L. Blomqvist et al., Rectal tumour staging: MR imaging using pelvic phased-array and endorectalcoils vs endoscopic ultrasonography, EUR RADIOL, 10(4), 2000, pp. 653-660
The aim of this study was to compare MR imaging and endoscopic ultrasonogra
phy (EUS) for the local staging of rectal tumours. Forty-nine patients were
examined on a 1.5-T MR unit using either a pelvic phased-array coil (n = 3
7) alone or combined with an endorectal coil (n = 12). Sagittal and axial s
equences with T2-weighted fast spin-echo and axial T1-weighted spin-echo te
chniques were employed The EUS technique was performed using a flexible end
osonoscope. The results were compared with findings at histopathological se
ctioning of the specimen. The T-stage on MR correlated with histopathology
in 32 of 49 patients and on EUS in 29 of 49 patients. The N-stage on MR cor
related with histopathology in 22 of 49 patients and on EUS in 26 of 49 pat
ients. Tumour penetration of the rectal wall was predicted by MR with 86% s
ensitivity and 65% specificity, and by EUS with 89% sensitivity and 33%. sp
ecificity. Preoperative radiotherapy was administered to 40 of the patients
after the examinations which may explain some of the overstaging by MR and
EUS. Three patients with surgically and histopathologically confirmed inva
sion of neighbouring II organs in the pelvis were detected preoperatively o
n MR but none on EUS. Tumour penetration of the rectal wall and local lymph
node metastases cannot accurately be predicted with MR or EUS. Magnetic re
sonance, however, seems to be more useful for preoperative identification o
f clinically occult advanced disease.