Interventional neuroradiology of stroke, still not dead

Since the National Institute of Neurological Disorders and Stroke trial,intravenous thrombolysis has been gaining wide acceptance as the modality of treatment for acute embolic stroke,with a current therapeutic window of up to 4.5 h.Both imaging[with either magnetic resonance imaging(MRI)or computed tomography(CT)]and interventional techniques(thrombolysis and/or thrombectomy)have since improved and provided us with additional imaging of the penumbra using CT or MRI and more advanced thrombolysis or thrombectomy strategies that have been embraced in many centers dealing with patients with acute cerebral ischemia.These techniques,however,have come under scrutiny due to their accrued healthcare costs and have been questioned following major recent studies.These studies basically showed that interventional techniques were not superior to the traditional intravenous thrombolysis techniques and that penumbra imaging could not determine what patients would benefit from more aggressive(i.e.,interventional)treatment.We discuss this in the light of the latest developments in both diagnostic and interventional neuroradiology and point out why further studies are needed in order to define the right choices for patients with acute stroke.Indeed,these studies were in part conducted with suboptimal patient recruitment strategies and did not always use the latest interventional techniques available today.So,while these studies may have raised some relevant questions,at the same time,definitive answers have not been given,in our opinion.

Qualitative and Quantitative Perfusion Parameters Determined by 3D Single-Shot GRASE ASL MR Imaging

Rationale and Objectives: A particular arterial spin (ASL) labeling technique, called 3D-single-shot GRASE ASL is discussed with respect to the ability and limits of quantifying perfusion parameters. Materials and Methods: The technique enables the acquisition of perfusion weighted signal at multiple delay times (TI) in one scan. The readout part is a gradient and spin-echo combination (GRASE) that uses switched gradient rephrasing of signals to produce several times as many signals as turbo-spin-echo, which translates into faster imaging time and higher signal-to-noise ratio (SNR) per imaging time. The technique provides the possibility for model based quantification of cerebral blood flow and the determination of the bolus arrival information without use of contrast agent and thus the characterization and determina-tion of regions that are supported by collaterals. Results: Whereas for a quantification of the permeability using ASL the SNR is not high enough, at least qualitative permeability maps can be determined, if an optimal homogenous SNR was guaranteed. This was accomplished in brain regions with a high blood supply, typically given in tumors, and by using a correction for coil sensitivity at the highest possible additional scaling. Conclusion: The single-shot 3D GRASE ASL can provide information about the principal blood supply, the transit delay of the blood flow due to a stenosis or collaterals and a qualitative measure of the permeability.

CO_(2)BOLD assessment of moyamoya syndrome:Validation with single photon emission computed tomography and positron emission tomography imaging

AIM To compare the assessment of cerebrovascular reserve(CVR) using CO_2 BOLD magnetic resonance imaging(MRI) vs positron emission tomography(PET) and single photon emission computed tomography(SPECT) as reference standard.METHODS Ten consecutive patients(8 women, mean age of 41 ± 26 years) with moyamoya syndrome underwent 14 presurgical evaluations for external-internal carotid artery bypass surgery. CVR was assessed using CO_2 BOLD and PET(4)/SPECT(11) with a maximum interval of 36 d, andevaluated by two experienced neuroradiologists.RESULTS The inter-rater agreement was 0.81 for SPECT(excellent), 0.43 for PET(fair) and 0.7 for CO_2 BOLD(good). In 9/14 cases, there was a correspondence between CO_2 BOLD and PET/SPECT. In 4/14 cases, CVR was over-estimated in CO_2 BOLD, while in 1/14 case, CVR was underestimated in CO_2 BOLD. The sensitivity of CO_2 BOLD was 86% and a specificity of 43%. CONCLUSION CO_2 BOLD can be used for pre-surgical assessment of CVR in patients with moyamoya syndrome and combines the advantages of absent irradiation, high availability of MRI and assessment of brain parenchyma, cerebral vessels and surrogate CVR in one stop.

Antenatal and postnatal management of congenital cystic adenomatoid lung malformation diagnosed by ultrasound and Magnetic Resonance Imaging (MRI)

Purpose: Antenatal diagnosis of congenital cystic adenomatoid lung malformation (CCAM) is vital for disease surveillance and postnatal care. Ultrasonography (US) has been the imaging gold standard for antenatal CCAM assessment. However, one of the limitations of US is the “vanishing phenomenon” caused by isoechogenicity of CCAM tissue and adjacent normal lung parenchyma. Methods: Antenatal serial US were concurrently used with magnetic resonance imaging (MRI) to monitor macro- and microcystic lesions. Results: In both pregnant women, antenatal US and MRI confirmed the presence, in the fetus, of cystic lesions and predicted disease regression/progression as well as the need for postnatal surgical intervention. Several advantages were detected by using both—serial US and MRI (over serial US alone)—including improved signal intensity, exact volume size measurements, precise CCAM location in particular for patients with adverse ultrasound conditions. Both neonates underwent surgical resection and had an uneventful post-operative course. Conclusions: Antenatal use of MRI as well as serial US improved information regarding tissue resolution and delineation of CCAM. The information from two imaging modalities was complementary. Our literature review confirmed the emerging role of prenatal MRI for postnatal monitoring and management of CCAM.

Ultrasound screening of the kidneys and urinary tract in 11.887 newborn infants: A 10-year experience

Objective: To determine the usefulness of sonographic screening of the newborn kidneys and urinary tract over a 10-year time period. Methods: Ultrasound screening of the kidneys and the urinary tract was performed between the third and tenth day after birth on 11.887 newborn infants. The classification of renal pyelectasis (RPE) according to the Society for Fetal Urology (SFU) was used. We evaluated infant renal pathologies and correlated them with the gestational age and weight at birth. Results: Renal pyelectasis (grades 1-4) was detected in 179 cases (1.5%);it was significantly more common in male (vs female) infants (p 4.000 g were the most significant risk factors (p < 0.01). Conclusions: Renal pyelectasis grades 1-4 was detected in only 1.5% of 11.887 consecutive infants subjected to sonographic screening of the kidneys and the urinary tract within the first 10 days after birth. Sonographic screening of the kidneys and the urinary tract is a non-invasive and effective screening method after birth. It allows planning for appropriate diagnostic tests and therapeutic procedures in a timely fashion.

Perinatal morbidity and early neonatal mortality in twin pregnancies

Purpose: The purpose of this study was to investigate the impact of maternal, fetal and obstetric parameters in twin pregnancies due to chorionicity, perinatal morbidity and early neonatal mortality. Methods: Early neonatal outcome parameters were retrospectively analysed in 240 twin pregnancies (51 monochorionic [MC], 189 dichorionic [DC] twins) over a 7.5 years period. Beside chorionicity, we focused on risk factors affecting perinatal morbidity and early neonatal outcome in the overall study cohort and subgroups 1) late preterm and 2) pregnancies conceived by artificial fertilization (IVF/ICSI). Mixed effects logistic regression models were used for multivariate risk analyses. Results: MC vs DC pregnancies showed significantly lower birth weights (p 25% and amniotic inflammation (amniotic infection syndrome [AIS]). A gestational age >36 completed weeks was accompanied by a decrease of early neonatal complications

Computational Fluid Dynamics and Its Impact on Flow Measurements Using Phase-Contrast MR-Angiography

Rationale and Objectives: Computational fluid dynamic (CFD) simulations are discussed with respect to their potential for quality assurance of flow quantification using commercial software for the evaluation of magnetic resonance phase contrast angiography (PCA) data. Materials and Methods: Magnetic resonance phase contrast angiography data was evaluated with the Nova software. CFD simulations were performed on that part of the vessel system where the flow behavior was unexpected or non-reliable. The CFD simulations were performed with in-house written software. Results: The numerical CFD calculations demonstrated that under reasonable boundary conditions, defined by the PCA velocity values, the flow behavior within the critical parts of the vessel system can be correctly reproduced. Conclusion: CFD simulations are an important extension to commercial flow quantification tools with regard to quality assurance.

脊柱旁肌水-脂肪MRI测量与等长肌力测量的关系

目的基于化学位移编码的水-脂肪MRI衍生的脊髓旁肌肉质子密度脂肪分数(PDFF)已成为肌肉减少、腰痛、损伤和神经肌肉疾病病人的替代标志物。本研究旨在探讨椎旁肌PDFF及横断面面积(CSA)对等长肌力的预测能力。

Microstructural analysis of pineal volume using trueFISP imaging

AIM:To determine the spectrum of pineal microstructures (solid/cystic parts) in a large clinical population using a high-resolution 3D-T2-weighted sequence. METHODS:A total of 347 patients enrolled for cranial magnetic resonance imaging were randomly included in this study. Written informed consent was obtained from all patients. The exclusion criteria were artifacts or mass lesions prohibiting evaluation of the pineal gland in any of the sequences. True-FISP-3D-imaging (1.5-T, isotropic voxel 0.9 mm) was performed in 347 adults (55.4 ± 18.1 years). Pineal gland volume (PGV), cystic volume, and parenchyma volume (cysts exclud- ed) were measured manually. RESULTS:Overall, 40.3% of pineal glands were cystic. The median PGV was 54.6 mm 3 (78.33 ± 89.0 mm 3 ), the median cystic volume was 5.4 mm 3 (15.8 ± 37.2mm 3 ), and the median parenchyma volume was 53.6 mm 3 (71.9 ± 66.7 mm 3 ). In cystic glands, the standard deviation of the PGV was substantially higher than in solid glands (98% vs 58% of the mean). PGV declined with age (r = -0.130, P = 0.016). CONCLUSION:The high interindividual volume variation is mainly related to cysts. Pineal parenchyma volume decreased slightly with age, whereas genderrelated effects appear to be negligible.

肝硬化中肝细胞癌的动态对比增强CT成像:根据示踪动力学模型行延迟双期检查方案的可行性

应用双期动态对比增强成像对4例肝细胞癌行CT检查．首先应用初始快速动态成像观察早期强化用以评估灌注情况,其后应用逐渐增加时间间隔的延迟成像来监测随后的组织增强表现以评估组织通透性。利用双人路双室分布参数模型来分析动态对比增强CT影像．分别评估血流量和通透性及血管内外容积分数。结果表明,半透膜分隔的双室模型能恰当地显示肝细胞癌和周围肝硬化组织的增强曲线。与背景肝组织相比,肝细胞癌的强化更早。

脑MRI影像组学在预测转移瘤类型中的应用

目的探讨在未知原发病灶的病人中,运用多分类机器学习方法中不同脑转移瘤的MRI影像组学特征预测肿瘤类型的可行性。材料与方法这项单中心回顾性分析纳入189例病人(女101例,男88例;年龄32~85岁,平均61岁)共658幅脑转移瘤的MR影像,包括T1平扫、T1增强与液体衰减反转恢复(FLAIR)序列影像。

扩散张量成像对于正常脑表现的发育迟缓儿童胼胝体微观结构异常的显示

胼胝体纤维在精神运动和认知功能等方面具有重要作用。本研究的目的是对常规MRI脑表现正常的发育迟缓的儿童进行研究,探讨其胼胝体存在微观结构异常的可能性。本组研究对象为17例发育迟缓的患儿（年龄1-9岁）。分别在胼胝体膝部和压部测量T2值和部分各向异性（FA）值。除了对胼胝体行纤维示踪、容积测定外,还计算纤维密度。测量结果同年龄相匹配的健康受试者比较。疾病组胼胝体膝部的T2值普遍升高（疾病组105ms／正常组95ms）,

Simultaneous Echo Refocused Magnetization Transfer Imaging

Purpose: To increase the efficiency of densely encoded magnetization transfer imaging of the brain, we time-multiplex multiple slices within the same readout using simultaneous echo refocusing FLASH imaging with magnetization transfer (MT) preparation (MT-SER-FLASH). Materials and Methods: Inefficiency in total scan time results from the number of frequency samples needed for sufficient quality of quantitative parameter maps for a binary spin bath model. We present a highly efficient multiplexing method, simultaneous echo refocused magnetization transfer imaging (MT-SER-FLASH) for reducing the total scan time of MT imaging by one-third. The specific absorption rate (SAR) was also reduced by reducing the number of MT-pulses per volume. Results: 2D-MT-SER-FLASH is performed in 19 minutes rather than 1 hour, acceptable for routine clinical application. The SAR could be reduced to 69% instead of more than 100% with a standard 2D or 3D-FLASH with MT-preparation. Conclusion: The net reduction of scan time and SAR enables the use of quantitative model based magnetization transfer imaging within a clinical environment.

Successful coil embolization with a basic technique for ruptured posterior tibial artery in a patient with Ehlers-Danlos syndrome type IV: A case report

The surgical management of vascular complication with Ehlers-Danlos Syndrome type IV (EDS-IV) is extremely challenging because of its tissue or organ fragility including arteries. Less traumatic maneuvers and devices have been recommended to perform the endovascular treatment for the vascular lesion of EDS-IV, although the endovascular procedure is less invasive than surgical intervention. We report a 23-year-old man with EDS-IV suffered from left posterior tibial arterial rupture. We performed internal trapping of the ruptured segment using detachable coils with a standard technique via the contralateral femoral artery puncture. The patient was discharged without any complication associated with the endovascular procedure. Embolization by a basic technique, performed with greatest care, is a safe and useful treatment option which we radiologists should try for managing EDS-IV patients.

MR磁敏感加权成像评价轻度认知障碍者的脑内微出血和铁沉积

目的探讨MR磁敏感加权成像是否有助于在基线水平预测认知的下降。材料与方法本项前瞻性研究得到学术审查委员会批准,所有病人均签署知情同意书。

Modelling Magnetization Transfer Considering Spin-Locking Effects

Purpose: Recently it was demonstrated that spin-locking (SL) effects can manifest as pseudo magnetization transfer (MT). To our best knowledge the MT models proposed so far cannot distinguish between saturation effects caused by the MT preparation pulses and SL phenomena. Therefore a new MT model is proposed. Materials and Methods: A binary spin-bath model for magnetization transfer was extended in that sense that SL effects are considered. The new modified spin bath model was tested for a phantom with different agar concentrates (2%, 4%, 8%) and a MnCl2 (0.3 mM) solution. Results: The mean fitting error is 3.2 times lower for the modified model compared to the original model. Especially the parameter F for the fractional part of the bounded proton pool describes the situation for the MnCl2 (F = 0) better than the original model (F = 0.004). Conclusion: The proposed mathematical modifications of the binary spin-bath model considering SL seem to be a step in the right direction in that sense that the effects associated with SL are not interpreted as magnetization transfer.

Treatment practice of vasospasm during endovascular thrombectomy: an international survey

Background and aim The clinical importance and management of vasospasm as a complication during endovascular stroke treatment(EVT)has not been well studied.We sought to investigate current expert opinions in neurointervention and therapeutic strategies of iatrogenic vasospasm during EVT.Methods We conducted an anonymous international online survey(4 April 2023 to 15 May 2023)addressing treatment standards of neurointerventionalists(NIs)practising EVT.Several illustrative cases of patients with vasospasm during EVT were shown.Two study groups were compared according to the NI’s opinion regarding the potential influence of vasospasm on patient outcome after EVT using descriptive analysis.Results In total,534 NI from 56 countries responded,of whom 51.5%had performed>200 EVT.Vasospasm was considered a complication potentially influencing the patient’s outcome by 52.6%(group 1)whereas 47.4%did not(group 2).Physicians in group 1 more often added vasodilators to their catheter flushes during EVT routinely(43.7%vs 33.9%,p=0.033)and more often treated severe large-vessel vasospasm with vasodilators(75.3%vs 55.9%;p<0.001),as well as extracranial vasospasm(61.4%vs 36.5%,p<0.001)and intracranial medium-vessel vasospasm(27.1%vs 11.2%,p<0.001),compared with group 2.In case of a large-vessel vasospasm and residual and amenable medium-vessel occlusion during EVT,the study groups showed different treatment strategies.Group 2 continued the EVT immediately more often,without initiating therapy to treat the vasospasm first(9.6%vs 21.1%,p<0.001).Conclusion There is disagreement among NIs about the clinical relevance of vasospasm during EVT and its management.There was a higher likelihood of use of preventive and active vasodilator treatment in the group that perceived vasospasm as a relevant complication as well as differing interventional strategies for continuing an EVT in the presence of a large-vessel vasospasm.

Effect of thrombectomy on oedema progression and clinical outcome in patients with a poor collateral profile

Background and purpose The impact of the cerebral collateral circulation on lesion progression and clinical outcome in ischaemic stroke is well established.Moreover,collateral status modifies the effect of endovascular treatment and was therefore used to select patients for therapy in prior trials.The purpose of this study was to quantify the effect of vessel recanalisation on lesion pathophysiology and clinical outcome in patients with a poor collateral profile.Materials and methods 129 patients who had an ischaemic stroke with large vessel occlusion in the anterior circulation and a collateral score(CS)of 0-2 were included.Collateral profile was defined using an established 5-point scoring system in CT angiography.Lesion progression was determined using quantitative lesion water uptake measurements on admission and follow-up CT(FCT),and clinical outcome was assessed using modified Rankin Scale(mRS)scores after 90 days.Results Oedema formation in FCT was significantly lower in patients with vessel recanalisation compared with patients with persistent vessel occlusion(mean 19.5%,95%CI:17%to 22%vs mean 27%,95%CI:25%to 29%;p<0.0001).In a multivariable linear regression analysis,vessel recanalisation was significantly associated with oedema formation in FCT(ß=−7.31,SD=0.015,p<0.0001),adjusted for CS,age and Alberta Stroke Program Early CT Score(ASPECTS).Functional outcome was significantly better in patients following successful recanalisation(mRS at day 90:4.5,IQR:2-6 vs 5,IQR:5-6,p<0.001).Conclusion Although poor collaterals are known to be associated with poor outcome,endovascular recanalisation was still associated with significant oedema reduction and comparably better outcome in this patient group.Patients with poor collaterals should not generally be excluded from thrombectomy.

Impact of aspiration catheter size on first-pass effect in the combined use of contact aspiration and stent retriever technique

Background and purpose The first-pass effect(FPE),defined as a first-pass Expanded Treatment in Cerebral Ischaemia(eTICI)2c/3 reperfusion,has emerged as a key metric of efficacy in mechanical thrombectomy(MT)for acute ischaemic stroke.The proximal balloon occlusion together with direct thrombus aspiration during stent retriever thrombectomy(PROTECT)-PLUS technique consists in the use of a balloon guide catheter and a combined MT approach involving contact aspiration and a stent retriever.The aim of this study is to assess the effectiveness and safety of the PROTECT-PLUS technique using distal aspiration catheters(DACs)with different inner diameters by comparing the large-bore DAC Catalyst 7 versus the use of medium-bore DACs.Methods Retrospective analysis of a prospectively maintained database of patients treated with PROTECT-PLUS using Catalyst 7,Catalyst 6 or Catalyst 5 with an occlusion of either the terminal carotid artery or the M1 or M2 segments of the middle cerebral artery from 2018 to 2020 in two comprehensive stroke centres.Baseline characteristics and procedural,safety and clinical outcomes were compared between groups.Multivariable logistic regression analysis was performed in order to find independent predictors of FPE.Results We identified 238 consecutive patients treated with PROTECT-PLUS as front-line approach using Catalyst 7(n=86),Catalyst 6(n=78)and Catalyst 5(n=76).The rate of FPE was higher with Catalyst 7(54%)than Catalyst 6(33%,p=0.009)and Catalyst 5(32%,p=0.005),in addition to higher final eTICI 2c/3 reperfusion rates,shorter procedural times,lower need of rescue therapy and fewer procedure-related complications.After multivariable analysis the sole independent factor associated to FPE was the use of Catalyst 7(OR 2.34;95%CI 1.19 to 4.58;p=0.014).Conclusion Further development of combined MT by incorporating larger-bore aspiration catheters is associated with higher reperfusion rates,shorter procedure times,and lower need of rescue therapy while reducing the complication rates.

Cavernous brain malformations and their relation to black blood MRI in respect to vessel wall contrast enhancement

Background: Inflammatory responses are implicated as crucial patho-mechanisms of vascular brain malformations. Inflammation is suggested to be a key contributor to aneurysm rupture; however it is unclear whether inflammation contributes similarly to bleeding of cerebral cavernous malformations (CCMs). Black blood MRI is a sequence which identifies inflammation in blood vessel walls and in the present study is used to detect inflammatory response in CCMs. Methods: Fifteen patients with 17 CCMs treated in our department in 2017 were retrospectively analysed. All patients received black blood MRIs and the results were analysed in correlation with, size and bleeding of CCMs. Results: Size and bleeding status of CCMs did not correlate with contrast enhancement in the CCM wall. One of 3 patients with bleeding displayed contrast enhancement in black blood MRI, whereas the others had non enhancing lesions. Because of the small number of cases a statistical analysis was not performed. Conclusion: In this limited cohort, inflammatory reactions in CCMs could not be detected by black blood MRI suggesting that the level of inflammation is minimal in these lesions and those different patho-mechanisms play a more important role in the rupture of CCMs.