Ans. C: CT scan Plain radiographs demonstrate a wide variety of abnormal findings. The constitution of findings reflects whether the spleen has sustained capsular rupture. Normal findings on chest and abdominal radiographs do not exclude splenic injury. USG/Focused abdominal sonar for trauma (FAST) is commonly used as the bedside investigation of choice for detection of intra-abdominal blood in abdominal trauma. Diagnostic peritoneal lavage (DPL) is especially useful in the hypotensive, unstable patient with multiple injuries as a means of excluding intrabdominal bleeding. DPL has been largely replaced by FAST. It is extremely sensitive to the presence of intra-peritoneal bleeding, being able to pick up just 20m1 of blood (Sensitivity 85-98%) Relative contraindications to DPL include near term pregnancy (DPL should be carried out supra-umbilically in this situation), presence of a coagulopathy, cirrhosis, and multiple prior abdominal operations. A DPL is deemed positive if blood or bowel contents are aspirated from the abdomen. It is also determined to be positive if on analysis of the dialysate, greater than 100,000 RBC/mml or 5000 WBC/ mm3 are found. False positives on DPL may occur from abdominal wall bleeding from a traumatic catheter placement and from pelvic fractures. CT is the modality of choice for evaluation of blunt abdominal trauma in stable patient because it is not only sensitive, but also has a high specificity. In addition to being able to identify the presence of intra-abdominal fluid, individual organ damage can be identified. Retroperitoneal trauma may be identified and tril trauma not requiring laparotomy may be diagnosed as such.