In another study, 84% of cases with noninflamed appendix showed luminal filling when positive oral contrast reaches the cecum, thus excluding diagnosis of appendicitis with high certainty. Therefore, the use of positive oral contrast may augment diagnostic accuracy and confidence in cases of suspected acute appendicitis. No appendix filling with contrast was noted in proven acute appendicitis cases [53]. Diluted oral contrast with 1-hour or 3-hour regimens has a similar diagnostic performance [54]. Nevertheless, no difference was found in the sensitivity, specificity, or average interpretation time when neutral oral contrast was administered compared with positive oral contrast [55]. Single-institution randomized trials showed that low-dose CT was noninferior to standard-dose CT in regard to the negative appendectomy rate, the appendiceal perforation rate, or the proportion of patients needing additional imaging tests [56,57]. CT Abdomen and Pelvis Without IV Contrast CT of the abdomen and pelvis without IV contrast remains a useful tool for the diagnosis of appendicitis. Evaluation for appendicitis with a nonenhanced CT was shown to be conclusive in up to 75% of cases in a study of 536 patients, with a reported sensitivity, specificity, PPV, and NPV of 90%, 96%, 84.8%, and 97.4%, respectively. However, in the 132 (25%) inconclusive cases (ie, no definitive diagnosis of appendicitis or normal appendix), the initial noncontrast CT study was followed by contrast-enhanced CT with a sensitivity, specificity PPV, and NPV of 95.6%, 92.3%, 73%, and 99%, respectively [58]. MRI Abdomen and Pelvis Without and With IV Contrast There is no relevant literature to support the use of MRI abdomen and pelvis without and with IV contrast as the initial imaging modality for the evaluation of acute pelvic pain. However, MRI can be useful for equivocal cases of appendicitis and renal obstruction.
Acute Pelvic Pain in the Reproductive Age Group. In another study, 84% of cases with noninflamed appendix showed luminal filling when positive oral contrast reaches the cecum, thus excluding diagnosis of appendicitis with high certainty. Therefore, the use of positive oral contrast may augment diagnostic accuracy and confidence in cases of suspected acute appendicitis. No appendix filling with contrast was noted in proven acute appendicitis cases [53]. Diluted oral contrast with 1-hour or 3-hour regimens has a similar diagnostic performance [54]. Nevertheless, no difference was found in the sensitivity, specificity, or average interpretation time when neutral oral contrast was administered compared with positive oral contrast [55]. Single-institution randomized trials showed that low-dose CT was noninferior to standard-dose CT in regard to the negative appendectomy rate, the appendiceal perforation rate, or the proportion of patients needing additional imaging tests [56,57]. CT Abdomen and Pelvis Without IV Contrast CT of the abdomen and pelvis without IV contrast remains a useful tool for the diagnosis of appendicitis. Evaluation for appendicitis with a nonenhanced CT was shown to be conclusive in up to 75% of cases in a study of 536 patients, with a reported sensitivity, specificity, PPV, and NPV of 90%, 96%, 84.8%, and 97.4%, respectively. However, in the 132 (25%) inconclusive cases (ie, no definitive diagnosis of appendicitis or normal appendix), the initial noncontrast CT study was followed by contrast-enhanced CT with a sensitivity, specificity PPV, and NPV of 95.6%, 92.3%, 73%, and 99%, respectively [58]. MRI Abdomen and Pelvis Without and With IV Contrast There is no relevant literature to support the use of MRI abdomen and pelvis without and with IV contrast as the initial imaging modality for the evaluation of acute pelvic pain. However, MRI can be useful for equivocal cases of appendicitis and renal obstruction.