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1.
Unenhanced T1- and T2-weighted spin-echo, short inversion time inversion recovery (STIR), and gadolinium-DTPA (Gd-DTPA)-enhanced spin-echo and STIR imaging techniques were used in 20 patients as part of a multicenter study to assess the safety and efficacy of Gd-DTPA in spinal imaging. Five patients had normal MR scans. Of those with lesions, both Gd-DTPA-enhanced T1-weighted spin-echo and unenhanced STIR scans improved detection and evaluation of spinal tumors over conventional spin-echo methods, particularly T2-weighted spin echo, by providing higher tissue contrast in shorter imaging times. The Gd-DTPA-enhanced T1-weighted spin-echo scans were most helpful in evaluating intradural tumors, whereas STIR sequences were most effective for extradural tumors and bone metastases. In most cases, Gd-DTPA-enhanced T1-weighted spin-echo scans best delineated tumor margins, and the enhancement was helpful in suggesting a cellular or active nature of the lesions. In some cases, the enhancement resulted in a more homogeneous and thus less abnormal-appearing marrow in vertebrae involved by tumor; therefore, a precontrast T1-weighted spin-echo scan is necessary in all patients who are to be studied with Gd-DTPA.A combined approach that uses T1-weighted spin-echo, Gd-DTPA-enhanced T1-weighted spin-echo, and STIR images currently appears optimal for MR imaging of spinal neoplasms. T2-weighted spin-echo images add information only in occasional cases.  相似文献   

2.
Unenhanced T1- and T2-weighted spin-echo, short inversion time inversion recovery (STIR), and gadolinium-DTPA (Gd-DTPA)-enhanced spin-echo and STIR imaging techniques were used in 20 patients as part of a multicenter study to assess the safety and efficacy of Gd-DTPA in spinal imaging. Five patients had normal MR scans. Of those with lesions, both Gd-DTPA-enhanced T1-weighted spin-echo and unenhanced STIR scans improved detection and evaluation of spinal tumors over conventional spin-echo methods, particularly T2-weighted spin echo, by providing higher tissue contrast in shorter imaging times. The Gd-DTPA-enhanced T1-weighted spin-echo scans were most helpful in evaluating intradural tumors, whereas STIR sequences were most effective for extradural tumors and bone metastases. In most cases, Gd-DTPA-enhanced T1-weighted spin-echo scans best delineated tumor margins, and the enhancement was helpful in suggesting a cellular or active nature of the lesions. In some cases, the enhancement resulted in a more homogeneous and thus less abnormal-appearing marrow in vertebrae involved by tumor; therefore, a precontrast T1-weighted spin-echo scan is necessary in all patients who are to be studied with Gd-DTPA. A combined approach that uses T1-weighted spin-echo, Gd-DTPA-enhanced T1-weighted spin-echo, and STIR images currently appears optimal for MR imaging of spinal neoplasms. T2-weighted spin-echo images add information only in occasional cases.  相似文献   

3.
The objective of this study was to evaluate the appearance of localized giant cell tumour of the tendon sheath (GCTTS) on unenhanced and Gd-enhanced MR images. MR images of 13 histologically proven cases of localized GCTTS were evaluated for mean size, location, homogeneity and signal intensity (SI) on both T1- and T2-weighted images, and enhancement pattern. All lesions except 1 affected young adults. On T1- and T2-weighted images, lesions showed predominantly low SI equal to or slightly higher than skeletal muscle. On Gd-enhanced T1-weighted images, strong homogeneous enhancement was seen. These findings reflect the underlying histological composition of the lesion; haemosiderin deposition in xanthoma cells, shortening T2-relaxation time, and abundant collagenous proliferation are responsible for low SI on T1- and T2-weighted images. Strong homogeneous enhancement originates from numerous proliferative capillaries in the collagenous stroma. We conclude that these characteristic MR features, together with clinical information, are a valuable diagnostic tool in offering a correct preoperative diagnosis. Received 14 May 1996; Accepted 5 June 1996  相似文献   

4.
3.0 T MRI不同脉冲序列对胰腺疾病的诊断价值   总被引:2,自引:2,他引:0  
目的 探讨MRI检查不同脉冲序列对胰腺病变的诊断价值。方法 对87例临床怀疑胰腺病变的病人应用3.0 T MR设备进行检查,扫描序列包括双回波T1WI(同相位与反相位成像)、脂肪抑制T1WI(T1WI+FS)、脂肪抑制T2WI (T2WI+FS)、磁共振胆胰管水成像(MRCP)、快速多层面扰相梯度回波(FSPGR)动态增强扫描。由2名放射科医师分析不同脉冲序列的MRI所见。结果 正常胰腺15例,急性胰腺炎27例,慢性胰腺炎30例,胰腺癌15例。T1WI+FS显示胰腺形态与信号最佳,正常胰腺呈稍高信号。在双回波T1WI上,胰腺与周围组织对比度降低。胰腺病变在T1WI上表现为低信号50例,T2WI+FS显示胰周渗出性病变34例。MRCP显示胰管扩张35例,胆管扩张20例,双管征9例。快速扰相梯度回波(FSPGR)动态增强显示胰腺癌13例,肿块在动脉期表现为相对低信号,延迟期轻度强化,周围血管受侵2例。结论 合理应用MR扫描序列有助于提高胰腺病变的诊断效能。  相似文献   

5.
目的 探讨急性实验性变态反应性脑脊髓炎(EAE)模型的MRI表现及其病理基础.方法 用豚鼠全脑脊髓匀浆诱导EAE大鼠模型(6只),观察其体重变化和临床表现,同时设对照组(6只).在EAE大鼠发病后进行MR常规扫描、钆剂增强扫描,并静脉使用超小超顺磁性氧化铁(USPIO),24 h后行USPIO增强扫描,扫描完毕立即处死大鼠取脑,行脑组织切片的HE染色、髓鞘染色和普鲁士蓝染色.观察MRI和病理检查的异常所见,并进行对照.结果EAE大鼠组在诱导后第8~9天开始体重下降,在第10~11天出现临床症状.MR常规扫描未见明确异常,钆剂增强后仅见脑膜弥漫增厚及增强,USPIO增强扫描可见T2WI上延髓实质内大片低信号区,T1WI可见对应部位的高信号.梯度回波T2*WI比T2WI显示在脑干病灶以外的小脑白质内低信号.临床评分高的大鼠其低信号范围也较大.对照组大鼠未见异常.病理检查发现发病大鼠脑白质内散在血管套袖,部分伴相邻区域的脱髓鞘改变.普鲁士蓝染色发现病灶内巨噬细胞胞质内有蓝染颗粒,沉积部位与T2WI上低信号对应.结论USPIO增强MRI可以揭示常规MRI和钆剂增强成像未能显示的急性EAE病变,活体显示EAE病灶内巨噬细胞的分布,具有重要的研究价值和应用前景.  相似文献   

6.
目的 分析脑包虫病的MRI特征性表现.方法 回顾性分析18例经手术病理证实脑包虫病患者的MRI表现,总结脑包虫病的MRI诊断与鉴别诊断要点.结果 18例脑包虫病患者中囊性包虫病和泡型包虫病各9例.囊性包虫病表现为脑内大小不等的圆形长T1、长T2信号病灶,内部信号均匀一致,液体衰减反转回复(FLAIR)序列扫描其内囊液信号可被抑制;DWI序列病灶为低信号;6例病灶周围无水肿带,3例破裂包虫囊肿病灶周围有水肿带;6例病灶见囊壁显示,3例病灶囊壁显示不明显;增强扫描3例破裂包虫囊肿有环形强化,6例病灶无强化;泡型包虫病表现为脑内多发等T1、短T2簇状异常信号,病灶周围通常有类似脑肿瘤样的水肿带.病灶T2WI信号似"煤炭样"黑色的低信号,内见无数密集稍高信号的小囊泡影,小囊泡直径约1~10 mm为其特征性表现.DWI序列病灶为低信号;Gd-DTPA增强扫描后病灶均见不规则的异常环形强化.2例脑灌注成像病变为低灌注改变.结论 MRI以多方位、多参数成像的优势显示脑包虫更准确,术前诊断率更高,对临床诊治具有重要意义.  相似文献   

7.
The purpose of the study is to evaluate the ability of Gd-enhancement and fat-suppressed MR imaging operating at midfield strength to characterize incidentally discovered adrenal masses. Sixty patients with 72 adrenal masses incidentally discovered during US or CT exams were studied with a 0.51 MR unit following clinical and laboratory evaluation. After Gd-DTPA intravenous administration a modified three-point Dixon technique was performed in all patients. This technique provided three images sets: conventional T1-weighted SE images, fat-suppressed T1-weighted images and water-suppressed T1-weighted images. Diagnosis was established by means of surgery (11 lesions), fineneedle biopsy (21 lesions) and stability on ultrasonographic follow-up for at least 1 year (range, 12–87 months) from adrenal lesion discovery (40 masses). In most of adenomas (n = 55) an homogeneous enhancement was observed on postcontrast T1WI; however, 15 out of these lesions showed a small focal spot of high intensity in Gd-enhanced fat-suppressed images. On the contrary, malignant conditions (n = 6) and pheochromocytoma (n = 1), all had inhomogeneous signal intensities which were relatively higher after Gadolinium injection as compared with the liver. The fat suppression technique demonstrated areas of bright signal intensity related to high vascularity. The performance of three observers in order to differentiate malignant from benign conditions showed sensitivity, specificity, diagnostic accuracy, positive and negative predictive values of 100, 88.5, 90, 50 and 100% on the basis of gadolinium enhancement only, by utilizing the Dixon technique. In conclusion, although Gd-enhancement and fat-suppressed sequence helped correctly differentiate among the groups of incidentally discovered adrenal masses, the degree of overlap suggests that it is still difficult to characterize individual patients. However, the modified three-point Dixon technique after contrast material administration appears to be a further capability of midfield MRI in the characterization of adrenal tissue.  相似文献   

8.
肝脏炎性假瘤的CT及MRI征象   总被引:8,自引:0,他引:8       下载免费PDF全文
目的:探讨肝脏炎性假瘤的CT和MRI表现。方法:8例经手术病理证实的肝脏炎性假瘤。男5例,女3例,年龄35~65岁,平均53岁。8例均作CT平扫及增强扫描,其中3例行MR对比检查。结果:CT表现为1 个病灶6 例,2个病灶2例,共发现病灶10个。平扫9个病灶表现为低密度,1 个病灶表现为稍高密度。动态增强扫描2 个病灶动脉期显著强化,门脉期及延迟期中度强化;8个病灶动脉期无明显强化,门脉期及延迟期有不同方式的强化,主要表现为周边完整或不完整的环形或结节状强化,中心核心样强化及线状或不规则分隔样强化。MRI表现为2 例病灶T1WI呈低信号,T2WI呈稍高信号,1例病灶T1WI及T2WI均为等信号,动态增强扫描与CT相仿。结论:肝脏炎性假瘤的CT及MRI表现因其病理阶段不同而表现各异,诊断需结合临床,确诊尚依靠病理检查。  相似文献   

9.
Plain and Gd-DTPA-enhanced MR images of the brain were obtained in 18 consecutive patients with meningitis (eight with tuberculous, five with bacterial, three with viral, and two with fungal infections); the MR images were compared with CT scans. MR images were obtained on a 2.0-T superconducting unit with both T1- and T2-weighted pulse sequences before injection and with a T1-weighted sequence after injection of Gd-DTPA (0.1 mmol/kg) in all patients. In tuberculous meningitis, MR imaging depicted ischemia/infarct, hemorrhagic infarct of basal ganglia, meningeal enhancement at either basal cistern or convexity surface of brain, and associated small granulomas in a few more patients than CT did. In bacterial meningitis, primary foci of extracranial inflammation (i.e., mastoid, paranasal sinuses) and adjacent intracranial lesions including localized dural inflammation, subdural fluid collection, and/or brain parenchymal lesions were demonstrated much better on MR than on CT. Otherwise, MR images generally matched the CT scan. Although the plain MR images, both T1- and T2-weighted, were the most sensitive in delineating ischemia/infarct, hemorrhage, and edema, they were not as specific as Gd-DTPA-enhanced T1-weighted images and postcontrast CT scans in defining the active inflammatory process of the meninges and focal lesions precisely. We conclude that if Gd-DTPA is used, MR imaging appears to be superior to CT in the evaluation of patients with suspected meningitis. Precontrast MR is needed to delineate ischemia/infarct, edema, and subacute hemorrhage.  相似文献   

10.
Plain and Gd-DTPA-enhanced MR images of the brain were obtained in 18 consecutive patients with meningitis (eight with tuberculous, five with bacterial, three with viral, and two with fungal infections); the MR images were compared with CT scans. MR images were obtained on a 2.0-T superconducting unit with both T1- and T2-weighted pulse sequences before injection and with a T1-weighted sequence after injection of Gd-DTPA (0.1 mmol/kg) in all patients. In tuberculous meningitis, MR imaging depicted ischemia/infarct, hemorrhagic infarct of basal ganglia, meningeal enhancement at either basal cistern or convexity surface of brain, and associated small granulomas in a few more patients than CT did. In bacterial meningitis, primary foci of extracranial inflammation (i.e., mastoid, paranasal sinuses) and adjacent intracranial lesions including localized dural inflammation, subdural fluid collection, and/or brain parenchymal lesions were demonstrated much better on MR than on CT. Otherwise, MR images generally matched the CT scan. Although the plain MR images, both T1- and T2-weighted, were the most sensitive in delineating ischemia/infarct, hemorrhage, and edema, they were not as specific as Gd-DTPA-enhanced T1-weighted images and postcontrast CT scans in defining the active inflammatory process of the meninges and focal lesions precisely. We conclude that if Gd-DTPA is used, MR imaging appears to be superior to CT in the evaluation of patients with suspected meningitis. Precontrast MR is needed to delineate ischemia/infarct, edema, and subacute hemorrhage.  相似文献   

11.
Park BK  Kim B  Park JM  Ryu JA  Kim MS  Bae DS  Ahn GH 《European radiology》2006,16(7):1591-1598
The objectives of this study were to determine the usefulness of magnetic resonance (MR) imaging in the differentiation of various lesions causing an abnormality of the endometrial cavity by evaluating the imaging features on dynamic contrast-enhanced study and late contrast-enhanced T1-weighted images (T1WI). Contrast-enhanced MR imaging of 59 pathologically proven lesions that showed an abnormality of the endometrial cavity, including 32 endometrial cancers, five sarcomas, nine hyperplastic polyps, nine submucosal myomas, three hyperplasia, and one adenomyoma, were retrospectively reviewed. The enhancement degree and patterns on dynamic contrast-enhanced study and late contrast-enhanced T1WI were compared among different pathologies. On dynamic contrast-enhanced study, 72% (23/32) of endometrial cancers showed early peak enhancement to be reached within 1 min following intravenous administration of contrast material. On late-contrast-enhanced T1WI, lesions showed weak enhancement with gradual washout. Ninety-five percent (21/22) of benign lesions and 100% (5/5) of sarcomas showed late peak enhancement to be reached in 2–3 min following intravenous administration of contrast material. On late contrast-enhanced T1WI, both of these lesions showed persistent strong enhancement. Different enhancement patterns on dynamic contrast-enhanced MR imaging and late contrast-enhanced T1WI can provide a useful clue in the differentiation of various lesions causing an abnormality of the endometrial cavity.  相似文献   

12.
We assessed the fibrovascular ingrowth into porous orbital implant with MRI. Twelve cases underwent T1WI, T2WI, Gd-enhanced T1WI, and Short Tau Inversion Recovery (STIR) images. Gd-enhanced T1WI showed homogeneous enhancement (n=4), peripheral and posterior part enhancement (n=7), and anterior part enhancement (n=1) of implants. High signal intensity portions on STIR images coincided with the enhancing portions on Gd-enhanced T1WI. Gd-enhanced T1WI is an excellent method for assessment of fibrovascular ingrowth into orbital implant and STIR images may be a comparable method to Gd-enhanced T1WI.  相似文献   

13.
MR增强后液体衰减反转恢复序列对脑转移瘤的诊断价值   总被引:4,自引:1,他引:3  
目的 分析MR增强后液体衰减反转恢复(fluid attenuated inversion recovery,FLAIR)序列对脑转移瘤的诊断价值. 资料与方法 确诊恶性肿瘤可疑有脑转移患者159例.MR检查除常规平扫和增强外,在增强后加扫FLAIR序列,图像由3名有经验的放射科医师评估. 结果 58例有脑内转移,6例增强后FLAIR脑实质病灶数目显示较增强T1WI多,11例病灶强化较T1WI明显;在11例柔脑膜转移者中,7例病灶强化程度优于增强后T1WI. 结论 增强后FLAIR是增强后T1WI的有效补充,对脑内小病灶和脑膜病灶更敏感.  相似文献   

14.
To better understand the morphologic appearance of avascular necrosis (AVN) of the femoral head on magnetic resonance (MR) images (1.5 T) and computed tomographic (CT) scans, the records of 21 lesions were reviewed retrospectively. All MR imaging studies included T1-weighted images (T1WI) (repetition times [TR] of 400-1,000 msec, and echo times [TE] of 20-25 msec), and 15 included T2-weighted images (T2WI) (TR = 2,000-2,500 msec; TE = 60-80 msec). MR signal features of the lesions were compared with features on the corresponding CT scans. Abnormalities in the superoanterior aspect of the femoral head were noted on both image types in all 21 lesions but were more obvious on MR images in two. A characteristic margin of peripheral sclerosis seen on CT scans in 95% (20 of 21) of lesions corresponded to a line of low intensity on MR images. Fractures complicating AVN were seen in eight lesions at CT scanning. On T1WI, fractures were not clearly delineated. On T2WI, fractures were of high intensity but were depicted less clearly than on CT scans. Central signal intensity of the lesions on T1WI correlated with the presence or absence of fracture: 88% (seven of eight) of the lesions with fractures appeared less intense than fat, compared with only 8% (one of 13) of lesions without fractures (P less than .005). While MR imaging is a sensitive method for early diagnosis of AVN, CT scanning can more accurately identify fractures and is thus important for staging.  相似文献   

15.
脊髓多发性硬化的MRI诊断与鉴别诊断   总被引:6,自引:0,他引:6  
目的 提高对脊髓多发性硬化MRI特征的认识。方法 对 15例脊髓多发性硬化患者行颈部MRI检查。对病变的位置、长度、横断面上病变大小及病变的强化进行评价 ,并与脊髓内肿瘤、脊髓型颈椎病、急性横贯性脊髓炎的MRI表现进行比较。结果  15例脊髓多发性硬化主要发生在颈段脊髓 ,病变一般少于 5个椎体长度 ,MRI特点为矢状位脊髓局限性梭形增粗 ,边缘光滑。T1WI呈等或界限模糊的稍低信号 ,T2 WI呈长短不一的条形高信号。轴位像病灶位于脊髓侧方和后方 ,一般小于脊髓截面 1/2。活动期病灶呈条、片状强化 ,但强化区范围明显小于T2 高信号灶范围。反复发作病例多发病灶强化多样性 ,也可不强化。结论 脊髓多发性硬化有其特征性MRI表现 ,能为临床诊断提供可靠的依据  相似文献   

16.
颅内巨大动脉瘤的CT与MR诊断   总被引:3,自引:0,他引:3  
目的:探讨CT和MR对颅内巨大动脉瘤的诊断价值。方法:8 例颅内巨大动脉瘤病人进行了CT和MR检查,并经血管造影和手术证实。其中,男4 例,女4 例,年龄34~72岁,平均54岁。临床上5例表现为颅内占位症状,3例为蛛网膜下腔出血症状。结果:5例动脉瘤起源于颈内动脉,2 例起源于大脑中动脉,1例起源于椎基底动脉。CT和MR表现如下:(1)CT平扫病灶呈稍高密度圆形阴影,密度可均匀或不均匀,增强扫描病灶明显强化。(2)MR扫描显示残存瘤腔在T1WI及T2WI上均呈无信号区,周围为混合信号带。该信号带在T1WI上信号稍高于脑灰质,在T2WI上则稍低于脑灰质。增强扫描部分病例动脉瘤壁及混合信号带有强化表现。(3)动脉瘤破裂时,CT与MR可显示相应出血表现。结论:对颅内巨大动脉瘤的诊断,MR优于CT,尤其在显示瘤腔和血栓方面MR有独到之处  相似文献   

17.
增强FLAIR序列在颅脑病变中的应用   总被引:1,自引:0,他引:1  
目的评价增强FLAIR序列在颅脑疾病诊断中的应用.材料与方法50例患者行脑MRI平扫(T1 WI、T2 WI、FLAIR)和Gd-DTPA增强(FLAIR和T1WI)检查,双盲法比较增强前后FLAIR与T1 WI的差异.结果所有病变在FALIR均显示不同程度的异常增强,在脑梗塞疾病中增强FLAIR诊断敏感性大于增强T1 WI.星形细胞瘤、转移瘤和结核瘤,T1 WI增强优于FLAIR.结论增强FLAIR在检查脑表面病变,如皮质或皮质下梗塞,诊断准确性高于增强T1 WI.  相似文献   

18.
Objective. To determine the usefulness of fat-suppressed gadolinium (Gd)-enhanced MR imaging of the wrist in patients with rheumatoid arthritis (RA). Design and patients. Fat-suppressed Gd-enhanced T1-weighted spin-echo (SE) images were obtained and compared with other standard techniques in 38 wrists of 27 patients (22–77 years) with RA. Scoring based on the degree of synovial enhancement of each joint was developed and the total scores (J-score) were correlated with radiographic stage, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and symptomatic change in the follow-up study. Results. Synovial proliferations showed marked enhancement in all the wrists. In addition, contrast enhancement in the bone marrow and tenosynovium was seen in 36 and eight wrists respectively. Fat-suppressed Gd-enhanced T1-weighted images demonstrated these abnormalities better than other techniques. The J-scores correlated well with values of CRP (P=0.0034), but not with radiographic stages and ESR. Conclusion. Fat-suppressed Gd-enhanced T1-weighted SE images can clearly demonstrate most of the essential lesions in RA including the proliferative synovium, bone erosion, bone marrow inflammatory change, and tenosynovitis. Scoring based on the extent of Gd-enhancement of synovium can be useful in the assessment of the inflammatory status.  相似文献   

19.
In an attempt to differentiate among joint effusion, synovitis, pannus, and subchondral sclerosis in patients with clinically proved chronic rheumatoid arthritis, we used gadopentetate dimeglumine-enhanced MR imaging to examine 23 patients with acute knee symptoms. All patients had had rheumatoid arthritis for more than 6 months and satisfied four or more of the criteria of the American Rheumatism Association for rheumatoid arthritis. MR imaging was performed on a 1.5-T machine by using unenhanced T1-weighted spin-echo imaging, unenhanced T2*-weighted gradient-echo imaging, and unenhanced and enhanced T1-weighted gradient-echo imaging. Signal intensities of the synovium and bone marrow were measured with the region-of-interest technique on unenhanced and enhanced T1-weighted gradient-echo scans. Conventional radiographs were available for each patient. Joint effusion, synovitis, intraarticular pannus, subchondral sclerosis, and subchondral pannus had the same signal intensities on unenhanced T1-weighted spin-echo, unenhanced T1-weighted gradient-echo, and unenhanced T2*-weighted gradient-echo MR images, and could not be differentiated from one another. On enhanced T1-weighted gradient-echo sequences, pannus and synovitis showed marked enhancement in 15 patients, whereas joint effusion and sclerosis did not. Synovitis was diagnosed if the synovial membrane showed high enhancement; pannus was diagnosed if enhancing masses were seen within the joint space or in the subchondral area. In eight of the 23 joints, there was no enhancement of the synovium or intraarticular or subchondral tissue. We conclude that gadopentetate dimeglumine-enhanced MR imaging allows differentiation between synovitis and joint effusion and between subchondral pannus and subchondral sclerosis. Enhancement of the synovium and pannus indicates acute inflammation of the joint.  相似文献   

20.
MR brain scans, spinal fluid electrophoresis, and evoked responses were obtained in 10 adult patients with isolated spinal cord symptoms diagnosed as possible multiple sclerosis (MS) according to the McAlpine criteria. Typical lesions of MS were found on T2-weighted MR images in six patients. Spinal fluid abnormalities were found in four. Visual-evoked responses or brainstem auditory-evoked responses were abnormal in three. MR in conjunction with spinal fluid analysis supported the diagnosis of MS in eight of 10 patients. Evoked responses appeared less sensitive than MR in identifying subclinical lesions in this population.  相似文献   

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