The formation mechanisms of rare intracranial aneurysms are various, which lead to various kinds of treatment methods. The present article summarized the pathogenesis, pathologic changes in vascular walls and imaging features of rare intracranial aneurysms including segmental ectasia, aneurysms with dissection, aneurysms with intramural hemorrhage, mycotic aneurysms, aneurysms related to HIV, neoplastic aneurysms and traumatic aneurysms through literature review.
Diagnostic Imaging ; Dilatation, Pathologic ; Humans ; Intracranial Aneurysm ; diagnosis ; pathology ; therapy

Studies have shown that chronic inflammatory response plays a key role in intracranial aneurysms (IA) formation and progression, and macrophages regulate the formation and progression of IA through a variety of pathways. Bone marrow monocyte-derived macrophages and resident-tissue macrophages infiltrate the vessel wall, after infiltration macrophages are polarized into various polarization phenotypes dominated by M1-like and M2-like cells. Polarized phenotypes of macrophages can regulate the formation and progression of intracranial aneurysms by releasing cytokines and regulating the inflammatory response of other immune cells, as well as release different cytokines to regulate the process of extracellular matrix remodeling. Some important progresses have been made in the clinical detection and treatment in targeting macrophages. This review provides a summary on the pathogenesis of IA and potential drug targets to prevent the formation and rupture of intracranial aneurysms.
Cytokines ; Disease Progression ; Humans ; Inflammation ; Intracranial Aneurysm ; complications ; drug therapy ; pathology ; Macrophages ; metabolism

PURPOSE: Pathogenesis and treatment of spontaneous dissecting aneurysm of the intracranial vertebral artery (VA) remain controversial. This study was designed to provide management strategies and to improve management outcome in patients with these aneurysms. MATERIALA AND METHODS: Among a total of 1,990 patients treated for intracranial aneurysms from February 1992 to June 2005, 28 patients (1.4%) were treated either by surgery (8 patients) or neurointervention (20 patients) for spontaneous dissecting aneurysms of the intracranial VA. Twenty-two patients had ruptured aneurysms. We analyzed indications of surgery or neurointervention for each case, and assessed the management outcome at a 6-month follow-up. RESULTS: For selection of therapeutic options, patients were initially evaluated as possible candidates for neurointervention using the following criteria: 1) poor clinical grade; 2) advanced age; 3) medical illness; 4) unruptured aneurysm; 5) equal or larger opposite VA; 6) anticipated surgical difficulty due to a deep location of the VA-posterior inferior cerebellar artery (PICA) junction. Surgery was considered for patients with: 1) high-risk aneurysms (large or irregular shaped); 2) smaller opposite VA; 3) failed neurointervention; or 4) dissection involving the PICA. Management outcomes were favorable in 25 patients (89.3%). Causes of unfavorable outcome in the remaining 3 patients were the initial insult in 2 patients, and medical complications in one patient. CONCLUSION: Ruptured aneurysms must be treated to prevent rebleeding. For unruptured aneurysms, follow-up angiography would be necessary to detect growth of the aneurysm. Treatment modality should be selected according to the clinical characteristics of each patient and close collaboration between neurosurgeons and neurointerventionists is essential.
Adult ; Aged ; Aneurysm, Dissecting/*pathology/surgery/therapy ; Aneurysm, Ruptured/pathology/surgery/therapy ; Female ; Follow-Up Studies ; Humans ; Intracranial Aneurysm/*pathology/surgery/therapy ; Male ; Middle Aged ; Retrospective Studies ; Treatment Outcome ; Vertebral Artery/*pathology/surgery

This report documents the treatment of a giant aneurysm of the internal carotid artery bifurcation with a fistula to the cavernous sinus, which appeared following closed head trauma. A 39-year-old man suffered from a blunt head trauma in an automobile accident. Two weeks after the trauma, progressive chemosis of left eye was presented. Four months after the trauma, digital subtraction angiography showed an internal carotid artery bifurcation aneurysm, with drainage into the cavernous sinus. The lesion was successfully obliterated with preservation of the parent artery by using coils in conjunction with Onyx. Follow-up angiography obtained 3 months postoperatively revealed persistent obliteration of the aneurysm and fistula as well as patency of the parent artery. Endovascular treatment involving the use of coils combined with Onyx appears to be a feasible and effective option for treatment of this hard-to-treat lesion.
Adult ; Carotid Artery Diseases ; diagnosis ; therapy ; Carotid Artery, Internal ; Cavernous Sinus ; pathology ; Drainage ; Humans ; Intracranial Aneurysm ; diagnosis ; etiology ; Male

OBJECTIVE: Intracranial stenting for stent-assisted coiling of aneurysms requires adequate follow-up imaging. The aim of this in vitro study was to compare in-stent artificial luminal narrowing on contrast-enhanced MR angiograms (CE-MRA) when applying Neuroform(R) and Enterprise(R) stents for stent-assisted coiling. MATERIALS AND METHODS: Two intracranial nitinol stents (Enterprise(R) and Neuroform(R)) were placed in silicon tubes and then imaged at 3 T and 1.5 T by the use of a T1-weighted three-dimensional spoiled gradient-echo sequence with minimal TR and TE. CE-MRAs were obtained by using different imaging planes, voxel sizes, and bandwidths, and with or without parallel imaging. Artificial lumen narrowing (ALN) was calculated and the results were compared. RESULTS: Lower magnetic field strength, axial plane perpendicular to axis of stent, and wider bandwidth resulted in a lower ALN on CE-MRA for both stents. Larger voxel size resulted in lower ALN for Neuroform(R) stent. The parallel imaging acceleration factor did not affect ALN. The mean ALN was lower for Neuroform(R), but it was not significant by a paired t test. CONCLUSION: CE-MRA of the stented lumen of vascular phantom was partially impaired with ALN. Consequently, image plane orientation, magnetic field strength, bandwidth, and voxel size should be adjusted appropriately to reduce ALN.
Alloys ; Cerebral Angiography ; Contrast Media/diagnostic use ; Humans ; Imaging, Three-Dimensional ; Intracranial Aneurysm/*pathology/*therapy ; Linear Models ; Magnetic Resonance Angiography/*methods ; Phantoms, Imaging ; Reproducibility of Results ; *Stents

OBJECTIVE: Tiny cerebral aneurysms are difficult to embolize because the aneurysm's sac is too small for a single small coil, and coils within the aneurysm may escape from the confinement of a stent. This study was performed to introduce the stent-assisted coil-jailing technique and to investigate its effect on the coil embolization of tiny intracranial aneurysms. MATERIALS AND METHODS: Sixteen patients with tiny intracranial aneurysms treated with the stent-assisted coil-jailing technique between January 2011 and December 2013 were retrospectively reviewed and followed-up. RESULTS: All aneurysms were successfully treated with the coil-jailing technique, and at the end of embolization, complete occlusion of the aneurysm was achieved in 9 cases (56.3%), incomplete occlusion in 6 (37.5%), and partial occlusion in 1 (6.3%). Intraprocedural complications included acute thrombosis in one case (6.3%) and re-rupture in another (6.3%). Both complications were managed appropriately with no sequela. Follow-up was performed in all patients for 3-24 months (mean, 7.7 months) after embolization. Complete occlusion was sustained in the 9 aneurysms with initial complete occlusion, progressive thrombosis to complete occlusion occurred in the 6 aneurysms with initial near-complete occlusion, and one aneurysm resulted in progressive thrombosis to complete occlusion after initial partial occlusion. No migration of stents or coils occurred at follow-up as compared with their positions immediately after embolization. At follow-up, all patients had recovered with no sequela. CONCLUSION: The stent-assisted coil-jailing technique can be an efficient approach for tiny intracranial aneurysms, even though no definite conclusion regarding its safety can be drawn from the current data.
Adult ; Aged ; Cerebral Angiography ; Embolization, Therapeutic/*instrumentation ; Female ; Follow-Up Studies ; Humans ; Intracranial Aneurysm/pathology/*therapy ; Magnetic Resonance Angiography ; Male ; Middle Aged ; Retrospective Studies ; Severity of Illness Index ; Stents ; Treatment Outcome

OBJECTIVE: To evaluate the usefulness of time-resolved contrast enhanced magnetic resonance angiography (4D MRA) after stent-assisted coil embolization by comparing it with time of flight (TOF)-MRA. MATERIALS AND METHODS: TOF-MRA and 4D MRA were obtained by 3T MRI in 26 patients treated with stent-assisted coil embolization (Enterprise:Neuroform = 7:19). The qualities of the MRA were rated on a graded scale of 0 to 4. We classified completeness of endovascular treatment into three categories. The degree of quality of visualization of the stented artery was compared between TOF and 4D MRA by the Wilcoxon signed rank test. We used the Mann-Whitney U test for comparing the quality of the visualization of the stented artery according to the stent type in each MRA method. RESULTS: The quality in terms of the visualization of the stented arteries in 4D MRA was significantly superior to that in 3D TOF-MRA, regardless of type of the stent (p < 0.001). The quality of the arteries which were stented with Neuroform was superior to that of the arteries stented with Enterprise in 3D TOF (p < 0.001) and 4D MRA (p = 0.008), respectively. CONCLUSION: 4D MRA provides a higher quality view of the stented parent arteries when compared with TOF.
Adult ; Aged ; Cerebral Arteries/pathology ; *Contrast Media ; *Embolization, Therapeutic ; Female ; Humans ; *Imaging, Three-Dimensional ; Intracranial Aneurysm/*diagnosis/therapy ; *Magnetic Resonance Angiography/methods ; Male ; Middle Aged ; Sensitivity and Specificity ; *Stents ; Young Adult