Is Stent Retraction to ReLieve Arterial Cerebral VaSospasm Caused by SAH (Stent-ReLACSS) Using PRELAX the Long-awaited Solution for Treatment of Posthemorrhagic Cerebral Vasospasm? : Treatment of Posthemorrhagic Cerebral Vasospasm with PRESET and PRELAX: Technical Aspects, Efficacy, and Safety Margins in a Case Series

PURPOSE

Recent observational studies have indicated the efficacy of stent retriever devices for the treatment of posthemorrhagic cerebral vasospasm (CVS), both by deployment and on-site withdrawal into the microcatheter (stent angioplasty, SA) and deployment followed by retraction through the target vessel similar to thrombectomy (Stent Retraction to reLieve Arterial Cerebral vaSospasm caused by SAH, Stent-ReLACSS). This article reports the findings with each application of pRESET and pRELAX in the treatment of CVS.

METHODS

We retrospectively enrolled 25 patients with severe CVS following aneurysmal subarachnoid hemorrhage. For the SA group, a stent retriever or a pRELAX was temporarily deployed into a narrow vessel segment and retrieved into the microcatheter after 3 min. For the Stent-ReLACSS group, a pRELAX was temporarily deployed into a narrow vessel and pulled back unfolded into the internal carotid artery. If intra-arterial vasodilators were administered, they were given exclusively after mechanical vasospasmolysis to maximize the effectiveness of the stent treatment.

RESULTS

In this study fifteen patients and 49 vessels were treated with SA. All were technically successful without periprocedural complications; however, 8/15 patients (53.3%) required additional treatment of the CVS. A total of 10 patients and 23 vessel segments were treated with Stent-ReLACSS. All maneuvers were technically successful without periprocedural complications and all vessels showed significant angiographic improvement. No recurrent CVS requiring further endovascular treatment occurred in-hospital, and neither territorial ischemia in the treated vessels nor vascular injury were observed in follow-up angiography.

CONCLUSION

Based on the presented data it appears that Stent-ReLACSS with pRELAX does not pose any additional risks when used to treat CVS and might be superior to SA, especially concerning mid-term and long-term efficacy. The mechanism of action may be an effect on the endothelium rather than mechanical vasodilation. As many patients with CVS are diagnosed too late, prophylactic treatment of high-risk patients (e.g., poor grade, young, female) is potentially viable.

Anomalous origin of the middle meningeal artery from the inferolateral trunk with an arterial circle around a hypoplastic internal carotid artery in an infant with a dural arteriovenous fistula

Deviations from normal embryologic development can manifest in different anatomical variants of the ophthalmic artery. We present a case of an infant treated for a high-flow dural arteriovenous fistula of the superior sagittal sinus, in whom an arterial circle involving the ophthalmic artery, the middle meningeal artery, the inferolateral trunk and a hypoplastic segment of the internal carotid artery was found. The embryologic development is briefly reviewed with emphasis on the possible genesis of this interesting constellation.

Mechanical thrombectomy for recurrent large vessel occlusion

Although mechanical thrombectomy (MT) has been shown in numerous trials to be a successful treatment option for patients with large vessel occlusion (LVO), there is limited information on the safety and effectiveness of the technique in cases of recurrent LVO. To this end, we performed a retrospective review of our prospectively maintained database to identify all patients that had undergone more than one MT procedure January 2008 and January 2018. The data collected on these patients included baseline demographics and any history of diabetes mellitus, hypercholesterolaemia, hypertension, atrial fibrillation or smoking. We also recorded when the symptoms had started, the patient's NIHSS and ASPECT scores, the number of passes taken, the patient's final TICI score, any complications which arose and the patient's mRS at 90 days. Our dataset encompassed 25 patients (of which 17 (68%) were female) who had undergone a total number of 52 MT's. Average age at 1st presentation was 70 ± 12.8 years. The median time between one stroke and the next was 71 days (range 1-1059, IQR 183 days). The majority of the strokes were deemed cardioembolic (86.5%) in origin. There was no significant difference in the procedure times, number of passes or TICI scores. There was a significant difference in the mRS after the 1st and 2nd events (p = 0.014) but no significant difference if the 2nd event occurred contralateral to the 1st event (p = 0.66) (n = 22). It is therefore concluded that recurrent thrombectomy can be safely performed with no significant difference in the technical aspects of the procedure.

Basilar artery perforator aneurysms: Report of 9 cases and review of the literature

Basilar perforator artery aneurysms (BAPA's) are an under-recognised cause of sub-arachnoid haemorrhage (SAH). We present our single centre experience of BAPA's and review of the literature. We performed a retrospective review of our prospectively maintained database to identify all BAPA's that presented acute SAH between February 2009 and February 2018. We identified 9 patients (male = 7), each with a single aneurysm, and average age 55 ± 9.7 years. All aneurysms were small, 2.1 ± 0.5 mm (range 1-3 mm). Three aneurysms were not detected on initial angiography. Six aneurysms were treated with flow diversion, 3 were managed conservatively. No repeat haemorrhage occurred in the flow diverted patients. One patient treated conservatively suffered a repeat haemorrhage and died (mRS 6). Follow up imaging (n = 7), at average 5.6 months (range 3-12 months), showed complete occlusion in all the flow-diverted aneurysms and no change in one conservatively managed patient. There was no evidence of perforator infarction on the follow-up post treatment imaging. Clinical follow-up data was available in 8 patients, 6 of whom (75%) had a good outcome (mRS ≤ 2). A high index of suspicion is required to diagnose BAPA. Flow diversion can be used to treat BAPA's with acceptable risk of perforator infarction and low risk of repeat haemorrhage.

Microsurgical clipping and endovascular flow diversion of ruptured anterior circulation blood blister-like aneurysms

BACKGROUND

Detection and treatment of blister-like intracranial aneurysms as a source of subarachnoid hemorrhage (SAH) can be challenging. In the past the results of both microsurgical and endovascular treatment were difficult. We present our experience with the treatment of blister-like aneurysms in the acute phase of SAH using microsurgical clipping, endovascular parent vessel occlusion or flow diversion.

METHODS

A retrospective analysis of the cases of eight consecutive patients presenting in the acute phase after SAH from an intracranial blister aneurysm was performed. The demographic data of the patients, aneurysm characteristics, the clinical results of the treatment and the follow-up examinations were recorded. Procedural safety margins and aneurysm occlusion on follow-up digital subtraction angiography were the main interest of this evaluation.

RESULTS

Between January 2012 and November 2017 a total of eight ruptured blister aneurysms were treated in our center, six patients endovascularly. Five patients were treated in the acute phase of SAH, four by flow diversion. All endovascular procedures were feasible and no procedure-related complications were observed, especially no recurrent hemorrhage. In the first angiographic follow-up all blood blister-like aneurysms were completely occluded; two of the six patients treated by flow diverter implantation showed mild, transient intimal hyperplasia without clinical symptoms or the need for treatment.

CONCLUSIONS

Endovascular flow diversion is a viable option in the acute phase after SAH due to the rupture of a blister aneurysm. Implants with reduced thrombogenicity, obviating dual-platelet function inhibition, and flow diverters for vessel bifurcations would extend the indications for this treatment modality.

High-Grade Dural Arteriovenous Fistulas : Use of Kaneka ED Coils with the Marathon Microcatheter for Transvenous Coil Embolization

BACKGROUND

Dural arteriovenous fistulas (DAVF) are commonly encountered lesions that can be treated both transvenously, transarterially or using a combined approach.

OBJECTIVE

Transvenous coil embolization of DAVF is a recognized treatment option but can be challenging. In this context this article presents clinical experience using the Kaneka ED10 ExtraSoft coils in combination with the Marathon microcatheter to treat high grade DAVF. The physical properties of these coils and the microcatheter were also determined.

MATERIAL AND METHODS

All patients with high grade DAVF treated with the Marathon and the Kaneka ED COIL ∞10 ExtraSoft coils were retrospectively identified. The clinical presentation, location, grade of the lesion, clinical and radiological follow-up data were recorded. Bench side studies were performed to determine the physical properties of the Marathon catheter in comparison to the SL10 and Headway Duo as well the maximum width of the Kaneka pusher wire in comparison to Hypersoft, Target and Axium Prime coils.

RESULTS

A total of 8 patients with 9 DAVF with 3 Cognard 3 and 6 Cognard 4 lesions were identified. All the DAVF's were occluded either at the end of the procedure or on follow-up imaging. On bench side tests the Marathon microcatheter had the most flexible distal tip and distal shaft in comparison to the SL10 and Headway Duo. The proximal shaft of the Marathon was stiffer than the SL10. The Kaneka ED COIL ∞10 ExtraSoft had the smallest distal width and were the only coils tested that could be deployed through a Marathon microcatheter.

CONCLUSION

The combination of the Marathon microcatheter and Kaneka ED COIL ∞10 ExtraSoft is useful for the treatment of high grade DAVF.

Treatment of Unruptured, Saccular, Anterior Choroidal Artery Aneurysms with Flow Diversion : A Single Centre Experience

Background

The region of the brain supplied by the anterior choroidal artery (AChoA) is exquisitely eloquent. Aneurysms arising at or close to the origin of the vessel are not uncommon and damage or occlusion to the vessel can result in devastating consequences. The optimal treatment strategy is yet to be determined.

Objective

We sought to determine the efficacy of flow diversion for the treatment of unruptured AChoA aneurysms.

Method

A retrospective review of our prospectively maintained database was performed to identify all patients with unruptured aneurysms of the AChoA between March 2009 and May 2017. The fundus size, number and type of flow-diverting stent (FD), complications and follow-up data were recorded.

Results

We identified 30 patients (60% female), average age 52.8 ± 10.8 years (range 27–73), with 30 aneurysms. The aneurysms were generally small with a mean fundus diameter of 3.4 mm (range 1–7 mm). Early angiographic follow-up data were available for all patients at which point 15 aneurysms were completely occluded (50%). Delayed angiographic follow-up was available in 24 patients and occlusion was seen in 21 patients (87.5%). Of the patients one developed transient ischemic symptoms after interruption of the antiplatelet medication and another patient had a small embolic infarct with transient symptoms in the periprocedural period.

Conclusion

Flow diversion can be used to successfully treat aneurysms of the AChoA. The treatment carries a high rate of technical and radiological success with a good safety profile.

Difference in aneurysm characteristics between ruptured and unruptured aneurysms in patients with multiple intracranial aneurysms

Background:

The risk of aneurysmal rupture is dependent upon numerous factors, however, there are inconsistencies in the results between studies, which may be due to confounding factors. This can be avoided by comparing the characteristics of ruptured and unruptured aneurysms within the same patient. We sought to analyze the aneurysm characteristics of patients with acute aneurysmal subarachnoid hemorrhage (SAH) and multiple intracranial aneurysms.

Methods:

We reviewed our prospectively maintained institutional database, between 01/10/2007 and 01/01/2017, for all patients with confirmed SAH and >1 aneurysm. We recorded the size, location, and morphology and calculated secondary geometric indices such as bottleneck factor and aspect ratio.

Results:

During the study period, a total of 694 patients with aneurysmal SAH were admitted to our institution. We identified 113 patients (74.3% female, average age 51.7 ± 12.3). The majority of patients had only one associate unruptured aneurysm (79.6%). The average unruptured aneurysm was 3.1 ± 1.5 mm and the average ruptured aneurysm was 5.7 ± 2.7 mm (P < 0.001). In the multivariate analysis, aneurysm location, aneurysm morphology, and size were independently associated with rupture. A complex aneurysm morphology was the strongest risk factor for rupture (OR, 29.27; 95% CI 14.33–59.78; P < 0.001) with size >7 mm (OR, 17.74; 95% CI 4.07–77.35; P < 0.001), and AcomA location also showing a strong independent association.

Conclusion:

Size plays an important part in determining rupture risk, however, other factors such as location and in particular morphology must also be considered. We believe that the introduction of vessel wall imaging will help to risk stratify aneurysms.

The Size of Ruptured Intracranial Aneurysms : A 10-Year Series from a Single Center

PURPOSE

There is a controversy concerning the risk of rupture of small intracranial aneurysms. We sought to determine the size and morphological features of ruptured intracranial aneurysms.

MATERIAL AND METHODS

The hospital files and images from all patients referred during one decade (2007-2016) to a specialized neurovascular center were retrospectively reviewed. Neck diameter, fundus depth and width as well as neck width based on catheter angiography were measured. Aneurysm morphology was classified as either regular, lobulated, irregular or fusiform.

RESULTS

A total of 694 consecutive patients with aneurysmal subarachnoid hemorrhage (aSAH) were identified (65.9% female, median age 54.3 years). The anterior communicating artery (AcomA) was the most frequent location of ruptured aneurysms. The medians for aneurysm depth, width and neck diameter were 5 mm, 4.5 mm and 3 mm, respectively. A regular contour of the aneurysm sac was found in 19%.

CONCLUSION

The majority of aSAH are caused by small intracranial aneurysms. There is no safety margin in terms of small aneurysm size of regular shape without daughter aneurysms. Treatment should also be offered to patients with small, regularly shaped intracranial aneurysms, together with an empirical risk-benefit assessment.

[Management of paraophthalmic aneurysms : Review of endovascular treatment strategies]

BACKGROUND

Aneurysms of the cerebral vessels are relatively common and aneurysms of the ophthalmic segment of the internal carotid artery (ICA) represent approximately 10% of intradural aneurysms.

ANATOMICAL ASPECTS

The ophthalmic segment of the ICA extends from the origin of the ophthalmic artery to the origin of the posterior communicating artery. Aneurysms can originate from the ophthalmic artery itself or directly from the ICA at a distance from the ophthalmic artery. The various anatomic configurations can alter the risks of treatment.

SURGICAL TREATMENT

Surgical treatment of aneurysms of the ophthalmic segment poses unique challenges for the neurosurgeon, given the deep location and complex nearby structures and optic nerve. The necessity to remove the clinoid process can make the operation technically challenging.

ENDOVASCULAR TREATMENT

Endovascular treatment of paraophthalmic aneurysms includes coil occlusion, and also stent- or balloon-assisted coil occlusion. More recently, hemodynamically active flow diverter stents improved the treatment results.

CONCLUSION

The management of paraophthalmic aneurysms is associated with specific risks. Careful consideration of the available techniques is necessary before each invention. Coil-occlusion remains the first choice for ruptured paraophthalmic aneurysms. For unruptured paraophthalmic aneurysms flow diversion offers improved results. The overall complication rates of these procedures are low; however, cerebral ischemia, intracranial hemorrhage and visual complications must be considered in advance and the patient must be informed of the risks.

Mechanical thrombectomy in patients with M1 occlusion and NIHSS score ≤5: a single-centre experience

Background

The recent success of several mechanical thrombectomy trials has resulted in a significant change in management for patients presenting with stroke. However, it is still unclear how to manage patients that present with stroke and low National Institutes of Health Stroke Scale (NIHSS) ≤5. We sought to review our experience of mechanical thrombectomy in patients with low NIHSS and confirmed M1 occlusion.

Methods

We retrospectively analysed our prospectively maintained database of all patients undergoing mechanical thrombectomy between January 2008 and August 2016. We identified 41 patients with confirmed M1 occlusion and low NIHSS (≤5) on admission to our hospital. We collected demographic, radiological, procedural and outcome data.

Results

The mean age of patients was 72±14, with 20 male patients. Associated medical conditions were common with hypertension seen in ∼80%. Just over 50% presented with NIHSS 4 or 5. The average ASPECTS score on admission was 8.8 (range 6–10), and the average clot length 10 mm. Angiographically Thrombolysis in Cerebral Infarction (TICI) ≥2b was obtained in 87.8% of patients. 7 patients had haemorrhage on follow-up, 2 of which were symptomatic. Of 40 patients with 90-day follow-up, 75% had modified Rankin Scale (mRS) score 0–2. There were 3 deaths at 90 days.

Conclusions

Mechanical thrombectomy in patients with low NIHSS and proximal large vessel occlusion is technically possible and carries a high degree of success with good safety profile. Patients with low NIHSS and confirmed occlusion should be considered for mechanical thrombectomy.

Treatment of posterior circulation non-saccular aneurysms with flow diverters: a single-center experience and review of 56 patients

BACKGROUND AND PURPOSE

Non-saccular aneurysms of the posterior fossa are an uncommon pathology with no clear treatment strategy. The use of flow-diverting stents (FDS) has had mixed results. We sought to evaluate our experience of FDS for the treatment of this pathology.

METHODS

We retrospectively reviewed our database of prospectively collected information for all patients treated only with flow diversion for an unruptured non-saccular aneurysm of the posterior circulation between February 2009 and April 2016. The aneurysms were classified as dolichoectasia, fusiform or transitional, and imaging characteristics including maximal diameter, disease vessel segment, MRI features (intra-aneurysmal thrombus, T1 hyperintensity in the aneurysmal wall, infarctions in the territory of the posterior circulation, and mass effect) were recorded alongside clinical and follow-up data.

RESULTS

We identified 56 patients (45 men) with 58 aneurysms. The average age of the patients was 63.5 years. Twenty-two patients were symptomatic from the aneurysms at presentation. The majority of the lesions were vertebrobasilar in location (44.8%) with isolated vertebral lesions representing 29.3% of aneurysms. Transitional aneurysms were the most common (48.2%). The mean maximal diameter of the aneurysms was 11 mm. Angiographic exclusion of the aneurysms was seen in 57.4% of aneurysms with follow-up (n=47). During the follow-up period nine patients died.

CONCLUSIONS

Treatment of non-saccular aneurysms of the posterior fossa is technically possible. Early treatment, particularly of the fusiform and transitional subtypes, is recognized, as is treatment prior to the development of symptoms. A 'watch and wait' strategy with regular imaging follow-up could be employed for asymptomatic dolichoectasia.

Use of flow diverters in the treatment of unruptured saccular aneurysms of the anterior cerebral artery

BACKGROUND

Few publications have dealt exclusively with the use of flow diverter stents for the treatment of aneurysms of the anterior cerebral artery (ACA).

OBJECTIVE

To determine the efficacy of flow-diverting stents in the treatment of small, unruptured aneurysms of the ACA.

METHODS

We retrospectively reviewed our database of prospectively collected information for all patients treated with flow diversion for an unruptured saccular aneurysm of the ACA between September 2009 and July 2016. The aneurysm fundus size, neck size, number and type of flow-diverting stent (FDS), complications, and follow-up data were recorded.

RESULTS

In total 26 patients, with 27 aneurysms were identified that matched our inclusion criteria (11 male and 15 female). The average age of the patients was 59.3 years (range 27-77 years). All patients, except one, had a single aneurysm affecting the ACA. Fourteen aneurysms were located on the left (51.9%). The average aneurysm fundus size was 2.9 mm (range 2-6 mm). Twenty patients had follow-up angiographic studies. In total, 16 aneurysms were completely excluded, 1 aneurysm showed a very small remnant, and no follow-up angiographic data are available for the remaining patients. One patient had a treatment-related complication.

CONCLUSIONS

Treatment of aneurysms arising from the ACA with flow diverters is technically feasible and carries a high degree of success with low complication rate.

Use of the pCONus as an adjunct to coil embolization of acutely ruptured aneurysms

Introduction

Coil embolization of ruptured aneurysms has become the standard treatment in many situations. However, certain aneurysm morphologies pose technical difficulties and may require the use of adjunctive devices.

Objective

To present our experience with the pCONus, a new neck bridging device, as an adjunct to coil embolization for acutely ruptured aneurysms and discuss the technical success, angiographic and clinical outcomes.

Methods

We conducted a retrospective review of our database of prospectively collected data to identify all patients who presented with acute subarachnoid hemorrhage that required adjunctive treatment with the pCONus in the acute stage. We searched the database between April 2011 and April 2016.

Results

21 patients were identified (13 male, 8 female) with an average age of 54.6 years (range 31–73). 8 aneurysms were located at the basilar artery tip, 7 at the anterior communicating artery, 4 at the middle cerebral artery bifurcation, 1 pericallosal, and 1 basilar fenestration. 61.8% patients achieved modified Raymond–Roy classification I or II at immediate angiography, with 75% of patients having completely occluded aneurysms or stable appearance at initial follow-up. There were no repeat aneurysmal ruptures and two device-related complications (no permanent morbidity). Four patients in our cohort died.

Conclusions

Use of the pCONus is safe and effective in patients with acutely ruptured aneurysms and carries a high rate of technical success.

Direct carotid cavernous sinus fistulae: vessel reconstruction using flow-diverting implants

Purpose

Retrospective evaluation of our experience with the use of flow diverters (FD) for the endovascular treatment of direct carotid-cavernous sinus fistulae (diCCF).

Methods

Between 2011 and 2015, 14 consecutive patients with 14 diCCF were treated with FD alone or in combination with other implants in a single institution.

Results

A total of 21 sessions were performed in 14 patients. FD placement was technically successful in all cases without an adverse event. Patients were treated with FD alone (n = 5), FD and covered stents (n = 2), FD and coils (n = 7). A total of 59 FD (24 Pipeline Embolization Device, Medtronic; 35 p64 Flow Modulation Device, phenox), 291 coils, and 3 stent grafts were used. Three of 14 diCCF were completely occluded after the 1^st session, a minor residual shunt was found in 7/14, and in the remaining 4/14 patients, the shunt volume was reduced significantly. The mean follow-up period encompassed 20 months. Additional treatment included transvenous coil occlusion (n = 3) and/or further FD deployment (n = 5). An asymptomatic internal carotid artery (ICA) occlusion was encountered in 2 patients, related to an interruption of antiaggregation. At the last follow-up, 10/14 patients were free from ocular symptoms (71 %), 2 had residual exophthalmos, and no patient had clinical deterioration.

Conclusion

The usage of FD for the treatment of diCCF is straightforward. Injury of the cranial nerves can be avoided. In most cases, ocular symptoms improve. Several FD layers and/or an adjunctive venous coil occlusion are required. Complete occlusion of a diCCF may take weeks or months and long-term antiaggregation is required. In the future, a flexible stent graft might be a better solution.

Initial Experience with p64: A Novel Mechanically Detachable Flow Diverter for the Treatment of Intracranial Saccular Sidewall Aneurysms

BACKGROUND AND PURPOSE

Flow diverters are important tools for the treatment of intracranial aneurysms. We report a retrospective evaluation of the safety and efficacy of p64, a fully resheathable, detachable flow diverter, in the endovascular treatment of intracranial sidewall aneurysms.

MATERIALS AND METHODS

Results of 121 patients with 130 aneurysms (median neck size, 3 mm; median fundus size, 4 mm), treated from April 2012 through October 2014, were analyzed. Aneurysms were unruptured or beyond the acute SAH phase. Thirteen aneurysms were located in the posterior circulation. Twenty-three aneurysms had previous saccular treatment but no previous parent vessel stent placement. In 19 aneurysms, a combination of coiling and flow diversion was performed.

RESULTS

Successful p64 deployment was achieved in 127/130 aneurysms. The average number of p64s used was 1.1 per aneurysm. The rates of transient and permanent morbidity and mortality were 5%, 1.7%, and 0.8%, respectively. Three-month DSA follow-up in 123/130 aneurysms showed complete occlusion in 58.5%. Nine-month DSA follow-up in 93/106 (87.7%) eligible aneurysms showed complete occlusion in 79.6%. Late follow-up (median, 496 days) has already been performed in 35 aneurysms, showing complete occlusion in 30 (85.7%).

CONCLUSIONS

p64 offers an efficacious treatment option for intracranial sidewall aneurysms with a high aneurysm occlusion and an acceptable complication rate. The possibility of repositioning or removing the device was an advantage. The higher attenuation may lead to fewer devices per case and early aneurysm occlusion. Long-term follow-up data are pending.

Functional imaging: where do we go from here?

As highly invasive and infiltrative tumors, gliomas are hard to delineate from healthy brain parenchyma, even with the microscope enhanced eye of an experienced neurosurgeon. However, the surgical goal remains maximum extent of tumor volume resection with a preservation of neurological function. With functional data integrated and visualized in the navigation system, postoperative morbidity can be reduced. With the so far well established techniques diffusion-tensor-imaging (DTI) based fiber tractography and functional MRI (fMRI), white matter tracts or eloquent cortical areas can be displayed. With magnetic resonance spectroscopy (MRS) and also positron emmission computed tomography (PET), methods displaying brain metabolism are also widely used. However, further technical and computational development of these methods has already shown extended insights in brain networks and pathologies and promises further reduction of postoperative morbidity, while used in navigation systems. In addition to these methods, novel techniques have already been implemented and successfully used in the clinical routine. In this way, this review summarizes recent developments in DTI, fMRI, MRSI and PET, also with their use during neurosurgical operations, but also gives introduction in novel methods like navigated transcranial magnetic stimulation (nTMS) or advanced diffusion models as base for fiber tracking.

[Improved magnetic resonance myelography using image fusion]

PURPOSE

To demonstrate that the disadvantage of missing anatomical information in heavily T2-weighted MR myelography images can be eliminated by image fusion and phase encoding in the coronal direction of the source images, resulting in MR myelography images comparable to the gold standard, i. e., post-myelography CT.

MATERIALS AND METHODS

This study included 110 patients suffering from extradural pathologies of the cervical and lumbar spine. All patients were investigated using 3D MR myelography and post-myelography CT. The MRI data were post-processed using image fusion and reconstruction algorithms and were compared to the corresponding images of post-myelography CT.

RESULTS

Our approach for visualization (3D MR myelography) was able to depict intradural structures in high spatial resolution and without artifacts. The results of our visualization approach were comparable to the gold standard - post-myelography CT. Anatomical correlation was reached by image fusion of different MR data sets. The required post-processing steps were performed quickly and were available on a commercial workstation.

CONCLUSION

Image fusion of different MR data sets allows for visualization of 3D data sets with enhanced quality. The results for the visualization of MR myelography in particular are comparable to conventional myelography and post-myelography CT. The missing anatomical information in heavily T2-weighted MR myelography images can be compensated by image fusion with conventional MRI.

Angiographic CT with intravenous contrast injection compared with conventional rotational angiography in the diagnostic work-up of cerebral aneurysms

BACKGROUND AND PURPOSE

Noninvasive imaging of cerebral aneurysms is still considered inferior to conventional angiography. The purpose of this study was to evaluate the diagnostic accuracy of ivACT in the assessment of intracranial aneurysms compared with 3D-DSA.

MATERIALS AND METHODS

We included 13 patients with 15 incidental unruptured saccular aneurysms scheduled for diagnostic angiographic work-up in our study. In each patient, we performed an ivACT and a conventional angiography including a 3D rotational run. During postprocessing, MPR images were generated for each technique. Maximal aneurysm diameter, neck diameter, aneurysm height, maximum width, bulge height, parent artery diameter, and angle between the parent artery and aneurysm apex were measured for each aneurysm.

RESULTS

3D-DSA and ivACT both provided images of high quality without artificial disturbances (ie, motion artifacts). Measurements of all parameters resulted in comparable values for both modalities with a strong correlation (P ≤ .001).

CONCLUSIONS

ivACT is feasible for the noninvasive visualization of saccular cerebral aneurysms and may provide reliable diagnostic information for the assessment of aneurysm size and geometry comparable with conventional intra-arterial 3D rotational angiography. These preliminary results might be a first promising step to replacing conventional angiography in preinterventional aneurysm imaging.

[Papilledema and echographically detectable retro-orbital dilatation of the sub-arachnoidal space with open fontanelle - six case reports]

This paper analyses the case reports for three children in which a papilledema occurred before the age of one year. Furthermore, an analysis is also given of three further case reports for children aged less than one year in which, in spite of open fontanelle, no papilledema was found, however, a dilatation of the sub-arachnoidal space was demonstrated echographically. Even in children less than one year of age in which an open fontanelle still exists and in whom a neuro-paediatric clarification of internal hydrocepalus is made, in spite of opththalmoscopically inconspicuous findings for the papilla an echography is indispensable for the evaluation of the sub-arachnoidal space. Here, the early recognition of a dilatation of the retro-bulbar sub-arachnoidal space can possibly prevent the occurrence of a consecutive optic atrophy. At the present time, the data available do not allow the recommendation of an upper age limit for an echographic examination.

Magnetic resonance spectroscopic imaging for visualization of the infiltration zone of glioma

BACKGROUND AND PURPOSE

In conventional MR imaging, it is often difficult to delineate the heterogeneous structure of gliomas. Proton magnetic resonance spectroscopic imaging ((1)H-MRSI) is a noninvasive tool for investigating the spatial distribution of metabolic changes in brain lesions. The aim of this study was to assess the improvements in delineation of gliomas based on segmentation of metabolic changes measured with (1)H-MRSI.

MATERIAL AND METHODS

Twenty patients with gliomas (WHO grade II and III) were examined using a standard (1)H-MRSI sequence. Metabolic maps for choline (Cho), N-acetyl-aspartate (NAA) and Cho/NAA ratios were calculated and segmented based on the assumption of a Gaussian distribution of the Cho/NAA values for normal brain. Areas of hyperintensity on T2-weighted (T2w) MR images were compared with the areas of the segmented tumor on Cho/NAA maps. Stereotactic biopsies were obtained from the MRSI/T2w difference areas.

RESULTS

In all patients, the segmented MRSI tumor areas were greater than the T2w hyperintense areas, on average, by 20% (range 6-34%). In nine patients, biopsy sampling from the MRSI/T2w difference areas showed tumor infiltration ranging from 4-17% (mean 9%) tumor cells, in the areas detected only by MRSI.

DISCUSSION AND CONCLUSION

Our method for automated segmentation of the lesion-related metabolic changes achieved significantly improved delineation for gliomas compared to routine clinical methods. We demonstrate that this method can improve delineation of tumor borders compared to routine imaging strategies in clinics. Metabolic images of the segmented tumor may thus be helpful for therapeutic planning.

Single versus bilateral external ventricular drainage for intraventricular fibrinolysis in severe ventricular haemorrhage

BACKGROUND

Intraventricular fibrinolysis (IVF) through bilateral external ventricular drains (EVD) may provide better access of the thrombolytic agent to the intraventricular clot, potentially influencing clot clearance and outcome.

METHODS

Patients with spontaneous ganglionic intracerebral haemorrhage (ICH)<40 cm(3) and intraventricular haemorrhage (IVH) with acute hydrocephalus have been treated with IVF. The decision for placement of one or two EVDs has been left to the discretion of the treating physician. CT volumetry, the effects on cerebrospinal fluid (CSF) circulation and outcome at 3 months have been analysed for patients with one (group I, n = 13) or two EVDs (group II, n = 14).

RESULTS

No difference was found in clot resolution between the two groups (clot half life 2.1 (SD 1.2) vs 2.4 (1.3) days). A separate analysis of the third and fourth ventricle clearance was similar (1.6 (0.6) versus 1.8 (0.8) days), indicating no difference in reconstitution of CSF circulation. A trend towards a longer EVD duration and higher infection rate was found in the bilateral EVD group. No difference was found in outcome at 3 months.

CONCLUSIONS

Our results do not support the use of bilateral EVDs for IVF in patients with severe IVH.

Aplasia cutis congenita--plastic reconstruction of three scalp and skull defects with two opposed scalp rotation flaps and split thickness skin grafting

Aplasia cutis congenita (ACC) is a rare congenital defect of skin and subcutaneous tissue, more rarely of periosteum, skull and dura. The lesions can involve any location, but most common are scalp defects. We report on the successful treatment of three large defects of the scalp with skull involvement in a newborn girl by early debridement and defect closure with two opposed scalp rotation flaps and an occipital split-thickness skin graft.

In vivo quantification of intracerebral GABA by single-voxel (1)H-MRS-How reproducible are the results?

Gamma aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the human brain. It plays a decisive role in a variety of nervous system disorders, such as anxiety disorders, epilepsy, schizophrenia, insomnia, and many others. The reproducibility of GABA quantification results obtained with a single-voxel spectroscopy J-difference editing sequence with Point Resolved Spectroscopy localization (MEGA-PRESS) was determined on a 3.0 Tesla MR scanner in healthy adults. Eleven volunteers were measured in long- and short-term intervals. Intra- and inter-subject reproducibility were evaluated. Internal referencing of GABA+ to total creatine (tCr) and water (H(2)O), as well as two different post-processing methods for the evaluation (signal integration and time-domain fitting) were compared. In all subjects lower coefficient of variation and therefore higher reproducibility can be observed for fitting compared to integration. The GABA+/tCr ratio performs better than the GABA+/H(2)O ratio or GABA+ without internal referencing for both fitting and integration (GABA+/tCr: 13.3% and 17.0%; GABA+/H(2)O: 15.0% and 17.8%; GABA+: 19.2% and 21.7%). Four-day measurements on three subjects showed higher intra- than inter-subject reproducibility (GABA+/tCr approximately 10-12%). With a coefficient of variation of about 13% for inter-subject and 10-12% for intra-subject variability of GABA+/tCr, this technique seems to be a precise tool that can detect GABA confidently. The results of this study show the reproducibility limitations of GABA quantification in vivo, which are necessary for further clinical studies.

Hemorrhage into cystic vestibular schwannoma following stereotactic radiation therapy

The occurrence of a hemorrhage into a vestibular schwannoma is a rare phenomenon. Several reports, however, indicate a risk profile for a subgroup of patients with vestibular schwannoma which show hypervascularity in the histopathological examination. Cystic formation, large size, mixed Antoni type and anticoagulation therapy seem to enhance the risk of tumor hemorrhage. We report on a patient with a large cystic vestibular schwannoma who died from fatal bleeding into the tumor 15 months following stereotactic radiation therapy. Since hemorrhage seems to be a relevant risk in large cystic vestibular schwannomas, a surgical treatment should be preferred whenever possible.

Flat panel detector angiographic CT in the management of aneurysmal rupture during coil embolization

Angiographic CT (ACT) produces CT-like images within minutes in the angiography suite. We present the cases of 2 patients with intraprocedural aneurysmal rupture in which ACT enabled the neuroradiologist to rapidly assess the extent of bleeding during endovascular treatment. Additionally, ACT revealed pronounced rebleeding within the time between conventional CT and onset of treatment. In the management of aneurysmal rupture during coil embolization, ACT may be a valuable adjunct.

Flat panel detector angiographic CT for stent-assisted coil embolization of broad-based cerebral aneurysms

BACKGROUND AND PURPOSE

The purpose of this work was to evaluate angiographic CT (ACT) in the combined application of a self-expanding neurovascular stent and detachable platinum coils in the management of broad-based and fusiform intracranial aneurysms.

MATERIALS AND METHODS

Eleven patients harboring wide-necked intracranial aneurysms were treated with a flexible self-expanding neurovascular stent and subsequent aneurysm embolization with platinum microcoils. ACT was performed after the interventional procedure to analyze stent position and the relationship of coils to the stent. Postprocessing included multiplanar reconstructions (MPRs) and maximum intensity projections (MIPs). ACT volume datasets were postprocessed for soft tissue visualization.

RESULTS

Accurate stent placement with subsequent coil occlusion of the aneurysms was feasible in all of the patients. Similar to nonsubtracted digital subtraction angiography (DSA) images, radiopaque platinum stent markers showed excellent visibility in ACT as well. The stent struts themselves, hardly visible in nonsubtracted DSA, were visible in MPRs and MIPs of ACT in all of the patients. In aneurysms larger than 10 mm in diameter, accurate stent assessment at the level of the coils was limited due to beam hardening artifacts. Postprocedural ACT in all of the patients did not reveal any evidence of procedure-related intracranial hemorrhage.

CONCLUSION

ACT provides cross-sectional, 3D visualization of endovascular stents otherwise hardly visible with plain fluoroscopy. ACT enables us to accurately determine stent position, which may be helpful in complex stent-assisted aneurysm coiling procedures. However, in aneurysms larger than 10 mm in diameter, beam hardening artifacts caused by the endoaneurysmal coil package impair visibility of the stent. Further data are necessary to evaluate the usefulness of ACT in stent-assisted aneurysm coiling.

Diffusion tensor imaging and white matter tractography in patients with brainstem lesions

BACKGROUND

Diffusion tensor imaging (DTI) and white matter tractography (WMT) are promising techniques for estimating the course, extent, and connectivity patterns of the white matter (WM) structures in the human brain. In this study, we investigated the ability of DTI and WMT to visualize white matter tract involvement for the preoperative surgical planning and postoperative assessment of brainstem lesions.

METHODS

Preoperative and postoperative DTI data (echo-planar, 1.5T) were retrospectively analyzed in 10 patients with brainstem lesions (3 diffuse, 7 focal). WMT applying a tensor deflection algorithm was used to reconstruct WM tracts adjacent to the lesions. Reconstructed tracts included corticospinal tracts and medial lemnisci. The clinical and imaging follow-up data were also compared and analyzed.

FINDINGS

WMT revealed a series of tract alteration patterns including deviation, deformation, infiltration, and apparent tract interruption. WMT reconstructions showed that the major WM tracts were preserved during surgery and improved in position and appearance postoperatively. These findings correlated with the improvement or preservation of neurological function as determined by clinical assessment.

CONCLUSIONS

Compared with the information provided by conventional MR imaging, DTI and WMT provided superior quantification and visualization of lesion involvement in eloquent fibre tracts of the brainstem. Moreover, DTI and WMT were found to be beneficial for white matter recognition in the neurosurgical planning and postoperative assessment of brainstem lesions.

Changes in fiber integrity, diffusivity, and metabolism of the pyramidal tract adjacent to gliomas: a quantitative diffusion tensor fiber tracking and MR spectroscopic imaging study

BACKGROUND AND PURPOSE

The underlying changes in the neuronal connectivity adjacent to brain tumors cannot always be depicted by conventional MR imaging. The hypothesis of this study was that preoperative sensorimotor deficits are associated with impairment in pyramidal fiber bundles. Hence, we investigated the potential of combined quantitative diffusion tensor (DT) fiber tracking and MR spectroscopic imaging (MRSI) to determine changes in the pyramidal tract adjacent to gliomas.

MATERIALS AND METHODS

Quantitative DT fiber tracking and proton MRSI were performed in 20 patients with gliomas with WHO grades II-IV. Eight patients experienced preoperative sensorimotor deficits. Mean diffusivity (MD), fractional anisotropy (FA), and number of fibers per voxel (FpV) were calculated for the pyramidal tract of the ipsilateral and contralateral hemisphere. Metabolite concentrations for choline-containing compounds (Cho), creatine (Cr), and N-acetylaspartate (NAA) were computed, using LCModel, for all voxels located at the pyramidal tracts.

RESULTS

For the whole pyramidal tract, quantitative DT fiber tracking resulted in significantly lower FpV and FA values (P < .001), but not MD values, for the ipsilateral hemisphere. For the section of the fiber bundle closest to the lesion, we found significantly decreased FpV and FA (P < .001) and increased MD (P = .002). MRSI showed, for the same volumes of interest, significantly decreased NAA (P = .001), increased Cho (P = .034) and Cho/NAA (P = .001) for the ipsilateral pyramidal tract. In patients suffering sensorimotor deficits, we found significantly lower FA (P = .022) and higher MD values (P = .026) and a strongly negative correlation between FA and MD (R = -0.710, P = .024) but no correlation in patients without deficits (R = 0.078, ns).

CONCLUSION

Quantitative DTI was able to show significant differences in diffusivity of the pyramidal tract in patients with sensorimotor deficits in relation to patients without them. The additional use of proton MRSI may be helpful to discern whether these diffusivity changes in fiber tracts are caused by tumor infiltration or peritumoral edema.

Multimodal coregistration in patients with temporal lobe epilepsy--results of different imaging modalities in lateralization of the affected hemisphere in MR imaging positive and negative subgroups

BACKGROUND AND PURPOSE

In this study, intensive video electroencephalogram (EEG) monitoring, high-resolution MR imaging (MR imaging), proton MR spectroscopy ((1)H-MR spectroscopy) and single-photon emission CT (SPECT) were compared in patients with temporal lobe epilepsy (TLE) to evaluate lateralization of affected hemisphere with regard to bilateral affection and postoperative outcome.

PATIENTS AND METHODS

Recall ratio of each technique for indicating the affected hemisphere was determined in 49 patients with TLE. Postoperative outcome was established by Engel classification.

RESULTS

Twenty-two of 25 patients with TLE with evidence for hippocampal sclerosis in MR imaging (MR imaging-positive) were graded as unilateral by EEG findings whereas 3 were classified as bilateral. Fourteen of 24 MR imaging-negative patients were graded as unilateral by EEG and 10 as bitemporal. (1)H-MR spectroscopy indicated concordant lateralization to EEG in 82% of MR imaging-positive patients and 71% of MR imaging-negative patients and to SPECT in 84% of MR imaging-positive patients and 67% of MR imaging-negative patients with TLE. In unilateral TLE, the concordance rate of both modalities was 74% in MR imaging-positive patients and 67% in MR imaging-negative patients. Contralateral findings to EEG focus were found in 28% by (1)H-MR spectroscopy and in 27% by SPECT. Concordant findings to the operated side of different modalities revealed a clear tendency (P = .08) for a better postoperative outcome compared with bitemporal or contralateral findings.

CONCLUSION

Our data demonstrate that multimodal imaging in patients with TLE improves lateralization of affected hemispheres, especially in patients without pathologic findings in MR imaging, and indicates bilateral effect, which is important to identify patients who will benefit from surgery.