The value of intravoxel incoherent motion and diffusion kurtosis imaging in the assessment of tumor regression grade and T stages after neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer. Issue 136 (March 2021)

• Record Type: Journal Article
• Authors: Yang, Lanqing; Xia, Chunchao; Zhao, Jin; Zhou, Xiaoyue; Wu, Bing
• Is Part Of: European journal of radiology. Issue 136(2021)
• Publication Date: 2021-03
• Subjects: ADC apparent diffusion coefficient -- DWI diffusion-weighted imaging -- DKI diffusion kurtosis imaging -- IVIM intravoxel incoherent motion imaging -- LARC locally advanced rectal cancer -- nCRT neoadjuvant chemoradiotherapy -- pCR pathologic complete response -- TME total mesorectal excision -- TRG tumor regression grade; Rectal neoplasms -- Neoadjuvant therapy -- Diffusion magnetic resonance imaging; Medical radiology -- Periodicals; Radiology -- Periodicals; Radiologie médicale -- Périodiques; Medical radiology; Periodicals; 616.075705
• DOI: 10.1016/j.ejrad.2020.109504
• Languages: English
• ISSNs: 0720-048X

Abstract

Highlights: The mean diffusivity (MD) values after neoadjuvant chemoradiotherapy (nCRT) were especially useful to identify pathological complete response (pCR), with the highest AUC and were more sensitive than the ADC values % vs. 77.1. The perfusion fraction (f) values could provide additional information on the selection of patients with pCR. pre- and post-CRT MD values were significantly associated with ypT stages. Abstract: Purpose: To evaluate the role of IVIM and diffusion kurtosis imaging (DKI) in identifying pathologic complete response (pCR) and T stages after neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC). Method: Forty-two patients with biopsy-proven rectal adenocarcinoma, who underwent both pre-and post-CRT MRI with IVIM and DKI sequences on a 3 T scanner, were enrolled prospectively. According to the pathologic ypTNM stages and tumor regression grade (TRG), patients were grouped into pCR (TRG0) and non-pCR (TRG1−3) groups and low T stage (ypT0−2) and high T stage (ypT3−4) groups. IVIM parameters (the slow diffusion coefficient [D], fast diffusion coefficient [D*], perfusion fraction [f]), DKI parameters (mean diffusivity [MD] and mean kurtosis [MK]), and mono-exponential ADC were calculated and analyzed between groups. Results: The pCR group had significantly higher post-CRT ADC, D*, f, and MD values than non-pCR group, and higher percent changes in the ADC, f, and MD values (all P < 0.05). The post-CRT MD values yielded the highest AUC (0.788) with higher sensitivity than post-ADC values (82.9 % vs. 77.1 %, respectively). Post-CRT ADC and MD values and the percent changes in the ADC and MD values were also negatively correlated with TRG (all P < 0.05). Besides, negative correlations were found among the pre-CRT MD, post-CRT ADC, D, f, and MD values and the ypT stages (all P < 0.05). Conclusions: Both IVIM and DKI parameters could provide more information when evaluating pCR and T stages after nCRT. In particular, the diagnostic performance of the MD values was more valuable than ADC values in being able to determine pCR.