Utility of diffusion tensor imaging and generalized q-sampling imaging for predicting short-term clinical effect of deep brain stimulation in Parkinson's disease.

PURPOSE: To assess whether diffusion tensor imaging (DTI) and generalized q-sampling imaging (GQI) metrics could preoperatively predict the clinical outcome of deep brain stimulation (DBS) in patients with Parkinson's disease (PD). METHODS: In this single-center retrospective study, from September 2021 to March 2023, preoperative DTI and GQI examinations of 44 patients who underwent DBS surgery, were analyzed. To evaluate motor functions, the Unified Parkinson's Disease Rating Scale (UPDRS) during on- and off-medication and Parkinson's Disease Questionnaire-39 (PDQ-39) scales were used before and three months after DBS surgery. The study population was divided into two groups according to the improvement rate of scales: ≥ 50% and < 50%. Five target regions, reported to be affected in PD, were investigated. The parameters having statistically significant difference were subjected to a receiver operating characteristic (ROC) analysis. RESULTS: Quantitative anisotropy (qa) values from globus pallidus externus, globus pallidus internus (qa_Gpi), and substantia nigra exhibited significant distributional difference between groups in terms of the improvement rate of UPDRS-3 scale during on-medication (p = 0.003, p = 0.0003, and p = 0.0008, respectively). In ROC analysis, the best parameter in predicting DBS response included qa_Gpi with a cut-off value of 0.01370 achieved an area under the ROC curve, accuracy, sensitivity, and specificity of 0.810, 73%, 62.5%, and 85%, respectively. Optimal cut-off values of ≥ 0.01864 and ≤ 0.01162 yielded a sensitivity and specificity of 100%, respectively. CONCLUSION: The imaging parameters acquired from GQI, particularly qa_Gpi, may have the ability to non-invasively predict the clinical outcome of DBS surgery.

Medium and Long-Term Data from a Series of 96 Endoscopic Transsphenoidal Surgeries for Cushing Disease.

OBJECTIVE: Postoperative data on Cushing's disease (CD) are equivocal in the literature. These discrepancies may be attributed to different series with different criteria for remission and variable follow-up durations. Additional data from experienced centers may address these discrepancies. In this study, we present the results obtained from 96 endoscopic transsphenoidal surgeries (ETSSs) for CD conducted in a well-experienced center. METHODS: Pre- and postoperative data of 96 ETSS in 87 patients with CD were included. All cases were handled by the same neurosurgical team between 2014 and 2022. We obtained data on remission status 3-6 months postoperatively (medium-term) and during the latest follow-up (long-term). Additionally, magnetic resonance imaging (MRI) and pathology results were obtained for each case. RESULTS: The mean follow-up duration was 39.5±3.2 months. Medium and long-term remission rates were 77% and 82%, respectively. When only first-time operations were considered, the medium- and long-term remission rates were 78% and 82%, respectively. The recurrence rate in this series was 2.5%. Patients who showed remission between 3-6 months had higher longterm remission rates than did those without initial remission. Tumors >2 cm and extended tumor invasion of the cavernous sinus (Knosp 4) were associated with lower postoperative remission rates. CONCLUSION: Adenoma size and the presence/absence of cavernous sinus invasion on preopera-tive MRI may predict long-term postoperative remission. A tumor size of 2 cm may be a supporting criterion for predicting remission in Knosp 4 tumors. Further studies with larger patient populations are necessary to support this finding.

Microsurgical anatomy of the isthmic cingulum: a new white matter crossroad and neurosurgical implications in the posteromedial interhemispheric approaches and the glioma invasion patterns.

ABTRACT: The dichotomy of the cingulum bundle into the dorsal supracallosal and ventral parahippocampal parts is widely accepted; however, the retrosplenial component with its multiple alternative connections has not been revealed. The aim of this study was to delineate the microsurgical anatomy of a connectionally transition zone, the isthmic cingulum, in relation to the posteromedial interhemispheric access to the atrium and discuss the relevant patterns of glioma invasion on the basis of its fiber connections. White matter (WM) fibers were dissected layer by layer in a medial-to-lateral, lateral-to-medial, and posterior-to-anterior fashion. All related tracts and their connections were generated using deterministic tractography. The magnetic resonance imaging (MRI) tractography findings were correlated with those of fiber dissection. A medial parieto-occipital approach to reach the atrium was performed with special emphasis on the cingulate isthmus and underlying WM connections. The isthmic cingulum, introduced as a retrosplenial connectional crossroad for the first time, displayed multiple connections to the splenium and the superior thalamic radiations. Another new finding was the demonstration of lateral hemispheric extension of the isthmic cingulum fibers through the base of the posterior part of the precuneus at the base of the parieto-occipital sulcus. The laterally crossing cingulum fibers were interconnected with three distinct association tracts: the middle longitudinal (MdLF), the inferior frontooccipital fasciculi (IFOF), and the claustro-cortical fibers (CCF). In the process of entry to the atrium during posterior interhemispheric approaches, the splenial and thalamic connections, as well as the laterally crossing fibers of the isthmic cingulum, were all in jeopardy. The connectional anatomy of the retrosplenial area is much more complicated than previously known. The isthmic cingulum connections may explain the concept of interhemispheric and medial to lateral cerebral hemisphere invasion patterns in medial parieto-occipital and posteromesial temporal gliomas. The isthmic cingulum is of key importance in posteromedial interhemispheric approaches to both: the atrium and the posterior mesial temporal lobe.

Comparison of Electrophysiological and Radiological Subthalamic Nucleus Length and Volume.

AIM: To investigate the surgical value of MER recordings and improve surgical technique by demonstrating the consistency between preoperative radiological STN volume and intraoperative neurophysiological STN length. MATERIAL AND METHODS: Sixty-one patients with PD were enrolled. The volumes of the STN were measured using magnetic resonance images 3-dimensional volume reconstructions of stereotactic magnetic resonance images. MER were performed in all patient and the maximal electrophysiologic length of the STN was recorded each patient. In the postoperative period, the permanent electrode was modeled and reconstructed in 3D, and the longest distance traveled in the STN was calculated. RESULTS: A total of 61 patients who underwent surgery between 2012-2022 were included in the study. Thirty-six (59%) of the patients were male, and 25 (41%) were female. A total of 122 STNs were performed with 166 electrodes. The most common end alignment used was center with 86. STN length averaged 4.9 mm (0-10.5 mm). The mean STN volume was 0.11 cm3. The STN Volume of men were significantly higher than women. The STN Length, Volume, and the target MER length showed a positive correlation significantly. CONCLUSION: With radiological advances, it is possible to better visualize the target points and define the boundaries better, and direct methods can be used more in making targeting plans. MER records obtained during surgery and STN dimensions in presurgical planning show compatibility, and it is seen that there may be differences between the right and left sides because of brain shifting. Although radiology is increasingly providing better support, electrophysiological recordings provides real-time information on the electrodes? locations and give the opportunity to surgical team choosing alternative target.

Relation Between ILAE Hippocampal Sclerosis Classification and Clinical Findings in Temporal Lobe Epilepsy.

AIM: To investigate the relationship between clinical features and prognosis of the hippocampal sclerosis (HS) cases and International League Against Epilepsy (ILAE) histopathology classification. MATERIAL AND METHODS: A hundred patients with refractory epilepsy who were operated with the diagnosis of the Mesial Temporal Lobe Epilepsy were included in the study. Socio-demographic characteristics, clinical and family histories, post-operative ILAE and Engel epilepsy scores and diagnostic tests were recorded. At the same time, all of the pathological specimens were classified according to the new semi-quantitative ILAE classification. A significant statistical relationship was investigated between clinical data and HS-ILAE groups. RESULTS: There were 36 male 64 female patients. The mean follow-up period was 6.5 years. 75% of the cases were HS-ILAE type 1, 19% HS-ILAE type 2, 6% were unidentifiable. FCD3A was detected in 3 patients. The HS-ILAE Type 2 ratio was high on the rightsided cases. In addition, HS-ILAE Type 1 ratio was high in patients with early seizure onset and long duration of epilepsy. There was no significant relationship between long-term ILAE and Engel epilepsy outcome scores and HS-ILAE types. CONCLUSION: Resection of mesiotemporal structures in hippocampal sclerosis provides seizure control in at least two-thirds of cases. Histopathological findings may help us understand the epileptogenicity-prognosis of HS. The relationship between ILAE histopathology classification and clinical factors will become more obvious in the future. According to our study, there was a relationship between onset age of epilepsy, epilepsy duration, lesion side and HS-ILAE types. The reinforcement of these relationships with larger series will benefit clinicians.