Appendicitis: evaluation of sensitivity, specificity, and predictive values of US, Doppler US, and laboratory findings.

Abstract

PURPOSE:

To evaluate the sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of ultrasonography (US), Doppler US, and laboratory findings in the diagnosis of appendicitis.

MATERIALS AND METHODS:

A total of 125 consecutive patients suspected of having appendicitis were prospectively included for US appendiceal (diameter enlarged to 6 mm or greater, intraluminal fluid, lack of compressibility) and periappendiceal (periileal inflammatory changes, cecal wall thickening, periileal lymph nodes, peritoneal fluid) evaluation, Doppler US evaluation (appendiceal wall signal), and laboratory assessment (leukocytosis, C-reactive protein [CRP]). Definite diagnoses were established at surgery in 61 patients, at endoscopy with biopsy in two patients, and at clinical follow-up in 62 patients.

RESULTS:

The prevalence of appendicitis was 46%. The appendix was identified with US in 86% of the patients, which included 96% of patients with and 72% of patients without appendicitis. The most accurate appendiceal finding for appendicitis was a diameter of 6 mm or larger, with a sensitivity, specificity, NPV, and PPV of 98%. The lack of visualization of the appendix with US had an NPV of 90%. The most accurate periappendiceal finding of appendicitis was the presence of inflammatory fat changes, with an NPV of 91% and a PPV of 76%, whereas other findings had both NPV and PPV less than 65%. An increase in both white blood cell (WBC) count and CRP level had a PPV of 71%, whereas combined normal WBC count and CRP value had an NPV of 84%.

CONCLUSION:

A threshold 6-mm diameter of the appendix under compression is the most accurate US finding for appendicitis and has high NPV and PPV.

• Authors: Nicolas Kessler, Catherine Cyteval, Benoît Gallix, Alvian Lesnik, Paul-Marie Blayac, Joseph Pujol, Jean-Michel Bruel, Patrice Taourel
• Journal: Radiology (Radiology) Vol. 230 Issue 2 Pg. 472-8 (Feb 2004) ISSN: 0033-8419 [Print] United States
• PMID: 14688403 (Publication Type: Comparative Study, Journal Article)
• Copyright: Copyright RSNA, 2003

Chemical References

• C-Reactive Protein

Topics

• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Appendectomy
• Appendicitis (diagnostic imaging, pathology, physiopathology, surgery)
• Appendix (blood supply, pathology)
• Blood Flow Velocity (physiology)
• C-Reactive Protein (analysis)
• Diagnosis, Differential
• Female
• Humans
• Image Processing, Computer-Assisted
• Leukocyte Count
• Male
• Middle Aged
• Predictive Value of Tests
• Prospective Studies
• Sensitivity and Specificity
• Ultrasonography, Doppler