Correlation between Hounsfield Unit values of blood in CT on immediate postmortem CT after cardiopulmonary resuscitation and antemortem hemoglobin levels

Abstract

The Hounsfield Unit (HU) values of blood in computed tomography (CT) on a live CT scan and hemoglobin levels have a positive linear correlation. The purpose of this study was to elucidate whether the same correlation could be observed on postmortem CT (PMCT) immediately after failed cardiopulmonary resuscitation (CPR) to determine its potential in diagnosing antemortem anemia. We enrolled 200 patients with nontraumatic cardiopulmonary arrest (103 men, 97 women) who could not be resuscitated after being transferred to our hospital. A blood count was taken at the start of the infusion, as well as an immediate PMCT. The CT values of regions of interest in the ascending aorta were measured at three levels. Pearson's correlation coefficient (R) between the HU values of blood in CT and hemoglobin was calculated. Results The maximum infusion volume during CPR was 500 ml in 169 cases and 1000 ml in 31 cases. There was a positive linear correlation between the HU values of blood in CT on immediate PMCT and hemoglobin at the time of initiation of infusion (R = 0.74). A strong correlation was observed between the HU values of blood in CT on immediate PMCT after CPR within the infusion range of 1000 ml and the antemortem hemoglobin levels, proposing the possibility of diagnosing antemortem anemia at least in a very early postmortem interval.