ABDOMINAL PSEUDOTUMORS AND SIMULATED LYMPHADENOPATHY IN MRI - DIFFERENTIAL FEATURES WITH THE USE OF RETROGRADE AIR INSUFFLATION

In order to evaluate the contribution of retrograde air insufflation i n decreasing the occurrence of pseudotumor appearance and mimicked lym phadenopathy due to nonair-distended bowel loops, we retrospectively c ompared two groups of magnetic resonance (MR) examinations. In the gro up receiving retrograde air insufflation, 10.8% (67 of 619) of images showed a tumor-like lesion due to nonair-distended bowel loop(s), wher eas in the group not receiving air introduction, a tumor-like lesion w as simulated in 45.6% (140 of 307) of images. Furthermore, a collapsed bowel loop(s) mimicking an enlarged lymph node close to the aorta, in ferior vena cava, or bilateral iliac vessels was found in 9.5% (24 of 252) of images of the latter group, in contrast to only 1.8% (9 of 505 ) of images of the former group. This study shows that retrograde air insufflation greatly reduces the occurrence of pseudotumor appearance and false impression of paraaortic, paracaval, or parailiac lymphadeno pathy secondary to nonair-distended bowel loop(s).