Simple measurements on diffusion-weighted MR imaging for assessment of complete response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer
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To determine diagnostic performance of simple measurements on diffusion-weighted MR imaging (DWI) for assessment of complete tumour response (CR) after neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (LARC) by signal intensity (SI) and apparent diffusion coefficient (ADC) measurements.
Materials and methods
Sixty-five patients with LARC who underwent neoadjuvant CRT and subsequent surgery were included. Patients underwent pre-CRT and post-CRT 3.0 T MRI. Regions of interest of the highest brightness SI were included in the tumour volume on post-CRT DWI to calculate the SIlesion, rSI, ADClesion and rADC; diagnostic performance was compared by using the receiver operating characteristic (ROC) curves. In order to validate the accuracy and reproducibility of the current strategy, the same procedure was reproduced in 80 patients with LARC at 1.5 T MRI.
Areas under the ROC curve for identification of a CR, based on SIlesion, rSI, ADClesion, and rADC, respectively, were 0.86, 0.94, 0.66, and 0.71 at 3.0 T MRI, and 0.92, 0.91, 0.64, and 0.61 at 1.5 T MRI.
Post-CRT DWI SIlesion and rSI provided high diagnostic performance in assessing CR and were significantly more accurate than ADClesion, and rADC at 3.0 T MRI and 1.5 T MRI.
• Signal intensity (SI lesion ) and rSI are accurate for assessment of complete response.
• rSI seems to be superior to SI lesion at 3.0 T MRI.
• ADC or rADC measurements are not accurate for assessment of complete response.
KeywordsDWI Signal Intensity Complete Response Chemoradiotherapy Locally Advanced Rectal Cancer
Diffusion-weighted MR imaging
Apparent diffusion coefficient
Locally advanced rectal cancer
The scientific guarantor of this publication is Pei-Rong Ding. The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article. This study has received funding by Nature Science Foundation of China [No. 81101591]; Natural Science Foundation of Guangdong Province, China [No.S2011040005278; No.9151008901000157]; Science and Technology Planning Project of Guangdong Province, China [No.2010B060900043]; and Medical Scientific Research Foundation of Guangdong Province, China (WSTJJ20101107440520197505093916). One (Pei-Rong Ding) of the authors has significant statistical expertise. Institutional Review Board approval was obtained. Written informed consent was not required for this study because it is a retrospective analysis. Approval from the institutional animal care committee was not required because the study is not on animals. The study subjects or cohorts have not been previously reported. Methodology: retrospective, diagnostic or prognostic study, performed at one institution.
Pei-Qiang Cai, Yao-Pan Wu and Xin An contributed equally to this work.