MR不同序列诊断早期脊柱转移瘤的价值

目的:探讨MR不同序列在诊断早期脊椎转移瘤中的价值.方法:25例临床怀疑脊柱转移瘤患者行脊柱磁共振检查,磁共振扫描序列包括自旋回波(SE)T1WI、快速自旋回波(TSE)序列T2WI、快速翻转恢复序列(STIR)、梯度回波(GRE)序列二维多回波聚合(Me-2D).结果:25例均发现脊柱转移瘤病灶,共73个椎体和45个附件受累.椎体的异常在各序列图像显示情况不同,T1WI显示73个异常椎体,T2WI显示55个,STIR显示69个,Me-2D显示73个.在T1WI序列图像有24个椎体表现为弥漫性异常信号,49个椎体局部信号异常.Me-2D序列显示椎体局部受累病灶边缘及骨小梁结构清晰.结论:SE T1WI,TSE T2WI及GRE Me-2D序列结合能够更敏感地发现椎体受累早期改变.     

磁共振胆胰管成像技术应用探讨

目的 评价磁共振胆胰管成像(MRCP)技术在诊断胆管疾病中的应用。方法 56例临床上怀疑胆管疾病患者均经MRCP技术检查。本研究使用GE Signa MR／i1．5T超导性磁共振成像设备和不同的技术序列，诸如二维快速自旋回波T2加权横断面扫描、二维自旋回波T1加权横断面扫描、SSFS序列冠状面扫描、多层薄层T2加权冠状面连续扫描、以及脂肪抑制与预饱和技术序列。结果 按照56例MRCP检查胆管的图像质量，满意者见于43例(76．8％)，欠满意者8例(14．3％)，以及不满意者5例(8．9％)。结论 MRCP在胆胰管疾病诊断中是一种具有较高敏感性、特异性和准确性的非侵袭性影像技术，临床用途广泛，尤其对用ERCP、PTC检查失败或不适合的病人，它堪称理想的替代方法。     

磁共振（MRI）技术在膝关节软骨损伤中的应用

目的：评估磁共振(MRI)不同扫描序列在膝关节软骨损伤中的应用价值。方法：选取临床上有外伤史，高度怀疑关节软骨损伤的患者38人40例膝关节进行MRI检查。MRI扫描序列包括：T1加权快速自旋回波序列(FSE—T1)质子和T2加权快速自旋双回波序列(FSE—PD／I2)、附加脂肪抑制的质子和T2加权快速自旋双回波序列(FS—FSE—PD/T2)、梯度回波T2加权序列(GRE)、附加脂肪抑制的三维快速扰相梯度回波序列(FS-3DT2^*-FSPGR)、反相位T1加权脂肪抑制序列(Unilatreal T1—Special—FSPGR)。结果：40例膝关节中30例做了关节镜检查，MRI诊断16例为软骨损伤，其中14例得到关节镜证实：MRI检查对关节软骨的诊断敏感度为87．5％，特异性为92％。各序列对软骨损伤的检出率从FSE—T1序列、FSE—PD/T2序列和GRE序列、到FS—FSE—PD／T2序列、Unilatreal T1—Special—FSPGR、FS-3DT2^*-FSPGR顺次增高，分别为25％、50％、80％、94％、100％。结论：MRI检查的几种序列都能清楚的显示膝关节软骨并对其损伤作出准确的诊断，其中FS—FSE—PD/T2序列，FS-3DT2^*-FSPGR序列、Unilatreal T1—Special—FSPGR较其他序列有无可比拟的优越性。     

磁共振尿路成像的技术和临床应用

一、目的：评估磁共振尿路成像的技术和临床应用价值。 二、资料和方法：用重T2加权快速自旋回波序列作MR尿路成像15例，其中12例经手术证实。所有图像均做最大信号强度投影（MIP）处理。     

低场磁共振T_1FLAIR序列在颅脑肿瘤诊断中的应用

目的 :通过T1FLAIR(液体反转恢复 )序列与传统SE(自旋回波 )序列T1加权图像对比分析 ,评价T1FLAIR作为T1成像序列对颅脑肿瘤的诊断价值。方法 :对 2 3例颅脑疾病患者均用两种序列检查。结果 :在 2 3例颅脑肿瘤中 ,T1FLAIR序列对病灶显示的图像清晰度比SE序列高。结论 :在相同病变检出率的情况下 ,T1FLAIR像在显示颅脑中灰白质对比度、病变和背景对比情况及病变的边界、大小、范围方面优于传统SE序列T1加权像 ,具有重要的临床诊断价值。     

肾上腺病变的磁共振诊断

目的探讨磁共振成像(MRI)对肾上腺腺瘤及增生的诊断价值。材料与方法经手术病理证实的34例肾上腺病变,其中腺瘤22例,增生10例,肾上腺节细胞神经瘤及嗜铬细胞瘤各1例,用低场强MR机,自旋回波序列,回顾性分析MRI征象。结果肾上腺腺瘤T1加权像呈中等信号占55%,T2加权像呈略高信号占77%。肾上腺增生T1加权像呈中等信号占60%,T2加权像中等信号占70%,略高信号占40%。MRI对肾上腺腺瘤的正确诊断率为96%,对肾上腺增生的正确诊断率为70%。结论MRI对肾上腺腺瘤的诊断准确性高,但有假阳性。T2加权像对肾上腺增生与腺瘤有一定鉴别意义,T1加权像无鉴别意义     

肠道磁共振水成像诊断肠梗阻的应用价值

目的:探讨利用肠梗阻肠腔内的液体行磁共振水成像对肠梗阻的诊断价值。方法:35例肠梗阻患者行磁共振水成像检查。行半傅里叶采集单次激发快速自旋回波(HASTE)序列T2WI冠状面扫描,快速自旋回波(TSE)序列T2WI冠状面扫描,以及真稳态进动快速成像(True-FISP)序列冠状面和横断面扫描,快速小角度激发成像(FLASH)序列横断面和冠状面平扫和增强扫描。将诊断结果与手术、病理结果或临床诊断对照。结果:恶性梗阻9例,手术病理证实6例;粘连性肠梗阻15例,手术证实8例,梗阻平面定位准确6例;肠扭转3例,手术证实2例。结论:肠道磁共振水成像判断肠梗阻的部位、病因、程度、性质具有较高准确性,是诊断肠梗阻的一种可靠方法。     

胎儿结肠三维磁共振成像研究

目的:探讨三维磁共振成像技术(3D-MRI)在显示胎儿结肠正常解剖和病变方面的临床应用价值.方法:对38例孕19～37周经超声诊断或怀疑胎儿畸形的孕妇在超声检查后1～2 d内进行MRI检查,使用单次激发快速自旋回波序列(SSFSE)行胎儿矢状面和冠状面常规扫描,三维快速扰相梯度回波序列(3D-FSPGR)行胎儿三雏磁共...     

小b值扩散加权成像对乳腺癌的诊断价值

目的:探讨小b值扩散加权成像(DWI)在诊断乳腺癌中的价值.方法:采用Philips 1.5T磁共振扫描仪对48例乳腺疾病患者行常规SE序列扫描、单次激发自旋回波-回波平面成像(SE-EPI)序列DWI及动态增强扫描.48例患者共检出53个病灶,其中良性肿瘤29个,恶性肿瘤24个,均经手术及病理证实;选择健康志愿者20...     

静脉对比增强在前列腺癌MRI的作用

作者将团注法对比增强提供的信息与标准的未增强的横断平面T_1和T_2加仪自旋回波像进行了对比,旨在评价团注静脉对比剂后动态成像对显示前列腺癌的作用。对象为20例前列腺癌病人,平均71岁(56～80岁),均经尿道切除或经直肠活检证实。按UICC TNM方法进行临床分期,结果为T_2期3例,T_3期14例,T_4期3例,多数为晚期前列腺癌。完成横断平面T_2加权和T_1加权自旋回波成像后,静脉团注钆剂(0.2ml/kg),再次作T_1加权序列,成像均在3.48分钟内获得。在动态系列完成后(开始注射后8分钟)用相同的T_1加权序列获取延迟增强成     

Prostatic carcinoma and benign prostatic hyperplasia: inability of MR imaging to distinguish between the two diseases

Forty patients with prostatic carcinoma or benign prostatic hyperplasia (BPH) underwent magnetic resonance (MR) imaging of the prostate. In vitro MR images of six prostate specimens were also obtained. The prostatic parenchyma was best evaluated by a T2-weighted spin-echo pulse sequence. The prostate both in patients with prostatic carcinoma and patients with BPH often had an inhomogeneous and nodular appearance on T2-weighted images. While most of the prostatic carcinomas appeared hyperintense relative to muscle and adjacent prostatic parenchyma, some of the hyperplastic nodules had a signal intensity similar to carcinoma. With current imaging techniques, MR imaging cannot differentiate prostatic carcinoma from BPH with certainty.     

Magnetic resonance tomography of prostatic cancer. A histopathologic correlation

A total of 52 patients with prostatic carcinoma were examined by MR imaging; 14 of them subsequently underwent radical prostatectomy and were included in this study. The resected prostates were sectioned axially and compared with the corresponding MR scans with special reference to the location and extent of the pathological changes. The prostatic carcinoma was visualized in 10 cases, but the size of the tumor was underestimated in 6 patients. In 9 of 10 patients the carcinoma was identifiable as an area of low signal intensity within the peripheral zone on T2-weighted images. The MR features of benign nodular hyperplasia are discussed.     

Seminal vesicles: biopsy-related hemorrhage simulating tumor invasion at endorectal MR imaging.

The diagnosis of seminal vesicle invasion by prostatic carcinoma is based on observation of foci of relatively decreased signal intensity on T2-weighted magnetic resonance (MR) images. Similar findings were observed in the absence of tumor invasion in nine patients who had recently undergone prostatic needle biopsy. Noncorresponding foci of abnormally increased signal intensity were also present on T1-weighted images in eight patients. These signal intensity abnormalities were of variable location and extent, and usually did not follow the expected pattern of spread from the primary prostatic tumor site. Radical prostatectomy in all patients showed the seminal vesicles to be normal. Signal intensity patterns observed on MR images appear to represent hemorrhagic breakdown products related to prostatic needle biopsy, which may result in direct trauma to the seminal vesicles. Another potential mechanism is retrograde transport of blood products from the site of prostatic biopsy to the seminal vesicles via the ejaculatory ducts. Awareness of this phenomenon will assist in accurate interpretation of MR images for staging of prostate cancer.     

Prostatic pathology imaged by magnetic resonance. 58 cases

Forty-eight patients with prostatic disease (benign prostatic hyperplasia (B.P.H.), carcinoma, cysts, myoma and prostatitis) and 10 normal volunteers underwent magnetic resonance imaging (M.R.I.) of the prostate. The prostatic parenchyma was best evaluated by a T2-weighted spin-echo pulse sequence. The prostate in patients with B.P.H. often had a homogeneous or more rarely a nodular appearance on T2-weighted images. In most cases, a peripheral dark rim is observed. All prostate in patients with carcinoma had an heterogeneous appearance on T2-weighted images. While most of the prostatic carcinomas appeared hypo-intense relative to adjacent prostatic parenchyma, some of the neoplasms had a high or mixed-high and low signal. The myoma showed a low-signal nodule like carcinoma. The cyst appears as a liquid tumor. The prostatitis had an homogeneous bright signal. With the used methodology, MRI can differentiate prostatic diseases in many cases. Nevertheless the technique has to be optimized to improve its accuracy.     

Prostatic carcinoma: staging by clinical assessment, CT, and MR imaging

The sensitivity, specificity, accuracy, and positive and negative predictive values of clinical assessment, computed tomography (CT), and magnetic resonance (MR) imaging were compared in the differentiation of stage B from stage C prostatic carcinoma. Forty-six patients who had undergone radical prostatectomy were included in the study. Surgical-pathologic staging was considered the "truth measure." Clinical staging had an accuracy of 61%, and CT, 65%. Accuracy for MR imaging depended on the instrument parameters and plane of section used. When only transverse T1-weighted images were analyzed, MR accuracy was 61%. However, when transverse T1- and T2-weighted images supplemented by additional T2-weighted coronal or sagittal images were studied, accuracy increased to 83%. At present, MR imaging is the most accurate diagnostic modality for the local staging of carcinoma of the prostate, but for optimal results, multiple sequences and two orthogonal planes of imaging are needed.     

Value of dynamic MR imaging in assessing endometrial carcinoma involvement of the cervix

OBJECTIVE: The purpose of this study was to evaluate endometrial carcinoma involvement of the cervix using dynamic MR imaging compared with T2-weighted and contrast-enhanced T1-weighted MR imaging. SUBJECTS AND METHODS: In 42 patients with endometrial carcinoma, T2-weighted MR imaging using rapid acquisition with relaxation enhancement, dynamic MR imaging using gradient-echo sequences, and contrast-enhanced T1-weighted MR imaging using spin-echo sequences were performed before treatment. We evaluated patterns of enhancement in the cervix and tumor. In 39 of the 42 patients who underwent surgical treatment, we compared MR imaging findings with histologic results concerning cervical involvement. RESULTS: Enhancement of the cervical epithelium was greater than that of the tumor and cervical stroma on dynamic MR imaging in most patients. In assessing cervical involvement, the accuracy of T2-weighted, dynamic, and contrast-enhanced T1-weighted MR imaging was 85%, 95%, and 90%, respectively; no statistically significant difference was observed. False-positive cases on T2-weighted MR imaging were correctly identified as having no cervical involvement on dynamic MR imaging using the finding of continuous enhancement of the cervical epithelium. We found this finding to be reliable in assessing tumor involvement of the cervix. CONCLUSION: We believe that, in combination with T2-weighted MR imaging sequences, dynamic MR imaging is useful in assessing endometrial carcinoma involvement of the cervix.     

Detection and characterization of metastatic cervical adenopathy by MR imaging: comparison of different MR techniques

Thirty-five patients scheduled to undergo a neck dissection for squamous cell carcinoma of the head and neck were evaluated preoperatively by magnetic resonance (MR) imaging. Axial and occasionally sagittal and coronal images were obtained. To define the most reliable technique to detect cervical lymph node metastasis, we compared several MR pulse sequences with and without Gd-DTPA administration to histopathologic findings in the neck dissection specimens. T1-weighted spin echo combined with T2-weighted gradient recalled echo (GE) sequences were found to be more useful than any other combination of pulse sequences in localizing lymph nodes. On T2-weighted GE images, lymph nodes were depicted with intermediate to high signal intensity in contrast to low signal muscular and fatty tissue. Gadolinium DTPA enhanced T1-weighted GE images reliably depict central lymph node necrosis, the most specific criterion for lymph node metastasis.     

MRI with an endorectal coil for staging of clinically localised prostate cancer prior to radical prostatectomy

The purpose of this study was to evaluate the ability of MR imaging with an endorectal coil (erMRI) to predict the local pathological stage of prostatic carcinoma prior to radical prostatectomy. Thirty-one consecutive patients (median age 61 years, range 40–71 years) with clinically localised prostate cancer were assessed preoperatively by endorectal MRI (at 1.0 T). The pulse sequences consisted of fast spin-echo axial and coronal T2-weighted images and inversion recovery with two echoes for axial fat-suppressed images. The assessment of tumour stage and measurement of tumour dimension by erMRI were compared with the corresponding findings on whole-mount step sections of the surgical specimens. Postoperatively, 14 of the 31 patients (45 %) were found to have extracapsular extension, 7 with capsular penetration (CP) only, and 7 had a combination of CP and seminal vesicle invasion (SVI). Capsular penetration was detected by erMRI with a sensitivity of 0.71 and specificity of 0.47, whereas the sensitivity for SVI detection was 0.71 and the specificity 0.83. Endorectal MRI for staging clinically localised prostatic carcinoma gives a good prediction of invasion of the seminal vesicles but is unreliable in predicting capsular penetration. Received: 25 November 1997; Revision received: 8 April 1998; Accepted: 8 May 1998     

Transurethral resection of the prostate-related changes in the prostate gland: correlation of MRI and histopathology

PURPOSE: The purpose of this work was to demonstrate signal changes of the prostatic urethra after transurethral resection of the prostate (TURP) on MR images and histopathologic correlation. METHOD: Sixty-three patients with prostate cancer confirmed by either TURP (Group A, 19 patients) or transrectal biopsy (Group B, 44 patients) were evaluated by endorectal MRI before radical prostatectomies. The MR images of postcurettaged prostatic urethras were correlated with the histopathologic features. RESULTS: On the T2-weighted images, a thin zone of hypointense signal surrounding the curettaged prostatic urethra was identified in 52.6% (10/19) of Group A patients, imaged soon after (mean 21.1 days) TURP, but was indiscernible in Group B patients and the other Group A patients, imaged later after TURP (mean 49.2 days). This hypointense signal zone histopathologically correlates with a zone of inflammatory tissue reaction surrounding the widened urethra. CONCLUSION: Inflammatory tissue reaction surrounding curettaged prostatic urethra after TURP accounts for the presence of a low signal zone on T2-weighted images.     

Prostatic MR imaging performed with the three-point Dixon technique. Work in progress

The three-point Dixon technique is an enhancement of the original Dixon method for the creation of water- and fat-proton magnetic resonance (MR) images. With the three-point Dixon technique, three measurements of phase shift at 0, pi, and -pi between the fat and water resonances are employed. Compensation for B0 inhomogeneity leads to an error-free decomposition into water- and fat-proton images; an accurate B0 map is also created. The lack of chemical shift artifact in the water- and fat-selective MR images permits the application of narrow receive bandwidth for the creation of T2-weighted images with a high signal-to-noise ratio. The technique was applied in vivo with four healthy subjects, seven patients with prostatic carcinoma, and one patient with benign prostatic hypertrophy and compared with conventional T2-weighted imaging. The three-point technique yielded images with improved definition of normal intraprostatic structures and zonal anatomy and, in some cases of prostatic carcinoma, provided better visualization of extraprostatic spread of tumor.