Absence of pontine perforators in vertebrobasilar dolichoectasia on ultra-high resolution cone-beam computed tomography

Parent artery occlusion for flow-related aneurysms at the proximal segment of the main feeding arteries of cerebellar arteriovenous malformations

BACKGROUND

Flow-related aneurysms (FRAs) associated with cerebellar arteriovenous malformations (AVMs) are complicated, and their management is difficult. We performed a retrospective study to explore the efficacy and outcome of parent artery occlusion (PAO) for FRAs at the proximal segment of the main feeding arteries of cerebellar AVMs.

MATERIALS AND METHODS

A retrospective study was performed for patients admitted for a cerebellar AVM between January 2015 and December 2019. Patients were included if (a) they presented with a ruptured or symptomatic FRA at the proximal segment of the main feeding arteries of the cerebellar AVM, (b) the cerebellar AVM did not bleed before admission, (c) the FRA was secured via PAO of the parent feeding artery, and (d) the cerebellar AVM was not intentionally managed or embolized through other feeding arteries during hospitalization.

RESULTS

Eight patients aged between 27 and 72 (48.6 ± 14.3) years were identified. Eight ruptured and symptomatic FRAs at the proximal segment of the main feeding arteries of the cerebellar AVMs underwent PAO with coils or Onyx while preserving the arteries distal to the aneurysms. All the patients achieved a favorable recovery after treatment in a follow-up ranged from 8 to 48 months. One patient experienced FRA recurrence and underwent a second PAO.

CONCLUSIONS

PAO for FRAs at the proximal segment of the main feeding arteries of cerebellar AVMs is a feasible option. This method is effective in preventing re-rupture of the FRAs and relieving the symptoms in the short term, allowing sufficient time for the patients to receive subsequent treatment.

Spontaneous intracranial vertebral artery dissections presenting with subarachnoid hemorrhage

BACKGROUND

Vertebral artery dissection (VAD) is an infrequent source of subarachnoid hemorrhage (SAH), with a high mortality rate, primarily due to the risk of rebleeding both before and after medical intervention. This paper provides a comprehensive analysis of the anatomy, pathophysiology, clinical presentation, treatment strategies, and outcomes of intracranial vertebral artery dissections that result in subarachnoid hemorrhage.

METHODS

Comprehensive five-year literature review (2018-2022) and a retrospective analysis of patient records from our institution between 2016 and 2022. We included studies with a minimum of 5 patients.

RESULTS

The study incorporated ten series from the literature and 22 cases from CHUM. Key anatomical factors increasing the risk of VAD include the vertebral artery's origin from the aortic arch, asymmetry of the vertebral artery, and its tortuosity. Patients may display specific collagen and genetic abnormalities. The occurrence of VAD appears to be more prevalent in men. Those with a ruptured intracranial VAD typically show prodromal symptoms and present with severe SAH. Rebleeding within the first 24 h is frequent. While standard imaging methods are usually adequate for VAD diagnosis, they may not provide detailed information about the perforator anatomy. Treatment approaches include both deconstructive and reconstructive methods.

CONCLUSION

Ruptured VAD is a critical, life-threatening condition. Many patients have a poor neurological status at presentation, and rebleeding prior to treatment is a significant concern. Deconstructive techniques are most effective in preventing rebleeding, whereas the efficacy of reconstructive techniques needs more investigation.

Cerebral perfusion simulation using realistically generated synthetic trees for healthy and stroke patients

BACKGROUND AND OBJECTIVE

Cerebral vascular diseases are among the most burdensome diseases faced by society. However, investigating the pathophysiology of diseases as well as developing future treatments still relies heavily on expensive in-vivo and in-vitro studies. The generation of realistic, patient-specific models of the cerebrovascular system capable of simulating hemodynamics and perfusion promises the ability to simulate diseased states, therefore accelerating development cycles using in silico studies and opening opportunities for the individual assessment of diseased states, treatment planning, and the prediction of outcomes. By providing a patient-specific, anatomically detailed and validated model of the human cerebral vascular system, we aim to provide the basis for future in silico investigations of the cerebral physiology and pathology.

METHODS

In this retrospective study, a processing pipeline for patient-specific quantification of cerebral perfusion was developed and applied to healthy individuals and a stroke patient. Major arteries are segmented from 3T MR angiography data. A synthetic tree generation algorithm titled tissue-growth based optimization (GBO)1 is used to extend vascular trees beyond the imaging resolution. To investigate the anatomical accuracy of the generated trees, morphological parameters are compared against those of 7 T MRI, 9.4 T MRI, and dissection data. Using the generated vessel model, hemodynamics and perfusion are simulated by solving one-dimensional blood flow equations combined with Darcy flow equations.

RESULTS

Morphological data of three healthy individuals (mean age 47 years ± 15.9 [SD], 2 female) was analyzed. Bifurcation and physiological characteristics of the synthetically generated vessels are comparable to those of dissection data. The inability of MRI based segmentation to resolve small branches and the small volume investigated cause a mismatch in the comparison to MRI data. Cerebral perfusion was estimated for healthy individuals and a stroke patient. The simulated perfusion is compared against Arterial-Spin-Labeling MRI perfusion data. Good qualitative agreement is found between simulated and measured cerebral blood flow (CBF)2. Ischemic regions are predicted well, however ischemia severity is overestimated.

CONCLUSIONS

GBO successfully generates detailed cerebral vascular models with realistic morphological parameters. Simulations based on the resulting networks predict perfusion territories and ischemic regions successfully.

Cerebrospinal Fluid Venous Fistula Imaging with Ultrahigh-Resolution Cone-Beam Computed Tomography

This case report describes a cerebrospinal fluid venous fistula imaged with ultrahigh-resolution cone-beam computed tomography.

Interposition Intracranial-Intracranial Bypass Based on Anterior Cerebral Artery A1 Donor Anastomosis: Technical Advances, Outcomes, and Literature Review

BACKGROUND

The bypass technique is important for treating complex intracranial aneurysms and is infrequently performed. Intracranial-intracranial (IC-IC) bypass has shown many advantages in recent years.

OBJECTIVE

To review the techniques and outcomes of bypass based on anterior cerebral artery (ACA) A1 donor anastomosis in patients with intracranial aneurysm.

METHODS

We retrospectively reviewed the clinical and imaging data, surgical strategy, and follow-up outcomes of 7 patients treated from 2019 to 2022. Neurological function was assessed by the modified Rankin Scale (mRS). A literature review was performed using PubMed.

RESULTS

All 7 patients (3 male patients and 4 female patients; mean age, 50.4 ± 15.5 years) underwent aneurysm trapping or clipping using interposition IC-IC bypass based on ACA-A1 donor anastomosis. There were 6 middle cerebral artery (MCA) aneurysms and 1 posterior cerebral aneurysm in the series. One IC-IC bypass failed and was changed to extracranial-intracranial bypass. Three patients with MCA M1 aneurysm showed perforator-related infarction after the operation. The modified Rankin Scale score was 0 in 4 patients, 2 in 2 patients, and 1 in 1 patient. The long-term graft patency rate was 100%.

CONCLUSION

Interposition IC-IC bypass based on ACA-A1 donor anastomosis provides an effective way to achieve blood flow reconstruction in the treatment of complex aneurysms. This technique provides better caliber and volume compatibility and diminishes neck incision. Perforator-related infarction was the main complication because of involvement of the MCA M1 aneurysm location. Proximal clipping is preferred to avoid perforator-related infarction.

The impact of high-resolution cone-beam CT findings on decision-making for the treatment of unruptured middle cerebral artery aneurysms

Even with the advent of endovascular treatment for intracranial aneurysms, microsurgical clipping continues to play a significant role in the treatment of middle cerebral artery (MCA) aneurysms. Securing perforators around unruptured intracranial aneurysms (UIAs) is essential for minimizing procedural risks in each treatment option. Therefore, we herein investigated whether the findings of high-resolution cone-beam computed tomography (HR-CBCT) have an impact on decision-making for the treatment of MCA UIAs. Patients with MCA UIAs between October 2017 and September 2021 were consecutively recruited for this study. All patients underwent HR-CBCT and 3D-DSA before treatment. The imaging quality of both modalities to visualize the microvasculature around aneurysms was evaluated. Specific findings on the microvasculature surrounding aneurysms on HR-CBCT were investigated to facilitate microsurgical clipping. Fifty-two MCA UIAs were treated, including 43 by microsurgical clipping and 9 by endovascular approaches. The overall imaging quality of HR-CBCT was superior to that of 3D-DSA. Regarding microsurgical insights, sensitivity and specificity for the visualization of small vessels around aneurysms were 79 and 100%, respectively, using HR-CBCT, and 57 and 93%, respectively, using 3D-DSA. The presence of a low-density band between adhesive vessels and aneurysm sacs was indicative of successful and safe microsurgical dissection between these structures. HR-CBCT enabled visualization of the intracranial microvasculature around MCA UIAs at the submillimeter level in vivo. In cases in which the tight adhesion of the microvasculature to the aneurysm sac is indicated by HR-CBCT, an endovascular approach may be considered in order to avoid the risks associated with securing perforators.

Principles, techniques and applications of high resolution cone beam CT angiography in the neuroangio suite

The aim of this review is to describe the acquisition and reformatting of state of the art high resolution cone beam CT (HR-CBCT) and demonstrate its role in multiple neurovascular conditions as a tool to improve the understanding of disease and guide therapeutic decisions. First, we will review the basic principle of CBCT acquisition, followed by the injection protocols and the reformatting paradigms. Next, multiple applications in different pathological conditions such as aneurysms, arteriovenous malformations, dural arteriovenous fistulas, and stroke will be described. HR-CBCT angiography, widely available, is uniquely useful in certain clinical scenarios to improve the understanding of disease and guide therapeutic decisions. It rapidly is becoming an essential tool for the contemporary neurointerventionalist.AChoAho.

Prospects and Dilemmas of Endovascular Treatment for Vertebrobasilar Dolichoectasia

Vertebrobasilar dolichoectasia (VBD) is characterized by significant expansion, elongation, and tortuosity of the basilar artery and vertebral artery. Certain highly selected cases of VBD can require intervention. Recent advances in endovascular treatment (EVT) have renewed hope for patients with VBD. However, which cases of VBD can benefit from EVT still needs to be determined. Currently, little is known regarding this matter. Therefore, we performed a review of the literature from a PubMed search and cataloged our experience regarding the classification and natural history of VBD and the prospects, prognosis and complications of EVT. The findings can be summarized as follows: for asymptomatic VBD, “wait and see” or medical management may be a reasonable strategy. EVT may only be effective in certain patients. For saccular aneurysms in VBD, especially ruptured aneurysms, EVT is reasonable. For fusiform aneurysms in VBD, EVT can carry high complication rates and should be recommended with caution. For stenting reconstruction in VBD, the effect is uncertain. For the future of EVT of VBD, randomized controlled trials and the development of neurointerventional products are worth pursuing, but EVT in VBD still has a long way to go.

Identification of Carotid Artery Microstructure and Plaque Rupture Using C-Arm Cone-Beam CT: A Case Report

C-arm cone-beam computed tomography (CBCT) offers a high imaging resolution with a wide range of contrast to visualize vessels, soft tissue, and bone. We report the usefulness of CBCT in observing neovascularization, microcalcification, and plaque rupture. A 56-year-old man presented with vertigo and complain of an unsteady gait for 5 months. Catheter angiography demonstrated right severe carotid stenosis with irregular filling defect, which on high-resolution MRI showed vessel wall enhancement. The CBCT showed high density structures and linear contrast enhancement from the vascular lumen to the plaque, related to microstructure and plaque rupture. Carotid endarterectomy was performed, and histopathology confirmed that the high-density areas represented neovascularization and microcalcification, with linear enhancement representing plaque rupture. This is the first report showing that microcalcifications and plaque rupture can be identified by CBCT. Thus, CBCT can be used as a promising supplement to current imaging modalities to evaluate plaque components more accurately.

[Diagnosis and treatment of non-saccular vertebrobasilar aneurysms]

OBJECTIVE

To systematize the data on diagnosis and treatment of non-saccular vertebrobasilar aneurysms.

MATERIAL AND METHODS

We have analyzed modern and fundamental studies in the PubMed database for the period 1969-2020. The following keywords were used: non-saccular aneurysm, dolichoectasia, vertebrobasilar pool. Fifty-nine studies including 1 meta-analysis, 9 case reports, 24 reviews and 25 original articles were selected.

RESULTS

Analysis of literature data indicates various unresolved problems associated with difficult diagnosis and choice of treatment that results high rates of disability and mortality.

CONCLUSION

Data on anatomical features of non-saccular aneurysms, such as presence or absence of perforating arteries within the affected arterial segment, analysis of electrophysiological changes following brainstem compression by aneurysm can serve as factors that will improve treatment outcomes in these patients.

Cone-beam CT angiography to assess the microvascular anatomy of intracranial arterial dissections

BACKGROUND

Intracranial artery dissection is a rare and generally under-recognized cause of ischaemic stroke or subarachnoid haemorrhage.

OBJECTIVES

The aim of this study was to analyse the efficacy of cone-beam computed tomography angiography (CBCT-A) to detect arterial ultrastructural alterations in intracranial artery dissection.

METHOD

This is an observational and retrospective case series.

RESULTS

Between January 2018 and November 2020, four patients were admitted with an acute ischaemic stroke due to intracranial dissection studied with CBCT-A. In all cases, the CBCT-A documented vascular ultrastructural alterations related with the intracranial dissection.

CONCLUSIONS

CBCT-A is an intraprocedural diagnostic technique that is useful for the diagnosis of intracranial dissections.