Akihiro Nishie MD, Presenter: Nothing to Disclose

Yoshiki Asayama MD, Abstract Co-Author: Nothing to Disclose

Yasuhiro Ushijima MD, Abstract Co-Author: Nothing to Disclose

Yukihisa Takayama MD, Abstract Co-Author: Research Grant, Bayer AG Research Grant, Koninklijke Philips Electronics NV

Nobuhiro Fujita MD, PhD, Abstract Co-Author: Nothing to Disclose

Hiroshi Honda MD, Abstract Co-Author: Nothing to Disclose

Dai Shimamoto, Abstract Co-Author: Nothing to Disclose

Osamu Togao MD, PhD, Abstract Co-Author: Nothing to Disclose

Takashi Yoshiura MD, PhD, Abstract Co-Author: Nothing to Disclose

Makoto Obara, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Jochen Keupp PhD, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

To elucidate if chemical exchange saturation transfer (CEST) imaging can predict tumor grade of rectal cancer and to investigate the feasibility of this new MR sequence for predict malignant potential

A total of ten patients with rectal cancer who underwent MR examination including CEST imaging were enrolled. CEST imaging was scanned with single-shot 2D TSE-DRIVE on a 3T clinical scanner (Achieva TX 3.0T, Philips Healthcare, NL) using a 32-channel SENSE Torso/Cardiac coil and 2-channel parallel transmission. The sequence parameters were as follows: Tsat=0.5 s, TR/TE=5000/6 ms, FOV=230 mm2, spatial resolution=1.8×1.8×5 mm3, 25 saturation frequency offsets S[ω], ω = -6.0 to +6.0 ppm (step 0.5 ppm) and S0 (ω=-160 ppm), affording 2 minutes scanning time. ΔB0 correction was also performed. MTR asymmetry (MTRasym) was defined as: MTRasym = {Ssat(−offset)−Ssat(+offset)}/S0, where Ssat and S0 are signal intensities on the images with presaturation pulse at -6.0 to +6.0 ppm and control (160 ppm). The calculated MTRasym map at the offset of 3.5 ppm was generated, and region-of-interests were carefully placed in the entire area of each rectal cancer on this map to measure APT signal (%). Each tumor was also histologically divided into three tumor grades (well-, well- to moderately and moderately differentiated adenocarcinomas). The mean APT signal was compared among the three tumor grades using a Fisher’s least significant difference.

The mean APT signal of well-differentiated adenocarcinoma (n=2; 0.15+/-0.05%) was significantly lower than those of well- to moderately and moderately differentiated adenocarcinomas (n=3; 2.57+/-0.22% and n=5; 2.24+/-0.50%)(p<0.05). There was no significant difference in APT signal between well- to moderately and moderately differentiated adenocarcinomas.

CEST imaging can predict tumor grade of rectal cancer non-invasively.

CEST imaging describes high ability to synthesize protein of cancer and may enable us to quantify tumor malignancy and proliferative potential. APT signal can be a new imaging biomarker of cancer.

Nishie, A, Asayama, Y, Ushijima, Y, Takayama, Y, Fujita, N, Honda, H, Shimamoto, D, Togao, O, Yoshiura, T, Obara, M, Keupp, J, MR Prediction of Tumor Grade in Rectal Cancer Using Chemical Exchange Saturation Transfer Imaging.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13017189.html