Intraoperative Magnetic Resonance Research Articles

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.

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.

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.

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.

The Value of Intraoperative Ultrasound in Brain Surgery.

Favorable clinical outcomes in adult and pediatric neurosurgical oncology generally depend on the extent of tumor resection (EOR). Maximum safe resection remains the main aim of surgery in most intracranial tumors. Despite the accuracy of intraoperative magnetic resonance imaging (iMRI) in the detection of residual intraoperatively, it is not widely implemented worldwide owing to enormous cost and technical difficulties. Over the past years, intraoperative ultrasound (IOUS) has imposed itself as a valuable and reliable intraoperative tool guiding neurosurgeons to achieve gross total resection (GTR) of intracranial tumors.Being less expensive, feasible, doesn't need a high level of training, doesn't need a special workspace, and being real time with outstanding temporal and spatial resolution; all the aforementioned advantages give a superiority for IOUS in comparison to iMRI during resection of brain tumors.In this chapter, we spot the light on the technical nuances, advanced techniques, outcomes of resection, pearls, and pitfalls of the use of IOUS during the resection of brain tumors.

Application of intraoperative ultrasound in the resection of high-grade gliomas

The incidence of gliomas is approximately 3–5/100,000, with high-grade gliomas accounting for approximately 30–40% of these tumors. Surgery is a confirmed positive factor in prolonging the survival of these patients, and a larger resection range means a longer survival time. Therefore, surgery for high-grade glioma patients should aim to maximize the extent of resection while preserving neurological function to achieve a better quality of life. There is consensus regarding the need to lengthen progression-free survival (PFS) and overall survival (OS) times. In glioma surgery, methods such as intraoperative computed tomography (ICT), intraoperative magnetic resonance imaging (IMRI), navigation, 5-aminolevulinic acid (5-ALA), and intraoperative ultrasound (IOUS) are used to achieve an expanded resection during the surgical procedure. IOUS has been increasingly used in the surgery of high-grade gliomas and various tumors due to its convenient intraoperative use, its flexible repeatability, and the relatively low cost of operating room construction. With the continuous upgrading of ultrasound equipment, IOUS has been able to better assist surgeons in achieving an increased extent of resection. This review aims to summarize the application of ultrasound in the surgery of high-grade gliomas in the past decade, its improvement in patient prognosis, and its prospects.

Intraoperative use of low-field magnetic resonance imaging for brain tumors: A systematic review

Background: Low-field magnetic resonance imaging (LF-MRI) has become a valuable tool in the diagnosis of brain tumors due to its high spatial resolution and ability to acquire images in a short amount of time. However, the use of LF-MRI for intraoperative imaging during brain tumor surgeries has not been extensively studied. The aim of this systematic review is to investigate the impact of low-field intraoperative magnetic resonance imaging (LF-IMRI) on the duration of brain tumor surgery and the extent of tumor resection. Methods: A comprehensive literature search was conducted using PubMed, Scopus, and Google Scholar from February 2000 to December 2022. The studies were selected based on the inclusion criteria and reviewed independently by two reviewers. The gathered information was organized and analyzed using Excel. Results: Our review of 21 articles found that low-field intraoperative MRI (LF-IMRI) with a field below 0.3T was used in most of the studies, specifically 15 studies used 0.15T LF-IMRI. The T1-weighted sequence was the most frequently reported, and the average scanning time was 24.26 min. The majority of the studies reported a positive impact of LF-IMRI on the extent of tumor resection, with an increase ranging from 11% to 52.5%. Notably, there were no studies describing the use of ultra-low-field (ULF) intraoperative MRI. Conclusion: The results of this systematic review will aid neurosurgeons and neuroradiologists in making informed decisions about the use of LF-MRI in brain tumor surgeries. Further, research is needed to fully understand the impact of LF-MRI in brain tumor surgeries and to optimize its use in the clinical setting. There is an opportunity to study the utility of ULF-MRI in brain tumor surgeries.

Guidelines in Practice: Minimally Invasive Surgery.

During minimally invasive surgery (MIS), surgeons create small and percutaneous incisions to access internal structures without open surgical incisions. Some MIS equipment is complex and challenging for perioperative nurses to manage. Patients also can experience life-threatening complications during MIS procedures. The updated AORN "Guideline for minimally invasive surgery" provides recommendations that perioperative nurses can use when caring for patients undergoing MIS procedures. This article provides an overview of the guideline and discusses several recommendations, including creating a safe environment in which to perform MIS procedures; using gas distension media, irrigation and fluid distension media, and computer-assisted navigation and robotics; and performing intraoperative magnetic resonance imaging in a hybrid OR. It also includes a scenario describing care of a patient undergoing a hysteroscopy. Perioperative nurses who care for patients undergoing MIS procedures should review the guideline in its entirety and apply the recommendations as applicable in their practice.

JS05.6.A CONTINUOUS DYNAMIC MAPPING OF LANGUAGE FUNCTION AND COGNITIVE CONTROL AND SPATIAL CORRELATION TO WHITE MATTER TRACTS USING INTRAOPERATIVE MRI TRACTOGRAPHY

Abstract BACKGROUND Subcortical mapping of white matter tracts (WMTs) subserving complex processes as movement, language and cognition is critical in glioma surgery. Continuous dynamic mapping (CDM) is an indispensable tool for mapping of the corticospinal tract (CST). There is, however, no widespread method for CDM of more advanced brain functions. MATERIAL AND METHODS Patients undergoing awake craniotomy for diffuse gliomas at the Oslo University Hospital with the use of neuronavigation, diffusion tensor imaging (DTI) and CDM coupled with structured evaluation as well as intraoperative magnetic resonance imaging (iMRI) were included in a retrospective analysis. Subcortical CDM was conducted when resection became close to the arcuate fasciculus (AF) and the frontal aslant tract (FAT) with clinical testing using language paradigms and Stroop task. The current was delivered through a monopolar suction probe applying a modified Taniguchi technique with short train of pulses. The spatial relationship between the stimulation response and the examined tracts was determined by measuring the shortest distance between the resection cavity and the relevant white matter tracts (WMTs) using iMRI DTI. RESULTS Twenty IDH-mutant and eight IDH wild type gliomas operated 2021-2023 were included in the analysis. Subcortical CDM of the AF and the FAT proved to be amenable as both language function and the ability to perform Stroop test were affected when the stimulation site gradually became close (&amp;lt; 1 cm) to the examined tracts. Positive stimulation response was verified by repeat challenge. The stimulation intensity was thereafter reduced in a stepwise fashion when there was a consistent hesitation in the patient’s response. Resection was continued until the tumor border was reached and not beyond the threshold of 3mA. The threshold of stimulation intensity correlated to the minimal distance from the resection cavity to the delineated WMTs. We did not observe any seizure activity induced by CDM. CONCLUSION We have experienced subcortical CDM to be a safe and reliable method, where distance to identified WMT appear to be correlated to the applied stimulation intensity.

Technical Note: Advantages of a 2-Room Intraoperative 3-Tesla Magnetic Resonance Imaging Operating Suite for Performing Laser Interstitial Thermal Therapy in Pediatric Epilepsy and Tumor Surgery

Magnetic resonance thermography-guided laser interstitial thermal therapy (LITT) provides a minimally invasive treatment option in children with central nervous system tumors or medically intractable epilepsy. However, transporting anesthetized children between an operating room (OR) and a radiologic suite creates logistical challenges. Thus we describe advantages of using a 2-room intraoperative magnetic resonance imaging (MRI) concept for LITT. Patients were pinned in a head frame that doubles as the lower part of the MRI head coil. Preoperative MRI was performed for accurate neuronavigation, after which laser fibers were stereotactically implanted. Transport between OR and MRI was achieved by sliding the top of the OR table onto a trolly. We performed 12 procedures in 11 children, mean age 7.1 years (range: 2 to 14 years). Ten children suffered from medically intractable epilepsy, and 1 child had a pilocytic midbrain astrocytoma. Two fibers were placed in 8 and 1 fiber in 4 procedures. Mean entry point and target errors were 2.8 mm and 3.4 mm, respectively. Average transfer time from OR to MRI and vice versa was 9 minutes (±1 minute, 40 seconds). Altogether, 50% of the seizure patients were seizure free (Engel grade I) at 22 months' follow-up time. One hemorrhagic event, which could be managed nonoperatively, occurred. We recorded no surgical site or intracranial infections. All LITT procedures were successfully carried out with head frame in the sterile environment. The intraoperative MRI suite proved to be advantageous for minimally invasive procedures, especially in young children resulting in short transports while maintaining high accuracy and safety.

Deep Brain Stimulation Lead Localization Variability Comparing Intraoperative MRI Versus Postoperative Computed Tomography.

Commercially available lead localization software for deep brain stimulation (DBS) often relies on postoperative computed tomography (CT) scans to define electrode positions. When cases are performed with intraoperative MRI, another imaging set exists with which to perform these localizations. To compare DBS localization error between postoperative CT scans and intraoperative MRI. A retrospective cohort of patients who underwent MRI-guided placement of DBS electrodes using the ClearPoint platform was identified. Using Brainlab Elements, postoperative CT scans were coregistered to intraoperative magnetic resonance images visualizing the ClearPoint guidance sheaths and ceramic stylets. DBS electrodes were identified in CT scans using Brainlab's lead localization tool. Trajectory and vector errors were quantified between scans for each lead in each patient. Eighty patients with a total of 157 implanted DBS electrodes were included. We observed mean trajectory and vector errors of 0.78 ± 0.44 mm (range 0.1-2.0 mm) and 1.57 ± 0.79 mm (range 0.2-4.2 mm), respectively, between postoperative CT and intraoperative MRI. There were 7 patients with CT scans collected at multiple time points. Trajectory error increased by 0.15 ± 0.42 mm ( P = .31), and vector error increased by 0.22 ± 0.53 mm ( P = .13) in the later scans. Across all scans, there was no significant association between trajectory ( P = .053) or vector ( P = .98) error and the date of CT acquisition. DBS electrodes targeting the subthalamic nucleus had significantly greater trajectory errors ( P = .02) than those targeting the globus pallidus pars internus nucleus. Commercially available software produced largely concordant lead localizations when comparing intraoperative MRIs with postoperative CT scans, with trajectory errors on average <1 mm. CT scans tend to be more comparable with intraoperative MRI in the immediate postoperative period, with increased time intervals associated with a greater magnitude of error between modalities.

Evaluating the use of intraoperative magnetic resonance imaging in paediatric brain tumour resection surgeries: a literature review.

Brain tumours are the most common solid neoplasm in children, posing a significant challenge in oncology due to the limited range of treatment. Intraoperative magnetic resonance imaging (iMRI) has recently emerged to aid surgical intervention in neurosurgery resection with the potential to delineate tumour boundaries. This narrative literature review aimed to provide an updated evaluation of the clinical implementation of iMRI in paediatric neurosurgical resection, with an emphasis on the extent of brain tumour resection, patient outcomes and its drawbacks. Databases including MEDLINE, PubMed, Scopus and Web of Science were used to investigate this topic with key terms: paediatric, brain tumour, and iMRI. Exclusion criteria included literature comprised of adult populations and the use of iMRI in neurosurgery in the absence of brain tumours. The limited body of research evaluating the clinical implementation of iMRI in paediatric cohorts has been predominantly positive. Current evidence demonstrates the potential for iMRI use to increase rates of gross total resection (GTR), assess the extent of resection, and improve patient outcomes, such as progression-free survival. Limitations regarding the use of iMRI include prolonged operation times and complications associated with head immobilisation devices. iMRI has the potential to aid in the achievement of maximal brain tumour resection in paediatric patients. Future prospective randomised controlled trials are necessary to determine the clinical significance and benefits of using iMRI during neurosurgical resection for clinical management of brain neoplasms in children.

The Impact of ioMRI on Glioblastoma Resection and Clinical Outcomes in a State-of-the-Art Neuro-Oncological Setup.

Intraoperative magnetic resonance imaging (ioMRI) aims to improve gross total resection (GTR) in glioblastoma (GBM) patients. Despite some older randomized data on safety and feasibility, ioMRI's actual impact in a modern neurosurgical setting utilizing a larger armamentarium of techniques has not been sufficiently investigated to date. We therefore aimed to analyze its effects on residual tumor, patient outcome, and progression-free survival (PFS) in GBM patients in a modern high-volume center. Patients undergoing ioMRI for resection of supratentorial GBM were enrolled between March 2018 and June 2020. ioMRI was performed in all cases at the end of resection when surgeons expected complete macroscopic tumor removal. Extent of resection (EOR) was performed by volumetric analysis, with GTR defined as an EOR ≥ 95%, respectively. Progression-free survival (PFS) was analyzed through univariate and multivariate Cox proportional regression analyses. In total, we enrolled 172 patients. Mean EOR increased from 93.9% to 98.3% (p < 0.0001) due to ioMRI, equaling an increase in GTR rates from 78.5% to 93.0% (p = 0.0002). Residual tumor volume decreased from 1.3 ± 4.2 cm3 to 0.6 ± 2.5 cm3 (p = 0.0037). Logistic regression revealed recurrent GBM as a risk factor leading to subtotal resection (STR) (odds ratio (OR) = 3.047, 95% confidence interval (CI) 1.165-7.974, p = 0.023). Additional resection after ioMRI led to equally long PFS compared to patients with complete tumor removal before ioMRI (hazard ratio (HR) = 0.898, 95%-CI 0.543-1.483, p = 0.67). ioMRI considerably reduces residual tumor volume and helps to achieve comparable PFS, even in patients with unexpected residual tumor after initial resection before ioMRI.

Improvement in Intraoperative Image Quality in Transcranial Magnetic Resonance-Guided Focused Ultrasound Surgery Using Transmitter Gain Adjustment

Introduction: Transcranial magnetic resonance-guided focused ultrasound surgery (TcMRgFUS) has the advantage of allowing immediate evaluation of therapeutic effects after each sonication and intraoperative magnetic resonance imaging (MRI) to visualize the lesion. When the image shows that the lesion has missed the planned target and the therapeutic effects are insufficient, the target of the subsequent ablation can be finely adjusted based on the image. The precision of this adjustment is determined by the image quality. However, the current intraoperative image quality with a 3.0T MRI system is insufficient for precisely detecting the lesion. Thus, we developed and validated a method for improving intraoperative image quality. Methods: Because intraoperative image quality is affected by transmitter gain (TG), we acquired T2-weighted images (T2WIs) with two types of TG: the automatically adjusted TG (auto TG) and the manually adjusted TG (manual TG). To evaluate the character of images with 2 TGs, the actual flip angle (FA), the image uniformity, and the signal-to-noise ratio (SNR) were measured using a phantom. Then, to assess the quality of intraoperative images, T2WIs with both TGs were acquired during TcMRgFUS for 5 patients. The contrast-to-noise ratio (CNR) of the lesion was retrospectively estimated. Results: The images of the phantom with the auto TG showed substantial variations between the preset and actual FAs (p p > 0.05). The total image uniformity was considerably lower with the manual TG than with the auto TG (p p p Conclusion: Regarding intraoperative T2WIs using a 3.0T MRI system during TcMRgFUS, the manual TG method improved image quality and delineated the ablative lesion more clearly than the current method with auto TG.

How to combine the use of intraoperative magnetic resonance imaging (MRI) and awake craniotomy for microsurgical resection of hemorrhagic cavernous malformation in eloquent area: a case report

BackgroundCavernous malformations are clusters of abnormal and hyalinized capillaries without interfering brain tissue. Here, we present a cavernous malformation operated under awake conditions, due to location, in an eloquent area and using intraoperative magnetic resonance imaging due to patient’s movement upon the awake phase.Case presentationWe present the pre-, per-, and postoperative course of an inferior parietal cavernous malformation, located in eloquent area, in a 27-year-old right-handed Caucasian male, presenting with intralesional hemorrhage and epilepsy. Preoperative diffusion tensor imaging has shown the cavernous malformation at the interface between the arcuate fasciculus and the inferior fronto-occipital fasciculus. We describe the microsurgical approach, combining preoperative diffusion tensor imaging, neuronavigation, awake microsurgical resection, and intraoperative magnetic resonance imaging.ConclusionComplete microsurgical en bloc resection has been performed and is feasible even in eloquent locations. Intraoperative magnetic resonance imaging was considered an important adjunct, particularly used in this case as the patient moved during the “awake" phase of the surgery and thus neuronavigation was not accurate anymore. Postoperative course was marked by a unique, generalized seizure without any adverse event. Immediate and 3 months postoperative magnetic resonance imaging confirmed the absence of any residue. Pre- and postoperative neuropsychological exams were unremarkable.

Endoscopic Endonasal Transsphenoidal Surgery for Resection of Craniopharyngioma in Pediatric Population: A Comprehensive Review of the Literature

AbstractCraniopharyngioma is a rare epithelial brain tumor which arises from the embryological remnants of Rathke's pouch—a remnant of the primitive pharynx. The proximity of this tumor to the pituitary stalk, hypothalamus, third ventricle, optic chiasm, and optic nerves, as well as the major intracranial vessels bridging this area, makes safe surgical resection challenging. Given the recent advancement in endoscopic surgical techniques and the intraoperative assistance of neuronavigation and intraoperative magnetic resonance imaging, endoscopic endonasal transsphenoidal surgery (EETS) can be an alternative to the open transcranial approaches in the management of children with craniopharyngioma who fulfill the appropriate selection criteria. The comparison between the EETS and the open transcranial approach regarding the clinical and surgical outcomes could be subject to an inherent selection bias. In this article, we reviewed the body of the literature on the role of EETS in the management of pediatric craniopharyngioma and the proper selection criteria of children with craniopharyngioma, who might be suitable candidates for tumor resection via this minimally invasive endoscopic approach. We also looked at the preoperative assessment, surgical techniques, surgical and clinical outcomes, and the possible complications of endoscopic endonasal transsphenoidal surgery.