Focal enhancement of cranial nerve V after radiosurgery with the Leksell gamma knife: experience in 15 patients with medically refractory trigeminal neuralgia.

BACKGROUND AND PURPOSE: Gamma knife radiosurgery is an alternative for the treatment of medically refractory trigeminal neuralgia. Few reports of posttreatment MR imaging appearance of cranial nerve V exist. Our purpose was to define MR imaging characteristics in cranial nerve V after gamma knife radiosurgery. METHODS: We retrospectively reviewed MR images of 15 patients who underwent gamma knife radiosurgery for trigeminal neuralgia. Radiation doses were 35-45 Gy at the 50% isodose line. Thin-section T2-weighted images and contrast-enhanced and nonenhanced T1-weighted images were obtained the day of radiosurgery and within the next 5 mo. Images were scored for enhancement and hyperintensity on T2-weighted images. Time to follow-up imaging and radiation dose were recorded. RESULTS: Mean time to follow-up imaging was 61 +/- 29 d. Posttreatment T2-weighted images showed stable signal intensity in all cases, with radiosurgical target site enhancement in 10. All five patients whose images did not show treatment-related enhancement received radiation doses of 35 Gy. The data suggested a correlation between enhancement with radiation dose (P =.06). No correlation of enhancement with treatment response or time to follow-up existed (P >.05). CONCLUSION: The trigeminal nerve often enhances at the target site after radiosurgery. Lack of trigeminal nerve enhancement occurred only with lower doses (35 Gy at 50%). MR imaging may be useful to confirm the presence and location of the treatment site after gamma knife radiosurgery for trigeminal neuralgia.     

Gamma-knife radiosurgery for trigeminal neuralgia

Gamma knife was installed at the PD Hinduja National Hospital and Medical Research Centre, Mumbai, India, in January 1997. In the first year of gamma-knife radiosurgery to January 1998, we treated 110 patients, of whom six had medically refractory trigeminal neuralgia. Seven treatments were administered to this group of six patients (one had bilateral neuralgia). This report evaluates the effectiveness of radiosurgery treatment in these patients. The median age of the patients was 56 years and there were five males and one female. Following Leksell stereotactic frame fixation, a magnetic resonance imaging scan was done in all. The Leksell gamma plan was used for planning. A radiosurgery dose of 70-80 Gy was delivered to the trigeminal root entry zone, 2-4 mm anterior to the junction of the pons and trigeminal nerve with a single 4 mm collimator helmet. Complete pain relief was achieved in four patients. Two had partial relief. No patient developed any radiosurgery related morbidity during the follow-up period of 5-16 months. Radiosurgery seems to be an effective approach for medically or surgically refractory trigeminal neuralgia.     

3D-TOF磁共振血管成像诊断血管压迫性三叉神经痛的价值

目的　探讨增强薄层三维体积扫描时间飞跃法磁共振血管成像 ( 3D -TOFMRA)诊断血管压迫性三叉神经痛的价值。方法　回顾性分析 37例临床拟诊为血管压迫性三叉神经痛患者的常规颅脑MRI及增强薄层 3D -TOF磁共振血管成像资料。结果　增强薄层 3D -TOFMRA发现 37例中 2 4例共 2 7侧三叉神经存在血管压迫或接触 ,其中症状侧三叉神经有血管压迫或接触 2 4例 ,无症状侧三叉神经有血管压迫或接触 3例 ,本组病例统计学分析表明 ,三叉神经痛患者症状的出现与三叉神经存在血管压迫或接触有显著相关关系 (Ρ <0 .0 0 5 )。 13例为非血管压迫性三叉神经痛。压迫三叉神经的血管为小脑上动脉 (SCA) 14例 ,小脑前下动脉(AICA) 5例 ,起源不清的血管 3例 ,扭曲的椎动脉 1例 ,血管畸形 1例。结论　增强薄层 3D -TOFMRA可清楚显示三叉神经脑池段与毗邻血管的关系 ,明显优于常规颅脑MRI,是目前检测血管压迫性三叉神经痛最佳的影像学检查方法 ,对明确诊断和指导治疗三叉神经痛具有重大意义。     

立体定向放射外科治疗垂体泌乳素瘤

用直线加速器放射科(X刀)治疗16例垂体催乳素瘤。女性15例,男性1例,平均年龄27.5岁。曾用过溴隐亭治疗。采用MRI扫描确定腺癌的大小,CT扫描用于立体定向靶点定位、腺瘤的直径都限于4～10mm,与视交叉的间距为2～5mm。用5或7.5mm准直器,最大剂量20～25Gy。治疗后随访12个月、结果为:7例病人临床症状缓解,PRL恢复至20～25ng/ml;6例获改善,PRL降至40～100ng/ml;3例病人无变化,PRL>200ng/ml。MRI扫描发现11例病人瘤体消失或缩小,5例瘤体直径无变化。治疗前视力、视野正常者未发现治疗后的视觉功能损害,而3例已有视力视野损害的病人有2例治疗后获改善。结果表明,直线加速器放射外科是可供治疗垂体微腺瘤选择的有效而无创的手段。     

神经系统功能性疾病的伽玛刀治疗现状及展望

近20年来,随着CT、MR、SPECT、PET等影像技术的发展,颅内解剖学靶点如三叉神经、杏仁核、苍白球、VL核、扣带回及内囊前肢可获准确定位,立体定向伽玛刀放射治疗技术更趋于完善,神经系统功能性疾病的伽玛刀治疗再次成为临床研究热点。     

低场强MR在三叉神经痛病因诊断中的应用

目的 评估低场强MR在三叉神经痛病因诊断中的应用价值.资料与方法 对43例临床表现有三叉神经痛的患者行MRI检查,疼痛为间隙性或持续性.每例患者均行颅脑常规T_1WI、T_2WI及液体衰减反转恢复序列(FLAIR)扫描.阴性者加做三叉神经薄层扫描,其中有8例做了增强扫描.结果 阳性发现26例,阴性17例.26例中三叉神经脑池段周围血管压迫或接触14例,三叉神经鞘瘤2例,听神经瘤1例,桥前池胆脂瘤3例,蛛网膜囊肿2例,脑膜瘤2例,脑干脱髓鞘病变1例,脑干胶质瘤1例.结论 低场强MR对三叉神经痛原因的诊断有很高的价值,它不仅能发现三叉神经本身的病变,也能发现三叉神经周围组织病变对三叉神经的影响.     

Magnetic resonance imaging of idiopathic trigeminal neuralgia

Seventeen patients with idiopathic trigeminal neuralgia (ITN) and seven subjects of control group were evaluated with magnetic resonance imaging (MRI). Vascular contact at the proximal portion of the preganglionic segment (PGS) of the trigeminal nerve was observed in 100% of ITN on the affected side, 76% of ITN on the non-affected side, and 21% of control group. Deformity of the PGS was observed in 65% of ITN on the affected side, and in none of ITN on the non-affected side or control group. Non-surgical treatments were effective in all of the 6 patients without deformed PGS, but they failed to control trigeminal neuralgia in 4 of 11 patients with deformed PGS. This preliminary study suggests that MRI could be used for the clinical assessment of trigeminal neuralgia before treatment.     

三维时间飞跃对三叉神经痛的诊断价值

目的 探讨三叉神经痛神经患者的ＭＲ表现为其诊断价值。方法 应用三维时间飞跃（３Ｄ－ＴＯＦ）序列,结合ＳＥ及快速液体衰减反转恢复（ＦＬＡＩＲ）序列,回顾性分析了１０４例三叉神经痛患者ＭＲ表现及手术结果。结果 （１）１０４例三叉神经痛患者中ＭＲＩ诊断为血管压迫或接触的为７５例,术中证实有血管压迫或接触的为６９例;桥小脑角肿瘤共１４例,ＭＲＩ确诊１３例,另１例由手术确诊;血管性病变的为５例,均由微血管减     

无三叉神经痛者三叉神经与血管关系:3D FSPGR序列

目的 利用3D FSPGR序列研究无三叉神经痛受检者中三叉神经脑池段与邻近血管关系。资料与方法 回顾性分析50例无三叉神经痛患者增强轴位3D FSPGR图像，层厚1mm，分别观察双侧三叉神经周围是否存在血管影，同时测定三叉神经长轴与邻近血管的距离，根据神经周围血管有无及距离的远近分成无血管、远离、接近、接触、变形5种情况。结果 50例患者100侧三叉神经中，周围无血管的三叉神经占37％（右侧18例，左侧19例），其中12例双侧三叉神经周围皆无血管。在周围有血管的三叉神经中，接触占23％，接近占11％，远离占29％。所有研究对象中皆未发现血管引起的三叉神经变形。结论 3D FSPGR序列可用于三叉神经和邻近血管关系的研究。在无三叉神经痛者三叉神经与微血管接触率为23％，此结果可为三叉神经痛病因学的研究提供依据。     

Improved trigeminal and facial nerve tolerance following fractionated stereotactic radiotherapy for large acoustic neuromas

The purpose of this study was to demonstrate improved cranial nerve tolerance following fractionated stereotactic radiotherapy for large acoustic neuromas, defined as tumours with pons-petrous distance (A) > 1 cm and midporous transverse diameter (A + Y) > 2 cm. Of 28 patients with acoustic neuromas treated with fractionated stereotactic radiotherapy, 19 had large tumours at high risk for radiosurgery-induced cranial neuropathy. Six patients received 36 Gy in six, weekly, fractions and 13 patients received 30 Gy in six, weekly, fractions. 15 patients had evaluable trigeminal nerve function and 16 had evaluable facial nerve function. At a median follow-up of 4.5 years, tumour shrinkage was seen in 10 patients and tumour size was stable in nine. None of the patients developed any evidence of transient, or permanent, trigeminal or facial neuropathy at any time during their follow-up period. Fractionated stereotactic radiotherapy may offer a superior therapeutic ratio to single fraction stereotactic radiosurgery in the management of large acoustic neuromas, as evidenced by the absence of post-treatment trigeminal and facial neuropathy.     

Nerve atrophy in severe trigeminal neuralgia: noninvasive confirmation at MR imaging--initial experience

PURPOSE: To retrospectively evaluate the size of the trigeminal nerve on magnetic resonance (MR) images of patients with unilateral trigeminal neuralgia. MATERIALS AND METHODS: Institutional review board approval was obtained and informed consent was waived for this HIPAA-compliant study. The sizes of the trigeminal nerves in 31 patients (18 men and 13 women; mean age, 68 years; age range, 44-84 years) with clinically confirmed intractable unilateral trigeminal neuralgia were measured before treatment with gamma knife radiosurgery. Images were analyzed separately by two neuroradiologists who were blinded to the side of the face with symptoms. Coronal projection images were used to determine the diameter and cross-sectional area of the trigeminal nerves at 5 mm from the entry point of the nerve into the pons. Comparisons were made by using a paired t test. Interobserver variability was assessed by using the Pearson correlation coefficient. RESULTS: The mean diameter of the trigeminal nerve on the symptomatic side was significantly smaller than the mean diameter on the asymptomatic side in 30 of 31 patients (2.11 mm +/- 0.40 [standard deviation] and 2.62 mm +/- 0.56, P < .001, 95% confidence interval: -0.35, -0.67 mm). The mean cross-sectional area on the symptomatic side was significantly smaller than the area on the asymptomatic side in 27 of 31 patients (4.50 mm(2) +/- 1.75 and 6.28 mm(2) +/- 2.19, P < .001, 95% confidence interval: -2.41, -1.16 mm(2)). CONCLUSION: The results indicate that trigeminal nerve atrophy can be depicted noninvasively in patients with trigeminal neuralgia.     

3D-CISS序列MR成像在血管压迫性三叉神经痛中的应用

目的　探讨三叉神经痛患者的神经血管解剖关系。方法　应用 3D -CISS序列并结合 3D -TOF血管造影及MPR重建技术对 49例三叉神经痛患者进行MR检查并部分与手术结果对照。结果　 (1) 13例手术患者中 ,10例 3D -CISS和 3D -TOF序列均显示血管压迫的患者经手术证实为动脉压迫 ,另 3例仅在 3D -CISS序列显示的压迫血管 ,手术证实为静脉压迫。 (2 ) 2 0例伴有上颌神经症状的病人有 18例 (90 % )在三叉神经根部内侧有压迫点 ;19例伴有下颌神经症状的病人有 15例 (79% )在三叉神经外侧有压迫点 (经 χ2 检验 ,P <0 .0 0 1)。结论　 3D -CISS序列对显示三叉神经痛病人的神经血管关系、三叉神经的压迫部位与三叉神经痛区域相关性有重要作用。     

三叉神经受压位置的MRI与三叉神经痛的相关研究

目的：探讨三叉神经痛与血管压迫神经的位置关系。方法：回顾性分析50例有神经血管压迫症状患者的临床和MRI表现，其中40例有三叉神经痛，10例无三叉神经痛。结果：40例有三叉神经痛患者的MRI表现中35例（87．5％）显示血管压迫三叉神经根进入区（REZ）处，5例（12．5％）显示压迫三叉神经节前段（PGS）处；10例无三叉神经痛患者的MRI表现中4例（40％）显示压迫REZ处，3例（30％）显示压迫PGS处，3例（30％）显示压迫三叉神经门进入区（PEZ）处。结论：大部分三叉神经痛患者的神经血管压迫位于REZ处。     

低场强磁共振CBASS序列在三叉神经痛病因诊断中的应用价值

目的:探讨低场强MRI CBASS序列在三叉神经痛(TN)病因中的研究价值。方法:对50例TN患者依次采用CBASS序列,结合FE序列,FE3D-TOF序列进行检查,对CBASS序列成像MRI表现及手术结果作回顾性分析。结果:①50例TN患者中,肿瘤性病变7例,其它3例,排除上述继发性TN10例;40例原发性TN患者入选,疼痛侧MRICBASS序列发现有三叉神经血管压迫或接触29例(29/40),非疼痛侧有三叉神经血管接触9例(9/40),两组相比有显著性差异2=20.050,(P<0.0001);②50例患者均行手术治疗,CBASS序列对原发性TN诊断的敏感性为93.1%,特异性为81.8%,准确性90.01%,假阴性为18.21%,假阳性为6.9%。结论:三叉神经脑池段血管压迫或接触是TN的首要原因,CBASS序列成像能清晰显示三叉神经与邻近血管、肿瘤病变或其他病变之间的关系,对临床诊治具有重要指导意义。     

CT 定位扫描在伽玛刀治疗三叉神经痛中的应用

目的：探讨伽玛刀治疗三叉神经痛应用 CT 定位扫描的可行性。方法回顾性分析成都军区机关医院肿瘤科从2010年10月-2013年6月收治的因核磁扫描禁忌证而行 CT 定位的三叉神经痛患者12例,局麻下在前额隆突和枕骨粗隆以上水平安装定位框架,基环低于外耳孔下﹥1 cm,在 CT 定位扫描图像上寻找三叉神经根出桥脑处,行伽玛刀治疗：等剂量曲线50％,最高剂量84-90 Gy。术后电话随访,行疼痛缓解评级和面部麻木评级。结果按以上方法安装立体定位框架,很好地躲避金属伪影,CT 扫描图像中可显示三叉神经根。术后随访平均14（6-38）个月,11例（91.67％）疼痛分级从Ⅳ、Ⅴ级降低至Ⅲ级以下,其中6例（50.00％）疼痛完全缓解,平均起效时间6（3-10）个月。3例（25.00％）患者出现Ⅲ级以下面部麻木。结论在前额隆突和枕骨粗隆水平,基环低于外耳孔下﹥1 cm 的位置安装立体定位框架,可避免金属伪影,显示三叉神经根,满足伽马刀治疗定位的需要。CT 定位扫描可作为有核磁扫描禁忌证患者伽玛刀治疗的定位方式。     

3D-TSE序列在三叉神经痛病因诊断中的价值

目的　探讨MRI三维快速自旋回波 (3D TSE)序列在三叉神经痛 (TN)病因研究中的价值。资料与方法　应用 3D TSE序列 ,结合常规MRI序列 ,分析 5 0例TN患者和 5 0名正常对照者的MRI表现及手术结果。结果　 (1) 5 0名正常对照者 10 0侧脑池段三叉神经MRI检查中 ,11侧存在三叉神经血管接触。 5 0名TN患者疼痛侧有血管压迫或接触的为 32例 ,非疼痛侧 5 0侧三叉神经中 ,有血管接触的为 7例 ,经统计学分析 ,TN患者疼痛有无与是否存在血管压迫或接触有统计学意义 (P <0 .0 0 5 )。 (2 ) 5 0例TN患者疼痛侧 ,MRI诊断TN病因中血管压迫或接触占 6 4 % (32 / 5 0 ) ;肿瘤性病变占 16 % (8/ 5 0 ) ;其他占 2 0 % (10 / 5 0 )。 (3)根据手术结果 ,3D TSE序列对TN诊断的敏感性为 10 0 % ,特异性为 80 %。结论　三叉神经脑池段的血管压迫或接触是TN的主要病因 ,3D TSE成像能清晰显示三叉神经与邻近血管、肿瘤性病变或其他病变之间的关系 ,为临床确定治疗方案有重要的指导意义     

Acute effects of stereotactic radiosurgery on the kineties of glucose metabolism in metastatic brain tumors: FDG PET study

Hyperacute changes in the expression of glycolysis-associate gene products as well as FDG uptake in tumor cells after high-dose irradiation reflect response of the cells to noxious intervention and may be a potential indicator of the outcome of treatment. To understand acute effects on the kinetics of glucose metabolism of tumors in vivo after high-dose irradiation, we analyzed dynamic FDG PET data in patients with metastatic brain tumors receiving stereotactic radiosurgery. MATERIALS AND METHODS: We studied 5 patients with metastatic brain tumors by means of dynamic FDG PET before and 4 hours after stereotactic radiosurgery. Rate constants of glucose metabolism (K1*- k3*) were determined in a total of 13 tumors by a non-linear least squares fitting method for dynamic PET and arterial blood sampling data. Rate constants after radiosurgery were compared with those before radiosurgery. Changes in the rate constants induced by the therapy were also correlated with changes in tumor size evaluated by CT and/or MRI 6 months later. RESULTS: Four hours after radiosurgery, the phosphorylation rate indicated by k3* was significantly higher (0.080 +/- 0.058) than that before radiosurgery (0.049 +/- 0.023) (p < 0.05, paired t test), but there was no significant change in the membrane transport rates indicated by K1* and k2*. Although increases in the net influx rate constant K* (= K1*k3*/(k2* + k3*)) were correlated with increases in k3*, K* after radiosurgery (0.027 +/- 0.011) was not significantly different from that before the therapy (0.024 +/- 0.012). The reduction in the tumor size was correlated with k3* after radiosurgery. CONCLUSION: Acceleration of the phosphorylation process was demonstrated in vivo in metastatic brain tumors as early as 4 hours after stereotactic radiosurgery, as shown experimentally in vitro in a previous report. The phenomenon may be a sensitive indicator of cell damage.     

Study of facial neuralgia

So-called idiopathic, essential trigeminal neuralgia is characterised by typical severe pain in the territory of the trigeminal nerve or one of its divisions. This entity remains a diagnosis of exclusion after investigation by computerized tomography and/or magnetic resonance imaging of the path of the trigeminal nerve and its branches, to exclude any neoplastic, inflammatory, infectious or vascular process. Nevertheless, surgical exploration and now medical imaging have revealed in a large number of cases of "idiopathic" essential trigeminal neuralgia, compression of the trigeminal nerve as it emerges from the brainstem by a vascular loop.     

MRI volumetry for the preoperative diagnosis of trigeminal neuralgia

To assess whether quantitative measuring methods can help improve the reliability of MRI-based evaluations of the pathological role of a neurovascular conflict between an artery and the trigeminal nerve. In a prospective study, magnetic resonance images were obtained from 62 patients with unilateral facial pain and 50 healthy test subjects. In coronal T1- and T2-weighted sequences volume measurements were performed by regions of interest and compared intraindividually (healthy versus affected side in the patient populations and right versus left side in the group of test subjects) and on the basis of the different clinical pictures (t test for dependent and independent samples, p<0.05). In patients with trigeminal neuralgia, the affected nerve showed a smaller volume than the trigeminal nerve on the healthy side (p<0.001). Such a volume difference was noted neither in the other patients nor in the healthy test subjects. Quantitative MRI measurements allow a pathological neurovascular conflict to be distinguished from a nonpathological condition where an artery is in close proximity to the trigeminal nerve. The measured volume difference between the healthy and the affected nerve in patients with neuralgia is indicative of trigeminal nerve atrophy resulting from damage to the nerve.     

3T MR体层血管造影对血管压迫性三叉神经痛的诊断价值

目的:探讨3T磁共振体层血管造影(MRTA)对血管压迫性三叉神经痛的诊断价值.方法:回顾性分析60例手术治疗的血管压迫性三叉神经痛患者的MRTA表现,评判三叉神经周围有无血管压迫,并与术中观察结果对照.结果:症状侧血管压迫者52例,非症状侧血管压迫5例,两者差异有统计学意义(P＜0.01).MRTA显示的神经血管接触52例中,术中49例发现有血管压迫或接触,MRTA显示无接触的8例中有4例发现血管压迫或接触.以手术结果为金标准,MRTA判断血管压迫性三叉神经痛的敏感性、特异性、准确性、阳性预测值和阴性预测值分别为92.5％、57.1％、88.3％、94.2％和50％.结论:MRTA可以准确显示三叉神经根与周围血管的关系,为血管压迫性三叉神经痛的诊断及治疗提供可靠的影像学依据.