Temporal Stem Research Articles

Lateral Temporal Approach for Image-Guided Stereotactic Biopsy of Pineal Region Tumors

Biopsy of pineal region neoplasms is frequently accomplished by way of endoscopic transventricular access or using an image-guided, computer-assisted stereotactic approach. We evaluated a nonorthogonal lateral temporal approach for stereotactic biopsy of pineal region tumors as a variation of previously described stereotactic methods. Magnetic resonance imaging-guided frameless stereotaxy was used to plan and perform biopsies of pineal region tumors using a nonorthogonal trajectory extending from the superior or middle temporal gyri through the temporal stem, anterior to the atrium of the lateral ventricle, and posterior to the corticospinal tract. All patients had an uncomplicated postoperative course and remained at neurologic baseline. No parenchymal or ventricular hemorrhage was present on postoperative scans. A tissue diagnosis was obtained in all patients. This method appears to be a safe alternative to stereotactic biopsy using other trajectories and provides adequate tissue for definitive diagnosis.

Failed Hemispherotomy: Insights from Our Early Experience in 40 Patients

To study the factors responsible for failure of hemispherotomy and outcomes of revision surgery. The effect of the surgeon's learning curve on failures was also analyzed. Forty consecutive patients, who underwent functional hemispherotomy through a 4-year period, from the inception of the single-surgeon epilepsy surgery program, were analyzed. A total of 47 functional hemispherotomies were performed in the study period in 40 patients (7 revision surgeries on 6 patients). Mean age of the cohort was 9.45 ± 14.84 years and it included 7 infants (<2 years). Of the 9 patients (23.5%) who failed the first procedure, 6 qualified for revision surgery, all of whom belonged to the cohort of the first 15 patients treated during the first 2 years of the program. Hemimegalencephaly was the most common disease (n= 4). Ipsilateral temporal stem (n= 3), frontobasal connections (n= 2), splenium of corpus callosum (n= 2), and posterior insula (n= 2) were residual undisconnected substrates identified for revision on imaging. The substrates for failure were obvious in 5/6 patients and resulted from incomplete disconnection, implying surgical inadequacy. At the mean follow-up of 30± 13.17 months (range, 13-55 months), 35 of 40 patients (87.5%) remained seizure free (Engel class Ia), including 4/6 patients who underwent redo surgery. Revision did not benefit the remaining 2 patients (Engel class III). There was no mortality. Surgical revision is more common in hemimegalencephaly and in the early days of a surgical program. Affirmative neuroimaging improves the outcomes of subsequent revision surgery.

Naegleria Fowleri Diagnosed with Hospital Autopsy in a Toddler: A Case Study

Abstract Casestudy Naegleria fowleri, an amoeba, is typically found in warm freshwater lakes, ponds, rivers and hot springs. It is responsible for causing the incredibly rare and lethal central nervous system infection called Primary Amoebic Meningoencephalitis (PAM). In the United States, 145 confirmed cases have been documented since 1962. Most cases are associated with freshwater lakes, ponds and reservoirs, while only a handful have been linked to artificial recreational venues such as pools, interactive water play-grounds, and spas. In addition to highlighting a rare amoebic disease, this case illustrates the continued importance of hospital autopsies especially given recent ruling to eliminate the autopsy requirement by the Centers for Medicare and Medicaid Services. Results An otherwise healthy toddler had upper respiratory symptoms and otitis media days after returning from an artificial recreational water venue, becoming increasingly lethargic and febrile over the next few days. At the hospital, cerebrospinal fluid (CSF) abnormalities were suggestive but not consistent with bacterial meningitis. A meningoencephalitis panel, a Computed Tomograph (CT) scan of the head, and chest-x-ray were negative for abnormalities. Appropriate antimicrobial therapy was initiated. Three days after hospital admission, his symptoms worsened including development of dysconjugate gaze and signs of cerebellitis. He became increasingly hemodynamically unstable, suffered an arrest, and passed away days later. Conclusion Since this death did not fall under the state’s statutes mandating medicolegal autopsy, a hospital- requested autopsy was performed. Cerebral edema and a light gray to light green exudate was along the inferior and lateral left temporal lobe, brain stem, and cerebellum. An exuberant lymphoplasmacytic infiltrate with scattered polymorphonuclear leukocytes expanded the meninges. Small histiocyte-like cells with distinct eccentric nuclei and granular, vacuolated cytoplasm, confirmed by Centers for Disease Control and Prevention (CDC) to be Naegleria fowleri, were best visualized in the Virchow-Robin spaces and deeper parenchyma.

Cardiovascular risk factors and APOE‐ε4 status affect memory functioning in aging via changes to temporal stem diffusion

Prior research investigating associations between hypertension, obesity, and apolipoprotein (APOE) genotype status with memory performance among older adults has yielded inconsistent results. This may reflect, in part, a lack of first accounting for the effects these variables have on structural brain changes, that in turn contribute to age-related memory impairment. The current study sought to clarify the relationships between these factors via path modeling. We hypothesized that higher body mass index (BMI), hypertension, and being an APOE-ε4 allele carrier would predict poorer memory scores, with much of these effects accounted for by indirect effects operating via differences in the integrity of temporal stem white matter. Participants included 125 healthy older adults who underwent neuropsychological assessment and diffusion-weighted MRI scanning. Direct effects were found for hypertension and demographic variables including age, sex, and education. Importantly, indirect effects were found for BMI, hypertension, APOE-ε4 status, age, and sex, where these factors predicted memory scores via their impact on temporal stem diffusion measures. There was also a dual effect of sex, with a direct effect indicating that females had better memory performance overall, and an indirect effect indicating that females with greater temporal stem diffusion had poorer memory performance. Results suggest that changes to the integrity of temporal white matter in aging may underpin reduced memory performance. These results highlight that accounting for variables that not only directly impact cognition, but also for those that indirectly impact cognition via structural brain changes, is crucial for understanding the impact of risk factors on cognition.

Realistic head-shaped phantom with brain-mimicking metabolites for 7 T spectroscopy and spectroscopic imaging.

PurposeMoving to ultra‐high fields (≥7 T), the inhomogeneity of both RF (B 1) and static (B 0) magnetic fields increases, which further motivates us to design a realistic head‐shaped phantom, especially for spectroscopic imaging. Such phantoms provide images similar to the human brain and serve as a reliable tool for developing and examining methods in MRI. This study aims to develop and characterize a realistic head‐shaped phantom filled with brain‐mimicking metabolites for MRS and magnetic resonance spectroscopic imaging in a 7 T MRI scanner.MethodsA 3D head‐shaped container with three sections—mimicking brain, muscle and precranial lipid—was constructed. The phantom was designed to provide robustness to heating, mechanical damage and leakage, with easy refilling. The head’s shape and the agarose mixture were optimized to provide B 0 and B 1 distributions and T 1/T 2 relaxation values similar to those of human brain. Eight brain‐tissue‐mimicking metabolites were included for spectroscopy. The phantom was evaluated for localized spectroscopy, fast spectroscopic imaging and fat suppression.ResultsThe B 0 and B 1 maps showed distribution similar to that of human brain, with increased B 0 inhomogeneity near the nasal and ear areas and reduced B 1 in the temporal lobe and brain stem regions, as expected in vivo. The metabolites’ concentrations were verified by single‐voxel spectroscopy, showing an average deviation of 11%. Fast spectroscopic imaging and imaging with fat suppression were demonstrated.ConclusionA 3D head‐shaped phantom for human brain imaging and spectroscopic imaging in 7 T MRI was demonstrated, making it a realistic phantom for methodology development at 7 T.

Acute Viral Encephalitis Neuroimaging Spectrum

Acute viral encephalitis involves inflammation of the brain caused by multiple different viruses, with CT of the head and MR imaging of the brain involved in the initial diagnostic work-up. Although viral encephalitis may have nonspecific findings on neuroimaging, some imaging patterns have been identified in viral subtypes on MR imaging. The most common cause of encephalitis is herpes simplex virus, with the typical imaging features demonstrating unilateral medial temporal lobe signal abnormalities. Bilateral temporal lobe, cerebellum, and brain stem signal abnormalities are seen in herpes simplex virus 2, with associated edema, necrosis, and hemorrhage. Signal abnormalities are commonly seen in the bilateral basal ganglia, thalami, and mesial temporal lobes in West Nile virus encephalitis. HIV encephalitis is associated with symmetric signal abnormality in the periventricular and deep white matter, which can be differentiated from progressive multifocal leukoencephalopathy by asymmetric U-fiber involvement. The purpose of this article is to present imaging findings associated with typical and atypical cases of viral encephalitis to guide diagnosis, promote early intervention, and improve clinical outcomes.Learning Objective: Identify unique radiologic findings associated with different types of viral encephalitis to guide diagnosis and improve clinical outcomes.

3.0 Tesla MRI scanner evaluation of supratentorial major white matter tracts and central core anatomical structures of postmortem human brain hemispheres fixed by Klingler method

Background: As an advanced imaging technique for the human brain, the importance of magnetic resonance imaging technique (MRI) is indisputable. The study aims to contribute to the literature by imaging post-mortem human brain hemispheres fixed with the Klinger method through the a 3.0 Tesla MRI Scanner and by defining the supratentorial major white matter tracts and central core anatomical structures. Methods: In our study, 10 post-mortem human brain hemisphere specimens were placed in 10% formalin solution for at least two months according to the Klingler method. The images were obtained using a 3.0 Tesla MRI Scanner. Anatomical structures were described on the T1-T2 axial, coronal, and sagittal MRI sections and compared with control images obtained from healthy humans. Results: Our examination revealed major association fibers, the basal cores and nuclei were denser, and the connections between them were clearly visible. The basal nuclei particularly were visualized more clearly compared with the normal MRI examinations. The claustrum, putamen, lateral and medial part of globus pallidus, and the caudolenticular bridges of the caudate nucleus could be clearly distinguished. The optic radiation line toward the occipital area as well as the forceps major and minor were distinct in the axial sections. Meanwhile, the imaging emphasized the importance of temporal stem, and the fibers it contained were clearly observed in the coronal sections. Conclusion: The use of hemispheres fixed using the Klinger method in post-mortem MRI examinations on brain hemispheres showed a clear separation of white matter fibers and nuclear structures.

Seizure and neuropsychological outcomes in a large series of selective amygdalohippocampectomies with a minimally invasive subtemporal approach.

Debate continues over proper surgical treatment for mesial temporal lobe epilepsy (MTLE). Few large comprehensive studies exist that have examined outcomes for the subtemporal selective amygdalohippocampectomy (sSAH) approach. This study describes a minimally invasive technique for sSAH and examines seizure and neuropsychological outcomes in a large series of patients who underwent sSAH for MTLE. Data for 152 patients (94 women, 61.8%; 58 men, 38.2%) who underwent sSAH performed by a single surgeon were retrospectively reviewed. The sSAH technique involves a small, minimally invasive opening and preserves the anterolateral temporal lobe and the temporal stem. All patients in the study had at least 1 year of follow-up (mean [SD] 4.52 [2.57] years), of whom 57.9% (88/152) had Engel class I seizure outcomes. Of the patients with at least 2 years of follow-up (mean [SD] 5.2 [2.36] years), 56.5% (70/124) had Engel class I seizure outcomes. Preoperative and postoperative neuropsychological test results indicated no significant change in intelligence, verbal comprehension, perceptual reasoning, attention and processing, cognitive flexibility, visuospatial memory, or mood. There was a significant change in word retrieval regardless of the side of surgery and a significant change in verbal memory in patients who underwent dominant-side resection (p < 0.05). Complication rates were low, with a 1.3% (2/152) permanent morbidity rate and 0.0% mortality rate. This study reports a large series of patients who have undergone sSAH, with a comprehensive presentation of a minimally invasive technique. The sSAH approach described in this study appears to be a safe, effective, minimally invasive technique for the treatment of MTLE.

Temporopolar amygdalohippocampectomy: seizure control and postoperative outcomes.

The objective of this study was to evaluate the efficacy and safety of a modified surgical approach for the treatment of temporal lobe epilepsy secondary to hippocampal sclerosis (HS). This modified approach, called temporopolar amygdalohippocampectomy (TP-AH), includes a transsylvian resection of the temporal pole and subsequent amygdalohippocampectomy utilizing the limen insula as an anatomical landmark. A total of 61 patients who were diagnosed with HS and underwent TP-AH between 2013 and 2017 were enrolled. Patients performed pre- and postoperative diffusion tensor imaging and were classified according to Engel's scale for seizure control. To evaluate the functional preservation of the temporal stem white-matter fiber tracts, the authors analyzed postoperative Humphrey perimetries and pre- and postoperative neurocognitive performance (Rey Auditory Verbal Learning Test [RAVLT], Weschler Memory Scale-Revised [WMS-R], intelligence quotient [IQ], Boston Naming Test [BNT], and semantic and phonemic fluency). Demographic data and surgical complications were also recorded and described. After a median follow-up of 36 ± 16 months, 46 patients (75.4%) achieved Engel class I, of whom 37 (60.6%) were Engel class IA. No significant changes in either the inferior frontooccipital fasciculus and optic radiation tractography were observed postoperatively for both left- and right-side surgeries. Reliable perimetry was obtained in 40 patients (65.6%), of whom 27 (67.5%) did not present any visual field defects (VFDs) attributable to surgery, while 12 patients (30%) presented with quadrant VFD, and 1 patient (2.5%) presented with hemifield VFD. Despite a significant decline in verbal memory (p = 0.007 for WMS-R, p = 0.02 for RAVLT recognition), there were significant improvements in both IQ (p < 0.001) and visual memory (p = 0.007). Semantic and phonemic fluency, and scores on the BNT, did not change postoperatively. TP-AH provided seizure control similar to historical temporal lobe approaches, with a tendency to preserve the temporal stem and a satisfactory incidence of VFD. Despite a significant decline in verbal memory, there were significant improvements in both IQ and visual memory, along with preservation of executive function. This approach can be considered a natural evolution of the selective transsylvian approach.

The Caudate Nucleus: Its Connections, Surgical Implications, and Related Complications

The caudate nucleus is a C-shaped structure that is located in the center of the brain and is divided into 3 parts: the head, body, and tail. We detail the anatomic connections, relationships with other basal ganglia structures, and clinical implications of injury to the caudate nucleus. Anatomically, the most inferior transcapsular gray matter is the lentiform peduncle, which is the connection between the lentiform nucleus and caudate nucleus as well as the amygdala. The border between the tail and body of the caudate nucleus is the posterior insular point. The tail of the caudate nucleus is extraependymal in some parts and intraependymal in some parts of the roof of the temporal horn of the lateral ventricle. The tail of the caudate nucleus crosses the inferior limiting sulcus (temporal stem), and section of the tail during approaches to lesions involving the temporal stem may cause motor apraxia. The mean distance from the temporal limen point, which is the junction of the limen insula and inferior limiting sulcus, to the tail of the caudate nucleus in the temporal stem is 15.87 ± 3.10 mm. Understanding of the functional anatomy and connections of the distinct parts of the caudate nucleus is essential for deciding the extent of resection of lesions involving the caudate nucleus and the types of deficits that may be found postoperatively.

Temporal lobe structural evaluation after transsylvian selective amygdalohippocampectomy.

Mesial temporal lobe epilepsy (MTLE) is the most common type of focal epilepsy in adolescents and adults, and in 65% of cases, it is related to hippocampal sclerosis (HS). Selective surgical approaches to the treatment of MTLE have as their main goal resection of the amygdala and hippocampus with minimal damage to the neocortex, temporal stem, and optic radiations (ORs). The object of this study was to evaluate late postoperative imaging findings on the temporal lobe from a structural point of view. The authors conducted a retrospective evaluation of all patients with refractory MTLE who had undergone transsylvian selective amygdalohippocampectomy (SAH) in the period from 2002 to 2015. A surgical group was compared to a control group (i.e., adults with refractory MTLE with an indication for surgical treatment of epilepsy but who did not undergo the surgical procedure). The inferior frontooccipital fasciculus (IFOF), uncinate fasciculus (UF), and ORs were evaluated on diffusion tensor imaging analysis. The temporal pole neocortex was evaluated using T2 relaxometry. For the IFOF and UF, there was a decrease in anisotropy, voxels, and fibers in the surgical group compared with those in the control group (p < 0.001). An increase in relaxometry time in the surgical group compared to that in the control group (p < 0.001) was documented, suggesting gliosis and neuronal loss in the temporal pole. SAH techniques do not seem to totally preserve the temporal stem or even spare the neocortex of the temporal pole. Therefore, although the transsylvian approaches have been considered to be anatomically selective, there is evidence that the temporal pole neocortex suffers structural damage and potentially functional damage with these approaches.

Abstract WP368: Evaluation of Brain Regional Characteristics Related With Post-Stroke Delirium Using Machine Learning and Statistical Analysis

Background: The present study was performed to evaluate the brain regional characteristics related with development of post-stroke delirium using the machine learning and statistical analysis. Method: We used clinical and radiological data prospectively collected from 675 acute ischemic stroke patients, who were admitted in stroke unit from August 2017 to July 2018. Delirium occurrence in the patients was screened with Confusion Assessment Method and finally diagnosed using the criteria of the Diagnostic and Statistical Manual of Mental Disorders (fifth edition). Three machine learning models, Support Vector Machine (SVM), Random Forest (RF) and Tree-based Gradient Boosting (XGBoost), were applied for the prediction of post-stroke delirium with the clinical and radiologic data. And logistic regression analysis was performed to evaluate the significance of the brain regional parameters included in the importance features which were obtained from the XGBoost result. Results: Post-stroke delirium occurred in 66 (9.8%) of the total patients. On the comparison of the test accuracy to predict delirium occurrence, RF (94%), XGBoost test (93%), and SVM (89%) showed similar prediction rates. Of the brain regional parameters included in the top 30 feature importance, right side cerebral hemisphere, non-lacunar infarction, severity of periventricular white matter changes, acute temporal lobe lesion, cerebellum, brain stem, and previous lesions developed on right side cerebral hemisphere, and in temporal or frontal lobe. Conclusion: The present study shows that the brain regional characteristics related with the post-stroke delirium are shown to be significant when controlling the other features using statistical analysis with machine learning. Even though we need more studies to validate the relationships between post-stroke delirium and brain regional characteristics, the present brain regional characteristics could provide significant evidences to predict post-stroke delirium for the acute ischemic stroke patients.

ACT-22 CLINICAL RESULT AND CONSIDERATION OF 70 CASES OF INSULAR GLIOMA

Our policy for insular glioma has achieved more than 90% removal. The policy influence grade 2 to postpone farther treatment and grade 3 to extend prognosis. In this study, we analyzed our clinical data to be sure how this policy effect to insular glioma. First-onset tumor since 2006 to 2015 were collected and following parameters were analyzed retrospectively, such as the tumor, extension, surgical removal rate, complications, pathological and genomic diagnosis. Of all 70 cases, the average age was 41 years old (24–76). The pathological diagnosis and number of patients were DAmt 20, DAwt 1, AAmt 8, AAwt 5, AO 5, O 18. PFS of each pathological grade(2,3,4) were 55,5m, 42,6m and 4,7m, OS were nr, nr, 32,8 months. 57 cases of IDHmt showed 60,2m of PFS and n.r of OS. 10 cases of IDHwt showed 19,9m PFS and 35,8m OS. The average and median removal rate were 91.4% and 95%. The number of complication case were mild 9 and moderate 2 at 3 months after surgery. The invasion pattern from temporal stem showed that frontal base invasion cases was resulted as poor prognosis comparing with temporal or parietal extension. Number of patients with IDHwt, Oligodedroglial tumor and GBM were relatively low. Surgical complications are mainly caused in the first half of the proficiency process, 15% had paralysis due to LSA infarction. Most of grade 2 cases were treated without post-operative treatment and the prognosis was almost same as grade 3 cases which were treated by chemo and radiation therapy such as 55m, 43m of PFS and n.r of OS. AA wt and GBM showed almost same OS of 32m.We have reconsidered a new classification based on temporal stem extension from surgical point of view. Insular glioma is somewhat different from the other location glioma.

Enhancing outcomes of endoscopic vertical approach hemispherotomy: understanding the role of "temporal stem" residual connections causing recurrence of seizures.

The authors sought to analyze the residual connections formed by the temporal stem as a cause for seizure recurrence following endoscopic vertical interhemispheric hemispherotomy and to review and compare lateral approach (perisylvian) with vertical approach surgical techniques to highlight the anatomical factors responsible for residual connections. This study was a retrospective analysis of patients who underwent endoscopic hemispherotomy for drug-resistant epilepsy. Postoperative MR images were analyzed. Specific attention was given to anatomical 3D-acquired thin-section T1 images to assess the extent of disconnection, which was confirmed with a diffusion tensor imaging sequence. Cadaver brain dissection was done to analyze the anatomical factors responsible for persistent connections. Of 39 patients who underwent surgery, 80% (31/39) were seizure free (follow-up of 23.61 ± 8.25 months) following the first surgery. Thirty patients underwent postoperative MRI studies, which revealed persistent connections in 14 patients (11 temporal stem only; 3 temporal stem + amygdala + splenium). Eight of these 14 patients had persistent seizures. In 4 of these 8 patients, investigations revealed good concordance with the affected hemisphere, and repeat endoscopic disconnection of the residual connection was performed. Two of the 8 patients were lost to follow-up, and 2 had bihemispheric seizure onset. The 4 patients who underwent repeat endoscopic disconnection had seizure-free outcomes following the second surgery, increasing the good outcome total among all patients to 90% (35/39). Cadaveric brain dissection analysis revealed the anatomical factors responsible for the persistence of residual connections. In endoscopic vertical approach interhemispheric hemispherotomy (and also vertical approach parasagittal hemispherotomy) the temporal stem, which lies deep and parallel to the plane of disconnection, is prone to be missed, which might lead to persistent or recurrent seizures. The recognition of this limitation can lead to improved seizure outcome. The amygdala and splenium are areas less commonly prone to be missed during surgery.

Wandering in the City: Time, Memory, and Experience in Digital Game Space

Wandering in the City: Time, Memory, and Experience in Digital Game Space

Magnetic resonance fingerprinting of temporal lobe white matter in mesial temporal lobe epilepsy.

ObjectiveMesial temporal lobe epilepsy (MTLE) is a network disorder. We aimed to quantify the white matter alterations in the temporal lobe of MTLE patients with hippocampal sclerosis (MTLE‐HS) by using magnetic resonance fingerprinting (MRF), a novel imaging technique, which allows simultaneous measurements of multiple parameters with a single acquisition.MethodsWe consecutively recruited 27 unilateral MTLE‐HS patients and 22 healthy controls. Measurements including T1, T2, and PD values in the temporopolar white matter and temporal stem were recorded and analyzed.ResultsWe found increased T2 value in both sides, and increased T1 value in the ipsilateral temporopolar white matter of MTLE‐HS patients, as compared with healthy controls. The T1 and T2 values were higher in the ipsilateral than the contralateral side. In the temporal stem, increased T1 and T2 values in the ipsilateral side of the MTLE‐HS patients were also observed. Only increased T2 values were observed in the contralateral temporal stem. No significant differences in PD values were observed in either the temporopolar white matter or temporal stem of the MTLE‐HS patients. Correlation analysis revealed that T1 and T2 values in the ipsilateral temporopolar white matter were negatively correlated with the age at epilepsy onset.InterpretationBy using MRF, we were able to assess the alterations of T1 and T2 in the temporal lobe white matter of MTLE‐HS patients. MRF could be a promising imaging technique in identifying mild changes in MTLE patients, which might optimize the pre‐surgical evaluation and therapeutic interventions in these patients.

Microsurgical anatomy of the sagittal stratum.

The sagittal stratum (SS) is a critical neural crossroad traversed by several white matter tracts that connect multiple areas of the ipsilateral hemisphere. Scant information about the anatomical organization of this structure is available in literature. The goal of this study was to provide a detailed anatomical description of the SS and to discuss the functional implications of the findings when a surgical approach through this structure is planned. Five formalin-fixed human brains were dissected under the operating microscope by using the fiber dissection technique originally described by Ludwig and Klingler. The SS is a polygonal crossroad of associational fibers situated deep on the lateral surface of the hemisphere, medial to the arcuate/superior longitudinal fascicle complex, and laterally to the tapetal fibers of the atrium. It is organized in three layers: a superficial layer formed by the middle and inferior longitudinal fascicles, a middle layer corresponding to the inferior fronto-occipital fascicle, and a deep layer formed by the optic radiation, intermingled with fibers of the anterior commissure. It originates posteroinferiorly to the inferior limiting sulcus of the insula, contiguous with the fibers of the temporal stem, and ends into the posterior temporo-occipito-parietal cortex. The white matter fiber dissection reveals the tridimensional architecture of the SS and the relationship between its fibers. A detailed understanding of the anatomy of the SS is essential to decrease the operative risks when a surgical approach within this area is undertaken.

Inferior Fronto-Occipital fascicle anatomy in brain tumor surgeries: From anatomy lab to surgical theater

The Inferior Fronto-Occipital fascicle (IFOF) is a multitasking white matter (WM) bundle bridging frontal, temporal, parietal and occipital lobe. Many papers describe its role in the physiology of language, attention and affective behavior but its anatomical components and cortical terminations remain unclear.We analyze the surgical anatomy of the IFOF in the light of our experience with awake surgery, anatomical dissection on 10 human adult hemispheres (Klingler method) and literature review.Dissecting the specimens from lateral to medial we can describe 3 segments: a vertical segment that runs along the frontal lobe; an horizontal segment that runs along frontal lobe; an horizontal segment that runs from the limen insulae, passes into to the temporal stem and arrives at the parietal and occipital lobes. We retrospectively analyzed also 23 awake surgeries. 2 responses were elicited at subcortical stimulation at the third segment of the IFOF; stimulation gave paraphasias on the first segment of the IFOF in one case. All IFOF responses were founded in the left hemisphere.Anatomical knowledge is the cornerstone of surgical orientation, it allows eloquent structures to be reached quickly and it is of primary importance in awake surgery to avoid patient fatigue with lack of concentration.

Temporal Glioblastoma Mimicking Basal Ganglia Invasion: Distinguishing Removable and Unremovable Tumors

Maximal safe resection prolongs the survival of patients with glioblastoma (GB). However, whether total resection of the enhanced lesion is pursued or abandoned depends on preoperative judgments based on the findings of magnetic resonance imaging (MRI). Anatomically, medial temporal tumor tends to invade toward the temporal stem, insula, and basal ganglia, representing tumor with high surgical risk. In the present study, we describe the key radiologic features of medial temporal GB to achieve extent of resection. We reviewed all GB cases located in the temporal lobe (tGB) treated between April 2013 and March 2018 at Kitasato University Hospital. On the basis of MRI, tGB was simply classified into 3 groups: medial tGB and nonmedial tGB, and medial tGB was further subdivided into invading type and mimicking type. We focused on the resectability of medial tGB. Twenty-seven patients with tGB were identified. Twenty were included in the nonmedial tGB, and 7 were in the medial tGB. All medial tGB seemed to invade into the basal ganglia and/or the lenticulostriate arteries, but detailed examination revealed 2 types of tumor, invading type (3 cases) and mimicking type (4 cases). The invading type had true involvement of the basal ganglia and/or lenticulostriate arteries, whereas the mimicking type had no involvement of these structures. This new classification is highly effective, as the former is unresectable, but the latter is totally resectable. Medial tGB is a challenging tumor for maximal safe resection, so our classification will help to identify cases of removable medial tGB.

Functional connectivity of the raphe nucleus as a predictor of the response to selective serotonin reuptake inhibitors in obsessive-compulsive disorder.

Selective serotonin reuptake inhibitors (SSRIs) are first-line pharmacological agents for treating obsessive-compulsive disorder (OCD). However, because nearly half of patients show insufficient SSRI responses, serotonergic dysfunction in heterogeneous OCD patients should be investigated for precision medicine. We aimed to determine whether functional connectivity (FC) of the raphe nucleus (RN), the major source of most serotonergic neurons, was altered in OCD patients and could predict the SSRI response. A total of 102 medication-free OCD patients and 101 matched healthy control (HC) subjects participated in resting-state functional magnetic resonance imaging. Among them, 54 OCD patients were treated with SSRIs for 16 weeks, resulting in 26 responders and 28 nonresponders. Seed-based whole brain FC with the RN as a seed region was compared between the OCD and HC groups, as well as between SSRI responders and nonresponders. FC cluster values showing significant group differences were used to investigate factors correlated with symptomatic severity before treatment and predictive of SSRI response. Compared to HCs, OCD patients exhibited significantly larger FC between the RN and temporal cortices including the middle temporal gyrus (MTG), paracingulate gyrus, amygdala, hippocampus, putamen, thalamus, and brain stem. Greater RN-left MTG FC was positively correlated with OC symptom severity at baseline. In addition, larger FC of the RN-left MTG was also found in SSRI nonresponders compared to responders, which was a significant predictor of SSRI response after 16 weeks. The FC of RN may reflect the neurobiological underpinning of OCD and could aid future precision medicine as a differential brain-based biomarker.