Assessing the neuroanatomy knowledge and spatial ability of radiotherapy technologist undergraduates using an interactive volumetric simulation tool-the RadioLOG project.

OBJECTIVE: To assess the use of a volumetric image display simulation tool (VDST) for the evaluation of applied radiological neuroanatomy knowledge and spatial understanding of radiotherapy technologist (RTT) undergraduates. METHODS: Ninety-two third-year RTT students from three French RTT schools took an examination using software that allows visualization of multiple volumetric image series. To serve as a reference, 77 first- and second-year undergraduates, as well as ten senior neuroradiologists, took the same examination. The test included 13 very-short-answer questions (VSAQ) and 21 exercises in which examinees positioned markers onto preloaded brain MR images from a healthy volunteer. The response time was limited. Each correct answer scored 100 points, with a maximum possible test score of 3,400 (VSAQ = 1,300; marker exercise = 2,100). Answers were marked automatically for the marker positioning exercise and semi-automatically for the VSAQs against prerecorded expected answers. RESULTS: Overall, the mean test score was 1,787 (150-3,300) and the standard deviation was 781. Scores were highly significantly different between all evaluated groups (p < 0.001). The interoperator reproducibility was 0.90. All the evaluated groups could be discriminated by VSAQ, marker, and overall total scores independently (p ≤ 0.0001 to 0.001). The test was able to discriminate between the three schools either by VSAQ scores (p < 0.001 to 0.02) or by overall total score (p < 0.001 to 0.05). CONCLUSION: This software is a high-quality evaluation tool for the assessment of radiological neuroanatomy knowledge and spatial understanding in RTT undergraduates. KEY POINTS: • This VDST allows volumetric image analysis of MR studies. • A high reliability test could be created with this tool. • Test scores were strongly associated with the examinee expertise level.

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.

The olfactory fascia: an evo-devo concept of the fibrocartilaginous nose.

PURPOSE: Evo-devo is the science that studies the link between evolution of species and embryological development. This concept helps to understand the complex anatomy of the human nose. The evo-devo theory suggests the persistence in the adult of an anatomical entity, the olfactory fascia, that unites the cartilages of the nose to the olfactory mucosa. METHODS: We dissected two fresh specimens. After resecting the superficial tissues of the nose, dissection was focused on the disarticulation of the fibrocartilaginous noses from the facial and skull base skeleton. RESULTS: Dissection shows two fibrocartilaginous sacs that were invaginated side-by-side in the midface and attached to the anterior skull base. These membranous sacs were separated in the midline by the perpendicular plate of the ethmoid. Their walls contained the alar cartilages and the lateral expansions of the septolateral cartilage, which we had to separate from the septal cartilage. The olfactory mucosa was located inside their cranial ends. CONCLUSION: The olfactory fascia is a continuous membrane uniting the nasal cartilages to the olfactory mucosa. Its origin can be found in the invagination and differentiation processes of the olfactory placodes. The fibrous portions of the olfactory fascia may be described as ligaments that unit the different components of the olfactory fascia one to the other and the fibrocartilaginous nose to the facial and skull base skeleton. The basicranial ligaments, fixing the fibrocartilaginous nose to the skull base, represent key elements in the concept of septorhinoplasty by disarticulation.

CT-guided percutaneous cyanoacrylate injection targeting the spinal cerebrospinal fluid leak: a potential therapeutic option for spontaneous intracranial hypotension.

BACKGROUND: We report the first case series of spontaneous intracranial hypotension (SIH) patients who underwent CT-guided percutaneous cyanoacrylate injection targeting the cerebrospinal fluid (CSF) leak. METHODS: A retrospective analysis was performed for all consecutive cases of SIH patients with CSF leak confirmed on CT myelography, treated by CT-guided percutaneous cyanoacrylate injection at our institution from 2016 to 2022. On pretreatment brain and spine MRIs, we analyzed signs of SIH according to the Bern score, and dichotomized cases into positive/negative for spinal longitudinal extradural CSF collection (SLEC-P or SLEC-N). The leaks detected on CT myelography were classified into three types according to Schievink et al. We collected the Headache Impact Test 6 (HIT-6) scores throughout a 6-month follow-up, with a brain CT scan at each visit. RESULTS: 11 patients were included (mean age 48.4 years, six men). Five SLEC-P type 1, three SLEC-P type 2, and three SLEC-N type 3 leaks were identified. All patients had significant signs of SIH on pretreatment brain MRI (mean Bern score 7.8±1.1). Six patients underwent a foraminal puncture, and five patients had a cervical epidural approach. Two patients experienced mild and transient locoregional pain after cervical epidural injection. Mean HIT-6 score at baseline was 66.8±3.2 and at the 6-month follow-up was 38±3.6 (P<0.001). All patients achieved improvement in their symptoms, with 82% of them (9/11) having complete resolution of headaches and SIH findings on CT scans at 6 months. No clinical worsening or recurrence was observed. CONCLUSIONS: CT-guided percutaneous cyanoacrylate injection may be a potential therapeutic option for the different types of CSF leak causing SIH.

Local anesthesia versus general anesthesia during endovascular therapy for acute stroke: a propensity score analysis.

BACKGROUND: To date, the choice of optimal anesthetic management during endovascular therapy (EVT) of acute ischemic stroke patients remains subject to debate. We aimed to compare functional outcomes and complication rates of EVT according to the first-line anesthetic management in two comprehensive stroke centers: local anesthesia (LA) versus general anesthesia (GA). METHODS: Retrospective analysis of prospectively collected databases, identifying all consecutive EVT for strokes in the anterior circulation performed between January 1, 2018 and December 31, 2018 in two EVT-capable stroke centers. One center performed EVT under LA in the first intention, while the other center systematically used GA. Using propensity score analysis, the two groups underwent 1:1 matching, then procedural metrics, complications, and clinical outcomes were compared. Good outcome was defined as 90 days modified Rankin Scale (mRS) ≤2, and successful recanalization as modified Thrombolysis In Cerebral Ischemia (mTICI) 2b-3. RESULTS: During the study period, 219 patients were treated in the LA center and 142 in the GA center. Using the propensity score, 97 patients from each center were matched 1:1 according to the baseline characteristics. Local anesthesia was associated with a significantly lower proportion of good outcome (36.1% vs 52.0%, OR 0.53, 95% CI 0.33 to 0.87; p=0.039), lower rate of successful recanalization (70.1% vs 95.8%, OR 0.13, 95% CI 0.04 to 0.39; p<0.001), and more procedural complications (14.4% vs 3.0%, OR 3.44, 95% CI 1.09 to 14.28; p=0.018). There were no significant differences in 90-day mortality or symptomatic hemorrhagic transformation rates. CONCLUSIONS: In this study, systematic use of GA for stroke EVT was associated with better clinical outcomes, higher recanalization rates, and fewer procedural complications compared with patients treated under LA as the primary anesthetic approach.

Effect of emergent carotid stenting during endovascular therapy for acute anterior circulation stroke patients with tandem occlusion: A multicenter, randomized, clinical trial (TITAN) protocol.

BACKGROUND AND HYPOTHESIS: There is no consensus on the optimal endovascular management of the extracranial internal carotid artery steno-occlusive lesion in patients with acute ischemic stroke due to tandem occlusion. We hypothesized that intracranial mechanical thrombectomy plus emergent internal carotid artery stenting (and at least one antiplatelet therapy) is superior to intracranial mechanical thrombectomy alone in patients with acute tandem occlusion. STUDY DESIGN: TITAN is an investigator-initiated, multicenter, prospective, randomized, open-label, blinded-endpoint (PROBE) study. Eligibility requires a diagnosis of acute ischemic stroke, pre-stroke modified Rankin Scale (mRS)≤2 (no upper age limit), National Institutes of Health Stroke Scale (NIHSS)≥6, Alberta Stroke Program Early Computed Tomography Score (ASPECTS)≥6, and tandem occlusion on the initial catheter angiogram. Tandem occlusion is defined as large vessel occlusion (intracranial internal carotid artery , M1 and/or M2 segment) and extracranial severe internal carotid artery stenosis ≥90% (NASCET) or complete occlusion. Patients are randomized in two balanced parallel groups (1:1) to receive either intracranial mechanical thrombectomy plus internal carotid artery stenting (and at least one antiplatelet therapy) or intracranial mechanical thrombectomy alone within 8 h of stroke onset. Up to 432 patients are randomized after tandem occlusion confirmation on angiogram. STUDY OUTCOMES: The primary outcome measure is complete reperfusion rate at the end of endovascular procedure, assessed as a modified Thrombolysis in Cerebral Infarction (mTICI) 3, and ≥4 point decrease in NIHSS at 24 h. Secondary outcomes include infarct growth, recurrent clinical ischemic event in the ipsilateral carotid territory, type and dose of antiplatelet therapy used, mRS at 90 (±15) days and 12 (±1) months. Safety outcomes are procedural complications, stent patency, intracerebral hemorrhage, and death. Economics analysis includes health-related quality of life, and costs utility comparison, especially with the need or not of endarterectomy. DISCUSSION: TITAN is the first randomized trial directly comparing two types of treatment in patients with acute ischemic stroke due to anterior circulation tandem occlusion, and especially assessing the safety and efficacy of emergent internal carotid artery stenting associated with at least one antiplatelet therapy in the acute phase of stroke reperfusion. TRIAL REGISTRATION: ClinicalTrials.gov NCT03978988.

A direct aspiration first pass technique with the new ARC catheter for thrombectomy of large vessel occlusion strokes: A multicenter study.

BACKGROUND AND PURPOSE: A direct aspiration first pass technique involves first-line aspiration to remove the thrombus through a large-bore aspiration catheter in large vessel strokes. The aim of this study was to assess safety and clinical outcomes with a direct aspiration first pass technique using the new ARC catheter. METHODS: A retrospective analysis of prospectively collected data from three university hospitals was performed between June 2016 and May 2018. The following parameters of all acute ischemic stroke interventions using the ARC catheter were analyzed: use of intravenous thrombolysis, National Institutes of Health Stroke Scale scores at presentation and discharge, successful reperfusion (modified Thrombolysis in Cerebral Infarction 2b-3), procedure duration, procedure-related complications and 90-day clinical outcome (modified Rankin Scale score). RESULTS: In total, 41 patients were included in the study and anterior circulation occlusion was noted in 35 (85%). The median National Institutes of Health Stroke Scale at admission was 18 and prior intravenous thrombolysis was administered in 35 patients (85%). Only six (15%) patients required the use of a rescue stent retriever. Successful reperfusion was achieved in 40 patients (98%) with a median procedure time of 32 minutes. No catheter-related complications were observed. Symptomatic intracerebral hemorrhage occurred in one patient (2%). Median National Institutes of Health Stroke Scale at discharge was 3; 49% were independent and 10% died at 90 days. CONCLUSIONS: In the present study, the ARC catheter allowed a 98% successful reperfusion rate. The complication rate was in line with those of previous a direct aspiration first pass technique publications.

Impact of Emergent Cervical Carotid Stenting in Tandem Occlusion Strokes Treated by Thrombectomy: A Review of the TITAN Collaboration.

Introduction: Endovascular therapy has been shown to be an effective and safe treatment for tandem occlusion. The endovascular therapeutic strategies for tandem occlusions strokes have not been adequately evaluated and the best approach is still controversial. The TITAN (Thrombectomy in TANdem occlusions) registry was a result of a collaborative effort to identify the best therapeutic approach for acute ischemic stroke due to tandem lesion. In this review, we aim to summarize the main findings of the TITAN study and discuss the challenges of treatment for tandem occlusion in the era of endovascular thrombectomy. Methods: A review of the data from the multicenter international observational and non-randomized TITAN registry was performed. The TITAN registry included acute ischemic stroke patients with tandem lesions (proximal intracranial occlusion and cervical carotid artery occlusion or stenosis>90%) who were treated with thrombectomy with or without carotid artery stenting. Results: Prior intravenous thrombolysis and emergent cervical carotid stenting were associated with higher reperfusion (mTICI 2b-3 and mTICI 3) rates at the end of the intervention. Poor outcome did not occur more frequently after stenting than after conservative treatment of the cervical carotid lesion. Emergent carotid stenting with antithrombotic agents and intracranial thrombectomy yielded higher reperfusion rate and good outcome (90 day mRS 0-2) compared to other strategies (carotid artery stenting and thrombectomy without antithrombotic, angioplasty and thrombectomy, or thrombectomy alone). Pretreatment intravenous thrombolysis was not associated with increased risk of hemorrhagic complications. Likewise, periprocedural unfractionated heparin did not modify the efficacy and safety results. Etiology of carotid artery lesion (atherosclerosis vs. dissection) did not emerge as predictor of outcome or recanalization. Conclusion: Emergent stenting of the cervical carotid lesion with antithrombotic agents in conjunction to thrombectomy appears to be the best treatment strategy for acute ischemic strokes with tandem lesions. These findings will be further investigated in the ongoing randomized controlled TITAN trial.

Basilar Perforator Aneurysms: Presentation of 4 Cases and Review of the Literature.

OBJECTIVE: Basilar perforator aneurysms (BPAs) are rare lesions that present a therapeutic challenge. We present 4 cases of ruptured BPAs treated either conservatively or by flow diverter deployment and review the literature. METHODS: Patients (age 78, 59, 53, and 62 years) presented with World Federation of Neurological Societies grade I-IV and Fisher grade 3-4 subarachnoid hemorrhage. Initial angiography results were normal in 3 patients and necessitated a second angiography. BPA diameter was 0.5-3 mm; BPAs were located in the mid-third of the basilar artery in 2 patients and the upper third in 2 patients. RESULTS: All patients were managed conservatively. One patient experienced rebleeding 10 days after initial ictus, which required the deployment of a flow diverter in the basilar artery. One patient developed a severe spontaneous pontine ischemic stroke with severe quadriparesis and refused further imaging. He was clinically stable at 1-year clinical follow-up. The other 3 patients showed complete resolution of BPAs on control follow-up imaging. CONCLUSIONS: Ruptured BPAs are rare lesions that may heal spontaneously or be associated with spontaneous ischemic brainstem stroke or rerupture. These lesions can be managed conservatively initially with flow diverter deployment the most suitable therapeutic alternative in selected cases. Larger studies are needed to fully understand the natural history and refine the therapeutic strategy for these lesions.

Ex vivo magnetic resonance angiography to explore placental vascular anatomy.

INTRODUCTION: A normal placenta development is crucial for a successful pregnancy. In case of major obstetric complications such as intra-uterine growth restriction, the placental vascularization morphological alteration at macroscopic level is less known than that at microscopic scale. Ex vivo MRA has the potential to visualize whole fresh human placental vasculature fast and efficiently but can be hampered by contrast agent extravasation problem. This study aimed to provide an optimized ex vivo MRA protocol to acquire understanding of global human placenta vasculature morphology. METHODS: Six fresh normal human placentas were imaged with two contrast agents (i.e. Gd-chelate and pump oil) using different imaging parameters on a 3T clinical MR scanner (GE). The contrast to noise ratio, signal to noise ratio and enhancement efficiency were assessed in order to decide which contrast agent and imaging protocol was better. In the end, morphology indices were measured based on the 3D vasculature models reconstructed from the placentas imaged with the optimized protocol. RESULTS: With the same imaging parameters, the CNR and the enhancement efficiency of images enhanced with pump oil were superior to those using Gd-chelate. Enhanced by pump oil, an optimized ex vivo MRA protocol was determined, leading to a clear 3D visualization and reconstruction of human placenta vascularization. DISCUSSION: The proposed ex vivo MRA method is easy to manipulate, and can be used to investigate the human placental vasculature morphology. The acquired data are of good quality and can be used for characterization of placenta vascularization morphology.

Perioperative Bioccipital Watershed Strokes in Bilateral Fetal Posterior Cerebral Arteries During Spinal Surgery.

BACKGROUND: Vision loss due to cerebral infarction during spinal surgery is less described. Intraoperative hypotension would be a leading cause. Patients with variation of the circle of Willis could be more prone to present stroke in this context, but reports are lacking to sustain the theory. Bilateral occipital watershed ischemic strokes have never been described before. We report the case of a patient with a fetal origin of both posterior cerebral arteries (PCAs), presenting this particular anatomic stroke following lumbar laminectomy surgery for spinal stenosis during which intraoperative hypotension was observed. We discuss how this common anomaly associated with intraoperative hypotension could have promoted this serious complication. CASE DESCRIPTION: A 55-year-old man woke up with cortical blindness after he had undergone lumbar surgery during which a marked decrease in blood pressure had occurred. Magnetic resonance imaging revealed bilateral symmetric infarctions of the occipital lobes in the distal territory of both PCAs and smaller anterior watershed ischemic strokes, suggesting a hemodynamic mechanism. Extended investigations, including conventional angiography, failed to find any cause of stroke but revealed bilateral fetal PCAs supplied by internal carotid arteries only. Two years later, the patient has not recovered and remains severely visually impaired. CONCLUSIONS: The standing hypothesis would be posterior low-flow infarctions resulting from intraoperative hypotension on a variation of the circle of Willis more prone to decrease in cerebral blood flow. Moreover, this case supports the hypothesis of vascular insufficiency due to intraoperative hypotension as cause of stroke during spinal surgery.

Three Cases of Ruptured Basilar Artery Dissection: From Diagnosis to Endovascular Treatment.

BACKGROUND: Ruptured basilar artery dissections are rare, and prognosis is often disastrous. CASE DESCRIPTION: We report 3 recent cases of ruptured dissection from imaging diagnosis to endovascular treatment, presenting 3 different types of dissection and 3 different treatment approaches. These 3 patients presented major subarachnoid hemorrhage (Fisher grade 4): 2 of them were in a coma (World Federation of Neurosurgical Societies Grading System [WFNS] 5), and 1 patient presented with headache only (WFNS 1). Two of the 3 dissections presented a dilated pseudoaneurysm responsible for the bleeding (1 large and 1 small), and the remaining dissection was extensive. The dissection with the larger pseudoaneurysm was treated with coils, resulting in early recanalization requiring another endovascular treatment with coils and a flow diverter stent. The patient with the small pseudoaneurysm was treated with a flow diverter only. These 2 patients had a favorable outcome. The remaining patient with a large tear of the basilar artery had 3 overlapping stents, and fatal rebleeding occurred prematurely. CONCLUSIONS: These 3 cases illustrate different patient management strategies. We discuss this challenging condition and the current position of endovascular therapeutic techniques.

Successful Treatment of Spontaneous Intracranial Hypotension by Plugging the Cerebrospinal Fluid Leak with Percutaneous Cyanoacrylate Injection: A Report of 2 Cases.

Spontaneous intracranial hypotension (SIH) is a well-known, but under- or misdiagnosed, condition caused by cerebrospinal fluid leak resulting from idiopathic dural breach. Blind lumbar epidural blood patch is an effective treatment in most cases, but occasionally, even targeted epidural blood patch fails to lead to improvement. In these cases, the cerebrospinal fluid leak is usually repaired surgically, especially for large dural breaches (>5 mm), once the site has been identified by imaging techniques (magnetic resonance myelography/computed tomography [CT] myelography/isotopic transit). We describe a less invasive percutaneous technique consisting of direct puncture into the epidural space with a 25-G needle to access the injection site under CT control. We report 2 cases with good technical and clinical outcome after 1 and 8 years of follow-up (clinical evaluation and brain imaging control by CT). The technique we describe here is of high interest in refractory SIH or for the serious form of the disease, before considering surgical repair. Further prospective studies are required to provide general guidelines in treatment options for patients with SIH.

Developmental anatomy of the liver from computerized three-dimensional reconstructions of four human embryos (from Carnegie stage 14 to 23).

BACKGROUND & AIM: Some aspects of human embryogenesis and organogenesis remain unclear, especially concerning the development of the liver and its vasculature. The purpose of this study was to investigate, from a descriptive standpoint, the evolutionary morphogenesis of the human liver and its vasculature by computerized three-dimensional reconstructions of human embryos. MATERIAL & METHODS: Serial histological sections of four human embryos at successive stages of development belonging to three prestigious French historical collections were digitized and reconstructed in 3D using software commonly used in medical radiology. Manual segmentation of the hepatic anatomical regions of interest was performed section by section. RESULTS: In this study, human liver organogenesis was examined at Carnegie stages 14, 18, 21 and 23. Using a descriptive and an analytical method, we showed that these stages correspond to the implementation of the large hepatic vascular patterns (the portal system, the hepatic artery and the hepatic venous system) and the biliary system. CONCLUSION: To our knowledge, our work is the first descriptive morphological study using 3D computerized reconstructions from serial histological sections of the embryonic development of the human liver between Carnegie stages 14 and 23.

Human developmental anatomy: microscopic magnetic resonance imaging (µMRI) of four human embryos (from Carnegie Stage 10 to 20).

BACKGROUND AND AIM: Technological advances in the field of biological imaging now allow multi-modal studies of human embryo anatomy. The aim of this study was to assess the high magnetic field µMRI feasibility in the study of small human embryos (less than 21mm crown-rump) as a new tool for the study of human descriptive embryology and to determine better sequence characteristics to obtain higher spatial resolution and higher signal/noise ratio. METHODS: Morphological study of four human embryos belonging to the historical collection of the Department of Anatomy in the Faculty of Medicine of Reims was undertaken by µMRI. These embryos had, successively, crown-rump lengths of 3mm (Carnegie Stage, CS 10), 12mm (CS 16), 17mm (CS 18) and 21mm (CS 20). Acquisition of images was performed using a vertical nuclear magnetic resonance spectrometer, a Bruker Avance III, 500MHz, 11.7T equipped for imaging. RESULTS: All images were acquired using 2D (transverse, sagittal and coronal) and 3D sequences, either T1-weighted or T2-weighted. Spatial resolution between 24 and 70µm/pixel allowed clear visualization of all anatomical structures of the embryos. CONCLUSION: The study of human embryos µMRI has already been reported in the literature and a few atlases exist for educational purposes. However, to our knowledge, descriptive or morphological studies of human developmental anatomy based on data collected these few µMRI studies of human embryos are rare. This morphological noninvasive imaging method coupled with other techniques already reported seems to offer new perspectives to descriptive studies of human embryology.