Pituitary spindle cell oncocytoma: Two cases report and literature review.

INTRODUCTION: Pituitary spindle cell oncocytoma (PSCO) is a seldom-encountered type of pituitary neoplasm with distinctive histological features. It was first described as a distinct entity by Roncaroli et al. in 2002. We present two cases of PSCO and discuss its clinical, radiological, and histopathological features, along with a review of the existing literature. PRESENTATION OF CASE: Two cases underwent trans-nasal transsphenoidal surgery for tumor resection and had different treatment following would be discussed in this article. Both had unique pathology pattern as Pituitary spindle cell oncocytoma. DISCUSSION: Tumors positive for TTF-1 in the sellar region, such as pituicytoma, granular cell tumor, and spindle cell oncocytoma, originate from the posterior pituitary gland and are rare. The expression of thyroid transcription factor-1 (TTF-1) in these tumors aids in distinguishing them from other pituitary neoplasms. CONCLUSION: Pituitary spindle cell oncocytoma is a rare entity among pituitary tumors. This case report highlights the clinical, radiological, histopathological, and immunohistochemical features of PSCO. Surgeons and pathologists should consider this rare diagnosis in patients with sellar and suprasellar masses, as early recognition and complete surgical resection can lead to favorable outcomes.

Atypical venous drainage system and distinct vascular characteristics in pediatric intracerebral hemorrhage caused by multiple micro arteriovenous malformations.

BACKGROUND: Hemorrhagic brain micro-arteriovenous malformations (micro-AVMs) are considered to constitute a relatively significant portion of pediatric AVMs, though they are often associated with a low bleeding rate, as seen in hereditary hemorrhagic telangiectasia, which frequently involves multiple micro-AVMs. We present a rare case of a 10-year-old girl with multiple hemorrhagic micro-AVMs. Intraoperative findings during the emergency operation for hematoma evacuation and post-operative superselective angiography highlighted the unique angioarchitecture of three micro-AVMs (two lesions in the superficial areas and one lesion in the deep-seated area) and the atypical bleeding source due to the complex congestive venous drainage system. One micro-AVM was successfully occluded by a transarterial emboliozation, and remaining two micro-AVMs underwent gamma knife irradiation as a salvage therapy. CONCLUSION: Superselective angiography is crucial for detecting micro-AVMs, offering detailed insights into small, localized abnormal vascular drainage systems, and guiding therapeutic strategy. Additionally, micro-AVM-associated unique vascular hypersensitivity, such as vasospasm, requires careful consideration, as invasive procedures may significantly alter the visibility of the entire micro-AVM network.

How safe and effective is irradiating radiation-induced meningiomas? Single-center experience in primary and salvage Gamma-Knife Radiosurgery, systematic review, and metanalysis of current evidence on the topic.

This is a single-center experience and metanalysis of the safety and efficacy measures of Gamma-knife stereotactic radiosurgery (SRS-GK) for radiation-induced meningiomas (RIMs). This study comprised a single-center analysis of SRS-GK for RIMs at IRCCS San Raffaele Hospital, Milan, Italy, and a systematic literature review and meta-analysis to address the actuarial local control (LC), distant control (DC), progression-free survival (PFS), and toxicity. The original series comprised 13 patients harboring 30 RIMs. Partial response was observed in 26 %, stability in 52 %, and progression in 22 %. The 5-year LC and DC rates were 71 % and 67 %. One patient developed radionecrosis, and an additional 2 presented edema. Metanalysis comprised 4 papers and data from the original series, comprising 146 patients and 308 RIMs. The 5-year LC was 84 %, the DC 67 %, and radionecrosis in 1.4 %. SRS-GK has an efficacy profile falling between that observed for radiologically suspected sporadic meningiomas and confirmed higher-grade lesions.

Dosimetric comparison of gamma knife and linear accelerator (VMAT and IMRT) plans of SBRT of Lung tumours.

This study evaluates dosimetric differences in Stereotactic Body Radiation Therapy (SBRT) for lung tumors using plans of Gamma Knife, and Volumetric Modulated Arc Therapy (VMAT), Intensity-Modulated Radiation Therapy (IMRT) plans based on Linear Accelerator, aiming to inform the reader of appropriate treatment strategy selection. Ten patients with 23 lung tumor lesions treated with SBRT at Zhongshan Hospital of Dalian University were analyzed. Plans of Gamma Knife, and VMAT, IMRT plans based on Linear Accelerator were created for each lesion, totaling 18 plans per type. Lesions were treated with 30-50 Gy in 5-10 fractions. Dosimetric parameters, including gradient index (GI), heterogeneity index (HI), conformity index (CI), and doses to the plan target volumes (PTVs), the gross tumor volumes (GTVs) and organs at risk (OARs) were compared. Plans of Gamma Knife showed superior HI and GI, higher PTV and GTV doses, and reduced doses to the ipsilateral and contralateral lungs, esophagus, spinal cord, and heart compared to VMAT and IMRT plans (p < 0.05). However, Plans of Gamma Knife required longer delivery times. When comparing VMAT and IMRT plans, VMAT plans had shorter delivery times than IMRT plans, but required more monitor units (MUs). Additionally, IMRT plans delivered a lower mean dose to the ipsilateral lung compared to VMAT plans. Gamma Knife SBRT plans achieves steeper dose falloff and minimizes radiation to normal lung tissue compared to VMAT and IMRT plans, but with longer delivery times. VMAT and IMRT plans displayed similar dose distributions for lung SBRT.

Evaluation of micro-remnant niduses of arteriovenous malformations post-gamma knife radiosurgery by 3D-rotational angiography.

PURPOSE: Recent innovations in radiological imaging have enabled the detection of micro-remnant niduses of arteriovenous malformations (AVMs) after gamma knife radiosurgery (GKS), which have not been previously perceptible. Herein, we focus on the difficulty of evaluating micro-remnant AVMs after GKS that are hardly perceptible on conventional examinations and propose integrating follow-up three-dimensional rotational angiography (3D-RA) in the previous gamma plan as a solution. METHODS: We retrospectively searched NTT Medical Center Tokyo hospital database for patients with AVMs who underwent both two-dimensional digital subtraction angiography (2D-DSA) and 3D-RA as follow-up for GKS from February 2021 to January 2024. Patients with suspected nidus occlusion on the latest non-contrast-enhanced magnetic resonance angiography (NC-MRA) were included, and contrast-enhanced magnetic resonance angiography (CE-MRA), 2D-DSA, and 3D-RA were evaluated. RESULTS: Twelve patients with 13 AVM sites were defined as having complete nidus occlusion on upfront NC-MRA. On 2D-DSA, seven AVM sites showed the presence of slight remaining AVMs based on the detection of remnant drainage veins, however the nidus was not detected in three cases. Nevertheless, 3D-RA detected micro-remnant niduses in all seven AVM sites, and four patients underwent re-GKS. Nine patients with ten AVM sites also underwent CE-MRA, and six AVM sites were diagnosed with radiation-induced parenchymal injury. CONCLUSION: Importing the 3D-RA image into the treatment planning has the potential to be more helpful than NC-MRA or CE-MRA to detect micro-remnant AVMs and evaluate the true remnant volume, and may contribute to a more detailed treatment planning, thereby improving the results of GKS retreatment.

A single-session stereotactic radiosurgery for vagal paraganglioma: Effective tumor reduction and innovative treatment option.

Background: Vagal paragangliomas (VPs) are rare tumors in the upper cervical region. Although surgical resection is the standard treatment for these tumors, it carries significant risks due to the tumor's high vascularity and proximity to vital structures. Stereotactic radiosurgery (SRS) for skull base paraganglioma could be a minimally invasive alternative. Case Description: We report the case of a 47-year-old man with a large, asymptomatic VP who was successfully treated with SRS with Gamma Knife Icon, which was performed in the parapharyngeal space (volume: 25.7 mL) using a marginal dose of 14 Gy to the 45% isodose line. This case illustrates the successful treatment of a lesion near the conventional limits (lower limit of C2 vertebral body) using noninvasive mask fixation. Excellent tumor control without neurological deficits was achieved for 25 months after SRS. The tumor volume decreased by 70% (final volume: 7.6 mL). Conclusion: This study demonstrates the utility of Gamma Knife Icon, which facilitates optimal SRS for upper cervical lesions, including VPs.

Patient reported outcomes and short-term adjustment trajectories following gamma knife radiosurgery for benign brain tumor.

PURPOSE: Patient reported outcomes (PROs) in the context of Gamma Knife Stereotactic Radiosurgery (GKSRS) for benign brain tumor have been under-researched. This study examined changes in PROs and adjustment trajectories post-GKSRS. METHOD: 50 adults (54% female) aged on average 53.18 (SD = 14.76) years with benign brain tumor were assessed 1 week before GKSRS, 1-2 weeks post-GKSRS, and at 3-month follow-up. Telephone-based questionnaires of anxiety and depressive symptoms, cognitive function, symptom burden, and health-related quality of life (HRQoL) were completed. RESULTS: Significant improvements in HRQoL, perceived cognitive ability, anxiety, and total brain tumor symptoms were evident between pre-GKSRS and 3-month follow-up. Conversely, there was a significant short-term increase in depressive symptoms at post-GKSRS; however, levels did not differ from pre-GKSRS at follow-up. No significant changes were evident on PROs of headaches or fatigue. About half of the participants (46-51%) experienced reliable improvement in global HRQoL, and one-third (31-34%) reported improved anxiety symptoms. Increased depressive symptoms was seen in 34% of participants post-GKSRS and 18% at follow-up. CONCLUSIONS: At 3 months post-GKSRS, improvements in HRQoL, anxiety, perceived cognitive ability, and total brain tumor symptoms were evident. Routine monitoring and support for pre-GKSRS anxiety and depressive symptoms post-GKSRS is recommended.

Individuals receiving Gamma Knife radiosurgery for benign brain tumor experience positive impacts on global, emotional, and physical HRQoL, perceived cognitive ability, anxiety, and overall brain tumor symptoms following treatment.Due to heightened levels of anxiety observed prior to treatment, routine screening and support for anxiety are recommended before individuals receive Gamma Knife radiosurgery.Symptoms of depression may increase following Gamma Knife radiosurgery, therefore routine monitoring and management of mood symptoms is recommended after treatment.Evidence-based psychological interventions are needed for healthcare professionals to support individuals undergoing Gamma Knife radiosurgery.

Considerations for the Use of Stereotactic Radiosurgery to Treat Large Arteriovenous Malformations.

Stereotactic radiosurgery (SRS) is an effective treatment strategy for cerebral arteriovenous malformations (AVMs). Aggressive treatment achieving complete obliteration is necessary to prevent further intracranial hemorrhage and neurological deficits. However, SRS treatment of large AVMs (>10 cm3) is challenging. To prevent toxicity in the normal brain tissue, it is imperative to reduce the radiation dose as the lesion volume increases; however, this also reduces the rate of obliteration. In this study, we review the various radiosurgical approaches for treating large AVMs and their outcomes, and suggest ways to improve treatment outcomes during SRS for large AVMs.

Comparative Performance of Autoencoders and Traditional Machine Learning Algorithms in Clinical Data Analysis for Predicting Post-Staged GKRS Tumor Dynamics.

Introduction: Accurate prediction of tumor dynamics following Gamma Knife radiosurgery (GKRS) is critical for optimizing treatment strategies for patients with brain metastases (BMs). Traditional machine learning (ML) algorithms have been widely used for this purpose; however, recent advancements in deep learning, such as autoencoders, offer the potential to enhance predictive accuracy. This study aims to evaluate the efficacy of autoencoders compared to traditional ML models in predicting tumor progression or regression after GKRS. Objectives: The primary objective of this study is to assess whether integrating autoencoder-derived features into traditional ML models can improve their performance in predicting tumor dynamics three months post-GKRS in patients with brain metastases. Methods: This retrospective analysis utilized clinical data from 77 patients treated at the "Prof. Dr. Nicolae Oblu" Emergency Clinic Hospital-Iasi. Twelve variables, including socio-demographic, clinical, treatment, and radiosurgery-related factors, were considered. Tumor progression or regression within three months post-GKRS was the primary outcome, with 71 cases of regression and 6 cases of progression. Traditional ML models, such as Logistic Regression, Support Vector Machine (SVM), K-Nearest Neighbors (KNN), Extra Trees, Random Forest, and XGBoost, were trained and evaluated. The study further explored the impact of incorporating features derived from autoencoders, particularly focusing on the effect of compression in the bottleneck layer on model performance. Results: Traditional ML models achieved accuracy rates ranging from 0.91 (KNN) to 1.00 (Extra Trees). Integrating autoencoder-derived features generally enhanced model performance. Logistic Regression saw an accuracy increase from 0.91 to 0.94, and SVM improved from 0.85 to 0.96. XGBoost maintained consistent performance with an accuracy of 0.94 and an AUC of 0.98, regardless of the feature set used. These results demonstrate that hybrid models combining deep learning and traditional ML techniques can improve predictive accuracy. Conclusion: The study highlights the potential of hybrid models incorporating autoencoder-derived features to enhance the predictive accuracy and robustness of traditional ML models in forecasting tumor dynamics post-GKRS. These advancements could significantly contribute to personalized medicine, enabling more precise and individualized treatment planning based on refined predictive insights, ultimately improving patient outcomes.

Comparison of two biologically effective dose calculation models applied to single fraction stereotactic radiosurgery.

BACKGROUND: Recent studies suggest strong correlations between Biologically Effective Doses (BED) and single fraction stereotactic radiosurgery treatment outcomes, as demonstrated for vestibular schwannomas (VS), arterio-venous malformations and pituitary adenomas. The BEDs calculated in these studies consider an uniform dose delivery where the spatio-temporal aspects of dose delivery were neglected. PURPOSE: The aim of the study is to quantify the discrepancies between the BED values calculated with a simplified model of uniform dose delivery against the more complex model that incorporates the temporo-spatial incrementation of dose delivery and the bi-exponential effect of the sub-lethal damage repair. METHODS: A software tool that computes the BED distributions based on individual isocenter dose matrices extracted from the GammaPlan (Elekta) treatment planning was developed. Two cohorts 5 VS and 5 jugular foramen schwannoma cases of various tumor volumes and isocenter number were utilized to benchmark the method. Their BEDs covering 98% of tumor volumes were compared against those determined with the uniform delivery model. RESULTS: The BEDs covering 98% of the tumor volumes as calculated with both models show an approximately linear dependency with the treatment time. For all studied cases, the uniform delivery model overestimates the BEDs calculated with the full spatio-temporal delivery model. This discrepancy seems to accentuate with the tumor volume and treatment complexity. CONCLUSIONS: Despite their resemblance, the BED distributions provide a plethora of BED measures more suitable to characterize clinical outcomes than the unique peripheral BED value calculated with the simplified model of uniform dose delivery.

Radioneuromodulation of Nucleus Accumbens for Addiction: The First Animal Study.

OBJECTIVE: Addiction is a serious spiral where negative events or relationships trigger a craving even when the situation is caused by the addiction in the first place. Nucleus accumbens is identified as an important hub for the neural pathways involved in the addictive behavior. Stimulation of this structure was demonstrated to be beneficial for addiction previously, but radioneuromodulation was never investigated until today. This study aimed to investigate if radioneuromodulation of the nucleus accumbens has any effect on alcohol addiction. METHODS: An addiction model was used on 36 Long-Evans rats (18 females/18 males), via a 2-bottle intermittent access protocol, and the trial group received 100 Gy of gamma irradiation to their bilateral nucleus accumbens. Rats were followed up for an additional 15 weeks. Multiple sets of a behavioral test battery, a 4-week abstinence period, and quinine adulteration challenges were used to evaluate responses. RESULTS: The experiment showed that the intervention reduced alcohol preference in the presence of aversive stimuli in female rats, compared with the nonirradiated control rats, because the trial group showed a 9.83-point decrease in alcohol preference rate under high-dose quinine adulteration compared with baseline, whereas the control group did not show any decrease. There were also implications of additional benefits regarding weight control in females and behavioral tests in males. No evident adverse effect was observed with the treatment. CONCLUSIONS: This study indicates that nucleus accumbens radioneuromodulation, although not significantly affecting baseline consumption, reduces intake when an aversive stimulus is involved, implying improved self-control.

Radiographic and neurological outcomes of Gamma Knife radiosurgery for lower cranial nerve schwannomas: a single-institution experience.

OBJECTIVE: Gamma Knife radiosurgery (GKRS) is widely used for treating small- to medium-sized or postoperative residual, recurrent lower cranial nerve schwannomas (LCNSs). This study aimed to evaluate the radiographic and neurological outcomes of GKRS for LCNS. METHODS: A total of 60 patients with 47 jugular foramen schwannomas (JFSs) and 13 hypoglossal nerve schwannomas (HNSs) who underwent GKRS were included. Dysphagia (40.4%) and hoarseness (23.4%) were the most common preexisting symptoms associated with JFS, whereas tongue deviation (53.8%) was prevalent in HNS. The median tumor volumes were 3.2 cm3 and 2.2 cm3 for JFSs and HNSs, respectively. The median marginal dose administered to the tumor was 13 Gy (range 12-15 Gy). The median follow-up duration was 52.8 months. RESULTS: Local tumor control was achieved in 91.5% of JFSs and 92.3% of HNSs. The preexisting neurological symptoms improved in 48.9% of patients with JFS and remained stable in 29.8%. However, 10 patients (21.3%) experienced exacerbation of symptoms associated with cranial nerves VII, VIII, IX, X, and XI. Among these, 3 patients (6.4%) exhibited persistent symptomatic deterioration. Patients with HNSs demonstrated a stable trajectory without symptom aggravation. Larger tumor volume and cystic portion were significantly associated with tumor progression (p = 0.017 and 0.003, respectively), and post-GKRS transient swelling was associated with neurological deterioration (p = 0.044). CONCLUSIONS: GKRS is an alternative treatment option for LCNS that reduces surgical morbidity and enhances tumor control. However, GKRS can potentially lead to neurological deterioration, necessitating extreme caution throughout the procedure, specifically for JFSs.

Vein of galen malformations: for patients and caregivers.

Vein of Galen malformations (VOGMs), also known as Vein of Galen Aneurysmal Malformations (VGAMs), are rare and complex cerebrovascular anomalies that pose significant diagnostic and therapeutic challenges. These malformations result from abnormal arteriovenous shunts during embryonic development, leading to a range of severe clinical manifestations, including high-output cardiac failure and hydrocephalus. Advances in prenatal imaging, particularly fetal MRI, have improved early detection, allowing for timely intervention. Endovascular techniques, especially transarterial embolization, have become the primary treatment modality, often preferred over surgical approaches due to their effectiveness and lower risk. However, challenges remain, particularly in managing these malformations in neonates and infants, where the risk of complications is high. Gamma Knife radiosurgery offers a non-invasive alternative for select cases, though its effects are gradual and may carry delayed risks. Despite advancements, the management of VOGMs continues to require a multidisciplinary approach, with ongoing research focused on improving outcomes through a better understanding of the genetic and molecular underpinnings of the disease. Future directions include the integration of genetic studies into clinical practice and the refinement of treatment strategies to optimize outcomes for this complex condition.

Stereotactic radiosurgery for anterior cranial fossa dural arteriovenous fistulas.

OBJECTIVE: Anterior cranial fossa (ACF) dural arteriovenous fistulas (DAVFs) are notoriously malignant vascular abnormalities, and their drainage into the cortical vein poses a high risk of intracranial hemorrhage (ICH). Stereotactic radiosurgery (SRS) is increasingly seen as an alternative to microsurgery or embolization for the treatment of DAVFs; however, researchers have yet to report on its applicability to ACF DAVFs. This paper summarizes the authors' experience in the use of SRS for ACF DAVFs. The authors' objective was to gain a preliminary overview of SRS outcomes in the treatment of ACF DAVFs. METHODS: This retrospective study examined all patients who underwent SRS for ACF DAVFs at a single academic medical center between November 2000 and November 2023. Demographic data, DAVF characteristics, and clinical outcomes were obtained from medical records. RESULTS: A total of 12 patients diagnosed with ACF DAVFs were treated using SRS. One patient was lost to follow-up. The mean age was 54.8 years and men comprised 82% of the cohort. The most common presenting symptoms included headache (n = 5), ocular symptoms (n = 3), seizure (n = 2), anosmia (n = 1), and tinnitus (n = 1). Two patients were asymptomatic. Four patients (36%) initially presented with ICH. Nine patients exhibited DAVF Cognard type IV, and 2 patients exhibited Cognard type III. DAVF obliteration in 7 of the 11 patients (64%) was confirmed by brain MR angiography (n = 4) or digital subtraction angiography (n = 3). No post-SRS episodes of ICH were reported. Most of the patients (10 of 11) reported improvements in clinical symptoms. CONCLUSIONS: SRS appears to be a viable alternative treatment for ACF DAVFs, particularly for patients who are not suitable candidates for surgery or those with an unfavorable angioarchitecture.

Stereotactic radio-neurosurgery for jugular foramen schwannomas.

BACKGROUND: Stereotactic radiosurgery (SRS) represents a minimally invasive and valuable alternative for jugular foramen schwannomas (JFS), both as upfront and/or adjuvant treatment (in hybrid approaches). METHODS: We conducted a retrospective review of our cases treated at the Lausanne University Hospital (CHUV) from June 2010 to October 2023. Eleven patients underwent SRS, among whom three had prior surgery, two in our center in the frame of a planned combined approach and one in another center. Two patients received "volume-staged" SRS. The mean age at SRS was 60 years (median 68; range 29-83). Cranial nerve (CN) symptoms were present in six patients, while five were asymptomatic. The mean tumor volume at SRS was 2.1 cc (median 1.2; range 0.068-7.3 cc), with a 12 Gy marginal dose prescribed in all cases. RESULTS: The mean follow-up period was 3.9 years (median 2, range 1-7). Cranial nerve function improved after SRS in six patients, while five remained stable. At the last follow-up, all tumors showed a decrease in volume, except for one patient, who underwent surgery at 18 months after SRS, for volumetric increase at 6 and 12 months, with further XII-th CN palsy and medulla oblongata compression. Although tumor decreased at 18 months, such patient needed microsurgical resection for symptom persistence and was further controlled. The mean tumor volume at 1 year post-SRS was 1.6 cc (median 0.55; range 0.028-7.77 cc), at 2 years was 1.31 cc (median 0.76; range 0.19-5), and at 3 years was 1.32 cc (median 0.59; range 0.23-4.8). No adverse radiation events were observed. CONCLUSIONS: Stereotactic radiosurgery is considered a safe and effective treatment for jugular foramen schwannomas, ensuring high rates of tumor control in all patients over the long term. The cranial nerve function improved after SRS in the 6 patients who had deficits and the other 5 patients who had no deficits remained asymptomatic. For larger tumors, combined/hybrid approaches can be a valuable alternative, to obtain tumor control and to preserve neurological function.

Stereotactic radiosurgery for intracranial dural arteriovenous fistulas: patient outcomes and lessons learned over a 3-decade single-center experience.

OBJECTIVE: The role of stereotactic radiosurgery (SRS) in the management of intracranial dural arteriovenous fistula (dAVF) is unclear given the rarity of this lesion and the variability in treatment paradigms. This study describes a 3-decade experience with the SRS technique and its outcomes for patients with dAVF. METHODS: The authors conducted a retrospective analysis of patients with dAVF who had undergone single-fraction SRS in the period from 1990 to 2021. The imaging modality initially used for targeting was angiography alone, then angiography plus MRI, and most recently MRI alone. RESULTS: Two hundred twenty-two patients underwent SRS alone (n = 56, 25%) or SRS plus embolization (n = 166, 75%), depending on the severity of symptoms or the presence of cortical venous drainage (CVD). Most patients were women (64%), and the median patient age was 60 years. Common presenting symptoms were pulsatile bruit (55%), visual change or chemosis (21%), headache (10%), and intracerebral hemorrhage (5%). The most frequent dAVF location was the transverse or sigmoid sinus (44%), followed by the cavernous sinus (24%), jugular bulb (9%), and torcula (5%). CVD was noted in 28% of cases, and venous ectasia in 5%. Borden dAVF types among the patients were I (72%), II (20%), and III (8%). Cognard dAVF types among the patients were I (44%), IIa (27%), IIb (5%), IIa+b (15%), III (4%), and IV (5%). The median SRS treatment volume was 7.6 cm3; the median margin and maximum doses were 18 and 36 Gy, respectively. Follow-up after SRS was available for 209 patients (median follow-up 31 months). Obliteration was noted in 75% of the patients (110/147) with follow-up vascular imaging; the median time to obliteration was 37 months. Multivariate analysis revealed that a cavernous sinus dAVF location was predictive of radiological obliteration (HR 1.86, 95% CI 1.08-3.18, p = 0.024). The absence of CVD was predictive of obliteration in subgroup analysis of non-cavernous sinus dAVF (HR 0.53, 95% CI 0.29-0.98, p = 0.04). Symptoms resolved in 86% of patients (160/185) with clinical follow-up. Twelve patients (5.4%) had complications related to angiography for SRS planning (n = 2, 0.9%), embolization (n = 3, 1.4%), post-SRS hemorrhage (n = 1, 0.5%), delayed sinus thrombosis (n = 1, 0.5%), radiation-induced tumors (n = 2, 0.9%), and chronic encapsulated expanding hematoma (n = 3, 1.4%). CONCLUSIONS: SRS alone or in conjunction with embolization provided obliteration and symptom relief for the majority of patients with dAVF, with a low rate of procedure-related morbidity. Patients are at risk for late radiation-related complications, which can require treatment many years after SRS.

Synthetic CT for gamma knife radiosurgery dose calculation: A feasibility study.

PURPOSE: To determine if MRI-based synthetic CTs (sCT), generated with no predefined pulse sequence, can be used for inhomogeneity correction in routine gamma knife radiosurgery (GKRS) treatment planning dose calculation. METHODS: Two sets of sCTs were generated from T1post and T2 images using cycleGAN. Twenty-eight patients (18 training, 10 validation) were retrospectively selected. The image quality of the generated sCTs was compared with the original CT (oCT) regarding the HU value preservation using histogram comparison, RMSE and MAE, and structural integrity. Dosimetric comparisons were also made among GKRS plans from 3 calculation approaches: TMR10 (oCT), and convolution (oCT and sCT), at four locations: original disease site, bone/tissue interface, air/tissue interface, and mid-brain. RESULTS: The study showed that sCTs and oCTs' HU were similar, with T2-sCT performing better. TMR10 significantly underdosed the target by a mean of 5.4% compared to the convolution algorithm. There was no significant difference in convolution algorithm shot time between the oCT and sCT generated with T2. The highest and lowest dosimetric differences between the two CTs were observed in the bone and air interface, respectively. Dosimetric differences of 3.3% were observed in sCT predicted from MRI with stereotactic frames, which was not included in the training sets. CONCLUSIONS: MRI-based sCT can be utilized for GKRS convolution dose calculation without the unnecessary radiation dose, and sCT without metal artifacts could be generated in framed cases. Larger datasets inclusive of all pulse sequences can improve the training set. Further investigation and validation studies are needed before clinical implementation.

Unforeseen outcomes: Unveiling cyst formation post stereotactic radiosurgery in brain arteriovenous malformations cases.

INTRODUCTION: Cyst formation after stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVMs) is a rare, delayed but important complication. Prompt recognition and appropriate treatment is essential for good outcome. METHODS: We analysed our institute's Gamma knife treatment records from 2008 to 2023 and analysed AVM treated patients by gamma knife radiosurgery (GKRS). Patients with cyst formation and with adequate follow up were identified. Clinical details, management and prognosis of these patients was studied in detail along with prior literature review. RESULTS: A total of 921 AVM patients were treated in the above period and 7 patients were identified with cyst formation. The mean nidus volume was 12.98 ml, the mean radio surgical marginal dose was 23.57 Gy and maximal dose 47.21 Gy. The mean interval gap between SRS and cyst detection was 6.45 years. The mean volume of cyst cavity formed was 47.85 ml. Patients presented either with features of raised intracranial pressure (3) or focal neurological deficits (3) or seizures (1). 3 patients had achieved angiographic nidus obliteration at the time of cyst detection. Treatment was mostly on surgical lines with cyst fenestration(2 patients), excision (3 patients) and emergency decompressive craniectomy (1 patient). 1 patient required additional Ommaya insertion. Conservative management was followed for 1 patient. Residual nidus was treated either by concomitant excision or embolization or redo GKRS. Favourable outcome was seen in 6 out of 7 patients (85.71%) post cyst management with symptomatic and radiological improvement whereas 1 patient (14.28%) died due to refractory status epilepticus secondary to malignant cerebral edema. CONCLUSION: Cyst formation after GKRS for AVM treatment is an often-neglected complication due to its low incidence and often long latency period. Long term follow up of patients is hence necessary for prompt recognition. Diagnostic DSA should be done in all patients with cysts to look for residual nidus. Asymptomatic ones can be followed up conservatively while surgical treatment is required for symptomatic cases. Ventricular diversion like Ommaya or cystoperitoneal shunt may be necessary in some cases. Treatment outcome is usually favourable provided timely detection is done.

[Radiosurgery for cerebral cavernous malformations: a systematic review]. / Radiokhirurgicheskoe lechenie kavernoznykh mal'formatsii golovnogo mozga: sistematicheskii obzor literatury.

BACKGROUND: Stereotactic radiosurgery (SRS) for cerebral cavernous malformations has been used for more than 30 years. However, indications for this method and outcomes are still discussable. OBJECTIVE: To analyze available literature data on SRS for cerebral cavernous malformations with assessment of indications for treatment, radiation parameters, radiological and clinical complications and outcomes. RESULTS: The final analysis included 20 reports describing post-SRS outcomes in 1834 patients with cerebral cavernous malformations. The main radiation parameter was mean radiation dose to the edge of cavernous malformation (prescribed dose, 13.25±2.16 Gy). In natural course of malformation, mean incidence of hemorrhages from cavernous malformation when counted after the second hemorrhage was 25.9±14.6%, after the patient's birth - 2.59±0.44%. Mean follow-up period after SRS was 66.7±24.1 months. Incidence of hemorrhages from cavernous malformation after SRS for the first 2 years of follow-up was assessed in 14 studies (4.67±3.51%). Incidence of hemorrhages ≥2 years after SRS was analyzed in 12 studies (1.55±0.8%). CONCLUSION: Despite significant global experience in SRS for cerebral cavernous malformations and many studies devoted to this problem, clear patient selection criteria have not yet been formulated. Modern selection principles have insufficient evidence base.

Effects on Gait and Balance of VIM Gamma Knife Radiosurgery in Essential Tremor.

INTRODUCTION: Essential tremor (ET) is the most common movement disorder, characterized by an action tremor in the upper limbs. Neurosurgical techniques targeting the thalamic ventrointermediate nucleus (VIM) including thermocoagulation demonstrated a potential risk for gait and posture worsening. This study evaluates the potential effect of VIM Gamma Knife radiosurgery (GKR) in ET on gait and posture performances. METHODS: We conducted a prospective study to quantitatively assess gait and balance in severe ET patients before and 1 year after unilateral GKR. Seventy-three patients were included in this series. RESULTS: First, we confirmed the unilateral GKR efficacy in severe ET patients: global tremor score and impairments in activities of daily living improved, respectively, by 67% and 71.7%. The global gait and posture analysis found no significant differences before and 1 year after GKR. Three patients (4.1%) developed mild to moderate gait and posture impairment with proprioceptive ataxia. All of these AEs were induced by a hyper-response to radiosurgery. CONCLUSIONS: Gait and posture performances were not statistically significant at the population. Nevertheless, gait and posture worsened in 4% of patients after GKR, all in the setting of hyper-response. This study shows that GKR may be a safe neurosurgical alternative to improve ADL in a population of patients with TE.