A Real-World Experience of Rituximab: A Panacea in Therapy of Multiple Sclerosis in Low- and Middle-Income Setting.

BACKGROUND: Anti-CD20 monoclonal antibodies have received increasing attention in the past few years in the treatment of multiple sclerosis (MS). OBJECTIVES: This study describes the (i) efficacy and safety of rituximab in people living with MS and (ii) assesses clinical and imaging outcomes following rituximab in MS. METHOD: This is a chart review from the MS registry maintained at the institute from a University Hospital in South India. RESULT: Eighty-three (M:F, 26:57) people living with MS received rituximab as immunomodulation between 2007 and 2022 with a median follow-up duration of 18 months. Fifty-nine (71%) were classified as relapsing-remitting MS, 16 (19%) were secondary progressive MS, and 8 (10%) were primary progressive MS. Seventy-two (87%) MS patients did not experience any relapse after receiving rituximab. In relapsing-remitting MS patients, the mean annualized recurrence rate dropped from 1.24 ± 1.19 to 0.16 ± 0.37. Infusion-related reaction occurred in 5 (6% of adverse events), urinary infections in 7 (8.4%), systemic infections in 3 (3%), Pneumocystis carinii pneumonia occurred in 1 (1%), and herpes zoster infection in 1 (1%) patient. Mortality was observed in 3 (3.5%) patients. While being on rituximab, 18 (22%) patients had mild COVID-19 illness and they all made complete recovery without any sequalae. CONCLUSIONS: Rituximab is a safe, well-tolerated, easily accessible, inexpensive, and effective therapeutic option for people with MS. Rituximab showed both clinical and radiological improvement after a median follow-up of 1.5 years. None of our patients showed any severe COVID infection nor side effects after receiving COVID vaccination.

Computed tomography-guided frame-based stereotactic brain biopsy of non-enhancing lesions using indirect evidence of target selection, technical consideration, and early clinical experience.

Background: The objective was to study the effectiveness and diagnostic outcome of frame-based stereotactic brain biopsy (STB) done for contrast non-enhancing lesions using indirect evidence of target selection observed in a plain computed tomography (CT) scan of the head. Methods: Data of patients with contrast non-enhancing brain lesions who underwent STB are collected retrospectively from NIMHANS Bangalore, hospital neurosurgery database from January 2021 to March 2023. Those cases subjected to plain CT scans after fixing the stereotactic frame to the head were included in the study. A final histopathological report analysis of these cases was done to assess the diagnostic accuracy. Results: A total of 27 such cases were biopsied. The mean age of subjects was 44.04 ± 17.812 years. Most subjects were in the age group 31-40 years (29.6%). About 55.6% were male and 44.4% were female. The most common site of biopsy was the frontal lobe. The most common indirect evidence on CT was perilesional edema at 33.3% and periventricular location at 33.3%, followed by intralesional calcification at 11.1%. Our diagnostic accuracy was 92.59%. The asymptomatic hemorrhage rate was 2%, and an increase in perilesional edema was seen in 2% of cases. Conclusion: Indirect targeting is a safe and intuitive method for biopsy of contrast non-enhancing lesions. Due consideration is to be given to various findings visible in non-contrast CT scans of the head as indirect evidence of target selection while performing frame-based STB of contrast non-enhancing lesions. This method will also be helpful in resource-limited centers, especially in low-income countries.

Journey through ARSACS: Insights from a case series of seven patients - A single centre study and review of Indian cohort.

Background: In this study we describe the clinical, and investigations profile of 7 cases of autosomal-recessive spastic-ataxia of Charlevoix-Saguenay (ARSACS). Methods: We performed retrospective chart review of genetically proven cases of ARSACS from our database. Additionally, we reviewed literature for reported cases of ARSACS from India. Result: All seven patients had onset within the first-decade. As per the available data, all had walking difficulty (7/7), spastic-ataxia (7/7), classical neuroimaging findings (7/7), sensory-motor demyelinating polyneuropathy (6/6), abnormal evoked-potentials (5/5) and thickened retinal nerve fiber layer (3/3). Exome sequencing revealed 8 pathogenic/likely-pathogenic unique variants (6 novel) in SACS gene. Additional 21 cases (18 families) of ARSACS that could be identified from India had similar clinical and investigational findings. The most common c.8793delA variant may have a founder effect. Conclusion: Our series adds to the previously reported cases of ARSACS from India and expands the genetic spectrum by adding 6 novel variants.

Radiomics features for the discrimination of tuberculomas from high grade gliomas and metastasis: a multimodal study.

BACKGROUND: Tuberculomas are prevalent in developing countries and demonstrate variable signals on MRI resulting in the overlap of the conventional imaging phenotype with other entities including glioma and brain metastasis. An accurate MRI diagnosis is important for the early institution of anti-tubercular therapy, decreased patient morbidity, mortality, and prevents unnecessary neurosurgical excision. This study aims to assess the potential of radiomics features of regular contrast images including T1W, T2W, T2W FLAIR, T1W post contrast images, and ADC maps, to differentiate between tuberculomas, high-grade-gliomas and metastasis, the commonest intra parenchymal mass lesions encountered in the clinical practice. METHODS: This retrospective study includes 185 subjects. Images were resampled, co-registered, skull-stripped, and zscore-normalized. Automated lesion segmentation was performed followed by radiomics feature extraction, train-test split, and features reduction. All machine learning algorithms that natively support multiclass classification were trained and assessed on features extracted from individual modalities as well as combined modalities. Model explainability of the best performing model was calculated using the summary plot obtained by SHAP values. RESULTS: Extra tree classifier trained on the features from ADC maps was the best classifier for the discrimination of tuberculoma from high-grade-glioma and metastasis with AUC-score of 0.96, accuracy-score of 0.923, Brier-score of 0.23. CONCLUSION: This study demonstrates that radiomics features are effective in discriminating between tuberculoma, metastasis, and high-grade-glioma with notable accuracy and AUC scores. Features extracted from the ADC maps surfaced as the most robust predictors of the target variable.

The Clinical, Radiological and Genetic Spectrum of PLA2G6-Associated Neurodegeneration: An Experience From a Tertiary Center.

Background: Despite being the second most common type of neurodegeneration with brain iron accumulation, there is limited literature on PLA2G6-associated neurodegeneration (PLAN) within the Asian ethnicity, particularly in the Indian context. Methods: We conducted a retrospective observational study on patients with pathogenic/likely pathogenic PLA2G6 variants based on exome sequencing. Results: We identified 26 patients (22 families, 15 males) of genetically-confirmed PLAN with a median age of 22.5 years and age at onset of 13.0 years, encompassing various subtypes: infantile neuroaxonal dystrophy (5/26;19.2%), atypical neuroaxonal dystrophy (3/26;11.5%), dystonia-parkinsonism (5/26;19.2%), dystonia-parkinsonism-myoclonus (n = 4, 15.38%), early-onset Parkinson's disease (2/26;7.7%), complex dystonia (2/26;7.7%), and complicated hereditary spastic paraparesis (cHSP; 5/26;19.2%). The common initial symptoms included walking difficulty (7/26;26.9%), developmental regression (6/26;23.1%), and slowness (4/26;15.4%). Dystonia (14/26;53.8%), followed by parkinsonism (11/26; 42.3%), was the most common motor symptom. Non-motor symptoms included cognitive decline (12/26;46.2%) and behavioral changes (6/26;23.1%). Neuroimaging revealed cerebellar atrophy in 23/26 (88.5%) patients and claval hypertrophy in 80% (4/5) of INAD patients. Levodopa responsiveness was noted in 12 of 14 patients with parkinsonism/dystonia who received levodopa, and dyskinesia was noted in 10/11 patients. Genetic analysis revealed a total of 19 unique variants in PLA2G6 gene, of which 11 were novel. Twelve patients harbored the c.2222G>A variant, which is predominantly seen in Asian subpopulations. Conclusions: The study introduces 26 new patients of PLAN and 12 patients associated with the c.2222G>A variant, potentially forming the most extensive single center series to date. It also expands the phenotypic, neuroimaging, and genotypic spectrum of PLAN.

Prospective Study to Evaluate the Role of Dual Point Contrast-enhanced Magnetic Resonance Imaging in Differentiation of Brain Tumoral from Nontumoral Tissue: A Magnetic Resonance/PET Study.

Background and Purpose: Follow-up imaging of gliomas is crucial to look for residual or recurrence and to differentiate them from nontumoral tissue. Positron emission tomography (PET)-magnetic resonance imaging (MRI) is the problem-solving tool in such cases. We investigated the role of dual point contrast (DPC)-enhanced MRI to discriminate tumoral from the nontumoral tissue compared to PET-MRI taken as the gold standard. Materials and Methods: The institutional ethics committee approved the study, and consent was obtained from all the patients included in the study. We prospectively did immediate and 75-min delayed contrast MRI in glioma cases who came for follow-up as a part of PET-MRI study in our institute. Subtracted images were obtained using immediate and 75-min delayed contrast images. Color-coded subtracted images were compared with PET-MRI images. 75-min delayed contrast MRI and diffusion-weighted imaging (DWI) images with Gray Scale inversion were compared with PET attenuation-corrected images. Results: We included 23 PET MRI cases done with different radiotracers in our study. Overall, we found PET-DPC correlation in (20/20 ~ 100%) cases of enhancing tumors. In two cases (DOPA and fluorodeoxyglucose), since they were nonenhancing low-grade gliomas and the other one was melanoma with intrinsic T1 hyperintensity and the DPC technique could not be used. DWI-PET correlated in 17/19 (~89.4%) cases, and perfusion-weighted imaging (PWI)-PET dynamic susceptibility contrast (DSC)/ASL correlated in 14/18 (~77.7%) cases after cases with hemorrhage were excluded. Conclusion: DPC MRI showed a good correlation with PET MRI in discriminating tumoral from the nontumoral tissue. DPC MRI can act as a potential alternative to PET MRI in peripheral hospitals where PET is not available. However, the DPC technique is limited in low-grade nonenhancing gliomas.

Thalamic H3K27M altered diffuse midline gliomas: Clinicopathological and outcome analysis.

INTRODUCTION: Diffuse midline glioma (DMG) is a relatively new entity which was introduced in the fourth edition of the WHO classification of CNS tumours in 2016 and later underwent revision in 2021. It is an infiltrative glioma arising from midline structures, viz., thalamus, spine, and brainstem. Current literature on DMG is based majorly on brainstem lesions, and DMGs arising elsewhere remain unexplored. In our study, we have discussed our experience with thalamic DMGs. METHODOLOGY: This is a retrospective observational study of all patients with histopathologically proven DMG H3K27M altered, arising in the thalamus from 2018 to 2022. Clinical, neuroimaging, and pathology were re-reviewed, and prognostic factors for 3 months, 6 months, and overall survival (OS) were analyzed for all patients. RESULTS: There were 89 patients- 64 adults and 25 pediatric patients with thalamic DMG. The median age at presentation was 24 years. Raised ICP followed by limb weakness were the most common presenting complaints. Stereotactic biopsy was performed in 64 (71.9 %) patients and surgical decompression in 25 (28.1 %) patients. CSF diversion was required in 53 (59.6 %) patients. Median survival was 8 months in adults and 7 months in pediatric (p-value: 0.51). Raised ICP and TP53 mutation were prognostic factors in pediatric population. Radiotherapy with or without chemotherapy improved survival (p-value- <0.01). CONCLUSION: Thalamic DMGs have a poor prognosis which is comparable to brainstem DMGs. Radiotherapy improves survival in these patients. However, the disease remains an enigma and further work delving into its molecular characterization should be encouraged.

Probabilistic Tractography-Based Tremor Network Connectivity in Tremor Dominant Parkinson's Disease and Essential Tremor plus.

Background: The basal ganglia-thalamocortical (BGTC) and cerebello-thalamocortical (CTC) networks are implicated in tremor genesis; however, exact contributions across disorders have not been studied. Objective: Evaluate the structural connectivity of BGTC and CTC in tremor-dominant Parkinson's disease (TDPD) and essential tremor plus (ETP) with the aid of probabilistic tractography and graph theory analysis. Methods: Structural connectomes of the BGTC and CTC were generated by probabilistic tractography for TDPD (n = 25), ETP (ET with rest tremor, n = 25), and healthy control (HC, n = 22). The Brain Connectivity Toolbox was used for computing standard topological graph measures of segregation, integration, and centrality. Tremor severity was ascertained using the Fahn-Tolosa-Marin tremor rating scale (FTMRS). Results: There was no difference in total FTMRS scores. Compared with HC, TDPD had a lower global efficiency and characteristic path length. Abnormality in segregation, integration, and centrality of bilateral putamen, globus pallidus externa (GPe), and GP interna (GPi), with reduction of centrality of right caudate and cerebellar lobule 8, was observed. ETP showed reduction in segregation and integration of right GPe and GPi, ventrolateral posterior nucleus, and centrality of right putamen, compared with HC. Differences between TDPD and ETP were a reduction of strength of the right putamen, and lower clustering coefficient, local efficiency, and strength of the left GPi in TDPD. Conclusions: Contrary to expectations, TDPD and ETP may not be significantly different with regard to tremor pathogenesis, with definite overlaps. There may be fundamental similarities in network disruption across different tremor disorders with the same tremor activation patterns, along with disease-specific changes.

Dysregulated Cerebrospinal Fluid Proteome of Spinocerebellar Ataxia Type 2 and its Clinical Implications.

BACKGROUND: Abnormalities in ataxin-2 associated with spinocerebellar ataxia type 2 (SCA2) may lead to widespread disruptions in the proteome. This study was performed to identify dysregulated proteome in SCA2 and to explore its clinical-radiological correlations. METHODS: Cerebrospinal fluid (CSF) samples from 21 genetically confirmed SCA2 were subjected to shotgun proteome analysis using mass spectrometry (MS) and tandem mass tag (TMT)-based multiplexing. Proteins with at least 1.5-fold change in abundance were identified. Their relative abundance was measured using parallel reaction monitoring (PRM) and correlated against disease-related factors. RESULTS: Eleven proteins were significantly upregulated in SCA2. They belonged to the family of cell adhesion molecules and granins. Their fold changes showed significant clinical, genetic, and radiological correlations. CONCLUSIONS: Significant dysregulation of CSF proteome is seen in SCA2. The dysregulated protein may have potential use in clinical evaluation of patients with SCA2.

Safety and Efficacy of Biopsy in Patients with Diffuse Intrinsic Pontine Gliomas.

BACKGROUND: Diffuse intrinsic pontine gliomas are aggressive tumors that carry a poor prognosis with a 2-year survival rate of <10%. The imaging appearance is often pathognomonic, and surgical biopsy is not mandatory to initiate treatment in children. Studies of biopsy samples provide insight into the disease's molecular pathobiology and open prospects for targeted therapy. This study was conducted to determine the diagnostic yield and safety of stereotactic biopsies. METHODS: This is a prospective observational study from a single tertiary health care center. All patients with clinical and radiological features diagnostic of diffuse intrinsic pontine gliomas (DIPGs) who underwent biopsy from July 2018 to June 2023 were included. Biopsies were performed using either stereotactic frame-based, frameless, or endoscopic techniques. RESULTS: A total of 165 patients with DIPGs were evaluated in the study period. The option of biopsy with its associated risks and benefits was offered to all patients. A total of 76 biopsies were performed in 74 patients (40 children and 34 adults, including 2 repeat biopsies). The median age was 15 years. Diffuse midline gliomas, H3K27M altered, was the most common histopathological diagnosis (85% pediatric and 55.9% adults). The diagnostic efficacy of the procedure was 94.7%. The complication rate was 10.8%, with no permanent neurological deficits due to surgery. There was no procedure-related mortality. CONCLUSIONS: Establishing the safety of the procedure could be an important step toward popularizing the concept, which might offer a better understanding of the disease. Brainstem eloquence and a lack of direct benefit to patients are the primary obstacles to brainstem biopsy.

Introspection of UBNIN and Modified-UBNIN Algorithms for Structural MRI. Reply to Kelly et al. A Comparison of Brain-State Representations of Binary Neuroimaging Connectivity Data. Comment on "Samantaray et al. Unique Brain Network Identification Number for Parkinson's and Healthy Individuals Using Structural MRI. Brain Sci. 2023, 13, 1297".

The purpose of this reply is to address the comments given by Kelly et al. on our original paper "Unique Brain Network Identification Number for Parkinson's and Healthy Individuals using Structural MRI". We agree to the inadvertent rounding pitfall in our original paper due to the non-inclusion of symbolic math toolbox (MATLAB). We now provide the actual ranges (with decimal values) of the UBNIN values of healthy individuals and those with Parkinson's disease and further observations. Upon further introspection, we propose another variant, called Modified-UBNIN (UBNIN-MT,MN) which is highly weighted on the node with the highest network degree (i.e., connections). The italicized sentences within inverted commas are statements from Kelly et al.'s comment paper.

Standardization and Clinical Use of a Single-vial Formulation of Technetium-99m-Trodat Using Autoclave Method.

Background: Parkinson's disease (PD) is characterized by the degeneration of dopaminergic neurons in the substantia nigra. SPECT imaging using technetium-99m [99mTc] labeled trodat is the choice of imaging to differentiate PD from its other forms like drug-induced PD. Aims and Objectives: The main objective of our study was to prepare in-house sterile formulation of [99mTc]Tc-trodat and use in clinics. Materials and Methods: The labeling of trodat was standardized using glucoheptonate sodium salt (GHA), stannous chloride dihydrate (in 0.05 N HCl), and ethylenediaminetetraacetic acid (Na-EDTA). The preparation was mixed and autoclaved at 15 psi for 15 min. The standardised formulation was stored at 4°C, -20°C and -80°C and labeling with 99mTc was tested for up to 6 days. The radiochemical purity, chemical impurities, and endotoxin levels were tested. The frozen formulation was tested in swiss mice (n = 3) for biodistribution studies at 4 h. Around 18 ± 2 mCi was injected intravenously in each patient (n = 5) and the image was acquired at 4 h post-injection. Results: The radiochemical purity of the preparation was 98.3 ± 1.4% with a retention time of 16.8 ± 1.5 min as compared to 4.0 ± 0.5 min for free 99mTc. Animal distribution showed highest uptake in liver and dual excretion via hepatobiliary and renal system. [99mTc]Tc-trodat imaging was able to differentiate both caudate and putamen. Conclusions: In-house frozen preparation was advantageous, as it has decreased the chance of manual error as compared to daily make up formulations and economical as compared to commercially available kits.

Cardiac Rhythm Aberrations in Subacute Sclerosing Panencephalitis: Insights From Heart Rate Variability Analysis.

PURPOSE: Subacute sclerosing panencephalitis (SSPE) is a fatal neurological disorder resulting from persistent measles virus infection within the brain. Although neurological manifestations have been well-documented, the impact of SSPE on cardiac autonomic function, assessed through heart rate variability (HRV), remains understudied. METHODS: In this prospective single-center study conducted from January 2022 to March 2023 in Southern India, 30 consecutive SSPE patients and age- and sex-matched controls underwent electrocardiogram recordings for HRV analysis. Various HRV parameters were assessed, including time-domain metrics (SD of normal-to-normal intervals, root mean square of successive differences between normal heartbeats, percentage of successive normal interbeat intervals greater than 50 msec), SD1 and SD2 for Poincaré plot analysis, and frequency-domain metrics (low frequency %, high frequency %, low frequency:high frequency ratio). RESULTS: In the study, SSPE patients exhibited markedly reduced HRV. Specifically, SD of normal-to-normal intervals (P = 0.003), percentage of successive normal interbeat intervals greater than 50 msec (P = 0.03), and SD2 (P = 0.0016) were significantly lower compared with controls. Frequency-domain analysis did not reveal significant distinctions. Correlation analysis demonstrated a negative relationship between percentage of successive normal interbeat intervals greater than 50 msec and SSPE severity (r = -0.37, P = 0.042). Heart rate variability did not significantly differ between SSPE stages or with clinical variables. The interbeat interval range showed a narrower distribution in SSPE subjects. CONCLUSIONS: Our study highlights the clinical relevance of HRV analysis in SSPE and autonomic dysfunction throughout the disease course underscoring its importance in SSPE. This investigation provides valuable insights into cardiac autonomic dysfunction probably because of affliction of the central autonomic networks caused by the disease process and may be a contributing factor to mortality in SSPE.

Clinical and Imaging Profile of Patients with Cerebrotendinous Xanthomatosis - a Video Case Series from India.

Background: Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder caused by bi-allelic pathogenic variants in CYP27A1 gene that results in the deposition of cholestanol in the eyes, tendons, soft tissues and nervous system leading to cataracts, xanthomas, and various neuropsychiatric manifestations. The aim of our study is to describe the clinical, radiological and genetic profile of patients with CTX. Methods: This is a retrospective chart review of patients with CTX diagnosed based on classical clinical and radiological findings. The available clinical details, and investigations, including imaging, electrophysiological, pathological and genetic data, were documented. Results: Five patients (4 males) were recruited in the study. The median age at presentation was 32 years (range: 21-66 years). Walking difficulty was the most common symptom at presentation. All patients had cataracts, tendon xanthomas, eye movement abnormalities, dysarthria, pyramidal signs, ataxia and gait abnormality. Dystonia was noted in three patients. Palatal tremor and parkinsonism were noted in one patient each. In MRI brain, dentate, and corticospinal tract involvement were the most frequent imaging findings. Bilateral hypertrophic olivary degeneration was noted in one patient and hot cross bun sign in two. Three patients underwent genetic testing and all had pathogenic variants confirming the diagnosis. Discussion: CTX is a rare treatable disorder. Apart from the usual neurological presentation with spastic-ataxia, it can present at a later age with parkinsonism. Typical patterns of imaging findings are helpful in early diagnosis which aids in the treatment to prevent the neurological sequelae of the disease.

Role of Optical Coherence Tomography in Predicting Visual Outcome after Surgery for Sellar and Supra-Sellar Tumors.

BACKGROUND: Almost one-fifth of patients undergoing surgery for sellar/supra-sellar tumors do not gain a significant improvement in their vision. Various methods have been described to predict prospective visual outcomes in them, although they lack uniformity. OBJECTIVE: The study was conducted to predict visual outcomes following surgery for sellar and supra-sellar tumors compressing the anterior optic pathway based on pre-operative optical coherence tomography (OCT) parameters. METHODS AND MATERIALS: This was a record-based observational descriptive longitudinal study done in a tertiary care center in India. Thirty-seven patients (74 eyes) diagnosed with sellar supra-sellar lesions were included in the study. Patients' ophthalmic evaluations, done pre-operatively and 3 months post-operatively, were reviewed. Spectral-domain OCT and segmentation were done using the automated segmentation technology of Spectralis software. The thickness of the respective layers was measured. RESULTS AND CONCLUSIONS: The mean age of the study population was 42.68 years. Eyes with a pre-operative visual acuity component of VIS (visual impairment score) ≤61, pre-operative ganglion cell layer thickness ≥26.31 um, a pre-operative inner plexiform layer thickness of ≥25.69 um, a pre-operative ganglion cell inner plexiform layer thickness of 52.00 um, pre-operative ganglion cell complex thickness ≥84.47 µm, and a pre-operative inner retinal layer thickness of ≥205.25 µm were more likely to have an improved visual outcome. Eyes with a pre-operative duration of visual symptoms of ≥15 months, VIS ≥126.50, a pre-operative decimal visual acuity of <0.035, a pre-operative visual field index of ≤8%, a pre-operative macular thickness of ≤287.06 um, a pre-operative macular RNFL (retinal nerve fiber layer) thickness ≤66.00 µm, and a pre-operative peri-papillary RNFL thickness ≤64.62 µm were unlikely to have visual improvement.

Differential patterns of functional connectivity in tremor dominant Parkinson's disease and essential tremor plus.

Tremor dominant Parkinson's disease (TDPD) and essential tremor plus (ETP) syndrome are commonly encountered tremor dominant neurological disorders. Although the basal ganglia thalamocortical (BGTC) and cerebello thalamocortical (CTC) networks are implicated in tremorogenesis, the extent of functional connectivity alterations across disorders is uncertain. This study aims to evaluate functional connectivity of the BGTC and CTC in TDPD and ETP. Resting state functional MRI was acquired for 25 patients with TDPD, ETP and 22 healthy controls (HC). Following pre-processing and denoising, seed-to-voxel based connectivity was carried out at FDR < 0.05 using ROIs belonging to the BGTC and CTC. Fahn-Tolosa-Marin tremor rating scale (FTMRS) was correlated with the average connectivity values at FDR < 0.05. Compared to HC, TDPD showed decreased connectivity between cerebellum and pre, post central gyrus. While, ETP showed decreased connectivity between pallidum and occipital cortex, precuneus, cuneus compared to HC. In comparison to ETP, TDPD showed increased connectivity between precentral gyrus, pallidum, SNc with the default mode network (DMN), and decreased connectivity between cerebellum with superior, middle frontal gyrus was observed. Tremor severity positively correlated with connectivity between SNc and DMN in TDPD, and negatively correlated with pallidal connectivity in ETP. Pattern of BGTC, CTC involvement is differential i.e., higher connectivity of the BGTC nodes in TDPD, and higher connectivity of cerebellar nodes in ETP. The interesting observation of pallidal involvement in ETP suggests the role of BGTC in the pathogenesis of ETP, and indicated similarities in concepts of tremor genesis in TDPD and ETP.

Evaluating the Diagnostic Efficacy of 99mTc-Methionine Single-Photon Emission Computed Tomography-Computed Tomography: A Head-to-Head Comparison with 11C-Methionine Positron Emission Tomography-Magnetic Resonance Imaging in Glioma Patients.

Background: Amino acid positron emission tomography (PET) imaging plays a significant role in the diagnosis of gliomas and in differentiating tumor recurrence from necrosis. In this study, the authors evaluated the diagnostic efficacy of [99mTc]Tc-methionine single-photon emission computed tomography-computed tomography (SPECT-CT) in comparison with [11C]methionine PET-magnetic resonance imaging (MRI) in delineating tumors. Methods: Thirty-one (primary: 16 and postoperative: 15) patients of confirmed (either MRI or histopathological proven) glioma underwent both [99mTc]Tc-methionine SPECT-CT and [11C]methionine PET-MRI. A comparative analysis was performed between SPECT, PET, and MR images to calculate the concordance between the modalities and to evaluate the diagnostic efficacy of the [99mTc]Tc-methionine SPECT. Results: [99mTc]Tc-methionine SPECT showed comparable uptake in the tumor lesions in comparison to [11C]methionine PET. A significant and strong positive correlation was observed between the volume of tumor (Vt) in PET and Vt MR (p < 0.004). Likewise, a significant and strong positive correlation was found between Vt SPECT and Vt MR. [99mTc]-methionine has a sensitivity and specificity of 91% and 75%, respectively, compared with 82% and 100% for [11C]methionine in postoperative cases to differentiate the tumor recurrence from necrosis. The sensitivity and specificity of [99mTc]Tc-methionine was 92% and 100%, respectively, compared with 92% and 67% for [11C]methionine in primary tumors. Conclusion: [99mTc]Tc-methionine SPECT-CT is as equally good as [11C]methionine for diagnosing and differentiating it from necrosis especially in high-grade glioma.