Spectroscopy-supported frame-based image-guided stereotactic biopsy of parenchymal brain lesions: Comparative evaluation of diagnostic yield and diagnostic accuracy

Computed tomography-guided frame-based stereotactic brain biopsy of non-enhancing lesions using indirect evidence of target selection, technical consideration, and early clinical experience

Background

The objective was to study the effectiveness and diagnostic outcome of frame-based stereotactic brain biopsy (STB) done for contrast non-enhancing lesions using indirect evidence of target selection observed in a plain computed tomography (CT) scan of the head.

Methods

Data of patients with contrast non-enhancing brain lesions who underwent STB are collected retrospectively from NIMHANS Bangalore, hospital neurosurgery database from January 2021 to March 2023. Those cases subjected to plain CT scans after fixing the stereotactic frame to the head were included in the study. A final histopathological report analysis of these cases was done to assess the diagnostic accuracy.

Results

A total of 27 such cases were biopsied. The mean age of subjects was 44.04 ± 17.812 years. Most subjects were in the age group 31-40 years (29.6%). About 55.6% were male and 44.4% were female. The most common site of biopsy was the frontal lobe. The most common indirect evidence on CT was perilesional edema at 33.3% and periventricular location at 33.3%, followed by intralesional calcification at 11.1%. Our diagnostic accuracy was 92.59%. The asymptomatic hemorrhage rate was 2%, and an increase in perilesional edema was seen in 2% of cases.

Conclusion

Indirect targeting is a safe and intuitive method for biopsy of contrast non-enhancing lesions. Due consideration is to be given to various findings visible in non-contrast CT scans of the head as indirect evidence of target selection while performing frame-based STB of contrast non-enhancing lesions. This method will also be helpful in resource-limited centers, especially in low-income countries.

Clinical outcomes as a function of the number of samples taken during stereotactic needle biopsies: a meta-analysis

BACKGROUND

Stereotactic needle biopsy remains the cornerstone for tissue diagnosis for tumors located in regions of the brain that are difficult to access through open surgery.

OBJECTIVE

We perform a meta-analysis of the literature to examine the relation between number of samples taken during biopsy and diagnostic yield, morbidity and mortality.

METHODS

We identified 2416 patients from 28 cohorts in studies published in PubMed database that studied stereotactic needle biopsies for tumor indications. Meta-analysis by proportions and meta-regression analyses were performed.

RESULTS

On meta-analysis, the morbidity profile of the published needle biopsy studies clustered into three groups: studies that performed < 3 samples (n = 8), 3-6 samples (n = 13), and > 6 samples during biopsy (n = 7). Pooled estimates for biopsy related morbidity were 4.3%, 16.3%, and 17% for studies reporting < 3, 3-6, and > 6 biopsy samples, respectively. While these morbidity estimates significantly differed (p < 0.001), the diagnostic yields reported for studies performing < 3 biopsies, 3-6 samples, and > 6 samples were comparable. Pooled estimates of diagnostic yield for these three groups were 90.4%, 93.8%, and 88.1%, respectively. Mortality did not significantly differ between studies reporting differing number of samples taken during biopsy.

CONCLUSIONS

Our meta-analysis suggests that morbidity risk in needle biopsy is non-linearly associated with the number of samples taken. There was no association between the number of biopsies taken, and diagnostic yield or mortality.

The utility of magnetic resonance spectroscopy in frame-less stereotactic needle biopsy of glioma

OBJECTIVE

Proton magnetic resonance spectroscopy (¹H-MRS) can benefit the differentiation of gliomas preoperative grading and facilitate guiding biopsy. This study was to investigate the optimal metabolite or metabolic ratios of MRS for the biopsy target delineating by using the technique of MRS imaging guided frame-less stereotactic biopsy.

METHODS

During a 4 year period between the Sep 2012 and Oct 2016, 57 patients (25 women, 32 men; mean age, 46.4) with histologic diagnosis of glioma, who underwent the ¹H-MRS imaging guided frameless stereotactic biopsy, were retrospectively reviewed. The metabolite or metabolic ratios values of MRS was measured. And the sensitivity, specificity, accuracy as well as the area under the curve (AUC) of those parameters for glioma grading are calculated based on the receiver operating characteristic curve (ROC) analysis.

RESULTS

65 stereotactic biopsy samples from 57 patients were histopathologically clarified to HGGs (25) or LGGs (40) for quantitative analysis. The Cho, Cho/NAA and Cho/Cr values of LGGs group were significantly lower than that of HGGs (P = 0.09, 0.001, 0.003), and the NAA value of LGGs group was significantly higher than that of HGGs (P = 0.001). The cutoff value of 3.65 for the Cho/NAA ratio provided the best combination of sensitivity (92.0%), specificity (95.0%), and diagnostic accuracy (93.8%) for identifying glioma grade, which was superior to other parameters.

CONCLUSION

The results of our study provided evidence that Cho/NAA ratio had the superior diagnostic performance in distinguishing glioma grade, indicating that the spot of highest Cho/NAA ratio was optimal metabolic targets for spectroscopic guided tissue sampling in homogenous glioma.

Current Trends for Improving Safety of Stereotactic Brain Biopsies: Advanced Optical Methods for Vessel Avoidance and Tumor Detection

Stereotactic brain needle biopsies are indicated for deep-seated or multiple brain lesions and for patients with poor prognosis in whom the risks of resection outweigh the potential outcome benefits. The main goal of such procedures is not to improve the resection extent but to safely acquire viable tissue representative of the lesion for further comprehensive histological, immunohistochemical, and molecular analyses. Herein, we review advanced optical techniques for improvement of safety and efficacy of stereotactic needle biopsy procedures. These technologies are aimed at three main areas of improvement: (1) avoidance of vessel injury, (2) guidance for biopsy acquisition of the viable diagnostic tissue, and (3) methods for rapid intraoperative assessment of stereotactic biopsy specimens. The recent technological developments in stereotactic biopsy probe design include the incorporation of fluorescence imaging, spectroscopy, and label-free imaging techniques. The future advancements of stereotactic biopsy procedures in neuro-oncology include the incorporation of optical probes for real-time vessel detection along and around the biopsy needle trajectory and in vivo confirmation of the diagnostic tumor tissue prior to sample acquisition.

Neuroendoscopic Intraoperative Ultrasound-Guided Technique for Biopsy of Paraventricular Tumors

Different tumors can be encountered in the paraventricular regions, and whereas their deep location often make them difficult to access surgically, they may be amenable to chemotherapy and/or radiotherapy. Therefore, tumor biopsy and histologic diagnosis are mandatory to optimize treatment. Different technical procedures have been recommended; the neuroendoscopic approach is accepted and widely used, in particular with an enlarged ventricular system. However, specifically with paraventricular tumors, tissue sampling may be challenging. In such a scenario, the use of intraoperative ultrasonography technique can add some advantages regarding diagnostic accuracy and procedure safety. Accordingly, in this study we describe a novel technical procedure in 7 selected patients in whom tumor tissue biopsy was performed in a coupled neuroendoscopic and ultrasound-guided environment. We define a neuroendoscopic intraoperative ultrasound technique. The main advantages of this technique are the identification of the tumor that may not been clearly identified underneath the ventricular ependymal through the neuroendoscopic window alone, and furthermore, that this technique gives the possibility to detect the depth of the needle advance∖ment in the selected tissue while labeling the lesion beneath the ventricular ependyma. Moreover, intraoperative ultrasonography can reveal in a real-time fashion intracranial hemorrhages that may occur after tissue biopsy, therefore providing a useful tool to achieve valid and directed hemostasis when needed.

Surgical Management of Incidental Gliomas

Detailed brain imaging studies discover gliomas incidentally before clinical symptoms or signs show. These tumors represent an early stage in the natural history of gliomas. Left untreated, they are likely to progress to a symptomatic stage and transform to malignant gliomas. A greater extent of resection delays the onset of malignant transformation and prolongs patient survival. Because incidental gliomas are typically smaller and less likely to be in eloquent brain locations, there is a strong case for early surgical intervention to maximize resection and improve outcomes. This article discusses developments in the surgical management of low-grade gliomas.

Neuronavigation-assisted trajectory planning for deep brain biopsy with susceptibility-weighted imaging

BACKGROUND

Susceptibility-weighted imaging (SWI) exploits susceptibility differences between tissues to enhance contrast in magnetic resonance imaging to enable the visualization of small blood vessels that are difficult to detect by other contrast agents. This study explored the value of SWI-based planning for neuronavigation-guided deep brain biopsies to reduce the incidence of post-surgical complications.

METHODS

The cohort of 84 patients was divided into 41 biopsies performed aided by SWI (SWI group) and 43 biopsies based on conventional T1w-Gd-based imaging (T1w-Gd group). Biopsy targets were determined using magnetic resonance spectroscopy (MRS) before the operation, and the safest trajectory was selected based on preoperative images of blood vessels.

RESULTS

Within 24 h of surgery, there was no radiographically identified bleeding, no blood extravasation and no clinical intracranial hypertension in the SWI group. Only one patient (2.5 %) with basal ganglia lymphoma developed transient hemiparesis after biopsy, who later recovered after undergoing symptomatic treatment. Complication rates in the SWI group were lower than in the T1w-Gd group, where a 7 % morbidity rate was encountered with one patient developing a permanent neurological deficit and two showing biopsy-associated hemorrhages. SWI imaging yielded a better visualization of subcortical vessels and deep-seated brain structures.

CONCLUSIONS

SWI-based imaging revealed significantly better visualization of small-caliber vasculature that was not detectable on conventional T1w-Gd imaging, minimizing damage to the brain and reducing postoperative complications. Furthermore, MRS can contribute significantly to target selection to improve the yield of image-guided biopsies.

The role of surgery in grade II/III oligodendroglial tumors

Supratentorial gliomas WHO grade II and III with an oligodendroglial phenotype are highly infiltrative lesions that preferentially originate in lobar location. Open tumor resection represents one of the mainstays of management as beneficial decompressive effects for large space-occupying lesions and oncologically relevant cytoreductive effects from complete resection can be expected. In patients not eligible for safe tumor resection meticulous histological and molecular-genetic evaluation can be obtained from advanced stereotactic biopsy techniques. In this perspective, important aspects of open tumor surgery and stereotactic biopsy are discussed within the context of diagnosis, prognosis and treatment of oligodendrogliomas and oligoastrocytomas WHO grade II and III. Practical considerations are provided in order to integrate the place of surgery into an increasingly personalized management concept. For highly selected patients interstitial brachytherapy is introduced as an alternative surgically performed treatment option.

The clinical utility of multimodal MR image-guided needle biopsy in cerebral gliomas

PURPOSE

Our aim was to evaluate the diagnostic value of multimodal Magnetic Resonance (MR) Image in the stereotactic biopsy of cerebral gliomas, and investigate its implications.

MATERIALS AND METHODS

Twenty-four patients with cerebral gliomas underwent (1)H Magnetic Resonance Spectroscopy ((1)H-MRS)- and intraoperative Magnetic Resonance Imaging (iMRI)-supported stereotactic biopsy, and 23 patients underwent only the preoperative MRI-guided biopsy. The diagnostic yield, morbidity and mortality rates were analyzed. In addition, 20 patients underwent subsequent tumor resection, thus the diagnostic accuracy of the biopsy was further evaluated.

RESULTS

The diagnostic accuracies of biopsies evaluated by tumor resection in the trial groups were better than control groups (92.3% and 42.9%, respectively, p = 0.031). The diagnostic yield in the trial groups was better than the control groups, but the difference was not statistically significant (100% and 82.6%, respectively, p = 0.05). The morbidity and mortality rates were similar in both groups.

CONCLUSIONS

Multimodal MR image-guided glioma biopsy is practical and valuable. This technique can increase the diagnostic accuracy in the stereotactic biopsy of cerebral gliomas. Besides, it is likely to increase the diagnostic yield but requires further validation.

Recognition of anaplastic foci within low-grade gliomas using MR spectroscopy

BACKGROUND

The recognition of anaplastic foci within low-grade gliomas is of extreme importance in patients under follow-up for Grade II gliomas. We present the algorithm of MR spectroscopy (MRS)-guided brain biopsy and its correlation with tumour histology.

METHODS

Twenty-seven patients harbouring suspected Grade II/III glioma were examined on our 3T MR. 2D PRESS-CSI metabolite images of Choline/Creatine, Creatine/N-acetylaspartate and Choline/N-acetylaspartate were calculated and exported to the DICOM format. According to these maps, a stereobiopsy was performed at the point of maximum Choline/Creatine ratio prior to tumour resection. In the case of enhancing tumour, a subsequent biopsy was performed from the point of enhancement. Comparisons were made between the histology of the biopsied specimens and the resected tumours.

RESULTS

Eleven tumours were diagnosed as high-grade and sixteen as low-grade lesions. The correlation between main spectroscopic ratios (Cho/Cr and Cho/NAA) was strongly positive at the points of maximum Cho/Cr. Similar results were obtained at the points of contrast enhancement. Comparison of histological parameters of biopsy samples at the points of maximum Cho/Cr and histological examination of the completely resected tumours gives a strong correlation of tumour grade, number of mitoses and Ki-67 expression. The diagnostic accuracy of MRS-guided biopsy was 84%. The absolute value of Cho/NAA was higher in high-grade compared to that of low-grade lesions. The value of Cho/NAA ratio of 0.9 using MRS produced a sensitivity and specificity of 78% in the differentiation between low-grade and high-grade lesions. Combining MRS with structural MR, the sensitivity increased to 86% and the specificity to 80%.

CONCLUSIONS

Strong correlation was demonstrated between Cho/Cr and Ch/NAA ratios. Strong correlation was demonstrated between histological parameters of biopsy samples taken using Cho/Cr ratio and those from total tumour examination. Diagnostic accuracy of MRS-guided biopsy was 84%. Sensitivity and specificity of MRS combined with structural MR reaches 86% and 80%.

Diagnostic yield of stereotactic needle-biopsies of sub-cubic centimeter intracranial lesions

Background:

Stereotactic brain biopsies are widely used for establishing the diagnosis of intracranial lesions. Here we examine whether stereotactic biopsy of smaller brain lesions, defined for this study as being less than 1 cubic centimeter (1 cc) in volume, are associated with lowered diagnostic yield.

Methods:

We conducted a retrospective analysis of 267 consecutive patients who underwent stereotactic brain biopsy between 2007 and 2011. Lesion volumes were calculated and were stratified by <1 or >1 cc.

Results:

A total of 13 of 246 (5.2%) biopsies for lesions >1 cc resulted in nondiagnostic tissue or an incorrect diagnosis. In contrast, 5 of 21 (23.8%) biopsies for <1 cc lesions yielded nondiagnostic or incorrect diagnosis. Posthoc review of tissue from the <1 cc lesions suggests the neuropathologist's expertise in the handling and analysis of limited specimen as a critical parameter of successful diagnosis. The operative morbidities were low for both the <1 and >1 cc biopsies (0% and 1%, respectively).

Conclusion:

This study demonstrates that stereotactic cerebral biopsy of lesions less than a cubic centimeter in volume results in a lower diagnostic yield versus larger lesions (76.2% versus 94.8%). While auxiliary measures may be taken to improve diagnostic yield, these patients may be best managed in a specialized center with experienced stereotactic neurosurgeons and neuropathologists.

Potential of MR spectroscopy for assessment of glioma grading

BACKGROUND

Magnetic resonance spectroscopy (MRS) is an imaging diagnostic method based that allows non-invasive measurement of metabolites in tissues. There are a number of metabolites that can be identified by standard brain proton MRS but only a few of them has a clinical significance in diagnosis of gliomas including N-acetylaspartate, choline, creatine, myo-inositol, lactate, and lipids.

METHODS

In this review, we describe potential of MRS for grading of gliomas.

RESULTS

Low-grade gliomas are generally characterized by a relatively high concentration of N-acetylaspartate, low level of choline and absence of lactate and lipids. The increase in creatine concentration indicates low-grade gliomas with earlier progression and malignant transformation. Progression in grade of a glioma is reflected in the progressive decrease in the N-acetylaspartate and myo-inositol levels on the one hand and elevation in choline level up to grade III on the other. Malignant transformation of the glial tumors is also accompanied by the presence of lactate and lipids in MR spectra of grade III but mainly grade IV gliomas. It follows that MRS is a helpful method for detection of glioma regions with aggressive growth or upgrading due to favorable correlation of the choline and N-acetylaspartate levels with histopathological proliferation index Ki-67. Thus, magnetic resonance spectroscopy is also a suitable method for the targeting of brain biopsies.

CONCLUSIONS

Gliomas of each grade have some specific MRS features that can be used for improvement of the diagnostic value of conventional magnetic resonance imaging in non-invasive assessment of glioma grade.

Increased frameless stereotactic accuracy with high-field intraoperative magnetic resonance imaging

BACKGROUND

Frameless stereotaxy commonly registers preoperative magnetic resonance imaging (MRI) to patients by using surface scalp anatomy or adhesive fiducial scalp markers. Patients' scalps may shift slightly between preoperative imaging and final surgical positioning with pinion placement, introducing error. This might be reduced when frameless stereotaxy is performed in a high-field intraoperative MRI (iMRI), as patients are positioned before imaging. This could potentially improve accuracy.

OBJECTIVE

To compare frameless stereotactic accuracy using a high-field iMRI with that using standard preoperative MRI.

METHODS

Data were obtained in 32 adult patients undergoing frameless stereotactic-guided brain tumor surgery. Stereotactic images were obtained with 1.5T MRI scanner either preoperatively (14 patients) or intraoperative (18 patients). System-generated accuracy measurements and distances from the actual center of each fiducial marker to that represented by neuronavigation were recorded. Finally, accuracy at multiple deep targets was assessed by using a life-sized human head stereotactic phantom in which fiducials were placed on deformable foam to mimic scalp.

RESULTS

: System-generated accuracy measurements were significantly better for the iMRI group (mean ± SEM = 1.04 ± 0.05 mm) than for the standard group (1.82 ± 0.09 mm; P < .001). Measured distances from the actual center of scalp fiducial markers to that represented by neuronavigation were also significantly smaller for iMRI (1.72 ± 0.10 mm) in comparison with the standard group (3.17 ± 0.22 mm; P < .001). Deep accuracy in the phantom model was significantly better with iMRI (1.67 ± 0.12 mm) than standard imaging (2.28 ± 0.14 mm; P = .003).

CONCLUSION

Frameless stereotactic accuracy is increased by using high-field iMRI compared with standard preoperative imaging.

Quantitative MR imaging and spectroscopy of brain tumours: a step forward?

OBJECTIVES

A prospective quantitative MR study of brain tumours was performed to show the potential of combining different MR techniques to distinguish various disease processes in routine clinical practice.

METHODS

Twenty-three patients with various intracranial tumours before treatment (diagnosis confirmed by a biopsy) and 59 healthy subjects were examined on a 3-T system by conventional MR imaging, 1H spectroscopic imaging, diffusion tensor imaging and T2 relaxometry. Metabolic concentrations and their ratios, T2 relaxation times and mean diffusivities were calculated and correlated on a pixel-by-pixel basis and compared to control data.

RESULTS

Different tumour types and different localisations revealed specific patterns of correlations between metabolic concentrations and mean diffusivity or T2 relaxation times. The patterns distinguish given tissue states in the examined area: healthy tissue, tissue infiltrated by tumour, active tumour, oedema infiltrated by tumour, oedema, etc. This method is able to describe the complexity of a highly heterogeneous tissue in the tumour and its vicinity, and determines crucial parameters for tissue differentiation.

CONCLUSIONS

A combination of different MR parameters on a pixel-by-pixel basis in individual patients enables better identification of the tumour type, direction of proliferation and assessment of the tumour extension.

KEY POINTS

• Magnetic resonance offers many different methods of examining the brain. • A combination of quantitative MR parameters helps distinguish different brain lesions • Different tumour types revealed specific correlation patterns amongst different MR parameters • The correlation patterns reflect highly heterogeneous complex tissue within tumours.

Low-grade gliomas in adults

In recent years, advances in the understanding of low-grade glioma (LGG) biology have driven new paradigms in molecular markers, diagnostic imaging, operative techniques and technologies, and adjuvant therapies. Taken together, these developments are collectively pushing the envelope toward improved quality of life and survival. In this article, the authors evaluate the recent literature to synthesize a comprehensive review of LGGs in the modern neurosurgical era.

Low-grade gliomas in adults

In recent years, advances in the understanding of low-grade glioma (LGG) biology have driven new paradigms in molecular markers, diagnostic imaging, operative techniques and technologies, and adjuvant therapies. Taken together, these developments are collectively pushing the envelope toward improved quality of life and survival. In this article, the authors evaluate the recent literature to synthesize a comprehensive review of LGGs in the modern neurosurgical era.

Towards improving the safety and diagnostic yield of stereotactic biopsy in a single centre

Background

Previously, we reported on our single centre results regarding the diagnostic yield of stereotactic needle biopsies of brain lesions. The yield then (1996–2006) was 89.4%. In the present study, we review and evaluate our experience with intraoperative frozen-section histopathologic diagnosis on-demand in order to improve the diagnostic yield.

Methods

One hundred sixty-four consecutive frameless biopsy procedures in 160 patients (group 1, 2006–2010) were compared with the historic control group (group 2, n = 164 frameless biopsy procedures). Diagnostic yield, as well as demographics, morbidity and mortality, was compared. Statistical analysis was performed by Student's t, Mann–Whitney U, Chi-square test and backward logistic regression when appropriate.

Results

Demographics were comparable. In group 1, a non-diagnostic tissue specimen was obtained in 1.8%, compared to 11.0% in group 2 (p = 0.001). Also, both the operating time and the number of biopsies needed were decreased significantly. Procedure-related mortality decreased from 3.7% to 0.6% (p = 0.121). Multivariate analysis only proved operating time (odds ratio (OR), 1.012; 95% confidence interval (CI), 1.000–1.025; p = 0.043), a right-sided lesion (OR, 3.183; 95% CI, 1.217–8.322; p = 0.018) and on-demand intraoperative histology (OR, 0.175; 95% CI, 0.050–0.618; p = 0.007) important factors predicting non-diagnostic biopsies.

Conclusions

The importance of a reliable pathological diagnosis as obtained by biopsy must not be underestimated. We believe that when performing stereotactic biopsy for intracranial lesions, next to minimising morbidity, one should strive for as high a positive yield as possible. In the present single centre retrospective series, we have shown that using a standardised procedure and careful on-demand intraoperative frozen-section analysis can improve the diagnostic yield of stereotactic brain biopsy procedures as compared to a historical series.

Stereotactic brain biopsy: Single center retrospective analysis of complications

OBJECTIVE

Stereotactic biopsy is a widely used surgical technique for the histological diagnosis of intracranial lesions. Potential risks of this procedure, such as hemorrhage, seizure, and infection have been established, and different risk factors have been characterized. However, these risks have been addressed by only few studies conducted in Asian countries.

MATERIALS AND METHODS

The study group is comprised of 299 consecutive stereotactic biopsy procedures by 11 neurosurgeons between 2004 and 2007. The pre-operative medical conditions, methods of biopsy and postoperative complications were analyzed.

RESULT

The overall diagnostic yield was 90.64%. Complications were observed in 7.36% of the cases, with symptomatic hemorrhages occurring in 4.35% of the cases, and the overall mortality rate in this study population was 1.34%. Patients with liver cirrhosis were at a higher risk of hemorrhage. Other clinical, radiological, or histological variables were not associated with an increased risk of complications.

CONCLUSION

Stereotactic brain biopsy is a safe and reliable way to obtain a histological diagnosis. Based on our recent clinical experiences, the data suggests that more attention should be paid to liver cirrhotic patients, since the chance on hemorrhage is significantly larger.