Wintermark, Max

Background: Patients with acute ischemic stroke secondary to distal and medium vessel occlusion (AIS-DMVO) and minor strokes present a challenge in determining the most appropriate emergent treatment. Factors leading to early neurological deterioration (END) in this patient population are understudied, but END is known to result in poor functional outcomes. Therefore, we aimed to investigate the factors contributing to END in minor AIS-DMVO cases. Methods: We included patients with AIS-DMVO and minor strokes from 37 sites across North America, Asia, and Europe. Minor stroke was defined as a baseline National Institutes of Health Stroke Scale (NIHSS) score of ⩽5. The primary outcome measure, END, was defined as a shift of ⩾4 points in the NIHSS score at day one after treatment compared to baseline. Univariable and multivariable logistic regression analyses were performed to identify factors associated with END. Results: Among 559 consecutive patients with DMVO and minor strokes, END was reported in 68 patients. In multivariable analysis, mechanical thrombectomy (MT) was independently associated with higher odds of END (adjusted odds ratio [aOR] 2.37, 95% CI 1.12–5.02, p = 0.02), while intravenous thrombolysis (IVT) was associated with lower odds of END (aOR 0.46, 95% CI 0.26–0.81, p = 0.008). However, the association between MT and END was no longer statistically significant in the IPTW-adjusted analysis (OR 1.65, 95% CI 0.69–3.98, p = 0.26). Hypertension and antiplatelet use at baseline were also independently associated with END. Among MT-treated patients, successful and excellent recanalization and first-pass effect were protective against END. Conclusion: MT was associated with END in patients with minor AIS-DMVO, although this association was not significant after IPTW adjustment. IVT was independently associated with reduced risk of END. These findings support careful patient selection and further study in randomized trials.

Background Mechanical thrombectomy (MT) is established as an effective treatment for large vessel occlusion strokes, but its efficacy and safety for medium vessel occlusions (MeVOs) remain less clear. This study examines the impact of periprocedural embolization to a new vascular territory (ENT) on clinical outcomes in patients with MeVO stroke treated with MT. Methods A multicenter, retrospective analysis was conducted using the MAD-MT (Multicenter Analysis of primary Distal medium vessel occlusions: effect of Mechanical Thrombectomy) registry, including 2122 patients with MeVO stroke w­ho underwent MT between September 2017 and July 2023. ENT was defined as filling defects in previously unaffected territories, excluding embolization near the original occlusion, observed on final angiographic runs after retrieval of the primary thrombus. The associations between ENT, procedural variables, and 90-day clinical outcomes were evaluated, including functional independence (modified Rankin Scale (mRS) scores of 0–2), excellent outcomes (mRS 0–1), mortality, and hemorrhagic complications. Results ENT occurred in 2.9% (63/2122) of patients. Longer onset-to-arterial puncture time (adjusted OR 1.03; 95% CI 1.01 to 1.05; P=0.002) and a greater number of passes (adjusted OR 1.15; 95% CI 1.01 to 1.32; P=0.032) were associated with increased ENT risk, while excellent recanalization (thrombolysis in cerebral infarction (TICI) scale score 2c–3) was associated with reduced ENT risk (adjusted OR 0.41; 95% CI 0.23 to 0.72; P=0.002). ENT was not associated with poorer functional independence, mortality, or hemorrhagic complications. Conclusions ENT during MT for MeVO stroke occurs infrequently and does not significantly affect the clinical outcomes. These findings suggest ENT risk should not deter clinicians from performing MT in patients with MeVO. Further prospective studies are needed to validate these results.

Background Brain arteriovenous malformations (AVMs) are abnormal connections between feeding arteries and draining veins, associated with significant risks of haemorrhage, seizures and other neurological deficits. Preoperative embolization is commonly used as an adjunct to microsurgical resection, with the aim of reducing intraoperative complications and improving outcomes. However, the efficacy and safety of this approach remain controversial. Methods This study is a subanalysis of the Multicenter International Study for Treatment of Brain AVMs consortium. We retrospectively analysed 486 patients with brain AVMs treated with microsurgical resection between January 2010 and December 2023. Patients were divided into two groups: those who underwent microsurgery alone (n=245) and those who received preoperative embolization, followed by microsurgery (n=241). Propensity score matching was employed, resulting in 288 matched patients (144 in each group). The primary outcomes were rates of complete AVM obliteration and functional outcomes (measured by the modified Rankin Scale (mRS)). Secondary outcomes included complication rates, mortality, hospital length of stay and postsurgical rupture. Results After matching, the complete obliteration rate was 97% with no significant difference between the microsurgery-only group and the preoperative embolization group (p=0.12). The proportion of patients with an mRS score of 0–2 at the last follow-up was similar in both groups (83% vs 84%; p=0.67). The median hospital stay was significantly longer for the embolisation group (9 days vs 7 days; p=0.017). Complication rates (24% vs 22%; p=0.57) and mortality rates (4.9% vs 2.1%; p=0.20) were comparable between the two groups. No significant differences were observed in postsurgical rupture, recurrence or retreatment rates. Conclusions In this large multicentre study, preoperative embolization did not significantly improve AVM obliteration rates, functional outcomes or reduce complications compared with microsurgery alone.

Background: Acute ischemic stroke (AIS) from distal medium vessel occlusion (DMVO) presents unique treatment challenges. Mechanical thrombectomy (MT) is emerging as a viable option for these patients, yet the role of pre-stroke aspirin treatment is unclear. This study evaluates the impact of pre-stroke low-dose aspirin on outcomes in DMVO patients undergoing MT. Methods: We conducted a multinational, multicenter, propensity score-weighted analysis within the Multicenter Analysis of primary Distal medium vessel occlusions: effect of Mechanical Thrombectomy (MAD-MT) registry. Patients with AIS due to DMVO, treated with MT, were included. We compared outcomes between patients on pre-stroke low-dose aspirin (75–100 mg) and those not on antiplatelet therapy. The primary outcome was functional independence at 90 days (modified Rankin Scale (mRS), 0–2). Secondary outcomes included excellent functional outcome at 90 days (mRS, 0–1), mortality, and day 1 post-MT National Institutes of Health Stroke Scale (NIHSS) score. Safety outcomes focused on hemorrhagic complications, including symptomatic intracerebral hemorrhage (sICH). Results: Among 1354 patients, 150 were on pre-stroke low-dose aspirin. After applying inverse probability of treatment weighting (IPTW), aspirin use was associated with significantly better functional outcomes (mRS, 0–2: odds ratio (OR) = 1.89, 95% confidence interval (CI) = 1.14 to 3.12) and lower 90-day mortality (OR = 0.56, 95% CI = 0.32 to 1.00). The aspirin group had lower NIHSS scores on day 1 (β = −1.5, 95% CI = −2.8 to −0.27). The sICH rate was not significantly different between the groups (OR = 0.92, 95% CI = 0.60 to 1.43). Conclusions: Pre-stroke low-dose aspirin was associated with improved functional outcomes and reduced mortality in patients with DMVO undergoing MT, without a significant increase in sICH. These findings suggest that low-dose aspirin may be safe and associated with more frequent excellent outcomes for this patient population. Further prospective studies are needed to validate these results and assess long-term outcomes.

Background Current randomized controlled trials are investigating the efficacy and safety of mechanical thrombectomy (MT) in patients with medium vessel occlusion (MeVO) stroke. Whether best medical management (MM) is more efficient than unsuccessful vessel recanalization during MT remains unknown. Methods This was a retrospective cohort study using data from 37 academic centers across North America, Asia, and Europe between September 2017 and July 2021. Only patients with occlusion of the distal branches (M2 and M3) of the middle cerebral artery territory were included. Unsuccessful MT was defined as a modified Thrombolysis in Cerebral Infarction score of 0–2a. Propensity score matching was used to control for confounders. The primary outcome was functional independence, defined as a modified Rankin Scale (mRS) score of 0–2 at 90 days after treatment. Multivariable regression analysis was used to assess factors associated with the primary outcome. Results Of 2903 patients screened for eligibility, 532 patients were analyzed (266 per group) after propensity score matching. The MM group had superior functional outcomes, with 32% achieving mRS 0–1 at 90 days compared with 21% in the MT group (P=0.011). Patients in the MM group also had significantly lower rates of symptomatic intracranial hemorrhage (sICH) (3.4% vs 16%, P<0.001) and any hemorrhage (18% vs 48%, P<0.001). On multivariable regression, unsuccessful MT was associated with reduced odds of functional independence (OR 0.50, 95% CI 0.29 to 0.85, P=0.011) and increased odds of sICH (OR 4.32, 95% CI 1.84 to 10.10, P<0.001). Mortality rates were similar between groups (27% in MM vs 29% in MT, P=0.73). Conclusion Unsuccessful MT for MeVO was linked to worse outcomes than best MM. These findings highlight the risks of prolonged attempts and emphasize the importance of efficient procedural decision-making to reduce complications and improve patient outcomes.

Introduction In the current paper, the “carotid artery calcium score” method is presented with the target to offer a metric method to quantify the amount of calcification in the carotid artery. Model and Definition The Volume of Interest (VOI) should be extracted and those voxels, with a Hounsfield Unit (HU) value ≥130, should be considered. The total weight value is determined by calculating the sum of the HU attenuation values of all voxels with values ≥130 HU. This value should be multiplied by the conversion factor (“or voxel size”) and divided by a weighting factor, the attenuation threshold to consider a voxel as calcified (and therefore 130 HU): this equation determines the Carotid Artery Calcium Score (CACS). Results In order to provide the demonstration of the potential feasibility of the model, the CACS was calculated in 131 subjects (94 males; mean age 72.7 years) for 235 carotid arteries (in 27 subjects, unilateral plaque was present) considered. The CACS value ranged from 0.67 to 11716. A statistically significant correlation was found (rho value = 0.663, p value = .0001) between the CACS in the right and left carotid plaques. Moreover, a statistically significant correlation between the age and the total CACS was present (rho value = 0.244, p value = .005), whereas no statistically significant difference was found in the distribution of CACS by gender ( p = .148). The CACS was also tested at baseline and after contrast and no statistically significant difference was found. Conclusion In conclusion, this method is of easy application, and it weights at the same time the volume and the degree of calcification in a unique parameter. This method needs to be tested to verify its potential utility, similar to the coronary artery calcium score, for the risk stratification of the occurrence of cerebrovascular events of the anterior circulation. Further studies using this new diagnostic tool to determine the prognostic value of carotid calcium quantification are needed.

Objective: Aneurysm growth is considered predictive of future rupture of intracranial aneurysms. However, it is still unknown how accurately neuroradiologists can reliably detect incremental aneurysm growth using clinical magnetic resonance imaging (MRI) imaging. The purpose of this study is to assess the agreement rate of detecting aneurysm enlargement using generally used MRI imaging modalities. Methods: Three silicone flow phantom models each with eight aneurysms of various sizes in different sites were used in this study. The aneurysm models were identical except for an incremental increase in size of the 8 aneurysms ranging from 0.4mm to 2mm. The phantoms were imaged on 1.5 tesla (T) and 3T MRI units with both time-of-flight (TOF) and contrast enhanced magnetic resonance angiography (MRA). Three independent expert neuroradiologists measured the aneurysms in a blinded fashion utilizing different measurement approaches. The individual and agreement rate among the three experts in detecting aneurysm enlargement were calculated. Results: The average detection rate of any increase in any aneurysmal dimensions was 95.7%. The detection rate for the three readers (A, B and C) was 98.0%, 96.6% and 92.7%, respectively ( P =0.22). The detection rate in each MRI modality was 91.3% using 1.5 T TOF, 97.2% using 1.5T gadolinium (Gad), 95.8% using 3.0T TOF and 97.2% using 3.0T Gad ( P =0.31). As the incremental enlargement value increased, the detection rate for aneurysm enlargement increased. Use of Gad in 1.5T improved the detection rate in small incremental enlargement (e.g. 0.4 - 1mm) of the aneurysm ( P =0.04). The locations of the aneurysms also affected detection rate for aneurysm enlargement ( P <0.0001). Conclusions: The detection rate and interobserver agreement was very high for aneurysm enlargement of 0.4mm to 2 mm. Detection rate of any increase in any aneurysmal dimensions did not depend on the choice of MRI imaging modalities and measurement protocols.

OBJECTIVEAneurysm growth is considered predictive of future rupture of intracranial aneurysms. However, how accurately neuroradiologists can reliably detect incremental aneurysm growth using clinical MRI is still unknown. The purpose of this study was to assess the agreement rate of detecting aneurysm enlargement employing generally used MRI modalities.METHODSThree silicone flow phantom models, each with 8 aneurysms of various sizes at different sites, were used in this study. The aneurysm models were identical except for an incremental increase in the sizes of the 8 aneurysms, which ranged from 0.4 mm to 2 mm. The phantoms were imaged on 1.5-T and 3-T MRI units with both time-of-flight (TOF) and contrast-enhanced MR angiography. Three independent expert neuroradiologists measured the aneurysms in a blinded manner using different measurement approaches. The individual and agreement detection rates of aneurysm enlargement among the 3 experts were calculated.RESULTSThe mean detection rate of any increase in any aneurysmal dimension was 95.7%. The detection rates of the 3 observers (observers A, B, and C) were 98.0%, 96.6%, and 92.7%, respectively (p = 0.22). The detection rates of each MRI modality were 91.3% using 1.5-T TOF, 97.2% using 1.5-T with Gd, 95.8% using 3.0-T TOF, and 97.2% using 3.0-T with Gd (p = 0.31). On the other hand, the mean detection rate for aneurysm enlargement was 54.8%. Specifically, the detection rates of observers A, B, and C were 49.0%, 46.1%, and 66.7%, respectively (p = 0.009). As the incremental enlargement value increased, the detection rate for aneurysm enlargement increased. The use of 1.5-T Gd improved the detection rate for small incremental enlargement (e.g., 0.4–1 mm) of the aneurysm (p = 0.04). The location of the aneurysm also affected the detection rate for aneurysm enlargement (p < 0.0001).CONCLUSIONSThe detection rate and interobserver agreement were very high for aneurysm enlargement of 0.4–2 mm. The detection rate for at least 1 increase in any aneurysm dimension did not depend on the choice of MRI modality or measurement protocol. Use of Gd improved the accuracy of measurement. Aneurysm location may influence the accuracy of detecting enlargement.

The recent “Advanced Neuroimaging for Acute Stroke Treatment” meeting on September 7 and 8, 2007 in Washington DC, brought together stroke neurologists, neuroradiologists, emergency physicians, neuroimaging research scientists, members of the National Institute of Neurological Disorders and Stroke (NINDS), the National Institute of Biomedical Imaging and Bioengineering (NIBIB), industry representatives, and members of the US Food and Drug Administration (FDA) to discuss the role of advanced neuroimaging in acute stroke treatment. The goals of the meeting were to assess state-of-the-art practice in terms of acute stroke imaging research and to propose specific recommendations regarding: (1) the standardization of perfusion and penumbral imaging techniques, (2) the validation of the accuracy and clinical utility of imaging markers of the ischemic penumbra, (3) the validation of imaging biomarkers relevant to clinical outcomes, and (4) the creation of a central repository to achieve these goals. The present article summarizes these recommendations and examines practical steps to achieve them.