Clipping of Anterior Circulation Aneurysms: Operative Instructions and Safety Rules for Young Cerebrovascular Surgeons.

INTRODUCTION: Due to the constant development of the technique, in the last 30 years, the endovascular treatment of the intracranial aneurysms (IAs) has gradually superseded the traditional surgery in the majority of centers. However, clipping still represents the best treatment for some anterior circulation IAs according to their angioarchitectural, topographical, and hemodynamic characteristics. Thus, the identification of residual indications for clipping and the maintenance of training programs in vascular neurosurgery appear nowadays more important than ever. MATERIALS AND METHODS: We reviewed our last 10-year institutional experience of ruptured and unruptured IAs clipping. We appraised in detail all technical refinements we adopted during this time span and analyzed the difficulties we met in teaching the aneurysm clipping technique to residents and fellows. Then, we described the algorithm of safety rules we used to teach young neurosurgeons how to surgical approach anterior circulation IAs and develop a procedural memory, which may intervene in all emergency situations. RESULTS: We identified seven pragmatic technical key points for clipping of the most frequent anterior circulation IAs and constructed a didactic approach to teach young cerebrovascular surgeons. In general, they concern craniotomy; cisternostomy; obtaining proximal control; cranial nerve, perforator, and vein preservation; necessity of specific corticectomy; aneurysm neck dissection; and clipping. CONCLUSION: In the setting of an IA clipping, particularly when ruptured, the young cerebrovascular surgeon needs to respect an algorithm of safety rules, which are essential not only to avoid major complications, but they may intervene during the difficulties helping to manage potentially life-tethering conditions.

Vestibular and visual brain areas in the medial cortex of the human brain.

Self-motion perception involves an interaction between vestibular and visual brain regions. In the lateral brain, it includes the parietoinsular vestibular cortex and the posterior insular cortex. In the medial cortex, the cingulate sulcus visual (CSv) area is known to process visual-vestibular cues. Here, we show that the vestibular-visual network of the medial cortex extends beyond area CSv. We examined brain activations of 36 healthy right-handed participants by functional magnetic resonance imaging (fMRI) during stimulation with caloric vestibular, thermal, or visual motion cues. Consistent with previous research, we found that area CSv responded to both vestibular and visual cues but not to thermal cues. Moreover, the V6 complex and the precuneus motion (PcM) area responded primarily to (laminar-translational) visual motion cues. However, we also observed a region inferior to CSv within the pericallosal sulcus (vicinity of anterior retrosplenial) that primarily responded to vestibular cues. This vestibular pericallosal sulcus (vPCS) region did not respond to either visual or thermal cues. It was also distinct from a more posterior motion-sensitive region in the retrosplenial complex (mRSC) that responded to (radial) visual motion but not to vestibular and thermal cues. Together, our results suggest that the vestibular-visual network in the medial cortex not only includes areas CSv, PcM, and the V6 complex but also two additional brain regions adjacent to the callosum. These two brain regions exhibit similarities in terms of their locations and responses to vestibular and visual cues with self-motion-related brain regions recently described in nonhuman primates.NEW & NOTEWORTHY Self-motion perception involves several vestibular and visual cortical regions. Within the medial cortex, the cingulate sulcus visual (CSv) area, the precuneus motion (PcM) area, and the V6 complex respond selectively to self-motion cues. Here, we show that vestibular information is also processed in the pericallosal sulcus (vPCS), whereas (radial) visual motion information is associated with activation in the retrosplenial cortex (mRSC).

Tela-choroidea-to-anterior-cerebral-artery distance (TACAD): novel marker on color Doppler to identify fetuses with complete or partial agenesis of corpus callosum.

OBJECTIVES: To assess objectively the course of the anterior cerebral artery (ACA) by measuring its distance to the tela choroidea in the midsagittal view, and to compare this distance in normal fetuses with that in those with agenesis of the corpus callosum (ACC), a condition known to be associated with an abnormal course of the ACA. METHODS: The tela-choroidea-to-anterior-cerebral-artery distance (TACAD) was measured in the midsagittal view of the brain on color Doppler, between the anterior border of the tela choroidea and the ACA at the level of the callosal genu. Reference ranges in relation to gestational age were established in a prospective, cross-sectional study of 253 normal healthy fetuses between 19 and 36 weeks of gestation. The study group included fetuses with complete ACC (n = 28) or partial ACC (n = 18). RESULTS: TACAD of normal fetuses showed an increase during the second half of pregnancy, with a mean value of 10.1 mm and 14.2 mm at 22 and 30 weeks of gestation, respectively. All (28/28) fetuses with complete ACC and 83% (15/18) of those with partial ACC had significantly shorter TACAD, with mean values of 3.9 mm and 6.6 mm, respectively. CONCLUSIONS: TACAD is a measurement that is simple to obtain during fetal color Doppler neurosonography, which enables quantification of the course of the ACA and pericallosal artery. TACAD is shorter in fetuses with complete or partial ACC than in normal fetuses and provides an objective, quantifiable value, rather than merely descriptive information. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Fusiform aneurysms of anterior cerebral artery: center experience and systematic literature review.

Fusiform aneurysms of the anterior cerebral artery (ACA) are uncommon, and the natural history of this entity is poorly characterized. Along with our center experience, we conducted a systematic literature review to help shed light on the clinical course of ACA fusiform aneurysms. We queried our institutional database to identify cases with fusiform aneurysms of ACA. In addition, following the PRISMA algorithm, we identified all reported cases published in the English literature from the inception of PubMed until December 2022. We categorized clinical presentations into three categories: (i) traumatic/iatrogenic, (ii) spontaneous symptomatic ruptured/unruptured, and (iii) spontaneous asymptomatic aneurysms. We utilized descriptive statistics. We identified seven cases from our center along with 235 patients from published literature. Blunt trauma was responsible for the development of 19 aneurysms. Sixty-three percent of these aneurysms tend to rupture within 2 weeks from the initial trauma, and despite treatment, only 74% of these patients had good clinical outcomes. Spontaneous symptomatic presentation occurred in 207 patients and was often associated with previous/concomitant ACA dissection. Subarachnoid hemorrhage from ruptured aneurysms was the most common presentation. Spontaneous symptomatic fusiform aneurysm is rapidly evolving lesions, and treatment is necessary. Three of our own cases were treated with an endovascular flow diverter (pipeline) stenting with good outcomes. Spontaneous asymptomatic aneurysms were reported in nine patients. These lesions are often associated with other vascular abnormalities. Treatment included surgical clipping with good clinical outcomes. Instead, four patients from our center database were managed conservatively with equally good outcomes. Our study demonstrates good clinical outcomes when fusiform aneurysms of ACA, especially when symptomatic, are treated promptly with either reconstructive or deconstructive therapies.

Assessment of pericallosal artery at 11-14 weeks of gestation: Cohort study and meta-analysis.

OBJECTIVES: To report the rate of visualization of the pericallosal artery (PCA) in the first trimester of pregnancy (11-14 weeks). METHODS: Prospective observational study of consecutive fetuses undergoing first trimester risk assessment for chromosomal anomalies. The presence of PCA was assessed in a midsagittal view of fetal brain using high-definition power Color Doppler. A normal course of the PCA was defined as the visualization of an artery emerging from the anterior cerebral artery running parallel the corpus callosum (CC). The reference standard was the visualization of CC and PCA between the 20 and 22 weeks of gestation. We also performed a systematic review and meta-analysis of the published literature. Multivariate logistic regression and random-effect meta-analyses of proportion were used to analyze the data. RESULTS: Cohort study: Five-hundred women were included. PCA was identified trans-abdominally or transvaginally at 11-14 weeks of gestation in 98.8% (95% CI 97.4-99.6: 494/500); of the four cases of PCA not identified one had a diagnosis of complete agenesis of the corpus callosum during the anomaly scan which was confirmed at birth. Systematic review of the published literature: Six studies (1093 fetuses, including the present series) were included. The PCA was detected at the 11-14 weeks scan and confirmed to co-exist with a normal CC at time of the anomaly scan in 96.9% (95% CI 93.8-99.0); 20.6% (95% CI 5.7-41.7) of fetuses with no clear identification of the PCA at the 11-14 weeks scan had a normal appearance of the CC at the time of anomaly scan. CONCLUSION: Prenatal ultrasonography has a high diagnostic accuracy in detecting PCA in the first trimester. Visualization of the PCA at the time of 11-14 scan is highly specific for the presence of a normal CC later in pregnancy.

Contralateral Transradial Access for Coil Embolization of Distal Anterior Cerebral Artery Aneurysm Associated With a Steep Ipsilateral A1-A2 Angle.

OBJECTIVE: Endovascular treatment of distal anterior cerebral artery aneurysms is commonly addressed via the ipsilateral A1 segment of the anterior cerebral artery. However, when the parent pericallosal artery has a sharp ipsilateral A1-A2 angle, catheterization through the ipsilateral A1 segment can potentially result in vessel injury, catheter kinking, and/or compromised/stagnant anterior cerebral artery flow. Here, we present a case of a distal anterior cerebral artery aneurysm associated with a steep ipsilateral A1-A2 angle treated with contralateral transradial coil embolization. CASE PRESENTATION: A 91-year-old woman presented with a ruptured left distal anterior cerebral artery aneurysm at the A3 segment. The parent pericallosal artery had a steep ipsilateral A1-A2 angle. To safely achieve coil embolization of the aneurysm, a contralateral transradial system via the right A1 segment was employed. Although a secondary ipsilateral transradial system was required for contrast injection, aneurysm obliteration was successfully achieved without vessel injury or system instability. CONCLUSION: The A1-A2 angle can be a key anatomical factor in the endovascular treatment of distal anterior cerebral artery aneurysms. The contralateral transradial system is a useful treatment option for distal anterior cerebral artery aneurysms associated with sharp ipsilateral A1-A2 angles. However, if the distal anterior cerebral artery aneurysm cannot be clearly visualized through the contralateral system, an ipsilateral system will be required for contrast injection.

Transradial quadraxial system for coil embolization of distal anterior cerebral artery aneurysms: A radial-first center case series and literature review.

PURPOSE: Endovascular treatment is technically challenging as distal anterior cerebral artery (DACA) aneurysms have distal location, small-caliber parent artery, and small size/wide neck. This study evaluated the feasibility and safety of the transradial approach (TRA) with a radial-specific neurointerventional guiding sheath as the first-line technique for DACA aneurysms. METHODS: We retrospectively analyzed an institutional database of consecutive patients with DACA aneurysm who underwent coil embolization using TRA. Ten consecutive patients were included in this study. After the radial-specific 6F Simmons guiding sheath (0.088″ inner diameter) was completely engaged into the target common carotid artery, a quadraxial system (6F Simmons guiding sheath/6F intermediate catheter/3.2F intermediate catheter/single microcatheter) was used for embolization. Then, we assessed for procedural success, angiographic outcomes, and procedure-related or vascular access site complications. RESULTS: Embolization procedures were conducted using simple coiling in eight and stent-assisted coiling with the trans-cell approach in two patients. The embolization procedure was successful in all patients (n = 10). Moreover, none presented with catheter kinking, parent artery flow stagnation, or system instability during the procedure. Immediate postprocedural angiography revealed complete obliteration in six and residual neck in four patients. Then, eight patients underwent follow-up angiography at a mean of 7.1 months, and none developed recanalization or required retreatment. The postprocedural course was uneventful, and there were no complications. CONCLUSION: The transradial quadraxial system had the ability to achieve sufficient stability and kink resistance in DACA aneurysm embolization. Thus, this method was feasible and safe and had a high success rate.

A distal anterior cerebral artery tripod branching to a bihemispheric pericallosal artery.

The anterior cerebral artery (ACA) branching pattern may be particularly complex and variant including bifurcations, trifurcations or quadrifurcations, thus leading to typical or atypical vessels. The bihemispheric ACA (BhACA) variant crosses the midline to supply the contralateral hemisphere. The current case highlights a left-sided ACA trifurcation into a bihemispheric pericallosal artery, and two ipsilateral atypical arteries: a callosomarginal artery of short course and a left-sided pericallosal artery of an aberrant course into the cingulate sulcus. The depicted trifurcation was characterized as a distal ACA tripod. The bihemispheric branch supplied the contralateral pericallosal area and coursed into the cingulate sulcus. Deviations from the typical ACA pattern, especially when they coexist are quite rare and may complicate neurosurgical approaches or raise diagnostic difficulties. The BhACA may be implicated in aneurysm formation and bilateral ischemia after its occlusion. Knowledge of such variants, as well as awareness of the complications they may be related to, is of great significance.

Cognitive and Behavioral Disorders in Patients with Precuneal Infarcts.

OBJECTIVE: Ischemic stroke of the precuneal cortex (PC) alone is extremely rare. This study aimed to evaluate the clinical, neurocognitive, and behavioral characteristics of isolated PC infarcts. METHODS: We assessed neuropsychological and behavioral findings in 12 patients with isolated PC infarct among 3,800 patients with ischemic stroke. To determine the most frequently affected brain locus in patients, we first overlapped the ischemic area of patients with specific cognitive disorders and patients without specific cognitive disorders. Second, we compared both overlap maps using the "subtraction plot" function of MRIcroGL. RESULTS: Patients showed various types of cognitive disorders. All patients experienced more than 1 category of cognitive disorder, except for 2 patients with only 1 cognitive disorder. Lesion topographical analysis showed that damage within the anterior precuneal region might lead to consciousness disorders (25%), self-processing impairment (42%), visuospatial disorders (58%), and lesions in the posterior precuneal region caused episodic and semantic memory impairment (33%). The whole precuneus is involved in at least one body awareness disorder. The cause of stroke was cardioembolism in 5 patients (42%), large artery disease in 3 (25%), and unknown in 4 (33%). CONCLUSIONS: This study showed a wide variety of neuropsychological and behavioral disorders in patients with precuneal infarct. Future studies are needed to achieve a proper definition of the function of the precuneus in relation to the extended cortical areas. PC region infarcts have been found to predict a source of embolism from the large arteries or heart.

Retractorless combined pterional and interhemispheric approach to achieve proximal control in pericallosal artery aneurysm: how I do it.

BACKGROUND: Pericallosal artery aneurysms differ from other cerebral aneurysms for the difficulty in establishing proximal vascular control during surgical clipping. A frontomedial craniotomy with combined pterional and interhemispheric approach allows obtaining a better proximal control. MATERIALS AND METHODS: We present our surgical technique to achieve a proximal vessel control in pericallosal artery aneurysm clipping using a combined pterional and interhemispheric approach through frontomedial craniotomy. This surgical technique is illustrated by an intraoperative video. CONCLUSION: Proximal control for pericallosal artery aneurysm clipping can be challenging. In selected cases, a single craniotomy allows performing two approaches and obtaining a safer proximal control for surgical clipping.

Traumatic Distal Anterior Cerebral Artery Aneurysms - Pathomechanism and Revascularisation Strategies.

Traumatic intracranial aneurysms (TICA) of the distal anterior cerebral artery (dACA) are exceptionally rare and display therapeutic challenges due to their angioanatomical characteristics. The objective of this work was to discuss the mechanisms of TICA formation of the dACA and to elucidate the best treatment and revascularization strategies in these patients based on two illustrative cases. Case 1: 20-year-old patient with a traumatic, partially thrombosed 14 × 10 mm aneurysm of the right pericallosal artery (rPericA), distal to the origin of the right callosomarginal artery (rCMA). Complete trapping of the right dissection A3 aneurysm and flow replacement extra-to-intracranial (EC-IC) bypass (STA - radial artery - A4) was performed. Case 2: 16-year-old patient with a traumatic polylobulated, partially thrombosed 16 × 10 mm aneurysm of the rPericA. Microsurgical excision of the A3- segment harboring the aneurysm and flow replacement intra-to-intracranial (IC-IC) bypass via reimplantation of the right remaining PericA on the contralateral PericA (end-to-side anastomosis) was performed (in situ bypass). TICA of the dACA are exceptionally rare. Mechanical vessel wall injury and aneurysm formation of the dACA in blunt head trauma is very likely due to the proximity of the dACA with the rigid free edge of the falx. Given their nature as dissecting (complex) aneurysm, trapping and revascularization is a very important strategy. The interhemispheric cistern offers multiple revascularization options with its numerous donor vessels. The IC-IC bypass is often the simplest revascularization construct.

Iatrogenic pericallosal artery aneurysm after endovascular procedure.

Iatrogenic brain aneurysms are rare and are usually a result of direct trauma to the arterial wall during various neurosurgical or endovascular procedures. Single cases of pericallosal posttraumatic and postsurgical aneurysms were previously reported. Herein, we report the first confirmed case of iatrogenic pericallosal artery aneurysm caused by an arterial wall injury during the endovascular treatment of another aneurysm. A 50-year-old woman with ruptured anterior communicating artery aneurysm was initially treated with balloon-assisted coiling. During the procedure the tip of a microwire inserted into balloon catheter placed in the pericallosal artery caused a local injury of the inner layer of the vessel wall and vasoconstriction, without bleeding, dissection, or flow disturbances visible in digital subtraction angiography (DSA). Control examination revealed dissecting pericallosal aneurysm. After standard dual-antiplatelet oral preparation, stent-assisted coiling of the pericallosal artery aneurysm was performed with residual contrast filling of the base of the aneurysm sac in control angiography (RROC III). After 6 months the control DSA examination showed entirely cured pericallosal aneurysm (RROC I) and reconstruction of the parent artery. Successful endovascular treatment of an iatrogenic pericallosal aneurysm was previously reported, and this method seems to be the first-choice treatment. In our case, endovascular stent-assisted coiling also allowed for safe exclusion from circulation of pericallosal dissecting aneurysm, and the implanted stent caused reconstruction of the parent artery, restoring the normal lumen diameter. The second endovascular treatment option considered was implantation of a flow-diverted stent into the pericallosal artery.

Endovascular treatment of distal anterior cerebral artery aneurysms: Long-term results.

BACKGROUND AND PURPOSE: Endovascular therapy is the first-line therapeutic option for intracranial aneurysms, however the results of the endovascular approach for distal anterior cerebral artery (DACA) aneurysms are not well-known. We assessed the immediate and long-term clinical and angiographic outcomes after endovascular coiling of DACA aneurysms. MATERIALS AND METHODS: We performed a retrospective analysis of all consecutive DACA aneurysms treated by endovascular coiling. Procedural complications, clinical, and angiographic results were prospectively recorded in an institutional aneurysm database between 1992 and 2013. RESULTS: Satisfactory initial occlusion was achieved for 85.9% of cases (79/92). There were three cases of intraprocedural rupture of the aneurysmal sac and three treatment failures, all involving small aneurysms (< 4 mm). Rates of procedure-related mortality and morbidity were respectively 1.1% and 0%. Scores of 5 (good recovery) or 4 (moderate disability) on the Glasgow Outcome Scale, indicating favorable outcome, were observed for 79.3% of patients (73/92) at hospital discharge. In follow-up, 13 cases of recanalization were observed, 12 of which were classified as major. Ten of the recanalizations underwent a complementary intervention. CONCLUSIONS: The endovascular management of DACA aneurysms appears to be efficacious and safe, although certain technical difficulties may emerge when aneurysms are small. A higher proportion of major recanalization events may imply a more frequent deployment of complementary interventions in comparison to aneurysms situated elsewhere.

Radiological classification of azygos anterior cerebral artery and evaluation of the accompanying vascular anomalies.

PURPOSE: There is not a classification of azygos anterior cerebral artery (ACA) based on anatomical branching levels in the literature. In the present study, a classification of azygos ACA was made based on radiological imaging for a common terminology, and frequency, accompanying vascular anomalies and malformations were investigated. METHODS: A total of 4913 cases who had brain CTA, MRA, contrast-enhanced MRI and DSA in January 2010-January 2020 period were screened for the study. Based on anatomical branching level, azygos ACAs were classified into four groups. Aneurysms, anomalies and malformations accompanying azygos ACA were identified. The associations of azygos ACA types with the presence of aneurysm or ACA A1 segment anomalies were investigated. RESULTS: Azygos ACA was observed in 57 cases (29 male and 28 female) and frequency of azygos ACA was 1.16%. Average age of the cases with ACA was 56.19 ± 19.65 years. Forty-eight of the cases had type C azygos ACA, four cases type B, four cases type D and one case type A azygos ACA. A total of nine intracranial aneurysms were identified in seven of the cases (12.28%). Five of the aneurysms were located in MCA and four in distal ACA. Most common vascular anomalies accompanying azygos ACA were unilateral vertebral artery hypoplasia and ACA A1 segment hypoplasia. Azygos types did not have significant correlations with the presence of aneurysms or ACA A1 segmental anomalies (p = 0.683 and p = 0.949, respectively). CONCLUSION: Azygos ACA is a rare variation, but it could be accompanied by aneurysms or other vascular anomalies.

[Giant thrombosed aneurysm of the pericallosal artery: clinical observation, literature review]. / Gigantskaia trombirovannaia anevrizma perikalleznoi arterii: klinicheskoe nabliudenie i obzor literatury.

Are characterized by Distal giant aneurysms of the anterior cerebral artery are an extremely rare pathology. There are less than 40 cases of this disease described in literature. OBJECTIVE: The aim of the article is to present the clinical observation of a successfully treated giant aneurysm of the pericallosal artery in a 58-year-old man, and also analyze the publications on distal cerebral aneurysms. MATERIAL AND METHODS: The data of a patient hospitalized with a suspected tumor of the left brain hemisphere spreading to the left lateral ventricle is presented. Repeated MRI suggests a giant subtotal thrombotic aneurysm of the left perical artery, which was confirmed by SCT angiography. The patient underwent aneurysm treping-cliping with dissection of the aneurysm sac. In the analysis of the literature it was shown that the frequency of perical artery aneurysms varies from 5.3-6.0%, and giant aneurysms of this localization are extremely rare and occur in 1-4.5% of all perical artery aneurysms. Unlike distal anterior cerebral artery aneurysms of small and medium size, giant aneurysms are characterized by pseudotumorrhagic symptoms, which causes diagnostic difficulties. CONCLUSION: It is necessary to remember about the diagnostic difficulties caused by the pseudotumorrhosis of the giant aneurysms of the pericallosal artery and the frequent negative angiography data due to total thrombosis of the aneurysmal sac. The gold standard is microsurgical clipping with excision of the aneurysmal sac. The prognosis for this group of patients is favorable.

Variability of T1-weighted signal intensity of pericallosal lipomas in the fetus.

BACKGROUND: Pericallosal lipomas are often associated with corpus callosum dysgenesis. The diagnosis of lipoma, suggested on ultrasonography, relies on the classic T1 hyperintensity on magnetic resonance imaging (MRI). However, this feature may be absent prenatally. OBJECTIVE: Our objective was to study the changes of T1 intensity in fetal lipomas with comparison to postnatal/postmortem data and to assess the factors influencing the signal variations of pericallosal lipomas on prenatal MRI. MATERIALS AND METHODS: Patients with callosum dysgenesis and interhemispheric hyperechogenicity suggestive of a pericallosal lipoma with available postnatal or postmortem data were included. Gestational age, lipoma size and pattern, corpus callosum size and changes in fetal fat T1 intensity were recorded. Comparison with postmortem neuropathology was available for one fetus. RESULTS: Eleven patients with callosum dysgenesis and pericallosal lipomas (seven curvilinear and four tubulonodular) were included. All MRI scans were performed in the third trimester. Curvilinear lipomas were thinner and six cases were associated with prenatal T1 iso-intensity. Typical T1 hyperintensity appeared on postnatal MRI only. All tubulonodular lipomas were much larger and showed prenatal T1 hyperintensity. In two patients, the lipoma increased in size on postnatal MRI. CONCLUSION: The type and size of a lipoma influence T1 prenatal intensity. Absence of T1 intensity was observed in curvilinear lipomas only. Curvilinear lipomas are much thinner. Changes in T1 intensity may also be related to fat maturation within the lipoma and, subsequently, to gestational age. In the case of callosum dysgenesis, absence of prenatal T1 pericallosal hyperintensity should not exclude the diagnosis of pericallosal lipoma.

Is the presence of corpus callosum predictable in the first trimester?

Corpus callosum agenesis (CCA) is a clinical condition accompanied by various aneuploidy and genetic syndromes. We identified the development of the corpus callosum (CC) in 278 patients before 18 weeks of gestational age by visualising the pericallosal artery (PCA) in the callosal sulcus and changes in the lengths and ratios of the midbrain (MB) and falx (F), which suggested elevation of the third ventricle and thalamus due to CCA in the first trimester. We succeeded in visualising the path of the PCA in 273 patients. As expected, we observed an increase in the lengths of the MB and F throughout the pregnancies. The MB:F ratio was 0.5-0.6, and it was independent of gestational age. In all 278 patients, the MB:F ratio was <0.6 (95th percentile = 0.79). We observed the presence of the CC during anatomical screening at gestational weeks 18-24. Visualisation of the PCA path (98% sensitivity) and calculation of the MB:F ratio <95th percentile (0.79-100% sensitivity) had very high sensitivity that indirectly confirmed the presence of the CC in the first trimester of pregnancy. Impact statement What is already known on this subject: After reading the articles for detecting the absence of corpus callosum (CC) at first trimester with midbrain (MB) and falx (F) measurement by Lachmann et al. ( 2013 ) and visualising pericallosal artery (PCA) as an indirect sign of CC agenesis by Pati et al. ( 2012 ), we aimed to have a look for our records visualising PCA in callosal sulcus and measure MB-F, as well as their ratios for an indirect sign of 'presence' of CC at first trimester. What the results of this study add: In recent literature, it is not possible to find many articles suggesting the presence of CC between 11 and 13 weeks of gestation. Díaz-Guerrero et al. ( 2013 ) and Pati et al. ( 2012 ) has researched visualising PCA path. Lachmann et al. ( 2013 ) reported an article for MB and F measurements in early suspicion of CC agenesis. Our study will be the first article in visualising PCA path and measuring MB-F lengths as well as their ratios for 'presence' of CC with high sensitivity rates (98% and 100%). What are the implications of these findings for clinical practice and/or further research: This study encourages clinicians visualising PCA path and measure MB-F lengths when they will try to visualise repetitive times and see how it is an easy procedure when you get used to it.

Diagnosis and treatment of pericallosal artery aneurysms.

OBJECTIVE: Pericallosal artery aneurysms are not common clinically. The microsurgery and endovascular therapy are surgically challenging operations. The objective of the study is to summarize their clinical symptoms and optimal treatment strategies of pericallosal artery aneurysms. METHODS: Nine cases of pericallosal artery aneurysms detected by digital subtraction angiography (DSA) were reviewed. The clinical manifestation, brain imaging characteristics, and optimal treatment methods were summarized. RESULTS: Patients with spontaneous aneurysm had good clinical outcomes after endovascular coiling or microsurgical clipping treatment. There were no any neurological function deficits in five patients. One patient suffered from permanent neurological function deficits. Patients with traumatic aneurysm pericallosal had relatively poor outcomes, including two patients showing disturbed consciousness and the paralysis of the lower limbs with slow recovery, and one patient was dead after the surgery. CONCLUSION: Spontaneous subarachnoid hemorrhage and interhemispheric fissure hematoma suggest spontaneously pericallosal aneurysm, while traumatic corpus callosum hematoma as well the accompanying embryo of intraventricular hemorrhage suggest traumatic pericallosal aneurysm. Endovascular embolization is the primary surgical treatment for pericallosal aneurysm, while patients with pericallosal aneurysm are not suitable for surgical treatment. Microsurgical clipping treatment may be a choice. However, both of these treatment strategies have high risk.

Median pericallosal artery with double proximal origin: case report and clinical consideration.

A 76-year-old male patient underwent magnetic resonance angiography of the head and neck vessels due to a recent incident of transitory ischemic attack. Cerebral angiogram uncovered the double proximal origin of the median unpaired pericallosal artery from the duplicated anterior communicating complex. The vessel curved around the corpus callosum and irrigated the paracentral lobule and the medial parietal cortical areas. The main trunks of the anterior cerebral arteries showed a branching pattern of the marginal callosal arteries, supplying orbital and frontal territories. The pre-communicating segment of the left anterior cerebral artery was identified as hypoplastic. The co-existence of the duplicated anterior communicating artery, with the medial pericallosal artery ascending from it, represents a potential danger for both open and endovascular surgery on the anterior circle of Willis as the deep half of this complex is obscured from the surgeon's eyes. Thorough interpretation of preoperative radiographic images and understanding of the developmental mechanisms of such variability are vital. The described branching arrangement of the anterior communicative region and possible mechanisms of migration with following fusion of the pericallosal arteries are discussed in this paper.

Endovascular treatment of distal anterior cerebral artery aneurysms using flow modulation devices: mid- and long-term results from a two-center study.

Purpose: Flow-diverter (FD) stents have become an established treatment for intracranial aneurysms in recent years, but their use for aneurysms in distal cerebral vessels with small carrier vessel diameters remains controversial. This study describes the method and mid- and long-term outcomes of FD treatment of distal anterior cerebral artery aneurysms (DACAAs) at two neurointerventional centers, to elucidate this topic and provide more in-depth data. Methods: Data for all patients at two neurointerventional centers who were treated with FDs for DACAAs in the pericallosal and supracallosal segment of the anterior cerebral artery were retrospectively analyzed. Data on periprocedural complications, and short-, mid- and long-term follow-up findings were recorded. Results: Forty-one patients were eligible for inclusion in the study. Three FD models were used, one of which had an anti-thrombotic coating. Two periprocedural complications (5%) occurred but did not cause a change in the mRS. In the long-term follow-up, at 29 months and beyond, 83% of assessable patients showed complete occlusion of the aneurysms without new neurological deficits. Conclusion: FDs are a safe and effective treatment approach for DACAAs. This study indicated a low risk of complications, and high closure rates in short-, mid- and long-term follow-up.