Diagnostic Performance of Graded Compression Ultrasonography in Acute Right Iliac Fossa Pain

Abstract

Introduction: Acute right iliac fossa (RIF) pain is a frequent clinical presentation, with acute appendicitis being the most common surgical cause. While computed tomography (CT) offers high diagnostic accuracy, its use is limited in resource-constrained settings due to cost and radiation exposure. This study aimed to evaluate the diagnostic performance of graded compression ultrasonography (USG) in patients presenting with acute RIF pain and to correlate its findings with CT and surgical/histopathological outcomes.
Methods: A prospective observational study was conducted at the Department of Radiodiagnosis, Bir Hospital, Kathmandu, from January to June 2025. Sixty-eight patients with acute RIF pain underwent standardized ultrasonography, and findings were compared with CT and/or intraoperative or histopathological results. Diagnostic accuracy metrics including sensitivity, specificity, predictive values, and Cohen’s Kappa were calculated.
Results: Of 68 patients, 51 (75%) were diagnosed with acute appendicitis, including 42 uncomplicated and 9 complicated cases (appendicular lump, abscess, or perforation). Other diagnoses included ileitis/colitis (n=5), renal/ureteric calculus (n=3), ileocecal malignancy (n=3), ileocecal tuberculosis (n=1), diverticulitis (n=1), lymphadenopathy (n=2), and normal findings (n=2). Ultrasonography demonstrated high diagnostic performance with a sensitivity of 96.08%, specificity of 94.12%, and a positive predictive value of 98%. Key sonographic features in appendicitis cases included the “target sign” (94.1%), appendicolith (54.9%), and free fluid (17.6%). Cohen’s Kappa coefficient was 0.885, indicating near-perfect agreement with CT/intraoperative findings.
Conclusion: Graded compression ultrasonography is a highly sensitive and specific imaging modality for evaluating acute RIF pain. Beyond diagnosing appendicitis, it effectively identified other significant abdominal pathologies. Given its safety, accessibility, and diagnostic reliability, USG should be considered a primary imaging tool, particularly in resource-limited healthcare settings.