Opinion: imaging follow-up after coiling of intracranial aneurysms

Long-Term Hemorrhage and Reperfusion Rates of Coiled Aneurysms: A Single-Center Experience

Background: The endovascular approach has emerged as standard therapy for many intracranial aneurysms (IAs) to prevent hemorrhage, yet its long-term durability varies considerably. The aim of this study was to evaluate the safety and effectiveness of an initially deliberate endovascular approach regarding IA hemorrhage rates over a long-term follow-up period. Methods: This retrospective single-center study included all consecutive patients with endovascularly treated IAs who presented between January 2008 and December 2020 with a follow-up of at least 12 months. The primary endpoint was the proportion of patients with long-term IA hemorrhage rates and reperfusion. The secondary endpoint was treatment-related morbidity and mortality. Independent risk factors for IA reperfusion over the long term were analyzed using multivariate logistic regression. Results: Endovascular treatment was the therapy of choice for 333 patients with IAs, among whom 188 (57%) experienced rupture upon presentation. Complete coiling (Raymond I) was noted in 162 (49%) of the patients, with primary supportive devices being used in 51 (15%) patients. After a median (±SD) follow-up time of 34 ± 41 months (range 12-265 months), IA reperfusion was noted in 158 (47%), necessitating retreatment in 105 (32%) of the patients. Over the long term, hemorrhage was noted in four (1%) patients. Multivariate analysis revealed aneurysmal multilobarity (HR 1.8, 95%CI 1.2-2.7; p = 0.004) and a patient age of ≥50 years (HR 1.7, 95% CI 1.1-2.5, p = 0.01) as independent predictors of reperfusion over time. Intervention-related morbidity was noted in 16 (4.8%) patients, namely, thrombosis formation and contrast extravasation in 8 (2.4%) patients each, while no intervention-induced mortality was observed. Conclusion: In the long term, the hemorrhage rate in patients with IA with an initially more conservative endovascular approach is low. Therefore, a deliberate endovascular treatment approach might be justified.

Feasibility of intraoperative MRI for endovascular coiling of intracranial aneurysms: A single centre experience

BACKGROUND

Intraoperative magnetic resonance imaging system (iMRIS) surgical theatre is a highly integrated operating room with an intraoperative magnetic resonance imaging (iMRI) designed originally for brain tumour surgery. Its use in neurointerventional procedures, particularly in the setting of endovascular coiling of intracranial aneurysms, has not been discussed in the literature to date. We present our initial experience about the safety and feasibility of iMRI to assess post operative complications and provide baseline imaging post coiling of intracranial aneurysms.

METHODS

Consecutive patients who underwent iMRI between 2015 and 2018 were included in the study. Demographic, clinical details, endovascular technique and surgical outcomes were collected. Details of anesthesia during the procedure were also collected.

RESULTS

Fifteen patients underwent iMRI with MRA to assess post coiling status of their elective endovascular coiling of intracranial aneurysms. The mean age in this cohort was 61 years and 46.7% were male. No immediate complications were seen either from the endovascular procedures or from the iMRI. All iMRI scans were performed as planned with no aborted or truncated scans. The image quality of the iMRI/MRA was adequate to detect the residual aneurysm, if present. There was no residual aneurysm on the angiogram that were not detected on the iMRIs. Of the 15 patients, 10 were safely discharged the following day and other 5 were discharged 2 days after their surgery.

CONCLUSIONS

The iMRI is an advantageous tool which can be integrated into neurointerventional workflow resulting in early post peri-procedural feedback and potentially reduced post-operative hospital stay.

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.

Angiographic Follow-Up for Small Ruptured Intracranial Aneurysm Treated by Endovascular Treatment : Follow-Up Plan and Long-Term Follow-Up Results

Objective

Although endovascular treatment for intracranial aneurysms is considered effective and safe, its durability is still debated. Also, few studies have described angiographic follow-up plan after endovascular treatment of intracranial aneurysm, especially in ruptured cases. Hence, we report the long-term results of follow-up angiography protocol.

Methods

Radiological records of 639 cases of coil embolization with ruptured aneurysms from March 2003 to December 2016 were retrospectively reviewed. Patients who received treatment of a saccular aneurysm less than 7 mm resulted with near complete occlusion were included. Two hundred thirty-eight aneuryms which received the follow-up angiography at least once were enrolled. We classified four periods of follow-up as follows : post-treatment 1 year (defined as the first period), from 1 to 2 years (the second period), 2 to 5 years (the third period), and over 5 years (long-term).

Results

We identified 14 cases (6.4%) of recurrence from 218 aneurysms in follow-up angiography in the first period. Among 143 aneurysms in the second period, five cases (3.5%) of recurrence were identified. There were no findings suspicious of recanalization in 97 patients in the third period. Of the total 238 cases, there were 19 recurrences, for a recurrence rate of 8.0%. Six (31.6%) out of 19 recurrences showed a tendency toward repeat recurrences even after additional treatment. Twenty-eight received long-term follow-up over 5 years and there was no recurrence.

Conclusion

Most of the recurrence were found during the first and the second year. We suggest that at least one digital subtraction angiography examination may be necessary around post-treatment 2 years, especially in ruptured cases. If the angiographic results are favorable at 2 years post-treatment, long-term result should be favorable.

Numerical Assessment of the Risk of Abnormal Endothelialization for Diverter Devices: Clinical Data Driven Numerical Study

Numerical modeling is an effective tool for preoperative planning. The present work is devoted to a retrospective analysis of neurosurgical treatments for the occlusion of cerebral aneurysms using flow-diverters and hemodynamic factors affecting stent endothelization. Several different geometric approaches have been considered for virtual flow-diverters deployment. A comparative analysis of hemodynamic parameters as a result of computational modeling has been carried out basing on the four clinical cases: one successful treatment, one with no occlusion and two with in stent stenosis. For the first time, a quantitative assessment of both: the limiting magnitude of shear stresses that are necessary for the occurrence of in stent stenosis (MaxWSS > 1.23) and for conditions in which endothelialization is insufficiently active and occlusion of the cervical part of the aneurysm does not occur (MaxWSS < 1.68)—has been statistacally proven (p < 0.01).

Longitudinal Cost Profiles of Pipeline Embolization Device Versus Stent-Assisted Coiling in Propensity-Matched Unruptured Small Anterior Circulation Aneurysms

BACKGROUND

The cost profiles of stent-assisted coiling (SAC) vs Pipeline embolization device (PED) in small unruptured anterior circulation aneurysms have not been studied.

OBJECTIVE

To compare the 2 modalities cost profiles in a propensity-matched cohort controlling for potential technical complexity confounders including size and location.

METHODS

Patients treated with either SAC or PED at our institution were identified. Following propensity-score algorithm, 46 patients, 23 in each group were matched. The procedural and follow-up costs in each group were analyzed and compared.

RESULTS

Median maximal aneurysm size in the SAC and PED cohort were 5.3 vs 5.1 mm, respectively. Costs of access guide materials were significantly higher in the SAC group (P < .01). The average implant cost was not significantly different between the SAC and PED cohorts (${\$}$13973.2 ± ${\$}$2886.2 vs ${\$}$14,760.7 ± ${\$}$3782.1, respectively; P = .43). Similarly, total procedural costs were not different (${\$}$18341.5 ± 4104 vs ${\$}$17484.3 ± 2914.1, respectively, P = .42). Although there were significantly more total follow-ups (P = .02) and longer follow-up duration (P = .01) in SAC cohort, no significant difference in follow-up costs between the 2 groups was identified (${\$}$20557 ± ${\$}$9247 vs ${\$}$18958 ± ${\$}$9171.9, P = .56). Overall cost was similar between the SAC (${\$}$38898.9 ± ${\$}$9645.5) and PED groups (${\$}$36442.4 ± ${\$}$9076) (P = .38).

CONCLUSION

In small unruptured anterior circulation aneurysms (excluding anterior communicating artery aneurysms) matched for technical complexity confounders, SAC and PED offer an overall equivalent economic cost profile. Postprocedural noninvasive imaging was more frequent in the SAC group. However, follow-up costs and total costs were not significantly different.

Early major recurrence of cerebral aneurysms after satisfactory initial coiling

BACKGROUND AND PURPOSE

Early major recurrence (EMR) of cerebral aneurysms treated by coiling has not been investigated. The purpose of this study is to characterize the frequency and risk factors of this phenomenon.

MATERIALS AND METHODS

A retrospective review was performed of consecutive patients who presented with ruptured and unruptured cerebral aneurysms and underwent coiling from July 2009 to June 2019 at a university hospital. We defined EMR as recurrence of the aneurysm greater than its initial size within the first 6 months of an initial satisfactory coil embolization. Patient demographics, clinical information, aneurysm characteristics, angiographic and technical details were reviewed.

RESULTS

From July 2009 to June 2019, 338 aneurysms (190 unruptured aneurysms and 148 ruptured cerebral aneurysms) underwent coiling and satisfied our study criteria. Among these patients, 23 patients (19 ruptured and 4 unruptured aneurysms) were found to have recurrent aneurysm. Of those, 4 were found to have early major aneurysm regrowth occurring within 6 months after coiling (1.2%). The detection of the EMR was as early as 4 weeks and as late as 20 weeks after the initial coil embolization. The average detection time was 10 ± 7.2 weeks (mean ± SD, range:4-20 weeks). In each case, the recurrent aneurysm cavity was more than twice the initial size of presentation. All aneurysms with major recurrence were ruptured with low aspect ratios (dome height to neck ratio) and involved a communicating segment. All patients underwent successful retreatment of the recurrent aneurysm with good outcome.

CONCLUSIONS

Early major recurrence of treated aneurysms is a rare but important complication that harbors an impending risk of re-rupture. Early control angiography after endovascular coiling may be warranted for small ruptured aneurysms, even in cases in which the initial result seems technically satisfactory.

Clinical outcome of endovascular coil embolization for cerebral aneurysms in Asian population in relation to risk factors: a 3-year retrospective analysis

Background

Long term results of endovascular coiling are yet scarce. This study reviews the impact of comorbidities on the success of endovascular coiling of both ruptured and unruptured intracranial aneurysms. Endovascular treatment has become thetreatment of choice after the ISAT trials. Independent risk factors that influence recovery are age, sex, smoking, and hypertension.

Methods

This is a 3-year retrospective analysis, performed to assess the clinical and radiological outcome of patients with cerebral aneurysms treated with detachable coils in an Asian population with relation to comorbidities including smoking and hypertension with age and gender as mediators. From July 2015 to August 2018, a total of 297 consecutive patients (mean age: 45.5 years) with cerebral aneurysms both ruptured and unruptured who were treated at a single center with endovascular coiling procedures are included in the study. Clinical information and radiological outcomes were evaluated on regular follow-ups and telephonic interviews. A modified Rankin Scale was used to measure the clinical outcomes in patients.

Results

We have found that smoking harmed clinical outcome, with smokers 35% less likely to recover, while hypertension played a smaller role with only 15%. It was found that while aneurysms are more prevalent in women than men, women not only have a higher chance of getting an aneurysm but also have poorer outcomes. Similarly, patients who were above the age of 40 had a lower chance of recovery compared to younger patients due to comorbidities irrespective of gender.

Conclusion

Asian sub-continent has different genetic markers that lead to poorer outcomes of aneurysms in women, while outcomes are similar in men and women in developed nations. Smoking does not play a major role in women’s recovery. Men with comorbidity seemed to be at higher risk and age played a major role in their recovery.

Residuals, recurrences and re-treatment after endovascular repair of intracranial aneurysms: A retrospective methodological comparison

OBJECTIVE

Incomplete aneurysm occlusions and re-treatment rates of 52 and 10-30%, respectively, have been reported following endovascular treatment of intracranial aneurysms, raising clinical concerns regarding procedural efficacy. We compare residual, recurrence and re-treatment rates subject to different endovascular techniques in both ruptured and unruptured intracranial aneurysms at a comprehensive state-wide tertiary neurovascular centre in Australia.

METHODS

Medical records, procedural and follow-up imaging studies of all patients who underwent endovascular treatment for intracranial aneurysms between July 2010 and July 2017 were reviewed retrospectively. Residuals, recurrences and re-treatment rates were assessed regarding initial aneurysm rupture status and applied endovascular technique: primary coiling, balloon- and stent-assisted coiling and flow diversion.

RESULTS

Among 233 aneurysms, residual, recurrence and re-treatment rates were 27, 11.2 and 9.4%, respectively. Compared with unruptured aneurysms, similar residual and recurrence (p > .05), but higher re-treatment rates (4.5% vs. 19%; p < .001) were found for ruptured aneurysms. Residual, recurrence and re-treatment rates were: 13.3, 16 and 12% for primary coiling; 12, 12 and 10.7% for balloon-assisted coiling; 14.9, 7.5 and 4.5% for stent-assisted coiling; 91.9, 0 and 5.4% for flow diversion. Stent-assistance and flow-diversion were associated with lower recurrence and re-treatment rates, when compared with primary- and balloon-assisted coiling (p < .05).

CONCLUSIONS

Residuals and recurrences after endovascular treatment of intracranial aneurysms are less common than previously reported. Stent assistance and flow diversion seem associated with reduced recurrence- and re-treatment rates, when compared with primary- and balloon-assisted coiling. Restrained use of stents in ruptured aneurysms may be a contributing factor for higher recurrence/retreatment rates compared to unruptured aneurysms.

Voxel based analysis of recurrence dynamics in intracranial aneurysms after coiling

BACKGROUND

Understanding aneurysm growth is critical for the appropriate follow-up of patients after coil embolization and the need for retreatment. The purpose of the study was to stratify the growth dynamics of aneurysm recurrences after coiling by volumetric analysis and to determine predictive factors for aneurysm recurrences.

METHODS

Source images of follow-up three-dimensional time of flight MR angiography (ToF-MRA) scans were compared with the first post-interventional ToF-MRA scan and analyzed for residual flow after co-registration using ANALYZE-software. In the event of incomplete occlusion, the residual volume was segmented and calculated. Growth dynamic was determined for each aneurysm after embolization.

RESULTS

We analyzed 326 patients with 345 aneurysms from two centers. Each case had at least two ToF-MRA examinations after endovascular therapy. The mean observation interval was 59 months. Volumetric analysis of 1139 follow-up MRAs revealed that 218/345 aneurysms (63.2%) showed complete occlusion on initial follow-up imaging, and of these 95.0% remained stable. A steady increase in intra-aneurysmal flow was observed in 83/345 (24.1%). Less frequent observations were a steep increase (21/345; 6.1%) and a decrease (27/345; 7.8%). Independent predictors of increasing residual flow were greatest aneurysm diameter, total coil length, and incomplete occlusion.

CONCLUSIONS

Volumetric analysis of registered three-dimensional ToF-MRA follow-up datasets allows the detection of different growth patterns with high precision, avoids the low inter-rater reliability, and represents a promising approach for future studies that include analysis of more complex predictors of residual flow. In cases of aneurysm recurrence after coiling, the major pattern seems to be a steady increase in intra-aneurysmal flow over several months.

Cerebrovascular Imaging: Which Test is Best?

Optimal diagnosis and characterization of cerebrovascular disease requires selection of the appropriate imaging exam for each clinical situation. In this review, we focus on intracranial arterial disease and discuss the techniques in current clinical use for imaging the blood vessel lumen and blood vessel wall, and for mapping cerebral hemodynamic impairment at the tissue level. We then discuss specific strategies for imaging intracranial aneurysms, arteriovenous malformations, dural arterial venous fistulas, and arterial steno-occlusive disease.

Unruptured intracranial aneurysms: An updated review of current concepts for risk factors, detection and management

The management of patients with unruptured intracranial aneurysms (UIAs) is a complex clinical challenge and constitutes an immense field of research. While a preponderant proportion of these aneurysms never rupture, the consequences of such an event are severe and represent an important healthcare problem. To date, however, the natural history of UIAs is not completely understood and there is no accurate means to discriminate the UIAs that will rupture from those that will not. Yet, a good understanding of the recent evidence and future perspectives is needed when advising a patient with IA to tailor any information to the given patient's level of risk and psychoaffective status. Thus, this review addresses the current concepts of epidemiology, risk factors, detection and management of UIAs.

Treatment of ruptured intracranial aneurysms yesterday and now

Objective

This prospective study is designed to detect changes in the treatment of ruptured intracranial aneurysms over a period of 17 years.

Methods

We compared 361 treated cases of aneurysm occlusion after subarachnoid hemorrhage from 1997 to 2003 with 281 cases from 2006 to 2014. Specialists of neuroradiology and vascular neurosurgery decided over the modality assignment. We established a prospective data acquisition in both groups to detect significant differences within a follow-up time of one year. With this setting we evaluated the treatment methods over time and compared endovascular with microsurgical treatment.

Results

When compared to the earlier group, microsurgical treatment was less frequently chosen in the more recent collective because of neck-configuration. Endovascular treatment was chosen more frequently over time (31.9% versus 48.8%). Occurrence of initial symptomatic ischemic stroke was significantly lower in the clipping group compared to the endovascular group and remained stable over time. The number of reinterventions due to refilled treated aneurysms significantly decreased in the endovascular group at one-year follow-up, but the significantly better occlusion- and reintervention-rate of the microsurgical group persisted. The rebleeding rate in the endovascular group at one year follow-up decreased from 6.1% to 2.2% and showed no statistically significant difference to the microsurgical group, anymore (endovascular 2.2% versus microsurgical 0.0%, p = 0.11).

Conclusion

Microsurgical clipping still has some advantages, however endovascular treatment is improving rapidly.

Inter- and Intrarater Agreement on the Outcome of Endovascular Treatment of Aneurysms Using MRA

BACKGROUND AND PURPOSE

Patients treated with coiling are often followed by MR angiography. Our objective was to assess the inter- and intraobserver agreement in diagnosing aneurysm remnants and recurrences by using multimodality imaging, including TOF MRA.

MATERIALS AND METHODS

A portfolio composed of 120 selected images from 56 patients was sent to 15 neuroradiologists from 10 institutions. For each case, raters were asked to classify angiographic results (3 classes) of 2 studies (32 MRA-MRA and 24 DSA-MRA pairs) and to provide a final judgment regarding the presence of a recurrence (no, minor, major). Six raters were asked to independently review the portfolio twice. A second study, restricted to 4 raters having full access to all images, was designed to validate the results of the electronic survey.

RESULTS

The proportion of cases judged to have a major recurrence varied between 16.1% and 71.4% (mean, 35.0% ± 12.7%). There was moderate agreement overall (κ = 0.474 ± 0.009), increasing to nearly substantial (κ = 0.581 ± 0.014) when the judgment was dichotomized (presence or absence of a major recurrence). Agreement on cases followed-up by MRA-MRA was similarly substantial (κ = 0.601 ± 0.018). The intrarater agreement varied between fair (κ = 0.257 ± 0.093) and substantial (κ= 0.699 ± 0.084), improving with a dichotomized judgment concerning MRA-MRA comparisons. Agreement was no better when raters had access to all images.

CONCLUSIONS

There is an important variability in the assessment of angiographic outcomes of endovascular treatments. Agreement on the presence of a major recurrence when comparing 2 MRA studies or the MRA with the last catheter angiographic study can be substantial.

Coil Embolization of Intracranial Aneurysms: A Six-Month Follow-Up Study

Background:

Rupture of the intracranial aneurysms is associated with a high risk of bleeding and a high incidence of mortality if left untreated.

Objectives:

The aim of this study is to report our experience in managing intracranial aneurysms using coil embolization and to report the 6-month follow-up outcome of the patients.

Patients and Methods:

From January 2010 to December 2012, a series of 90 nonrandomized consecutive patients (mean age: 44.6 ± 14.9 years) with intracranial aneurysms underwent endovascular coil embolization in our center. We excluded patients with dissecting, blood blister-like, or false aneurysms. All patients were evaluated by four-vessel angiography to determine the shape, size, number and location of the aneurysms. We recommended a six-month follow-up control angiography. However, only 38 of them participated in this follow-up imaging. The data were analyzed by chi-square, fisher exact and t-tests and alpha was considered lower than 5%.

Results:

Immediately after the procedure, the total occlusion was seen in 76 (86.4%), subtotal occlusion in six (6.8%), and partial occlusion in six patients (6.8%). There was no significant relationship between the aneurysm size, aneurysm neck size, and location of the aneurysm with total or subtotal occlusions. Eleven patients (12.5%) experienced some complication during the procedure including two tears, three focal neurological signs, three vision disturbances, and three bleedings in the aneurysm. Major complications were significantly higher in the posterior aneurysm compared to the anterior ones (55.6% versus 44.4% of the major complications; P value = 0.015). Among patients who underwent control angiography, 34 patients (89.4%) had no change, two (5.3%) had new growth and two (5.3%) had widening of the neck after 6 months follow-up. Although aneurysms that remained unchanged after six months follow-up angiography had total occlusion after the procedure, it was 50% for aneurysms that had any changes in 6 months follow-up angiography (P value = 0.01).

Conclusion:

Coil embolization showed successful outcomes in the treatment of intracranial aneurysms with a low complication rate.

Clinical and Imaging Follow-Up of Patients with Coiled Basilar Tip Aneurysms Up to 20 Years

BACKGROUND AND PURPOSE

Long-term follow-up data of coiled basilar tip aneurysms are scarce, and little is known about the risk of late aneurysm-related adverse events. We followed a cohort of 154 patients with basilar tip aneurysms coiled between 1995 and 2006.

MATERIALS AND METHODS

Imaging and clinical data were retrospectively reviewed. The incidence and timing of retreatment, rebleeds, and progressive mass effect by continuous aneurysm growth were recorded. Risk factors for retreatment were assessed.

RESULTS

Clinical follow-up of 144 of 154 patients who survived the admission period was a mean of 9.8 years (median, 10.2; range, 0.3-20.1 years). During this period, 37 basilar tip aneurysms (26%) were additionally coiled (annual incidence rate, 2.6%; 95% CI, 1.8%-3.6%). Aneurysm size of >15 mm was the most important independent predictor for retreatment (OR, 8.7; 95% CI, 3.4-22.5). The first additional coiling was performed in the first year of follow-up in 17 of 37 patients (46%) and in 20 patients (54%) at a later time up to 17.2 years. Nine rebleeds occurred in 9 of 106 patients who initially presented with SAH after a median follow-up of 8.3 years (range, 0.3-16.6 years). The annual incidence rate was 0.7% (95% CI, 0.4%-1.5%). Eight patients died of aneurysm-related adverse events: 3 of rebleed and 5 of progressive mass effect.

CONCLUSIONS

Retreatment of coiled basilar tip aneurysms was frequently needed during follow-up, also at long intervals. Most late mortality was from progressive mass effect, not from rebleeds. Life-long MRA follow-up at yearly intervals is recommended.

Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is a worldwide health burden with high fatality and permanent disability rates. The overall prognosis depends on the volume of the initial bleed, rebleeding, and degree of delayed cerebral ischemia (DCI). Cardiac manifestations and neurogenic pulmonary edema indicate the severity of SAH. The International Subarachnoid Aneurysm Trial (ISAT) reported a favorable neurological outcome with the endovascular coiling procedure compared with surgical clipping at the end of 1 year. The ISAT trial recruits were primarily neurologically good grade patients with smaller anterior circulation aneurysms, and therefore the results cannot be reliably extrapolated to larger aneurysms, posterior circulation aneurysms, patients presenting with complex aneurysm morphology, and poor neurological grades. The role of hypothermia is not proven to be neuroprotective according to a large randomized controlled trial, Intraoperative Hypothermia for Aneurysms Surgery Trial (IHAST II), which recruited patients with good neurological grades. Patients in this trial were subjected to slow cooling and inadequate cooling time and were rewarmed rapidly. This methodology would have reduced the beneficial effects of hypothermia. Adenosine is found to be beneficial for transient induced hypotension in 2 retrospective analyses, without increasing the risk for cardiac and neurological morbidity. The neurological benefit of pharmacological neuroprotection and neuromonitoring is not proven in patients undergoing clipping of aneurysms. DCI is an important cause of morbidity and mortality following SAH, and the pathophysiology is likely multifactorial and not yet understood. At present, oral nimodipine has an established role in the management of DCI, along with maintenance of euvolemia and induced hypertension. Following SAH, hypernatremia, although less common than hyponatremia, is a predictor of poor neurological outcome.

Volume measurement of the intracranial aneurysm: a discussion and comparison of the alternatives to manual segmentation

OBJECTIVE

Several modalities are available for volumetric measurement of the intracranial aneurysm. We discuss the challenges involved in manual segmentation, and analyze the application of alternative methods using automatic segmentation and geometric formulae in measurement of aneurysm volumes and coil packing density.

METHODS

The volumes and morphology of 38 aneurysms treated with endovascular coiling at a single center were measured using three-dimensional rotational angiography (3DRA) reconstruction software using automatic segmentation. Aneurysm volumes were also calculated from their height, width, depth, size of neck, and assumed shape in 3DRA images using simple geometric formulae. The aneurysm volumes were dichotomized as "small" or "large" using the median volume of the studied population (54 mm(3)) measured by automatic segmentation as the cut-off value for further statistical analysis.

RESULTS

A greater proportion of aneurysms were categorized as being "small" when geometric formulae were applied. The median aneurysm volumes obtained were 54.5 mm(3) by 3DRA software, and 30.6 mm(3) using mathematical equations. An underestimation of aneurysm volume with a resultant overestimation in the calculated coil packing density (p = 0.002) was observed.

CONCLUSION

Caution must be exercised in the application of simple geometric formulae in the management of intracranial aneurysms as volumes may potentially be underestimated and packing densities falsely elevated. Future research should focus on validation of automatic segmentation in volumetric measurement and improving its accuracy to enhance its application in clinical practice.

[Neuroimaging follow-up of cerebral aneurysms treated with endovascular techniques]

There are no specific recommendations in clinical guidelines about the best time, imaging tests, or intervals for following up patients with intracranial aneurysms treated with endovascular techniques. We reviewed the literature, using the following keywords to search in the main medical databases: cerebral aneurysm, coils, endovascular procedure, and follow-up. Within the Cerebrovascular Disease Group of the Spanish Society of Neuroradiology, we aimed to propose recommendations and an orientative protocol based on the scientific evidence for using neuroimaging to monitor intracranial aneurysms that have been treated with endovascular techniques. We aimed to specify the most appropriate neuroimaging techniques, the interval, the time of follow-up, and the best approach to defining the imaging findings, with the ultimate goal of improving clinical outcomes while optimizing and rationalizing the use of available resources.

Time-resolved Magnetic Resonance Angiography for assessment of recanalization after coil embolization of visceral artery aneurysms

Background:

Follow-up imaging after coil embolization of visceral artery aneurysms is important for detecting recanalization. However, CT examination is susceptible to coil artifacts, which sometimes makes it difficult to assess recanalization. We report 2 cases where recanalization was successfully visualized using time-resolved magnetic resonance angiography after coil embolization of visceral artery aneurysms (one case of right internal iliac artery aneurysm and one case of splenic artery aneurysm). Repeat coil embolization was successfully performed.

Case Report:

Case 1. An 80-year-old male patient with right internal iliac artery (IIA) aneurysm underwent coil embolization. Aneurysm was located at the bifurcation of the right IIA and therefore, after making a femorofemoral bypass, the distal part of the right IIA, aneurysm and the common iliac artery were embolized with a coil. One year later, the size of the aneurysm seemed to have increased on CT. However, the details were not determined because of metal artifacts. Thus, time-resolved MRA was performed and showed minute vascular flow inside the aneurysm. Angiography was subsequently performed and blood flow inside the aneurysm was visualized similar to the findings in time-resolved MRA. Coil embolization was performed once more and vascular flow inside the aneurysm disappeared. Case 2. A 36-year-old male patient with a splenic artery aneurysm underwent coil packing with preservation of splenic artery patency. Four years later, coil compaction was suspected in a CT scan, but CT could not evaluate recanalization because of severe metal artifacts. Angiography was subsequently performed, showing recanalization of the aneurysm as did the time-resolved MRA. Therefore, coil embolization of the aneurysm and splenic artery was performed again.

Conclusions:

Follow-up imaging after coil embolization of visceral artery aneurysms is important for detecting recanalization. However, it is sometimes difficult to assess recanalization with CT because of artifacts caused by metal. In our cases, recanalization of aneurysms was clearly shown by time-resolved MRA and re-embolization was successfully performed.

In conclusion, time-resolved MRA appears to be useful in assessment of recanalization of visceral artery aneurysms after coil embolization.

Follow-up after embolization of ruptured intracranial aneurysms: a prospective comparison of two-dimensional digital subtraction angiography, three-dimensional digital subtraction angiography, and time-of-flight magnetic resonance angiography

INTRODUCTION

To prospectively compare of the diagnostic value of digital subtraction angiography (DSA) and time-of-flight magnetic resonance angiography (TOF-MRA) in the follow-up of intracranial aneurysms after endovascular treatment.

METHODS

Seventy-two consecutive patients were examined 3 months after the embolization. The index tests included: two-dimensional DSA (2D-DSA), three-dimensional DSA (3D-DSA), and TOF-MRA. The reference test was a retrospective consensus between 2D-DSA images, 3D-DSA images, and source rotational DSA images. The evaluation included: detection of the residual flow, quantification of the flow, and validity of the decision regarding retreatment. Intraobserver agreement and interobserver agreement were determined.

RESULTS

The sensitivity and specificity of residual flow detection ranged from 84.6 % (2D-DSA and TOF-MRA) to 92.3 % (3D-DSA) and from 91.3 % (TOF-MRA) to 97.8 % (3D-DSA), respectively. The accuracy of occlusion degree evaluation ranged from 0.78 (2D-DSA) to 0.92 (3D-DSA, Cohen's kappa). The 2D-DSA method presented lower performance in the decision on retreatment than 3D-DSA (P < 0.05, ROC analysis). The intraobserver agreement was very good for all techniques (κ = 0.80-0.97). The interobserver agreement was moderate for TOF-MRA and very good for 2D-DSA and 3D-DSA (κ = 0.72-0.94).

CONCLUSION

Considering the invasiveness of DSA and the minor difference in the diagnostic performance between 3D-DSA and TOF-MRA, the latter method should be the first-line modality for follow-up after aneurysm embolization.

Time-resolved imaging of contrast kinetics does not improve performance of follow-up MRA of embolized intracranial aneurysms

Background

The use of contrast media and the time-resolved imaging of contrast kinetics (TRICKS) technique have some theoretical advantages over time-of-flight magnetic resonance angiography (TOF-MRA) in the follow-up of intracranial aneurysms after endovascular treatment. We prospectively compared the diagnostic performance of TRICKS and TOF-MRA with digital subtracted angiography (DSA) in the assessment of occlusion of embolized aneurysms.

Material/Methods

Seventy-two consecutive patients with 72 aneurysms were examined 3 months after embolization. Test characteristics of TOF-MRA and TRICKS were calculated for the detection of residual flow. The results of quantification of flow were compared with weighted kappa. Intraobserver and interobserver reproducibility was determined.

Results

The sensitivity of TOF-MRA was 85% (95% CI, 65–96%) and of TRICKS, 89% (95% CI, 70–97%). The specificity of both methods was 91% (95% CI, 79–98%). The accuracy of the flow quantification ranged from 0.76 (TOF-MRA) to 0.83 (TRICKS). There was no significant difference between the methods in the area under the ROC curve regarding both the detection and the quantification of flow. Intraobserver reproducibility was very good with both techniques (kappa, 0.86–0.89). The interobserver reproducibility was moderate for TOF-MRA and very good for TRICKS (kappa, 0.74–0.80).

Conclusions

In this study, TOF-MRA and TRICKS presented similar diagnostic performance; therefore, the use of time-resolved contrast-enhanced MRA is not justified in the follow-up of embolized aneurysms.

DSA volumetric 3D reconstructions of intracranial aneurysms: A pictorial essay

A gold standard of cerebral vessel imaging remains the digital subtraction angiography (DSA) performed in three projections. However, in specific clinical cases, many additional projections are required, or a complete visualization of a lesion may even be impossible with 2D angiography. Three-dimensional (3D) reconstructions of rotational angiography were reported to improve the performance of DSA significantly. In this pictorial essay, specific applications of this technique are presented in the management of intracranial aneurysms, including: preoperative aneurysm evaluation, intraoperative imaging, and follow-up. Volumetric reconstructions of 3D DSA are a valuable tool for cerebral vessels imaging. They play a vital role in the assessment of intracranial aneurysms, especially in evaluation of the aneurysm neck and the aneurysm recanalization.

Comparison of remnant size in embolized intracranial aneurysms measured at follow-up with DSA and MRA

INTRODUCTION

The possibility of recanalization and the need for retreatment are the most important limitations of intracranial aneurysm embolization. The purpose of the study was to compare the size of aneurysm remnants measured at follow-up with three-dimensional digital subtracted angiography (3D-DSA) and magnetic resonance angiography (MRA).

METHODS

Twenty-six aneurysms were found incompletely occluded in 72 consecutively examined patients at a follow-up after 3 months. The diameters and volume of aneurysm remnants were compared between 3D-DSA, time-of-flight MRA (TOF-MRA), contrast-enhanced TOF-MRA (CE-TOF-MRA), and contrast-enhanced MRA (CE-MRA) at 1.5 T.

RESULTS

There was a significant correlation between remnant volumes calculated based on 3D-DSA and all MRA modalities. The intraobserver variability of the measurements ranged from 3.4 to 4.1 % and the interobserver variability from 5.8 to 7.3 %. There were no significant differences in the variability between the techniques. The mean residual filling volume ranged from 16.3 ± 19.0 mm(3) in TOF-MRA to 30.5 ± 44.6 mm(3) in 3D-DSA (P < 0.04). Significant differences were found in the volumes measured with 3D-DSA and CE-MRA as compared to TOF-MRA and CE-TOF-MRA (P < 0.01). There was a moderate significant correlation between the residual filling and the relative error of measurement in the case of TOF-MRA and CE-TOF-MRA.

CONCLUSIONS

TOF-MRA seems to underestimate the size of aneurysm remnants detected at follow-up and should not be used as a sole imaging method to decide on re-embolization.

Temporal evolution of susceptibility artifacts from coiled aneurysms on MR angiography: an in vivo canine study

BACKGROUND AND PURPOSE

Intracranial aneurysms treated by coiling have a risk for recurrence, requiring surveillance imaging. MRA has emerged as an attractive technique for postcoiling aneurysm imaging. Previous research has evaluated MR imaging artifacts of the coil mass in vitro. Our aim in this study was to evaluate MR imaging artifacts of coiled aneurysms in vivo with time.

MATERIALS AND METHODS

Four sidewall aneurysms were created in each of 4 dogs. Aneurysms were embolized receiving only 1 type of coils. After embolization, the animals were transferred to MR imaging, which included axial 3D TOF MRA (TEs, 3.5, 5, and 6.9 ms), phase-contrast MRA, and coronal CE-MRA. MR imaging studies were repeated at 1, 4, 6, 8, 14, and 28 weeks. We calculated an OEF: OEF = V(A)/V(CM), where the numerator represents the volume of the MR imaging artifacts and the denominator is the true volume of the coil mass measured by 3D RA.

RESULTS

OEFs were largest immediately after embolization and showed a gradual decay until approximately 4 weeks, when there was stabilization of the size of the artifacts. By 4 weeks, there was mild coil compaction (average coil mass volume decrease of 7.8%); however, the OEFs decreased by 25% after 4 weeks (P < .001).

CONCLUSIONS

MR imaging susceptibility artifacts change with time, being maximal in the postembolization setting and decaying until 4 weeks. The clinical implications of this study are that baseline MRA for comparison with future imaging should be acquired at a minimum of 1 week after the procedure.

Factors predicting retreatment and residual aneurysms at 1 year after endovascular coiling for ruptured cerebral aneurysms: Prospective Registry of Subarachnoid Aneurysms Treatment (PRESAT) in Japan

INTRODUCTION

Endovascular treatment of cerebral aneurysms includes follow-up imaging to identify aneurysms that may need retreatment. The aim of this study was to determine predictors of incomplete aneurysm occlusion at 1 year after endovascular coiling for ruptured cerebral aneurysms.

METHODS

In 129 patients of the Prospective Registry of Subarachnoid Aneurysms Treatment cohort, ruptured aneurysms were coiled within 14 days of onset and both initial post-coiling and 1-year follow-up digital subtraction angiography or magnetic resonance angiography were obtained. Factors predicting 1-year incomplete aneurysm occlusion (retreatment within 1-year or residual aneurysms at 1 year) were determined using multivariate logistic regression analyses.

RESULTS

One-year incomplete aneurysm occlusion was identified in 59 patients, including ten patients who were retreated within 1-year post-coiling. Dome size ≥7.5 mm (P = 0.007, odds ratio (OR) = 5.00, 95% confidence interval (CI) = 1.55-16.15), pre-treatment aneurysm re-rupture (P = 0.023, OR = 3.50, 95% CI = 1.19-10.31), non-small size/small neck aneurysm (dome size, ≥10 mm or neck size, ≥4 mm; P = 0.022, OR = 3.26, 95% CI = 1.19-8.96), and residual aneurysms on immediate post-coiling angiograms (P = 0.017, OR = 1.43, 95% CI = 1.07-1.93) significantly predicted incomplete aneurysm occlusion at 1-year post-coiling.

CONCLUSIONS

In addition to the characteristics of aneurysm and initially incomplete aneurysm occlusion, this study showed pre-treatment aneurysm re-rupture to be a predictor that favors closer imaging follow-ups for coiled aneurysms.

Long-term MRA follow-up after coiling of intracranial aneurysms: impact on mood and anxiety

Introduction

Magnetic resonance angiography (MRA) screening for recurrence of a coiled intracranial aneurysm and formation of new aneurysms long-term after coiling may induce anxiety and depression. In coiled patients, we evaluated effects on mood and level of anxiety from long-term follow-up MRA in comparison to general population norms.

Methods

Of 162 patients participating in a long-term (>4.5 years) MRA follow-up after coiling, 120 completed the EQ-5D questionnaire, a visual analog health scale and a self-developed screening related questionnaire at the time of MRA. Three months later, the same questionnaires were completed by 100 of these 120 patients. Results were compared to general population norms adjusted for gender and age.

Results

Any problem with anxiety or depression was reported in 56 of 120 patients (47%; 95%CI38↔56%) at baseline and 42 of 100 patients (42%; 95%CI32↔52%) at 3 months, equally for screen-positives and -negatives. Compared to the reference population, participants scored 38% (95%CI9↔67%) and 27% (95%CI4↔50%) more often any problem with anxiety or depression. Three months after screening, 21% (20 of 92) of screen-negatives and 13% (one of eight) of screen-positives reported to be less afraid of subarachnoid hemorrhage (SAH) compared to before screening. One of eight screen-positives reported increased fear of SAH.

Conclusions

Patients with coiled intracranial aneurysms participating in long-term MRA screening reported significantly more often to be anxious or depressed than a reference group. Screening did not significantly increase anxiety or depression temporarily. However, subjectively, patients did report an increase in anxiety caused by screening, which decreased after 3 months.

Unruptured intracranial aneurysms: initial and follow-up screening

Subarachnoid hemorrhage (SAH) from a ruptured intracranial aneurysm is a devastating disease that causes death or severe disability in half of patients. Intracranial aneurysms are not present at birth but develop during life. Actively searching and treating intracranial aneurysms before rupture may prevent SAH as a result of these aneurysms. The prevalence of intracranial aneurysms is approximately 2% in the general population, but higher in subgroups such as patients who have survived an episode of SAH, persons with a family history of SAH and patients with polycystic kidney disease. Screening for intracranial aneurysms should be considered in these high-risk groups. Some of the intracranial aneurysms detected with screening will be too small to be treated, and may therefore be followed over time, which can cause anxiety in the patient. In this article, we discuss current knowledge, remaining questions and future perspectives in screening and follow-up imaging for unruptured intracranial aneurysms.