BACKGROUND AND PURPOSE—Absence of arterial wall enhancement (AWE) of unruptured intracranial aneurysms (UIA) has shown promise at predicting which aneurysms will not rupture. We here tested the ...hypothesis that increased enhancement during follow-up (increased intensity, extension, or thickness or appearance of de novo enhancement), assessed using vessel wall magnetic resonance imaging, was associated with higher rates of subsequent growth.
METHODS—Patients with UIA were included between 2012 and 2018. Two readers independently rated AWE modification on 3T vessel wall magnetic resonance imaging, and morphological changes on time-of-flight magnetic resonance angiography during follow-up.
RESULTS—A total of 129 patients harboring 145 UIA (mean size 4.1 mm) met study criteria, of which 12 (8.3%) displayed morphological growth at 2 years. Of them, 8 demonstrated increased AWE during follow-up before or concurrently to morphological growth, and 4 had preexisting AWE that remained stable before growth. In the remaining 133 (nongrowing) UIAs, no AWE modifications were found. In multivariable analysis, increased AWE, not size, was associated with UIA growth (relative risk, 26.1 95% CI, 7.4–91.7, P<0.001). Sensitivity, specificity, positive predictive value, and negative predictive value for UIA growth of increased AWE during follow-up were, respectively, of 67%, 100%, 96%, and 100%.
CONCLUSIONS—Increased AWE during follow-up of conservatively managed UIAs predicts aneurysm growth over a 2-year period. This may impact UIA management towards closer monitoring or preventive treatment. Replication in a different setting is warranted.
BACKGROUND AND PURPOSE—The extent of diffusion lesion on pretreatment imaging is a risk factor for poor outcome and hemorrhagic transformation after thrombolysis, and volumes of 70 to 100 mL have ...been advocated as cut-offs. However, estimating diffusion-weighted imaging (DWI) lesion volume (VolDWI) in the acute setting may be cumbersome. We aimed to determine whether the DWI-Alberta Stroke Program Early CT Score (DWI-ASPECTS) can substitute for VolDWI.
METHODS—DWI-ASPECTS and VolDWI were measured retrospectively on pretreatment MRI (median onset-to-MRI delay=122 minutes) in 330 consecutively treated patients with middle cerebral artery stroke.
RESULTS—DWI-ASPECTS and VolDWI were strongly correlated (ρ=−0.82), but each DWI-ASPECTS point corresponded to a wide range of VolDWI. All patients with DWI-ASPECTS ≥7 (n=207) had VolDWI <70 mL, whereas 32 of the 34 patients with DWI-ASPECTS <4 had VolDWI >100 mL. However, intermediate DWI-ASPECTS (4–6; n=89) corresponded to highly variable VolDWI (median, 66 mL; interquartile range, 40–98).
CONCLUSIONS—Although each DWI-ASPECTS point corresponds to a wide range of volumes, DWI-ASPECTS <4 or ≥7 may be used as reliable surrogates of VolDWI >100 or <70 mL, respectively.
BACKGROUND AND PURPOSE—Fluid-attenuated inversion recovery vascular hyperintensities (FVH) beyond the boundaries of diffusion-weighted imaging (DWI) lesion (FVH-DWI mismatch) have been proposed as an ...alternative to perfusion-weighted imaging (PWI)-DWI mismatch. We aimed to establish whether FVH-DWI mismatch can identify patients most likely to benefit from recanalization.
METHODS—FVH-DWI mismatch was assessed in 164 patients with proximal middle cerebral artery occlusion before intravenous thrombolysis. PWI-DWI mismatch (PWITmax>6sec/DWI>1.8) was assessed in the 104 patients with available PWI data. We tested the associations between 24-hours complete recanalization on magnetic resonance angiography and 3-month favorable outcome (modified Rankin Scale score ≤2), stratified on FVH-DWI (or PWI-DWI) status.
RESULTS—FVH-DWI mismatch was present in 121/164 (74%) patients and recanalization in 50/164 (30%) patients. The odds ratio for favorable outcome with recanalization was 16.2 (95% confidence interval, 5.7–46.5; P<0.0001) in patients with FVH-DWI mismatch and 2.6 (95% confidence interval, 0.6–12.1; P=0.22) in those without FVH-DWI mismatch (P=0.048 for interaction). Recanalization was associated with favorable outcome in patients with PWI-DWI mismatch (odds ratios, 9.9; 95% confidence interval, 3.1–31.3; P=0.0001) and in patients without PWI-DWI mismatch (odds ratios, 7.0; 95% confidence interval, 1.1–44.1; P=0.047), P=0.76 for interaction.
CONCLUSION—The FVH-DWI mismatch may rapidly identify patients with proximal occlusion most likely to benefit from recanalization.
BACKGROUND AND PURPOSE—To propose a T2*-MR adaptation of the computed tomography angiography-clot burden score (CBS), and assess its value as predictor of 24-hour recanalization and clinical outcome ...in anterior circulation stroke treated by intravenous thrombolysis ≤4.5 hours from onset.
METHODS—Two independent observers retrospectively analyzed pretreatment T2* images for evaluation of clot burden, using a 10-point scale T2*-CBS. Three points are subtracted for susceptibility vessel sign in the supraclinoid internal carotid artery, 2 points each for susceptibility vessel sign in the proximal and distal part of middle cerebral artery, and 1 point each for susceptibility vessel sign in middle cerebral artery branches (with a maximum of 2 points) and for susceptibility vessel sign in anterior cerebral artery. Associations with 24-hour recanalization and favorable outcome (3-month modified Rankin Scale score, ≤2) were assessed in multivariate analyses.
RESULTS—We analyzed 184 consecutive patients (mean age, 67 years) with median (interquartile range) admission National Institutes of Health Stroke Scale score and onset-to-treatment time of 15 (9–19) and 151 (120–185) minutes, respectively. The intraclass correlation for T2*-CBS between observers was 0.97 (95% confidence interval, 0.97–0.98). In multivariate analyses, T2*-CBS >6 was significantly associated with 24-hour recanalization (adjusted odds ratio, 5.1 1.9–13.5; P=0.001) or with favorable outcome (adjusted odds ratio, 4.2 1.7–10.8; P=0.003).
CONCLUSIONS—T2*-CBS, a new reproducible semiquantitative score adapted from the computed tomography angiography-CBS, is associated with 24-hour recanalization and 3-month outcome after intravenous thrombolysis. This score needs external validation and could be useful to identify poor responders to intravenous thrombolysis.
BACKGROUND AND PURPOSE—Unstable clinical course characterizes the first 24 hours after thrombolysis for anterior circulation stroke, including early neurological deterioration (END), a secondary ...complication consistently predictive of poor outcome. Apart from straightforward causes, such as intracerebral hemorrhage and malignant edema, the mechanism of END remains unclear in the majority of cases (ENDunexplained). Based on the core/penumbra model, we tested the hypothesis that ENDunexplained is caused by infarct growth beyond the initial penumbra and assessed the associated vascular patterns.
METHODS—From our database of consecutive thrombolyzed patients (n=309), we identified 10 ENDunexplained cases who had undergone both admission and 24-hour MRI. Diffusion-weighted imaging lesion growth both within and beyond the acute penumbra (Tmax>6 seconds) was mapped voxelwise. These 10 cases were compared with 30 no-END controls extracted from the database blinded to 24-hour diffusion-weighted imaging to individually match cases (3/case) according to 4 previously identified clinical and imaging variables.
RESULTS—As predicted, lesion growth beyond initial penumbra was present in 9 of 10 ENDunexplained patients (substantial in 8) and its volume was significantly larger in cases than controls (2P=0.047). All ENDunexplained cases had proximal arterial occlusion initially, of which only 2 had recanalized at 24 hours.
CONCLUSIONS—In this exploratory study, most instances of ENDunexplained were related to diffusion-weighted imaging growth beyond acute penumbra. Consistent presence of proximal occlusion at admission and lack of recanalization at 24 hours in most cases suggest that hemodynamic factors played a key role, via for instance systemic instability/collateral failure or secondary thromboembolic processes. Preventing END after tissue-type plasminogen activator using, eg, early antithrombotics may therefore be feasible.
BACKGROUND AND PURPOSE—Whether to withhold recanalization treatment when the diffusion-weighted imaging (DWI) lesion exceeds a given volume is unsettled. Our aim was to assess the impact of ...recanalization on outcome in patients with baseline DWI lesion ≥70 mL (DWI≥70 mL) treated ≤4.5 hours from onset. We hypothesized that recanalization is beneficial in a sizeable fraction of these patients and that this is associated with a larger DWI lesion reversal.
METHODS—We analyzed 267 consecutive patients treated with intravenous recombinant tissue-type plasminogen activator for middle cerebral artery territory stroke in whom an occlusion was present on magnetic resonance angiography and 24-hour recanalization and 90-day clinical outcome could be assessed. After stratification relative to the 70-mL DWI lesion cut point, we calculated the odds ratio for recanalization of the primary arterial occlusive lesion (AOL score ≥2) to predict favorable outcome (modified Rankin scale score ≤2). DWI lesion reversal was compared between recanalizers with DWI≥70 mL with favorable and unfavorable outcomes.
RESULTS—Median (interquartile range) DWI lesion volume was 22 mL (10–60), and median onset time to imaging was 116 minutes (86–151). Twelve (22%) of the 54 patients with DWI≥70 mL experienced favorable outcome, of which 9 had recanalized. In patients with DWI≥70 mL, recanalization was significantly associated with favorable outcome after adjustment for age and National Institutes of Health Stroke Scale (odds ratio =4.72 1.09–20.32; P=0.0375). Among recanalizers with DWI≥70 mL, absolute and relative DWI reversal volumes were larger in those with favorable as compared with unfavorable outcome (18.8 mL 12.2–47.6 versus 8.5 mL 4.3–31.1; P=0.17; and 19.6% 10.9–62.8 versus 8.7% 3.9–16.5, respectively; P=0.049).
CONCLUSIONS—Patients with DWI lesion volume ≥70 mL can benefit from recanalization after intravenous recombinant tissue-type plasminogen activator. This may partly reflect a larger amount of DWI lesion reversal.
BACKGROUND AND PURPOSE—In acute ischemic stroke, white matter (WM) is considered more resistant to infarction than gray matter (GM). To test this hypothesis, we compared the fate of WM and GM voxels ...belonging to the acute diffusion-weighted imaging (DWI) lesion, expecting WM voxels to be more prone to reversal after thrombolysis.
METHODS—Reversible acute DWI (RAD) lesion was defined voxel-wise as an acute lesion on initial DWI (DWI1) with no visible lesion on 24-hour DWI (DWI2). Only patients with RAD lesions >10 mL and >10% of DWI1 from our previously reported cohort were eligible. The core was defined as voxels hyperintense on DWI1 and DWI2. Semiautomated segmentation of DWI1, core, and RAD lesions, normalization into standard space, and WM/GM segmentation allowed calculations of WM/GM proportions in each region of interest using a voxel-counting algorithm.
RESULTS—Thirty patients were eligible (RAD lesion median volume interquartile range, 23.3 mL 19.1–35.0 mL; onset-to-treatment time, 134 minutes 105–185 minutes). WM voxels fraction was greater in RAD lesions than in the core (59.4% 52.8%–68.9% versus 49.6% 43.0%–57.5%; P=0.011). The proportion of reversibility was greater for WM than for GM voxels (60.8% 25.5%–88.7% versus 53.5% 21.1%–77.3%; P=0.02). The percentage of RAD lesions increased with the proportion of WM present in the acute DWI lesion (P<0.0001; R=0.67).
CONCLUSIONS—Acute DWI lesions predominantly involving WM may be more prone to reversal and, hence, to respond to therapy than their GM counterparts.
Background and Purpose—Whether all acute stroke patients with large vessel occlusion need to undergo intravenous thrombolysis before mechanical thrombectomy (MT) is debated as (1) the incidence of ...post-thrombolysis early recanalization (ER) is still unclear; (2) thrombolysis may be harmful in patients unlikely to recanalize; and, conversely, (3) transfer for MT may be unnecessary in patients highly likely to recanalize. Here, we determined the incidence and predictors of post-thrombolysis ER in patients referred for MT and derive ER prediction scores for trial design. Methods—Registries from 4 MT-capable centers gathering patients referred for MT and thrombolyzed either on site (mothership) or in a non MT-capable center (drip-and-ship) after magnetic resonance– or computed tomography–based imaging between 2015 and 2017. ER was identified on either first angiographic run or noninvasive imaging. In the magnetic resonance imaging subsample, thrombus length was determined on T2*-based susceptibility vessel sign. Independent predictors of no- ER were identified using multivariable logistic regression models, and scores were developed according to the magnitude of regression coefficients. Similar registries from 4 additional MT-capable centers were used as validation cohort. Results—In the derivation cohort (N=633), ER incidence was ≈20%. In patients with susceptibility vessel sign (n=498), no-ER was independently predicted by long thrombus, proximal occlusion, and mothership paradigm. A 6-point score derived from these variables showed strong discriminative power for no-ER (C statistic, 0.854) and was replicated in the validation cohort (n=353; C statistic, 0.888). A second score derived from the whole sample (including negative T2* or computed tomography–based imaging) also showed good discriminative power and was similarly validated. Highest grades on both scores predicted no-ER with >90% specificity, whereas low grades did not reliably predict ER. Conclusions—The substantial ER rate underlines the benefits derived from thrombolysis in bridging populations. Both prediction scores afforded high specificity for no-ER, but not for ER, which has implications for trial design.
A long clot, defined by a low (0-6) clot burden score (CBS) assessed by T2*-MR sequence, is associated with worse clinical outcome after intravenous thrombolysis (IVT) for acute ischemic stroke than ...is a small clot (CBS, 7-10). The added benefit of mechanical thrombectomy (MT) might be higher in patients with long clot. The aim of this pre-specified post hoc analysis of the THRombectomie des Artères CErebrales (THRACE) trial was to assess the association between T2*-CBS, successful recanalization and clinical outcome.
Of 414 patients randomized in the THRACE trial, 281 patients were included in this analysis. Associations between T2*-CBS and clinical outcome on the modified Rankin Scale (mRS) at 3 months were tested.
High T2*-CBS, i.e., small clot, was associated with a shift toward better outcome on the mRS; proportional odds ratio (POR) per point CBS was 1.19 (95% confidence interval CI, 1.05 to 1.34) in the whole population, 1.34 (95% CI, 1.13 to 1.59) in IVT group, and 1.04 (95% CI, 0.87 to 1.23) in IVTMT group. After adjustment for baseline prognostic variables, the effect of the full scale T2*-CBS was not statistically significant in the whole population and for the IVTMT group but remains significant for the IVT group (POR, 1.32; 95% CI, 1.11 to 1.58).
s A small clot, as assessed using T2*-CBS, is associated with improved outcome and may be used as a prognostic marker. Despite the worst outcome with long clot, the relative benefit of MT over IVT seemed to increase with low T2*-CBS and longer clot.
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