Shuji Okazaki

Cardiothoracic ratio in postmortem chest radiography with regard to the cause of death

It is difficult to examine the intact in situ status of thoracic organs, including the heart and lungs, after opening the chest at autopsy. The present study investigated the pathological diagnostic significance of the cardiothoracic ratio (CTR) with regard to heart and lung weight in postmortem plain chest radiography. The pathological diagnostic significance of the CTR in postmortem plain chest radiography using serial forensic autopsy cases of adults (>19 years of age, n=367, within 72 h postmortem) was retrospectively investigated. In natural deaths, CTR was larger for heart diseases, and was smaller for pulmonary infection and gastrointestinal bleeding, showing correlations to the heart weight except in cases of hemopericardium. In traumatic deaths, CTR was larger in cases of fire fatality and acute methamphetamine intoxication, and varied in cases of blunt injury, showing correlations to the heart weight. However, CTR was smaller for sharp instrument injury and drowning, independently of the heart weight. These findings suggest that postmortem CTR (median, 55.6%, measured using a mobile X-ray apparatus) primarily depends on the heart weight, but is substantially modified during the process of death: the CTR may be enlarged by cardiac dilatation due to terminal congestive heart failure, but may be reduced by inflated lungs in drowning or hypovolemia due to fatal hemorrhage. CTR showed a mild correlation to the right diaphragm level, which was also related to the cause of death, but was independent of the left diaphragm level. Plain chest radiographic findings may also be helpful in investigating the pathophysiology of death, and are to some extent comparable with clinical findings. This also suggests the potential usefulness of postmortem CT and MRI for analysis of terminal cardiac function.

Analysis of postmortem biochemical findings with regard to the lung weight in drowning

To clarify drowning death, positive evidence for aspiration of the immersion medium and the subsequent fatal mechanism is necessary. This study investigated biochemical findings with regard to lung weight in drowning cases of adults (n=56, >18 years of age, <48 h postmortem: salt water, n=19; fresh water, n=21; brackish water, n=16), using acute cardiac death cases (n=240) as controls. The biochemical markers used in this study were urea nitrogen (UN), sodium (Na), chloride (Cl), calcium (Ca) and magnesium (Mg) in the blood and pericardial fluid (PCF). The left-to-right ratio of cardiac blood UN levels was lower for drowning, showing an inverse correlation to the total lung weight. There was a mild postmortem decrease in serum and PCF Na and Cl levels; however, left cardiac serum and PCF Na, Cl, Ca and Mg levels were higher for saltwater drowning, and left cardiac serum Na and Cl levels were lower for fresh water drowning. Correlation of the left cardiac serum level with lung weight was positive for Na, Cl and Mg in saltwater and brackish water drowning, and was also positive for Ca in saltwater drowning. There was an inverse correlation with lung weight for PCF Na and Cl levels in freshwater drowning. These findings suggest that analyses of serum and pericardial markers in relation to lung weight are useful for evaluating the composition and amount of aspirated medium when investigating drowning death.

Potential risk factors for sudden cardiac death: An analysis of medicolegal autopsy cases

Chronic kidney disease and elevated serum C-reactive protein (CRP) have been suggested as clinical risk factors for cardiac attacks. The present study investigated postmortem blood urea nitrogen (BUN), creatinine (Cr) and CRP levels in the peripheral blood of sudden cardiac death cases. Adult autopsy cases of ischemic heart diseases (n=153, >20 years of age), including acute myocardial infarction (AMI, n=71), recurrent myocardial infarction (RMI, n=47), acute ischemic heart disease without infarction (AIHD, n=27) and chronic ischemic heart disease (CIHD, n=8), were examined and compared with chronic congestive heart disease (CHD, n=24), spontaneous cerebral hemorrhage (SCH, n=17) and mechanical asphyxiation (n=32). BUN was slightly higher for RMI and CHD, although Cr was slightly higher for SCH. CRP was higher for AMI than for AIHD. The correlation between BUN and Cr levels was significant for AMI, AIHD and CHD, but insignificant for RMI and CIHD. Heart weight was larger for all heart diseases and SCH than for asphyxiation, and was larger for RMI and CHD but lower for AIHD and CIHD among them. Body mass index (BMI) was slightly higher for AMI, RMI, AIHD and CHD, remaining within the reference interval in most cases, but was lower for CIHD. These findings suggest different risk factors or etiologies, including active atherosclerosis, latent renal failure, dehydration and cardiac hypertrophy, for sudden deaths due to these heart diseases.