Role of Multi Detector CT scan in Detection of Solid Visceral Injuries of Blunt Abdominal Trauma

Abstract

OBJECTIVE: To determine the role of MDCT in the detection of solid visceral injuries in blunt abdominal trauma patients. METHODS AND MATERIALS: A Comparative cross sectional prospective study was performed in 4 months’ period (10th February to 10th June2006). All patients referred for CT scan from emergency department within 24 hours of blunt abdominal trauma were included in the study while patients who presented 24 hours of trauma, hemodynamically unstable patients, patients in which diagnostic lavage was performed and patients who died were excluded from the study. All patients were scanned with Toshiba Asteions multi detector Computed Tomography Scans were obtained from domes of diaphragm to symphysis pubis. Scans were obtained at 0.8 cm/interval with a delay scan time of 50-55 seconds. A slice collimation of 5 mm and pitch of 1.5 were used. 500 ml of diluted oral contrast material sodium   amidotrizoate 0.1 grams, meglumin amidotrizoate 0.66 grams was administered through nasogastric tube 60 minutes prior to the study. Another 250 ml oral contrast was given immediately before CT scan while the patient was on the CT table. Scans were performed before and after   administration of I/V contrast. Iodinated contrast (1.5 -2.0 ml/ kg) was injected with power injector at the rate of 2-3 ml / sec. Images were acquired in soft tissues and lung window setting. In case of suspected fractures, images in bone window were also acquired. The CT results were compared with surgical/ clinical follow up (which are the gold standard reference) for the study. Data was collected with the help of Performa. Statistical analysis was performed with SPSS version 10. Sensitivity, Specificity, negative, positive predictive values   and accuracy were calculated. RESULTS: Patients were selected for the study. Out of these 6 patients were excluded from the study as 2 did not give consent for the study, one expired due to head injury and one presented after 24 hour of trauma and 2 patients had DPL at some other institution before coming to our hospital. Out of 75 patients, there were 60 males and 15 were females with mean age 39+1 years. All patients either had surgical diagnosis of the injured organ involved along with its grading or associated injury of other than solid organs. 

Correct assessment was made in 72 out 75 scans (96%).Incorrect assessment was made in 3 scans (4%).Out of the 72 scans correctly evaluated,58 were true positive and 14 were true negative. Out of the 3 CT scans proven to be incorrectly evaluated, indirect evidence of free fluid was falsely interpreted as solid visceral injury in one patient and delayed rupture of the spleen as negative in two patients. The individual sensitivity, specificity, accuracy, negative and positive predictive values of solid visceral injuries were 98. 3 %, 87.5 % ,96%,93.33%and 96.66 PPV.