Arachnoid granulations in idiopathic intracranial hypertension: Do they have an influence?

OBJECTIVE: The aim of this study was to investigate whether the relative narrowing of the dural venous sinuses by arachnoid granulations (AGs) is more pronounced in patients with idiopathic intracranial hypertension (IIH) compared to healthy controls. BACKGROUND: IIH is characterized by increased intracranial pressure, which is associated with symptoms such as headache and visual disturbances. The role of cerebral venous drainage obstruction in IIH is the subject of ongoing research. MATERIALS AND METHODS: In this retrospective case-control study, 3D contrast-enhanced magnetic resonance images of a cohort of 43 patients with IIH were evaluated for (1) the number of AGs per venous sinus and (2) the diameters of the dural venous sinuses at the site of an AG and at standardized measurement points. In addition, the minimum width of the transverse/sigmoid sinus was measured. All data were compared to the same data from a cohort of 43 control participants. RESULTS: Patients with IIH showed less relative sinus narrowing by AG compared to controls (median: 7%, interquartile range [IQR] 10% vs. 11%, IQR 9% in controls; p = 0.009). In patients with IIH, sinus diameter was larger at the site of an AG (70 ± 25 mm2) compared to its diameter at the standardized measurement point (48 ± 23 mm2; p = 0.010). In the superior sagittal sinus (SSS), patients with IIH had smaller AGs (median: 3 mm2, IQR 2 mm2 vs. 5 mm2, IQR 3 mm2 in controls; p = 0.023) while the respective sinus segment was larger (median: 69 mm2; IQR 21 mm2 vs. 52 mm2, IQR 26 mm2 in controls; p = 0.002). The right transverse sinus was narrower in patients with IIH (41 ± 21 mm vs. 57 ± 20 mm in controls; p < 0.001). CONCLUSIONS: In contrast to our hypothesis, patients with IIH showed less pronounced relative sinus narrowing by AG compared to controls, especially within the SSS, where AGs were smaller and the corresponding sinus segment wider. Smaller AGs could result in lower cerebrospinal fluid resorption, favoring the development of IIH. Conversely, the smaller AGs could also be a consequence of IIH due to backpressure in the SSS because of the narrower transverse/sigmoid sinus, which widens the SSS and compresses the AG.

Impact of an AI software on the diagnostic performance and reading time for the detection of cerebral aneurysms on time of flight MR-angiography.

PURPOSE: To evaluate the impact of an AI-based software trained to detect cerebral aneurysms on TOF-MRA on the diagnostic performance and reading times across readers with varying experience levels. METHODS: One hundred eighty-six MRI studies were reviewed by six readers to detect cerebral aneurysms. Initially, readings were assisted by the CNN-based software mdbrain. After 6 weeks, a second reading was conducted without software assistance. The results were compared to the consensus reading of two neuroradiological specialists and sensitivity (lesion and patient level), specificity (patient level), and false positives per case were calculated for the group of all readers, for the subgroup of physicians, and for each individual reader. Also, reading times for each reader were measured. RESULTS: The dataset contained 54 aneurysms. The readers had no experience (three medical students), 2 years experience (resident in neuroradiology), 6 years experience (radiologist), and 12 years (neuroradiologist). Significant improvements of overall specificity and the overall number of false positives per case were observed in the reading with AI support. For the physicians, we found significant improvements of sensitivity on lesion and patient level and false positives per case. Four readers experienced reduced reading times with the software, while two encountered increased times. CONCLUSION: In the reading with the AI-based software, we observed significant improvements in terms of specificity and false positives per case for the group of all readers and significant improvements of sensitivity and false positives per case for the physicians. Further studies are needed to investigate the effects of the AI-based software in a prospective setting.

Decompressive craniotomy in split-technique (DCST) for TBI in infants: introducing a new surgical technique to prevent long-term complications.

INTRODUCTION: Decompressive craniectomy (DC) is rarely required in infants. These youngest patients are vulnerable to blood loss, and cranial reconstruction can be challenging due to skull growth and bone flap resorption. On the other hand, infants have thin and flexible bone and osteogenic potential. MATERIAL AND METHODS: We propose a new technique called DCST, which makes use of these unique aspects by achieving decompression using the circumstance of the thin and flexible bone. We describe the surgical technique and the follow-up course over a period of 13 months. RESULTS AND CONCLUSION: In our study, DCST achieved adequate decompression and no  further repeated surgeries in accordance with decompressive craniectomy were needed afterwards.

The impact of real-time ultrasound guidance for ventricular catheter placement in cerebrospinal fluid shunts - a single center study.

Purpose Misplacement of ventricular catheters in shunt surgery occurs in 40% with freehand technique and represents therefore a risk for early shunt failure. The goal of this retrospective, single center study is to analyze the impact of real-time ultrasound guidance on ventricular catheter positioning and early outcome of shunt survival. Materials and Methods We analyzed the charts and images of all patients who underwent shunt surgery from 09/2017 to 12/2022 and compared the position of ventricular catheter by using the freehand technique and real-time ultrasound guidance. Central catheter position was graded as grade I (optimal), II (contact with ventricle structures or contralateral) and III (misplacement). Results Ventricular catheter was placed in 244 patients using real-time US-guidance and in 506 patients using freehand technique. The mean age (53.4 and 53.6 years respectively) and the preoperative frontal occipital horn ratio (FOHR; 0.47 versus 0.44) were almost equal in both groups. In the study group, grade I catheter position was achieved in 64%, grade II in 34% and grade III in 2%. The control group showed grade I position in 45%, grade II in 32% and grade III in 23% of cases (p<0.05). Early central catheter failure rate was the highest in grade III (40.5%) compared to 4% in grade I. Conclusion Our data demonstrate that real-time US-guidance lead to a significant improvement of ventricular catheter placement. In consequence early shunt revisions decrease significantly. Further prospective, randomized, and controlled studies comparing standard method to a real-time ultrasound catheter placement are required.

Delayed Internal Carotid Artery Dissection Mimicking Cerebral Vasospasms after Subarachnoid Hemorrhage: A Case Report.

BACKGROUND: Delayed cerebral ischemia (DCI) is usually caused by cerebral vasospasm (CVS). To detect DCI and CVS a cranial CT scan will be performed, but cervical vessels are not necessarily displayed. PATIENT: A 63-year-old female patient who suffered from aneurysmal subarachnoid hemorrhage (SAH) was treated at the authors' institution. After an initially unremarkable clinical course, she developed aphasia on day 11. CT angiography (CTA) and perfusion imaging revealed significant hypoperfusion of the left hemisphere. In addition, the CTA showed a subtotal stenosis of the internal carotid artery (ICA) at the level of the petrous segment, suspicious for a dissection. This was not detectable angiographically in the final control of the intervention and was also not clinically evident until day 11. Cerebral perfusion as well as the clinical symptoms normalized rapidly after stent reconstruction of the ICA. CONCLUSION: Even though CVS is the most frequent cause of hypoperfusion in patients after SAH, a periinterventional dissection can also lead to relevant stenosis and thus to a disturbed cerebral perfusion and corresponding neurological deficits. The time delay between the intervention and the clinical as well as CT-angiographical manifestation in our case is remarkable.

School of Thrombectomy-A 3-Step Approach to Perform Acute Stroke Treatment with Simulator Training and Virtual Supervision by Remote Streaming Support (RESS).

As the number of neurointerventional procedures continues to increase, so does the need for well-trained neurointerventionalists. The purpose of this work was to establish and assess a systematic 3­step approach to perform acute stroke treatment including simulator training and virtual supervision by remote streaming support (RESS). Five trainees (four men, one women) who have completed the 3­step approach have answered an 11-item questionnaire (5-point Likert scale) in order to evaluate training step 1 (simulator). Furthermore, all trainees and one supervisor (female) answered a standardized questionnaire following the initial 15 consecutive thrombectomies for each trainee, corresponding to a total of 75 thrombectomies. The simulator training yielded learning benefits and confidence gain to perform MT on patients. The RESS approach facilitated the translation during the first independently performed thrombectomies on patients. In summary, the presented 3­step approach increases the level of safety, as reported by the trainees and supervisor in this study and may enable an accelerated training of neurointerventionalists.

CNS Superficial Siderosis Mimicking a Motor Neuron Disease.

Superficial siderosis of the central nervous system (SS-CNS) is a rare condition characterized by a hemosiderin accumulation along the subpial surfaces and arises from an intermittent chronic bleeding in the subarachnoid space usually as a result of a chronic subarachnoid hemorrhage by trauma, vascular malformations, CNS tumors, or cerebral amyloid angiopathy (CAA). We present a 61-year-old male with a 12-year history of limb weakness, muscle wasting, cramps, clumsiness, progressive unsteady gait, and fine motor impairments. His medical history included the resection of a left parietal meningioma and a myxopapillary ependymoma near the conus terminalis (L3/4) at the age of 51 years. The clinical examination revealed a motor neuron syndrome with a clear bilateral wasting of the hand muscles, a diffuse atrophy of the shoulder and calf muscles, and a weakness of the arms, fingers, hips, and feet. Deep tendon reflexes were symmetrically briskly hyperactive. Standing and walking were only possible with a support. Magnetic resonance imaging of the entire neuroaxis showed progressive severe cerebral, brainstem, and spinal superficial siderosis in form of extensive hypointensities on T2-weighted gradient-echo images and susceptibility-weighted sequences. Despite a successful neurosurgical removal of the tumors and delaed medical treatment with an iron chelator for one year, we observed no clinical recovery or stability in our patient, making this case unique, and suggesting an irreversible neurodegenerative process. This case reinforces the need of including SS-CNS in the list of amyotrophic lateral sclerosis (ALS)-mimics and demonstrates the fundamental use of a complete neuraxial MRI investigation on evaluating possible ALS cases.

Sonographic assessment of the optic nerve and the central retinal artery in idiopathic intracranial hypertension.

PURPOSE: Transorbital sonography easily detects papilledema and enlarged optic nerve sheath diameters (ONSD) in IIH (idiopathic intracranial hypertension) patients. As the central retinal artery is located within the optic nerve, its hemodynamic properties might be affected by the increased pressure. In this study we assessed the diagnostic usefulness of transorbital sonography in IIH with a special focus on color Doppler imaging of the central retinal artery. IIH patients presented papilledema and enlarged ONSD. ONSD accurately predicted an increased intracranial pressure in IIH (cut-off: 5.8 mm, 81% sensitivity, 80% specificity). 24 h following therapeutic lumbar puncture ONSD diminished significantly, whereas papilledema was not changed. PSV (peak systolic velocity) and Vmean (mean flow velocity) of the central retinal artery were increased in IIH patients compared to controls. PSV accurately predicted an increase of intracranial pressure (cut-off: 11.0 cm/s, 70% sensitivity, 69% specificity). PI (pulsatility index), PSV and Vmean decreased following lumbar puncture. PSV and Vmean decreases were statistically significant for right eyes only in which the values changed to normal. In summary, besides ONSD enlargement and papilledema transbulbar sonography demonstrated an alteration of central retinal artery blood flow in IIH patients. Especially PSV might serve as valuable surrogate marker for intracranial pressure in IIH. Furthermore, the change of intra-individual central retinal arteries PI might be a valuable parameter to demonstrate response to lumbar puncture in IIH patients.

Limbic Encephalitis in Patients with Epilepsy-is Quantitative MRI Diagnostic?

PURPOSE: Limbic encephalitis (LE) is an immune-related disease with limbic symptoms, variable and asymmetric magnetic resonance imaging (MRI) aspects and antibody profiles. This study investigated the diagnostic value of quantitative relaxation times T2 (qT2) and MRI signal intensities (SI) in LE. METHODS: The prospective 3T-MRI study included 39 epilepsy patients with initially suspected LE and 20 healthy controls. Values and asymmetry indices of qT2, T2-weighted (T2-w) and proton density (PD)-w SI of manually delineated and automatically segmented amygdala and hippocampus were measured. Additionally, two raters made a blinded visual analysis on FLAIR (fluid attenuation inversion recovery) and T2-w images. RESULTS: According to diagnostic guidelines, 22 patients had probable LE and 17 patients had possible LE. The qT2 was higher (p < 0.01) in patients than in controls (mean ± SD, amygdala 98 ± 7 ms vs. 90 ± 5 ms, hippocampus 101 ± 7 ms vs. 92 ± 3 ms), but was not different between probable and possible LE or between sides (left and right). The PD-w SI and T2-w SI were lower in patients than in controls but were not different between patient subgroups or between sides. Diagnostic performance of visual analysis was relatively poor. CONCLUSIONS: Epilepsy patients with suspected LE had elevated qT2 in amygdala and hippocampus, whereas the expected T2-w SI increase was not found; however, the diagnostic value of qT2 remains questionable since it did not discriminate probable from possible LE.