New semi-analytical method for fast transcranial ultrasonic field simulation.

Objective.To optimize and ensure the safety of ultrasound brain therapy, personalized transcranial ultrasound simulations are very useful. They allow to predict the pressure field, depending on the patient skull and probe position. Most transcranial ultrasound simulations are based on numerical methods which have a long computation time and a high memory usage. The goal of this study is to develop a new semi-analytical field computation method that combines realism and computation speed.Approach.Instead of the classic ray tracing, the ultrasonic paths are computed by time of flight minimization. Then the pressure field is computed using the pencil method. This method requires a smooth and homogeneous skull model. The simulation algorithm, so-called SplineBeam, was numerically validated, by comparison with existing solvers, and experimentally validated by comparison with hydrophone measured pressure fields through anex vivohuman skull.Main results.SplineBeam simulated pressure fields were close to the experimentally measured ones, with a focus position difference of the order of the positioning error and a maximum pressure difference lower than 6.02%. In addition, for those configurations, SplineBeam computation time was lower than another simulation software, k-Wave's, by two orders of magnitude, thanks to its capacity to compute the field only at the focal spot.Significance.These results show the potential of this new method to compute fast and realistic transcranial pressure fields. The combination of this two assets makes it a promising tool for real time transcranial pressure field prediction during ultrasound brain therapy interventions.

Which centers should be authorized to treat craniosynostosis? A plea for quality and not for quantity.

BACKGROUND: In centers for craniosynostosis surgery, the volume of activity does not necessarily reflect the quality of the treatment. OBJECTIVE: Our aim was to analyze a retrospective series of patients over a period of 6 years in a low-volume craniosynostosis surgery center, and to study indicators that reflect the quality of treatment. PATIENTS AND METHODS: The analysis included all patients who underwent a craniofacial surgery for all forms of craniosynostosis during the period 2012-2017 (annual follow-up for 4 years). Data on the type of synostosis, sex, age, weight, type of surgery, duration of surgery, blood transfusion, postinterventional care, and total length of hospital stay were collected. Medical and surgical complications were recorded using the Leeds classification. RESULTS: Overall, 42 patients (33 male; 23 cases of scaphocephaly, 13 cases of trigonocephaly, 4 cases of coronal plagiocephaly, 1 case of lambdoid plagiocephaly, and 1 case of brachycephaly) underwent craniofacial surgery with a median age of 7.4 months [4.8; 10.4] and a mean weight of 8.40 ± 1.92 kg at surgery. The median hospital stay was 7 days [6;7] with 1 day in the postinterventional care unit for 83% of patients. The global complication rate was 12% (95% CI: 4%-26%) with three minor cutaneous and two major (cardiovascular and septic) complications. CONCLUSION: Complication rates reflect the quality of care in a center that treats craniosynostosis much more than do the number of procedures, mean hospital stay, and blood transfusion rates. It is essential to define new indicators capable of measuring the quality of life linked to surgical procedures and of using them to assess the competence of a center.

Results of a French pilot database of standard of care of chronic subdural hematoma.

BACKGROUND: A registry of chronic subdural hematoma does not exist in France yet. OBJECTIVE: To present a monocentric pilot project of a French registry of surgical management of chronic subdural hematoma. METHOD: A monocentric pseudonymized formal database was created. From May 2020 to May 2021, all patients undergoing surgical evacuation of chronic subdural hematoma were entered into the database. RESULTS: One hundred and twenty four surgeries from 113 patients were entered in the database. Patients' demographic and surgical data as well as follow-up are described. CONCLUSION: A local database is easy to implement. We propose a national registry of chronic subdural hematoma management.

Retreatment of previously treated intracranial aneurysm: Procedural complications and risk factors for complications.

OBJECTIVE: Intracranial aneurysm (IA) is a frequent vascular malformation that can be managed by endovascular treatment (EVT) or microsurgery. A previously treated IA can recanalize, which may require further treatment. The aim of our study was to evaluate procedural complications related to IA retreatment and their risk factors. METHODS: All patients retreated for IA between 2007 and 2017 in 4 hospitals were included. We retrospectively reviewed the frequency of procedural complications of IA retreatment, defined as death or≥1-point increase in modified Rankin score 24h after the procedure. We then screened for risk factors of procedural complications by comparing the characteristics of patients with and without complications. RESULTS: During the inclusion period, 4,997 IAs were treated in our 4 institutions. Of these, 237 (4.7%) were retreated. 29 (12.2%) had≥1 procedural complication. However, severe complications, defined as death or dependency at 1 month, occurred only in 3 patients (1.3%). The only risk factor for complications was microsurgical clipping as retreatment. CONCLUSIONS: Procedural complications during IA retreatment were frequent but, in most cases, retreatment did not lead to death or severe disability. The only risk factor for complications of IA retreatment was clipping as retreatment. However, the design of the study did not allow any conclusion to be drawn as to the optimal means of aneurysm retreatment, and further studies are needed.

Assessment of Maturational Changes in White Matter Anisotropy and Volume in Children: A DTI Study.

BACKGROUND AND PURPOSE: Anisotropy is a good indicator of white matter fascicle macrostructure and organization but the interpretation of its changes with age remains difficult. The increase of WM fascicle fractional anisotropy with time and its relationship with WM fascicle volume have never been examined during childhood. We studied the maturation of associative WM fascicles during childhood using MR imaging-based DTI. We explored whether the fractional anisotropy increase of the main WM fascicles persists beyond the period of brain growth and is related to WM fascicle volume increase. MATERIALS AND METHODS: In a series of 25 healthy children, the fractional anisotropy and volume of 15 associative WM fascicles were calculated. Several regression linear mixed models were used to study maturation parameters (fractional anisotropy, volume, and total telencephalon volume) considered as dependent variables, while age and sex were independent variables (the variable identifying the different WM fascicles was considered as a repeated measure). RESULTS: In children older than 8 years of age, WM fascicle fractional anisotropy increased with age (P value = .045) but not its volume (P value = .7) or the telencephalon volume (P value = .16). The time course of WM fascicle fractional anisotropy and volume suggested that each WM fascicle might follow a specific pattern of maturation. CONCLUSIONS: The fractional anisotropy increase of several WM fascicles after 8 years of age may not result from an increase in WM fascicle volume. It might be the consequence of other developmental processes such as myelination.

Subacute corticobasal syndrome following internal carotid endarterectomy.

The present report is of two patients who, immediately after internal carotid endarterectomy, presented with unexplained hemiplegia, despite normal findings on repeated MRI scans, which secondarily evolved into homolateral subacute corticobasal syndrome (CBS), with asymmetrical hemispheric hypometabolism and evidence of dopaminergic denervation. This prompted us to propose an hypothesis of transient cerebral hypoxia arising during the surgical clamping period that might have provoked a prolonged or permanent functional lesion of the left hemisphere and basal ganglia, with no visible infarction on MRI but only synaptic rearrangement of the neural networks, thereby revealing or exacerbating a potentially preexisting silent impairment.

Radiotherapy plus temozolomide in elderly patients with glioblastoma: a "real-life" report.

BACKGROUND: The optimization of the management for elderly glioblastoma patients is crucial given the demographics of aging in many countries. We report the outcomes for a "real-life" patient cohort (i.e. unselected) comprising consecutive glioblastoma patients aged 70 years or more, treated with different radiotherapy +/- temozolomide regimens. METHODS: From 2003 to 2016, 104 patients ≥ 70 years of age, consecutively treated by radiotherapy for glioblastoma, were included in this study. All patients were diagnosed with IDH-wild type glioblastoma according to pathological criteria. RESULTS: Our patient cohort comprised 51 female patients (49%) and 53 male. The median cohort age was 75 years (70-88), and the median Karnofsky performance status (KPS) was 70 (30-100). Five (5%) patients underwent macroscopic complete resection, 9 (9%) had partial resection, and 90 (86%), a stereotactic biopsy. The MGMT promoter was methylated in 33/73 cases (45%). Fifty-two (50%), 38 (36%), and 14 (14%) patients were categorized with RPA scores of III, IV, and I-II. Thirty-three (32%) patients received normofractionated radiotherapy (60 Gy, 30 sessions) with temozolomide (Stupp), 37 (35%) received hypofractionated radiotherapy (median dose 40 Gy, 15 sessions) with temozolomide (HFRT + TMZ), and 34 (33%) HFRT alone. Patients receiving only HFRT were significantly older, with lower KPSs. The median overall survival (OS; all patients) was 5.2 months. OS rates at 12, 18, and 24 months, were 19%, 12%, and 5%, respectively, with no statistical differences between patients receiving Stupp or HFRT + TMZ (P = 0.22). In contrast, patients receiving HFRT alone manifested a significantly shorter survival time (3.9 months vs. 5.9 months, P = 0.018). In multivariate analyses, the prognostic factors for OS were: i) the type of surgery (HR: 0.47 [0.26-0.86], P = 0.014), ii) RPA class (HR: 2.15 [1.17-3.95], P = 0.014), and iii) temozolomide use irrespective of radiotherapy schedule (HR: 0.54 [0.33-0.88], P < 0.02). MGMT promoter methylation was neither a prognostic nor a predictive factor. CONCLUSIONS: These outcomes agree with the literature in terms of optimal surgery and the use of HFRT as a standard treatment for elderly GBM patients. Our study emphasizes the potential benefit of using temozolomide with radiotherapy in a real-life cohort of elderly GBM patients, irrespective of their MGMT status.

Incidence and survival of childhood central nervous system tumors: A report of the regional registry of childhood cancers in Auvergne-Limousin.

INTRODUCTION: Central nervous system tumors (CNST) are the most lethal of solid tumors in childhood cancer. PATIENTS AND METHODS: We report incidence and survival data for all CNST (International Classification of Diseases for Oncology third edition, category III or Xa) recorded in children under 15 years of age by the Auvergne-Limousin cancer registry for the period 1986-2009. RESULTS: Annual incidence of all CNST was 3.27 per 100,000 and the male to female ratio was 0.95. Over 45.0% of CNST were glial. Astrocytomas (36.2%) showed the highest incidence for each age group except between 1 and 4 years where embryonal tumors were more common. For all CNST, no significant variation in incidence over time was observed for the evaluated period of 23 years (annual percent change: -0.4%, 95% CI, [-2.8-2.1]). Globally, 5 years overall survival was 67% [59-73] and had increased by more than 16% between 1986-1999 and 2000-2009, mainly due to better survival for astrocytomas, other gliomas, ependymomas and choroid plexus tumors (P=0.01). CONCLUSION: We report that the incidence of CNST in Auvergne-Limousin is similar to that in the literature and did not increase between 1986 and 2009. In addition, 5 years overall survival increased after 1999, especially for surgically treatable tumors.

A three-dimensional (3D) representation of pericardial cavity based on computed tomography (CT).

PURPOSE: The 3D modeling of human anatomy is more and more often used in medical education and in computer-augmented medicine. The lack of a 3D model of the pericardium has led us to its implementation. METHODS: The pericardium was reconstructed from a CT scan recording of a young, healthy subject. The anonymous CT scan data were blindly reviewed and interpreted by two independent radiologists. Stage one consisted in reconstructing the entire heart with the main afferent and efferent vessels. As the pericardial layers cannot be observed only with the CT scan, the second stage was to draw its reflection line following the most frequent model of pericardium defined in one of our prior studies. Afterwards, the epicardium had to be milled to finally create a pericardial sac area. RESULTS: Firstly, a model of one normal heart was reconstructed. Secondly, parietal and visceral layers of the pericardium have been achieved from the representation of their line of reflection. A short video shows recesses and sinuses and particularly, the transverse sinus crossed by a virtual object. CONCLUSIONS: The resulting model is subject to certain limits, including reproducibility linked to the operator, individual anatomical variation, and scanner resolution but it represents a pericardial pouch true to its more common anatomical morphology. It offers a very precise educational tool. It must be considered as the first step of an automatic segmentation and reconstruction process to modelize normal and pathological pericardium. This is also the first step before a 3D dynamic model, synchronized with heartbeats.