Early time-related course of image findings in postmortem MRI: Typical findings and observer agreement in a porcine model.

Purpose To assess early time-related image findings in postmortem magnetic resonance imaging (MRI) and to evaluate observer agreement in a porcine model. Material and Methods Three pigs were examined by MRI at 15 different time points in the first 36 h after death. Two observers independently recorded the postmortem interval (PMI) to the appearance of fluid collection (pleural space, interlobar and interlobular pulmonary fissures and hepatic interlobar fissures), gas accumulation (intrahepatic and intracardial) and blood clotting (aorta and intrahepatic venous vessels). Cohen’s Kappa statistics and intraclass correlation coefficient (ICC) were used to evaluate intra- and interobserver agreement. Results Intrahepatic gas was evident after 12, 17 and 30 h. Also, intracardiac gas was present in all animals. However, no chronological appearance has been observed. Blood clotting in the hepatic vein was observed within 3 min, aortic clotting with a delay of 2–12 h after death. Interlobular pulmonary fluid (median PMI: 2 h, range 2–2 h), pleural effusion (median PMI: 10.5 h, range 9-12 h) and hepatic interlobar fissure fluid (median PMI: 11.5 h, range 11–12 h) displayed a chronological appearance pattern. Qualitative and quantitative detection of most postmortem findings showed excellent intra- and interobserver agreement with Kappa values > 0.8 or ICC > 0.75. Conclusion Pulmonary and hepatic fissural fluid collection as well as intravasal gas accumulation are early time-related image findings in postmortem MRI. The chronological appearance of these findings can be assessed with excellent observer agreement in a porcine model. [ABSTRACT FROM AUTHOR]