Trend of cerebral aneurysms over the past two centuries: need for early screening.

OBJECTIVE: Cerebral aneurysms (CAs) are linked to variations in the cerebral basal arterial network (CBAN). This study aimed to find the optimal age for screening to detect brain arterial variations and predict aneurysms before rupture. DESIGN: An observational, quantitative and retrospective research. SETTING: The study analysed 1127 cases of CAs published from 1761 to 1938. Additionally, CT angiography images of 173-patients at the Royal Adelaide Hospital (RAH), South Australia between 2011 and 2019 were examined for the presence and the location of aneurysms in CBAN. PARTICIPANTS: The data were collected from patients at RAH and 407 published sources, including males and females across the entire age range, up to 100 years old. OUTCOME MEASURES AND RESULTS: Data, CAs cases, from 1761 to 1938 included (526 males, 573 females and 28 unknown sexes). The age of these patients varied from 18 months to 89 years (mean age=42, SD=18). Approximately 11.5% of the CAs occurred in patients aged <20 years. Among the 1078 aneurysms whose location was reported, 76% were located in the internal carotid (IC), middle cerebral (MC) and anterior communicating artery complex (AcomAC) regions, while the remaining 24% were in the vertebrobasilar region. Among 173 patients from RAH aged between 18 and 100 years (male=83 and female=90, mean age=60, SD=16), 94% of the CAs were found in the IC, MC and AcomAC regions. The pattern of aneurysm occurrence, as indicated by values at the 25th, 50th and 75th percentiles, along with the minimum and maximum patient ages, has remained consistent from 1761 to 2019. CONCLUSION: The distribution pattern of CAs in relation to sex, age and locations in the CBAN, remained steady over the last 260 years resulting in risk of strokes early in life. Therefore, early screening for CBAN segment variations is advised for stroke prevention if possible.

Relationship between cerebral aneurysms and variations in cerebral basal arterial network: a morphometric cross-sectional study in Computed Tomography Angiograms from a neurointerventional unit.

OBJECTIVE: Segments of cerebral basal arterial network (CBAN) dampen the peak pressure in blood flowing through these arteries, thus minimising the chances of development of cerebral aneurysms. The objective of this research was to find the relationship of occurrence of intracranial aneurysms to variations of the components of the CBAN. DESIGN AND SETTING: This is an observational, quantitative and retrospective research, which used cerebral CT angiography (CCTA) images. PARTICIPANTS: Cerebral CTA of 145 adult patients of both sexes were studied. MAIN OUTCOME MEASURES: Diameters of segments of CBAN were measured in CCTA images and the relative size of each vessel was calculated to standardise for differences in overall arterial sizes among patients. Relationships among sizes of CBAN components were analysed. Presence of aneurysms in different parts of the CBAN was recorded. RESULTS: Forty-six aneurysms in right internal carotid artery (ICA) and middle cerebral artery (MCA) and 32 aneurysms in left ICA and MCA segments were noted in 42 and 30 patients, respectively. Aneurysms in anterior communicating artery complex and vertebral-basilar arterial segments were seen in 27 and 8 patients, respectively, while they were not detected in parts of posterior cerebral artery (PCA). The significant (p<0.001) inverse relationships between sizes of posterior communicating artery and the first segment of PCA on both sides indicated that blood inputs to the second part of PCA were similar. Difference in means of the index of arterial size variation for people with aneurysms (mean 0.96, SD 0.23) and without aneurysms (mean 0.86, SD 0.22) was significant (p=0.015). CONCLUSION: Variation in segments of CBAN was quantified. The peak pressure dampening mechanism in such arterial segments reduces the chances of development of aneurysms.

Adding to the Allied Health Student Experience: Motivators, Deterrents, and How to Get More from Peer Teaching.

Volunteering as a peer tutor offers teaching experience to allied health students who will one day teach patients and colleagues. It also provides an opportunity for students to extend themselves personally and academically. Medical and nursing literature supports peer teaching, yet fewer publications describe the experience of allied health students. This study investigated the effects of cross-level peer tutoring in anatomy, for the peer tutors and their students. Peer tutors revealed their primary concern as lacking anatomical knowledge; however, students valued the currency of their student experience and the opportunity to discuss learning processes with a peer. Recommendations from peer tutors and students included: recognition of the value of interactions between students and peer tutors; value of teaching how to learn, rather than content; and for academics to introduce peer tutors as peers, which clarifies the students' expectations of the peer tutor.

Quantifying asymmetry of anterior cerebral arteries as a predictor of anterior communicating artery complex aneurysm.

OBJECTIVES: The aim of this study was to establish an anatomical index for early prediction of the risk of development of aneurysms in anterior communicating arterial complex (AcomAC). The asymmetric diameter of one anterior cerebral artery (ACA) to other could alter haemodynamics and may contribute to formation of aneurysms in AcomAC and be a reliable predictor of the risk of development of aneurysms. DESIGN AND SETTING: This is a retrospective, observational and quantitative study, which used cerebral computed tomography angiography (CCTA) scans in South Australia. PARTICIPANTS: CCTA scans of 166 adult patients of both sexes were studied. MAIN OUTCOME MEASURES: The internal diameters of the proximal segments of ACAs (A1s) were measured. Position and presence or absence of aneurysms in AcomAC were determined. The ratio of A1 diameters was taken as a measure of A1 asymmetry. RESULTS: The ratio of diameters of A1s correlated with the occurrence of AcomAC aneurysms. The risk of development of aneurysms in AcomAC was much greater (80%, OR=47.3) when one A1 segment's radius was at least 50% larger (ie, 2.25 times cross-sectional area) than the other. CONCLUSION: The general information on asymmetric A1 has been published previously. The present findings have significant contribution since the A1s asymmetry ratios have been categorised in ascending order and matched with the presence of AcomAC aneurysms. The asymmetry ratio of the A1 is a good predictor for the development of AcomAC aneurysms. Reconstruction of the asymmetric A1 could be done if the technology gets advanced.

Asymmetries of total arterial supply of cerebral hemispheres do not exist.

BACKGROUND: Total blood supply to an organ, or its part, is proportional to its function. The aim of this project was to investigate whether there is a lateralisation of total functions of cerebral hemispheres by determining differences in the arterial blood supply to left and right cerebral hemispheres. METHODS: Diameters of right and left anterior, middle and posterior cerebral arteries were measured at specific sites and cross-sectional areas calculated in 203 adult brains (51 donated and dissected brain specimens and 152 cerebral arterial Computed Tomography Angiography and Magnetic Resonance Angiography images). FINDINGS: The sample size was large enough to provide a power of detecting as significant differences of 4%, but neither of the average cross-sectional areas of right anterior, middle and posterior cerebral arteries were significantly different from those of the anterior, middle and posterior cerebral arteries of the left side. Furthermore, combined areas of the three right cerebral arteries were not significantly different from combined areas of the left three arteries. This clearly indicates that the blood supply into the right cerebral hemisphere is not different from that of the left cerebral hemisphere. Therefore, there is no total functional lateralisation between the two cerebral hemispheres. CONCLUSION: Brain lateralisation, frequently discussed in the literature, does not deferentially influence the total activity levels of cerebral hemispheres.

The cerebral basal arterial network: morphometry of inflow and outflow components.

The aim of this project was to study how the morphology of the incoming and outgoing arterial components of the cerebral basal arterial network influence the blood flow to the brain. The cerebral basal arterial network consists of the circulus arteriosus cerebri anteriorly and the basilar artery posteriorly. Diameters of inflow vessels (bilateral vertebral and internal carotid arteries), connecting vessels (anterior communicating, basilar and bilateral posterior communicating arteries) and outflow vessels (anterior, middle and posterior cerebral arteries) were measured and cross-sectional areas calculated in 51 cadaveric brain specimens. The individual and the average cross-sectional areas of inflow arteries (51.43 mm2 ) were significantly bigger than the major outflow arteries (37.76 mm2 ) but smaller than the combined cross-sectional areas of outflow (37.76 mm2 ) and connecting (25.33 mm2 ) arteries. The difference in the size of arterial cross-sectional area and the presence of the connecting arteries in the cerebral basal arterial network provides a mechanism for lowering peaks in pressure, and demonstrates a function of the cerebral basal arterial network.