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.     

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.     

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

ObjectiveProton 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.MethodsDuring 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.Results65 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.ConclusionThe 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.     

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.     

Complications in 622 cases of frame-based stereotactic biopsy, a decreasing procedure

BACKGROUND: Frame-based stereotactic brain biopsy has played an important role in the management of patients with suspected neoplastic intracranial lesions over the last three decades. We reviewed the surgical experience of one surgeon to determine the nature and frequency of complications associated with this procedure. METHODS: Records were reviewed for 858 patients undergoing frame-based stereotactic procedures from January 1986 to May 2006. Data on each case were prospectively collected by the senior author. Procedures for Ommaya reservoir placement, brachytherapy, stereotactic craniotomy flap localization, shunt placement, or treatment of previously-diagnosed intracranial cystic lesions were excluded, leaving 614 patients in whom a total of 622 procedures were performed for purely diagnostic purposes. Complication rates and their association with clinical variables were sought. RESULTS: Morbidity and mortality rates were 6.9% (43/622) and 1.3% (8/622), respectively. The risk of symptomatic hemorrhage (intracerebral hemorrhage [ICH], subarachnoid hemorrhage [SAH], intraventricular hemorrhage [IVH]) was 4.8%. The risks of transient or permanent neurological deficits were 2.9% (18/622) and 1.5% (9/622), respectively. Biopsy of deep-seated lesions was associated with increased overall complication rate, while biopsy of Glioblastoma Multiforme (GBM) was associated with perioperative mortality. CONCLUSIONS: Overall, complication rates were comparable with those in previous reports. The subgroup of patients with deep-seated lesions or a histologic diagnosis of GBM may possess an elevated risk of overall complications or mortality, respectively, compared to other patients undergoing frame-based stereotactic brain biopsy.     

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.     

Rosa机器人辅助立体定向颅内活检术的临床应用

目的 探讨Rosa机器人辅助下立体定向颅内活检术的临床应用效果。方法 回顾性分析2018年10月至2020年8月在Rosa机器人辅助下进行颅内占位立体定向活检术的33例病人的临床资料。结果 术中没有发生导航故障,所有程序都如期完成。33例进行76个靶点穿刺活检术,术后未发现颅内出血,术后无癫痫发作。33例活检阳性率为100%,其中胶质瘤21例,弥漫大B细胞淋巴瘤5例,血管畸形2例,转移性腺瘤1例,生殖细胞肿瘤2例,间变性脑膜瘤1例,炎性脱髓鞘1例。21例胶质瘤中,检测出IDH-1突变6例（28.6%）,MGMT启动子甲基化16例（76.2%）。1例间变性少突胶质细胞瘤检测出1p/19q杂合性缺失。结论 Rosa机器人辅助立体定向无框架活检术是一种相对安全,可行的操作,可用于颅内病变的组织学和分子诊断。     

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.     

Influence of the type of surgery on the histologic diagnosis in patients with anaplastic gliomas.

Stereotactic biopsy of CNS tumors provides a small amount of tissue for pathologic diagnosis. This potentially leads to inaccurate grading of gliomas because of their histologic heterogeneity. We compared histologic diagnoses in a consecutive series of 329 patients with newly diagnosed anaplastic gliomas whose diagnoses were established by either stereotactic biopsy or open resection. Of 262 patients undergoing resection, 214 (82%) had glioblastomas and 48 (18%) had anaplastic astrocytomas (AAs). Of 67 patients undergoing stereotactic biopsy, 33 (49%) had glioblastomas and 34 (51%) had AAs. This difference suggests that some AAs diagnosed by stereotactic biopsy are actually glioblastomas and has important implications for the design and interpretation of clinical trials.     

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.     

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.     

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.     

Subcutaneous tumoral seeding from a glioblastoma following stereotactic biopsy: case report and review of the literature

Extracranial metastases from glioblastoma are uncommon, likely because short patient survival time prevent them to occur. Most of the few previously reported cases occurred after invasive surgical procedures. We describe a case of glioblastoma with concomitant seeding along the stereotactic biopsy trajectory and subcutaneous metastasis. A 60-year-old woman presented with severe headache. Neuroradiological work-up (including cranial computed tomographic scan and magnetic resonance imaging) showed a heterogeneous hyperdensity, suggestive of malignant glioma, in the left parietal region. A computed tomographic-guided stereotactic biopsy was performed and microscopic examination attested a diagnosis of glioblastoma. Radiotherapy and chemotherapy were administered. Eight months later, the patient presented with a subcutaneous tumor in the left occipital region. A cranial computed tomographic scan revealed a large enhancement of the initial tumor, intracranial tumor seeding along the stereotactic biopsy trajectory, and a subcutaneous tumor. Partial resection of the subcutaneous lesion was performed, and histological examination identified an extracranial metastasis from the glioblastoma. Although uncommon, this observation points to the risk of tumor seeding following stereotactic biopsy, and to the close connection between this intracranial seeding and subcutaneous metastasis.     

Technique of stereotactic biopsy in a 5-month-old child

We describe a technique of stereotactic frame-based biopsy in young children who have open fontanels and a deformable skull. A 5-month-old girl with a growing lesion in the right thalamus and basal ganglia underwent stereotactic biopsy, which disclosed an anaplastic astrocytoma. To avoid insertion of the four stereotactic frame fixation pins through the infant's skin and into bone, the pins were advanced into the hollowed end of rubber tops obtained from Vacutainer blood sampling tubes. The pressure applied to the skin was diffused through the rubber onto a wide skin surface, obviating skin puncture or bone deformation. This technique provided firm head fixation, and target accuracy was confirmed on post-operative imaging. This technique is safe and should permit use of conventional stereotactic techniques in young infants.     

Frame-less and frame-based stereotaxy? How to choose the appropriate procedure

In recent years, additional tools for image guided surgery have been developed. Devices are now available for frameless punction and biopsy of intracerebral lesions and the indications for frameless and frame-based stereotaxy are increasingly overlapping. The objective of our paper was to analyse the most important factors that influence the decision on when to use frameless and when frame-based stereotaxy. Criteria such as application accuracy, image information and ergonomics were investigated for different lesions. Frameless and frame-based stereotaxy are complementary systems with different indications. They are different in terms of image information and ergonomics. Image guided surgery is the standard for continuous 3-dimensional topographical orientation. With high quality images (1 mm slice thickness) and bone marker registration, frameless stereotaxy may achieve an application accuracy comparable to frame-based systems. However, when using adhaesively mounted skin fiducials for patient registration, frameless stereotaxy is less accurate than framebased systems. Therefore, the size of the lesion should exceed 10 mm for punction and biopsy with a frameless system. Frame-based stereotaxy remains the gold standard for accurate targeting of lesions < 10 mm and for functional procedures.     

PET imaging in the surgical management of pediatric brain tumors

Objective The present article illustrates whether positron-emission tomography (PET) imaging may improve the surgical management of pediatric brain tumors (PBT) at different steps. Materials and methods Among 400 consecutive PBT treated between 1995 and 2005 at Erasme Hospital, Brussels, Belgium, we have studied with ¹⁸ F-2-fluoro-2-deoxy-D-glucose (FDG)–PET and/or L-(methyl-¹¹C)methionine (MET)–PET and integrated PET images in the diagnostic workup of 126 selected cases. The selection criteria were mainly based on the lesion appearance on magnetic resonance (MR) sequences. Cases were selected when MR imaging showed limitations for (1) assessing the evolving nature of an incidental lesion (n = 54), (2) selecting targets for contributive and accurate biopsy (n = 32), and (3) delineating tumor tissue for maximal resection (n = 40). Whenever needed, PET images were integrated in the planning of image-guided surgical procedures (frame-based stereotactic biopsies (SB), frameless navigation-based resections, or leksell gamma knife radiosurgery). Results Like in adults, PET imaging really helped the surgical management of the 126 children explored, which represented about 30% of all PBT, especially when the newly diagnosed brain lesion was (1) an incidental finding so that the choice between surgery and conservative MR follow-up was debated, and (2) so infiltrative or ill-defined on MR that the choice between biopsy and resection was hardly discussed. Integrating PET into the diagnostic workup of these two selected groups helped to (1) take a more appropriate decision in incidental lesions by detecting tumor/evolving tissue; (2) better understand complex cases by differentiating indolent and active components of the lesion; (3) improve target selection and diagnostic yield of stereotactic biopsies in gliomas; (4) illustrate the intratumoral histological heterogeneity in gliomas; (5) provide additional prognostic information; (6) reduce the number of trajectories in biopsies performed in eloquent areas such as the brainstem or the pineal region; (7) better delineate ill-defined PBT infiltrative along functional cortex than magnetic resonance imaging (MRI); (8) increase significantly, compared to using MRI alone, the number of total tumor resection and the amount of tumor tissue removed in PBT for which a total resection is a key-factor of survival; (9) target the resection on more active areas; (10) improve detection of tumor residues in the operative cavity at the early postoperative stage; (11) facilitate the decision of early second-look surgery for optimizing the radical resection; (12) improve the accuracy of the radiosurgical dosimetry planning. Conclusions PET imaging may improve the surgical management of PBT at the diagnostic, surgical, and post-operative steps. Integration of PET in the clinical workup of PBT inaugurates a new approach in which functional data can influence the therapeutic decision process. Although metabolic information from PET are valid and relevant for the clinical purposes, further studies are needed to assess whether PET-guidance may decrease surgical morbidity and increase children survival.     

组织定向活检诊断为胶质瘤与手术病理符合率的比较研究

目的探讨组织定向活检技术在诊断胶质瘤中的病理定性诊断价值。方法回顾性分析住院胶质瘤病例51例,比较活检与手术的病理情况。活检部位为额叶23例,颞叶15例,顶叶7例,枕叶3例,多发病例3例。肿瘤位于右侧半球27例,左侧24例。其中临床考虑胶质瘤复发者7例。结果手术病理同样确定为胶质瘤者39例,临床符合率为76.4%;淋巴瘤1例,炎性肉芽肿2例,脑感染性疾病2例,放射性脑坏死4例,脑梗死3例。手术中确诊为胶质瘤,但是活检确诊为低级别胶质瘤,而手术病理确诊为高级别胶质瘤者13例,占33%。结论对于活检病理确诊为胶质瘤的可靠性需要进行新的评估。     

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.     

Accuracy and diagnostic yield of stereotactic biopsy in the diagnosis of brain masses: Comparison of results of biopsy and resected surgical specimens

The aim of this retrospective study was to investigate the diagnostic yield and accuracy of stereotactic biopsy in patients harboring brain mass. Stereotactic biopsy was performed in 130 patients between 1995 and 2000 in an educational and research hospital in Turkey. The results of histological analysis were compared to the resected specimens in 23 patients. The lesions were lobar in 62% of cases and deep‐seated in 38% of cases. During the biopsy procedures, the pathologist was in the operating theatre and a very small fragment was used for cytological examination. No frozen section was used in any of the cases. Samples were diagnostic in 122 cases. The overall diagnostic yield of the procedure was 94%. A definitive histological diagnosis was not made in eight patients. The histological diagnoses of the two procedures were identical (complete agreement) in 16 cases. In three cases, the histological diagnoses between the two procedures were slightly different without impact on patient care (minor disagreement). The diagnosis of the stereotactic biopsy was completely changed after craniotomy in four cases (major disagreement). The accuracy of the histological diagnosis was 83%. There was only one major complication, which involved intracerebral hemorrhage. Despite the limited number of patients who underwent resection, our data suggest that stereotactic biopsy of brain masses is a safe and accurate technique that can obtain adequate tissue for histological diagnosis, thus providing the best avaible treatment for patients. Cytological evaluation of the streotactic biopsy also is a highly effective tool for obtaining sufficient material during the procedure in many cases.     

影响立体定向活检的相关因素分析

目的：探讨影响立体定向活检的相关因素。方法：回顾性总结1994年12月至2000年6月间我科收治并行MRI导向立体定向活检的156例病例。患者年龄6－72岁,平均45．5岁,其中男89例,女67例;病灶位于鞍区5例,基底节区33例,松果松区46例,中脑2例,侧脑室壁2例,三脑室底部2例,额叶深部28例,颞叶9例,顶枕叶6例,多发性病灶23例。手术采用Leksell-G型定向仪和1．0TMR机（Siemens)。所有靶点活检均采用Sedan侧方开口活检针,标本立即行快速冰冻病检。结果：病理诊断阳性97．4％（152例）,其中低级别星型胶质瘤24例,高级别星型胶质瘤28例,室管膜瘤2例,转移瘤33例,感染性病灶29例,生殖细胞瘤31例,松果体母细胞瘤2例,垂体腺瘤1例,淋巴瘤2例,阴性4例。活检出血2例。术中癫痫发作1例,并发症发生率1．9％。全组病例无死亡。结论：影像导向立体定向活检术是一种安全、定位精确、高诊断率的微侵袭性脑深部疑难病变定位诊断方法。其影响因素包括影像定位技术、 靶点及活检通道选择、活检器械选择、并发症防治等。