Follow-up Magnetic Resonance Angiography Research Articles

Pure arterial malformation of the fetal PCA treated with flow diverter stent-case report and literature review.

Thirty-three-year-old female underwent diagnostic work-up for chronic headaches. Cerebral DSA on the right side showed fetal posterior cerebral artery (PCA) with unusually shaped arterial malformation on its proximal part. Malformation was formed by multiple convolutions and loops with no arteriovenous shunting. During endovascular procedure, flow diverter stent was placed in the right C6 segment. Patient was put on double antiaggregation therapy. Four weeks after procedure, patient was admitted to ER with signs of dyphasia. No recent ischemic lesions were detected on emergent magnetic resonance. Dyphasia resolved spontaneously. On follow-up magnetic resonance angiography 5 years after the procedure, main portion of malformation has diminished with slightly filling of posterior part supplied by right P1. Here, reported finding is consistent with previously described pure arterial malformation (PAM). Main intention of our treatment was to induce malformation remodeling with flow diverter placement. Two main risks arise when using flow diverters on fetal PCA region. Firstly, there is possibility of occluding fetal PCA alongside malformation. On the contrary, high flow through fetal PCA could hinder malformation thrombosis. Some case series reported high rate of fetal PCA occlusion without ischemic sequelae in the PCA teritory. Others consider flow diverters highly ineffective treatment for the fetal PCA aneurysms due to low rate of complete aneurysm occlusion. We presented first reported case in which flow diverter was used to treat PAM. Slow malformation thrombosis leaves enough time for collateral circulation to recruit and supply territory of the vessel affected by the malformation.

Single Neuroform Atlas stent: a reliable approach for treating complex wide-neck bifurcated aneurysms.

Treating wide-neck bifurcated cerebral aneurysms (WNBAs) using various techniques and new devices has shown favorable outcomes. However, endovascular coiling can be technically challenging when the aneurysm neck is incorporated into the parent vessel. Furthermore, although recent research has reported favorable outcomes of Neuroform Atlas stent (NAS)-assisted coiling, broad inclusion criteria have hampered precise evaluations of their effectiveness and safety for treating complex WNBAs. Therefore, this study evaluated whether the use of a single NAS is a safe and effective approach for treating complex WNBAs. We treated 76 complex WNBAs (unruptured, n = 49; ruptured, n = 27) using single NAS-assisted coil embolization and retrospectively analyzed the clinical and angiographic outcomes. In a cohort of 68 patients (mean age, 58.3 ± 11.6 years; males n = 20, 29.4%; females, n = 48, 70.6%), 76 stents were successfully delivered to the target aneurysms, yielding a technical success rate of 98.6%. Complete occlusion was evident in 59 (77.6%) of 76 aneurysms, with neck remnants found in 16 (21.1%) and partial occlusion in 1 (1.3%). Treatment-related morbidities comprised one branch occlusion and one parenchymal hemorrhage. However, no new neurological symptoms of unruptured aneurysms were evident at discharge. The outcomes of 20 of the 27 ruptured aneurysms were favorable (Glasgow Outcome Scale scores of 4 or 5) at the final follow-up assessment (mean 12.2 [6-29] months), except for one initial subarachnoid hemorrhage. Post-treatment angiography revealed complete occlusion in 89.1%, neck remnants in 7.8%, and incomplete occlusion in 3.1% of the aneurysms. Approximately 88.2% of the patients were assessed at least once by follow-up diagnostic or magnetic resonance angiography (mean, 12.5 ± 4.3 [range, 6-29] months), with five (7.8%) minor and two (3.1%) major recurrences. A single NAS is safe and effective for treating WNBAs incorporated into parent vessels.

Long-term clinical and radiological trajectories of craniocervical vasculopathy in children with PHACE syndrome.

To describe the rates of stroke and craniocervical vasculopathy progression in children with posterior fossa malformations, hemangioma, arterial anomalies, coarctation of the aorta/cardiac defects, and eye abnormalities (PHACE) syndrome. A single-center, retrospective natural history study of children with PHACE syndrome. Clinical and sequential neuroimaging data were reviewed to study the characteristics and progression of vasculopathy and calculate the rates of arterial ischemic stroke (AIS) and transient ischemic stroke (TIA). Vasculopathy progression was defined as worsening or new vascular findings on follow-up magnetic resonance angiography. Thirty-four children with cerebrovascular abnormalities at the PHACE syndrome diagnosis were studied (age range = 2 to 18 years, 85% females). Median age at the initial diagnosis was 5.5 months (interquartile range = 1-52 months); median age at the last follow-up was 8 years 6 months (range = 2-18 years). Overall, 10 (29%) patients had radiological progression of their vasculopathy, with a cumulative progression-free rate of 73% (95% confidence interval [CI] = 0.57-0.89), and a cumulative TIA-free and AIS-free rate of 87% (95% CI = 0.745-0.99). Vasculopathy was continuously progressive in six patients (18%) at the last follow-up. Three patients (9%) had TIA and all had progressive vasculopathy. One patient had presumed perinatal AIS at the initial PHACE diagnosis, while no other patient experienced an AIS during the follow-up. In children with PHACE syndrome, craniocervical vasculopathy is non-progressive and asymptomatic in the majority of cases. The risk of ischemic stroke in these children is very low. Larger and prospective studies are necessary to confirm these findings.

Rapid presentation of a de novo intracranial aneurysm: illustrative case.

Intracranial aneurysms are prevalent, particularly with advancing age. De novo aneurysms, occurring independently from the initial lesion, pose a unique challenge because of their unpredictable nature. Although risk factors such as female sex, smoking history, and hypertension have been proposed, the mechanisms underlying de novo aneurysm development remain unclear. A 79-year-old female developed a de novo saccular aneurysm within a year after management of a ruptured vertebral artery dissecting aneurysm. Her complex clinical course involved subarachnoid hemorrhage with diffuse vasospasm, stent occlusion of a dissecting aneurysm, discovery of a right 7- to 8-mm de novo middle cerebral artery aneurysm at the 1-year magnetic resonance angiography follow-up, and successful coil embolization. This rare occurrence challenges established timelines, as most de novo aneurysms manifest over a longer interval. Studies have attempted to identify risk factors, yet consensus remains elusive, particularly regarding the influence of treatment modality on de novo formation rates. This unique case urges reconsideration of posttreatment surveillance protocols, proposing shorter intervals for imaging and more vigilant follow-up strategies to detect asymptomatic de novo aneurysms. Timelier identification could significantly impact patient outcomes by averting potential ruptures. This emphasizes the need for further research to delineate effective monitoring and preventive measures for these enigmatic lesions.

Abstract TP221: Progression of Intracranial Artery Stenosis and Cerebral Small Vessel Disease and Associations Between the Two Entities: A Prospective Community-Based Cohort Study

Background: Both intracranial artery stenosis (ICAS) and cerebral small vessel disease (CSVD) can cause heavy socioeconomic burdens. However, their longitudinal changes remain controversial. To investigate the risk factors for ICAS and CSVD progression and their associations in a community population. Methods: This longitudinal analysis included 756 participants who underwent both baseline and follow-up brain magnetic resonance imaging (MRI) and magnetic resonance angiography from Shunyi cohort. The follow-up duration was 5.58±0.49 years. Incident ICAS was defined as new stenosis occurring in at least one artery or increased severity of the original artery stenosis. CSVD markers included lacunes, cerebral microbleeds (CMB), and white matter hyperintensities (WMH). Results: Of the 756 participants (aged 53.7±8.0 years, 34.9% men), 8.5% had incident ICAS. Body mass index (BMI) and diabetes mellitus are independent risk factors for ICAS. Hypertension is an independent risk factor for incident lacunes and CMB, whereas WMH progression is primarily affected by BMI. Higher LDL cholesterol level independently protects against WMH progression. Baseline ICAS burden predicted an increased risk of incident lacunes (odds ratio [OR] = 2.17, 95% confidence interval [CI] = 1.10-4.29, p = 0.025) after adjusting for age, sex, follow-up time, vascular risk factors, and baseline lacunes burden. Incident ICAS was also significantly associated with incident lacunes (OR = 3.29, 95% CI = 1.61-6.72, p = 0.001). No significant correlation was identified between ICAS and CMB or WMH. Conclusions: Patients with ICAS and CSVD progression had different modifiable risk factor profiles. The disparate association between ICAS and progressions of different MRI markers of CSVD imply vital differences of their underline mechanism.

Left Transradial Access Using a Radial-Specific Neurointerventional Guiding Sheath for Coil Embolization of Anterior Circulation Aneurysm Associated With the Aberrant Right Subclavian Artery: Technical Note and Literature Review

Aberrant right subclavian artery (ARSA) is a rare condition, but the most common anomaly of the aortic arch. Although neurointerventions via transradial access (TRA) are becoming increasingly popular worldwide, transradial carotid cannulation has been extremely challenging in patients with an ARSA. Herein, we present a case of ARSA-associated anterior communicating artery (ACoA) aneurysm that was successfully treated with a radial-specific 6F Simmons guiding sheath via left TRA. We also review the relevant literature. A 68-year-old-woman who was diagnosed as having an ARSA-associated ACoA aneurysm underwent simple coiling via left TRA. After the 6F Simmons guiding sheath was engaged into the right common carotid artery using the pull-back-technique, transradial quadraxial system (6F Simmons guiding sheath/6F intermediate catheter/3.2F intermediate catheter/coil-delivery microcatheter) was implemented. Simple coiling of the aneurysm was successfully achieved without catheter kinking or system instability. The postprocedural course was uneventful. A follow-up magnetic resonance angiography showed no evidence of recanalization 1 years 9 months after the procedure. Transradial anterior circulation intervention has been rarely used for patients with an ARSA due to unfavorable catheter trajectory. Left TRA using the 6F Simmons guiding sheath is a useful treatment option to address anterior circulation interventions for patients with an ARSA. Preoperative diagnosis of ARSA is necessary for the application of our method.

Flow Diverter Treatment Using a Flow Re-Direction Endoluminal Device for Unruptured Intracranial Vertebral Artery Dissecting Aneurysm: Single-Center Case Series and Technical Considerations.

This study aimed to evaluate the effectiveness, safety, and technical considerations of flow diverter (FD) treatment using a Flow Re-direction Endoluminal Device (FRED) for unruptured intracranial vertebral artery dissecting aneurysms (VADAs). We conducted a retrospective study of 23 patients with unruptured intracranial VADAs who underwent FD treatment using a FRED between June 2017 and August 2021. Symptoms, imaging findings, treatment strategies, and angiographic and clinical outcomes were evaluated. Dissections were categorized according to the dominance of the VA in which they occurred: dominant VA, co-dominant VA, and non-dominant VA. All patients successfully underwent FD treatment with either a FRED (n=11) or FRED Jr. (n=12). Complete occlusion rates were 78.3% at 6-month follow-up magnetic resonance angiography and 91.3% at 12-month. There were no instances of complications, recurrence, or retreatment during a median follow-up of 20 months. Dissections occurred in the dominant VA in 3 cases (13.0%), the co-dominant VA in 13 cases (56.5%), and the non-dominant VA in 7 cases (30.4%). Intimal flap and true lumen stenosis were observed in 39.1% and 30.4% of cases, respectively. Four cases required a bilateral VA approach due to technical difficulties, all in the non-dominant VA. Flow diversion treatment using a FRED for unruptured intracranial VADAs proved feasible and safe, yielding satisfactory occlusion rates. Technical challenges were more likely in lesions involving non-dominant VAs in the acute or subacute stage, mainly due to associated intraluminal lesions compromising the arterial lumen.

5613354 SCREENING FOR CEREBROVASCULAR DISEASE IN CHILDREN WITH SICKLE CELL DISEASE USING TRANSCRANIAL DOPPLER AND MRA TO PREVENT STROKE: THE AMSTERDAM COHORT

Background: Cerebrovascular complications are the most devastating complications in patients with Sickle Cell Disease (SCD). To identify patients at risk of a first cerebrovascular accident (CVA), the American Society of Hematology (ASH) 2020 guideline for SCD recommends annual transcranial Doppler ultrasonography (TCD) screening for children aged 2-16 years with HbSS or HbSβ0 thalassemia. When abnormal TCD velocities are detected, chronic transfusion therapy is advised for at least a year.(1) Since 2000 we have implemented a different management protocol in Amsterdam that only prescribes transfusion therapy for children with confirmed MRA abnormalities when increased flow is present on TCD measurement. This Amsterdam protocol reduces exposure to chronic blood transfusions but we need to investigate the safety and efficacy. Methods: In this longitudinal single center cohort study, all patients managed according to the Amsterdam Protocol between January 2000 and September 2022 were included. TCD screening was performed in children with genotypes SS or Sβ0-thalassemia at a frequency of twice a year in the age group 4-10 years and annually in children aged 10 to 18 years. From January 1st 2010 onwards, screening was already initiated at the age of 2 years. When TCD screening demonstrated abnormal results at 2 separate assessments, magnetic resonance angiography (MRA) was performed. We only started chronic transfusion therapy in patients with a stenotic lesion present on MRA. In patients without abnormalities on MRA follow-up by TCD according to protocol was continued. Results: A total of 209 SCD patients were included in this study, cumulative 2874.5 patient-years of follow-up. The median age of these patients at the start of the follow-up was 0.74 (IQR: 0.0, 5.5) years. In this cohort, 30 patients had abnormal TCD results at 2 separate assessments. In all of these patients MRA was performed, which showed abnormal results in 16 cases. None of the 12 patients with abnormal TCD results and normal MRA results who did not receive chronic transfusion therapy developed a CVA. The total follow-up duration after the first abnormal TCD in these patients was 112.0 patient-years. Nine out of the 14 patients (64%) who had abnormal TCD results used hydroxyurea. The median time between the first abnormal TCD and initiation of hydroxyurea therapy was 3.9 (IQR: 3.0, 5.2) years. Two patients with abnormal TCD and normal MRA results were treated with chronic transfusion therapy. In these cases, chronic transfusion therapy was started because of recurrent acute chest syndrome (ACS) and abnormal TCD results (despite normal MRA results) respectively. Discussion: These data suggest that treatment according to the Amsterdam Protocol is a safe and efficient way to prevent primary stroke in children with SCD and to reduce exposure of these patients to long term transfusion therapy. Although the group of patients in this cohort with abnormal TCD velocities and normal MRA that did not receive transfusion therapy is limited to 12 patients with cumulative 112.0 patient-years of follow-up, we believe the results of this study are reassuring, since the cumulative incidence rate in this study is significantly lower (0.0 (95% CI: 0.0, 0.25)) compared to the incidence reported for patients with abnormal Doppler results in the original study by Adams et al. (0.4 (95% CI: 0.27, 0.59) at 30 months).(2)

Use of Non-Contrast-Enhanced MR Angiography to Assess Recanalization after Uterine Artery Embolization

The purpose of this study was to examine the use of non-contrast-enhanced MR angiography (MRA) for assessing recanalization of uterine arteries (UAs) after uterine artery embolization (UAE) for symptomatic fibroids. Pre-procedural and follow-up unenhanced MRA images of 30 patients were reviewed, and the extent to which the UAs could be visualized was classified on a 4-point scale. An increase in the score between consecutive time points indicates that a previously inconspicuous segment of the UA became visible on follow-up images. Patients were divided into two groups according to the presence (or absence) of recanalization. The median UA visualization score at each follow-up was significantly lower than that at baseline (p < 0.01), but there was no significant difference between the scores of the follow-up images. Recanalization was detected in 63% (19/30) of patients. In these patients, the mean decrease in uterine and largest fibroid volume at 12 months after UAE was inferior to the mean decrease in patients for whom recanalization was not detected. Based on MRA assessment, recanalization after UAE occurred in 63% of patients but did not compromise the reduction in uterine and dominant fibroid volumes within 12 months after UAE.

Predictors of improvement for patients with CNS vasculitis stenoses: A high-resolution vessel wall MRI follow-up study

PurposeTo investigate the predictors of the improvement for patients with isolated intracranial vasculitis stenoses using high-resolution vessel wall magnetic resonance imaging (HR VW-MRI). MethodsWe retrospectively reviewed data from consecutive patients with confirmed intracranial vasculitis under the same conventional conservative treatment based on a prospectively established HR VW-MRI database between December 2016 and December 2020. According to the changes between the degree of stenosis at baseline compared to follow-up MR angiography, the patients were divided into an improvement group and a non-improvement group. A multivariate analysis was performed to identify the predictive factors associated with the improvement of stenoses secondary to intracranial vasculitis. ResultsOverall, 41 patients (mean age 32.0 ± 10.1 years, 16 females) with isolated intracranial vasculitis stenoses were included (41.5 % [17/41] in the improvement group, and 58.5 % [24/41] were in the non-improvement group). The degree of wall enhancement on follow-up imaging was significantly reduced compared with that on the baseline imaging in the improvement group (P = 0.004). The multivariate analysis showed that the degree of enhancement (OR, 0.219, 95 % CI, 0.054 to 0.881; P = 0.033) at baseline was an independent predictive factor associated with the improvement in the intracranial vasculitis stenoses. ConclusionsIn patients with isolated intracranial vasculitis stenoses, the less enhancement the vessel wall was, the more likely the degree of stenosis would be reduced by conventional conservative therapy.

Transradial Stent-Assisted Coiling Using “Dual-Jailing” Technique for Kissing Aneurysms of the Internal Carotid Artery: Technical Note and Literature Review

Kissing aneurysms are an unusual type of multiple intracranial aneurysms having different origins with partially adherent walls. Although endovascular treatment is a useful alternative to surgical clipping, endovascular management for small wide-necked kissing aneurysms has not been adequately investigated to date. Herein, we present a case of small wide-necked kissing aneurysms successfully treated with transradial stent-assisted coiling (SAC) using the "dual-jailing" technique. We also performed a review of the relevant literature. A 64-year-old woman who was diagnosed with small wide-necked kissing aneurysms relating to the ophthalmic artery underwent SAC using the dual-jailing technique. After a 6F Simmons guiding sheath was delivered into the target common carotid artery via transradial access, a 6F intermediate catheter was navigated into the petrous internal carotid artery to achieve both triple microcatheter manipulation and contrast injection. Two coil-delivery microcatheters were cannulated into each aneurysm, followed by a Neuroform Atlas stent deployment over the aneurysm necks via a third stent-delivery microcatheter. By using the jailed microcatheters, SAC of the kissing aneurysms was successfully achieved, preserving the ophthalmic artery. The postprocedural course was uneventful. A follow-up magnetic resonance angiography showed no evidence of recanalization 2years 3months post procedure. The dual-jailing technique may provide simple and time-saving SAC compared with previous reported method. This technique can be a useful treatment option for small wide-necked kissing aneurysms.

Outflow Patency Correlates with Radiosurgical Outcomes of Lateral Sinus Dural Arteriovenous Fistula.

To explore the impact of outflow patency on radiosurgical outcomes of lateral sinus dural arteriovenous fistulas (DAVFs). We retrospectively examined 83 lateral sinus DAVFs treated with Gamma Knife radiosurgery (GKRS) between 1995 and 2020. Two neuroradiologists blinded to the therapeutic outcomes served as imaging evaluators on pre-GKRS digital subtraction angiography and magnetic resonance images. The sinovenous outflow of lateral sinus DAVF was scored using combined conduit score (CCS), ranging from 0 (total occlusion) to 8 (full patency). The patients' follow-up magnetic resonance and digital subtraction angiography images were used to validate the radiosurgical outcomes (obliteration or non-obliteration) of lateral sinus DAVF. Cox regression and Kaplan-Meier analyses were performed to determine the correlations between the variables and outcomes. Among the 83 cases, 60 (72%) lateral sinus DAVFs achieved obliteration after a GKRS at a median latency period of 24.5months. After adjustment for aggressive presentation, cortical venous reflux, straight sinus reflux, and optic nerve sheath enlargement, a CCS of >6 was independently associated with lateral sinus DAVF obliteration (hazard ratio: 2.335, P=0.007). The estimated 36-month probabilities of obliteration were 80% versus 53.6% for lateral sinus DAVFs with a CCS of >6 versus ≤6. Lateral sinus DAVFs with a CCS of >6, indicating a nearly patent sinovenous outflow, were more likely to be obliterated after GKRS. Sinovenous outflow patency is a factor associated with therapeutic outcomes in radiosurgery for lateral sinus DAVFs.

Prediction of Intracranial Aneurysm Rupture Risk Using Non-Invasive Radiomics Analysis Based on Follow-Up Magnetic Resonance Angiography Images: A Preliminary Study

This is the first preliminary study to develop prediction models for aneurysm rupture risk using radiomics analysis based on follow-up magnetic resonance angiography (MRA) images. We selected 103 follow-up images from 18 unruptured aneurysm (UA) cases and 10 follow-up images from 10 ruptured aneurysm (RA) cases to build the prediction models. A total of 486 image features were calculated, including 54 original features and 432 wavelet-based features, within each aneurysm region in the MRA images for the texture patterns. We randomly divided the 103 UA data into 50 training and 53 testing data and separated the 10 RA data into 1 test and 9 training data to be increased to 54 using a synthetic minority oversampling technique. We selected 11 image features associated with UAs and RAs from 486 image features using the least absolute shrinkage and the selection operator logistic regression and input them into a support vector machine to build the rupture prediction models. An imbalanced adjustment training and test strategy was developed. The area under the receiver operating characteristic curve, accuracy, sensitivity, and specificity were 0.971, 0.948, 0.700, and 0.953, respectively. This prediction model with non-invasive MRA images could predict aneurysm rupture risk for SAH prevention.

Evaluation of Occluded Distal Vessels with Variable Flip-Angle 3-Dimensional Turbo Spin-Echo Magnetic Resonance Imaging Before Acute Mechanical Thrombectomy

The aim of this study was to evaluate the course of occluded distal vessels before mechanical thrombectomy (MT) for acute large vessel occlusion (LVO) with non-contrast magnetic resonance imaging (MRI). The variable flip-angle three-dimensional turbo spin-echo (VRFA-3D-TSE) method was used to evaluate the course of occluded distal vessels quickly and clearly in acute LVO cases before MT. Patients with acute LVO who were indicated for MT between April 2021 and March 2022 were examined by the VRFA-3D-TSE method to evaluate the distal course of occluded vessels. We included internal carotid artery (ICA) occlusion, M1 occlusion of the middle cerebral artery, and basilar artery (BA) occlusion. Preoperative images were compared to the angiographic findings after recanalization or with follow-up magnetic resonance angiography, and the results were assessed by 2 endovascular treatment specialists as excellent, good, or poor imaging. MT was performed in a total of 27 patients. There were 17 patients with intracranial occlusion of the ICA, M1, and BA. Occlusion was found in the intracranial ICA in 6 patients, the M1 in 7, and the BA in 4. VRFA-3D-TSE MRI was performed in all patients, and the imaging was rated (by the 2assessors) as excellent in 12 of 17 and 14 of 17 cases, good in 5 of 17 and 3 of 17 cases, and poor in 0 of 17 cases. In patients with acute LVO, VRFA-3D-TSE MRI enabled rapid and good depiction of the course of occluded distal vessels before MT without the use of contrast medium.

Compressive optic neuropathy caused by a flow-diverter-occluded-but-still-growing supraclinoid internal carotid aneurysm: illustrative case

BACKGROUNDFlow diverter stenting is an effective treatment for large proximal internal carotid artery (ICA) aneurysms. Cranial neuropathy caused by the mass effect of the aneurysm usually subsides over time. However, a new onset of compressive optic neuropathy after successful flow diverter stenting of a large proximal ICA aneurysm is seldom reported.OBSERVATIONSA 57-year-old woman had a right supraclinoid ICA aneurysm (approximately 17 mm) on magnetic resonance angiography (MRA) in a health checkup. She received intervention with the Pipeline embolization device. Six months later, she started to experience progressive hemianopia in the left half of the visual field. Nine months after stenting, MRA showed that the aneurysm was growing and causing mass effect, but digital subtraction angiography confirmed that the aneurysm was completely excluded from the circulation. She received a craniotomy for microsurgical decompression of the optic nerve and coagulation shrinkage of the aneurysm. Clipping and thrombectomy were not attempted. Her visual fields recovered gradually. Follow-up MRA showed that the aneurysm also diminished in size.LESSONSWhether the coagulation technique of the flow-diverter-occluded aneurysm alone is enough to cause satisfactory shrinkage and interaction between the flow diverter and the aneurysmal vasa vasorum/neointima formation should be further examined.

Treatment of a 4-year-old boy with mepolizumab for lymphocytic hypereosinophilic syndrome

A previously healthy 4-year-old boy presented to the emergency department with 2 days of headache, unsteady gait, and left hemiparesis. Emergent head computed tomography revealed a right-sided hypodensity concerning for ischemic stroke. Follow-up magnetic resonance imaging and magnetic resonance angiography revealed multiple acute ischemic foci in the right middle cerebral artery and posterior cerebral artery watershed territories, chronic appearing ischemic foci bilaterally, and bilateral carotid artery narrowing concerning for medium or large vessel vasculitis.

Failure of Flow-Diverter Endothelization Visualized with Optic Coherent Tomography Technology

We report a case of an intracranial aneurysm of the left posterior inferior cerebellar artery, which was treated with a flow-diverting stent. One year later at follow-up, the patient presented with new symptoms due to mass effect in the posterior fossa and a 3-fold enlargement of the aneurysm. Digital subtraction angiography showed an increase in size of the aneurysm with jet flow into the sac. Optic coherent tomography was performed during the procedure, demonstrating a failure of endothelization of the stent with a focal 1-mm opening at the neck of the aneurysm, resulting in jet flow. Parent vessel sacrifice was performed by coiling of the left vertebral artery. The patient had a codominant right vertebral artery and tolerated the procedure well. Two years later, follow-up magnetic resonance angiography showed significant decrease of the size of the aneurysm and symptom regression, with a modified Rankin scale of 1 (functionally independent).

Abstract WP176: Compared To Catheter Angiogram MRA Is A Moderate Predictor Of Suzuki Grade In Children With Moyamoya

Introduction: Moyamoya is a progressive cerebral arteriopathy affecting the arteries in the circle of Willis. Suzuki grade for moyamoya using catheter angiogram has been gold standard for the evaluation of moyamoya both in children and adults. Suzuki grade evaluates the amount of stenosis and collateral formation in the cerebral arteries. Magnetic resonance angiography (MRA) non-luminal imaging can overestimate stenosis and underestimate collaterals. With greater use of MRA for diagnosis and follow-up, it is important to understand MRA staging is truly comparable to catheter angiogram. Methods: Study neurologist and interventional radiologist reviewed both catheter angiograms and MRAs without clinical information. The modified Suzuki stage was used to evaluate the MRA. Median time from MRA to catheter angiogram was calculated. Cohen’s Kappa was used to compare modalities of Suzuki grade based on catheter angiogram to modified Suzuki grade by MRA on the same patients. Results: A total of 29 patients with moyamoya were reviewed. Median time between MRA and catheter angiogram was 2.4 months with interquartile range from 0.6-5.3 months. Unweighted Cohen’s Kappa was 0.34 (p&lt;0.0001) which is considered fair correlation. When we calculated a weighted Cohen’s Kappa it improved but only to 0.49 (p&lt;0.0001) which is moderate correlation. Conclusion: Using Cohen’s kappa to compare two methods of evaluating cerebral artery stenosis in children with moyamoya, we demonstrated that there is only moderate correlation between catheter angiogram Suzuki staging compared to modified Suzuki staging with MRA. In conclusion, we suggest caution in the reliance of MRA for diagnosis and follow-up of children with moyamoya. We recommend consideration catheter angiograms at time of diagnosis and with surgical planning.

High-Resolution Vessel Wall MRI of Endovascularly Treated Intracranial Aneurysms.

(1) Background: The aim of this study was to determine the frequency and the pattern of post-procedural intracranial aneurysm contrast enhancement on high-resolution vessel wall magnetic resonance imaging (HR-VW MRI). We investigated the possible association between this imaging finding and factors such as time elapsed since embolization or aneurysm occlusion grade on baseline and follow-up imaging. (2) Methods: Consecutive patients presenting for follow-up after endovascular treatment of intracranial aneurysms were included. HR-VW MRI was acquired and interpreted independently by two radiologists. (3) Results: This study included 40 aneurysms in 39 patients. Contrast enhancement was detected in 30 (75%) aneurysms. It was peripheral in 12 (30.0%), central in 9 (22.5%), and both peripheral and central in 9 (22.5%) aneurysms. The statistical analysis did not reveal any relationship between follow-up period and the presence of contrast enhancement (p = 0.277). There were no statistically significant differences in the frequency of contrast enhancement between aneurysms with total occlusion and those with remnant flow on follow-up MR angiography (p = 0.850) nor between aneurysms with different interval changes in the aneurysm occlusion grade (p = 0.536). Multivariate analysis did not demonstrate aneurysm size, ruptured aneurysm status, nor initial complete aneurysm occlusion to be a predictor of contrast enhancement (p = 0.080). (4) Conclusions: Post-procedural aneurysm contrast enhancement is a common imaging finding on HR-VW MRI. The clinical utility of this imaging finding, especially in the prediction of aneurysm recurrence, seems limited. The results of our study do not support routine use of HR-VW MRI in the follow-up of patients after endovascular treatment of intracranial aneurysms.

Time-Resolved Magnetic Resonance Angiography for Follow-Up of Treated Dural and Epidural Spinal Arteriovenous Fistula.

Spinal arteriovenous fistulas (AVFs) are uncommon vascular malformations of spinal dural and epidural vessels. Actually digital subtraction angiography (DSA) is the gold standard for diagnosis and follow-up. The aim of this study is to demonstrate the validity of the multiphasic magnetic resonance angiography (MRA) to identify recurrent/residual AVFs or their correct surgical and/or endovascular closure. A retrospective cases series with perimedullary venous plexus congestion due to spinal dural or epidural AVF was performed at our center from April 2014 to September 2019. After 1 month from treatment, the patients were subjected to time-resolved MRA and DSA to demonstrate recurrence or correct closure of AVFs. We collected a series of 26 matched time-resolved MRA and DSA in 20 patients who underwent an endovascular and/or surgical procedure. In our series, we reported five cases of recurrence. Time-resolved MRA detected six cases of recurrence, with 100% sensitivity and 95% specificity (p < 0.001). We used DSA as the standard reference. Time-resolved MRA is a valid tool in posttreatment follow-up to detect recurrent or residual AVFs. It has high sensitivity and specificity and may replace DSA.