磁共振小肠造影多序列联合在儿童肠道疾病检查中的应用

目的：探讨磁共振小肠造影（M RE）多序列联合扫描在儿童肠道疾病检查中的应用价值。方法回顾性分析35例经临床、手术和病理证实为肠道疾病患儿的MRE多序列联合方案,包括T1 WI、T2 WI脂肪抑制、磁共振扩散加权成像（DWI）、单激发快速自旋回波（SSh‐TSE）、快速平衡稳态梯度回波（B‐FFE）平扫及脂肪抑制增强（FFE‐IP‐SPAIR）扫描。结果35例中,SSh‐TSE全景显示小儿肠管分布情况34例;DWI病变呈高信号29例;T1 WI及T2 WI脂肪抑制呈长T2信号3例,稍长T1稍短 T2信号2例,短T1短T2信号1例;增强扫描病变明显强化28例;无强化2例。结论 MRE多序列联合扫描图像信息量大,敏感性高,无电离辐射,可作为临床诊断儿童肠道疾病的重要检查手段。     

散发型Creutzfeldt-Jakob病的MRI表现

目的探讨散发型Creutzfeldt-Jakob病（sCJD）的MR特点。方法回顾性分析3例临床诊断为sCJD的患者资料，MR采用SE T1 WI、快速自旋回波（FSE）T2 WI、扩散加权成像（DWI）扫描，观察其MR表现特征。结果3例SE TI WI和FSE T2 WI序列对基底节区和皮质的病变显示不佳，DWI则可清晰地显示病变，额、顶、枕叶皮质最常受累，表现为高信号，病变可对称，也可不对称，皮层下区脑白质信号未见异常。双侧尾状核、丘脑也可受累，DWI上呈高信号。晚期脑实质广泛萎缩，以皮质为著。结论sCJD采用DWI序列结合其特征性的临床表现可作出较为准确的诊断。     

脾脏错构瘤的影像学表现分析

目的探讨脾脏错构瘤的影像学特点,提高对本病的诊断水平。方法回顾性分析10例经病理证实的错构瘤的影像学表现。结果本组脾脏错构瘤9例为单发病灶,1例为多发。.肿瘤体积较大,最大直径为4.5cm导致脾脏局部形态失常。CT扫描脾脏错构瘤为等或稍低密度。磁共振扫描肿块在T1WI及T2WI序列为等或稍低。DWI序列以低信号为主。增强扫描,肿瘤多呈明显、持续性强化,延时后与脾脏实质密度或信号相仿。结论脾脏错构瘤的CT及磁共振扫描具有一定的典型性表现,尤其是磁共振T1WI、T2WI及DWI序列并结合增强扫描,可以与其他脾脏病变区别。     

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。     

超高b值弥散加权联合T2加权序列诊断外周带前列腺癌的价值

目的 探讨超高b值弥散加权成像（DWI）联合T2加权成像（T2WI）诊断外周带前列腺癌（PCa）的临床应用价值。 方法 选取2018年12月1日至2019年10月1日在佛山市第一人民医院行超声引导下前列腺靶点穿刺、临床病理学确诊并于穿刺前后1个月内行前列腺MRI检查的PCa患者41例，年龄49~89岁，中位年龄69岁。所有患者均行3.0T超高b值（分别为2000、3000 s/mm2）的DWI及T2WI脂肪抑制序列MRI成像。以前列腺靶点穿刺病理学结果为“金标准”，分别计算T2WI、DWI（b=2000 s/mm2）、DWI（b=3000 s/mm2）、T2WI+DWI（b=2000 s/mm2）、T2WI+DWI（b=3000 s/mm2）对PCa的诊断灵敏度、特异度和准确率。采用受试者工作特征（ROC）曲线分析计算各方法诊断PCa的曲线下面积。 结果 41例患者中，PCa患者26例（通过临床结合穿刺点位置确诊为外周带PCa），良性前列腺增生患者15例。T2WI、DWI（b=2000 s/mm2）、DWI（b=3000 s/mm2）、T2WI+DWI（b=2000 s/mm2）、T2WI+DWI（b=3000 s/mm2）诊断PCa的灵敏度分别为0.962（25/26）、0.962（25/26）、0.962（25/26）、0.923（24/26）、0.923（24/26），特异度分别为0.400（6/15）、0.667（10/15）、0.876（13/15）、0.800（12/15）、1.000（15/15），准确率分别为0.756（31/41）、0.854（35/41）、0.926（38/41）、0.878（36/41）、0.951（39/41），ROC曲线下面积分别为0.681、0.814、0.914、0.872、0.972（P=0.056、0.001、＜0.001、＜0.001、＜0.001）。 结论 T2WI+DWI（b=3000 s/mm2）序列图像诊断PCa具有较高的准确率，有望成为一种可靠的诊断前列腺疾病的无创性检查方法。     

磁共振扩散加权成像在颅内表皮样囊肿中的诊断价值

目的：探讨磁共振扩散加权成像（DWI）在颅内表皮样囊肿中的诊断价值。方法：收集颅内表皮样囊肿病例16例，均行常规MRI和DWI检查，分析表皮样囊肿在T2WI、T1WI、增强扫描和DWI上的影像表现。结果：16例均呈长T2长T1信号，其中2例伴短T2间隔信号，增强扫描14例无强化，2例呈包膜和间隔强化。16例DWI上均呈明显高信号。结论：磁共振DWI在颅内表皮样囊肿中具有重要的诊断价值，可作为常规MRI的重要补充检查方法。     

常规MRI联合MR脑血管成像在围产期脑后部可逆性脑病综合征中的应用研究

目的：探讨常规磁共振成像（MRI）联合MR脑血管成像在围产期脑后部可逆性脑病综合征（PRES）诊断和鉴别诊断中的应用价值。方法：5例围产期PRES患者,平均年龄为26.5岁,且均于起病后2 d内行常规MRI和MR脑血管成像,MR脑血管成像包括MR脑动脉成像（MRA）和MR脑静脉成像（MRV）。结果：病变均累及双侧顶枕叶,另累及额叶2例,基底节区2例,桥脑1例,病变占位效应不明显。病变主要位于皮层下白质,其中1例累及皮质。病变T1WI呈低、等信号,T2WI及液体衰减反转恢复序列（FLAIR）呈高信号。3例磁共振扩散加权成像（DWI）呈等信号,表观扩散系数（ADC）图为高信号,另2例部分病变DWI为高或稍高信号。增强扫描以上病变未见明确强化,MRA、MRV未见明确异常。结论：围产期RPES的MRI表现较具特征性,常规MRI联合MR脑血管成像有助于本病的早期诊断和鉴别诊断。     

核磁弥散成像及增强扫描在诊断非缺血性颅脑病变中的意义

目的探讨核磁弥散成像及增强扫描在诊断非缺血性颅脑病变中的意义。方法收集经临床证实的非缺血性颅脑病变56例,均作常规MRI T2WI、T1WI、增强扫描及DWI,分析其DWI信号及增强表现。结果32例颅脑肿瘤、11例感染性病变、9例血肿、4例多发性硬化病例,病变在DWI上呈高或稍高信号。结论常规MRI T2WI、T1WI扫描图像,弥散成像及增强扫描在非缺血性颅脑病变的定性诊断中具有重要意义。     

新生儿低血糖脑损伤的高场磁共振表现

目的 初步探讨新生儿低血糖脑损伤的高场MRI表现.方法 回顾性分析经临床确诊的23例低血糖脑损伤新生儿的临床和MRI资料,MRI序列包括常规T1WI、T2WI、DWI及FLAIR序列.6例患儿有1个月后MR复查资料.结果 脑损伤早期DWI主要表现为高信号和ADC值降低,常规序列或表现正常,或表现T1WI稍低信号,T2WI稍高信号.受累脑区包括双侧顶枕叶23例,胼胝体11例,双侧基底节区9例,双侧大脑广泛受2例;6例随访,2例正常,4例顶枕叶出现软化灶.结论 新生儿低血糖脑损伤多发生在顶枕叶、胼胝体和基底节,DWI早期诊断优于常规序列,常规MRI结合DWI扫描对该病的早期诊断及预后评估具有重要价值.     

不同序列磁共振成像诊断脊柱损伤的价值研究

目的：探讨不同序列磁共振成像在脊柱损伤诊断中的应用价值。方法：选择急性脊柱外伤56例,均采用T1WI、T2WI、STIR、DWI及FLAIR等序列进行MRI检查,比较不同序列对椎体和脊髓损伤的诊断价值。结果：STIR显示损伤椎体内片状高信号113枚;T1WI示椎体内条状、片状低信号92枚;T2WI示椎体内条状、片状高信号87枚;DWI示椎体内片状高信号62枚、条状高信号23枚、等信号28枚;FLAIR示椎体变扁或楔形变72枚。脊髓损伤25例（25处病灶,其中颈段18处,胸段3处,圆锥4处）,;所有脊髓损伤STIR、T2WI、DWI呈斑片状或点状高信号,边缘模糊;T1WI示局部低信号12例,其中低信号内斑点状略高信号2例;FLAIR显示局部略高信号14例;所有序列均未见脊髓断裂病例。椎体骨折ADC值为（1.72±0.21）×10-3 mm2/s,正常椎体为（0.25±0.02）×10-3 mm2/s;脊髓损伤ADC值为（0.50±0.03）×10-3 mm2/s,正常脊髓为（1.04±0.08）×10-3 mm2/s。对于椎体骨折的诊断,STIR非常显著优于DWI、T1WI、T2WI及FLAIR（P〈0.01）;对于脊髓损伤的诊断,T2WI、STIR、DWI非常显著优于FLAIR及T1WI（P〈0.01）。结论：STIR可作为急性脊柱损伤的首选扫描序列,DWI可作为重要辅助序列,FLAIR不宜作为常规扫描序列。     

儿童急性局灶性细菌性肾炎的CT诊断(附12例报告)

目的分析儿童急性局灶性细菌性肾炎(acute focal bacterial nephritis,AFBN)的多层螺旋CT(MSCT)表现特征,探讨MSCT对AFBN的诊断及鉴别诊断价值。资料与方法经临床证实的12例AFBN患儿均行CT平扫及增强扫描,并行冠状位多平面重组(MPR)、容积再现(VR)、最大密度投影(MIP)重组,观察双侧肾脏形态、密度改变以及实质的灌注情况。12例尿培养均呈阳性。结果 CT表现分两型:典型者表现为单/双侧肾脏形态增大,实质灌注减低伴多发"楔"形或片状病灶,底部朝向肾外,尖端指向肾盂;不典型者肾脏内病灶呈肿块状,多单发,不均匀强化。结论 MSCT特别是增强扫描对于诊断儿童AFBN有一定优势,有助于提高对病变的诊断准确率。     

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.     

PROPELLER FSE磁共振扩散加权技术在诊断超急性和急性脑梗死中的价值

目的比较螺旋桨扫描技术(PROPELLER FSE)和平面回波成像(EPI)两种扩散加权成像(DWI)序列,探讨PROPELLER技术在DWI的应用价值。资料与方法选取67例临床疑诊急性脑梗死的患者分别行PROPEL-LER FSE DWI、EPI DWI和常规T1WI、T2WI、T2WI液体衰减反转恢复序列(FLAIR)检查,比较两种不同的DWI序列的图像质量,病灶检出率和对病变的显示程度。结果67例EPI DWI图像均不同程度地存在磁化率伪影,67例PROPELLER FSE DWI图像未见明显伪影及变形。67例中共发现并确诊46个急性脑梗死灶(4例为颅内多发病灶),其中病灶位于颅底区域12个,非颅底区域34个。PROPELLER FSE DWI和EPI DWI均可分辩出所有非颅底区域梗死灶。对12个颅底病灶PROPELLER FSE DWI检出率达100%,而EPI DWI可以明确诊断的7个,检出率达58.3%,病灶形态显示不充分或变形者3个,占25%,漏诊2个,漏诊率为16.7%。所有颅底区域病灶EPI DWI上信噪比(SNR)低于相应PROPELLER FSE DWI的SNR(t=-2.874,P<0.05)。结论PROPELLER FSE DWI能提高图像SNR,有效消除颅底磁化率伪影,改善图像质量,提高颅底病变的检出率。     

MRI and suspected acute pyelonephritis in children: comparison of diffusion-weighted imaging with gadolinium-enhanced T1-weighted imaging

Objectives

To evaluate the performance of diffusion-weighted imaging (DWI) against the reference standard of gadolinium-enhanced T1-weighted imaging (Gd-T1-WI) in children.

Methods

Thirty-nine consecutive patients (mean age 5.7 years) with suspected acute pyelonephritis underwent magnetic resonance imaging (MRI) including DWI and (the reference standard) Gd-T1-WI. Each study was read in double-blinded fashion by two radiologists. Each kidney was graded as normal or abnormal. Sensitivity and specificity of DWI were computed. Agreement between sequences and interobserver reproducibility were calculated (Cohen κ statistic and the McNemar tests).

Results

Thirty-two kidneys (41 %) had hypo-enhancing areas on Gd-T1-W images. The sensitivity and specificity of DWI were 100 % (32/32) and 93.5 % (43/46). DWI demonstrated excellent agreement (κ?=?0.92,) with Gd-T1-W, with no significant difference (P?=?0.25) in detection of abnormal lesions. Interobserver reproducibility was excellent with DWI (κ?=?0.79).

Conclusion

DWI enabled similar detection of abnormal areas to Gd-T1-WI and may provide an injection-free means of evaluation of acute pyelonephritis.

Key points

? Diffusion weighted magnetic resonance imaging (DWI) can confirm acute pyelonepritis. ? DWI provided comparable results to gadolinium enhanced T1-W MRI in acute pyelonepritis. ? Contrast medium injection could be avoided for diagnosing acute pyelonephritis by MRI. ? MRI with T2-WI and DWI provide a fast and comprehensive diagnostic tool.     

Magnetic resonance imaging and histologic findings of experimental cerebral fat embolism

RATIONALE AND OBJECTIVES: The purpose of this study was to determine whether cerebral fat embolism demonstrated reversible or irreversible findings in magnetic resonance (MR) imaging over time and to compare the features in MR images with histologic findings in a cat model. MATERIALS AND METHODS: MR images were obtained serially at 2 hours, 1 and 4 days, and 1, 2, and 3 weeks after embolization with 0.05 mL of triolein into the internal carotid artery in 19 cats. Any abnormal signal intensity and change in the signal intensity were evaluated on T2-weighted images, T1-weighted images, diffusion-weighted images (DWIs; including apparent diffusion coefficient [ADC] maps), and gadolinium-enhanced T1-weighted images (Gd-T1WI) over time. After MR imaging at 3 weeks, brain tissue was obtained and evaluated for light microscopic (LM) examination using hematoxylin-eosin and Luxol fast blue staining. For electron microscopic examination, the specimens were obtained at the cortex. The histologic and MR findings were compared. RESULTS: The embolization lesions showed hyperintensity on T2-weighted images, hyperintensity, or isointensity on DWIs, hypointensity, or isointensity on ADC maps and contrast enhancement on Gd-T1WIs at 2 hours. The T2-weighted hyperintensity extended to the white matter at day 1 and decreased thereafter. Contrast enhancement decreased continuously from day 1, and hyperintensity on DWI decreased after day 4. Hypointensity on ADC maps became less prominent after day 4. By week 3, most lesions had reverted to a normal appearance on MR images and were correlated with LM findings. However, small focal lesions remained in the gray matter of 8 cats and in the white matter of 3 cats on MR images, and this correlated with the cystic changes on LM findings. Electron microscopic examination of the cortical lesions that reverted to normal at week 3 in MR images showed that most of these lesions appeared normal but showed sporadic intracapillary fat vacuoles and disruption of the endothelial walls. CONCLUSIONS: The embolized lesions of the hyperacute stage were of 2 types: type 1 lesions, showing hyperintensity on DWIs and hypointensity on ADC maps, have irreversible sequelae, such as cystic changes; whereas type 2 lesions, showing isointensity or mild hyperintensity on DWIs and ADC maps, reverted to a normal appearance in the subacute stage.     

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.     

3.0T磁共振磁敏感加权成像对出血性脑梗死的诊断和鉴别诊断价值

目的探讨3.0T磁共振磁敏感加权成像(SWI)对出血性脑梗死的诊断和鉴别诊断价值。方法对430例脑梗死患者行MR的T1WI、T2WI、DWI与SWI扫描,分析T1WI、T2WI、DWI和SWI对出血性脑梗死检出率的差异和SWI对于出血性脑梗死的鉴别诊断价值。结果 SWI检出出血性脑梗死45例,T1WI检出20例,T2WI检出28例,DWI检出31例。结论 SWI较MR常规序列(T1WI和T2WI)和DWI序列可检出更多的出血性脑梗死病例;可早期发现脑梗死中的出血灶,明显优于MR常规序列(T1WI和T2WI)和DWI序列;具有一定的鉴别诊断价值;可作为出血性脑梗死检查的一线方法或常规序列。     

Growing Region Segmentation Software (GRES) for quantitative magnetic resonance imaging of multiple sclerosis: intra- and inter-observer agreement variability: a comparison with manual contouring method

Lesion area measurement in multiple sclerosis (MS) is one of the key points in evaluating the natural history and in monitoring the efficacy of treatments. This study was performed to check the intra- and inter-observer agreement variability of a locally developed Growing Region Segmentation Software (GRES), comparing them to those obtained using manual contouring (MC). From routine 1.5-T MRI study of clinically definite multiple sclerosis patients, 36 lesions seen on proton-density-weighted images (PDWI) and 36 enhancing lesion on Gd-DTPA-BMA-enhanced T1-weighted images (Gd-T1WI) were randomly chosen and were evaluated by three observers. The mean range of lesion size was 9.9-536.0 mm(2) on PDWI and 3.6-57.2 mm(2) on Gd-T1WI. The median intra- and inter-observer agreement were, respectively, 97.1 and 90.0% using GRES on PDWI, 81.0 and 70.0% using MC on PDWI, 88.8 and 80.0% using GRES on Gd-T1WI, and 85.8 and 70.0% using MC on Gd-T1WI. The intra- and inter-observer agreements were significantly greater for GRES compared with MC ( P<0.0001 and P=0.0023, respectively) for PDWI, while no difference was found between GRES an MC for Gd-T1WI. The intra-observer variability for GRES was significantly lower on both PDWI ( P=0.0001) and Gd-T1WI ( P=0.0067), whereas for MC the same result was found only for PDWI ( P=0.0147). These data indicate that GRES reduces both the intra- and the inter-observer variability in assessing the area of MS lesions on PDWI and may prove useful in multicentre studies.     

联合SWI与DWI在急性脑弥漫性轴索损伤中的应用价值

目的：评价联合磁敏感成像（SWI）与扩散加权成像（DWI）在急性期脑弥漫性轴索损伤中的应用价值。方法：32例脑弥漫性轴索损伤急性期患者,所有患者行常规MRI序列、DWI及SWI序列全脑扫描。结果：共检出病灶313个,T1WI 78个,T2WI 207个,FLAIR 292个,DWI 286个,SWI 297个。SWI显示245个病灶内分布斑片状、点状出血灶,其它序列共显示43个内分布出血灶。SWI、DWI病灶检出率高于常规T2WI（χ2=82.465,χ2=59.584;P〈0.01）,SWI、FLAIR及DWI病灶检出率无明显差异（χ2=3.052;P〉0.05）。结论：联合SWI与DWI有利于提高急性脑弥漫性轴索损伤的检出率,有助于准确评价病变的严重程度,SWI与DWI应作为急性脑弥漫性轴索损伤的常规扫描序列组合。     

MELAS 综合征的 MRI 诊断

目的：回顾性分析线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS)综合征的 MR 表现特点,提高对 MELAS 综合征早期诊断的能力。方法收集经临床诊断的 MELAS 综合征共16例,均由肌肉病理活检证实。所有患者均行 MR 平扫,其中3例行 ASL 扫描,15例行 MRA 检查,14例行 DWI 扫描,3例行 MRS 扫描,并回顾性综合分析其影像学资料。结果MRI 检查发现,本组 MELAS 综合征多表现为大脑半球各叶大小不等片状病灶,病变多位于大脑半球后部脑皮质区,向皮层下的白质蔓延,病灶的分布与脑血供分布不一致;自旋回波 T1 WI 呈低信号、T2 WI 呈高信号,FLAIR 呈高信号;DWI 呈高信号;3例行 MRS 分析提示病灶区典型乳酸峰;其中1例 MRA 检查提示病灶区分支血管增多,1例分支血管减少;3例行 ASL 检查提示病灶区高灌注。16例中4例随访病灶具有游走性、多变性、此起彼伏等表现,旧病灶有脑萎缩、脑软化等表现。16例行肌组织活检见破碎样红纤维(RRF);电镜见线粒体体积增大、数量增多,肌纤维粗细不等,少数萎缩变细。3例行线粒体基因测序发现线粒体 DNA(mtDNA)A3243G 点突变。结论DWI、MRS 及 ASL 在 MELAS 综合征诊断中具有良好的价值。