However, US could be used to confirm the diagnosis of acute appendicitis in this population and to exclude other processes US Abdomen US may be performed in selected high-risk patients to confirm the diagnosis of appendicitis, but US is likely not needed in all high-risk patients, and false-negative results are more common in this population [58]. US Pelvis There are no data regarding the performance of pelvic US as a first-line imaging modality for acute appendicitis. In peri- or postmenarchal girls, a pelvic US may identify alternative causes of pelvic pain [52]. CT Abdomen and Pelvis There is no evidence to support routine use of CT of the abdomen and pelvis or of focused CT in high-risk patients. Based on high sensitivity and specificity, CT could be used to confirm the diagnosis of acute appendicitis in these patients and to exclude other processes that clinically mimic appendicitis. Tan et al [14] showed that in a population of adult and adolescent patients, the positive likelihood ratio for CT was no different from clinical scoring in patients with a high-risk clinical score, suggesting no diagnostic benefit of CT in this context. There are no studies that compare unenhanced and contrast-enhanced CT for diagnosis of acute appendicitis [38,39]. MRI Abdomen and Pelvis There is no evidence to support routine use of MRI in high-risk patients. Based on high sensitivity and specificity that is similar to CT, MRI could be used to confirm the diagnosis of acute appendicitis in high-risk patients and to exclude other processes that clinically mimic appendicitis. However, the diagnostic benefit of MRI in this context has not been demonstrated. Variant 4: Child. Suspected acute appendicitis, equivocal or nondiagnostic right lower quadrant ultrasound. Next imaging study. The definition of an equivocal or nondiagnostic US for acute appendicitis varies widely in the literature, and careful definition of this category has major implications on imaging utilization [22,59,60].
Suspected Appendicitis Child. However, US could be used to confirm the diagnosis of acute appendicitis in this population and to exclude other processes US Abdomen US may be performed in selected high-risk patients to confirm the diagnosis of appendicitis, but US is likely not needed in all high-risk patients, and false-negative results are more common in this population [58]. US Pelvis There are no data regarding the performance of pelvic US as a first-line imaging modality for acute appendicitis. In peri- or postmenarchal girls, a pelvic US may identify alternative causes of pelvic pain [52]. CT Abdomen and Pelvis There is no evidence to support routine use of CT of the abdomen and pelvis or of focused CT in high-risk patients. Based on high sensitivity and specificity, CT could be used to confirm the diagnosis of acute appendicitis in these patients and to exclude other processes that clinically mimic appendicitis. Tan et al [14] showed that in a population of adult and adolescent patients, the positive likelihood ratio for CT was no different from clinical scoring in patients with a high-risk clinical score, suggesting no diagnostic benefit of CT in this context. There are no studies that compare unenhanced and contrast-enhanced CT for diagnosis of acute appendicitis [38,39]. MRI Abdomen and Pelvis There is no evidence to support routine use of MRI in high-risk patients. Based on high sensitivity and specificity that is similar to CT, MRI could be used to confirm the diagnosis of acute appendicitis in high-risk patients and to exclude other processes that clinically mimic appendicitis. However, the diagnostic benefit of MRI in this context has not been demonstrated. Variant 4: Child. Suspected acute appendicitis, equivocal or nondiagnostic right lower quadrant ultrasound. Next imaging study. The definition of an equivocal or nondiagnostic US for acute appendicitis varies widely in the literature, and careful definition of this category has major implications on imaging utilization [22,59,60].