Detecting Normal Appendix with MRI in Children and Adolescents

A recent study reported in Radiology was conducted to evaluate asymptomatic children and adolescents to determine the rate of detection of the normal appendix with unenhanced MRI.

The study concluded that MRI can be used to detect a normal appendix and exclude appendicitis.

The Study
This study included 40 asymptomatic volunteers who underwent MRI to detect the appendix.

Methodology
The MRI protocol consisted of axial T1-weighted fast spin-echo (SE), axial and coronal T2-weighted fast SE, and axial T2-weighted fat-saturated fast SE sequences.

Two observers interpreted results independently, and coefficients were calculated to evaluate agreement.

The rate of detection was defined as the percentage of times that the appendix was visualized with at least 1 sequence.

Results
The normal appendix was detected by 1 observer in 19 cases (48%) and by the other in 20 cases (50%). The rate of appendix detection after observers reached a consensus was 48% (95% CI, 32% to 64%).

Interobserver agreement for appendix detection was good for most sequences analyzed.

The greatest rate of normal appendix detection was found with the axial T2-weighted fast SE sequence (48%).

Conclusions
The rate of normal appendix detection in children and adolescents with unenhanced MRI was 48%, which is similar to CT, but lower than ultrasonographic detection rates.

Reviewer’s Comments
In the current ALARA (as low as reasonably achievable) radiation climate, continued development of alternatives to CT scan for the diagnosis of appendicitis should be carefully watched.

Author: Benjamin M. Taragin, MD

Reference:
Baldisserotto M, Valduga SG, da Cunha CFJS. MR Imaging Evaluation of the Normal Appendix in Children and Adolescents Radiology. Radiology; 2008;249 (October): 278-284