CT诊断技术资料汇编.doc

初步CT诊断技术汇编中国援厄立特里亚第八批医疗队Initial CT diagnostic techniques CT的成像原理及图像特点Imaging principles and characteristics of the CT image1、 CT的成像基本原理The basic principles of CT imagingCT是用X线束对人体某部一定厚度的层面进行扫描，由探测器接收透过该层面的X线，转变为可见光后，由光电转换变为电信号，再经模拟/数字转换器（analog/digital converter）转为数字，输入计算机处理。图像形成的处理有如对选定层面分成若干个体积相同的长方体，称之为体素（voxel）。扫描所得信息经计算而获得每个体素的X线衰减系数或吸收系数，再排列成矩阵，即数字矩阵（digital matrix），数字矩阵可存贮于磁盘或光盘中。经数字/模拟转换器（digital/analog converter）把数字矩阵中的每个数字转为由黑到白不等灰度的小方块，即象素（pixel），并按矩阵排列，即构成CT图像。所以，CT图像是重建图像。每个体素的X线吸收系数可以通过不同的数学方法算出。 CT is the level of the body of a unit of X-ray beam to scan a certain thickness, the level received by the detector through the X-ray, visible light converted by the photoelectric conversion into electrical signals, and then the analog / digital converter (analog / digital converter) to digital, enter computer processing. Processing the selected image forming like the same volume level is divided into a plurality of rectangular, called a voxel (voxel), shown in Figure 1-2-1. The information obtained by the scanning of each voxel is calculated to obtain the X-ray attenuation coefficient or the absorption coefficient, and then arranged in a matrix, i.e., a digital matrix (digital matrix), a matrix can be stored in a digital disk or CD-ROM. By the digital / analog converter (digital / analog converter) digital matrix into each number ranging from black to white gray small box that pixel (pixel), and press the matrix arrangement constitutes a CT image . Therefore, CT image is reconstructed image. X-ray absorption coefficient can be calculated for each voxel by different mathematical methods. 2、CT图像特点CT图像是由一定数目由黑到白不同灰度的象素按矩阵排列所构成。这些象素反映的是相应体素的X线吸收系数。不同CT装置所得图像的象素大小及数目不同。大小可以是1.0×1.0mm，0.5×0.5mm不等；数目可以是256×256，即65536个，或512×512，即262144个不等。显然，象素越小，数目越多，构成图像越细致，即空间分辨力（spatial resolution）高。CT图像的空间分辨力不如X线图像高。CT image characteristics CT image is produced by a number of different gray scale from black to white pixels arranged in a matrix of the composition. These pixels reflect the corresponding voxel X-ray absorption coefficient. Different pixel size and the number of different devices resulting CT images. Size can be 1.0 × 1.0mm, 0.5 × 0.5mm range; number may be 256 × 256, namely 65 536, or 512 × 512, that is 262,144 dollars. Obviously, the smaller the pixels, the larger the number, the more detailed the image constituted, namely spatial resolution (spatial resolution) high. Spatial resolution of the CT image is better X-ray images is high. CT图像是以不同的灰度来表示，反映器官和组织对X线的吸收程度。因此，与X线图像所示的黑白影像一样，黑影表示低吸收区，即低密度区，如含气体多的肺部；白影表示高吸收区，即高密度区，如骨骼。但是CT与X线图像相比，CT的密度分辨力高，即有高的密度分辨力（density resolution）。因此，人体软组织的密度差别虽小，吸收系数虽多接近于水，也能形成对比而成像。这是CT的突出优点。所以，CT可以更好地显示由软组织构成的器官，如脑、脊髓、纵隔、肺、肝、胆、胰以及盆部器官等，并在良好的解剖图像背景上显示出病变的影像。CT images are different shades of gray to represent, reflect the organs and tissues of the extent of absorption of X-rays. Therefore, X-ray images with black and white images shown as shadow indicates low absorption areas, namely low-density areas, such as gas-containing multi lungs; the white represents a high absorption zone, that is, high-density areas, such as bone. However, compared with the X-ray CT images, CT density of the high resolution, i.e., high density resolution (density resolutiln). Thus, the density difference between the human soft tissue, though small, is close to the water absorption coefficient are numerous, and can be formed contrast imaging. This is an outstanding advantage of CT. Therefore, CT can better display composed of soft tissue organs, such as the brain, spinal cord, mediastinum, lung, liver, gallbladder, pancreas and pelvic organs, and shows images of lesions on good anatomical images in the background. x线图像可反映正常与病变组织的密度，如高密度和低密度，但没有量的概念。CT图像不仅以不同灰度显示其密度的高低，还可用组织对X线的吸收系数说明其密度高低的程度，具有一个量的概念。实际工作中，不用吸收系数，而换算成CT值，用CT值说明密度。单位为Hu（Hounsfield unit）。x-ray image can reflect the density of normal and diseased tissue, such as high and low density, but no amount of concepts. CT image is displayed not only the density of the different gray level, but also with the organization of the X-ray absorption coefficient of the density level of the degree of description, the concept of having a quantity. In practice, no absorption coefficient, and converted into a CT value with the CT value Description density. Units Hu (Hounsfield unit). CT图像是层面图像，常用的是横断面。为了显示整个器官，需要多个连续的层面图像。通过CT设备上图像的重建程序的使用，还可重建冠状面和矢状面的层面图像，可以多角度查看器官和病变的关系。CT image is a slice images, is commonly used cross-section. In order to display an entire organ, requires a plurality of successive levels of the image. By using the CT device image reconstruction program, but also the reconstruction of coronal and sagittal slice images can be multi-angle view of the relationship of organs and lesions. 3、综上所述:CT图像是层面图像，可以多角度查看器官和病变的关系。CT与X线图像相比，CT的密度分辨力高，即有高的密度分辨力,可以更好地显示由软组织构成的器官，并在良好的解剖图像背景上显示出病变的影像.In summary: CT images are level image, you can see the relationship between the organs and multi-angle lesions. Compared with the CT X-ray images, CT density of the high resolution, i.e., a high-density resolution, the display can be better organ constituted by a soft tissue, and shows the image of the lesion on the anatomical image of good background.CT检查流程及注意事项 CT examination procedures and precautions 1.CT检查由临床医师根据患者病史申请检查。患者检查前须将详细病史及各种检查结果告知临床医师，并请携带有关临床资料如：超声检查、化验、X光、MRI、放射性核素及已做过CT检查等各种检查结果和图片，以供CT医师诊断参考。    1.CT Check the application for examination by the clinician based on patient history. Former patient examination shall detailed medical history and a variety of inspection results to the clinician, and please bring relevant clinical information such as: ultrasound, laboratory, X-ray, MRI, CT radionuclides and has been done Check other test results and pictures for CT physician diagnostic reference. 2.请病人家属陪同前来检查，儿童、不配合者、神志不清者及危重病人需要有关医护人员陪护。 Please come to check the patient's family, accompanied by patients, children, do not match those, unconsciousness and critically ill patients who need health care staff escort. 3.检查前务必除去检查部位的高密度或金属物品。例如：头颅颈部、五官检查中的发夹、耳环，胸部检查中的项链、领带夹、金属饰物及上衣口袋中的金属物品，腹部及腰椎检查中的皮带、手机、钥匙等。进入检查室禁止使用手机。Be sure to check the site before checking to remove high-density or metal objects. For example: head and neck, facial examination hairpins, earrings, necklace chest examination, tie clips, metal ornaments and metal items in a jacket pocket, abdomen and lumbar spine examination belts, cell phone, keys and so on. Prohibit the use of cell phones into the examination room.4.检查过程中病人须尽量配合医（技）师检查，避免运动，以保证图像质量。在胸腹部检查过程中屏气非常重要，有利于提高图像质量，提高效率，一般采用平静均匀呼吸时屏气。Inspection process shall be as patient with the medical (technical) inspection division, to avoid exercise to ensure image quality. In the chest and abdomen during the inspection breath is very important, help to improve the image quality, increase efficiency, the general calm even when breathing breath.5.腹部CT检查最好前一天晚上起空腹。1周内不服含金属的药物，不做胃肠钡剂检查。若已做钡剂检查者，需待钡剂排空后才能检查；如为急诊，应告知CT医（技）师，以免影响图像质量，避免重复检查。检查时听从技术人员指导，保持体位不动，配合检查进行平静呼吸、屏气等。Abdominal CT scan is best played at night the day before fasting. 1 week dissatisfied with the metal-containing drugs, not gastrointestinal barium examination. Ruoyi do barium enema who needed to be in order to check the barium after emptying; the case of emergency, should inform the medical CT (Technology) division, so as not to affect image quality, avoid duplication of inspection. Check obey the guidance of technical staff to maintain position does not move, with the inspection conducted quiet breathing, breath and so on. 6.特殊检查（作碘制剂CT增强扫描或CTA检查）：根据病情和诊断需要，部分病人平扫后需做增强检查或其他特殊扫描，经检查医师与病人或家属协商后方可进行检查，并补交所需费用。患者行增强扫描须本人或家属签署碘对比剂知情同意书。Special checks (for iodine preparations enhanced CT scan or CTA examination): According to the diagnosis of the disease and the need, in some patients after the scan to be done to enhance the examination or other special scan, after consultation with the patient or family physician examination can be carried out checks and pay the required fees. Enhanced scanning patients or their families to be signed "informed consent iodine contrast agent." 7.CT机上配有对讲机，在检查中如有不适或发生异常情况，应立即告知医（技）师。CT machines are equipped with walkie-talkies, at check-in if discomfort or abnormal conditions, shall immediately inform the doctor (Technology) division. 8.孕期妇女严禁进入。Pregnant women allowed to enter. 9.请妥善保管您的CT片，以便下次复查时对比。Please keep your CT slices, so that the next time comparative review.2. CT增强扫描中的适应症及对比剂的副反应 CT enhanced scan indications side effects and contrast agentsCT检查分几种？ CT scan several points? CT检查分为CT平扫、增强扫描和CT血管造影（CTA）以及CT三维成像等。病人不做任何准备直接到CT进行检查称为CT平扫，哪些情况可以直接平扫，脑外伤、出血性或缺血性脑血管病、脑发育异常，全身骨骼病变，肝内胆道结石、泌尿系统结石，全身各器官上的囊肿，肺间质纤维化、支气管扩张，颈、腰椎间盘突出，颈腰椎椎骨性椎管狭窄，各实质性器官肿瘤筛查等。  CT examination is divided into CT scan, enhanced scan and CT angiography (CTA) and CT three-dimensional imaging. Patients without any preparation checks referred directly to the CT CT scan, what circumstances can scan, brain trauma, hemorrhagic or ischemic cerebrovascular disease, brain abnormalities, systemic skeletal disease, intrahepatic bile duct stones, urinary tract stones, cysts on the body organs, interstitial lung fibrosis, bronchiectasis, neck, lumbar disc herniation, cervical and lumbar vertebra spinal stenosis, all solid organ cancer screening and so on.哪些情况需要做增强CT检查，增强CT扫描的意义如何？ What needs to be done significance enhanced CT, CT scan How? 凡是怀疑脑肿瘤、脑血管畸形、炎症，肺肿瘤、纵隔肿瘤，心脑血管病变，全身外周血管病变（阻塞或出血），肝胆胰脾肾、膀胱、前列腺子宫、卵巢以及胃肠道的肿瘤性病变都需要先做CT平扫，再做增强扫描。 Any suspected brain tumors, vascular malformations, inflammation, lung cancer, mediastinal tumors, cardiovascular and cerebrovascular disease, systemic peripheral vascular disease (obstruction or bleeding), liver, gallbladder, pancreas, spleen, kidney, bladder, prostate, uterus, ovaries and neoplastic lesions of the gastrointestinal tract CT scan needs to do first, do enhanced scanning. 怎样做CT增强扫描呢？增强CT扫描是指经静脉注射含碘对比剂（造影剂）后再行CT检查的成像技术，使病变组织与邻近正常组织间的密度差增加，从而提高病变的显示率。病变组织密度增加称为增强或强化，其机制是病变组织内血管丰富或血流缓慢，血脑屏障破坏，含碘造影剂在病理组织中停滞、积蓄而强化。因此增强扫描可反映病理组织性质。常用的碘对比剂有两种：水溶性离子型对比剂泛影葡胺和非离子型对比剂欧乃派克、优维显、碘海醇、欧苏等。由于非离子造影剂泛影葡胺副反应多，现已很少应用。       How do CT scan it? Enhanced CT scanning is used by intravenous injection of iodine-containing contrast agents (contrast agent) after the CT scan imaging technology, the density difference between diseased tissue and adjacent normal tissue between the increase, thereby increasing the display rate of lesions. Diseased tissue density increases called enhanced or strengthened, the mechanism is inside the diseased tissue rich in blood vessels or slow blood flow, blood-brain barrier damage, iodine-containing contrast agents arrest in pathological tissues, savings and strengthened. Therefore, enhanced scan may reflect the nature of the pathological tissue. Iodine contrast agent commonly used in two ways: a water-soluble ionic contrast agent diatrizoate and non-ionic contrast agent Omnipaque, excellent dimensional display, iohexol, Ousu like. Because of non-ionic contrast agent diatrizoate side reactions, is now rarely used.增强CT扫描检查的目的和临床意义有哪些？The purpose and significance of enhanced CT scans have? 1、提高等密度病灶和小肿瘤的检出率 CT虽然具有很高的密度分辨率，但很多病变在CT平扫图像上由于病灶与所处器官之间没有明显的密度差异，CT平扫不能显示出病灶或肿瘤的大小和形态，需要经静脉注射对比剂后的增强CT扫描，人为地增加了病变与正常器官之间的密度差异，就可以清楚地发现CT平扫不能显示的等密度病灶或小肿瘤。CT使用四十年的实践证明，脑、肝、胰、脾、肾等实质脏器内的小病灶尤其是实质性占位，在平扫图像上呈等密度的例子比比皆是，单纯靠平扫难免有漏诊情况，因此，凡是怀疑实质性器官肿瘤需要先做CT平扫，再作增强就不会漏掉等密度的肿瘤。1, and so the density of lesions and improve the detection rate of small tumors : CT Although a high density resolution, but a lot of lesions on CT scan images in the absence of significant density difference between the lesion and in which organ, CT scan does not show the lesion or tumor size and shape, to go through CT scan after intravenous injection of contrast agent, artificially increasing the density differences between lesions and normal organs, we can clearly see CT scan can not show equal density lesions or small tumors. CT using four decades has proved that small lesions of brain, liver, pancreas, spleen, kidneys and other parenchymal organs, especially within the substantive placeholder, was on plain CT images and other examples abound density, simply relying on flat sweep inevitably missed cases, therefore, any suspicion solid organ tumors need to do first CT scan, further enhancements will not miss isopycnic tumors. 2、提高良恶性肿瘤性病变的定性诊断能力 CT平扫不仅检出率低，而且对病灶的定性和鉴别能力也是有限的，动态增强扫描根据病灶增强的有无、程度和增强方式或类型可以提高病灶的定性能力，对典型病例不难作出定性诊断。Benign and malignant lesions improve diagnosis ability: CT scan not only detection rate, but also for lesion characterization and identification capability is limited, dynamic enhanced MRI enhancement based on the presence or absence of lesions, extent and type of enhancement mode or can be improved lesion characterization ability of the typical case is not difficult to make a diagnosis. 3、恶性肿瘤的分期 在已确诊的恶性肿瘤增强CT扫描的目的在于提高肿瘤分期的准确性，为肿瘤进行分期、判断肿瘤手术切除的可能性。Cancer staging: The purpose has been diagnosed with a malignant tumor in the CT scan is to improve the accuracy of tumor stage, tumor staging, surgical resection of the tumor to determine the possibility. 4、鉴别血管还是肿大淋巴结：对于血管性病变的诊断和显示，动态增强扫描更是必不可少的；对血管性和非血管性病变的鉴别，增强扫描同样很重要，如血管和小的淋巴结的鉴别是一个明显的例子。肺门、颈部、盆腔等部位的淋巴结与血管的鉴别在图像上常常遇到困难，通过增强扫描，浓度高的血管与强化不明显的淋巴结之间密度差异增大，很容易区别。因此，在日常工作中，CT增强扫描是必需的，也是必不可少的。 Identification of blood vessels or lymph nodes: For the diagnosis of vascular lesions and display, dynamic enhanced MRI is essential; the identification of vascular and non-vascular lesions, enhanced scan is equally important, such as blood vessels and small identification of lymph nodes is an obvious example. Identification of the hilar lymph nodes, neck, pelvis and other parts of the blood vessels in the image often encounter difficulties, through enhanced scanning, a high concentration of blood vessels and strengthen the obvious difference in density between the enlarged lymph nodes, it is easy to distinguish. Thus, in their daily work, CT enhanced scan is required, is also essential.CT增强目的及适应症Contrast-enhanced CT purpose and indications 增强CT扫描的目的是增加病灶与周围正常组织的对比度或增加供血丰富病变与正常器官之间的对比度，以利发现病灶，或更清晰显示病灶的范围和性质。胸部增强目的在于增加病变与正常组织密度相近的病灶、鉴别病变与血管断面、观察病变血供情况、血管本身有无病变；肝脏增强目的在于增加病灶与正常肝实质之间的密度差，显示平扫不能显示或可疑的病灶、根据增强鉴别病灶的性质、显示肝内外血管结构、区别囊性病变和实质性病变。The purpose is to increase the CT scan lesion contrast with the surrounding normal tissue rich in blood supply or increase the contrast between lesions and normal organs in order to facilitate detection of lesions, or more clearly show the scope and nature of the lesion. Enhanced chest close to the aim of increasing the density of lesions and normal tissue lesions, vascular lesions and differential cross section was observed lesion blood supply, blood itself without lesions; hepatic enhancement aims to increase the density of the lesion and the normal liver parenchyma difference between the level of the display sweep can not be displayed or suspi