Comprehensive assessment of hemorrhage risks and outcomes after stereotactic brain biopsy

Neurovascular Interventions for Neurotrauma: From Treatment of Injured Vessels to Treatment of the Injured Brain?

Traumatic brain injury is often associated with a direct or secondary neurovascular pathology. In this review, we present recent advancements in endovascular neurosurgery that enable accurate and effective vessel reconstruction with emphasis on its role in early diagnosis, the expanding use of flow diversion in pseudoaneurysms, and traumatic arteriovenous fistulas. In addition, future directions in which catheter-based interventions could potentially affect traumatic brain injury are described: targeting blood brain barrier integrity using the advantages of intra-arterial drug delivery of blood brain barrier stabilizers to prevent secondary brain edema, exploring the impact of endovascular venous access as a means to modulate venous outflow in an attempt to reduce intracranial pressure and augment brain perfusion, applying selective intra-arterial hypothermia as a neuroprotection method mitigating some of the risks conferred by systemic cooling, trans-vessel wall delivery of regenerative therapy agents, and shifting attention using multimodal neuromonitoring to post-traumatic vasospasm to further characterize the role it plays in secondary brain injury. Thus, we believe that the potential of endovascular tools can be expanded because they enable access to the "highways" governing perfusion and flow and call for further research focused on exploring these routes because it may contribute to novel endovascular approaches currently used for treating injured vessels, harnessing them for treatment of the injured brain.

Clinical protocol: Feasibility of evaluating abemaciclib neuropharmacokinetics of diffuse midline glioma using intratumoral microdialysis

Diffuse midline gliomas (DMG) are the most aggressive brain tumors of childhood and young adults, with documented 2-year survival rates <10%. Treatment failure is due in part to the function of the BBB. Intratumoral microdialysis sampling is an effective tool to determine brain entry of varied agents and could help to provide a better understanding of the relationship of drug permeability to DMG treatment responsivity. This is a non-randomized, single-center, phase 1 clinical trial. Up to seven young adult (18-39 years) patients with recurrent high-grade or diffuse midline glioma will be enrolled with the goal of 5 patients completing the trial over an anticipated 24 months. All patients will take abemaciclib pre-operatively for 4.5 days at twice daily dosing. Patients will undergo resection or biopsy, placement of a microdialysis catheter, and 48 hours of dialysate sampling coupled with timed plasma collections. If intratumoral tumor or brain dialysate sampling concentrations are >10nmol/L, or tumor tissue studies demonstrate CDK inhibition, then restart of abemaciclib therapy along with temozolomide will be administered for maintenance therapy and discontinued with evidence of radiologic or clinical disease progression. The poor survival associated with diffuse midline gliomas underscore the need for improved means to evaluate efficacy of drug delivery to tumor and peritumoral tissue. The findings of this novel study, will provide real-time measurements of BBB function which have the potential to influence future prognostic and diagnostic decisions in such a lethal disease with limited treatment options. Trial registration: Clinicaltrials.gov, NCT05413304. Registered June 10, 2022, Abemaciclib Neuropharmacokinetics of Diffuse Midline Glioma Using Intratumoral Microdialysis.

High intratumoral susceptibility signal grade on susceptibility-weighted imaging: a risk factor for hemorrhage after stereotactic biopsy

OBJECTIVE

This study aimed to examine the association of preoperative intratumoral susceptibility signal (ITSS) grade with hemorrhage after stereotactic biopsy (STB).

METHODS

The authors retrospectively reviewed 66 patients who underwent STB in their institution. Preoperative factors including age, sex, platelet count, prothrombin time-international normalized ratio, activated thromboplastin time, antiplatelet agent use, history of diabetes mellitus and hypertension, target location, anesthesia type, and ITSS data were recorded. ITSS was defined as a dot-like or fine linear low signal within a tumor on susceptibility-weighted imaging (SWI) and was graded using a 3-point scale: grade 1, no ITSS within the lesion; grade 2, 1-10 ITSSs; and grade 3, ≥ 11 ITSSs. Postoperative final tumor pathology was also reviewed. The association between preoperative variables and the size of postoperative hemorrhage was examined.

RESULTS

Thirty-four patients were men and 32 were women. The mean age was 66.6 years. The most common tumor location was the frontal lobe (27.3%, n = 18). The diagnostic yield of STB was 93.9%. The most common pathology was lymphoma (36.4%, n = 24). The ITSS was grade 1 in 37 patients (56.1%), grade 2 in 14 patients (21.2%), and grade 3 in 15 patients (22.7%). Interobserver agreement for ITSS was almost perfect (weighted kappa = 0.87; 95% CI 0.77-0.98). Age was significantly associated with ITSS (p = 0.0075). Postoperative hemorrhage occurred in 17 patients (25.8%). Maximum hemorrhage diameter (mean ± SD) was 1.78 ± 1.35 mm in grade 1 lesions, 2.98 ± 2.2 mm in grade 2 lesions, and 9.51 ± 2.11 mm in grade 3 lesions (p = 0.01). Hemorrhage > 10 mm in diameter occurred in 10 patients (15.2%), being symptomatic in 3 of them. Four of 6 patients with grade 3 ITSS glioblastomas (66.7%) had postoperative hemorrhages > 10 mm in diameter. After adjusting for age, ITSS grade was the only factor significantly associated with hemorrhage > 10 mm (p = 0.029). Compared with patients with grade 1 ITSS, the odds of postoperative hemorrhage > 10 mm in diameter were 2.57 times higher in patients with grade 2 ITSS (95% CI 0.31-21.1) and 9.73 times higher in patients with grade 3 ITSS (95% CI 1.57-60.5).

CONCLUSIONS

ITSS grade on SWI is associated with size of postoperative hemorrhage after STB.

The risk factors of hemorrhage in stereotactic needle biopsy for brain lesions in a large cohort: 10 years of experience in a single center

BACKGROUND

This study aimed to identify the risk factors for hemorrhage from a large cohort who underwent stereotactic needle biopsy for brain lesions at a single center over a 10-year period.

METHODS

We performed a retrospective chart review of consecutive patients who underwent stereotactic biopsy at our institute between January 2010 and December 2019. Demographic characteristics and clinical variables were collected and analyzed to identify risk factors for postbiopsy hemorrhage using the chi-square test and univariable and multivariable logistic regression analyses.

RESULTS

A total of 3196 patients were included in this study; of these, a histological diagnosis was eventually made for 2938 (91.93%) patients. Hemorrhage occurred in 149 (4.66%) patients, and symptomatic hemorrhage occurred in 46 (1.44%) patients. In multivariable logistic regression analyses, the presence of deep-seated lesions (OR 1.272, p = 0.035), concomitant edema and enhancement on MR imaging scans (OR 1.827, p = 0.002), intraoperative hypertension without a past history (OR 1.012, p = 0.024), and the presence of high-grade glioma (OR 0.306, p = 0.003) were identified as independent predictors of hemorrhage after biopsy.

CONCLUSION

Stereotactic needle biopsy is a safe and effective way to obtain tissue from brain lesions for histological diagnosis. The presence of deep-seated lesions, concomitant edema, and enhancement on MR imaging scans and the presence of high-grade glioma are independent predictors of hemorrhage after stereotactic biopsy.

A Case Series of Stereotactic Biopsy of Brainstem Lesions through the Transfrontal Approach

Background and Importance Brainstem lesions may be unresectable or unapproachable. Regardless, the histopathological diagnosis is fundamental to determine the most appropriate treatment. We present our experience with transfrontal stereotactic biopsy technique for brainstem lesions as a safe and effective surgical route even when contralateral transhemispheric approach is required for preservation of eloquent tissue.

Clinical Presentation Twenty-five patients underwent surgery by transfrontal approach. Medical records were reviewed for establishing the number of patients who had postoperative histopathological diagnosis and postoperative complications. Twenty-four patients (18 adults and 7 children) had histopathological diagnosis. There were 18 astrocytomas documented, of which 12 were high grade and 6 low grade. The other diagnoses included viral encephalitis, post–renal transplant lymphoproliferative disorder, nonspecific chronic inflammation, Langerhans cell histiocytosis, and two metastases. No case was hindered by cerebrospinal fluid loss or ventricular entry. Complications included a case of mesencephalic hemorrhage with upper limb monoparesis and a case of a partially compromised third cranial nerve in another patient without associated bleeding.

Conclusion Stereotactic biopsy of brainstem lesions by transfrontal ipsilateral or transfrontal transhemispheric contralateral approaches is a safe and effective surgical approach in achieving a histopathological diagnosis in both pediatric and adult populations.

Platelet abnormalities in patients with Parkinson's disease undergoing preoperative evaluation for deep brain stimulation

Normal hemostatic function is important for reduction of the risk of intracranial hemorrhage during stereotactic neurosurgery including deep brain stimulation (DBS) surgery. This study investigates the hemostatic function in patients with Parkinson’s disease (PD) undergoing preoperative evaluation for DBS, with emphasis on the number and function of platelets. In 107 PD patients, only one had abnormal activated partial prothrombin time and normal prothrombin time. Among the other 106 patients, six (5.7%) had only thrombocytopenia, seven (6.6%) only prolonged bleeding time (BT), and 14 (13.2%) only prolonged closure time (CT) of platelet function analyzer 100 (PFA-100). Totally, 34 of the 106 patients (32.1%) had at least one of three kinds of platelet abnormalities. No factor was found to be associated with the occurrence of platelet abnormalities except that abnormal platelet group and prolonged BT subgroup had more patients using selegiline and lower UPDRS-III motor subscore with medication off than normal platelet group (p < 0.05). The use of selegiline was significantly correlated with prolonged BT (p = 0.0041) and platelet abnormality (p = 0.0197). Therefore, it is important to have detailed evaluation of the hemostatic function for PD patients undergoing preoperative evaluation for DBS, especially the platelet number and function.

Measurement of aspiration pressure in cannula brain tumour biopsy and its correlation with ultrasonographic elastography

BACKGROUND

Stereotactic brain biopsy is to perform the manual aspiration tissue biopsy using a cannula on a syringe under stereotactic guidance to provide histological confirmation. Excessive vacuum aspiration increases the risk of haemorrhage. Manual aspiration relies on the surgeon's experience while the minimum vacuum pressure is unknown.

OBJECTIVES

1. To assess the aspiration vacuum pressure range in cannula brain tumour biopsy; 2. To understand the correlation of ultrasound elastography data with the aspiration pressure.

METHODS

This prospective study has recruited 10 patients for stereotactic brain tumour biopsy. With the use of ultrasound elastography, strain ratio of the lesion was assessed in real time before biopsy. Vacuum aspiration pressures were recorded using a T-connector pressure sensor during the stereotactic biopsy.

RESULTS

A total of 11 biopsies were taken from 10 patients, including a bilateral biopsy for a patient with bifrontal lesions. The diagnostic yield was 100% in all the 10 patients with no symptomatic haemorrhage (but 2 subclinical haemorrhages in CT scan) nor infection. The vacuum pressures ranged from 40.34 to 65.61 kPa and the strain-ratio ranged from 0.405 to 2.74. Strain ratio of the lesion at the lower range required a lower range of aspiration pressure, whereas lesions of Strain ratio over 0.45 required a higher range of aspiration pressure.

CONCLUSION

A vacuum pressure of 40 to 66 kPas is safe and adequate for biopsy of various types of tumours with heterogenous elastographic characters. Ultrasonographic elastography may be a real-time guide for the minimum vacuum pressure required for biopsy.

An optimal brain tumor segmentation algorithm for clinical MRI dataset with low resolution and non-contiguous slices

Background

Segmenting brain tumor and its constituent regions from magnetic resonance images (MRI) is important for planning diagnosis and treatment. In clinical routine often an experienced radiologist delineates the tumor regions using multimodal MRI. But this manual segmentation is prone to poor reproducibility and is time consuming. Also, routine clinical scans are usually of low resolution. To overcome these limitations an automated and precise segmentation algorithm based on computer vision is needed.

Methods

We investigated the performance of three widely used segmentation methods namely region growing, fuzzy C means and deep neural networks (deepmedic). We evaluated these algorithms on the BRATS 2018 dataset by choosing randomly 48 patients data (high grade, n = 24 and low grade, n = 24) and on our routine clinical MRI brain tumor dataset (high grade, n = 15 and low grade, n = 28). We measured their performance using dice similarity coefficient, Hausdorff distance and volume measures.

Results

Region growing method performed very poorly when compared to fuzzy C means (fcm) and deepmedic network. Dice similarity coefficient scores for FCM and deepmedic algorithms were close to each other for BRATS and clinical dataset. The accuracy was below 70% for both these methods in general.

Conclusion

Even though the deepmedic network showed very high accuracy in BRATS challenge for brain tumor segmentation, it has to be custom trained for the low resolution routine clinical scans. It also requires large training data to be used as a stand-alone algorithm for clinical applications. Nevertheless deepmedic may be a better algorithm for brain tumor segmentation when compared to region growing or FCM.

Synchronous glioblastoma and brain metastases: illustrative case

BACKGROUND

Radiosurgical treatment of brain metastases is usually performed without brain tissue confirmation. While it is extremely rare for glioblastoma to develop concurrently in patients with brain metastases, they can look radiographically similar, and recognition is important because it alters management and prognosis. The synchronous presence of brain metastases and glioblastoma has not been published to date in the literature, making this a rare illustrative case.

OBSERVATIONS

A 70-year-old female had lung biopsy-proven metastatic lung adenocarcinoma and multiple brain metastases. Her treatment course included initial carboplatin, pemetrexed, and bevacizumab followed by maintenance nivolumab, and she underwent stereotactic radiosurgery to the multiple brain metastases. During interval radiological surveillance, one lesion in the right temporal lobe was noted to slowly progress associated with development of significant perilesional edema causing midline shift despite repeated stereotactic radiosurgical treatments. Biopsy of this lesion revealed glioblastoma, IDH wildtype.

LESSONS

Glioblastomas and brain metastases have similar radiological features, so the possibility of incorrect diagnosis needs to be considered for all lesions with interval growth poststereotactic radiosurgery. Biopsy and/or resection/laser ablation should be considered prior to reirradiation.

OCT-Guided Surgery for Gliomas: Current Concept and Future Perspectives

Optical coherence tomography (OCT) has been recently suggested as a promising method to obtain in vivo and real-time high-resolution images of tissue structure in brain tumor surgery. This review focuses on the basics of OCT imaging, types of OCT images and currently suggested OCT scanner devices and the results of their application in neurosurgery. OCT can assist in achieving intraoperative precision identification of tumor infiltration within surrounding brain parenchyma by using qualitative or quantitative OCT image analysis of scanned tissue. OCT is able to identify tumorous tissue and blood vessels detection during stereotactic biopsy procedures. The combination of OCT with traditional imaging such as MRI, ultrasound and 5-ALA fluorescence has the potential to increase the safety and accuracy of the resection. OCT can improve the extent of resection by offering the direct visualization of tumor with cellular resolution when using microscopic OCT contact probes. The theranostic implementation of OCT as a part of intelligent optical diagnosis and automated lesion localization and ablation could achieve high precision, automation and intelligence in brain tumor surgery. We present this review for the increase of knowledge and formation of critical opinion in the field of OCT implementation in brain tumor surgery.

Less common intraparenchymal tumors

The chapter outlines the management of a great variety of rare intraparenchymal tumors. For some like medulloblastomas or ependymomas, GKNS has little to offer. For others like neurocytomas, primary central nervous system lymphomas, and papillary pineal tumors the current findings look most hopeful. For choroid plexus papillomas there is currently not enough information to define the role of GKNS in their treatment. Pineal region tumors are a complex and varied group of neoplasms. Their complexity, variety and ethnic variability means that defining the role of GKNS will require continuing research before a consensus about management can be reached.

Versatile Use of Intraoperative Ultrasound Guidance for Brain Puncture

BACKGROUND

Intraoperative ultrasound (iUS) is an effective guidance and imaging system commonly used in neuro-oncological surgery. Despite the versatility of iUS, its utility for single burr hole puncture guidance remains fairly underappreciated.

OBJECTIVE

To highlight the simplicity, versatility, and effectiveness of iUS guidance in brain puncture by presenting the current case series and technical note collection.

METHODS

We present 4 novel uses of iUS guidance for single burr hole brain puncture: cannulation of normal-sized ventricles, endoscopic third ventriculostomy (ETV) guidance, evacuation of interhemispheric empyema, and stereotactic biopsy assistance.

RESULTS

All techniques were performed successfully in a total of 16 patients. Normal-sized ventricles were cannulated in 7 patients, among whom 5 underwent Ommaya reservoir placement and 2 underwent ventriculoperitoneal shunt placement for idiopathic intracranial hypertension. No more than 1 attempt was needed for cannulation. All ventricular tip positions were optimal as shown by postoperative imaging. iUS guidance was used in 5 ETV procedures. The working cannula was successfully introduced to the lateral ventricle, providing the optimal trajectory to the third ventricular floor in these cases. Interhemispheric subdural empyema was aspirated with iUS guidance in 1 patient. Volume reduction was clearly visible, allowing near-total evacuation of the empyema. iUS guidance was used for assistive purposes during stereotactic biopsy in 3 patients. No major perioperative complications were observed throughout this series.

CONCLUSION

iUS is an effective and versatile guidance system that allows for real-time imaging and can be easily and safely employed for various brain puncture procedures.

Related factors with diagnostic yield and intracranial hemorrhagic complications in frame-based stereotactic biopsy. Review

The frame-based stereotactic biopsy is a minimally invasive technique that allows us to obtain a sample of brain tissue for subsequent diagnosis and treatment. The scope of this article is to review the published data related to the factors that could condition its diagnostic yield, and the appearance of post-biopsy hemorrhagic complications. PubMed search, last updated June 2020, was conducted using the terms "stereotactic biopsy", "diagnostic yield" and "intracranial post-biopsy hemorrhage". A total of 38 studies, that showed descriptive or analytical results, were included, and reviewed. Our literature review show that some characteristics of the lesion and surgical procedure peculiarities are significantly related with the effectiveness and safety of the technique. In this way, they must be taken into account in order to optimize its results.

Factors affecting diagnostic yield in stereotactic biopsy for brain lesions: a 5-year single-center series

The objective of this study is to determine the factors that are associated with the diagnostic yield of stereotactic brain biopsy. A retrospective analysis was performed on 50 consecutive patients who underwent stereotactic brain biopsies in a single institute from 2014 to 2019. Variables including age, gender, lesion topography and characteristics, biopsy methods, and surgeon's experience were analyzed along with diagnostic rate. This study included 31 male and 19 female patients with a mean age of 48.4 (range: 1-76). Of these, 25 underwent frameless brain-suite stereotactic biopsies, 15 were frameless Portable Brain-lab® stereotactic biopsies and 10 were frame-based CRW® stereotactic biopsies. There was no statistical difference between the diagnostic yield of the three methods. The diagnostic yield in our series was 76%. Age, gender, and biopsy methods had no impact on diagnostic yield. Periventricular and pineal lesion biopsies were significantly associated with negative diagnostic yield (p = 0.01) whereas larger lesions were significantly associated with a positive yield (p = 0.01) with the mean volume of lesions in the positive yield group (13.6 cc) being higher than the negative yield group (7 cc). The diagnostic yields seen between senior and junior neurosurgeons in the biopsy procedure were 95% and 63%, respectively (p = 0.02). Anatomical location of the lesion, volume of the lesion, and experience of the surgeon have significant impacts on the diagnostic yield in stereotactic brain biopsy. There was no statistical difference between the diagnostic yield of the three methods, age, gender, and depth of lesion.

Severity, timeline, and management of complications after stereotactic brain biopsy

OBJECTIVE

The literature shows discrepancies in stereotactic brain biopsy complication rates, severities, and outcomes. Little is known about the timeline of postbiopsy complications. This study aimed to analyze 1) complications following brain biopsies, using a graded severity scale, and 2) a timeline of complication occurrence. The secondary objectives were to determine factors associated with an increased risk of complications and to assess complication-related management and extra costs.

METHODS

The authors retrospectively examined 1500 consecutive stereotactic brain biopsies performed in adult patients at their tertiary medical center between April 2009 and April 2019.

RESULTS

Three hundred eighty-one biopsies (25.4%) were followed by a complication, including 88.2% of asymptomatic hemorrhages. Symptomatic complications involved 3.0% of the biopsies, and 0.8% of the biopsies were fatal. The severity grading scale had a 97.6% interobserver reproducibility. Twenty-three (51.1%) of the 45 symptomatic complications occurred within the 1st hour following the biopsy, while 75.6% occurred within the first 6 hours. Age ≥ 65 years, second biopsy procedures, gadolinium-enhanced lesions, glioblastomas, and lymphomas were predictors of biopsy-related complications. Brainstem biopsy-targeted lesions and cerebral toxoplasmosis were predictive of mortality. Asymptomatic hemorrhage was associated with delayed (> 6 hours) symptomatic complications. Symptomatic complications led to extended hospitalization in 86.7% of patients. The average extra cost for management of a patient with postbiopsy symptomatic complication was $35,702.

CONCLUSIONS

Symptomatic complications from brain biopsies are infrequent but associated with substantial adverse effects and cost implications for the healthcare system. The use of a severity grading scale, as the authors propose in this article, helps to classify complications according to the therapeutic consequences and the patient's outcome. Because this study indicates that most complications occur within the first few hours following the biopsy, postbiopsy monitoring can be tailored accordingly. The authors therefore recommend systematic monitoring for 2 hours in the recovery unit and a CT scan 2 hours after the end of the biopsy procedure. In addition, they propose a modern algorithm for optimal postoperative management of patients undergoing stereotactic biopsy.

Outpatient stereotactic brain biopsies

Outpatient neurosurgery is rising popularity leading to patients’ satisfaction and cost-savings. Although several North-American teams have shown the safety of outpatient stereotactic brain biopsies, few data from other countries with different health care systems are available. We therefore conducted a feasibility and safety study on the outpatient stereotactic brain biopsies. We prospectively examined all the consecutive stereotactic brain biopsies performed in an outpatient setting at our tertiary medical center, between June 2018 and September 2020. Among the 437 patients who underwent stereotactic brain biopsy during the study period, 40 (9.2%) patients were enrolled for an outpatient management. The sex ratio was 1 and the median age on biopsy day was 55 [41–66] years. The median distance from patients’ home to hospital was 17 km [3–47]. 95% of patients had pre-biopsy ASA score of 1 or 2 and mRs equal to 2 or less. The rate of same-day discharge was 100%. No patient experienced post-biopsy symptomatic complication necessitating readmission within the month following the biopsy. One patient (2.5%) resorted to an unplanned consultation. Histological findings obtained from brain biopsy led to a diagnosis in all patients; the most frequently found were neoplastic lesions (77.5%). Stereotactic brain biopsies can therefore be safely achieved on an outpatient setting in carefully selected patients. This process could be more widely adopted in other neurosurgical centers, without affecting the quality of patient’s health care and safety. In this article, we propose management guidelines and pre-biopsy checklist for performing ambulatory stereotactic brain biopsies.

Application of multimodal MRI and radiologic features for stereotactic brain biopsy: insights from a series of 208 patients

OBJECTIVES

We reviewed our institutional experience during a 10-year period for improvement of safety and efficacy of stereotactic biopsy procedures.

METHODS

We performed a retrospective review of inpatient summaries, stereotactic worksheets and radiologic investigations of 208 consecutive patients, who underwent MRI-guided stereotactic biopsies between March 2010 and March 2020.

RESULTS

The overall diagnostic yield was 96.2%. CT-confirmed intracranial hemorrhage occurred in 17 patients (8.2%), and the overall mortality rate was 0.5%. Combined MRS and PWI helped target selection in 27 cases (13.0%), the diagnostic yield was 100%. The results of the regression analysis revealed that non-diagnostic biopsy specimen significantly correlated with the cystic trait (p<.01) and edema of lesions (p<.05). Enhancement (p<.01) is shown to be an important factor for obtaining a diagnostic biopsy. Furthermore, the edema trait of lesions (p<.01) showed the important factors of hemorrhage.

CONCLUSIONS

The radiological features of lesions and use of the most suitable MRI sequences during biopsy planning are recommended ways to improve the diagnostic yield and safety of this technique.

Noninvasively Evaluating the Grading of Glioma by Multiparametric Magnetic Resonance Imaging

RATIONALE AND OBJECTIVE

To investigate the performance of multi-parametric magnetic resonance imaging (MRI) for glioma grading.

MATERIALS AND METHODS

Seventy consecutive patients with histopathologically confirmed glioma were retrospectively evaluated by conventional MRI, dynamic susceptibility-weighted contrast-enhanced, multiple diffusion-weighted imaging signal models including mono-exponential, bi-exponential, stretched exponential, and diffusion kurtosis imaging. One-way analysis of variance and independent-samples t test were used to compare the MR parameter values between low and high grades as well as among all grades of glioma. Receiver operating characteristic analysis, Spearman's correlation analysis, and binary logistic regression analysis were used to assess their diagnostic performance.

RESULTS

The diagnostic performance (the optimal thresholds, area under the receiver operating characteristic curve, sensitivity, and specificity) was achieved with normalized relative cerebral blood flow (rCBV) (2.240 ml/100 g, 0.844, 87.8%, and 75.9%, respectively), mean kurtosis (MK) (0.471, 0.873, 92.7%, and 79.3%), and water molecular diffusion heterogeneity index (α) (1.064, 0.847, 79.3% and 78.0%) for glioma grading. There were positive correlations between rCBV and MK and the tumor grades and negative correlations between α and the tumor grades (p < 0.01). The parameter of α yielded a diagnostic accuracy of 85.3%, the combination of MK and α yielded a diagnostic accuracy of 89.7%, while the combination of rCBV, MK, and α were more accurate (94.2%) in predicting tumor grade.

CONCLUSION

The most accurate parameters were rCBV, MK, and α in dynamic susceptibility-weighted contrast, diffusion kurtosis imaging, and Multi-b diffusion-weighted imaging for glioma grading, respectively. Multiparametric MRI can increase the accuracy of glioma grading.

Pineal Gland Tumors: A Review

Simple Summary

Pineal neoplasms are tumors with different and variable morphological, histological, and radiological characteristics and, consequently different diagnosis and management. Due to their rarity, pineal tumors may be misdiagnosed. Pineal tumors, are divided into germ cell tumors, pineal parenchymal tumors and tumors that derive from adjacent structures. In this review, we report the clinical relevance of the main pineal gland tumors, underlining the importance of studying the triggering causes of pineal region carcinogenesis, to realize appropriate diagnosis and, consequently, better clinical management.

Abstract

The pineal gland is a small, pinecone-shaped endocrine gland that participates in the biological rhythm regulation of vertebrates. The recognized major product of the pineal gland is melatonin—a multifunctional endogenous indoleamine. Accumulating evidence suggests that the pineal gland is important for preserving ideal health conditions in vertebrate. Tumors of the pineal region account for approximately 3–11% of pediatric brain neoplasms but fewer than 1% of brain neoplasms in adults. It is fundamental to expand advanced imaging techniques together with both clinical and laboratory knowledge, to help to differentiate among pineal neoplasms and thus facilitate accurate primary diagnoses and proper therapeutic interventions. In this review, we report the gross anatomy of the pineal gland and its functional significance and discuss the clinical relevance of pineal gland tumors, underlining the importance of identifying the leading causes of pineal region masses.

Safety assessment of intraparenchymal central nervous system biopsies: Single institution healthcare value review

The study objective was to evaluate a single institution experience with adult stereotactic intracranial biopsies and review any projected cost savings as a result of bypassing intensive care unit (ICU) admission and limited routine head computed tomography (CT). The authors retrospectively reviewed all stereotactic intracranial biopsies performed at a single institution between February 2012 and March 2019. Primary data collection included ICU length of stay (LOS), hospital LOS, ICU interventions, need for reoperation, and CT use. Secondarily, location of lesion, postoperative hematoma, neurological deficit, pathology, and preoperative coagulopathy data were collected. There were 97 biopsy cases (63% male). Average age, ICU LOS, and total hospital stay were 58.9 years (range; 21-92 years), 2.3 days (range; 0-40 days), and 8.8 days (range 1-115 days), respectively. Seventy-five (75 of 97) patients received a postoperative head CT. No patients required medical or surgical intervention for complications related to biopsy. Eight patients required transfer from the ward to the ICU (none directly related to biopsy). Nine patients transferred directly to the ward postoperatively (none required transfer to ICU). Of the patients who did not receive CT or went directly to the ward, none had extended LOS or required transfer to ICU for neurosurgical concerns. Eliminating routine head CT and ICU admission translates to approximately $584,971 in direct cost savings in 89 cases without a postoperative ICU requirement. These practice changes would save patients' significant hospitalization costs, decrease healthcare expenditures, and allow for more appropriate hospital resource use.

Differentiation Between Ependymoma and Medulloblastoma in Children with Radiomics Approach

RATIONALE AND OBJECTIVES

Ependymoma (EP) and medulloblastoma (MB) of children are similar in age, location, manifestations and symptoms. Therefore, it is difficult to differentiate them through visual observation in clinical diagnosis. The aim of this study is to investigate the effectiveness of radiomics and machine-learning techniques on multimodal magnetic resonance imaging (MRI) in distinguish EP from MB.

MATERIALS AND METHODS

Three dimensional (3D) tumors were semi-automatic segmented by radiologists from postcontrast T1-weighted images and apparent diffusion coefficient maps in 51 patients (24 EPs, 27 MBs). Then, we extracted radiomics features and further reduced them by three feature selection methods. For each feature selection method, 4 classifiers were adopted which yield 12 different models. After extensive crossvalidation, pairwise test were carried out in receiver operating characteristic curves to explore performance of these models.

RESULTS

The radiomics model built with multivariable logistic regression as feature selection method and random forests as classifier had the best performance, area under the curve achieved 0.91 (95 % confidence interval 0.787-0.968). Five relevant features were highly correlated to discriminate EP and MB, which may used as imaging biomarkers to predict the kinds of tumors.

CONCLUSION

The combination of radiomics and machine-learning approach on 3D multimodal MRI could well distinguish EP and MB of childhood, which assistant doctors in clinical diagnosis. Since there is no uniform model to obtained best performance for every specific data set, it is necessary to try different combination methods.

Multi-modal magnetic resonance imaging-based grading analysis for gliomas by integrating radiomics and deep features

Background

To investigate the feasibility of integrating global radiomics and local deep features based on multi-modal magnetic resonance imaging (MRI) for developing a noninvasive glioma grading model.

Methods

In this study, 567 patients [211 patients with glioblastomas (GBMs) and 356 patients with low-grade gliomas (LGGs)] between May 2006 and September 2018, were enrolled and divided into training (n=186), validation (n=47), and testing cohorts (n=334), respectively. All patients underwent postcontrast enhanced T1-weighted and T2 fluid-attenuated inversion recovery MRI scanning. Radiomics and deep features (trained by 8,510 3D patches) were extracted to quantify the global and local information of gliomas, respectively. A kernel fusion-based support vector machine (SVM) classifier was used to integrate these multi-modal features for grading gliomas. The performance of the grading model was assessed using the area under receiver operating curve (AUC), sensitivity, specificity, Delong test, and t-test.

Results

The AUC, sensitivity, and specificity of the model based on combination of radiomics and deep features were 0.94 [95% confidence interval (CI): 0.85, 0.99], 86% (95% CI: 64%, 97%), and 92% (95% CI: 75%, 99%), respectively, for the validation cohort; and 0.88 (95% CI: 0.84, 0.91), 88% (95% CI: 80%, 93%), and 81% (95% CI: 76%, 86%), respectively, for the independent testing cohort from a local hospital. The developed model outperformed the models based only on either radiomics or deep features (Delong test, both of P<0.001), and was also comparable to the clinical radiologists.

Conclusions

This study demonstrated the feasibility of integrating multi-modal MRI radiomics and deep features to develop a promising noninvasive grading model for gliomas.

Between-hospital variation in rates of complications and decline of patient performance after glioblastoma surgery in the dutch Quality Registry Neuro Surgery

Introduction

For decisions on glioblastoma surgery, the risk of complications and decline in performance is decisive. In this study, we determine the rate of complications and performance decline after resections and biopsies in a national quality registry, their risk factors and the risk-standardized variation between institutions.

Methods

Data from all 3288 adults with first-time glioblastoma surgery at 13 hospitals were obtained from a prospective population-based Quality Registry Neuro Surgery in the Netherlands between 2013 and 2017. Patients were stratified by biopsies and resections. Complications were categorized as Clavien-Dindo grades II and higher. Performance decline was considered a deterioration of more than 10 Karnofsky points at 6 weeks. Risk factors were evaluated in multivariable logistic regression analysis. Patient-specific expected and observed complications and performance declines were summarized for institutions and analyzed in funnel plots.

Results

For 2271 resections, the overall complication rate was 20 % and 16 % declined in performance. For 1017 biopsies, the overall complication rate was 11 % and 30 % declined in performance. Patient-related characteristics were significant risk factors for complications and performance decline, i.e. higher age, lower baseline Karnofsky, higher ASA classification, and the surgical procedure. Hospital characteristics, i.e. case volume, university affiliation and biopsy percentage, were not. In three institutes the observed complication rate was significantly less than expected. In one institute significantly more performance declines were observed than expected, and in one institute significantly less.

Conclusions

Patient characteristics, but not case volume, were risk factors for complications and performance decline after glioblastoma surgery. After risk-standardization, hospitals varied in complications and performance declines.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11060-021-03697-8.

Related factors with diagnostic yield and intracranial hemorrhagic complications in frame-based stereotactic biopsy. Review

The frame-based stereotactic biopsy is a minimally invasive technique that allows us to obtain a sample of brain tissue for subsequent diagnosis and treatment. The scope of this article is to review the published data related to the factors that could condition its diagnostic yield, and the appearance of post-biopsy hemorrhagic complications. PubMed search, last updated June 2020, was conducted using the terms "stereotactic biopsy", "diagnostic yield" and "intracranial post-biopsy hemorrhage". A total of 38 studies, that showed descriptive or analytical results, were included, and reviewed. Our literature review show that some characteristics of the lesion and surgical procedure peculiarities are significantly related with the effectiveness and safety of the technique. In this way, they must be taken into account in order to optimize its results.

How to avoid pneumocephalus in deep brain stimulation surgery? Analysis of potential risk factors in a series of 100 consecutive patients

BACKGROUND

Accuracy of lead placement is the key to success in deep brain stimulation (DBS). Precise anatomic stereotactic planning usually is based on stable perioperative anatomy. Pneumocephalus due to intraoperative CSF loss is a common procedure-related phenomenon which could lead to brain shift and targeting inaccuracy. The aim of this study was to evaluate potential risk factors of pneumocephalus in DBS surgery.

METHODS

We performed a retrospective single-center analysis in patients undergoing bilateral DBS. We quantified the amount of pneumocephalus by postoperative CT scans and corrected the data for accompanying brain atrophy by an MRI-based score. Automated computerized segmentation algorithms from a dedicated software were used. As potential risk factors, we evaluated the impact of trephination size, the number of electrode tracks, length of surgery, intraoperative blood pressure, and brain atrophy.

RESULTS

We included 100 consecutive patients that underwent awake DBS with intraoperative neurophysiological testing. Systolic and mean arterial blood pressure showed a substantial impact with an inverse correlation, indicating that lower blood pressure is associated with higher volume of pneumocephalus. Furthermore, the length of surgery was clearly correlated to pneumocephalus.

CONCLUSION

Our analysis identifies intraoperative systolic and mean arterial blood pressure as important risk factors for pneumocephalus in awake stereotactic surgery.

Neurological diseases of unknown etiology: Brain-biopsy diagnostic yields and safety

BACKGROUND

For nonneoplastic neurological diseases, no recommendation exists regarding the place or appropriate timing of brain biopsy. The aim of this study was to evaluate the diagnostic yield and safety of brain biopsies from patients with neurological diseases of unknown etiology.

METHODS

We performed a retrospective cohort study from January 1, 2008 to December 31, 2018. We analyzed 1847 brain-biopsied patients, including 178 biopsies indicated for neurological diseases of unknown etiology. Specific histological and final diagnosis rates, positive diagnosis-associated factors, complication rate and complication-associated factors were assessed.

RESULTS

Specific histological diagnosis and final diagnosis rates were 71.3% and 83.1%, respectively, leading to therapeutic management change(s) for 75.3% of patients. Brain- biopsy-related mortality and permanent neurological morbidity occurred in 1.1% and 0.6% of the patients, respectively. The multivariable logistic-regression model retained (odds ratio [95% CI] only immunodepression (2.2 [1.1-4.7]; P=.04) as being independently associated with specific histological diagnosis, while supratentorial biopsy-targeted lesions (4.1 [1.1-15.2]; P=.04) were independently associated with a final diagnosis. Biopsies obtained from comatose patients were less contributive to the diagnosis (0.2 [0.05-0.7]; P=.01). Prebiopsy platelet count <100 G/L (28.5 [1.8-447]; P=.02), hydrocephalus (6.3 [1.2-15.3]; P=.02) and targeted lesions <1 cm (4.3 [1.2-15.3]; P=.03) were independently associated with brain biopsy-related complications.

CONCLUSION

For highly selected patients with neurological diseases of unknown etiology, brain biopsy has a high diagnostic yield and low frequency of severe complications. We advocate that this procedure be considered early in the diagnosis algorithm of these patients.

Risk factors for adverse events occurring after recovery from stereotactic brain biopsy in dogs with primary intracranial neoplasia

BACKGROUND

Stereotactic brain biopsy (SBB) allows for histopathologic diagnosis of brain tumors. Adverse events (AE) occur in 5 to 29% of dogs after SBB, but risk factors associated with developing AE are poorly described.

OBJECTIVE

Identify clinicopathologic, diagnostic imaging, or procedural variables that are associated with AE in dogs after SBB.

ANIMALS

Twenty-nine dogs with brain tumors.

METHODS

Retrospective, case-control study. Dogs had laboratory investigations performed before SBB, as well as clinical examinations and diagnostic imaging of the brain before and after SBB. Cases experienced AE after SBB including transient exacerbation of preexisting neurologic deficits, transient new deficits, or permanent neurologic deficits. Controls had SBB performed without AE. Fisher's exact and Student's t tests were used to examine associations between the postulated risk factors and AE.

RESULTS

Adverse events occurred in 8/29 (27%) dogs, and 7/8 AE (88%) were transient. Cases were significantly more likely to have T2W-heterogenous tumors (88 versus 38%; P = .04) and lower platelet counts (194.75 ± 108.32 versus 284.29 ± 68.54 ×103 /mm3 , P = .006). Dogs with gradient echo signal voids present on baseline imaging were significantly more likely to have hemorrhage present after biopsy, and 7/8 (88%) of cases had hemorrhage on imaging after SBB.

CONCLUSION AND CLINICAL IMPORTANCE

Twenty-seven percent of dogs undergoing SBB experience AE, with the majority of AE resolving with 1 week. Platelet counts should be ≥185 000/mm3 to minimize risk of SBB-associated AE. Observation of intracranial hemorrhage after biopsy can have important clinical implications, as this was observed in 88% of dogs with AE.

Endoscopic versus stereotactic biopsies of intracranial lesions involving the ventricles

Stereotactic biopsies of ventricular lesions may be less safe and less accurate than biopsies of superficial lesions. Accordingly, endoscopic biopsies have been increasingly used for these lesions. Except for pineal tumors, the literature lacks clear, reliable comparisons of these two methods. All 1581 adults undergoing brain tumor biopsy from 2007 to 2018 were retrospectively assessed. We selected 119 patients with intraventricular or paraventricular lesions considered suitable for both stereotactic and endoscopic biopsies. A total of 85 stereotactic and 38 endoscopic biopsies were performed. Extra procedures, including endoscopic third ventriculostomy and tumor cyst aspiration, were performed simultaneously in 5 stereotactic and 35 endoscopic cases. In 9 cases (5 stereotactic, 4 endoscopic), the biopsies were nondiagnostic (samples were nondiagnostic or the results differed from those obtained from the resected lesions). Three people died: 2 (1 stereotactic, 1 endoscopic) from delayed intraventricular bleeding and 1 (stereotactic) from brain edema. No permanent morbidity occurred. In 6 cases (all stereotactic), additional surgery was required for hydrocephalus within the first month postbiopsy. Rates of nondiagnostic biopsies, serious complications, and additional operations were not significantly different between groups. Mortality was higher after biopsy of lesions involving the ventricles, compared with intracranial lesions in any location (2.4% vs 0.3%, p = 0.016). Rates of nondiagnostic biopsies and complications were similar after endoscopic or stereotactic biopsies. Ventricular area biopsies were associated with higher mortality than biopsies in any brain area.

Symptomatic intracranial hemorrhages and frame-based stereotactic brain biopsy

Background:

Stereotactic biopsy is a well-established procedure in neurosurgery. Our objective is to define the clinical, radiological, and technical factors that can condition the emergence of postbiopsy symptomatic intracranial hemorrhage. Based on our findings, we suggest recommendations to improve its usual clinical practice.

Methods:

We made a retrospective study of 429 cases with stereotactic biopsies performed in the past 37 years. The surgical procedure-was adapted in terms of the stereotactic frames (Todd-Wells, CRW, Leksell), neuroimaging tests, and planning programs available in the hospital. Fifty-three variables were analyzed for each patient (SPSS.23).

Results:

The diagnostic yield was 90.7%. Forty-one patients (9.5%) suffered a symptomatic postbiopsy hemorrhage; only 17 (3.9%) had permanent morbidity. The mortality was 0.93% (n = 4). A postsurgical CT scan was requested only in 99 patients (23%) of our series. Lesion mass effect, cystic component, contrast enhancement, histological nature, or number of targets were not associated with a greater risk of symptomatic postbiopsy hemorrhage (P > 0.05). On the other hand, the biopsies made by nonexpert neurosurgeons (P = 0.01) or under general anesthesia (P = 0.02) resulted in a greater risk of symptomatic postbiopsy hemorrhage. Anesthetic type was the clearest predictive factor of bleeding with this technique (OR: 0.24).

Conclusion:

Stereotactic biopsy is a very valuable tool. To optimize its safety and minimize the risk of intracranial bleeding, it requires both a knowledge of stereotactic techniques and very careful surgical planning. While the patient’s stay in intensive vigilance units after the procedure is a useful strategy, the request for control CT scans should be conditioned by the clinical evolution of each patient.

Cell-free Chromatin Immunoprecipitation (cfChIP) from blood plasma can determine gene-expression in tumors from non-small-cell lung cancer patients

OBJECTIVES

Lung cancer is the leading cause of cancer related death worldwide. Accurate molecular diagnostics from a tumor biopsy is paramount for correct diagnosis, treatment strategy, and prediction of outcome. However, a tumor biopsy can be misleading due to tumor heterogeneity and consecutive biopsies are rarely achievable. Importantly, tumor-specific genetic information concerning mutations and translocations, can also be obtained from liquid biopsies, e.g. blood plasma, containing cell-free DNA (cfDNA) with both systemic and tumor origin. Tumor-specific gene-expression information can also be determined from liquid biopsies using cfDNA methylation and cell-free RNA analyses. However, supplementary methodologies that can determine gene-expression patterns in lung tumors from liquid biopsies could also have diagnostic impact.

MATERIALS AND METHODS

We here present the method cell-free chromatin Immunoprecipitation (cfChIP), which for genes having high expression specifically in the tumor, can determine such gene-expression from blood plasma. In cfChIP cell-free nucleosomes modified with histone H3 lysine 36 tri-methylation (H3K36me3), a mark quantitatively correlated with the transcription of the underlying gene, are isolated, and associated cfDNA quantified.

RESULTS

We demonstrate that cfChIP from lung cancer patient blood plasma can successfully quantify the level of H3K36me3 associated with circulating cell-free nucleosomes and thereby quantify the transcriptional level of genes associated with these nucleosomes. Moreover, as a proof-of-principle we show that in blood plasma from 14 lung cancer patients, H3K36me3 cfChIP can replicate the expected higher expression of KRT6 in lung squamous cell carcinoma relative to adenocarcinoma.

CONCLUSION

This work shows that for genes with a high expression specifically in tumor, cfChIP can determine this gene-expression pattern from blood plasma. cfChIP is a method that determine gene-expression at the transcriptional level and accordingly can supplement cfDNA methylation and cell-free RNA analyses.

Radiomics MRI Phenotyping with Machine Learning to Predict the Grade of Lower-Grade Gliomas: A Study Focused on Nonenhancing Tumors

Objective

To assess whether radiomics features derived from multiparametric MRI can predict the tumor grade of lower-grade gliomas (LGGs; World Health Organization grade II and grade III) and the nonenhancing LGG subgroup.

Materials and Methods

Two-hundred four patients with LGGs from our institutional cohort were allocated to training (n = 136) and test (n = 68) sets. Postcontrast T1-weighted images, T2-weighted images, and fluid-attenuated inversion recovery images were analyzed to extract 250 radiomics features. Various machine learning classifiers were trained using the radiomics features to predict the glioma grade. The trained classifiers were internally validated on the institutional test set and externally validated on a separate cohort (n = 99) from The Cancer Genome Atlas (TCGA). Classifier performance was assessed by determining the area under the curve (AUC) from receiver operating characteristic curve analysis. An identical process was performed in the nonenhancing LGG subgroup (institutional training set, n = 73; institutional test set, n = 37; and TCGA cohort, n = 37) to predict the glioma grade.

Results

The performance of the best classifier was good in the internal validation set (AUC, 0.85) and fair in the external validation set (AUC, 0.72) to predict the LGG grade. For the nonenhancing LGG subgroup, the performance of the best classifier was good in the internal validation set (AUC, 0.82), but poor in the external validation set (AUC, 0.68).

Conclusion

Radiomics feature-based classifiers may be useful to predict LGG grades. However, radiomics classifiers may have a limited value when applied to the nonenhancing LGG subgroup in a TCGA cohort.

Frameless Stereotactic Brain Biopsies: Comparison of Minimally Invasive Robot-Guided and Manual Arm-Based Technique

BACKGROUND

Most brain biopsies are still performed with the aid of a navigation-guided mechanical arm. Due to the manual trajectory alignment without rigid skull contact, frameless aiming devices are prone to considerably lower accuracy.

OBJECTIVE

To compare a novel minimally invasive robot-guided biopsy technique with rigid skull fixation to a standard frameless manual arm biopsy procedure.

METHODS

Accuracy, procedural duration, diagnostic yield, complication rate, and cosmetic result were retrospectively assessed in 40 consecutive cases of frameless stereotactic biopsies and compared between a minimally invasive robotic technique using the iSYS1 guidance device (iSYS Medizintechnik GmbH) (robot-guided group [ROB], n = 20) and a manual arm-based technique (group MAN, n = 20).

RESULTS

Application of the robotic technique resulted in significantly higher accuracy at entry point (group ROB median 1.5 mm [0.4-3.2 mm] vs manual arm-based group (MAN) 2.2 mm [0.2-5.2 mm], P = .019) and at target point (group ROB 1.5 mm [0.4-2.8 mm] vs group MAN 2.8 mm [1.4-4.9 mm], P = .001), without increasing incision to suture time (group ROB 30.0 min [20-45 min vs group MAN 32.5 min [range 20-60 min], P = .09) and significantly shorter skin incision length (group ROB 16.3 mm [12.7-23.4 mm] vs group MAN 24.2 mm [18.0-37.0 mm], P = .008).

CONCLUSION

According to our data, the proposed technique of minimally invasive robot-guided brain biopsies can improve accuracy without increasing operating time while being equally safe and effective compared to a standard frameless arm-based manual biopsy technique.

Cytokine Microdialysis for Real-Time Immune Monitoring in Glioblastoma Patients Undergoing Checkpoint Blockade

BACKGROUND

Glioblastoma is the most common primary malignancy of the brain, with a dismal prognosis. Immunomodulation via checkpoint inhibition has provided encouraging results in non-CNS malignancies, but prediction of responders has proven to be challenging in glioblastoma patients.

OBJECTIVE

To determine the proportion of patients who have a measurable increase of interferon gamma levels in brain tumor tissue after their first dose of nivolumab, and to evaluate the safety of using brain tumor microdialysis to monitor for immune response while evaluating the safety of the combination of anti-programmed death 1 (PD-1) and anti-lymphocyte activation gene 3 (LAG-3) checkpoint inhibition.

METHODS

The study design is a single-center, nonrandomized phase 1 clinical trial. Up to 15 adult patients with recurrent glioblastoma will be enrolled with the goal of 10 patients completing the trial over an anticipated 18 mo. Patients will undergo biopsy; placement of microdialysis catheters and lumbar drains; treatment with anti-PD-1 checkpoint inhibition; comprehensive immune biomarker collection; tumor resection; and then treatment with anti-PD-1 and anti-LAG-3 checkpoint inhibition until progression.

EXPECTED OUTCOMES

We expect interferon gamma levels to increase in the brain as measured via microdialysis in treated patients. Based on published reports, microdialysis in this patient population is expected to be safe, and anti-LAG-3 and anti-PD-1 combined will likely have a similar side effect profile to other checkpoint inhibitor combinations.

DISCUSSION

The failure of recent trials of immune therapies in glioblastoma underscores the need to appropriately measure response in the treated tissue. This trial may provide insight on indicators of which patients will respond to immune therapy.

Theranostic OCT microneedle for fast ultrahigh-resolution deep-brain imaging and efficient laser ablation in vivo

Current minimally invasive optical techniques for in vivo deep-brain imaging provide a limited resolution, field of view, and speed. These limitations prohibit direct assessment of detailed histomorphology of various deep-seated brain diseases at their native state and therefore hinder the potential clinical utilities of those techniques. Here, we report an ultracompact (580 μm in outer diameter) theranostic deep-brain microneedle combining 800-nm optical coherence tomography imaging with laser ablation. Its performance was demonstrated by in vivo ultrahigh-resolution (1.7 μm axial and 5.7 μm transverse), high-speed (20 frames per second) volumetric imaging of mouse brain microstructures and optical attenuation coefficients. Its translational potential was further demonstrated by in vivo cancer visualization (with an imaging depth of 1.23 mm) and efficient tissue ablation (with a 1448-nm continuous-wave laser at a 350-mW power) in a deep mouse brain (with an ablation depth of about 600 μm).

Auditory and Visual User Interface for Optical Guidance During Stereotactic Brain Tumor Biopsies

During stereotactic brain tumor biopsies, the detection of protoporphyrin IX (PpIX) fluorescence and microvascular perfusion using laser Doppler flowmetry (LDF) with a handheld fiber optic probe allows the identification of tumor tissue while decreasing the risk of intracranial hemorrhage. Neurosurgeons performing this procedure usually view the measurement values on a screen. When their visual focus is directed at the surgical site, they require an assistant to verbally relay the values. An auditory and visual user interface (UI), which displays measurement values accurately and allows fast and intuitive signal recognition, can improve this procedure. This paper experimentally evaluates an auditory and visual UI for providing real-time measurement feedback during stereotactic brain tumor biopsies. In a user study (n = 15), the accuracy of auditory and visual response was determined using function response tests, and user acceptance was evaluated. The auditory signals proved to be intuitive and easy to recognize and remember. The visual display of measurement values was easy to understand and facilitated the user's decision-making process. Moreover, the UI exhibited high user acceptance.

Complications after frame-based stereotactic brain biopsy: a systematic review

Stereotactic frame-based brain biopsy is one of the most used procedures to obtain brain tissue. This procedure is usually considered as mini-invasive, quick, efficient, and safe even if results of the different studies are widely heterogenous. The objective of this review of the literature is to describe and analyze the complications of stereotactic frame-based brain biopsy. About 132 articles were found after a research in the Medline database. We only considered English references published between 1994 and June 2019. Additional studies were found by using the references from articles identified in the original search. This systematic review was conducted according to PRISMA guidelines. After applying exclusion criteria, we eventually considered 25 relevant studies. The mortality rate varies from 0.7 to 4%. Overall morbidity ranges from 3 to 13%. Most of the complications are revealed by the following symptoms: neurological impairment (transient or permanent), seizure, and unconsciousness. Symptomatic hemorrhage range varies from 0.9 to 8.6%, whereas considering asymptomatic bleeding, the range may be up to 59.8%. Complications were clinically evident within minutes to a few hours after the biopsy. Corrective surgeries are very rare (< 1%). Complications occurring after a frame-based stereotactic brain biopsy are rare but with serious side effects. It rarely leads to death or to permanent neurological impairment. Description and classification of complications are often heterogeneous in the literature. The use of a grading scale could help comparisons between series from around the world. Future studies should establish a score that allows neurosurgeon to predict post-biopsy complications.

Robotic Stereotaxy in Cranial Neurosurgery: A Qualitative Systematic Review

BACKGROUND

Modern-day stereotactic techniques have evolved to tackle the neurosurgical challenge of accurately and reproducibly accessing specific brain targets. Neurosurgical advances have been made in synergy with sophisticated technological developments and engineering innovations such as automated robotic platforms. Robotic systems offer a unique combination of dexterity, durability, indefatigability, and precision.

OBJECTIVE

To perform a systematic review of robotic integration for cranial stereotactic guidance in neurosurgery. Specifically, we comprehensively analyze the strengths and weaknesses of a spectrum of robotic technologies, past and present, including details pertaining to each system's kinematic specifications and targeting accuracy profiles.

METHODS

Eligible articles on human clinical applications of cranial robotic-guided stereotactic systems between 1985 and 2017 were extracted from several electronic databases, with a focus on stereotactic biopsy procedures, stereoelectroencephalography, and deep brain stimulation electrode insertion.

RESULTS

Cranial robotic stereotactic systems feature serial or parallel architectures with 4 to 7 degrees of freedom, and frame-based or frameless registration. Indications for robotic assistance are diversifying, and include stereotactic biopsy, deep brain stimulation and stereoelectroencephalography electrode placement, ventriculostomy, and ablation procedures. Complication rates are low, and mainly consist of hemorrhage. Newer systems benefit from increasing targeting accuracy, intraoperative imaging ability, improved safety profiles, and reduced operating times.

CONCLUSION

We highlight emerging future directions pertaining to the integration of robotic technologies into future neurosurgical procedures. Notably, a trend toward miniaturization, cost-effectiveness, frameless registration, and increasing safety and accuracy characterize successful stereotactic robotic technologies.

Safe Placement of Ommaya Reservoirs in Thrombocytopenic Patients: One Institutions Experience

Objective The purpose of this study was to assess the risk of hemorrhagic complications in thrombocytopenic patients after Ommaya reservoir placement. Methods Between 2009 and 2017, 192 patients were identified on the National Neoplastic Meningitis Registry and had undergone Ommaya reservoir placement for intrathecal chemotherapy. A retrospective chart review was performed to collect the preoperative and postoperative platelet levels, whether or not the patient received any transfusion of platelets, neurological exams, and whether a postoperative head CT was obtained. Using generally accepted recommendations, a platelet level less than 100,000/μL was considered clinically significant and used as our threshold for thrombocytopenia. Results Seven patients (3.6%) were identified as thrombocytopenic in our patient population with platelet counts ranging from 54,000 to 99,000/μL. Primary diagnoses for the seven patients included leukemia, prostate cancer, primary brain cancer (four patients), and lung cancer (non-small-cell lung carcinoma). One patient received platelet transfusions preoperatively. Three patients had a routine head CT obtained postoperatively with no abnormal findings noted. There were no changes in the neurological exam noted in all of the patients included in this study. No clinically significant hemorrhages were identified in our patients. Conclusions From our single institutional experience, we found that thrombocytopenia is fairly uncommon, found in only 3.6% of our patients undergoing placement of Ommaya reservoirs. We did not encounter any increased risks of postoperative hemorrhage in studied thrombocytopenic patients.

Interstitial imaging with multiple diffusive reflectance spectroscopy projections for in vivo blood vessels detection during brain needle biopsy procedures

Blood vessel injury during image-guided brain biopsy poses a risk of hemorrhage. Approaches that reduce this risk may minimize related patient morbidity. We present here an intraoperative imaging device that has the potential to detect the brain vasculature in situ. The device uses multiple diffuse reflectance spectra acquired in an outward-viewing geometry to detect intravascular hemoglobin, enabling the construction of an optical image in the vicinity of the biopsy needle revealing the proximity to blood vessels. This optical detection system seamlessly integrates into a commercial biopsy system without disrupting the neurosurgical clinical workflow. Using diffusive brain tissue phantoms, we show that this device can detect 0.5-mm diameter absorptive carbon rods up to ∼ 2    mm from the biopsy window. We also demonstrate feasibility and practicality of the technique in a clinical environment to detect brain vasculature in an in vivo model system. In situ brain vascular detection may add a layer of safety to image-guided biopsies and minimize patient morbidity.

Stereotactic brain biopsy: evaluation of robot-assisted procedure in 60 patients

BACKGROUND

Frameless stereotactic biopsies, particularly robot-assisted procedures are increasing in neurosurgery centers. Results of these procedures should be at least equal to or greater than frame-based reference procedure. Evaluate robot-assisted technology is necessary in particular, when a team has chosen to switch from one to another method.

OBJECTIVE

The objective of our prospective work was (i) to evaluate the success rate of contributive robotic-assisted biopsy in 60 patients, to report the morbidity and mortality associated with the procedure and (ii) to compare it with literature data.

METHODS

We performed a prospective and descriptive study including 60 consecutive patients having had robotic-assisted stereotactic biopsy at the Rouen University Hospital, France. All patients had presurgical imaging before the procedure included Magnetic Resonance Imaging merged with Computed Tomography scan acquisition. Registration was mostly performed with a touch-free laser (57/60). A control Computed Tomography scan was always realized at day 0 or day 1 after surgery. Data collected were success rate, bleeding, clinical worsening, infection, and mortality.

RESULTS

All the biopsies were considered as contributive and lead to the final diagnosis. In 41/60 patients (68%), the lesion was glial. Six in 60 patients (10%) had visible bleeding without clinical worsening related, 5/60 patients (8.5%) showed clinical impairment following surgery, which was permanent in 2 patients, and 1/60 patient presented generalized seizures. We did not report any infection and mortality.

CONCLUSION

Robot-assisted frameless surgery is efficient and provides a reasonable alternative to frame-based procedure. The operating time can be reduced, without increasing morbidity and mortality rates.

A novel robot-guided minimally invasive technique for brain tumor biopsies

OBJECTIVE

As decisions regarding tumor diagnosis and subsequent treatment are increasingly based on molecular pathology, the frequency of brain biopsies is increasing. Robotic devices overcome limitations of frame-based and frameless techniques in terms of accuracy and usability. The aim of the present study was to present a novel, minimally invasive, robot-guided biopsy technique and compare the results with those of standard burr hole biopsy.

METHODS

A tubular minimally invasive instrument set was custom-designed for the iSYS-1 robot-guided biopsies. Feasibility, accuracy, duration, and outcome were compared in a consecutive series of 66 cases of robot-guided stereotactic biopsies between the minimally invasive (32 patients) and standard (34 patients) procedures.

RESULTS

Application of the minimally invasive instrument set was feasible in all patients. Compared with the standard burr hole technique, accuracy was significantly higher both at entry (median 1.5 mm [range 0.2-3.2 mm] vs 1.7 mm [range 0.8-5.1 mm], p = 0.008) and at target (median 1.5 mm [range 0.4-3.4 mm] vs 2.0 mm [range 0.8-3.9 mm], p = 0.019). The incision-to-suture time was significantly shorter (median 30 minutes [range 15-50 minutes] vs 37.5 minutes [range 25-105 minutes], p < 0.001). The skin incision was significantly shorter (median 16.3 mm [range 12.7-23.4 mm] vs 28.4 mm [range 20-42.2 mm], p = 0.002). A diagnostic tissue sample was obtained in all cases.

CONCLUSIONS

Application of the novel instrument set was feasible in all patients. According to the authors' data, the minimally invasive robot-guidance procedure can significantly improve accuracy, reduce operating time, and improve the cosmetic result of stereotactic biopsies.

Frame-based stereotactic biopsies using an intraoperative MR-scanner are as safe and effective as conventional stereotactic procedures

Background

Frame-based stereotactic biopsy (FBSB) is a minimally-invasive and effective procedure for the diagnosis of brain lesions and will likely gain clinical importance. Since FBSB procedures comprise a variety of imaging and sampling methods, it is necessary to compare the safety and effectiveness of individual techniques.

Objective

To assess the safety and effectiveness of FBSB using 1.5T iMRI as a one-stop procedure under general anesthesia without intraoperative histological examination.

Methods

In this single-center, retrospective analysis, 500 consecutive FBSBs using iMRI were compared to a historic control of 100 biopsies with traditional workflows (computed tomography (CT) with MRI image fusion). All procedures were performed under general anesthesia. Data on surgical procedures, pre- and postoperative neurologic patient status, complications and diagnostic yield were extracted from clinical records.

Results

Complication rates and diagnostic yield showed no significant differences between both groups. Mortality was 0.6%, 95% CI = [0.12%, 1.74%], in the iMRI and 0.0% [0.00%, 3.62%], in the control group with a morbidity of 5.4% [3.6%, 7.8%] and 6.0% [2.2%, 12.6%] and a diagnostic yield of 96.8% [94.9%, 98.2%] and 96.0% [90.1%, 98.9%]. Mean procedure duration was 124 [121, 127] minutes using iMRI and 112 [106, 118] minutes in the control group.

Conclusion

FBSB using 1.5T iMRI under general anesthesia is a safe and effective procedure and is equivalent to traditional stereotactic workflows with respect to complication rate and diagnostic yield.

FET PET in the evaluation of indeterminate brain lesions on MRI: Differentiating glioma from other non-neoplastic causes - A pilot study

We aimed to determine the utility of FET PET in the management of indeterminate CNS lesions found on MRI. We performed a retrospective analysis of patients with FET PET at a single tertiary institution from 2011 to 2015. FET PET images were processed using usual methods and measurements taken including SUVmax, TBRmax, and analysis of dynamic series where available (Kipeak, Vdpeak, as well as tumor:background ratio for these variables). Correlation studies were performed using ANOVA between cohorts of high-grade histology, low-grade histology, and benign histology/stable on observation. Thirty-five patients were included, of whom 34 were suitable for analysis with median follow-up of 5 months. The positive predictive value of FET PET in this cohort was 83.3%. FET SUVmax differentiated between patients with high-grade (mean SUV 3.38, 95% CI 2.21-4.55), low-grade (1.88, 95% CI 1.33-2.43) and benign/observation (1.42, 95% CI 1.13-1.71) cohorts (p = 0.0003). Similarly, tumour to brain ratio was significant (p < 0.0001). Kipeak distinguished between high grade and observation cohorts (p = 0.036), as did KiTBR (p = 0.025). Vd peak was not significantly different in these two cohorts (p = 0.057) but Vd TBR was (p = 0.041). In conclusion, FET PET demonstrated a high positive predictive value for glioma in patients with indeterminate brain lesions on MRI. The combination of negative FET and negative FDG PET scans may predict an indolent clinical course. Confirmatory trials are needed to establish the potential value of FET PET in guiding surgical management in this cohort.

Outcome of single-trajectory rigid endoscopic third ventriculostomy and biopsy in the management algorithm of pineal region tumors: a case series and review of the literature

BACKGROUND

Tumors within the pineal region represent 1.5 to 8.5% of the pediatric brain tumors and 1.2% of all brain tumors. A management algorithm has been proposed in several publications. The algorithm includes endoscopic third ventriculostomy (ETV) and biopsy in cases presenting with hydrocephalus. In this series, we are presenting the efficacy of a single-trajectory approach for both ETV and biopsy.

METHODS

Eleven cases were admitted to Alexandria main university hospital from 2013 to 2016 presenting with pineal region tumors and hydrocephalus. Mean age at diagnosis was 11 years (1-27 years). All cases had ETV and biopsy using rigid ventriculoscope through a single trajectory from a burr hole planned on preoperative imaging. Follow-up period was 7-48 months.

RESULTS

All 11 cases presented with hydrocephalus and increased intracranial pressure manifestations. Histopathological diagnosis was successful in 9 out of 11 cases (81.8%). Three cases were germ-cell tumors, two cases were pineoblastomas, two cases were pilocytic astrocytomas, and two cases were grade 2 tectal gliomas. Five of the ETV cases (45.5%) failed and required VPS later on. Other complications of ETV included one case of intraventricular hemorrhage and a case with tumor disseminated to the basal cisterns.

CONCLUSION

In our series, we were able to achieve ETV and biopsy through a single trajectory and a rigid endoscope with results comparable to other studies in the literature.

5-ALA fluorescence and laser Doppler flowmetry for guidance in a stereotactic brain tumor biopsy

A fiber optic probe was developed for guidance during stereotactic brain biopsy procedures to target tumor tissue and reduce the risk of hemorrhage. The probe was connected to a setup for the measurement of 5-aminolevulinic acid (5-ALA) induced fluorescence and microvascular blood flow. Along three stereotactic trajectories, fluorescence (n = 109) and laser Doppler flowmetry (LDF) (n = 144) measurements were done in millimeter increments. The recorded signals were compared to histopathology and radiology images. The median ratio of protoporphyrin IX (PpIX) fluorescence and autofluorescence (AF) in the tumor was considerably higher than the marginal zone (17.3 vs 0.9). The blood flow showed two high spots (3%) in total. The proposed setup allows simultaneous and real-time detection of tumor tissue and microvascular blood flow for tracking the vessels.

Preoperative assessment of haemostasis in patients undergoing stereotactic brain biopsy

Parenchymal hemorrhage is considered a major risk factor for perioperative morbidity in patients undergoing stereotactic brain biopsy. Studies on patients undergoing surgical procedures have suggested that evaluation of prothrombin time (PT) and activated partial thromboplastin time (aPTT) is of limited value with regard to prevention of haemorrhagic complications. However, this issue has not yet been addressed in patients undergoing stereotactic biopsy of intracranial lesions. We retrospectively analysed the medical records of 159 consecutive patients undergoing stereotactic biopsy of supratentorial intracranial lesions during a three-year period. Laboratory values (PT, aPTT, platelet count) were reviewed as well as clinical characteristics, modalities of surgical treatment, histopathological results and the postoperative course of patients. The overall diagnostic yield was 93.7%. Histopathological examination revealed glioma (WHO°I: 5, WHO°II: 25, WHO°III: 23, WHO°IV: 65), lymphoma (n = 14), inflammation (n = 8) and other entities (n = 6). Surgery-associated neurological deficits occurred in 7 patients (4.4%) and completely resolved in 6 of these patients. CT-confirmed intracranial hemorrhage occurred in 2 patients (1.3%) and in both cases, histopathological examination revealed glioblastoma. Results of hemostatic parameters (PT: 99 ± 13%, aPTT: 24 ± 3s, platelet count: 274 ± 87 10³/μL) were within normal range values in all patients and did not correlate with postsurgical morbidity. Standard assessment of haemostasis seems to be of limited value in patients with intracranial lesions undergoing stereotactic biopsy. Further studies regarding the intratumoural vasculature's impact on the risk of biopsy-related bleeding are necessary.

Epigenetic Modifications as Biomarkers of Tumor Development, Therapy Response, and Recurrence across the Cancer Care Continuum

Aberrant epigenetic modifications are an early event in carcinogenesis, with the epigenetic landscape continuing to change during tumor progression and metastasis—these observations suggest that specific epigenetic modifications could be used as diagnostic and prognostic biomarkers for many cancer types. DNA methylation, post-translational histone modifications, and non-coding RNAs are all dysregulated in cancer and are detectable to various degrees in liquid biopsies such as sputum, urine, stool, and blood. Here, we will focus on the application of liquid biopsies, as opposed to tissue biopsies, because of their potential as non-invasive diagnostic tools and possible use in monitoring therapy response and progression to metastatic disease. This includes a discussion of septin-9 (SEPT9) DNA hypermethylation for detecting colorectal cancer, which is by far the most developed epigenetic biomarker assay. Despite their potential as prognostic and diagnostic biomarkers, technical issues such as inconsistent methodology between studies, overall low yield of epigenetic material in samples, and the need for improved histone and non-coding RNA purification methods are limiting the use of epigenetic biomarkers. Once these technical limitations are overcome, epigenetic biomarkers could be used to monitor cancer development, disease progression, therapeutic response, and recurrence across the entire cancer care continuum.

Accuracy of Raman spectroscopy in differentiating brain tumor from normal brain tissue

Raman spectroscopy could be applied to distinguish tumor from normal tissues. This meta-analysis was conducted to assess the accuracy of Raman spectroscopy in differentiating brain tumor from normal brain tissue. PubMed and Embase were searched to identify suitable studies prior to Jan 1st, 2016. We estimated the pooled sensitivity, specificity, positive and negative likelihood ratios (LR), diagnostic odds ratio (DOR), and constructed summary receiver operating characteristics (SROC) curves to identity the accuracy of Raman spectroscopy in differentiating brain tumor from normal brain tissue. A total of six studies with 1951 spectra were included. For glioma, the pooled sensitivity and specificity of Raman spectroscopy were 0.96 (95% CI 0.94-0.97) and 0.99 (95% CI 0.98-0.99), respectively. The area under the curve (AUC) was 0.9831. For meningioma, the pooled sensitivity and specificity were 0.98 (95% CI 0.94-1.00) and 1.00 (95% CI 0.98-1.00), respectively. The AUC was 0.9955. This meta-analysis suggested that Raman spectroscopy could be an effective and accurate tool for differentiating glioma and meningioma from normal brain tissue, which would help us both avoid removal of normal tissue and minimize the volume of residual tumor.

Laser Doppler sensing for blood vessel detection with a biologically inspired steerable needle

Puncturing blood vessels during percutaneous intervention in minimally invasive brain surgery can be a life threatening complication. Embedding a forward looking sensor in a rigid needle has been proposed to tackle this problem but, when using a rigid needle, the procedure needs to be interrupted and the needle extracted if a vessel is detected. As an alternative, we propose a novel optical method to detect a vessel in front of a steerable needle. The needle itself is based on a biomimetic, multi-segment design featuring four hollow working channels. Initially, a laser Doppler flowmetry probe is characterized in a tissue phantom with optical properties mimicking those of human gray matter. Experiments are performed to show that the probe has a 2.1 mm penetration depth and a 1 mm off-axis detection range for a blood vessel phantom with 5 mm s^-1 flow velocity. This outcome demonstrates that the probe fulfills the minimum requirements for it to be used in conjunction with our needle. A pair of Doppler probes is then embedded in two of the four working channels of the needle and vessel reconstruction is performed using successive measurements to determine the depth and the off-axis position of the vessel from each laser Doppler probe. The off-axis position from each Doppler probe is then used to generate a 'detection circle' per probe, and vessel orientation is predicted using tangent lines between the two. The vessel reconstruction has a depth root mean square error (RMSE) of 0.3 mm and an RMSE of 15° in the angular prediction, showing real promise for a future clinical application of this detection system.