OBJECTIVE: To measure the relative T1 (rT1) value in different hypo-perfused regions after ischemic stroke using T1 mapping derived by Strategically Acquired Gradient Echo (STAGE) and assess its relationship with onset time and severity of ischemia.
METHODS: Sixty-three patients with acute anterior circulation ischemic stroke from 2017 to 2022 who underwent STAGE, diffusion weighted imaging (DWI) and dynamic susceptibility contrast perfusion weighted imaging (DSC-PWI) within 7 days were retrospectively enrolled. The areas with reduced diffusion and hypo-perfusion were segmented based on apparent diffusion coefficient (ADC) value < 0.62 × 10-3mm2/s and time-to-maximum (Tmax) thresholds (4, 6, 8, and 10 seconds). We measured the T1 value in the diffusion reduced and every 2 s Tmax strata regions and calculated rT1 (T1ipsi/T1contra) to explore the relationship between rT1 value, Tmax, and onset time.
RESULTS: rT1 value was increased in diffusion reduced (1.42) and hypo-perfused regions (1.02, 1.06, 1.12, 1.27, Tmax 4-6 s, 6-8 s, 8-10 s, > 10 s, respectively; all different from 1, P < 0.001). rT1 value was positively correlated with Tmax (rs = 0.61, P < 0.001) and onset time in area with reduced diffusion (rs = 0.39, P = 0.014).
CONCLUSIONS: Increased rT1 value in different hypo-perfused brain regions using T1 mapping derived by STAGE may reflect the edema; it was associated with the severity of Tmax and showed a weak correlation with the onset time in diffusion reduced areas.

BACKGROUND: Aneurysmal subarachnoid hemorrhage (aSAH) is frequently complicated by delayed cerebral ischemia (DCI), leading to poor outcomes. Early diagnosis of DCI is crucial for improving survival and outcomes but remains challenging in comatose patients. In this study, we aimed to evaluate computed tomography with angiography and perfusion (P-CT) as a screening modality on postictal days four and eight for impending DCI after aSAH in comatose patients using vasospasm with hypoperfusion (hVS) as a surrogate and DCI-related infarction as an outcome measure. Two objectives were set: (1) to evaluate the screening\'s ability to accurately risk stratify patients and (2) to assess the validity of P-CT screening.
METHODS: We conducted a retrospective review of the records of comatose patients with aSAH from January 2019 to December 2021 who were monitored with P-CT scans on days four and eight. The event rates of DCI-related infarction, hVS, and endovascular rescue therapy (ERT) were analyzed, and the sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) for DCI were calculated. DCI-related infarction was defined as new secondary cerebral infarction > 48 h < 6 weeks post aSAH not attributable to other causes, and hVS was defined as arterial narrowing with corresponding hypoperfusion on P-CT.
RESULTS: Fifty-six comatose patients were included, and 98 P-CT scans were performed. The incidence of DCI-related infarction was 40%. Screening P-CT on days four and eight found vasospasm in 23% of all patients, including 11% with hVS. A positive hVS on day four or eight revealed a relative risk of 2.4 [95% confidence interval (CI) 1.13-5.11, p = 0.03], sensitivity of 23% (95% CI 8-45, p = 0.03), specificity of 95% (95% CI 36-100, p = 0.03), PPV of 0.83 (95% CI 0.36-1.00, p = 0.03), and NPV of 0.65 (95% CI 0.50-0.78). Six positive P-CT scans led to digital subtraction angiography in five patients, three of whom received ERT. All ERT-intervened patients developed DCI-related infarction.
CONCLUSIONS: P-CT resulted in few interventions and often resulted in late detection of DCI at an irreversible stage. Although a positive P-CT result accurately predicts impending DCI-related infarction, screening on days four and eight alone in comatose patients with aSAH often fails to timely detect impending DCI. Based on our analysis, we cannot recommend P-CT as a screening modality. P-CT is likely best used as a confirmatory test prior to invasive interventions when guided by continuous multimodal monitoring; however, prospective studies with comparison groups are warranted. The need for a reliable continuous screening modality is evident because of the high rate of deterioration and narrow treatment window.

BACKGROUND: As per the latest Surviving Sepsis Campaign guidelines, fluid resuscitation should be guided by repeated measurements of blood lactate levels until normalization. Nevertheless, raised lactate levels should be interpreted in the clinical context, as there may be other causes of elevated lactate levels. Thus, it may not be the best tool for real-time assessment of the effect of hemodynamic resuscitation, and exploring alternative resuscitation targets should be an essential research priority in sepsis.
OBJECTIVE: To compare the 28-d mortality in two clinical patterns of septic shock: hyperlactatemic patients with hypoperfusion context and hyperlactatemic patients without hypoperfusion context.
METHODS: This prospective comparative observational study carried out on 135 adult patients with septic shock that met Sepsis-3 definitions compared patients with hyperlactatemia in a hypoperfusion context (Group 1, n = 95) and patients with hyperlactatemia in a non-hypoperfusion context (Group 2, n = 40). Hypoperfusion context was defined by a central venous saturation less than 70%, central venous-arterial PCO2 gradient [P(cv-a)CO2] ≥ 6 mmHg, and capillary refilling time (CRT) ≥ 4 s. The patients were observed for various macro and micro hemodynamic parameters at regular intervals of 0 h, 3 h, and 6 h. All-cause 28-d mortality and all other secondary objective parameters were observed at specified intervals. Nominal categorical data were compared using the χ2 or Fisher\'s exact test. Non-normally distributed continuous variables were compared using the Mann-Whitney U test. Receiver operating characteristic curve analysis with the Youden index determined the cutoff values of lactate, CRT, and metabolic perfusion parameters to predict the 28-d all-cause mortality. A P value of < 0.05 was considered significant.
RESULTS: Patient demographics, comorbidities, baseline laboratory, vital parameters, source of infection, baseline lactate levels, and lactate clearance at 3 h and 6 h, Sequential Organ Failure scores, need for invasive mechanical ventilation, days on mechanical ventilation, and renal replacement therapy-free days within 28 d, duration of intensive care unit stay, and hospital stay were comparable between the two groups. The stratification of patients into hypoperfusion and non-hypoperfusion context did not result in a significantly different 28-d mortality (24% vs 15%, respectively; P = 0.234). However, the patients within the hypoperfusion context with high P(cv-a)CO2 and CRT (P = 0.022) at baseline had significantly higher mortality than Group 2. The norepinephrine dose was higher in Group 1 but did not achieve statistical significance with a P > 0.05 at all measured intervals. Group 1 had a higher proportion of patients requiring vasopressin and the mean vasopressor-free days out of the total 28 d were lower in patients with hypoperfusion (18.88 ± 9.04 vs 21.08 ± 8.76; P = 0.011). The mean lactate levels and lactate clearance at 3 h and 6 h, CRT, P(cv-a)CO2 at 0 h, 3 h, and 6 h were found to be associated with 28-d mortality in patients with septic shock, with lactate levels at 6 h having the best predictive value (area under the curve lactate at 6 h: 0.845).
CONCLUSIONS: Septic shock patients fulfilling the hypoperfusion and non-hypoperfusion context exhibited similar 28-d all-cause hospital mortality, although patients with hypoperfusion displayed a more severe circulatory dysfunction. Lactate levels at 6 h had a better predictive value in predicting 28-d mortality than other parameters. Persistently high P(cv-a)CO2 (> 6 mmHg) or increased CRT (> 4 s) at 3 h and 6 h during early resuscitation can be a valuable additional aid for prognostication of septic shock patients.

Arterial spin labeling (ASL) is helpful in early diagnosis and differential diagnosis of Alzheimer\'s disease (AD), with advantages including no exposure to radioactivity, no injection of a contrast agent, more accessible, and relatively less expensive.
To establish the perfusion pattern of different dementia in Chinese population and evaluate the effectiveness of ASL in differentiating AD from cognitive unimpaired (CU), mild cognitive impairment (MCI), and frontotemporal dementia (FTD).
Four groups of participants were enrolled, including AD, FTD, MCI, and CU based on clinical diagnosis from PUMCH dementia cohort. ASL image was collected using 3D spiral fast spin echo-based pseudo-continuous ASL pulse sequence with background suppression and a high resolution T1-weighted scan covering the whole brain. Data processing was performed using Dr. Brain Platform to get cerebral blood flow (ml/100g/min) in every region of interest cortices.
Participants included 66 AD, 26 FTD, 21 MCI, and 21 CU. Statistically, widespread hypoperfusion neocortices, most significantly in temporal-parietal-occipital cortices, but not hippocampus and subcortical nucleus were found in AD. Hypoperfusion in parietal lobe was most significantly associated with cognitive decline in AD. Hypoperfusion in parietal lobe was found in MCI and extended to adjacent temporal, occipital and posterior cingulate cortices in AD. Significant reduced perfusion in frontal and temporal cortices, including subcortical nucleus and anterior cingulate cortex were found in FTD. Hypoperfusion regions were relatively symmetrical in AD and left predominant especially in FTD.
Specific patterns of ASL hypoperfusion were helpful in differentiating AD from CU, MCI, and FTD.

OBJECTIVE: In refractory out-of-hospital cardiac arrest (OHCA) with prolonged whole-body ischaemia, global tissue injury proceeds even after establishment of circulation with extracorporeal cardiopulmonary resuscitation (ECPR). We aimed to investigate the role of biomarkers reflecting hypoperfusion, inflammation, and organ injury in prognostication of patients with refractory OHCA managed with ECPR.
RESULTS: This nationwide retrospective study included 226 adults with refractory OHCA managed with ECPR in Denmark (2011-2020). Biomarkers the first days after ECPR-initiation were assessed. Odds ratio of favourable neurological status (Cerebral Performance Category 1-2) at hospital discharge was estimated by logistic regression analyses. Cut-off values were calculated using the Youden\'s index. Fifty-six patients (25%) survived to hospital discharge, 51 (91%) with a favourable neurological status. Factors independently associated with favourable neurological status were low flow time <81 min, admission leukocytes ≥12.8 × 109/L, admission lactate <13.2 mmol/L, alkaline phosphatase (ALP) < 56 (day1) or <55 U/L (day2), and day 1 creatine kinase MB (CK-MB) < 500 ng/mL. Selected biomarkers (leukocytes, C-reactive protein, and lactate) were significantly better predictors of favourable neurological status than classic OHCA-variables (sex, age, low-flow time, witnessed arrest, shockable rhythm) alone (P = 0.001) after hospital admission.
CONCLUSIONS: Biomarkers of hypoperfusion (lactate), inflammation (leucocytes), and organ injury (ALP and CK-MB) were independently associated with neurological status at hospital discharge. Biomarkers of hypoperfusion and inflammation (at hospital admission) and organ injury (days 1 and 2 after ECPR) may aid in the clinical decision of when to prolong or terminate ECPR in cases of refractory OHCA.

Introduction In polytrauma patients, it is crucial to identify the severity of the injuries to ensure patient safety and survival. Polytrauma leads to hypotension and hypoperfusion, which results in an anaerobic metabolism with acidosis and a decrease in base excess. Thus, blood lactate levels above a certain threshold indicate the existence of global tissue hypoxia, which is a precursor to shock and multiple organ dysfunction syndrome (MODS). The serum lactate and base deficit (BD) levels are used in polytrauma patients as measures of damage severity and resuscitation endpoints and as a way to evaluate therapy efficacy and to predict outcomes. Thus, arterial blood gas analysis is of great value in assessing the status and prognosis of patients with polytrauma. There are few comparative studies on the predictive values of these markers in trauma patients. To determine which measure can more accurately predict the prognosis of polytrauma patients, the present study investigated the predictive values of mortality of these indicators for mortality within 48 hours of admission to the emergency room (ER) in patients with polytrauma. Methods This prospective study was designed for a single tertiary care center in northern India. We included 90 patients with polytrauma who were between the ages of 18 and 70 years, with the exception of pregnant women, who presented to the ER within six hours of injury with an injury severity score (ISS) >16, serum lactate level >2.0 mmol/L, and BD -4.0 mEq/L at the time of admission. If the patient\'s ISS was >16 at the time of ER presentation, arterial blood samples were drawn to determine the serum lactate and BD level at the time of admission and at 12, 24, and 48 hours intervals after ER admission. The primary outcome was the change in serum lactate and BD level in polytrauma. The secondary outcomes were an association of serum lactate and BD with mortality and the correlation between serum lactate with the BD and ISS with mortality of polytrauma patients. The timing of all outcome assessments was at 48 hours after each patient\'s ER admission. Results Lactate clearance from 0-12 hours (t = 2.28, p <0.05), 0-24 hours (t = 6.01, p <0.001), and 0-48 hours (t = 7.98, p <0.001) and a correction in BD from 0-24 (t = 2.68, p <0.01 ) and 0-48 hours (t = 5.46, p <0.001) were significantly higher in nonsurvivors as compared with survivors. In survivors and nonsurvivors, mean serum lactate levels (2.46 ± 1.46 versus 4.15 ± 2.99, t = 3.31, p <0.001, 95%Cl) and mean BD (-3.17 ± 2.58 versus -6.5 ± 4.91, t = 3.86, p <0.001, 95%CI) had a statistically significant difference. The serum lactate and BD levels at time of ER admission (r L0, BD0 = -0.765, p <0.01) and 48 hours after ER admission (r L48, BD 48 = -0.652, p <0.001) were highly negatively correlated. Conclusion In polytrauma patients, serum lactate and BD are simple, quick, and independent biochemical predictors of 48-hour mortality, and this single arterial blood test would thereby improve decision-making for resuscitation effectiveness. Prolonged lactate and BD normalization time were associated with higher mortality. Serum lactate and BD are negatively correlated. A higher ISS at admission was associated with a higher incidence of mortality in polytrauma patients.

Background: Transient ischemic attack (TIA) has a high incidence of recurrent vascular events. Hypoperfusion is one of the factors that are closely correlated with 7-day recurrence of TIA. This study aimed to evaluate the power of hypoperfusion shown on magnetic resonance (MR) perfusion imaging in predicting the incidence of 7-day recurrence of ischemic events after TIA. Methods/Design: REATTACK is a prospective multi-centered cohort study on the correlation between MR perfusion and TIA recurrence. Ninety patients aged ≥18 years with recent (<7 days after onset) clinical TIA will be continuously included. All the patients will undergo diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) assessments within 24 h after the onset of TIA. The subjects will then be divided into a PWI positive group and a PWI negative group according to the time-to-maximum of the residue function (T max ). PWI will be repeated after 7 days and in 3 months. The primary clinical outcome will be the recurrence of TIA within 7 days after the onset of TIA. Secondary outcomes will be the recurrence of TIA in 3 months and modified Rankin scale (mRS) score. A chi-square test will be performed to compare the difference in the incidence of recurrent TIA between the two groups, and rank sum test in the mRS score. Multivariate logistic regression will be simultaneously performed to analyze the risk factors for the recurrence of TIA. Discussion: The results of this study will confirm whether abnormal T max helps to identify the patients with TIA who have high risks of recurrent ischemic events. This would largely improve the prognosis of patients with TIA. Trial Registration: www.chictr.org.cn, registration number: ChiCTR2000031863, registered on 12 April 2020.

UNASSIGNED: Certain heart conditions and diseases are common in Down syndrome (DS; trisomy 21), but their role in early onset dementia that is prevalent in older adults with DS has not been evaluated. To address this knowledge gap, we conducted a study of risk factors for low neurocognitive/behavioral scores obtained with a published dementia test battery (DTB). Participants were adults with DS living in New York (N = 29; average age 46 years). We asked three questions. 1. Does having any type of heart disease affect the association between DTB scores and chronological age? 2. Does thyroid status affect the association between heart disease and DTB scores? 3. Are the E4 or E2 alleles of apolipoprotein E (APOE) associated with DTB scores or with heart disease?
UNASSIGNED: The study was retrospective, pilot, and exploratory. It involved analysis of information in a database previously established for the study of aging in DS. Participants had moderate intellectual disability on average. Information for each person included: gender, age, a single DTB score obtained by combining results from individual subscales of the DTB, the presence or absence of heart disease, thyroid status (treated hypothyroidism or normal), and APOE genotype. Trends were visualized by inspection of graphs and contingency tables. Statistical methods used to evaluate associations included Pearson correlation analysis, Fisher\'s exact tests (2-tailed), and odds ratio analysis. P values were interpreted at the 95% confidence level without Bonferroni correction. P values >.05<.1 were considered trends.
UNASSIGNED: The negative correlation between DTB scores and age was significant in those with heart disease but not in those without. Heart disease was significantly associated with DTB scores >1 SD below the sample mean; there was a strong association between heart disease and low DTB scores in those with treated hypothyroidism but not in those with normal thyroid status. The APOE genotype was weakly associated with heart disease (E4, predisposing; E2, protective) in males.
UNASSIGNED: On the basis of the potentially important findings from the present study, large prospective studies are warranted to confirm and extend the observations. In these, particular heart conditions or diseases and other medical comorbidities in individuals should be documented.

Peripheral perfusion index (PPI) is an indicator reflecting perfusion. Patients undergoing long time surgeries are more prone to hypoperfusion and increased lactate. Few studies focusing on investigating the association between PPI and surgical patients\' prognoses. We performed this study to find it out.
From January 2019 to September 2019, we retrospected all surgical patients who were transferred to ICU, Xinyang Central hospital, Henan province, China. Inclusive criteria: age ≥ 18 years old; surgical length ≥ 120 min. Exclusive criteria: died in ICU; discharging against medical advice; existing diseases affecting blood flow of upper limbs, for example, vascular thrombus in arms; severe liver dysfunction. We defined \"prolonged ICU stay\" as patients with their length of ICU stay longer than 48 h. According to the definition, patients were divided into two groups: \"prolonged group\" (PG) and \"non-prolong group\" (nPG). Baseline characteristics, surgical and therapeutic information, ICU LOS, SOFA and APACHE II were collected. Besides we gathered data of following parameters at 3 time points (T0: ICU admission; T1: 6 h after admission; T2: 12 h after admission): mean artery pressure (MAP), lactate, heart rate (HR), PPI and body temperature. Data were compared between the 2 groups. Multivariable binary logistic regression and ROC (receiver operating characteristic) curves were performed to find the association between perfusion indictors and ICU LOS.
Eventually, 168 patients were included, 65 in PG and 103 in nPG. Compared to nPG, patients in PG had higher blood lactate and lower PPI. PPI showed significant difference between two groups earlier than lactate (T0 vs T1). The value of PPI at two time points was lower in PG than nPG(T0: 1.09 ± 0.33 vs 1.41 ± 0.45, p = 0.001; T1: 1.08 ± 0.37 vs 1.49 ± 0.41, p < 0.001). Increased lactateT1(OR 3.216; 95% CI 1.253-8.254, P = 0.015) and decreased PPIT1 (OR 0.070; 95% CI 0.016-0.307, P < 0.001) were independently associated with prolonged ICU stay. The area under ROC of the PPIT1 for predicting ICU stay> 48 h was 0.772, and the cutoff value for PPIT1 was 1.35, with 83.3% sensitivity and 73.8% specificity.
PPI and blood lactate at T1(6 h after ICU admission) are associated with ICU LOS in surgical patient. Compared to lactate, PPI indicates hypoperfusion earlier and more accurate in predicting prolonged ICU stay.

Indirect measurement of the respiratory exchange ratio (RER) has been shown to predict the occurrence of postoperative complications after major open non-cardiac surgery. Our main objective was to demonstrate the ability of the RER, indirectly measured by the anaesthesia respirator, to predict the occurrence of postoperative complications following laparoscopic surgery. We performed an observational, prospective and monocentric study. Haemodynamic and respiratory parameters were collected at several timepoints to calculate the RER by a non-volumetric method: RER = (FetCO2-FiCO2)/(FiO2-FetO2). Fifty patients were prospectively included. Nine patients (18%) had at least one postoperative complication. The mean RER was significantly higher for the subgroup of patients with complications than the subgroup without (1.04 ± 0.27 vs 0.88 ± 0.13, p < 0.05). The RER could predict the occurrence of post-operative complications with an area under the ROC curve of 0.73 (95% CI 0.59-0.85, p = 0.021). The best cut off was 0.98, with a sensitivity of 56% and a specificity of 88%. One hour after insufflation, the FiO2-FetO2 difference was significantly lower and the RER was significantly higher in the complications subgroup than in the subgroup without complications (4.4/- 1.6% vs 5.8/- 1.2%, p = 0.001 and 0.95 [0.85-1.04] vs 0.83 [0.75-0.92], p = 0.04, respectively). The RER measured during laparoscopic surgery can predict the occurrence of postoperative complications.Trial registration The objectives and procedures of the study was registered at Clinicaltrials.gov (NCT03751579); date: November 23, 2018.