Body composition and rupture risk of intracranial aneurysms.

BACKGROUND: Rupture of an intracranial aneurysm resulting in a subarachnoid hemorrhage (SAH) is a life-threatening situation. Obesity is an increasing health challenge associated with numerous comorbidities. However, recent studies have shown a surprising decreased risk of SAH with increasing body mass index (BMI). The aim was to explore associations between other anthropometric variables and the rupture risk of an intracranial aneurysm, which to our knowledge is lacking in present literature. METHODS: Using a bioelectrical impedance analysis device, we performed body composition analyses on 31 patients admitted with aneurysmal SAH (aSAH) and 28 patients with planned intervention on their unruptured aneurysm. We also collected information on comorbidities and relevant risk factors. Logistic regression was used to explore associations between anthropometric variables and patients with ruptured versus unruptured aneurysms. RESULTS: Unadjusted estimates showed a significant inverse relationship between body fat percent and aneurysmal rupture (OR [95% CI]: 0.92 [0.86, 0.97], P = 0.009), and between body fat mass and aneurysmal rupture (OR [95% CI]: 0.95 [0.90, 0.99], P = 0.047). These risk relationships remained significant in age- and sex-adjusted analyses for body fat percent (OR [95% CI]: 0.93, [0.87, 0.97], P = 0.028), and body fat mass (OR [95% CI]: 0.95 [0.90, 0.99], P = 0.041). CONCLUSIONS: In recent studies showing a paradoxical relation between aSAH and obesity, BMI was the only parameter investigated. We further explored this "obesity paradox" and found lower body fat in aSAH patients compared to UIA. Future studies should investigate these relationships in larger samples. Clinical Trial Registration NCT04613427, November 3, 2020, retrospectively registered.

Possible association of trichorhinophalangeal syndrome I and intracranial subependymoma.

Trichorhinophalangeal syndromes (TRPSs) are rare hereditary syndromes with autosomal dominant inheritance. Patients exhibit abnormalities including bulbous pear-shaped nose, broad columella, and long and flat philtrum, fine, sparse, brittle, slow-growing scalp hair, skeletal abnormalities, and short stature. Three families; age at subependymoma surgery, pathogenic TRPS1(NM_014112.5) variant, and subependymoma number are described.

Dyslipidemia and rupture risk of intracranial aneurysms-a systematic review.

Dyslipidemia is a well-established risk factor for coronary artery disease. However, the effect on cerebral artery disease, and more specifically the rupture risk of intracranial aneurysms, is unclear and has not yet been reviewed. We therefore performed a systematic review to investigate associations between different types of dyslipidemia and incidence of aneurysmal subarachnoid hemorrhage (aSAH). We used the MEDLINE, Embase, and Web of Science databases to identify clinical trials that compared the rupture risk among SAH patients with or without dyslipidemia. The risk of bias in each included study was evaluated using the Critical Appraisal Skills Program (CASP). Of 149 unique citations from the initial literature search, five clinical trials with a case-control design met our eligibility criteria. These studies compared aSAH patients to patients with unruptured aneurysms and found an overall inverse relationship between hypercholesterolemia and rupture risk of intracranial aneurysms. The quality assessment classified all included studies as high risk of bias. The evidence indicates that hypercholesterolemia is associated with a reduced rupture risk of intracranial aneurysms. However, it is not clear whether this relation is due to the dyslipidemic condition itself or the use of antihyperlipidemic medication.

Impaired cerebrovascular reactivity may predict delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

INTRODUCTION: Delayed cerebral ischemia (DCI) is a major cause of disability and death after aneurysmal subarachnoid hemorrhage. The literature suggests that impaired cerebrovascular reactivity (CVR) may be a predictor for DCI; still no CVR based prediction model has been developed. Increased knowledge about possible predictors of DCI can improve patient management in high-risk patients and allow for shorter hospital stay in low-risk patients. METHOD: CVR was examined in 42 patients with aneurysmal subarachnoid hemorrhage and 37 patients treated for unruptured intracranial aneurysm, using acetazolamide test with transcranial Doppler monitoring of blood flow velocities. Patients were followed for development of DCI, separated into clinical deterioration and radiographic infarction. RESULTS: For all patients, regardless of aneurysm rupture status, CVR was on average 5.5 percentage points lower on the ipsilateral side of aneurysm treatment. Patients with clinical deterioration due to DCI had lower CVR than patients without DCI, and the difference was larger on the contralateral side (33.9% vs. 49.2%). Two prediction models were constructed for clinical deterioration due to DCI. The area under the receiver operating characteristic curve was 0.82 in the model using established predictors, and 0.86 in the model that also included CVR. CONCLUSION: Our findings support the hypothesis that impaired CVR may be an independent predictor of clinical deterioration due to DCI, and may assist in identifying patients at risk after aneurysmal subarachnoid hemorrhage. Ipsilateral CVR reduction occurs in all patients after aneurysm treatment, regardless of DCI development, thus highlighting the need to evaluate ipsi- and contralateral CVR separately.

Anxiety and Depression in Patients with Intracranial Arachnoid Cysts-A Prospective Study.

BACKGROUND: Arachnoid cysts yield cognitive deficits that are normalized after surgical cyst decompression. OBJECTIVE: The present study aimed to investigate whether arachnoid cysts also affect symptoms of anxiety and depression, and if surgical cyst decompression leads to reduction of these symptoms. METHODS: Twenty-two adult patients (13 men and 9 women) with symptomatic temporal or frontal cysts were included in this questionnaire (Hospital Anxiety and Depression Scale [HADS])-based prospective study. The mean time between answering the preoperative questionnaire and surgery was 37 days. The patients answered the same HADS questionnaire 3-6 months postoperatively. RESULTS: Preoperatively, both patients with frontal (N = 4) and patients with temporal (N = 18) cyst had higher mean HADS anxiety scores than those found in the general population. For patients with temporal cyst, there was a significant or near-significant difference in anxiety and depression scores and the combined scores between those with right-sided cysts and those with left-sided cysts. Postoperatively, the HADS scores normalized and were no longer different from those of the general population. The difference in scores between patients with right and left temporal cyst also disappeared. CONCLUSIONS: Patients with arachnoid cyst have higher levels of anxiety and depression than do the general population and these scores were normalized after decompressive cyst surgery. We further found a hemispheric asymmetry: patients with a right temporal cyst showed higher anxiety, depression, and combined scores than did patients with a left temporal cyst. Also, this disparity normalized after cyst decompression. Thus, arachnoid cysts seem to affect not only cognition but also the level of affective symptoms.

Surgical decompression of arachnoid cysts leads to improved quality of life: a prospective study-long-term follow-up.

BACKGROUND: In a previous study, we reported a short-term (6 months) postoperative improvement of health-related quality of life (Qol) in patients operated for an arachnoid cyst (AC). The aim was to investigate whether this initial improvement was permanent. METHODS: A long-term (5 ± 2 years) prospective study comparing Qol and complaints before and 5 ± 2 years after surgical fenestration for AC in 76 adult patients, using the Short Form 36 (SF-36) scores, Glasgow Benefit Inventory (GBI) questionnaires, and Visual Analogue Scales (VAS) for headache and dizziness, similarly to what they did at short-term follow-up. RESULTS: At short-term and long-term follow-ups, 73.4% and 82%, respectively, of the patients were better from their headache compared with preoperative scores. The corresponding improvement rates for dizziness were 61.7% (short-term) and 67.9 (long-term). Preoperatively, the mean headache VAS score was 45.6; at short-term follow-up, this was reduced to 25.7, and at long-term follow-up, this further reduced to 24.8. The preoperative mean VAS score for dizziness (35.2) was reduced to 12.2 (short-term) and 13.9 (long-term). The significant postoperative improvement of patient-reported Qol at short-term follow-up remained at long-term follow-up across seven out of eight SF-36 dimensions and three out of four GBI subscale scores. Similar to at short-term follow-up, the Qol improvement is correlated to improvement in headache and/or dizziness. CONCLUSIONS: The previously reported postoperative, short-term improvement in Qol and complaints appears stable, as the improvement remains at long-term follow-up. This suggests that the beneficial effects of surgical treatment are long-lasting.

Time Course of Cerebrovascular Reactivity in Patients Treated for Unruptured Intracranial Aneurysms: A One-Year Transcranial Doppler and Acetazolamide Follow-Up Study.

BACKGROUND: Cerebrovascular reactivity (CVR) is often impaired in the early phase after aneurysmal subarachnoid hemorrhage. There is, however, little knowledge about the time course of CVR in patients treated for unruptured intracranial aneurysms (UIA). METHODS: CVR, assessed by transcranial Doppler and acetazolamide test, was examined within the first postoperative week after treatment for UIA and reexamined one year later. RESULTS: Of 37 patients initially assessed, 34 were reexamined after one year. Bilaterally, baseline and acetazolamide-induced blood flow velocities were higher in the postoperative week compared with one year later (p < 0.001). CVR on the ipsilateral side of treatment was lower in the initial examination compared with follow-up (58.9% versus 66.1%, p = 0.04). There was no difference in CVR over time on the contralateral side (63.4% versus 65.0%, p = 0.65). When mean values of right and left sides were considered there was no difference in CVR between exams. Larger aneurysm size was associated with increased change in CVR (p = 0.04), and treatment with clipping was associated with 13.8%-point increased change in CVR compared with coiling (p = 0.03). CONCLUSION: Patients with UIA may have a temporary reduction in CVR on the ipsilateral side after aneurysm treatment. The change in CVR appears more pronounced for larger-sized aneurysms and in patients treated with clipping. We recommend that ipsilateral and contralateral CVR should be assessed separately, as mean values can conceal side-differences.

Rupture prediction of intracranial aneurysms: a nationwide matched case-control study of hemodynamics at the time of diagnosis.

The authors used computer simulation to investigate the hemodynamics in 36 unruptured aneurysms on the first day the lesions were discovered; 12 of them later ruptured. Knowledge about any differences in hemodynamics at this early stage improves predictions about which patients will get a subarachnoid hemorrhage-a dangerous bleeding in the brain-and helps decide which patients should be treated in advance to avoid the bleeding.

Cerebrovascular reactivity after treatment of unruptured intracranial aneurysms--A transcranial Doppler sonography and acetazolamide study.

BACKGROUND: Cerebrovascular reactivity (CVR) is defined as the change in cerebral blood flow, or blood velocity, in response to a vasoactive stimulus. There is a possible association between impaired CVR and vasospasm after aneurysmal subarachnoid hemorrhage. Most studies on CVR and vasospasm have used healthy subjects as reference. However, due to potential different vascular features, CVR in persons with intracranial aneurysms may differ from CVR in healthy subjects. Therefore, our aim was to examine CVR in patients with unruptured intracranial aneurysms (UIA). METHODS: CVR was examined in 37 patients in the first postoperative week after treatment for UIA, using acetazolamide (AZ) test with transcranial Doppler monitoring of blood flow velocities. RESULTS: Mean blood flow velocity in the middle cerebral arteries was 58.5 (SD 12.8) cm/s at baseline, and 94.3 (SD 19.5) cm/s after stimulation with AZ. Mean CVR was 62.6 (SD 16.8) %. There was no significant difference when comparing right and left sides, and treated and untreated sides. A simple regression analysis suggested that CVR increased with 0.7% points for each year a patient aged (p=0.004). However, the significance disappeared in a multiple analysis (increase of 0.6% points per year, p=0.055). Other possible influencing factors (gender, smoking, hypertension, body mass index, aneurysm location and treatment modality) were not significantly associated with CVR. CONCLUSIONS: CVR in patients with UIA is not different from normal values reported in healthy subjects, and does not indicate a systemically impaired vascular system in patients with UIA. We suggest that CVR in age and gender matched healthy controls can be used as reference for persons with intracranial aneurysms.

Surgical Decompression of Arachnoid Cysts Leads to Improved Quality of Life: A Prospective Study.

BACKGROUND: There is no previous prospective study on the outcome of surgical decompression of intracranial arachnoid cysts (AC). OBJECTIVE: To investigate if surgical fenestration for AC leads to change in patients' health-related quality of life. METHODS: Prospective study including 76 adult patients operated for AC. Patients responded to Short Form-36 and Glasgow Benefit Inventory quality of life questionnaires, and to visual analogue scales, assessing headache and dizziness pre- and postoperatively. Patient scores were compared with those of a large sample of healthy individuals. RESULTS: Preoperatively, 84.2% of the patients experienced headache and 70.1% dizziness. Mean pre- versus postoperative Visual Analogue Scale scores for headache and dizziness dropped from 45.6 to 25.7 and from 35.2 to 12.2, respectively. Preoperative Short Form-36 scores were significantly below age norms in all subscales, but improved after surgery into normal range in 7 out of 8 subscales for middle-aged and older patients. Younger patients' scores remained lower than age norm in 6 out of 8 subscales. A significant postoperative improvement was seen in 3 out of 4 Glasgow Benefit Inventory subscales. Improvement in headache and/or dizziness, but not preoperative cyst size or reduction in cyst volume, correlated with improvement in 6 out of 8 Short Form-36 subscales and 3 out of 4 Glasgow Benefit Inventory subscales. Only 1 patient experienced a severe complication causing permanent invalidity. CONCLUSION: Surgery for AC can be performed with a fairly low risk of complications and yields significant improvement in quality of life correlated to postoperative improvement in headache and dizziness. These findings may justify a more liberal approach to surgical treatment for AC.

Continuous Local Intra-Arterial Nimodipine for the Treatment of Cerebral Vasospasm.

Vasospasm (VSP) is one of the major causes for prolonged neurologic deficit in patients with aneurysmal subarachnoid hemorrhage. Few case series have reported about continuous local intra-arterial nimodipine administration (CLINA) in refractory VSP. We report our experience with CLINA in a patient with refractory cerebral VSP.

Carotid intima-media thickness--a potential predictor for rupture risk of intracranial aneurysms.

BACKGROUND: Individual assessment of rupture risk of cerebral aneurysms is challenging, and increased knowledge of predictors for aneurysm rupture is needed. Smoking and hypertension are shared risk factors for atherosclerotic disease and cerebral aneurysms, and patients with atherosclerosis have an increased prevalence of intracranial aneurysms. Carotid ultrasound with evaluation of intima-media thickness (IMT) is a non-invasive, safe, rapid, well-validated and reproducible technique for quantification of subclinical atherosclerosis and assessment of cardio- and cerebrovascular risk. Increased IMT is associated with elevated risk for ischemic stroke and myocardial infarction, but sparse data exist on carotid ultrasound findings in patients with intracranial aneurysms. AIMS: The purpose of this study was to investigate carotid IMT in patients with unruptured intracranial aneurysms (UIA) and aneurysmal subarachnoid hemorrhage (aSAH), and to assess if IMT might be associated with aneurysm rupture risk. METHODS: Patients treated for saccular aneurysms (UIA and aSAH) from February 2011 to August 2012 were included. Standardized high resolution B-mode ultrasound assessment of carotid arteries was done after aneurysm treatment, and traditional vascular risk factors were recorded. Healthy partners of young patients with ischemic stroke were used as controls. RESULTS: 69 patients treated for UIA (n=28) and aSAH (n=41) were compared with 80 controls. Mean IMT was higher in patients with aSAH (0·79 mm) than patients with UIA (0·65 mm) and controls (0·63 mm). Multiple multinomial regression analysis comparing aSAH, UIA and control groups demonstrated that IMT was the only variable predicative of aSAH compared to UIA. According to the multiple regression model, the probability of having aSAH compared to non-rupture increased by 62% for each 0·10 mm increment of mean IMT (RRR=1·62, P=0·017). Taking into account only patients harboring intracranial aneurysms, simple binary logistic regression was then applied to the UIA and aSAH groups. According to this model the risk of belonging to the aSAH group increased with higher mean IMT values (OR=1·40 per 0·10 mm increase of mean IMT, P=0·024). CONCLUSION: There is an association between IMT and intracranial aneurysm rupture status at the time of aneurysm treatment. Carotid IMT can be a potential predictor of aneurysm rupture. IMT may thus be a possible adjunct in the risk assessment of aneurysm rupture, and a helpful tool in patient risk stratification and counseling.

Maze learning in patients with intracranial arachnoid cysts.

BACKGROUND: The temporal lobe is of importance for visuospatial orientation. Intracranial arachnoid cysts have a predilection for the temporal fossa, and might therefore affect visuospatial orientation. The aim was to find out whether temporal cysts affect maze learning and if surgical cyst decompression improves maze performance. METHODS: Forty-five patients with a temporal arachnoid cyst and 17 control patients with cervical disc disease were tested in a labyrinth route in the hospital corridors the day before surgery and at least 3 months postoperatively. RESULTS: Thirty-five cyst patients (78 %) experienced postoperative improvement of their preoperative complaints. The cyst patients spent significantly longer time than the controls navigating through the maze in the preoperative test, 161 s and 127 s, respectively, but there was no difference in number of errors between the two groups. However, the cyst patients improved significantly in the postoperative test, both with regards to number of errors they made and time spent, contrary to the control patients, whose postoperative performance equalled that of the preoperative test. For the cyst patients, postoperative improvement in the labyrinth test correlated with the clinical outcome-but not the neuroradiological outcome-after the operation. CONCLUSIONS: Thus, temporal arachnoid cysts may affect visuospatial orientation and learning in a reversible manner.

Protein profiling reveals inter-individual protein homogeneity of arachnoid cyst fluid and high qualitative similarity to cerebrospinal fluid.

BACKGROUND: The mechanisms behind formation and filling of intracranial arachnoid cysts (AC) are poorly understood. The aim of this study was to evaluate AC fluid by proteomics to gain further knowledge about ACs. Two goals were set: 1) Comparison of AC fluid from individual patients to determine whether or not temporal AC is a homogenous condition; and 2) Evaluate the protein content of a pool of AC fluid from several patients and qualitatively compare this with published protein lists of cerebrospinal fluid (CSF) and plasma. METHODS: AC fluid from 15 patients with temporal AC was included in this study. In the AC protein comparison experiment, AC fluid from 14 patients was digested, analyzed by LC-MS/MS using a semi-quantitative label-free approach and the data were compared by principal component analysis (PCA) to gain knowledge of protein homogeneity of AC. In the AC proteome evaluation experiment, AC fluid from 11 patients was pooled, digested, and fractionated by SCX chromatography prior to analysis by LC-MS/MS. Proteins identified were compared to published databases of proteins identified from CSF and plasma. AC fluid proteins not found in these two databases were experimentally searched for in lumbar CSF taken from neurologically-normal patients, by a targeted protein identification approach called MIDAS (Multiple Reaction Monitoring (MRM) initiated detection and sequence analysis). RESULTS: We did not identify systematic trends or grouping of data in the AC protein comparison experiment, implying low variability between individual proteomic profiles of AC.In the AC proteome evaluation experiment, we identified 199 proteins. When compared to previously published lists of proteins identified from CSF and plasma, 15 of the AC proteins had not been reported in either of these datasets. By a targeted protein identification approach, we identified 11 of these 15 proteins in pooled CSF from neurologically-normal patients, demonstrating that the majority of abundant proteins in AC fluid also can be found in CSF. Compared to plasma, as many as 104 proteins in AC were not found in the list of 3017 plasma proteins. CONCLUSIONS: Based on the protein content of AC fluid, our data indicate that temporal AC is a homogenous condition, pointing towards a similar AC filling mechanism for the 14 patients examined. Most of the proteins identified in AC fluid have been identified in CSF, indicating high similarity in the qualitative protein content of AC to CSF, whereas this was not the case between AC and plasma. This indicates that AC is filled with a liquid similar to CSF. As far as we know, this is the first proteomics study that explores the AC fluid proteome.

Arachnoid cysts do not contain cerebrospinal fluid: A comparative chemical analysis of arachnoid cyst fluid and cerebrospinal fluid in adults.

BACKGROUND: Arachnoid cyst (AC) fluid has not previously been compared with cerebrospinal fluid (CSF) from the same patient. ACs are commonly referred to as containing "CSF-like fluid". The objective of this study was to characterize AC fluid by clinical chemistry and to compare AC fluid to CSF drawn from the same patient. Such comparative analysis can shed further light on the mechanisms for filling and sustaining of ACs. METHODS: Cyst fluid from 15 adult patients with unilateral temporal AC (9 female, 6 male, age 22-77y) was compared with CSF from the same patients by clinical chemical analysis. RESULTS: AC fluid and CSF had the same osmolarity. There were no significant differences in the concentrations of sodium, potassium, chloride, calcium, magnesium or glucose. We found significant elevated concentration of phosphate in AC fluid (0.39 versus 0.35 mmol/L in CSF; p = 0.02), and significantly reduced concentrations of total protein (0.30 versus 0.41 g/L; p = 0.004), of ferritin (7.8 versus 25.5 ug/L; p = 0.001) and of lactate dehydrogenase (17.9 versus 35.6 U/L; p = 0.002) in AC fluid relative to CSF. CONCLUSIONS: AC fluid is not identical to CSF. The differential composition of AC fluid relative to CSF supports secretion or active transport as the mechanism underlying cyst filling. Oncotic pressure gradients or slit-valves as mechanisms for generating fluid in temporal ACs are not supported by these results.

Increased NKCC1 expression in arachnoid cysts supports secretory basis for cyst formation.

Arachnoid cysts (AC) are filled with liquid very similar to cerebrospinal fluid (CSF). The mechanisms of fluid accumulation have remained unknown; previous studies have however indicated both fluid secretion and a one-way valve as a mechanism. If the filling was caused by fluid secretion, mechanisms similar to those underlying CSF production would be anticipated. We have investigated the expression levels of all genes known to be involved in mammalian CSF production in surgically removed AC. Based on mRNA microarray analysis of AC and normal arachnoid tissue, we extracted the RNA expression profiles of all genes known to code for proteins involved in CSF production. A selection of genes was further investigated with quantitative real-time polymerase chain reaction (qRT-PCR). For selected CSF production proteins, electron microscopic immunogold techniques (EM) and Western blots were performed. Seven genes were expressed in both cysts and controls. The gene encoding the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 was significantly up-regulated in AC. Gene expression data were supported by Western blot. EM demonstrated NKCC1 expressed at the plasma membranes of the cyst-lining cells. This result points at secretion as the main mechanism of cyst filling, and NKCC1 as the key candidate of fluid transport. Based on these findings, we hypothesize that selective NKCC1 inhibitors could be used in preventing expansion of temporal AC.

Microarray-based gene expression profiling and DNA copy number variation analysis of temporal fossa arachnoid cysts.

BACKGROUND: Intracranial arachnoid cysts (AC) are membranous sacs filled with CSF-like fluid that are commonly found in the temporal fossa. The majority of ACs are congenital. Typical symptoms are headache, dizziness, and dyscognition. Little is known about genes that contribute to the formation of the cyst membranes. METHODS: In order to identify differences in gene expression between normal arachnoid membrane (AM) and cyst membrane, we have performed a high-resolution mRNA microarray analysis. In addition we have screened DNA from AC samples for chromosomal duplications or deletions using DNA microarray-based copy number variation analysis. RESULTS: The transcriptome consisting of 33096 gene probes showed a near-complete similarity in expression between AC and AM samples. Only nine genes differed in expression between the two tissues: ASGR1, DPEP2, SOX9, SHROOM3, A2BP1, ATP10D, TRIML1, NMU were down regulated, whereas BEND5 was up regulated in the AC samples. Three of the AC samples had unreported human DNA copy number variations, all DNA gains. CONCLUSIONS: Extending results of previous anatomical studies, the present study has identified a small subset of differentially expressed genes and DNA alterations in arachnoid cysts compared to normal arachnoid membrane.

Location, sidedness, and sex distribution of intracranial arachnoid cysts in a population-based sample.

OBJECT: The aim of this study was to examine the distribution of intracranial arachnoid cysts in a large and unselected patient population with special emphasis on sidedness and sex distribution. METHODS: In total, 299 patients with 305 arachnoid cysts were studied. These patients were consecutively referred to our department during a 20-year period from a well-defined geographical area with a stable population. RESULTS: There was a strong predilection (198 patients [66.2%]) for intracranial arachnoid cysts in the temporal fossa. Forty-two patients had cysts overlying the frontal convexity, 36 had cysts in the posterior fossa, and 23 patients had cysts in other, different locations. Of 269 cysts with clearly unilateral distribution, 163 were located on the left side and 106 on the right side. This difference resulted from the marked preponderance of temporal fossa cysts on the left side (left-to-right ratio 2.5:1; p < 0.0001 [adjusted < 0.0005]). For cysts in the cerebellopontine angle (CPA), there was preponderance on the right side (p = 0.001 [adjusted = 0.005]). Significantly more males than females had cysts in the temporal fossa (p = 0.002 [adjusted = 0.004]), whereas in the CPA a significant female preponderance was found (p = 0.016 [adjusted = 0.032]). For all other cyst locations, there was no difference between the 2 sexes. CONCLUSIONS: Arachnoid cysts have a strong predilection for the temporal fossa. There is a sex dependency for some intracranial locations of arachnoid cysts, with temporal cysts occurring more frequently in men, and CPA cysts found more frequently in women. Furthermore, there is a strong location-related sidedness for arachnoid cysts, independent of patient sex. These findings and reports from the literature suggest a possible genetic component in the development of some arachnoid cysts.

Differences in anatomical distribution, gender, and sidedness between ruptured and unruptured intracranial aneurysms in a defined patient population.

BACKGROUND: Working with patients with intracranial aneurysms, we have developed a clinical suspicion that there may be differences in the rupture rate of aneurysms depending on the aneurysm's anatomical location. The aim of the study was to examine the anatomical distribution of ruptured and unruptured intracranial aneurysms in a defined population. METHOD: We retrospectively included all patients with an aneurysm treated in our institution between 1 January 1990 and 31 December 1999, and collected the relevant data from the individual patient files. With the Koivisto categories for aneurysm location, we gathered the aneurysms into four categories: ACA, MCA, ICA, and VBA. FINDINGS: Four hundred forty-four aneurysms were included in the study: 361 in SAH patients and 83 in patients without SAH. ACA aneurysms were over-represented in the ruptured group (36.0% vs. 9.6%, p < 0.0001). MCA aneurysms were more frequent in the unruptured group (51.8% vs. 29.6%, p < 0.0002). Ruptured ACA aneurysms were over-represented among males (p < 0.0001), whereas ruptured ICA aneurysms were more frequent among females (p < 0.0001). Ruptured aneurysms in the posterior circulation were more frequently found on the left side (p < 0.0001). CONCLUSION: This study shows that the anatomical distribution of aneurysms is different in SAH patients compared with patients with unruptured aneurysms. Haemodynamic features of the vessel of origin may explain the differences we have found. Furthermore, this study suggests that it is of particular importance to treat patients with incidentally found ACA aneurysms.