Perfusion Abnormalities on 24-Hour Perfusion Imaging in Patients With Complete Endovascular Reperfusion.

BACKGROUND: Perfusion abnormalities in the infarct and salvaged penumbra have been proposed as a potential reason for poor clinical outcome (modified Rankin Scale score >2) despite complete angiographic reperfusion (Thrombolysis in Cerebral Infarction [TICI3]). In this study, we aimed to identify different microvascular perfusion patterns and their association with clinical outcomes among TICI3 patients. METHODS: University Hospital Bern's stroke registry of all patients between February 2015 and December 2021. Macrovascular reperfusion was graded using the TICI scale. Microvascular reperfusion status was evaluated within the infarct area on cerebral blood volume and cerebral blood flow perfusion maps obtained 24-hour postintervention. Primary outcome was functional independence (90-day modified Rankin Scale score 0-2) evaluated with the logistic regression analysis adjusted for age, sex, and 24-hour infarct volume from follow-up imaging. RESULTS: Based on microvascular perfusion findings, the entire cohort (N=248) was stratified into one of the 4 clusters: (1) normoperfusion (no perfusion abnormalities; n=143/248); (2) hyperperfusion (hyperperfusion on both cerebral blood volume and cerebral blood flow; n=54/248); (3) hypoperfusion (hypoperfusion on both cerebral blood volume and cerebral blood flow; n=14/248); and (4) mixed (discrepant findings, eg, cerebral blood volume hypoperfusion and cerebral blood flow hyperperfusion; n=37/248). Compared with the normoperfusion cluster, patients in the hypoperfusion cluster were less likely to achieve functional independence (adjusted odds ratio, 0.3 [95% CI, 0.1-0.9]), while patients in the hyperperfusion cluster tended to have better outcomes (adjusted odds ratio, 3.3 [95% CI, 1.3-8.8]). CONCLUSIONS: In around half of TICI3 patients, perfusion abnormalities on the microvascular level can be observed. Microvascular hypoperfusion, despite complete macrovascular reperfusion, is rare but may explain the poor clinical course among some TICI3 patients, while a detrimental effect of hyperperfusion after reperfusion could not be confirmed.

Value of intravenous alteplase before thrombectomy among patients with tandem lesions and emergent carotid artery stenting: A subgroup analysis of the SWIFT DIRECT trial.

BACKGROUND AND PURPOSE: The value of intravenous thrombolysis (IVT) in eligible tandem lesion patients undergoing endovascular treatment (EVT) is unknown. We investigated treatment effect heterogeneity of EVT + IVT versus EVT-only in tandem lesion patients. Additional analyses were performed for patients undergoing emergent internal carotid artery (ICA) stenting. METHODS: SWIFT DIRECT randomized IVT-eligible patients to either EVT + IVT or EVT-only. Primary outcome was 90-day functional independence (modified Rankin Scale score 0-2) after the index event. Secondary endpoints were reperfusion success, 24 h intracranial hemorrhage rate, and 90-day all-cause mortality. Interaction models were fitted for all predefined outcomes. RESULTS: Among 408 included patients, 63 (15.4%) had a tandem lesion and 33 (52.4%) received IVT. In patients with tandem lesions, 20 had undergone emergent ICA stenting (EVT + IVT: 9/33, 27.3%; EVT: 11/30, 36.7%). Tandem lesion did not show treatment effect modification of IVT on rates of functional independence (tandem lesion EVT + IVT vs. EVT: 63.6% vs. 46.7%, non-tandem lesion EVT + IVT vs. EVT: 65.6% vs. 58.2%; p for interaction = 0.77). IVT also did not increase the risk of intracranial hemorrhage  among tandem lesion patients (tandem lesion EVT + IVT vs. EVT: 34.4% vs. 46.7%, non-tandem lesion EVT + IVT vs. EVT: 33.5% vs. 26.3%; p for interaction = 0.15). No heterogeneity was noted for other endpoints (p for interaction > 0.05). CONCLUSIONS: No treatment effect heterogeneity of EVT + IVT versus EVT-only was observed among tandem lesion patients. Administering IVT in patients with anticipated emergent ICA stenting seems safe, and the latter should not be a factor to consider when deciding to administer IVT before EVT.

Time to Treatment With Intravenous Thrombolysis Before Thrombectomy and Functional Outcomes in Acute Ischemic Stroke: A Meta-Analysis.

Importance: The benefit of intravenous thrombolysis (IVT) for acute ischemic stroke declines with longer time from symptom onset, but it is not known whether a similar time dependency exists for IVT followed by thrombectomy. Objective: To determine whether the benefit associated with IVT plus thrombectomy vs thrombectomy alone decreases with treatment time from symptom onset. Design, Setting, and Participants: Individual participant data meta-analysis from 6 randomized clinical trials comparing IVT plus thrombectomy vs thrombectomy alone. Enrollment was between January 2017 and July 2021 at 190 sites in 15 countries. All participants were eligible for IVT and thrombectomy and presented directly at thrombectomy-capable stroke centers (n = 2334). For this meta-analysis, only patients with an anterior circulation large-vessel occlusion were included (n = 2313). Exposure: Interval from stroke symptom onset to expected administration of IVT and treatment with IVT plus thrombectomy vs thrombectomy alone. Main Outcomes and Measures: The primary outcome analysis tested whether the association between the allocated treatment (IVT plus thrombectomy vs thrombectomy alone) and disability at 90 days (7-level modified Rankin Scale [mRS] score range, 0 [no symptoms] to 6 [death]; minimal clinically important difference for the rates of mRS scores of 0-2: 1.3%) varied with times from symptom onset to expected administration of IVT. Results: In 2313 participants (1160 in IVT plus thrombectomy group vs 1153 in thrombectomy alone group; median age, 71 [IQR, 62 to 78] years; 44.3% were female), the median time from symptom onset to expected administration of IVT was 2 hours 28 minutes (IQR, 1 hour 46 minutes to 3 hours 17 minutes). There was a statistically significant interaction between the time from symptom onset to expected administration of IVT and the association of allocated treatment with functional outcomes (ratio of adjusted common odds ratio [OR] per 1-hour delay, 0.84 [95% CI, 0.72 to 0.97], P = .02 for interaction). The benefit of IVT plus thrombectomy decreased with longer times from symptom onset to expected administration of IVT (adjusted common OR for a 1-step mRS score shift toward improvement, 1.49 [95% CI, 1.13 to 1.96] at 1 hour, 1.25 [95% CI, 1.04 to 1.49] at 2 hours, and 1.04 [95% CI, 0.88 to 1.23] at 3 hours). For a mRS score of 0, 1, or 2, the predicted absolute risk difference was 9% (95% CI, 3% to 16%) at 1 hour, 5% (95% CI, 1% to 9%) at 2 hours, and 1% (95% CI, -3% to 5%) at 3 hours. After 2 hours 20 minutes, the benefit associated with IVT plus thrombectomy was not statistically significant and the point estimate crossed the null association at 3 hours 14 minutes. Conclusions and Relevance: In patients presenting at thrombectomy-capable stroke centers, the benefit associated with IVT plus thrombectomy vs thrombectomy alone was time dependent and statistically significant only if the time from symptom onset to expected administration of IVT was short.

Thrombectomy versus Medical Management for Isolated Anterior Cerebral Artery Stroke: An International Multicenter Registry Study.

Background Evidence supporting a potential benefit of thrombectomy for distal medium vessel occlusions (DMVOs) of the anterior cerebral artery (ACA) is, to the knowledge of the authors, unknown. Purpose To compare the clinical and safety outcomes between mechanical thrombectomy (MT) and best medical treatment (BMT) with or without intravenous thrombolysis for primary isolated ACA DMVOs. Materials and Methods Treatment for Primary Medium Vessel Occlusion Stroke, or TOPMOST, is an international, retrospective, multicenter, observational registry of patients treated for DMVO in daily practice. Patients treated with thrombectomy or BMT alone for primary ACA DMVO distal to the A1 segment between January 2013 and October 2021 were analyzed and compared by one-to-one propensity score matching (PSM). Early outcome was measured by the median improvement of National Institutes of Health Stroke Scale (NIHSS) scores at 24 hours. Favorable functional outcome was defined as modified Rankin scale scores of 0-2 at 90 days. Safety was assessed by the occurrence of symptomatic intracerebral hemorrhage and mortality. Results Of 154 patients (median age, 77 years; quartile 1 [Q1] to quartile 3 [Q3], 66-84 years; 80 men; 94 patients with MT; 60 patients with BMT) who met the inclusion criteria, 110 patients (median age, 76 years; Q1-Q3, 67-83 years; 50 men; 55 patients with MT; 55 patients with BMT) were matched. DMVOs were in A2 (82 patients; 53%), A3 (69 patients; 45%), and A3 (three patients; 2%). After PSM, the median 24-hour NIHSS point decrease was -2 (Q1-Q3, -4 to 0) in the thrombectomy and -1 (Q1-Q3, -4 to 1.25) in the BMT cohort (P = .52). Favorable functional outcome (MT vs BMT, 18 of 37 [49%] vs 19 of 39 [49%], respectively; P = .99) and mortality (MT vs BMT, eight of 37 [22%] vs 12 of 39 [31%], respectively; P = .36) were similar in both groups. Symptomatic intracranial hemorrhage occurred in three (2%) of 154 patients. Conclusion Thrombectomy appears to be a safe and technically feasible treatment option for primary isolated anterior cerebral artery occlusions in the A2 and A3 segment with clinical outcomes similar to best medical treatment with and without intravenous thrombolysis. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Zhu and Wang in this issue.

Importance of Delayed Reperfusions in Patients With Incomplete Thrombectomy.

BACKGROUND: There is paucity of data regarding the effects of delayed reperfusion (DR) on clinical outcomes in patients with incomplete reperfusion following mechanical thrombectomy. We hypothesized that DR has a strong association with clinical outcome in patients with incomplete reperfusion after mechanical thrombectomy (expanded Thrombolysis in Cerebral Infarction, 2a-2c). METHODS: Single-institution's stroke registry retrospective analysis of patients admitted from February 2015 to December 2020. DR was defined as the absence of any perfusion delay on ≈24-hour contrast-enhanced follow-up perfusion imaging, whereas persistent perfusion deficit denotes a perfusion delay corresponding to the catheter angiographic deficit directly after the intervention. The association of perfusion outcome (DR versus persistent perfusion deficit) with the occurrence of new infarcts and 90-day functional independence (modified Rankin Scale score 0-2) was evaluated using logistic regression analyses. Comparison of predictive accuracy was evaluated by calculating area under the curve for models with and without perfusion outcome. RESULTS: In 566 patients (mean age 74, 49.6% female), new infarcts in the incomplete reperfusion areas were less common in DR versus persistent perfusion deficit patients (small punctiform: 17.1% versus 25%, large confluent: 7.9% versus 63.2%; P=0.001). After adjustment for confounders, DR was a strong predictor of functional independence (adjusted odds ratio, 2.37 [95% CI 1.34-4.23]). There was a significant improvement in predictive accuracy of functional independence when perfusion outcome was added to expanded Thrombolysis in Cerebral Infarction alone (area under the curve 0.57 versus 0.62, P=0.01). CONCLUSIONS: Occurrence of DR is closely associated with tissue outcome and functional independence. DR may be an independent prognostic parameter, suggesting it as a potential outcome surrogate for medical rescue therapies.

Aspiration Versus Stent Retriever Thrombectomy for Distal, Medium Vessel Occlusion Stroke in the Posterior Circulation: A Subanalysis of the TOPMOST Study.

BACKGROUND: The optimal endovascular strategy for reperfusing distal medium-vessel occlusions (DMVO) remains unknown. This study evaluates angiographic and clinical outcomes of thrombectomy strategies in DMVO stroke of the posterior circulation. METHODS: TOPMOST (Treatment for Primary Medium Vessel Occlusion Stroke) is an international, retrospective, multicenter, observational registry of patients treated for DMVO between January 2014 and June 2020. This study analyzed endovascularly treated isolated primary DMVO of the posterior cerebral artery in the P2 and P3 segment. Technical feasibility was evaluated with the first-pass effect defined as a modified Thrombolysis in Cerebral Infarction Scale score of 3. Rates of early neurological improvement and functional modified Rankin Scale scores at 90 days were compared. Safety was assessed by the occurrence of symptomatic intracranial hemorrhage and intervention-related serious adverse events. RESULTS: A total of 141 patients met the inclusion criteria and were treated endovascularly for primary isolated DMVO in the P2 (84.4%, 119) or P3 segment (15.6%, 22) of the posterior cerebral artery. The median age was 75 (IQR, 62-81), and 45.4% (64) were female. The initial reperfusion strategy was aspiration only in 29% (41) and stent retriever in 71% (100), both achieving similar first-pass effect rates of 53.7% (22) and 44% (44; P=0.297), respectively. There were no significant differences in early neurological improvement (aspiration: 64.7% versus stent retriever: 52.2%; P=0.933) and modified Rankin Scale rates (modified Rankin Scale score 0-1, aspiration: 60.5% versus stent retriever 68.6%; P=0.4). In multivariable logistic regression analysis, the time from groin puncture to recanalization was associated with the first-pass effect (adjusted odds ratio, 0.97 [95% CI, 0.95-0.99]; P<0.001) that in turn was associated with early neurological improvement (aOR, 3.27 [95% CI, 1.16-9.21]; P<0.025). Symptomatic intracranial hemorrhage occurred in 2.8% (4) of all cases. CONCLUSIONS: Both first-pass aspiration and stent retriever thrombectomy for primary isolated posterior circulation DMVO seem to be safe and technically feasible leading to similar favorable rates of angiographic and clinical outcome.

Dural arteriovenous fistulas in cerebral venous thrombosis: Data from the International Cerebral Venous Thrombosis Consortium: Data from the International Cerebral Venous Thrombosis Consortium.

BACKGROUND AND PURPOSE: To explore the prevalence, risk factors, time correlation, characteristics and clinical outcome of dural arteriovenous fistulas (dAVFs) in a cerebral venous thrombosis (CVT) population. METHODS: We included patients from the International CVT Consortium registries. Diagnosis of dAVF was confirmed centrally. We assessed the prevalence and risk factors for dAVF among consecutive CVT patients and investigated its impact on clinical outcome using logistic regression analysis. We defined poor outcome as modified Rankin Scale score 3-6 at last follow-up. RESULTS: dAVF was confirmed in 29/1218 (2.4%) consecutive CVT patients. The median (interquartile range [IQR]) follow-up time was 8 (5-23) months. Patients with dAVF were older (median [IQR] 53 [44-61] vs. 41 [29-53] years; p < 0.001), more frequently male (69% vs. 33%; p < 0.001), more often had chronic clinical CVT onset (>30 days: 39% vs. 7%; p < 0.001) and sigmoid sinus thrombosis (86% vs. 51%; p < 0.001), and less frequently had parenchymal lesions (31% vs. 55%; p = 0.013) at baseline imaging. Clinical outcome at last follow-up did not differ between patients with and without dAVF. Additionally, five patients were confirmed with dAVF from non-consecutive CVT cohorts. Among all patients with CVT and dAVF, 17/34 (50%) had multiple fistulas and 23/34 (68%) had cortical venous drainage. Of 34 patients with dAVF with 36 separate CVT events, 3/36 fistulas (8%) were diagnosed prior to, 20/36 (56%) simultaneously and 13/36 after (36%, median 115 [IQR 38-337] days) diagnosis of CVT. CONCLUSIONS: Dural arteriovenous fistulas occur in at least 2% of CVT patients and are associated with chronic CVT onset, older age and male sex. Most CVT-related dAVFs are detected simultaneously or subsequently to diagnosis of CVT.

Development of a Score for Prediction of Occult Malignancy in Stroke Patients (Occult-5 Score).

BACKGROUND AND PURPOSE: Malignancy associated acute ischemic stroke (AIS) requires specific diagnostic work-up, treatment and prevention to improve outcome. This study aimed to develop a biomarker-based score for prediction of occult malignancy in AIS patients. METHODS: Single-center cross-sectional study including consecutive AIS patients treated between July 2017 and November 2018. Patients with active malignancy at presentation, or diagnosed within 1 year thereafter and patients free of malignancy, were included and malignancy associated biomarkers were assessed. LASSO analyses of logistic regression were performed to determine biomarkers predictive of active malignancy. Predictors were derived from a predictive model for active malignancy. A comparison between known and unknown (=occult) malignancies when the index stroke occurred was used to eliminate variables not associated with occult malignancy. A predictive score (OCCULT-5 score) for occult malignancy was developed based on the remaining variables. RESULTS: From 1001 AIS patients, 61 (6%) presented an active malignancy. Thirty-nine (64%) were known and 22 (36%) occult. Five variables were included in the final OCCULT-5 score: age ≥ 77 years, embolic stroke of undetermined source, multi-territorial infarcts, D-dimer levels ≥ 820 µ/gL, and female sex. A score of ≥ 3 predicted an underlying occult malignancy with a sensitivity of 64%, specificity of 73%, positive likelihood ratio of 2.35 and a negative likelihood ratio of 0.50. CONCLUSIONS: The OCCULT-5 score might be useful to identify patients with occult malignancy. It may thus contribute to a more effective and timely treatment and thus lead to a positive impact on overall outcome.

Treatment and Outcome in Stroke Patients With Acute M2 Occlusion and Minor Neurological Deficits.

BACKGROUND AND PURPOSE: Treatment in stroke patients with M2 segment occlusion of the middle cerebral artery presenting with mild neurological deficits is a matter of debate. The main purpose was to compare the outcome in patients with a minor stroke and a M2 occlusion. METHODS: Consecutive intravenous thrombolysis (IVT) eligible patients admitted to the Bernese stroke center between January 2005 and January 2020 with acute occlusion of the M2 segment and National Institutes of Health Stroke Scale score ≤5 were included. Outcome was compared between IVT only versus endovascular therapy (EVT) including intra-arterial thrombolysis and mechanical thrombectomy (MT; ±IVT) and between IVT only versus MT only. RESULTS: Among 169 patients (38.5% women, median age 70.2 years), 84 (49.7%) received IVT only and 85 (50.3%) EVT (±IVT), the latter including 39 (45.9%) treated with MT only. Groups were similar in sex, age, vascular risk factors, event cause, or preevent independency. Compared with IVT only, there was no difference in favorable outcome (modified Rankin Scale score, 0-2) for EVT (adjusted odds ratio, 0.96; adjusted P=0.935) or for MT only (adjusted odds ratio, 1.12; adjusted P=0.547) groups. Considering only patients treated after 2015, there was a significantly better 3-month modified Rankin Scale shift (adjusted P=0.032) in the EVT compared with the IVT only group. CONCLUSIONS: Our study demonstrates similar effectiveness of IVT only versus EVT (±IVT), and of IVT only versus MT only in patients with peripheral middle cerebral artery occlusions and minor neurological deficits and indicates a possible benefit of EVT considering only patients treated after 2015. There is an unmet need for randomized controlled trials in this stroke field, including imaging parameters, and more sophisticated evaluation of National Institutes of Health Stroke Scale score subitems, neurocognition, and quality of life neglected by the standard outcome scales such as modified Rankin Scale and National Institutes of Health Stroke Scale score.

Bridging May Increase the Risk of Symptomatic Intracranial Hemorrhage in Thrombectomy Patients With Low Alberta Stroke Program Early Computed Tomography Score.

BACKGROUND AND PURPOSE: Whether intravenous thrombolysis (IVT) increases the risk for symptomatic intracranial hemorrhage (sICH) in patients treated with mechanical thrombectomy (MT) is a matter of debate. Purpose of this study was to evaluate the extent of early ischemia as a possible factor influencing the risk for sICH after IVT+MT versus direct MT. METHODS: An explorative analysis of the BEYOND-SWIFT (Bernese-European Registry for Ischemic Stroke Patients Treated Outside Current Guidelines With Neurothrombectomy Devices Using the SOLITAIRE FR With the Intention for Thrombectomy) multicenter cohort was performed. We hypothesized that the sICH risk between IVT+MT versus direct MT differs across the strata of Alberta Stroke Program Early CT Scores (ASPECTS). For this purpose, all patients with ICA, M1, and M2 vessel occlusions and available noncontrast computed tomography or diffusion-weighed imaging ASPECTS (n=2002) were analyzed. We used logistic regression analysis in subgroups, as well as interaction terms, to address the risk of sICH in IVT+MT versus direct MT patients across the ASPECTS strata. RESULTS: In 2002 patients (median age, 73.7 years; 50.7% women; median National Institutes of Health Stroke Scale score, 16), the overall rate of sICH was 6.5% (95% CI, 5.5%-7.7%). Risk of sICH differed across ASPECTS groups (9-10: 6.3%; 6-8: 5.6% and ≤5 9.8%; P=0.042). With decreasing ASPECTS, the risks of sICH in the IVT+MT versus the direct MT group increased from adjusted odds ratio of 0.61 ([95% CI, 0.24-1.60] ASPECTS 9-10), to 1.72 ([95% CI, 0.69-4.24] ASPECTS 6-8) and 6.31 ([95% CI, 1.87-21.29] ASPECTS ≤5), yielding a positive interaction term (1.91 [95% CI, 1.01-3.63]). Sensitivity analyses regarding diffusion-weighed imaging versus noncontrast computed tomography ASPECTS did not alter the primary observations. CONCLUSIONS: The extent of early ischemia may influence relative risks of sICH in IVT+MT versus direct MT patients, with an excess sICH risk in IVT+MT patients with low ASPECTS. If confirmed in post hoc analyses of randomized controlled trial data, IVT may be administered more carefully in patients with low ASPECTS eligible for and with direct access to MT.

Effect of Pre- and In-Hospital Delay on Reperfusion in Acute Ischemic Stroke Mechanical Thrombectomy.

BACKGROUND AND PURPOSE: Post hoc analyses of randomized controlled clinical trials evaluating mechanical thrombectomy have suggested that admission-to-groin-puncture (ATG) delays are associated with reduced reperfusion rates. Purpose of this analysis was to validate this association in a real-world cohort and to find associated factors and confounders for prolonged ATG intervals. METHODS: Patients included into the BEYOND-SWIFT cohort (Bernese-European Registry for Ischemic Stroke Patients Treated Outside Current Guidelines With Neurothrombectomy Devices Using the Solitaire FR With the Intention for Thrombectomy; https://www.clinicaltrials.gov; Unique identifier: NCT03496064) were analyzed (n=2386). Association between baseline characteristics and ATG was evaluated using mixed linear regression analysis. The effect of increasing symptom-onset-to-admission and ATG intervals on successful reperfusion (defined as Thrombolysis in Cerebral Infarction [TICI] 2b-3) was evaluated using logistic regression analysis adjusting for potential confounders. RESULTS: Median ATG was 73 minutes. Prolonged ATG intervals were associated with the use of magnetic resonance imaging (+19.1 [95% CI, +9.1 to +29.1] minutes), general anesthesia (+12.1 [95% CI, +3.7 to +20.4] minutes), and borderline indication criteria, such as lower National Institutes of Health Stroke Scale, late presentations, or not meeting top-tier early time window eligibility criteria (+13.8 [95% CI, +6.1 to +21.6] minutes). There was a 13% relative odds reduction for TICI 2b-3 (adjusted odds ratio [aOR], 0.87 [95% CI, 0.79-0.96]) and TICI 2c/3 (aOR, 0.87 [95% CI, 0.79-0.95]) per hour ATG delay, while the reduction of TICI 2b-3 per hour increase symptom-onset-to-admission was minor (aOR, 0.97 [95% CI, 0.94-0.99]) and inconsistent regarding TICI 2c/3 (aOR, 0.99 [95% CI, 0.97-1.02]). After adjusting for identified factors associated with prolonged ATG intervals, the association of ATG delay and lower rates of TICI 2b-3 remained tangible (aOR, 0.87 [95% CI, 0.76-0.99]). CONCLUSIONS: There is a great potential to reduce ATG, and potential targets for improvement can be deduced from observational data. The association between in-hospital delay and reduced reperfusion rates is evident in real-world clinical data, underscoring the need to optimize in-hospital workflows. Given the only minor association between symptom-onset-to-admission intervals and reperfusion rates, the causal relationship of this association warrants further research. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03496064.

Mechanical Cavity Creation with Curettage and Vacuum Suction (Q-VAC) in Lytic Vertebral Body Lesions with Posterior Wall Dehiscence and Epidural Mass before Cement Augmentation.

Background and Objectives: We describe a novel technique for percutaneous tumor debulking and cavity creation in patients with extensive lytic lesions of the vertebral body including posterior wall dehiscence prior to vertebral augmentation (VA) procedures. The mechanical cavity is created with a combination of curettage and vacuum suction (Q-VAC). Balloon kyphoplasty and vertebral body stenting are used to treat neoplastic vertebral lesions and might reduce the rate of cement leakage, especially in presence of posterior wall dehiscence. However, these techniques could theoretically lead to increased intravertebral pressure during balloon inflation with possible mobilization of soft tissue tumor through the posterior wall, aggravation of spinal stenosis, and resultant complications. Creation of a void or cavity prior to balloon expansion and/or cement injection would potentially reduce these risks. Materials and Methods: A curette is coaxially inserted in the vertebral body via transpedicular access trocars. The intravertebral neoplastic soft tissue is fragmented by multiple rotational and translational movements. Subsequently, vacuum aspiration is applied via one of two 10 G cannulas that had been introduced directly into the fragmented lesion, while saline is passively flushed via the contralateral cannula, with lavage of the fragmented solid and fluid-necrotic tumor parts. Results: We applied the Q-VAC technique to 35 cases of thoracic and lumbar extreme osteolysis with epidural mass before vertebral body stenting (VBS) cement augmentation. We observed extravertebral cement leakage on postoperative CT in 34% of cases, but with no clinical consequences. No patients experienced periprocedural respiratory problems or new or worsening neurological deficit. Conclusion: The Q-VAC technique, combining mechanical curettage and vacuum suction, is a safe, inexpensive, and reliable method for percutaneous intravertebral tumor debulking and cavitation prior to VA. We propose the Q-VAC technique for cases with extensive neoplastic osteolysis, especially if cortical boundaries of the posterior wall are dehiscent and an epidural soft tissue mass is present.

Cryptogenic Cerebrospinal Fluid Leaks in Spontaneous Intracranial Hypotension: Role of Dynamic CT Myelography.

Purpose To propose a modified dynamic CT myelographic technique to locate cerebrospinal fluid (CSF) leaks, also known as cryptogenic leaks, in patients with spontaneous intracranial hypotension (SIH) in whom previous imaging did not show the dural breach. Materials and Methods This retrospective analysis included 74 consecutive patients with SIH and a myelographically proven CSF leak who were evaluated between February 2013 and October 2017. In 14 patients, dynamic CT myelography in the prone or lateral position showed the exact leakage point after unsuccessful previous imaging. During image analysis, the first time point showing extrathecal contrast material was defined as the site of dural breach point. Results Mean population age was 44 years (range, 25-65 years [nine women; mean age, 44 years; age range, 25-65 years] [five men; mean age, 46 years; age range, 29-61 years]). All patients had previously undergone spine MRI, conventional dynamic myelography, and CT myelography. Subsequent dynamic CT myelography covered a mean range of seven vertebral levels. The leak was caused by a calcified microspur in 10 patients and by a dural tear at the axilla of a spinal nerve root in the remaining four. The mean volume CT dose index of dynamic CT myelography was 107 mGy (range, 12-246 mGy), and the mean dose-length product was 1347 mGy·cm (range, 550-3750 mGy·cm). Conclusion Dynamic CT myelography is a valuable adjunctive tool with which to identify the precise location of a dural tear when other examinations are unsuccessful. © RSNA, 2018 See also the editorial by Dillon in this issue.

Intravenous Iodinated Contrast Agents Amplify DNA Radiation Damage at CT.

PURPOSE: To determine the effect of the use of iodinated contrast agents on the formation of DNA double-strand breaks during chest computed tomography (CT). MATERIALS AND METHODS: This study was approved by the institutional review board, and written informed consent was obtained from all patients. This single-center study was performed at a university hospital. A total of 179 patients underwent contrast material-enhanced CT, and 66 patients underwent unenhanced CT. Blood samples were taken from these patients prior to and immediately after CT. In these blood samples, the average number of phosphorylated histone H2AX (γH2AX) foci per lymphocyte was determined with fluorescence microscopy. Significant differences between the number of foci that developed in both the presence and the absence of the contrast agent were tested by using an independent sample t test. RESULTS: γH2AX foci levels were increased in both groups after CT. Patients who underwent contrast-enhanced CT had an increased amount of DNA radiation damage (mean increase ± standard error of the mean, 0.056 foci per cell ± 0.009). This increase was 107% ± 19 higher than that in patients who underwent unenhanced CT (mean increase, 0.027 foci per cell ± 0.014). CONCLUSION: The application of iodinated contrast agents during diagnostic x-ray procedures, such as chest CT, leads to a clear increase in the level of radiation-induced DNA damage as assessed with γH2AX foci formation.

Successful Thrombectomy of the Posterior Cerebral Artery P2 Segment in a 61-Year-Old Man with Acute Ischaemic Stroke: A Case Report.

BACKGROUND Acute ischemic stroke in the posterior cerebral artery (PCA) territory can lead to persistent disabling deficits. The PCA is divided into 4 segments. The P2 segment begins at the posterior communicating artery and curves around the midbrain and above the tentorium cerebelli. This report is of a 61-year-old man with acute ischemic stroke involving the left hippocampus treated with direct thrombectomy of the P2 segment of the PCA. CASE REPORT A 61-year-old white man presented with transient amnesia, aphasia, right-sided hemianopia, dizziness, and persistent acute memory deficits. Magnetic resonance imaging (MRI) showed a left hippocampal acute ischemic stroke with left PCA occlusion in the P2 segment. Despite a low National Institutes of Health Stroke Scale (NIHSS) score and the already-formed lesion in the hippocampus, successful stent retriever thrombectomy was performed due to a considerable perfusion-diffusion mismatch and a persistent potentially disabling neurocognitive deficit. Due to partial thrombus dislocation, occlusion of the common origin of the right posterior inferior cerebellar artery (PICA) and anterior inferior cerebellar artery (AICA) occurred and was immediately treated by thrombectomy to prevent severe cerebellar infarction. His clinical symptoms completely resolved and a neuropsychological exam showed no residual deficits. CONCLUSIONS Thrombectomy of the P2 segment of the PCA is feasible and can be considered to treat patients with acute occlusion at risk for persistent disabling deficits, based on clinical estimation of the impact of such deficits and the presence of potentially salvageable brain tissue. Potential procedural complications should be sought out and immediately treated, if technically feasible.

Research productivity on spontaneous intracranial hypotension: A bibliometric analysis.

Introduction: Spontaneous intracranial hypotension (SIH) is an important cause of devastating headaches and caused by CSF-leaks in the spine. Research question: The aim of this analysis was to gain an overview of the progress of research on SIH over time. The global publication landscape relating to SIH was analyzed and comparisons between regions were made. Material and methods: A bibliometric analysis was performed by searching for research articles on SIH in PubMed published between 1983 and 2022. Countries responsible for the publications were ranked by the sum of citations. An average annual growth rate was calculated and the density of SIH publications per 100 000 physicians was determined. Results: We identified 974 articles. In 1983 only one SIH patient was reported; in 2021 the number of patients had increased to 4230. The average annual growth rate of SIH publications during this period was 12.7%. The most common publication type were case reports (n = 570). The most common medical specialty of the first author was neurology (n = 251) followed by neurosurgery (n = 250) and radiology (n = 191). Although most publications originated from the United States of America (USA), South Korea had the highest density of SIH investigators (37.86 publications per 100 000 medical doctors). The most cited paper (296 citations) was published in 2006 in JAMA (USA). Discussion and conclusion: Research on SIH has increased exponentially over the past four decades. The international community of SIH researchers is growing, and with it the opportunities for global networks involved in research, treatment, and patient education.

Microsurgical Repair of Ventral Cerebrospinal Fluid Leaks in Spontaneous Intracranial Hypotension: Efficacy and Safety of Patch-Sealing Versus Suturing.

BACKGROUND AND OBJECTIVES: In patients with spontaneous intracranial hypotension (SIH), microsurgical repair is recommended in Type 1 (ventral) dural leaks, when conservative measures fail. However, there is lacking consensus on the optimal surgical technique for permanent and safe closure of ventral leaks. METHODS: We performed a retrospective analysis of surgically treated SIH patients with Type 1 leaks at our institution between 2013 and 2023. Patients were analyzed according to the type of surgical technique: (1) Microsurgical suture vs (2) extradural and intradural patching (sealing technique). End points were resolution of spinal longitudinal epidural cerebrospinal fluid collection (SLEC), change in brain SIH-Score (Bern-Score), headache resolution after 3 months, surgery time, complications, and reoperation rates. RESULTS: In total, 85 (66% women) patients with consecutive SIH (mean age 47 ± 11 years) underwent transdural microsurgical repair. The leak was sutured in 53 (62%) patients (suture group) and patch-sealed in 32 (38%) patients (sealing group). We found no significant difference in the rates of residual SLEC and resolution of headache between suture and sealing groups (13% vs 22%, P = .238 and 89% vs 94%, P = .508). No changes were found in the postoperative Bern-Score between suture and sealing groups (1.4 [±1.6] vs 1.7 [±2.1] P = 1). Mean surgery time was significantly shorter in the sealing group than in the suture group (139 ± 48 vs 169 ± 51 minutes; P = .007). Ten patients of the suture and 3 of the sealing group had a complication (23% vs 9%, P = .212), whereas 6 patients of the suture and 2 patients of the sealing group required reoperation (11% vs 6%, P = .438). CONCLUSION: Microsurgical suturing and patch-sealing of ventral dural leaks in patients with SIH are equally effective. Sealing alone is a significantly faster technique, requiring less spinal cord manipulation and may therefore minimize the risk of surgical complications.

Connecting the DOTs: a novel imaging sign on flat-panel detector CT indicating distal vessel occlusions after thrombectomy.

BACKGROUND: Immediate non-contrast post-interventional flat-panel detector CT (FPDCT) has been suggested as an imaging tool to assess complications after endovascular therapy (EVT). We systematically investigated a new imaging finding of focal hyperdensities correlating with remaining distal vessel occlusion after EVT. METHODS: A single-center retrospective analysis was conducted for all acute ischemic stroke patients admitted between July 2020 and December 2022 who underwent EVT and immediate post-interventional FPDCT. A blinded core lab performed reperfusion grading on post-interventional digital subtraction angiography (DSA) images and evaluated focal hyperdensities on FPDCT (here called the distal occlusion tracker (DOT) sign). DOT sign was defined as a tubular or punctiform, vessel confined, hyperdense signal within the initial occlusion target territory. We assessed sensitivity and specificity of the DOT sign when compared with DSA findings. RESULTS: The median age of the cohort (n=215) was 74 years (IQR 63-82) and 58.6% were male. The DOT sign was positive in half of the cohort (51%, 110/215). The DOT sign had high specificity (85%, 95% CI 72% to 93%), but only moderate sensitivity (63%, 95% CI 55% to 70%) for detection of residual vessel occlusions. In comparison to the core lab, operators overestimated complete reperfusion in a quarter of the entire cohort (25%, 53/215). In more than half of these cases (53%, 28/53) there was a positive DOT sign, which could have mitigated this overestimation. CONCLUSION: The DOT sign appears to be a frequent finding on immediate post-interventional FPDCT. It correlates strongly with incomplete reperfusion and indicates residual distal vessel occlusions. In the future, it may be used to complement grading of reperfusion success and may help mitigating overestimation of reperfusion in the acute setting.

Flat-panel Detector Perfusion Imaging and Conventional Multidetector Perfusion Imaging in Patients with Acute Ischemic Stroke : A Comparative Study.

PURPOSE: Flat-panel detector computed tomography (FDCT) is increasingly used in (neuro)interventional angiography suites. This study aimed to compare FDCT perfusion (FDCTP) with conventional multidetector computed tomography perfusion (MDCTP) in patients with acute ischemic stroke. METHODS: In this study, 19 patients with large vessel occlusion in the anterior circulation who had undergone mechanical thrombectomy, baseline MDCTP and pre-interventional FDCTP were included. Hypoperfused tissue volumes were manually segmented on time to maximum (Tmax) and time to peak (TTP) maps based on the maximum visible extent. Absolute and relative thresholds were applied to the maximum visible extent on Tmax and relative cerebral blood flow (rCBF) maps to delineate penumbra volumes and volumes with a high likelihood of irreversible infarcted tissue ("core"). Standard comparative metrics were used to evaluate the performance of FDCTP. RESULTS: Strong correlations and robust agreement were found between manually segmented volumes on MDCTP and FDCTP Tmax maps (r = 0.85, 95% CI 0.65-0.94, p < 0.001; ICC = 0.85, 95% CI 0.69-0.94) and TTP maps (r = 0.91, 95% CI 0.78-0.97, p < 0.001; ICC = 0.90, 95% CI 0.78-0.96); however, direct quantitative comparisons using thresholding showed lower correlations and weaker agreement (MDCTP versus FDCTP Tmax 6 s: r = 0.35, 95% CI -0.13-0.69, p = 0.15; ICC = 0.32, 95% CI 0.07-0.75). Normalization techniques improved results for Tmax maps (r = 0.78, 95% CI 0.50-0.91, p < 0.001; ICC = 0.77, 95% CI 0.55-0.91). Bland-Altman analyses indicated a slight systematic underestimation of FDCTP Tmax maximum visible extent volumes and slight overestimation of FDCTP TTP maximum visible extent volumes compared to MDCTP. CONCLUSION: FDCTP and MDCTP provide qualitatively comparable volumetric results on Tmax and TTP maps; however, direct quantitative measurements of infarct core and hypoperfused tissue volumes showed lower correlations and agreement.

Basilar Artery Perforator Aneurysms - The Phantom Menace of the Intracranial Universe.

Cerebral perforators are end-arteries that vascularize specific deep territories in the cerebral hemispheres and brainstem. Due to improved imaging quality, these aneurysms are increasingly diagnosed in clinical routine. High resolution 3D angiographic images are mandatory and in some occasions fusion images might be helpful to detect these aneurysms. Basilar artery perforator aneurysms (or BAPAs) are one of the most common subtypes of perforator aneurysms and might cause subarachnoid hemorrhage along the brainstem (perimesencephalic hemorrhage). Due to the limited evidence, the management of BAPAs may pose a challenge in clinical routine. While some aneurysms can be managed conservatively, a few might require treatment to prevent rebleeding. We present the cases of two patients with BAPAs managed at our center in order to increase the awareness on these potentially underdiagnosed aneurysms.