MEDISCHE BEELDVORMING

CENTRUM MEDISCHE BEELDVORMING

ARTIKELS

ABSTRACT 1

Delayed post-anoxic white matter injury in an infant.

Degrieck B, Dutoit J, Herregods N Journal of the Belgian Society of Radiology, 2020, 104(1), 31

ABSTRACT Case report teaching point: White matter reversal on diffusion-weighted magnetic resonance imaging is indicative of delayed post-anoxic encephalopathy. This manifests sooner in young infants than in adults.

ABSTRACT 2

Very late leptomeningeal collaterals-potential new way to subdivide modified thrombolysis in cerebral ischemia (mTICI) 2B.

Yeo L, Cervo A, Gopinathan A, Andersson T, et al. Clinical Neuroradiology, 2020, 30(1), 77-83

INTRODUCTION Studies have shown that the modified thrombolysis in cerebral ischemia (mTICI) 2B score is associated with better functional outcome; however, 50-99% reperfusion is a large range and there may be factors which can differentiate this further. The effects of very late leptomeningeal collaterals (VLLC) on mTICI-2B patients were studied.

MATERIALS/METHODS A prospectively collected registry of anterior circulation AIS patients treated with the EmboTrap revascularization device from 2013 to 2016 was evaluated. Imaging parameters and timings, including the mTICI score were verified by an external core laboratory blinded to the clinical data. The final angiogram was examined for the appearance of VLLC in predicting 3-month outcomes including excellent functional outcomes, defined as modified Rankin scale (mRS) 0-1, bleeding risk and mortality.

RESULTS A total of 177 consecutive anterior circulation stroke patients were included in the analysis. Of these 94 (53.1%) achieved only mTICI-2B reperfusion, 16/94 (17.0%) patients achieved excellent functional outcomes at 3 months and 26 (27.7%) had hyperdensity on follow-up computed tomography (CT). On univariate analysis, the presence of VLLC was inversely associated with excellent functional outcomes at 3 months and positively associated with mortality in patients with mTICI-2B reperfusion. On multivariate analysis VLLC was inversely associated with excellent outcomes (odds ratio 0.075, 95% confidence interval 0.007-0.765, P = 0.029) but not associated with mortality.

CONCLUSION The mTICI-2B grade may be further refined by secondary radiological markers. The VLLC sign is associated with the loss of excellent functional outcomes at 3 months. It is a simple sign to discriminate mTICI-2B into different grades but should be verified in larger populations from other centers.

ABSTRACT 3

Structural analysis of ischemic stroke thrombi: histolo- gical indications for therapy resistance.

Staessens S, Denorme F, François O, Andersson T, et al. Haematologica, 2020, 105(2), 498-507

ABSTRACT Ischemic stroke is caused by a thromboembolic occlusion of cerebral arteries. Treatment is focused on fast and efficient removal of the occluding thrombus, either via intravenous thrombolysis or via endovascular thrombectomy. Recanalization, however, is not always successful and factors contributing to failure are not completely understood. Although the occluding thrombus is the primary target of acute treatment, little is known about its internal organization and composition.

The aim of this study, therefore, was to better understand the internal organization of ischemic stroke thrombi on a molecular and cellular level.

A total of 188 thrombi were collected from endovascularly treated ischemic stroke patients and analyzed histologically for fibrin, red blood cells (RBC), von Willebrand factor (vWF), platelets, leukocytes and DNA, using bright field and fluorescence microscopy.

Our results show that stroke thrombi are composed of two main types of areas: RBC-rich areas and platelet-rich areas. RBC-rich areas have limited complexity as they consist of RBC that are entangled in a meshwork of thin fibrin. In contrast, platelet-rich areas are characterized by dense fibrin structures aligned with vWF and abundant amounts of leukocytes and DNA that accumulate around and in these platelet-rich areas. These findings are important to

better understand why platelet-rich thrombi are resistant to thrombolysis and difficult to retrieve via thrombectomy, and can guide further improvements of acute ischemic stroke therapy.

ABSTRACT 4

ANCD thrombectomy device: in vitro evaluation.

Sanchez S, Cortiñas I, Villanova H, Andersson T, et al. Journal of Neurointerventional Surgery, 2020, 12(1), 77-81

INTRODUCTION Endovascular treatment of stroke, although highly effective, may fail to reach complete recanalization in around 20% of cases. The Advanced Thrombectomy System (ANCD) is a novel stroke thrombectomy device designed to reduce clot fragmentation and facilitate retrieval by inducing local flow arrest and allowing distal aspiration in combination with a stent retriever. We aimed to assess the preclinical efficacy of ANCD.

MATERIALS/METHODS Soft red blood cell (RBC)-rich (n=20/group) and sticky fibrin-rich (n=30/group) clots were used to create middle cerebral artery (MCA) occlusions in two vascular phantoms. Three different treatment strategies were tested: (1) balloon guide catheter + Solitaire (BGC+SR); (2) distal access catheter + SR (DAC+SR); and (3) ANCD+SR, until complete recanalization was achieved or to a maximum of three passes. The recanalization rate was determined after each pass.

RESULTS After one pass, ANCD+SR resulted in an increased recanalization rate (94%) for all clots together compared with BGC+SR (66%; p<0.01) or DAC+SR (80%; p=0.04). After the final pass the recanalization rate increased in all three groups but remained higher with ANCD+SR (100%) than with BGC+SR (74%; p<0.01) or DAC+SR (90%; p=0.02). The mean number of passes was lower with ANCD+SR (1.06) than with BGC+SR (1.46) or DAC+SR (1.25) (p=0.01). A logistic regression model adjusted for treatment arm, clot type, and model used showed that both RBC-rich clots (OR 8.1, 95% CI 1.6 to 13.5) and ANCD+SR (OR 3.9, 95% CI 1.01 to 15.8) were independent predictors of first-pass recanalization. CONCLUSION In in vitro three-dimensional models replicating MCA-M1 occlusion, ANCD+SR showed significantly better recanalization rates in fewer passes than other commonly used combinations of devices.

ABSTRACT 5

Preclinical evaluation of the ANCD thrombectomy device: safety and efficacy in a swine clot model.

Sanchez S, Bailey L, Ducore R, Andersson T, et al. Journal of Neurointerventional Surgery, 2020, 12(10), 1008-1013

INTRODUCTION The Advanced Thrombectomy System (ANCD) provides a new funnel component designed to reduce clot fragmentation and facilitate retrieval in patients with stroke by locally restricting flow, allowing distal aspiration in combination with a stent retriever (SR).

OBJECTIVE To evaluate the preclinical efficacy and safety of the ANCD in a swine clot model.

MATERIALS/METHODS Soft and firm clots were implanted in the lingual and cervical arteries of 11 swine to obtain Thrombolysis in Cerebral Infarction (TICI) 0 blood flow. Mechanical thrombectomy was performed with either a balloon guide catheter+Solitaire 2 stent retriever (BGC+SR, n=13) or ANCD+SR (n=13). TICI flow was evaluated and successful revascularization was defined as TICI 3 (normal perfusion). To characterize safety, a total of 3 passes were performed in each vessel independent of recanalization. Tissues were explanted for histopathological analysis after 3 and 30 days, respectively.

RESULTS First pass reperfusion rates were ANCD+SR: 69% and BGC+SR: 46%. Reperfusion increased after the third pass in both groups (ANCD+SR: 100%, vs BGC+SR: 77%). Recanalization was achieved after an average of 1.4 and 1.9 passes in ANCD+SR and BGC+SR (p=0.095), respectively. Vessel injury was comparable in both groups; endothelial loss at 3 days was the most common injury seen (ANCD+SR: 1.78±1.22; BGC+SR: 2.03±1.20; p=0.73), while other histopathological markers were absent or minimal. Tissues downstream from targeted vessels also showed absence or minimal lesions across both groups.

CONCLUSION Results in a swine clot model support the high efficacy of the ANCD+SR without causing clinically significant vessel injury potentially related to the new funnel component.

ABSTRACT 6

Intracranial stenting after failed thrombectomy in patients with moderately severe stroke: a multicenter cohort study.

Meyer L, Fiehler J, Thomalla G, Andersson T, et al. Frontiers in Neurology, 2020, 11, 97

INTRODUCTION Recently, acute intracranial stenting (ICS) has gained more interest as a potential bailout strategy for large vessel occlusions (LVO) that are refractory to thrombectomy. However, there are currently no reports on ICS in patients with moderately severe stroke discussing the question if implementing a permanent stent is feasible and leads to improved recanalization after failed thrombectomy.

MATERIALS/METHODS We analyzed a large multicenter database of patients receiving ICS for anterior circulation LVO after failed thrombectomy. Inclusion criteria were defined as: Moderately severe stroke (National Institute Health Stroke Scale (NIHSS) ≤9 on admission), anterior circulation LVO, acute ICS after failed stent retriever MT. Primary endpoint was the rate of improved successful recanalization after ICS defined as a modified Thrombolysis In cerebral Infarction (mTICI) score≥2b. Favorable neurological outcome was defined as an early neurological improvement (ENI) of 4 points or reaching 0 with respect to baseline NIHSS.

RESULTS Forty-one patients met the inclusion criteria. A median of 2 retrievals were performed (IQR 1-4) prior decision-making for ICS. ICS led in 90.2% (37/41) of cases to a final mTICI≥2b with significant improvement (p < 0.001) after the last retrieval attempt. The median NIHSS decreased (p = 0.178) from 7 (IQR 3.5-8) on admission to 2.5 (IQR 0-8.25) at discharge. ENI was observed in 47.4% (18/38). sICH occurred in 4.8% (2/41). CONCLUSION ICS after failed thrombectomy appears to effectively improve recanalization rates in patients with moderately severe strokes. Thus, ICS should be considered also for patients with baseline NIHSS ≤9 if thrombectomy fails.

ABSTRACT 7

Emergency intracranial stenting in acute stroke: predictors for poor outcome and for complications.

Stracke C, Fiehler J, Meyer L, Andersson T, et al. Journal of the American Heart Association, 2020, 9(5), DOI: 10.1161/JAHA.119.012795

INTRODUCTION Stent-retriever thrombectomy is the first-line therapy in acute stroke with intracranial large vessel occlusion. In case of failure of stent-retriever thrombectomy, rescue stent angioplasty might be the only treatment option to achieve permanent recanalization. This study aims at identifying predictors for poor outcome and complications in a large, multicenter cohort receiving rescue stent angioplasty.

MATERIALS/METHODS We performed a retrospective analysis of patients with large vessel occlusion who were treated with rescue stent angioplasty after stent-retriever thrombectomy between 2012 and 2018 in 7 neurovascular centers. We defined 2 binary outcomes: (1) functional clinical outcome (good modified Rankin Scale, 0–2; and poor modified Rankin Scale, 4–6) and (2) early symptomatic intracerebral hemorrhage. Impacts of clinical, radiological, and interventional parameters on outcomewere assessed in uni- and multivariable logistic regression models.

RESULTS Two hundred ten patients were included with target vessels located within the anterior circulation (136 of 210; 64.8%) and posterior circulation (74 of 210; 35.2%). Symptomatic intracerebral hemorrhage occured in 22 patients, 86.4% (19 of 22) after anterior and 13.6% (3 of 22) after posterior circulation large vessel occlusion. Good functional outcome was observed in 44.8% (73 of 163). A higher National Institutes of Health Stroke Scale on admission (adjusted odds ratio, 1.10; P=0.002), a higher premorbid modified Rankin Scale (adjusted odds ratio, 2.02; P=0.049), and a modified Thrombolysis in Cerebral Infarction score of 0 to 2a after stenting (adjusted odds ratio, 23.24; P<0.001) were independent predictors of poor functional outcome.

CONCLUSION Use of rescue stent angioplasty can be considered for acute intracranial large vessel occlusion in cases after unsuccessful stent-retriever thrombectomy. Likelihood of symptomatic intracerebral hemorrhage is higher in anterior circulation stroke.

ABSTRACT 8

Belgian multicentre study on lumbar spine imaging: radiation dose and cost analysis: evaluation of compliance with recommendations for efficient use of medical imaging.

De Roo B, Hoste P, Stichelbaut N, Verstraete K, et al. European Journal of Radiology, 2020, Apr, DOI: 10.1016/j. ejrad.2020.108864

OBJECTIVE To assess compliance of lumbar spine imaging referrals with national imaging recommendations and to evaluate the impact of inappropriate imaging on the collective radiation dose and health insurance costs.

MATERIALS/METHODS In 2011 and 2015, 633 lumbar spine imaging referrals were evaluated across 9 Belgian hospitals. For each patient, a new clinical anamnesis and physical examination were performed. Together with the referral, this data were confronted with the national imaging recommendations. Collective radiation dose was estimated for the radiography and CT procedures. Cost analysis was based on national reimbursement fees. Statistical analysis was performed using multilevel linear and logistic regression models.

RESULTS The fraction of unjustified imaging referrals decreased from 50 % in 2011 to 41 % in 2015 (p = 0.255). The odds of a justified examination are 3.1 times higher when the referral is done by a specialist instead of a general practitioner. The highest percentage of unjustified examinations was found for CT (85 % in 2011, 81 % in 2015; p = 0.044). Seventyfive percent of the collective dose of both the 2011 and the 2015 study population was not justified. Adherence to the recommendations could result in an estimated 16 % and 5 % cost reduction for the 2011 and 2015 study samples, respectively.

CONCLUSION Between 2011 and 2015, no significant improvement was found in requesting justified lumbar spine imaging procedures, although a positive trend was observed for CT. A shift from CT to MRI is necessary to improve the appropriateness of lumbar spine imaging referrals and to reduce the collective radiation dose.

ABSTRACT 9

Case series: dual-energy CT in extra-articular manifestations of gout.

De Vulder N, Chen M, Huysse W, Verstraete K, et al. Journal of the Belgian Society of Radiology, 2020, 104(1), 27

ABSTRACT Extra-articular manifestations of gout are common. The Achilles tendon is a frequently affected site, and uric acid deposition may have harmful effects on tendon structure and function. Advanced imaging can aid in early diagnosis, follow-up of disease activity and therapy efficacy. This case series highlights the use of dual-energy CT as a tool in diagnosing gout and in detecting extra-articular manifestations.

ABSTRACT 10

Dental and skeletal imaging in forensic age estimation: disparities in current approaches and the continuing search for optimization.

De Tobel J, Ottow C, Widek T, Verstraete K, et al. Seminars in Musculoskeletal Radiology, 2020, 24(5), 510-522

ABSTRACT Medical imaging for forensic age estimation in living adolescents and young adults continues to be controversial and a subject of discussion. Because age estimation based on medical imaging is well studied, it is the current gold standard. However, large disparities exist between the centers conducting age estimation, both between and within countries. This review provides an overview of the most common approaches applied in Europe, with case examples illustrating the differences in imaging modalities, in staging of development, and in statistical processing of the age data. Additionally, the review looks toward the future because several European research groups have intensified studies on age estimation, exploring four strategies for optimization: (1) increasing sample sizes of the reference populations, (2) combining single-site information into multifactorial information, (3) avoiding ionizing radiation, and (4) conducting a fully automated analysis.

ABSTRACT 11

Magnetic resonance imaging for forensic age estimation in living children and young adults: a systematic review.

De Tobel J, Bauwens J, Parmentier G, Verstraete K, et al. Pediatric Radiology, 2020, 50, 1691-1708

ABSTRACT The use of MRI in forensic age estimation has been explored extensively during the last decade. The authors of this paper synthesized the available MRI data for forensic age estimation in living children and young adults to provide a comprehensive overview that can guide age estimation practice and future research. To do so, the authors searched MEDLINE, Embase and Web of Science, along with cited and citing articles and study registers. Two authors independently selected articles, conducted data extraction, and assessed risk of bias. They considered study populations including living subjects up to 30 years old. Fifty-five studies were included in qualitative analysis and 33 in quantitative analysis. Most studies had biases including use of relatively small European (Caucasian) populations, varying MR approaches and varying staging techniques. Therefore, it was not appropriate to pool the age distribution data.

The authors found that reproducibility of staging was remarkably lower in clavicles than in any other anatomical structure. Age estimation performance was in line with the gold standard, radiography, with mean absolute errors ranging from 0.85 years to 2.0 years. The proportion of correctly classified minors ranged from 65% to 91%. Multifactorial age estimation performed better than that based on a single anatomical site. The authors found that more multifactorial age estimation studies are necessary, together with studies testing whether the MRI data can safely be pooled. The current review results can guide future studies, help medical professionals to decide on the preferred approach for specific cases, and help judicial professionals to interpret the evidential value of age estimation results.

ABSTRACT 12

Multi-factorial age estimation: a Bayesian approach combining dental and skeletal magnetic resonance imaging.

De Tobel J, Fieuws S, Hillewig E, Verstraete K, et al. Forensic Science International, 2020, Jan, DOI: 10.1016/j. forsciint.2019.110054 OBJECTIVE To study age estimation performance of combined magnetic resonance imaging (MRI) data of all four third molars, the left wrist and both clavicles in a reference population of females and males. To study the value of adding anthropometric and sexual maturation data.

MATERIALS/METHODS Three Tesla MRI of the three anatomical sites was prospectively conducted from March 2012 to May 2017 in 14- to 26-year-old healthy Caucasian volunteers (160 females, 138 males). Development was assessed by allocating stages, anthropometric measurements were taken, and self-reported sexual maturation data were collected. All data was incorporated in a continuation-ratio model to estimate age, applying Bayes’ rule to calculate point and interval predictions. Two performance aspects were studied: (1) accuracy and uncertainty of the point prediction, and (2) diagnostic ability to discern minors from adults (≥18 years).

RESULTS Combining information from different anatomical sites decreased the mean absolute error (MAE) compared to incorporating only one site (P < 0.0001). By contrast, adding anthropometric and sexual maturation data did not further improve MAE (P = 0.11). In females, combining all three anatomical sites rendered a MAE equal to 1.41 years, a mean width of the 95% prediction intervals of 5.91 years, 93% correctly classified adults and 91% correctly classified minors. In males, the corresponding results were 1.36 years, 5.49 years, 94%, and 90%, respectively.

CONCLUSION All aspects of age estimation improve when multi-factorial MRI data of the three anatomical sites are incorporated. Anthropometric and sexual maturation data do not seem to add relevant information.

ABSTRACT 13

Staging clavicular development on MRI: pitfalls and suggestions for age estimation.

De Tobel J, Hillewig E, Van Wijk M, Verstraete K, et al. Journal of Magnetic Resonance Imaging, 2020, 51(2), 377-388

INTRODUCTION MRI of the clavicle's sternal end has been studied for age estimation. Several pitfalls have been noted, but how they affect age estimation performance remains unclear.

OBJECTIVE To further study these pitfalls and to make suggestions for a proper use of clavicle MRI for forensic age estimation. Our hypotheses were that age estimation would benefit from 1) discarding stages 1 and 4/5; 2) including advanced substages 3aa, 3ab, and 3ac; 3) taking both clavicles into account; and 4) excluding morphological variants.

MATERIALS/METHODS Population: Healthy Caucasian volunteers between 11 and 30 years old (524; 277 females, 247 males). Field Strength/ Sequence: 3T, T1-weighted gradient echo volumetric interpolated breath-hold examination (VIBE) MR-sequence.

ASSESSMENT Four observers applied the most elaborate staging technique for long bone development that has been described in the current literature (including stages, substages, and advanced substages). One of the observers repeated a random selection of the assessments in 110 participants after a 2-week interval. Furthermore, all observers documented morphological variants.

STATISTICAL TESTS Weighted kappa quantified reproducibility of staging. Bayes' rule was applied for age estimation with a continuation ratio model for the distribution of the stages. According to the hypotheses, different models were tested. Mean absolute error (MAE) differences between models were compared, as were MAEs between cases with and without morphological variants.

RESULTS Weighted kappa equaled 0.82 for intraobserver and ranged between 0.60 and 0.64 for interobserver agreement. Stages 1 and 4/5 were allocated interchangeably in 4.3% (54/1258). Age increased steadily in advanced substages of stage 3, but improvement in age estimation was not significant (right P = 0.596; left P = 0.313). The model that included both clavicles and discarded stages 1 and 4/5 yielded an MAE of 1.97 years, a root mean squared error of 2.60 years, and 69% correctly classified minors. Morphological variants rendered significantly higher MAEs (right 3.84 years, P = 0.015; left 2.93 years, P = 0.022).

CONCLUSION Our results confirmed hypotheses 3) and 4), while hypotheses 1) and 2) remain to be investigated in larger studies. ABSTRACT 14

Subsynovial epidermal inclusion cyst of the knee.

Seynaeve P, Vanrietvelde F, Verstraete K, et al. Skeletal Radiology, 2020, 49(2), 317-319

ABSTRACT We report a case of a subsynovial epidermal inclusion cyst in a 47-year-old woman with a painful spontaneous swelling of the right knee and a 2-year history of puncture and arthroscopy. Epidermal inclusion cysts are one of the most common benign subcutaneous tumours. Very rarely, they are located in an articulation and can cause an inflammatory reaction when rupture occurs. Simple surgical excision is the preferred therapy. The main goal of this case report is to include the possibility of an intra-articular epidermal inclusion cyst into the differential when imaging shows an intra-articular structure, and more so if there is a history of trauma, intra-articular puncture or arthroscopy.

ABSTRACT 15

The influence of motion artefacts on magnetic resonance imaging of the clavicles for age estimation.

De Tobel J, Van Wijk M, Alberink I, Verstraete K, et al. International Journal of Legal Medicine, 2020, 134(2), 753-768

INTRODUCTION To determine how motion affects stage allocation to the clavicle’s sternal end on MRI.

MATERIALS/METHODS Eighteen volunteers (9 females, 9 males) between 14 and 30 years old were prospectively scanned with 3-T MRI. One resting-state scan was followed by five intentional motion scans. Additionally, a control group of 72 resting-state scans were selected from previous research. Firstly, six observers allocated developmental stages to the clavicles independently. Secondly, they re-assessed the images, allocating developmental statuses (immature, mature). Finally, the resting-state scans of the 18 volunteers were assessed in consensus to decide on the “correct” stage/ status. Results were compared between groups (control, prospective resting state, prospective motion), and between staging techniques (stages/statuses).

RESULTS Inter-observer agreement was low (Krippendorff a 0.23–0.67). The proportion of correctly allocated stages (64%) was lower than correctly allocated statuses (83%). Overall, intentional motion resulted in fewer assessable images and less images of sufficient evidential value. The proportion of correctly allocated stages did not differ between resting-state (64%) and motion scans (65%), while correctly allocated statuses were more prevalent in resting-state scans (83% versus 77%). Remarkably, motion scans did not render a systematically higher or lower stage/status, compared to the consensus.

CONCLUSION Intentional motion impedes clavicle MRI for age estimation. Still, in case of obvious disturbances, the forensic expert will consider the MRI unsuitable as evidence. Thus, the development of the clavicle as such and the staging technique seem to play a more important role in allocating a faulty stage for age estimation.

ABSTRACT 16

Health economic impact of first-pass success among patients with acute ischemic stroke treated with mecha- nical thrombectomy: a United States and European perspective.

Zaidat O, Ribo M, Mattle H, Andersson T, et al. Journal of Neurointerventional Surgery, 2020, DOI: 10.1136/neurintsurg-2020-016930

INTRODUCTION First-pass effect (FPE), restoring complete or near complete reperfusion (modified Thrombolysis in Cerebral Infarction (mTICI) 2c-3) in a single pass, is an independent predictor for good functional outcomes in the endovascular treatment of acute ischemic stroke. The economic implications of achieving FPE have not been assessed.

OBJECTIVE To assess the economic impact of achieving complete or near complete reperfusion after the first pass.

MATERIALS/METHODS Post hoc analyses were conducted using ARISE II study data. The target population consisted of patients in whom mTICI 2c-3 was achieved, stratified into two groups: (1) mTICI 2c-3 achieved after the first pass (FPE group) or (2) after multiple passes (non-FPE group). Baseline characteristics, clinical outcomes, and healthcare resource use were compared between groups. Costs from peer-reviewed literature were applied to assess cost consequences from the perspectives of the United States (USA), France, Germany, Italy, Spain, Sweden, and United Kingdom (UK).

RESULTS Among patients who achieved mTICI 2c-3 (n=172), FPE was achieved in 53% (n=91). A higher proportion of patients in the FPE group reached good functional outcomes (90-day modified Rankin Scale score 0-2 80.46% vs 61.04%, p<0.01). The patients in the FPE group had a shorter mean length of stay (6.10 vs 9.48 days, p<0.01) and required only a single stent retriever, whereas 35% of patients in the non-FPE group required at least one additional device. Driven by improvement in clinical outcomes, the FPE group had lower procedural/hospitalization-related (24-33% reduction) and annual care (11-27% reduction) costs across all countries.

CONCLUSION FPE resulted in improved clinical outcomes, translating into lower healthcare resource use and lower estimated costs.

ABSTRACT 17

Mechanical thrombectomy with a novel device: initial clinical experience with the ANA thrombectomy device.

Tomasello A, Hernandez D, Pinana C, Andersson T, et al. Journal of Neuroradiology, 2020, Dec 16, DOI: 10.1016/j. neurad.2020.11.003

INTRODUCTION The ANA™ (Anaconda Biomed) thrombectomy system is a novel stroke thrombectomy device comprising a self-expanding funnel designed to reduce clot fragmentation by locally restricting flow while becoming as wide as the lodging artery. Once deployed, ANA allows distal aspiration in combination with a stentretriever (SR) to mobilize the clot into the funnel where it remains copped during extraction. We investigate safety and efficacy of ANA™ in a first-in-man study.

MATERIALS/METHODS Prospective data was collected on 35 consecutive patients treated as first line with ANA™ at a single centre. Outcome measures included per-pass reperfusion scores, symptomatic intracerebral hemorrhage (sICH), NIHSS at day 5, and mRS at 90 days.

RESULTS Median NIHSS was 12(9-18). Sites of primary occlusion were: 5 ICA, 15 M1-MCA, 15 M2-MCA. Primary performance endpoint, mTICI 2b-3 within 3 passes without rescue therapy was achieved in 91.4% (n = 32) of patients; rate of complete recanalization (mTICI 2c-3) was 65.7%. First pass complete recanalization rate was 42.9%, and median number of ANA passes 1(IQR: 1-2). In 17.1% (n = 6) rescue treatment was used; median number of rescue passes was 2(1-7), leading to a final mTICI2b-3rate of 94.3% (n = 33). There were no device related serious adverse events, and rate of sICH was 5.7% (n = 2). At 5 days median NIHSS was 1 (IQR 1-6) and 90 days mRS 0-2 was achieved in 60% of patients.

CONCLUSION In this initial clinical experience, the ANA™ device achieved a high rate of complete recanalization with a good safety profile and favourable 90 days clinical outcomes.

ABSTRACT 18

Benefit of endovascular thrombectomy for M2 middle cerebral artery occlusion in the ARISE II study.

De Havenon A, Narata A, Amelot A, Andersson T, et al. Journal of Neurointerventional Surgery, 2020, DOI: 10.1136/neurintsurg-2020-016427

INTRODUCTION The benefit of endovascular thrombectomy for acute ischemic stroke with M2 segment middle cerebral artery occlusion remains controversial, with uncertainty and paucity of data specific to this population.

OBJECTIVE To compare outcomes between M1 and M2 occlusions in the Analysis of Revascularization in Ischemic Stroke with EmboTrap (ARISE II) trial.

MATERIALS/METHODS We performed a prespecified analysis of the ARISE II trial with the primary outcome of 90-day modified Rankin Scale score of 0-2, which we termed good outcome. Secondary outcomes included reperfusion rates and major adverse events. The primary predictor was M2 occlusion, which we compared with M1 occlusion. RESULTS We included 183 patients, of whom 126 (69%) had M1 occlusion and 57 (31%) had M2 occlusion. There was no difference in the reperfusion rates or adverse events between M2 and M1 occlusions. The rate of good outcome was not different in M2 versus M1 occlusions (70.2% vs 69.7%, p=0.946). In a logistic regression model adjusted for age, sex, and baseline National Institutes of Health Stroke Scale score, M2 occlusions did not have a significantly different odds of good outcome compared with M1 occlusions (OR 0.94, 95% CI 0.47 to 1.88, p=0.87).

CONCLUSION In ARISE II, M2 occlusions achieved a 70.2% rate of good outcome at 90 days, which is above published rates for untreated M2 occlusions and superior to prior reports of M2 occlusions treated with endovascular thrombectomy. We also report similar rates of good outcome, successful reperfusion, death, and other adverse events when comparing the M1 and M2 occlusions.

ABSTRACT 19

Left ventricular systolic dysfunction is associated with poor functional outcomes after endovascular thrombectomy.

Tan B, Leow A, Lee T, Andersson T, et al. Journal of Neurointerventional Surgery, 2020, DOI: 10.1136/neurintsurg-2020-016216

INTRODUCTION Endovascular thrombectomy (ET) has transformed acute ischemic stroke (AIS) therapy in patients with large vessel occlusion (LVO). Left ventricular systolic dysfunction (LVSD) decreases global cerebral blood flow and predisposes to hypoperfusion. We evaluated the relationship between LVSD, as measured by LV ejection fraction (LVEF), and clinical outcomes in patients with anterior cerebral circulation LVO who underwent ET.

MATERIALS/METHODS This multicenter retrospective cohort study examined anterior circulation LVO AIS patients from six international stroke centers. LVSD was measured by assessment of the echocardiographic LVEF using Simpson's biplane method of discs according to international guidelines. LVSD was defined as LVEF <50%. The primary outcome was defined as a good functional outcome using a modified Rankin Scale (mRS) of 0-2 at 3 months.

RESULTS We included 440 AIS patients with LVO who underwent ET. On multivariate analyses, pre-existing diabetes mellitus (OR 2.05, 95% CI 1.24 to 3.39;p=0.005), unsuccessful reperfusion (Treatment in Cerebral Infarction (TICI) grade 0-2a) status (OR 4.21, 95% CI 2.04 to 8.66; p<0.001) and LVSD (OR 2.08, 95% CI 1.18 to 3.68; p=0.011) were independent predictors of poor functional outcomes at 3 months. On ordinal (shift) analyses, LVSD was associated with an unfavorable shift in the mRS outcomes (OR 2.32, 95% CI 1.52 to 3.53; p<0.001) after adjusting for age and ischemic heart disease.

CONCLUSION Anterior circulation LVO AIS patients with LVSD have poorer outcomes after ET, suggesting the need to consider cardiac factors for ET, the degree of monitoring and prognostication post-procedure.

ABSTRACT 20

Multicenter, retrospective analysis of endovascular treatment for acute ischemic stroke in nonagenarians.

Janssen H, Nannoni S, François O, Andersson T, et al. Journal of stroke and Cerebrovascular Diseases, 2020, 29(8), DOI: 10.1016/j.jstrokecerebrovasdis.2020.104817

INTRODUCTION With the increasing age of acute stroke patients being admitted to hospitals, more data are needed on indications, complications and outcome of endovascular treatment (EVT) in the very elderly.

MATERIALS/METHODS Retrospective observational study with data collection from Belgian, Swiss, Canadian comprehensive stroke centers and Swedish EVT National database. All patients with acute ischemic stroke were eligible if aged older than or ≥90 years and treated with EVT ± pretreatment with intravenous thrombolysis (IVT). Safety assessment comprised presence of periprocedural complications, hemorrhagic transformation or other adverse events (<7days). Efficacy and outcome measures were successful recanalization (modified Treatment In Cerebral Infarction (mTICI) score ≥2b), favorable clinical outcome (modified Rankin Score (mRS) 0-2) and 3-months mortality. RESULTS Inclusion of 112 nonagenarians (mean age 93.3 ± 2.5 years; 76.8% women; pre-mRS ≤2 in 69.4%). Pretreatment with IVT was performed in 54.7%. In 74.6% successful recanalization (mTICI ≥2b) was achieved. Favorable outcome (mRS ≤2) was seen in 16.4% and 3-months mortality was 62.3%. Multivariate logistic regression analysis showed younger age (odds ratio [OR] 2.99; 1.29-6.95; P = .011) and lower prestroke mRS (OR 13.46; 2.32-78.30; P = .004) as significant predictors for good clinical outcome at 90 days.

CONCLUSION Our observational study on EVT in nonagenarians demonstrates the need for careful patient selection. A substantial proportion of nonagenarians shows an unfavorable clinical outcome and high mortality, despite acceptable recanalization rates. A high prestroke disability (mRS) and advancing age predict an unfavorable outcome. Treatment decisions should be made on case-by-case evaluation, keeping in mind limited chances of favorable outcome and high risk of mortality.

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Histological stroke clot analysis after thrombectomy: technical aspects and recommendations.

Staessens S, Fitzgerald S, Andersson T, et al. International Journal of Stroke, 2020, 15(5), 467-476

ABSTRACT The recent advent of endovascular procedures has created the unique opportunity to collect and analyze thrombi removed from cerebral arteries, instigating a novel subfield in stroke research. Insights into thrombus characteristics and composition could play an important role in ongoing efforts to improve acute ischemic stroke therapy. An increasing number of centers are collecting stroke thrombi. This paper aims at providing guiding information on thrombus handling, procedures, and analysis in order to facilitate and standardize this emerging research field.

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Intracranial stenting after failed thrombectomy in patients with moderately severe stroke: a multicenter cohort study.

Meyer L, Fiehler J, Thomalla G, Andersson T, et al. Frontiers in Neurology, 2020, 11, 97

INTRODUCTION Recently, acute intracranial stenting (ICS) has gained more interest as a potential bailout strategy for large vessel occlusions (LVO) that are refractory to thrombectomy. However, there are currently no reports on ICS in patients with moderately severe stroke discussing the question if implementing a permanent stent is feasible and leads to improved recanalization after failed thrombectomy.

MATERIALS/METHODS We analyzed a large multicenter database of patients receiving ICS for anterior circulation LVO after failed thrombectomy. Inclusion criteria were defined as: Moderately severe stroke (National Institute Health Stroke Scale (NIHSS) ≤9 on admission), anterior circulation LVO, acute ICS after failed stent retriever MT. Primary endpoint was the rate of improved successful recanalization after ICS defined as a modified Thrombolysis In cerebral Infarction (mTICI) score≥2b. Favorable neurological outcome was defined as an early neurological improvement (ENI) of 4 points or reaching 0 with respect to baseline NIHSS.

RESULTS Forty-one patients met the inclusion criteria. A median of 2 retrievals were performed (IQR 1-4) prior decision-making for ICS. ICS led in 90.2% (37/41) of cases to a final mTICI≥2b with significant improvement (p < 0.001) after the last retrieval attempt. The median NIHSS decreased (p = 0.178) from 7 (IQR 3.5-8) on admission to 2.5 (IQR 0-8.25) at discharge. ENI was observed in 47.4% (18/38). sICH occurred in 4.8% (2/41).

CONCLUSION ICS after failed thrombectomy appears to effectively improve recanalization rates in patients with moderately severe strokes. Thus, ICS should be considered also for patients with baseline NIHSS ≤9 if thrombectomy fails.

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An oblique fibular tunnel is recommended when reconstructing the ATFL and CFL.

Michels F, Matrical, G, Guillo S, Vanrietvelde F, Stockmans F, et al. Knee Surgery, Sports Traumatology, Arthroscopy, 2020, 28(1), 124-131

INTRODUCTION A bone tunnel is often used during the reconstruction of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL).

OBJECTIVE The purpose of this study is to compare proposed directions for drilling this fibular tunnel and to assess potential tunnel length, using a 5-mm diameter tunnel and surrounding bone.

MATERIALS/METHODS Anonymous DICOM data from spiral CT-scan images of the ankle were obtained from 12 Caucasian patients: 6 females and 6 males. Virtual tunnels were generated in a 3D bone model with angles of 30, 45, 60 and 90 degrees in relation to the fibular long axis. Several measurements were performed: distance from entrance to perforation of opposing cortex, shortening of the tunnel, distance from tunnel centre to bone surface.

RESULTS A tunnel in a perpendicular direction resulted in an average possible tunnel length of 16.8 (± 2.7) mm in the female group and 20.3 (± 3.4) mm in the male group. A tunnel directed at 30 degrees offered the longest length: 30.9 (± 2.5) mm in the female group and 34.4 (± 2.9) mm in the male group. The use of a 5-mm diameter tunnel in a perpendicular direction caused important shortening of the tunnel at the entrance in some cases. The perpendicular tunnel was very near to the digital fossa while the most obliquely directed tunnels avoided this region.

CONCLUSION An oblique tunnel allows for a longer tunnel and avoids the region of the digital fossa, thereby retaining more surrounding bone. In addition, absolute values of tunnel length are given, which can be useful when considering the use of certain implants. We recommend to drill an oblique fibular tunnel when reconstructing the ATFL and CFL.

PRESENTATIES

ABSTRACT 24

Posterior circulation MT.

Andersson T

December 2020, BRAIN (Barts Research and Advanced Interventional Neuroradiology) Conference 2020, Londen - Verenigd Koninkrijk

ABSTRACT 25

Intracranial atherosclerotic disease (ICAD).

Andersson T

December 2020, BRAIN (Barts Research and Advanced Interventional Neuroradiology) Conference 2020, Londen - Verenigd Koninkrijk ABSTRACT 30

Flow diversion in intracranial aneurysms - the final solution?

Andersson T

February 2020, 9th Annual Conference of Neurological Surgeons' Society of India (NSSICON 2020), Kolkata - India

ABSTRACT 26

How to achieve first pass success in mechanical thrombectomy?

Andersson T

October 2020, Oriental Conference on Interventional Neurovascology (OCIN), Shanghai – China October 2020, Japan Neurosurgical Society Annual Congress 2020, Okayama – Japan October 2020, SLICE Worldwide Conference 2020, Montpellier – Frankrijk September 2020, 12th congress of the Minimally Invasive Neurological Therapy (ESMINT), Nice – Frankrijk

ABSTRACT 27

Different approaches to different tandem occlusions.

Andersson T

October 2020, SLICE Worldwide Conference 2020, Montpellier - Frankrijk

ABSTRACT 28

Anti-aggregation in relation to mechanical thrombectomy.

Andersson T

September 2020, Symposium on anti-thrombotic treatment in vascular diseases, Stockholm - Zweden

ABSTRACT 29

Endovascular treatment in ischemic stroke - tools of the trade yesterday, today and tomorrow.

Andersson T

February 2020, 9th Annual Conference of Neurological Surgeons' Society of India (NSSICON 2020), Kolkata - India ABSTRACT 31

Histological analysis of an almost irretrievable thrombus in AIS.

Andersson T

January 2020, ABC-WIN conference, Val D'Isère - Frankrijk

ABSTRACT 32

Flow diversion for intracranial aneurysms: the final solution?

Andersson T

February 2020, 9th Annual Conference of the Neurological Society of India, Kolkata - India

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A differential diagnosis pathway to guide genetic testing for SHH mutation.

Xu J, Seynaeve L, Vanovermeire O, van den Hauwe L, Seynaeve P March 2020, European Society of Radioloogy, EPOS, Wenen – Oostenrijk

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Combined ablation and resection (care) for colorectal liver metastasis in the era of minimal invasive surgery.

Vandeputte M, Saveyn T, Lutin B, De Meyere C, Parementier I, D'Hondt M November 2020, Belgian Surgical Week, Antwerpen – België

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Detailed histological analysis of ischemic stroke thrombi reveals a platelet-dominant thrombus composition in patients with cardioembolic etiology.

Staessens S, François O, Desender L, Dewaele T, Vanacker P, et al. November 2020, BSTH congress, Brussel – België

ABSTRACT 36

Histological analysis of a thrombectomy-resistant ischemic stroke thrombus: a case report.

Staessens S, François O, Dewaele T, Vanacker P, Andersson T, et al. November 2020, BSTH 2019 & ESO-WSO Conference 2020, Wenen - Oostenrijk