Radiology: Imaging offers much needed update to postmortem exams
“The results of this study clearly show the potential of postmortem CT angiography to change the paradigm in the investigation of the cause of death by introducing a minimally invasive technique for postmortem examination. Imaging and biopsy may augment both clinical and forensic postmortem examinations and serve as a viable compromise or even a substitute for traditional autopsy,” wrote Steffen G. Ross, MD, of the Institute of Forensic Medicine at the University of Bern in Switzerland, and colleagues.
The authors noted that the exact incidence of noncardiac diseases in patients who die after presenting with acute chest pain is not known because autopsies are not systematically performed. Even when they are performed, Ross et al explained that the methods of postmortem examination have changed little since the 19th century. Additionally, the destructive nature of postmortem dissection can further distress relatives of the deceased and might lead to objections from certain religious or cultural groups.
In the past, postmortem CT imaging was limited due to the lack of a feasible method of applying a contrast medium throughout the body. Recent developments, including the use of iodized oil and a diluting alkane with iodinated contrast medium, have made postmortem CTA a more practical option, according to the authors.
To better define the potential of postmortem CTA combined with image-guided biopsy, Ross and colleagues examined the corpses of 20 patients who reported acute chest pain before death. Multiple biopsies of the myocardium were performed, as well as biopsies of lung tissue. Imaging reports were compared with a subsequent autopsy.
In all but one case, the combination of CTA and CT-guided biopsy validated the cause of death reported at traditional autopsy. The one exception was an early myocardial infarction of the papillary muscles, which was missed because the papillary muscles were not included in the biopsy protocol. In seven cases, CT-guided biopsy provided additional histopathologic information.
Ross et al reported that CTA enabled the depiction of findings such as coronary artery disease and coronary thrombosis. It also helped to evaluate cardiac bypasses in situ. Meanwhile, image-guided biopsy was able to supply information about cases of myocarditis and myocardial infarction which would have been unidentified using imaging alone.
As far as noncardiac diseases, cases of aortic dissection, pulmonary embolism and nontraumatic vascular rupture showed complete concordance in all subjects. Image-guided biopsy also enabled the diagnosis of small cell lung cancer and was able to differentiate between normal postmortem clotting and antemortem thromboembolic material, according to the authors.
“Because of the minimally invasive nature of the procedure, postmortem CT angiography allows for an in situ depiction of vascular diseases that are otherwise only detectable by making an extended preparation effort at autopsy, which is accompanied by the danger of accidental destruction of relevant findings,” wrote Ross and colleagues.
They added that the increasing use of radiologic imaging for postmortem exams may lead to a subspecialty of forensic radiology.