胸、腰椎骨折的影像学诊断

Imaging of Thoracic and Lumbar Spine Fractures 胸、腰椎骨折的影像学诊断 Mark W. Anderson, MD Fractures of the thoracic and lumbar spine are common in patients who have sustained highenergy spinal trauma, and are associated with injury to the spinal cord in up to 50% ofcases. Accurate early assessment is essential because delay in diagnosis may result in thedevelopment of neurologic complications. Clinical assessment of these patients is oftenchallenging, and as a result, diagnostic imaging usually plays a central role in theirmanagement. The purpose of this chapter is to explore this role by answering the followingquestions: What are the imaging options? Who should be imaged? How should they beimaged? and What are the imaging findings for the most common types of thoracolumbarfractures? 在高能量脊柱创伤患者中，胸腰椎骨折较为常见，50%以上的病例可以出现脊髓损伤。因此，对于胸腰椎骨折的早期评估非常重要，因为延误诊断可能会导致神经功能并发症的发生。对于胸腰椎骨折患者的临床评估难度较大，因此影像学检查在其诊断中占据了中心地位。本文旨在对以下问题做初步的探索：影像学检查的选择有哪些？那些患者应该进行影像学检查？如何检查？常见的胸腰椎骨折影像学表现有哪些？ 【正文部分】 Fractures of the thoracic and lumbar spine are usually theresult of high-energy injuries such as motor vehicle acci-dents or falls from a significant height. They have been re-ported to occur in 4%-5% of patients arriving at a level 1trauma center and are associated with spinal cord injury inup to 50% of cases. Accurate early assessment is essentialbecause delay in diagnosis may result in the development orprogression of neurologic complications. Clinical assess-ment can be challenging, particularly in a patient with an altered level of consciousness or a “distracting” injury else-where, and a delay in diagnosis has been reported to occur inup to 20% of these fractures, most often secondary to insuf-ficient imaging. 胸腰椎骨折常见的致伤原因为高能量创伤，如车祸或高处摔伤。1级创伤中心所接受的病例中，约4%-5%为胸腰椎骨折，同时这些患者中伴有脊髓损伤的高达50%以上。因此，对于胸腰椎骨折的早期评估非常重要，因为延误诊断可能会导致神经功能并发症的发生。当患者意识不清或伴有其他部位的损伤时，临床评估往往难以进行。据报道，延误诊断的概率可达到20%，其原因往往是没有进行必要的影像学检查。 The purpose of this chapter is to review the role of diag-nostic imaging in the work-up of patients with suspectedthoracolumbar fractures by posing 4 questions: (1)What arethe imaging options? (2) Who should be imaged? (3) Howshould they be imaged? and (4) What are the imaging find-ings for the most common types of thoracolumbar fractures? 本研究旨在回顾影像学诊断在拟诊对胸腰椎骨折患者进行评估的作用，并初步对一下四个问题进行了初步解答：影像学检查的选择有哪些？那些患者应该进行影像学检查？如何检查？常见的胸腰椎骨折影像学表现有哪些？ What are the Imaging Options? Radiography Radiography is typically the first modality used to evaluatethe thoracolumbar spine after trauma. In the thoracic spine,anteroposterior (AP) and lateral views are usually supple- mented with a swimmer’s lateral view because the upper 3 to4 thoracic vertebrae are often poorly demonstrated on a stan-dard lateral film due to the overlying soft tissues of the upperchest and shoulders9 (Fig. 1). In the lumbar region, AP andlateral views are typically sufficient, but may need to be sup-plemented by a coned down viewof the lumbosacral junction(Fig. 2; Table 1). 影像学检查的 方法 快递客服问题件处理详细方法山木方法pdf计算方法pdf华与华方法下载八字理论方法下载 有哪些？ X线（普放） 普放通常是评估胸腰椎创伤的首选方法。在胸椎检查中，通常拍摄前后位（AP）和侧位片，有时可让患者摆成游泳者侧位姿势，以便更好地现实T3、T4和以上的椎体（收到上胸部和肩部软组织影的影响，常规侧位片难以显示）（图1）。在腰椎检查中，常规拍摄AP和侧位片，有时在拍摄中需要压迫腰椎以更好地显示腰骶角（图2；表1）。 Computed Tomography The advent of multidetector helical computed tomography(CT) has revolutionized spine imaging. This technique allowsfor very rapid scanning (typically less than 1 min each forscans of the thoracic and lumbar spine) and results in theacquisition of a continuous dataset that can be used to createextremely thin axial slices as well as exquisite reconstructedimages in virtually any plane (typically coronal and sagittal)(Fig. 3). In most centers, CT has supplanted conventional radiographs in blunt trauma patients who meet certain crite-ria that will be discussed in the next section. An additionaladvantage of this technique is that data from CT scans of thechest, abdomen, and pelvis obtained to evaluate for visceralinjury can be used to simultaneously generate reconstructedimages of the spine without the need for rescanning the pa-tient. CT is clearly superior to radiographs for demonstratingfractures of the thoracolumbar spine with a sensitivityof 94%-100% compared with 33%-73% for radiogr-aphs.CT is also more accurate than magnetic reso-nance imaging (MRI) for detecting fractures, particularlythose involving the posterior elements, and for demonstrat-ing the size and location of osseous fragments. 计算机体层摄影术（CT） 多探头螺旋CT的出现是影像学史上的一场***。这种技术不但扫描速度快（对胸椎或腰椎的扫面时间通常小于1分钟），而且能够得到连续的轴向薄层图像，并在任意平面进行矢状位或冠状位重建（图3）。在大多数医疗中心，CT已经取代了普放作为某些钝器伤患者的首选检查方法。此外，在对腹腔脏器损伤进行CT扫面评估后，不需要重新扫面即可通过重建技术得到脊柱的影像。对于胸腰椎骨折的诊断，CT明显优于普放，敏感性为94-100%，而普放仅有33-73%。同时，在伴有后方附件损伤的骨折类型或需要对骨折片进行定位和估计大小时，CT较磁共振显像（MRI）对骨折的诊断更为精确。 Analysis of images in all 3 standard planes is necessary because some fractures (eg, “Chance-type”) may be missed on axial images alone. Additionally, images should be viewed using “bone” windows to detect osseous injuries as well as “soft tissue” windows to look for associated abnormalities such as a disc protrusion or epidural hematoma (Table 1). 对于某些类型的骨折，在进行CT检查时，需要对3中常规位置的影响都进行分析。例如，Chance骨折在轴位片中可能难以判断。此外，使用CT诊断骨折需要使用骨窗，而使用软组织窗检查是否伴有椎间盘突出或硬膜外血肿（表1）。 Magnetic Resonance Imaging Given its exquisite soft tissue contrast, MRI is used in a com- plementary manner with CT. While CT is best for detecting fractures, MRI is superior for demonstrating soft tissue pa- thology such as intrinsic cord injury, ligament pathology, hematoma, or muscle tear16 (Fig. 4). T1-weighted sequences provide a good overall display of anatomy and are recognized by the low signal intensity of the cerebrospinal fluid on these images. T2-weighted imaging, which results in bright signal from fluid, is best for detecting pathology because of the increased fluid content in areas bone or soft tissue injury. A gradient echo sequence is useful for detecting hemorrhage within the cord or epidural space given the prominent black signal that is demonstrated with this technique in blood products owing to their iron content. Finally, either short TI-inversion recovery techniques (STIR) or fat-saturated T2- weighted sequences are the most sensitive for detecting mar- row edema related to trabecular injury, and are also useful for identifying soft tissue injuries (Table 1). 磁共振显像 由于MRI对于软组织的有很好的对比显像能力，故常作为CT检查的补充方法。CT是诊断骨折的最佳方法，而MRI是诊断软组织病变的最佳方法（如脊髓损伤、韧带病变、血肿或肌肉撕脱）（图4）。T1加权显像能够很好地显示解剖层次并且能够分辨出低信号的脑脊液。T2加权显像中，液体显示为高亮信号，因此最适合骨或软组织损伤周围液体量增加的诊断。梯度回波序列可以用来诊断脊髓内或硬膜外隙的血肿，由于血肿含有铁元素，故表现为极暗的信号。短反转时间恢复序列(STIR)或脂肪饱和T2加权序列对于骨小梁损伤导致的骨髓水肿的诊断敏感性较高，并可以用来诊断软组织损伤（表1）。 Who Should Be Imaged? 应该对那些患者进行影像学检查？ A delay in diagnosis of a thoracolumbar fracture has been shown to result in a higher incidence of neurologic injury, thus highlighting the need for rapid and accurate assessment of these patients, and raising the important question of which patientswith a history of spine trauma should undergo further investigation with diagnostic imaging? 目前已经证明一旦延误胸腰椎骨折的诊断，则神经功能损伤的发生率较高。因此，对于此类患者病情的评估应快速并且准确。哪些有脊柱创伤病史的患者需要进行进一步的影像学检查？这是值得我们研究的问题。 Despite the array of modalities available, not all patients with a history of thoracolumbar spine trauma should be eval- uated with diagnostic imaging. There is a reasonable consen- sus in the literature that imaging is not needed for a patient who is awake, alert, and without a major nonspinal injury who does not complain of spinal pain or tenderness to palpation. Although some studies have reported the occur- rence of “asymptomatic” fractures of the thoracolumbar spine that were missed at initial presentation, others believe that these misdiagnoses would be better described as “occult” injuries because many, if not all, were missed because of the patient suffering form an altered sensorium (head injury or intoxication) or the presence of another major, “distracting” injury. 尽管已有多种影像学检查方法可供选择，但并不意味着每个胸腰椎创伤的患者都需要接受影像学检查。对这一问题，目前已有共识：意识清醒、有警觉性和未诉脊柱疼痛、压痛，且不伴有其他部位大型创伤的患者不需要接受影像学检查。尽管部分报道指出有时首诊可能遗漏部分症状不典型的胸腰椎骨折，但也有学者认为这些误诊由隐形损伤所导致，因为此类患者往往伴有头部损伤或中毒等严重的非脊柱损伤。 As a result, several authors have put forth a numerous criteria that are useful for determining which patients should undergo further workup with diagnostic imaging. These include (1) a high energy mechanism (fall from 10 ft, ejection during amotor vehicle accident, pedestrian struck by an automobile, etc.), (2) an altered level of consciousness either froma head injury or intoxication, (3) amajor distract- ing injury, or (4) a known fracture anywhere in the spine (because of the known occurrence of multilevel, noncontig- uous spinal fractures in blunt trauma patients). Additionally, a patient reporting spine pain or tenderness to palpation on examination should undergo imaging as should any patient with a neurologic deficit after trauma. Although these criteria suffer from low specificities and positive predictive values, they have been shown to be highly sensitive for detecting thoracolumbar fractures. 很多学者都提出了可用以判断患者是否需要进行影像学检查的标准。其中，需要对患者进行影像学检查的标准有：（1）高能量致伤（高处跌落、车祸、汽车撞伤等）；（2）由头颅损伤或中毒导致的意识水平变化；（3）其他的大型非脊柱创伤；（4）已知的任何部位的脊柱骨折（在钝器伤中患者往往存在多阶段的非连续性骨折）。此外，当患者在体检时主诉脊柱疼痛或压痛，应当接受进一步的影像学检查。尽管这些指标尚缺乏专科性，阳性预测的价值低，但研究证明其对于发现胸腰椎骨折具有很高的敏感性。 How Should They Be Imaged? Historically, conventional radiography has been considered to be the gold standard for screening blunt trauma patients for spine injuries, but this has been changing since the advent of multidetector CT scanning. 如何选择不同的影像学检查方法？ 以往普放被认为是筛选钝器伤患者是否存在脊柱损伤的金标准，但这一认识已经随着多探头CT的出现而改变。 Screening: Radiography or CT? Given the documented superiority of CT over radiography for detecting spine fractures, (sensitivity of 95%-100%for CT vs 60%-70% for radiography), the question must be raised as to whether there is any role for conventional radiography in this patient population. Although screening the spine with CT is now recommended for patients who have a history of high-energy trauma, radiographs are probably adequate for those who have sustained a low-energy injury. But even with a low-energy mechanism, if there is any suggestion of a fracture on radiographs, further evaluation with CT is indicated because of the known limitations of radiographs for detecting thoracolumbar fractures, particularly in the upper thoracic region. 筛查：普放还是CT？ 鉴于众多的文献已经证实CT在发现脊柱骨折方面远较普放为优（CT敏感性为95-100%，普放60-70%），我们需要考虑的是普放在脊柱骨折患者的诊断中是否还有应用价值。尽管目前推荐使用CT对高能量创伤后的患者进行脊柱损伤的筛查，对低能量致伤的患者使用普放检查已经足够，但如检查结果存在骨折征象，则需要进行进一步的CT检查。这是因为普放发现胸腰椎骨折的能力有限，特别是上胸椎骨折。 Additionally, the severity of injury is commonly underestimated with radiographs. For example, up to 20% of burst fractures are misdiagnosed as simple anterior compression fractures using radiographs alone.As such, CT should be performed when there is any question of a fracture on spine radiographs (Fig. 5). 此外，普放检查往往容易低估脊柱创伤的严重性。例如，单独使用普放检查，近20%的爆裂性骨折被误诊为单纯性前缘压缩性骨折。总之，经过普放检查疑有脊柱骨折的患者都应接受进一步CT检查（图5）。 CT is now unequivocally recommended as the screening modality of choice for blunt trauma patients who are at high risk for spinal injury. In addition to better fracture detection and characterization, CT can provide a comprehensive scan of the entire spine, which is important given the presence of noncontiguous spine fractures in up to 20% of these patients. Additionally, a comprehensive scan of the entire spine can be obtained more rapidly with CT than with conventional radiographs, and the overall radiation dose to the patient is lower when CT is used as the only screening modality. As many blunt trauma patients will undergo CT scans of the chest, abdomen, and pelvis for possible visceral injuries, it has become common practice to use the data from these scans to generate high resolution images, including sagittal and coronal reconstructions, without the need for additional dedicated scanning of the spine. These reconstructed images have been shown to be highly sensitive, and clearly superior to radiographs, in this regard, although optimization of scanning parameters is necessary for best results. 对于钝器伤患者如存在脊柱损伤风险的，推荐进行CT检查。CT检查不仅能更敏感地发现骨折，还能够完整地显示整个脊柱形态，这在对非连续性脊柱骨折（约占脊柱外伤的20%）的诊断中非常重要。此外，应用CT可以更快地得到整个脊柱的影像，并且当仅使用CT进行筛查时，患者受到的总体辐射量较小。由于大部分钝器伤患者均接受CT检查，得到胸、腹和盆腔的影像，以筛查是否存在脏器损伤，因此，医务人员可以使用这些高清晰图像进行矢状位或冠状位重建，而不需要进一步进行脊柱的精细扫描。研究证实，重建后的图像有很高的敏感性，明显优于普放，但是，为了得到最佳的临床证据，需要在检查过程中选择最佳的扫描参数。 Magnetic Resonance Imaging MRI should be reserved for specific indications in patients who have sustained trauma to the thoracolumbar spine. These include the presence of a neurologic deficit, evaluation of possible ligamentous injury (based on clinical findings or the presence of a known burst fracture), and high clinical suspicion of injury in a patient with normal radiographic and/or CT studies. The ability of MRI to directly display the cord, disc material, epidural hematoma, and the stabilizing ligaments make it a powerful complementary modality to CT that is best for fracture detection and depiction of osseous fragments. 磁共振成像 对于存在持久性胸腰椎损伤的患者是否应进行MRI检查，有特定的指征，包括神经功能缺损、需要对可能存在的韧带性损伤进行评估（基于临床检查发现或已知的爆裂性骨折）和高度怀疑脊柱损伤但其他影像学检查阴性的患者。MRI能够清晰直观地显示脊髓、椎间盘、硬膜外血肿和韧带的稳定性，因此，MRI作为除CT外，检查患者是否存在骨折或骨折碎片的最重要方法。 Before proceeding with MRI, however, the patient must be screened for any contraindications to scanning. Some implants such as a cardiac pacemaker or ferromagnetic intracranial aneurysm clip are considered absolute contra- indications to MR scanning, while other objects may be considered “MR conditional” or “MR safe.” A comprehensive discussion of MR safety is beyond the scope of this article, and a review of pertinent literature is mandatory when designing and implementing a comprehensive screening system. 在进行MRI检查前，应仔细排除患者是否存在禁忌证。人工植入物如心脏起搏器或强磁性颅内动脉瘤夹是MRI检查的绝对禁忌，其他的植入物不影响MRI检查的进行。在此我们不详细讨论MRI安全性的相关问题，但是我们应当在开展临床工作前自行复习有关的文献。 Imaging Findings 影像学发现 Normal Anatomy 正常解剖结构 Radiographs Vertebral alignment is assessed on the lateral view as are vertebral body heights. Mild wedging of the vertebrae near the thoracolumbar junction is a common finding in asymp- tomatic individuals, and often considered a normal or “de- velopmental” variant. However, caution must be exercised in the setting of trauma, because this “normal” variant often cannot be differentiated radiographically from an acute com- pression injury. 普放 对脊柱形态的评估包括通过侧位片显示椎体高度。在症状不典型的病例中，常常可以发现熊腰交界处椎体楔形变，容易误认为正常或发育畸形。因此，面对创伤患者，应该提高警惕，充分进行鉴别诊断以排除急性压迫性损伤。 Vertebral alignment should also be assessed on the AP view along with the interpediculate distance (the distance between the inner margins of the pedicles). The distance between the pedicles normally decreases from the level of T1 through T6 and then increases gradually from T6 through L5. Paraspinal soft tissue “stripes” are also visible on the AP film of the thoracic spine with the stripe on the left normally wider than that on the right owing to the presence of the descending aorta in that region (Fig. 1). 对脊柱形态的评估同样可以通过前后位片显示椎弓根间隙（椎弓根内侧缘之间的距离）。该间隙在T1至T6平面逐渐较小，在T6至L5平面逐渐增加。在AP片上通常能够发现椎旁的软组织线影，正常时左侧较右侧宽，因为降主动脉走行在脊柱左侧（图1）。 Computed Tomography Osseous anatomy should be evaluated using a “bone win- dow” display that provides for optimal assessment of cortical and trabecular detail. Although all 3 standard planes are use- ful for evaluating the bones, sagittal images are most useful for assessing vertebral and facet alignment. Similarly, soft tissue structures should be evaluated using a dedicated “soft tissue” display. When viewing these windows, normal epidural fat can be differentiated from the thecal sac and from adjacent intervertebral discs, often allowing for detection of epidural hematoma or a trauma-related disc protrusion (Fig. 6). CT 应使用骨窗进行骨骼系统的评估，同时可以很好地显示松质骨和皮质骨的细节情况。轴位、矢状位和冠状位影像对骨骼的诊断均有价值，但矢状位影像最常用于椎体和小关节形态的评价。同样的，对软组织结构进行评价应使用软组织窗显影，此时，能将正常的硬膜外脂肪组织和鞘膜囊、邻近的椎间盘区别开，由此能够发现硬膜外血肿或创伤相关的椎间盘突出（图6）。 Magnetic Resonance Imaging The appearance of tissues on MR images depends on the scanning sequence used. In the adult, fatty (yellow) marrow predominates within the spine such that the vertebral elements are of predominantly high signal intensity (similar to subcutaneous fat) on T1-weighted images. Likewise, the marrow seems dark gray on STIR or fat-saturated T2- weighted images because of the dampening of fat signal in- herent to those sequences. The epidural fat shows similar signal characteristics. The spinal cord is of intermediate sig- nal (similar to skeletal muscle) on all pulse sequences, whereas the surrounding cerebrospinal fluid will appear dark on T1-weighted images and very bright on T2-weighted im- ages (“myelogram effect”). A normal intervertebral disc ap- pears gray on a T1-weighted sequence, but shows differenti- ation between the high signal nucleus pulposis and lowsignal annulus fibrosis on T2 or STIR images. Finally the supporting ligaments show low signal intensity on all imaging sequences with the exception of the interspinous ligaments that contain abundant fat. MRI MRI影响中组织的显示情况取决于扫描序列的种类。成人中以黄（脂肪）骨髓为主，因此，椎体及附件在T1加权图像中表现为高信号（类似于皮下脂肪），而在STIR或T2加权脂肪饱和序列图像中，表现为暗灰色影像，因为在这两种序列中，脂肪信号受到了抑制，硬膜外脂肪的MRI表现大致相同。脊髓在所有序列图像中均表现为中等轻度信号（类似骨骼肌），而其周围的脑脊液在T1加权图像中为低信号，在T2加权图像中为高信号（脊髓造影效应）。正常的椎间盘在T1加权序列中为灰色影像，但在T2或STIR序列中，髓核表现为高信号，纤维环为低信号。起支持作用的韧带在所有的序列中均表现为低信号影像，其中棘间韧带因含有大量的脂肪成分，故表现为高信号。 Thoracolumbar Fractures 胸腰椎骨折 General Comments The type of injury that occurs with blunt trauma to the spine is related to the forces acting upon it at the moment of injury and may involve flexion, extension, compression, distraction, rotation, or shear forces. In general, pure compressive or distractive forces tend to produce fractures, whereas rota- tory and shear forces often result in dislocations. 总体评价 脊柱钝器伤的损伤类型取决于暴力作用于脊柱性质，可造成过曲、过伸、压缩、牵张、旋转和剪断伤。总的来说，单纯压缩性或牵张性外力作用容易导致骨折，而旋转和剪切力通常导致关节脱位。 Most injuries of the thoracic and lumbar spine occur near the thoracolumbar junction for a variety of reasons: (1) the ribcage provides additional stability for the first 9 thoracic vertebrae, (not the case from T10 through T12 owing to the presence of “floating” ribs at these levels); (2)motion is great- est in this region of the thoracolumbar spine; and (3) the facet joints transition from a predominantly coronal orientation in the upper thoracic spine to a more sagittal orientation in the lumbar spine, resulting in less resistance to flexion in the lower thoracic and lumbar regions. Thoracic spine injuries above the thoracolumbar junction are less common, but have a high incidence of associated neurologic injury. This is thought to occur because inju- ries in this region typically require a high-energy mechanism to overcome the inherent stability related to the ribs. Another factor is that the size of the spinal canal is smaller relative to the cord in this region, compared with other regions of the spine. 大部分脊柱损伤发生部位在胸腰椎连接处，原因有以下几点：（1）肋弓形成的胸廓结构增加了T1-T9的稳定性，（不包括T10-T12，因为在该水平只有浮肋存在）；（2）胸腰段是脊柱活动范围最大的位置；（3）小关节从上胸段到腰段，逐渐由冠状位朝向为主转变为矢状位朝向，因此其在下胸段和腰段不能很好地抵抗屈曲应力。胸腰椎连接段以上的胸椎损伤不多见，但其伴发神经功能损伤的概率较高，因为发生在此部位的损伤往往由高能量暴力所致，致伤力超过了肋骨所能维持的脊柱稳定度。另一个原因是在此部位，不同于脊柱的其他部位，椎管较脊髓的相对宽度较为狭窄。 Classification Systems 分型系统 In 1984, Denis proposed a 3-column classification systemforthoracolumbar injuries. The anterior column was defined as the anterior longitudinal ligament as well as the anterior two-thirds of the vertebral body and adjacent discs; the middle column included the posterior one-third of the vertebral body and adjacent discs along with the posterior longitudinal ligament; and the posterior column was defined as the osseous and ligamentous structures posterior to the posterior longitudinal ligament. The importance of the middle column for spine stability was emphasized. Thoracolumbar fractures were also divided into “minor” and “major” groups. Minor fractures included those involving the spinous process, trans- verse process, and pars intra-articularis.Major fractures were broken into 4 categories: compression, burst, flexion–dis- traction, and fracture dislocation. 1984年Denis提出了胸腰椎损伤的3柱分型系统。前柱包括前纵韧带和前2/3的椎体及其邻近的椎间盘；中柱包括后1/3椎体及其邻近的椎间盘和后纵韧带；后柱包括后纵韧带背侧的骨与韧带结构。中柱在保持脊柱稳定性中的重要作用尤其值得强调。胸腰椎骨折也可以分为轻型和重型两组。轻型骨折包括棘突、横突和关节内部的损伤；重型骨折分为4类：压缩、爆裂、屈曲牵张骨折和骨折脱位。 In light of subsequent investigations that showed that the integrity of the posterior ligament complex (PLC)was a better indicator of spinal