Functional ultrasound imaging and neuronal activity: how accurate is the spatiotemporal match?

Over the last decade, functional ultrasound (fUS) has risen as a critical tool in functional neuroimaging, leveraging hemodynamic changes to infer neural activity indirectly. Recent studies have established a strong correlation between neural spike rates (SR) and functional ultrasound signals. However, understanding their spatial distribution and variability across different brain areas is required to thoroughly interpret fUS signals. In this regard, we conducted simultaneous fUS imaging and Neuropixels recordings during stimulus-evoked activity in awake mice within three regions the visual pathway. Our findings indicate that the temporal dynamics of fUS and SR signals are linearly correlated, though the correlation coefficients vary among visual regions. Conversely, the spatial correlation between the two signals remains consistent across all regions with a spread of approximately 300 micrometers. Finally, we introduce a model that integrates the spatial and temporal components of the fUS signal, allowing for a more accurate interpretation of fUS images.

Intracranial Aneurysm in Pediatric Population: A Single-Center Experience.

PURPOSE: Pediatric intracranial aneurysms (PIA) are rarer and more complex when compared to adult aneurysms. In general, the clinical presentation of PIA is due to a mass effect, but the presenting symptoms can be also related to ischemia, subarachnoid hemorrhage (SAH), or in a combination of different symptoms. This paper aimed to report a single-center experience with clinical and angiographic aspects of brain aneurysm in children. METHODS: We retrospectively reviewed our prospectively maintained database for patients with intracranial aneurysms in our institution from July 2015 to February 2021. Among these, all patients under 18 years of age submitted to a diagnostic or therapeutic procedure for an intracranial aneurysm were included. RESULTS: Twelve patients were submitted to diagnostic or therapeutic procedures in our department. Three of them had multiple aneurysms, and in total, 17 intracranial aneurysms were assessed in this study. The most frequent location was in the middle cerebral artery (7 cases/41%). Five out of twelve children (42%) presented SAH due to ruptured aneurysm. Three patients (25%) had symptoms due to the mass effect from large aneurysms, with compression of cranial nerves or brainstem. Aneurysms diameters ranged from 1.5 mm to 34 mm (mean 14.2 mm), with six aneurysms being giant and eight being nonsaccular/fusiform. Twelve aneurysms were submitted to endovascular treatment, with one treatment-related clinical complication and later death. CONCLUSION: PIAs are rare diseases that can arise from a variety of different underlying pathological mechanisms. The management of these conditions requires a detailed understanding of the pathology and a multidisciplinary approach. Despite the availability of new technologies, parent vessel occlusion remains a valid option for aneurysms in the pediatric population.

Long-Term Outcomes of Patients with Hydrocephalus Secondary to Tectal Plate Glioma versus Idiopathic Aqueductal Stenosis: Results from a Single Center.

INTRODUCTION: Tectal plate gliomas (TPG) constitute a distinct entity of benign tumors of the brain stem which show an indolent clinical course. Adequate treatment of secondary hydrocephalus is undoubtedly a major factor in the outcome. However, little is known about to what degree the tumor itself determines the long-term outcome of these patients. METHODS: We retrospectively analyzed and compared the clinical and radiological data of 16 pediatric TPG patients with data of 12 pediatric idiopathic aqueductal stenosis (IAS) patients treated in our center from 1988 to 2018. For both groups, we assessed the long-term outcome in terms of hydrocephalus management, and for the TPG group, we assessed tumor growth during follow-up. In a separate prospective part of the study, we performed a neuropsychological evaluation in a subgroup of patients using a standardized testing battery, covering intelligence, learning, memory, executive functions, and an inventory on depression. RESULTS: In the TPG group, the mean clinical and radiological follow-up was 84 and 70 months, respectively. On average, the maximum diameter of the tumor increased by 11% (p = 0.031) and the estimated tumor volume with 35% (p = 0.026) on radiological follow-up. The fronto-occipital horn ratio (FOHR) decreased by 23% on average after treatment. In the IAS group, the mean clinical and radiological follow-up was 117 and 85 months, respectively. In this group, the FOHR decreased by 21% on average. Neurocognitive testing revealed significant higher scores in the TPG group on global intelligence (TPG = 109, IAS = 85.5, U = 3, p < 0.01, z = -2.71), performance (TPG= 100, IAS = 85, U = 7, p = 0.03, z = -2.2), and verbal intelligence (TPG = 122, IAS = 91.5, U = 2, p < 0.00, z = -2.87) as well as working memory (TPG = 109.5, IAS = 77, U = 0.5, p = 0.01, z = -2.46). CONCLUSION: Our results suggest that the long-term outcome in TPG patients is acceptable and that cognition is substantially better preserved than in patients with IAS. This puts the idea of a significant contribution of the tumoral mass to disease outcome on the long term in question. Adequate and prompt management of hydrocephalus is the most important factor in long-term cognitive outcome.

Minimally Invasive Aneurysm Clipping: The Extent of the Supraorbital Approach.

BACKGROUND: The supraorbital keyhole craniotomy is a well-established minimally invasive approach for the treatment of intracranial aneurysms. However, the surgical range of exposure using this technique for treatment of intracranial aneurysms has not been studied. METHODS: We retrospectively reviewed the data of all clipped aneurysm cases using the supraorbital approach (SO) between 2006 and 2016 in our center. Most importantly, we determined the location of the treated aneurysms in the axial 2-dimensional plane, with the anterior clinoid process (ACP) as the point of reference: the ACP to aneurysm distance. Finally, we extracted data on patient age, aneurysm size, size of the craniotomy, length of hospital stay, and surgery-related complications. RESULTS: We included 142 patients for this series. A total of 170 aneurysms were clipped by means of the SO, and in 18 cases multiple aneurysms were treated during the same surgery. The mean aneurysm size was 7 mm (3.5-22 mm) and the mean craniotomy size was 28 mm (19-41 mm). The aneurysm location ranged from 14.4 mm medially to 35 mm laterally, measured with the ipsilateral ACP as the zero reference. CONCLUSIONS: Although the SO is conventionally used in the treatment of anterior circulation aneurysms, we were able to treat aneurysms over a range of 50 mm over the skull base. With its low complication risk, relatively short hospital stay, and excellent cosmetic results, SO remains a valuable treatment option for both young and aged patients.

The Value of the Middle Meningeal Artery in Cerebrovascular Bypass Surgery: An Anatomic Feasibility Study.

BACKGROUND: Over the past decade, there has been a revival and a renewed interest for cerebrovascular bypass procedures. The superficial temporal artery (STA) has its value as a reliable donor vessel; however, a possible role for the middle meningeal artery (MMA) as a donor artery is still unclear. OBJECTIVE: To assess the feasibility of using the MMA as a donor vessel in cerebrovascular surgery. METHODS: We performed cadaveric dissections on 12 fresh specimens (23 sides) after bilateral silicone injection into the internal and external carotid arteries. We compared the size, diameter, and possibility to perform a bypass to the middle cerebral artery for both the MMA and the STA. Measurements were done using an electrical caliper. Additional measurements of the MMA and STA were performed on 20 random angiograms. RESULTS: There was no statistically significant difference in diameter of the MMA at its ostium being 2.4 mm, compared to 2.7 mm for the STA ostium (t-test; P = .21). The MMA could be mobilized over 4.1 cm, whereas the STA over 8.3 cm. Finally, the mean diameter of the donor vessel at the site of the anastomosis was 1.6 mm versus 1.9 mm for MMA and STA, respectively (P = .0026). We were able to perform an MMA and middle cerebral artery anastomosis on 17 sides. CONCLUSION: These results suggest that the MMA is a potentially valuable donor vessel to be used in selected cases. The availability of a suitable MMA branch should be assessed preoperatively on the angiogram.

Accessory atlantoaxial ligament avulsion fracture of the axis: Are there any clinical implications?

Injuries to the craniocervical support structures are frequently observed in neurotrauma cases. Stability of this region is of vital importance. Literature has mainly focused on three major ligaments of the craniocervical junction: The tectorial membrane, the transverse ligament, and the alar ligaments. However, the accessory atlantoaxial ligament (ALL) also seems to be involved in craniocervical stability as shown in cadaveric specimens. Still, the biomechanical importance of this structure needs to be determined, especially in trauma settings. Here, we describe a case of isolated traumatic injury to this structure and discuss the clinical outcome. A 64-year-old polytrauma patient with a remarkable avulsion fracture at the site of the insertion of the ALL was admitted to our center. We evaluated the patient both clinical and radiological at admission, after 3 months and after 1 year. We clinically assessed the upper cervical rotational stability using the cervical flexion-rotation test. We observed no rotational instability or any other clinical repercussions at the long-term after an isolated ALL injury. This case shows that isolated traumatic damage to the ALL is possible. Unilateral damage to the ALL probably does not cause rotational instability of the craniocervical junction. In case a similar avulsion fracture is observed, we recommend performing a magnetic resonance imaging of the craniovertebral region to assess for any ligamentous lesions.

Huge familial colloid cyst of the third ventricle: An extraordinary presentation.

BACKGROUND: Since the use of computed tomography and magnetic resonance imaging, colloid cysts (CCs) are discovered more frequently and subsequently their true incidence exceeds the numbers previously estimated. In 1986, the first familial case was reported in two identical twin brothers. To date, a total of 17 of these cases have been reported, all differing in the pattern of affected family members. CASE DESCRIPTION: Here, we describe a unique presentation of a familial case and review the relevant literature on CCs and their natural history to improve our understanding of these cases. CONCLUSION: Familial CC can present in various patterns, sizes, and forms. A genetic factor is likely to be responsible in these cases, and further research is warranted to clarify this phenomenon.

Results of endoscopic third ventriculostomy in elderly patients ≥65 years of age.

INTRODUCTION: Endoscopic third ventriculostomy (ETV) has been accepted as the procedure of choice for the treatment of obstructive hydrocephalus in children and adults. The role and outcome of this procedure in the elderly has not been evaluated yet. MATERIALS AND METHODS: Over an 11-year interval we retrospectively analyzed data of patients, 65+ years of age, who underwent ETV in our center. Success of the procedure was assessed in terms of symptom relief and/or elimination of the need for shunting. Additionally pre- and postoperative ventricular volumes were estimated using Evan's index (Ei) and fronto-occipital horn ratio (FOR). In our analysis we compared the results of the elderly patients with those of the pediatric and adult age groups treated in our center. RESULTS: We obtained data of 16 elderly cases (11 males, 5 females), mean age 72.8 years (66-83 years) out of the 91 patients treated with ETV in total. The success rate was 75% in this age group; mean follow-up 18.4 months (2-55 months). In 10 patients a mass lesion was the underlying cause of hydrocephalus. Mean ventricular size reduction was 18% and 13.5% (Ei and FOR) in the success group vs. 7.6% and 6.2% in the failure group. Three out of four patients who had shunting pre-EVT, became shunt independent post-operatively. The presence of flow void over the stoma was 100% correlated with success. All 7 patients with a primary or metastatic brain tumor were able to receive radiation therapy. CONCLUSION: Also in elderly, ETV is a safe and efficient procedure, with success rates similar to the younger population. Further research is required to set up a prognostic scoring system for this age group.