Combo ultrasound scoring system deftly diagnoses, rules out appendicitis

Researchers from the surgery and radiology departments at Yale University have developed a clinical-ultrasound scoring system that may be both sensitive and specific enough to preclude the use of CT for patients with suspected appendicitis.

Swathi Reddy, MD, and colleagues describe their work in a study published online April 28 in the Journal of Trauma and Acute Care Surgery.

The authors note that CT’s proven facility for accurately ruling out appendicitis in negative cases—and thus heading off unneeded appendectomy—comes at the cost of exposing the patient to ionizing radiation.

For their study, the team reviewed the records of all patients over 15 years old (n = 300) who presented in the emergency department with appendicitis symptoms and underwent initial ultrasound.

From this data Reddy and colleagues formulated an ultrasound score using odds ratios for appendicitis given various clinical observations. Combining this score with those in the Alvarado system, they recorded final diagnosis by pathology reports.

After excluding patients with evident non-appendicitis pathologies, the researchers found that the appendix was not visualized in 114 included cases (38 percent) and partially visualized in 36 (12 percent).

Some 57 patients (21.3 percent) had an appendectomy. One of these (1.7 percent) did not have appendicitis, while six non-visualized appendicies underwent appendectomy with no negative cases.

Sensitivity and specificity for the sonographic score were 86 percent and 90 percent, respectively.

The combined score yielded 98 percent sensitivity and 82 percent specificity at a score of 6.5 (possible acute appendicitis) and 95 percent sensitivity and 87 percent specificity at a score of 7.5 (probable acute appendicitis).

Confirming their hypothesis, the combined ultrasound and Alvarado score yielded an area under the curve of 97.1—significantly better than either score alone (p = 0.017 and P <0.001 respectively), the authors report.

“Our scoring system based entirely on ultrasound findings was highly sensitive and specific for appendicitis, and it significantly improved when combined with the Alvarado score,” Reddy et al. write. “After prospective evaluation, the combined ultrasound-Alvarado score might replace the need for CT imaging in a majority of patients.”