On the Role of Ultrasonography and CT Scan in the Diagnosis of Acute Appendicitis

Abstract

The purposes of this study were to revisit the utility of ultrasonography (USG) as a primary imaging modality in acute appendicitis (AA) and to establish the role of CT scan as a second-line/problem-solving modality. All cases of suspected AA were referred for urgent USG. USG was done with standard protocol for appendicitis. Limited computed tomographic (CT) scan [NCCT ± CECT (IV contrast only)] was done for the lower abdomen and pelvis where sonographic findings were equivocal. One hundred and twenty-one patients were referred for USG for suspected appendicitis. Eight-four patients underwent surgery for AA based on clinical as well as imaging findings, of whom 76 had appendicitis confirmed at histopathology. Three patients were misdiagnosed (3.6 %) on USG as appendicitis. Of 76 patients of appendicitis confirmed histopathologically, 63 (82.8 %) had features of appendicitis on USG and did not require any additional imaging modality. Of 121 patients, 12 (10 %) needed CT scan because of atypical features on USG. Of these 12 patients, seven had retrocecal appendicitis, and three high-up paracolic appendicitis. USG alone had sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of 81, 88, 92.6, 71.6, and 83 %, respectively. When combined with CT scan in select cases, the sensitivity, specificity, PPV, NPV, and accuracy of combined USG + CT scan were 96 % (P 00.0014), 89 %, 93 %, 93.5 % (P00.0001), and 93 % (P00.0484), respectively. Twentyeight (23 %) patients were given alternative diagnosis on USG. Dedicated appendiceal USG should be used as a primary imaging modality in diagnosing or excluding AA. Appendiceal CT can serve as a problem-solving modality.

A different view of the sonographic classification of the appendix

“…However, even to experienced sonographers, the normal vermiform appendix is not always visible sonographically. A US has a sensitivity of 81%, specificity of 88%, positive predictive value (PPV) of 92.6%, negative predictive value (NPV) of 71.6% and accuracy of 83% to detect acute appendicitis [15], similar results have been found in some other studies [16][17][18]. These ratios are higher in pathologic appendices [13].…”

“…The normal appendix can be identified in 67-100% of patients without appendicitis who undergo CT. During sonography, the normal appendix is less frequently visualized, with results varying between 0% and 82%, reflecting the operator dependency of US [19,20]. However, CT has the disadvantage of subjecting the patient to unnecessary doses of radiation [15,21]. Any improvement in the detection of the appendix with US is therefore important for reducing the radiation dose.…”

A New And Early Marker In Diagnosis Of Acute Complicated Appendicitis: Immature Granulocyte

“…AA is the most common reason for emergency abdominal surgery all around the world. [1] Laboratory tests, scoring systems and imaging methods are used in AA diagnosis, as well as the clinical history and physical examination. [19] However, it is not always possible to make a final and accurate diagnosis.…”

“…Acute appendicitis (AA) is the most frequent cause of acute abdominal pain and typically requires emergency surgical intervention; an appendectomy is the most frequently performed emergency operation. [1] Almost 8% of the general population in Western countries will undergo an appendectomy during their lifetime. [2] Most AA cases are simple appendicitis (SA) without complications.…”

The role of inflammatory markers in decreasing negative appendectomy rate: a study based on computed tomography findings

“…[1] Diagnosis is usually based on the combination of initial clinical and laboratory evaluation with imaging modalities. Clinical symptoms include periumbilical pain migrating to the right lower quadrant, nausea, and vomiting, but unfortunately, a clear clinical picture consistent with AA is found in only 50%-60% ing laboratory, surgery, pathology, and discharge summary was performed for each patient.…”