MRA versus DSA for follow-up of coiled intracranial aneurysms: a meta-analysis

Risk factors and predictive indicators of rupture in cerebral aneurysms

Cerebral aneurysms are abnormal dilations of blood vessels in the brain that have the potential to rupture, leading to subarachnoid hemorrhage and other serious complications. Early detection and prediction of aneurysm rupture are crucial for effective management and prevention of rupture-related morbidities and mortalities. This review aims to summarize the current knowledge on risk factors and predictive indicators of rupture in cerebral aneurysms. Morphological characteristics such as aneurysm size, shape, and location, as well as hemodynamic factors including blood flow patterns and wall shear stress, have been identified as important factors influencing aneurysm stability and rupture risk. In addition to these traditional factors, emerging evidence suggests that biological and genetic factors, such as inflammation, extracellular matrix remodeling, and genetic polymorphisms, may also play significant roles in aneurysm rupture. Furthermore, advancements in computational fluid dynamics and machine learning algorithms have enabled the development of novel predictive models for rupture risk assessment. However, challenges remain in accurately predicting aneurysm rupture, and further research is needed to validate these predictors and integrate them into clinical practice. By elucidating and identifying the various risk factors and predictive indicators associated with aneurysm rupture, we can enhance personalized risk assessment and optimize treatment strategies for patients with cerebral aneurysms.

Endovascular treatment of wide-neck bifurcation aneurysms using pCONUS2 HPC bridging device with single antiplatelet: A Case Series

RATIONALE

Wide neck bifurcation aneurysms (WNBA) are technically challenging for both surgical and endovascular treatments. Endovascular treatment for WNBA often requires dual antiplatelet therapy (DAPT) post stent insertion. Novel devices such as the pCONUS2 HPC neck bridging device have an HPC coating which reduces the device thrombogenicity. This theoretically allows for use of single antiplatelet therapy (SAPT), which would be advantageous, particularly in treating ruptured aneurysms. This case series aims to evaluate the safety of SAPT regimen only post stent insertion, by presenting our center early clinical experience in using pCONUS2 HPC neck bridging device in patients that are not suitable for DAPT.

PATIENT CONCERNS

We report the cases of 3 patients (2 females, 1 male; range: 64-71 years old) who underwent coil embolization for WNBA using the pCONUS2 HPC device (2 unruptured WNBA, and 1 ruptured WNBA). As all 3 patients were allergic to Aspirin, they could only be started on SAPT post endovascular therapy.

DIAGNOSIS

All 3 patients were diagnosed with WNBA on angiographic studies. Patient 1 had an unruptured left middle cerebral artery aneurysm; Patient 2 had a ruptured basilar tip aneurysm; Patient 3 had an unruptured anterior communicating artery (ACOM) aneurysm.

INTERVENTIONS

All 3 WNBA were treated with pCONUS2 HPC neck bridging device.

OUTCOMES

There were no immediate complications. The immediate angiographic result of aneurysm treatment in Patient 1 and Patient 2 demonstrated incomplete occlusions, with delayed complete occlusion of aneurysm in Patient 1 and growth of aneurysmal neck in Patient 2 on follow-up angiograms (range: 6-9 months). No major thrombo-embolic or hemorrhagic complications in the first 2 patients. For Patient 3, the immediate angiographic result of the treated aneurysm demonstrated complete occlusion. However, the patient readmitted 11 days post procedure with cerebral infarction, scoring 5 on the modified Rankin scale on discharge.

LESSONS

pCONUS2 HPC as a neck bridging device in treating WNBA has yet to be shown superior to traditional techniques and devices. The theoretical advantage of HPC coating reducing its thrombogenicity requiring only SAPT is yet to be proven safe in clinical practice.

Imaging follow-up strategy after endovascular treatment of Intracranial aneurysms: A literature review and guideline recommendations

OBJECTIVE

Endovascular coil embolization is the primary treatment modality for intracranial aneurysms. However, its long-term durability remains of concern, with a considerable proportion of cases requiring aneurysm reopening and retreatment. Therefore, establishing optimal follow-up imaging protocols is necessary to ensure a durable occlusion. This study aimed to develop guidelines for follow-up imaging strategies after endovascular treatment of intracranial aneurysms.

METHODS

A committee comprising members of the Korean Neuroendovascular Society and other relevant societies was formed. A literature review and analyses of the major published guidelines were conducted to gather evidence. A panel of 40 experts convened to achieve a consensus on the recommendations using the modified Delphi method.

RESULTS

The panel members reached the following consensus: 1. Schedule the initial follow-up imaging within 3-6 months of treatment. 2. Noninvasive imaging modalities, such as three-dimensional time-of-flight magnetic resonance angiography (MRA) or contrast-enhanced MRA, are alternatives to digital subtraction angiography (DSA) during the first follow-up. 3. Schedule mid-term follow-up imaging at 1, 2, 4, and 6 years after the initial treatment. 4. If noninvasive imaging reveals unstable changes in the treated aneurysms, DSA should be considered. 5. Consider late-term follow-up imaging every 3-5 years for lifelong monitoring of patients with unstable changes or at high risk of recurrence.

CONCLUSIONS

The guidelines aim to provide physicians with the information to make informed decisions and provide patients with high-quality care. However, owing to a lack of specific recommendations and scientific data, these guidelines are based on expert consensus and should be considered in conjunction with individual patient characteristics and circumstances.

Extended monitoring of re-coiled cerebral aneurysms after initial postcoiling recanalization: Safety and durability of repeat coil embolization

PURPOSE

In the endovascular era, postcoiling recanalization of cerebral aneurysms is occurring with greater frequency. Repeat coiling is usually done to prevent rebleeding, although long-term outcomes of re-embolization have yet to be adequately investigated. The present study was undertaken to assess clinical and radiographic outcomes of re-embolization in recanalized aneurysms, focusing on procedural safety, efficacy, and durability.

METHOD

In this retrospective review, we examined 308 patients with 310 recurrent aneurysms. All lesions were re-coiled, once major recanalization (after initial coil embolization) was established. Medical records and radiologic data amassed during extended follow-up were then subject to review. Cox proportional hazards regression analysis was undertaken to identify risk factors for subsequent recurrence.

RESULT

During a lengthy follow-up (mean, 40.2 ± 33.0 months), major recanalization developed again in 87 aneurysms (28.1%). Multivariable Cox regression analysis linked re-recanalization to initial saccular neck width (p=.003) and autosomal dominant polycystic kidney disease (ADPKD; p<.001). Stent implantation (p=.038) and successful occlusion at second coiling (p=.012) were protective against later recanalization in this setting. The more recent the second embolization was performed, the lower the risk of further recurrence (p=.023). Procedure-related complications included asymptomatic thromboembolism (n = 9), transient ischemic neurologic deficits (n = 2), procedural bleeding (n = 1), and coil migration (n = 1), but there were no residual effects or deaths.

CONCLUSION

Repeat coil embolization is a safe therapeutic option for recanalized cerebral aneurysms. Wide-necked status and ADPKD emerged as risks for subsequent recanalization, whereas successful occlusion and stent implantation seemed to reduce the likelihood of recurrence after re-embolization procedures.

Usefulness of Pointwise Encoding Time Reduction with Radial Acquisition-Magnetic Resonance Angiography after Endovascular Treatment for Intracranial Aneurysms

PURPOSE

Imaging follow-up after endovascular treatment is important; however, time-of-flight magnetic resonance angiography (TOF-MRA) has limitations associated with magnetic susceptibility and radiofrequency shielding caused by the stent and coils. We evaluated the diagnostic performance of pointwise encoding time reduction with radial acquisition (PETRA)-MRA after endovascular treatment for intracranial aneurysms.

MATERIAL AND METHODS

A total of 186 patients with 211 aneurysms who underwent both pointwise encoding time reduction with radial acquisition- and time-of-flight magnetic resonance angiography in the same imaging session for follow-up after endovascular treatment. We subjectively graded the overall image quality, visualization of treated sites, and occlusion status.

RESULTS

Although the overall image quality scores of pointwise encoding time reduction with radial acquisition-magnetic resonance angiography were significantly lower than those of time-of-flight magnetic resonance angiography for both observers (4.04 ± 0.81 vs. 4.85 ± 0.35 [observer 1], 4.60 ± 0.69 vs. 4.94 ± 0.24 [observer 2]) (both P < .001), the visibility of treated sites using pointwise encoding time reduction with radial acquisition-magnetic resonance angiography was significantly better than that of time-of-flight magnetic resonance angiography overall (4.27 ± 0.97 vs. 3.42 ± 1.01; P < .001), in the distal internal carotid artery (4.46 ± 0.79 vs. 3.40 ± 1.00; P < .001), and in the middle cerebral artery (4.19 ± 0.93 vs. 3.08 ± 0.53, P = 0.007). Pointwise encoding time reduction with radial acquisition-magnetic resonance angiography showed a higher area under the curve than time-of-flight magnetic resonance angiography for the evaluation of treated aneurysm occlusion, except for posterior circulation aneurysms.

CONCLUSIONS

Pointwise encoding time reduction with radial acquisition-magnetic resonance angiography showed better visualization of treated sites and better diagnostic performance than time-of-flight magnetic resonance angiography for anterior circulation aneurysms. However, Pointwise encoding time reduction with radial acquisition-magnetic resonance angiography showed limitations in the follow-up evaluation of posterior circulation aneurysms.

Radiological follow-up of endovascularly treated intracranial aneurysms: a survey of current practice in the UK and Ireland

PURPOSE

Due to the risk of intracranial aneurysm (IA) recurrence and the potential requirement for re-treatment following endovascular treatment (EVT), radiological follow-up of these aneurysms is necessary. There is little evidence to guide the duration and frequency of this follow-up. The aim of this study was to establish the current practice in neurosurgical units in the UK and Ireland.

METHODS

A survey was designed with input from interventional neuroradiologists and neurosurgeons. Neurovascular consultants in each of the 30 neurosurgical units providing a neurovascular service in the UK and Ireland were contacted and asked to respond to questions regarding the follow-up practice for IA treated with EVT in their department.

RESULTS

Responses were obtained from 28/30 (94%) of departments. There was evidence of wide variations in the duration and frequency of follow-up, with a minimum follow-up duration for ruptured IA that varied from 18 months in 5/28 (18%) units to 5 years in 11/28 (39%) of units. Young patient age, previous subarachnoid haemorrhage and incomplete IA occlusion were cited as factors that would prompt more intensive surveillance, although larger and broad-necked IA were not followed-up more closely in the majority of departments.

CONCLUSIONS

There is a wide variation in the radiological follow-up of IA treated with EVT in the UK and Ireland. Further standardisation of this aspect of patient care is likely to be beneficial, but further evidence on the behaviour of IA following EVT is required in order to inform this process.

Endovascular treatment of challenging aneurysms with FRED Jr flow diverter stents: a single-center experience

PURPOSE

To analyze clinical safety and efficacy of flow re-direction endoluminal device (FRED) Jr flow diverter for treatment of unruptured, ruptured, or recanalyzed aneurysms.

MATERIALS AND METHODS

Between October 2019 and February 2022, 25 patients with 31 aneurysms treated with FRED Jr were included in the study. Clinical and radiological records, procedural details, and follow-up outcomes were retrospectively evaluated. Eighteen (72%) patients were female. Median age was 48.8 (age range 9-85). Mean follow-up was 21 months (6-28 months). Location of the aneurysms were as follows; 13 in middle cerebral artery (MCA), 7 in anterior cerebral artery (ACA), 4 in posterior cerebral artery (PCA), 3 in true posterior communicating artery (PCom), 2 in anterior communicating artery (ACom), 1 in superior cerebellar artery (SCA), 1 in true ophthalmic artery. Five patients (20%) presented with acute subarachnoid hemorrhage (aSAH).

RESULTS

In all procedures, FRED Jr was successfully deployed. Three true Pcom aneurysms and a true ophthalmic aneurysm were treated with FRED Jr. Three patients with two adjacent aneurysms were treated with a single FRED Jr. In two (8%) patients in-stent thrombosis occurred intraoperatively, they were treated with iv tirofiban and thrombectomy without any sequelae. Post-discharge 2 weeks later, intraparenchymal hemorrhage occurred in a patient. He was treated with surgical drainage, the clinical course was modified Rankin score (mRS) 2. Digital subtraction angiography (DSA) was performed on 16 (64%) patients with 21 (67%) aneurysms. Near complete-complete occlusion (O'Kelly-Morata grading scale (OKM C-D) was documented in 15/16 (93.7%) patients, 20/21 (95.2%) aneurysms. In nine (36%) patients, no residual filling was observed in the magnetic resonance angiography (MRA). Good clinical outcome (mRS 0-1) was achieved in 24/25 (96%) of patients.

CONCLUSION

Endovascular treatment of small cerebral aneurysms with FRED Jr is safe and effective even in complex and challenging morphologies allowing high rates of aneurysm occlusion with low periprocedural complications. Our cohort, consisting of a rate 20% acute ruptured aneurysms, is the major additive data to the published literature.

Follow-Up Assessment of Intracranial Aneurysms Treated with Endovascular Coiling: Comparison of Compressed Sensing and Parallel Imaging Time-of-Flight Magnetic Resonance Angiography

The aim of our study was to compare compressed sensing (CS) time-of-flight (TOF) magnetic resonance angiography (MRA) with parallel imaging (PI) TOF MRA in the evaluation of patients with intracranial aneurysms treated with coil embolization or stent-assisted coiling. We enrolled 22 patients who underwent follow-up imaging after intracranial aneurysm coil embolization. All patients underwent both PI TOF and CS TOF MRA during the same examination. Image evaluation aimed to compare the performance of CS to PI TOF MRA in determining the degree of aneurysm occlusion, as well as the depiction of parent vessel and vessels adjacent to the aneurysm dome. The reference standard for the evaluation of aneurysm occlusion was PI TOF MRA. The inter-modality agreement between CS and PI TOF MRA in the evaluation of aneurysm occlusion was almost perfect (κ  =  0.98, p  <  0.001) and the overall inter-rater agreement was substantial (κ  =  0.70, p  <  0.001). The visualization of aneurysm parent vessel in CS TOF images compared with PI TOF images was evaluated to be better in 11.4%, equal in 86.4%, and worse in 2.3%. CS TOF MRA, with almost 70% scan time reduction with respect to PI TOF MRA, yields comparable results for assessing the occlusion status of coiled intracranial aneurysms. Short scan times increase patient comfort, reduce the risk of motion artifacts, and increase patient throughput, with a resulting reduction in costs. CS TOF MRA may therefore be a potential replacement for PI TOF MRA as a first-line follow-up examination in patients with intracranial aneurysms treated with coil embolization.

Differential Subsampling with Cartesian Ordering-MRA for Classifying Residual Treated Aneurysms

BACKGROUND AND PURPOSE

Differential Subsampling with Cartesian Ordering (DISCO), an ultrafast high-spatial-resolution head MRA, has been introduced. We aimed to determine the diagnostic performance of DISCO-MRA in grading residual aneurysm in comparison with TOF-MRA in patients with treated intracranial aneurysms.

MATERIALS AND METHODS

Patients with endovascular treatment and having undergone DISCO-MRA, TOF-MRA, and DSA were included for review. The voxel size and acquisition time were 0.75 × 0.75 × 1 mm³/6 seconds for DISCO-MRA and 0.6 × 0.6 × 1 mm³/6 minutes for TOF-MRA. Residual aneurysms were determined using the Modified Raymond-Roy Classification on TOF-MRA and DISCO-MRA by 2 neuroradiologists independently and were compared against DSA as the reference standard. Statistical analysis was performed using the κ statistic and the χ² test.

RESULTS

Sixty-eight treated intracranial aneurysms were included. The intermodality agreement was κ = 0.82 (95% CI, 0.67-0.97) between DISCO and DSA and 0.44 (95% CI, 0.28-0.61) between TOF and DSA. Modified Raymond-Roy Classification scores matched DSA scores in 60/68 cases (88%; χ² = 144.4, P < .001 for DISCO and 46/68 cases (68%; χ² = 65.0, P < .001) for TOF. The diagnostic accuracy for the detection of aneurysm remnants was higher for DISCO (0.96; 95% CI, 0.88-0.99) than for TOF (0.79; 95% CI, 0.68-0.88).

CONCLUSIONS

In patients with endovascularly treated intracranial aneurysms, DISCO-MRA provides superior diagnostic performance in comparison with TOF-MRA in delineating residual aneurysms in a fraction of the time.

Long-term outcomes of Y-stent-assisted coil embolization using Low-profile Visualized Intraluminal Support Junior (LVIS Jr) for intracranial bifurcation aneurysms

OBJECTIVE

Y-stent-assisted coil embolization is indicated for the treatment of complex intracranial bifurcation aneurysms. However, the long-term outcomes associated with this technique remain unclear. The purpose of this study was to evaluate the long-term outcomes of Y-stent-assisted coil embolization using the Low-profile Visualized Intraluminal Support Junior (LVIS Jr) device.

METHODS

We retrospectively reviewed our databases to identify patients treated with Y-stent-assisted coiling using LVIS Jr. Digital subtraction angiography, silent magnetic resonance angiography (MRA), and time-of-flight MRA were performed at 1 year after the procedure. Patients also received an annual follow-up using MRA. Aneurysm occlusion status was classified into complete occlusion (CO), neck remnant (NR), and body filling (BF). Clinical outcomes were assessed using the modified Rankin Scale.

RESULTS

Twenty-one patients (22 aneurysms) were included in this study. All procedures were performed successfully. Immediate postprocedural angiograms showed CO in 13 aneurysms (59.1%), NR in two aneurysms (9.1%), and BF in seven aneurysms (31.8%). One-year follow-up angiograms revealed CO in 86.4% of patients. Only one patient had a major recurrence and required retreatment. The mean follow-up duration was 43.5 months. The last angiographic studies demonstrated CO in 18 aneurysms (81.8%), NR in three aneurysms (13.6%), and BF in one aneurysm (4.5%). Periprocedural and delayed complications occurred in two patients and one patient, respectively. There was no permanent morbidity or death. The modified Rankin Scale scores at last clinical follow-up were equal to those before the procedures in all patients.

CONCLUSION

Y-stent-assisted coil embolization using LVIS Jr for intracranial bifurcation aneurysms has favorable long-term angiographic and clinical outcomes.

Intensity of arterial structure acquired by Silent MRA estimates cerebral blood flow

BACKGROUND

Cerebral blood flow (CBF) and the morphology of the cerebral arteries are important for characterizing cerebrovascular disease. Silent magnetic resonance angiography (Silent MRA) is a MRA technique focusing on arterial structural delineation. This study was conducted to investigate the correlation between Silent MRA and CBF quantification, which has not yet been reported.

METHODS

Both the Silent MRA and time-of-flight magnetic resonance angiography scans were applied in seventeen healthy participants to acquire the arterial structure and to find arterial intensities. Phase-contrast MRA (PC-MRA) was then used to perform the quantitative CBF measurement of 13 cerebral arteries. Due to different dataset baseline signal level of Silent MRA, the signal intensities of the selected 13 cerebral arteries were normalized to the selected ROIs of bilateral internal carotid arteries. The normalized signal intensities were used to determine the relationship between Silent MRA and CBF.

RESULTS

The image intensity distribution of arterial regions generated by Silent MRA showed similar laminar shape as the phase distribution by PC-MRA (correlation coefficient > 0.62). Moreover, in both the results of individual and group-leveled analysis, the intensity value of arterial regions by Silent MRA showed positively correlation with the CBF by PC-MRA. The coefficient of determination (R²) of individual trends ranged from 0.242 to 0.956, and the R² of group-leveled result was 0.550.

CONCLUSIONS

This study demonstrates that Silent MRA provides valuable CBF information despite arterial structure, rendering it a potential tool for screening for cerebrovascular disease.

Usefulness of Craniograms in Discriminating Coiled Intracranial Aneurysms Requiring Retreatment

While endovascular coil embolization has become one of the major therapeutic modalities for intracranial aneurysms, long-term imaging follow-up is required because of the higher rate of retreatment compared with surgical clipping. The purpose of this study was to show the usefulness of craniograms to discriminate coiled intracranial aneurysms that required retreatment. Under the study protocol approved by institutional review board, a retrospective review of the medical record was done regarding coil embolization for intracranial aneurysms performed between January 2014 and December 2018. Coil embolization performed as the initial treatment and followed up for more than 1 year without additional treatment, and those performed as retreatment after the initial coil embolization performed at our institution were recruited. Craniograms obtained just after the initial treatment were compared with those obtained just before the additional treatment in the retreated cases and compared with the latest ones in the non-recurrence cases. Correlation between the morphological changes in the coil mass on the craniograms and retreatments was evaluated. During the study period, 288 coil embolization procedures for intracranial aneurysms were performed. From these, 191 treatments that were followed up for more than 1 year without any additional treatments and 30 retreatments were included. Morphological change of the coil mass was observed in 4 of the 191 non-recurrence treatments and 26 of the 30 retreatments, which was significantly correlated with retreatments (p <0.001). Craniogram was a useful modality in following up the coiled intracranial aneurysms to detect those required retreatments.

Usefulness of contrast-enhanced 3D MR angiography and contrast-enhanced 3D T1 sequence for detecting intracranial infectious aneurysms in infectious endocarditis

OBJECTIVES

To assess the diagnostic value of contrast-enhanced MRA (CE MRA) and CE 3D-T1 for identifying intracranial infectious aneurysms (IIAs) in infective endocarditis (IE) with digital substraction angiography (DSA) as reference.

METHODS

Twenty-one IE patients (14 males; mean age: 53 years) with 30 IIAs, diameter ranging 1.5-15 mm (<3mm, n = 14, 46.7%; 3-5 mm, n = 12,40%), underwent CE MRA and CE 3D-T1 at 1.5 T. Two readers evaluated images for aneurysm detection, characterization, quality of visualization. DSA was obtained at a median of 3 days (range 1-15) after MRI.

RESULTS

The sensitivity, specificity, positive and negative predictive values and accuracy of IIA detection were respectively: 80%, 100%, 100%, 82.3%, 90% for CE MRA and 86.7%, 100%, 100%, 88.2%, 93.3% for CE 3D T1 compared to DSA. No significant difference was observed between CE MRA and CE 3D-T1 for accuracy and quality of visualization. All IIAs of ≥3 mm in diameter (16/30; 53.%) were identified by both sequences, which were also able to detect IIAs ≤ 3 mm (n = 14/30, 46.7%). False negatives were observed with both sequences for 4 IIAs of <2 mm, 3 being compressed by hemorrhagic lesions. Two other IIAs of <2 mm were overlooked by CE MRA. CE 3D-T1 overestimated IIAs luminal diameter by 8% relatively to DSA (P = NS). Intra and inter-observer agreement were good and similar with both methods.

CONCLUSION

Both CE MRA and CE 3D-T1 have good accuracy compared to DSA detection and characterization of IIAs. CE 3D-T1 also evaluates anatomical relationships of IIAs, which could help DSA location and endovascular treatment.

ACR Appropriateness Criteria® Cerebrovascular Diseases-Aneurysm, Vascular Malformation, and Subarachnoid Hemorrhage

Cerebrovascular disease is a broad topic. This document focuses on the imaging recommendations for the varied clinical scenarios involving intracranial aneurysms, vascular malformations, and vasculitis, which all carry high risk of morbidity and mortality. Additional imaging recommendations regarding complications of these conditions, including subarachnoid hemorrhage and vasospasm, are also covered. While each variant presentation has unique imaging recommendations, the major focus of this document is neurovascular imaging techniques. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Midterm Outcomes After Low-Profile Visualization Endoluminal Support or Atlas Stent-Assisted Coiling of Intracranial Aneurysms: A Propensity Score Matching Analysis

BACKGROUND

The interplay of various commercially available stents during coil embolization of intracranial aneurysms and their ultimate impact are subject to debate.

OBJECTIVE

To compare midterm outcomes of Low-Profile Visualization Endoluminal Support (LVIS) (MicroVention Inc) and Atlas (Stryker) stent-assisted coiling procedures.

METHODS

A total of 459 intracranial aneurysms subjected to coil embolization using LVIS (n = 318) or Atlas stents (n = 141) between April 2015 and December 2019 were eligible for study. To assess occlusive status postembolization, magnetic resonance angiography and/or conventional angiography were used. The Raymond classification was applied to categorize recanalization. Our analysis was propensity score matched according to probability of stent type deployed.

RESULTS

Eventually, 41 aneurysms (8.9%) displayed recanalization (minor, 28; major, 13) 6 mo after coiling. Patient age (P = .018), sex (P = .015), aneurysmal location (P < .001), and type of aneurysm (P < .001) differed significantly by group. Overall and major recanalization rates at midterm were similar in both groups (9.1% and 8.5% vs 3.1% and 2.1%, respectively), and there was no significant difference even after 1:1 propensity score matching (odds ratio [OR] = 0.75 [P = .514] and OR = 0.75 [P = .706], respectively).

CONCLUSION

In stent-assisted coil embolization of intracranial aneurysms, midterm outcomes of LVIS and Atlas device groups were similar, despite theoretic LVIS superiority. Further randomized comparative studies are needed to confirm our findings.

Noninvasive Angiographic Results of Clipped or Coiled Intracranial Aneurysms: An Inter- and Intraobserver Reliability Study

BACKGROUND AND PURPOSE

Noninvasive angiography is commonly used to assess the outcome of surgical or endovascular treatment of intracranial aneurysms in clinical series or randomized trials. We sought to assess whether a standardized 3-grade classification system could be reliably used to compare the CTA and MRA results of both treatments.

MATERIALS AND METHODS

An electronic portfolio composed of CTAs of 30 clipped and MRAs of 30 coiled aneurysms was independently evaluated by 24 raters of diverse experience and training backgrounds. Twenty raters performed a second evaluation 1 month later. Raters were asked which angiographic grade and management decision (retreatment; close or long-term follow-up) would be most appropriate for each case. Agreement was analyzed using the Krippendorff α (α_K) statistic, and the relationship between angiographic grade and clinical management choice, using the Fisher exact and Cramer V tests.

RESULTS

Interrater agreement was substantial (α_K = 0.63; 95% CI, 0.55-0.70); results were slightly better for MRA results of coiling (α_K = 0.69; 95% CI, 0.56-0.76) than for CTA results of clipping (α_K = 0.58; 95% CI, 0.44-0.69). Intrarater agreement was substantial to almost perfect. Interrater agreement regarding clinical management was moderate for both clipped (α_K = 0.49; 95% CI, 0.32-0.61) and coiled subgroups (α_K = 0.47; 95% CI, 0.34-0.54). The choice of clinical management was strongly associated with the size of the residuum (mean Cramer V = 0.77 [SD, 0.14]), but complete occlusions (grade 1) were followed more closely after coiling than after clipping (P = .01).

CONCLUSIONS

A standardized 3-grade scale was found to be a reliable and clinically meaningful tool to compare the results of clipping and coiling of aneurysms using CTA or MRA.

Evaluation of the Safety and Effectiveness of Coil Embolization for Anterior Communicating and Anterior Cerebral Artery Aneurysms

Objective

Endovascular coil embolization for anterior communicating artery (ACoA) and anterior cerebral artery (ACA) aneurysms is associated with high total and near-total occlusion rates, but the complication rate is high. The development of newer endovascular technologies may improve the clinical outcomes. This study investigated the status of endovascular treatment of ACoA and ACA aneurysms by comparing our results with past reports.

Methods

Between January 2006 and December 2018, we investigated 50 patients who were followed for 12 months or longer to clarify the outcomes of coil embolization. The outcomes of embolization were evaluated using time-of-flight MRA. The safety was evaluated based on procedure-related complications that affected clinical outcomes.

Results

Initial assessments demonstrated complete obliteration in 84% (42 of 50 patients) and a residual neck in 14% (7 of 50 patients). Procedure-related complications developed in 12% (6 of 50 patients). The procedure-related morbidity rate was 2% (1 of 50 patients) and there was no procedure-related death. Recanalization was noted in 14% (7 of 50 patients, median follow-up period, 57 months). The recanalized aneurysms were significantly smaller than the stable aneurysms in maximum size (4.3 mm vs. 5.8 mm; p = 0.017) and height (3.7 mm vs. 4.3 mm; p = 0.035).

Conclusion

We demonstrated the safety and effectiveness of endovascular coil embolization for ACoA and ACA aneurysms. The small size of aneurysms may be related to recanalization.

Application of 3D T1-SPACE combined with 3D-TOF sequence for follow-up evaluation of stent-assisted coil embolization for intracranial aneurysm

OBJECTIVES

To assess 3D T1-SPACE combined with 3D-TOF sequence for follow-up evaluation of stent-assisted coil embolization for intracranial aneurysm.

MATERIALS AND METHODS

Between Oct 2018 and May 2019, we enrolled 25 patients with intracranial aneurysm who underwent stent-assisted coil embolization. All patients were followed up for 6 to10 months after endovascular treatment (EVT) using 3D-TOF MRA, 3D T1-SPACE and DSA to evaluate aneurysm occlusion and parent artery patency.

RESULTS

With regards to aneurysm occlusion, the specificity of 3D-TOF MRA was 86.9% (20/23) and the accuracy was 84% (21/25). There was no statistical significance (P ​= ​0.409) compared with the DSA. The parent artery by 3D-TOF MRA showed that there were 14 patients with grade 3, 8 patients with grade 2 and 3 patients with grade 1. However, 3D T1-SPACE showed that all 25 patients were grade 4, and were clearly displayed without metal artifacts. The comparison of the two MR techniques demonstrated that 3D T1-SPACE was superior to 3D-TOF MRA in the evaluation of parent artery (P<0.001).

CONCLUSIONS

3D T1-SPACE sequence provides better image quality and higher accuracy for evaluating stented parent arteries compared to TOF-MRA. This study also shows that 3D-TOF MRA has a merit to evaluate aneurysm occlusion. The combination of these two modalities can be used as an optional follow-up evaluation after EVT of intracranial aneurysms.

Knowledge framework and emerging trends in intracranial aneurysm magnetic resonance angiography: a scientometric analysis from 2004 to 2020

Background

As magnetic resonance angiography (MRA) has been increasingly used in the follow-up of intracranial aneurysms (IAs) as a non-invasive technique, the knowledge framework and areas of research interest in intracranial aneurysms magnetic resonance angiography (IAMRA) change approximately every 10 years. However, few studies have quantitatively analyzed the published literature in this field. In the present study, we used scientometrics to survey the knowledge field, development trends, and research focus of IAMRA with the aim of providing a reference for further study.

Methods

We collected articles on IAMRA published from 2004 (Jan 1, 2004) to 2020 (May 24, 2020). Web of Science Core Collection databases (WoSCCd) including the Science Citation Index Expanded were searched. An experienced staff member from the Department of Radiology at Southern Medical University, assisted in screening articles for relevant articles. We used ArcGIS (a mapping and location analytics platform) to perform geographic visualization. Excel 2016 was used to analyze the literature data, including number of publications, impact factor (IF), and publication year. CiteSpace V was used to conduct a series of literature feature clustering, including author co-citation analysis, reference co-citation analysis (RCA), and burst keywords analysis.

Results

A total of 1,272 articles on IAMRA published between 2004 and 2020 were included. Of 257 journals, American Journal of Neuroradiology (IF 2018: 3.256) published the most IAMRA articles (109 publications, 8.57%), followed by Journal of Neurosurgery (IF 2018: 4.131, 51 publications, 4.16%), and Neuroradiology (IF 2018: 2.504, 51 publications, 4.01%). Of 56 countries, the USA published the most, with 347 articles [27.28%, IF: 3.14 (average IF of all journals in the country)], followed by Japan (242 articles, 19.03%, IF: 2.38), Germany (135 articles, 10.61%, IF: 3.21), and China (101 articles, 7.94%, IF: 2.86). A total of 1387 institutions published articles, with the Mayo Clinic publishing the most (33 articles, 2.59%), followed by Shanghai Jiao Tong University (25 article, 1.97%), Seoul National University (23 articles, 1.81%), and University Medical Center Utrecht (19 articles, 1.49%). Of 399 authors, Rinkel ranked first with 19 articles, followed by Li MH (18 articles), Uchino A (15 articles), and Saito N (13 articles). Cluster RCA showed that the first cluster was "#0 growth", followed by "#1 Guglielmi detachable coils". Timeline views showed that the time span of "#0 growth" was the closest to today. The modularity value was 0.6971, and the mean silhouette value was 0.5477. According to the burst keyword analysis, "risk factors associated to rupture" was the topic with the strongest burst since 2017. Studies conducted in several countries suggested that age is inversely related to the risk of rupture, which implies the importance of MRA follow-up for patients of different age.

Conclusions

From 2004 to 2020, the number of published IAMRA-related articles gradually increased. The USA and Western Europe lead in the field, with a concentration of cutting-edge talents and high-level scientific research institutions. A synthesis of the clustering results of RCA and burst keyword analysis indicated that unruptured IA growth, stent-assisted coil embolization, and risk factors associated to rupture were the current hotspots in IAMRA research.

Utility of skull X-rays in identifying recurrence of coiled cerebral aneurysms

OBJECTIVE

A high rate of cerebral aneurysm recurrence following endovascular coiling has prompted the use of digital subtraction angiography (DSA) for interval follow-up. However, the utility of skull x-rays as an alternative screening method for aneurysm recurrence is unproperly characterized.

METHODS

Retrospective review of a prospective registry of ruptured and unruptured cerebral aneurysms. Anteroposterior and lateral skull x-rays were obtained immediately at the end of the procedure and at 6-month follow-up. Aneurysm recurrence was defined by comparing post-procedure and 6-month DSA imaging. A true positive was defined as a change in coil mass morphology on at least one projection with aneurysm recurrence on DSA, and a true negative defined as a stable coil mass on both projections and no recurrence on DSA. Receiver operating characteristic area under the curve (AUC) statistics was used to assess the performance of skull x-rays in identifying aneurysm recurrence.

RESULTS

A total of 118 cerebral aneurysms were evaluated with DSA imaging and skull x-rays. A change in coil mass morphology on one projection of skull x-rays correctly detected all true recurrences with a sensitivity of 100% (95% confidence interval [CI], 91-100%). Skull x-rays failed to identify a stable aneurysm coil mass in 15 cases, with a specificity of 79% (68-88%). Skull x-rays performed with AUC 0.8958 (95% CI, 0.8490-0.9431) in identifying aneurysm recurrence.

CONCLUSIONS

The findings of our study suggest that skull x-rays may represent a lowcost, non-invasive screening tool to rule out aneurysm recurrence, which can potentially aid in decreasing the utilization of DSA in the follow-up of patients with coiled cerebral aneurysms.

Early Post-operative CT-Angiography Imaging After EC-IC Bypass Surgery in Moyamoya Patients

Objective: To evaluate the clinical value of early post-operative computed tomographic angiography (CTA) after direct extracranial-intracranial (EC-IC) bypass surgery in moyamoya patients. Methods: A retrospective analysis of all adult moyamoya patients treated at our center from 2013 to 2019 with a direct EC-IC bypass was performed. Early post-operative CTA (within 24 h after surgery) was compared with conventional digital subtraction angiography (DSA) 6-12 months after surgery. If available, magnetic resonance time-of-flight angiography (MR-TOF) was evaluated 3 months and 6-12 months post-operatively as well. Imaging results were analyzed and compared with CTA, MR-TOF and DSA, whereat DSA was used as the final and definite modality to decide on bypass patency. Results: A total of 103 direct EC-IC bypasses in 63 moyamoya patients were analyzed. All inclusion criteria were met in 32 patients (53 direct bypasses). In 84.9% the bypass appeared definitively, in 5.7% uncertainly and in 9.4% not patent according to early post-operative CTA. MR-TOF suggested definitive bypass patency in 86.8% 3 months after surgery and in 93.5% 6-12 months after surgery. DSA 6-12 months post-operatively showed a patency in 98.1% of all bypasses. The positive predictive value (to correctly detect an occluded bypass) on post-operative CTA was 12.5%, the negative predictive value (to correctly detect a patent bypass) was 100% with a sensitivity of 100% and a specificity of 86.5%. Conclusion: Early post-operative CTA has a high predictive value to confirm the patency of a bypass. On the other hand, a high false positive rate of (according to CTA) occluded bypasses after direct EC-IC bypass surgery can be seen. This must be considered critically when initiating possible therapeutic measures.

The sensitivity and specificity of TOF-MRA compared with DSA in the follow-up of treated intracranial aneurysms

BACKGROUND

Time-of-flight magnetic resonance angiography (TOF-MRA) is widely used in detecting intracranial aneurysms (IA), but it is limited and controversial for use during follow-up to assess the outcome of interventional coiling or clipping surgery.

METHODS

To evaluate the specificity and sensitivity of using TOF-MRA as an imaging follow-up for IA with different treatments. A total of 280 patients with 326 treated IA underwent simultaneous TOF-MRA and digital subtraction angiography (DSA) as follow-up imaging on the same day. All images were independently reviewed by two neurosurgeons and two radiologists. The consensus evaluation of intra-arterial DSA as a reference test was used to evaluate the result of aneurysm occlusions. The aneurysmal embolization status was assessed with two ratings involving complete or incomplete occlusions. We calculated the sensitivity, specificity, negative predictive value, and positive predictive value of three-dimensional-TOF-MRA to investigate the diagnostic performance.

RESULTS

Overall sensitivity and specificity of TOF-MRA for diagnosing the remnant were 83.3% and 95.2%, respectively. The sensitivity and specificity of interventional therapy was 90.0% and 94.2%, respectively, while the clipping group showed sensitivity and specificity of 50.0% and 100%, respectively. For additional groups, involving coil only, stent-assisted, and flow diverter, the analysis of interventional therapy showed sensitivities and specificities of 100.0% and 90.1%, 66.7% and 95.1%, and 91.7% and 100%, respectively.

CONCLUSIONS

TOF-MRA can be used as a first-line noninvasive imaging modality during follow-up, especially for the patients treated with a pipeline embolization device and coils only. But it may not be enough for clipped aneurysms.

Noncontrast Magnetic Resonance Angiography in the Era of Nephrogenic Systemic Fibrosis and Gadolinium Deposition

ABSTRACT

Gadolinium-based contrast agents for clinical magnetic resonance imaging are overall safe. However, the discovery of nephrogenic systemic fibrosis in patients with severe renal impairment and gadolinium deposition in patients receiving contrast have generated developments in contrast-free imaging of the vasculature, that is, noncontrast magnetic resonance angiography. This article presents an update on noncontrast magnetic resonance angiography techniques, with comparison to other imaging alternatives. Potential benefits and challenges to implementation, and evidence to date for various clinical applications are discussed.

Neurovascular disease, diagnosis, and therapy: Subarachnoid hemorrhage and cerebral vasospasm

The worldwide incidence of spontaneous subarachnoid hemorrhage is about 6.1 per 100,000 cases per year (Etminan et al., 2019). Eighty-five percent of cases are due to intracranial aneurysms. The mean age of those affected is 55 years, and two-thirds of the patients are female. The prognosis is related mainly to the neurologic condition after the subarachnoid hemorrhage and the age of the patient. Overall, 15% of patients die before reaching the hospital, another 20% die within 30 days, and overall 75% are dead or remain disabled. Case fatality has declined by 17% over the last 3 decades. Despite the improvement in outcome probably due to improved diagnosis, early aneurysm repair, administration of nimodipine, and advanced intensive care support, the outcome is not very good. Even among survivors, 75% have permanent cognitive deficits, mood disorders, fatigue, inability to return to work, and executive dysfunction and are often unable to return to their premorbid level of functioning. The key diagnostic test is computed tomography, and the treatments that are most strongly supported by scientific evidence are to undertake aneurysm repair in a timely fashion by endovascular coiling rather than neurosurgical clipping when feasible and to administer enteral nimodipine. The most common complications are aneurysm rebleeding, hydrocephalus, delayed cerebral ischemia, and medical complications (fever, anemia, and hyperglycemia). Management also probably is optimized by neurologic intensive care units and multidisciplinary teams.

Usefulness of 3D T1-SPACE in Combination With 3D-TOF MRA for Follow-Up Evaluation of Intracranial Aneurysms Treated With Pipeline Embolization Devices

Object: Follow-up evaluation of intracranial aneurysms treated by flow-diverting stents using MRI is challenging due to the presence of imaging artifacts. This study evaluated 3D T1-SPACE in combination with 3D-TOF sequence for follow-up evaluation of intracranial aneurysms treated with Pipeline embolization devices.

Methods: Forty patients with 53 intracranial aneurysms who were treated with Pipeline Embolization Devices from October 2018 to July 2019 were enrolled in this study. All patients were evaluated for aneurysm occlusion and stent patency 4 to 7 months post-treatment using 3D T1-SPACE sequence, 3D-TOF MRA, and DSA examinations.

Results: With regards to aneurysm occlusion, the intermodality (DSA and 3D-TOF MRA) agreement was good (κ = 0.755). The specificity of 3D-TOF MRA was 94.4% (34/36), the sensitivity was 76.5% (13/17), the total coincidence rate was 88.7% (47/53). With regards to the patency of the stented arteries after PED treatment, 3D T1-SPACE sequence was more accurate compared to 3D-TOF MRA (Z = −6.283, P < 0.001), with a no-artifact rate of 95.7% (44/46).

Conclusions: 3D T1-SPACE sequence provides better image quality and higher accuracy for evaluating stented parent arteries compared to TOF-MRA. 3D-TOF MRA may be valuable in the evaluation of aneurysm occlusion. The combination of these two modalities may be used for long-term follow-up of intracranial aneurysms treated with Pipeline Embolization Devices.

A single-centre experience and literature review of Flow Re-Directional Endoluminal Device (FRED) in endovascular treatment of intracranial aneurysms

AIM

To present initial single-centre experience with the Flow Re-Direction Endoluminal Device, FRED.

MATERIALS AND METHODS

This was a retrospective study. All patients treated with FRED from October 2015 to April 2017 were included in the study. Details of the aneurysms, complications as well as follow-up results were recorded. A PubMed search was performed using the keywords "Flow Re-Direction Endoluminal Device", "FRED", "flow diverter", "FD", "FD Stent", "flow re-direction" and "flow redirection" and the results were reviewed and compared to the present authors.

RESULTS

A total of 21 patients with 25 aneurysms were analysed. No patient was lost to follow-up. At 6 months follow-up, 17 aneurysms (68%) were completely occluded, five had reduced flow, two had persistent flow and the remaining one showed increased flow. Two aneurysms from the reduced flow at 6 months had achieved complete occlusion at 1 year, raising the complete occlusion rate to 76%. Overall, 22/25 (88%) aneurysms were either occluded completely or had reduced flow at 1 year. The appearances of the other aneurysms were stable in subsequent follow-ups. Three complications were recorded (one haemorrhagic, two occlusive/thromboembolic). There was no mortality in the present study. The occlusion rate at University Hospital of Wales as well as the complication rate was comparable to other centres on published data.

CONCLUSION

FRED is a safe and effective flow diverter, which can be used to treat complex aneurysms that would have been of higher risk and for which for conventional coiling would be ineffective or unsuitable.

The clinical value of ceMRA versus DSA for follow-up of intracranial aneurysms treated by coil embolization: an assessment of occlusion classifications and impact on treatment decisions

OBJECTIVE

The aim of this study was a detailed analysis of the value of contrast-enhanced magnetic resonance angiography (ceMRA) compared to digital subtraction angiography (DSA) for follow-up imaging of intracranial aneurysms treated by coil embolization.

METHODS

Patients with coiled aneurysms and follow-up exams including both DSA and 3 T ceMRA were retrospectively identified. In blinded readings, both modalities were graded according to the modified Raymond-Roy classification (MRRC) and the Meyers scale. Additionally, readers were asked to make a decision regarding retreatment/follow-up based on the respective imaging findings.

RESULTS

The study comprised 92 patients harboring 102 coiled aneurysms. There was good intermethod agreement of DSA and ceMRA concerning both the MRRC (κ = 0.64) and the Meyers scale (κ = 0.74). Agreement regarding occlusion of < 90% of the aneurysm (Meyers grade ≥ 2) was very good (κ = 0.87). Regarding the detection of a remnant with contrast between the coil mass and the aneurysm wall (MRRC IIIb), there were 12 discrepant findings and agreement was good (κ = 0.70). Comparing treatment/follow-up decisions, the two methods agreed very well (κ = 0.92). In seven patients with discrepant treatment decisions, the authors concurred with DSA in four cases and with ceMRA in three cases when evaluating both modalities together. Interval aneurysm growth was found in more cases with ceMRA (n = 19) than with DSA (n = 16).

CONCLUSIONS

CeMRA is very unlikely to miss a relevant aneurysm remnant and thus could be suitable as the primary follow-up method. In case of remnant growth or recurrence, however, additional DSA might be required to guide treatment decisions.

KEY POINTS

• There is high accordance between ceMRA and DSA regarding the evaluation of intracranial aneurysms treated by endovascular coil embolization, but closer analysis also revealed relevant differences. • CeMRA could be suitable as the primary follow-up imaging modality, potentially eliminating the need for routine DSA. • DSA will still be required in case of aneurysm remnant growth or recurrence as detected by ceMRA.

Stent-Assisted Coiling of Unruptured MCA Aneurysms Using the LVIS Jr. Device: A Multicenter Registry

Purpose: The low-profile visualized intraluminal support junior (LVIS Jr.) is a new generation low-profile braided stent. Our aim was to evaluate the safety and efficacy of the LVIS Jr. in the stent-assisted coiling of unruptured middle cerebral artery (MCA) aneurysms. This was a multicenter retrospective study. Patient demographics, aneurysm characteristics, procedural details, complications, and the results of clinical and imaging follow-up were analyzed. Four centers participated in the study. A total of 162 consecutive patients with 162 unruptured MCA aneurysms were included for the analysis. The mean aneurysm size was 7.6 mm (range 2 to 37 mm) and 97.5% were wide-necked. Immediate postprocedural angiograms showed Raymond-Roy class 1 in 118 (72.8%), class 2 in 23 (14.2%), and class 3 in 21 patients (13%). Periprocedural complications occurred in 14 patients (8.6%). There were no procedure-related deaths. Follow-up imaging at 12–18 months post-procedure showed Raymond–Roy class 1 in 132 (81.5%), class 2 in 17 (10.5%), and class 3 in 13 patients (8%). There were 3 cases of in-stent stenosis (1.9%). All 162 patients had good clinical outcome (mRS score 0–2) at 90 days post-procedure. Stent-assisted coiling of unruptured MCA aneurysms with the LVIS Jr. stent is safe and effective, with high immediate and long-term total occlusion rates.

Prediction of internal carotid artery aneurysm recurrence by pressure difference at the coil mass surface

PURPOSE

A previous study on computational fluid dynamics reported that a high pressure difference (PD) at the surface of a coil mass is a strong predictor of aneurysm recurrence after coil embolization. PD was calculated using a virtual post-coiling model (VM), created by manually cutting the aneurysm by the flat plane from an anatomic model created with pre-coil embolization data; however, its credibility has not been fully evaluated. This study aims to clarify whether PD values calculated using the post-coiling model, which reflects the actual coil plane, are a strong predictor of aneurysm recurrence.

METHODS

Fifty internal carotid artery aneurysms treated with endovascular coil embolization were analyzed (7 recanalized, 43 stable). We created and subjected two post-coiling models, namely, VM and the real post-coiling model (RM), constructed from the post-coil embolization data. The relationship between PD and aneurysm recurrence was examined using these models. PD and its constituent three parameters were compared between VM and RM.

RESULTS

PD values calculated using RM showed significantly higher aneurysm recurrence in recurrence group than stable group (p < 0.001), and multivariate analysis showed that PD in RM (p = 0.02; odds ratio, 36.24) was significantly associated with aneurysm recurrence. The receiver operating characteristic analysis revealed that PD values accurately predicted aneurysm recurrence (area under the curve, 0.977; cutoff value, 3.08; sensitivity, 100%; specificity, 97.7%). All four parameters showed a significant correlation with VM and RM (p < 0.001).

CONCLUSION

Use of PD to predict recurrence after coil embolization can be clinically relevant.

Is 3 years adequate for tracking completely occluded coiled aneurysms?

OBJECTIVE

The authors conducted a study to ascertain the long-term durability of coiled aneurysms completely occluded at 36 months' follow-up given the potential for delayed recanalization.

METHODS

In this retrospective review, the authors examined 299 patients with 339 aneurysms, all shown to be completely occluded at 36 months on follow-up images obtained between 2011 and 2013. Medical records and radiological data acquired during the extended monitoring period (mean 74.3 ± 22.5 months) were retrieved, and the authors analyzed the incidence of (including mean annual risk) and risk factors for delayed recanalization.

RESULTS

A total of 5 coiled aneurysms (1.5%) occluded completely at 36 months showed recanalization (0.46% per aneurysm-year) during the long-term surveillance period (1081.9 aneurysm-years), 2 surfacing within 60 months and 3 developing thereafter. Four showed minor recanalization, with only one instance of major recanalization. The latter involved the posterior communicating artery as an apparent de novo lesion, arising at the neck of a firmly coiled sac, and was unrelated to coil compaction or growth. Additional embolization was undertaken. In a multivariate analysis, a second embolization for a recurrent aneurysm (HR = 22.088, p = 0.003) independently correlated with delayed recanalization.

CONCLUSIONS

Almost all coiled aneurysms (98.5%) showing complete occlusion at 36 months postembolization proved to be stable during extended observation. However, recurrent aneurysms were predisposed to delayed recanalization. Given the low probability yet seriousness of delayed recanalization and the possibility of de novo aneurysm formation, careful monitoring may be still considered in this setting but at less frequent intervals beyond 36 months.

Follow-up outcomes of intracranial aneurysms treated using braided or laser-cut stents with closed-cell design: a propensity score-matched case-controlled comparison

BACKGROUND

The impact of various stents on patients with intracranial aneurysms who undergo stent-assisted coiling has been debated. We conducted this study to compare follow-up outcomes of coiling procedures involving braided or laser-cut stents with closed-cell design. A propensity score-matched case-controlled analysis was applied.

METHODS

A total of 413 intracranial aneurysms consecutively coiled using laser-cut (n=245) or braided stents (n=168) in procedures performed between September 2012 and June 2017 were eligible for study. Time-of-flight magnetic resonance angiography, catheter angiography, or both were used to gauge occlusive status after coiling. Recanalization was determined by Raymond classification (complete occlusion vs recanalization). A propensity score-matched analysis was conducted, based on probability of stent type in use.

RESULTS

Ultimately, 93 coiled aneurysms (22.5%) showed some recanalization (minor, 51; major, 42) during the follow-up period (mean 21.7±14.5 months). Patient gender (P=0.042), hyperlipidemia (P=0.015), size of aneurysm (P=0.004), neck size (P<0.001), type of aneurysm (P<0.001), and packing density (P=0.024) differed significantly by group. Midterm and cumulative recanalization incidence rates in the braided-stent group were initially lower than those of the laser-cut stent group (P=0.009 and P=0.037, respectively) but they did not differ significantly after 1:1 propensity score matching (midterm OR=0.88, P=0.724; cumulative HR=0.91, P=0.758).

CONCLUSION

In stent-assisted coiling of intracranial aneurysms, laser-cut and braided stent groups produced similar outcomes in follow-up. Consequently, product selection may hinge on suitability for deployment rather than anticipated results.

Follow-up non-contrast MRA after treatment of intracranial aneurysms using microcoils with prominent metallic artifact: a comparative study of TOF-MRA and Silent MRA

PURPOSE

Some of the detachable microcoils are associated with the prominent metallic artifact. We have applied Silent MRA to reduce the artifact. In this study, we present a retrospective study in which Silent MRA is used for cases showing prominent metallic artifact on conventional TOF-MRA due to a detachable bare platinum microcoil (Barricade coil).

MATERIALS AND METHODS

Fifteen patients, who had undergone endosaccular embolization using Barricade coil and other detachable microcoils up to 3 days previously, were scanned with TOF-MRA and silent MRA at the same time. The treatment DSA and follow-up MRA images were graded by two experienced neuroradiologists, focusing on the visibility of residual aneurysm and parent arterial lumen.

RESULTS

DSA images showed residual aneurysm (RA) in four, residual neck (RN) in six, and complete occlusion (CO) in five patients. TOF-MRA images showed RN in five, CO in four, mild defect (MD) in one, severe defect (SD) in three, and complete defect in two. In contrast, on Silent MRA, the grades were RA in two, RN in five, CO in five, and MD in three.

CONCLUSION

Barricade coils are associated with prominent metallic artifact on TOF-MRA. Silent MRA is useful for follow-up MRA after embolization using Barricade coils. The metallic artifacts were compared between TOF-MRA and Silent MRA in patients treated by using Barricade coils. Barricade coils are associated with more metallic artifact on TOF-MRA than Silent MRA. Silent MRA is useful for follow-up MRA after embolization using Barricade coils.

Utility of Low-Profile Visualized Intraluminal Support Junior Stent as a Rescue Therapy for Treating Ruptured Intracranial Aneurysms During Complicated Coil Embolization

BACKGROUND

Coil protrusion occasionally occurs during embolization and can lead to thromboembolic complications. We aimed to evaluate the efficacy of rescue stenting procedures with a low-profile stent system (LVIS Jr.) for treating ruptured intracranial aneurysms during complicated coil embolization.

METHODS

We performed a retrospective review to identify patients who had subarachnoid hemorrhage and were treated with LVIS Jr. stent rescue therapy. We enrolled 15 patients with intracranial aneurysms and evaluated the technical success and immediate postprocedural clinical and angiographic outcomes.

RESULTS

All 15 patients underwent successful rescue-stent treatment, and no thrombotic or hemorrhagic complications occurred. Immediate postprocedural angiography revealed complete aneurysm occlusion in 40% (6/15) of the patients, whereas 60% (9) of the patients had a residual neck. Among the 12 patients who underwent follow-up angiography, 10 (83.3%) patients had complete aneurysm occlusion, 1 (8.3%) had a residual neck, and 1 (8.3%) showed an increase in the filling status of the aneurysm. There were no thrombotic complications during the follow-up period.

CONCLUSIONS

Our findings indicate that LVIS Jr. stent rescue therapy is clinically useful for handling coil protrusion during the embolization of ruptured intracranial aneurysms.

Long Term Outcome of In-Stent Stenosis after Stent Assisted Coil Embolization for Cerebral Aneurysm

Objective

The objective of this study was to evaluatelong-term radiologic prognosis and characteristics of in-stent stenosis (ISS) after stent assisted coiling (SAC) for cerebral aneurysm and analyze its risk factors.

Methods

Radiological records of 362 cases of SAC during 10 years were retrospectively reviewed. Patients were included in this study if they had follow-up angiogram using catheter selected angiography at least twice. All subjected were followed up from 12 months to over 30 months. Of 120 patients, 123 aneurysms were enrolled. Patient data including age, sex, aneurysm size, neck size, procedural complication, kinds of stent, ISS associated symptom, ruptured state, location of ISS, degree of ISS, radiologic prognosis of ISS, follow-up period of time, and medical comorbidities such as hypertension, diabetes mellitus (DM), dyslipidemia, and smoking were collected.Statistical comparisons of group clinical characteristics were conducted for the total population.

Results

Among 123 casesof aneurysm, 22 cases (17.9%) of ISS were revealed on follow-up angiography. Multiple stenting was performed in three cases and intra-procedural rupture occurred in two cases. Most cases were asymptomatic and symptomatic stenosis was identified in only one case. Sixteen cases were ruptured aneurysm. Mild stenosis was observed in 11 cases. Moderate stenosis was found in eight cases and severe stenosis was identified in three cases. Mean timing of identification of ISS was 8.90 months. The most common type was proximal type. Most cases were improved or not changed on follow-up angiography. Only one case was aggravated from mild stenosis to occlusion of parent artery. Mean follow-up period was 44.3 months. We compared risk factors and characteristic between ISS group and non-ISS group using univariate analysis. Multiple stenting was performed for three cases (13.6%) of the ISS group and four cases (4.0%) of the non-ISS group, showing no statistical difference between the two groups (p=0.108). Additionally, the proportion of patients who had more than two risk factors among four medical risk factors (hypertension, DM, dyslipidemia, and smoking) was higher in the ISS group than that in the non-ISS group, the difference between the two was not statistically significant either (31.8% vs. 12.9%, p=0.05).

Conclusion

Clinical course and long-term prognosis of ISS might be benign. Most cases of ISS could be improved or not aggravated. Control of medical co-morbidity might be important. To the best of our knowledge, our study had more cases with longer follow-up period of time than other reports.

Long-Term Results and Follow-Up Examinations after Endovascular Embolization for Unruptured Cerebral Aneurysms

BACKGROUND AND PURPOSE

The appropriate period of follow-up examinations after endovascular embolization for cerebral aneurysms using time-of-flight MR angiography is not well-known. We retrospectively investigated long-term results after endovascular embolization for unruptured cerebral aneurysms and evaluated the periods from embolization to recanalization and retreatment.

MATERIALS AND METHODS

Between April 2006 and March 2011, one hundred forty-eight unruptured aneurysms were treated with endovascular coil embolization. Among them, we investigated 116 unruptured aneurysms, which were followed up for >5 years. Time-of-flight MR angiography was performed at 1 day, 3-6 months, 1 year after the procedure, and every year thereafter.

RESULTS

The mean follow-up period was 7.0 ± 1.4 years. Recanalization was observed in 19 (16.3%) aneurysms within 2 years. Among them, retreatment for recanalization was performed in 8 (6.8%) aneurysms. No recanalization was detected in any aneurysms that had been stable in the first 2 years after embolization. A larger maximum aneurysm size was significantly correlated with recanalization (P = .019).

CONCLUSIONS

Aneurysms in which recanalization was not observed within 2 years after endovascular coil embolization were stable during a mean follow-up of 7 years. This result may be helpful in considering the appropriate span or frequency of follow-up imaging for embolized cerebral aneurysms.

MRA versus DSA for the follow-up imaging of intracranial aneurysms treated using endovascular techniques: a meta-analysis

BACKGROUND

Treated aneurysms must be followed over time to ensure durable occlusion, as more than 20% of endovascularly treated aneurysms recur. While digital subtraction angiography (DSA) remains the gold standard, magnetic resonance angiography (MRA) is attractive as a non-invasive follow-up technique. Two different MRA techniques have traditionally been used: time-of-flight (TOF) and contrast-enhanced (CE) MRA. We analysed data from studies comparing MRA techniques with DSA for the follow-up of aneurysms undergoing endovascular treatment. Subgroup analysis of stent-assisted coiling (SAC) and flow diversion (FD) techniques was completed.

METHODS

Comprehensive searches using the Embase, PubMed, and Cochrane databases were performed and updated to November 2018. Pooled sensitivity and specificity were calculated using aneurysm occlusion status as defined by the Raymond-Roy occlusion grading scale.

RESULTS

The literature search yielded 1579 unique titles. Forty-three studies were included. For TOF-MRA, sensitivity and specificity of all aneurysms undergoing endovascular therapy were 88% and 94%, respectively. For CE-MRA, the sensitivity and specificity were 88% and 96%, respectively. For SAC and FD techniques, sensitivity and specificity of TOF-MRA were 86% and 95%, respectively. CE-MRA had sensitivity and specificity of 90% and 92%.

CONCLUSION

MRA is a reliable modality for the follow-up of aneurysms treated using endovascular techniques. While the data are limited, MRA techniques can also be used to reliably follow patients undergoing FD and SAC. However, clinical factors must be used to optimize follow-up regimens for individual patients.

Effectiveness of MRA on embolized intracranial aneurysms: a comparison of DSA, CE-MRA, and TOF-MRA

Purpose: The endovascular treatment of intracranial aneurysms was proven safe and effective compared to the alternative method of surgical clipping, despite the high recurrence rate. Follow-up of embolized intracranial aneurysms is mandatory for the early detection of recurrence and improved outcomes. DSA is used as the reference standard for this assessment. To determine the effectiveness of MRA in follow-up evaluations of intracranial aneurysms after embolization by comparing DSA, CE-MRA, and TOF-MRA.

Materials and Methods: Sixty-eight consecutive patients undergoing DSA, TOF-MRA, and CE-MRA during an interval of <1 week were enrolled in this 6-month study. Images were evaluated for occlusion status, patency of the parent vessels, and artifacts. The modified Raymond-Roy occlusion classification and Aneurysm Embolization Grades were used to assess the occlusion status and initial DSA images for detection of recurrence in two filtered study phases with optimized selection criteria. Seventeen observers (phase I: 9, phase II: 8) independently interpreted the double-blinded images. Agreement was expressed with a Fleiss kappa value; p < 0.05 was considered significant.

Results: This study included 68 patients with 77 aneurysms; 38 (49.35%) were treated with coil alone and 39 (50.65%) with stent-assisted coiling. In both phases, DSA was superior to TOF-MRA and CE-MRA using MRRC (Phase I: k = 0.567, p ≤ 0.001; k = 0.287, p ≤ 0.001; k = 0.117, p ≤ 0.001, respectively; Phase II: k = 0.503, p ≤ 0.001; k = 0.303, p ≤ 0.001; k = 0.115, p = 0.038, respectively). TOF-MRA was as effective as DSA (TOF: k = 0.335, p ≤ 0.001; DSA: k = 0.323, p ≤ 0.001) for recurrence detection.

Conclusion: We suggest TOF-MRA as a first-line follow-up tool to detect aneurysm recurrence, and DSA to quantify the filling space to make a definite decision on re-embolization.

Hemodynamic Differences Between Recurrent and Nonrecurrent Intracranial Aneurysms: Fluid Dynamics Simulations Based on MR Angiography

BACKGROUND AND PURPOSE

Although the role of wall shear stress (WSS) in the initiation, growth, and rupture of intracranial aneurysms has been well studied, its influence on aneurysm recurrence after endovascular treatment requires further investigation. We aimed to compare WSS at necks of recurrent and nonrecurrent aneurysms.

METHODS

Nine recurrent coil-embolized aneurysms were identified and matched with nine nonrecurrent aneurysms. Patient-specific vessel geometries reconstructed from follow-up 3-D time-of-flight magnetic resonance angiography were analyzed using computational fluid dynamics (CFD) simulations. Absolute WSS and the percentage of abnormally low and high WSS at the aneurysm neck compared to the near artery were measured.

RESULTS

The median percentage of abnormal WSS at the aneurysm neck was 49.3% for recurrent and 34.7% for nonrecurrent aneurysms (P = .011). The area under the receiver-operating-characteristic curve for distinguishing these aneurysms according to the percentage of abnormal WSS was .86 (95% CI .62 to .98). The optimal cut-off value of 45.1% resulted in a sensitivity and a specificity of 88.89% (95% CI 51.8% to 99.7%).

CONCLUSION

Our findings indicate that necks of recurrent aneurysms are exposed to abnormal WSS to a larger extent. Abnormal WSS may serve as a metric to distinguish them from nonrecurrent aneurysms with CFD simulations a priori.

Time-resolved magnetic resonance angiography (TR-MRA) for the evaluation of post coiling aneurysms; A quantitative analysis of the residual aneurysm using full-width at half-maximum (FWHM) value

Magnetic resonance image (MRI) is now widely used for imaging follow-up for post coiling brain aneurysms. However, the accuracy on the estimation of residual aneurysm, which is crucial for the retreatment planning, remains to be controversial. The purpose of this study is to evaluate a new post-processing technique that provides improved estimation of the residual aneurysm after coil embolization. One hundred aneurysms on 93 patients who underwent coil embolization for brain aneurysm were evaluated using the 1.5 Tesla time-resolved magnetic resonance angiography (TR-MRA) one year after the treatment. To minimize the inter-observer variability caused by the window level adjustment, an automatic post processing protocol using the full-width at half-maximum (FWHM) value was utilized. The result was then compared with that from the conventional cerebral angiography. Of the 97 aneurysms that underwent both TR-MRA and DSA, 23 (23.7%) showed residual neck / dome during follow-up. After window level adjustment, the size of the parent artery in the TR-MRA was consistent with that in the DSA. The reconstructed Volume Rendering images provided clear contours of the residual aneurysms and contributed to the understanding the configuration of residual aneurysm. The largest and the smallest diameter of the residual aneurysms was larger in the TR-MRA than in the DSA (8.05 vs. 7.72 mm, p = 0.0004; 4.99 vs. 4.19 mm, p = 0.007 respectively). The sensitivity, specificity, and positive and negative predictive values of TR-MRA compared to DSA were 100%, 97%, 73%, and 100%, respectively. Using the FWHM value to optimize the window level adjustment, the size of the residual component observed in the TR-MRA was larger compared to that in the DSA whereas the size of neck and the parent artery showed consistency between the two modalities. This image processing technique can be used as an effective screening tool for evaluating residual component in post-coiling brain aneurysms.

Mid-term 3T MRA follow-up of intracranial aneurysms treated with the Woven EndoBridge

INTRODUCTION

Angiography is the standard follow-up modality for treated aneurysms with the Woven EndoBridge (WEB), and magnetic resonance angiography (MRA) is useful for extended follow-up. We present the results of WEB-treated aneurysms with angiographic follow-up at three months and at least 18 months' 3T MRA follow-up.

MATERIALS AND METHODS

Included were 52 patients with 53 aneurysms treated with the WEB between February 2015 and July 2016. There were 29 women and 23 men with a mean age of 60 years (median 62, range 23-76). Mean aneurysm size was 6.2 mm (median 6, range 3-16 mm).

RESULTS

3T MRA follow-up was mean 19.6 months (median 18, range 18-36 months). One patient had an aneurysm remnant at three-month angiography that was additionally coiled and with stable complete occlusion at 18 months' 3T MRA follow-up. At three-month follow-up angiography, 44 aneurysms were completely occluded and eight had a neck remnant. At latest 3T MRA, stable complete occlusion was present in 43 aneurysms and stable neck remnant in eight. One posterior cerebral artery (PCA) dissection aneurysm was stable at three and six months but was enlarged and reopened at 18 months, confirmed with angiography. Focal signal loss by the proximal marker of the WEB was apparent in four patients without compromising diagnostic evaluation.

CONCLUSION

WEB-treated aneurysms with adequate occlusion at three-month angiography remained stable during serial 3T MRA follow-up of 18-36 months. One PCA aneurysm reopened during the 6- to 18-month interval. Once the WEB-treated aneurysm is adequately occluded in the short term, later reopening is uncommon.

Comparison of postsurgical clinical sequences between completely embolized and incompletely embolized patients with wide nicked intracranial aneurysms treated with stent assisted coil embolization technique: A STROBE-compliant study

The technique of stent-assisted coil embolization has been widely used in the clinic, while its efficacy and safety have yet to be evaluated. This study investigates the values of computed tomography angiography (CTA), magnetic resonance angiography (MRA), and digital subtraction angiography (DSA) in evaluating the Enterprise stent-assisted coil embolization in the treatment of intracranial wide-necked aneurysm.A total of 578 intracranial wide-necked aneurysm patients confirmed by MRA + CTA + DSA examinations were included and treated with Enterprise stent-assisted coil embolization in this study. All patients were assigned into complete embolization (CE) group and incomplete embolization (IE) group according to the results of postoperative MRA + CTA + DSA examinations and Raymond grades. Hunt-Hess grades, incidence of complication and Glasgow Outcome Scale (GOS) grades of patients were investigated to assess the therapeutic effect of Enterprise stent-assisted coil embolization in intracranial wide-necked treatment. Multivariate logistic regression analysis was performed to assess risk factors for the therapeutic effect of Enterprise stent-assisted coil embolization in intracranial wide-necked aneurysm.CTA images offered a better and clearer view than MRA and DSA images in both the CE and IE groups. Both the sensitivity and specificity of CTA were apparently higher than those of MRA. Patients in the CE group enjoyed a higher good GOS rate but a lower incidence of complication than those in the IE group. In Enterprise stent-assisted coil embolization treatment, the Hunt-Hess grade, hypertension, and size of artery aneurysm were independent factors affecting the therapeutic effect of Enterprise stent-assisted coil embolization in intracranial wide-necked aneurysm.Compared with MRA, CTA shows a higher value in evaluating the therapeutic effect of Enterprise stent-assisted coil embolization for the treatment of intracranial wide-necked aneurysm, and can thus serve as an important means of predicting the therapeutic effect of endovascular intervention in treating patients with intracranial wide-necked aneurysm.

Wide-neck bifurcation aneurysms of the middle cerebral artery and basilar apex treated by endovascular techniques: a multicentre, core lab adjudicated study evaluating safety and durability of occlusion (BRANCH)

Background and purpose

BRANCH (wide-neck bifurcation aneurysms of the middle cerebral artery and basilar apex treated by endovascular techniques) is a multicentre, retrospective study comparing core lab evaluation of angiographic outcomes with self-reported outcomes.

Materials and methods

Consecutive patients were enrolled from 10 US centres, aged between 18 and 85 with unruptured wide-neck middle cerebral artery (MCA) or basilar apex aneurysms treated endovascularly. Patient demographics, aneurysm morphology, procedural information, mortality and morbidity data and core lab and self-reported modified Raymond Roy (RR) outcomes were obtained.

Results

115 patients met inclusion criteria. Intervention-related mortality and significant morbidity rates were 1.7% (2/115) and 5.8% (6/103) respectively. Core lab adjudicated RR1 and 2 occlusion rates at follow-up were 30.6% and 32.4% respectively. The retreatment rate within the follow-up window was 10/115 (8.7%) and in stent stenosis at follow-up was 5/63 (7.9%). Self-reporting shows a statistically significant direction to angiographic RR one outcomes at follow-up compared with core lab evaluation, with OR 1.75 (95% CI 1.08 to 2.83).

Conclusion

Endovascular treatment of wide-neck MCA and basilar apex aneurysms resulted in a core lab adjudicated RR1 occlusion rate of 30.6%. Self-reported results at follow-up favour better angiographic outcomes, with OR 1.75 (95% CI 1.08 to 2.83). These data demonstrate the need for novel endovascular devices specifically designed to treat complex intracranial aneurysms, as well as the importance of core lab adjudication in assessing outcomes in such a trial.

Meta-analysis of computed tomography angiography versus magnetic resonance angiography for intracranial aneurysm

BACKGROUND

Whether the diagnosis value of computed tomography angiography (CTA) for intracranial aneurysm is in accordance with magnetic resonance angiography (MRA) remains inconclusive. This meta-analysis aims to synthesize relevant studies to compare the diagnostic efficacies of the 2 methods.

METHODS

Potentially relevant studies were selected through PubMed, Embase, Wanfang, Chongqing VIP, and China National Knowledge Infrastructure databases by using the core terms "computer tomography angiography" (CTA) and "magnetic resonance angiography" (MRA) and "intracranial aneurysm*" in the titles, abstracts, and keywords of the articles. Quality Assessment for Diagnostic Accuracy Studies (QUADAS-2) was utilized to evaluate the quality. Pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were count. Summary receiver operating characteristic curves (SROC) and area under the curve (AUC) were used to summarize the overall diagnostic performance. Statistical analyses were performed by Stata version 12.0 and MetaDisc 1.4 software.

RESULTS

Ten articles were identified in this current paper. For CTA, the pooled estimates of diagnostic parameters for intracranial aneurysm were as follows: sensitivity, 0.84 (95%CI = 0.81-0.86); specificity, 0.85 (95%CI = 0.79-0.89); PLR, 4.09 (95%CI = 2.45-6.81); NLR, 0.18 (95%CI = 0.11-0.28); DOR, 23.74 (95%CI = 10.49-53.74); AUC, 0.90, respectively. For MRA, the pooled estimates of diagnostic parameters for intracranial aneurysm were as follows: sensitivity, 0.80 (95%CI = 0.77-0.83); specificity, 0.87 (95%CI = 0.82-0.91); PLR, 3.61 (95%CI = 1.72-7.55); NLR; 0.27 (95%CI = 0.21-0.35); DOR, 16.77 (95%CI = 7.38-38.11); AUC, 0.87, respectively. No significant difference was found the AUC value between CTA and MRA for intracranial aneurysm (Z = 0.828, P > .05).

CONCLUSION

This comprehensive meta-analysis demonstrated that the diagnosis value of CTA was in accordance with MRA for intracranial aneurysm. However, considering the limitation of sample size, the results should be treated with caution.

ACR Appropriateness Criteria® Cerebrovascular Disease

Diseases of the cerebral vasculature represent a heterogeneous group of ischemic and hemorrhagic etiologies, which often manifest clinically as an acute neurologic deficit also known as stroke or less commonly with symptoms such as headache or seizures. Stroke is the fourth leading cause of death and is a leading cause of serious long-term disability in the United States. Eighty-seven percent of strokes are ischemic, 10% are due to intracerebral hemorrhage, and 3% are secondary to subarachnoid hemorrhage. The past two decades have seen significant developments in the screening, diagnosis, and treatment of ischemic and hemorrhagic causes of stroke with advancements in CT and MRI technology and novel treatment devices and techniques. Multiple different imaging modalities can be used in the evaluation of cerebrovascular disease. The different imaging modalities all have their own niches and their own advantages and disadvantages in the evaluation of cerebrovascular disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

An experimental rabbit model of symptomatic cerebral vasospasm with in vivo neuroimaging assessment and ex vivo histological validation

Cerebral vasospasm (CVS) is a severe complication that occurs following aneurysmal subarachnoid hemorrhage (SAH). Magnetic resonance angiography (MRA) has been used to evaluate brain injury following SAH in humans. The present study was designed to assess a rabbit model of symptomatic CVS (SCVS) and the utility of MRA in evaluating SCVS in rabbits. Japanese white rabbits (n=24) were randomly divided into 2 equal groups: A sham group and a SAH group. Neurological scores were evaluated for 7 days following SAH. Basilar artery (BA) diameters were measured using MRA preoperatively and 7 days postoperatively. Rabbits were sacrificed 7 days following SAH and the BA diameter of each rabbit was determined using histological evaluation. Compared with the Sham group, neurological function was significantly reduced in the SAH group at all time points (P<0.05). Furthermore, the BA diameter was significantly smaller in the SAH group on day 7 compared with the baseline measurement (P<0.05). No significant difference was observed between histological and MRA findings in either group at day 7. Histological changes in the hippocampus consistent with ischemia were observed in the SAH group. Hippocampal ischemia was also identified in the SAH group via MRA and there was no difference in detection rates following the use of MRA and histochemistry. MRA appears to be an effective method for assessing vasospasms of the BA and ischemic changes to the hippocampus in a rabbit model of SCVS. Furthermore, the animal model used in the present study may be beneficial for the future study of SCVS.