Graded compression sonography with adjuvant use of a posterior manual compression technique in the sonographic diagnosis of acute appendicitis.

OBJECTIVE: We evaluated the usefulness of graded compression sonography with the adjuvant use of a posterior manual compression technique for detection of the vermiform appendix and the diagnosis of acute appendicitis.

SUBJECTS AND METHODS: Five hundred seventy consecutive patients referred for suspected acute appendicitis were prospectively examined by original, graded compression sonography with a 5- or a 7.5-MHz linear transducer. A posterior manual compression technique was added for 85 patients whose vermiform appendix was not identified with graded compression sonography. For consensus, another experienced radiologist or a resident observer was in attendance throughout the examination. The detection rate for the vermiform appendix and the diagnostic accuracy for acute appendicitis before and after the adjuvant use of a posterior manual compression technique were obtained, respectively, and final diagnoses were established with the official radiology reports, surgical results, and clinical follow-up.

RESULTS: Graded compression sonography enabled visualization of the vermiform appendix in 485 (85%) of 570 patients. After the adjuvant use of a posterior manual compression technique, the vermiform appendix was found in an additional 57 of 85 patients, with the number of identified vermiform appendices increasing to 542 (95%) of 570 patients. The 57 patients with an additionally found appendix included 11 patients with acute appendicitis. The sonographic diagnosis of acute appendicitis was determined in 312 of 542 patients. Acute appendicitis was proven by surgery in 311 of 332 patients. Sonography was used to establish the diagnosis in 302 of the 311 patients with proven appendicitis; there were 10 false-positive diagnoses and nine false-negative diagnoses. One false-positive diagnosis was acquired after use of the posterior manual compression technique. These results showed more improvement than those of the probabilities for acute appendicitis with single use of graded compression sonography.

CONCLUSION: Graded compression sonography with adjuvant use of a posterior manual compression technique seems to be useful for detecting the vermiform appendix and for diagnosing acute appendicitis.