质子磁共振波谱和MR表观扩散系数在短暂性脑缺血发作中的应用

目的:利用质子磁共振波谱(1H-MRS)技术和MR表观扩散系数(ADC)分析短暂性脑缺血发作(TIA)的脑代谢改变.方法:应用多体素1H-MRS技术和弥散加权成像分别对30例TIA患者和30例正常志愿者进行检查,测量双侧大脑半球半卵圆中心ADC值和脑内代谢物氮-乙酰天门冬氨酸(NAA)、胆碱(Cho)、肌酸(Cr)和乳酸(Lac)的峰高比率,并作统计学分析.结果:30例病例中有11例患侧ADC值(6.31±0.87×10-4mm2/s)较对侧(7.97±0.79×10-4mm2/s)及正常对照组(8.46±0.79×10-4mm2/s)显著下降, 有统计学意义差异(P＜0.01).病变侧半卵园中心NAA/Cho(1.45±0.29)、NAA/Cr(1.56±0.23)低于对侧(1.65±0.21,1.81±0.16)及正常对照组(1.62±0.18,1.80±0.12),差异有显著性意义(P＜0.01);Cho/Cr(1.20±0.16)高于对侧(1.07±0.15)及正常对照组(1.05±0.11),差异有显著性意义(P＜0.05);Lac/NAA(0.18±0.06)高于对侧(0.00±0.00)及正常对照组(0.00±0.00), 差异有显著性意义(P＜0.01). 结论:多体素1H-MRS技术可以定量反映TIA患者脑组织神经细胞的生物代谢改变,其准确性及敏感性优于ADC值,1H-MRS技术结合弥散加权成像,为TIA的诊断提供了客观的影像学依据.     

阻塞性睡眠呼吸暂停综合征的质子磁共振波谱研究

目的:探讨阻塞性睡眠呼吸暂停综合征(OSAS)的质子磁共振波谱(1H-MRS)改变及其临床应用价值.方法:分别对33例OSAS患者和20例健康志愿者行1H-MRS,经多导睡眠仪监测将患者分为轻度OSAS(16例)和中重度OSAS(17例),分别测量脑灰质和脑白质的代谢物包括氮-乙酰天门冬氨酸(NAA)、胆碱(Cho)、肌酸(Cr)和乳酸(Lac)的波峰下面积,计算NAA/Cho、NAA/Cr、Cho/Cr,对组间代谢物比值的差异进行统计学分析.结果:中重度OSAS患者白质区NAA/Cho(1.56±0.21)低于轻度OSAS患者(1.88±0.23)及正常对照组(1.89±0.25),差异有显著性意义(P<0.01),NAA/Cr轻度降低,Cho/Cr轻度升高,但与轻度OSAS患者和正常对照组比较,无统计学意义(P>0.05).轻度OSAS患者灰、白质NAA/Cho、NAA/Cr、Cho/Cr 与正常对照组之间差异均无显著性意义(P>0.05).结论:1H-MRS能够早期发现OSAS患者的脑代谢异常,对临床诊断和治疗具有重要价值.     

短暂性脑缺血发作与脑梗死的1H-MRS比较研究

目的比较短暂性脑缺血发作（TIA）和脑梗死的氢质子磁共振波谱（1^H-MRS）改变,探讨1^H-MRS在TIA中的应用价值。资料与方法对30例TIA和24例脑梗死患者行1^H-MRS检查,同期选择24名健康志愿者作为对照。分别比较TIA患者病变侧和对侧半卵圆中心、脑梗死患者梗死灶与对侧正常脑组织代谢物氮-乙酰天门冬氨酸（NAA）、胆碱（Cho）和肌酸（Cr）含量的差异,并观察有无乳酸（Lac）峰出现,再对TIA患者、脑梗死患者及正常对照组之间脑内NAA、Cho、Cr和Lac含量的差异进行比较。结果TIA患者病变侧半卵圆中心NAA降低、Cho升高,与对侧相应区域以及正常对照组比较差异均有统计学意义（P〈0.01）,而两侧Cr含量差异无统计学意义（P〉0.05）,脑梗死患者梗死灶内NAA、Cho和Cr与对侧正常脑组织和正常对照组比较均有下降,差异有统计学意义（P〈0.01）,但TIA患者NAA下降幅度明显小于脑梗死患者,差异有统计学意义（P〈0.01）;10例TIA患者、23例脑梗死患者于病侧发现Lac峰,TIA的Lac含量低于脑梗死,差异有统计学意义（P〈0.01）。结论TIA患者缺血脑组织存在代谢异常,但较脑梗死轻微,1^H-MRS能够早期发现这种异常,对TIA的早期诊断和治疗具有重要价值。     

阻塞性睡眠呼吸暂停低通气综合征的多体素~1H-MRS研究

目的探讨多体素质子磁共振波谱(1H-MRS)在阻塞性睡眠呼吸暂停低通气综合征(OSAHS)中的临床应用价值。材料与方法分别对20例临床诊断为中重度OSAHS病人(病变组)及年龄、性别相匹配的20名健康志愿者(对照组)行头颅多体素1H-MRS检查,记录两组半卵圆中心区、基底节区各代谢物比值,比较两组间的差异,观察有无乳酸(Lac)峰出现。记录病人相关临床指标,包括:睡眠呼吸暂停和低通气指数(AHI)和夜间平均血氧饱和度(SpO2),并与各代谢物比值进行相关性分析。结果病变组半卵圆中心区NAA/Cr、NAA/Cho低于对照组,Cho/Cr高于对照组,差异有统计学意义(P0.05)。基底节区NAA/Cr、NAA/Cho较对照组稍降低,Cho/Cr较对照组稍升高,差异无统计学意义(P0.05)。两组均未检测到Lac峰。AHI与半卵圆中心区NAA/Cho呈负相关(P0.05),SpO2与NAA/Cho呈正相关(P0.05),而AHI和SpO2与NAA/Cr、Cho/Cr无相关性(P0.05)。结论多体素1H-MRI能够早期发现OSAHS脑代谢改变,为临床诊治提供客观的影像学依据。     

急性CO中毒与正常人海马体1HMRS对照研究

目的:采用氢质子磁共振波谱成像(1 H-MRS)测量急性一氧化碳中毒(ACOP)患者与正常人海马区代谢物浓度(氮-乙酰天门冬氨酸NAA、胆碱Cho和肌酸Cr)并比较两组的差异.方法:所有受试者分为两组,ACOP组56例,平均年龄(48.9±10.9)岁;对照组27例,平均年龄(49.2±12.5)岁.所有病例均行两侧海马区MRS检查,记录两侧海马区NAA/Cr、Cho/Cr值,采用两个独立样本t检验比较对照组及ACOP组海马体部代谢物比值的差异.结果:ACOP组NAA/Cr值为1.014±0.683,对照组NAA/Cr值为1.697±0.711,差异有统计学意义(P=0.000).ACOP组Cho/Cr值为1.181±0.389,对照组Cho/Cr值为1.148±0.367,差异无统计学意义(P=0.602).结论:采用1 H-MRS可以准确反映ACOP患者海马区代谢物差异,为评估病情的严重性与早期诊断提供影像学支持.     

颅内结核瘤的质子MR波谱研究

目的探讨质子MR波谱(1H-MRS)对颅内结核瘤的诊断价值。资料与方法回顾性分析26例颅内结核瘤患者术前或接受治疗前的1H-MRS表现,1H-MRS采用多体素2D1H-MRS,点分辨表面线圈法(PRESS)。比较结核瘤病灶实质和对侧正常脑组织的胆碱(Cho)、肌酸(Cr)、N-乙酰天门冬氨酸(NAA)、Cho/Cr,Cho/NAA、NAA/Cho差异有无统计学意义,观察有无脂质(Lip)峰或氨基酸峰(AAs)出现。结果颅内结核瘤实质部分Cho较对侧升高,差异无统计学意义(颅内结核瘤和对侧正常脑组织Cho分别为366.7±137.4,325.4±126.4,P>0.05),Cr、NAA、NAA/Cho低于对侧,差异有统计学意义(颅内结核瘤和对侧正常脑组织Cr分别为163.6±74.1,300.1±140.5,P<0.01;NAA分别为239.4±96.6,475.3±244.7,P<0.01;NAA/Cho分别为0.74±0.35,1.56±0.60,P<0.01),Cho/Cr、Cho/NAA高于对侧,差异有统计学意义(颅内结核瘤和对侧正常脑组织Cho/Cr分别为2.05±0.63,1.14±0.38,P<0...     

MR动脉血质子自旋标记与波谱成像在颈内动脉系统狭窄或闭塞的应用研究

目的 探讨MR动脉血质子自旋标记(ASL)与氢质子磁共振波谱成像(1H-MRS)在颈动脉系统狭窄或闭塞的应用价值. 资料与方法 28例单侧颈内动脉(ICA)/大脑中动脉(MCA)重度狭窄或闭塞患者行ASL 和1H-MRS检查.对ASL后处理的相对脑血流量(CBF) 图进行定性和定量分析;对1H-MRS测量病变侧和对侧脑组织的氮-乙酰天门冬氨酸(NAA)、胆碱(Cho)、肌酸(Cr)的波峰下面积,比较两侧各代谢物峰下面积比值(NAA/Cho、NAA/Cr、Cho/Cr)的差异,并观察是否出现乳酸(Lac)峰. 结果 28例CBF图显示18例病变侧灌注较对侧降低,10例未见明显异常;1H-MRS显示病变侧的NAA/Cho、NAA/Cr低于对侧,差异有统计学意义(P<0.01),Cho/Cr高于对侧,差异有统计学意义(P<0.01),3例于病变侧检测到Lac峰. 结论 ASL 能够早期发现颈动脉系统狭窄或闭塞患者的CBF改变,1H-MRS能够显示缺血脑组织的代谢异常.     

1H-MRS in peritumoral region of glioblastoma

目的:评价2D多体素磁共振氢质子波谱成像技术(1H-MRS)在胶质母细胞瘤周围区中的应用价值.方法:对30例胶质母细胞瘤患者行常规MRI及1H-MRS检查,所有患者均行增强扫描.测量肿瘤周围区(包括水肿区及瘤周显示正常区域)的Cho/Cr、Cho/NAA、NAA/Cr的比值,并且计算瘤周显示正常区域的NAA/nCr的比值,将以上值与对侧正常区域的相应比值进行两样本配时t检验,分析其差异是否有统计学意义.结果:肿瘤周围水肿区及瘤周显示正常区的Cho/Cr、Cho/NAA的比值较对侧明显升高,差异有统计学意义(P<0.05).肿瘤周围水肿区的NAA/Cr值较对侧降低且差异有统计学意义(P<0.05);肿瘤周围显示正常区的NAA/Cr值较对侧亦有降低,但差异无统计学意义(P> 0.05),瘤周显示正常区NAA/nCr值较对侧明显降低,差异有统计学意义(P<0.05).结论:2D多体素1H-MRS成像技术对肿瘤周围区代谢物变化的检测可为推断胶质母细胞瘤瘤周区肿瘤细胞的浸润范围提供依据.     

阻塞性睡眠呼吸暂停低通气综合征的多体素^1H-MRS研究

目的探讨多体素质子磁共振波谱（1H-MRS）在阻塞性睡眠呼吸暂停低通气综合征（OSAHS）中的临床应用价值。材料与方法分别对20例临床诊断为中重度OSAHS病人（病变组）及年龄、性别相匹配的20名健康志愿者（对照组）行头颅多体素1H-MRS检查,记录两组半卵圆中心区、基底节区各代谢物比值,比较两组间的差异,观察有无乳酸（Lac）峰出现。记录病人相关临床指标,包括：睡眠呼吸暂停和低通气指数（AHI）和夜间平均血氧饱和度（SpO2）,并与各代谢物比值进行相关性分析。结果病变组半卵圆中心区NAA/Cr、NAA/Cho低于对照组,Cho/Cr高于对照组,差异有统计学意义（P〈0.05）。基底节区NAA/Cr、NAA/Cho较对照组稍降低,Cho/Cr较对照组稍升高,差异无统计学意义（P〉0.05）。两组均未检测到Lac峰。AHI与半卵圆中心区NAA/Cho呈负相关（P〈0.05）,SpO2与NAA/Cho呈正相关（P〈0.05）,而AHI和SpO2与NAA/Cr、Cho/Cr无相关性（P〉0.05）。结论多体素1H-MRI能够早期发现OSAHS脑代谢改变,为临床诊治提供客观的影像学依据。     

帕金森病中脑黑质3D多体素~1H-MRS研究

目的探讨1H-MRS检测帕金森病(Parkinson's disease,PD)黑质神经元代谢产物变化的意义。方法 PD患者30例,正常对照组20例。采用3.0T MRI对PD患者及正常对照者黑质进行3D多体素1H-MRS检测,获得代谢物间相对比值,NAA/Cr、NAA/Cho、NAA/(Cho+Cr)。然后,对PD组与正常对照组黑质代谢产物进行比较;对非对称PD患者两侧黑质代谢产物进行比较;对不同病情程度的PD的黑质代谢产物进行比较。结果 1)PD组与对照组黑质NAA/Cr、NAA/Cho、NAA/(Cho+Cr)相对比差异有显著性(P0.05);2)PD组患肢对侧与患肢同侧黑质NAA/Cr、NAA/Cho、NAA/(Cho+Cr)相对比差异有显著性(P0.05);3)H-Y分级较轻组与较重组组间黑质NAA/Cr、NAA/Cho、NAA/(Cho+Cr)相对比差异有显著性(P0.05)。结论 PD患者黑质代谢产物有变化,非对称性PD患者两侧黑质代谢产物含量不同,病情较轻组与较重组黑质代谢产物有差异,1H-MRS检测黑质代谢产物含量对PD早期诊断具有重要作用。     

Cardiovascular catheters and accessories: Ex vivo testing of ferromagnetism,heating, and artifacts associated with MRI

The purpose of this study was to evaluate the MR safety of cardiovascular catheters and accessories. Intravascular cardiovascular catheters and accessories were tested for MR safety at 1.5 T using previously described techniques with respect to the evaluation of magnetic field attraction (deflection angle method), heating (temperature measured immediately before and after performing MRI), and artifacts (using a fast spoiled gradient-recalled acquisition in steady state [GRASS] pulse sequence). Two devices were attracted (RV pacing lead and Oximetrix 3 SO₂ optical module) by the static magnetic field. Each of the other objects displayed no attraction. Heating was +0.2°C for the sample cardiovascular catheter tested (Opticath). Artifacts varied from moderate to severe, depending on the amount and type of metal present in the device. Despite these ex vivo test results, further safety consideration should be given to the cardiovascular devices that have a conductive wire component (ie, certain types of the cardiovascular catheters) because of the potential for inducing current and excessive heating in these devices during MRI, especially using a high-field-strength MR system. The cardiovascular catheters evaluated in this study or those with a similar design are not recommended for use in patients undergoing MRI procedures.     

Interactive multiplanar reformation of conventional two-dimensional MR images

In this report, we describe a new application for three-dimensional computer image processing that can provide for improved depiction of anatomical structures on routine nonvolumetric magnetic resonance (MR) examinations. The technique can be applied to standard two-dimensional MR images of the brain, spine, musculoskeletal system, and body including those obtained with relatively thick slices and with an intersection gap. This report demonstrates use of the reformation technique to establish retrospectively the symmetry in bilateral structures that were displayed out of alignment due to suboptimal patient positioning or patient motion during image acquisition and to improve the depiction of anatomical structures that were oriented out of the plane of original image acquisition. This method can be performed interactively in near real time, requires no increase in patient examination time, and has potential application throughout the body.     

Analysis of magnetization transfer effects on T1-weighted spin-echo scans using a simple tissue phantom simulating gadolinium-enhanced brain lesions

The purpose of this study was to analyze the effect of several magnetization transfer (MT) pulse and T1-weighted spin-echo (SE) sequence parameters on lesion-to-background contrast, using a simple tissue phantom emulating the T1 relaxation and MT properties of gadolinium-enhanced brain lesions. Eggbeaters (Nabisco Inc., East Hanover, NJ) liquid egg product was doped with gadolinium in six concentrations from .0 to 1.0 mmol and cooked. The gadolinium-doped egg phantom and normal volunteer brains were studied using an SE sequence with TE = 20 msec and high power, pulsed, off-resonance MT saturation. The effects of MT pulse frequency offset (1,000–6,000 Hz), sequence repetition time (TR = 500–1,000 msec, with MT power held constant), and slice-select flip angle (60–120 degrees) on the magnetization transfer ratio (MTR) and the simulated lesion-to-background contrast were determined at the different “Intralesion” gadolinium concentrations. The MTR and lesion-to-background contrast of all materials were greatest at narrow MT pulse frequency offsets. There was an inverse relationship between gadolinium concentration and MTR and a positive correlation between the gadolinium concentration and lesion-to-background (L/B) contrast, a weak negative correlation between slice-select flip angle and L/B, and a negative correlation between TR and L/B. The relaxation properties and MT behavior of the egg phantom are close to that expected for enhancing brain lesions, allowing a rigorous analysis of several variables affecting lesion-to-background contrast for high MT power, T1-weighted SE sequences.     

Bilateral thalamic glioma: case report

We report a 63-year-old man who had a rare bilateral thalamic glioma. He complained of difficulty with calculations and had mental deterioration. T1-weighted images revealed bilateral thalamic swelling with homogeneous low signal and no contrast enhancement. The tumour, showing decrease of N-acetylaspartate and the presence of lactate on magnetic resonance spectroscopy, was diagnosed as an astrocytoma by stereotactic biopsy. Received: 27 August 1999/Accepted: 7 January 2000     

Diffusion- and perfusion-weighted MRI in a patient with a prolonged reversible ischaemic neurological deficit

We report acute and follow-up diffusion- and perfusion-weighted MRI (DWI, PWI) findings in a patient with a prolonged reversible ischaemic neurological deficit. PWI 12 h after the patient was last seen to be without symptoms revealed a large perfusion deficit in the left posterior MCA territory with a relatively inconspicuous and much smaller abnormality on DWI. Follow-up showed resolution of abnormalities on both DWI and PWI, and conventional MRI was normal, apart from a very slight abnormality, visible only on FLAIR images, at the centre of the initially DWI-positive region. These findings demonstrate the utility of PWI when be used in combination with DWI to investigate the pathophysiology of transient ischemic syndromes. Received: 26 July 1999/Accepted: 20 September 1999     

青年抑郁症患者基底节和丘脑3D ^1H-MRS研究

目的：探讨青年抑郁症患者基底节和丘脑可能存在的神经生化异常。方法：对44例青年抑郁症患者（抑郁症组）和40例年龄和性别匹配的健康志愿者（对照组）进行常规MRI扫描和三维氢质子MR波谱（3D -1H-MRS）检查，测量双侧基底节和丘脑的N-乙酰天门冬氨酸（NAA）、胆碱复合物（Cho）、肌醇（mI）和肌酸（Cr）的绝对值，并计算它们与Cr的比值。对两组实验对象各代谢物及其比值进行统计学分析。结果：①抑郁症组双侧豆状核和尾状核头部Cho/Cr、mI/Cr明显高于对照组，差异有显著性意义（P〈0.05），而NAA/Cr在两组间差异无统计学意义（P〉0.05）；②抑郁症组丘脑NAA/Cr、Cho/Cr和mI/Cr与对照组相比，差异无统计学意义（P〉0.05）。结论：青年抑郁症患者基底节区豆状核和尾状核头部的Cho/Cr、mI/Cr增高，可能构成该病的神经生物学基础。     

大脑胶质瘤病磁共振成像结合磁共振波谱成像的诊断价值

目的：探讨磁共振成像（MRI）结合磁共振波谱成像（MRS）对大脑胶质瘤病的诊断价值。方法对15例经活体组织检查或手术病理证实的大脑胶质瘤病患者的临床表现及MRI平扫、增强,MRS影像学资料进行回顾性分析。MRI常规行T1WI、T2WI及FLAIR序列,采用时间飞跃法（TOF）的磁共振血管成像（MRA）,T1WI增强扫描。氢质子MRS采用单体素STEAM序列,并分析N-乙酰天门冬氨酸（NAA）、肌酸（Cr）、胆碱复合物（Cho）等物质峰值改变。结果所有病例均侵犯2个或2个以上脑叶,以颞叶、枕叶、胼胝体、基底节和丘脑等部位侵犯受累常见。病变区T1WI呈低或等低信号、T2WI呈高或混杂高信号、FLAIR上为高信号,未见明显坏死、钙化,受累区域脑组织肿胀,占位效应轻。注射钆喷酸葡胺增强扫描示10例无明显强化、3例斑片状强化、1例结节状强化、1例线状轻度强化。病变区域MRS表现为不同程度NAA降低,NAA/Cr比值降低;Cho上升,Cho/Cr和Cho/NAA的比值上升。结论 MRI结合MRS对大脑胶质瘤病的诊断及鉴别诊断具有临床价值,是目前诊断大脑胶质瘤病的首选影像学方法。     

Contrast-to-noise ratio in functional MRI of relative cerebral blood volume with sprodiamide injection

The purpose of this study was to investigate the dependence of contrast-to-noise ratio (CNR) on the dose and rate of sprodiamide injection in magnetic resonance relative cerebral blood volume (rCBV) imaging. rCBV maps for 35 normal volunteers were constructed from dynamic MR image sets acquired with echo-planar spin-echo imaging after intravenous injection of sprodiamide. Doses of .1, .2, and .3 mmol/kg, at rates of 2 ml/second and 5 ml/second, were tested. CNRs and blood/volume ratios of gray to white matter were computed. CNR depended on dose (P < .0001) but was independent of injection rate (P < .69). rCBV ratios of gray to white matter were dose independent (P < .38) and rate independent (P < .97). The dependence of CNR on dose, but not injection rate, has practical implications in optimal protocol design. The independence of gray/white ratios supports the theory underlying the generation of rCBV maps.