头部计算机体层成像
头部计算机体层成像[1]（英语：computed tomography of the head）又称头部电脑断层扫描摄影[2]，是指将一系列从不同方向扫描头部的X射线获得的数据经由计算机程序转为头部（颅脑）的横断面影像的检查方法。[3]其获得的横断面影像可用于检查诊断脑损伤和其他神经系统疾病，亦可用于诊断颅骨、鼻窦的情况或作为脑外科手术的引导图像。[4]不过，CT扫描会使受检者冒着最终患上癌症的风险暴露在电离辐射下，有些特殊的CT扫描方式使用的造影剂甚至可能使一些人产生过敏反应。[4]
| 头部计算机体层成像 | |
|---|---|
 使用静脉注射造影剂后的自颅底至颅顶之头部计算机体层成像 | |
| ICD-9-CM | 87.03 |
| OPS-301 code | 3-200, 3-220 |
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使用
由于CT扫描的准确性、可靠性、安全性及其广泛的可用性，是手段已成为头部创伤的首要诊查方式。患者一旦出现脑损伤，就会发生微循环受阻、自我调节受损、脑水肿或轴索损伤，并表现为临床上，生化检查上或是影像上的变化。故此对脑损伤正确的治疗管理应当基于对症状进展的正确诊断和鉴别，运用CT扫描便可精确检测并定位颅内血肿、脑挫伤、水肿或异物。[4]
即便在紧急情况下，当一名成年患者的头部伤势被医生依据现有的指南判断评估为轻伤时，是患者应避免采用CT检查，如若是儿童则应留在急诊室先行临床观察再做决定。[5] 有诸多病患仅因轻微伤势前往急诊室寻求头部CT扫描检查。事实上，头部CT扫描虽可以明确颅骨骨折或是颅内出血的情况，惟这类情况即便在急诊室也都不常见，同时也不是轻微伤势，故此对于一般的轻微伤势通常没有必要执行该检查。[5] 临床实验表明，只有在遇到紧急情况并有指征表明需要进行CT检查时，方才具有有效性和安全性，在这种情况下，也是为了能够基于影像资料而制定下一步的治疗方案和跟踪患者病史。[5]
头部CT或是磁振造影（MRI）检查不能作为常规检查手段诊断脑震荡，要鉴别该病，应当由训练有素的医疗保健服务提供者跟进。[6] 在脑震荡患者的头部扫描影像中，通常看不到与之相关的异常影像，故此不应将头部CT检查作为诊断脑震荡的常规手段。[6] 在担心发生颅骨骨折，局部性神经系统病症或是其他症状加重时，CT或许是一项有用的检查手段。[6] 而MRI检查可能有助于检查随时间推移而恶化的病症或是可疑的结构性病变。[6]
头部CT检查有时应用于突发性听力丧失的患者，[7]惟当没有其他神经系统病变指征、外伤史、耳病史的时候，CT扫描无效且不应用于突发性听力丧失的检查。[7]
眼部观察窗
诊断者可以使用专用的眼部观察窗来检查诊断眼部相关疾病。[10]CT扫描可由专业的眼科医生操作以检查异物（尤指金属物体）、骨折、脓肿，蜂窝组织炎、鼻窦炎、颅内出血）、眼球突出，眼睛的弥漫性毒性甲状腺肿， 并评估眶尖和海绵窦的情况。[10]
与MRI相比较
当确定头痛的原因是否为肿瘤，血管疾病，后颅窝病变，延颈髓质病变或颅内压力异常时，头部核磁共振（MRI）扫描能比头部CT更好地提供辅助资讯，同时也没有把受检者暴露到电离辐射下的风险。[11] 当需要进行神经成像且MRI不可用、或在紧急情况下怀疑有出血，中风或者创伤性脑损伤时，CT扫描或许可用于头痛查因。[11]
MRI在评估海绵窦和眶尖情况时具有更高灵敏度。[10]
头部MRI有能够评估颅内钙化情况的优点。[12]
注意事项
尽管头部CT可以获得头部冠状位，矢状位，和两者各自再处理后的影像资料，惟在获取冠状位资料时，要求受检者伸展其颈部关节，故此当有潜在的颈部关节损伤风险时，应避免其过度伸展。[10]
头部CT扫描增大了人们罹患脑癌的风险，尤以儿童为主。到2018为止，10岁以下的儿童中每3000-10000人就有1例罹患癌症的风险。[13]
参见
参考资料
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- ^ 存档副本. [2021-11-10]. （原始内容存档于2021-11-10）.
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- ^ 7.0 7.1 American Academy of Otolaryngology – Head and Neck Surgery, Five Things Physicians and Patients Should Question, Choosing Wisely: an initiative of the ABIM Foundation (American Academy of Otolaryngology – Head and Neck Surgery), [2013-08-01], （原始内容存档于2013-09-01）, which cites Stachler, R. J.; et al. Clinical Practice Guideline: Sudden Hearing Loss. Otolaryngology–Head and Neck Surgery. 2012, 146 (3 Suppl): S1–35. PMID 22383545. doi:10.1177/0194599812436449 （英语）.
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- ^ Khan, FR; Henderson, JM. Deep Brain Stimulation Surgical Techniques. Lozano, AM; Hallet, M (编). Brain Stimulation: Handbook of Clinical Neurology. Handbook of Clinical Neurology 116. Amsterdam: Elsevier. 2013: 28–30. ISBN 978-0-444-53497-2 （英语）.
- ^ 10.0 10.1 10.2 10.3 Kunimoto, Derek; Kunal Kanitkar; Mary Makar. The Wills eye manual: office and emergency room diagnosis and treatment of eye disease. 4th. Philadelphia, PA: Lippincott Williams & Wilkins. 2004: 360–361. ISBN 978-0781742078 （英语）.
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