Diagnostic Utility of Ultrasound in Acute Appendicitis in Correlation with Total Leukocyte Count

Abstract

Objective: To evaluate the diagnostic utility of ultrasound (US) in the diagnosis of acute appendicitis in correlation with total leukocyte count (TLC). Materials and Methods: This cross sectional comparative study was conducted at the Radiology and Pathology Departments of CMH Lahore from 1st February 2007 to 31st January 2008. A total of 125 suspectedpatientsof appendicitis were included in the study through non-probability purposive sampling. They all underwent US evaluation and laboratory assessment (TLC). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of US findings and TLC were calculated keeping surgical findings and histopathology of the removed appendix as gold standard whenever appendecectomy was carried out. Results:Among 62 patients finally proven to be suffering from acute appendicitis US correctly diagnosed the same in 55 (89%), whereas a normal appendix was visualized in 30 (48%) out of the remaining 63 non – appendicitis patients. The most accurate appendiceal finding for appendicitis was adiameter of 6 mm or larger, with a sensitivity of 96%, specificity of 97%,NPV of 98%, and PPV of 98%.The lack of visualization of the appendixwith US had a NPV of 82%. An increase in TLC had a PPV of 66%, whereas normal TLC had a NPV of 73% whereas those of US were 96% and 90% respectively. By utilizing US as an adjunct to clinical evaluation, negative appendectomy rate was lessened to 3.2%. Conclusion: US have better diagnostic utility than TLC in the diagnosis of acute appendicitis.