DWI Volume Research Articles

Abstract TP141: Understanding Potential Limitations of CTP Imaging in Early Window Large Vessel Anterior Circulation Strokes

Background: Computerized tomography perfusion (CTP) imaging serves as a valuable modality for the assessment of individuals with a large vessel anterior circulation stroke. Current literature proposes that employing CTP imaging in patients within the initial time frame of less than 8 hours, may lead to an overestimation of the projected infarct core, specifically when utilizing cerebral blood flow (CBF) less than 30%. The hypoperfusion intensity ratio (HIR) may result in overestimation. We sought to further investigate the interplay of CTP parameters in patients presenting within 8 hours of symptom onset of stroke, to assess the accuracy of core infarct estimation. Methods: A retrospective cohort study analyzing patients with large vessel anterior occlusion (LVAO) who underwent CTP and mechanical thrombectomy within 24 hours of symptom onset between January 2017 to December 2022. RAPID software estimates the infarct core using CBF <30%. DWI-MRI determined final infarct volume. A multivariate logistic regression model was employed to assess the impact of HIR and reperfusion success on outcomes. Results: Ninety-seven patients were identified within an 8-hour time window. CBF<30% overestimated core infarct volume (mL) in 22 patients (22.6%) with a mean of 15.72 (range 4.4-37.7) and a median of 22.85. Of these, 2 patients experienced poor reperfusion (9%) while 20 had successful reperfusion (91%). Of the patients who did have successful reperfusion, an average of 13.57mL core was overpredicted compared to the DWI volumes. A multivariate logistic regression model adjusting for degree of reperfusion, administration of thrombolytic, and time from symptom onset showed that HIR strongly predicted the probability of core estimation with an odds ratio of 148.6, 95% CI [21.0-1048.8], (p<0.001). Conclusion: HIR exceeding 0.4 demonstrates a predictive capacity for core overestimation in early-window LVAO patients. Our study affirms this observation with statistical significance. The integration of HIR as a parameter for early-window LVAO core computation shows promise, and has potential ramifications for patient selection for thrombectomy. In this context, utilization of further databases is imperative for validation and broader application of HIR.

Random expert sampling for deep learning segmentation of acute ischemic stroke on non-contrast CT.

Outlining acutely infarcted tissue on non-contrast CT is a challenging task for which human inter-reader agreement is limited. We explored two different methods for training a supervised deep learning algorithm: one that used a segmentation defined by majority vote among experts and another that trained randomly on separate individual expert segmentations. The data set consisted of 260 non-contrast CT studies in 233 patients with acute ischemic stroke recruited from the multicenter DEFUSE 3 (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3) trial. Additional external validation was performed using 33 patients with matched stroke onset times from the University Hospital Lausanne. A benchmark U-Net was trained on the reference annotations of three experienced neuroradiologists to segment ischemic brain tissue using majority vote and random expert sampling training schemes. The median of volume, overlap, and distance segmentation metrics were determined for agreement in lesion segmentations between (1) three experts, (2) the majority model and each expert, and (3) the random model and each expert. The two sided Wilcoxon signed rank test was used to compare performances (1) to 2) and (1) to (3). We further compared volumes with the 24 hour follow-up diffusion weighted imaging (DWI, final infarct core) and correlations with clinical outcome (modified Rankin Scale (mRS) at 90 days) with the Spearman method. The random model outperformed the inter-expert agreement ((1) to (2)) and the majority model ((1) to (3)) (dice 0.51±0.04 vs 0.36±0.05 (P<0.0001) vs 0.45±0.05 (P<0.0001)). The random model predicted volume correlated with clinical outcome (0.19, P<0.05), whereas the median expert volume and majority model volume did not. There was no significant difference when comparing the volume correlations between random model, median expert volume, and majority model to 24 hour follow-up DWI volume (P>0.05, n=51). The random model for ischemic injury delineation on non-contrast CT surpassed the inter-expert agreement ((1) to (2)) and the performance of the majority model ((1) to (3)). We showed that the random model volumetric measures of the model were consistent with 24 hour follow-up DWI.

Abstract WMP64: Late Lesion Growth Following Endovascular Therapy: Is 24 Hours Too Early to Assess Acute Infarct Size Including the Effects of Secondary Injury?

Background: Measurement of “final” lesion volume at 24hr following endovascular therapy (post-EVT) has been used in multiple studies as a surrogate for clinical outcome. However, despite successful recanalization, a significant proportion of patients do not experience favorable clinical outcome. Methods: This is a prospective study of acute ischemic stroke patients at two stroke centers who met the following criteria: i) anterior large vessel occlusion (LVO) acute ischemic stroke, ii) attempted EVT, iii) written informed consent obtained, and iv) had MRI post-EVT at 24hr and 5-day. We defined “Early” and “Late” lesion growth as ≥10mL lesion growth between baseline and 24hr DWI, and between 24hr DWI and 5-day FLAIR, respectively. Results: One hundred fourteen patients met study criteria with median age 67 years, 56% female, median admit NIHSS 19, 54% received IV or IA thrombolysis, 67% with M1 occlusion, and median baseline DWI volume 28.2mL. Successful recanalization was achieved in 86% and 67% had complete reperfusion, with an overall favorable clinical outcome rate of 54%. Nearly two thirds (65%) of the patients did not have Late lesion growth with a median volume change of -0.2mL between 24hr and 5-days and an associated high rate of favorable clinical outcome (65%). However, ~1/3 of patients (35%) did have significant Late lesion growth despite successful recanalization (85% TICI 2b/3). Late lesion growth patients had a 26.2mL change in Late lesion volume and 19.9mL change in Early lesion volume. These patients had an increased hemorrhagic transformation rate of 68% with only 1 in 3 patients having favorable clinical outcome. Late lesion growth was independently associated with incomplete reperfusion, hemorrhagic transformation, and unfavorable outcome even after adjusting for admit NIHSS and Early lesion growth. Conclusions: Approximately 1 out of 3 patients had Late lesion growth following EVT, with a favorable clinical outcome occurring in only 1 out of 3 of these patients. Identification of patients with Late lesion growth could be critical to guide clinical management and inform prognosis post-EVT. Additionally it can serve as an imaging biomarker for the development of adjunctive therapies to mitigate reperfusion injury.

Diffusion-Weighted Imaging Lesion Reversal in Older Patients With Stroke Treated With Mechanical Thrombectomy.

Diffusion-weighted imaging lesion reversal (DWIR) is frequently observed after mechanical thrombectomy for acute ischemic stroke, but little is known about age-related differences and impact on outcome. We aimed to compare, in patients <80 versus ≥80 years old, (1) the effect of successful recanalization on DWIR and (2) the impact of DWIR on functional outcome. We retrospectively analyzed data of patients treated for an anterior circulation acute ischemic stroke with large vessel occlusion in 2 French hospitals, who underwent baseline and 24-hour follow-up magnetic resonance imaging, with baseline DWI lesion volume ≥10 cc. The percentage of DWIR (DWIR%), was calculated as follows: DWIR%=(DWIR volume/baseline DWI volume)×100. Data on demographics, medical history, and baseline clinical and radiological characteristics were collected. Among 433 included patients (median age, 68 years), median DWIR% after mechanical thrombectomy was 22% (6-35) in patients ≥80, and 19% (interquartile range, 10-34) in patients <80 (P=0.948). In multivariable analyses, successful recanalization after mechanical thrombectomy was associated with higher median DWIR% in both ≥80 (P=0.004) and <80 (P=0.002) patients. In subgroup analyses performed on a minority of subjects, collateral vessels status score (n=87) and white matter hyperintensity volume (n=131) were not associated with DWIR% (P>0.2). In multivariable analyses, DWIR% was associated with increased rates of favorable 3-month outcomes in both ≥80 (P=0.003) and <80 (P=0.013) patients; the effect of DWIR% on outcome was not influenced by the age group (P interaction=0.185) Conclusions: DWIR might be an important and nonage-dependent effect of arterial recanalization, as it seems to beneficially impact 3-month outcomes of both younger and older subjects treated with mechanical thrombectomy for acute ischemic stroke and large vessel occlusion.

Post-ischemic hyperemia following endovascular therapy for acute stroke is associated with lesion growth

A substantial proportion of acute stroke patients fail to recover following successful endovascular therapy (EVT) and injury to the brain and vasculature secondary to reperfusion may be a contributor. Acute stroke patients were included with: i) large vessel occlusion of the anterior circulation, ii) successful recanalization, and iii) evaluable MRI early after EVT. Presence of hyperemia on MRI perfusion was assessed by consensus using a modified ASPECTS. Three different approaches were used to quantify relative cerebral blood flow (rCBF). Sixty-seven patients with median age of 66 [59–76], 57% female, met inclusion criteria. Hyperemia was present in 35/67 (52%) patients early post-EVT, in 32/65 (49%) patients at 24 hours, and in 19/48 (40%) patients at 5 days. There were no differences in incomplete reperfusion, HT, PH-2, HARM, severe HARM or symptomatic ICH rates between those with and without early post-EVT hyperemia. A strong association (R2 = 0.81, p < 0.001) was found between early post-EVT hyperemia (p = 0.027) and DWI volume at 24 hours after adjusting for DWI volume at 2 hours (p < 0.001) and incomplete reperfusion at 24 hours (p = 0.001). Early hyperemia is a potential marker for cerebrovascular injury and may help select patients for adjunctive therapy to prevent edema, reperfusion injury, and lesion growth.

Abstract TMP61: Lesion Growth Continues Beyond 24 Hours Following Endovascular Therapy In Some Patients With Successful Recanalization

Introduction: Lesion volume on MRI or CT provides evidence of tissue response to successful recanalization by endovascular therapy. The most appropriate time to estimate “infarct” volume remains unclear. Largely for convenience, 24-48 hours has been used in clinical trials and registry datasets which may be too early to determine the final infarct volume. The objective of this study was to quantify the comparability of lesion volume using MRI measured at 24 hours versus 5 days in acute stroke patients following successful recanalization. Methods: Patients were included if they consented to the prospective GUARDS study between April 2018 through February 2022, had LVO of the anterior circulation, were treated with EVT, achieved complete revascularization defined as TICI 2b/3, and imaged with MRI at 2 hours, 24 hours, and 5 days post EVT. Two independent readers measured lesion volumes using a semi-automated validated approach on DWI at 2 and 24 hours, and FLAIR at 5 days. Statistical comparisons of lesion volumes across time points were performed. Lesion growth was defined as change in lesion volume and percent change compared to lesion volume at 2 hours. Results: Sixty-nine patients met all study criteria and were included. Median age was 66 years, 55% female, median admit NIHSS of 18, 62% with M1 LVO, and 46% treated with IV thrombolysis. Post-EVT median lesion volumes were 24mL, 35mL, and 45mL respectively for 2-hour DWI, 24-hour DWI, and 5-day FLAIR. Lesion growth based on median percent change from the 2-hour DWI was 39% [21-96] and 52% [12-145] at 24 hours and 5 days. The difference in lesion growth based on percent change from 24 hours to 5 days was not significant (p=0.17). However, there was a significant difference based on change in lesion volume, 12mL [2-25] at 24 hours and 16mL at 5 days (p=0.029). Fifty-one (74%) patients had DWI volumes at 24 hours that were ≥80% of their FLAIR volumes at 5 days. However, 18 (26%) patients continued to have lesion growth beyond 24 hours, median lesion growth of 18mL,with 11 (61%) of those having lesion growth &gt;20mL. Conclusions: Lesion growth &gt;20mL continues in some patients beyond 24 hours, suggesting that infarct volume at 5 days should be used as the imaging outcome when assessing tissue response to recanalization.

Abstract WMP54: Hyperemia Following Endovascular Therapy For Acute Stroke Is Associated With Ischemic Lesion Growth

Introduction: A substantial proportion of acute stroke patients experience poor outcomes following successful endovascular therapy (EVT) and reperfusion injury to the brain and vasculature may be a contributor. The purpose of this pilot study was to characterize hyperemia following recanalization and test the association of hyperemia with evolution of the ischemic lesion. Methods: Acute stroke patients were included with: i) large vessel occlusion of the anterior circulation, ii) successful recanalization, and iii) evaluable MRI early after EVT. Presence of hyperemia on MRI perfusion was assessed by consensus using a modified ASPECTS. Three different approaches were used to quantify relative cerebral blood flow (rCBF) on early post-EVT, 24 hours, and 5 days. Two independent trained readers measured lesion volumes using a semi-automated validated approach. Results: Sixty-seven patients with median age of 66 [59-76], 57% female, met inclusion criteria. Hyperemia was present in 35/67 (52%) patients early post-EVT (Figure), in 32/65 (49%) patients at 24 hours, and in 19/48 (40%) patients at 5 days. In comparison to control regions, rCBF was elevated by greater than 50% in hyperemic regions. Patients with hyperemia had larger ischemic lesion volumes and early lesion growth. A strong association (R2=0.81, p&lt;0.001) was found between early post-EVT hyperemia (p=0.027) and lesion growth based on DWI volume at 24 hours, after adjusting for DWI volume at 2 hours (p&lt;0.001) and incomplete reperfusion at 24 hours (p=0.001). Conclusions: Hyperemia is frequently observed after successful EVT and is associated with lesion growth at 24 hours. Evidence of hyperemia may identify patients that may benefit from adjunctive therapy to prevent reperfusion injury, edema, and lesion growth.

The regional relationship between CSF VEGF and white matter microstructural integrity in older adults: A voxelwise DTI study

AbstractBackgroundBoth white matter (WM) micro‐ and macro‐ structural abnormalities occur in Alzheimer’s disease (AD) with micro‐structural abnormalities likely preceding macrostructural changes in the AD cascade. Diffusion tensor imaging (DTI) fractional anisotropy (FA) ‐ which is sensitive to factors such as myelination, fiber coherence, and fiber density‐ within an MRI voxel may be used to detect AD‐specific deficits. However, mechanisms driving loss of WM microstructural integrity in AD are poorly understood. Vascular endothelial growth factor (VEGF) is a multi‐function vascular protein linked to early AD brain and cognition biomarkers. VEGF provides neurotrophic support via glia and is also secreted by glial cells essential for maintaining myelin. However, in humans, the relationship between VEGF and WM microstructural integrity has yet to be mapped. We evaluated whether cerebrospinal fluid (CSF) VEGF levels were associated with voxelwise WM FA in older adults without dementia.MethodWe evaluated 72 older adults without dementia from the USC Alzheimer’s Disease Research Center (ADRC) (mean age 65.7; 47‐82 years old) with a clinical dementia rating (CDR) score of 0 (n=56) or 0.5 (n=16) who had both CSF VEGF‐A levels and a 3 T diffusion MRI scan (64‐direction (b=1000 s/mm2) DWI volumes). MRI scans were pre‐processed to reduce artifacts related to motion, distortion, eddy currents, bias field, and susceptibility artifacts. Tract‐based spatial statistics, using FSL software, was implemented to derive skeletonized FA maps along WM tracts. The association between VEGF and voxelwise FA WM integrity was evaluated using FSL’s general linear model tool. We covaried for age, sex, and CDR. FA significance cluster maps were corrected for voxelwise multiple comparisons.ResultHigher CSF VEGF levels were associated with lower DTI FA, indicative of poorer WM microstructural integrity, in the left and right superior longitudinal fasciculus, left anterior thalamic radiation, and left inferior frontal occipital fasciculus (p&lt;0.05) (Figure 1).ConclusionThese results demonstrate for the first time in humans that VEGF levels are related to WM microstructure in older adults without dementia, primarily in long range association fibers connecting temporal, parietal, and frontal lobes. These pathways are essential for memory, language, attention and emotional control.

Association of Blood Biomarkers of Inflammation With Penumbra Consumption After Mechanical Thrombectomy in Patients With Acute Ischemic Stroke.

The objective of this study was to assess the relationship between blood biomarkers of inflammation and lesion growth within the penumbra in acute ischemic stroke (AIS) patients treated with mechanical thrombectomy (MT). The HIBISCUS-STROKE cohort enrolled patients admitted in the Lyon Stroke Center for an anterior circulation AIS treated with MT after brain MRI assessment. Lesion growth within the penumbra was assessed on day 6 MRI using a voxel-based nonlinear coregistration method and dichotomized into low and high according to the median value. C-reactive protein, interleukin (IL)-6, IL-8, IL-10, monocyte chemoattractant protein-1, soluble tumor necrosis factor receptor I, soluble form suppression of tumorigenicity 2 (sST2), soluble P-selectin, vascular cellular adhesion molecule-1, and matrix metalloproteinase-9 were measured in sera at 4 time points within the first 48 hours. Reperfusion was considered as successful if Thrombolysis in Cerebral Infarction score was 2b/2c/3. A multiple logistic regression model was performed to detect any association between area under the curve (AUC) of these biomarkers within the first 48 hours and a high lesion growth within the penumbra. Ninety patients were included. The median lesion growth within the penumbra was 2.3 (0.7-6.2) mL. On multivariable analysis, a high sST2 AUC (OR 3.77, 95% CI 1.36-10.46), a high baseline DWI volume (OR 3.65, 95% CI 1.32-10.12), and a lack of successful reperfusion (OR 0.19, 95% CI 0.04-0.92) were associated with a high lesion growth within the penumbra. When restricting analyses to patients with successful reperfusion (n = 76), a high sST2 AUC (OR 5.03, 95% CI 1.64-15.40), a high baseline DWI volume (OR 3.74, 95% CI 1.22-11.53), and a high penumbra volume (OR 3.25, 95% CI 1.10-9.57) remained associated with a high lesion growth within the penumbra. High sST2 levels within the first 48 hours are associated with a high lesion growth within the penumbra.

Surrogate biomarkers of outcome for wake-up ischemic stroke

BackgroundWake-up ischemic stroke (IS) has been usually excluded from acute stroke therapy options for being outside of the safe treatment window. We identified risk factors, and clinical or molecular biomarkers that could be therapeutic targets for wake-up stroke prevention, thus hopefully leading to a decrease in its mortality and disability in medium to long-term outcome.Methods4251 ischemic stroke (IS) patients from a prospectively registered database were recruited; 3838 (90.3%) had known onset-symptom time, and 413 (9.7%) were wake-up strokes. The main endpoint was to analyze the association between different serum biomarkers with wake-up IS episodes and their progression. Leukocytes count, serum levels of C-reactive protein, fibrinogen, interleukin 6 (IL-6), and vitamin D were analyzed as inflammation biomarkers; N-terminal pro-B-type Natriuretic-Peptide and microalbuminuria, used as atrial/endothelial dysfunction biomarkers; finally, glutamate levels as excitotoxicity biomarker. In addition, demographic, clinical and neuroimaging variables associated with the time-evolution of wake-up IS patients and functional outcome at 3 months were evaluated. Good and poor functional outcome were defined as mRS ≤2 and mRS > 2 at 3 months, respectively.ResultsWake-up IS showed a poorer outcome at 3-months than in patients with known on-set-symptom time (59.1% vs. 48.1%; p < 0.0001). Patients with wake-up IS had higher levels of inflammation biomarkers; IL-6 levels at admission (51.5 ± 15.1 vs. 27.8 ± 18.6 pg/ml; p < 0.0001), and low vitamin D levels at 24 h (5.6 ± 5.8 vs. 19.2 ± 9.4 ng/ml; p < 0.0001) are worthy of attention. In a logistic regression model adjusted for vitamin D, OR was 15.1; CI 95%: 8.6–26.3, p < 0.0001. However, we found no difference in vitamin D levels between patients with or without clinical-DWI mismatch (no: 18.95 ± 9.66; yes: 17.84 ± 11.77 ng/mL, p = 0.394). No difference in DWI volume at admission was found (49.3 ± 96.9 ml in wake-up IS patients vs. 51.7 ± 98.2 ml in awake IS patients; p = 0.895).ConclusionsInflammatory biomarkers are the main factors that are strongly associated with wake-up IS episodes. Wake-up IS is associated with lower vitamin D levels. These data indicate that vitamin D deficiency could become a therapeutic target to reduce wake-up IS events.

Diabetes is an Independent Growth Factor of Ischemic Stroke During Reperfusion Phase Leading to Poor Clinical Outcome

ObjectivesDespite the success of recanalization by bridging therapy, about half of treated stroke patients remain disabled. While numerous reports propose clinical predictors of stroke clinical outcome in this context, we originally aimed to study pre-therapeutic factors influencing infarct growth (IG) and poor clinical outcome in strokes due to large vessel occlusion (LVO) successfully recanalized. Materials and methodsWe enrolled 87 consecutive successfully recanalized patients (mTICI: 2b/2c/3) by mechanical thrombectomy (±rt-PA) after stroke due to middle cerebral artery (M1) occlusion within 6 h according to AHA guidelines. IG was defined by subtracting the initial DWI volume to the final 24 h-TDM volume. Statistical associations between poor clinical outcome (mRS≥2), IG and pertinent clinico-radiological variables, were measured using logistic and linear regression models. ResultsAmong 87 enrolled patients (Age(y): 68.4 ± 17.5; NIHSS: 16.0 ± 5.4), 42/87 (48,28%) patients had a mRS ≥ 2 at 3 months. Diabetic history (OR: 3.70 CI95%[1.03;14.29] and initial NIHSS (/1 point: OR: 1.16 CI95%[1.05;1.27]) were independently associated with poor outcome. IG was significantly higher in stroke patients with poor outcome (+7.57 ± 4.52 vs −7.81 ± 1.67; p = 0.0024). Initial volumes were not significantly different (mRS≥2: 16.18 ± 2.67; mRS[0–1]: 14.70 ± 2.30; p = 0.6771). Explanatory variables of IG in linear regression were diabetic history (β: 21.26 CI95%[5.43; 37.09]) and NIHSS (β: 0.83 CI95%[0.02; 1.64]). IG was higher in diabetic stroke patients (23.54 ± 1.43 vs −6.20 ± 9.36; p = 0.0061). ConclusionsWe conclude that diabetes leads to continued IG after complete recanalization, conditioning clinical outcome in LVO strokes successfully recanalized by bridging therapy. We suggest that poor tissular reperfusion by diabetic microangiopathy could explain this result.

Abstract WP103: Comparison Of Acute Infarct Lesions Between Non-contrast CT, DWI And FLAIR Using Back-to-back Imaging

Introduction: Size and location of the acute infarct is a major determinant of stroke outcome and eligibility for therapy. Recently, there have been efforts to train deep learning networks to detect lesions on Non-Contrast CT (NCCT) using concurrent DWI imaging as the gold standard. However, little is known about the radiological correspondence between concurrent NCCT and DWI lesion sizes. We performed an exploratory analysis comparing the stroke lesion volume on acute NCCT to that on DWI and FLAIR images performed shortly after. Methods: Population: DEFUSE 3 trial patients scanned 6-16h after last known well with DWI and NCCT &lt;1h apart. NCCT was segmented using an algorithm detecting more than 5% depression compared to the contralateral homologous region. The DWIs and FLAIR were co-registered to NCCT and manually segmented in ITK-Snap. Results: Thirteen patients fulfilled inclusion criteria. DWI volumes were (median, [IQR]) 52 mL [39 - 102], FLAIR volumes 35 mL [18 - 66] and NCCT lesion volumes 14 mL [8 - 22]. NCCT lesions were significantly smaller than both DWI and FLAIR, p &lt; 0.001 and p &lt; 0.048. The Dice coefficient was 0.2 [0.1 - 0.3] for FLAIR vs NCCT and 0.3 [0.1 - 0.5] for DWI vs NCCT. Conclusion: NCCT lesion volumes were consistently smaller than both DWI and FLAIR lesions although the volumetric agreement with FLAIR lesions was better. Both FLAIR and NCCT are sensitive to influx of parenchymal water and as such may have more similar lesions than DWI imaging which is sensitive to early occurring intraparenchymal displacements. The findings suggest that the training of deep learning networks to detect early NCCT hypodensity should focus on FLAIR or expert outlines drawn directly on the NCCT rather than DWI as the gold standard.

Whole blood viscosity is associated with baseline cerebral perfusion in acute ischemic stroke

Whole blood viscosity (WBV) is the intrinsic resistance to flow developed due to the frictional force between adjacent layers of flowing blood. Elevated WBV is an independent risk factor for stroke. Poor microcirculation due to elevated WBV can prevent adequate perfusion of the brain and might act as an important secondary factor for hypoperfusion in acute ischaemic stroke. In the present study, we examined the association of WBV with basal cerebral perfusion assessed by CT perfusion in acute ischaemic stroke. Confirmed acute ischemic stroke patients (n = 82) presenting in hours were recruited from the single centre. Patients underwent baseline multimodal CT (non-contrast CT, CT angiography and CT perfusion). Where clinically warranted, patients also underwent follow-up DWI. WBV was measured in duplicate within 2 h after sampling from 5-mL EDTA blood sample. WBV was significantly correlated with CT perfusion parameters such as perfusion lesion volume, ischemic core volume and mismatch ratio; DWI volume and baseline NIHSS. In a multivariate linear regression model, WBV significantly predicted acute perfusion lesion volume, core volume and mismatch ratio after adjusting for the effect of occlusion site and collateral status. Association of WBV with hypoperfusion (increased perfusion lesion volume, ischaemic core volume and mismatch ratio) suggest the role of erythrocyte rheology in cerebral haemodynamic of acute ischemic stroke. The present findings open new possibilities for therapeutic strategies targeting erythrocyte rheology to improve cerebral microcirculation in stroke.

Objective criteria for MRI evaluation of the effectiveness of treatment of bone metastases in patients with prostate cancer and breast cancer: systematic review and meta-analysis

BACKGROUND: The possibility of a personalized approach to the treatment of metastatic prostate cancer and breast cancer requires objective methods for the evaluation of the response of foci treatment in the skeleton. The proven high efficiency of MRI in detecting bone metastases, in combination with the absence of ionizing radiation, has laid the groundwork for using this method in monitoring the treatment course based on objective criteria for evaluation of the therapeutic outcome.&#x0D; AIM: To assess the possibilities of quantitative and semi-quantitative parameters of MRI-evaluation of treatment efficacy (radiation, chemotherapy, hormone therapy, and targeted therapy) of bone metastases that were used in prostate and breast cancer clinical trials.&#x0D; MATERIALS AND METHODS: We searched the databases Embase, PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), eLibrary until April 1, 2021, using the following keywords: magnetic resonance imaging, MRI, DWI, treatment response, prostate or breast cancer, and bone metastasis. We only included studies related to the MRI-evaluation of treatment efficacy of any type of therapeutic intervention (with the exception of surgery) for metastatic skeletal lesions in this review.&#x0D; RESULTS: We selected and analyzed 11 out of 312 sources found as a result of the search. It allowed us to identify four groups of objective MRI criteria for evaluating the therapeutic effect in metastatic bone lesions in patients with prostate and breast cancer, including the dynamics of sizes, signal intensity on DWI, ADC, and tumor total diffusion volume (tDV). Changes in these quantitative and semi-quantitative indicators, with only one exception, had the same direction, although they differed in numerical values. A random-effects model was used for analysis considering the presence of statistically significant heterogeneity (p 0,1 for 2 test; I2 40%),. The change in ADC as a result of treatment averaged +0.35 [+0.12; +0.49] 103 mm2/s, with average values of ADC before treatment ― 0.83 [0.71; 1.03] 103 mm2/s, after treatment ― 1.18 [0.83; 1.49] 103 mm2/s.&#x0D; CONCLUSION: MRI is an informative technique for the objective evaluation of the response of bone metastases to therapy in patients with prostate cancer and breast cancer based on quantitative and semi-quantitative parameters. It has significant potential as a diagnostic test instrument for monitoring the effectiveness of treatment of metastatic skeletal lesions.

Cardiac Structure and Function Is Associated With Hemispatial Neglect Severity.

Background: Hemispatial neglect is a debilitating consequence of right hemispheric ischemic stroke (RIS), with evidence that patient-level factors influence neglect severity. Study objective: Determine if cardiac function is associated with presence and severity of neglect, independent of infarct size.Methods: Two hundred and eighteen non-demented, RIS with cerebral MRI and echocardiography who completed ≥1 of 4 tests evaluating neglect were included. Age- and sex- adjusted Z-scores defined neglect with severity categorized as no neglect, neglect on one or neglect on ≥2 tests. The dependent variable was presence of neglect (multivariable logistic regression), or neglect severity (multinomial logistic regression). The association with left ventricular (LV) structure/function (independent variable) was evaluated using separate nested adjustment models.Results: Patients were on average 61 yo (21–95), female (50%), black (53%), with an ejection fraction of 60% (IQR 20–75%). Fifty eight (27%) had neglect. Each 1 cm increase in LV systolic diameter was associated with a higher relative risk of having neglect on two tests compared to those with no neglect (RRR = 1.83, 95% CI 1.01–3.32), but not after adjusting for education and DWI volume (RRR = 1.68, 95% CI 0.89–3.19). Per 1 cm increase in left atrial (LA) diameter, the relative risk of having neglect on 2 tests vs. no neglect was over two times higher (95% CI 1.04–4.77), but lost significance in the final model (RRR = 1.73, 95% CI 0.76–3.94).Conclusions: We found an association between markers of diastolic dysfunction (enlarging LV, compensatory enlarging LA) and severity of neglect, suggesting that cardiac structure, and function affects not only lesion volume, but also the functional consequences of infarct volume.

Non-contrast dual-energy CT virtual ischemia maps accurately\xa0estimate\xa0ischemic core size\xa0in large-vessel occlusive\xa0stroke

Dual-energy CT (DECT) material decomposition techniques may better detect edema within cerebral infarcts than conventional non-contrast CT (NCCT). This study compared if Virtual Ischemia Maps (VIM) derived from non-contrast DECT of patients with acute ischemic stroke due to large-vessel occlusion (AIS-LVO) are superior to NCCT for ischemic core estimation, compared against reference-standard DWI-MRI. Only patients whose baseline ischemic core was most likely to remain stable on follow-up MRI were included, defined as those with excellent post-thrombectomy revascularization or no perfusion mismatch. Twenty-four consecutive AIS-LVO patients with baseline non-contrast DECT, CT perfusion (CTP), and DWI-MRI were analyzed. The primary outcome measure was agreement between volumetric manually segmented VIM, NCCT, and automatically segmented CTP estimates of the ischemic core relative to manually segmented DWI volumes. Volume agreement was assessed using Bland–Altman plots and comparison of CT to DWI volume ratios. DWI volumes were better approximated by VIM than NCCT (VIM/DWI ratio 0.68 ± 0.35 vs. NCCT/DWI ratio 0.34 ± 0.35; P < 0.001) or CTP (CTP/DWI ratio 0.45 ± 0.67; P < 0.001), and VIM best correlated with DWI (rVIM = 0.90; rNCCT = 0.75; rCTP = 0.77; P < 0.001). Bland–Altman analyses indicated significantly greater agreement between DWI and VIM than NCCT core volumes (mean bias 0.60 [95%AI 0.39–0.82] vs. 0.20 [95%AI 0.11–0.30]). We conclude that DECT VIM estimates the ischemic core in AIS-LVO patients more accurately than NCCT.

Abstract P331: Accuracy of CT Perfusion Core Estimates for Predicting Infarct Size in the SELECT Study

Background: The accuracy of CT perfusion imaging for estimating the ischemic core has been questioned. Methods: In SELECT, a prospective cohort study of imaging selection, pts who achieved complete reperfusion after EVT were stratified on time from LKW to imaging acquisition and time from imaging to reperfusion. The difference between baseline CTP core volume and f/up infarct volume (on DWI after EVT) was classified as over-estimation (core &gt;10 cc larger than infarct), adequate, or under-estimation (≥ 25 cc smaller). F/up DWI lesion was outlined using a semiautomated algorithm and co-registered to CTP. Results: Of 361 enrolled, 117 achieved TICI 3. F/up MRIs were acquired at 21 (13-30) hrs from EVT with median infarct volume of 16.4 cc, median 8.1 cc larger than baseline core. Median (IQR) time from imaging acquisition to groin puncture (GP) was 70 (50-95) min. Reperfusion was achieved at 35 (25-54) min of GP. The frequency of overestimation decreased as time LKW to imaging increased: &lt; 90 min 6 (14%), 90 – 270 min 3 (6%) and &gt; 270 min 1 (4%), and adequate estimation increased (&lt; 90 min 21 (50%), 90 – 270 min 32 (65%) and &gt; 270min 19 (73%), p for trend 0.048) Fig 1. Overestimation primarily occurred in pts imaged within 90 min who had short imaging to reperfusion times Fig 2. Volumetric correlation between pre-procedure and f/up imaging improved as LKW time to imaging acquisition increased; Spearman’s ρ: &lt;90 min: 0.41 (p=0.007), 90-270 min: 0.35 (p=0.01), &gt;270 min: 0.79 (p&lt;0.0001). Spatially, overestimation occurred predominantly in white matter juxtacortical areas. Adjusting rCBF threshold from &lt; 30% to &lt; 20% in the 6 pts with overestimation ≤ 90 min from LKW resulted in adequate core estimation in all 6, Fig 3. Conclusion: In patients who achieve reperfusion, the correlation between baseline CTP ischemic core volume and f/up DWI volume improved as time LKW to imaging increased. Core estimation accuracy improved by using the &lt; 20% CBF threshold for patients imaged within 90 minutes of LKW.

Soluble Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 Level is Related to Clinical Prognosis In Patients with Acute Atherosclerosis-related Ischemic Stroke.

To investigate the associations between soluble Lectin-like Oxidized Low-density lipoprotein receptor-1 (sLOX-1) and clinical prognosis, especially infarct volume in patients with acute atherosclerosis-related ischemic stroke. We recruited acute ischemic stroke patients within 3 days after onset. Patients were stratified into 3 groups by sLOX-1 level. Initial stroke severity was assessed using the National Institutes of Health Stroke Scale scores, and infarct volume was measured using DWI by ITK-SNAP software. The clinical prognosis was evaluated by DWI volume, clinical response at discharge, and functional outcome at 90 days. Spearman rank correlation analysis was used to examine associations between circulating sLOX-1 levels and infarct volumes. Logistic regression was used to explore the relationship between sLOX-1 levels and clinical prognosis. A total of 207 patients were included in our study. The median DWI volume in the lowest sLOX-1 tertile was 1.98 cm3, smaller than 4.26 cm3 in the highest sLOX-1 group. The Spearman rank correlation coefficient between sLOX-1 levels and DWI volume was 0.47 (P < .01). Compared with the highest sLOX-1 tertiles, patients in the lowest sLOX-1 tertile had a higher risk of favorable functional outcome at 90 days (OR = 3.47, 95% CI, 1.21-9.96) after adjusting traditional risk factors. However, there was no difference between sLOX-1 level and clinical response at discharge. For patients with acute atherosclerosis-related ischemic stroke, circulating sLOX-1 level is correlated with DWI volume in the acute phase and favorable functional outcome at 90 days, but not with the clinical response at discharge.

Automatic Segmentation of Prostate Cancer using cascaded Fully Convolutional Network

In this paper we proposed a prostate segmentation and also tumour detection using deep neural networks. The cutting-edge deep learning techniques are useful compared to the challenges of machine learning based feature extraction techniques. Here we proposed a strategy that contains an FCN model that incorporates data from several MRI images, allowing for faster convergence and more accurate segmentation. T1 and DWI volumes may be used together to delineate the prostate boundary, according to this study. Second, we investigated whether this method might be utilized to provide voxel-level prostate tumor forecasts. The cascaded learning method and performed tests to demonstrate its effectiveness.

Abstract WMP18: Global White Matter Microstructural Injury Predicts Poor Outcomes After Ischemic Stroke

Background: Early outcome prediction after acute ischemic stroke (AIS) is critical to guide care and rehabilitation strategies. Pre-existing chronic structural injury to cerebral white matter (WM), including ischemic WM hyperintensity (WMH) and microstructural changes within the normal-appearing WM (NAWM), is known to impede post-stroke recovery. Quantitative assessment of total pre-existing WM injury may therefore improve prognostication of functional stroke outcomes. Peak width of skeletonized mean diffusivity (PSMD) is an automated marker of cerebral small vessel disease and global WM injury. In a cohort of AIS patients, we measured PSMD in the hemisphere contralateral to the acute infarct and characterized its association with 90-day functional outcomes. Methods: Brain MRI with diffusion tensor imaging sequences was acquired within 48 hours of AIS admission. WMH volume (WMHv) was measured in a semi-automated manner. NAWM masks were constructed by subtracting the WMH and chronic infarct masks from a probabilistic WM atlas. NAWM mean diffusivity (MD) was then measured in the NAWM mask. PSMD was extracted by skeletonizing the WM tracts in the MD image using the Fractional Anisotropy image and the FSL Tract-Based Spatial Statistics pipeline with a mask for the contralesional hemisphere. Excellent outcome was defined as a modified Rankin scale score &lt; 2 at 3-6 months post-stroke. Logistic regression analysis was performed to evaluate predictors of excellent outcome. Results: In 292 AIS patients, increasing PSMD and NAWM MD, but not WMHv, were associated with decreased likelihood of excellent outcome in univariable analysis. Increasing age, admission NIHSS score, DWI volume, and female sex were also negatively associated with excellent outcome. In backward stepwise logistic regression, including all significant variables from the univariable step, increasing age (β = -0.03; P = 0.01), NIHSS (β = -0.1; P = 0.0005), DWI volume (β = -0.02; P = 0.0004), PSMD (β = -0.08; P = 0.03), and female sex (β = -0.7; P = 0.01) were associated with decreased likelihood of excellent outcome. Conclusion: In AIS patients, automated determination of contralesional PSMD, as a marker of chronic, global white matter injury, is an independent predictor of functional outcomes.