Is Multi-Detector Computed Tomography Mandatory after Ultrasound in the Assessment of Stable Patients with Blunt Abdominal Trauma?

Abstract Background: Assessment of blunt abdominal trauma patients is often difficult by clinical means alone. Laboratory tests and imaging studies are cornerstones for evaluation. The focused assessment with sonography for trauma (FAST) examination is important in hemoperitoneum detection. It can be performed in the emergency room, aiding in the initial triage of patients, to determine the need for urgent surgery. If the FAST revealed hemoperitoneum in a persistently unstable patient; laparotomy should be done, in any other circumstance, computed tomography is necessary. Currently, contrast-enhanced multidetector computed tomography (MDCT) is the gold standard imaging technique for the diagnosis of severe abdominal injuries; it aids in determining the amount of damage, and subsequent therapy can be planned. Because of radiation hazards and the high cost of MDCT scans, many studies tried to use the US as the sole imaging modality in blunt abdominal trauma [BAT], especially in vitally stable patients with negative FAST. Aim of Study: To emphasise the circumstances in which the US could be sufficient in the evaluation of hemodynami-cally stable patients with acute abdominal trauma without the need for a MDCT scan, and assess the additive role of multi-detector CT over conventional ultrasound (US). Patients and Methods: Sixty patients presented to the Emergency Room (ER) as victims of BAT in a hemodynami-cally stable condition. After the primary survey and clinical assessment, US was done for the detection of hemoperitoneum and organ injury. Contrast-enhanced MDCT scan was done for confirmation of US findings. Results: For hemoperitoneum detection; the US detected 46 patients as positive, 38 of them were found true positive by MDCT (83%) while the other 8 were false positive. US excluded hemoperitoneum in 14 patients, all were found true negative by MDCT. That gave the US a positive predictive value [PPV] of 83%, a negative predictive value [NPV] of 100%, a sensitivity of 100% and a specificity of 64%. As for solid organ injury (SOI) detection’s US detected 21 patients as positive, 17 were true positive by MDCT (81 %) and 4 were false positive. US excluded organ injury in 39 patients, 30 were true negative by MDCT (77%), while 9 patients were false negative. US had 81% PPV, 77% NPV, 65% sensitivity, and 88% specificity. Conclusions: US is highly accurate for the detection of hemoperitoneum so a negative focused assessment with sonography in trauma (FAST) scan for hemoperitoneum can accurately exclude the need for MDCT. However, MDCT is a valuable adjunctive complementary imaging to US in the detection of visceral organ injuries.