Early Postmortem Interval Estimation in Forensic Radiology: A Proof-of-Concept Study Using qMRMI and Tractography in...

Estimating postmortem interval (PMI) is a difficult task in daily forensic practice, because of all the limitations of most of the methods used for its determination. Over the years, numerous attempts have been conducted to overcome these limitations. Among these, the improvement and innovation of postmortem radiological techniques may play an important role. In this preliminary study, a novel approach for early postmortem interval estimation (ePMI) using quantitative magnetic resonance molecular imaging (qMRMI) is proposed. The study made use of a pig heart, whose anatomical and structural characteristics are known to be like those of humans. The sample was obtained from the commercial food chain, having been taken immediately after the animal was slaughtered. The pig heart was maintained at 17 °C degree. Radiological investigations have been conducted using a 1.5 T MRI scanner, and 2 scans have been performed. Fractional anisotropy (FA), tractography and susceptibility weighted changes due to the heart degradation processes have been monitored. The image acquisition was performed at 3.5 h after death (T0) and 24 hours after death (T1). Results showed measurable time-dependent variations, with FA and AD decreasing and ADC and RD increasing, because of the progressive disorganization of normal myocardiocytes architecture in the postmortem era. Although limited to a single case and two time points, this exploratory study suggests that postmortem qMRMI could be a potentially powerful tool for early PMI estimation. In the future, further studies with larger sample sizes and multiple intervals are needed to validate these preliminary observations.