It is not recommended for the children if clinical findings are not supporting the presence of appendicitis or unlikely to have appendicitis based on the laboratory tests. Imaging may be helpful to consider or to exclude the diagnosis of appendicitis in children who have atypical findings for appendicitis. It is also recommended in the patients who were on the antibiotic treatment prior to evaluation. It is recommended in the high probability of appendicitis based on the clinical and laboratory findings. 

 

Radio imaging approach: The patients having atypical or equivocal clinical findings for appendicitis, the diagnosis procedure further steps in the radio imaging evaluation. Ultrasound is the first preferred modality. If an appendix is not seen in the US then CT is recommended. If a more prompt diagnosis is required then MRI is recommended. 

 

Ultrasound: The studies have reported US has 98 % specificity and 92% sensitivity. However, the diagnosis of appendicitis cannot be reliably excluded by US unless a normal appendix is seen. The visualization rate is reported between 22 to 98 % in case of US. The technique of the ultrasonography and body habitus of the child are two important responsible factors for the variation in the range of visualization rate. The visualization rate can be improved by following techniques.

 

Posterior compression: The addition of posterior manual compression to graded compression is helpful to identify the appendix. 

 

Positional scanning:In addition to the right lower quadrant, scanning in the flank and pelvis may be useful. Possible findings in US: Following findings indicates the presence of appendicitis. Noncompressible tubular structure in right lower quadrant Wall thickness of the appendix greater than 2 mm Overall diameter greater than 6 mm Free fluid in the right lower quadrant Thickening of the mesentery Localized tenderness with graded compression Presence of a calcified appendicolith Limitations of 

 

US: In overweight children, fat may absorb or diffuse the ultrasound beam. Difficult to differentiate between a normal appendix or one that is only focally inflamed. Pain and/or anxiety may make sonographic imaging of the abdomen difficult or impossible in some children. When appendix is not seen in US, further radio imaging is recommended which is mostly CT. 

 

CT: The sensitivity of CT in the diagnosis of acute appendicitis in children isbetween 94 and 100 percent and reported specificity is 93 to 100%. The intravenous contrast and focused CT can improve the accuracy and safety of the CT. Possible CT findings: Following findings in CT supports the presence of appendicitis. 

 

Wall thickness greater than 2 mm Appendicolith Enlargement of the appendix Concentric thickening of the appendiceal wall Phlegmon Abscess Free fluid Thickening of the mesentery, fat stranding Limitations: A normal appendix is more difficult to visualize in children with less intraperitoneal fat. A fluid-filled loop of small bowel can be misinterpreted as in inflamed appendix An appendicolith may be unclear by intestinal contrast A Meckel's diverticulum can be misdiagnosed as an enlarged appendix. The conditions like Crohn's disease and lymphoma may not be differentiated from appendicitis on CT. 

 

MRI: Studies have reported 98% sensitivity and 97% specificity in the diagnosis of acute appendicitis. MRI with or without contrast may be a suitable alternative to CT in pediatric patients with suspected appendicitis. However, as like CT, MRI is not always absolute. 

 

X-rays: Plain radiographs or X-rays of the abdomen are primarily indicated in suspicious pediatric patients . It helps in confirmation of bowel obstruction or perforation. Except these two advantages X-rays are of little use. They are rarely recommended for diagnosis of appendicitis in children. Sometimes they can show secondary signs in acute appendicitis like a fecalith or suggest alternative diagnosis such as basilar pneumonia. The radio imaging is not at all recommended unless clinical findings or laboratory investigations suggests appendicitis. In such cases, patinet should be first evaluated by surgeon rather than imaging. Whenever radio imaging is necessary, it is recommended that it should be performed as per the imaging protocol. A well-established imaging protocol can result in a significant decrease in the radiation exposure without sacrificing the diagnostic accuracy or clinical output.