551 Ultrasound Scans Versus Computerised Tomography Scans in the Diagnosis of Acute Appendicitis: What Is the Preference?

Aim Acute appendicitis (AA) is one of the most common surgical presentations. Timely diagnosis reduces complications but is challenged by presentational variability. Computerised Tomography scans (CT) are the preferred diagnostic investigation, offering higher sensitivity and specificity than Ultrasound scans (US). We reviewed AA investigation practice at St Peter’s Hospital (SPH), analysing the utility of CT and US. Method Data for 189 SPH AA patients (16/05/2022-13/01/2023) were collated by age, sex (females: F, males: M), pregnancy testing, urine dip, Clinicians’ judgement, imaging performed, and results. Age parameters were: <18, 18-40, 41-64, 65+. Results 84 F (<18: 11, 18-40: 37, 41-64: 25, 65+: 11) and 105 M (<18: 26, 18-40: 37, 41-64: 31, 65+: 11) were included. 55 F and 52 M had urine dip. Pregnancy testing was performed in 82.0% of applicable F. Judgement was most accurate in 18-40 (M: 94.9%; F: 97.3%). Commonest imaging was US in <18 (F: 5/9 confirming AA; M: 10/13 confirming AA). US-only accuracy was highest for 18-40 (F) and also commonest (24 performed: 16 confirming AA). For 18-40 (M), CT-only were commonest (15 performed, all confirming AA); 11 US performed (6 confirming AA). All F 65+ (11) had CT (all confirming AA); 2 US performed (all inconclusive). All 65+ M (11) had CT (10 confirming AA); 1 US performed (confirming AA). M <65 were more likely (than F) to have no imaging. Conclusions The data indicate a disparity between imaging rates and modality based on sex, age, and accuracy. We will highlight this to SPH for consideration.