Dual-Energy Spectral in CT Aids in Diagnosis of Acute Gangrenous Appendicitis

November 16, 2018

Imaging confirms or excludes the presence of gangrenous appendicitis with high sensitivity and specificity.

Dual-energy CT with virtual monoenergetic and iodine overlay imaging accurately confirms or excludes the presence of gangrenous appendicitis, according to a study published in the American Journal of Roentgenology.

Researchers from Canada performed a retrospective study to determine if the use of dual-energy spectral techniques in CT can improve accuracy in the diagnosis of acute gangrenous appendicitis.

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A total of 209 patients with a pathologic diagnosis of appendicitis were included in the study. Two board-certified abdominal radiologists reviewed 120-kV simulated images, 40-keV virtual monoenergetic images, and color-coded iodine overlay images.

The results showed 44 patients (21.0%) had histopathologic results positive for gangrenous appendicitis. Other findings were:

Sensitivity100% (44/44)100% (44/44)22.7% (10/44)
Specificity81.2% (134/165)80.0% (132/165)96.4% (159/165)
PPV58.7% (44/75)57.1% (44/77)62.5% (10/16)
NPV100% (134/134)100% (132/132)82.4% (159/193)
Accuracy85.2%84.2%77.5%
Interobserver agreement0.990.990.93

All cases of gangrenous appendicitis had true-positive results of virtual monoenergetic and iodine overlay imaging. There were no false-negative results of virtual monoenergetic or iodine overlay imaging.

The researchers concluded that in cases of suspected appendicitis, dual-energy CT that includes virtual monoenergetic and iodine overlay imaging is accurate for confirming and excluding the presence of gangrenous appendicitis with high sensitivity and specificity.