Urinary bladder volume measured in whole-body CT scans is a useful marker for alcohol intoxication.

Abstract

The aim of this study was to investigate whether urinary bladder volume (UBV) and blood alcohol concentration (BAC) correlate in a cohort of emergency trauma patients. Furthermore, the feasibility of semi-automated 3D-CT volumetry for urinary bladder volumetry calculations in whole-body CT examinations was elucidated. Whole-body CT scans of 831 individuals treated in the emergency department with suspected multiple injuries were included. Manual 3D-CT volumetry of the urinary bladder was performed and the mechanism of injury, patient demographics, BAC, serum creatinine, and hematocrit were retrospectively analyzed. Semi-automated calculation of UBV was performed in 30 patients. Statistical analysis included ROC analysis to calculate cut-off values, sensitivity, and specificity. The Mann-Whitney test and Spearman's correlation coefficient were used to detect significant correlations between UBV and BAC. Manual 3D-CT volumetry showed maximum sensitivity and specificity with a cut-off value for urinary bladder volume of 416.3mL (sensitivity 50.9%; specificity 76.3%; AUC 0.678). With a cut-off value of 4.2mL/μmol for the creatinine quotient (quotient of serum creatinine and UBV), the sensitivity was 64.2% (specificity 67.0%; AUC 0.681). Semi-automated 3D-CT volumetry resulted in lower UBV values compared to those obtained with manual 3D-CT volumetry. Semi-automated 3D-CT volumetry is a reliable method to quantify UBV. UBV correlates with positive BAC results. A UBV above 416mL seen on an initial whole-body CT must raise suspicion of alcohol intoxication. The creatinine quotient is an even more sensitive and specific parameter for the detection of alcohol intoxication.