Postsurgical MRI Research Articles

NIMG-72. VOXEL-WISE, MULTIVARIABLE, COX PROPORTIONAL HAZARD STATISTICAL PARAMETER MAPPING TO INVESTIGATE THE INTERPLAY BETWEEN TUMOR LOCATION, PROGNOSTIC VARIABLES, AND EXPERIMENTAL TREATMENT IN A PHASE 3 TRIAL OF NEWLY-DIAGNOSED GLIOBLASTOMA TREATED WITH CHEMORADIATION WITH OR WITHOUT BEVACIZUMAB

Abstract BACKGROUND Tumor location is known to impact overall survival (OS) in glioblastoma. However, there is a lack of quantitative tools for studying the interplay between tumor location, prognostic variables, and treatments. In the current study we develop a voxel-wise statistical parameter mapping technique using a multivariable Cox regression model to describe the influence of tumor location on treatment effects in newly diagnosed glioblastoma. METHODS 598 newly diagnosed glioblastoma patients from the phase 3 AVAglio trial were studied. Areas of T2/FLAIR hyperintensity and resection cavities on post-surgical MRI scans were segmented and aligned to MNI atlas space. Voxel-wise Cox proportional hazards models for OS were run for each image voxel and included tumor presence in a specific voxel, age, MGMT promoter methylation, baseline tumor volume, and treatment (chemoradiation with or without bevacizumab). Results. After adjusting for other variables, tumor location was an independent predictor of favorable OS for tumors with involvement in the right prefrontal cortex (p<0.05, HR ranging ~0.48–0.65) and a predictor of shorter OS for tumors in the left mesial/basal temporo-occipital areas (p<0.05, HR ~3–6.2) and in the left hemisplenium of the corpus callosum (p<0.05, HR ~2.5–3). Baseline tumor volume (HR ~4–6 x10-6), MGMT status (HR ~0.38–0.41), and age (HR ~1.020–1.025) were significative predictors regardless of location (p<0.05 in all locations). Interestingly, chemoradiation plus bevacizumab treatment showed a favorable OS compared with chemoradiation alone for tumors with involvement in the right corticospinal tract, right motor and sensory cortices, and left hemisplenium of the corpus callosum (p<0.05, HR ~0.82). CONCLUSIONS Tumor involvement in the prefrontal cortex is associated with favorable prognosis, while tumors in mesial/basal temporo-occipital areas or splenium of the corpus callosum are associated with shorter OS. Chemoradiation plus bevacizumab may improve OS for tumors involving eloquent motor areas and the corticospinal tract.

Radiological Hypertrophic Olivary Degeneration Following Posterior Fossa Tumor Surgery

Hypertrophic olivary degeneration (HOD) is a rare form of transsynaptic degeneration, caused by injury to the dentato-rubro-olivary pathway (DROP). Radiologically, this manifests as T2 hyperintensity, with or without enlargement of the inferior olivary nucleus. The purpose of the study was to evaluate the incidence, associated imaging characteristics, potential etiologies, latency period, and temporal progression of HOD in patients undergoing surgical resection of posterior fossa tumors (PFTs). A retrospective analysis of patients with PFTs and postsurgical magnetic resonance imaging scans was conducted. HOD was diagnosed based on inferior olivary nucleus signal abnormalities and size changes. Demographics, tumor characteristics, time to HOD onset, involved DROP components, and clinical symptoms were recorded. HOD was seen in 40 (6.2%) patients following PFT surgery. Twenty six patients were aged 17 years or less, while the rest were aged more than 17years. Medulloblastoma was the most frequently diagnosed tumor type (n= 25), followed by pilocytic astrocytoma (n= 8), ependymoma (n= 6), and high-grade glioma (n= 1). No statistical association was found between the development of HOD and tumor grade (P= 0.882). Ataxia was the most commonly reported clinical symptom (n= 15). The time elapsed between surgery and the diagnosis of HOD varied, with median intervals of 1month, 5months, and 37months for different stages. Dentate nucleus was the most commonly affected component of the DROP (n= 36). HOD is a frequently overlooked postoperative complication following PFT resection. Increased recognition of HOD by neuroradiologists is essential for timely diagnosis and avoidance of unnecessary diagnostic procedures.

AUDIT TO EVALUATE CURRENT RADIOTHERAPY (RT) PLANNING PATHWAY: COULD CURRENT PRACTICE BE IMPROVED BY THE TIMING OF MAGNETIC RESONANCE IMAGING (MRI)?

Abstract AIMS To evaluate the current guidance for glioblastoma (GBM) and primary brain radiotherapy (RT) planning. Current practice in this centre utilises pre and post-surgical MRI for RT target delineation. This study aims to explore the practicality and impact of scheduling an RT planning-specific MRI no more than 2 weeks before RT treatment start date (TSD). Time from surgery to RT TSD will also be explored. METHOD Fifty GBM patients, treated between August 2022 and October 2023, were audited retrospectively. Included patients were treated with radical intent and must have had surgery or biopsy. Age, gender or performance status (PS) were excluded from audit criteria. Age of MRI used for RT planning and surgery to TSD was noted. RESULTS Early results showed that the average age of MRI used for RT planning was 7 weeks old and Surgery to TSD was 7 weeks. A new pathway was introduced after 37 patients as these results were considered unacceptable. The new pathway included 1 reserved MRI appointment and one reserved RT Mask/CT appointment per week. 13 patients’ pathways were audited after introduction of the new pathway. The results showed that the average age of MRI used for RT planning was 2 weeks old and surgery to TSD was 6 weeks. CONCLUSION Limitations of the audit included disparity between number of patients before and after introduction of the new pathway. This was because of the time limitation for completion of the study. Improvement was seen in timing of MRI to TSD. However, the small improvement in timing of surgery to TSD was impacted by human factors rather than organisational influence, for example, surgical deconditioning, delays for wound healing and patient choice. This study has shown that the ideal timing of MRI can be achieved.

Pre-and post-surgical non-functional pituitary adenomas and their relationship with high levels of serum glucose

Objectives This clinical, analytical, retro-prospective, auto-controlled, not randomized, and not blinded study, aimed to investigate the association of changes in the serum glucose levels with the pre-and-post changes in the size tumor in mm3 in the Non-Functional pituitary adenomas. Methods Pre-and post-surgical MRI, as well as the measurements in the serum glucose levels and immunohistochemical techniques were performed in all the patients in the study, with a mean followed-up until 208.57 days. A comparison was made between the reductions in tumor size of hormonally active pituitary adenomas (HSPAs) vs NFPAs. Results Seventy-four patients were included in this study, of whom, 46 were NFPAs. The decrease in the NFPAs tumor size after surgery was statistically significant (P ≤ 0.0001). The Mean of the differences of both type of tumors in mm3 were −9552 ± 10287. Pre-surgery, the mean of the HSPAs were 8.923 ± 2.078; and the NFPAs were 14.161 ± 1.912. The differences in the tumor size were statistically significant (p = 0.039). Post-surgical, the mean of the HSPAs were 2.079 ± 971, with a (p = 0.14): and the NFPAs were 4.609 ± 1.205. After surgery of the NFPAs, most of the patients-maintained serum levels ≤ 100 mg/dL, with a statistical significance (P ≤ 0.0003). Conclusion This study demonstrates for the first time the correlation between the presence of pre-and post- surgical changes in the NFPAs, with modifications in the levels of serum glucose, and the comparison, pre- and post-surgical between the tumor size of HSPAs and NFPAs.

Trouillas’s Grading and Post-Surgical Tumor Residue Assessment in Pituitary Adenomas: The Importance of the Multidisciplinary Approach

Background: We aim to assess the role of a multidisciplinary approach in pituitary adenomas (PitNETs) classification, evaluate criteria concordance, and compare intraoperative assessments with post-operative MRIs for tumor remnants. Methods: Clinical, radiological, histological, and intra- and post-operative data of the treated PitNETs were extracted from prospectively created records. PitNETs were graded according to Trouillas, and the evaluation of the tumor remnants was recorded. Results: Of 362 PitNETs, 306 underwent surgery, with Trouillas grading assigned to 296. Eight-nine radiologically non-invasive PitNETs progressed to grades 1b (27), 2a (42), or 2b (20) due to proliferative or surgical invasiveness criteria. Twenty-six radiologically invasive tumors were graded 2b due to proliferative criteria. Surgical resection details and post-surgical MRI findings revealed that residual tumors were more common in grades 2a and 2b. During surgery, small tumor remnants were documented in 14 patients which were not visible on post-surgical MRI. Post-surgical MRIs identified remnants in 19 PitNETs not seen during surgery, located in lateral recesses of the sella (4), retrosellar (2), or suprasellar regions (7), along the medial wall of the cavernous sinus (6). Conclusions: The Pituitary Board allows for the correct grading of PitNETs to be obtained and an accurate identification of high-risk patients who should undergo closer surveillance due to tumor remnants.

NIMG-68. TEMPORAL CHANGES IN TUMOR COMPOSITION DIFFER ACROSS TUMOR GRADE IN GLIOMA

Abstract Gliomas are the most common primary adult brain tumor in the United States and their biological heterogeneity makes it difficult to assess and treat tumor progression over time. This study used conventional MRI tumor segmentations to determine longitudinal growth differences between low grade (≤ G2), G3, and G4 gliomas. A total of 60 patients with at least three scans collected before death were organized into low-grade (n = 9), G3 (n = 13), and G4 (n = 38) gliomas at initial diagnosis. T1, T1C, FLAIR, and T2 images from every timepoint across all patients were used as input for tumor segmentation, using BraTS, to segment contrast enhancement (CE), FLAIR hyperintensity (FH), and the necrotic core (NC). Volumes within each segmentation and the time between each subsequent MRI was calculated, where the first post-surgical MRI was considered time 0. Linear mixed models were fitted for each segmentation volume, where Time, Group (i.e., G2-4) and their interaction (Group*Time) were fixed effects and subject was a random effect. We found that Time and Group*Time interaction were significant predictors of FH growth (p < 0.001 and 0.04, respectively); however, no group-level differences were observed in FH volumes over time. Group was the only significant predictor of CE growth (p = 0.006). Specifically, G4 growth was greater than G2 and had a trending increase than G3 (p = 0.003 and 0.08, respectively). Group, Time, and Group*Time were all significant predictors of NC growth (p = 0.04, 0.001, and 0.01, respectively). G4 NC growth was significantly greater than both G2 and G3 (both p < 0.05). No difference any of these tumor segmentations growth between G2 and G3 was detected. These results further show the heterogeneity in glioma growth over time and the necessity to assess how treatment effects longitudinal tumor composition progression and overall survival.

THU102 A Case Of Papillary Craniopharyngioma WHO Grade 1 Turned Into Abscess

Abstract Disclosure: R.J. Shah: None. J. Patel: None. P.A. Belany: None. Craniopharyngioma is a rare primary brain tumor located in the suprasellar region. Papillary craniopharyngiomas (PC) occur mostly in adults, between age 40-50. Despite surgery being the primary treatment, PCs have a high tendency for relapse. We present a case of PC WHO grade 1, positive for BRAF V600E mutation concerning for regrowth 10 months following surgical resection. A 45-year-old male presented to the emergency department with complaint of right orbital headaches, vision change and severe fatigue. CT head was normal and was discharged home. Headaches, fatigue, and vision change progressively worsened over the next week with new symptoms of erectile dysfunction, low libido, weight loss, polyuria, polydipsia and proximal muscle weakness developing. Morning labs showed FT4 0.5ng/dl, TSH 2.32uIU, cortisol 1.5ug/dl, ACTH 14 pg/mL, FSH 1.5mIU/mL, LH 0.2mIU/mL, total testosterone 6ng/dl, prolactin 17.5ng/mL, IGF-1 134 ng/mL and GH 0.2ng/dl concerning for panhypopituitarism. Chemistry panel was unremarkable. MRI pituitary confirmed sellar mass measuring 2.1x1.3x2.1cm compressing the optic chiasm. Evaluated by endocrinology, patient was started on hydrocortisone, levothyroxine and desmopressin and referred to neurosurgery. Following endoscopic endonasal approach (EEA), pathology showed PC WHO Grade 1 and molecular testing positive for BRAF V600E mutation. Two-month post-surgical MRI showed residual 8mm lesion. Active surveillance showed regrowth of sellar lesion to 1.8 cm with optic chiasm compression ten months following EEA. Repeat EEA was done with concern for relapse. Surprisingly, intraoperative purulent fluid draining from the sella was found and positive for Acinetobacter. Sellar abscess was drained and he received six weeks of intravenous antibiotics. Repeat MRI showed resolution of the entire sellar lesion, his vision normalized and continued to be on hormone replacement for panhypopituitarism. PCs are locally aggressive suprasellar lesions that can reach a large size prior to clinical symptoms developing. Around 90% of PC are positive for BRAF V600 mutation. Surgical resection and radiotherapy are the primary treatment, but newer studies have demonstrated tumor regression using BRAF targeted agents following relapse. Our case demonstrates a pituitary abscess (PA) found intraoperatively that was originally suspicious for tumor recurrence. PA is a rare and serious intrasellar infection associated with high mortality. It is difficult to diagnose preoperatively and can be misdiagnosed as recurrence or residual tissue. PA can be primary or secondary depending on etiology. PA associated with residual craniopharyngioma tissue is extremely rare and the exact pathophysiology is not well understood. If no evidence of sepsis or meningitis, treatment with transsphenoidal decompression and intravenous antibiotics has good clinical outcomes. Presentation: Thursday, June 15, 2023

OS09.4.A RANO 2.0: UPDATE TO THE RESPONSE ASSESSMENT IN NEURO-ONCOLOGY (RANO) CRITERIA FOR HIGH- AND LOW-GRADE GLIOMAS IN ADULTS

Abstract BACKGROUND The Response Assessment in Neuro-Oncology (RANO) criteria for high-grade gliomas (RANO-HGG) and low-grade gliomas (RANO-LGG) were developed to improve reliability of response assessment in glioma trials. Over time some limitations of these criteria were identified, and uncertainty emerged regarding integrating features of the modified RANO (mRANO) or the immunotherapy RANO (iRANO) criteria. MATERIAL AND METHODS Informed by data from a cohort of glioblastoma patients and other evaluations of RANO criteria that allowed evaluation of features of the different criteria, the RANO working group developed updates to the RANO criteria (RANO 2.0). RESULTS Based on the 2021 WHO classification of gliomas, we recommend a standard set of criteria for both high and low-grade gliomas, to be used for all trials regardless of the treatment modalities being evaluated. In the newly diagnosed setting, the post-radiotherapy MRI, rather than the post-surgical MRI, will be used as the baseline for future comparison. Since the incidence of pseudoprogression is high in the 12 weeks following radiotherapy, continuation of treatment and confirmation of progression during this period with a repeat MRI, or histopathologic evidence of unequivocal recurrent tumor, is required to define tumor progression. However, confirmation scans are not mandatory after this period nor for recurrent tumors. For treatments with a high likelihood of pseudoprogression, mandatory confirmation of progression with a repeat MRI is highly recommended. The primary measurement remains the maximum cross-sectional area of tumor (2-dimensional) but volumetric measurements are an option. For IDH-wildtype glioblastoma, the non-enhancing disease will no longer be evaluated. In IDH-mutated tumors with a significant non-enhancing component, clinical trials may require evaluating both the enhancing and non-enhancing tumor components for response assessment. CONCLUSION These criteria represent a work in progress that will hopefully improve the assessment of response in glioma trials. Future updates will incorporate novel developments, advanced imaging techniques, and endpoints as they become validated.

CLRM-07 RANO 2.0: PROPOSAL FOR AN UPDATE TO THE RESPONSE ASSESSMENT IN NEURO-ONCOLOGY (RANO) CRITERIA FOR HIGH- AND LOW-GRADE GLIOMAS IN ADULTS

Abstract The Response Assessment in Neuro-Oncology (RANO) criteria for high-grade gliomas (RANO-HGG) and low-grade gliomas (RANO-LGG) were developed to improve the reliability of response assessment in glioma trials. Over time some limitations of these criteria were identified, and uncertainty emerged regarding integrating features of the modified RANO (mRANO) or the immunotherapy RANO (iRANO) criteria. Informed by data from a cohort of glioblastoma patients and other evaluations of RANO criteria that allowed evaluation of features of the different criteria, we propose updates to the RANO criteria (RANO 2.0). Based on the 2021 WHO classification of gliomas, we recommend a standard set of criteria for both high and low-grade gliomas, to be used for all trials regardless of the treatment modalities being evaluated. In the newly diagnosed setting, the post-radiotherapy MRI, rather than the post-surgical MRI, will be used as the baseline for future comparison. Since the incidence of pseudoprogression is high in the 12 weeks following radiotherapy, continuation of treatment and confirmation of progression during this period with a repeat MRI, or histopathologic evidence of unequivocal recurrent tumor, is required to define tumor progression. However, confirmation scans are not mandatory after this period nor for recurrent tumors. For treatments with a high likelihood of pseudoprogression, mandatory confirmation of progression with a repeat MRI is an option. The primary measurement remains the maximum cross-sectional area of tumor (2-dimensional) but volumetric measurements are an option. For IDH-wildtype glioblastoma, the non-enhancing disease will no longer be evaluated. In IDH-mutated tumors with a significant non-enhancing component, clinical trials may require evaluating both the enhancing and non-enhancing tumor components for response assessment.

Clinicopathological and Neuroimaging Features of Primary Gliosarcoma: A Case Series and Review of Literature

Gliosarcoma (GS) is a rare primary high-grade brain neoplasm with a poor prognosis and challenging surgical resection. Although it is now considered a morphologic variant of IDH-wildtype glioblastoma (World Health Organization Classification of Tumours 2021), GS may display peculiarities that hamper both surgical and oncological management. In this retrospective study, we searched our registry for histologically confirmed GS patients between 2006 and 2020. Cases were reviewed for clinical information, pathologic characteristics, imaging findings, management, and outcome. 21 patients with histologically confirmed GS were identified with a median age of 62years. Twelve were men and 9 women. The temporal lobe was the most common location (9 patients, 42.9%). Nineteen patients underwent surgical resection, and only 4 (19%) demonstrated gross total resection on postsurgical MRI, with an overall median survival of 7months (range, 0.5-37). Diagnostic MRI demonstrated heterogenous lesions with necrotic-cystic areas and a ring-enhancement pattern. Only 1 case of extracranial extension was seen in our sample, and no patient showed distant metastases. The rarity of primary GS and the absence of specific therapeutic guidelines represent a significant clinical challenge. Our study provides a comprehensive analysis of clinical and neuroimaging characteristics in a real-world patient cohort and compares our findings with the available literature.

RANO 2.0: Proposal for an update to the Response Assessment in Neuro-Oncology (RANO) criteria for high- and low-grade gliomas in adults.

2017 Background: Response Assessment in Neuro-Oncology (RANO) criteria for high-grade and low-grade glioma (HGG and LGG) were developed to improve reliability of response assessment in glioma trials. Several limitations of the original RANO criteria have been reported. Methods: To address limitations of the original RANO criteria, a large cohort of patients with newly diagnosed and recurrent glioblastoma were evaluated comparing RANO-HGG with modified RANO (mRANO) and immunotherapy RANO (iRANO) criteria to inform the following proposed updates (RANO 2.0). Results: Based on the 2021 WHO classification of glioma, we recommend a single common set of criteria for all gliomas regardless of WHO grade and IDH mutational status. These criteria will be used for all trials regardless of the treatment modalities being evaluated. In newly diagnosed glioblastoma, the post-radiotherapy MRI, usually obtained approximately 4 weeks after completion of radiotherapy, rather than the post-surgical MRI as proposed in original RANO criteria, will be used as the baseline for comparison of subsequent scans. Since the incidence of pseudoprogression is high in the first 3 months following radiotherapy, confirmation of progression during this period with a repeat MRI (in 4-8 weeks) will be required for determining radiographic progression of disease (PD) if the patient is clinically stable. However, confirmation scans are not mandatory after this period nor for recurrent tumors since these scans do not appear to improve reliability in determining progression. For agents with a high likelihood of producing pseudoprogression such as viral therapies and some other immunotherapies, mandatory confirmation of progression with a repeat MRI is an option. The primary measurement will remain the 2-dimensional maximum cross-sectional area of tumor as the simplest method, but where resources are available, volumetric measurements are an option. For IDH wild-type tumors with contrast enhancement, non-enhancing tumor will no longer be evaluated with the possible exception of patients receiving antiangiogenic therapies. However, in tumors with a significant non-enhancing component, both the contrast enhancing and non-enhancing components will be evaluated as target lesions. Conclusions: We hope that these and other proposed changes by the RANO working group will improve response assessment in glioma clinical trials and help the development of more effective therapy for patients.

Subject-Specific Modeling of Implant Placement for Type I Thyroplasty Surgery.

Type I thyroplasty is widely used to improve voice production in patients affected by unilateral vocal fold paralysis. Almost two-thirds of laryngologists report using Silastic® implants to medialize the vocal fold, with implant size, shape, and location determined experientially. However, post-surgical complications arising from this procedure (extrusion, migration, resizing) necessitate revision in 4.5-16% of patients. To improve initial surgical outcomes, we have developed a subject-specific modeling tool, PhonoSim, which uses model reconstruction from MRI scans to predict the optimal implantation location. Eleven vocal fold sample sides from eight larynges of New Zealand white rabbits were randomized to two groups: PhonoSim informed (n = 6), and control (no model guidance, n = 5). Larynges were scanned ex vivo in the abducted configuration using a vertical-bore 11.7T microimaging system, and images were used for subject-specific modeling. The PhonoSim tool simulated vocal fold adduction for multiple implant location placements to evaluate vocal fold adduction at the medial surface. The best implant placement coordinates were output for the 6 samples in the PhonoSim group. Control placements were determined by the same surgeon based on anatomical landmarks. Post-surgical MRI scans were performed for all samples to evaluate medialization in implanted vocal folds. Results show that PhonoSim-guided implantation achieved higher vocal fold medialization relative to controls (28 to 55% vs. - 29 to 39% respectively, in the glottal area reduction), suggesting that this tool has the potential to improve outcomes and revision rates for type I thyroplasty.

Pre- and post-clinical–radiological and surgical evaluation of patients with pituitary adenoma and metabolic syndrome

Background Pituitary adenomas are benign tumors located in the anterior hypophysis. Its appearance is associated with the development of parameters related to metabolic syndrome; therefore, surgical treatment could reduce associated morbimortality. Methods Pre- and post-surgical MRI, using the Hardy–Wilson and Knosp classification, and clinical data according to the American Association of Clinical Endocrinology (AACE) criteria for metabolic syndrome: all the patients were followed-up until 208.57 days were reviewed on 217 consecutive patients with pituitary surgery. Results Seventy-four patients were included in this study. There was a significant reduction in tumor size in mm3 [average pre- and post-surgery respectively: 12,362 mm3 (±12,397); 3,910 mm3 (±7,160)], (p < 0.0001). This was confirmed by the Hardy–Wilson and Knosp classification, where most patients went from grade IV C (33.7%) to grade 0 (12.1%), IA (20.2%), IIB (21.36%), and IIC (16.2%); as well as from grade 4 (24.3%) to grade 0 (45.9%), respectively. After surgery, there were statistically significant reductions in total serum levels of glucose [average pre- and post-surgery, respectively: 116 mg/dL (±26.9); 90 mg/dL (±10.2)], (p < 0.001), triglycerides [average pre- and post-surgery, 240 mg/dL (±102); 171 mg/dL (±60.5)], (p = 0.001); and HDL-c [average pre- and post-surgery, respectively: 39 mg/dL (±11.8); 44.6 mg/dL (±8.4)], (p = 0.029). The other parameters remained unchanged. Conclusion This is the first study to demonstrate the relationship between the presence of pituitary adenoma and significative changes in serum glucose, triglycerides and c-HDL related to metabolic syndrome.

Fetal MRI prior to intrauterine surgery of open neural tube defects: What does the radiologist need to know.

The management of myelomeningocele study trial showed significant prognostic improvement in fetal repair before 26weeks of gestation. Hence, surgery in utero represents the best treatment option for open-neural tube defects (NTDs). Fetal surgery of open-NTDs has specific inclusion and exclusion criteria, which can be adequately studied with fetal MRI. The main concern: the spine (spinal defects other than Myelomeningocele and Myeloschisis, the level of the lesion higher than T1 or lower than S1 and the degree of kyphosis ≥ 30°), the skull/brain (no cerebellum herniation and Chiari II malformation and the presence of any intracranial abnormality unrelated to open NTDs), the uterus (cervix length less than 2cm, multiple gestations and placental and uterine abnormalities) and any other fetal abnormality not attributed to spinal defect. In this review, we describe the fundamental role of fetal MRI in supporting therapeutic decisions in pre-surgery intrauterine planning through the accurate and comprehensive description of findings, providing a proposal of a structured report. In addition, we describe how post-surgical MRI is important in investigating the effectiveness of surgery and detecting repairing complications.

P17.14.B Strategy of the recurrent Glioblastoma treatment. Three neuro-oncology centers study

Abstract Background The prognosis for patients with Glioblastoma (GBM) remains dismal. The most aggressive multimodal therapy (maximally radical and safe tumor resection, followed by the Stupp protocol oncotherapy) has yielded the best treatment outcomes. Notwithstanding the slowly prolonged patient′s overall survival, this tumor inevitable recurs. An optimal therapy of the recurrent GBM is still a controversial theme.The aim of our study is to evaluate our treatment strategy of recurrent GBM. Material and Methods For this study, we retrospectively selected a group of resected recurrent GBM patients in a period from June 1, 2009 to December 31, 2019, which were treated in tree Czech neuro-oncologic centers. All patients underwent early post-surgical MRI (within 72 h) to determine resection radicality. Following resection, patients received periodic checkups with MRI every 3 months until death. Patients with psedoprogession were excluded. Information about all surgeries, oncotherapies, patient clinical condition, MRI, PET/CT, and results of histological, immunohistochemical, molecular genetic, and cytogenetic investigations was gathered.We consider surgery for recurrent GBM in case, if: 1.The tumor volume increasing &amp;gt; 20-30% or tumor rediscovery after radiologic disappearing. 2.Clinic condition - Karnofsky score (KS) ≥ 70% and Performance status (PS) WHO ≤ gr. 2. 3.Localized tumor, without multilfocality. 4.Assumed the least tumor volume reduction &amp;gt; 80%. Results We gathered 122 patients with recurrent GBM, 98,9% of tumors was determined as wild-type, age median was 53,36 years. All patients underwent Stupp protocol oncotherapy after prime surgery. Median of OS from prime surgery was 21 months (15.8, 29.6). The best results proved a surgery of GBM recurrency proceeding more than 6 months after diagnosis. OS2 (from redo up to the death) was 7.4 months (6.41, 11.3). 43.3% of patients recalled temozolomide chemotherapy. We confirmed positive link between OS and resection radicality, negative relations between OS and a postoperative neurologic deficits. Only limited relation was presented between OS and repeated oncotherapy. Relation to the further histologic, imunohistochemic, cytogenetic and molecular markers will be discussed. Conclusion Due to the common unfavorable outcomes of GBM therapy, out of despair, we often decided for repeated surgery. The aim of our study was avoid ineffective surgical overtreatment. The best results of surgery yield right selected recurrent GBMs. Surgery of GBM regrown during initial oncotherapy (6 months after prime surgery) presented unsatisfactory effects. Positive effect of the surgical radicality and clinic status were confirmed. Again, necessity of second-line oncotherapy has been emerged. Supported by Ministry of Health of the Czech Republic, grant nr. NV19- 04-00281 and grant nr. NU21-03-00195

Voxel-Based Morphometric MRI Postprocessing-Assisted Laser Interstitial Thermal Therapy for Focal Cortical Dysplasia-Suspected Lesions: Technique and Outcomes.

MRI-guided laser interstitial thermal therapy (MRgLITT) is a novel treatment modality for focal cortical dysplasia (FCD). However, identifying the location and extent of subtle FCD by visual analysis during MRgLITT remains challenging. To introduce voxel-based morphometric MRI postprocessing into the procedure of MRgLITT for FCD-suspected lesions and assess the complementary value of the MRI postprocessing technique for the trajectory design and thermal parameter setting of MRgLITT. Junction and normalized fluid-attenuated inversion recovery signal intensity images were used to detect the gray-white matter junction blurring and cortical fluid-attenuated inversion recovery hyperintensity, respectively. According to the 2 postprocessing images, the region of interest (ROI) for ablation was drawn. The main principle of presurgical planning is that the trajectory of the laser fiber was designed as far as possible along the long axis of the ROI while the extent of planned ablation covered the entire ROI. The subsequent intraoperative procedure was performed under the guidance of the presurgical plan. Nine patients with epilepsy with FCD-suspected lesions underwent MRgLITT with the assistance of MRI postprocessing images. Among them, 4 patients were junction positive, 2 patients were normalized fluid-attenuated inversion recovery signal intensity positive, and the remaining 3 patients were positive for both. Postsurgical MRI demonstrated that the ROIs were ablated entirely in 7 patients. Engel Ia, Ib, and IV scores were obtained at 1-year follow-up for 6, 1, and 2 patients, respectively. MRI postprocessing provides complementary information for designing the laser fiber trajectory and subsequent ablation for FCDs.

A single-institution, retrospective examination of new contrast enhancement, progression, and pseudoprogression in IDH mutant glioma.

2043 Background: IDH mutant glioma patients are followed by MRI, where new contrast enhancement (CEnew) is a hallmark of tumor progression. Interpretation of CEnew is confounded by pseudoprogression (PsP), the appearance of CEnew that spontaneously resolves on subsequent scans. PsP has been characterized in IDH wildtype patients, but is poorly understood in the IDH mutant category. This study represents an examination of the characteristics and impacts on patient survival of CEnew in IDH mutant gliomas. Methods: Of the 724 confirmed IDH mutant glioma patients treated at UCLA between 1998 and 2022, 587 were included (median follow-up = 5.23 years). Patients were excluded based on these criteria: &lt;4 MRI scans, unknown IDH status, and unknown WHO 2016 diagnosis. CEnew was first identified by direct review of images and confirmed by the radiology report. Any new enhancement appearing on the first post surgical MRI was not considered CEnew. CEnew was interpreted as progression after surgical resection indicating tumor or the re-initiation of chemotherapy or radiation and was considered PsP after the resolution of enhancement without new treatment initiation. Some PsP patients could have received bevacizumab. Kaplan-Meier survival analyses were used to examine overall survival differences between groups. Results: 327 of 587 patients developed CEnew. The incidence of CEnew was higher in Grade 4 Astrocytoma (G4 Astro) versus all other pathologies and lowest in LO (p &lt; 0.05). The Enhancement Free Survival (EFS) was shortest for G4 Astro patients (p =.002); LO patients had the longest median EFS of 2602 days (p = 0.002). The development of CEnew and presence of preoperative enhancement were both found to be negative survival prognosticators in all pathologies (p &lt; 0.05). From our analysis, 92 patients developed PsP and 177 developed progression. The median duration of a PsP spot was 244 days. PsP spots appeared earlier than progression spots (median 538 vs 1113 days, p =.001). The incidence of PsP was highest in the G4 Astro group and lowest in LO patients. Survival analysis of patients with progression versus those with PsP and progression shows PsP is associated with longer OS in the entire cohort and the LO, AO, AA, and G4 Astro groups (p &lt; 0.05). 100% of PsP patients received radiation therapy (RT). The median time from the end of RT to PsP was 209 days. Conclusions: While CEnew in IDH mutant gliomas is associated with reduced OS, poorer outcome is driven by progressors. PsP represents 28% of CEnew instances, typically occurs within 1 year of RT and have superior outcome to progressors and equivalent to of patients that do not display CEnew. [Table: see text]

Scalp HFO rates decrease after successful epilepsy surgery and are not impacted by the skull defect resulting from craniotomy

Epilepsy surgery can achieve seizure freedom in selected pediatric candidates, but reliable postsurgical predictors of seizure freedom are missing. High frequency oscillations (HFO) in scalp EEG are a new and promising biomarker of treatment response. However, it is unclear if the skull defect resulting from craniotomy interferes with HFO detection in postsurgical recordings. We considered 14 children with focal lesional epilepsy who underwent presurgical evaluation, epilepsy surgery, and postsurgical follow-up of ≥ 1 year. We identified the nearest EEG electrodes to the skull defect in the postsurgical MRI. We applied a previously validated automated HFO detector to determine HFO rates in presurgical and postsurgical EEG. Overall, HFO rates showed a positive correlation with seizure frequency (p < 0.001). HFO rates in channels over the HFO area decreased following successful epilepsy surgery, irrespective of their proximity to the skull defect (p = 0.005). HFO rates in channels outside the HFO area but near the skull defect showed no increase following surgery (p = 0.091) and did not differ from their contralateral channels (p = 0.726). Our observations show that the skull defect does not interfere with postsurgical HFO detection. This supports the notion that scalp HFO can predict postsurgical seizure freedom and thus guide therapy management in focal lesional epilepsy.

Deep learning-based automated segmentation of resection cavities on postsurgical epilepsy MRI

Accurate segmentation of surgical resection sites is critical for clinical assessments and neuroimaging research applications, including resection extent determination, predictive modeling of surgery outcome, and masking image processing near resection sites. In this study, an automated resection cavity segmentation algorithm is developed for analyzing postoperative MRI of epilepsy patients and deployed in an easy-to-use graphical user interface (GUI) that estimates remnant brain volumes, including postsurgical hippocampal remnant tissue. This retrospective study included postoperative T1-weighted MRI from 62 temporal lobe epilepsy (TLE) patients who underwent resective surgery. The resection site was manually segmented and reviewed by a neuroradiologist (JMS). A majority vote ensemble algorithm was used to segment surgical resections, using 3 U-Net convolutional neural networks trained on axial, coronal, and sagittal slices, respectively. The algorithm was trained using 5-fold cross validation, with data partitioned into training (N = 27) testing (N = 9), and validation (N = 9) sets, and evaluated on a separate held-out test set (N = 17). Algorithm performance was assessed using Dice-Sørensen coefficient (DSC), Hausdorff distance, and volume estimates. Additionally, we deploy a fully-automated, GUI-based pipeline that compares resection segmentations with preoperative imaging and reports estimates of resected brain structures. The cross-validation and held-out test median DSCs were 0.84 ± 0.08 and 0.74 ± 0.22 (median ± interquartile range) respectively, which approach inter-rater reliability between radiologists (0.84–0.86) as reported in the literature. Median 95 % Hausdorff distances were 3.6 mm and 4.0 mm respectively, indicating high segmentation boundary confidence. Automated and manual resection volume estimates were highly correlated for both cross-validation (r = 0.94, p < 0.0001) and held-out test subjects (r = 0.87, p < 0.0001). Automated and manual segmentations overlapped in all 62 subjects, indicating a low false negative rate. In control subjects (N = 40), the classifier segmented no voxels (N = 33), <50 voxels (N = 5), or a small volumes<0.5 cm3 (N = 2), indicating a low false positive rate that can be controlled via thresholding. There was strong agreement between postoperative hippocampal remnant volumes determined using automated and manual resection segmentations (r = 0.90, p < 0.0001, mean absolute error = 6.3 %), indicating that automated resection segmentations can permit quantification of postoperative brain volumes after epilepsy surgery. Applications include quantification of postoperative remnant brain volumes, correction of deformable registration, and localization of removed brain regions for network modeling.

RADT-07. DETERMINATION OF THE OPTIMAL TIME INTERVAL BETWEEN POST-OPERATIVE MRI AND CT SIMULATION FOR STEREOTACTIC RADIOSURGERY PLANNING

Abstract BACKGROUND The incidence of brain metastasis is approximately 200,000 worldwide annually. Stereotactic radiation therapy of post-operative cavity reduces local recurrence. Surgical cavity size changes significantly with 96.5% demonstrating volumetric change during post-operative period. We sought to define the optimal time interval that preserved the volumetric dimensions between the post-surgical MRI and the CT simulation used for stereotactic radiosurgery planning. METHODS Seven patients with brain metastasis that underwent surgical resection and stereotactic radiation treatment at Albany Medical Center from February 2019 to April 2020 were included in the study. A total of 8 target lesions were included. Brain lab planning system was used for contouring the target volume. A postoperative MRI within 24-48 hours after surgery was obtained. 3 patients required an additional interim MRI 16-50 days after surgery. The planning CT simulation was performed 2 days prior and up to 15 days after the post-operative/interim MRI and target volumes were compared. RESULTS The average volume of the post-surgical cavity contoured by the neurosurgeons on the post-operative/interim MRI was 15.96 cc (± 7.79 cc, range of 6.54 -24.9 cc). The average volume of the post-surgical cavity contoured by the radiation oncologists on the planning CT was 15.71 (± 7.49 cc, range of 6.53 -24.31 cc). There was no noticeable change in volume size between post-operative/interim MRI and planning CT up to the period of 15 days. LIMITATION This was a retrospective pilot study with a small sample size and patients recruited from a single center. CONCLUSION There is no change in size of the cavity volume for up to 15 days between post-operative/interim MRI and planning CT. This knowledge will help understand the optimal time interval between post-operative MRI and CT simulation for the stereotactic radiation therapy planning.