Radiology: Volume 256: Number 3—September 2010
Jinxing Yu, MD Ann S. Fulcher, MD Deng-Bin Wang, MD Mary A. Turner, MD Jonathan D. Ha, MD Madison McCulloch, MD Robert M. Kennedy IV, MD Ajai K. Malhotra, MD Robert A. Halvorsen, MD
Purpose: To retrospectively determine the frequency and impor-tance of a small amount of isolated pelvic free fluid seen at multidetector computed tomography (CT) in male patients who have blunt trauma without an identifiable cause.
Materials and Methods: Institutional review board approval was obtained, and the requirement for informed consent was waived for this HIPAA-compliant study. One thousand male patients with blunt trauma who underwent abdominopelvic CT at a level 1 trauma center between January 2004 and June 2006 were entered into this study. The CT images of the 1000 patients were reviewed independently by two abdominal radiologists. CT scan assessment included evaluation for presence or absence of pelvic free fluid, any traumatic or nontraumatic cause of the free fluid, pelvic free fluid at¬tenuation and volume measurements, and determination of the location of pelvic free fluid. Interobserver agree¬ment was determined with K statistics, and the Student t test was used to assess differences in the mean volume and mean attenuation of the pelvic free fluid in the pa-tients with and those without injury.
Results: Pelvic free fluid was identified in 10.2% (102 of 1000) of patients. A small amount of isolated pelvic free fluid with-out any identifiable cause was identified in 4.8% (48 of 1000) of patients by reader 1 and in 5.0% (50 of 1000) of patients by reader 2 (K value, 0.76) and was located at or below the level of the third sacral vertebral body in all 49 patients with isolated pelvic free fluid. The mean vol-ume and mean attenuation of the small amount of isolated pelvic free fluid were 2.3 mL ±1.5 (standard deviation) and 8.1 HU ± 3.9, respectively. None of the patients in this group had an undiagnosed bowel and/or mesenteric injury.
Conclusion: In male patients with blunt trauma, a small amount of isolated pelvic free fluid with attenuation equal to that of simple fluid and located in the deep region of the pelvis likely is not a sign of bowel and/or mesenteric injury.