心脏磁共振分形分析评估肥厚型心肌病心肌小梁特征的初步研究

目的 探讨心脏磁共振分形分析技术评价肥厚型心肌病(HCM)左心室心肌小梁复杂性的可行性,研究小梁复杂性与左心室心功能的关系。资料与方法 回顾性分析2020年8月—2022年12月南昌大学第二附属医院收治的80例HCM患者和80名志愿者(对照组)。测量HCM组与对照组心功能参数及左心室心肌小梁分形维数(FD),比较两组左心室整体FD、最大基底FD、最大心尖FD的差异,采用受试者工作特征曲线评价FDs诊断HCM的效能,分析FDs与左心结构及功能参数的相关性。结果 HCM组左心室整体FD高于对照组,差异有统计学意义(1.303±0.047比1.229±0.026;t=12.387,P<0.001)。左心室整体FD鉴别HCM与对照组的诊断效能最佳,以1.251为诊断HCM的最佳截断值时,曲线下面积为0.933(95%CI0.896～0.969)。左心室整体FD与最大室壁厚度及心肌质量指数呈正相关(r=0.686、0.687,P<0.001),平均心尖FD与左心室射血分数呈正相关(r=0.520,P<0.001)。结论 心脏磁共振分形分析技术得到的FD对诊断HCM有明确价值,并...     

高血压患者左心室舒张功能与左心房几何重构的相关性研究

目的 :应用超声心动图探讨高血压病左心室不同舒张功能状态与左心房几何重构的相关性。方法 :收集高血压患者130例,高血压病患者根据左心室舒张充盈状态分级分为4组(舒张功能正常组30例,舒张功能降低组35例,假性正常化组35例,限制性充盈障碍组30例)。同时收集健康受检者60例作为对照组。应用超声心动图检测左心室射血分数(LVEF)在正常范围时,测量左心房离心指数(LAEI)评价左房几何重构;并测量二尖瓣口舒张早期流速峰值(E峰)与二尖瓣环舒张期早期运动速度Em峰比值(E/Em),E峰与M型峰值血流速度Vp比值等左心室舒张功能相关参数。结果 :随着左室舒张充盈状态分级的增加,LAEI逐渐降低,而E/Em、E/Vp增大(P0.05);LAEI与E/Em、E/Vp均呈负相关(r=-0.72;r=-0.67)。结论:在LVEF值正常情况下,左心房几何重构与左心室舒张充盈状态密切相关,LAEI可作为临床评价左心室舒张充盈状态的敏感参考指标。     

心脏MR初始T1值及组织追踪技术在心肌淀粉样变和肥厚型心肌病的初步应用价值

目的:探讨磁共振初始T1值及组织追踪技术(CMR-TT)在鉴别心肌淀粉样变(CA)和肥厚型心肌病(HCM)中的价值。方法:对14名CA患者、16名HCM患者及16名健康受试者行3.0T心脏磁共振检查,测量基底部、乳头肌部及心尖部心肌初始T1值,采用CMR-TT技术测量左心室三维(3D)整体纵向应变(GLS)、周向应变(GCS)及径向应变(GRS),描绘左心室心肌应变曲线。采用受试者操作特征曲线(ROC)评估初始T1值及各应变指标对CA和HCM的鉴别诊断价值。结果:CA组总体、基底部、乳头肌部、心尖部心肌初始T1值[分别为(1455.68±153.23)ms、(1446.97±170.53)ms、(1442.31±151.92)ms、(1468.31±141.83)ms]高于HCM组[分别为(1329.14±40.19)ms、(1329.45±46.14)ms、(1330.04±41.49)ms、(1327.41±46.55)ms],差异有统计学意义(P均<0.001)。CMR-TT应变分析结果示,CA组3D GRS(14.08±4.22)、3D GCS(-13.69±2.50)均低于HCM组(3D GRS、3D GCS分别为26.87±13.45,-17.23±4.76,P均<0.05)。ROC曲线显示心肌初始T1值(整体、基底部、乳头肌部、心尖部AUC分别为0.866、0.821、0.839、0.866,P均<0.001)鉴别诊断效能优于各应变参数[3D GLS(AUC=0.661,P=0.12)、3D GCS(AUC=0.786,P=0.003)、3D GRS(AUC=0.786,P=0.003)]。三组受试者左心室应变曲线下降的趋势不同:CA组呈“缓升-缓降-速降”表现,HCM组呈“缓升—速降”表现,而健康对照组则呈“速升—速降”表现。结论:初始T1值及3D GRS、3D GCS对于CA和HCM有较高的鉴别诊断价值。     

兔急性心肌梗死后左心室重塑的MRI研究

目的 观察兔急性心肌梗死( AMI)后心功能随时间演变的规律,探讨MRI影像特征及心功能指标的变化与左心室重塑的关系.方法 日本长耳白兔45只,采用开胸结扎法建立心肌梗死模型.分别于术后即刻(0周)和术后1、2、4、6、8周共6个时间点行在体MR检查,测定各项心功能指标,包括:左心室舒张末期容积(EDV)、每搏输出量(Sv)、射血分数(EF)、射血率峰值(PER)、充盈率峰值(PFR).比较心肌梗死后心功能参数随时间变化的规律.在每个时间点随机取5只动物的心脏离体标本,行MR扩散张量成像(DTI),测量ADC值、各向异性分数(FA)值.不同时间点的心功能参数组间比较采用重复测量方差分析,各时间点梗死区心肌及不同区域心肌的FA值与ADC值的比较采用单因素方差分析,相邻2组均数的比较采用LSD-t检验.结果 随着梗死时间的延长,左心室EDV呈现增加趋势,由术前的(2.21±0.35) ml增加到术后8周时的(3.15±0.57)ml,但差异无统计学意义(F=1.384,P =0.220).EF则由(57.31±11.11)％下降至(34.71±8.72)％,呈明显下降趋势,差异有统计学意义(F =27.134,P=0.001).EF随着EDV增加呈现下降趋势,线性回归分析得出一次方程:y=- 5.58x± 57.7 (F=8.855,P=0.005).随梗死时间的延长,PER由(27.31±13.06) ml/s下降至(17.31±6.41) ml/s (F=2.105,P=0.037),而PFR则由(23.79±14.15) ml/s下降至(12.07±6.91) ml/s (F =2.366,P=0.011).梗死区FA值随着梗死时间的延长而下降,由0.442±0.093下降至0.107±0.037(F=12.61,P=0.001),而ADC值则由(5.07±1.15)×10-4 mm2/s上升至(6.39±0.78)×10-4 mm2/s(F=4.166,P=0.022),差异均有统计学意义.梗死区、边缘区和外围区的FA值分别为0.201±0.049、0.316±0.127、0.323 ±0.117,ADC值分别为(6.19±1.78)×10-4、(5.44±2.63)×10-4、(5.29±2.02)×10-4 mm2/s,差异均有统计学意义(F=3.896,P =0.004;F =3.248,P=0.018).FA、ADC值在梗死区与边缘区比较差异均有统计学意义(t=7.327,P=0.001:t =3.292,P=0.005),而边缘区和外围区的FA值、ADC值的差异无统计学意义(t=1.024,P=0.129;t=1.467,P=0.164).结论 MR心功能测定可以动态监测AMI后心室功能性重塑过程,通过DTI可以反映心室结构性重塑过程的心肌微观察结构的改变.MRI可以作为心肌梗死后左心室重塑的一种可行性的评价方法.     

心脏超声造影测量肺循环时间评估心力衰竭患者左心室充盈压升高的价值

目的 探讨应用心脏超声造影测量肺循环时间（PTT）及肺血量（PBV）评估心力衰竭患者左心室充盈压升高的价值。资料与方法 回顾性分析2019年2月—2021年10月解放军总医院第四医学中心心内科收治的慢性心力衰竭患者76例，根据左心室舒张功能评估指南分为左心室充盈压正常组（n=41）和左心室充盈压升高组（n=35），同时选择健康对照30例，所有受检者行常规超声和心脏超声造影，测量左心室射血分数（LVEF）、左心室舒张末期容积（LVEDV）、左心室舒张末期内径（LVEDD）、左心房容积指数（LAVI）、三尖瓣反流速度及压差、左心室舒张早期充盈速率（E）、组织多普勒二尖瓣环舒张早期运动峰值速度（e’）等，测定对比剂PTT并计算PBV。比较3组超声参数、PTT及PBV的差异。分析PTT、PBV与各参数的相关性；采用受试者工作特征曲线评价PTT、PBV预测左心室充盈压升高的效能。结果 对照组、左心室充盈压正常组、左心室充盈压升高组间比较，PTT依次延长，PBV增多，LVEF减低，LVEDV、LVEDD、LAVI、E/e’增大（F=22.93、12.01、103.85、23.15、51.40、35...     

心脏再同步化治疗慢性心衰的短期疗效观察

目的 观察心脏再同步化治疗慢性心力衰竭(CHF)的短期临床疗效.方法 26例慢性心力衰竭患者行双心室再同步起搏治疗,全部患者均经冠状静脉窦植入左心室导线1根至心脏静脉,术后随访13.8±10.4(3～34)个月,观察心功能,患者活动度及夜间心率、QRS波时限,左心室收缩、舒张末内径,左室收缩、舒张末容积,左心室射血分数,左室舒张充盈时间,左室内各室壁收缩期达峰时间等.结果 26例患者中,1例于术后2个月时猝死;25例于术后3个月随访时发现心功能改善,有效率96.2%,心功能NY-HA分级,从Ⅲ-Ⅳ级改善为Ⅱ-Ⅲ级,患者活动度从0.31±0.40h/d增加至2.35±1.20h/d,夜间心率由84.8±15.7/min降低至63.4±4.5/min,心律变异性从47.3±7.1ms提高至96.4±15.1ms,QRS波从158.6±31.8ms缩短至129.5±30.2ms(P＜0.05),左心室收缩末内径、舒张末内径分别从67.6±8.2mm、77.0±9.4mm缩小至62.1±12.3mm、71.6±8.7mm(P＜0.05),左心室收缩末容积、舒张末容积分别从213±54ml、266±68ml缩小至151±62ml、212±63m1(P＜0.05),左心室射血分数从21.2%±4.5%提高至32.5%±6.4%(P＜0.05),左室舒张充盈时间从329±140ms提高至423±118ms(P＜05),左室12个节段收缩达峰时间标准差(Ts-Sd-12)从48.4±17.9ms减少至33.5±19.7ms(P＜0.05).结论 双心室再同步起搏是慢性心力衰竭治疗的有效方法.     

定量组织速度成像评价模拟失重对人体左心室舒张功能的影响

目的 应用超声心动图定量组织速度成像(QTVI)技术,观察模拟失重对人体左心室舒张功能的影响,探讨QTVI技术在评价中长期航天飞行后航天员左心室舒张功能的应用价值.方法 16名健康青年男性志愿者,-6°头低位连续卧床21 d,分别于卧床前(平卧位)、-6°头低位卧床第10天和20天分3次行超声心动图检查,应用QTVI技术获取心尖四腔、心尖左室两腔和心尖左室长轴观,选定左心室壁各节段心肌运动速度曲线,测量舒张早期波速度峰值(Ve)和舒张晚期波速度峰值(Va),计算Ve/Va,并进行统计学分析.结果 ①Ve:-6°头低位卧床10 d、20 d左心室壁绝大多数节段心肌舒张早期波运动速度下降(F=3.351～16.741,P＜0.05或P＜0.01),且随卧床时间延长,下降更为明显.②Va:-6°头低位卧床第10天、20天与卧床前对照组比较,左心室壁大部分节段心肌舒张晚期波运动速度变化差异无显著性意义,仅有下壁基底段和中间段运动速度升高(F=3.903、4.862,P＜0.05).③Ve/Va:在左心室下壁、前间隔和后壁的基底段,下壁和后间隔的中间段减低,差异有显著性意义(F=3.371～9.485,P＜0.05或P＜0.01).结论 本试验显示中长期模拟失重状态能引起人体左心室舒张功能下降,主要表现为左心室壁心肌舒张早期弛张性受损.     

双源CT在主动脉瓣置换术后机械瓣评估中的应用价值

目的 探讨双源CT(DSCT)三维心脏血管成像(CTA)对主动脉瓣置换术后机械瓣评估的临床应用价值.方法 34例主动脉瓣置换术后患者,19例为On-x瓣,15例为St jude瓣,34例均行DSCT检查,其中30例行1.5 T MR检查.两种瓣膜间进行对比,2组间图像质量的差异采用两独立样本Wilcoxon秩和检验进行分析.2组间两瓣叶开放关闭角度比较采用两独立样本t检验.CT与MRI的左心功能相关指标采用配对t检验进行分析.结果 34例患者680个期相中有391个期相为1级图像,171个期相为2级图像,118个期相为3级图像.On-x瓣组和St jude瓣组患者的图像质量差异无统计学意义(图像质量1～3级的Z值分别为-1.084、-0.088、-1.045,P值均>0.05).34例患者两瓣叶的平均开放角度82.0°±4.4°,平均关闭角度34.5°±5.7°,平均跨瓣弧度47.5°±7.5°.St jude瓣组跨瓣弧度(55.0°±1.8°)明显大于On-x瓣组(41.5°±4.1°),差异有统计学意义(t=-11.732,P=0.000).DSCT所测得左心室心功能指标与1.5 T MR差异均无统计学意义:射血分数(EF)[MR-EF(57.2 ±2.8)%,CT-EF(57.9±2.8)%,t=-0.496,P=0.623]、左心室舒张末期容积(EDV)[MR-EDV(121.6±9.1)ml,CT-EDV(132.9±11.2)ml,t=-1.198,P=0.240]、收缩期末期容积(ESV)[MR-ESV(55.1±6.9)ml,CT-ESV(59.5±7.6)ml,t=-1.094,P=0.283]、左心室舒张末心肌重量(Myo.mass)[MR-Myo.mass(155.5±12.6)g,CT-Myo.mass(147.9±11.6)g,t=1.823,P=0.079]及心输出量(CO)[MR-CO(5.7±0.4)ml/min,CT-CO(5.9±0.5)ml/min,t=-3.211,P:O.775].结论 三维心脏CTA是评估主动脉瓣置换术后机械瓣有效的无创性检查方法,借助DSCT与相关后处理软件可评估机械瓣的功能,测量机械瓣各瓣叶的开放及关闭角度,并支持左心室功能分析.     

儿童肥厚型心肌病磁共振延迟强化特征分析

目的分析肥厚型心肌病（HCM）患儿心脏受累心肌MRI对比剂延迟强化发生率及其与预后的相关性。方法收集2006年1月至2012年1月我院收治的HCM患儿71例,所有患儿均接受心脏MRI检查,并行对比剂增强心肌显像。根据左心室心肌是否存在延迟强化,将患儿分为延迟强化组和非延迟强化组,并进一步分析受累心肌对比剂延迟强化的范围及程度等。应用Kaplan-Meier生存曲线分析两组患儿的预后差别,两组临床数据间的统计分析采用t检验。结果71例HCM患儿中,9例（12.7%）患儿左心室为对称性肥厚,其中2例患儿进展至终末期。52例（73%）患儿出现心肌延迟强化,其延迟强化组患儿左心室质量高于非延迟强化组患儿[（112.7±57.9）g/m2 vs.（70.3±37.4）g/m2],两组间差异有统计学意义（t=2.71,P=0.025）;但两组左室室壁厚度[（19.4±6.3）mm/m2 vs.（18.1±7.9）mm/m2]比较,差异无统计学意义（t=0.69,P=0.513）。HCM患儿随访（2.4±1.6）年显示,心肌延迟强化与不良心血管事件的发生密切相关（χ2=4.77,P=0.029）。结论HCM患儿中,其心肌延迟强化发生率与成人患者接近,并且心肌延迟强化具有判断患儿预后的临床价值。     

法布里病累及心脏的临床及MR特征分析

目的探讨法布里病(AFD)累及心脏的临床及心脏MR(CMR)特征。方法回顾性纳入2018年1月至2021年3月阜外医院经基因检测或病理确诊的AFD患者8例(AFD组),其中男3例、女5例,年龄26~60(50±11)岁;同时纳入性别、年龄匹配的肥厚型心肌病(HCM)患者16例(HCM组)和健康对照者16名(正常组)作为对照,HCM组中男6例、女10例,年龄27~68(46±15)岁,正常组中男6名、女10名,年龄26~59(51±11)岁。收集患者的临床基线资料及CMR图像。采用CVI42软件分析CMR图像,并自动生成相应的参数。采用单因素方差分析或Kruskal-Wallis检验比较3组间参数值的差异,两组间比较采用独立样本t检验、Fisher确切概率法或Mann-Whitney U检验。结果AFD组临床和心电图表现与HCM组相比,除合并肾功能不全差异有统计学意义外,余表现差异均无统计学意义(P均>0.05)。AFD组的CMR显示5例为对称性或大致对称性增厚,3例为非对称性增厚;钆对比剂延迟强化(LGE)示5例患者出现心肌强化,以多发、肌壁间强化为主,部分呈局部、心内膜下强化。HCM组的CMR显示14例患者以非对称性室间隔增厚为主、伴或不伴左心室壁其他部位的增厚,2例表现为左心室中远部的增厚;LGE示14例患者出现心肌强化,表现为肥厚心肌内局灶性或斑片状强化,以室间隔右心室插入部局灶性强化多见,部分表现为左心室中远段心内膜下强化。AFD组、HCM组和正常组3组间比较显示,左心房前后径和左心室最大室壁厚度、左心室心肌质量指数(LVMI)、初始T1值组间差异具有统计学意义(P均<0.001),但左心房前后径和左心室最大室壁厚度在AFD组和HCM组间差异无统计学意义(P>0.05)。AFD组的LVMI较正常组和HCM组均增加(P<0.05)。T₁ mapping示AFD组的初始T1值[(1177.4±46.0)ms]显著低于正常组[(1244.5±34.3)ms]和HCM组[(1278.8±41.6)ms],差异具有统计学意义(F=13.10,P<0.001)。结论AFD与HCM的临床表现相似,当临床怀疑AFD时,影像学检查应首选CMR检查,特别是T1 mapping技术可以为AFD的诊断提供重要价值。     

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.     

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.     

Comparison of T2-weighted spin-echo and fast spin-echo techniques in the evaluation of myelination

To evaluate T2-weighted fast spin-echo (FSE) and conventional spin-echo (CSE) magnetic resonance (MR) techniques in the assessment of brain myelination, 100 consecutive pediatric patients were imaged prospectively with both CSE and FSE sequences. All patients underwent a routine MR examination that included T2-weighted CSE imaging (imaging time, 10 minutes 21 seconds) and T2-weighted FSE imaging (imaging time, 2 minutes 5 seconds). The two techniques were compared for estimating the degree of myelination (using normal anatomic landmarks) by blind review. With T2-weighted CSE images as the “gold standard” for estimation of normal myelination, FSE images were evaluated to determine if they showed the degree of myelination similarly to CSE images. There was a strong correlation (P <.01) between CSE and FSE images in the estimation of myelination over a wide range of patient ages.     

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.