Lumbar facet joint capsule: appearance at MR imaging and CT

The joint spaces and synovium of the lumbar facet joints extend beyond the articular surfaces of the joint in the majority of adults. The authors correlated magnetic resonance (MR) imaging, computed tomographic (CT), and axial cryomicrotome sections of 66 facet joints in nine cadavers. Extensions of the synovium and joint space along the superior and inferior articular processes, under the ligamentum flavum, and into the ligamentum flavum could be recognized with use of MR and, less successfully, CT. The injection of a paramagnetic contrast medium into the facet joint facilitated visualization of the capsule on MR images. On the ventral aspect of the lumbar facet joint, MR images showed regions of high signal intensity where the joint space extended into the ligamentum flavum or between the ligamentum flavum and lamina. On the dorsal aspect of the joint, MR demonstrated prominence of the fibrous joint capsule where the joint space extended under it along the inferior articular process or along the superior articular process. The variable appearance of the ventral and dorsal aspects of the lumbar facet joint on CT and MR images is due to extension of the synovium and joint space.     

Unilateral dislocation of the lumbosacral facet joint: Imaging features

Unilateral dislocation at the lumbosacral junction is a rare injury associated with severe hyperflexion and rotation of the lumbar spine. Plain film findings suggesting facet dislocation are usually confirmed with computed tomography. Most surgeons advocate early open reduction, internal fixation, and fusion.     

肺隐球菌病CT表现与临床病理特征分析

目的:分析肺隐球菌病(PC)肺部CT表现及临床、病理特征,提高对该病的认识。方法:回顾分析9例经病理或细菌学证实的PC肺部CT表现,其中肺部有基础疾病者2例。结果:CT表现为孤立病变4例,单叶多发病变2例,双侧病变3例,病变多位于肺外围。CT有3种影像表现:①结节或肿块;②单发或多发斑片影;③斑片影与结节或肿块影混合。9例中出现空洞6例,伴肺段实变1例,伴少量胸水2例,纵隔淋巴结肿大1例。结论:PC肺部CT表现形态多样,病灶多发,具有一定的特征性。病灶形态与病程及免疫力有关,确诊尚依赖病原学及病理检查。     

CT of facet distraction in flexion injuries of the thoracolumbar spine: the "naked" facet

Vertical distraction of the articular processes is an important sign of ligamentous disruption due to flexion injuries of the thoracolumbar spine. In addition to illustrating this finding in cross section (the "naked" facet), computed tomography in the transaxial plane allows assessment of the presence and position of fracture fragments that may encroach on the spinal canal. Image reconstruction in sagittal and coronal planes provides a clear demonstration of the degree of bony compression, facet distraction, and kyphosis associated with flexion injuries without additional patient manipulation or radiation exposure.     

CT patterns of facet fracture dislocations in the thoracolumbar region

Thoracolumbar facets are not as commonly dislocated as are those of the cervical spine. It is, however, crucial to make an early and accurate diagnosis of thoracolumbar facet dislocation since the injury may be unstable and require reduction and internal fixation. This paper presents three major CT patterns of thoracolumbar facet fracture dislocation. The first represents anterior subluxation of the vertebral body with anteriorly locked facets. The second is a lateral vertebral body subluxation with laterally locked facets. The third is an acute kyphosis with little vertebral body subluxation but superiorly dislocated facets. Since the vertebral body subluxation may be missed on axial CT images, these facet-dislocation patterns should be recognized by identifying the paired superior and inferior facets and establishing their congruency. Identification of the facets is accomplished by their orientation with respect to the vertebral body (superior facets are directed posteromedially and inferior facets are directed anterolaterally) as well as by the shape of the articular surface (superior facet articular surface is concave, inferior facet articular surface is flat or convex).     

输卵管妊娠的CT表现和特点

目的探讨输卵管妊娠的CT表现和特点。方法对38例临床怀疑为异位妊娠的患者进行超声检查和CT平扫、增强检查：其中34例手术及病理证实为输卵管妊娠。结果CT诊断输卵管妊娠的敏感度为97．06％，特异度为75．00％，准确度为94．73％。CT诊断输卵妊娠的直接征象为附件区包块内发现完整(4／34，11．8％)或变形的妊娠囊(14／34，41．2％)；间接征像为附件区囊性包块中发现有可强化的异常密度影(8／34，23．5％)；附件区混杂性包块，以实性成分为主，增强后呈轻、中度不均匀强化(19／34，55．9％)；盆腔内子宫旁大片稍高密度影，无明显强化(3／34，8．8％)；子宫直肠窝内可见血性密度影(23／34，67．6％)。输卵管妊娠cT表现特点可归类为孕囊型(4／34，11．8％)；囊肿型(8／34，23．5)；包块型(17／34，50％)；陈旧包块型(2／34，5．90％)；出血型(3／34，8．8％)。输卵管妊娠影像表现与妊娠部位有关；输卵管妊娠影像表现与临床症状有关。结论输卵管妊娠的CT表现有一定的特点，在盆腔肿块的诊断与鉴别诊断时可提供有力的帮助。对临床、B超诊断不肯定的患者，CT是有效的补充检查方法。     

Traumatic thoracolumbar facet instability: characteristic imaging findings

 Objective. To review imaging patterns and injury mechanisms in patients with thoracolumbar facet instability (TFI). Design. Imaging studies for thoracolumbar osseous injuries over a 2-year period were reviewed. Imaging findings, injury pattern and reported mechanism of injury were established for patients with TFI. Patients. One hundred and ten patients with thoracolumbar acute, osseous injuries were studied. Results. Eleven of 68 (16.2%) unstable thoracolumbar injuries demonstrated TFI. Seven (64%) of the eleven TFI patients were unrestrained occupants in a motor vehicle accident (MVA) and the remainder were involved in injuries dominated by blunt impact to the back. Only two (18%) had serious, permanent neurological deficits. Conclusion. TFI is a common injury pattern, particularly for unrestrained occupants in MVAs. Characteristic radiographic, CT and MRI findings are presented and correlated with the injury mechanism and clinical findings.     

Radiological and clinical features of traumatic atlanto-occipital dislocation

Emergency Radiology - We aimed to describe the findings of traumatic atlanto-occipital dislocation (AOD) on cervical spine CTs and differences leading to varying treatment of these patients. We...     

16层螺旋CT诊断颈椎单侧及双侧椎小关节脱位12例

颈椎椎小关节脱位可分为单侧性及双侧性两类,是导致脊髓损伤的潜在性危险之一,尤其是双侧性椎小关节脱位。颈椎正侧位、张口位及双斜位片可使60％以上颈椎椎小关节脱位漏诊,也不能完全地鉴别损伤类型。     

CT表现不典型脂肪肝的MRI诊断

目的：本文通过15例CT平扫表现不典型脂肪肝的MRI资料，回顾性分析其在MRI各序列上的表现和特点，旨在说明MRI检查的诊断价值。方法：15例CT平扫不典型的脂肪肝中，局灶型脂肪肝为3例4个病灶，弥漫型脂肪肝中的正常“肝岛”9例共20个“病灶”，需与其它病变鉴别的不均匀脂肪肝3例，15例均行MRI常规SE序列扫描和梯度回波化学位移同，反相位序列检查。结果：MRI常规扫描仪能辨认少数脂肪含量较多的病灶，而化学位移反相位像上，全部病例均显示含脂病变部分与同相位比较有明显的信号下降，病变与正常肝组织之间的信号对比明显改善。结论：MRI化学位移同，反相位检查对于检出少量脂肪组织很敏感，显著提高了CT表现不典型脂肪肝的诊断准确率。     

Orbital "blow-in" fractures: clinical and CT features

During a 16 month period, seven patients were admitted to our trauma center with "blow-in" fractures of the orbital roof. This injury results from a significant direct blunt force applied to the supraorbital region of the frontal bone with transmission of energy to the thin orbital plate of this bone and displacement of bone fragments downward into the superior orbit. High resolution CT with multiplanar reformation and three-dimensional display proved very useful in identifying and characterizing the bone and soft tissue abnormalities found in our patients. Our experience suggests that CT demonstration of supraorbital frontal bone fractures and/or frontal lobe cerebral contusions is an indication for thin section CT of the entire orbit, even when there is no evidence of a superior orbital rim fracture. Demonstration of an orbital blow-in fracture should prompt careful clinical assessment of the globe, optic nerve, and extraocular muscles to identify and appropriately manage underlying injuries to these structures.     

Intraabdominal panniculitis: clinical, radiographic, and CT features

Intraabdominal panniculitis, also known as lipodystrophy, is an inflammatory condition of adipose tissue that may result in development of large masses containing necrotic fat (nodular intraabdominal panniculitis). Symptoms are secondary to inflammation or mass effect on adjacent organs. Barium studies may show nonspecific inflammatory changes and displacement of bowel loops. Computed tomography (CT) demonstrates inhomogeneous masses containing fat and soft tissue density. The diagnosis of intraabdominal panniculitis has seldom been made prospectively. However, the CT findings are characteristic and can aid in the evaluation and management of patients with this disease.     

Spindle-cell carcinoma of the hypopharynx presenting with a pedunculated appearance: CT and MR features

Spindle-cell carcinoma (SPCC) is a rare tumor that presents biphasic components: squamous-cell carcinoma and sarcomatous features without any differentiation. We present a case of SPCC of the hypopharynx in a 60-year-old man. A well-demarcated mass occupying the hypomesopharynx and presenting a pedunculated appearance was observed originating from the lateral wall of left piriform sinus. High signal intensity on T2-weighted magnetic resonance (MR) images corresponded to the myxoid matrix of the tumor on MR pathologic correlation.     

Retroperitoneal lymphangioleiomyomatosis: CT appearance

Lymphangioleiomyomatosis is a rare disease involving the lung, lymphatic trunk and lymph nodes. Sometimes it appears in the retroperitoneum with or without subsequent development in the lungs. We present a 52-year-old woman with retroperitoneal location of the disease. We discuss the abdominal CT appearance, the cytologic and immunophenotypic features and a preoperative differential diagnosis is attempted. Received: 10 June 1997; Revision received 28 July 1997, Accepted 8 September 1997