Rodent stroke induced by photochemical occlusion of proximal middle cerebral artery: evolution monitored with MR imaging and histopathology

PURPOSE: To longitudinally investigate stroke in rats after photothrombotic occlusion of proximal middle cerebral artery (MCA) with magnetic resonance imaging (MRI) in correlation with histopathology. MATERIALS AND METHODS: Forty-two rats were subjected to photochemical MCA occlusion and MRI at 1.5T, and sacrificed in seven groups (n=6 each) at the following time points: 1, 3, 6 and 12h, and at day 1, 3 and 9. T2-weighted (T2WI) and diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) map was performed in all rats. Contrast-enhanced T1-weighted imaging (CE-T1WI) was compared to intravital staining with Evans blue in one group for assessing blood-brain barrier (BBB) integrity. The brain was stained histochemically with triphenyl tetrazolium chloride (TTC) and processed for pathological assessment. The evolutional changes of relative lesion volume, signal intensity (SI), and the BBB integrity on MRI with corresponding histopathology were evaluated. RESULTS: The ischemic lesion volume reached a maximum around 12h to day 1 as visualized successively by DWI, ADC map and T2WI, implicating the evolving pathology from cytotoxic edema through vasogenic edema to tissue death. The ADC of brain infarction underwent a significant reversion after 12h, reflecting the colliquative necrosis. On CE-T1WI, BBB leakage peaked at 6h and at day 3 with a transitional partial recovery around 24h. The infarct volume on T2WI, DWI and ADC map matched well with that on TTC staining at 12h and at day 1 (p>0.05). CONCLUSION: The evolution of the present photothrombotic stroke model in rats could be characterized by MRI. The obtained information may help longitudinal studies of cerebral ischemia and anti-stroke agents using the same model.     

大鼠超急性期脑缺血的磁共振扩散加权成像研究

目的：利用磁共振扩散加权成像（DWI）评价大鼠超急性期脑缺血的诊断价值。方法：12只Wistar雄性大鼠,采用线栓法制作右侧大脑中动脉闭塞（MCAO）脑缺血模型,分别于栓塞后1h和6h行大鼠冠状位磁共振DWI、T2WI和T1WI检查,并测量缺血区DWI异常高信号的体积、表观扩散系数（ADC）值,将所测值进行比较。磁共振检查结束后处死大鼠,断头取脑行TTC染色,并与DWI结果进行比较。结果：大鼠MCAO后1h进行MRI扫描右侧大脑中动脉供血区DWI可见异常稍高信号,ADC为低信号,T2WI和T1WI均未见异常信号;MCAO后6hDWI可见明显高信号,较1hADC值显著减低（P〈0.01）,DWI上梗死灶体积显著扩大（P〈0.01）,T2WI显示缺血区异常高信号,T1WI可见稍低信号。TTC染色者均显示脑梗死灶,与MCAO后6h的DWI显示脑缺血范围一致。结论：DWI对超急性期脑梗死较常规MRI敏感,是超急性期脑缺血重要的检查方法。     

急性脑梗塞磁共振弥散加权成像的演变特征

目的：研究临床急性脑梗塞病变在弥散加权（DW）MRI上的表现规律。材料和方法：用单次激发平面回波弥散加权MRI和MRI其他技术对47例脑梗塞患者和14例非脑梗塞患者进行了对比研究。分别测量梗塞灶ACD图、DWI和T2WI的信号强度，绘出时间-信号强度图。分别在DWI和T2WI上测量梗塞面积．比较两者的关系。结果：急性脑梗塞发病后局部ACD逐渐降低．至12h达到峰值．以后逐渐升高。弥散加权MRI对急性脑梗塞病变非常敏感和特异，发病3h内T2WI为阴性，DW－MRI全部显示了梗塞灶；发病24h内T2WI所显示的梗塞灶面积明显小于DWI。发病7天内梗塞灶在DWI上与正常脑信号比均＞2．0．非脑梗塞病变均＜2．0。结论：急性脑梗塞病变在DW．MRI上有特征性演变规律，DW．MRI能快速、敏感、准确地诊断急性脑梗塞     

Do Transient Ischemic Attacks with Diffusion-Weighted Imaging Abnormalities Correspond to Brain Infarctions?

BACKGROUND AND PURPOSE: Our aim was to determine whether diffusion-weighted imaging (DWI) changes associated with transient ischemic attack (TIA) are reversible or correspond to permanent tissue injury. METHODS: Among 103 consecutive patients admitted for TIA, 36 (34.9%) had abnormalities on initial DWI (delay from TIA = 30 +/- 33 hours [mean +/- SD]). Thirty-three patients (59 DWI lesions) had an MR imaging follow-up (delay from TIA = 10.6 +/- 5 months) including fluid-attenuated inversion recovery, T2, DWI, and 3D T1-weighted sequences. For each lesion, we recorded the quantitative parameters on initial DWI (volume, apparent diffusion coefficient [ADC]) and performed a comparison between reversible and irreversible lesions. RESULTS: MR imaging failed to detect any permanent injury in 7 patients and identified subsequent infarct in regions corresponding to the original DWI abnormalities in 26 patients (79%). Of the 59 lesions initially identified on DWI, 45 (76.3%) were associated with permanent injury on follow-up MR imaging. The DWI volume was significantly larger (0.91 +/- 1.7 versus 0.21 +/- 0.21 cm(3), P = .003) and the ADC ratio values lower (79 +/- 15% versus 91 +/- 9%, P = .001) in lesions with subsequent infarct than in those that were fully reversible. CONCLUSION: By showing that most patients with DWI-positive TIAs share the same imaging outcome as stroke patients, our data provide additional support for the redefinition of TIA, which considers that all cases of transient deficit with characteristic neuroimaging abnormalities should be diagnosed as a stroke.     

The study of cerebral hemodynamics in the hyperacute stage of fat embolism induced by triolein emulsion

PURPOSE: The purpose of this study was to evaluate the cerebral hemodynamic change in the hyperacute stage of cerebral fat embolism induced by triolein emulsion, by using MR perfusion imaging in cat brains. METHODS: By using the femoral arterial approach, the internal carotid arteries of 14 cats were infused with an emulsion of triolein 0.05 mL. T2-weighted (T2WI), diffusion-weighted (DWI), apparent diffusion coefficient (ADC) map, perfusion-weighted (PWI), and gadolinium-enhanced T1-weighted (Gd-T1WI) images were obtained serially at 30 minutes and 2, 4, and 6 hours after infusion. The MR images were evaluated qualitatively and quantitatively. Qualitative evaluation was performed by assessing the signal intensity of the serial MR images. Quantitative assessment was performed by comparing the signal-intensity ratio (SIR) of the lesions to the contralateral normal side calculated on T2WIs, Gd-T1WIs, DWIs, and ADC maps at each acquisition time and by comparing the relative cerebral blood volume (rCBV), cerebral blood flow (CBF), and mean transit times (MTT) of the lesions to the contralateral normal side calculated on PWI. RESULTS: In the qualitative evaluation of the MR images, the lesions showed hyperintensity on T2WIs, enhancement on the Gd-T1WIs, and isointensity on DWIs and the ADC maps. In the quantitative studies, SIRs on the Gd-T1WIs, DWIs, and ADC maps peaked at 2 hours after infusion. The SIRs on the T2WIs peaked at 4 hours after infusion and decreased thereafter. On PWIs, the rCBV, rCBF, and MTT of the lesion showed no significant difference from the contralateral normal side (P = .09, .30, and .13, respectively) and showed no significant change of time course (P = .17, .31, and .66, respectively). CONCLUSION: The embolized lesions induced by triolein emulsion showed no significant difference in cerebral hemodynamic parameters from those on the contralateral normal side. The result may suggest that consideration of the hemodynamic factor of embolized lesions is not necessary in further studies of the blood-brain barrier with triolein emulsion.     

乳腺黏液腺癌MRI表现特征及其与病理对照研究

目的 探讨乳腺黏液腺癌MR平扫、动态增强(DCE)及DWI表现特征及其与病理表现的相关性.方法 MR枪查采用1.5 T MR扫描仪及乳腺专用线圈,包括MR平扫、3D DCE-MRI以及b值分别为500和1000 s/mm2的DWI.对8例行乳腺MR检查并经手术病理证实的乳腺黏液腺癌,依据乳腺影像报告和数据系统(BI-RADS)MRI标准,回顾性分析病变形态学、T1WI及T2WI信号强度、肿块内部强化特征及动态增强曲线类型、DWI上ADC值表现,并与病理对照,乳腺黏液腺癌病理诊断依据2003年WHO乳腺肿瘤病理学标准.结果 8例乳腺黏液腺癌(5例单纯黏液腺癌,3例混合型黏液腺癌)的黏液含昔为60%～90%.8例在MRI上均表现为肿块,平扫T1WI呈低信号,T2WI呈高和明显高信号.动态增强后,1例表现为不均匀轻微强化,2例表现为内部欠均匀的渐进性强化,其余5例于动态增强早期时相均表现为边缘明显强化,肿块内部结构呈渐进性强化,强化方式呈由边缘强化向中心渗透趋势.于DWI上病变均表现为明显高信号,平均ADC值在b值500 s/mm2时为(2.41±0.28)×10-3mm2/s,b值1000 s/mm2时为(2.06±0.14)×10-3mm2/s,分别高于正常乳腺组织的(1.71±0.32)×10-3和(1.43±0.24)×10-3mm2/s.结论 乳腺黏液腺癌在MR平扫T2WI、DEC及DWI表现均不同于常见的浸润性导管癌,这些特征性表现反映了其特殊的病理类型,MR多种成像序列相结合可对乳腺黏液腺癌在术前作出正确诊断.     

MR扩散加权成像对脑实质内表皮样囊肿的诊断价值

目的探讨MR扩散加权成像(DWI)对脑实质内表皮样囊肿(EC)的诊断价值。资料与方法回顾性分析6例脑实质内EC的常规MRI和DWI的信号特征。定量测定EC、正常脑白质和脑脊液(CSF)的平均表观扩散系数(mADC)值,并比较常规MRI和DWI各自诊断的准确性。结果(1)4例位于幕下小脑实质内,其中1例合并蛛网膜囊肿。1例呈巨块状跨左侧额、颞叶实质,另1例位于左颞叶内;(2)2例为均匀性长T1、长T2信号,类似CSF信号,4例表现为不均匀性囊实性混杂信号,其内可见漩涡状或卷发状短T1信号。所有病灶DWI上均表现为明显高信号、ADC图表现为等低、等高信号,部分病灶内信号不均;所有病灶均无灶周水肿信号;增强后均无异常强化;(3)所有EC的mADC值均较CSF值显著减低(t=39.97,P<0.001),较脑实质值显著增高(t=4.73,P<0.01);(4)单纯常规MRI对EC的诊断正确率为50%(3/6),结合DWI后的正确率为100%(6/6)。结论DWI有助于确诊脑实质内EC,对预防术中化学性脑膜炎的发生有重要意义。DWI应作为颅内囊性病灶检查时的常规序列。     

双b值扩散加权成像在脑梗死诊断中的应用

目的:比较双b值DWI对脑梗死体积及ADC值测量的影响,探讨较高b值DWI在脑梗死诊断中的应用价值。方法:回顾性研究30例脑梗死患者,年龄44～84岁,平均67岁,发病时间3～6d,DWI取b值1000和2000s/mm2,分析脑梗死DWI及ADC图,测量兴趣区与对侧正常部位的扩散系数(ADC)并计算相对扩散系数(rADC),测量并计算梗死灶体积。结果:急性和亚急性脑梗死灶均扩散受限,DWI呈高信号、ADC图呈低信号。与b值1000s/mm2相比,b值2000s/mm2DWI示脑灰白质对比度增加,病灶显示更清晰,还能发现新病灶。不同b值下rADC比较没有统计学意义(P=0.884,P>0.05),同侧ADC有统计学意义(P=0.005,P<0.05);对侧ADC有显著统计学意义(P<0.001)。较高b值下梗死体积较低b值增加,且有统计学意义(P=0.04,P<0.05)。结论:DWI是检测脑梗死的重要技术手段,rADC不受b值影响,rADC降低可指导脑梗死诊断;较高b值DWI上脑梗死灶体积测量更准确,有利于观察病灶演变和指导临床治疗。     

Time course of cerebral infarction in the middle cerebral arterial territory: deep watershed versus territorial subtypes on diffusion-weighted MR images

PURPOSE: To examine possible differences between the evolution of cerebral watershed infarction (WI) and that of territorial thromboembolic infarction (TI) by using diffusion-weighted (DW) and T2-weighted magnetic resonance (MR) images and apparent diffusion coefficient (ADC) maps. MATERIALS AND METHODS: Fourteen patients with TI and nine with WI underwent MR imaging from the acute to chronic infarction stages. ADC maps were derived from DW images. Lesion-to-normal tissue signal intensity ratios on ADC maps (rADC), echo-planar T2-weighted images, and DW images were calculated. Lesion volumes at acute or early subacute infarction stages were measured on DW images, and final lesion volumes were estimated on fluid-attenuated inversion-recovery images. RESULTS: Analysis of variance revealed a significant difference in temporal evolution patterns of rADC between WI and TI (P <.001). rADC pseudonormalization following TI began about 10 days after symptom onset, but that following WI did not occur until about 1 month after symptom onset. The Pearson correlation coefficient between final and initial infarct volumes was 0.9899 for both infarction subtypes, indicating that the initial ischemic injury volume measured at the acute or early subacute stage predicted the final lesion volume fairly well. CONCLUSION: The evolution time of ADC is faster for TI than for WI. This difference, which likely originates from the different pathophysiologic and hemodynamic features of the two infarction types, might account for the relatively large range of ADC values reported for the time course of ischemic strokes.     

超急性脑梗死再灌注扩散加权-灌注磁共振成像及病理变化

目的应用扩散-灌注(DWI-PI)磁共振成像技术对改良线栓法建立的超急性脑梗死再灌注模型进行实验研究,并与病理结果对照.明确该技术对超急性脑梗死再灌注的评价作用.材料与方法 50只SD大鼠,随机分成5组,A组(10只)行假手术作对照,其余按栓塞时间30 min、1、3、6 h均分成B、C、D、E 4组;行DWI、PI和常规质子密度加权成像(PDWI)、T2WI、T1WI扫描;DWI和PI原始图像重建获得表观扩散系数(ADC)、脑血容量(CBV)、脑血流量(CBF)、平均通过时间(MTT)参数形态图.观察各栓塞时间点和再灌注2、24 h后各项参数变化,并将其结果与四氮唑红(TTC)染色和病理观察对比.结果 A组DWI、PI成像无异常信号,病理观察和TTC染色无变化.B组再灌注2 h DWI高信号消失,ADC值恢复正常化(88.27±1.92)%,24 h继发性ADC值降低和DWI高信号;C组再灌注2 h后ADC值轻度升高,24 h明显降低;D、E组再灌注2、24 h ADC值轻度降低或基本不变;各组再灌注后24 h DWI显示病灶范围无明显扩大.A、B组再灌注后PI各参数指标(CBV、CBF、MTT)恢复和维持正常,而D、E组的信号强度-时间曲线图有3种表现,分别为高灌注、低灌注和正常灌注.超急性脑梗死再灌注后DWI显示的缺血范围与TTC异常染色(白色)范围无显著性差异(方差分析,P＞0.05).结论在超急性脑梗死中大脑中动脉栓塞30 min再灌注后初次DWI异常信号消散是暂时的,以后会发生继发性DWI异常信号,再灌注后初次DWI异常信号消散区24 h后观察到神经元坏死;再灌注可限制病灶进一步扩大,保护缺血半影区.     

Multimodal MR examination in acute ischemic stroke

In recent years, combined diffusion-weighted imaging (DWI) with perfusion imaging (PI) has become an important investigational tool in the acute phase of ischemic stroke, as it may differentiate reversible from irreversible brain tissue damage. We consecutively examined 20 subjects within 12 h of stroke onset using a multiparametric magnetic resonance (MR) examination consisting of DWI, mean transit time (MTT) as PI parameter, and MR angiography (MRA). T2-weighted and fluid-attenuated inversion recovery (FLAIR) on day 7 were also acquired in order to obtain final infarct volume. The following MR parameters were considered: volumetric measures of lesion growth and MTT abnormalities, quantification of regional apparent diffusion coefficient (ADC) and visual inspection of MRA findings. Our results showed: (1) an acute DWI lesion was not predictive of lesion growth and the DWI abnormality did not represent the irreversibly infarcted tissue; (2) ADC values in the ischemic penumbra could not predict tissue at risk; (3) the DWI–PI mismatch did not predict lesion growth, and the PI abnormality overestimated the amount of tissue at risk; and (4) patients with proximal middle cerebral artery occlusion had greater initial and final infarct volumes. This study did not demonstrate the prognostic value of a multimodal MR approach in early ischemic stroke; MRA alone provided predictive information about the volumetric evolution of the lesion.     

Time evolution of cerebral perfusion and apparent diffusion coefficient measured by magnetic resonance imaging in a porcine stroke model

PURPOSE: To demonstrate the feasibility of sequential diffusion-weighted (DW) and perfusion-weighted (PW) magnetic resonance imaging (MRI) of a recently developed porcine stroke model and to evaluate the evolution of cerebral perfusion and the apparent diffusion coefficient (ADC) over time. Materials and Methods In five pigs, DW imaging (DWI) and PW imaging (PWI) was carried out for 7 hours after stroke onset, starting 1 hour after middle cerebral artery occlusion (MCAO). RESULTS: The DWI lesion volume increased significantly with time, and final DWI lesion volume correlated well with lesion area on histological sections (r = 0.910). T2 changes could be recognized 3 hours after stroke onset. At 1 hour the ADC ratio (ischemic lesion/contralateral side) was reduced to 0.81 in the caudate-putamen and to 0.87 in the cortex, and the cerebral blood flow ratio was reduced to 0.40 in the caudate-putamen and 0.51 in the cortex. CONCLUSION: The level of flow reduction in the caudate-putamen and the cortex after 1 hour is in good correlation with human thresholds of irreversible and reversible ischemic damage, and accordingly, this model might be a model for mechanisms of infarct evolution and therapeutic intervention.     

扩散加权成像诊断超急性和急性脑梗塞的应用价值

目的:探讨DWI和ADC图诊断超急性和急性脑梗塞的价值.材料和方法:14例脑梗塞患者(超急性期6例,急性期8例)采用1.5T MR机进行扫描,对DWI、ADC图及常规T1WI、T2WI进行对比研究分析.结果:超急性和急性脑梗塞DWI均表现为高信号,ADC图均表现为低信号,DWI对病变显示达100%.6例超急性期脑梗塞患者仅DWI可显示病变而常规T1WI、T2WI无任何相应的异常发现.全部病灶ADC值均低于其相对应的正常脑组织.结论:DWI对急性脑梗塞诊断敏感、准确,且能对脑梗塞作定量分析.     

急性大脑中动脉阻塞模型的磁共振弥散成像及相关病理基础研究

目的观察兔大脑中动脉阻塞后常规MRI及DWI表现,阐明活体脑缺血后DWI的演变规律及其病理生理机制方法40只成年新西兰大白兔随机分成2组,对照组4只,实验组36只实验组采用Yamamoto法制作急性大脑中动脉阻塞(MCAO)模型,对照组仅曝露大脑中动脉,而不结扎观察MCAO后缺血区在各时段ADC值的变化规律,并进行病理学检查结果对照组:T2WI及DWI均无高信号出现,光镜检查均无异常改变实验组:DWI上,MCAO后0.5h基底节区出现高信号;T2WI最早于2h出现高信号,早期ADC值快速下降的病理基础是缺血后细胞内的水含量的增加;ADC值下降减慢及相对平台期的病理基础是血脑屏障破坏的逐渐加重及血管源性水肿的出现;而ADC值的上升的病理基础是细胞的死亡、溶解,血脑屏障的破坏结论早期的扩散异常区域并不意味着病灶已发生梗死,当持续缺血达6h以上,脑组织将产生不可逆的损伤     

扩散加权成像在急性脑缺血性中风诊断中的价值

目的　评价扩散加权成像 (DWI)技术在急性脑缺血性中风 (AIS)急诊MR检查中的价值和对急诊MR诊断质量的影响。资料与方法　回顾分析 86例AIS急诊MR检查资料 ,将距症状发作 1 0h内进行急诊MR检查者定为A组 ,1 0h后急诊MR检查者定为B组。利用双盲法 ,对DWI和TSET2 WI、FLAIRT2 WI、SET1 WI所见作对照分析。结果　A组 ,TSET2 WI+FLAIRT2 WI+SET1 WI对AIS新梗死灶显示能力为DWI的 32 .98% ,两者具有显著性差异(P <0 .0 1 )。B组 ,TSET2 WI+FLAIRT2 WI+SET1 WI与DWI具有相同的显示能力。AIS新梗死灶DWI呈高信号 ,ADC图呈低信号。结论　DWI能早期、超早期诊断AIS ,降低错、漏诊率 ,提高AIS常规急诊MR诊断质量     

磁共振扩散加权成像对急性腔隙性脑梗死的诊断价值

目的 :探讨急性腔隙性脑梗死患者的脑部磁共振扩散加权成像 (MRDWI)表现及其ADC值变化。方法 :搜集急性脑梗死病例 5 4例 ,根据MRI显示病灶的位置、形态和最大直径 ,分为急性腔隙性脑梗死组 ( 3 9例 )和急性大面积脑梗死组 ( 15例 )。选正常对照组 5例。结果 :3 9例急性腔隙性脑梗死病例均有不同程度MRDWI表现 ;其ADC值与急性大面积脑梗死组之间差异无显著性意义。结论 :MRDWI对急性腔隙性脑梗死的诊断具有很好的敏感性和特异性 ,结合ADC图和ADC值则可作出更准确的诊断     

Intraparenchymal epidermoid cysts in the brain: diagnostic value of MR diffusion-weighted imaging

AIM: To evaluate the value of magnetic resonance (MR) diffusion-weighted imaging (DWI) and apparent diffusion coefficients (ADC) maps in the diagnosis of intraparenchymal epidermoid cysts (ECs). MATERIALS AND METHODS: Six cases of histopathologically proven intraparenchymal ECs were studied. All patients were examined with conventional MR (T1WI, T2WI, contrast-enhanced T1WI) and DWI sequences. Along with the mean ADC values (mADC) of the ECs, the cerebrospinal fluid (CSF) and grey matter (GM) were measured. Qualitative and quantitative assessments, as well as MRI findings, were retrospectively analysed using a double blind method by three radiologists in consensus. RESULTS: Four lesions were located in the cerebellum, among them, one was accompanied by an arachnoid cyst; one huge lesion crossed the parenchyma of the frontal and temporal lobes; the other was located in the left temporal lobe. Two lesions had a homogeneous CSF-like intensity on both T1WI and T2WI. The other four were of mixed-intensity on both T1WI and T2WI. All lesions were strikingly hyperintense on DWI, and iso- or slightly hypointense on ADC (relative to the brain). The mADCs of the ECs were significantly higher than that of GM, but significantly lower than that of CSF. Three cases (3/6) were accurately diagnosed using conventional MR sequences without DWI, but in the remaining three cases, correct diagnosis could only be made with help of DWI. CONCLUSION: DWI sequences can facilitate the diagnosis of intraparenchymal ECs, thus alerting surgeons of the risk of chemical meningitis at surgery. The MR findings of intraparenchymal ECs are basically as the same as those of extracerebral ECs, but the former is likely to have a mixed signal. The hyperintense signal of ECs on DWI is probably caused by the T2 shine-through effect in tumour tissue.     

3.0T MR扩散张量成像在脑梗死诊断中的应用

目的：探讨3.0T磁共振扩散张量成像（DTI）对脑梗死的诊断价值。方法：对75例不同时期脑梗死患者进行MRI常规检查、扩散加权成像（DWI）及DTI检查,重建平均扩散系数（DCavg）图及部分各向异性（FA）图。以T2WI与DWI图像为参照,测定各期脑梗死灶及对侧正常脑组织的平均DCavg值、平均FA值,并进行统计学处理。结果：与对侧正常脑组织相比,脑梗死平均DCavg值在超急性期及急性期显著减低（P〈0.01）,随着时间延长呈逐渐恢复升高的变化趋势;脑梗死平均FA值在超急性期无一致性变化,与对侧正常脑组织相比差异无统计学意义（P〉0.05）,可轻度升高或轻度降低,随着病程进展呈不可恢复持续减低规律。结论：联合DCavg值与FA值可对脑梗死进行更精确的临床分期,有助于及时准确了解脑梗死的病理生理改变,为临床治疗及预后判断提供依据。     

非特异性肉芽肿性前列腺炎的MRI表现

目的：探讨非特异性肉芽肿性前列腺炎的MRI表现特点。方法：8例经病理证实的非特异性肉芽肿性前列腺炎患者行T1WI、T2WI、扩散加权成像（DWI）及增强检查,回顾性分析其临床及影像学表现特点。结果：8例患者病灶均为结节灶,以右侧前列腺中部外周带多见（5／8）。病灶在T。wI上呈低、稍低及等信号,T2WI上主要为低及稍低信号,DWI上表现为高及稍高信号,表观扩散系数（ADC）图上呈局灶性低信号。4例患者行动态增强MRI检查,病灶明显强化,时间一信号强度曲线呈Ⅰ型（1例）或Ⅱ型强化（3例）。结论：非特异性肉芽肿性前列腺炎的常规MRI检查缺乏特异性,而动态增强扫描可能有助于该病的诊断及鉴别诊断。     

The role of diffusion – Weighted MRI in evaluation of prostate cancer

The aim of work

To illustrate the role of T2WI combined with diffusion WI (DWI) in the evaluation of patients with prostate cancer.

Patients and methods

This prospective study included 36 patients (mean age 61) with clinical suspicion of prostate cancer using surface coil at 1.5 T MR Unit. Axial, coronal, and sagittal high resolution (HR) T2WI were performed, DWI was applied using a single-shot echo-planar imaging sequence in axial orientation. Regions of interest were drawn on ADC maps on the site of visible restricted diffusion as well as the normal tissue, then the ADC value was calculated. Considering histopathological diagnosis the standard of reference, the results of T2WI alone were compared with those of combined T2WI and DWI.

Results

In this prospective study, 36 men were examined and T2WI, DWI, ADC map and ADC values were measured. T2 low SI was detected in the peripheral zone of the prostate of 36 patients, and restricted diffusion in 31 patients.

Conclusion

Our study indicates that the addition of the ADC map and DWI to T2WI provide significantly more accurate results for prostate cancer detection and staging.