宫颈癌的MRI诊断与分期研究

目的 探讨宫颈癌的MRI表现，前瞻性评价MR成像对宫颈癌术前分期的价值。方法 98例经病理证实的宫颈癌患者行MR检查，其中45例进行了手术，术前3－15d（平均7．5d)内行盆腔的轴面SE T1WI，轴面及矢状面快速自旋回波（TSE）T2WI，冠状面脂肪抑制（SPIR）TSE T2WI以及钆喷替酸葡甲胺（Gd-DTPA)增强后轴面、冠状面、矢状面SE T1WI扫描。在MR图像上观察原发肿瘤的位置、信号特征及侵犯范围。MRI所见与手术病理所进行对比。结果 宫颈癌的MRI表现颇具特征性，T2WI呈较高信号，与宫颈基质低信号及子宫内膜、宫旁脂肪组织高信号有良好对比，T1WI呈等或低信号，Gd-DTPA增强后T1WI可轻度强化。33例出现信号不均匀表现，病理上可为假腺腔、坏死及角化珠。MRI对宫颈癌部位判断的准确度为100％。对宫旁侵犯判断的准确度为88．9％，特异度为90．6％，敏感度为84．6％。对宫颈癌分期总的准确度为88．9％。结论 MRI能多方位清晰显示宫颈癌瘤灶及侵犯范围与途径，明显优于其他影像学检查方法，MRI对术前宫颈癌分期明显优于临床，应成为宫颈癌术前常规的影像检查方法。     

胼胝体非出血性挫伤的MRI诊断(附四例报告)

目的报告4例胼胝体非出血性挫伤的MRI表现。材料与方法回顾性分析4例胼胝体非出血性挫伤的MRI资料;3例为车祸伤,1例为坠落伤,都进行了CT和MR非增强检查。结果4例胼胝体挫伤灶2例位于压部、1例位于干部、1例累及胼胝体大部。CT扫描胼胝体区未见异常密度。MR图像上均表现为等或略低T1WI信号与明显高T2WI信号,未见出血信号。SE或FSET2WI(轴位或矢状位)对病变显示清楚,而FLAIR序列则能抑制脑脊液的高信号、使病变显示更加突出。1例4个月后MR检查显示挫伤灶演变为类似脑脊液信号的软化灶。4例中3例还合并颅内多处脑挫伤和血肿。结论胼胝体非出血性挫伤较少见,CT检查难以发现病灶MR是其最佳的影像学检查手段,轴位与矢状位SE或FSET2WI是显示挫伤灶的主要序列,FLAIR序列对病灶的显示更佳。本病典型的MRI表现是胼胝体区T1WI等或略低信号、T2WI高信号,无出血信号;胼胝体非出血性挫伤可合并颅内多发性外伤性改变。     

低场MR FLAIR序列在脑白质疏松症诊断中的应用价值

目的：探讨低场MRI液体衰减反转恢复（fluid liquid attenuated inversion recovery,简称FLAIR） 序列在脑白质疏松症（LA）影像诊断中的应用价值。方法：采用0．3T低场MRI扫描仪对70例LA进行自旋回波（SE）序列和FLAIR序列成像，分析LA在SE及FLAIR序列中的影像表现，比较两种成像序列对LA病变的显示效果。结果：LA MRI表现为侧脑室周围和／或深部脑白质形态不规则、边缘模糊的斑点及点片状异常信号影，SE序列呈等T1或长T1、长T2信号改变，FLAIR呈略高或高信号改变；FLAIR序列成像与SE序列T2WI对LA病灶显示的满意程度及对病变的分级诊断均无明显差异。结论：在低场条件下采用FLAIR序列诊断LA，其成像效果并不比常规SE序列优越。     

垂体微腺瘤MRI诊断(附25例分析)

目的：探讨和总结25例垂体微腺瘤的磁共振成像（MRI）表现。方法：对25例经MRI平扫：冠状位于SE序列T2加权成像（T2WI）、FFE序列T1加权成像（T1WI）,及行Gd-DTPA增强扫描：冠状位下FFE序列T1WI、矢状位下FFE序列T1WI检查,经手术切除得到病理证实的病例进行分析,其中7例行动态增强和延迟扫描。结果：25例垂体微腺瘤均位于垂体前叶,单发19例,其中14例位于垂体右侧部,多发6例。MRI平扫24例（T1WI）为低或稍低信号、1例为高或稍高信号;23例（T2WI）为高或稍高信号,但2例为等或稍低信号,增强后即刻扫描25例均为低或稍低信号,7例动态增强扫描延迟25－30min后1例有明显强化。结论：垂体微腺瘤MRI表现有一定特征性,MRI对诊断垂体微腺瘤有较大价值。     

屈颈MRI对青年性上肢远端肌萎缩症的诊断价值

目的评价屈颈MRI对青年性上肢远端肌萎缩症的诊断价值。方法男性患者5例，平均年龄21岁，临床表现为一侧或两侧上肢远端肌萎缩。对照组为健康志愿者，21岁男性8例。2组均行常规及屈颈颈椎MR平扫，矢状、轴面SET1WI、T2WI、液体衰减反转恢复（FLAIR）序列扫描。结果常规颈椎扫描：5例患者下段颈髓变细；屈颈位MR扫描：下颈段颈6以下脊髓前屈、变扁平，矢状径4～6mm，硬膜囊后壁前移，硬膜后间隙明显增宽，可见多发条状、迂曲流空信号影及软组织信号。对照组：常规扫描，下颈段脊髓（颈6～胸2）可见颈膨大，屈颈位脊髓略变细（6～7mm），硬膜囊后壁无前移，硬膜后间隙未见扩张血管影。结论屈颈MRI有助于显示下颈段脊髓及硬膜囊改变，结合临床资料可准确诊断青年性上肢远端肌萎缩症。     

脊髓血管母细胞瘤的MRI表现

目的评估脊髓血管母细胞瘤的MRI表现。资料与方法回顾性分析7例经手术病理证实的脊髓血管母细胞瘤的MR／表现。7例均行常规MR扫描,应用T1、T2加权序列作轴面、矢状面扫描,且均应用T1WISE作轴面、矢状面、冠状面增强扫描。结果7例肿瘤在T1WI上呈等信号、低信号或等、低混杂信号,在T2WI上呈高信号或混杂信号,增强后均一或不均一强化。其中5例伴有脊髓空洞,4例可见血管流空效应,2例伴有瘤周水肿。结论脊髓血管母细胞瘤的MRI表现具有特征性。MRI还有利于明确肿瘤的位置和范围,以及外科治疗计划的制定。     

硅胶乳腺假体并发症的低场MRI诊断

目的 探讨硅胶乳腺假体并发症的低场MRI表现及MRI检查的价值.方法 8例因美容需要均植入硅胶乳腺假体共16个,采用GE Signa Ovation EXCITE 0.35T开放式永磁型磁共振成像仪,使用自制固体泡沫乳腺窝垫,选择轴面自旋回波(SE)T1WI序列,轴面及矢状面快速恢复快速自旋回波(FRFSE)T2WI序列, 轴面短反转时间反转恢复序列(STIR)进行扫描.结果 硅胶乳腺假体破裂13个,其中内膜破裂11例,表现为"舌"征、"花襻"征或"套索"征;外膜破裂2例,表现为假体外乳腺组织内或胸大肌后间隙内散在或弥漫的硅胶粒,包膜周围见反应性渗液,呈T1低信号、T2高信号,STIR高信号.均经手术证实.结论 MRI是目前评价硅胶乳腺假体并发症敏感而准确的影像学方法.     

青少年急性单纯膝关节软骨骨折的MRI表现

目的分析青少年急性单纯膝关节软骨骨折的MRI表现，以提高对MRI表现的认识。方法回顾性分析经关节镜手术证实的26例27处急性单纯膝关节软骨骨折的MRI表现，重点观察软骨、软骨下低信号线和软骨下骨髓的改变。26例均采用矢状面和冠状面扫描，矢状面应用快速小角度激发成像序列T1WI加脂肪抑制（FLASH-FS-T1WI）、SE-T1WI和三维稳态进动快速成像序列T2WI加脂肪抑制（FISP-3D-FS-T2WI）序列，冠状面应用多回波数据结合成像序列T2WI（ME-T2WI）和SE—T1WI，有5例还加扫了横轴面ME-T2WI。结果26例27处软骨骨折中髌骨8处，股骨内髁7处，股骨外髁11处，胫骨平台1处。单纯软骨骨折有3种类型，软骨全层缺损（7处，其中髌骨3处、股骨内髁2处、股骨外髁1处、胫骨平台外后髁1处）、裂隙状软骨骨折（3处，其中股骨内髁2处、股骨外髁1处）、软骨部分缺损（17处，其中髌骨5处、股骨内髁3处、股骨外髁9处）。关节镜手术发现2l例有关节内软骨游离体，而MRI仅发现3例。全部患者软骨骨折附近均有骨髓挫伤，软骨下低信号线形态、信号均正常。结论膝关节股骨和胫骨平台软骨骨折采用矢状面FLASH-FS-T1WI、SE-T，WI和FISP-3D-FS-T2WI序列及冠状面ME．T2WI、SE-T1WI，髌骨软骨骨折加扫横轴面ME-T2WI序列可显示急性单纯膝关节软骨骨折的部位、范围和类型，是软骨骨折最好的无创性检查方法。     

儿童永存镰状窦的MRI表现

目的探讨儿童永存镰状窦的MRI表现。资料与方法回顾性分析5例镰状窦患儿的MRI资料,均行MR平扫,获得T1WI、T2WI及液体衰减反转恢复序列(FLAIR)图像,4例增强扫描,1例行磁共振静脉成像(MRV)检查。结果 5例中,1例合并Dandy-Walker畸形,1例合并小脑蚓部肿瘤。其余3例未见合并静脉窦血栓或肿瘤压迫等导致静脉窦异常开放因素,直窦存在正常引流功能,考虑永存镰状窦。结论 MR T1WI序列矢状位图像以及增强MRV图像对永存镰状窦诊断具有重要价值。     

MRI在宫颈癌术前诊断及分期的价值

目的：探讨宫颈癌的MRI表现，并评价MRI对宫颈癌分期的临床价值。方法：24例宫颈癌患者均行轴位T1WI（SE），轴位、矢状位T2WI（TSE），矢状位T2WI压脂序列扫描，以及宫颈局部薄层斜轴位T2WI扫描。所用病例均经病理学证实。总结其MRI影像特点，将MRI术前分期结果与手术病理分期及临床分期进行比较。结果：（1）在T1WI，肿瘤呈等信号，与正常宫颈组织及宫旁组织分界不清。在T2WI，宫颈癌肿瘤组织通常呈不均匀中等信号，与正常宫颈组织（低信号）及宫旁结构（明显高信号）之间具有良好的对比，对判断肿瘤大小及侵犯范围有价值。（2）MRI术前分期结果、临床分期结果与病理分期结果比较，准确率分别为83．33％、79．17％。结论：MRIT2WI可清晰显示宫颈癌肿瘤侵犯范围（尤其是有无宫旁侵犯），对宫颈癌的分期判断客观准确，对临床制订治疗方案及预后评估有重要意义。     

增强FLAIR T2WI诊断脑膜转移瘤的价值

目的:探讨脑膜转移瘤的MRI表现及增强后FLAIR序列T2WI的诊断价值。方法:回顾性分析20例脑膜转移瘤患者的病例资料,其中硬脑膜转移瘤5例,软脑膜转移瘤15例。所有病例行常规MRI平扫及SE T1WI和FLAIR序列T2WI增强扫描并进行对比分析。结果:MRI平扫检出6例,病灶边界均显示不清;MRI增强扫描检出所有病例,SE-T1WI上病变主要表现为脑膜的线状和/或结节状强化,FLAIR T2WI对软脑膜转移瘤病灶范围的显示更清楚,可鉴别强化的血管与病变。结论:MRI增强扫描是诊断脑膜转移瘤的重要检查方法,增强后FLAIR序列T2WI与SE T1WI同时使用,可提高对软脑膜转移瘤的检出率及诊断准确性。     

STIR MR imaging of the orbit

Fifteen patients with CT-documented orbital lesions were evaluated with MR imaging at 1.5 T with both conventional spin-echo (SE) and short inversion time inversion recovery (STIR) sequences. Fat signal was reliably nulled at inversion times of approximately 120-200 msec in all cases, thereby allowing clear detection of all retrobulbar lesions and normal structures on STIR images as markedly hyperintense relative to fat. All lesions were also clearly depicted on SE images; in fact, short repetition time/short echo time SE sequences were at least as useful as STIR images for illustrating anatomic structures and mass lesions, and in a much shorter scanning time. Separation of optic nerve from perioptic subarachnoid space was clear on SE images, but often difficult or impossible on STIR images owing to the relatively high intensity of normal optic nerves on STIR images. The synergism of relaxation prolongation with STIR actually resulted in loss of information, as any ability to separate the effects of T1 from T2 on signal intensity was impossible when STIR was the sole pulse sequence. We believe that more information is obtained with standard SE sequences than with STIR sequences, and therefore SE remains the method of choice for orbital MR imaging.     

STIR MR Imaging of the Orbit

Fifteen patients with CT-documented orbital lesions were evaluated with MR imaging at 1.5 T with both conventional spin-echo (SE) and short inversion time inversion recovery (STIR) sequences. Fat signal was reliably nulled at inversion times of approximately 120–200 msec in all cases, thereby allowing clear detection of all retrobulbar lesions and normal structures on STIR images as markedly hyperintense relative to fat. All lesions were also clearly depicted on SE images; in fact, short repetition time/short echo time SE sequences were at least as useful as STIR images for illustrating anatomic structures and mass lesions, and in a much shorter scanning time. Separation of optic nerve from perioptic subarachnoid space was clear on SE images, but often difficult or impossible on STIR images owing to the relatively high intensity of normal optic nerves on STIR images. The synergism of relaxation prolongation with STIR actually resulted in loss of information, as any ability to separate the effects of T1 from T2 on signal intensity was impossible when STIR was the sole pulse sequence.We believe that more information is obtained with standard SE sequences than with STIR sequences, and therefore SE remains the method of choice for orbital MR imaging.     

Common and Uncommon Artifacts in T1 FLAIR SAG Sequences of MRI Brain

ObjectiveThis study aims at identifying, classifying, and measuring the frequency the different artifacts that show up in the images of the Sagittal T1 Fluid Attenuated Inversion Recovery (FLAIR) sequence.Materials and MethodsA total of 101 subjects underwent brain magnetic resonance imaging examination with the following sequences: Axial T1 FLAIR, Axial T2-weighted imaging, Diffusion Weighted Imaging, 2D Multiple Echo Recombined Gradient Echo, Sagittal T1 FLAIR, Coronal T2 Turbo Spin Echo, Spin Echo T1-weighted imaging, and 3D Fast Spoiled Gradient-echo. In these images, we observed the following categories of artifacts: (a) ghost artifacts, (b) aliasing behind the occipital bone, (c) aliasing inside the sphenoid cavity, (d) susceptibility artifacts, and (e) pulsation artifacts. In order to recognize and verify the artifacts, we used not only the Sagittal T1 FLAIR sequence, but also Sagittal reconstructions from the 3-dimensional Fast Spoiled Gradient-echo sequence and the other routine sequences.ResultsAliasing artifacts and especially aliasing of nose are present in 41% of the cases. In 45% of these cases the uncommon aliasing artifacts, which took place into the brain parenchyma (sphenoid cavity, subarachnoid bay, or pituitary) originated from nose. In 33% of the subjects, ghost artifacts are presented, which stem from the nose, the orbits, or other pulsating structures (pulsation artifacts) or even from fat tissue. Moreover, susceptibility artifacts comprise 8% of all the artifacts. Finally, 19% of brains were presented without artifact.ConclusionsWe suggest in addition to T1 FLAIR, the application of Sagittal SE or TSE sequences in magnetic resonance imaging examination of brain, trying to include the nose in the square of FOV.     

MRI各序列诊断创伤性脑损伤的价值比较 MRI各序列诊断创伤性脑损伤的价值比较

目的：比较MRI各序列诊断创伤性脑损伤（traumatic brain injury,TBI）的价值.方法：对260例TBI患者行MRI序列组合扫描,包括FLASH、FLAIR、SE T1WI、TSE T2WI,分析不同类型TBI的影像特点,比较各序列对病灶的显示率.结果：260例中,FLASH显示244例（93.8％）,FLAIR显示249例（95.8％）,T2WI显示200例（76.9％）,T1WI显示199例（76.5％）,FLASH与FLAIR比较、T2WI与T1 WI比较,显示率差异均无统计学意义（P均＞0.05）;FLASH、FLAIR分别与T2WI、T1WI相比,显示率差异均有统计学意义（P均＜0.01）,FLASH、FLAIR对TBI病变的显示优于T2WI、T1WI.结论：MRI各序列显示TBI病灶总体敏感性由高至低依次为FLAIR、FLASH、T2WI、T1WI.FLAIR、FLASH应作为MRI诊断TBI的首选序列.     

T2 FLAIR增强扫描在颅内病变中价值的初步研究

目的探讨增强T2FLAIR在颅内病变诊断中的价值。方法58例资料完整并在增强T1WI或增强FLAIR上有强化的患者,确定增强T1WI和增强FLAIR上病变有无强化、强化的显著性、肿瘤性病变强化区的边界。结果3例脑梗塞在增强T1WI上未见强化,3例脑肿瘤在增强FLAIR上未见强化,1例脑膜瘤在增强FLAIR上呈负性强化;余51例中11例在增强FLAIR上强化更显著,16例在2个序列上强化相似,24例在T1WI上强化更显著。4例结核的脑膜病变范围和1例静脉窦血栓者回流受阻的皮层静脉在增强FLAIR上显示更加明确。结论增强T2FLAIR在颅内病变的诊断中有一定的价值,当增强T1WI显示不满意、怀疑脑膜或皮层血管病变时,应行增强T2FLAIR。     

MR imaging of intracranial epidermoid tumors: specific diagnosis with Turbo-FLAIR pulse sequence.

The purpose of this study is to present the imaging findings with particular reference to the FLAIR magnetic resonance (MR) pulse sequence, of four patients with epidermoid cysts. In all cases CT showed hypodense lesions with stippled peripheral calcifications and no enhancement. The MR showed low signal intensity lesions in T1-weighted images, high signal intensity in T2-weighted lesions, no or minor enhancement after gadolinium administration and characteristic heterogeneous appearance in FLAIR images. Including the FLAIR sequence in MR imaging, a specific diagnosis can be suggested.     

MR imaging for evaluation of severe facial nerve damage in patients with facial nerve palsy

PURPOSE: To evaluate the usefulness of MR imaging for the detection of severe facial nerve damage in patients with facial nerve palsy. MATERIALS AND METHODS: We retrospectively reviewed 26 consecutive patients with facial nerve palsy (13 non-responders and 13 responders). T1-weighted, T2-weighted, and postcontrast T1-weighted images were obtained in all patients. FLAIR images were also obtained in 3 non-responders. RESULTS: The geniculate ganglion, labyrinthine segment, and tympanic segment or mastoid segment showed high signal intensity on T2-weighted images in 9 of 13 non-responders, whereas high signal intensity of the nerve was only seen in 1 of 13 responders. FLAIR imaging revealed high signal intensity lesions of the distal intrameatal segment in 2 non-responders. Contrast enhancement of the facial nerve showed a similar pattern in non-responders and responders. High signal intensity lesions on T2-weighted or FLAIR images showed enhancement on postcontrast T1-weighted images. CONCLUSION: These results suggest that a high signal intensity area on T2-weighted images is a marker of severe facial nerve damage. FLAIR imaging is useful for identification of T2-prolongation in the distal intrameatal segment.     

Cortical lesions in multiple sclerosis: combined postmortem MR imaging and histopathology

BACKGROUND AND PURPOSE: Cortical lesions constitute a substantial part of the total lesion load in multiple sclerosis (MS) brain. They have been related to neuropsychological deficits, epilepsy, and depression. However, the proportion of purely cortical lesions visible on MR images is unknown. The aim of this study was to determine the proportion of intracortical and mixed gray matter (GM)-white matter (WM) lesions that can be visualized with postmortem MR imaging. METHODS: We studied 49 brain samples from nine cases of chronic MS. Tissue sections were matched to dual-echo T2-weighted spin-echo (T2SE) MR images. MS lesions were identified by means of myelin basic protein immunostaining, and lesions were classified as intracortical, mixed GM-WM, deep GM, or WM. Investigators blinded to the histopathologic results scored postmortem T2SE and 3D fluid-attenuated inversion recovery (FLAIR) images. RESULTS: Immunohistochemistry confirmed 70 WM, eight deep GM, 27 mixed GM-WM, and 63 purely cortical lesions. T2SE images depicted only 3% of the intracortical lesions, and 3D FLAIR imaging showed 5%. Mixed GM-WM lesions were most frequently detectable on T2SE and 3D FLAIR images (22% and 41%, respectively). T2SE imaging showed 13% of deep GM lesions versus 38% on 3D FLAIR. T2SE images depicted 63% of the WM lesions, whereas 3D FLAIR images depicted 71%. Even after side-by-side review of the MR imaging and histopathologic results, many of the intracortical lesions could not be identified retrospectively. CONCLUSION: In contrast to WM lesions and mixed GM-WM lesions, intracortical lesions remain largely undetected with current MR imaging resolution.