死後全身電腦斷層檢查於死亡原因調查之應用

Abstract

臨床醫學針對內科疾病併發院外心肺停止之病患, 經施予急救復甦術而恢復自發性循環者, 或重大創傷事件而送醫急救者, 為了釐清心肺停止之原因和創傷後的傷勢評估, 因其無侵入性和相對可近性, 全身電腦斷層檢查為常用手段之一。 而臺灣於2020年8月也開始應用全身電腦斷層檢查於疑非自然死需司法相驗者, 為法醫病理科醫師和第一線的基層法醫師鑑定死亡原因時提供一個體內的影像學證據。

本研究於2019至2020年間, 收案了218位因內科疾病致到院前心跳呼吸停止, 經急救復甦恢復自發性循環後接受了電腦斷層檢查的成年病患進行分析。無顯影劑之電腦斷層檢查可提供27.5%心肺停止原因之證據, 經顯影劑注射後的影響分析則可增加診斷率至43.1%, 最常見的原因包括了急性冠狀動脈疾病、肺炎、顱內出血、呼吸道梗塞和主動脈剝離。另外本研究也於同年份收案了54位因遭遇嚴重創傷事件致三日內死亡之成年病患予分析其電腦斷層的發現, 創傷機轉包含了車禍、高處墜落、平地跌倒、火災、上吊或絞殺、電擊傷和利器傷。電腦斷層檢查於第一時間提供了體內各種多重性創傷的證據, 利於治療方針的規劃以及病人預後之評估, 但對於一氧化碳中毒、窒息和電擊造成的傷害則無法提供決定性的證據。

本研究也收案了33位同時接受死後電腦斷層檢查及司法相驗和解剖的病患予以分析, 包含了15位成年創傷和11位成年內科疾病致死之族群和7位未成年族群, 分析死後電腦斷層於司法鑑定的角色, 再和臨床族群比較死後變化在電腦斷層上可能的顯像。死後電腦斷層和病理解剖的重要發現可達到50.7%的一致性, 兩者分別額外提供31.3%和18%的異常發現, 而影像上的重大發現尤其在創傷機轉致死亡結果的族群為甚。死後電腦斷層檢查在不正常的空氣累積, 骨折, 顱內病兆, 出血性休克, 異物探查等皆能提供具信服力的證據。然而其判斷內科疾病猝死的敏感度, 實質內臟損傷的辨別, 出血來源之偵測, 以及毒藥物過量等死亡原因表現比較差。若能導入顯影劑注射相信更加可以增加以上問題的診斷率。

死後電腦斷層檢查可以在短時間內以非侵入性的方式作全身的掃瞄檢查, 提供非血腥的圖像證據。若能夠利用此檢查於司法調查, 或可以起到一個守門員的角色, 有需要者再進一步進行司法解剖, 相信可以為相驗的判斷提供更大的信心, 為死者說出更多不能說出口的話。

Computed tomography (CT) examination is commonly employed in early evaluation of the cause of cardiac arrest and the consequences of hypoxic-ischemic change after regained of spontaneous circulation (ROSC). It is also recommended as a non-invasive tool in patients with major traumatic events for timely detection of overall injuries and treatment strategy planning. Since August of 2020, postmortem computed tomography (PMCT) had introduced into the legal system as an adjunctive to autopsy examination. We would like to investigate the role of this image study in both of the clinical and forensic settings.

Our study had analyzed the CT images of 218 out-of-hospital cardiac arrest (OHCA) patients as well as 54 patients whom inevitably passed away within three days after major traumatic events during 2019~2020 in our emergency department. Unenhanced CT examination disclosed cause of cardiac arrest for 27.5% of nontraumatic OHCA patients. The diagnostic accuracy improved to 43.1% with the help of contrast enhancement. Overall, CT examination performed well in detection of acute coronary syndrome, pulmonary infection, airway obstruction and aortic emergency. It also helps in early diagnosis of multiple traumatic internal injuries in our cohort, whom mostly encountered with motor vehicle accident, fell from height, fell on the ground, fire accident, hanging or strangulation, electrocution and penetrating trauma. However, it is not useful in detection of carbon monoxide poisoning, asphyxia and microscopic injuries after electrocution.

This study also enrolled 33 patients whom simultaneously received unenhanced PMCT and autopsy in medicolegal examination, comprising of 26 adults and 7 pediatrics. 15 of the adults had major traumatic events. In overall, PMCT achieved agreement as much as 50.7% with autopsy findings. Each of them had additionally provided 31.3% and 18% of pathologic findings. PMCT had extra-ordinary performance in detection of abnormal air accumulation, skeletal fracture, intra-axial and extra-axial cranial injuries, hypovolemic shock and foreign body localization. Nevertheless, it is not sensitive in detection of natural illness, minor organ injury, source of bleeding and toxicologic mortality.

Inherited advantages of PMCT included non-destructive in nature, fast-processing time and ability of postprocessing multiplanar reconstruction serve as an extra-ordinary measure in virtual dissection. Court presentation with vivid but bloodless picture evidence may reduce psychological impact on non-medical persons. Incorporation of PMCT into medicolegal system may help to preserve more evidence in forensic system. The diagnostic performance of PMCT may further improve with the introduction of contrast media in the future.