Acute abdomen: Added diagnostic value of coronal reformations with 64-slice multidetector row computed tomography

RATIONALE AND OBJECTIVES: We sought to assess retrospectively the added value of coronal reformations from isotropic voxels obtained with 64-slice multidetector row computed tomography (CT) of the acute abdomen. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board and informed consent was waived. Multidetector helical 64-section CT (section thickness, 0.6 mm; pitch 1.75; table speed 35 mm/sec) was performed in 100 patients (60 women and 40 men; age range, 9-/+85 years; mean age, 45.2 years) with acute nontraumatic abdominal pain who had been referred from the emergency department. Axial images were reconstructed with 5-mm-thick sections at 5-mm intervals. The second data set was reformatted coronally, with 3-mm-thick sections at 3-mm intervals. Four independent, blinded readers with various level of training interpreted first the axial scans alone and then followed immediately by the coronal scans. Confidence in the visualization of anatomy and pathology was scored on a 5-point scale. The final diagnosis was determined by surgical and pathologic reports and by clinical follow-up in those who did not undergo surgery. RESULTS: Based upon the individual patient's clinical history and other comorbid factors, 92 patients received intravenous contrast and 90 patients received oral contrast. In 45 patients, no CT abnormalities were detected for an explanation of the abdominal pain. Mean sensitivity and specificity of axial CT alone were 92.5% and 91%, respectively. No significant differences in sensitivity and specificity were observed for the use of combined axial and coronal images. For the most inexperienced reader, the coronal reformations were helpful in 95% of cases, while for the most experienced reader, the coronal reformations were helpful in 35% of the cases. The coronal images were deemed helpful in an average of 62.3% of the cases for the four readers. However, diagnosing subtle pathology in the abdominal wall was difficult on coronal reformations alone. Overall, coronal reformations improved diagnostic confidence and interobserver agreement over axial images alone for visualization of normal abdominal structures and in the diagnosis of abdominal pathology. CONCLUSION: Axial and coronal reformations of 64-section multidetector row CT have equal sensitivity and specificity for the diagnosis of acute abdominal pathology. However, coronal reformations improved the diagnostic confidence for all readers but most significantly for the least experienced. Therefore, radiology departments with residents should consider routinely generating coronal images in patients with acute abdominal pain.