BACKGROUND AND PURPOSE: Iodine contrast extravasation (ICE) is common in patients with acute ischemic stroke (AIS) after endovascular-thrombectomy (EVT). The aim of our study was to evaluate the incidence of ICE assessed by dual-energy CT (DECT), its determinants, and associations with clinical outcome. MATERIALS AND METHODS: We retrospectively examined imaging parameters and clinical factors from consecutive patients with AIS treated with EVT who had a DECT 24 hours thereafter, identified at a single academic center. Associations between ICE, clinical, imaging, and procedural parameters, as well as clinical outcome were explored by using univariable and multivariable models. RESULTS: A total of 197 consecutive patients were included (period 2019–2020), of which 53 (27%) demonstrated ICE that was pure ICE in 30/53 (57%) and mixed with intracranial hemorrhage (ICH) in 23/53 (43%). Low initial-ASPECTS, high per-procedural-contrast volume injected, and high admission-glycemia were independently associated with ICE (respectively, OR = 0.43, 95% CI, 0.16–1.13, P = .047; OR = 1.02, 95% CI, 1.00–1.04, P = .003; OR = 8.92, 95% CI, 0.63–125.77, P = .043). ICE was independently associated with ICH (P = .047), but not with poorer clinical outcome (6-month mRS >2, P = .223). Univariate analysis demonstrated that low ADC, higher ischemic volume, ICA occlusion, mass effect, longer procedure duration, combined thrombectomy technique, higher number of device passes, and lower recanalization rate were associated with ICE (respectively, P = .002; <.001; .002; <.001; .002; 0.011; <0.001; 0.015). CONCLUSIONS: ICE evaluated with DECT is a relatively frequent finding after EVT, present in almost one-third of patients. Lower admission ASPECTS, higher glycemia, and high contrast volume injected per procedure were associated with ICE. We also found an association between ICE and ICH, confirming blood–brain barrier alteration as a major determinant of ICH.

OBJECTIVE: The pathogenesis of intracranial dural arteriovenous fistulas (icDAVFs) is controversial. Cerebral vein thrombosis (CVT) and venous hypertension are recognized predisposing factors. This study aimed to evaluate the incidence of association between icDAVF and CVT and describe baseline aggressiveness and clinical outcomes for icDAVFs associated with CVT. The authors also performed a literature review of studies reporting icDAVF associated with CVT. METHODS: Two hundred sixty-three consecutive patients in two university hospitals with confirmed icDAVFs were included. A double-blind imaging review was performed to determine the presence or absence of CVT close or distant to the icDAVF. Location, type (using the Cognard classification), aggressiveness of the icDAVF, clinical presentation, treatment modality, and clinical and/or angiographic outcomes at 6 months were also collected. All prior brain imaging was analyzed to determine the natural history of onset of the icDAVF. RESULTS: Among the 263 included patients, 75 (28.5%) presented with a CVT concomitant to their icDAVF. For 18 (78.3%) of 23 patients with previous brain imaging available, CVT preceding the icDAVF was proven (6.8% of the overall population). Former/active smoking (OR 2.0, 95% CI 1.079–3.682, p = 0.022) and prothrombogenic status (active inflammation or cancer/coagulation trouble) were risk factors for CVT associated with icDAVF (OR 3.135, 95% CI 1.391–7.108, p = 0.003). One hundred eighty-seven patients (71.1%) had a baseline aggressive icDAVF, not linked to the presence of a CVT (p = 0.546). Of the overall population, 11 patients (4.2%) presented with spontaneous occlusion of their icDAVF at follow-up. Seven patients (2.7%) died during the follow-up period. Intracranial DAVF + CVT was not associated with a worse prognosis (modified Rankin Scale score at 3–6 months: 0 [interquartile range {IQR} 0–1] for icDAVF + CVT vs 0 [IQR 0–0] for icDAVF alone; p = 0.055). CONCLUSIONS: This was one of the largest studies focused on the incidence of CVT associated with icDAVF. For 6.8% of the patients, a natural history of CVT leading to icDAVF was proven, corresponding to 78.3% of patients with previous imaging available. This work offers further insights into icDAVF pathophysiology, aiding in identifying high-risk CVT patients for long-term follow-up imaging. Annual imaging follow-up using noninvasive vascular imaging (CT or MR angiography) for a minimum of 3 years after the diagnosis of CVT should be considered in high-risk patients, i.e., smokers and those with prothrombogenic status.

In acute ischemic stroke with large vessel occlusion (AIS-LVO), interhospital transfer for endovascular therapy (EVT) provides an ideal therapeutic window during which neuroprotective strategies could be evaluated, allowing sufficient exposure before reperfusion. We aimed to determine whether blood-brain barrier (BBB) disruption assessed before interhospital transfer for EVT is associated with 24-hour hemorrhagic transformation (HT) and 3-month functional outcome. In this multicenter retrospective study, we included patients with anterior circulation AIS-LVO transferred from 4 French primary stroke centers (PSCs) to comprehensive stroke centers for EVT assessment, with baseline MR perfusion imaging performed at the PSC before transfer. BBB disruption was quantified as the percentage signal change due to gadolinium leakage on perfusion source images. Mean permeability derangement (MPD) was defined as the average of all voxels within the ischemic core exhibiting permeability values greater than a prespecified threshold. The primary outcome was any intraparenchymal HT on 24-hour follow-up imaging. The association between MPD and HT was studied in multivariable mixed binary logistic regression analyses. A total of 289 patients were included: the median age was 74 years (interquartile range 63-81), 49% were female, the median NIHSS score was 13 (7-19), the median last-seen-well-to-PSC imaging time was 2.5 hours (1.7-4.7), and the median core volume was 17 mL (0-40). Intravenous thrombolysis was administered before transfer in 71% of patients, and EVT was eventually performed in 71%. The median time from PSC imaging to comprehensive stroke center arrival was 3.3 hours (2.6-3.8). Any HT at 24 hours occurred in 129 patients (45%). In multivariable analysis, MPD ≥3% was independently associated with any HT (OR 6.58; 95% CI 2.84-15.22; p < 0.001) after adjustment for core volume, glucose level, occlusion site, onset-to-imaging time, and whether EVT was performed. Similar associations were observed for parenchymal hematoma (adjusted OR 3.31; 95% CI 1.48-7.41; p = 0.004) and poor 3-month functional outcome (modified Rankin Scale score 3-6, adjusted OR 3.13; 95% CI 1.38-7.09; p = 0.006). BBB disruption on pretransfer perfusion MRI is associated with 24-hour HT and poor 3-month functional outcome in patients with AIS-LVO. These findings highlight its potential value for early risk stratification and justify prospective evaluation of BBB-targeted strategies during interhospital transfer for EVT.

The widely used apparent diffusion coefficient (ADC) threshold of 620 × 10^-6 mm²/s to automatically delineate the ischemic core on diffusion-weighted imaging (DWI) was established in recanalized patients after IV thrombolysis. However, recanalization was assessed 3-6 hours after treatment, which may entail substantial core growth and in turn ADC threshold overestimation, while follow-up imaging was performed at day 30, implying potential infarct shrinkage. Other studies typically used follow-up MRI scans on days 2-5 but did not correct for vasogenic edema, implying potential infarct overestimation. We re-evaluated the ADC threshold in patients with very early recanalization after endovascular therapy (EVT), using 24-hour follow-up MRI and applying edema correction (EC). Consecutive patients with modified Treatment In Cerebral Infarction 2c-3 recanalization within 90 minutes after baseline MRI and who underwent follow-up MRI ≈24 hours were identified from our center's EVT registry (2012-2021). Basilar occlusions and small DWI lesions (<3 mL) were excluded. The baseline ischemic lesion and the final infarct (Infarct_24h) were manually delineated on initial DWI (DWI₀) and 24-hour DWI. EC was performed by applying nonlinear coregistration of follow-up MRI onto MRI₀. The intersection between DWI₀ and Infarct_24h was overlaid onto the baseline ADC map. A receiver operating characteristic analysis compared "core" with "noncore" voxels (obtained by varying the ADC threshold) across patients, and the Youden index was computed to determine the optimized ADC threshold (OptADC) without and with EC. Among 1,024 patients, 56 were eligible and included (median age 73 years; 52% female; median [interquartile range (IQR)] NIH Stroke Scale score 12 [8-19], median MRI₀-to-recanalization delay 70.5 [52-81] minutes). The OptADC was 611 × 10^-6 mm²/s (area under the curve = 0.704; sensitivity = 61.6%; specificity = 70.4%; Youden index = 0.320) and 612 × 10^-6 mm²/s without and with EC, respectively. The median (IQR) individual-OptADC was 621.5 (585.5-672.8) × 10^-6 mm²/s. The baseline core volume was significantly (p < 0.001), but only marginally, smaller using the optimized vs the reference ADC threshold (16.4 ± 25 mL and 17.0 ± 26 mL, respectively; volume difference larger than 3 mL in 1 patient only). We revisited the ADC core threshold using a stringent methodology, including EVT-induced ultra-early documented complete recanalization, ≈24-hour follow-up MRI, and EC. The resulting OptADC was marginally smaller than the reference threshold and, accordingly, modestly influenced the measured baseline core volume. The methodological refinements implemented here, including EC, seem essential for future research exploring core ADC.