What is the main abnormality?
Large volume of free fluid. Not dense enough to be pure haemoperitoneum.
How suspicious of an occult injury should you be?
Highly - the patient is male and there is a large volume of free fluid, which should be considered pathological (only a trace of free fluid in the pelvis is acceptable).
List organs which may be injured in this setting.
Bowel, bladder, bile ducts, solid organs (e.g. liver, spleen).
There is a moderate amount of free fluid within the right upper quadrant and right paracolic gutter, with a small amount of fluid also seen in the left upper quadrant and the mesentery. This fluid is only slightly denser than water / urine, but certainly does not represent merely a haemoperitoneum. The dome of the bladder appear a little thickened and irregular, although the bladder is well distended.
There is no liver injury demonstrated. The spleen, pancreas or adrenal glands and kidneys are normal in appearance. No bowel wall thickening appreciated. Duodenum unremarkable. No lumbar spinal or pelvic fractures. Minor subcutaneous fat stranding in lower anterior abdominal wall, in keeping with seatbelt injury.