Resection of pediatric intracerebral tumors with the aid of intraoperative real-time 3-D ultrasound

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.

Enhancing the Reliability of Intraoperative Ultrasound in Pediatric Space-Occupying Brain Lesions

INTRODUCTION

Intraoperative ultrasound (IOUS) may aid the resection of space-occupying brain lesions, though technical limits may hinder its reliability.

METHODS

IOUS (MyLabTwice^®, Esaote, Italy) with a microconvex probe was utilized in 45 consecutive cases of children with supratentorial space-occupying lesions aiming to localize the lesion (pre-IOUS) and evaluate the extent of resection (EOR, post-IOUS). Technical limits were carefully assessed, and strategies to enhance the reliability of real-time imaging were accordingly proposed.

RESULTS

Pre-IOUS allowed us to localize the lesion accurately in all of the cases (16 low-grade gliomas, 12 high-grade gliomas, eight gangliogliomas, seven dysembryoplastic neuroepithelial tumors, five cavernomas, and five other lesions, namely two focal cortical dysplasias, one meningioma, one subependymal giant cell astrocytoma, and one histiocytosis). In 10 deeply located lesions, IOUS with hyperechoic marker, eventually coupled with neuronavigation, was useful to plan the surgical route. In seven cases, the administration of contrast ensured a better definition of the vascular pattern of the tumor. Post-IOUS allowed the evaluation of EOR reliably in small lesions (<2 cm). In large lesions (>2 cm) assessing EOR is hindered by the collapsed surgical cavity, especially when the ventricular system is opened, and by artifacts that may simulate or hide residual tumors. The main strategies to overcome the former limit are inflation of the surgical cavity through pressure irrigation while insonating, and closure of the ventricular opening with Gelfoam before insonating. The strategies to overcome the latter are avoiding the use of hemostatic agents before IOUS and insonating through normal adjacent brain instead of corticotomy. These technical nuances enhanced the reliability of post-IOUS, with a total concordance to postoperative MRI. Indeed, the surgical plan was changed in about 30% of cases, as IOUS showed a residual tumor that was left behind.

CONCLUSION

IOUS ensures reliable real-time imaging in the surgery of space-occupying brain lesions. Limits may be overcome with technical nuances and proper training.

Intraoperative MRI versus intraoperative ultrasound in pediatric brain tumor surgery: is expensive better than cheap? A review of the literature

PURPOSE

The extent of brain tumor resection (EOR) is a fundamental prognostic factor in pediatric neuro-oncology in association with the histology. In general, resection aims at gross total resection (GTR). Intraoperative imaging like intraoperative US (iOUS) and MRI have been developed in order to find any tumoral remnant but with different costs. Aim of our work is to review the current literature in order to better understand the differences between costs and efficacy of MRI and iOUS to evaluate tumor remnants intraoperatively.

METHODS

We reviewed the existing literature on PubMed until 31st December 2021 including the sequential keywords "intraoperative ultrasound and pediatric brain tumors", "iUS and pediatric brain tumors", "intraoperative magnetic resonance AND pediatric brain tumors", and "intraoperative MRI AND pediatric brain tumors.

RESULTS

A total of 300 papers were screened through analysis of title and abstract; 254 were excluded. After selection, a total of 23 articles were used for this systematic review. Among the 929 patients described, a total of 349(38%) of the cases required an additional resection after an iMRI scan. GTR was measured on 794 patients (data of 69 patients lost), and it was achieved in 552(70%) patients. In case of iOUS, GTR was estimated in 291 out of 379 (77%) cases. This finding was confirmed at the post-operative MRI in 256(68%) cases.

CONCLUSIONS

The analysis of the available literature demonstrates that expensive equipment does not always mean better. In fact, for the majority of pediatric brain tumors, iOUS is comparable to iMRI in estimating the EOR.

Navigated Intraoperative 2-Dimensional Ultrasound in High-Grade Glioma Surgery: Impact on Extent of Resection and Patient Outcome

BACKGROUND

Maximizing extent of resection (EOR) and reducing residual tumor volume (RTV) while preserving neurological functions is the main goal in the surgical treatment of gliomas. Navigated intraoperative ultrasound (N-ioUS) combining the advantages of ultrasound and conventional neuronavigation (NN) allows for overcoming the limitations of the latter.

OBJECTIVE

To evaluate the impact of real-time NN combining ioUS and preoperative magnetic resonance imaging (MRI) on maximizing EOR in glioma surgery compared to standard NN.

METHODS

We retrospectively reviewed a series of 60 cases operated on for supratentorial gliomas: 31 operated under the guidance of N-ioUS and 29 resected with standard NN. Age, location of the tumor, pre- and postoperative Karnofsky Performance Status (KPS), EOR, RTV, and, if any, postoperative complications were evaluated.

RESULTS

The rate of gross total resection (GTR) in NN group was 44.8% vs 61.2% in N-ioUS group. The rate of RTV > 1 cm3 for glioblastomas was significantly lower for the N-ioUS group (P < .01). In 13/31 (42%), RTV was detected at the end of surgery with N-ioUS. In 8 of 13 cases, (25.8% of the cohort) surgeons continued with the operation until complete resection. Specificity was greater in N-ioUS (42% vs 31%) and negative predictive value (73% vs 54%). At discharge, the difference between pre- and postoperative KPS was significantly higher for the N-ioUS (P < .01).

CONCLUSION

The use of an N-ioUS-based real-time has been beneficial for resection in noneloquent high-grade glioma in terms of both EOR and neurological outcome, compared to standard NN. N-ioUS has proven usefulness in detecting RTV > 1 cm3.

Machine Vision for Real-Time Intraoperative Anatomic Guidance: A Proof-of-Concept Study in Endoscopic Pituitary Surgery

BACKGROUND

Current intraoperative orientation methods either rely on preoperative imaging, are resource-intensive to implement, or difficult to interpret. Real-time, reliable anatomic recognition would constitute another strong pillar on which neurosurgeons could rest for intraoperative orientation.

OBJECTIVE

To assess the feasibility of machine vision algorithms to identify anatomic structures using only the endoscopic camera without prior explicit anatomo-topographic knowledge in a proof-of-concept study.

METHODS

We developed and validated a deep learning algorithm to detect the nasal septum, the middle turbinate, and the inferior turbinate during endoscopic endonasal approaches based on endoscopy videos from 23 different patients. The model was trained in a weakly supervised manner on 18 and validated on 5 patients. Performance was compared against a baseline consisting of the average positions of the training ground truth labels using a semiquantitative 3-tiered system.

RESULTS

We used 367 images extracted from the videos of 18 patients for training, as well as 182 test images extracted from the videos of another 5 patients for testing the fully developed model. The prototype machine vision algorithm was able to identify the 3 endonasal structures qualitatively well. Compared to the baseline model based on location priors, the algorithm demonstrated slightly but statistically significantly (P < .001) improved annotation performance.

CONCLUSION

Automated recognition of anatomic structures in endoscopic videos by means of a machine vision model using only the endoscopic camera without prior explicit anatomo-topographic knowledge is feasible. This proof of concept encourages further development of fully automated software for real-time intraoperative anatomic guidance during surgery.

Intraoperative Ultrasound-Assisted Extent of Resection Assessment in Pediatric Neurosurgical Oncology

Central nervous system tumors represent the most frequent solid malignancy in the pediatric population. Maximal safe surgical resection is a mainstay of treatment, with significant prognostic impact for the majority of histotypes. Intraoperative ultrasound (ioUS) is a widely available tool in neurosurgery to assist in intracerebral disease resection. Despite technical caveats, preliminary experiences suggest a satisfactory predictive ability, when compared to magnetic resonance imaging (MRI) studies. Most of the available evidence on ioUS applications in brain tumors derive from adult series, a scenario that might not be representative of the pediatric population. We present our preliminary experience comparing ioUS-assisted resection assessment to early post-operative MRI findings in 154 consecutive brain tumor resections at our pediatric neurosurgical unit. A high concordance was observed between ioUS and post-operative MRI. Overall ioUS demonstrated a positive predictive value of 98%, a negative predictive value of 92% in assessing the presence of tumor residue compared to postoperative MRI. Overall, sensibility and specificity were 86% and 99%, respectively. On a multivariate analysis, the only variable significantly associated to unexpected tumor residue on postoperative MRI was histology. Tumor location, patient positioning during surgery, age and initial tumor volume were not significantly associated with ioUS predictive ability. Our data suggest a very good predictive value of ioUS in brain tumor resective procedures in children. Low-grade glioma, high-grade glioma and craniopharyngioma might represent a setting deserving specific endeavours in order to improve intraoperative extent of resection assessment ability.

The role of intraoperative ultrasound in gross total resection of brain mass lesions and outcome

Background

Surgical resection of brain mass lesion mandates safety and the best outcome for the patient.

Objectives

The aim of this study was the evaluation of intraoperative ultrasound (IOUS) in gross total resection of brain mass lesions and patients’ safety in comparison to conventional surgery.

Materials and methods

In total, 632 patients were operated for brain mass lesion resection at Neurosurgery Department, Zagazig University Hospitals, during the period from January 2011 to October 2018 and divided randomly into two groups, IOUS group and conventional group, for the detection value of IOUS in resection, safety, and outcome after 3 months follow-up.

Results

The IOUS group showed statistically significant gross total resection regardless to pathology, location, size, age, and sex in favor of IOUS use, and also, there were significantly less complications and better outcome after 3 months follow-up with the IOUS group. Significantly better outcome was found with gross total resection in total surgeries.

Conclusions

The use of IOUS during brain mass lesion surgery is safe and can assist the surgeon in gross total resection with better outcome.

Reliability of intraoperative ultrasound in detecting tumor residual after brain diffuse glioma surgery: a systematic review and meta-analysis

Intraoperative ultrasonography (iUS) is considered an accurate, safe, and cost-effective tool to estimate the extent of resection of both high-grade (HGG) and low-grade (DLGG) diffuse gliomas (DGs). However, it is currently missing an evidence-based assessment of iUS diagnostic accuracy in DGs surgery. The objective of review is to perform a systematic review and meta-analysis of the diagnostic performance of iUS in detecting tumor residue after DGs resection. A comprehensive literature search for studies published through October 2018 was performed according to PRISMA-DTA and STARD 2015 guidelines, using the following algorithm: ("ultrasound" OR "ultrasonography" OR "ultra-so*" OR "echo*" OR "eco*") AND ("brain" OR "nervous") AND ("tumor" OR "tumour" OR "lesion" OR "mass" OR "glio*" OR "GBM") AND ("surgery" OR "surgical" OR "microsurg*" OR "neurosurg*"). Pooled sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-), and diagnostic odds ratio (DOR) of iUS in DGs were calculated. A subgroup analysis for HGGs and DLGGs was also conducted. Thirteen studies were included in the systematic review (665 DGs). Ten articles (409 DGs) were selected for the meta-analysis with the following results: sensitivity 72.2%, specificity 93.5%, LR- 0.29, LR+ 3, and DOR 9.67. Heterogeneity among studies was non-significant. Subgroup analysis demonstrates a better diagnostic performance of iUS for DLGGs compared with HGGs. iUS is an effective technique in assessing DGs resection. No significant differences are seen regarding iUS modality and transducer characteristics. Its diagnostic performance is higher in DLGGs than HGGs and could be worsened by previous treatments, surgical artifacts, and small tumor residue volumes.

Efficacy of intraoperative ultrasonography in neurosurgical tumor resection

OBJECTIVE Intraoperative ultrasonography (IOUS) is a widely accessible imaging modality that provides real-time surgical guidance with minimal identified risk or additional operative time. A recent study by the authors found a strong correlation between IOUS and postoperative MRI findings when evaluating the extent of tumor resection, suggesting that IOUS might have significant clinical implications. The objective of this study was to expand on results from the previous study in order to provide more evidence on the usage of IOUS in the determination of gross-total resection (GTR) in both adult and pediatric patients with brain tumors. METHODS This study consisted of a retrospective review of adult and pediatric neurosurgical patients who were treated at Albany Medical Center between August 2009 and March 2016 for a tumor of the brain. All patients were treated with IOUS and then underwent postoperative MRI (with and without contrast) within 1 week of surgery. RESULTS A total of 260 patients (55% of whom were males) met inclusion criteria for the study (age range 3 months to 84 years). IOUS results showed a strong association with postoperative MRI results (φ = 0.693, p < 0.001) and an 81% intended GTR rate. In cases in which GTR was pursued, 19% had false-negative results. IOUS was able to accurately identify residual tumor in 100% of subtotal resection cases where resection was stopped due to invasion of tumor into eloquent locations. Cases involving gliomas had a 75% intended GTR rate and a 25% false-negative rate. Cases involving metastatic tumors had an 87% intended GTR rate and a 13% false-negative rate. The sensitivity, specificity, negative predictive value, and positive predictive value are reported for IOUS in all included tumor pathologies, glioma cases, and metastatic tumor cases, respectively. CONCLUSIONS The use of IOUS may allow for a reliable imaging modality to achieve a more successful GTR of brain tumors in both adult and pediatric neurosurgical patients. When attempting GTR, the authors demonstrated an 81% GTR rate. The authors also report false-negative IOUS results in 19% of attempted GTR cases. The authors support the use of IOUS in both adult and pediatric CNS tumor surgery to improve surgical outcomes. However, further studies are warranted to address existing limitations with its use to further improve its efficacy and better define its role as an intraoperative imaging tool.

Long-term Survivors of Childhood Brain Tumors: Impact on General Health and Quality of Life

PURPOSE OF REVIEW

We review and summarize the key issues affecting general health and quality of life (QOL) of pediatric long-term survivors of brain tumors.

RECENT FINDINGS

Long-term survivors of brain tumors are at risk of considerable late morbidity and mortality. Lengthening survival in brain tumors has highlighted the deep impact of tumor and its treatment on the physical, psychological, functional, and social health and QOL of these survivors. Evolution in tumor therapy including surgery, radiotherapy, and systemic therapies, etc., has the potential to mitigate this impact to some extent. Sensitization of health staff, policy makers, and the primary designers of clinical trials towards integration of QOL end points while measuring survival in brain tumor patients is the need of the hour. New developments in tumor therapeutics must not only provide quantitative gain but also improve the quality of survival in these long-term survivors. While majority of the issues presented pertain to survivorship in pediatric brain tumor population, similar challenges are likely to exist in young adults surviving brain tumors as well.

Resection of Pediatric Brain Tumors: Intraoperative Ultrasound Revisited

Background:

Extent of resection is a very important prognostic marker in most pediatric brain tumors. Intraoperative imaging facilitates resection control. Intraoperative ultrasound (IOUS) is a cost-effective alternative to intraoperative magnetic resonance, but scant literature addresses its utility in this context.

Methods:

We retrospectively reviewed all pediatric brain tumors operated at our center using navigated three-dimensional ultrasound (US). The utility of the US in resection control was recorded and extent of resection evaluated.

Results:

IOUS was used in 20 cases (3 for frameless biopsy and 17 for tumor resection control). It was 100% accurate in localizing all tumors and yielded 100% diagnosis in the biopsy cases. Technical limitations precluded its use in 2 of the 17 cases of tumor resection. In the remaining 15, it correctly predicted the residual tumor status in 13 cases (87%). A gross total resection was achieved overall in 12 cases (80%) with postoperative morbidity in only one case.

Conclusions:

IOUS is a useful tool to localize intracranial tumors and guide the resection reliably. Widespread use can improve its applicability and make it an effective intraoperative imaging tool in pediatric brain tumors.

Correlation between intraoperative ultrasound and postoperative MRI in pediatric tumor surgery

OBJECTIVE Malignant disease of the CNS is the primary etiology for deaths resulting from cancer in the pediatric population. It has been well documented that outcomes of pediatric neurosurgery rely on the extent of tumor resection. Therefore, techniques that improve surgical results have significant clinical implications. Intraoperative ultrasound (IOUS) offers real-time surgical guidance and a more accurate means for detecting residual tumor that is inconspicuous to the naked eye. The objective of this study was to evaluate the correlation of extent of resection between IOUS and postoperative MRI. The authors measured the correlation of extent of resection, negative predictive value, and sensitivity of IOUS and compared them with those of MRI. METHODS This study consisted of a retrospective review of the medical charts of all pediatric patients who underwent neurosurgical treatment of a tumor between August 2009 and July 2015 at Albany Medical Center. Included were patients who were aged ≤ 21 years, who underwent brain or spinal tumor resection, for whom IOUS was used during the tumor resection, and for whom postoperative MRI (with and without contrast) was performed within 1 week of surgery. RESULTS Sixty-two patients met inclusion criteria for the study (33 males, mean age 10.0 years). The IOUS results very significantly correlated with postoperative MRI results (φ = 0.726; p = 0.000000011; negative predictive value 86.3% [95% CI 73.7%-94.3%]). These results exemplify a 71% overall gross-total resection rate and 80% intended gross-total resection rate with the use of IOUS (i.e., excluding cases performed only for debulking purposes). CONCLUSIONS The use of IOUS may play an important role in achieving a greater extent of resection by providing real-time information on tumor volume and location in the setting of brain shift throughout the course of an operation. The authors support the use of IOUS in pediatric CNS tumor surgery to improve clinical outcomes at low cost with minimal additional operating-room time and no identified additional risk.

Neurosurgical tools to extend tumor resection in pediatric hemispheric low-grade gliomas: iMRI

INTRODUCTION

The treatment of low-grade gliomas (LGGs) in pediatric age is still controversial. However, most authors report longer life expectancy in case of completely removed cerebral gliomas. Intraoperative magnetic resonance imaging (iMRI) is increasingly utilized in the surgical management of intra-axial tumor in adults following the demonstration of its effectiveness. In this article, we analyze the management of LGG using iMRI focusing on its impact on resection rate and its limits in the pediatric population.

METHODS

We performed review of the literature regarding the treatment of LGG using iMRI focusing on its impact on resection rate and its limits in the pediatric population. Some exemplary cases are also described.

RESULTS

Intraoperative MRI allowed extension of tumor resection after the depiction of residual tumor at the intraoperative imaging control from 21 to 52 % of the cases in the published series. Moreover, the early reoperation rate was significantly lower when compared with the population treated without this tool (0 % vs 7-14 %). Some technical difficulties have been described in literature regarding the use of iMRI in the pediatric population especially for positioning due to the structure of the headrest coil designed for adult patients.

CONCLUSION

The analysis of the literature and our own experience with iMRI in children indicates significant advantages in the resection of LGG offered by the technique. All these advantages are obtained without elongation of the surgical times or increased risk for complications, namely infection. The main limit for a wider diffusion of iMRI for the pediatric neurosurgical center is the cost required, for acquisition of the system, especially for high-field magnet, and the environmental and organizational changes necessary for its use.

Applications of Ultrasound in the Resection of Brain Tumors

Neurosurgery makes use of preoperative imaging to visualize pathology, inform surgical planning, and evaluate the safety of selected approaches. The utility of preoperative imaging for neuronavigation, however, is diminished by the well-characterized phenomenon of brain shift, in which the brain deforms intraoperatively as a result of craniotomy, swelling, gravity, tumor resection, cerebrospinal fluid (CSF) drainage, and many other factors. As such, there is a need for updated intraoperative information that accurately reflects intraoperative conditions. Since 1982, intraoperative ultrasound has allowed neurosurgeons to craft and update operative plans without ionizing radiation exposure or major workflow interruption. Continued evolution of ultrasound technology since its introduction has resulted in superior imaging quality, smaller probes, and more seamless integration with neuronavigation systems. Furthermore, the introduction of related imaging modalities, such as 3-dimensional ultrasound, contrast-enhanced ultrasound, high-frequency ultrasound, and ultrasound elastography, has dramatically expanded the options available to the neurosurgeon intraoperatively. In the context of these advances, we review the current state, potential, and challenges of intraoperative ultrasound for brain tumor resection. We begin by evaluating these ultrasound technologies and their relative advantages and disadvantages. We then review three specific applications of these ultrasound technologies to brain tumor resection: (1) intraoperative navigation, (2) assessment of extent of resection, and (3) brain shift monitoring and compensation. We conclude by identifying opportunities for future directions in the development of ultrasound technologies.

High Precision Imaging of Microscopic Spread of Glioblastoma with a Targeted Ultrasensitive SERRS Molecular Imaging Probe

The dismal prognosis of patients with malignant brain tumors such as glioblastoma multiforme (GBM) is attributed mostly to their diffuse growth pattern and early microscopic tumor spread to distant regions of the brain. Because the microscopic tumor foci cannot be visualized with current imaging modalities, it remains impossible to direct treatments optimally. Here we explored the ability of integrin-targeted surface-enhanced resonance Raman spectroscopy (SERRS) nanoparticles to depict the true tumor extent in a GBM mouse model that closely mimics the pathology in humans. The recently developed SERRS-nanoparticles have a sensitivity of detection in the femtomolar range. An RGD-peptide-conjugated version for integrin-targeting (RGD-SERRS) was compared directly to its non-targeted RAD-SERRS control in the same mice via Raman multiplexing. Pre-blocking with RGD peptide before injection of RGD-SERRS nanoparticles was used to verify the specificity of integrin-targeting. In contrast to the current belief that the enhanced permeability and retention (EPR) effect results in a baseline uptake of nanoparticles regardless of their surface chemistry, integrin-targeting was shown to be highly specific, with markedly lower accumulation after pre-blocking. While the non-targeted SERRS particles enabled delineation of the main tumor, the RGD-SERRS nanoparticles afforded a major improvement in visualization of the true extent and the diffuse margins of the main tumor. This included the detection of unexpected tumor areas distant to the main tumor, tracks of migrating cells of 2-3 cells in diameter, and even isolated distant tumor cell clusters of less than 5 cells. This Raman spectroscopy-based nanoparticle-imaging technology holds promise to allow high precision visualization of the true extent of malignant brain tumors.

The influence of intraoperative resection control modalities on survival following gross total resection of glioblastoma

The purpose of the present study is to analyze the impact of intraoperative resection control modalities on overall survival (OS) and progression-free survival (PFS) following gross total resection (GTR) of glioblastoma. We analyzed data of 76 glioblastoma patients (30f, mean age 57.4 ± 11.6 years) operated at our institution between 2009 and 2012. Patients were only included if GTR was achieved as judged by early postoperative high-field MRI. Intraoperative technical resection control modalities comprised intraoperative ultrasound (ioUS, n = 48), intraoperative low-field MRI (ioMRI, n = 22), and a control group without either modality (n = 11). The primary endpoint of our study was OS, and the secondary endpoint was PFS-both analyzed in Kaplan-Meier plots and Cox proportional hazards models. Median OS in all 76 glioblastoma patients after GTR was 20.4 months (95 % confidence interval (CI) 18.5-29.0)-median OS in patients where GTR was achieved using ioUS was prolonged (21.9 months) compared to those without ioUS usage (18.8 months). A multiple Cox model adjusting for age, preop Karnofsky performance status, tumor volume, and the use of 5-aminolevulinic acid showed a beneficial effect of ioUS use, and the estimated hazard ratio was 0.63 (95 % CI 0.31-1.2, p = 0.18) in favor of ioUS, however not reaching statistical significance. A similar effect was found for PFS (hazard ratio 0.59, p = 0.072). GTR of glioblastoma performed with ioUS guidance was associated with prolonged OS and PFS. IoUS should be compared to other resection control devices in larger patient cohorts.

Intraoperative ultrasound in pediatric brain tumors: does the surgeon get it right?

PURPOSE

Intraoperative ultrasound (iUS) is a valuable tool-inexpensive, adds minimal surgical time, and involves minimal risk. The diagnostic predictive value of iUS is not fully characterized in Pediatric Neurosurgery. Our objective is to determine if surgeon-completed iUS has good concordance with post-operative MRI in estimating extent of surgical resection (EOR) of pediatric brain tumors.

METHODS

We reviewed charts of all pediatric brain tumor resections (single institution 2006-2013). Those with iUS and postoperative imaging (<1 week) were included. The surgeon's estimation of the EOR based on iUS and the post-operative neuroimaging results (gold standard) were collected, as well as information about the patients/tumors.

RESULTS

Two hundred two resections were reviewed and 58 cases were included. Twenty-six of the excluded cases utilized iUS but did not have EOR indicated. The concordance of interpretation between iUS and post-operative MRI was 98.3%. Of 43 cases where iUS suggested gross total resection, 42 were confirmed on MRI (negative predictive value (NPV), 98%). All 15 cases where iUS suggested subtotal resection were confirmed on MRI (positive predictive value (PPV), 100 %). Agreement between iUS and post-operative imaging had an overall Kappa score of 0.956, signifying almost perfect agreement.

CONCLUSION

The results from this study suggest that iUS is reliable with both residual tumor (PPV-100%) and when it suggests no residual (NPV-98%) in tumors that are easily identifiable on iUS. However, tumors that were difficult to visualize on iUS were potentially excluded, and therefore, these results should not be extrapolated for all brain tumor types.

Strategies to improve the quality of survival for childhood brain tumour survivors

BACKGROUND

Tumours of the central nervous system (CNS) are the most frequent solid tumours and the second most frequent type of cancer in children and adolescents. Overall survival has continuously improved in Germany, since an increasing number of patients have been treated according to standardised, multicentre, multimodal treatment recommendations, trials of the German Paediatric Brain Tumour Consortium (HIT-Network) or the International Society of Paediatric Oncology-Europe (SIOP-E) during the last decades. Today, two out of three patients survive. At least 8000 long-term childhood brain tumour survivors (CBTS) are currently living in Germany. They face lifelong disease- and treatment-related late effects (LE) and associated socioeconomic problems more than many other childhood cancer survivors (CCS).

METHOD

We review the LE and resulting special needs of this particular group of CCS.

RESULTS

Despite their increasing relevance for future treatment optimisation, neither the diversity of chronic and cumulative LE nor their pertinent risk factors and subsequent impact on quality of survival have yet been comprehensively addressed for CBTS treated according to HIT- or SIOP-E-protocols. Evidence-based information to empower survivors and stakeholders, as well as medical expertise to manage their individual health care, psychosocial and educational/vocational needs must still be generated and established.

CONCLUSION

The establishment of a long-term research- and care network in Germany shall contribute to a European platform, that aims at optimising CBTSs' transition into adulthood as resilient individuals with high quality of survival including optimal levels of activity, participation and acceptance by society.

Intraoperative neurosonography revisited: effective neuronavigation in pediatric neurosurgery

Intraoperative ultrasonography (IOUS) is a widely used noninvasive method to evaluate the morphology, vasculature, and pathologies of the brain. The advantages of IOUS include realtime depiction of neuroanatomy, accurate localization and characterization of a lesion, reduced surgical exploration and surgical time, and presumably decreased patient morbidity. IOUS is useful in the intraoperative monitoring of lesion resection as well as intraoperative localization and characterization of focal parenchymal lesions. This review aims to provide an overview of the clinical application of IOUS in pediatric intracranial neurosurgery.

Guiding brain tumor resection using surface-enhanced Raman scattering nanoparticles and a hand-held Raman scanner

The current difficulty in visualizing the true extent of malignant brain tumors during surgical resection represents one of the major reasons for the poor prognosis of brain tumor patients. Here, we evaluated the ability of a hand-held Raman scanner, guided by surface-enhanced Raman scattering (SERS) nanoparticles, to identify the microscopic tumor extent in a genetically engineered RCAS/tv-a glioblastoma mouse model. In a simulated intraoperative scenario, we tested both a static Raman imaging device and a mobile, hand-held Raman scanner. We show that SERS image-guided resection is more accurate than resection using white light visualization alone. Both methods complemented each other, and correlation with histology showed that SERS nanoparticles accurately outlined the extent of the tumors. Importantly, the hand-held Raman probe not only allowed near real-time scanning, but also detected additional microscopic foci of cancer in the resection bed that were not seen on static SERS images and would otherwise have been missed. This technology has a strong potential for clinical translation because it uses inert gold-silica SERS nanoparticles and a hand-held Raman scanner that can guide brain tumor resection in the operating room.

3T intraoperative MRI for management of pediatric CNS neoplasms

BACKGROUND AND PURPOSE

High-field-strength intraoperative MR imaging has emerged as a powerful adjunct for resection of brain tumors. However, its exact role has not been firmly established. We sought to determine the impact of 3T-intraoperative MRI on the surgical management of childhood CNS tumors.

MATERIALS AND METHODS

We evaluated patient data from a single academic children's hospital during a consecutive 24-month period after installation of a 3T-intraoperative MRI. Tumor location, histology, surgical approach, operating room time, presence and volume of residual tumor, need for tumor and non-tumor-related reoperation, and anesthesia- and MR imaging-related complications were evaluated. Comparison with pre-intraoperative MRI controls was performed.

RESULTS

One hundred ninety-four patients underwent intraoperative MRI-guided surgery. Of these, 168 were 18 years or younger (mean, 8.9 ± 5.0 years; 108 males/60 females). There were 65 posterior fossa tumors. The most common tumors were pilocytic astrocytoma (n = 31, 19%), low-grade glioma (n = 31, 19%), and medulloblastoma (n = 20, 12%). An average of 1.2 scanning sessions was performed per patient (maximum, 3). There were no MR imaging-related safety issues. Additional tumor was resected after scanning in 21% of patients. Among patients with a preoperative goal of gross total resection, 93% achieved this goal. The 30-day reoperation rate was <1% (n = 1), and no patient required additional postoperative MR imaging during the same hospital stay.

CONCLUSIONS

Intraoperative MRI is safe and increases the likelihood of gross total resection, albeit with increased operating room time, and reduces the need for early reoperation or repeat sedation for postoperative scans in children with brain tumors.

High-frequency intra-operative ultrasound-guided surgery of superficial intra-cerebral lesions via a single-burr-hole approach

The study described here examined the feasibility of using high-frequency intra-operative ultrasound (hfioUS) guidance to resect superficial intra-cerebral lesions through a single burr hole. A cohort of 23 consecutive patients with a total of 24 intra-cerebral lesions (9 intra-cerebral metastases, 8 gliomas, 4 infections, 2 lymphomas and 1 cavernoma) were studied. All lesions could be localized and successfully resected, biopsied or aspirated, and histopathological diagnoses were obtained in all cases. The mean operating time was 59.6 ± 23.9 min. The mean cross-sectional lesion size was 6.4 ± 7.6 cm(2), and the mean cortex surface-to-lesion distance was 0.6 ± 0.8 cm. Our results illustrate the feasibility of identifying and resecting superficial intra-cerebral lesions under hfioUS guidance via a single-burr-hole approach. We were able to achieve short resection times with no post-operative complications in all patients, favorable conditions under which to start adjuvant therapy when indicated.