Accuracy of frameless and frame-based image-guided stereotactic brain biopsy in the diagnosis of glioma: comparison of biopsy and open resection specimen

OBJECTIVES: Tissue heterogeneity and rapid tumor progression may decrease the accuracy a prognostic value of stereotactic brain biopsy in the diagnosis of gliomas. Correct tumor grading is therefore dependent on the accuracy of biopsy needle placement. There has been a dramatic increase in the utilization of frameless image-guided stereotactic brain biopsy; however, its accuracy in the diagnosis of glioma remains unstudied. METHODS: The diagnoses of 21 astrocytic brain tumors were derived using image-guided stereotactic biopsy (12 frame-based, nine frameless) and followed by open resection of the lesion 1.5 (0.5-4) months later. The histologic diagnoses yielded by the biopsy were compared with subsequent histologic diagnosis from open tumor resection. RESULTS: Histology of 21 stereotactic biopsies accurately represented the greater lesion at open resection a median of 45 days later in 16 (76%) cases and correctly guided therapy in 19 (91%) cases. Biopsy accuracy of frameless versus frame-based stereotaxis was similar (89 versus 66%, p=0.21). In three (14%) cases, biopsy specimens were adequate to diagnose glioma; however, histology was insufficient for definitive tumor grading. Anaplastic oligodendroglioma (ODG) was under-graded as low-grade ODG in one (5%) case. Biopsy of new onset glioblastoma multiforme (GBM) yielded necrosis/gliosis and was termed non-diagnostic in one patient. Tumors <50 cm(3) were 8-fold less likely to accurately represent the grade of the entire lesion at resection compared with lesions <50 cm(3) (OR, 8.8; 95% CI, 0.9-100, p=0.05). DISCUSSION: Both frameless and frame-based MRI-guided stereotactic brain biopsy are safe and accurately represent the larger glioma mass sufficiently to guide subsequent therapy. Large tumor volume had a higher incidence of non-concordance. Increasing the number of specimens taken through the long dimension of large tumors may improve diagnostic accuracy.     

Comparative analysis of diagnostic accuracy of different brain biopsy procedures

BACKGROUND: Image-guided procedures such as computed tomography (CT) guided, neuronavigator-guided and ultrasound-guided methods can assist neurosurgeons in localizing the intraparenchymal lesion of the brain. However, despite improvements in the imaging techniques, an accurate diagnosis of intrinsic lesion requires tissue sampling and histological verification. AIMS: The present study was carried out to examine the reliability of the diagnoses made on tumor sample obtained via different stereotactic and ultrasound-guided brain biopsy procedures. MATERIALS AND METHODS: A retrospective analysis was conducted of all brain biopsies (frame-based and frameless stereotactic and ultrasound-guided) performed in a single tertiary care neurosciences center between 1995 and 2005. The overall diagnostic accuracy achieved on histopathology and correlation with type of biopsy technique was evaluated. RESULTS: A total of 130 cases were included, which consisted of 82 males and 48 females. Age ranged from 4 to 75 years (mean age 39.5 years). Twenty per cent (27 patients) were in the pediatric age group, while 12% (16 patients) were >or= 60-years of age. A definitive histological diagnosis was established in 109 cases (diagnostic yield 80.2%), which encompassed 101 neoplastic and eight nonneoplastic lesions. Frame-based, frameless stereotactic and ultrasound-guided biopsies were done in 95, 15 and 20 patients respectively. Although the numbers of cases were small there was trend for better yield with frameless image-guided stereotactic biopsy and maximum diagnostic yield was obtained i.e, 87% (13/15) in comparison to conventional frame-based CT-guided stereotactic biopsy and ultrasound-guided biopsy. CONCLUSIONS: Overall, a trend of higher diagnostic yield was seen in cases with frameless image-guided stereotactic biopsy. Thus, this small series confirms that frameless neuronavigator-guided stereotactic procedures represent the lesion sufficiently in order to make histopathologic diagnosis.     

Prospective study on the efficacy of low-field intraoperative magnetic resonance imaging in neurosurgical operations

Background and purposeThe application of intraoperative magnetic resonance imaging (iMRI) is related to a series of challenges of both a technical and an organizational nature. We present our experience in the application of low-field iMRI in everyday neurosurgical practice.Material and methodsA group of 58 patients operated on using low-field iMRI was subject to prospective controlled observation. The significance of differences in the range of preparation time, duration and direct operation results between the iMRI group and controls was analysed. The influence of epidemiological and demographic factors and technical aspects related to iMRI application on direct outcome of the surgery was assessed.ResultsTwenty-eight tumour resections using craniotomy, 17 transsphenoidal resections of pituitary adenomas and 13 stereotactic procedures were conducted in the group of 24 men and 34 women operated on using iMRI. The control group was not significantly different in terms of epidemiological and demographic factors. The preparation and operation times were significantly longer in the iMRI group (p < 0.001 and p = 0.002, respectively). Longer duration of the surgery was not related to an increased frequency of complications. A higher percentage of postoperative improvement in neurological status (31% vs. 14%, p = 0.045), lower complication percentage (10% vs. 28%, p = 0.03) and a similar time of hospitalization (13 ± 7 vs. 12 ± 4 days, p = 0.33) were noted in the iMRI group.ConclusionsThe application of low-field iMRI prolongs the duration of neurosurgical procedures but does not negatively influence their safety. It is associated with above-average functional results and a lower percentage of total complications.     

Biopsia cerebral estereotáctica sin marco: capacidad diagnóstica y complicaciones

ObjectiveThe aim of this study was to evaluate the variables that could modify the diagnostic yield of frameless stereotactic biopsy, as well as its complications.Materials and methodThis was a retrospective study of frameless stereotactic biopsies carried out between July 2008 and December 2011 at Donostia University Hospital. The variables studied were size, distance to the cortex, contrast uptake and location.ResultsA total of 70 patients were included (75 biopsies); 39 males and 31 females with an age range between 39 and 83 years.The total diagnostic yield in our series was 97.1%. For lesions >19 mm, the technique offered a sensitivity of 95.2% (95% CI: 86.9-98.4) and specificity of 57.1% (95% CI: 25.0-84.2). The yield was lower for lesions within 17 mm of the cortex: sensitivity of 74.6% (95% CI: 62.1-84.7) and specificity of 71.4% (95% CI: 29.0-96.3).Seven (10%) patients developed complications after the first biopsy and none after the second.ConclusionsThe diagnostic yield was lower for lesions less than 2 cm in size and located superficially.In this series we did not observe an increased rate of complications after a second biopsy.     

Intraindividual comparison of histopathological diagnosis obtained by stereotactic serial biopsy to open surgical resection specimen in patients with intracranial tumours

Background

There are concerns in the literature about the accuracy of histopathological diagnosis obtained by stereotactic biopsy in patients with brain tumours. The aim of this study was to analyse intraindividually the histopathological accuracy of stereotactic biopsies of intracerebral lesions in comparison to open surgical resection.

Materials and methods

Between 2007 and 2011 a total of 635 patients underwent stereotactic serial biopsy in our department. Among these patients we identified 51 patients, who underwent magnetic resonance (MR) based stereotactic biopsy and subsequent open resection within 30 days. Mortality and morbidity data as well as final histopathological diagnoses of both procedures were compared with regard to tumour grade and tumour cell type. Patients with discrepancies between the histological diagnosis obtained by biopsy and open resection were classified into three subgroups (same cell type but different grading; same grading but different cell type and different grading as well as different cell type).

Results

The mean number of tissue samples taken by stereotactic serial biopsy from each patient was 12 (range 7–21). Minor morbidity was 6% and major morbidity was 14% after open surgery compared to no morbidity after stereotactic biopsy. Mortality was 2% after stereotactic biopsy (one patient died after stereotactic biopsy as a result of a fatal bleeding) compared to 0% in the resection group. Silent bleeding rate without any clinical symptoms was 8% in the biopsy group. A complete correlation of histopathological findings between the biopsy group and the resection group was achieved in 76% and was increased to 90% by analyzing clinical and neuroradiological information. In patients with recurrence the correlation was higher (94%) than for patients with primary brain lesions (67%). The discrepancies between the open resection group and biopsy group were analysed.

Conclusion

Stereotactic MR guided serial biopsy is a minimal invasive procedure with low morbidity and high diagnostic accuracy for diagnosis and grading of brain tumours. Diagnostic accuracy of stereotactic biopsy can be enhanced further by careful interpretation of neuroradiological and clinical information.     

A modified method to perform the frameless biopsy.

Neuronavigation is increasingly being used to assist in stereotactic neurosurgery due to its frameless property. In this study, we developed and assessed a modified method of performing stereotactic brain biopsies by combining the use of the Fisher stereotactic biopsy instrument, that was fixed on universal quick-lock holder, under infrared guidance of the BrainLab VectorVision Neuronavigation system. Eighteen patients received a frameless stereotactic procedure in this study, including 5 cases of brain biopsy, 2 cases of abscess aspiration, 10 cases of hematoma aspiration and one case of Ommaya reservoir implantation. All cases were on target and successful. In this paper, we present our technique, discuss the advantage and disadvantages of the method and review the literature.     

Frameless stereotactic brain biopsy procedures using the Stealth Station: indications, accuracy and results

This study presents the results of 57 stereotactic brain biopsies using a frameless neuronavigation system, the Stealth Station. The supratentorial lesions had a mean diameter of 33 mm and a mean distance of 32 mm from the entry point at brain surface. In all cases the stereotactic procedure was planned in the preoperative 3-D magnetic resonance data set. In seven cases additional data for identification of eloquent brain areas was integrated from magnetoencephalography or functional magnetic resonance imaging. During surgery the samples were sent to neuropathological examination and the operation completed after the confirmation of pathological tissue. Using this method, in 56 cases a pathological tissue was obtained and a diagnostic yield of 98% was achieved. In two cases (3.5%) a new neurological deficit remained (hemiparesis and visual field deficit). The mean operation time was 92 minutes including examination of frozen sections. The results of our series demonstrate, that frameless stereotactic systems can also be reliably applied for biopsy of supratentorial lesions larger than 15 mm. Frameless stereotaxy in combination with intraoperative pathological confirmation is a safe and reliable method for stereotactic brain biopsy with a diagnostic yield comparable to frame-based stereotaxy.     

Frameless stereotactic aspiration and thrombolysis of deep intracerebral hemorrhage is associated with reduction of hemorrhage volume and neurological improvement

Introduction: This ia a phase-2 safety trial to demonstrate the ability of frameless stereotactic aspiration and thrombolysis of ICH to safely remove blood. Methods: Patients with ICH in the deep basal ganglia and internal capsule of >5 cc volume were consented to undergo computed tomographic imaging for frameless stereotactic guidance registration. Using the frameless stereotactic (CT) guidance, a 4-mm diameter catheter was inserted into the body of the hematoma using a frontal burr hole approach. The catheter was aspirated and then flushed with saline and aspirated to remove unclotted blood. After a confirmatory CT scan to localize the catheter, 1 mg of recombinant tissue plasminogen activator (t-PA) was infused into the clot, permitted to bathe the clot for 30 minutes, and then drained into a closed circuit collection system. t-PA was infused every 8 hours for 48 hours. A follow up CT scan was obtained at 48 hours. Results: 28 patients with ICH (mean age 67.1) were admitted and underwent the procedure. Mean initial ICH volume was 54.6 cc ± 37.8. Mean time from onset to aspiration was 44 hours (range 7–180). Mean initial NIH Stroke scale (NIHSS) score was 24 (range 15–33). Compared with initial CT scan, there was a mean reduction of ICH volume by 77 ± 13% on final CT scan (p<0.0002). Compared with initial NIHSS, the discharge mean NIHSS (16 ± 6) was significantly improved (p<0.001). There were no infectious, hemodynamic or neurologic complications. There were no episodes of symptomatic hemorrhagic enlargement and one case of asymptomatic bleeding along the catheter tract. Conclusion: Frameless stereotactic aspiration and thrombolysis (FAST) of deep spontaneous intracerebral hemorrhage is a safe therapy that is associated with reduction in ICH volume, early improvement in NIHSS and potentially could be used to improve outcome.     

MRI-guided frame-based stereotactic brainstem biopsy procedure: A single-center experience

Introduction and objectivesThis study aims at presenting our experience of the MRI-guided frame-based stereotactic brainstem biopsy method, and evaluating the outcomes of the procedure.Patients and methodsThe current study involved 18 cases that underwent MRI-guided frame-based stereotactic biopsy for brainstem lesions between 2011 and 2018 in our clinic. The relevant data regarding the technique of the biopsy procedure, morbidity, histopathological diagnosis it yields and diagnostic accuracy was retrospectively analyzed.ResultsStereotactic biopsy procedure was performed on 18 patients, including 16 adults and two children. MRI was used as guidance for the biopsy procedure in all patients. The adult patients had the biopsy under local anesthesia; as for the pediatric patients local anesthesia plus sedation was used. All patients received diagnosis based on the histopathological examination of their biopsy samples. No equivocal or negative results, and no major morbidity or mortality was seen in the patients after the procedure.ConclusionsMRI-guided frame-based stereotactic biopsy can be considered as a safe and efficient diagnostic method for brainstem lesions when its diagnostic yield and its morbidity and/or mortality rates are evaluated. Choosing the best trajectory for each lesion, using MRI as guidance for targeting, taking a limited number of biopsy samples are valuable criteria for the decreased morbidity rates in stereotactic brainstem biopsy procedures.     

颅内特殊部位病变的立体定向活检术

目的 探讨颅内特殊部位病变立体定向活检的手术技巧及影响因素.方法 总结1994年12月～2005年12月间对颅内特殊部位病变行MR导向立体定向活检的106例病例.患者年龄6～76岁,平均42.5岁,其中男62例,女44例,病灶位于鞍区13例,基底节区35例,松果体区51例,脑干7例.使用1.0T MR机定位和Leksell-G型定向仪,ASA-602立体定向手术计划系统行定位影像三维重建并选择最佳靶点、入颅点和活检轨迹.所有靶点均使用Sedan活检针活检,活检组织标本行术中快速冰冻病检,术后行常规病理检查,必要时行免疫组化检查.结果 本组106例,获得明确病理诊断103例,其中生殖细胞瘤37例,松果体母细胞瘤5例,淋巴瘤11例,转移瘤14例,感染性病灶7例,胶质瘤26例,脑变性疾病3例;阴性(轻度胶质增生)3例.病理诊断阳性率97.17%.活检后少量出血2例,全组病例无死亡.结论 立体定向活检术是一种安全、定位精确、高诊断率的脑部疑难病变定性诊断方法,对颅内特殊部位病变的病理学诊断具有重要价值.     

术中磁共振实时影像导航下穿刺活检术的临床初步应用

目的 探讨术中磁共振(iMRI)影像导航应用于穿刺活检术的临床初步经验、优势与不足.方法 在0.15T PoleStar N-20 iMRI实时影像引导下,对6例颅内占位性质不明患者进行穿刺活检术.结果 6例均获得组织病理学诊断,活检阳性率为100%;1例颅内多发占位患者术后并发左基底节活检区域局限性血肿.结论 iMRI影像导航能及时纠正术中脑移位,即只有当iMRI确定穿刺针已位于病灶内才进行活检,从而有利于提高活检阳性率,减少术后并发症.     

CT、MRI引导立体定向脑活检术的临床研究

目的评价CT或MRI引导立体定向活检术在确定脑深部病变的病理组织学诊断及选择适宜的治疗方法中的作用.方法采用计算机体层摄影(CT)或磁共振成像(MRI)引导立体定向技术对420例脑深部或脑主要功能区病灶进行了活检手术.其中男252例,女168例,年龄4.5～71岁,平均40.3岁.病变位于脑深部104例,鞍区82例,基底节区78例,三脑室后部50例,多发病灶48例,脑室内23例,小脑半球19例,脑干内14例,斜坡2例.CT引导手术386例,MRI引导手术34例.结果共有405例作出了病理诊断,活检总阳性率为96.43%,其中肿瘤359例(85.48%),炎性病变33例(7.86%),其他病变13例(3.10%).未作出病理诊断者15例(3.57%).共发生手术并发症7例(1.67%)出血5例(1.2%),癫痫1例,意识障碍1例.结论 CT或MRI引导的立体定向脑深部病变活检术是一种明确颅内占位病变的组织学诊断的可靠方法,并能为临床治疗方法的选择提供依据.     

颅内多发病灶的立体定向活检术后病理学结果与MRS结果的比较分析

目的探讨立体定向活检术及磁共振波谱成像（MRS）在颅内多发病灶定性诊断中的临床价值。方法回顾性分析37例经MRI、MRS和立体定向活检术后病理学检查确诊的颅内多发病灶患者的临床资料,其中行有框架定向活检术22例,无框架神经导航定向活检术15例。结果 37例均获得明确病理学诊断,其中低级别胶质瘤19例,高级别胶质瘤8例,淋巴瘤3例,多发脱髓鞘3例,炎性病灶2例,转移癌2例。术后出现癫痫发作1例,活检靶点少量出血1例。病理学诊断与MRS诊断符合率为83.8%（31/37）,误诊率为16.2%（6/37）。结论 MRS在颅内多发病灶的诊断中具有较高的准确性,但仍有一定的误诊率;立体定向活检术微创、安全,在颅内多发病灶的诊断中具有决定性的意义;MRS的代谢变化在活检术靶点选择上具有一定的指导价值。     

Peripheral compressing artifacts in brain tissue from stereotactic biopsy with sidecutting biopsy needle: a pitfall for adequate glioma grading

Aims: The stereotactic brain biopsy is an essential diagnostic procedure in modern neurologic patient management. A side-cutting biopsy needle is one of the most widely used needle types. Recently we found a characteristic tissue artifact named "peripheral compressing artifact" in the brain tissues biopsied using a side-cutting needle of Leksell's system. We investigate prevalence, possible cause and its clinical implication of this type of artifact. Materials and methods: We examined the biopsies from 80 patients (44 cases of gliomas, 13 lymphomas, 7 germ cell tumors, 2 other tumors, 1 metastatic carcinoma, 4 non-tumorous conditions such as demyelinating disease and 8 non-diagnostic) in the stereotactic biopsy group with a suspected brain tumor, who underwent a stereotactic brain biopsy using side-cutting needle of Leksell's system. We also evaluated 16 cases of open brain biopsies without Leksell's system as a control group. Results: The artifact is a semi-circular or band-like tissue compression in the periphery of the biopsied tissue. This artifact was found in 30 (37.5%) out of 80 cases and 57 (11.9%) out of 477 biopsied pieces. It might be produced during rotating of the inner cannula of the biopsy needle. Histologically, it might be misinterpreted as "hypercellular", "spindle", "well circumscribed", or rarely as "pseudopalisading" especially in glioma. Conclusions: Awareness of this artifact would help making the appropriate pathological diagnosis for glioma.     

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 ¹H Magnetic Resonance Spectroscopy (¹H-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.     

805例立体定向脑活检报告

目的　探讨立体定向脑活检方法的可靠性和安全性 ,研究手术方法及技术要点。方法　回顾性分析80 5例立体定向手术对脑深部病灶活检病理学检查。其中用CT引导活检 6 0 5例 ,MR引导活检 2 0 0例 ;幕上脑深部活检 6 4 5例 ,幕下病灶活检 16 0例 ;单道入路活检取材 5 30例 ,多道入路活检取材 2 0 5例 ,多发病灶活检取材 70例。结果　 710例 (88 2 0 % )获取各类脑肿瘤的病理学诊断 ,5 0例 (6 2 1% )为炎性病理 ,2 5例 (3 11% )为寄生虫或囊肿类病理 ,其余 2 0例 (2 4 8% )所取得的病理组织未能提供正确的病理定性诊断。病理阳性诊断率为 97 5 2 % ,肿瘤发现率为 88 2 0 % ,死亡 3例 ,死亡率 0 37% ,并发症发生 19例 (2 36 % )。结论　现代立体定向脑深部病灶活检技术安全、可靠。     

立体定向活检术在颅内无强化效应病变中的诊断价值

目的 探讨立体定向活检术在颅内无强化效应病变中的定性诊断价值.方法 对47例在MRI增强扫描中未见明显强化的颅内病变行立体定向活检,其中MRI引导有框架立体定向活检38例,无框架神经导航定向活检9例.结果 获得明确病理诊断42例,未获得阳性病理结果5例,活检病理诊断阳性率89.4％.对颅内非肿瘤性病变,MRI诊断与病理诊断相符合9例;对肿瘤性病变,MRI诊断与病理诊断相符合14例;MRI诊断与病理诊断的符合率为48.9％.活检术后穿刺道少量出血1例,无颅内感染和死亡病例.结论 对颅内无强化效应的病变,立体定向活检是获得定性诊断安全、可靠的方法.     

氢质子磁共振波谱和术中磁共振导航在颅内病变无框架活检的初步应用

目的 探讨氢质子磁共振波谱(proton magnetic resonance spectroscopy,1H-MRS)联合术中磁共振(intraoperative magnetic resonance imaging,iMRI)导航在颅内病变穿刺活检的应用.方法 使用兼具有1H-MRS功能的1.5 T术中磁共振系统,并配有导航计算机成像系统.26例颅内病变患者,先使用1H-MRS分析病灶组织生化及代谢情况,然后在iMRI导航引导下根据病变不同部位代谢情况对病变相应区域进行穿刺活检.结果 26例患者穿刺成功,25例病变组织获得组织病理学诊断.所有病例术中及术后均未出现明显并发症如严重出血、新发神经功能障碍等.结论 1H-MRS分析能提供病变的代谢信息,并帮助确定最佳活检取材点,iMRI导航能精确定位,并在术中明确取材位置和排除出血等并发症,1H-MRS联合iMRI导航在颅内病变活检是一种精准、有效、安全的技术.     

Molecular genetic analysis as a tool for evaluating stereotactic biopsies of glioma specimens

Over the last years, distinct genetic lesions have been associated with individual tumor entities. Stereotactic biopsy has become an essential diagnostic tool in surgical neuro-oncology. In order to evaluate the potential of molecular analyses in stereotactic biopsies, we examined a series of 156 human brain tumors from patients undergoing stereotactic biopsy for molecular alterations typically seen in astrocytic gliomas and compared those results with a control group of 268 astrocytic tumors obtained at open surgery. Stereotactic biopsies of astrocytomas with borderline histopathological features between the WHO grades II and III showed a higher rate of allelic losses on chromosome 10 than those of the WHO grade II from open surgery (p = 0.011). Stereotactic biopsies of astrocytomas with borderline histopathological features between the WHO grades III and IV showed a higher rate of allelic losses on chromosome 10 than those of the WHO grade III from open surgery (p = 0.013). This indicates that stereotactic biopsies with features intermediate between grades are likely to correspond to the higher malignancy grade. Our data demonstrate that molecular genetic approaches can be successfully applied to stereotactic glioma biopsies. The difference in the distribution of malignancy associated genetic alterations between a stereotactic and openly resected group of gliomas indicates that histopathology may underestimate the malignant potential in some stereotactic specimens. We propose to further evaluate the molecular analysis of stereotactic glioma biopsies as a useful adjunct to standard histopathological procedures.     

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

Objective

Comparative evaluation of diagnostic efficacy of stereotactic brain biopsy performed with and without additional use of spectroscopic imaging (¹H-MRS) for target selection was done.

Methods

From 2002 to 2006, 30 patients with parenchymal brain lesions underwent ¹H-MRS-supported frame-based stereotactic biopsy, whereas in 39 others MRI-guided technique was used. Comparison of diagnostic yield of the procedure in these two groups was performed. Additionally, the diagnostic accuracy was evaluated in 37 lesions, which were surgically resected within 1 month thereafter.

Results

Stereotactic biopsy permitted establishment of a definitive histopathological diagnosis in 57 cases and diagnosis of low-grade glioma without specific tumor typing in 8 cases. In 4 cases tissue sampling was non-diagnostic. In 5 out of 8 cases with incomplete diagnosis and in all non-diagnostic cases target selection was performed without the use of ¹H-MRS (P = 0.2073). The diagnostic yields of ¹H-MRS-supported and MRI-guided procedures were 100% and 90%, respectively (P = 0.1268). Comparison of the histopathological diagnoses after stereotactic biopsy and surgical resection revealed complete diagnostic agreement in 13 cases, minor disagreement in 14 cases, and major disagreement in 10 cases. Among these last 10 cases, initial undergrading of non-enhancing WHO grade III gliomas was the most common (7 cases). The diagnostic accuracy of ¹H-MRS-supported and MRI-guided procedures was 67% and 79%, respectively (P = 0.4756).

Conclusion

While in the present study the diagnostic yield of ¹H-MRS-supported frame-based stereotactic brain biopsy was 100%, its statistically significant diagnostic advantages over MRI-guided technique were not proved. Optimal selection of the spectroscopic target for tissue sampling remains unclear.