Posterior Brainstem Research Articles

Extra-axial desmoplastic/nodular medulloblastoma in adult mimicking cerebellar metastasis: reappraisal of this rare presentation with literature review

Introduction and importance: Medulloblastomas are the most common malignant intra-axial brain tumour in paediatric patients and represent 35–40% of posterior fossa tumour types in children between 3 and 9 years of age. Medulloblastomas may also be found in adulthood. These tumours are classified into two groups according to its molecular characteristics and histological type. The desmoplastic/nodular subtype is the second common subtype after the classic one. Only three cases of desmoplastic/nodular extra-axial medelloblastoma have been previously reported in the literature originating from to the cerebellopontine angle. Case presentation: The authors report a new case of an extra-axial desmoplastic/nodular cerebellar medulloblastoma originating outside the cerebellopontine angle and mimicking a solitary cerebellar metastasis in a 49-year-old female patient who presented for a raised intracranial pressure and cerebellar syndrome. Clinical discussion: Medulloblastoma is a malignant embryonal intra-axial tumour of the cerebellum or posterior brain stem that occurs mainly in children. Medulloblastomas may also be found in adulthood. Desmoplastic/nodular medulloblastoma is the second most common type of all medulloblastomas. The intra-axial form is always predominant. Only three cases of extra-axial desmoplastic/nodular medulloblastoma have been reported in the literature. The authors will go through the literature to dissect this rare entity. Conclusion: Although considered a common paediatric intra-axial tumour, there are increasing numbers of solitary cases reporting an extra-axial presentation in different locations of the posterior cerebral fossa even in adulthood. These rare and unusual presentations and locations may mislead the correct diagnosis and delay treatment.

Blood Brain Barrier is functional 24 hours following Pregnancy related Acute Kidney Renal Injury

From 1999 to 2011, incidences of pregnancy related acute kidney injury (PR-AKI) increased from 2.4 to 6.3 per every 10,0000 deliveries in the U.S. Acute Kidney Injury (AKI) is associated with increased circulating uremic toxins such as indoxyl sulfate (I.S) and p cresyl sulfate (PCS), cognitive dysfunction and blood brain barrier (BBB) disruption. The purpose of these experiments was to determine if 24 hours following AKI there is evidence of BBB dysfunction in a model of PR-AKI. We hypothesized that AKI would lead to BBB disruption while the treatment of I.S alone does not as our overall hypothesis is that accumulation of uremic toxins following renal injury leads to cognitive dysfunction. Time-pregnant Sprague Dawley rats arrived on gestational day (GD)10 and were randomized into the following groups: normal pregnant (NP; n=5-9), AKI (n=5-8), 100 I.S (n=5-10), and 200 I.S (n=5-9). Beginning on GD11, a subset of rats received either 100 mg/kg body weight (BW) or 200 mg/kg BW dose of I.S via drinking water daily. On GD18, AKI rats received a 45-min bilateral renal ischemic reperfusion surgery. On GD19, blood pressure was taken via CODA tail cuff followed by organ and blood collection. Five animals per group were injected with 4% Evan’s Blue (EB) for 30 mins and flushed with saline. Residual EB was measured in the frontal and posterior cortices, brain stem, and cerebellum. Serum was used to measure I.S and PCS via mass spectrometry. Creatinine was measured in both urine and serum via assay (BioAssay Systems). Data was analyzed via one-way ANOVA followed by multiple comparisons via GraphPad Prism. Statistical significance was determined as p<0.05. AKI animals had a higher kidney weight/BW ratio to NP (p=0.04), 100 I.S (p=0.003), and 200 I.S (p=0.04) while 200 I.S had a larger kidney to BW ratio to NP rats (p=0.02). AKI had smaller spleen weight/BW(p=0.02) ratios compared to NP rats. Pups born to AKI dams were significantly smaller than NP (p=0.001), 100 I.S (p=0.01), and 200 I.S (p <0.0001) dams. 200 I.S (p=0.02) had an increase in placental efficiency (placenta weight/ pup weight) compared to NP rats. Circulating I.S is significantly decreased in 100 I.S rats compared to NP (p=0.04) and AKI (p=0.04). PCS was significantly increased in AKI rats compared to NP (p=0.02), 100 I.S (p=0.03), and 200 I.S (p=0.03). When EB was measured, 200 I.S had significantly more EB in the brain stem region (p=0.01) compared to AKI rats. A one-way ANOVA showed differences in creatinine levels between groups (p=0.04), but multiple comparisons showed no differences between specific groups. PR-AKI led to changes in kidney and spleen weight without differences in BW which could be contributed by the immune response of the injury. We have preliminary data showing increases in circulating I.S 4 months post-partum which suggests increases occur later in postpartum. The brain stem is an interest of study as it has been shown to be implicated in chronic renal failure. Funding to AG (William Townsend Porter Predoctoral Fellowship from American Physiological Society), to KW (Chan Zuckerberg Initiative Science Diversity Leadership Award) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Atypical Clinical Presentations and Neuroimaging Findings of Wernicke Encephalopathy (P4-4.004)

<h3>Objective:</h3> Wernicke encephalopathy is an acute neurological disorder secondary to thiamine deficiency with a clinical triad of confusion, eye disorders, and ataxia. Typical MRI Findings show symmetric hyperintensities in T2-weighted sequences predominantly affecting medial thalami, periaqueductal area, mammillary body, and the tectal plate. We describe two atypical cases of Wernicke encephalopathy. <h3>Background:</h3> N/A <h3>Design/Methods:</h3> Retrospective chart review. <h3>Results:</h3> <h3>First Case:</h3> 50-year-old female with history of endometrial cancer presented with altered mental status (AMS), truncal ataxia, neck titubation, and incomplete external ophthalmoplegia, progressing rapidly to stupor. She had recently undergone chemoradiation, complicated by chronic radiation enteritis causing poor oral intake, recurrent emesis, and weight loss. After an extensive negative infectious workup, MRI Brain with contrast was performed, which revealed restricted diffusion and T2-FLAIR sequence hyperintensities of bilateral cerebella, bilateral dorsomedial thalami, fornix with contrast enhancement of mammillary bodies concerning for Wernicke Syndrome. Thiamine levels were confirmed to be 70 nmol/l. <h3>Second Case:</h3> 22-year-old female with history of Autism Spectrum Disorder presented with AMS and seizure-like activity after experiencing severe nausea and vomiting for one week. Infectious workup including CSF analysis was unremarkable. No seizures or epileptiform changes were captured on vEEG. MRI Brain showed T2 FLAIR hyperintensities with restricted diffusion throughout the posterior brainstem, bilateral thalami, caudate nuclei, left medial lentiform nucleus, bilateral periventricular basal ganglia, bilateral frontal and parietal lobes raising concerns for Wernicke encephalopathy. Serum thiamine level was less than 20, corroborating with the diagnosis. Both patients had significant clinical and radiographic improvement with high-dose thiamine supplementation. <h3>Conclusions:</h3> The classic triad of symptoms of Wernicke encephalopathy is usually present in only 16% of patients. Atypical MRI Brain findings include involvement of the cerebral cortex and cerebellum which are more commonly seen in non-alcoholic patients. Mortality rate ranges from 10–20% so prompt recognition of the condition and early treatment is vital especially in atypical cases. <b>Disclosure:</b> Dr. Biyani has nothing to disclose. Dr. Verma has nothing to disclose. Dr. Arulprakash has nothing to disclose. Dr. Shah has nothing to disclose. Dr. Patrice has nothing to disclose.

Prognostic value of pretreatment diffusion-weighted imaging score for acute basilar artery occlusion with successful endovascular recanalization.

The aim of this study is to test the prognostic value of a diffusion-weighted imaging (DWI) score in acute basilar artery occlusion (ABAO) with successful recanalization. The DWI-based pons-midbrain and thalamus (PMT) score was developed to assess posterior circulation infarcts. We test its prognostic value and compare it with other two established scales, the DWI-based posterior circulation acute stroke prognosis Early CT score (PC-ASPECTS) and brain stem score (BSS). A retrospective cohort of consecutive ABAO patients with pretreatment magnetic resonance imaging and successful recanalization (defined as modified Thrombolysis in Cerebral Infarction 2b-3) were analyzed. A favorable outcome was defined as a 90-day modified Rankin Scale (mRS) score of 2 or less. The prognostic performance of three scales was estimated by receiver operating characteristic (ROC) curve analyses. One hundred and sixteen eligible patients (mean age, 59.1 ± 11.7 [standard deviation]; 96 [82.8%] man) were included and evaluated. Between favorable (mRS ≤ 2) and unfavorable groups, the baseline PMT score (median [interquartile range], 3 [1-4] versus 6 [5-8]; P < 0.001) differs significantly. ROC curve analyses showed the PMT score had the best prognostic value for favorable outcome (area under the curve, PMT versus BSS versus PC-ASPECTS = 0.80 versus 0.72 versus 0.68, P = 0.010). Multivariate logistic regression analyses showed baseline National Institute of Health stroke scale (OR, 0.90 [95%CI, 0.86-0.95], P = 0.004) and PMT score < 5 (OR, 17.83 [95%CI, 3.91-81.19], P < 0.001) were independent prognostic factors of favorable outcome. The PMT score seems to predict clinical outcome of ABAO patients with successful recanalization.

Large-Scale Mapping of Vocalization-Related Activity in the Functionally Diverse Nuclei in Rat Posterior Brainstem.

The identity and location of vocalization pattern generating (VPG) circuits in mammals is debated. Based on physiological experiments, investigators suggested anterior brainstem circuits in the reticular formation, and anatomic evidence suggested the nucleus retroambiguus (NRA) in the posterior brainstem, or combinations of these sites as the putative mammalian VPG. Additionally, vocalization loudness is a critical factor in acoustic communication. However, many of the underlying neuronal mechanisms are still unknown. Here, we evoked calls by stimulation of the periaqueductal gray in anesthetized male rats, performed a large-scale mapping of vocalization-related activity using the activity marker c-fos, and high-density recordings of brainstem circuits using Neuropixels probes. Both c-fos expression and recording of vocalization-related activity point to a participation of the NRA in vocalization. More important, among our recorded structures, we found that the NRA is the only brainstem area showing a strong correlation between unit activity and call intensity. In addition, we observed functionally diverse patterns of vocalization-related activity in a set of regions around NRA. Dorsal to NRA, we observed activity specific to the beginning and end of vocalizations in the posterior level of the medullary reticular nucleus, dorsal part, whereas medial and lateral to the NRA, we observed activity related to call initiation. No clear vocalization-related activity was observed at anterior brainstem sites. Our findings suggest a set of functionally heterogeneous regions around the NRA contribute to vocal pattern generation in rats.SIGNIFICANCE STATEMENT Vocalization patterns are shaped in the mammalian brainstem, but the identity and location of the circuits involved is debated. Additionally, the neuronal mechanisms of vocal intensity control are still unknown. This study consisted of a large-scale mapping of brainstem vocalization circuits based on the activity marker c-fos and high-density recordings with Neuropixels probes. The results confirm the role of nucleus retroambiguus in call production and point to a key role of neurons in this nucleus in loudness control. Dorsal to the nucleus retroambiguus and in the posterior medulla, the authors identify neurons with activity specific to the beginning and end of vocalizations. The results point to specific neural dials for various aspects of rat vocalization control in the posterior brainstem.

FDG-PET findings and alcohol-responsive myoclonus in a patient with Unverricht-Lundborg disease.

The aim of this report is to describe clinical, EEG, and neuroimaging findings in a patient with Unverricht-Lundborg disease (ULD), the most common form of progressive myoclonus epilepsy (PME). A 23-year-old male with genetically confirmed ULD had a phenotype consisting of myoclonus, generalized seizures, intellectual disability, ataxia, and dysarthria. Myoclonus and gait disturbance were strongly ameliorated by alcohol consumption. EEG revealed a posterior dominant rhythm with alpha variant, mild bilateral slowing, and anterior-predominant epileptiform abnormalities. Brain MRI showed mild cerebellar atrophy. FDG-PET revealed hypometabolism more prominent in the posterior brainstem, thalami, frontal and parietal lobes. This report confirms that alcohol may ameliorate myoclonus in a subset of patients with PME, including genetically confirmed ULD. In addition, the presence of FDG-PET hypometabolism predominant in the frontoparietal region and thalami has not been previously described in ULD, yet is consistent with previous brain morphometry studies showing motor cortex and thalamic atrophy in ULD, and brings into question the possibility of a shared metabolic pattern with other PMEs, notably Lafora disease.

Novel Diffusion-Weighted Imaging Score Showed Good Prognostic Value for Acute Basilar Artery Occlusion Following Endovascular Treatment: The Pons-Midbrain and Thalamus Score.

Prognostic factors for outcome of endovascular treatment remains to be investigated in patients with acute basilar artery occlusion. We aimed to assess the prognostic value of a novel pretreatment diffusion-weighted imaging score: The Pons-Midbrain and Thalamus (PMT) score. Eligible patients who underwent endovascular treatment due to acute basilar artery occlusion were reviewed. The PMT score was a diffusion-weighted imaging-based semiquantitative scale in which the infarctions of pons, midbrain, and thalamus were fully considered. The PMT score was assessed as well as the posterior circulation Acute Stroke Prognosis Early Computed Tomography Score and Brain Stem Score. Good outcomes were defined as a modified Rankin Scale score of ≤3 at 90-day and successful reperfusion as Thrombolysis in Cerebral Infarction grades 2b/3. The associations between baseline clinical parameters and good outcomes were evaluated with logistic regression. A total of 107 patients with pretreatment magnetic resonance imaging were included in this cohort. The baseline PMT score (median [interquartile range], 3 [1-5] versus 7 [5-9]; P<0.001) and Brain Stem Score (median [interquartile range], 2 [1-4] versus 3 [2-5]; P=0.001) were significantly lower in good outcome group; the posterior circulation Acute Stroke Prognosis Early Computed Tomography Score was higher in good outcome group without statistical significance. As a result of receiver operating characteristic curve analyses, the posterior circulation Acute Stroke Prognosis Early Computed Tomography Score showed poor prognostic accuracy for good outcome (area under the curve, 0.60 [95% CI, 0.49-0.71]; P=0.081); The baseline PMT score showed significantly better prognostic accuracy for 90-day good outcome than the Brain Stem Score and National Institutes of Health Stroke Scale (area under the curve, 0.80 versus 0.68 versus 0.78, P=0.003). In addition, favorable PMT score <7 (odds ratio, 22.0 [95% CI, 6.0-80.8], P<0.001), Brain Stem Score <3 (odds ratio, 4.65 [95% CI, 2.05-10.55], P<0.001) and baseline National Institutes of Health Stroke Scale <23 (odds ratio, 8.0 [95% CI, 2.5-25.6], P<0.001) were associated with improved good outcome. In patients with acute basilar artery occlusion following endovascular treatment, the pretreatment diffusion-weighted imaging based PMT score showed good prognostic value for clinical outcome.

Cortical and subcortical hemodynamic changes during sleep slow waves in human light sleep

EEG slow waves, the hallmarks of NREM sleep are thought to be crucial for the regulation of several important processes, including learning, sensory disconnection and the removal of brain metabolic wastes. Animal research indicates that slow waves may involve complex interactions within and between cortical and subcortical structures. Conventional EEG in humans, however, has a low spatial resolution and is unable to accurately describe changes in the activity of subcortical and deep cortical structures. To overcome these limitations, here we took advantage of simultaneous EEG-fMRI recordings to map cortical and subcortical hemodynamic (BOLD) fluctuations time-locked to slow waves of light sleep. Recordings were performed in twenty healthy adults during an afternoon nap. Slow waves were associated with BOLD-signal increases in the posterior brainstem and in portions of thalamus and cerebellum characterized by preferential functional connectivity with limbic and somatomotor areas, respectively. At the cortical level, significant BOLD-signal decreases were instead found in several areas, including insula and somatomotor cortex. Specifically, a slow signal increase preceded slow-wave onset and was followed by a delayed, stronger signal decrease. Similar hemodynamic changes were found to occur at different delays across most cortical brain areas, mirroring the propagation of electrophysiological slow waves, from centro-frontal to inferior temporo-occipital cortices. Finally, we found that the amplitude of electrophysiological slow waves was positively related to the magnitude and inversely related to the delay of cortical and subcortical BOLD-signal changes. These regional patterns of brain activity are consistent with theoretical accounts of the functions of sleep slow waves.

Variability of Normal Pressure Hydrocephalus Imaging Biomarkers with Respect to Section Plane Angulation: How Wrong a Radiologist Can Be?

Systematic analysis of angulation-related variability of idiopathic normal pressure hydrocephalus imaging biomarkers has not been published yet. Our aim was to evaluate the variability of these radiologic biomarkers with respect to imaging plane angulation. Eighty subjects (35 with clinically confirmed idiopathic normal pressure hydrocephalus and 45 age- and sex-matched healthy controls) were prospectively enrolled in a 3T brain MR imaging study. Two independent readers assessed 12 radiologic idiopathic normal pressure hydrocephalus biomarkers on sections aligned parallel or perpendicular to the bicallosal, bicommissural, hypophysis-fastigium, and brain stem vertical lines, respectively. Disproportionately enlarged subarachnoid space hydrocephalus, simplified callosal angle, frontal horn diameter, z-Evans Index, and cella media vertical width did not show significant systematic differences in any of 6 section plane combinations studied. The remaining 7 biomarkers (including the Evans Index and callosal angle) showed significant differences in up to 4 of 6 mutually compared section plane combinations. The values obtained from sections aligned with the brain stem vertical line (parallel to the posterior brain stem margin) showed the most deviating results from other section angulations. Seven of 12 idiopathic normal pressure hydrocephalus biomarkers including the frequently used Evans Index and callosal angle showed statistically significant deviations when measured on sections whose angulations differed or did not comply with the proper section definition published in the original literature. Strict adherence to the methodology of idiopathic normal pressure hydrocephalus biomarker assessment is, therefore, essential to avoid an incorrect diagnosis. Increased radiologic and clinical attention should be paid to the biomarkers showing low angulation-related variability yet high specificity for idiopathic normal pressure hydrocephalus-related morphologic changes such as the z-Evans Index, frontal horn diameter, or disproportionately enlarged subarachnoid space hydrocephalus.

P0619 / #1524: ACUTE NECROTIZING ENCEPHALOPATHY (ANE) RELATED TO INFLUENZA AND MYCOPLASMA PNEUMONIAE IN A CHILD

Aims & Objectives: Background: ANE is a rare neurologic complication of influenza which lead to profound disability or death.The co-infection role of M. pneumoniae on this condition has not been previously reported. Aims: Clinical case presentation. Methods: Methodology: Chart review and literature search. Results: A previously healthy 5-year-old female, 3 hours before admission presents with fever, restlessness, and an involuntary bowel movement. She became confused and developed right hemiparesis and dysarthria. Soon after arrival to the ER, she developed right-sided clonic seizures, coma, bilateral areactive mydriasis with no corneal reflex, and hypotension. An admission brain-CT (Fig. 1)scan reported no intracranial abnormalities, but a MRI (Fig. 2), performed 2 hours after stabilization, reported diffuse hyperintensity with cytotoxic edema in cerebellar hemispheres, posterior brainstem, thalamus, basal ganglia, gray and white supra and infratentorial substance, findings consistent with ANE. Despite decompressive craniotomy and maximum therapeutic efforts, intracranial hypertension was severe and refractory to treatment. A PCR respiratory panel was positive for Influenza A/H1-2009, A/H1-pan, A/pan1, A/pan2 and M. pneumoniae. Blood and urine cultures were negative. A CT scan after 12 hours reported total obliteration of the CSF spaces, occipital transcranial herniation, and absence of intracranial circulation. The patient died after 36 hours. A post-mortem CSF analysis, including a PCR panel and culture, were negative.Conclusions: ANE is a consequence of an inappropriate immune response to virus and bacteria associated with poor outcomes or severe complications. More research is needed to stablish an association with a genetic predisposition.

A Functionally and Anatomically Bipartite Vocal Pattern Generator in the Rat Brain Stem.

SummaryThe mammalian vocal pattern generator is situated in the brainstem but its exact structure is debated. We mapped these circuits in rats by cooling and microstimulation. Local cooling disrupted call production above an anterior and a posterior brainstem position. Anterior cooling affected predominantly high-frequency calls, whereas posterior cooling affected low-frequency calls. Electrical microstimulation of the anterior part led to modulated high-frequency calls, whereas microstimulation of the posterior part led to flat, low-frequency calls. At intermediate positions cooling did not affect calls and stimulation did not elicit calls. The anterior region corresponds to a subsection of the parvicellular reticular formation that we term the vocalization parvicellular reticular formation (VoPaRt). The posterior vocalization sites coincide with the nucleus retroambiguus (NRA). VoPaRt and NRA neurons were very small and the VoPaRt was highly myelinated, suggestive of high-speed processing. Our data suggest an anatomically and functionally bipartite vocal pattern generator.

The Paramedian Supracerebellar Approach: A Less Disruptive and More Flexible Operative Corridor to the Pineal and Posterior Upper Brainstem Regions

The paramedian supracerebellar craniotomy is an underrecognized route to the midline and paramedian regions of the upper posterior brainstem. As compared with its midline supracerebellar counterpart, this less disruptive approach preserves the majority of the midline bridging veins, requires less cerebellar retraction, and is significantly more efficient. In this offering, I will emphasize the realities of this flexible route and its remarkable advantages in reaching deep-seated lesions.

Longitudinal Assessment of Neuroradiologic Features in Wolfram Syndrome.

Wolfram syndrome is a rare genetic disease with characteristic brain involvement. We reviewed the brain MR images of patients with Wolfram syndrome to determine the frequency and characteristics of common neuroradiologic findings. We retrospectively reviewed the imaging data of patients with genetically-confirmed Wolfram syndrome who had been recruited to the Washington University Wolfram Syndrome Research Clinic. These patients were evaluated between 2010 and 2019 with annual MRIs, along with other measures. MR images were assessed for clinical neuroradiologic signs at each individual's first and last follow-up visits to characterize the frequency, rate of progression, and clinical correlations of these signs. We included 30 patients (13 males/17 females; average age at first visit, 14 years; average age at last visit, 19 years). The median duration of follow-up was 5 years (range, 2-9 years). The most common findings were an absent or diminished posterior pituitary bright spot (first, 53%; last, 70%), T1/T2 pons signal abnormalities (first, 53%; last, 67%), optic nerve atrophy (first, 30%; last, 80%), white matter T2 hyperintensities (first, 27%; last, 35%), and cerebellar atrophy (first, 23%; last, 70%). Patients with Wolfram syndrome present characteristic neuroradiologic findings that involve the posterior pituitary gland, optic nerves, white matter, brain stem, and cerebellum. These abnormal findings appear at an early age and tend to increase in frequency with time. However, the neurologic significance and neuropathologic mechanisms of each sign require more investigation. Neuroradiologists should be aware of the pattern of these features in Wolfram syndrome.

Endoscopic third ventriculostomy for obstructive hydrocephalus.

To determine the success rate of endoscopic third ventriculostomy (ETV) for treating obstructive hydrocephalus. Cross-sectional observational study. The Neurosurgery Department of PGMI, Lady Reading Hospital, Peshawar, from May 2010 to November 2011. Patients with obstructive hydrocephalus due to aqueductal stenosis, tectal and non-tectal tumour and already shunted patients for obstructive hydrocephalus presented with blocked shunt were included in the study. Patients with congenital hydrocephalus and secondary to meningitis were excluded. Endoscopic third ventriculostomy was performed. Success, complications and mortality was noted. Data was analyzed by descriptive statistics using SPSS software version 17. There were 155 patients including 72 males and 83 females with ratio of 1: 1.33. Success rate was 71%. Indication of surgery was obstructive hydrocephalus due to aqueductal stenosis, posterior fossa tumour, brain stem and CP angle tumour. Complications were seen in 18 patients including mortality in 3 patients. ETV is effective, safe and successful procedure in patients with obstructive hydrocephalus. It may be used as replacement procedure of ventriculo-peritoneal shunt as initial line of management in selected patients.

Shape Deformation in the Brainstem of Medication-Naïve Female Patients with Major Depressive Disorder.

ObjectiveAlthough neuroimaging studies have shown volumetric reductions, such as the anterior cingulate, prefrontal cortices, and hippocampus in patients with major depressive disorder (MDD), few studies have investigated the volume of or shape alterations in the subcortical regions and the brainstem. We hypothesized that medication-naïve female adult patients with MDD might present with shape and volume alterations in the subcortical regions, including the brainstem, compared to healthy controls (HCs). MethodsA total of 20 medication-naïve female patients with MDD and 21 age-matched female HCs, underwent 3D T1-weighted structural magnetic resonance scanning. We analyzed the volumes of each subcortical region and each brainstem region, including the midbrain, pons, and medulla oblongata. We also performed surface-based vertex analyses on the subcortical areas and brainstem. ResultsFemale patients with MDD showed non-significant volumetric differences in the subcortical regions, whole brainstem, and each brainstem region compared to the HCs. However, in the surface-based vertex analyses, significant shape contractions were observed in both cerebellar peduncles located on the lateral wall of the posterior brainstem [threshold-free cluster enhancement, corrected for family-wise error (FWE) at p<0.05] in patients with MDD. ConclusionWe revealed shape alterations in the posterior brainstem in female patients with MDD.

Effect of various blood glucose levels on regional FDG uptake in the brain.

Objective(s):Studies have mainly assessed the effect of hyperglycemia on 18F-fluorodeoxyglucose (FDG) uptake in the brain. In this study, we assessed the FDG uptake of the brain not only in normo- and hyperglycemia but also in hypoglycemia to compare the effect of various blood glucose levels on regional FDG uptake in the brain.Methods:This retrospective study was conducted on whole-body FDG positron emission tomography/computed tomography (PET/CT) images including the brain. The inclusion criteria included adult patients with no known history of diseases or symptoms affecting the brain, lack of abnormal brain findings on both PET and CT images, no image artifacts, and lack of any factors affecting brain FDG uptake. Maximum standardized uptake values (SUVmax) were measured in the lateral and medial frontal, temporal, parietal, and occipital cortices, lateral cerebellar cortex, posterior cingulate cortex, caudate nucleus, putamen, thalamus, brain stem (BS), and scalp in patients with normal (91-100 mg/dl), low (61-70 mg/dl), and high (171-200 mg/dl) blood glucose (BG) levels. Mean SUVmax of the brain regions for each BG range was calculated and statistically analyzed.Results:In all BG levels, FDG uptake was at the highest level in the lateral frontal cortex and lowest level in the medial temporal cortex (MTC) and BS. The SUVmax in all assessed brain regions was significantly lower in hyperglycemia (P<0.001). However, this value was not significantly different in hypoglycemia (P>0.05) as compared to that in normoglycemia. At the BG range of 171-200 mg/dl, hyperglycemia-induced reduction in regional SUVmax had a range of 55.9-63.7% (60%±2.4%). This reduction was below 60% in the MTC, cerebellum, and BS and above 60% in other regions. Scalp activity was lower in hyperglycemia (P<0.001) and not different in hypoglycemia (P>0.05) as compared to normoglycemia.Conclusion:The FDG uptake appears to be at the highest level in the lateral frontal cortex and the lowest level in the MTC and BS in normo-, hypo-, and hyperglycemia. Hyperglycemia-induced reduction in FDG uptake was approximately the same as that in various regions of the brain. However, the MTC, cerebellum, and BS may be slightly less affected than the other regions. Hypoglycemia does not seem to have a significant effect on FDG uptake in the brain.

Reliability of MR Imaging-Based Posterior Fossa and Brain Stem Measurements in Open Spinal Dysraphism in the Era of Fetal Surgery.

Fetal MR imaging is part of the comprehensive prenatal assessment of fetuses with open spinal dysraphism. We aimed to assess the reliability of brain stem and posterior fossa measurements; use the reliable measurements to characterize fetuses with open spinal dysraphism versus what can be observed in healthy age-matched controls; and document changes in those within 1 week after prenatal repair. Retrospective evaluation of 349 MR imaging examinations took place, including 274 in controls and 52 in fetuses with open spinal dysraphism, of whom 23 underwent prenatal repair and had additional early postoperative MR images. We evaluated measurements of the brain stem and the posterior fossa and the ventricular width in all populations for their reliability and differences between the groups. The transverse cerebellar diameter, cerebellar herniation level, clivus-supraocciput angle, transverse diameter of the posterior fossa, posterior fossa area, and ventricular width showed an acceptable intra- and interobserver reliability (intraclass correlation coefficient > 0.5). In fetuses with open spinal dysraphism, these measurements were significantly different from those of healthy fetuses (all with P < .0001). Furthermore, they also changed significantly (P value range = .01 to < .0001) within 1 week after the fetal operation with an evolution toward normal, most evident for the clivus-supraocciput angle (65.9 ± 12.5°; 76.6 ± 10.9; P < .0001) and cerebellar herniation level (-9.9 ± 4.2 mm; -0.7 ± 5.2; P < .0001). In fetuses with open spinal dysraphism, brain stem measurements varied substantially between observers. However, measurements characterizing the posterior fossa could be reliably assessed and were significantly different from normal. Following a fetal operation, these deviations from normal values changed significantly within 1 week.

0217 Resistance to Sleep Deprivation is Predicted by Gray Matter Volume in the Posterior Brain Stem

0217 Resistance to Sleep Deprivation is Predicted by Gray Matter Volume in the Posterior Brain Stem

One burr-hole craniotomy: Suboccipital midline approach to the fourth ventricle in Helsinki neurosurgery.

Background:In this video-abstract, we present one burr-hole craniotomy for the standard suboccipital midline approach developed in Helsinki neurosurgery for the microsurgical management of forth ventricle lesions, distal posterior inferior cerebellar artery aneurysms, and tumoral and vascular lesions of the vermis, cisterna magna region, and posterior brainstem as well.Case Description:We prefer to position the patient in sitting praying position. A midline straight single-layer incision starts on the inion and extends caudally toward the level of C2. The muscles are divided with diathermia along the occipital bone. Three curved retractors, two upward and one downward, provide a wide clean space for the craniotomy. Finger palpation and blunt dissection with cottonoids balls provide identification of the foramen magnum and the spinous process of C1. A burr-hole is made 1 cm lateral and below the level of the transverse sinus. After the detachment of the dura with a curved angled dissector, two cuts from both sites of the burr-hole are made with the craniotome. In case of an adherent dura particularly present in elderly patients, a long blunt flexible dissector (yasargil dissector) is used for the detachment of the bone from the dura. A craniotomy around the midline overlying the occipital sinus and the falx cerebelli is performed to expose medial aspects of cerebellar tonsils, the medulla oblongata, and the occipital sinus. Special care should be taken to avoid damaging the vertebral artery and the epidural sinuses running at the foramen magnum. A few drill holes are made for tack-up sutures. After a craniocervical-based opening of the dura, the fourth ventricle is accessed directly by telovelar route.Conclusion:The described one burr-hole craniotomy may represent the more efficient manner for performing the suboccipital midline approach to the fourth ventricle.Videolink:http://surgicalneurologyint.com/videogallery/suboccipital-midline-approach/

Neuroradiological Features of Six Patients with Propionic Acidemia

AbstractPropionic acidemia (PA) is a rare autosomal recessive neurometabolic disorder caused by propionyl-CoA carboxylase deficiency. Diffuse brain atrophy, myelination delay, and basal ganglia abnormalities, either chronic or transient, have been previously reported in brain magnetic resonance imaging (MRI) of patients with PA. Clinical manifestations are heterogeneous and long-term outcome of affected individuals is unpredictable.Neuroradiological studies and clinical symptoms of six patients diagnosed with PA were reported in our center between 1999 and 2015. Brain MRI was performed in all patients (sagittal T1-weighted images, axial T2-weighted images, coronal FLAIR images, and axial diffusion-weighted images) and magnetic resonance spectroscopy (MRS) in four of them. Follow-up MRI abnormalities are heterogeneous and highly variable over time, in some cases even reversible. New neuroradiological findings are for the first time reported here as cerebellum signal changes, posterior brain stem diffusion restriction, and cortical development malformations. We suggest including serial MRI in follow-up programs as a monitoring tool in assessing intracerebral changes in PA, but more data are required to evaluate the benefits of serial MRI in PA patients.