Intravoxel incoherent motion magnetic resonance imaging in the assessment of brain microstructure and perfusion in idiopathic normal-pressure hydrocephalus.

PURPOSE: To determine the relationship between intravoxel incoherent motion (IVIM) MRI parameters and clinical changes post-tap test (TT) in idiopathic normal-pressure hydrocephalus (iNPH) patients. METHODS: Forty-four probable iNPH patients underwent 3 T MRI before and after TT. IVIM parameters were calculated from eight different bilateral regions of interest in basal ganglia, centrum semiovale, and corona radiata. Patients were categorized based on TT response into positive (group 1) and negative (group 2) groups. A Welch two-sample t-test was used to compare differences in D, D*, f, and ADC between the two groups, while a paired t-test was employed to assess the changes within each group before and after TT. These parameters were then correlated with clinical results. RESULTS: In the lenticular and thalamic nuclei, D value was significantly lower in the group 1 compared to group 2 both pre- and post-TT (p = 0.002 and p = 0.007 respectively). Post-TT, the positive response group exhibited a notably reduced D* value (p = 0.012) and significantly higher f values (p = 0.028). In the corona radiata and centrum semiovale, a significant post-TT reduction in D* was observed in the positive response group (p = 0.017). Within groups, the positive response cohort showed a significant post-TT increase in ADC (p < 0.001) and a decrease in D* (p = 0.007). CONCLUSION: IVIM permits the acquisition of important non-invasive information about tissue and vascularization in iNPH patients. Enhanced perfusion in the lenticular and thalamic nuclei may suggest the role of re-established microvascular and glymphatic pathways, potentially elucidating the functional improvement in motor function after TT in iNPH patients.

Clinical applicability of arterial spin labeling magnetic resonance imaging in patients with possible idiopathic normal pressure hydrocephalus: A prospective preliminary study.

PURPOSE: idiopathic Normal Pressure Hydrocephalus (iNPH) patients have a global reduction of cerebral blood flow (CBF) and Arterial Spin Label (ASL) MRI allows a global evaluation of CBF without the injection of contrast agents. This work aims to assess the qualitative evaluation agreement of ASL CBF colored maps between different neuroradiologists and by correlating these data to the Tap Test. METHODS: Thirty - seven patients with the diagnosis of possible iNPH were consecutively submitted to a diagnostic MRI on a 1.5 Tesla Magnet before and after the lumbar infusion test and the Tap Test. Twenty - seven patients improved after the Tap Test and were addressed to surgery while 10 patients did not improve. All the MRI examinations included a 3D-Pulsed ASL sequence. Two different neuroradiologists independently reviewed all ASL images. They were asked to give a score (0 not improved; 1 improved) to global perfusion image quality by comparing ASL images obtained after the Tap Test to those obtained before. Comparison between inter- and intra-reader qualitative scores were performed with Cohen's kappa. RESULTS: Inter-reader agreement between the two neuroradiologists showed that qualitative scores were attributed similarly by two readers (k = 0.83). This technique has a good PPV (90.5 %; CI 95 %, 72.7-97.1 %), NPV (50 %; CI 95 %, 34.1-65.6 %), SN (70.37 %; CI 95 %, 49.8-86.2 %) SP (80 %; CI 95 %, 44.4-97.5 %) and accuracy (73 %; CI 95 %, 55.9-86.2 %) when considered in the setting of possible iNPH patients. CONCLUSION: ASL-MRI seems to be a promising non-invasive technique in the preoperative selection of patients affected by possible iNPH.

MDS-UDPRS-III in the diagnosis of idiopathic Normal Pressure Hydrocephalus and identification of candidates for Ventriculo-Peritoneal Shunting surgery. Results from a retrospective large cohort of patients.

OBJECTIVES: To evaluate the entity of extrapyramidal signs, characterize them and evaluate the dynamics of change by the mean of MDS-UPDRS-III in iNPH patients after the TT to determine if this tool may help the diagnosis of iNPH and the identification of candidates for Ventriculo-Peritoneal Shunting. MATERIALS AND METHODS: We retrospectively collected data from 120 patients with the initial diagnosis of possible iNPH; they underwent neurological examination by the means of MDS-UPDRS-III and other scales before and after Tap Test (TT). They were then classified as defined iNPH (57), probable iNPH (35), and NOT-iNPH (28) based on the clinical response after the Tap Test and VPS. RESULTS: After the Tap Test, defined and probable iNPH groups improved by 3.35 (2.57-4.12, p < 0.001) and 3.43 (2.43-4.4, p < 0.001) points on MDS-UPDRS-III respectively; NOT-iNPH did not improve significantly on MDS-UPDRS-III and on any other variable studies. Defined iNPH also shifted significantly from asymmetric prevalence of symptoms to a more symmetric form (from 70% before to 57% after). CONCLUSION: extrapyramidal signs improved significantly after the Tap Test in definite and probable iNPH patients. MDS-UPDRS-III may be a useful complementary tool in the diagnosis of iNPH and identification of candidates for Ventriculo-Peritoneal Shunting.

Resting-state functional-MRI in iNPH: can default mode and motor networks changes improve patient selection and outcome? Preliminary report.

BACKGROUND: Idiopathic normal pressure hydrocephalus (iNPH) is a progressive and partially reversible form of dementia, characterized by impaired interactions between multiple brain regions. Because of the presence of comorbidities and a lack of accurate diagnostic and prognostic biomarkers, only a minority of patients receives disease-specific treatment. Recently, resting-state functional-magnetic resonance imaging (rs-fMRI) has demonstrated functional connectivity alterations in inter-hemispheric, frontal, occipital, default-mode (DMN) and motor network (MN) circuits. Herein, we report our experience in a cohort of iNPH patients that underwent cerebrospinal fluid (CSF) dynamics evaluation and rs-fMRI. The study aimed to identify functional circuits related to iNPH and explore the relationship between DMN and MN recordings and clinical modifications before and after infusion and tap test, trying to understand iNPH pathophysiology and to predict the best responders to ventriculoperitoneal shunt (VPS) implant. METHODS: We prospectively collected data regarding clinical assessment, neuroradiological findings, lumbar infusion and tap test of thirty-two iNPH patients who underwent VPS implant. Rs-fMRI was performed using MELODIC-ICA both before and after the tap test. Rs-fMRI data of thirty healthy subjects were also recorded. RESULTS: At the baseline, reduced z-DMN and z-MN scores were recorded in the iNPH cohort compared with controls. Higher z-scores were recorded in more impaired patients. Both z-scores significantly improved after the tap test except in subjects with a low resistance to outflow value and without a significant clinical improvement after the test. A statistically significant difference in mean MN connectivity scores for tap test responders and non-responders was demonstrated both before (p = 0.0236) and after the test (p = 0.00137). A statistically significant main effect of the tap test on DMN connectivity after CSF subtraction was recorded (p = 0.038). CONCLUSIONS: Our results suggest the presence of a partially reversible plasticity functional mechanism in DMN and MN. Low values compensate for the initial stages of the disease, while higher values of z-DMN were recorded in older patients with a longer duration of symptoms, suggesting an exhausted plasticity compensation. The standardization of this technique could play a role as a non-invasive biomarker in iNPH disease, suggesting the right time for surgery. Trial Registration Prot. IRB 090/2021.

Primary Leptomeningeal Medulloblastoma in Adults: A Diagnostic Challenge-Case Report and Systematic Review.

Primary leptomeningeal medulloblastoma (PL-MB) in adults is a rare disease with a severe prognosis. A 35-year-old woman presented with headaches, diplopia, and gait ataxia, with triventricular hydrocephalus and descent of the cerebellar tonsils beyond the foramen magnum. Endoscopic third ventriculostomy was performed. Six months later, headaches recurred. Dilatation of the supratentorial ventricular system and massive cerebellar swelling without contrast-enhancing nodularities were reported. Occipitocervical decompression with duraplasty was performed. A bioptic diagnosis of PL-MB was made. Craniospinal irradiation and chemotherapy were administered. After 18 months, no recurrence was observed. Few cases of PL-MB have been reported: patients die before treatment or within a few days after surgery. Our long-term survival could be ascribable to a slow clinical presentation and an early diagnosis that allowed surgical treatment and the administration of a combined chemoradiotherapy protocol. Cerebellar swelling, even without associated enhancing lesions, with or without hydrocephalus, should be a neuroradiological alarm sign, and PL-MB should be considered.

Image-guided LINAC radiosurgery in hypothalamic hamartomas.

Introduction: Hypothalamic hamartomas (HH) are developmental malformations that are associated with mild to severe drug-refractory epilepsy. Stereotactic radiosurgery (SRS) is an emerging non-invasive option for the treatment of small and medium-sized HH, providing good seizure outcomes without neurological complications. Here, we report our experience treating HH with frameless LINAC SRS. Materials and methods: We retrospectively collected clinical and neuroradiological data of ten subjects with HH-related epilepsy that underwent frameless image-guided SRS. Results: All patients underwent single-fraction SRS using a mean prescribed dose of 16.27 Gy (range 16-18 Gy). The median prescription isodose was 79% (range 65-81 Gy). The mean target volume was 0.64 cc (range 0.26-1.16 cc). Eight patients experienced complete or near complete seizure freedom (Engel class I and II). Five patients achieved complete seizure control within 4 to 18 months after the treatment. Four patients achieved Engel class II outcome, with stable results. One patient had a reduction of seizure burden superior to 50% (Engel class III). One patient had no benefit at all (Engel class IV) and refused further treatments. Overall, at the last follow-up, three patients experience class I, five class II, one class III and one class IV outcome. No neurological complications were reported. Conclusions: Frameless LINAC SRS provides good seizure and long-term neuropsychosocial outcome, without the risks of neurological complications inherently associated with microsurgical resection.

Long-Standing Overt Ventriculomegaly in Adults (LOVA): Diagnostic Aspects, CSF Dynamics with Lumbar Infusion Test and Treatment Options in a Consecutive Series with Long-Term Follow-Up.

BACKGROUND: Long-standing overt ventriculomegaly in adults is a chronic form of hydrocephalus without a clear pathophysiological description and a consensus about the treatment. We present the results of endoscopic third ventriculostomy (ETV) in a consecutive series with a mean follow-up of 79 ± 23 months, highlighting how the preoperative lumbar infusion test could facilitate understanding the pathophysiology of the disease. METHODS: We retrospectively collected data regarding clinical assessment, neuroradiological findings, and preoperative lumbar infusion tests in 22 symptomatic patients. RESULTS: In the majority of cases, patients reported imbalance and gait disorders, and 8 subjects had headaches. The preoperative lumbar infusion test demonstrated a mean opening pressure of 13.95 ± 2.88 mm Hg, with plateau values ranging from 22 to 39 mm Hg. The resistance to outflow was 11.21 ± 2.00 mm Hg/mL/min. After the procedure, all patients reported improvement or halted progression in their presenting symptoms, whereas no significant reduction was demonstrated in Evans' index. One subject underwent a second ETV procedure after more than 2 years because of the failure of the endoscopic approach. CONCLUSIONS: A progressive exhaustion of brain compliance plays an important role in explaining the dichotomy between severe ventriculomegaly and mild clinical symptoms in patients with long-standing overt ventriculomegaly in adults. The role of the aqueductal stenosis as a diagnostic criterion might be reconsidered. The preoperative infusion test data support this observation. Preoperative assessment should include not only clinical and neuroradiological evaluation but also the study of cerebrospinal fluid dynamics. ETV should be considered the treatment of choice because of its safety and efficacy. Long-term follow-up is mandatory.

Late-onset occlusion of the Monro foramina after endoscopic third ventriculostomy in adults: Case discussion and review of the literature.

BACKGROUND: Few cases of adult idiopathic occlusion of the foramen of Monro (AIOFM) are described in the literature. The diagnosis of AIOFM after an endoscopic procedure is even more infrequent. CASE DESCRIPTION: We described the case of a 50-year-old woman who developed bilateral membranous occlusion of both Monro foramina 20 years after an endoscopic third ventriculostomy (ETV) for triventricular hydrocephalus due to an aqueductal stenosis. The patient underwent an endoscopic treatment (left foraminoplasty and septostomy) to check the patency of the stoma on the floor of the third ventricle. After the endoscopic procedure, the symptoms improved and the postoperative magnetic resonance imaging (MRI) demonstrated the resolution of the biventricular hydrocephalus. CONCLUSION: Bilateral occlusion of both FM with consequent bilateral lateral ventricles enlargement is an extremely rare condition, especially if we consider the cases of biventricular hydrocephalus after endoscopic procedures. In our opinion, an endoscopic approach should be attempted as first choice procedure, avoiding any intraventricular stent or shunt placement.

Computer-Guided In-House Cranioplasty: Establishing a Novel Standard for Cranial Reconstruction and Proposal of an Updated Protocol.

BACKGROUND: Restoring the ideal geometry of the skull vault can be a challenging task. This is especially true for complex cases when cranial reconstruction is associated with concomitant cranial resection in a one-stage procedure. Oftentimes, cranioplasty designing and production are delegated to external companies, with a significant increase in time and cost to fabricate an alloplastic implant. This case series collects and critically examines previous experiences in the field of in-house cranial reconstruction providing an updated protocol to establish a novel standard for cranial reconstruction with a substantial reduction of costs. MATERIALS AND METHODS: A virtual craniotomy was digitally designed by the surgeon and transferred in the operating room using navigation and a surgical guide. Cranial reconstruction was planned using interpolation functions, recreating the ideal shape of the skull vault. Molds were designed, and 3D printed to intra-operatively shape polymethyl methacrylate (PMMA) according to the pre-operative plan. For validating the accuracy of reconstruction, as well as the restoration of the appropriate skull thickness, software-encoded color maps and root-mean-square error (RMSE), were calculated. RESULTS: All surgeries were uneventful. No adverse reactions to PMMA were observed. Accuracy of the procedure was validated, showing a submillimetric deviation from the original planning and a plate thickness value similar to the adjoining bone. All steps of design and production were performed by the surgical team, and costs were seven to ten times less than the past. CONCLUSION: We discussed and improved previous reports in the field of computer-guided in-house cranioplasty, particularly when complex one-stage resective and reconstructive procedures are planned. The use of three-dimensional analyses provides a validation of the accuracy of the resulting cranial reconstruction. The authors hope that the results might inspire other colleagues to consider computer-guided in-house cranioplasty, giving surgeons the mastery of each planning phase with a substantial decrease in costs.

Combining Clinical and Molecular Data to Predict the Benefits of Carmustine Wafers in Newly Diagnosed High-Grade Gliomas.

PURPOSE OF REVIEW: The purpose of this study was to retrospectively evaluate the use of carmustine wafers (CWs) in the management of high-grade gliomas (HGGs). The data from our monoinstitutional series was compared with studies reported in the literature. Special emphasis was placed on the evaluation of side effects and the analysis of extent of resection and molecular profile as risk factors. RECENT FINDINGS: The implantation of CWs into the resection cavity during HGG treatment to deliver localized chemotherapy, followed by the Stupp protocol, remains debated in a clinical setting, largely due to the lack of appropriate phase III studies. Given the high expense and poorly characterized side effects associated with CW treatment, identification of patients most likely to benefit from this therapy could be clinically relevant. CWs may represent an effective and safe first-line treatment for patients with HGG that exhibit complete tumor resection and harboring a methylated MGMT promoter. Our investigation showed a much larger group of patients exhibiting long-term survival (> = 36 months), strongly supporting a potential survival benefit conferred via CW treatment. The pre-surgical definition of the MGMT promoter status could be of clinical use in identifying "good responders" to CW implantation.