每天朗讀一段醫(yī)學(xué)影像學(xué)英語(yǔ)文章

 Acute PE is a relatively common event with a wide spectrum of clinical presentation that ranges from small asymptomatic and incidentally detected subsegmental PE to life-threatening central PE causing hypotension, myocardial infarction, and cardiogenic shock. 

Pulmonary emboli are most often the result of thrombi dislodged from the deep veins of the legs. Risk factors for PE include advanced age, malignant disease, pelvic or abdominal surgery, orthopedic surgery in the lower limbs, prolonged immobilization, obesity, congestive heart failure, and trauma. Dyspnea and chest pain, often pleuritic in nature, are the only symptoms reported by >50% of patients with PE.

The chest radiograph is seldom, if ever, diagnostic of PE, and the main role of chest radiography is to identify important alternative diagnoses such as congestive heart failure and pneumonia. On rare occasions, findings suggestive of PE may be present including wedge shaped air-space opacities typically located at the costophrenic sulci, regional hypoperfusion evident as areas of decreased lung attenuation and paucity of vascular markings , and an enlarged pulmonary artery .

CT has become the method of choice for imaging PE in clinical routine in most institutions. Negative predictive value of CT has consistently been shown to surpass 96% both with single-detector and multidetector techniques. Underlying lung disease, inpatient status, and results of V/Q scan do not appear to have appreciable effects of the negative predictive value. A clear benefit of CT is the depiction of alternative diagnoses not otherwise suspected when pulmonary embolus is absent.

The diagnosis of PE is usually straightforward, relying on the direct observation of a central filling defect surrounded by a rim of contrast in a pulmonary artery. Often emboli lodge at bifurcation points and continue into both branch vessels. A sharp vessel cutoff or absence of vessel filling also provides evidence of pulmonary embolus but may be more difficult to perceive. 

（以上主題節(jié)選自心胸影像病例匯）

Notes:

1. embolism  [??mb??l?z?m] n. 栓塞

2. spectrum [?sp?ktr?m] n. 光譜; 波譜

3. hypotension [?ha?p?'ten??n] n. 血壓過(guò)低

4. myocardial [?ma??'kɑ:d?rl] adj. 心肌的

5. infarction [?n?fɑ:rk?n] n. 梗塞形成

6. cardiogenic [?kɑ:d?o?'d?en?k] adj. 心源性的

7. emboli ['emb?li:] n. 栓子

8. orthopedic [?:θ?'pi:d?k] adj.整形手術(shù)的

9. dyspnea [d?sp'ni:?] n. 呼吸困難

10. pleuritic  [pl?'r?t?k] adj. 肋膜炎的

11. costophrenic [k?s't?fren?k] 肋膈的（胸膜）

12. sulci [s?ls?] 溝

13. bifurcation [?ba?f?'ke??n] n. 分歧，分叉部

【Acute pulmonary embolism (PE)急性肺栓塞】

急性肺栓塞在眾多臨床疾病中相對(duì)常見(jiàn)，從輕微的沒(méi)有癥狀的，到檢查時(shí)偶然發(fā)現(xiàn)的亞段肺栓塞，到有生命危險(xiǎn)的中央肺栓塞，可引起低血壓、心肌梗死、心源性休克。

肺栓塞最常見(jiàn)的原因是下肢深靜脈血栓脫落。PE的危險(xiǎn)因素包括：年齡、惡性疾病、骨盆或腹部手術(shù)、下肢的骨科手術(shù)（矯形手術(shù)）、長(zhǎng)期臥床、肥胖、充血性心衰和創(chuàng)傷。呼吸困難和胸痛，實(shí)際上通常由于肋膜炎，據(jù)報(bào)道，這是半數(shù)以上肺栓塞的僅有癥狀。

平片上很少得出肺栓塞診斷，平片主要用來(lái)證明并發(fā)的重要征象，得出替代性診斷，比如充血性心衰或肺炎。一些少見(jiàn)的病例中，某些征象可提示肺栓塞。包括：典型位于肋膈角的楔形空腔病變，密度減低、肺血管紋理稀疏的低灌注區(qū)，肺動(dòng)脈擴(kuò)張。

CT是大多數(shù)懷疑肺栓塞患者的常規(guī)臨床檢查方法。CT的陰性預(yù)測(cè)值和超過(guò)96%一種或多種檢查方式的結(jié)果一致。潛在肺疾病、住院患者、V/Q結(jié)果對(duì)于陰性預(yù)測(cè)值似乎沒(méi)什么預(yù)測(cè)作用。CT很明確的好處是可以直接描述那些代替性診斷，而不是單純懷疑是否有肺栓塞。

PE的診斷通暢很直觀，直接看到中央充盈缺損、外周動(dòng)脈壁的征象。栓子通常停留在分叉處，進(jìn)而進(jìn)入各分支血管。銳利的血管截?cái)嗷驔](méi)有血管的充盈缺損也可提示肺栓塞，但是可能不易發(fā)現(xiàn)。

來(lái)源：每天朗讀一段醫(yī)學(xué)影像學(xué)英語(yǔ)文章

圈主

深圳市人民醫(yī)院放射科副主任醫(yī)師楊敏潔