Potential turf battle looms with medical examiners over virtual autopsy scans

CT image shows severely displaced fracture through third upper thoracic vertebrae in decedent who suffered multiple injuries in a motor vehicle crash. (Provided by B. Daly)

Multislice CT is a promising tool for autopsy, and it's likely that scanners will eventually be installed in many of the major medical examiner's offices around the country. Who will read these cases remains to be seen, however, according to researchers from the University of Maryland Medical Center.

Dr. Barry Daly, chief of abdominal imaging and vice chair for research, and colleagues evaluated the sensitivity and potential role of CT as a replacement for or adjunct to conventional autopsy in the investigation of traumatic accidental or nonaccidental death within the Maryland medical examiner (ME) system.Researchers used a 40-slice CT scanner to prospectively image 20 decedents within 24 hours of death following blunt (n = 14) or penetrating (n = 6, five ballistic) trauma. Two radiologists interpreted scans by consensus and compared them with ME autopsy results for major findings and cause of death.Imaging correctly identified 92 major findings (sensitivity 95.5%) and all 14 causes of death in cases of blunt trauma. Six major false-negative CT findings included two nondisplaced atlanto-occipital subluxations and lacerations of the bronchus, right heart, ascending aorta, and liver. All 26 major ballistic fragments recovered at autopsy were accurately localized by CT, but 13 known pathways were incompletely or not identified, especially where no fragments remained. CT identified seven major findings (three cases of air embolism, three major fractures, and one lung laceration) not detected at conventional autopsy.

Researchers evaluated CT findings as:

• comparable to autopsy in 13 cases (all blunt)
• a helpful adjunct in six cases (five penetrating)
• of no additive value in one case

Investigators have since analyzed 40 cases with similar results, Daly told Diagnostic Imaging. It's only a matter of time before many ME offices install CT scanners, he said. How this potential turf battle will play out in the U.S. is only conjecture. For now, the only formal training program for MEs to read CT scans is in Bern, Switzerland.

"Presently, there is no reimbursement plan. Nobody knows how it will pan out," he said. Daly, who presented the study at a press conference on Tuesday, said that CT can replace conventional autopsy in cases with major injuries, such as those resulting from a motor vehicle crash. All states are required by law to perform an autopsy in cases of sudden and unexplained deaths. Of the 8000 such deaths referred to the chief medical examiner of the state of Maryland last year, approximately one-half required full autopsy.CT autopsy compares favorably with conventional autopsy in several ways. In cases of suspicious death, the noninvasive procedure does not damage or destroy key forensic evidence, as can happen during a conventional autopsy, Daly said. In addition, CT can be used in situations where autopsy may be prohibited by religious or cultural beliefs. CT autopsy is considerably less expensive than conventional autopsy and can be performed in a fraction of the time. A forensic medical examiner requires several hours to conduct a full autopsy, while CT scanning and interpretation can be completed in about 30 minutes."Autopsy is mandatory in deaths involving gunshot wounds, but CT can serve as a powerful adjunct to the conventional exam," Daly said. "Performing CT imaging first may speed up a conventional autopsy, especially when it comes to locating ballistic fragments, which are so important to criminal investigations."