what if you cannot see the target two case studies of atlas to patient registration in trigeminal neuralgia radiosurgery

Introduction: Medically resistant trigeminal neuralgia (TN) is a wellsuited pathology to be treated by radiosurgery (RS). A significant percentage (60%-70%) of patients is expected to benefit from the RS treatment. Imaging is crucial to identify the target, though unfortunately in some cases the trigeminal nerve could not be visible even in high field magnetic resonance images (MRI). The aim of this work is to develop and relatively validate a method for the atlas-based identification of the target in those cases where the trigeminal nerve is not visible. Material Methods: The proposed method is based on the modification of a previously published approach for functional RS, adapted to the TN. A high resolution, high contrast volumetric T1-MRI atlas was nonrigidly registered to patient T1-MRI. Two patients scanned with a 3T T1-weighted-MRI and trigeminal nerve specific MR (Constructive Interference in Steady State – CISS) sequences were considered in this study. In both cases, the right-sided trigeminal nerve was not visible, while it was the contralateral nerve. For one patient, we simulated a potential radiosurgical treatment plan. The atlas-based localization accuracy of the trigeminal nerve was validated in a relative way evaluating the nearby structure continuity and the contralateral nerve localization

Spinal radiosurgery - efficacy and safety after prior conventional radiotherapy

<p>Abstract</p> <p>Background</p> <p>Conventional external beam radiotherapy is a standard procedure for treatment of spinal metastases. In case of progression spinal cord tolerance limits further radiotherapy in pre-irradiated areas. Spinal stereotactic radiotherapy is a non-invasive option to re-treat pre-irradiated patients. Nevertheless, spinal radiosurgery results in relevant dose deposition within the myelon with potential toxicity. Aim of the study was to retrospectively analyse the efficacy and feasibility for salvage radiosurgery of spinal metastases.</p> <p>Methods</p> <p>During a period of 4 years (2005-2009) 70 lesions in 54 patients were treated in 60 radiosurgery sessions and retrospectively analysed. Clinical (pain, sensory and motor deficit) and radiological (CT/MRI) follow-up data were collected prospectively after radiosurgery. Pain - as main symptom - was classified by the Visual Analogue Scale (VAS) score. Every patient received single session radiosurgery after having been treated first-line with conventionally fractionated radiotherapy. Kaplan-Meier method and life tables were used to analyse freedom from local failure and overall survival.</p> <p>Results</p> <p>At a median follow-up of 14.5 months the actuarial rates of freedom from local failure at 6/12/18 months were 93%, 88% and 85%, respectively. The median radiosurgery dose was 1 × 18 Gy (range 10-28 Gy) to the median 70% isodose. The VAS score of patients with pain (median 6) dropped significantly (median 4, p = 0.002). In 6 out of 7 patients worse sensory or motor deficit after SRS was caused by local or distant failures (diagnosed by CT/MRI). One patient with metastatic renal cell carcinoma developed a progressive complete paraparesis one year after the last treatment at lumbar level L3. Due to multiple surgery and radiosurgery treatments at the lumbar region and further local progression, the exact reason remained unclear. Apart from that, no CTC grade III or higher toxicity has been observed.</p> <p>Conclusions</p> <p>By applying spinal radiosurgery relevant radiation doses can be limited to small parts of the myelon. This prevents myelopathic side effects and makes it an effective and safe treatment option for well-suited patients. Especially for previously irradiated patients with local failure or pain salvage SRS represents a valuable treatment option with high local control rates, low toxicity and significant pain reduction.</p

Stereotactic body radiotherapy for centrally located early-stage non-small cell lung cancer or lung metastases from the RSSearch (R) patient registry

Background: The purpose of this study was to evaluate treatment patterns and outcomes of stereotactic body radiotherapy (SBRT) for centrally located primary non-small cell lung cancer (NSCLC) or lung metastases from the RSSearch (R) Patient Registry, an international, multi-center patient registry dedicated to radiosurgery and SBRT. Methods: Eligible patients included those with centrally located lung tumors clinically staged T1-T2 N0, M0, biopsy-confirmed NSCLC or lung metastases treated with SBRT between November 2004 and January 2014. Descriptive analysis was used to report patient demographics and treatment patterns. Overall survival (OS) and local control (LC) were determined using Kaplan-Meier method. Toxicity was reported using the Common Terminology Criteria for Adverse Events version 3.0. Results: In total, 111 patients with 114 centrally located lung tumors (48 T1-T2, N0, M0 NSCLC and 66 lung metastases) were treated with SBRT at 19 academic and community-based radiotherapy centers in the US and Germany. Median follow-up was 17 months (range, 1-72). Median age was 74 years for primary NSCLC patients and 65 years for lung metastases patients (p < 0.001). SBRT dose varied from 16 - 60 Gy (median 48 Gy) delivered in 1-5 fractions (median 4 fractions). Median dose to centrally located primary NSCLC was 48 Gy compared to 37.5 Gy for lung metastases (p = 0.0001) and median BED10 was 105.6 Gy for primary NSCLC and 93.6 Gy for lung metastases (p = 0.0005). Two-year OS for T1N0M0 and T2N0M0 NSCLC was 79 and 32.1 %, respectively (p = 0.009) and 2-year OS for lung metastases was 49.6 %. Two-year LC was 76.4 and 69.8 % for primary NSCLC and lung metastases, respectively. Toxicity was low with no Grade 3 or higher acute or late toxicities. Conclusion: Overall, patients with centrally located primary NSCLC were older and received higher doses of SBRT than those with lung metastases. Despite these differences, LC and OS was favorable for patients with central lung tumors treated with SBRT. Reported toxicity was low, although low grade toxicities were observed in patients where dose tolerances approached or exceeded published guidelines. Prospective studies are needed to further define the optimal SBRT dose for this cohort of patients

Vestibular Function and Quality of Life in Vestibular Schwannoma: Does Size Matter?

Objectives: Patients with vestibular schwannoma (VS) frequently suffer from disabling vestibular symptoms. This prospective follow-up study evaluates vestibular and auditory function and impairment of quality of life due to vertigo, dizziness, and imbalance in patients with unilateral VS of different sizes before/after microsurgical or radiosurgical treatment. Methods: Thirty-eight patients with unilateral VS were included. Twenty-two received microsurgery, 16 CyberKnife radiosurgery. Two follow-ups took place after a median of 50 and 186.5 days. Patients received a standardized neuro-ophthalmological examination, electronystagmography with bithermal caloric testing, and pure-tone audiometry. Quality of life was evaluated with the Dizziness Handicap Inventory (DHI). Patient data was grouped and analyzed according to the size of the VS (group 1: <20 mm vs group 2: ≥20 mm). Results: In group 1, the median loss of vestibular function was +10.5% as calculated by Jongkees Formula (range −43 to +52; group 2: median +36%, range −56 to +90). The median change of DHI scores was −9 in group 1 (range −68 to 30) and +2 in group 2 (−54;+20). Median loss of hearing was 4 dB (−42; 93) in group 1 and 12 dB in group 2 (5; 42). Conclusion: Loss of vestibular function in VS clearly correlates with tumor size. However, loss of vestibular function was not strictly associated with a long-term deterioration of quality of life. This may be due to central compensation of vestibular deficits in long-standing large tumors. Loss of hearing before treatment was significantly influenced by the age of the patient but not by tumor size. At follow-up 1 and 2, hearing was significantly influenced by the size of the VS and the manner of treatment

Quality of life in the follow-up of uveal melanoma patients after CyberKnife treatment

To assess quality of life in uveal melanoma patients within the first and second year after CyberKnife radiosurgery. Overall, 91 uveal melanoma patients were evaluated for quality of life through the Short-form (SF-12) Health Survey at baseline and at every follow-up visit over 2 years after CyberKnife radiosurgery. Statistical analysis was carried out using SF Health Outcomes Scoring Software and included subgroup analysis of patients developing secondary glaucoma and of patients maintaining a best corrected visual acuity (BCVA) of the treated eye of 0.5 log(MAR) or better. Analysis of variance, Greenhouse-Geisser correction, Student's t-test, and Fisher's exact test were used to determine statistical significance. Physical Functioning (PF) and Role Physical (RP) showed a significant decrease after CyberKnife radiosurgery, whereas Mental Health (MH) improved (P=0.007, P<0.0001 and P=0.023). MH and Social Functioning (SF) increased significantly (P=0.0003 and 0.026) in the no glaucoma group, MH being higher compared with glaucoma patients (P=0.02). PF and RP were significantly higher in patients with higher BCVA at the second follow-up (P=0.02). RP decreased in patients with BCVA<0.5 log(MAR) (P=0.013). Vitality (VT) increased significantly in patients whose BCVA could be preserved (P=0.031). Neither tumor localization nor size influenced the development of secondary glaucoma or change in BCVA. Although PF and RP decreased over time, MH improved continuously. Prevention of secondary glaucoma has a significant influence on both SF and MH, whereas preservation of BCVA affects VT. Emotional stability throughout follow-up contributes positively toward overall quality of life. CyberKnife radiosurgery may contribute to attenuation of emotional distress in uveal melanoma patients

Intracranial Hemorrhage in Patients with Anticoagulant Therapy Undergoing Stereotactic Radiosurgery for Brain Metastases: A Bi-Institutional Analysis

Background: Stereotactic radiosurgery (SRS) is a well-established treatment modality for brain metastases (BM). Given the manifold implications of metastatic cancer on the body, affected patients have an increased risk of comorbidities, such as atrial fibrillation (AF) and venous thromboembolism (VTE), which includes pulmonary embolism (PE) and deep-vein thrombosis (DVT). These may require therapeutic anticoagulant therapy (ACT). Limited data are available on the risk of intracranial hemorrhage (ICH) after SRS for patients with BM who are receiving ACT. This bi-institutional analysis aimed to describe the bleeding risk for this patient subgroup. Methods: Patients with ACT at the time of single-fraction SRS for BM from two institutions were eligible for analysis. The cumulative incidence of ICH with death as a competing event was assessed during follow-up with magnetic resonance imaging or computed tomography. Results: Forty-one patients with 97 BM were included in the analyses. The median follow-up was 8.2 months (range: 1.7-77.5 months). The median and mean BM volumes were 0.47 and 1.19 cubic centimeters, respectively. The most common reasons for ACT were PE (41%), AF (34%), and DVT (7%). The ACT was mostly performed utilizing phenprocoumon (37%), novel oral anticoagulants (32%), or low-molecular-weight heparin (20%). Nine BM from a group of five patients with ICH after SRS were identified: none of them caused neurological or any other deficits. The 6-, 12-, and 18-month cumulative bleeding incidences per metastasis were 2.1%, 12.4%, and 12.4%, respectively. The metastases with previous bleeding events and those originating from malignant melanomas were found to more frequently demonstrate ICH after SRS (p = 0.02, p = 0.01). No surgical or medical intervention was necessary for ICH management, and no observed death was associated with an ICH. Conclusion: Patients receiving an ACT and single-fraction SRS for small- to medium-sized BM did not seem to have a clinically relevant risk of ICH. Previous bleeding and metastases originating from a malignant melanoma may favor bleeding events after SRS. Further studies are needed to validate our reported findings

Meningioma involving the superior sagittal sinus: long-term outcome after robotic radiosurgery in primary and recurrent situation

ObjectiveTreatment for meningiomas involving the superior sagittal sinus (SSS) is challenging and proved to be associated with higher risks compared to other brain locations. Therapeutical strategies may be either microsurgical (sub-)total resection or adjuvant radiation, or a combination of both. Thrombosis or SSS occlusion following resection or radiosurgery needs to be further elucidated to assess whether single or combined treatment is superior. We here present tumor control and side effect data of robotic radiosurgery (RRS) in combination with or without microsurgery.MethodsFrom our prospective database, we identified 137 patients with WHO grade I meningioma involving the SSS consecutively treated between 2005 and 2020. Treatment decisions were interdisciplinary. Patients underwent RRS as initial/solitary treatment (group 1), as adjuvant treatment after subtotal resection (group 2), or due to recurrent tumor growth after preceding microsurgery (group 3). Positive tumor response was assessed by MRI and defined as reduction of more than 50% of volume. Study endpoints were time to recurrence (TTR), time to RRS, risk factors for decreased survival, and side effects. Overall and specific recurrence rates for treatment groups were analyzed. Side effect data included therapy-related morbidity during follow-up (FU).ResultsA total of 137 patients (median age, 58.3 years) with SSS meningiomas WHO grade I were analyzed: 51 patients (37.2%) in group 1, 15 patients (11.0%) in group 2, and 71 patients (51.8%) in group 3. Positive MR (morphological response) to therapy was achieved in 50 patients (36.4%), no response was observed in 25 patients (18.2%), and radiological tumor progression was detected in 8 patients (5.8%). Overall 5-year probability of tumor recurrence was 15.8% (median TTR, 41.6 months). Five-year probabilities of recurrence were 0%, 8.3.%, and 21.5% for groups 1–3 (p = 0.06). In multivariate analysis, tumor volume was significantly associated with extent of SSS occlusion (p = 0.026) and sex (p = 0.011). Tumor volume significantly correlated with TTR (p = 0.0046). Acute sinus venous thrombosis or venous congestion-associated bleedings did not occur in any of the groups.ConclusionRRS for grade I meningiomas with SSS involvement represents a good option as first-line treatment, occasionally also in recurrent and adjuvant scenarios as part of a multimodal treatment strategy

Magnetic Resonance Imaging-Based Robotic Radiosurgery of Arteriovenous Malformations

Objective: CyberKnife offers CT- and MRI-based treatment planning without the need for stereotactically acquired DSA. The literature on CyberKnife treatment of cerebral AVMs is sparse. Here, a large series focusing on cerebral AVMs treated by the frameless CyberKnife stereotactic radiosurgery (SRS) system was analyzed. Methods: In this retrospective study, patients with cerebral AVMs treated by CyberKnife SRS between 2005 and 2019 were included. Planning was MRI- and CT-based. Conventional DSA was not coregistered to the MRI and CT scans used for treatment planning and was only used as an adjunct. Obliteration dynamics and clinical outcome were analyzed. Results: 215 patients were included. 53.0% received SRS as first treatment; the rest underwent previous surgery, embolization, SRS, or a combination. Most AVMs were classified as Spetzler-Martin grade I to III (54.9%). Hemorrhage before treatment occurred in 46.0%. Patients suffered from headache (28.8%), and seizures (14.0%) in the majority of cases. The median SRS dose was 18 Gy and the median target volume was 2.4 cm³. New neurological deficits occurred in 5.1% after SRS, with all but one patient recovering. The yearly post-SRS hemorrhage incidence was 1.3%. In 152 patients who were followed-up for at least three years, 47.4% showed complete AVM obliteration within this period. Cox regression analysis revealed Spetzler-Martin grade (P = 0.006) to be the only independent predictor of complete obliteration. Conclusions: Although data on radiotherapy of AVMs is available, this is one of the largest series, focusing exclusively on CyberKnife treatment. Safety and efficacy compared favorably to frame-based systems. Non-invasive treatment planning, with a frameless SRS robotic system might provide higher patient comfort, a less invasive treatment option, and lower radiation exposure

Convolutional Neural Networks to Detect Vestibular Schwannomas on Single MRI Slices: A Feasibility Study.

In this study. we aimed to detect vestibular schwannomas (VSs) in individual magnetic resonance imaging (MRI) slices by using a 2D-CNN. A pretrained CNN (ResNet-34) was retrained and internally validated using contrast-enhanced T1-weighted (T1c) MRI slices from one institution. In a second step, the model was externally validated using T1c- and T1-weighted (T1) slices from a different institution. As a substitute, bisected slices were used with and without tumors originating from whole transversal slices that contained part of the unilateral VS. The model predictions were assessed based on the categorical accuracy and confusion matrices. A total of 539, 94, and 74 patients were included for training, internal validation, and external T1c validation, respectively. This resulted in an accuracy of 0.949 (95% CI 0.935-0.963) for the internal validation and 0.912 (95% CI 0.866-0.958) for the external T1c validation. We suggest that 2D-CNNs might be a promising alternative to 2.5-/3D-CNNs for certain tasks thanks to the decreased demand for computational power and the fact that there is no need for segmentations. However, further research is needed on the difference between 2D-CNNs and more complex architectures

The Role of Stereotactic Radiosurgery in the Management of Foramen Magnum Meningiomas—A Multicenter Analysis and Review of the Literature

Background: Foramen magnum meningiomas (FMMs) represent a considerable neurosurgical challenge given their location and potential morbidity. Stereotactic radiosurgery (SRS) is an established non-invasive treatment modality for various benign and malignant brain tumors. However, reports on single-session or multisession SRS for the management and treatment of FMMs are exceedingly rare. We report the largest FMM SRS series to date and describe our multicenter treatment experience utilizing robotic radiosurgery. Methods: Patients who underwent SRS between 2005 and 2020 as a treatment for a FMM at six different centers were eligible for analysis. Results: Sixty-two patients met the inclusion criteria. The median follow-up was 28.9 months. The median prescription dose and isodose line were 14 Gy and 70%, respectively. Single-session SRS accounted for 81% of treatments. The remaining patients received three to five fractions, with doses ranging from 19.5 to 25 Gy. Ten (16%) patients were treated for a tumor recurrence after surgery, and thirteen (21%) underwent adjuvant treatment. The remaining 39 FMMs (63%) received SRS as their primary treatment. For patients with an upfront surgical resection, histopathological examination revealed 22 World Health Organization grade I tumors and one grade II FMM. The median tumor volume was 2.6 cubic centimeters. No local failures were observed throughout the available follow-up, including patients with a follow-up ≥ five years (16 patients), leading to an overall local control of 100%. Tumor volume significantly decreased after treatment, with a median volume reduction of 21% at the last available follow-up (p < 0.01). The one-, three-, and five-year progression-free survival were 100%, 96.6%, and 93.0%, respectively. Most patients showed stable (47%) or improved (21%) neurological deficits at the last follow-up. No high-grade adverse events were observed. Conclusions: SRS is an effective and safe treatment modality for FMMs. Despite the paucity of available data and previous reports, SRS should be considered for selected patients, especially those with subtotal tumor resections, recurrences, and patients not suitable for surgery