The diagnostic value of indirect ultrasound signs during acute adult appendicitis

Abstract

When tomodensitometry cannot be performed and the appendix is not visible on ultrasound examination, indirect ultrasound signs must be systematically sought, particularly in populations in which appendicitis are highly prevalent.

ACR Appropriateness Criteria® Right Lower Quadrant Pain-Suspected Appendicitis

“…US Pelvis. Three retrospective studies of pelvic US were identified with one single-institution study combining transabdominal and transvaginal imaging in 292 women [46] and two multi-institutional studies [47,48] evaluating 573 and 620 male and female patients with iliac fossa US, respectively. Greatest sensitivity of 97.3%, specificity of 91.0%, PPV of 91.7%, and NPV of 97% were achieved when combining transabdominal US and transvaginal US performed by a single experienced operator in adult women (95% CI).…”

“…Greatest sensitivity of 97.3%, specificity of 91.0%, PPV of 91.7%, and NPV of 97% were achieved when combining transabdominal US and transvaginal US performed by a single experienced operator in adult women (95% CI). Nonvisualization of the appendix ranged from 20.3% [48] to 45% [47]. There is wide variability with ranges of sensitivity of 31.8% to 83.9%, specificity of 56.7% to 96.7%, PPV of 25% to 95.8%, and NPV of 57.2% to 83.3% related to presence and combination of clinical and US signs of appendicitis that include pain, hypertrophic fat, and diminished peristalsis [48].…”

“…Nonvisualization of the appendix ranged from 20.3% [48] to 45% [47]. There is wide variability with ranges of sensitivity of 31.8% to 83.9%, specificity of 56.7% to 96.7%, PPV of 25% to 95.8%, and NPV of 57.2% to 83.3% related to presence and combination of clinical and US signs of appendicitis that include pain, hypertrophic fat, and diminished peristalsis [48]. NARs ranged from 8.3% [46] to 38.4% [47].…”

“…US Pelvis. Two multi-institution retrospective studies were identified, which included all patients who had undergone US prior to appendectomy [47,48]. D'Souza et al [47] in a review of 573 adult and pediatric patients (>6 years of age) yielded mean sensitivity and specificity in patients with visualization of the appendix of 81.7% and 53.9%, and total patient population mean values of 51.8% and 81.4%.…”

A Simple Clinical Decision Rule To Rule Out Appendicitis In Patients With Nondiagnostic Ultrasound Results

“…A recent study showed that absence of transducer tenderness in the RLQ and hypertrophy of the peritoneal fat has a NPV of only 66%. 33 Therefore, US only seems not suitable to exclude appendicitis in patients who have strong clinical suspicion of appendicitis based on clinical signs and symptoms.…”