The utility of dual-energy computed tomography angiography for the evaluation of brain aneurysms after endovascular coiling: a prospective study.

BACKGROUND: Non-invasive alternatives to digital subtraction angiography (DSA) for follow-up of patients with coiled aneurysms are sought. PURPOSE: To compare a novel method of dual-energy computed tomography angiography (DE-CTA) for postoperative assessment of coiled brain aneurysms to detect aneurysm recanalization and patency of adjacent blood vessels, with DSA. MATERIAL AND METHODS: Patients who underwent endovascular cerebral aneurysm coiling were prospectively evaluated postoperatively by both DE-CTA and conventional DSA. CTA was performed using a novel dual-energy method with single-source and fast kilovoltage switching. DSA was performed using biplanar cerebral angiography. An experienced neuroradiologist and neurosurgeon, both blinded to the original radiological results, reviewed the images. RESULTS: A total of 54 patients (16 men, 38 women; mean age=47.6 + 9 years) with 55 coiled aneurysms were enrolled in our study between July 2014 and June 2015: 29 patients had suffered a subarachnoid hemorrhage and 26 patients had an incidentally found cerebral aneurysm. All patients had at least one DSA and DE-CTA performed at most one week apart. DE-CTA showed a 100% sensitivity and specificity in detection of complete aneurysm occlusion and 80% sensitivity and specificity for detection of residual necks and domes. DE-CTA successfully detected all vascular diameter changes as comparable to DSA with minimal interfering artifact. CONCLUSION: DE-CTA is a promising non-invasive alternative to conventional catheter-based angiography for identification of aneurysm recurrence and assessment of adjacent arteries after endovascular coiling. It allows for far more rapid image acquisition than DSA, is non-invasive, and is widely available at clinical centers.

Masson Tumor of the Central Nervous System: A Case Report and Review of Literature.

BACKGROUND Masson's tumor, also known as intravascular papillary endothelial hyperplasia (IPEH), is an unusual endothelial proliferation that leads to improper thrombus development due to faulty endothelial structure. Although IPEH is rare in the central nervous system, it can arise at any location in the brain. Headaches, seizures, and focal neurological symptoms ae the most common presenting symptoms. It is more common in females and it can occur at any age. CASE REPORT Herein, we present a 65-year-old female patient with a progressively enlarging right temporal lobe mass that was initially considered metastatic ovarian carcinoma. She underwent a right temporal craniotomy and the lesion was totally resected. Contrary to expectations, the pathology report was an IPEH. CONCLUSIONS In this paper, we conducted a literature review of previously reported cerebral IPEH cases, with a focus on their clinical and radiological presentations, management, and especially their association with previous radiotherapy. The important point is that one-third of the cases had a history of radiation therapy to the head, and most of them had stereotactic radiosurgery (SRS) on the location of the brain from which IPEH subsequently developed. The major question for which we are looking for an answer is its relationship with previous radiotherapies. We wanted to know how many of these cases were associated with radiotherapy in the same area, the time interval from radiotherapy to the onset of IPEH or symptoms, the dose of the previous radiotherapy, and, overall, if there is any cause-effect relationship between IPEH and radiotherapy.

Aneurysms of the external carotid artery and its branch vessels: pooled data analysis and current treatment strategies.

INTRODUCTION: Aneurysms of the external carotid artery (ECA) and its branch vessels are rare vascular lesions with potentially devastating consequences. Proximal facial artery aneurysms are relatively uncommon. We provide a provide a pooled data analysis of all reported cases of proximal facial artery true aneurysms without evidence of trauma, as well as all published cases of aneurysms and pseudoaneurysms of the ECA and its branch vessels. EVIDENCE ACQUISITION: We conducted a systematic review of the literature searching multiple databases for reports to identify relevant papers. EVIDENCE SYNTHESIS: We report the case of a 63-year-old patient who presented to us with a digital subtraction angiography-confirmed aneurysm emanating from the proximal right facial artery with no apparent history of trauma. Only five cases of proximal facial artery true aneurysm have been reported without evidence of trauma. We also provide a pooled data analysis of 810 published cases of aneurysms and pseudoaneurysms of the ECA and its branch vessels. Moreover, we reviewed current treatment strategies and surgical approaches to the true and pseudo aneurysms of the ECA. Finally, we suggest a grading system and treatment protocol for theses aneurysms. Finally, we provided a comprehensive grading system for the management of these aneurysms. CONCLUSIONS: While we can follow small asymptomatic true ECA aneurysms, pseudoaneurysms of the ECA and its branches, once diagnosed, may require treatment to prevent rapid expansion, which may in turn lead to rupture, cranial nerve impingement, pain, or cosmetic disfigurement.

Frameless Stereotactic Navigation during Insular Glioma Resection using Fusion of Three-Dimensional Rotational Angiography and Magnetic Resonance Imaging.

BACKGROUND: Perioperative cerebral infarction is a potential complication of glioma resection, of which insular tumors are at higher risk because of the proximity of middle cerebral artery branches, including the lateral lenticulostriates and long insular arteries. In this study, 3 patients received three-dimensional rotational angiography, which was fused with magnetic resonance imaging (MRI) for frameless stereotactic navigation during dominant-hemisphere insular glioma resection. METHODS: All patients obtained a preoperative catheter angiogram with a three-dimensional rotational acquisition of the ipsilateral internal carotid artery. The pixel-based axial three-dimensional angiography data, thin-cut structural MRI, tractography from diffusion tensor imaging, and expressive language activation from functional MRI were uploaded into the iPlan software (Brainlab, Heimstetten, Germany) and fused. The target tumor, regional blood vessels, adjacent functional areas, and their associated fiber tracts were segmented and overlaid on the appropriate MRI sequence. This image fusion was used preoperatively to visualize the relationship of the mass with the adjacent vasculature and intraoperatively for frameless stereotactic navigation to optimize preservation of arterial structures. RESULTS: Three patients aged 27-60 years with excellent baseline functional status presented with seizures and were found to have a large dominant-hemisphere T2 hyperintense nonenhancing insular mass. Surgical resection was performed using multimodality neuronavigation. None sustained a postoperative arterial infarction or a perioperative neurologic deficit. CONCLUSIONS: Neuronavigation using a fusion of three-dimensional rotational angiography with MRI is a technique that can be used for preoperative planning and during resection of insular gliomas to optimize preservation of adjacent arteries.

Brain Computed Tomography Angiography as an Ancillary Test in the Confirmation of Brain Death.

Introduction Brain death (BD) is the irreversible termination of the functioning of the brain. The diagnosis should be first made by clinical criteria and confirmed by using paraclinical confirmatory techniques (ancillary tests). While conventional brain angiography remains the standard method of choice, computed tomography angiography (CTA) has emerged as an alternative method. In this study, we tried to evaluate the accuracy of CTA for the diagnosis of BD. Methods In this study, we included nine patients with a clinical diagnosis of BD, confirmed by electroencephalography (EEG). CTA was then performed to compare the results. Results The most frequent cause for BD was multiple trauma (7/9) in our patients, followed by aneurysm rupture and brain infarct. CTA examination in all patients showed opacification of extracranial arteries and major branches of external carotid artery (ECA), including superficial temporal arteries (STAs), while no opacification was observed in the internal carotid arteries (ICA) including and beyond the cavernous segment, middle cerebral arteries (MCAs), anterior cerebral arteries (ACAs), distal vertebral arteries (VAs), and basilar artery (BA). Moreover, no opacification was observed in the internal cerebral veins (ICVs) or great cerebral vein (GCV). Conclusion The accuracy rate of CTA in the detection of intracranial circulatory arrest was 100%. CTA examinations confirmed BD diagnoses in all patients who had clinical and EEG BD diagnoses, and no confliction between CTA findings and clinical diagnoses was observed.

Flow and pressure measurements in aneurysms and arteriovenous malformations with phase contrast MR imaging.

PURPOSE: To explore phase contrast (PC) magnetic resonance imaging of aneurysms and arteriovenous malformations (AVM). PC imaging obtains a vector field of the velocity and can yield additional hemodynamic information, including: volume flow rate (VFR) and intravascular pressure. We expect to find lower VFR distal to aneurysms and higher VFR in vessels of the AVM. MATERIALS AND METHODS: Five cerebral aneurysm and three AVM patients were imaged with PC techniques and compared to VFR of a healthy cohort. VFR was calculated in vessel segments in each patient and compared statistically to the healthy cohort by computing the z-score. Intravascular pressure was calculated in the aneurysms and in the nidus of each AVM. RESULTS: We found that patients with aneurysm had z<-0.48 in vessels distal to the aneurysm (reduced flow), while AVM patients had z>6 in some vessels supplying and draining the nidus (increased flow). Pressures in aneurysms were highly variable between subjects and location, while in the nidus of the AVM patients; pressure trended higher in larger AVMs. CONCLUSION: The study findings confirm the expectation of lower distal flow in aneurysm and higher arterial and venous flow in AVM patients.

Multimodal Navigation in Endoscopic Transsphenoidal Resection of Pituitary Tumors Using Image-Based Vascular and Cranial Nerve Segmentation: A Prospective Validation Study.

BACKGROUND: Transsphenoidal surgery (TSS) is the most common approach for the treatment of pituitary tumors. However, misdirection, vascular damage, intraoperative cerebrospinal fluid leakage, and optic nerve injuries are all well-known complications, and the risk of adverse events is more likely in less-experienced hands. This prospective study was conducted to validate the accuracy of image-based segmentation coupled with neuronavigation in localizing neurovascular structures during TSS. METHODS: Twenty-five patients with a pituitary tumor underwent preoperative 3-T magnetic resonance imaging (MRI), and MRI images loaded into the navigation platform were used for segmentation and preoperative planning. After patient registration and subsequent surgical exposure, each segmented neural or vascular element was validated by manual placement of the navigation probe or Doppler probe on or as close as possible to the target. RESULTS: Preoperative segmentation of the internal carotid artery and cavernous sinus matched with the intraoperative endoscopic and micro-Doppler findings in all cases. Excellent correspondence between image-based segmentation and the endoscopic view was also evident at the surface of the tumor and at the tumor-normal gland interfaces. Image guidance assisted the surgeons in localizing the optic nerve and chiasm in 64% of cases. The mean accuracy of the measurements was 1.20 ± 0.21 mm. CONCLUSIONS: Image-based preoperative vascular and neural element segmentation, especially with 3-dimensional reconstruction, is highly informative preoperatively and potentially could assist less-experienced neurosurgeons in preventing vascular and neural injury during TSS. In addition, the accuracy found in this study is comparable to previously reported neuronavigation measurements. This preliminary study is encouraging for future prospective intraoperative validation with larger numbers of patients.

Abnormal Large Central Occipital Emissary Vein: A Case Report and Review of Literature.

A detailed description of the anatomy of the central occipital emissary vein, its embryology, anatomy, and abnormal variations is not available in the literature. This is the first known case report. A 48-year-old female underwent cerebral angiography to rule out dural arterio-venous fistula. Her angiography revealed an abnormally large central occipital emissary vein originating from the torcula, penetrating the cranium and draining into the suboccipital venous plexus. We provide discussion of the case with a review of the related literature. This case and its attached radiological images introduce a new type of entity to the existing data about the cranial emissary veins.

Application of Pipeline Embolization Device for Iatrogenic Pseudoaneurysms of the Extracranial Vertebral Artery: A Case Report and Systematic Review of the Literature.

Traumatic pseudoaneurysms of the vertebral artery (VA) are uncommon vascular lesions and definitive management is often challenging. Between 0% and 8% of craniocervical fusions are complicated by VA injury. In these cases, preserving the vertebral artery while treating the pseudoaneurysm is the goal of any treatment option. We describe the second known case of a patient with and iatrogenic extracranial vertebral artery pseudoaneurysm treated effectively using the Pipeline Embolization Device (PED) (Ev3 Neurovascular, Irvine, CA). Although there have been only two cases reported, the use of flow-diverting stents appears to be efficacious for the treatment of non-actively bleeding traumatic pseudoaneurysms.

Multimodal navigated skull base tumor resection using image-based vascular and cranial nerve segmentation: A prospective pilot study.

BACKGROUND: Skull base tumors frequently encase or invade adjacent normal neurovascular structures. For this reason, optimal tumor resection with incomplete knowledge of patient anatomy remains a challenge. METHODS: To determine the accuracy and utility of image-based preoperative segmentation in skull base tumor resections, we performed a prospective study. Ten patients with skull base tumors underwent preoperative 3T magnetic resonance imaging, which included thin section three-dimensional (3D) space T2, 3D time of flight, and magnetization-prepared rapid acquisition gradient echo sequences. Imaging sequences were loaded in the neuronavigation system for segmentation and preoperative planning. Five different neurovascular landmarks were identified in each case and measured for accuracy using the neuronavigation system. Each segmented neurovascular element was validated by manual placement of the navigation probe, and errors of localization were measured. RESULTS: Strong correspondence between image-based segmentation and microscopic view was found at the surface of the tumor and tumor-normal brain interfaces in all cases. The accuracy of the measurements was 0.45 ± 0.21 mm (mean ± standard deviation). This information reassured the surgeon and prevented vascular injury intraoperatively. Preoperative segmentation of the related cranial nerves was possible in 80% of cases and helped the surgeon localize involved cranial nerves in all cases. CONCLUSION: Image-based preoperative vascular and neural element segmentation with 3D reconstruction is highly informative preoperatively and could increase the vigilance of neurosurgeons for preventing neurovascular injury during skull base surgeries. Additionally, the accuracy found in this study is superior to previously reported measurements. This novel preliminary study is encouraging for future validation with larger numbers of patients.

Pre-operative image-based segmentation of the cranial nerves and blood vessels in microvascular decompression: Can we prevent unnecessary explorations?

OBJECTIVES: This study was conducted to validate the accuracy of image-based pre-operative segmentation using the gold standard endoscopic and microscopic findings for localization and pre-operative diagnosis of the offensive vessel. PATIENTS AND METHODS: Fourteen TN and 6 HS cases were randomly selected. All patients had 3T MRI, which included thin-sectioned 3D space T2, 3D Time of Flight and MPRAGE Sequences. Imaging sequences were loaded in BrainLab iPlanNet and fused. Individual segmentation of the affected cranial nerves and the compressing vascular structure was performed by a neurosurgeon, and the results were compared with the microscopic and endoscopic findings by two blinded neurosurgeons. For each case, at least three neurovascular landmarks were targeted. Each segmented neurovascular element was validated by manual placement of the navigation probe over each target, and errors of localization were measured in mm. RESULTS: All patients underwent retro-sigmoid craniotomy and MVD using both microscope and endoscope. Based on image segmentation, the compressing vessel was identified in all cases except one, which was also negative intraoperatively. Perfect correspondence was found between image-based segmentation and endoscopic and microscopic images and videos (Dice coefficient of 1). Measurement accuracy was 0.45 ± 0.21 mm (mean ± SD). CONCLUSION: Image-based segmentation is a promising method for pre-operative identification and localization of offending blood vessels causing HFS and TN. Using this method may prevent some unnecessary explorations on especially atypical cases with no vascular contacts. However, negative pre-operative image segmentation may not preclude one from exploration in classic cases of TN or HFS. A multicenter study with larger number of cases is recommended.

The Frequency of Subarachnoid Hemorrhage from Very Small Cerebral Aneurysms (< 5 mm): A Population-Based Study.

BACKGROUND:  The prevailing view amongst neurosurgeons is that the larger the aneurysm, the higher the chance of rupture. This implies that very small aneurysms rarely rupture. To investigate this theory, we conducted a cross-sectional hospital-based study of aneurysmal subarachnoid hemorrhage, with an emphasis on aneurysm size at the time of rupture. METHODS:  We retrospectively reviewed hospital records and radiological tests of all patients admitted to Foothills Medical Center, Calgary, Alberta, with a ruptured saccular aneurysm from January 2008 to January 2012. The size of the dome and neck (in millimeters), the aspect ratio (aneurysm depth to aneurysm neck), and location of the aneurysms were determined using preoperative computed tomography angiography and digital subtraction angiography. FINDINGS:  One hundred and twenty-three patients with a ruptured saccular aneurysm were identified. The average size of the dome, neck, and the aspect ratio was 6.6±4.4 mm (range: 1.5-26 mm), 3.1 mm, and 2.6±0.9, respectively. Forty-six patients (37%) had a ruptured aneurysm with dome size < 5 mm (range: 1.5-4.9 mm). For these small aneurysms, the average size of the dome, neck, and the aspect ratio was 3.9+1.1 mm, 1.6 mm, and 2.1+0.6, respectively. The anterior communicating artery was the most common location regardless of size. CONCLUSION:  Small aneurysms (< 5 mm) are a common cause of aneurysmal subarachnoid hemorrhage. When unruptured, looking for other risk factors for rupture is highly recommended before simply leaving them alone.

The Utility of Dual-Energy Computed Tomographic Angiography for the Evaluation of Brain Aneurysms After Surgical Clipping: A Prospective Study.

OBJECTIVE: The purpose of this prospective study was to compare a novel dual-energy computed tomographic angiography (DECTA) method for postoperative assessment of clipped brain aneurysms to detect aneurysm remnants and parent artery patency, with catheter-based digital subtraction angiography (DSA). METHODS: Patients who underwent microsurgical cerebral aneurysm repair were prospectively evaluated after surgery by both DECTA and conventional DSA. CTA was performed using a novel dual-energy method with single source and fast kilovoltage switching (Gemstone Spectral Imaging [GSI]). DSA was performed using biplanar cerebral angiography. An experienced neuroradiologist and a neurosurgeon, both blinded to the original radiologic results, reviewed the images. RESULTS: On DSA, 8 of 15 aneurysms (53%) had a remnant after clipping. All of these remnants were <2 mm except for 1. The only residual aneurysm >2 mm was clearly detected by GSI CTA. Of those 7 DSA-confirmed <2-mm remnants, 5 were detected by GSI CTA. Metal artifacts compromised the image quality in 2 patients. The sensitivity and specificity of GSI CTA for remnant aneurysm <2-mm detection in single clip-treated patients were 100%. In all patients, these were 71.4 % and 100%, respectively. GSI CTA was 100% sensitive and 77% specific to detect parent vessel compromise, with associated positive and negative predictive values of 60% and 100%, respectively. CONCLUSIONS: DECTA is a promising noninvasive alternative to conventional catheter-based angiography for identification of aneurysm remnants and assessment of adjacent arteries after surgical clipping of brain aneurysms treated by 2 or fewer clips. It allows for a more rapid image acquisition than DSA, is more cost effective, and is widely available at clinical centers.

Intraoperative Magnetic Resonance Imaging in Intracranial Glioma Resection: A Single-Center, Retrospective Blinded Volumetric Study.

BACKGROUND: Intraoperative magnetic resonance imaging (IoMRI) was devised to overcome brain shifts during craniotomies. Yet, the acceptance of IoMRI is limited. OBJECTIVE: To evaluate impact of IoMRI on intracranial glioma resection outcome including overall patient survival. METHODS: A retrospective review of records was performed on a cohort of 164 consecutive patients who underwent resection surgery for newly diagnosed intracranial gliomas either with or without IoMRI technology performed by 2 neurosurgeons in our center. Patient follow-up was at least 5 years. Extent of resection (EOR) was calculated using pre- and postoperative contrast-enhanced and T2-weighted MR-images. Adjusted analysis was performed to compare gross total resection (GTR), EOR, permanent surgery-associated neurologic deficit, and overall survival between the 2 groups. RESULTS: Overall median EOR was 92.1%, and 97.45% with IoMRI use and 89.9% without IoMRI, with crude (unadjusted) P < 0.005. GTR was achieved in 49.3% of IoMRI cases, versus in only 21.4% of no-IoMRI cases, P < 0.001. GTR achieved was more with the use of IoMRI among gliomas located in both eloquent and noneloquent brain areas, P = 0.017 and <0.001, respectively. Permanent surgery-associated neurologic deficit was not (statistically) more significant with no-IoMRI, P = 0.284 (13.8% vs. 6.7%). In addition, the IoMRI group had better 5-year overall survival, P < 0.001. CONCLUSION: This study shows that the use of IoMRI was associated with greater rates of EOR and GTR, and better overall 5-year survival in both eloquent brain areas located and non-eloquent brain areas located gliomas, with no increased risk of neurologic complication.

Hemodynamic alterations measured with phase-contrast MRI in a giant cerebral aneurysm treated with a flow-diverting stent.

Many risk factors have been proposed in the development of the cerebral aneurysms. Hemodynamics including blood velocity, volume flow rate (VFR), and intravascular pressure are thought to be prognostic indicators of aneurysm development. We hypothesize that treatment of cerebral aneurysm using a flow-diverting stent will bring these hemodynamic parameters closer to those observed on the contralateral side. In the current study, a patient with a giant cerebral aneurysm was studied pre- and postoperatively using phase contrast MRI (PC-MRI) to measure the hemodynamic changes resulting from the deployment of a flow-diverting stent. PC-MRI was used to calculate intravascular pressure, which was compared to more invasive endovascular catheter-derived measurements. After stent placement, the measured VFRs in vessels of the treated hemisphere approached those measured on the contralateral side, and flow symmetry changed from a laterality index of -0.153 to 0.116 in the middle cerebral artery. Pressure estimates derived from the PC-MRI velocity data had an average difference of 6.1% as compared to invasive catheter transducer measurements. PC-MRI can measure the hemodynamic parameters with the same accuracy as invasive methods pre- and postoperatively.

Controversy in the management of lenticulostriate artery dissecting aneurysm: a case report and review of the literature.

BACKGROUND: Intracranial arterial dissection is an uncommon but well-recognized entity. Treatment remains variable, ranging from observation to intervention via the use of either surgical or endovascular techniques. Aneurysms along the lenticulostriate artery have been reported in only 41 patients. With the current case study we illustrate the effectiveness of observation in the context of a dissecting lenticulostriate aneurysm and discuss other approaches that have been used in the treatment of this particular entity. CLINICAL SUMMARY: An accomplished mountain climber presented, after coitus, with acute headache, mild facial weakness, and forgetfulness. Vascular imaging studies revealed a right putaminal hemorrhage secondary to a 3-mm lenticulostriate artery dissecting aneurysm. Clinically, the patient did well, with marked improvement in presenting symptoms enabling his return to mountain climbing. Follow-up angiography showed spontaneous resolution of the arterial dissecting aneurysm. Among the 41 reported cases, 19 were idiopathic, 5 associated with hypertension, and 17 related to various conditions such as Moyamoya disease, arteriovenous malformation, systemic vasculitis, intraventricular tumor, or substance abuse. Of the 42 cases, including the present case, 28 were surgically or endovascularly managed and 12 observed. Only one of the reported cases, a 33-year-old man with Moyamoya disease, who was managed conservatively, died of rebleeding. CONCLUSION: There is no common consensus in the literature on a single treatment strategy for a lenticulostriate artery aneurysm. The present case illustrates that observation and follow-up vascular imaging can be an important treatment strategy, allowing healing of the vessel wall and disappearance of the dissecting aneurysm.

Middle meningeal artery arising from the basilar artery.

Various anomalies for the origin of the middle meningeal artery (MMA) have been described in the literature. However, origin of the MMA from the basilar trunk is an extremely rare variant. We report on a 54-year-old female who presented with frequent headaches; magnetic resonance imaging showed a right parietal meningioma. The abnormal origin of the middle meningeal artery from the basilar artery was diagnosed by angiography performed for preoperative embolization of the tumor. We report on the case with a review of the embryologic basis, possible explanations for this aberrant origin, and its clinical implications.

Distal anterior choroidal artery aneurysm following iatrogenic posterior cerebral artery occlusion : a case report and review of literature.

Aneurysms of the anterior choroidal artery are uncommon and account for only 2-5% of all intracranial aneurysms. Distal anterior choroidal artery aneurysms are rare and the pathogenesis of this aneurysm may be different from typical proximal ones. We describe an unusual case of ruptured de novo distal anterior choroidal artery aneurysm in a 55 year-old man who had previously undergone endovascular proximal occlusion for a fusiform aneurysm of the ipsilateral posterior cerebral artery (PCA). A comprehensive review of literature using Medline, PubMed and all related journals was also performed. Only 34 reported distal AchoA aneurysms were found: 16 associated with moyamoya disease, 10 idiopathic, two with atherosclerosis, two with arteriovenous malformation, two dissecting, one infectious and one due to trauma. It is probable that the increased hemodynamic stress within the AchoA contributed to the formation and rupture of the reported aneurysm. This late complication needs to be considered when large intracranial vessels are iatrogenically occluded in the management of complex intracranial aneurysms.