Geometric and Hemodynamic Analysis of the Risk of Rupture of Intracranial Aneurysms

Intracranial aneurysms are dilaNons of the walls of the cerebral arteries, their rupture causes subarachnoid haemorrhage, an enNty of high mortality and sequelae among survivors. This series of studies analyze mulNple intracranial aneurysms, anterior communicaNng artery aneurysms and rebleeding acer placement of an external ventricular drainage using computaNonal fluid dynamics methods from imaging studies of real paNents. Treatment of a proximal aneurysm, absence of asymmetry of A1 and decreased A1/A2 angles in asynchrony of A1 artery increases the theorieNcal risk of rupture. External ventricular drainage increases the wall displacement in low shear areas of the aneurysm favoring rebleeding of the aneurysm

Glioblastoma Pseudoprogression Discrimination Using Multiparametric Magnetic Resonance Imaging, Principal Component Analysis, and Supervised and Unsupervised Machine Learning

Glioblastoma; Prediction models; PseudoprogressionGlioblastoma; Models de predicció; PseudoprogressióGlioblastoma; Modelos de predicción; PseudoprogresiónBackground One of the most frequent phenomena in the follow-up of glioblastoma is pseudoprogression, present in up to half of cases. The clinical usefulness of discriminating this phenomenon through magnetic resonance imaging and nuclear medicine has not yet been standardized; in this study, we used machine learning on multiparametric magnetic resonance imaging to explore discriminators of this phenomenon. Methods For the study, 30 patients diagnosed with IDH wild-type glioblastoma operated on at both study centers in 2011–2020 were selected; 15 patients corresponded to early tumor progression and 15 patients to pseudoprogression. Using unsupervised learning, the number of clusters and tumor segmentation was recorded using gap-stat and k-means method, adjusting to voxel adjacency. In a second phase, a class prediction was carried out with a multinomial logistic regression supervised learning method; the outcome variables were the percentage of assignment, class overrepresentation, and degree of voxel adjacency. Results Unsupervised learning of the tumor in its diagnosis shows up to 14 well-differentiated tumor areas. In the supervised learning phase, there is a higher percentage of assigned classes (P < 0.01), less overrepresentation of classes (P < 0.01), and greater adjacency (55% vs. 33%) in cases of true tumor progression compared with pseudoprogression. Conclusions True tumor progression preserves the multidimensional characteristics of the basal tumor at the voxel and region of interest level, resulting in a characteristic differential pattern when supervised learning is used

Effects of external ventricular drainage decompression of intracranial hypertension on rebleeding of brain aneurysms: A fluid structure interaction study

Objectives: The treatment of hydrocephalus using external ventricular drainage (EVD) seems to favour rebleeding of an untreated ruptured aneurysm. FSI studies are valuable to study this environment. Patients and methods: From December 2014 to December 2017, 61 patients with SAH required EVD due to hydrocephalus, 6 patients had aneurysm rebleeding after the procedure. Two controls for each case was included. DSA studies were used for fluid–structure interaction simulations using two scenarios high ICP (5332 Pa) and low ICP (133 Pa). Results: Maximum displacement of the wall in HICP was 0.34 mm and 0.26 mm in rebleeding and no rebleeding cases respectively, after EVD (LICP), it was 0.36 mm and 0.27 mm. The difference after implantation of EVD (HICP-LICP) had an average of 0.01567 mm and 0.00683 mm in rebleeding and no rebleeding cases (p = 0.05). This measure in low shear areas of the aneurysm was 0.026 and 0.0065 mm in rebleeding and no rebleeding cases (p = 0.01). Effective stress in the HICP was 4.77 MPa and 3.26 MPa in rebleeding and no rebleeding cases (p = 0.25). In LICP condition, this measure was 2.28 MPa and 1.42 MPa respectively (p = 0.33). TAWSS had no significant differences in the conditions of HICP and LICP. Conclusion: Changes after EVD placement includes an increase in the wall displacement with greater differences over low shear areas, this had a strong association with rebleeding.Xunta de Galicia | Ref. POS-A/2013/161Xunta de Galicia | Ref. ED481B 2016/047-0Xunta de Galicia | Ref. ED481D 2017/01

Anaplastic Pilocytic Astrocytoma in adults: A comprehensive literature review based on 2 clinical cases

Anaplastic Pilocytic Astrocytoma (APA) is a subtype of Pilocytic Astrocytoma (PA) that appears when the tumor shows signs of anaplasia and follow an aggressive clinical course. It is a very rarely tumor, especially in older than 18 years. We made a screening of our data base to find patients who was discharged with the diagnostic of APA and we made a search in PubMed to find articles that represents this kind of tumors and realize a literature review. We present 2 cases of patients with APA diagnostic: a progression from a Pilocytic Astrocytoma in a 38 years-old woman and a 36 years-old woman with a cerebellar APA. Both patients were operated without complications and persist asymptomatic in a five- and seven-years follow-up. On the literature review we found 18 articles with a total of 84 patients and described demographic, clinical, radiological, histopathological and genetic features. To our knowledge, the pathological presentation behavior of our clinical cases is very rare and can contribute important data to the published literature.APA is more aggressive than classical PA. It is important to identify this variant for stablish the best and faster treatment options, adjuvant therapies, appropriate prognosis and active follow-up