MR Imaging of acute appendicitis in children

Acute appendicitis is the most common cause of acute abdominal pain requiring
surgery in children, and typically occurs in older children and young adults.
The main cause of appendicitis is obstruction of the appendiceal lumen that
leads to diminished lymphatic and venous drainage, which in turn can result in
bacterial infection of the appendiceal wall.
Appendicitis presents with periumbilical pain typically descending to the right
lower quadrant, as well as nausea and vomiting in 50% of the patients. If
presentation is less specific, it can be difficult to differentiate acute
appendicitis from other sometimes non-surgical conditions that result in acute
abdominal pain. In these cases, additional imaging is necessary to avoid delay
of diagnosis or unnecessary surgical intervention. The main complication of a
delayed diagnosis is perforation, which can lead to abscess formation,
peritonitis, and even death. The prevalence of appendiceal perforation in
various pediatric series ranges from 23% to 73%. Graded-compression US is the
imaging method of choice, and high sensitivity and specificity can be achieved
when employed by experienced examiners. However, the appendix is not always
visible, especially if the appendix has a retrocoecal location or if the
appendix is perforated. When further evaluation is necessary, other imaging
modalities play an important role in diagnosis. CT examination in appendicitis
has been validated and the number of CT scans performed in the presurgical
diagnosis of appendicitis is increasing rapidly. However the lifetime risk of
radiation-induced fatal cancer is estimated to be considerably higher for
fetal, pediatric and adolescent exposure than for adult exposure. There are
several publications describing good results with MR imaging of appendicitis in
adults, mainly involving pregnant patients. However pediatric patients have a
different constitution (in general less abdominal fat and the imaging
characteristics of the appendix may be different (because of lymphoid tissue).
As far as we know no prospective studies have been done in children, even
though this population may benefit the most from this technique. One of the
reasons for this may be that up to recently the examination time was long,
resulting in motion artifacts. The introduction of ultra-fast sequences
shortens the examination time, resulting in less motion artifacts, which is
especially useful in children.

To determine the value of MRI in a consecutive series of pediatric patients
suspected for acute appendicitis

This will be a prospective study performed at the department of Radiology of
the Medical Center Alkmaar. 100 consecutive pediatric patients suspected of
appendicitis will undergo ultrasound and MR Imaging.

There is no burden or risk with participation of the study.