Postmortem MRI Characterization of Cadaveric Hypostases in Deceased Newborns

Using postmortem MRI, we studied the features of the development of internal cadaveric hypostasis in dead newborns. Postmortem radiological and pathoanatomical examination of 62 bodies of newborns and infants who died at the age of 1.5 h to 49 days was carried out. After the death was ascertained, prior to MRI, the bodies were stored in a refrigerator at 4°C in the supine position. Depending on the duration of the postmortem period (2-72 h), all observations were divided into eight groups. Prior to autopsy, an MRI scan was performed in T1 and T2 standard modes, followed by analysis of the presence and severity of the gradient line of the intensity of the MR signal in the liver and lung tissue in the ventral (overlying) and dorsal (underlying) areas, as well as the presence of a gradient of the intensity of the blood signal in the heart cavity and in the aortic lumen. The main manifestations of cadaveric hypostasis in the liver and lungs are changes of the MR signal intensity in the ventral and dorsal regions with the appearance of a horizontal gradient of the MR signal intensity, which reflects the location of the body after death. In the heart cavity and in the aortic lumen, there is also a gradient of the blood signal intensity of various severity with the visualization of two or three of its layers. The revealed features of the MRI signal intensity and, accordingly, the presence of its horizontal gradient depended not only on the MRI mode of the study, but also on the studied organ and the duration of the postmortem period. This should be taken into account when analyzing the results of virtopsy and determining the links of thanatogenesis of dead newborns and infants.