【医学知识】你不知道的事：放射学的秘密（7）
《Radiology Secrets Plus》是由宾夕法尼亚大学E. Pretorius和Jeffrey Solomon博士主编的以问答形式深入浅出的介绍相关放射性与影像诊断学内容的图书。该书总结了影像诊断学在实践过程中需要注意的100个知识要点，本公众号将持续推送翻译介绍。上一期我们介绍了：肌腱肌肉撕裂伤的典型影像诊断以及颅脑CT诊断部分。本期推送的主要内容涉及各种影像学检查方法的应用，敬请期待!
61. 第八颈神经根没有对应的椎体，末端位于第七颈椎和第一胸椎之间。所以，颈神经根末端位于同序号椎体上方，而胸椎和腰椎神经根末端位于同序号椎体下方。
C8 is anerve root without a body. It exits between C7 and T1. As a result, cervicalnerve roots exit above the pediclesof the same-numbered body; thoracic and lumbar nerve roots exit below the pedicles of the same-numberedbody.
62. One should be consistent in describing spinaldegenerative disc disease. A disc bulge is a diffuse, symmetric extension ofthe disc beyond the end plate. A disc protrusion is a more focal extension ofthe disc in which the “neck” is wider than the more distal portion. A discherniation is an extrusion of a portion of the disc in which the “neck” is thenarrowest part. A disc sequestrum is a free disc fragment in the epidural spacethat has lost connection to the disc.
（译者能力有限，欢迎读者补充翻译该段，谢谢！）
63.脊髓炎性和血管性病变可能与肿瘤的形态相似（脊髓炎症在CT中表现为脊髓轻度增粗和密度不均，血管性病变在平扫CT中亦可能表现为增粗和密度不均影，早期未发生骨质破坏的肿瘤也有可能呈现炎性或血管性影像表现）。
Inflammatory and vasculardisorders of the spinal cord may mimic neoplasms.
图为血管性脊髓病
图二为脊髓肿瘤
64.在头颈部癌症患者的淋巴结中，除了已确诊证实的情况，低密度影可以被认为是转移性疾病主要特征。
Low density in a lymph node in an adult with head andneck cancer is characteristic of metastatic disease until proven otherwise.
图为颈部淋巴结转移瘤，可见低密度肿大淋巴结
65. 腮腺是唯一含有淋巴结的唾液腺。
The parotid glands are theonly salivary glands that contain lymph nodes.
图为腮腺巨淋巴瘤
66. 舌骨以上的颈部病变应首选MRI诊断，而舌骨下的颈部疾病分析应首选CT扫描。
Necklesions above the hyoid bone should be studied first with MRI. Pathologic findings of the neck below the hyoid bone should be primarily imaged with CT scanning.
67. 传导性听力丧失的影像学检查首选CT检查，而感音神经性聋则首选MRI。
CT isthe imaging modality of choice for conductive hearing loss. MRI is the imagingmodality of choice in adult-onset sensorineural hearing loss.
68.对病变位置的区分是鉴别诊断的第一步，椎管内肿瘤及其他病变可分为硬膜外（外囊）病变、髓外硬膜内（髓外内硬膜囊）病变和髓内（脊髓内）病变。
Tumors and other lesions within the spinal canal maybe classified as extradural (outsidethe thecal sac), intradural-extramedullary(inside the thecal sac, but outside the cord), or intramedullary (inside the cord). Making this determination is thefirst step to selecting the correct differential diagnosis for a lesion.
69.氟脱氧葡萄糖（FDG）正电子发射断层扫描（PET）为40%的外科治疗病例带来了革新。在一些病例中，远处转移癌或复发性癌提示该癌症难以被治愈，也就是说手术切除的方法已经没有太大的作用了。有20%的患者，(PET)可以避免肿大结节被外科误判为良性而不进行手术的情况，从而手术可以及时进行。（PET/CT在肿瘤方面的应用（1）鉴别肿瘤的良、恶性：如患者肺部有一单个结节，经PET/CT检查，若该结节代谢活性不高，提示良性病变可能性大，对手术的选择应当慎重。反之，若结节代谢活性增高，提示恶性可能，要采取积极的治疗措施，包括手术。（2）肿瘤分期：肿瘤分期是决定患者治疗方案的重要依据。PET/CT对患者进行全身显像，一次显像可提供脑、肺、淋巴结、肝、肾上腺和骨骼等全身各器官有无转移的信息，有利于对肺癌、乳腺癌、结肠癌、卵巢癌和淋巴瘤等多种肿瘤进行精确的临床分期。以诊断淋巴瘤为例，PET/CT更加准确，这是因为CT或MRI是将增大的淋巴结（>1cm）视为转移，其中不乏由于慢性炎症引起的淋巴结增大，或将已受到肿瘤组织侵犯的正常大小的淋巴结误判为正常。而PET根据淋巴结的代谢活性进行判断，比只根据大小进行判断更为准确。（3）疗效评估：由于PET/CT具有很高的灵敏性及其功能代谢显像的特点，对放射治疗、化疗疗效的判断更加准确灵敏，有利于指导临床医师及时调整治疗方案。（4）鉴别肿瘤治疗后坏死、纤维化与残留或复发：PET/CT可以鉴别化疗、放射治疗和手术治疗后的肿瘤坏死、纤维化与残留或复发，而其他影像手段难于做到。（5）帮助制定肿瘤放射治疗计划：PET/CT能够帮助放射治疗师勾画更为合理的的生物靶区，帮助制定放射治疗计划。（6）肿瘤原发灶的寻找：已明确有肿瘤转移灶的患者，通过PET/CT检查，可以进一步寻找肿瘤的原发病灶。）
Fluorodeoxyglucose (FDG) positron emission tomography(PET) changes the surgical management of patients in up to 40% of cases. Insome cases, distant metastases or restaging indicates that the cancer isinoperable, thus preventing surgery that would have not been useful. In as manyas 20% of patients, PET shows that enlarged nodes that may have preventedsurgery from being considered were actually benign, so that surgery can beperformed.
70.“过度曝光”在骨扫描中是指着大量亚甲基二磷酸（MDP）被骨吸收，而没有通过肾脏和膀胱排泄的或明显被软组织吸收。癌症患者若出现“过度曝光”意味着出现广泛骨转移（这一点只能提示全骨广泛转移而不能分辨单独区域）。
A “superscan” on bone scan implies that so much of themethylene diphosphate (MDP) is taken up by the bones that there is nosignificant excretion in the kidneys and bladder or uptake in the soft tissues.In a patient with cancer, a “superscan” implies widespread osseous metastasesthat cannot be individually distinguished but rather occupy almost the entire skeleton.