动态增强MR灌注成像在脑胶质瘤诊断中的价值

目的　探讨动态增强T2 WMR灌注成像在脑胶质瘤术前分级预测及鉴别诊断中的价值。资料与方法　有病理或追踪结果的 4 8例脑病变患者 ,其中胶质瘤 2 5例 (高、低级别胶质瘤分别为 16例和 9例 ) ,非胶质瘤病变 2 3例。全部病例均行常规T1WI、T2 WI和EPI SE序列动态增强MR灌注成像。计算每个病灶的最大相对脑血容量 (rCBV)比值 (病灶最大rCBV/对侧正常脑白质rCBV)。分析胶质瘤的最大rCBV比值与其组织学级别的关系 ,并比较胶质瘤与非胶质瘤的灌注异常及常规MRI强化表现。结果　高级别胶质瘤 ( 16例 )的最大rCBV比值为4 .6 0± 1.98( 2 .5 5～ 9.2 2 ) ,低级别胶质瘤 ( 9例 )的最大rCBV比值为 1.86± 1.5 2 ( 0 .85～ 5 .72 ) ,经t检验 ,两组之间有显著统计学差异 (P <0 .0 1)。脑膜瘤、转移瘤、血管母细胞瘤、淋巴瘤均显示有局部高灌注 ,最大rCBV比值为5 .35± 2 .39( 3.15～ 12 .39) ,而有强化表现的脑梗死、脑炎性灶及放射性脑损伤表现为低、等灌注 ,最大rCBV比值为1.2 7± 0 .36 ( 0 .85～ 1.72 )。结论　MR灌注成像在胶质瘤的术前影像学分级预测上有重要价值 ,在脑胶质瘤的某些鉴别诊断上亦具有一定的参考价值     

MR灌注成像在鉴别单发脑转移瘤与高级别胶质瘤中的价值

目的探讨MR灌注成像在鉴别单发脑转移瘤与高级别胶质瘤中的作用及价值。方法对10例单发脑转移瘤和15例高级别胶质瘤患者行手术前MR灌注成像扫描。分析其MR灌注曲线及伪彩图像,测量肿瘤实质部分及瘤周水肿区最大相对脑血容积(rCBV)值及相应部位相对平均通过时间(rMTT)数值并将所测值进行t检验。结果单发脑转移瘤的MR灌注曲线形态和伪彩图像中的色彩特点与高级别胶质瘤有明显区别。单发脑转移瘤与高级别胶质瘤肿瘤实质部分的最大rCBV值分别为3.70±2.34、6.01±2.17,瘤周水肿区则分别为0.80±0.28、1.77±1.19。单发脑转移瘤与高级别胶质瘤肿瘤实质相应部位的rMTT值分别为1.17±0.39、1.11±0.18,瘤周水肿区则分别为1.17±0.38、1.02±0.20。两者肿瘤实质部分和瘤周水肿区的rCBV值均数之间差异有统计学意义(P<0.05),而相应的rMTT值均数之间差异没有统计学意义(P>0.05)。结论MR灌注成像对术前鉴别单发脑转移瘤与高级别胶质瘤有临床实用价值。     

MR扩散、灌注成像在脑胶质瘤分级中的价值

目的评价MR扩散、灌注成像在脑胶质瘤病理分级诊断中的价值.资料与方法对经组织病理学证实的28例脑胶质瘤患者(19例高级别胶质瘤,9例低级别胶质瘤),术前行常规MR平扫,MR扩散成像、灌注成像和常规增强扫描,重建出表观扩散系数(ADC)彩图和相对脑血流容量(rCBV)彩图后,分别测量出肿瘤实质部分的最小ADC值和最大rCBV值.用两样本t检验分析肿瘤的ADC值、rCBV值与术后病理学分级间的关系,用线性回归分析ADC值与rCBV值间的关系.结果 19例高级别胶质瘤的平均最小ADC值为(0.95±0.29)×10-3 mm2/s;9例低级别胶质瘤的平均最小ADC值为(1.37±0.16)×10-3 mm2/s,两组间ADC值有统计学显著性差异(t=4.09,P<0.001).高级别胶质瘤的平均最大rCBV值为5.49±1.87;低级别胶质瘤的平均最大rCBV值为1.70±0.73,两组间rCBV值有统计学显著性差异(t=5.89,P<0.001).此外,ADC值与rCBV值间有统计学显著负线性相关性(r＝-0.51,P<0.05).结论 MR扩散、灌注成像能提供常规MRI所不能获取的诊断信息,更低的ADC值和更高的rCBV值提示为高级别胶质瘤;更高的ADC值和更低的rCBV值提示为低级别胶质瘤,它们对脑胶质瘤的术前分级诊断具有重要价值.     

颅内原发性淋巴瘤DSC灌注成像的初步研究

目的探讨颅内原发性淋巴瘤动态对比磁敏感增强(DSC)灌注成像的特点。资料与方法采用平面回波(EPI)序列对9例颅内原发性淋巴瘤患者术前行DSC灌注成像,获得相对脑血容量(rCBV)图、相对脑血流量(rCBF)图、平均通过时间(MTT)图和时间-信号曲线,并计算肿瘤实质最大rCBV比值和MTT比值,结合病理特征与14例高级别(Ⅲ、Ⅳ级)星形细胞瘤作对照。结果颅内原发淋巴瘤肿瘤实质最大rCBV比值为1.71±0.59,而高级别星形细胞瘤肿瘤实质最大rCBV比值为5.17±1.73,两者差异有统计学意义(P<0.001),但两组病例肿瘤实质MTT比值间的差异无统计学意义(P=0.101)。颅内原发性淋巴瘤肿瘤实质时间-信号曲线首过期后曲线超过基线水平,高级别星形细胞瘤肿瘤实质时间-信号曲线回复基线前可出现一个小的再下降波形,且首过期后曲线均未超过基线水平。颅内原发性淋巴瘤瘤细胞密集,核大浓染,胞质少,可见瘤细胞围绕血管呈"袖套"状排列,肿瘤血管内皮增生少见。高级别星形细胞瘤可见大量肿瘤血管。结论颅内原发淋巴瘤DSC灌注成像呈相对低灌注,肿瘤实质最大rCBV比值低于高级别星形细胞瘤,且时间-信号曲线有别于高级别星形细胞瘤,是由两者不同的病理学基础决定,DSC灌注成像有助于提高颅内原发性淋巴瘤的MRI诊断能力。     

中枢神经系统原发淋巴瘤和高级别星形细胞瘤MR灌注成像的对比研究

目的 探讨MR灌注成像鉴别中枢神经系统原发淋巴瘤(PCNSL)和高级别星形细胞瘤的价值.方法 PCNSL患者12例,高级别星形细胞肿瘤患者23例,手术前行常规MR检查及MR灌注检查,比较其MR灌注伪彩图像和灌注曲线,测量肿瘤实质部分最大相对脑血容量(rCBV),将所测量数值进行t检验.结果 PCNSL实质部分rCBV平均为1.8±0.5;高级别星形细胞瘤实质部分rCBV平均为3.9±0.9,二者之间差异有统计学意义(P<0.05).PCNSL实质区域时间-信号曲线对比剂首过后曲线逐渐接近基线,12例中有7例超过基线水平.高级别星形细胞瘤实质区域时间-信号曲线对比剂首过后曲线逐渐向基线水平靠拢,但均不能完全恢复到基线水平.结论 MR灌注成像有助于鉴别PCNSL和高级别星形细胞瘤.     

脑转移瘤动态增强磁化率MR灌注成像特点的研究

目的研究治疗前不同来源脑转移瘤的动态增强磁化率(DSC)MR 灌注成像特点。方法对28例经病理或随访证实为脑转移瘤的患者行手术前 DSC MR 灌注成像扫描。分析 MR 灌注曲线及伪彩图像,测量肿瘤实质部分及瘤周水肿区最大相对脑血容积(rCBV)值及相应部位相对平均通过时间(rMTT)数值,并将所测量数值进行 t 检验分析,P<0.05为差异具有统计意义。结果不同来源脑转移瘤的 MR 灌注曲线、伪彩图像特点无明显差异。脑转移瘤肿瘤实质部分灌注程度与正常脑灰质相仿,瘤周水肿区表现为低灌注,两者的灌注时间均延长。12例来源于肺癌与5例来源于乳腺癌的脑转移瘤肿瘤实质部分的最大 rCBV 值(分别为272.5±34.3和210.8±59.4)及相应部位的 rMTT 数值(分别为117.7±4.3和105.2±21.3)之间以及两者瘤周水肿区 rCBV 值(分别为122.0±16.3和68.4±6.1)和 rMTT 值(分别为112.7±8.3和139.8±37.9)之间差异均无统计学意义(P>0.05)。结论不同来源脑转移瘤的 MR 灌注成像特点趋于一致。     

3.0T动态磁敏感对比增强磁共振成像在鉴别脑胶质瘤复发与放射性脑损伤中的价值

目的 探讨3.0T 动态磁敏感对比增强磁共振灌注成像在鉴别脑胶质瘤术后复发与放射性脑损伤方面的应用价值.方法 41例脑胶质瘤术后放疗后患者,肿瘤复发组24例,放射性脑损伤组17例.使用3.0T MR扫描仪行静脉团注Gd-DTPA的DSC灌注检查,分析强化中心区及强化边缘区血流灌注指标:平均rCBVmax比值、平均rCBFmax比值与平均rMTTmax比值.结果 强化中心区域的平均rCBVmax及平均rCBFmax比值分别为5.279±1.588及4.876±1.436,放射性脑损伤组强化中心区域的平均rCBVmax及平均rCBFmax比值分别为2.244±0.698及2.051±0.992,两灌注指标在肿瘤复发和放射性脑损伤2组间差异均具有统计学意义.结论 平均rCBFmax比值与平均rCBVmax比值均可用于脑胶质瘤术后肿瘤复发与放射性脑损伤的鉴别.动态磁敏感对比增强磁共振成像有助于鉴别脑胶质瘤术后复发与放射性脑损伤.     

磁共振灌注加权成像在肝豆状核变性诊断中的应用

目的 探讨MR灌注加权成像(perfnsion weighted imaging,PWI)在肝豆状核变性(hepatolenticular degener-ation,HLD)诊断中的应用价值.资料与方法 对30例临床诊断为HLD的患者及对照组25例行常规颅脑MRI,以及注射对比剂(Gd-DTPA)后采用自旋回波-回波平面成像(SE-EPI)序列MR PWI检查.通过工作站重组相对局部脑血容量(rCBV)图、局部脑血流量(rCBF)图及对比剂平均通过时间(rMTT)图.计算每例受试者的豆状核及丘脑等HID患者脑病变易发区域的rCBV、rCBF及rMTT相对值,比较HLD患者组和对照组之间的rCBV、rCBF及rMTT相对值差别.结果 常规MRI异常信号(多为长T1、长T2信号)最常见于HLD患者的豆状核及丘脑等部位.PWI显示HLD患者组的rCBV、ICBF均值较对照组低.结论 MR脑血流灌注图和半定量分析有助于观察HLD患者病变区的血流动力学改变,与常规MRI结合可同时反映HID患者脑病变的部位、形态和功能变化.     

脑胶质瘤磁共振灌注成像与病理对照研究

目的　评价磁共振灌注成像在术前评估脑胶质瘤组织病理学分级中的价值。方法　经手术及病理证实的胶质瘤共 2 6例。行常规MR及MR灌注成像检查。构建脑血流容积 (CBV)图和脑血流量 (CBF)图 ,计算最大相对CBV(rCBV)和最大相对CBF(rCBF) ,并与组织病理学分级对照。结果　低级组 (Ⅰ～Ⅱ级 )胶质瘤rCBV、rCBF范围分别为 0 .72～ 4.2 6和 0 .82～ 2 .89,均值分别为 2 .10± 1.18和 1.5 2± 0 .65。高级组 (Ⅲ～Ⅳ级 )胶质瘤rCBV、rCBF范围分别为 0 .89～ 10 .0 2和 1.5 0～ 6.40 ,均值分别为 5 .2 3± 1.86和 4.81± 2 .60。 2组rCBV和rCBF差别有显著性 (t检验 ,Ρ <0 .0 1)。非参数相关性分析表明rCBV与rCBF间有显著的正相关性 (r =0 .712 ,Ρ <0 .0 1)。结论　脑磁共振灌注成像对胶质瘤的术前分级有重要临床意义。     

MR灌注成像在脑胶质瘤术前分级中的价值

目的 :运用磁共振灌注成像 (PWI)技术 ,探讨脑血流容量 (rCBV)及其rCBV比值在脑胶质瘤术前分级中的价值。方法 :3 2例经病理证实的脑胶质瘤 ,其中Ⅰ级 2例 ,Ⅱ级 9例 ,Ⅲ级 14例 ,Ⅳ级 7例 ,行PI扫描 ,计算肿瘤最大rCBV及其rCBV比值 ,将结果与病理分级进行对照。结果 :低分级胶质瘤rCBV值为 43 .82± 15 .5 1,rCBV比值为 2 .89± 0 .83 ;高分级胶质瘤rCBV值为 12 4.3 2± 3 0 .5 4,rCBV比值为 7.82± 1.2 1;两组的rCBV值以及rCBV比值差异均有显著性意义 (P <0 .0 0 1)。结论 :不同分级的胶质瘤之间的rCBV及rCBV比值差异存在显著性意义 ,PWI技术有助于脑胶质瘤的术前分级。     

Analysis of perfusion weighted image of CNS lymphoma

Purpose

It is difficult to differentiate CNS lymphoma from other tumors such as malignant gliomas, metastases, or meningiomas with conventional MR imaging, because the imaging findings are overlapped between these tumors. The purpose of this study is to investigate the perfusion weighted MR imaging findings of CNS lymphomas and to compare the relative cerebral blood volume ratios between CNS lymphomas and other tumors such as high grade gliomas, metastases, or meningiomas.

Materials and methods

We retrospectively reviewed MRI findings and clinical records in 13 patients with pathologically proven CNS lymphoma between January 2006 and November 2008. We evaluated the relative cerebral blood volume ratios of tumor, which were obtained by dividing the values obtained from the normal white matter on MRI.

Results

Total 13 patients (M:F = 8:5; age range 46-67 years, mean age 52.3 years) were included. The CNS lymphomas showed relatively low values of maximum relative CBV ratio in most patients regardless of primary or secondary CNS lymphoma.

Conclusion

Perfusion weighted image may be helpful in the diagnosis of CNS lymphoma in spite of primary or secondary or B cell or T cell.     

Perfusion magnetic resonance imaging and magnetic resonance spectroscopy of cerebral gliomas showing imperceptible contrast enhancement on conventional magnetic resonance imaging

The purpose of the present paper was to evaluate the utility of perfusion MRI in cerebral gliomas showing imperceptible contrast enhancement on conventional MRI, and to evaluate the relationships of perfusion MRI and magnetic resonance (MR) spectroscopic results in these tumours. Twenty-two patients with histopathologically proven cerebral gliomas and showing insignificant contrast enhancement on conventional MR were included in the present study. All patients underwent perfusion MRI and MR spectroscopy on a 1.5-T MR system. Significant differences of the relative cerebral blood volume (rCBV) values and the choline : creatine ratios were noted between low-grade and anaplastic gliomas (P < 0.01). Good correlation was found between the rCBV values and the choline : creatine values (y = 0. 532x + 1.5643; r = 0.67). Perfusion MRI can be a useful tool in assessing the histopathological grade of non-contrast-enhancing cerebral gliomas. Along with MR spectroscopic imaging it can serve as an important technique for preoperative characterization of such gliomas, so that accurate targeting by stereotactic biopsies is possible.     

Primary central nervous system immunocytoma: MRI and spectroscopy

We report on a young woman with a primary cerebral immunocytoma. Most primary cerebral nervous system lymphomas (PCNSL) are highly malignant undifferentiated B-cell tumours, there are few data on the clinical course, MRI and spectroscopy findings of this rare PCNSL subtype. MRI revealed a radially enhancing tumour with mild perifocal oedema. MR spectroscopy indicated low cell turnover. Slow clinical progression, no significant changes with treatment, and imaging findings were consistent with a low-grade malignant tumour. Received: 21 January 2000/Accepted: 15 February 2000     

Cerebral perfusion MRI with arterial spin labeling technique at 0.5 Tesla

PURPOSE: Our aim was to evaluate the feasibility of cerebral perfusion MRI using an arterial spin labeling technique at 0.5 T. METHOD: We performed perfusion imaging with a flow-sensitive alternating inversion recovery (FAIR) sequence in a total of 37 patients with cerebral infarction. RESULTS: FAIR perfusion images demonstrated areas of pathological perfusion corresponding (13 patients) or not corresponding (15 patients) to the infarcted area on MR images. Among 19 patients in whom comparison between FAIR perfusion imaging and regional cerebral blood flow single photon emission CT was available, the two studies correlated well in 15 patients. CONCLUSION: Our results indicate that the FAIR technique allows reliable cerebral perfusion imaging at 0.5 T.     

单侧大脑中动脉狭窄程度与磁共振血流灌注相关性研究

目的:探讨大脑中动脉(MCA)狭窄程度与脑磁共振灌注加权成像(PWI)的相关性。方法:30例短暂性脑缺血发作(TIA)患者行高分辨力MRI检查并判断单侧MCA狭窄程度,同时行磁共振PWI检查,并对MCA不同狭窄状态下得出的患侧和镜像侧灌注参数,包括相对脑血容量(rCBV)、相对脑血流量(rBCF)、相对平均通过时间(rMTT)、相对达峰时间(rTTP)进行定量分析。结果:30例患者中,高分辨力MRI均可显示不同程度MCA狭窄,灌注均出现异常,患侧灌注参数rCBV、rCBF、rMTT、rTTP与镜像侧比较,差异均有统计学意义(P<0.05)。MCA狭窄率与rMTT延长百分率之间呈正相关性(r=0.45,P<0.05)。结论:高分辨力MRI对MCA狭窄程度的评估与PWI灌注参数之间存在正相关性,MCA狭窄程度与PWI相结合对于评价脑组织供血有一定的指导意义。     

MR perfusion imaging using the arterial spin labeling technique for breast cancer

Purpose:

To investigate the feasibility of perfusion imaging using an arterial spin labeling (ASL) technique for breast cancer.

Materials and Methods:

Thirteen female patients with primary breast cancers were included in this study. All examinations were performed on 1.5 Tesla MRI systems. Visual evaluations of the colored perfusion map and MRI perfusion values were assessed. MRI and computed tomography (CT) perfusion values were compared.

Results:

Thirteen of 14 tumor lesions could be visualized on the colored perfusion map. CT perfusion examinations were performed in eight breasts, and the relationship between the blood flow values of CT perfusion and of MR perfusion showed a significant correlation.

Conclusion:

Nonenhanced MR imaging by an ASL technique is valid for depicting breast cancer, and the MR perfusion value is thought to be helpful for quantitative diagnosis of breast cancer. J. Magn. Reson. Imaging 2012;436‐440. © 2011 Wiley Periodicals, Inc.     

Effect of vascular stenosis on perfusion-weighted imaging; differences between calculation algorithms

PURPOSE: To determine the most suitable postprocessing technique for magnetic resonance (MR) perfusion imaging in patients with vascular stenosis, by comparing the cerebral blood flow (CBF) maps of single photon emission tomography (SPECT) and perfusion MR imaging (MRI). MATERIALS AND METHODS: In 15 consecutive patients (14 men and one woman, mean age 73.9 +/- 6.0 years) with stenosis of common carotid artery (CCA) or internal carotid artery (ICA) of more than 75%, both brain perfusion MRI and brain perfusion SPECT were performed. From perfusion MR images, CBF maps were calculated with the first moment, singular value decomposition (SVD), and block circulant SVD (b-SVD) methods, and CBF maps from each algorithm were compared with those from SPECT. RESULTS: The b-SVD method had the best correlation with SPECT (R = 0.814), followed by the first moment method (R = 0.776) and the SVD method (R = 0.723). The b-SVD method has the least mean difference with SPECT (0.118), the first moment method also had less difference (0.121), and the SVD had greatest mean difference (0.164). CONCLUSION: Our results suggest that in patients with vascular impairment the b-SVD method will be the technique of choice rather than SVD or first moment method.     

Quantitative evaluation of mean transit times obtained with dynamic susceptibility contrast-enhanced MR imaging and with (133)Xe SPECT in occlusive cerebrovascular disease

OBJECTIVE: We report on quantitative mean transit time images obtained using dynamic susceptibility contrast-enhanced MR imaging after an IV bolus injection of a contrast agent. Our study compared cerebral hemodynamics measured using dynamic susceptibility contrast-enhanced MR imaging with the cerebral perfusion reserve obtained using dynamic (133)Xe single-photon emission computed tomography (SPECT). SUBJECTS AND METHODS: Seventeen patients with chronic cerebral artery occlusion or stenosis diagnosed by digital subtraction angiography were examined. Dynamic susceptibility contrast-enhanced MR imaging data were acquired using a multishot echoplanar sequence. Our procedure for quantification of mean transit time was based on the indicator dilution theory and deconvolution analysis. RESULTS: The increased mean transit time values obtained with dynamic susceptibility contrast-enhanced MR imaging correlated well (r=-0.789, p < 0.0001) with decreased cerebral perfusion reserve determined by performing dynamic (133)Xe SPECT before and after administration of acetazolamide. The mean transit time values in the regions with severely decreased perfusion reserve were significantly higher than those in the regions with normal or moderately decreased perfusion reserve (p < 0.0001 and p = 0.0004, respectively). CONCLUSION: Mean transit time images generated from dynamic susceptibility contrast-enhanced MR imaging data could be used to evaluate the extent of cerebral perfusion reserve impairment in patients with occlusive cerebrovascular disease.     

Distinction between high-grade gliomas and solitary metastases using peritumoral 3-T magnetic resonance spectroscopy,diffusion, and perfusion imagings

This study compared the effectiveness of relative cerebral blood volume, apparent diffusion coefficient, and spectroscopic imaging in differentiating between primary high-grade gliomas and solitary metastases. A 3.0-T MR unit was used to perform proton MR spectroscopy, diffusion imaging, and conventional MR imaging on 26 patients who had solitary brain tumors (14 high-grade gliomas and 12 metastases). All diagnoses were confirmed by biopsy. Twelve perfusion MR studies (8 high-grade gliomas and 4 metastases) were also performed. The results showed that the choline to creatine ratio and relative cerebral blood volume in the peritumoral regions of high-grade gliomas were significantly higher than they were in the metastases. The apparent diffusion coefficient values in tumoral and peritumoral regions of metastases were significantly higher than they were in the primary gliomas. Although conventional MR imaging characteristics of solitary metastases and primary high-grade gliomas may sometimes be similar, the peritumoral perfusion-weighted and spectroscopic MR imaging enable distinction between the two. Diffusion-weighted imaging techniques were complementary techniques to make a differential diagnosis between the two malignant tumors.