Core Volume Research Articles

A clinical and computed tomography-based nomogram to predict the outcome in patients with anterior circulation large vessel occlusion after endovascular mechanical thrombectomy.

To explore the positive predictors of the clinical outcome in acute ischemic stroke (AIS) patients with anterior circulation large vessel occlusion (ACLVO) after endovascular mechanical thrombectomy (EMT) at a 90-day follow-up, and to establish a nomogram model to predict the clinical outcome. AIS patients with ACLVO detected by multimodal Computed Tomography imaging who underwent EMT were collected. Patients were divided into the favorable and the unfavorable groups according to the 90-day modified Rankin Scale (mRS) score. Univariate and multivariate analyses were performed to investigate predictors of the favorable outcome (mRS of 0-2). A nomogram model for predicting the clinical outcome after EMT was drawn, and the receiver operating characteristic (ROC) curve was used to evaluate its predictive value. Totally 105 patients including 65 patients in the favorable group and 40 in the unfavorable group were enrolled. Multivariate logistic regression analysis showed that admission National Institute of Health Stroke scale (NIHSS) score [0.858 (95% CI 0.778-0.947)], ACLVO at M2 [20.023 (95% CI 2.204-181.907)] and infarct core (IC) volume [0.943 (95% CI 0.917-0.969)] was positively correlated with favorable outcome. The accuracy of the nomogram model in predicting the outcome was 0.923 (95% CI 0.870-0.976), with a cutoff value of 119.6 points. The area under the ROC curve was 0.848 (95% CI 0.780-0.917; sensitivity, 79.7%; specificity, 90.0%). A low Admission NIHSS score, ACLVO at M2, and a small IC volume were positive predictors for favorable outcome. The nomogram model may well predict the outcome in AIS patients with ACLVO after EMT.

Multicenter comparison using two AI stroke CT perfusion software packages for determining thrombectomy eligibility

BackgroundStroke AI platforms assess infarcted core and potentially salvageable tissue (penumbra) to identify patients suitable for mechanical thrombectomy. Few studies have compared outputs of these platforms, and none have been multicenter or considered NIHSS or scanner/protocol differences. Our objective was to compare volume estimates and thrombectomy eligibility from two widely used CT perfusion (CTP) packages, Viz.ai and RAPID.AI, in a large multicenter cohort. MethodsWe analyzed CTP data of acute stroke patients with large vessel occlusion (LVO) from four institutions. Core and penumbra volumes were estimated by each software and DEFUSE-3 thrombectomy eligibility assessed. Results between software packages were compared and categorized by NIHSS score, scanner manufacturer/model, and institution. ResultsPrimary analysis of 362 cases found statistically significant differences in both software's volume estimations, with subgroup analysis showing these differences were driven by results from a single scanner model, the Canon Aquilion One. Viz.ai provided larger estimates with mean differences of 8cc and 18cc for core and penumbra, respectively (p<0.001). NIHSS subgroup analysis also showed systematically larger Viz.ai volumes (p<0.001). Despite volume differences, a significant difference in thrombectomy eligibility was not found. Additional subgroup analysis showed significant differences in penumbra volume for the Phillips Ingenuity scanner, and thrombectomy eligibility for the Canon Aquilion One scanner at one center (7 % increased eligibility with Viz.ai, p=0.03). ConclusionsDespite systematic differences in core and penumbra volume estimates between Viz.ai and RAPID.AI, DEFUSE-3 eligibility was not statistically different in primary or NIHSS subgroup analysis. A DEFUSE-3 eligibility difference, however, was seen on one scanner at one institution, suggesting scanner model and local CTP protocols can influence performance and cause discrepancies in thrombectomy eligibility. We thus recommend centers discuss optimal scanning protocols with software vendors and scanner manufacturers to maximize CTP accuracy.

Blood-brain barrier disruption and hemorrhagic transformation in acute stroke before endovascular reperfusion therapy.

Early blood-brain barrier (BBB) disruption in patients with acute ischemic stroke (AIS) can be detected on perfusion computed tomography (PCT) images before undergoing reperfusion therapy. In this study, we aimed to determine whether early disruption of the BBB predicts intracranial hemorrhage transformation (HT) in patients with AIS undergoing endovascular therapy and further identify factors influencing BBB disruption. We retrospectively analyzed general clinical and imaging data derived from 159 consecutive patients with acute anterior circulation stroke who were admitted to the Department of Neurology of the First Hospital of Jilin University, and who underwent endovascular treatment between January 1, 2021, and March 31, 2023. We evaluated the relationship between BBB destruction and intracranial HT before endovascular reperfusion therapy and examined the risk factors for early BBB destruction. A total of 159 patients with assessable BBB leakage were included. The median (interquartile range, IQR) age was 63 (54-70) years, 108 (67.9%) patients were male, and the median baseline National Institutes of Health Stroke Scale (NHISS) score was 12 (10-15). Follow-up non-contrast computed tomography (NCCT) detected HT in 63 patients. After logistic regression modeling adjustment, we found that BBB leakage in the true leakage area was slightly more than 2-fold risk of HT (odds ratio [OR], 2.01; 95% confidence interval [CI] 1.02-3.92). Heart rate was also associated with HT (OR, 1.03, 95% CI, 1.00-1.05). High Blood-brain barrier permeability (BBBP) in the true leakage area was positively correlated with infarct core volume (OR, 1.03; 95% CI, 1.01-1.05). Early BBB destruction before endovascular reperfusion therapy was associated with HT, whereas high BBBP correlated positively with infarct core volume.

Effects of drive pulse shape on graded metal pushered single shell capsule implosions on the National Ignition Facility

Graded metal pushered single shells (PSS) are a viable alternative to low-Z capsules (Z is the atomic number) for indirect drive inertial confinement fusion implosions due to enhanced core tamping and radiation trapping, but they can be compromised by the pusher mixing with the fuel. We compare 2-shock and 3-shock laser pulses for Be/Cr PSS capsules filled with deuterium–tritium gas fuel at 6 mg/cc density. 1D radiation-hydrodynamic simulations predict higher core compression and, hence, ∼2× higher fusion yield for the 3-shock drive than for 2-shock. Nevertheless, we observe similar core ion temperatures and fusion yields for both drives. The implosion burn duration is 25% shorter and the core volume is ∼2.5× smaller for the 3-shock drive than for 2-shock, consistent with a higher compression. 1D LASNEX mix simulations using a buoyancy-drag model matching the measured yields also agree with the observed core sizes and burn durations and suggest ∼40% and ∼70% yield degradations for 2-shock and 3-shock drives due to hydrodynamic instabilities and atomic mix at the pusher–fuel interface. At the same time, 2D HYDRA simulations show that mid-mode (2–250) instability degradations are negligible for the 2-shock implosion (9%) and significant (45%) for 3-shock. Subtracting these from the 1D mix simulations, we infer similar degradations from high-mode instabilities and atomic mix for both drives. Due to its robustness to mid-mode instabilities, future pusher–gas mix studies will use the 2-shock drive.

Linear contraction of sand casting Mg–9Gd–3Y–0.5Zr alloy

The effect of geometric characteristics of castings on the linear contraction of sand casting Mg–9Gd–3Y– 0.5Zr alloy (VW93) was studied. The dimensions of free and restrained structure castings were precisely extracted by a 3D scanner and then used for the calculation of the contraction coefficient. The ratio of sand core volume to enveloping volume of casting (γ), was introduced to quantify the degree of constraint caused by sand cores. According to the statistical distribution of free contraction coefficients and the evolution of restrained contraction coefficients against γ, it is indicated that the free contraction coefficient of VW93 alloy equals 1.96%, and the restrained contraction coefficient declines linearly with the increasing γ, which supplies support on predicting the contraction of VW93 alloy through the geometric characteristic of castings.

Endovascular thrombectomy in wake-up stroke guided by arterial spin-labeling and fluid-attenuated inversion recovery versus diffusion-weighted imaging mismatch on MRI.

This purpose of this study is to investigate the effectiveness and safety of utilizing the arterial spin-labeling (ASL) combined with diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) combined with DWI double mismatch in the endovascular treatment of patients diagnosed with wake-up stroke (WUS). In this single-center trial, patients diagnosed with WUS underwent thrombectomy if acute ischemic lesions were observed on DWI indicating large precerebral circulation occlusion. Patients with no significant parenchymal hypersignal on FLAIR and ASL imaging showing a hypoperfusion tissue to infarct core volume ratio of at least 1.2 were included. The participants were divided into groups receiving endovascular thrombectomy plus medical therapy or medical therapy alone, based on their subjective preference. Functional outcomes were assessed using the ordinal score on the modified Rankin scale (mRs) at 90 days, along with the rate of functional independence. In this study, a total of 77 patients were included, comprising 38 patients in the endovascular therapy group and 39 patients in the medical therapy group. The endovascular therapy group exhibited more favorable changes in the distribution of functional prognosis measured by mRs at 90 days, compared to the medical therapy group (adjusted common odds ratio, 3.25; 95% CI, 1.03 to 10.26; P < 0.01). Additionally, the endovascular therapy group had a higher proportion of patients achieving functional independence (odds ratio, 4.0; 95% CI, 1.36 to 11.81; P < 0.01). Importantly, there were no significant differences observed in the incidence of intracranial hemorrhage or mortality rates between the two groups. Guided by the ASL-DWI and FLAIR-DWI double mismatch, endovascular thrombectomy combined with standard medical treatment appears to yield superior functional outcomes in patients with WUS and large vessel occlusion compared to standard medical treatment alone.

Hyperglycemia Is Associated With Computed Tomography Perfusion Core Volume Underestimation in Patients With Acute Ischemic Stroke With Large-Vessel Occlusion.

CT Perfusion (CTP) predictions of infarct core play an important role in the determination of treatment eligibility in large vessel occlusion (LVO) acute ischemic stroke (AIS). Prior studies have demonstrated that blood glucose can affect cerebral blood flow (CBF). Here we examine the influence of acute and chronic hyperglycemia on CTP estimations of infarct core. From our prospectively collected multi-center observational cohort, we identified patients with LVO AIS who underwent CTP with RAPID (IschemaView, Stanford, CA) post-processing, followed by endovascular therapy with substantial reperfusion (TICI 2b-3) within 90 minutes, and final infarct volume (FIV) determination by MRI 48-72 hours post-treatment. Core volume over- and under-estimations were defined as a difference of at least 20 mL between CTP-RAPID predicted infarct core and DWI FIV. Primary outcome was the association of presentation glucose and HgbA1c with underestimation (UE) of core volume and was measured using multivariable logistic regression adjusted for comorbidities and presentation characteristics. Secondary outcomes included frequency of overestimation (OE) of infarct core. Among 256 patients meeting inclusion criteria, median age was 67 [IQR 57-77], 51.6% were female, and 132 (51.6%) and 93 (36.3%) had elevated presentation glucose and elevated HgbA1c, respectively. Median CTP-predicted core was 6 mL [IQR 0-30], median DWI FIV was 14 mL [IQR 6-43] and median difference was 12 mL [IQR 5-35]. Twenty-eight (10.9%) patients had infarct core OE and 68 (26.6%) had UE. Compared to those with no UE, patients with UE had elevated blood glucose (median 119 [103-155] vs 138 [117-195], p=0.002) and HgbA1c (median 5.80 [5.40-6.40] vs 6.40 [5.50-7.90], p=0.009). In multivariable analysis, UE was independently associated with elevated glucose (aOR 2.10, p=0.038) and HgbA1c (aOR 2.37, p=0.012). OE was associated with lower presentation blood glucose (median 109 [ 99-132] in OE vs 127 [107-172] in no OE, p=0.003) and HgbA1c (5.6 [IQR 5.1 - 6.2] in OE vs 5.90 [5.50-6.70] in no OE, p=0.012). Acute and chronic hyperglycemia were strongly associated with CTP UE in patients with LVO AIS undergoing EVT. Glycemic state should be considered when interpreting CTP findings in patients with LVO AIS.

Endovascular therapy in acute ischaemic stroke with large infarction with matched or mismatched clinical-radiological severities: a post-hoc analysis of the ANGEL-ASPECT trial

Endovascular therapy (EVT) was demonstrated effective in acute large vessel occlusion (LVO) with large infarction. Revealing subgroups of patients who would or would not benefit from EVT will further inform patient selection for EVT. This post-hoc analysis of the ANGEL-ASPECT trial, a randomised controlled trial of 456 adult patients with acute anterior-circulation LVO and large infarction, defined by ASPECTS 3-5 or infarct core volume 70-100mL, enrolled from 46 centres across China, between October 2, 2020 and May 18, 2022. Patients were randomly assigned (1:1) to receiving EVT and medical management or medical management alone. One patient withdrew consent, 455 patients were included in this post-hoc analysis and categorised into 4 subgroups by lower or higher NIHSS (< or ≥16) and smaller or larger infarct core (< or ≥70mL). Those with lower NIHSS & smaller core, and higher NIHSS & larger core were considered clinical-radiological matched subgroups; otherwise clinical-radiological mismatched subgroups. Primary outcome was 90-day modified Rankin Scale (mRS). ANGEL-ASPECT is registered with ClinicalTrials.gov, NCT04551664. Overall, 139 (30.5%) patients had lower NIHSS & smaller core, 106 (23.3%) higher NIHSS & larger core, 130 (28.6%) higher NIHSS & smaller core, and 80 (17.6%) lower NIHSS & larger core. There was significant ordinal shift in the 90-day mRS toward a better outcome with EVT in clinical-radiological matched subgroups: lower NIHSS & smaller core (generalised OR, 1.76; 95% CI, 1.18-2.62; p=0.01) and higher NIHSS & larger core (1.64; 1.06-2.54; 0.01); but not in the two clinical-radiological mismatched subgroups. Our findings suggested that in patients with anterior-circulation LVO and large infarction, EVT was associated with improved 90-day functional outcomes in those with matched clinical and radiological severities, but not in those with mismatched clinical and radiological severities. Simultaneous consideration of stroke severity and infarct core volume may inform patient selection for EVT. Unrestricted grants from industry [Covidien Healthcare International Trading (Shanghai), Johnson & Johnson MedTech, Genesis MedTech (Shanghai), and Shanghai HeartCare Medical Technology].

Application of imaging modalities for endovascular thrombectomy of large core infarcts in clinical practice.

Four randomized controlled trials of large infarct core volume (LICV) included three imaging modalities: non-contrast CT (NCCT)-Alberta Stroke Program Early CT Score (ASPECTS), diffusion-weighted imaging (DWI)-ASPECTS, and NCCT-ASPECTS combined with CTP (CT perfusion). However, there is no clear consensus on the optimal imaging modality for endovascular thrombectomy (EVT) trials of large core infarcts. The variety and complexity of imaging modalities make it difficult to apply them in clinical practice. By familiarizing ourselves with these imaging modalities, we can better apply them in the clinic and correctly screen patients with large core infarcts in the anterior circulation who can benefit from EVT therapy.

Large vessel occlusive stroke with milder baseline severity shows better collaterals and reduced harm from thrombectomy transfer delays.

Patients with large vessel occlusion (LVO) stroke presenting with milder baseline clinical severity are common and require endovascular thrombectomy. However, such patients are difficult to recognize using pre-hospital severity-based triage tools and therefore are likely to require a secondary inter-hospital transfer if transported to a non-thrombectomy center. Given the potential for milder severity to represent better underlying cerebrovascular collateral circulation, it is unknown whether transfer delays are still associated with poorer post-stroke outcomes in this patient group. We primarily aimed to examine whether the harmful effect of inter-hospital transfer delay for thrombectomy was different for LVO patients with mild or severe deficits. Secondarily, we also investigated whether imaging markers of collateral circulation were different between severity groups. Registry data from two large Australian thrombectomy centers were used to identify all directly presenting and secondarily transferred LVO patients undergoing thrombectomy, divided into those with lower (NIHSS < 10) and higher (NIHSS ⩾ 10) baseline deficits. The primary outcome was the functional independence or return to baseline defined as modified Rankin Scale 0-2 or baseline at 90 days. Patients with complete baseline CT-perfusion data were analyzed for imaging markers of collateral circulation by baseline severity group. A total of 1210 LVO patients undergoing thrombectomy were included, of which 273 (22.6%) had lower baseline severity. Despite similar thrombolysis and recanalization rates, transferred patients had lower odds of achieving the primary outcome compared to the primary presentation to a thrombectomy center, where baseline severity was higher (adjusted odds ratio (aOR) 0.759 (95% CI 0.576-0.999)), but not when severity was lower (aOR 1.357 (95% CI 0.764-2.409), p-interaction = 0.122). In the imaging analysis of 436 patients, those with milder severity showed smaller median ischemic core volumes (12.6 (IQR 0.0-17.9) vs 27.5 (IQR 6.5-37.1) mL, p < 0.001)), higher median perfusion mismatch ratio (10.8 (IQR 4.8-54.5) vs 6.6 (IQR 3.5-16.5), p < 0.001), and lower median hypoperfusion intensity ratio (0.25 (IQR 0.18-0.38) vs 0.40 (IQR 0.22-0.57), p < 0.001). Patients receiving secondary inter-hospital transfer for thrombectomy had poorer outcomes compared to those presenting directly to a thrombectomy center if baseline deficits were severe, but this difference was not observed when baseline deficits were milder. This result may potentially be due to our secondary findings of significantly improved collateral circulation markers in lower-severity LVO patients. As such, failure of pre-hospital screening tools to detect lower-severity LVO patients for pre-hospital bypass to a thrombectomy center may not necessarily deleteriously affect outcome. Anonymized data not published within this article will be made available on request from any qualified investigator.

Assessment of Perfusion Volumes by a New Automated Software for Computed Tomography Perfusion

IntroductionTo compare the perfusion volumes assessed by a new automated CT perfusion (CTP) software iStroke with the circular singular value decomposition software RAPID and determine its predictive value for functional...

Tumour Size and Overall Survival in a Cohort of Patients with Unifocal Glioblastoma: A Uni- and Multivariable Prognostic Modelling and Resampling Study.

Published models inconsistently associate glioblastoma size with overall survival (OS). This study aimed to investigate the prognostic effect of tumour size in a large cohort of patients diagnosed with GBM and interrogate how sample size and non-linear transformations may impact on the likelihood of finding a prognostic effect. In total, 279 patients with a IDH-wildtype unifocal WHO grade 4 GBM between 2014 and 2020 from a retrospective cohort were included. Uni-/multivariable association between core volume, whole volume (CV and WV), and diameter with OS was assessed with (1) Cox proportional hazard models +/- log transformation and (2) resampling with 1,000,000 repetitions and varying sample size to identify the percentage of models, which showed a significant effect of tumour size. Models adjusted for operation type and a diameter model adjusted for all clinical variables remained significant (p = 0.03). Multivariable resampling increased the significant effects (p < 0.05) of all size variables as sample size increased. Log transformation also had a large effect on the chances of a prognostic effect of WV. For models adjusted for operation type, 19.5% of WV vs. 26.3% log-WV (n = 50) and 69.9% WV and 89.9% log-WV (n = 279) were significant. In this large well-curated cohort, multivariable modelling and resampling suggest tumour volume is prognostic at larger sample sizes and with log transformation for WV.

Propensity score matched analysis of functional outcome in five thousand cases of robot-assisted radical prostatectomy versus high-intensity focused ultrasound

BackgroundTo evaluate functional outcome after robot-assisted radical prostatectomy (RARP) and high-intensity focused ultrasound (HIFU) ablation for prostate cancer. MethodsWe retrospectively reviewed 4,983 RARP and 230 HIFU procedures performed at a single tertiary center. A 1:4 ratio propensity score matching (PSM) was performed to achieve baseline equivalence in age, body mass index (BMI), comorbidities, clinical stage, prostate specific antigen (PSA), prostate volume, biopsy grade, and number of positive cores. Functional outcomes based on International Prostate Symptom Score (IPSS), International Index of Erectile Function (IIEF-5) scores, and incontinence rates were evaluated at 6, 12, and 24 months. Resultstotal of 193 HIFU cases matched to 760 cases of RARP, were included. No differences were observed in perioperative IPSS at all follow-up periods. Despite comparative erectile function at baseline, HIFU showed significantly better erectile function preservation compared to RARP, with mean IIEF-5 scores of 9.5 versus 4.8, 9.5 versus 5.8, and 8.4 versus 6.7 at 6, 12, and 24 months, respectively (all P < 0.001). Pad-free rates at 6 and 12 months were comparable, with over 96% achieving continence at 12 months in both groups, although the rate of ≤1 pad/day at last follow-up was slightly better in HIFU (98.9% vs. 96.7%, P = 0.049). Subgroup analysis on partial (PGA) and whole gland ablation (WGA) showed no differences in IIEF-5 and incontinence but increased voiding difficulty in WGA versus PGA after 12 months of therapy (P < 0.05). Preoperative IIEF-5 ≥17 and HIFU were significant predictors of early erectile function recovery at 6 months (HR 4.4 and 5.0; all P < 0.001). No differences were observed in treatment-free survival between PGA, WGA, and RARP. ConclusionHIFU shows better performance in early recovery and preservation of erectile function after treatment for prostate cancer without increasing the risk of treatment failure. Patients with moderate to severe erectile dysfunction (IIEF-5 <17) prior to surgery should be warned of poor recovery after treatment.

Investigating geometry adjustments for enhanced performance in a PeLUIt-10 MWt pebble bed HTGR with OTTO refueling scheme

This research investigates the impact of changes in reactor geometry to discover more optimal dimensional options for nuclear power plants with potential applications in remote areas of Indonesia. The reactor used is PeLUIt-10, a pebble bed High-Temperature Gas-cooled Reactor (HTGR) with a 10 MWt capacity and a “once-through-then-out” or OTTO fuel loading scheme. The neutronic and thermal–hydraulic performances of PeLUIt-10 were analyzed with its core size altered, first by modifying its height-to-diameter ratio (H/D ratio) and second by reducing its core volume. These analyses were performed using the Pebble Bed Reactor Neutron Diffusion (PEBBED) Code, a specialized tool to analyze HTGR reactor physics parameters, particularly Pebble Bed Reactors.. Neutronic parameters analyzed include total fuel flow, burnup, power peaking factor, and power density distribution. For thermal-hydraulics and safety, parameters include steady-state and transient fuel temperatures, especially in Depressurized Loss of Forced Cooling (DLOFC) accidents. Results show that the optimal design, maintaining a volume of 5 m3, is a reactor with a height of 159.57 cm and a diameter of 200 cm (H/D ratio of 0.8). The fuel can achieve a maximum burnup of 80.97 MWD/kg-HM at this size. Power density distribution at these dimension is better than another dimensions, with a relatively low power peaking value of 1.4. For safety parameters, the fuel temperature in transient conditions remains below the safety limit. Meanwhile, when the core volume is reduced, the minimum burnup target of 60 MWD/kg-HM at a reactor volume of 4.4 m3 with a diameter of 172 cm and height of 189.2 cm. Thus, for OTTO-cycle PeLUIt-10, altering H/D ratio is more beneficial.

Fibrosis modeling choice affects morphology of ventricular arrhythmia in non-ischemic cardiomyopathy.

Introduction: Patients with non-ischemic cardiomyopathy (NICM) are at risk for ventricular arrhythmias, but diagnosis and treatment planning remain a serious clinical challenge. Although computational modeling has provided valuable insight into arrhythmic mechanisms, the optimal method for simulating reentry in NICM patients with structural disease is unknown. Methods: Here, we compare the effects of fibrotic representation on both reentry initiation and reentry morphology in patient-specific cardiac models. We investigate models with heterogeneous networks of non-conducting structures (cleft models) and models where fibrosis is represented as a dense core with a surrounding border zone (non-cleft models). Using segmented cardiac magnetic resonance with late gadolinium enhancement (LGE) of five NICM patients, we created 185 3D ventricular electrophysiological models with different fibrotic representations (clefts, reduced conductivity and ionic remodeling). Results: Reentry was induced by electrical pacing in 647 out of 3,145 simulations. Both cleft and non-cleft models can give rise to double-loop reentries meandering through fibrotic regions (Type 1-reentry). When accounting for fibrotic volume, the initiation sites of these reentries are associated with high local fibrotic density (mean LGE in cleft models: p 0.001, core volume in non-cleft models: p = 0.018, negative binomial regression). In non-cleft models, Type 1-reentries required slow conduction in core tissue (non-cleftsc models) as opposed to total conduction block. Incorporating ionic remodeling in fibrotic regions can give rise to single- or double-loop rotors close to healthy-fibrotic interfaces (Type 2-reentry). Increasing the cleft density or core-to-border zone ratio in cleft and non-cleftc models, respectively, leads to increased inducibility and a change in reentry morphology from Type 2 to Type 1. Conclusions: By demonstrating how fibrotic representation affects reentry morphology and location, our findings can aid model selection for simulating arrhythmogenesis in NICM.

Impact of temporal resolution on perfusion metrics, therapy decision, and radiation dose reduction in brain CT perfusion in patients with suspected stroke

PurposeCT perfusion of the brain is a powerful tool in stroke imaging, though the radiation dose is rather high. Several strategies for dose reduction have been proposed, including increasing the intervals between the dynamic scans. We determined the impact of temporal resolution on perfusion metrics, therapy decision, and radiation dose reduction in brain CT perfusion from a large dataset of patients with suspected stroke.MethodsWe retrospectively included 3555 perfusion scans from our clinical routine dataset. All cases were processed using the perfusion software VEOcore with a standard sampling of 1.5 s, as well as simulated reduced temporal resolution of 3.0, 4.5, and 6.0 s by leaving out respective time points. The resulting perfusion maps and calculated volumes of infarct core and mismatch were compared quantitatively. Finally, hypothetical decisions for mechanical thrombectomy following the DEFUSE-3 criteria were compared.ResultsThe agreement between calculated volumes for core (ICC = 0.99, 0.99, and 0.98) and hypoperfusion (ICC = 0.99, 0.99, and 0.97) was excellent for all temporal sampling schemes. Of the 1226 cases with vascular occlusion, 14 (1%) for 3.0 s sampling, 23 (2%) for 4.5 s sampling, and 63 (5%) for 6.0 s sampling would have been treated differently if the DEFUSE-3 criteria had been applied. Reduction of temporal resolution to 3.0 s, 4.5 s, and 6.0 s reduced the radiation dose by a factor of 2, 3, or 4.ConclusionReducing the temporal sampling of brain perfusion CT has only a minor impact on image quality and treatment decision, but significantly reduces the radiation dose to that of standard non-contrast CT.

CTP-Defined Large Core Is a Better Predictor of Poor Outcome for Endovascular Treatment Than ASPECTS-Defined Large Core.

Recent trials confirmed the effectiveness of endovascular therapy in patients with large ischemic cores. Yet the optimal neuroimaging modalities to define large core remains unclear. We tried to address this question by comparing the functional outcomes in patients receiving thrombectomy selected by either noncontrast computed tomography Alberta Stroke Program Early Computed Tomography Score (ASPECTS) or computed tomography perfusion (CTP). This study retrospectively selected patients enrolled in the International Stroke Perfusion Registry between August 2011 and April 2022. Patients with acute stroke with large vessel occlusion in anterior circulation treated with endovascular therapy were included. All received both CTP and noncontrast computed tomography. The primary outcome was defined as poor functional outcome represented by a modified Rankin Scale score of 5 to 6 at 3 months. Large cores were defined in terms of either (1) noncontrast computed tomography ASPECTS ≤5 or (2) core volume ≥70 mL on CTP. A total of 1115 patients were included in the analysis, of which 90 patients had ASPECTS ≤5 (8.1%) and 97 patients CTP core ≥70 mL (8.7%). A fair agreement between ASPECTS and CTP with a κ value of 0.31 (0.21-0.40) was found. Compared with patients with neither CTP nor ASPECTS large cores, those with only ASPECTS-defined large cores (ie, ASPECTS ≤5; n=56) did not have a higher adjusted odds of poor outcome (29%; odds ratio, 1.84 [0.91-3.73]; P=0.089). However, patients with CTP large core but not ASPECTS-defined large core (n=63) had a higher adjusted odds of poor outcome (60%; odds ratio, 3.91 [2.01-7.60]; P<0.001). In time-stratified subgroup analysis (>6 versus ≤6 hours), ASPECTS showed no discriminative difference between ≤5 and >5 in poor outcome for patients receiving endovascular therapy within 6 hours. CTP core ≥70 mL-defined large cores are more predictive of poor outcome than ASPECTS ≤5-defined core in endovascular therapy patients, particularly within 6 hours after stroke onset.

Clinical relevance of intracranial hemorrhage after thrombectomy versus medical management for large core infarct: a secondary analysis of the SELECT2 randomized trial

BackgroundThe incidence of intracerebral hemorrhage (ICH) and its effect on the outcomes after endovascular thrombectomy (EVT) for patients with large core infarcts have not been well-characterized.MethodsSELECT2 trial follow-up imaging was...

Effects of low-tube voltage coronary CT angiography on plaque and pericoronary fat assessment: intraindividual comparison.

To investigate the effects of low tube voltage on coronary plaques and pericoronary fat assessment, and to compare their extent among various levels of low voltage. Patients were recommended for high-pitch low-tube voltage coronary computed tomography angiography (CCTA), and they were included if they had poor image quality and were referred to a conventional CCTA. The patients were classified into a low-voltage group (with 70-kV, 80-kV, and 90-kV subgroups) and a conventional group (100/120 kV). Their total plaque and subcomponent volumes and pericoronary fat attenuation index (FAI) were measured. A total of 1002 image slices (from 65 patients and 74 plaques) were included, including 21, 31, 13, 4, and 61 patients in the 70-kV, 80-kV, 90-kV, 100-kV, and 120-kV groups respectively. The CT values of noncalcified plaques in the conventional and low-voltage groups were 54.6 ± 21.3 HU and 31.5 ± 22.6 HU, respectively (p < 0.05). Compared with the conventional group, the necrotic core and calcification volume were increased, and the fibrolipid volume, periplaque, and right coronary artery FAI were decreased in the low-voltage group and its subgroups (p < 0.001). The magnitude of changes in fibrous and calcification volumes increased in the 70-kV subgroup compared with that in the 90-kV subgroup (p < 0.05). Low tube voltages, particularly of 70 kV, have a significant effect on coronary plaque and FAI. The effect of low voltage on plaque composition is characterized by a polarization pattern, i.e., a decrease in fibrolipid (medium density) and an increase in necrotic core (low density) and calcification (high density). Our results highlight the comparability and repeatability of plaque and pericoronary fat assessments facilitated by the same or a similar tube voltage. It is necessary to carry out studies on the specificity threshold of low tube voltage at each level. • Low tube voltage had a significant effect on coronary plaque and pericoronary fat, particularly 70 kV. • The effect of low tube voltage on plaque composition shows the shift from medium-density mixed components to low- and high-density components. • It is necessary to correct the specificity threshold or attenuation difference for low tube voltage at each level.

Prediction and effectiveness study of fracture distribution based on an artificial neural network technology and production performance data detection method: a case study of Ordovician carbonate formation in the Tahe oilfield, Tarim Basin

To solve the difficulty of predicting the spatial distribution of fracture linear density and clarify the controlling influence of tectonic factors on the effectiveness of fractures. This article combines core, conventional logging, imaging logging, and 3D seismic volume data and uses artificial intelligence neural network technology combined with the sequential Gaussian method to establish a linear density volume prediction model for fractures in the study area. In addition, production dynamic data are applied to verify the effectiveness of the fractures. The results show that the artificial intelligence neural network technique is highly applicable with an accuracy of up to 76.8% in predicting the fracture linear density. The fracture linear density is controlled by tectonic activity, and the fracture linear density increases sharply in the areas adjacent to the main faults, the fracture superposition site, and the intersection site of multiple faults, with the fracture linear density reaching 8.65 fractures per meter in study areas. The effective distance of fracture connectivity is mostly concentrated between 550 and 670 m. When the difference in fracture density along the structural ridge is between 2 and 4 fractures/meter, the effectiveness of the fractures is strong.