P型多系统萎缩的MRI表现

目的分析P型多系统萎缩(multiple system atrophy,MSA)的MRI特征,为临床诊断提供影像学依据。资料与方法回顾性分析经临床诊断为MSA-P型9例患者的常规MRI资料。结果 9例中,6例壳核有异常发现,其中壳核萎缩4例,壳核边缘长T2信号(裂隙征)2例,壳核弥漫性稍长T1、稍长T2信号3例,壳核后外侧极长T1、极短T2信号4例。6例中,单纯表现为壳核萎缩及壳核后外侧极长T1、极短T2信号各1例,余4例为多种壳核异常改变重叠出现。5例脑干有异常发现,其中"十字征"1例,全脑干萎缩4例;大脑半球异常5例,其中双额颞顶枕叶均萎缩3例,双额叶萎缩2例。小脑异常改变4例,其中2例小脑半球萎缩,2例小脑中脚对称性稍长T1、稍长T2信号。MSA-P型后期出现"十字征";液体衰减反转恢复(FLAIR)序列有利于发现异常信号。结论 MRI对于MSA-P型的临床诊断有重要意义。     

改变颈椎屈曲角度对平山病特异性MRI征象的影响

目的 比较平山病患者颈椎不同屈曲角度MRI表现,研究颈椎屈曲角度对平山病MRI征象的影响.方法 20例临床确诊为平山病的患者,行颈椎中立位及屈曲位20°、25°、30°、35°、40°MR扫描,观察不同屈曲位MRI硬脊膜前移、硬膜外间隙增宽2个征象出现率.并测量硬膜外间隙最大矢状径(d)及同水平椎管矢状径(D),计算d/D用于定量分析上述2个征象.不同屈曲位各征象出现率的比较使用Fisher精确概率法.各组间d/D平均值比较使用重复测量资料方差分析,之后对任意两组间d/D平均值进行比较.结果 患者颈椎背侧硬脊膜前移及硬膜外间隙增宽征象出现率在屈曲角度20°时为70%(14/20),25°以上均为100%,20°与25°时特殊征象出现率差异有统计学意义(χ2=5.760,P=0.020).20°、25°、30°、35°、40°时,对应d/D值分别为0.51±0.06、0.54±0.08、0.57±0.09、0.61±0.09、0.59±0.07,差异有统计学意义(F=3.450,P=0.013),两两比较提示d/D平均值在屈曲35°时>20°和25°,在屈曲40°时>20°(P值均<0.05).结论 颈椎屈曲角度可以影响颈椎背侧硬脊膜前移及硬膜外间隙增宽的MRI征象.     

平山病的MRI诊断

目的 探讨平山病低位颈髓在自然位和过屈位特殊的动态变化对诊断的价值。方法 对18例临床确诊为平山病的患者和31例正常对照者进行MR自然位和过屈位的矢状面和轴面扫描，测量C6椎体上缘颈髓前后径（APD）和横径（TD），观察其动态改变。结果 （1）自然位，平山病组表现有低位颈髓萎缩（病例组11例，对照组2例，X^2=14．76，P=0．000）和变扁平（病例组7例，对照组1例，X^2=8．15，P=0．004），差异有统计学意义。（2）过屈位，平山病组颈髓均前移后显著变扁，脊膜后有“月牙”形异常信号影。（3）自然位平山病组和对照组APD分别为（5．6±0．7）、（6．7±0．5）mm，过屈位APD分别为（4．3±0．8）、（6．0±0．5）mm，差异均有统计学意义（t值分别为-5．802、-8．952，P值均为0．000）。结论 平山病低位颈髓在正常位和过屈位存在特殊的动态变化，过屈位MRI可协助诊断。     

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。     

MRI和MR关节腔造影诊断肩袖撕裂的实验研究

目的 :探讨常规MRI和MR肩关节腔造影诊断肩袖撕裂的价值。方法 :采用 2 0个人离体肩关节标本 ,将常规MRI和追加MR肩关节腔造影检查结果与大体解剖、组织病理学结果进行比较。结果 :常规MRI检出肩袖部分撕裂的敏感度约为 61.9% ,追加MR肩关节腔造影后敏感度提高到 90 .5 %。常规MRI和MR关节腔造影检出肩袖完全撕裂的敏感度和特异度均为 10 0 %和 97.1%。结论 :在常规MRI检查的基础上追加MRI关节腔造影能提高检出肩袖部分撕裂的敏感度。     

MRI对肩袖撕裂的诊断价值

目的 评价肩关节MRI对肩袖撕裂的诊断价值,并分析其影像特征及损伤机制.方法 回顾性分析76例肩袖撕裂的MRI表现及临床症状.结果 肩袖全层撕裂共25例.其中冈上肌腱撕裂23例,同时向冈下肌腱延伸5例,6例合并肩胛下肌腱部分撕裂,1例合并肱二头肌长头腱断裂,2例合并关节盂前上盂唇撕脱.肩袖部分撕裂共51例,全部发生在冈上肌腱.其中上表面侧11例,下表面侧32例,肌腱内部分撕裂8例.其中8例同时在上表面及下表面发生部分撕裂,3例同时合并下表面及肌腱内部分撕裂.结论 肩关节MRI是评价肩袖撕裂比较有效的检查方法,为临床制定正确的治疗方案提供可靠的依据.     

Diagnosis of partial and complete rotator cuff tears using combined gradient echo and spin echo imaging

Most magnetic resonance (MR) studies evaluating the rotator cuff for tears have used T2-weighted imaging in the coronal oblique and sagittal oblique planes, T2^*-weighted gradient echo imaging, however, has advantages over spin echo imaging, including contiguous slices without cross-talk, high contrast around the cuff, and intrinsically shorter imaging times which can be used to increase the number of signals averaged and thus improve the signal-to-noise ratio. We reviewed the shoulder MR scans of 87 consecutive patients who underwent both a MR scan and a shoulder arthroscopy during which the size of tears, if present, was graded. The reviewers were blinded as to the history and arthroscopic results. The MR scans included oblique coronal T2^*-weighted gradient echo and oblique sagittal T2-weighted spin echo images. MR cuff grades were correlated with arthroscopic findings. For complete tears, the sensitivity of MR was 0.91 and the specificity 0.95. For partial tears, the sensitivity was 0.74 and the specificity 0.87. This accuracy is similar to two-plane T2-weighted imaging as previously reported in the literature. There was a statistically significant correlation (p < 0.0005) between the cuff grade as determined by MR and the arthroscopic findings.     

Rotator cuff disorders: How to write a surgically relevant magnetic resonance imaging report?

Evaluation of rotator cuff is a common indication for magnetic resonance imaging (MRI) scanning of the shoulder. Conventional MRI is the most commonly used technique, while magnetic resonance (MR) arthrography is reserved for certain cases. Rotator cuff disorders are thought to be caused by a combination of internal and external mechanisms. A well-structured MRI report should comment on the relevant anatomic structures including the acromial type and orientation, the presence of os acromiale, acromio-clavicular degenerative spurs and fluid in the subacromial subdeltoid bursa. In addition, specific injuries of the rotator cuff tendons and the condition of the long head of biceps should be accurately reported. The size and extent of tendon tears, tendon retraction and fatty degeneration or atrophy of the muscles are all essential components of a surgically relevant MRI report.     

The relationship of glenoid and humeral version with supraspinatus tendon tears

The aim of this study was to investigate the relationship of glenohumeral anatomic measurements on MR imaging with supraspinatus tendon tears. The study was approved by the institutional review board and informed consent was obtained from each subject. Forty-two patients (mean age 55.5 years; age range 40–73 years) with supraspinatus tendon tears and 50 asymptomatic shoulders of 32 controls (mean age 43 years; age range 17–69 years) without rotator cuff tears were included. The acromio-glenoid and supraspinatus-glenoid angles were measured on coronal images, the glenoid and humeral head version as well as the bicipital-humeral distance on axial images. Significant differences were found between the patients and controls for both glenoid version and bicipital-humeral distance, which are considered to influence the distribution of forces placed on the cuff (p < 0.05). The patients had a decreased glenoid version by an average of 2.3° (−7.1 ± 7.8° vs. −4.8 ± 5.6°), and a decreased bicipital-humeral distance by an average of 2.7 mm (12.1 ± 3.7 mm vs. 14.8 ± 4.1 mm). No significant differences were found between these groups for humeral head version and the acromio-glenoid and supraspinatus-glenoid angles, which might contribute to extrinsic impingement by narrowing the supraspinatus tendon outlet. Differences in glenoid and humeral version may be responsible for RC tears by changing the orientation of the rotator cuff and thus increasing shearing stress.     

Comparison of 3D turbo spin-echo SPACE sequences with conventional 2D MRI sequences to assess the shoulder joint

Purpose

To determine the accuracy and reliability of three-dimensional (3D) T1- and proton density (PD)-weighted turbo spin-echo (TSE) sampling perfection with application-optimized contrasts using different flip-angle evolution (SPACE) compared with conventional 2D sequences in assessment of the shoulder-joint.

Materials and methods

Ninety-three subjects were examined on a 3-T MRI system with both conventional 2D-TSE sequences in T1-, T2- and PD-weighting and 3D SPACE sequences in T1- and PD-weighting. All examinations were assessed independently by two reviewers for common pathologies of the shoulder-joint. Agreement between 2D- and 3D-sequences and inter-observer-agreement was evaluated using kappa-statistics.

Results

Using conventional 2D TSE sequences as standard of reference, sensitivity, specificity, and accuracy values of 3D SPACE were 81.8%, 95.1%, and 93.5% for injuries of the supraspinatus-tendon (SSP), 81.3%, 93.5%, and 91.4% for the cartilage layer and 82.4%, 98.5%, and 97.5% for the long biceps tendon. Concordance between 2D and 3D was almost perfect for tendinopathies of the SSP (κ = 0.85), osteoarthritis (κ = 1), luxation of the biceps tendon (κ = 1) and adjacent bone marrow (κ = 0.92). Inter-observer-agreement was generally higher for conventional 2D TSE sequences (κ, 0.23–1.0), when compared to 3D SPACE sequences (κ, −0.33 to 1.0) except for disorders of the long biceps tendon and supraspinatus tendon rupture.

Conclusion

Because of substantial and almost perfect concordance with conventional 2D TSE sequences for common shoulder pathologies, MRI examination-time can be reduced by nearly 40% (up to 11 min) using 3D-SPACE without loss of information.     

An assessment of the effectiveness of magnetic resonance imaging of the shoulder: literature review

Objective. To analyse and compare all papers published to date (August 2000) that quantify the effectiveness, defined as the impact of clinician’s diagnosis or management plans, or patient outcome, of MRI of the shoulder. Design. A computerised search of Index Medicus with a broad search strategy relating to shoulder MRI was performed. Manual assessment of all papers listed was undertaken with classification of each paper depending on whether it addressed questions of (1) technical performance, (2) diagnostic performance or (3) outcome. Results. Four of 265 qualifying papers addressed aspects of effectiveness and these were reviewed. The impact on the clinician’s diagnosis varied widely between papers: the primary diagnosis was altered in 23% to 68% of cases, and the management plans were subsequently changed in 15% to 61% of cases. Only one paper addressed the impact on patient health. Conclusions. The effectiveness of MRI of the shoulder depends on the clinical skills of the referring clinician and prevalence of disease in the study population. This will have implications when the effectiveness of an imaging technique between different institutions is compared, and this in turn will influence any comparisons of cost-effectiveness. Received: 22 October 1999 Revision requested: 31 January 2000 Revision received: 21 August 2000 Accepted: 24 August 2000     

头颈区去神经性肌萎缩的CT与MRI表现及其临床意义

本文报告８例头颈区去神经性肌萎缩的ＣＴ和ＭＲＩ表现，旨在评价其临床意义，引起肌萎缩的原因包括颈静脉孔区肿瘤４例（颈静脉球瘤，转移瘤各２例），鼻咽癌２例，中颅凹区脑膜瘤１例，上颌窦囊腺癌转移至咽旁１例，ＣＴ和ＭＲＩ表现为特定的颅神经运动支支配区肌肉轮廓缩小，脂肪间隙增宽，病程较长者表现为受累肌群完全为脂肪组织取代；３例根据肌萎缩征象发现原发病变。作者认为：认识去神经性肌萎缩的ＣＴ，ＭＲＩ表现可避免误     

MRI T2 mapping of the asymptomatic supraspinatus tendon by age and imaging plane using clinically relevant subregions

Purpose

Diagnosis of partial rotator cuff tears and tendonopathy using conventional MRI has proven variable. Quantitative T2 mapping may have application for assessing rotator cuff health. In order to evaluate the usefulness of T2 mapping for the rotator cuff, methods must be refined for mapping the supraspinatus tendon, and normative T2 values must first be acquired.

Materials and methods

This study was IRB approved. Thirty asymptomatic volunteers (age: 18–62) were evaluated with sagittal and coronal T2 mapping sequences. Manual segmentation of tendon and muscle as a unit and tendon alone was performed twice by two independent raters. Segmentations were divided into medial, middle and lateral subregions and mean T2 values calculated.

Results

Anatomic comparison of mean T2 values illustrated highest values in the medial region, lowest values in the lateral region, and intermediate values for the middle region upon coronal segmentation (p < 0.001). In sagittal segmentations, there were higher values in the medial region and no significant differences between the lateral and middle subregions. No significant differences were found with comparison across age groups. Inter and intra-rater segmentation repeatability was excellent, with coefficients ranging from 0.85 to 0.99.

Conclusion

T2 mapping illustrated anatomic variation along the supraspinatus muscle-tendon unit with low standard deviations and excellent repeatability, suggesting that changes in structure due to degeneration or changes associated with healing after repair may be detectable.     

Indirect MR arthrography of the shoulder in detection of rotator cuff ruptures

The aim of this study was to compare the efficacy of indirect MR arthrography images obtained following intravenous contrast injection and conventional MR imaging in the diagnosis of rotator cuff tears. Twenty-four patients with clinically suspected rotator cuff disease were examined. Conventional MR images and post-contrast indirect MR arthrography images were obtained. All images were evaluated in a blinded fashion by two musculoskeletal radiologist. Results were than analyzed depending on surgical output. The correlation coefficient (Spearman rank correlation test) and the kappa values for agreement between surgery and imaging techniques were calculated. The correlation coefficients between indirect MR arthrography and surgery for reader 1 and reader 2 were 0.9137 and 0.9773, respectively. Whereas the agreement between conventional MR imaging and surgery was moderate (ϰ = 0.383–0.571), the agreement between indirect MR arthrography and surgery was excellent (ϰ = 0.873–0.936). We suggest the use of indirect MR arthrography technique when conventional MR images are equivocal in diagnosis of rotator cuff disease. Received: 12 April 2000/Revised: 22 May 2000/Accepted: 23 May 2000     

Ultrasonography of symptomatic rotator cuff tears compared with MR imaging and surgery

Purpose

To compare the accuracy of ultrasonography and magnetic resonance imaging in the detection of rotator cuff tears.

Materials and methods

Ninety-six patients with clinically suspected rotator cuff pathology underwent ultrasonography and magnetic resonance imaging of the shoulder. The findings in 88 patients were compared with arthroscopy or open surgery.

Results

Full-thickness tear was confirmed in 57 cases, partial-thickness tear in 30 cases and degenerative changes without tear in 1. In all 57 cases of full-thickness tear and in 28 out of 30 cases of partial-thickness tear the supraspinatus tendon was involved. The accuracy in the detection of full-thickness tears was 98 and 100% for ultrasonography and magnetic resonance imaging, respectively. The accuracy in the detection of bursal or articular partial-thickness tears was 87 and 90% for ultrasonography and magnetic resonance imaging, respectively.

Conclusions

In experienced hands ultrasonography should be considered as an accurate modality for the initial investigation of rotator cuff, especially supraspinatus, tears.     

慢性肩袖病变的MR特点——大体解剖和组织学对照研究

目的:与大体解剖和组织学对照,探讨慢性肩袖损伤的MR影像特点。材料和方法:采用Philips Gy- roscant 1.0-NT磁共振扫描仪。对20只人离体肩关节标本进行MR成像。结果:肌腱变性表现为T_1W/ PDW信号增高,无明显形态改变。依据组织学结果,我们将慢性肌腱部分撕裂分为三型:典型撕裂口(Ⅰ型)表现为肌腱撕裂口T_2WI水样高信号;瘢痕型(Ⅱ型)信号表现多样,常表现为T_2序列稍高信号伴肌腱显著增粗,多见于慢性肩袖损伤;肌腱内撕裂(Ⅲ型)与肌腱变性难以区分。肌腱完全撕裂包括"隧道征"、宽大裂口伴或不伴肌腱断端退缩三种表现。结论:慢性肩袖损伤尤其是肩袖部分撕裂的MR表现较为复杂,必须将信号和形态特点相结合慎重诊断。     

Multiple sclerosis and corpus callosum atrophy: Relationship of MRI findings to clinical data

Summary Among 110 patients (45 men, 65 women), aged 15 to 66, with clinical and/or biological diagnosis of multiple sclerosis (MS), severe to moderate corpus callosum (CC) atrophy was observed in 67 (60%) patients. Correlation between CC atrophy, brain atrophy, duration and severity of clinical symptoms, and high signal white matter areas, was carried out in 90 patients. Mean age was 46 years for those with severe CC atrophy, and 33 years for those without atrophy. Mean duration of the disease was 14 years in patients with severe atrophy, and 5 years in patients without atrophy. Severity of clinical symptoms is more pronounced in patients with severe CC atrophy. Numerous or large white matter high signal areas are observed in patients with severe CC atrophy on T2-weighted images. CC atrophy appears earlier than brain atrophy in the course of MS.     

磁共振化学位移成像定量测量肩袖损伤后冈上肌脂肪性退变

目的：探讨MR化学位移成像技术在定量测量肩袖损伤后冈上肌脂肪性退变中的临床应用价值。方法：38例临床上疑有肩袖损伤或肩峰撞击的患者为研究对象,行MR间接关节造影后,进行常规序列和化学位移序列MRI扫描。根据MR间接关节造影检查结果,肩袖损伤后冈上肌肌腱病理改变可分为4组：正常组、肌腱炎组、部分撕裂组和完全撕裂组。通过测定冈上肌的信号强度,然后分别计算出信号强度抑制率和信号指数值作为反映脂肪变性程度的指标,对比分析正常组和肩袖损伤各组的冈上肌脂肪变性程度。统计学方法采用Wilcoxon秩和检验。结果：正常组、肌腱炎组、部分撕裂组和完全撕裂组冈上肌信号强度抑制率中位数分别是-5．51％（-7．85％～3．50％）、-14．78％（-29．31％～-5．63％）、-31．74％（-45．54％～-13．63％）和-44．50％（-57．32％～-26．27％）,信号强度指数中位数依次为3．91％（-4．37％～13．83％）、12．75％（5．73％～27．38％）、25．17％（14．32％～34．13％）和38．26％（27．66％～53．94％）。正常组与部分撕裂组、正常组与完全撕裂组、肌腱炎组与完全撕裂组间两两比较,差异有高度统计学意义（P〈0．01）;正常组与肌腱炎组、肌腱炎组与部分撕裂组、部分撕裂组与完全撕裂组间两两比较,差异有统计学意义（P〈0．05）。结论：MR化学位移成像技术是定量测定冈上肌脂肪性退变程度的-种有I临床应用价值的手段,有助于对肌腱病变进行分级并指导临床治疗。     

肩袖损伤的MR诊断进展

肩袖损伤是引起肩部疼痛和功能障碍的常见原因,可表现为全层撕裂或部分撕裂。MRI具有较高的软组织分辨力,可直接显示肩袖损伤部位及相关病理改变。本文复习肩袖的解剖结构,总结肩袖撕裂的MR诊断标准和主要表现及与X线平片、CT、B超相比的优越性、敏感性。研究表明,高场强MRI能更好地显示肌腱未受损部分与撕裂的对比,为临床制定正确的治疗方案提供帮助。