Automated Method for Intracranial Aneurysm Classification Using Deep Learning.

Intracranial aneurysm (IA) is now a common term closely associated with subarachnoid hemorrhage. IA is the bulging of a blood vessel caused by a weakening of its wall. This bulge can rupture and, in most cases, cause internal bleeding. In most cases, internal bleeding leads to death or other fatal consequences. Therefore, the development of an automated system for detecting IA is needed to help physicians make more accurate diagnoses. For this reason, we have focused on this problem. In this paper, we propose a 2D Convolutional Neural Network (CNN) based on a network commonly used for data classification in medicine. In addition to our proposed network, we also tested ResNet 50, ResNet 101 and ResNet 152 on a publicly available dataset. In this case, ResNet 152 achieved better results than our proposed network, but our network was significantly smaller and the classifications took significantly less time. Our proposed network achieved an overall accuracy of 98%. This result was achieved on a dataset consisting of 611 images. In addition to the mentioned networks, we also experimented with the VGG network, but it was not suitable for this type of data and achieved only 20%. We compare the results in this work with neural networks that have been verified by the scientific community, and we believe that the results obtained by us can help in the creation of an automated system for the detection of IA.

The anterior communicating artery variants: a meta-analysis with a proposed classification system.

Morphological and morphometric variants of the anterior communicating artery (AComA) have been described by multiple studies; however, a complete classification system of all possible morphological variants with their prevalence is lacking. The current systematic review with meta-analysis combines data from different databases, concerning the AComA morphological and morphometric variants (length and diameter). Emphasis was given to the related clinical implications to highlight the clinical value of their knowledge. The typical AComA morphology occurs with a pooled prevalence (PP) of 67.3%, while the PP of atypical AComA is 32.7%. The identified AComA morphological variants (artery's hypoplasia, absence, duplication, triplication, differed shape, fenestration, and the persistence of a median artery of the corpus callosum- MACC) were classified in order of frequency. The commonest presented variants were the AComA hypoplasia (8%) and the anterior cerebral artery (ACA) fusion (5.9%), and the rarest ones were the MACC persistence (2.3%), and the AComA triplication (0.7%). The knowledge of those variants is essential, especially for neurosurgeons operating in the area. Given the high prevalence of AComA aneurysms, an adequate and complete classification of those variants is of utmost importance.

Cerebral Arterial Bifurcations Harboring D Type Aneurysm are more Asymmetrical than those with C Type Aneurysm.

OBJECTIVES: This study was designed to determine aneurysm deviation and to compare anatomical differences of bifurcations harboring C and D-type aneurysms. MATERIALS AND METHODS: A total of 198 arterial bifurcations harboring aneurysms were enrolled in this study, including 58 anterior cerebral arteries (ACAs), 64 middle cerebral arteries (MCAs), 19 basilar arteries (BAs), and 57 internal carotid artery-posterior communicating arteries (ICA-PComAs). Aneurysms were defined as C type if the neck was located on the extension of the parent artery midline and D type if it was not, then, aneurysm deviation was examined. The angles forming between bilateral branching arteries and the main artery were lateral angles, and smaller one named φ2, larger one termed φ3, respectively, D2, S2, C2 and T2 representing the diameter, cross-sectional area, circumference, and tortuosity of the branch forming angle φ2 with the parent vessel, respectively, and D3, S3, C3 and T3 representing the corresponding values of the contralateral branch. The lateral angle ratio (LA ratio; larger lateral angle/smaller lateral angle), daughter artery ratio (DA ratio; the diameter of branch forming larger lateral angle with parent artery/ the diameter of contralateral branch), SA (S3/S2), CA (C3/C2) and TA (T3/T2) ratios were used to describe bifurcation symmetry. RESULTS: The angle φ2 of the main cerebral bifurcations was significantly smaller than the angle φ3, whereas T2 was significantly larger than T3. Most of the C-type and 100% of the D-type aneurysms deviated toward the angle φ2. The LA, DA, SA and CA ratios of ACA, MCA bifurcations and ICA-PComAs harboring D-type aneurysms were all significantly larger than those harboring C-type aneurysms; moreover, the LA, DA and SA ratios demonstrated significant differences between the bifurcations with C and D-type aneurysms, as determined by ROC analysis. CONCLUSIONS: The majority of C-type and all of the D-type aneurysms deviated toward the smaller lateral angle, and bifurcations harboring D-type aneurysms were more asymmetrical than those harboring C-type aneurysms.

Long-term predictive factors of the morphology based outcome in bare platinum coiled intracranial aneurysms: Evaluation by pre- and post-contrast 3D time-of-flight MR angiography.

PURPOSE: Our aim was to identify long-term predictive factors of the morphology-based outcome (MBO) of bare platinum coiled intracranial aneurysms. MATERIALS AND METHODS: A retrospective analysis of 96 bare platinum coiled intracranial aneurysms followed up from 1997 to 2016 using pre- and post-contrast 3D time-of-flight MR angiography (MRA) was performed. Logistic regression analysis was used to identify factors associated with a positive history of surrounding coil mass enhancement (SCME) and poor MBO. Spearman's rank correlation test was used to analyze the relationship between the initial angiographic result (IAR) class, sequential change of the SCME category, and MBO grade. RESULTS: Factors independently associated with poor MBO were incomplete IAR (OR=14.94, 95%CI: 2.46, 289.21, P=0.002) and a history of SCME (OR=4.13, 95% CI: 1.05, 18.65, P=0.043). The MBO grade strongly correlated with the IAR class (correlation coefficient [r]=0.84, P<0.0001). MBO grade correlated with sequential change of the SCME category (r=0.56, P<0.0001). The sequential change of the SCME category correlated with IAR class (r=0.53, P<0.0001). CONCLUSION: Although IAR and its class were strong long-term predictive factors of MBO, a history of SCME and upgrading of sequential change of SCME category were also long-term predictive factors of the MBO of bare platinum coiled intracranial aneurysms.

[On the classification of large and giant paraclinoid internal carotid artery aneurysms]. / K voprosu o klassifikatsii bol'shikh i gigantskikh paraklinoidnykh anevrizm vnutrennikh sonnykh arterii.

Large and giant intradural ICA aneurysms or the so-called paraclinoid aneurysms are a surgical challenge requiring high qualification of the neurosurgeon. Despite numerous publications on this topic, there is still no generally accepted classification of paraclinoid aneurysms. In this paper, we analyzed the definitions and classifications of paraclinoid aneurysms, which were available in the medical literature. The paper presents our own surgical classification of paraclinoid ICA aneurysms, which has been developed by Prof. Sh.Sh. Eliava and co-authors at the Burdenko Neurosurgical Institute. The classification is based on the aneurysm neck position relative to the ICA wall, aneurysm dome direction, and type of aneurysm clipping.

Associated Aneurysms in Infratentorial Arteriovenous Malformations: Role of Aneurysm Size and Comparison with Supratentorial Lesions.

BACKGROUND: The natural history and treatment of brain arteriovenous malformations (AVMs) is the object of ongoing debates and discussions. To capture the entirety of these complex lesions, associated vascular pathologies, such as associated aneurysms (AAs), have to be implemented in future risk stratification models, as they are believed to represent additional risk factors for intracranial hemorrhage. The present study aims to determine AA characteristics in posterior fossa AVMs and to compare with AAs accompanying supratentorial AVMs, with special focus on aneurysm size. METHODS: Patients with cerebral AVMs, treated in our department between 1990 and 2013, were analyzed retrospectively. Only patients with flow-related AAs of the feeding arteries were evaluated. Thus, patients harboring intranidal, venous or remote aneurysms were excluded. RESULTS: Of 485 patients with cerebral AVM, 76 patients harbored an AVM of the posterior fossa. Among those, 22 individuals exhibited a total of 35 AAs (n = 8 patients with multiple AAs). Most common location of AAs was the posterior inferior cerebellar artery (n = 20, 57%) and mean AA diameter was 7.9 mm (SD 5.5). In the subgroup of patients with a single AA, mean aneurysm size in posterior fossa AVMs was with 7.8 mm (SD 6.0; range 2-25 mm) significantly larger than the mean size of AAs with supratentorial AVMs (4.8 mm, SD 3.0; range 2-20 mm; p = 0.048). Intracranial hemorrhage was found in 18 of 22 patients (82%) with infratentorial AVMs, and of these, 11 patients suffered from aneurysm rupture. In 14 patients bearing a single AA, 8 (57%) had sustained hemorrhage from aneurysm rupture. The mean diameter of AAs was as supposed in the ruptured group with 9.8 mm (SD 6.9; range 4-25 mm) significantly larger than in the unruptured AA group exhibiting a mean of 5.0 mm (SD 3.3; range 2-10 mm; p = 0.038). Patients with posterior fossa AVMs and AAs were significantly older as compared to those patients with supratentorial lesions (57.1, SD 12.6 vs. 45.8 years, SD 15.9 years; p = 0.004), which was also evident in the subgroup of patients with single AAs (55.2, SD 11.7 vs. 45.8 years, SD 14.9 years; p = 0.038). CONCLUSIONS: AAs of posterior fossa AVMs are larger in diameter than aneurysms accompanying supratentorial AVMs. AA size influences risk for hemorrhage, which, together with the high number of hemorrhagic events in posterior fossa AVMs, justifies treating these pathologies. The higher age of patients with AVMs of the posterior fossa might be one reason for larger AAs in this cohort, when compared to patients with supratentorial AVMs and AAs.

Natural history and management of basilar trunk artery aneurysms.

BACKGROUND AND PURPOSE: Basilar trunk aneurysms (BTAs), defined as aneurysms distal to the basilar origin and proximal to the origin of the superior cerebellar artery, are rare and challenging to manage. We describe the natural history and management in a consecutive series of BTAs. METHODS: Between 2000 and 2013, 2522 patients with 3238 aneurysms were referred to our institution for aneurysm management. A retrospective review of this database was conducted to identify all patients with BTAs. RESULTS: In total, 52 patients had a BTA. Mean age was 56 (SD±18) years. Median clinical follow-up was 33 (interquartile range, 8-86) months, and imaging follow-up was 26 (interquartile range, 2-80.5) months. BTAs were classified into 4 causal subtypes: acute dissecting aneurysms, segmental fusiform ectasia, mural bleeding ectasia, and saccular aneurysms. Multiple aneurysms were more frequently noticed among the 13 saccular aneurysms when compared with overall population (P=0.021). There was preponderance of segmental ectasia or mural bleeding ectasia (P=0.045) in patients presenting with transit ischemic attack/stroke or mass effect. Six patients with segmental and 4 with mural bleeding ectasia demonstrated increasing size of their aneurysm, with 2 having subarachnoid hemorrhage caused by aneurysm rupture. None of the fusiform aneurysms that remained stable bled. CONCLUSIONS: BTAs natural histories may differ depending on subtype of aneurysm. Saccular aneurysms likely represent an underlying predisposition to aneurysm development because more than half of these cases were associated with multiple intracranial aneurysms. Intervention should be considered in segmental ectasia and chronic dissecting aneurysms, which demonstrate increase in size over time as there is an increased risk of subarachnoid hemorrhage.

An integrated, ontology-driven approach to constructing observational databases for research.

The electronic health record (EHR) contains a diverse set of clinical observations that are captured as part of routine care, but the incomplete, inconsistent, and sometimes incorrect nature of clinical data poses significant impediments for its secondary use in retrospective studies or comparative effectiveness research. In this work, we describe an ontology-driven approach for extracting and analyzing data from the patient record in a longitudinal and continuous manner. We demonstrate how the ontology helps enforce consistent data representation, integrates phenotypes generated through analyses of available clinical data sources, and facilitates subsequent studies to identify clinical predictors for an outcome of interest. Development and evaluation of our approach are described in the context of studying factors that influence intracranial aneurysm (ICA) growth and rupture. We report our experiences in capturing information on 78 individuals with a total of 120 aneurysms. Two example applications related to assessing the relationship between aneurysm size, growth, gene expression modules, and rupture are described. Our work highlights the challenges with respect to data quality, workflow, and analysis of data and its implications toward a learning health system paradigm.

Clinical characteristics and preferential location of intracranial mirror aneurysms: a comparison with non-mirror multiple and single aneurysms.

INTRODUCTION: The purpose of our study was to compare the clinical characteristics and preferential localization of aneurysms in three patient groups: single aneurysm, non-mirror multiple aneurysms, and mirror aneurysms. METHODS: We retrospectively reviewed the clinical and radiological data of 2223 consecutive patients harboring 3068 aneurysms registered at the Toronto Western Hospital between May 1994 and November 2010. The patients were divided into single, non-mirror multiple, or mirror aneurysm groups. Expected incidences of mirror aneurysms at each location were calculated on the basis of the single aneurysm incidences at each location. RESULTS: Patients with mirror aneurysms (n = 197) did not differ from patients with non-mirror multiple aneurysms (n = 392) in having female predominance (81.7 vs. 76.3 %) or a family history of intracranial aneurysm (20.5 vs. 17.6 %). When compared with expected incidences at each location, mirror aneurysms were more frequently found at the cavernous internal carotid artery (30 vs. 11.5 %) (p < 0.0001). Mirror aneurysms involving the posterior circulation were less frequent (6.7 %) than aneurysms in the single (19.6 %) or non-mirror multiple aneurysm groups (18.9 %) (p < 0.05). CONCLUSION: Patients with mirror aneurysms had similar clinical characteristics to non-mirror multiple aneurysm patients. Mirror aneurysms showed a predilection for the cavernous carotid artery, whereas they were comparatively rare in the posterior circulation.

Increased Expression of NLRP3 Inflammasome in Wall of Ruptured and Unruptured Human Cerebral Aneurysms: Preliminary Results.

BACKGROUND: A growing body of evidence suggests that inflammation actively participates in cerebral aneurysm initiation, progression, and rupture. The primary objective of this study was to assess the expression of NLR family, Pyrin-domain containing 3 (NLRP3) inflammasome in human cerebral aneurysms. METHODS: Aneurysmal domes (19 ruptured and 17 unruptured) from patients undergoing surgical treatment for ruptured or unruptured cerebral aneurysms were analyzed. A control sample comprising 4 middle cerebral arteries was obtained from autopsy subjects. The expression of NLRP3, apoptotic speck-containing protein with a card (ASC), caspase-1, and interleukin (IL)-1ß were assessed by immunohistochemistry. Immunofluorescence double staining was used to determine NLRP3, ASC, and caspase-1 cellular distribution. RESULTS: Expression of NLRP3, ASC, and caspase-1 were more abundant in ruptured aneurysm tissue than that in unruptured aneurysms, based on a semi-quantitative grading (P < .05). IL-1ß was also overexpressed in the ruptured cerebral aneurysms and associated with increased expression of NLRP3, ASC, and caspase-1 (P < .05). Furthermore, NLRP3, ASC, and caspase-1 immunoreactivity were colocalized with immunoreactivity of CD3 in T lymphocytes and CD68 in macrophages. CONCLUSIONS: NLRP3 inflammasome was expressed in the wall of human cerebral aneurysms and was more abundant in ruptured aneurysms than in unruptured. This study raises the possibility that NLRP3 inflammasome may be involved in the pathogenesis of human intracranial aneurysms, and this requires further study.

Comparison of clinical and radiologic outcomes among stent-assisted, double-catheter, and balloon-assisted coil embolization of wide neck aneurysms.

BACKGROUND: Endovascular treatment of intracranial aneurysms can be technically challenging in cases of wide necks or unfavorable dome-to-neck ratio. Coils deployed without supporting devices may herniate from the aneurysm sac into the parent artery, causing thromboembolic complications or vessel occlusion. Therefore, alternative strategies for managing wide-necked aneurysms have been introduced such as stent-assisted coil embolization (SAC), balloon-assisted coil embolization (BAC), and double-catheter coil embolization (DCC). METHODS: SAC, BAC, or DCC were used to treat 201 patients with 207 wide-neck aneurysms between 2008 and 2013. Initial occlusion rates, recanalization rates, and periprocedural complications were retrospectively evaluated. The mean follow-up periods for SAC, BAC, and DCC were 16.2 months, 11.6 months, and 14.3 months, respectively. RESULTS: Clinical and anatomical analyses were conducted in 201 patients with 207 anuerysms. Complete occlusion rates of SAC, DCC, and BAC were 63.8 %, 46.7 %, and 63.2 %, respectively, and incomplete occlusion rates were 13.4 %, 15.5 %, 10.5 %, respectively (p value = 0.798). No rebleeding or hemorrhage occurred after coil embolization. Recanalization rates did not differ among the SAC, DCC, and BAC groups (7.1 % vs. 11.1 % vs. 7.9 %, p value = 0.696). Statistically insignificant results were observed in the rate of periprocedural complications among SAC, DCC, and BAC (11.0 % vs. 13.3 % vs. 15.8 %, p value = 0.578). CONCLUSIONS: There were no significant differences in the recurrence rate and periprocedural complication rate, and no rebleeding or aneurysmal rupture after treatment. Sufficient occlusion rates were achieved with SAC, DCC, and BAC. Notably, DCC does not require the use of antiplatelet agents and achieves coil stability without compromising the parent artery or major branch. Thus, we believe that the double-catheter technique was found to be a feasible and safe treatment modality for branching wide-neck aneurysms.

Clipping versus coiling for intracranial aneurysms.

BACKGROUND AND PURPOSE: The aim of this study was to compare results of clipping and coiling for aneurysms of the anterior circle of Willis. Previous studies have not identified a clear superiority of one method over the other. MATERIAL AND METHODS: The study group included 165 consecutive patients. The assessment took into account the risk of death, neurological status according to the scale of the GOS and mRS, the incidence of early complications and quality of life measured by own surveys and questionnaire EORTC QLQ-C30 v. 3.0. RESULTS: Mean follow-up was more than four years. Early and late results of treatment after embolization and clipping for all patients did not differ. Evaluation of patients with bleeding aneurysms demonstrated better outcomes after embolization, however statistical significance was observed only in terms of symptomatic scale score of QLQ-C30 questionnaire (p=0.02). For patients with non-bleeding aneurysms better outcomes were obtained after clipping, but statistical significance was found only in the early results: more excellent results in GOS score at discharge (p<0.03) and fewer complications during hospitalization (p=0.02). CONCLUSIONS: Results of treatment after clipping and coiling do not differ in total for all patients, but differ depending on the presence of bleeding. Patients with bleeding aneurysms achieve better outcomes after coiling, and patients with non-bleeding aneurysms achieve better outcomes after clipping.

Anterior Communicating Artery Aneurysms: Surgical Strategy and Outcome based on Proposed Newer Classification.

BACKGROUND: The ruptured anterior communicating artery aneurysm is the most frequent intra-cranial aneurysm treated at any neurosurgical department. These aneurysms arise from either the A1-A2-Acom artery junction or Acom artery. The surgical outcome depends on the age of the patient, time duration between ictus and surgery, and Hunt and Hess grade at admission. In this article, we intend to analyze the surgical outcome based on our proposed classification with our overall experience of Acom aneurysm. METHODS: A retrospective review of our surgical database with 250 patients of ruptured Acom was done, and the location, morphology, and direction of aneurysm, along with other clinical parameters including the demographic profile, radiological findings, and intra-operative details, were studied. We classified the Acom based on both site of origin and morphology (Type I, junctional on the dominant side; Type II, fusiform with an ill-defined neck and branching pattern; Type III, saccular true Acom A) and secondarily as described in the literature on the basis of the direction of fundus (Type A-E). The clinical parameters were compared among the above groups using Fischer-exact and one-way analysis of variance test. RESULTS: A total of 250 patients (M: F =113:137) were included (mean age 52.1 ± 11.5 standard deviation years). 55.2% patients had left A1 dominance. Type I Acom A was commonly found on the left dominant circulation (P = 0.00). The difference in aspect ratio of Type I (2.0 ± 0.8) and Type II (1.8 ± 0.52) aneurysms was insignificant (P = 0.28). However, a significant difference in post-operative vasospasm among different types of aneurysms was found (P < 0.05). The Type I Acom A were anteriorly directed, while Type II and III were posteriorly directed (P = 0.001). The mean follow-up of the study was 44.4 ± 25.7 months, with age (P = 0.007) and Hunt and Hess grade (P = 0.001) at admission correlating with surgical outcome. CONCLUSION: Classifying the Acom A pre-operatively based on site and morphology, location, and direction of fundus helps in surgical planning and prognosis. The junctional 'Type IA aneurysms' are most common and possess a high intra-operative rupture rate. The anteriorly directed aneurysms have a better prognosis, and visual complaints are usually associated with anterior-inferiorly directed aneurysms.

Risk of rupture of small anterior communicating artery aneurysms is similar to posterior circulation aneurysms.

BACKGROUND AND PURPOSE: According to the International Study of Unruptured Intracranial Aneurysms (ISUIA), anterior circulation (AC) aneurysms of <7 mm in diameter have a minimal risk of rupture. It is general experience, however, that anterior communicating artery (AcoA) aneurysms are frequent and mostly rupture at <7 mm. The aim of the study was to assess whether AcoA aneurysms behave differently from other AC aneurysms. METHODS: Information about 932 patients newly diagnosed with intracranial aneurysms between November 1, 2006, and March 31, 2012, including aneurysm status at diagnosis, its location, size, and risk factors, was collected during the multicenter @neurIST project. For each location or location and size subgroup, the odds ratio (OR) of aneurysms being ruptured at diagnosis was calculated. RESULTS: The OR for aneurysms to be discovered ruptured was significantly higher for AcoA (OR, 3.5 [95% confidence interval, 2.6-4.5]) and posterior circulation (OR, 2.6 [95% confidence interval, 2.1-3.3]) than for AC excluding AcoA (OR, 0.5 [95% confidence interval, 0.4-0.6]). Although a threshold of 7 mm has been suggested by ISUIA as a threshold for aggressive treatment, AcoA aneurysms <7 mm were more frequently found ruptured (OR, 2.0 [95% confidence interval, 1.3-3.0]) than AC aneurysms of 7 to 12 mm diameter as defined in ISUIA. CONCLUSIONS: We found that AC aneurysms are not a homogenous group. Aneurysms between 4 and 7 mm located in AcoA or distal anterior cerebral artery present similar rupture odds to posterior circulation aneurysms. Intervention should be recommended for this high-risk lesion group.

[Surgery for unruptured middle cerebral artery aneurysm].

Although a large number of patients with unruptured middle cerebral artery (MCA) aneurysms (AN) have been treated by surgical clipping in Japan, there has yet been no comprehensive study investigating the surgical risks based on a quantitative evaluation of the extensive existing body of patient records. This systematic review was conducted to determine morbidity of the procedure by performing a meta-analysis of the literature. The authors used a PubMed and J-stage search from 2000 to 2011 for studies containing the surgical clipping of the unruptured MCA AN. There were 21 articles, containing a total 1,323 cases of unruptured AN with morbidity specifically located in the MCA. 54 cases indicated significant neurological deficits for a morbidity rate of 4.1% (95% CI; 3.0-5.1). A limited number of studies disclosed an incremental increase in morbidity with the size of the aneurysm. Smaller MCA AN (7±3 mm) presented a lower morbidity of 1.48%, whereas giant MCA AN (>25 mm) corresponded with a higher morbidity of 27.8%. Factors consistently associated with high morbidity included incorporated MCA branches, plaque at the neck of the AN, an unclippable configuration, and M1 superior wall AN. Complex aneurysms required a wide array of intracranial bypass procedures, yielding morbidity of 23.4% (95% CI; 20.9-25.9). This is the first systematic review and quantitative meta-analysis of the surgical complications related to unruptured MCA AN.

[Bifurcational diverticulum ("aneurisms") of brain arterial junctions].

The results of clinico-morfological investigation of 220 arteries of the brain base from dead patients with aneurisms are in the article. The new facts and terms such as bifurcational hemodynamic aneurisms, segmental arterial ring of the brain and aneurysmal disease of the brain have been introduced. We have showed that aneurisms forms in the area of bifurcation, but not in linear segments of vessels. A junction of arteries in the bifurcation of vessels, formed by connective tissue, units muscle segments and takes place in development of aneurisms. The term of "aneurism" as a saccular evagination of all layers of arterial wall was prejudiced. A term as "diverticulum" could be use for denomination of evagination. Two types of aneurysmal disease of the brain clinical course have been separated out. The fist one is dysembryoplastic type with connective tissue deficiency and the second one--involutional hypertensive type at patients with long-term arterial hypertension.

Endovascular treatment of an intracranial aneurysm with a ruptured bleb.

OBJECTIVE: To study the features and approaches of endovascular treatment for intracranial aneurysms with a ruptured bleb. METHODS: This retrospective study was carried out from June 2007 to June 2009 in Jilin University, Jilin, China. Thirty patients with intracranial aneurysms with ruptured blebs were included. The aneurysms were diagnosed by digital subtraction angiography (DSA), and the endovascular treatment was planned according to the relationship between the aneurysm body and the ruptured bleb. The aneurysms were classified into 4 types (type I, II, III, IV) based on the size of the neck of the aneurysm connected with the parent artery, the size of the body of the aneurysm, and the size of the junction formed between the aneurysm and bleb. Endovascular treatment for each type of aneurysm was performed. RESULTS: Type IV aneurysms were the most difficult operation performed, easily resulting in rupture and bleeding during surgery, whereas embolization of a type III aneurysm was relatively simple. Type I and II aneurysms resulted in better prognosis. Statistical analysis showed that the outcome of the treatment of type I and II aneurysms was better than that in type III and IV aneurysms, the outcome of type I, II, and III was better than that in type IV. CONCLUSION: The outcome of the endovascular treatment of an intracranial aneurysm with a ruptured bleb was related to the aneurysm type. Treatment in a type-dependent manner is therefore recommended.

Cerebral aneurysm classification based on angioarchitecture.

Cerebral aneurysms are commonly named based on their relationship with adjacent vessels in either the anterior or posterior circulation. Although such an approach has long proved useful, this terminology does not take into account potential hemodynamic forces or aneurysm wall properties that are likely to be important for cerebral aneurysm formation, growth, rupture, and treatment. Dissecting, traumatic, false, infectious, and tumorous aneurysms were excluded from review. Only aneurysms in which preoperative imaging studies and operative findings were sufficient for classification were included. All 329 reviewed aneurysms could be divided into 2 groups: fusiform (n=16) and saccular (n=313). Fusiform aneurysms could be subdivided into 2 types: simple (no branch vessel; n=10) and complex (one or more side branches; n=6). Saccular aneurysms could be subdivided into 3 groups: those not associated with a branch vessel (n=31), those associated with a side-branch vessel (n=125), and those located at a bifurcation (n=157). Each of these categories of aneurysms could be classified further based on its association with a conducting, primary, secondary, tertiary, or side-branch vessel. Classification of cerebral aneurysms according to this scheme adequately described all reviewed aneurysms. Grouping aneurysms according to this approach focuses on similarities in angioarchitecture and potential rheologic properties that should prove useful for evaluation of aneurysm growth, rupture, and treatment.

Kissing Aneurysms: Radiological and Surgical Difficulties in 30 Operated Cases and a Proposed Classification.

OBJECTIVE: The first aim of this study is to bring up the radiological and surgical difficulties of kissing aneurysms and to present solutions. The second aim is to develop a classification that can help to predict the difficulties encountered during surgery. METHODS: The records of 817 patients who were operated on for aneurysm were reviewed retrospectively to identify kissing aneurysms. The radiological and clinical databases of these patients were evaluated in detail. RESULTS: Kissing aneurysms were detected in 30 patients (3.6%). Radiologically correct diagnosis rate of kissing aneurysms was 80% throughout the series. The most common locations were the anterior communicating artery (12 cases, 40%) and the middle cerebral artery (12 cases, 40.0%). The ruptured aneurysm could not be detected preoperatively in 24% of the patients. Intraoperative rupture occurred in 4 patients (13.3%). Accompanying vascular anomaly/variation was seen in 16 patients (53.3%). As detailed in the text, kissing aneurysms were divided into 3 types according to their position with each other on the parent artery from the surgeon's point of view during surgery: type I (proximal/distal), type II (superior/inferior), and type III (right/left). CONCLUSIONS: Despite advanced angiographic techniques, even today, kissing aneurysms can be misinterpreted as a single bilobular aneurysm. The ruptured aneurysm may not be detectable preoperatively. These complex aneurysms have a high intraoperative rupture risk. Accompanying vascular anomalies are more common than expected. Clip selection and sequencing are important. Proposed classification helps the surgeon to be aware of intraoperative difficulties that he/she may encounter in advance.