非小细胞肺癌精确放疗中三种CT扫描方法的研究

目的 比较自主呼吸控制(ABC)、自由呼吸(FB)状态下慢速CT扫描(SS)和常规轴位扫描在周围型非小细胞肺癌(NSCLC)精确放疗中减小放射性肺损伤方面的作用差异。方法 10例周围型NSCLC患者在适形放疗定位时分别采集3种CT图像:1FB时常规轴位扫描;2ABC螺旋CT快速扫描;3FB时慢速CT扫描。将3套图像传输至计划系统,分别制定3个适形放疗计划,比较3个计划的大体肿瘤靶区(GTV)、临床靶区(CTV)、计划靶区(PTV)、受照剂量>20 Gy的正常肺组织占全肺体积的百分比(V₂₀)及全肺平均受照剂量(D_mean)。结果 3个计划的GTV、CTV体积以慢速扫描似乎最大,ABC计划似乎最小,但差异无统计学意义(F=1.513,P=0.238;F=1.376,P=0.270);FB常规轴位计划的PTV体积最大,且分别与另2个计划间差异有统计学意义(F=26.148,P=0.000);V₂₀、D_mean在FB常规轴位计划均最大,且FB计划和另2个计划间差异有统计学意义(F=7.623,P=0.002;F=18.217,P=0.000)。结论 相对于FB状态,使用ABC或慢速CT扫描可有效减少周围型NSCLC精确放疗中正常组织的受照体积和剂量,减小放射性肺损伤的发生率。     

RapidArc联合主动呼吸控制技术应用于胸段食管癌调强放疗的剂量学研究

目的 探讨RapidArc联合主动呼吸控制(ABC)技术在胸段食管癌调强放疗的剂量学特点.方法 选取10例接受放疗的胸段食管癌患者,在ABC辅助下选择吸气末屏气触发方式(mDIBH),触发阈值设定为呼吸曲线峰值的80％,和自由呼吸(FB)状态下分别行定位CT扫描,应用三维治疗计划系统为每例患者设计FB下的IMRT(IMRT-FB)和双弧RapidArc( Arc-FB)、mDIBH下的3个小弧RapidArc( Arc-A BC)3种调强放疗计划.评价靶区的D2％、D98％、V95,均匀指数(HI)和适形指数(CI),正常组织的相关剂量体积参数Vx,以及总机器跳数(MU)、总控制点数( control points)和治疗时间.结果 PTV的平均体积由FB下的376 cm3减少到了mDIBH下的260cm3.mDIBH下的双肺平均体积为5964.6 cm3,而FB则为3838.8 cm3,增加了35％;mDIBH和FB状态下平均心脏体积分别为524.4和642.7 cm3.Arc-ABC计划靶区的CI、HI及D2％、D98％、V95与IMRT-FB和Arc-FB计划差异无统计学意义,双肺的V10、V20、V30、V40及平均剂量(Dmean)明显低于IMRT-FB和Arc-FB(F=4.38、5.34、4.07、3.89、4.28,P＜0.05),心脏的V20、V30、V40、Dmean及脊髓Dmax有不同程度的下降,但差异无统计学意义.Arc-ABC计划的总机器跳数和子野数也明显少于IMRT-FB计划(F=26.86、12.56,P＜0.05).结论 RapidArc联合ABC在胸段食管癌精确放疗中具有提高靶区剂量和降低肺组织受照剂量的作用.     

基于四维CT探讨腹部加压对周围型肺部肿瘤立体定向放疗靶区位移及外扩边界的影响

目的基于四维CT(4DCT)探讨腹部加压对周围型肺部肿瘤立体定向放疗(SBRT)靶区位移幅度、靶区体积大小及外扩边界的影响。方法前瞻性收集拟行SBRT的周围型肺部肿瘤患者,CT模拟定位时依次完成腹部加压3DCT、腹部加压4DCT(4DCT_com)、自由呼吸4DCT(4DCT_free)扫描,并于照射前行腹部加压锥形束CT(CBCT_com)扫描。4DCT图像重建生成最大密度投影(MIP)图像。在上述图像上分别勾画大体肿瘤体积(GTV)并重建肿瘤内大体靶体积(IGTV),在IGTV MIP_com基础上分别均匀外扩5、4、3 mm构建计划靶区(PTV)MIP_com。按所在肺叶位置将肿瘤分为全组、肺上中叶组和肺下叶组。结果对于全组肿瘤靶区,与自由呼吸状态比较,加压使靶区中位三维运动矢量减少30.92%;对于肺上中叶和下叶靶区,加压分别使靶区中位三维运动矢量增加3.42%和减少18.80%。无论全组还是上中叶或是下叶组,肿瘤各方向位移及三维运动矢量差异均无统计学意义(P>0.05)。腹部加压使IGTV的体积显著减少,IGTV MIP_com、IGTV MIP_free和IGTV10_com、IGTV10_free中位体积分别为4.01、5.36 cm³和6.59、7.65 cm³,差异均有统计学意义(Z=-3.45、-3.14,P<0.01)。PTV MIPcom外扩5 mm时IGTV CBCT_com对PTV MIP_com的包含度为100%,外扩4、3 mm时包含度≥95%的比例分别为100%、83.33%。结论腹部加压技术改变了患者呼吸模式,减少腹式呼吸的同时增加了胸式呼吸;IGTV MIP和IGTV10的体积减小,为SBRT患者PTV的缩小创造了条件;临床上采用腹部加压技术实施SBRT时基于4DCT的IGTV外扩4 mm形成的PTV显示了临床精准放疗的趋势。     

基于3D-CT与4D-CT定义的非小细胞肺癌计划靶区比较

目的 探讨基于3D-CT轴位扫描所定义的计划靶区(PTVvector)与基于4D-CT定义的计划靶区(PTV4D)的位置和体积差异.方法 适合三维适形放疗(3D-CRT)的非小细胞肺癌(NSCLC)患者共28例,其中,16例肿瘤位于肺上叶为肺上叶组,12例肿瘤位于肺中下叶为肺中下叶组,均于同次CT模拟定位时序贯完成胸部常规3D-CT轴位扫描和4D-CT扫描.基于3D-CT图像GTV及其运动矢量定义PTVvector:GTV外扩7 mm形成CTV,在CTV基础上依据4D-CT测得的肿瘤三维运动矢量均匀外扩形成ITVvector,然后再外扩3 mm,形成PTVvector;基于4D-CT图像各时相GTV融合定义PTV4D:10个时相的GTV分别外扩7 mm形成各时相的CTV,10个时相的CTV融合形成ITV4D,ITV4D外扩3 mm形成PTV4D.对比PTVvector和PTV4D靶区位置、体积及包含度差异,分析三维运动矢量和相关参数的相关性.结果 肺上叶和肺中下叶两组肿瘤中心三维运动矢量中位数分别为2.8和7,0 mm,差异有统计学意义(z=-3.485,P<0.05).肺上叶组PTVvector和PTV4D中心点坐标仅在x轴上差异有统计学意义(z=-2.010,P<0.05),肺中下叶组两靶区中心点坐标仅在;轴上差异有统计学意义(z=-2.136,P<0.05).肺上叶组PTV4D与PTVvector比值的中位数为0.75,肺中下叶组为0.52,两比值与肿瘤三维运动矢量的相关性差异均有统计学意义(r=-0.638、-0.850,P<0.05).PTVvector与PTV4D彼此间包含度的中位数分别为66.39%和99.55%,两者与肿瘤的三维运动矢量相关性差异有统计学意义(r=-0.814、0.613,P<0.05).结论 基于4D-CT定义的PTV4D明显小于基于3D-CT定义的PTVvector,两者的比值及相互包含度均与肿瘤三维运动矢量显著相关.     

主动呼吸控制和四维CT技术在肺部肿瘤立体定向放射治疗中的应用

目的 探讨深吸气屏气-主动呼吸控制（ABC）和四维CT（4D-CT）技术在肺部肿瘤立体定向放疗（SBRT）中的肺、靶体积差异和剂量学特征。方法 选取10例肺部肿瘤患者,分别行自由呼吸状态下CT扫描（FB-CT）,4D-CT和ABC状态下CT扫描（ABC-CT）。采用SBRT技术在同等条件下,分别设计4组计划,FB-CT、ABC-CT、4D-CT和4D-CT时相中吸气末CT0（4D-CT0）计划,统计分析双肺体积（V）、计划靶区体积（PTV）、双肺接受5 Gy的体积（V₅）、双肺接受20 Gy的体积（V₂₀）、平均肺剂量（MLD）和正常组织并发症概率（NTCP）等指标。结果 与FB-CT计划相比,ABC-CT计划的V、PTV、V₅、V₂₀、MLD和NTCP增减分别为51.48%、-65.34%、-42.64%、-56.62%、-40.22%和-98.53%（t=-7.14~6.16,P<0.05）;4D-CT计划的PTV、V₅、V₂₀、MLD和NTCP增减分别为-40.14%、-16.90%、-37.16%、-17.85%和-90.96%（t=0.54~3.22,P<0.05）;4D-CT0计划的PTV、V₅、V₂₀、MLD和NTCP增减分别为-68.98%、-30.21%、-48.49%、-37.45%和-95.82%（t=1.32~5.46,P<0.05）;4D-CT和4D-CT0与FB-CT计划相比,两者的双肺体积差异均无统计学意义（P>0.05）。结论 ABC-CT方式与其他方式相比,其双肺绝对体积更大,影像伪影小,靶区匹配精度高,显著降低正常肺组织照射剂量。     

磁共振弥散加权成像在食管癌放疗中的应用价值

 目的 探讨CT图像和CT/MR弥散加权成像(diffusion weighted imaging,DWI)图像融合在食管癌靶区勾画中的应用价值。方法 收集2017-08至2018-12医院收治的26例食管鳞癌患者,进行常规CT扫描及 MR DWI,扩散敏感梯度b值取为600 s/mm²,分别在CT图像和CT/MR DWI融合图像上勾画食管原发肿瘤大体体积(gross tumor volume,GTV)和PTV,计算GTV和PTV的长度,并利用TiGRT治疗计划系统获得GTV与PTV体积,以同样的处方剂量及危及器官限制剂量分别在两种图像上制定治疗计划,比较不同计划的GTV和PTV长度、体积、处方剂量和危及器官的剂量差异。结果 两种条件下计划的剂量分布和各项参数均达到了临床处方剂量要求。而在CT/MR DWI计划下的PTV、GTV的长度和体积均小于CT计划(P=0.00、0.00、0.01、0.03)。基于DWI计划的危及器官肺部平均剂量明显低于CT计划(P=0.00)。结论 DWI在食管癌放疗中的应用更精确,能够保护正常组织。     

不同活度125I粒子植入后不同时间肿瘤吸收剂量对比

目的 探讨周边剂量相同时不同活度125I粒子植入后不同时间点肿瘤吸收剂量的差异.方法 利用计算机三维治疗计划系统(3D-TPS)勾画出边长3.5 cm正方体模拟肿瘤,分别载入125I粒子0.8 mCi(A组)、0.3 mCi(B组)并周边分布,处方剂量145 Gy,得出剂量-体积直方图(DVH)及100％靶体积吸收剂量(D100)、90％靶体积吸收剂量(D90)、150％处方剂量覆盖的体积占靶体积百分比(V150)、90％处方剂量覆盖的体积占靶体积百分比(V90)、最高剂量点等指标.根据125I粒子衰变规律公式,分别计算A、B组粒子植入后1、2、3、4、5、6个月时粒子活度,计算两组粒子植入后各时间点肿瘤实际吸收剂量,比较两组各时间点肿瘤实际吸收剂量、D100、D90、V150 V90最高剂量点等指标.结果 A组、B组粒子植入后1、2、3、4、5、6个月时肿瘤实际吸收剂量均值相同,均为(81.43±46.20) Gy;D100分别为(49.14±34.65) Gy、(38.86±27.43) Gy,差异有统计学意义(P=0.009);D90均为(64.57±46.20) Gy;V150分别为(7.96±8.62)％、(7.58±10.65)％,差异无统计学意义(P=0.398);V90分别为(25.83±35.76)％、(26.16±35.97)％,差异无统计学意义(P=0.866);最高剂量点分别为(798.29±568.07) Gy、(359.29±256.36) Gy,差异有统计学意义(P=0.010).结论 周边剂量相同时125I粒子植入后不同时间点肿瘤吸收剂量相同,粒子活度对肿瘤吸收剂量速率无影响,高活度组粒子靶区内最高剂量点明显高于低活度组,高剂量区持续时间较长于低活度组.     

RapidArc进行肝癌放疗时不同靶区确定方法的剂量学比较

目的 研究应用RapidArc进行原发性肝癌(HCC)放射治疗时不同靶区确定方法的剂量学差异.方法 选取10例HCC患者,完成4D-CT、自由呼吸(FB)下3D-CT、主动呼吸控制(ABC)辅助平静吸气末屏气(EIH)下3D-CT扫描;将4D-CT依据呼吸周期分割为10套CT图像.分别在不同CT图像上手动勾画GTV,将4D-CT的10个GTV融合为内靶区1(IGTV1),测量GTVFB到IGTV1的外放距离,并将所得外放距离应用于GTVFB获得内靶区2(IGTV2).GTVFB、IGTV1、IGTV2、GTVEJH依据不同外放获得PTV-1～ PTV-4,针对不同PTV制定相应RapidArc计划(RA1～RA4),其中RA1、RA2 、RA3采用单个358°全弧,RA4采用3个135°弧,比较不同计划间剂量学差异.结果 PTV-1、PTV-3体积大于PTV-2、PTV-4,其中PTV-1/PTV-2、PTV-l/PTV-4平均为2.5、1.9.4个RA计划的适形指数、均匀性指数、靶区最大剂量、最小剂量之间的差异均无统计学意义.与RA1、RA3比较,RA2、RA4的正常肝脏平均剂量从10.21Gy(RA1)、9.62 Gy( RA3)降低到8.23 Gy(RA2)、7.63 Gy( RA4)(x2=l0.68,P＜0.05),V30从7.76％ 、6.12％降低到5.24％、5.05％(x2=14.76,P＜0.05).4种RA计划胃和十二指肠受量间的差异均无统计学意义.结论 应用RapidArc进行HCC放射治疗时,相对于传统外放标准,4D-CT技术或ABC技术均可在保证靶区准确的基础上完成照射剂量;两者在正常肝脏保护方面的作用基本相当.     

两种放疗计划系统用于鼻咽癌螺旋断层调强放疗计划的剂量学比较

目的比较Ray Station 7(V6.99)和螺旋断层放射治疗(TOMO)(Hi-Art@V5.1.3)2种放疗计划系统设计鼻咽癌螺旋断层调强放疗计划的剂量学差异。方法回顾性分析2018年5至12月于中山大学肿瘤防治中心完成TOMO治疗计划的15例鼻咽癌患者的临床资料, 其中男性11例、女性4例, 年龄(44.0±17.7)岁, 按照与TOMO治疗计划系统相同的计划设置参数和临床剂量学的要求, 在Ray Station 7治疗计划系统中设计TOMO计划。比较2种治疗计划系统设计的计划质量, 分析100%、95%处方剂量覆盖靶区的体积占靶区总体积的百分比(V100、V95), 覆盖靶区1%、98%、99%体积的剂量(D1%、D98%、D99%), 均匀性指数(HI)和适形指数(CI), 重要危及器官的剂量学指标, 计划优化时间和计划执行时间。符合正态分布的计量资料的组间比较采用配对样本t检验的双侧检验。结果 Ray Station 7和TOMO计划的鼻咽癌原发病灶的计划靶区(PTVnx)的V100[(97.5±2.1)%对(94.9±3.9)%], 原发病灶侵犯区域的计划靶区(PTV...     

非小细胞肺癌三维适形放射治疗的关键预后因素:大体肿瘤体积

三维适形放射治疗(3D-CRT)可以改进描画靶区体积等剂量线的能力,可以选择射束角度,得到更精确的剂量分布,成为非小细胞肺癌病人(NSCLC)治疗重要进展的代表。该研究分析采用3D-CRT的NSCLC的长期结果,确定与采用该技术相关的特定预后因子。 选择1991年3月-1998年12月间207例不能手术的NSCLC病例进行 3D-CRT。肿瘤的直径为 1～11cm,由CT数据决定的大体肿瘤体积(GTV)范围为2～759cm~3,计划靶体积(PTV)从21～1095 cm~3。使用三维放射治疗计划系统(3D-RTP)。进行整个胸部和上腹部CT扫描,未行呼吸控制。采用北卡罗莱那州大学计算机小组开发的软件描绘GTV,临床靶区     

Stress MR imaging for evaluation of popliteal artery entrapment

The popliteal artery entrapment (PAE) syndrome has been recognized as a cause of arterial occlusion in young people. It is the result of an anomaly of the relationship between the popliteal artery and the gastrocnemius muscle. Eight young healthy volunteers (16 legs) and six patients (10 legs) with suspected PAE underwent magnetic resonance (MR) imaging. Gradient-echo images were obtained in axial planes with the leg at rest and during active plantar flexion against resistance. Imaging at rest allowed identification of PAE signs in only one leg, which had an anomalous medial course of the popliteal artery. In the other cases, only the stress technique was able to show signal loss in the popliteal artery due to muscular compression (two legs) or the presence of accessory muscle slip around the vessel (two legs), as confirmed at surgery. MR imaging is therefore a useful technique for the diagnosis of PAE because of its capability of combining information obtainable with other modalities.     

MR imaging of muscle and tender points in fibromyalgia

Fibromyalgia is a syndrome manifested by chronic, diffuse muscu-loskeletal aching and soreness, palpable muscle tender points, and other symptoms. Standardized clinical diagnostic criteria have recently been developed. Skeletal muscle has been postulated as the end organ in this disease. Biochemical, histologic, electromyographic, and conventional radiographic studies have demonstrated no definitive abnormality. This study sought to establish whether magnetic resonance (MR) imaging could demonstrate any abnormality in these patients. Eighteen patients were entered in the study, 14 of whom were able to complete their examinations. T1 -weighted, T2-weighted, gradient-echo, and STIR (short-tau inversion-recovery) sequences were performed in all patients, with selected patients examined with T1weighted, gadopentetate dimeglu-mine-enhanced sequences. The trapezius and suboccipital regions were imaged in patients who, clinically, had active fibro-myalgia. No abnormalities could be detected. The authors conclude that the conventional MR imaging used in this study was unable to depict any primary skeletal muscle abnormality in fibromyalgia.     

MR imaging of disorders of the brachial plexus

The authors evaluated 64 consecutive patients with suspected brachial plexus (BP) abnormalities of diverse cause with magnetic resonance (MR) imaging, using the body coil and a standardized protocol. Of the 43 patients for whom follow-up was available, 25 were suspected of having neoplastic involvement of the BP, nine had sustained injuries, and nine presented with BP symptoms of uncertain cause. MR imaging was 63% sensitive, 100% specific, and 77% accurate in demonstrating the abnormality in this diverse patient population. When patients with neoplastic and traumatic disorders were considered separately, sensitivity increased to 81%, accuracy to 88%, and specificity remained unchanged. In the patients with a clinical diagnosis of idiopathic or viral plexitis, the MR imaging findings were normal, serving to exclude other structural abnormalities. It is concluded that MR imaging is valuable in the assessment of a wide range of BP disorders.     

MR angiography of congenital heart disease: Value of segmented two-dimensional inflow technique and maximum-intensity-projection display

Magnetic resonance (MR) angiography of the cardiovascular system was evaluated in 41 patients with congenital heart disease by using a two-dimensional (2D) inflow technique based on a magnetization-prepared gradient-echo pulse sequence with segmented k-space data acquisition and electrocardiographic gating at 0.5 T. Inversion and saturation prepulses were used to suppress stationary tissue and enhance intravascular signal. Presaturation slabs were applied where certain vascular structures had to be suppressed. Sequence parameters were optimized by evaluating signal intensity and contrast characteristics for various flip angles and inversion and saturation delay times. The heart and intrathoracic vasculature were encompassed with 40–50 overlapping sections. Both 2D angiograms and maximum-intensity-projection images were evaluated. Combining data sets acquired in the sagittal and transverse orientations provided the most satisfactory information about the pulmonary arteries. The highest signal-to-noise ratios were obtained with a flip angle of 65° and short prepulse delay times. Two-dimensional MR angiography can provide useful diagnostic information but requires a thorough understanding of in-plane and hemodynamically induced signal intensity changes.     

MR imaging characteristics of noncancerous lesions of the prostate.

Radical prostatectomy specimens from 53 men with clinical stage A or B prostate cancer were retrospectively reviewed and compared with correlative axial T2-weighted magnetic resonance (MR) images obtained just before surgery. Non-cancerous lesions were evaluated for signal intensity and location. Focal high-signal-intensity areas (n = 72) were present in 81% of patients. The 26% of lesions seen in the central gland all correlated with cystic atrophy. Of the 53 lesions seen in the peripheral prostate, 47 (89%) were cystic atrophy without associated cancer, four (7.5%) cystic atrophy with cancer, and two (3.8%) focal inflammation. Focal low-signal-intensity areas (n = 42) were present in 60% of patients. Of the 31% of lesions in the central prostate, one-fifth correlated with benign prostatic hyperplasia (BPH) and four-fifths with fibrous tissue. Of the 69% of peripheral lesions, 83% corresponded to fibrous tissue, 10% to BPH, and 7% to normal tissue. Mixed lesions (n = 42) were present in 64% of patients; 86% of these were located centrally and 14% peripherally. All mixed central lesions were BPH; the peripheral lesions were areas of combined cystic atrophy and fibrosis. BPH of low or mixed signal intensity can extend into the peripheral prostate and mimic cancer. High-intensity cystic atrophy associated with cancer can mimic normal tissue.     

肾细胞癌的MRI研究进展

肾细胞癌是最常见的成人肾脏恶性肿瘤。近年来，多种功能MRI成像技术（如扩散加权成像、灌注加权成像等）、多参数MRI联合分析以及影像组学等新兴影像处理技术被证实在肾细胞癌的诊断中具有较大的价值。目前，研究热点多集中于良恶性肿瘤的鉴别、组织学亚型的区分、肿瘤分期、预测核分级及判断预后。就MRI新技术及图像处理技术在肾细胞癌中的研究进展予以综述。     

Dynamic contrast-enhanced MR imaging assessment of vascularized free fibular grafts

Magnetic resonance (MR) imaging may be a noninvasive method for assessing perfusion of vascularized bone grafts placed for treatment of avascular necrosis. One proximal femur of seven beagles was devascularized, with insertion of a vascularized fibular graft. MR imaging at 1 week (seven dogs) and 6 weeks (five dogs) after surgery included pre- and postcontrast spin-echo sequences, unenhanced twodimensional time-of-flight (TOF) vascular imaging, and dynamic gradient-echo imaging during infusion of gadolinium. Relative signal intensity values of selected regions obtained from the dynamic gradientecho images were plotted as percent enhancement versus time. In the operated hip, MR imaging did not show enhancement in six of seven femoral heads and greater trochanters at 1 week after surgery, with similar results after 6 weeks. MR imaging of fibular grafts 6 weeks after surgery showed an initial rapid increase in enhancement and a subsequent slower increase in five of five dogs, although no enhancement was seen in six of seven dogs at 1 week. These findings contrasted with a rapid initial increase in enhancement followed by slow decline in non-operated hips. Two-dimensional TOP imaging did not show the vascular pedicle of the graft in any dog. Findings of radionuclide bone scanning performed 1 week after surgery were consistent with devascularization of the operated femur and fibular graft. However, tetracycline distribution and histologic findings confirmed the viability of five of five grafts within the devascularized femurs 6 weeks after surgery. Thus, dynamic contrast-enhanced MR imaging at 6 weeks after surgery is valuable for assessing vascular bone graft perfusion, while similar imaging at 1 week may suggest otherwise.     

Influence of in vivo copper on MR images of the liver in rats

To investigate the effects of in vivo copper on magnetic resonance (MR) images, the authors studied Long-Evans cinnamon rats, which develop hepatitis and hepatocellular carcinoma as a result of abnormal copper metabolism. The livers of the rats were imaged before hepatitis developed; the absence of hepatic disease was confirmed histopathologically. The copper that accumulated in the liver of the rats was thought to exist in the form of divalent ions, which were suspected of reducing the T1 and T2 of neighboring protons. However, the signal intensities of the liver on T1- and T2*-weighted images did not change, suggesting that in vivo copper, even when accumulated abnormally, does not influence the signal intensity of MR images.     

Localized proton MR spectroscopy of the brain in children

Small-voxel (3.0–8.0 cm³), magnetic resonance (MR) imaging–guided proton MR spectroscopy was performed in 54 patients (aged 6 days to 19 years) with intracranial masses (n = 16), neurodegenerative disorders (n = 34), and other neurologic diseases (n = 4) and in 23 age-matched control subjects without brain disease. A combined short TE (18 msec) stimulatedecho acquisition mode (STEAM) and long TE (135 and/or 270 msec) spin-echo point-resolved spatially localized spectroscopy (PRESS) protocol, using designed radio-frequency pulses, was performed at 1.5 T. STEAM spectra revealed short T2 and/or strongly coupled metabolites; prominent resonances were obtained from N-acetyl aspartate (NAA), choline-containing compounds (Cho), and total creatine (tCr). Lactate was well resolved with the long TE PRESS sequence. Intracranial tumors were readily differentiated from cerebrospinal fluid (CSF) collections. All tumors showed low NAA, high Cho, and reduced tCr levels. Neurodegenerative disorders showed low or absent NAA levels and enhanced mobile lipid, glutamate and glutamine, and inositol levels, consistent with neuronal loss, gliosis, demyelination, and amino acid neuro-toxicity. Preliminary experience indicates that proton MR spectroscopy can contribute in the evaluation of central nervous system abnormalities of infants and children.     

Percutaneous needle biopsy of the spine

The purpose of this review article is to provide a brief overview of the recent literature on the two main types of percutaneous biopsy methods done in the spinal column: fine needle aspiration biopsy (FNAB) and core needle biopsy (CNB). FNAB is the process of obtaining a sample of cells and bits of tissue for examination by applying suction through a fine needle attached to a syringe. Core needle biopsy involves extracting a cylindrical sample of tissue using a large, hollow needle. The decision for needle biopsy is a joint effort between the clinician, pathologist, radiologist, surgeon, and patient. Specific techniques and approaches with varying needle systems are described for each spinal region. Percutaneous image-guided spine biopsy is a safe and effective procedure. It is the procedure of choice in definitive diagnosis of pathologic lesions of the spine.