The rheumatoid cervical spine: signs of instability on plain cervical radiographs

The cervical spine is a common focus of destruction from rheumatoid arthritis, second only to the metacarpophalangeal joints. Joint, bone and ligament damage in the cervical spine leads to subluxations which can cause cervical cord compression resulting in paralysis and even sudden death. Because many patients with significant subluxations are asymptomatic, the radiologist plays a key role in recognizing the clinically important clues to instability on plain radiographs of the cervical spine-often difficult in rheumatoid arthritis when the bony landmarks are osteoporotic or eroded. This review focuses on the signs of instability on plain radiographs of the cervical spine, using diagrams and clinical examples to illustrate methods of identifying significant subluxations in rheumatoid arthritis.     

A Pictorial Review of Atlanto-axial Rotatory Fixation: Key Points for the Radiologist

Atlanto-axial rotatory fixation (AARF) is a rare condition which occurs more commonly in children than in adults. The terminology can be confusing and the condition is also known as 'atlanto-axial rotatory subluxation' and 'atlanto-axial rotary dislocation'. Rotatory fixation is the preferred term, however, as in most cases the fixation occurs within the normal range of rotation of the joint. By definition, therefore, the joint is neither subluxed nor dislocated. AARF is a cause of acquired torticollis. Diagnosis can be difficult and is often delayed. The radiologist plays a key role in confirming the diagnosis. The classification system proposed by Fielding in 1977 is most frequently used and will be discussed in detail. Given that this classification system was devised in the days before computed tomography (CT), as well as the fact that combined atlanto-axial and atlanto-occipital rotatory subluxation (AORF) is omitted from the classification, we propose a modification to the classification of this rare but significant disorder. The radiological findings in six cases of AARF will be illustrated, including a case with associated atlanto-occipital subluxation. The pertinent literature is reviewed and a more comprehensive classification system proposed. The imaging approach to diagnosis and the orthopaedic approach to management will be discussed.     

经口咽前入路寰枢椎手术的解剖学研究

目的　为经口咽前入路处理寰枢椎腹侧病变提供解剖学依据。方法　对 10例新鲜的成人头颈部标本经口咽前入路进行逐层的显微外科解剖 ,观察咽后壁的层次、椎动脉的走行、寰枢椎的解剖毗邻关系和寰枢椎前路钢板内固定的相关解剖参数等。结果　咽后壁分两层(黏膜层、椎前筋膜层)和两个间隙 (咽后间隙、椎前间隙 ) ;经口咽前入路可显露从枕骨大孔前缘至C3 椎体的范围 ;椎动脉距寰椎和枢椎中线的距离分别为 2 5 2± 2 3mm(2 0 4～ 2 9 7mm)和 18 4± 2 6mm(13 1～ 2 3 0mm) ;寰椎和枢椎可显露宽度分别为 39 4±2 2mm(36 2～ 4 2 7mm)和 39 0± 2 1mm(35 8～ 4 2 3mm) ,寰椎进钉点 (侧块中点 )间距 (a)为 31 4± 3 3mm(2 5 4～ 36 6mm) ,寰椎进钉点连线与枢椎进钉点 (椎体中线旁开 3～4mm)连线的垂直间距 (b)为 18 7± 2 7mm(14 9～ 2 3 2mm) ,a/b比值为 1 5～ 1 7。结论　经口咽前入路寰枢椎手术是安全可行的 ,适合做寰枢椎前路钢板内固定 ,钢板的设计应以上述测量数据为依据     

Imaging of Herniated Discs of the Cervical Spine: Inter-Modality Differences between 64-Slice Multidetector CT and 1.5-T MRI

ObjectiveTo assess inter-modality variability when evaluating cervical intervertebral disc herniation using 64-slice multidetector-row computed tomography (MDCT) and magnetic resonance imaging (MRI).ResultsThe interobserver agreement rates upon evaluation of disc morphology by the three radiologists were in fair to moderate agreement (k = 0.39-0.53 for MDCT images; k = 0.45-0.56 for MRIs). When the disc morphology was categorized into two and four grades, the inter-modality agreement rates were moderate (k-value, 0.59) and substantial (k-value, 0.66), respectively. The inter-modality agreements for evaluations of the NIS (k-value, 0.78) and the epicenter (k-value, 0.79) were substantial. Also, the interobserver agreements for the NIS (CT; k-value, 0.85 and MRI; k-value, 0.88) and epicenter (CT; k-value, 0.74 and MRI; k-value, 0.70) evaluations by two readers were substantial. MDCT tended to underestimate the extent of herniated disc lesions compared with MRI.ConclusionMultidetector-row computed tomography and MRI showed a moderate-to-substantial degree of inter-modality agreement for the assessment of herniated cervical discs. MDCT images have a tendency to underestimate the anterior/posterior extent of the herniated disc compared with MRI.     

Quantification of C2 cervical spine rotatory fixation by X-ray,MRI and CT

Atlanto-axial rotatory displacement is known to be a cause of childhood torticollis and may as well be responsible for chronic neck pain after rear-end automobile collisions. The objective was to determine whether quantification of C2 malrotation is possible by plain radiographs in comparison to CT as the golden standard. MR imaging was evaluated as to whether it was of equal value in the detection of bony landmarks. C2 vertebra of five human cadaveric cervical spine specimens, ligamentously intact, were rotated using a Steinmann pin in steps of 5° up to 15° right and 15° left. Plain radiographs, CT and MRI images were taken in each rotational step. Data were analyzed for quantification of C2 rotation by three independent examiners. A rotation of 5° led to a spinous process deviation (SPD) from the midline of 3 mm as measured on an a.p. plain radiograph. A coefficient of rotation was calculated (1.62° mm^–1). Data analyzed by three examiners revealed a small coefficient of variation (0.03). MRI and CT measurements showed comparable results for the quantification of rotation; however, in both techniques the 15° rotation was underestimated. Quantification of upper cervical spine malrotation was possible on plain radiographs using the SPD and a rotation coefficient. MRI and CT were equally successful in the assessment of C2 malrotation.     

非外伤性脊髓硬膜外血肿的MR诊断

目的　探讨非外伤性脊髓硬膜外血肿的MR表现特点及其鉴别诊断。方法　 14例非外伤性脊髓硬膜外血肿 ,男 9例 ,女5例 ,年龄 4～ 63岁 ,平均 41.3岁。所有病例均无明显的外伤史。常规行T1W矢状位 ,T2 W矢状位及横切位扫描 ,1例行MR增强扫描。结果　 14例非外伤性脊髓硬膜外血肿中 11例位于椎管背侧 ,3例位于椎管腹侧 ,呈新月状或长条带状 ,分别累及 3～ 12个脊髓节段 ,平均 5 .2个脊髓节段。血肿位于颈胸段 4例 ,位于胸段 3例 ,位于胸腰段 5例 ,位于腰段 2例。 10例血肿T1W及T2 W均呈较均质性高信号强度 ,3例血肿T1W及T2 W呈不均质性高信号强度 ,1例于T1W呈中等信号强度 ,T2 W呈较低信号强度。 14例中 1例于血肿内可见低信号的血管流空影 ,术后证实为动静脉畸形。血肿于T1W及T2 W与脊髓之间有一低信号带相隔 ,尤以T2 W显示最佳。 2例受压脊髓于T2 W呈高信号。 1例行MR增强扫描 ,血肿壁轻度强化。结论　MR是诊断非外伤性脊髓硬膜外血肿的最佳检查方法 ,不仅可以清楚地显示血肿的部位及范围 ,而且可以清楚地显示血肿新旧程度及脊髓受损的情况     

脊柱结核的MRI表现

目的探讨脊柱结核的MRI表现特征。方法回顾性分析38例经手术病理证实的脊柱结核患者的MRI资料。结果(1)38例患者101个椎体受累,单椎体5例,2个椎体13例,3个椎体12例,4个椎体以上8例。T1WI呈均匀低信号37个,混杂低信号61个,等信号3个。T2WI及T2/SPIR呈均匀高信号34个,混杂高信号63个,等信号4个。增强扫描呈不均匀强化。(2)29例45个椎间盘受累,椎间隙狭窄27个,椎间隙消失18个。T1WI呈低信号,T2WI及T2/SPIR呈不均匀高信号。(3)27例寒性脓肿形成,其中25例为椎体前缘或周围脓肿,5例伴腰大肌脓肿,14例见椎管内脓肿。脓肿T1WI呈稍低信号,T2WI及T2/SPIR呈明显高信号,增强扫描呈不均匀强化或环形强化。(4)12例患者19个椎弓根受累;19例脊髓受压。结论脊柱结核病变具有多样性,病变可累及椎体的各部位,MRIT1WI及T2WI以混杂信号为主,综合分析有助于诊断和鉴别诊断。     

Retinoblastoma: CT and MRI

To evaluate the effectiveness of CT and MRI at 0.5 T in the diagnosis and staging of retinoblastoma, we studied 11 patients in whom retinoblastoma was clinically suspected. Nine of the eleven had surgically proven retinoblastoma; in the other two a diagnosis of Coat's disease was made. MRI was not as specific as CT for diagnosing retinoblastoma, due to its lack of sensitivity in detecting calcification; it did, however, have superior contrast resolution. On MRI, Coats' discase was reliably diagnosed and easily differentiated from retinoblastoma. Moreover, the greater ability of MRI to differentiate subretinal fluid from tumour also confers high accuracy in measuring tumour size. CT is still the study of choice in the diagnosis of retinoblastoma, but when MRI is available, it should be performed for better differentiation from lesions such as Coats' disease.     

Lumbosacral epidural lipomatosis: MRI grading

Lumbosacral epidural lipomatosis (LEL) is characterized by excessive deposition of epidural fat (EF). The purpose of our retrospective study was to quantify normal and pathologic amounts of EF in order to develop a reproducible MRI grading of LEL. In this study of 2528 patients (1095 men and 1433 women; age range 18–84 years, mean age 47.3 years) we performed a retrospective analysis of MRI exams. We obtained four linear measurements at the axial plane parallel and tangent to the superior end plate of S1 vertebral body: antero-posterior diameter of dural sac (A-Pd DuS), A-Pd of EF, located ventrally and dorsally to the DuS, and A-Pd of the spinal canal (Spi C). We calculated (a) DuS/EF index and (b) EF/Spi C index. We developed the following MRI grading of LEL: normal, grade 0: DuS/EF index ≥1.5, EF/Spi C index ≤40%; LEL grade I: DuS/EF index 1.49–1, EF/Spi C index 41–50% (mild EF overgrowth); LEL grade II: DuS/EF index 0.99–0.34, EF/Spi C index 51–74% (moderate EF overgrowth); LEL grade III: DuS/EF index ≤0.33, EF/Spi C index ≥75% (severe EF overgrowth). The MRI exams were evaluated independently by three readers. Intra- and interobserver reliabilities were obtained by calculating Kappa statistics. The MRI grading showed the following distribution: grade 0, 2003 patients (79.2%); LEL grade I, 308 patients (12.2%); LEL grade II, 165 patients (6.5%); and LEL grade III, 52 patients (2.1%). The kappa coefficients for intra- and interobserver agreement in a four-grade classification system were substantial to excellent: intraobserver, kappa range 0.79 [95% confidence interval (CI), 0.65–0.93] to 0.82 (95% CI, 0.70–0.95); interobserver, kappa range 0.76 (95% CI, 0.62–0.91) to 0.85 (95% CI, 0.73–0.97). In LEL grade I, there were no symptomatic cases due to fat hypertrophy. LEL grade II was symptomatic in only 24 cases (14.5%). In LEL grade III, all cases were symptomatic. A subgroup of 22 patients (42.3%) showed other substantial spinal pathologies (e.g., disk herniation). By means of simple reproducible measurements and indexes MRI grading enables a distinction between mild, moderate, and severe EF hypertrophy. Kappa statistics indicate that LEL can be reliably classified into a four-grade system by experienced observers.     

国人脑解剖结构的磁共振三维重建初探

目的：通过磁共振对国人脑进行三维重建以便清晰显示脑内解剖结构,以便建立脑部解剖的数字化图像。方法筛选25例中国中青年无脑部疾病的健康志愿者,利用1.5 T磁共振采集其脑部的影像数据,在计算机后处理工作站采用MATLAB、SPM及Mango等多种图像处理软件进行标准化和三维重建处理,以便立体显示脑深部解剖结构。结果采集的MRI脑图经过一系列校正处理后,对大脑皮质、髓质、脑室、基底核、脑干、小脑等主要结构进行提取并存入数据库,经过多步骤重建处理显示脑三维立体形态,在此基础上确定脑内三维坐标,再把解剖名称按一定顺序与脑部结构进行相应标注,从而通过多功能浏览器用鼠标点击不同层面的脑深部结构,即可实时显示其三维坐标及相应的中英文双语解剖名称,可进行交互式的操作,方便使用者浏览和学习脑部解剖。结论 MRI三维脑图谱对脑神经科学研究及教学具有重大意义,其在计算机辅助手术、影像指导手术及微创手术等领域起着很大作用。     

Mapping system for coregistration of cardiac MRI and ex vivo tissue sampling

Purpose:

To design a method suitable for obtaining tissue samples from regions of different function as ascertained by magnetic resonance imaging (MRI).

Materials and Methods:

In vivo MRI was used to create azimuthal projections of the heart from dilated cardiomyopathy transplant patients with the cardiac valves in the center and four concentric rings representing the septum and free wall. Tagged MRI could identify regions of different contractile strength that were then transferred onto the map projection. The resulting tissue sampling map was used to guide dissection of tissue samples from the explanted heart for analysis by electron microscopy (EM) as well as provide samples for subsequent mRNA analysis. Accuracy of the sampling was determined in a sheep heart using 17 fiduciary markers glued to the epicardial surface.

Results:

Tagged MRI identified areas of “normal” (%S_c ?11), “poor” (%S_c ?4) and “failed” contraction (%S_c +3). The mapping method we developed enabled straightforward sampling of these regions after surgical excision. EM showed good tissue preservation while the test of accuracy using the fiduciary markers showed a sampling accuracy of 0.3 ± 3.7 mm. This was similar to the resolution of tagged MRI images themselves.

Conclusion:

The methods we have developed can accurately guide tissue sampling for ex vivo tissue analysis. J. Magn. Reson. Imaging 2011. © 2011 Wiley Periodicals, Inc.

     

Radiography,abdominal CT and MRI compared with sacroiliac joint CT in diagnosis of structural sacroiliitis

ObjectiveTo assess the performance of pelvic plain radiograph (radiography), abdominal CT and sacroiliac joint MRI (MRI) compared with sacroiliac joints CT (SI joint CT) for the diagnosis of structural sacroiliitis in a population suffering from spondyloarthritis (SpA) meeting the New York or ASAS criteria.MethodsAll SpA patients eligible for biologic treatment who received a pre-therapeutic check-up including the four imaging techniques in the same year were selected from 2005 to 2012. An assessment of sacroiliitis was based independently by a rheumatologist and a radiologist on radiography according to the modified New York criteria and on abdominal CT, MRI and SI Joint CT depending on the presence of erosion on at least two consecutive slices. A final diagnosis was established for conflicting exams.ResultsOf the 58 selected patients, sacroiliitis was diagnosed on radiography, abdominal CT, MRI and SI Joint CT in 32, 26, 34 and 35 patients, respectively. Inter-reader agreements for the grade of sacroiliitis were substantial with a weighted Kappa that varied between 0.60 and 0.76 and they were moderate for the diagnosis of sacroiliitis with a Kappa that varied between 0.45 and 0.55 for the four imaging modalities. The sensitivities of radiography, abdominal CT and MRI were 82.8%, 71.4% and 85.7% respectively and the specificities were 86.9%, 100% and 82.6% respectively with excellent accuracy and positive predictive value and good negative predictive value.ConclusionThis study demonstrates the relevance of MRI and abdominal CT for the diagnosis of structural sacroiliitis with good sensitivities and excellent specificities. These imaging modalities may also contribute for the diagnosis of structural sacroiliitis.     

多发性骨髓瘤MRI表现与骨髓瘤细胞比值关系研究

目的　探讨多发性骨髓瘤(multiplemyeloma, MM)MRI表现与骨髓瘤细胞比值的关系。方法　对经骨髓涂片或活检确诊的 15例MM病人的脊柱MRI表现分型,分析各型与骨髓瘤细胞所占百分比、血红蛋白值的关系。结果　局灶型病变 7例,弥漫型 4例,“盐和胡椒面”型 4例。MRI表现分型不同,骨髓瘤细胞所占百分比值之间存在显著性差异 (Ρ=0. 008);血红蛋白值之间亦存在显著性差异(Ρ= 0. 03)。MM的脊柱弥漫型侵犯与高的骨髓瘤细胞比值及低的血红蛋白值相关。结论　脊柱MRI可反映MM的骨髓受累情况,其MRI表现与骨髓瘤细胞所占百分比值、血红蛋白值之间存在相关性。     

螺旋CT和MRI判断胃癌T分期的价值

目的：探讨螺旋CT（SCT）及MRI对进展期胃癌T分期的价值。方法：通过采用水充盈技术，应用螺旋CT和高场强MR对30例经手术证实的进展期胃癌患者在术前行SCT、MRI平扫及动态增强扫描，并与手术病理结果进行对照。结果：SCT及MRI判断T分期的准确率分别为83．3％（25／30），90．0％（27／30）。SCT及MRI判断Tz期的准确率分别为77．8％（7／9），88．9％（8／9）；T。分期的准确率分别为84．6％（11／13），92．3％（12／13）；T4分期的准确率分别为87．5％（7／8），87．5％（7／8）。结论：MRI对胃癌T分期的判断准确性略高于螺旋CT，MRI以其多平面及多参数成像的特点与螺旋CT在评价胃癌T分期方面进行互补。     

正常垂体高度的解剖与MRI测量对比研究

目的对正常成人垂体高度MRI与解剖测量进行比较.方法采用1.5超导磁共振系统,对垂体连续薄层自旋回波T1加权成像,测量1400例成人垂体正中矢状位高度,并与国内外资料相对比.结果国内正常成人垂体高度均值为6.6±2.1mm,明显大于多数国内外解剖测量资料,统计具有非常显著性差异.结论解剖测量垂体的高度值小于MRI测量的高度值.     

MRI快速场回波技术对椎间盘 突出症的诊断评价

目的评价MRI快速场回波技术对椎间盘突出症的诊断价值。方法对颈、腰椎间盘突出症患者各40例，采用1.0T场强MRI成像系统分别进行SE序列T     

如何在脑MRI轴位图像上识别中央沟及其邻近沟回

目的 探讨在脑MRI轴位图像上识别中央沟及其邻近沟回的具体方法和实际应用价值。资料与方法 随机抽取头颅MRI轴位扫描存档片200份，影像诊断明确排除了颅脑器质性病变，其中男113例，女87例，年龄11-84岁。使用Siemens1.0T超导型磁共振机（Somaris)，头颅扫描基线为听眶线，SE扫描序列，常规行T1和T2WI。分析中央沟及其附近沟回的形态特征并予以形象化命名，以利于实际应用，统计分析各定位征象的敏感性及其价值。结果 中央沟及其附近沟回在MRI轴位图像上具有特征性表现，可归纳为5大征象。（1）驼峰征（hump sign)：出现率为98.5%；（2）倒T字征（reversed Tsign)；出现率为85.0%;(3)十字征（cross sign)；出现率为97.5%；（4）宽带征（wide belt sign)；出现率为100%；（5）分隔征（separation sign)；出现率为98.0%。结论 在正常情况下两侧的中央沟是对称的，在MRI轴位图像上应用上述征象对中央沟的正确识别率可达98.5%。并可由此引伸到CT轴位图像的识别。     

Adrenal schwannoma: CT and MRI findings

We report a case of adrenal schwannoma, an extremely rare retroperitoneal neoplasm. The patient was a 33-year-old man who presented with an abdominal mass that was discovered at abdominal sonography. Computed tomography showed an 8-cm well-circumscribed homogeneous mass that enhanced slightly after intravenous administration of contrast material. Magnetic resonance imaging showed low signal intensity on T1-weighted images and heterogeneously high signal intensity on T2-weighted images. Although these imaging findings are nonspecific, adrenal schwannomas should be included in the differential diagnosis of solid nonfunctioning adrenal tumors.     

脊柱结核的MRI表现及早期诊断

目的 探讨脊柱结核的ＭＲＩ表现及早期诊断。材料与方法 对２２例脊柱结核行矢状位Ｔ１ＷＩ、Ｔ２ＷＩ、Ｐ（Ｎ）Ｉ及轴位Ｔ１ＷＩ;１２例行Ｇｄ－ＤＴＰＡ增强Ｔ１ＷＩ。观察椎体、终板、椎间盘和冷脓肿的信号变化和增强改变。结果 （１）椎体骨炎及终板破坏呈长Ｔ１长Ｔ２信号;（２）椎旁或椎前冷脓肿呈长Ｔ１长Ｔ２均匀无结构信号,且上下跨越范围较大;（３）早期椎间盘信号正常或只出现退变,晚期则被破坏;（４）Ｇｄ－Ｄ     

Intracranial hemorrhage: principles of CT and MRI interpretation

Accurate diagnosis of intracranial hemorrhage represents a frequent challenge for the practicing radiologist. The purpose of this article is to provide the reader with a synoptic overview of the imaging characteristics of intracranial hemorrhage, using text, tables, and figures to illustrate time-dependent changes. We examine the underlying physical, biological, and biochemical factors of evolving hematoma and correlate them with the aspect on cross-sectional imaging techniques. On CT scanning, the appearance of intracranial blood is determined by density changes which occur over time, reflecting clot formation, clot retraction, clot lysis and, eventually, tissue loss. However, MRI has become the technique of choice for assessing the age of an intracranial hemorrhage. On MRI the signal intensity of intracranial hemorrhage is much more complex and is influenced by multiple variables including: (a) age, location, and size of the lesion; (b) technical factors (e.g., sequence type and parameters, field strength); and (c) biological factors (e.g., pO2, arterial vs. venous origin, tissue pH, protein concentration, presence of a blood-brain barrier, condition of the patient). We discuss the intrinsic magnetic properties of sequential hemoglobin degradation products. The differences in evolution between extra- and intracerebral hemorrhages are addressed and illustrated.