Intraoperative Magnetic Resonance Imaging Research Articles

Intraoperative MRI without an intraoperative MRI suite: a workflow for glial tumor surgery.

Intraoperative MRI (iMRI) has emerged as a useful tool in glioma surgery to safely improve the extent of resection. However, iMRI requires a dedicated operating room (OR) with an integrated MRI scanner solely for this purpose. Due to physical or economical restraints, this may not be feasible in all centers. The aim of this study was to investigate the feasibility of using a non-dedicated MRI scanner at the radiology department for iMRI and to describe the workflow with special focus on time expenditure and surgical implications. In total, 24 patients undergoing glioma surgery were included. When the resection was deemed completed, the wound was temporarily closed, and the patient, under general anesthesia, was transferred to the radiology department for iMRI, which was performed using a dedicated protocol on 1.5 or 3T scanners. After performing iMRI the patient was returned to the OR for additional tumor resection or final wound closure. All procedural times, timestamps, and adverse events were recorded. The median time from the decision to initiate iMRI until reopening of the wound after scanning was 68 (52-104) minutes. Residual tumors were found on iMRI in 13 patients (54%). There were no adverse events during the surgeries, transfers, transportations, or iMRI-examinations. There were no wound-related complications or infections in the postoperative period or at follow-up. There were no readmissions within 30 or 90days due to any complication. Performing intraoperative MRI using an MRI located outside the OR department was feasible and safe with no adverse events. It did not require more time than previously reported data for dedicated iMRI scanners. This could be a viable alternative in centers without access to a dedicated iMRI suite.

P.142 The use of intraoperative magnetic resonance imaging for endoscopic transnasal transsphenoid surgery in children

Background: Sellar and suprasellar pediatric lesions are uncommon. Endoscopic transnasal transphenoidal surgery (ETTS) is the preferred treatment, but early post-op MRI is hindered by sphenoidal packing. This study aims to assess iMRI safety and efficacy in pediatric ETTS cases. Methods: We performed a retrospective review from Jan 01, 2015 to Dec 31, 2022, evaluating use of iMRI. We determined if the goals of the surgery (biopsy, cyst decompression, subtotal resection, gross total resection) were met, and iMRI’s influence on surgery outcomes. We examined patient age, surgery duration, length of stay, histopathology results, surgical complications, post-op MRIs within 1 month, and tumor progression/recurrence. Results: Over eight years, 20 pediatric ETTS procedures, 14 with iMRI, were conducted. Achieving goals in 13 cases, iMRI prompted extra surgery once. Two adenomas progressed, requiring a second surgery, and craniopharyngioma cases had complications, needing further interventions. Hospital stays varied (1-9 days), with a mean surgery duration of 6 hours and 47 minutes. The study underscores iMRI’s potential impact, stressing the necessity for more research in pediatric transsphenoidal surgeries. Conclusions: While intraoperative MRI in pediatric transsphenoidal surgeries may aid goal verification, this small study doesn’t conclusively demonstrate improved outcomes. Complication rates align with non-IMRI procedures, highlighting the need for further research.

ReMIND: The Brain Resection Multimodal Imaging Database

The standard of care for brain tumors is maximal safe surgical resection. Neuronavigation augments the surgeon’s ability to achieve this but loses validity as surgery progresses due to brain shift. Moreover, gliomas are often indistinguishable from surrounding healthy brain tissue. Intraoperative magnetic resonance imaging (iMRI) and ultrasound (iUS) help visualize the tumor and brain shift. iUS is faster and easier to incorporate into surgical workflows but offers a lower contrast between tumorous and healthy tissues than iMRI. With the success of data-hungry Artificial Intelligence algorithms in medical image analysis, the benefits of sharing well-curated data cannot be overstated. To this end, we provide the largest publicly available MRI and iUS database of surgically treated brain tumors, including gliomas (n = 92), metastases (n = 11), and others (n = 11). This collection contains 369 preoperative MRI series, 320 3D iUS series, 301 iMRI series, and 356 segmentations collected from 114 consecutive patients at a single institution. This database is expected to help brain shift and image analysis research and neurosurgical training in interpreting iUS and iMRI.

Appearance of intracranial cottonoids on intraoperative magnetic resonance imaging.

To our knowledge, this is a unique report of intraoperative magnetic resonance imaging (iMRI) of an intracranial cottonoid. The current literature describes images of cottonoids as a post-operative finding in the setting of an unintentionally retained foreign body; however, the iMRI images we present are important as the use of iMRI in the resection of complex tumors and epilepsy foci increases. This series of images was obtained during a craniotomy for tumor resection of a patient with dysembryoplastic neuroepithelial tumor. To determine both the degree of tumor resection and the amount of residual tumor, cottonoids were left in our patient's resection cavity and underwent iMRI. The ability to distinguish cottonoids in these images is important for intraoperative localization of resection margins and to prevent the retention of cottonoids.

Intraoperative magnetic resonance imaging in glioma surgery: a single-center experience.

To investigate the effect of intraoperative magnetic resonance imaging (Io MRI) on overall and progression-free survival (OS and PFS), on the extent of resection (EOR) in patients with glioma, and impact of the radiological diagnosis on the decision to continue the surgery when a residual mass was detected on Io MRI. The study comprised 153 glioma patients who received surgical treatment between 2013 and 2023. One-hundred twenty-five of them had Io MRI guidance during surgery. The remainder 28 patients constituted the control group who did not undergo Io MRI. All patients' age at surgery, gender, initial radiological diagnosis, primary tumor localization, EOR, last histopathological diagnosis, and the follow-up periods were recorded. The rate of tumor recurrence in Io MRI cases was significantly lower compared to the cases in the control group (p < .0001). It was decided to continue the operation in 45 Io MRI applied cases. This raised the gross total resection (GTR) rate from 33.6% to 49.6% in the Io MRI group. The frequency of GTR was significantly higher in patients with an initial radiological diagnosis of low grade glioma than those with high grade glioma. The shortest OS was seen in occipital gliomas. In this study, the convenience provided by the high-field MRI device was explored and proven both in reducing the tumor burden, increasing the PFS, and providing the surgeon with a maximal resection in the first operation.

Evaluation of the extent of resection of intracranial tumors with virtual intraoperative MRI: a case series.

Intraoperative MRI (iMRI) is the gold-standard technique for intraoperative evaluation of the extent of resection in brain tumor surgery. Unfortunately, it is currently available at only a few neurosurgical centers. A commercially available software, Virtual iMRI Cranial, provides an elastic fusion between preoperative MRI and intraoperative CT (iCT). The aim of this study was to evaluate the accuracy of this software in determining the presence of residual tumor. Virtual iMRI was performed in patients who underwent iCT after intracranial tumor resection. The results of the software in terms of presence or absence of tumor residual were then compared with postoperative MRI performed within 48 hours after surgery to evaluate the diagnostic accuracy of virtual iMRI. Sixty-six patients were included in the present study. The virtual iMRI findings were concordant with the postoperative MRI data in 35 cases (53%) in the detection of tumor residual (p = 0.006). No false-negative findings (i.e., presence of residual on postoperative MRI and absence of residual on virtual iMRI) were encountered. Virtual iMRI had a sensitivity of 1 (95% CI 0.86-1), specificity of 0.26 (95% CI 0.14-0.42), positive predictive value of 0.44 (95% CI 0.3-0.58), and negative predictive value of 1 (95% CI 0.72-1). Subgroup analysis revealed that the virtual iMRI findings were concordant with postoperative MRI findings in all cases (n = 9) of lower-grade glioma (LGG) with a sensitivity of 1 (95% CI 0.59-1) and a specificity of 1 (95% CI 0.16-1) (p = 0.003); a statistically significant association was also found for grade 4 gliomas with a sensitivity of 1 (95% CI 0.69-1) and a specificity of 0.33 (95% CI 0.08-0.7) (p = 0.046) (19 patients). No significant association was found when considering meningiomas or metastases. The commercially available virtual iMRI can predict the presence or absence of tumor residual with high sensitivity. The diagnostic accuracy of this method was higher in LGGs and much lower for meningiomas or metastases; these findings must be evaluated in prospective studies in a larger population.

297 Impact of Navigated Intraoperative Ultrasound on Brain Shift and Gross Tumor Resection

INTRODUCTION: Intraoperative imaging and neuronavigation aid in achieving maximum tumor resection. However, tissue removal during surgery can cause brain shift, which alters the relative anatomy and “de-calibrates” the standard approaches. While intraoperative MRI (iMRI) is the gold-standard to correct for brain shift, it is expensive, time-consuming, and logistically difficult. As an alternative, we investigated an approach which combines intraoperative ultrasound (ioUS) technology with preoperative imaging to allow for real-time compensation of brain shift and assessment of extent of resection (EOR). METHODS: We prospectively enrolled patients undergoing neurosurgical tumor resection at Massachusetts General Hospital beginning April 2023. Patients were registered with Brainlab Ultrasound Navigation prior to surgery. ioUS sweeps were acquired before cortex incision, mid-resection, and post-resection with bkActiv and fused to preoperative MRIs. Four points around the tumor were longitudinally tracked to assess brain shift. Data included sweep duration, image processing speed, extent of brain shift as determined by intraoperative markers, and EOR assessed from the ioUS compared with postoperative MRIs. RESULTS: Seven patients were enrolled (average age 62 ± 15, 75% male) with frontal (n = 5), temporal (n = 1), and occipital (n = 1) gliomas (n = 4) and metastases (n = 3). All patients exhibiting total resection as determined by ioUS also demonstrated total resection on post-operative MRI, evaluated independently by a neuroradiologist. The average time of scan and image processing (n = 19) was 5.7 ± 1.9 and 27.8 ± 6.5 seconds respectively. CONCLUSIONS: Navigated ioUS offers accurate and efficient assessment of EOR during surgery for tumor resections. Furthermore, when brain shift is detected, navigated ioUS can allow for compensation and continued utilization of navigation via the acquisition of a brand new, navigable, intraoperatively acquired dataset.

1248 Optimal Connectivity Map Predicts Seizure Freedom Rates After Laser Interstitial Thermal Therapy in Mesial Temporal Lobe Epilepsy

INTRODUCTION: Laser Interstitial Thermal Therapy (LiTT) is increasingly becoming a first-line surgical therapy for mesial temporal lobe epilepsy (mTLE). While promising, its seizure outcomes have also been highly variable, presumably due to an incomplete understanding of mechanisms behind LiTT. Epilepsy is a network disorder, and therefore it is crucial to account for both the effect on local destruction of epileptogenic foci, as well as global intervention of limbic circuitry, to elucidate the circuit-level mechanisms of LiTT and devise improved ablation strategies. In this study, we explore LiTT's network-level effect by investigating functional connectivity patterns and identifying optimal connectivity patterns predictive of seizure freedom. METHODS: 27 mTLE patients who underwent unilateral LiTT were classified as seizure-free (ILAE Class I) or seizure-present (ILAE Class II–VI) cohort based on one-year postoperative outcomes. Individual ablation volumes were segmented from intraoperative MRI sequences. Ablation volumes were seeded into a normative functional connectome (Brain Genomics Superstruct Project) to extract patient-specific connectivity profiles associated with ablation volumes. FC patterns were compared between the two cohorts to produce voxel-wise “t-maps” to identify local and global differences in connectivity strengths predictive of seizure freedom. RESULTS: Ten mTLE patients achieved complete seizure freedom. In seizure-free patients, right ablated volumes shared higher FC with regions such as calcarine, cuneus, and thalamic anterior pulvinar nucleus than patients with seizure presence. CONCLUSIONS: For the right-sided ablations, seizure freedom was associated with a distinctive whole-brain connectivity pattern beyond the local surgical target. Further investigation is required to explore if this pattern is specific between the two surgical sides in mTLE population.

Intraoperative MRI: A Review of Applications Across Neurosurgical Specialties.

Intraoperative MRI (iMRI) made its debut to great fanfare in the mid-1990s. However, the enthusiasm for this technology with seemingly obvious benefits for neurosurgeons has waned. We review the benefits and utility of iMRI across the field of neurosurgery and present an overview of the evidence for iMRI for multiple neurosurgical disciplines: tumor, skull base, vascular, pediatric, functional, and spine. Publications on iMRI have steadily increased since 1996, plateauing with approximately 52 publications per year since 2011. Tumor surgery, especially glioma surgery, has the most evidence for the use of iMRI contributing more than 50% of all iMRI publications, with increased rates of gross total resection in both adults and children, providing a potential survival benefit. Across multiple neurosurgical disciplines, the ability to use a multitude of unique sequences (diffusion tract imaging, diffusion-weighted imaging, magnetic resonance angiography, blood oxygenation level-dependent) allows for specialization of imaging for various types of surgery. Generally, iMRI allows for consideration of anatomic changes and real-time feedback on surgical outcomes such as extent of resection and instrument (screw, lead, electrode) placement. However, implementation of iMRI is limited by cost and feasibility, including the need for installation, shielding, and compatible tools. Evidence for iMRI use varies greatly by specialty, with the most evidence for tumor, vascular, and pediatric neurosurgery. The benefits of real-time anatomic imaging, a lack of radiation, and evaluation of surgical outcomes are limited by the cost and difficulty of iMRI integration. Nonetheless, the ability to ensure patients are provided by a maximal yet safe treatment that specifically accounts for their own anatomy and highlights why iMRI is a valuable and underutilized tool across multiple neurosurgical subspecialties.

Maximal Resection of Gliomas Adjacent to the Corticospinal Tract Using 3-T Intraoperative Magnetic Resonance Imaging

BackgroundGliomas adjacent to the corticospinal tract (CST) should be carefully resected to preserve motor function while achieving maximal surgical resection. Modern high-field intraoperative magnetic resonance imaging (iMRI) enables precise visualization of the residual tumor and intraoperative tractography. We prospectively evaluated the extent of resection and distance between the tumor resection cavity and CST using 3-T iMRI combined with motor evoked potentials (MEP) in glioma surgery. MethodParticipants comprised patients who underwent surgery for solitary supratentorial glioma located within 10 mm of the CST. All cases underwent surgery using neuronavigation with overlaid CST under MEP monitoring. The correlation between distance from CST and transcortical MEP amplitude was calculated using Spearman rank correlation. ResultsAmong the 63 patients who underwent surgery, 27 patients were enrolled in the study. Gross total resections were achieved in 26 of the 27 cases. Volumetric analysis showed the extent of resection was 98.6%. Motor function was stable or improved in 24 patients (Stable/Improved group) and deteriorated in 3 patients (Deteriorated group). All patients in the Deteriorated group showed motor deficit before surgery. Mean intraoperative minimal distance was significantly longer in the Stable/Improved group (7.3 mm) than in the Deteriorated group (1.1 mm; p < 0.05). MEP amplitude correlated with minimal distance between the resection cavity and CST (R=0.64). ConclusionsResection of gliomas adjacent to CST with a navigation system using 3-T iMRI could result in an ultimate EOR >98%. The combination of intraoperative tractography and MEP contributes to maximal removal of motor-eloquent gliomas.

Practice Patterns for Managing Recurrent Glioblastoma Multiforme

Abstract Introduction Glioblastoma multiforme (GBM) is a devastating form of cancer with a poor prognosis despite available treatments. Managing recurrent GBM remains challenging and lacks guidelines. This study aims to provide practice patterns for managing recurrent GBMs in India. Methods A panel of experts was assembled to develop practice patterns using the Delphi technique. Their responses were analyzed anonymously to ensure impartiality and generate recommendations. The statements were intended to be nonbinding and focused on promoting best practices in the field, without legal or regulatory authority. Results A total of 23 experts participated in the study, providing their opinions on various aspects of managing recurrent GBM. Consensus was achieved on individualized and multidisciplinary management as the preferred approach. Surgery in combination with other treatments was found to impact survival in patients older than 65 years, with re-surgery and adjuvant radiation and chemotherapy being the preferred options. Gadolinium-enhanced magnetic resonance imaging (MRI) brain with spectroscopy and diffusion-weighted imaging was favored. Molecular profiling was considered significant, with O6-methylguanine DNA methyltransferase methylation being most relevant. Surgery was recommended for recurrent GBMs, primarily based on Karnofsky's performance score (KPS). Surgical adjuncts such as neuronavigation and intraoperative MRI were considered valuable. Radiation therapy, specifically stereotactic radiosurgery, was recommended for selected cases, while opinions on re-chemotherapy were divided. Palliative care was deemed important. Conclusion This study presents practice patterns for managing recurrent GBM in India, providing standardized recommendations for practice. By implementing these, clinicians can make informed decisions, leading to improved patient outcomes and reduced variability in the management of recurrent GBM.

Improving advanced intraoperative MRI methods during pediatric neurosurgery.

Advanced intraoperative MR images (ioMRI) acquired during the resection of pediatric brain tumors could offer additional physiological information to preserve healthy tissue. With this work, we aimed to develop a protocol for ioMRI with increased sensitivity for arterial spin labeling (ASL) and diffusion MRI (dMRI), optimized for patient positioning regularly used in the pediatric neurosurgery setting. For ethical reasons, ASL images were acquired in healthy adult subjects that were imaged in the prone and supine position. After this, the ASL cerebral blood flow (CBF) was quantified and compared between both positions. To evaluate the impact of the RF coils setups on image quality, we compared different setups (two vs. four RF coils) by looking at T1-weighted (T1w) signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), as well as undertaking a qualitative evaluation of T1w, T2w, ASL, and dMR images. Mean ASL CBF did not differ between the surgical prone and supine positions in any of the investigated regions of interest or the whole brain. T1w SNR (gray matter: p = 0.016, 34% increase; white matter: p = 0.016, 32% increase) and CNR were higher (p = 0.016) in the four versus two RF coils setups (18.0± 1.8 vs. 13.9± 1.8). Qualitative evaluation of T1w, T2w, ASL, and dMR images resulted in acceptable to good image quality and did not differ statistically significantly between setups. Only the nonweighted diffusion image maps and corticospinal tract reconstructions yielded higher image quality and reduced susceptibility artifacts with four RF coils. Advanced ioMRI metrics were more precise with four RF coils as the standard deviation decreased. Taken together, we have investigated the practical use of advanced ioMRI during pediatric neurosurgery. We conclude that ASL CBF quantification in the surgical prone position is valid and that ASL and dMRI acquisition with two RF coils can be performed adequately for clinical use. With four versus two RF coils, the SNR of the images increases, and the sensitivity to artifacts reduces.

Two years of neurosurgical intraoperative MRI in Sweden - evaluation of use and costs.

The current shortage of radiology staff in healthcare provides a challenge for departments all over the world. This leads to more evaluation of how the radiology resources are used and a demand to use them in the most efficient way. Intraoperative MRI is one of many recent advancements in radiological practice. If radiology staff is performing intraoperative MRI at the operation ward, they may be impeded from performing other examinations at the radiology department, creating costs in terms of exams not being performed. Since this is a kind of cost whose importance is likely to increase, we have studied the practice of intraoperative MRI in Sweden. The study includes data from the first four hospitals in Sweden that installed MRI scanners adjacent to the operating theaters. In addition, we included data from Karolinska University Hospital in Solna where intraoperative MRI is carried out at the radiology department. Scanners that were moved into the operation theater and doing no or few other scans were used 11-12% of the days. Stationary scanners adjacent to the operation room were used 35-41% of the days. For scanners situated at the radiology department doing intraoperative scans interspersed among all other scans, the proportion was 92%. Our study suggests that performing exams at the radiology department rather than at several locations throughout the hospital may be an efficient approach to tackle the simultaneous trends of increasing demands for imaging and increasing staff shortages at radiology departments.

Anaesthetic considerations and challenges during awake craniotomy.

This article summarises the key anaesthetic considerations and challenges surrounding the perioperative management of a patient undergoing awake craniotomy. The main goals include patient comfort, facilitation of patient cooperation during the critical awake phase and maintenance of optimal operating conditions. These are achieved through appropriate patient selection and preparation, familiarity with the complexity of each surgical phase and potential complications that may arise, as well as maintenance of close communication among all team members. Challenges such as loss of patient cooperation, loss of airway, intraoperative nausea and vomiting, seizures, cerebral oedema, hypertension, blood loss and use of intraoperative magnetic resonance imaging are discussed. The importance of teamwork, competence, vigilance and clear management strategies for potential complications to maximise patient outcomes is also highlighted.

Effect of high-field iMRI guided resection in cerebral glioma surgery: A randomized clinical trial

BackgroundExtent of resection (EOR) in glioma contributes to longer survival. The purpose of NCT01479686 was to prove whether intraoperative magnetic resonance imaging (iMRI) increases EOR in glioma surgery and benefit survival. MethodsPatients were randomized (1:1) to receive the iMRI (n = 161) or the conventional neuronavigation (n = 160). The primary endpoint was gross total resection (GTR); secondary outcomes reported were progression-free survival (PFS), overall survival (OS), and safety. Results188 high-grade gliomas (HGGs) and 133 low-grade gliomas (LGGs) were enrolled. GTR was 83.85% in the iMRI group vs. 50.00% in the control group (P < 0.0001). In 321 patients, the median PFS (mPFS) was 65.12 months in the iMRI group and 61.01 months in the control group (P = 0.0202). For HGGs, mPFS was improved in the iMRI group (19.32 vs. 13.34 months, P = 0.0015), and a trend of superior OS compared with control was observed (29.73 vs. 25.33 months, P = 0.1233). In the predefined eloquent area HGG subgroup, mPFS, and mOS were 20.47 months and 33.58 months in the iMRI vs. 12.21 months and 21.16 months in the control group (P = 0.0098; P = 0.0375, respectively). From the exploratory analyses of HGGs, residual tumor volume (TV) < 1.0 cm3 decreased the risk of survival (mPFS: 18.99 vs. 9.43 months, P = 0.0055; mOS: 29.77 vs. 18.10 months, P = 0.0042). LGGs with preoperative (pre-OP) TV > 43.1 cm3 and postoperative (post-OP) TV > 4.6 cm3 showed worse OS (P= 0.0117) ConclusionsIt showed that iMRI significantly increased EOR and indicated survival benefits for HGGs, particularly eloquent HGGs. Residual TV in either HGGs or LGGs is a prognostic factor for survival.

Technology in anesthesiology: friend or foe?

The field of medical technology has undergone significant advancements over the years, from the use of ancient scalpels, forceps, and sutures to complex devices like intraoperative MRI suites, artificial intelligence-enabled monitors, and robotic surgical systems. These advancements have had a profound impact on the way we diagnose, treat, and prevent diseases, and have significantly improved the quality of life for millions of people around the world. As we move forward, it is important to reflect on the direction of medical technology and consider the potential risks and benefits of new advancements. We must also ensure that these technologies are accessible to all and that they are used ethically and responsibly. There is still much to be discovered and developed in the field of medical technology, and it is up to us to ensure that we are moving in a positive direction that benefits everyone.

Intraoperative Magnetic Resonance Imaging in Brain Glioma Surgery Using Low-field system. Presentation of the First Twenty-eight Procedures

Background: Imaging systems placed into the operating theatre is becoming a standard practice in glioma resection surgery. Aim: To evaluate feasibility, safety, and utility of an intraoperative open low-field magnetic resonance imaging (iMRI) to assess the extent of glioma resection. Methods: Study population sample included 28 patients undergoing first time surgical resection for brain gliomas. All patients underwent preoperative and postoperative high-field MRI scans, and one to four intraoperative MRI acquisitions, using a side-opening 0.25 T MRI system. Pre- and postoperative MRI scans were assessed to measure volumetric changes and the extent of resection. Surgical timing was also registered. Results: n=28 patients (19 men and 9 women, range: 6 - 71 years), underwent microsurgical resection of brain glioma for the first time (18 high-grade and 10 low-grade gliomas). Postoperative MRI indicated that gross total resection (&gt;99%) was achieved in 23/28 (82%), subtotal resection (90-99%) in 4/28 (14%) patients; in the latter, residual tumor volume ranges between 0.5 and 8.2 cm3; and partial resection (&lt;90%) in 1/28 (4%). Three patients (10.7%) experienced worsening of neurological symptoms (only one permanent). The average time required for each imaging session was 12 minutes. Conclusion and Relevance: Intraoperative low-field MRI-guided resections maximizes the extent of glioma resections, without significant interferences with surgical and anesthesiologic procedures and without excessive prolongation of the surgery, playing a relevant role in patient survival and quality of life.

Navigated intraoperative ultrasound in neuro-oncology: volumetric accuracy and correlation with high-field MRI.

The use of intraoperative techniques to detect residual tumors has recently become increasingly important. Intraoperative MRI has long been considered the gold standard; however, it is not widely used because of high equipment costs and long acquisition times. Consequently, real-time intraoperative ultrasound (ioUS), which is much less expensive than MRI, has gained popularity. The aim of the present study was to evaluate the capacity of ioUS to accurately determine the primary tumor volume and detect residual tumors. A prospective study of adult patients who underwent surgery for intra-axial brain tumors between November 2017 and October 2020 was performed. Navigated intraoperative ultrasound (nioUS) of the brain was used to guide tumor resection and to detect the presence of residual disease. Both convex (5-8 MHz) and linear array (6-13 MHz) probes were used. Tumor volume and residual disease were measured with nioUS and compared with MR images. A linear regression model based on a machine learning pipeline and a Bland-Altman analysis were used to assess the accuracy of nioUS versus MRI. Eighty patients (35 females and 45 males) were included. The mean age was 58 years (range 25-80 years). A total of 88 lesions were evaluated; there were 64 (73%) gliomas, 19 (21.6%) metastases, and 5 (5.7%) other tumors, mostly located in the frontal (41%) and temporal (27%) lobes. Most of the tumors (75%) were perfectly visible on ioUS (grade 3, Mair grading system), except for those located in the insular lobe (grade 2). The regression model showed a nearly perfect correlation (R2 = 0.97, p < 0.001) between preoperative tumor volumes from both MRI and nioUS. Ultrasonographic visibility significantly influenced this correlation, which was stronger for highly visible (grade 3) tumors (p = 0.01). For residual tumors, the correlation between postoperative MRI and nioUS was weaker (R2 = 0.78, p < 0.001) but statistically significant. The Bland-Altman analysis showed minimal bias between the two techniques for pre- and postoperative scenarios, with statistically significant results for the preoperative concordance. The authors' findings show that most brain tumors are well delineated by nioUS and almost perfectly correlated with MRI-based measurements both pre- and postoperatively. These data support the hypothesis that nioUS is a reliable intraoperative technique that can be used for real-time monitoring of brain tumor resections and to perform volumetric analysis of residual disease.

The Father of Wisdom: "The Influence of Surgical Experience on Overall Survival in Patients with Malignant Gliomas".

The role of surgery in the management of malignant gliomas has been feverishly deliberated after the publication of the first expansive case series, the last two decades reinvigorating the discussion regarding the value of total removal in improving survivability. Despite numerous technologies being implemented to increase the resection rates of malignant gliomas, the role of surgical experience has been largely overlooked. This article aims to discuss the importance of a single surgeon's experience in treating high-grade gliomas over a period of 20years. In order to demonstrate the role of surgical experience, we divided the patients operated by a single neurosurgeon into two distinct intervals: between 2000 and 2009 and between 2012 and 2020, respectively. Only cases with subsequent adjuvant radio-chemotherapy were included. For objective reasons, no technologies that could assist the extent of resection (EOR) such as intraoperative MRI (iMRI) or 5-ALA could be used in the country of our study. Gross total resection was the main goal whenever possible, whereas subtotal removal was defined as a clear remnant on contrasted MRI or CT performed 24-48h postoperatively. Using the Kaplan-Meier method, we analyzed the survival and disease-free interval of our patients according to age, pathology, and degree of resection. In the 20-year interval of our retrospective study, the main author (ISF) operated 1591 cases of gliomas in a total of 1878 surgeries, including recurrences. The number of high-grade glioma (HGG) patients was 909 (57.10%), 495 of which were male (54.5%) and 414 (45.5%) female. The mean age of the HGG population was 51.9years. The most common type of HGG subtype were glioblastomas with a total number 620 cases (68.2%). Regarding overall survival (OS), average survival at 12months was better by 1.6%, and 12.1% improved at 18months and 17.8% longer at 24months in the 2012-2020 interval. The mean OS in the earlier interval was 11.00months compared to the second when it reached 13.441months (CI, 12.642-14.24). Surgical treatment represents a critical step in the multimodal treatment of malignant gliomas. According to our results, surgical experience improves not only overall survival in a manner equivalent to adjuvant chemotherapy but also the quality of life. As such, a special qualification in neurooncology may prove necessary in offering these patients a second chance at life.

Acute toxicity outcomes from salvage high-dose-rate brachytherapy for locally recurrent prostate cancer after prior radiotherapy.

Isolated intra-prostatic recurrence of prostate adenocarcinoma after definitive radiotherapy presents a challenging clinical scenario. Salvage options require specialized expertise and pose risks of harm. This study aimed to present the acute toxicity results from using salvage high-dose-rate brachytherapy (sHDR-BT) as treatment in locally recurrent prostate cancer cases. Seventeen consecutive patients treated with sHDR-BT between 2019 and 2022 were evaluated retrospectively. Eligible patients had to have received curative intent prostate radiotherapy previously, and showed evidence of new biochemical failure. Evaluation with American Urological Association (AUA) and Common Terminology Criteria for Adverse Events (CTCAE) symptom assessments were performed for each case. The median (inter-quartile range) age prior to salvage treatment was 68 (66-74) years. The median post-sHDR-BT follow-up time was 20 (13-24) months. At baseline prior to sHDR-BT, 8 (47%) patients had significant lower urinary tract symptoms. The median AUA score prior to sHDR-BT was 7 (3-18). Three (18%) patients reported irregular bowel function and 2 (12%) reported hematochezia prior to sHDR-BT. One-month post-treatment, the median AUA score was 13 (8-21, p = 0.21). Using CTCAE scoring, there were no cases of grade 2+ bowel or rectal toxicity, and no cases of grade 3+ urinary toxicity. Reported grade 2 urinary toxicities included 10 (59%) cases of bladder spasms, 2 (12%) cases of incontinence, 1 (6%) urinary obstruction, and 4 (24%) reports of urinary urgency. All these adverse events were temporary. This study adds to the existing literature by demonstrating that the acute toxicity profile of sHDR-BT is acceptable even without intra-operative magnetic resonance (MR) guidance or image registration. Further study is ongoing to determine long-term efficacy and toxicity of treatment.