compared to the rest (53.7 ± 23.1 vs. 64.1 ± 32.9ml/s, p = 0.0002; 68.1 ± 15.1 vs. 76.4 ± 20.6cm/s, p = 0.0001 for LVinf and peakV, respectively). PeakV and PFR showed a significant correlation for rest and stress (r = 0.4, p = 0.01; r = 0.3, p = 0.03 for rest and stress, respectively).ΔpeakV significantly correlated to stress MBF, and MFR (r = 0.3, p = 0.007; r = 0.3, p = 0.04 for stress MBF, and MFR, respectively). Among patients with preserved LVEF (n = 47), when were divided into 4 subgroups based on the median myocardial flow reserve (MFR, 1.86) and the presence of perfusion defect, ΔpeakV was significantly higher in those with MFR above median and without abnormal perfusion compared to the other groups (21.8 ± 13.6 vs. 13.5 ± 17.0, 13.0 ± 13.5, and 4.6 ± 19.1; p = 0.04, 0.04, and 0.04 for MFR ≥ 1.86 or < 1.86 with or without abnormal perfusion, respectively). Non-invasive assessment of diastolic intra-LV hemodynamics derived from 4D flow MR demonstrated a significant association with coronary vasodilation.

Development of ICP-OES Method for Determination Copper Tetramibi Tetrafluoroborate Active Substance Content in a Kit for Radiopharmaceutical Preparation.

The aim of this study was to develop a fast, quantitative method for the determination of copper tetramibi tetrafluoroborate active substance content in the POLATOM’s PoltechMIBI kit before radiolabeling, using inductively coupled plasma optical emission spectrometry (ICP-OES). Copper tetramibi is a key complex that after radiolabeling with sodium pertechnetate [99mTc], forms technetium [99mTc] sestamibi used primarily for detection of myocardial perfusion abnormalities. Indirect method that determines Cu content was developed and validated according to ICH guidelines and European Pharmacopoeia validation requirements, showing good linearity, accuracy, precision and intermediate precision between two different ICP-OES systems, making it suitable and adequate for routine analysis.

Brain Perfusion Abnormalities using pCASL Imaging in Participants with Acute Post-Traumatic Headache due to Mild Traumatic Brain Injury (P4-12.005)

Brain Perfusion Abnormalities using pCASL Imaging in Participants with Acute Post-Traumatic Headache due to Mild Traumatic Brain Injury (P4-12.005)

567 Creatine Phosphokinase: A Novel Biomarker for Frostbite Severity

Abstract Introduction Serum creatine phosphokinase (CPK) levels in injuries involving muscular damage, such as trauma, are used as an indicator of severity of injury. The role of CPK in frostbite injuries is unknown. We hypothesize that there is an association between serum CPK levels and the severity of frostbite injury. Methods This is a single center retrospective chart review of patients admitted to an ABA verified burn center with an ICD-10 diagnosis of frostbite from October 2022 to July 2024. Patients were excluded from the study if they were under the age of 18, had end stage renal disease or dialysis requirements prior to admission, or no recorded CPK during evaluation. Peak CPK levels were compared to commonly known indicators of frostbite severity and interventions, such as Hennepin scores at presentation and on discharge, tissue plasminogen activator (tPA) administration, need for surgery and abnormal technetium-99 bone scan results. Data on the incidence of acute kidney injury (AKI) using the Kidney Disease Improving Global Outcomes guidelines was also collected. Statistical analysis was computed using Wilcoxon-rank sum and least squares linear regression for continuous variable comparison with statistical significance considered at p&amp;lt; 0.05. Results A total of 95 patient charts were reviewed with 55 patients having recorded a serum CPK during their evaluation for frostbite. Median (interquartile range) of following variables: age 42 years (33.5, 58), initial Hennepin scores 20 (10,30), discharge Hennepin scores 5.5 (1.5, 17), initial CPK 556 U/L (181, 5542), peak CPK 630 (187, 6711), and serum creatinine 0.82 mg/dL (0.68, 1.21). Male sex, bone scan completion, and receipt of tPA were 84%, 84%, and 60%, respectively. Both initial (R=0.51, CI= [0.264, 0.684], p&amp;lt; 0.05) and discharge (R=0.31, CI= [0.037, 0.548], p&amp;lt; 0.05) Hennepin scores demonstrated a weak positive correlation with elevated peak serum CPK levels. Peak serum CPK levels were greater in those who received tPA (2369 [IQR 248-7200] vs. 317 [IQR 112-2063], p&amp;lt; 0.05), but not in those with abnormal perfusion by bone scan (p=0.5) or those that required surgery (2368 [187, 16429] vs 548 [185, 3804], p=0.21). Significantly higher CPK levels were present in those that developed AKI (3511 [IQR 509-14316] vs. 248 [IQR 141-3187], p&amp;lt; 0.05). There was no significant difference in age, unhoused status, alcohol or methamphetamine use between those who were treated with tPA or for those who developed AKI. Conclusions Our results show that CPK levels are weakly correlated with Hennepin scores. Additionally, tPA administration and the development of AKI were associated with elevated CPK levels. Applicability of Research to Practice Clinicians should consider checking CPK levels at the time of presentation as part of their overall work-up for frostbite. More research in the diagnostic efficacy of CPK values in frostbite patients is warranted for treatment algorithms. Funding for the Study N/A

The correlation analysis between Normalized Wall Index and cerebral perfusion in patients with Mild Carotid Artery Stenosis under 3.0T MRI

BackgroundTo explore the relationship between Normalized Wall Index (NWI) and Magnetic Resonance Perfusion Imaging Parameters in Patients with Mild Carotid Artery Stenosis.MethodsInitially, an analysis was conducted on 40 patients from our institution, and we identified through ultrasonographic examinations conducted between July 2021 and August 2022. These patients exhibited carotid artery plaques with mild luminal narrowing (with stenosis rates ranging from 20 to 50%, following the criteria of the North American Symptomatic Carotid Endarterectomy Trial, NASCET). All cases underwent high-resolution magnetic resonance imaging (MRI) of the carotid arteries and cerebral perfusion assessments using 3.0T MRI during the specified timeframe. Based on whether the cerebral hemisphere in the carotid artery supply region had experienced ischemic events, including Transient Ischemic Attacks (TIAs), patients were categorized into symptomatic and asymptomatic groups. Subsequently, the Normalized Wall Index (NWI) of the carotid arteries and the area of abnormal perfusion on the same side of the brain were calculated for each group.ResultsIn the symptomatic group, all patients exhibited perfusion abnormalities in the internal carotid artery supply region, whereas only some patients in the asymptomatic group showed such abnormalities. The NWI of plaques in the symptomatic group was significantly higher than that in the asymptomatic group (P < 0.05).ConclusionThe range of prolongation in mean transit time (MTT) and time to peak (TTP) in patients with perfusion abnormalities was positively correlated with NWI and stenosis rates. The association with NWI was more pronounced and statistically significant (P < 0.05).

Alterations in Liver Perfusion in Adults With Fontan Circulation as Assessed by Dual Cholate Clearance.

Fontan circulation (FC) in complex congenital heart disease is characterized by altered hemodynamics and associated with Fontan-associated liver disease. Patients with FC may exhibit abnormalities in cholate clearance due to abnormal perfusion. We aimed to compare cholate clearance in adults with FC to healthy controls and explore associations between cholate clearance and clinical features. This is a prospective cohort study of patients with FC ≥18 years of age between 2019 and 2022. Systemic and portal hepatic clearance of cholate was assessed using a dual cholate clearance assay (HepQuant Shunt), measuring systemic and portal hepatic filtration rates (HFRs). Systemic HFR/portal HFR ratio (SHUNT%) was calculated. Participants with FC and healthy controls were compared using the Fisher exact test and Wilcoxon test. Univariable regression and multivariable analyses determined associations with clinical variables. There were 35 participants with FC (54% women; median age 29.0 years [interquartile range, 24.0-36.0], 91% White) and 26 controls. In addition to lower platelet counts and higher aspartate aminotransferase to platelet ratio index, and Fibrosis-4 indices, FC participants had lower systemic HFR and portal HFR. SHUNT% was comparable with controls but ranged from 8% to 76%, with 8 (23%) having SHUNT% >30%. In those with FC, increase in SHUNT% was associated with elevated Fontan pressure, higher aortopulmonary collateral flow, decreased oxygen saturation, elevated NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels, thrombocytopenia, and Fibrosis-4 ≥1.45. Cholate clearance, as defined by systemic and portal HFR, is impaired in those with FC. Features of worse Fontan physiology correlate with higher SHUNT%, supporting the hypothesis that hemodynamic derangements play a role in progression of Fontan-associated liver disease. URL: https://www.clinicaltrials.gov; Unique identifier: NCT03726229.

The established chest MRI score for cystic fibrosis can be applied to contrast agent-free matrix pencil decomposition functional MRI: a multireader analysis.

Established morpho-functional chest magnetic resonance imaging (MRI) detects abnormalities in lung morphology and perfusion in people with cystic fibrosis (pwCF) using a dedicated scoring system. Functional assessment is performed using contrast-enhanced (CE) perfusion MRI. Novel matrix pencil decomposition MRI (MP-MRI) is a contrast agent-free alternative, but further validation of this technique is needed. The aim of this study was to evaluate the applicability of the validated morpho-functional chest MRI score for CE perfusion and MP perfusion MRI in a multireader approach. Twenty-seven pwCF (mean age 20.8 years, range 8.4-45.7 years) underwent morpho-functional MRI including CE perfusion and MP perfusion MRI in the same examination. Nine blinded chest radiologists of different experience levels assessed lung perfusion and applied the validated chest MRI score to CE- and MP-MRI. Inter-reader agreement of perfusion scores in CE- and MP-MRI were compared with each other and with the MRI morphology score. Differences according to the readers' experience were also analyzed. The CE perfusion scores were overall lower than the MP perfusion scores (6.2 ± 3.3 vs. 6.9 ± 2.0; p < 0.05) with a strong correlation between both perfusion scores (r = 0.74; p < 0.01). The intraclass correlation coefficient (ICC) as measure for inter-reader agreement was good and significant for both perfusion scores, but higher for the CE perfusion score (0.75, p < 0.001) than for MP perfusion scores (0.61, p < 0.001). The Bland-Altman analysis revealed a difference in CE and MP perfusion scores with more extreme values in CE perfusion scores compared to MP perfusion scores (r = 0.62, p < 0.001). The morphology score showed a moderate to good correlation with the CE perfusion score (r = 0.73, p < 0.01) and the MP perfusion score (r = 0.55, p < 0.01). We did not find a difference in scoring according to the radiological experience level. The established chest MRI score can be applied both to validated CE and novel MP perfusion MRI with a good interreader reliability. The remaining difference between CE and MP-MRI scores may be explained by a lack of routine in visual analysis of MP-MRI and may favor an automated analysis for use of MP-MRI as a noninvasive outcome measure.

Feasibility and Safety of Regadenoson Stress Perfusion Protocol in Pediatric Transplant Patients under General Anesthesia.

Feasibility and Safety of Regadenoson Stress Perfusion Protocol in Pediatric Transplant Patients under General Anesthesia.

SPECT Perfusion Defects and Impaired Strain in Mild COVID-19: A Multimodal Imaging Study with a Female-Predominant Cohort

Background/Objectives: This study investigates the association between mild first-wave COVID-19 infection and subclinical abnormalities in echocardiographic strain parameters and myocardial perfusion using single-photon emission computed tomography (SPECT). Methods: We conducted a retrospective analysis of patients from June 2020 to March 2021 with a history of mild first-wave COVID-19 infection, presenting with nonspecific cardiac symptoms and referred for SPECT myocardial perfusion stress testing. Patients had no obstructive coronary artery disease (CAD) on follow-up invasive angiography or cardiac computed tomography angiography (CCTA) and had transthoracic echocardiographic images of sufficient quality for strain analysis using AutoSTRAIN (TOMTEC®). Results: Fifteen patients met the inclusion criteria. SPECT and echocardiography were reviewed for perfusion and strain defects, respectively, in the inferior, anterior, lateral, and septal myocardial segments. All patients had at least one perfusion abnormality on SPECT: 2/15 (13%) had a fixed defect in one segment, 3/15 (20%) in two, 3/15 (20%) in three, and 7/15 (47%) in four. While 13/15 (87%) patients had normal qualitative findings on traditional echocardiography, 12/15 (80%) had abnormal global longitudinal strain (GLS) (&gt;−18%) and transregional wall strain abnormality in at least one segment. Abnormalities on SPECT and strain echocardiography demonstrated a moderate but significant 60% concordance, with an intraclass correlation coefficient (ICC) of 0.486 (p = 0.028). Conclusions: Patients with ‘mild’ COVID-19 infection demonstrated a high frequency of abnormalities on SPECT myocardial perfusion imaging (even in the absence of obstructive CAD) which appeared to be concordant with abnormal strain parameters on echocardiography, suggesting possible subclinical effects on myocardial tissue.

Correlation between abnormal microvascular perfusion and quantitative flow ratio after primary PCI in patients with STEMI.

Correlation between abnormal microvascular perfusion and quantitative flow ratio after primary PCI in patients with STEMI.

Role of early MRI in predicting the risk of hippocampal sclerosis in children with febrile status epilepticus.

Epilepsy is the main complication of febrile status epilepticus (FSE) in children. The association between FSE and the development of hippocampal sclerosis (HS) and mesial temporal lobe epilepsy (MTLE) is controversial. This study primarily aimed to evaluate the role of magnetic resonance imaging (MRI) in diffusion-weighted imaging (DWI) sequence during the acute phase of FSE in predicting long-term development of HS and epilepsy. The secondary objective was to assess the value of arterial spin labeling (ASL) perfusion MRI in the acute phase of FSE. Patients with a first episode of FSE between 6 months and 5 years of age who underwent early MRI were retrospectively included. MRI analysis focused on the DWI signal and the presence of perfusion abnormalities on ASL imaging. We also examined the first electroencephalogram (EEG) during the acute phase. Long-term follow-up analysis assessed the occurrence of HS on MRI scans and the development of epilepsy. A total of 15 children were included. The presence of restricted diffusion areas on MRIs performed in the acute phase after FSE was significantly associated with the later development of HS. However, the association between restricted diffusion areas on early MRIs and the development of pharmaco-resistant epilepsy on follow-up, found in 3 patients, was not statistically significant. There was a trend for an association between early ASL perfusion MRI changes and EEG findings when both examinations were performed closely. Early DWI-MRI seems to play a major role in the prognostic evaluation of FSE in children. It may help to determine hippocampal involvement and assess the risk of subsequent HS. However, the study data are insufficient to conclude on the association between diffusion abnormalities and the development of MTLE. Although ASL perfusion may provide additional insight, more data are needed.

Percutaneous closure of anomalous left coronary artery from pulmonary artery rare procedure in desperate situation: case report.

When anomalous left coronary artery from the pulmonary artery is diagnosed in infancy, it is associated with high mortality, but collaterals permit rare adult survival despite coronary steal. We report normalisation of perfusion abnormality after transcatheter proximal left coronary occlusion in a symptomatic adult with inducible ischaemia. A forty-eight-year-old female presented with exertional chest pain; EKG showed sinus rhythm with left axis deviation with intraventricular conduction defect. Echocardiogram diagnosed an anomalous left coronary artery arising from the pulmonary artery with normal ventricular function which was further confirmed by CT. The case was discussed with the surgical team, and it was decided to surgically ligate. The patient did not give consent for the surgical procedure; the patient was taken up for the procedure. Device was released safely after confirming the position on echocardiogram after the procedure showed improvement in intraventricular conduction defect and QTc duration, and also no significant ischaemic changes were noted. Myocardial perfusion scintigraphy was done after 6 months of procedure which showed improvement in contractile function and perfusion of left ventricle. Device closure in long-standing anomalous left coronary artery from pulmonary artery case is safe, and long-term follow-up is needed.

Computed Tomography Cerebral Perfusion to Predict Functional Outcome in Pediatric Head Injury: A Comparative Study of Voxel-Based and Whole-Brain Perfusion.

Computed Tomography Cerebral Perfusion to Predict Functional Outcome in Pediatric Head Injury: A Comparative Study of Voxel-Based and Whole-Brain Perfusion.

Effectiveness of CT perfusion in posterior circulation stroke: evaluation of perfusion abnormalities and associated clinical signs

PurposeAcute posterior circulation stroke (PCS) is characterized by often non-specific clinical signs, with neuroimaging playing a pivotal role in assessment in the emergency setting. The aim of this study was to investigate the effectiveness of CT Perfusion (CTP) maps in detecting acute PCS and to identify clinical factors associated with perfusion abnormalities.MethodsWe retrospectively analyzed clinical and radiological data of consecutive patients with acute PCS admitted to our Stroke Unit that underwent CTP. Follow-up NECT or MRI was performed to confirm the diagnosis of PCS. The effectiveness of CTP to identify PCS was evaluated as the ratio of the CTP in which perfusion abnormalities, compatible with an ischemic event, were present in at least one CTP map among MTT, CBF, TTP, and CBV. Multivariate logistic regression analysis was conducted to identify clinical factors associated with perfusion abnormalities.ResultsCTP showed alterations in 69 of 107 PCS (64.5%) included in final analysis and MTT proved to be the most sensitive. Multivariate analysis showed that atrial fibrillation (OR = 8.571, CI 95% 2.224–33.037, p = 0.002), dyslipidemia (OR = 0.285, CI 95% 0.100–0.814, p = 0.019), visual field deficits (OR = 3.372, CI 95% 1.020–11.150, p = 0.046), and higher neurological deficit (NIHSS > 5) (OR = 4.054, CI 95% 1.147–14.331, p = 0.030) were significantly associated with perfusion abnormalities on CTP.ConclusionCT perfusion can be a valuable resource for detecting acute PCS showing a moderately high positivity rate, higher than that of NECT alone or CTA. These findings contribute to the growing body of evidence supporting the use of perfusion imaging in acute posterior circulation stroke.

SPECT/CT Scan Images to Evaluate COVID-19 Pulmonary Complications: A Systematic Review.

The highly contagious 2019 novel coronavirus that causes coronavirus disease 2019 increased the scientific community's interest in diagnosing and monitoring COVID-19. Due to the findings about the association between COVID-19 infection and pulmonary disturbances, the need for the use of complementary tests that can be carried out, preserving the health of patients, has grown. In this context, single-photon emission computed tomography (SPECT) was performed during the COVID-19 pandemic to assess and try to diagnose lung lesions. The aim of this current review was to investigate the types of SPECT images most commonly used and the main pulmonary parenchymal lesions and different lung perfusion abnormalities observed in these images in individuals with COVID-19 in different countries in the world. Electronic searches in the MEDLINE/PubMed, Embase, Scopus, Web of Science, and CINAHL databases were conducted in December 2022. Studies that used SPECT/CT scans to evaluate pulmonary involvements due to COVID-19, with no language restriction, were included. Two reviewers, who independently examined titles and abstracts, identified records through the database search and reference screening, and irrelevant studies were excluded based on the eligibility criteria. Relevant complete texts were analyzed for eligibility, and all relevant studies were included in a systematic review. Eight studies with regular methodological quality were included. The types of SPECT examinations used in the included articles were SPECT/CT, Q SPECT/CT, and V/Q SPECT. The possible pulmonary complication most observed was pulmonary embolism. This systematic review demonstrated that SPECT/CT scans, mainly with perfusion methods, allow the maximum extraction of benefits from pulmonary images, in safety, suggesting efficiency in the differential diagnosis, including of respiratory diseases of different etiology, and with diagnostics and additional analyses, can possibly aid the development of suitable therapeutic strategies for each patient. Randomized clinical trials and studies of good methodological quality are necessary to confirm the findings of this review and help better understand the types of SPECT images most commonly used and the main pulmonary parenchymal lesions observed in the images in individuals with COVID-19.

Atrial Fibrillation as an Independent Predictor of Myocardial Ischemia.

Background and Objectives: Atrial fibrillation (AF) and coronary artery disease (CAD) are highly prevalent cardiovascular conditions. This study investigated the role of AF in myocardial ischemia, as assessed with myocardial perfusion imaging (MPI), in patients with suspected stable CAD. Materials and Methods: Our retrospective study included 259 individuals with a negative medical history of CAD who underwent 99mTc tetrofosmin MPI-single-photon emission computed tomography (SPECT)-for nonspecific symptoms to rule out stable CAD. Results: Of the enrolled patients, 90 MPIs were from patients with AF and 169 MPIs were from patients without AF. Semi-quantitative assessments of the extent and severity of perfusion abnormalities according to the summed stress score (SSS) and summed difference score (SDS) were conducted. It was found that patients with a history of AF, compared to patients without AF, were older (p < 0.001), of the male gender (p < 0.001), and had dyslipidemia (p = 0.019). History of AF was associated with increased SSS ≥ 4 (OR 5.12, p < 0.001) and SDS ≥ 2 (OR 2.66, p < 0.001). After adjustment for other risk factors, AF remained an independent predictor of myocardial ischemia on MPI-SPECT. Conclusions: In the current study, an association of AF with extensive perfusion defects in MPI-SPECT studies was found in patients with clinically suspected CAD independently of common cardiovascular risk factors.

Tranexamic acid impact on platelet adhesion to the endothelium after shock conditions: A protective effect?

Trauma and hemorrhagic shock lead to microcirculatory disturbances related to endothelial injury and endothelial glycocalyx (EG) degradation. Improved outcomes following trauma and hemorrhagic shock have been linked to protection of the EG layer, which is a topic of increasing investigation. Early tranexamic acid (TXA) administration following trauma and hemorrhagic shock improves outcomes in clinic studies. Recent translational studies have also shown that early TXA administration protects the EG following shock insults; the impact on blood-endothelial cell interactions is unknown. Platelet adherence to vascular endothelium may contribute to microcirculatory disturbances; the effects of TXA on this phenomenon are uncertain. Microfluidic devices have been used to study the behavior of endothelial cells and platelets under flow conditions. We hypothesize that the protective effect of TXA against EG degradation would prevent shock-induced platelet adhesion to the microvasculature. This was studied in a microfluidic cell culture model under a controlled microenvironment. Microfluidic endothelial cell cultures were exposed to flow conditions under control or hypoxia-epinephrine exposure. Tranexamic acid was added to the perfusate at various times in control and experimental groups. Endothelial glycocalyx thickness, degradation products, and platelet adhesion to the endothelium were measured. Tranexamic acid protected the glycocalyx from degradation following hypoxia-reoxygenation-epinephrine exposure. Platelet adhesion to the endothelium was significantly reduced by TXA in a time sensitive manner. Tranexamic acid may protect the microvasculature from perfusion abnormalities following shock conditions. This is likely due to inhibition of platelet adhesion and mitigating thromboinflammation at the endothelium in the microvasculature.

High-Fidelity MRI Assessment of Cerebral Perfusion in Healthy Neonates Less Than 1 Week of Age.

Perfusion imaging of the brain has important clinical applications in detecting neurological abnormalities in neonates. However, such tools have not been available to date. Although arterial-spin-labeling (ASL) MRI is a powerful noninvasive tool to measure perfusion, its application in neonates has encountered obstacles related to low signal-to-noise ratio (SNR), large-vessel contaminations, and lack of technical development studies. To systematically develop and optimize ASL perfusion MRI in healthy neonates under 1 week of age. Prospective. Thirty-two healthy term neonates (19 female; postnatal age 1.9 ± 0.7 days). 3.0 T; T2-weighted half-Fourier single-shot turbo-spin-echo (HASTE) imaging, single-delay and multi-delay 3D gradient-and-spin-echo (GRASE) large-vessel-suppression pseudo-continuous ASL (LVS-pCASL). Three studies were conducted. First, an LVS-pCASL MRI sequence was developed to suppress large-vessel spurious signals in neonatal pCASL. Second, multiple post-labeling delays (PLDs) LVS-pCASL were employed to simultaneously estimate normative cerebral blood flow (CBF) and arterial transit time (ATT) in neonates. Third, an enhanced background-suppression (BS) scheme was developed to increase the SNR of neonatal pCASL. Repeated measure analysis-of-variance, paired t-test, spatial intraclass-correlation-coefficient (ICC), and voxel-wise coefficient-of-variation (CoV). P-value <0.05 was considered significant. LVS-pCASL reduced spurious ASL signals, making the CBF images more homogenous and significantly reducing the temporal variation of CBF measurements by 58.0% when compared to the standard pCASL. Multi-PLD ASL yielded ATT and CBF maps showing a longer ATT and lower CBF in the white matter relative to the gray matter. The highest CBF was observed in basal ganglia and thalamus (10.4 ± 1.9 mL/100 g/min). Enhanced BS resulted in significantly higher test-retest reproducibility (ICC = 0.90 ± 0.04, CoV = 8.4 ± 1.2%) when compared to regular BS (ICC = 0.59 ± 0.12, CoV = 23.6 ± 3.8%). We devised an ASL method that can generate whole-brain CBF images in 4 minutes with a test-retest image ICC of 0.9. This technique holds potential for studying neonatal brain diseases involving perfusion abnormalities. MR imaging of cerebral blood flow in neonates remains a challenge due to low blood flow rates and confounding factors from large blood vessels. This study systematically developed an advanced MRI technique to enhance the reliability of perfusion measurements in neonates. The proposed method reduced signal artifacts from large blood vessels and improved the signal-to-noise ratio of brain perfusion images. With this approach, whole-brain neonatal perfusion can be measured in 4 minutes with excellent reproducibility. This technique may provide a useful tool for studying neonatal brain maturation and detecting perfusion abnormalities in diseases. 2 TECHNICAL EFFICACY: Stage 1.

Intraoperative Renal Near-Infrared Spectroscopy Monitoring as a Predictor of Renal Outcomes in Cardiac Surgery.

BACKGROUND Acute renal failure (ARF) is a critical complication following open-heart surgery, significantly impacting morbidity and mortality. This study aimed to evaluate the association between intraoperative renal near-infrared spectroscopy (NIRS) findings and postoperative ARF in 357 patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). MATERIAL AND METHODS This prospective study included 357 patients undergoing open-heart surgery with CPB. ARF diagnosis was based on KDIGO criteria. NIRS sensors were placed bilaterally at the T12/L2 level under ultrasound guidance, and renal oxygenation (rSO2) values were continuously monitored intraoperatively. Patients were categorized into ARF and non-ARF groups for comparative analysis. RESULTS ARF developed in 12.3% (n=44) of patients. ARF patients were older (p=0.024) and had longer surgery (p<0.001), CPB (p=0.004), and aortic cross-clamping durations (p=0.013). They required more blood products (p<0.001) and intra-aortic balloon pump support (p=0.027). Intensive care unit stays were significantly longer in ARF patients (p=0.036). NIRS analysis showed significant rSO2 reductions in ARF patients. Time spent with rSO2 below 80%, 70%, and 60% was a strong predictor of ARF. Receiver operating characteristic (ROC) analyses demonstrated that time exceeding 30 minutes below the 60% threshold predicted ARF with 96.5% specificity and 86.4% sensitivity. CONCLUSIONS Intraoperative NIRS monitoring is crucial for detecting renal perfusion abnormalities during high-risk surgeries. Declines below 80%, 70%, and 60% thresholds strongly predict ARF. Timely interventions, such as fluid resuscitation and hemodynamic support, can mitigate risks. ARF patients require intensive postoperative monitoring due to prolonged ICU stays and complications.