ENDOSONOGRAPHIC AND COLOR DOPPLER FLOW IMAGING ALTERATIONS OBSERVED WITHIN IRRADIATED RECTAL-CANCER

Purpose: To correlate the endosonographic and color Doppler Bow imagin g alterations observed in irradiated rectal cancers with the pathologi c features of radiation response, and to evaluate the potential impact of altered blood flow on the integrity of the surgical anastamosis. M ethods and Materials: Endosonography with color and pulsed wave Dopple r was performed on 20 rectal cancer masses before and after high dose preoperative radiation (XRT), Pre- and post-XRT observations included comparing alterations in tumor size, sonographic echotexture, color Do ppler flow, and pulsatility indices, Comparisons were made with pathol ogic findings in the irradiated specimens and with the incidence of an astomotic failure. Results: Compared to pre-XRT observations, irradiat ed rectal cancers decreased in size and became either mixed in echogen icity with less apparent color Doppler flow (16 of 20) or unchanged in color Doppler flow and echotexture (4 of 20), Those with less Bow (16 of 20) were imaged later (mean = 90.2 +/- 12.1 days) than those witho ut change in color Doppler Row (mean = 21.7 +/- 2.7 days), Pathologica lly, the group of four without change in color Doppler signal had feat ures of acute inflammation which were not observed in 16 of 20 imaged later, Based on pulsatility index measurements, both high and low resi stance vessels were detected and confirmed by immunohistochemical stai ning, and features of postradiation obliterative vasculitis were obser ved, Only one primary anastomosis in 14 patients with decreased flow f ailed. Conclusions: The sonographic and color Doppler Bow imaging alte rations observed within irradiated rectal cancer correlated with chang es of postradiation obliterative vasculitis, The apparent diminished l ocal blood flow within high and low resistance vessels post-XRT did no t result in an increased incidence of anastomotic failures.