Could IVIM and ADC help in predicting the KRAS status in patients
with rectal cancer?
Received: 5 December 2017 /Revised: 8 January 2018 / Accepted: 12 January 2018 /Published online: 15 February 2018
European Society of Radiology 2018
Purpose To evaluate the diagnostic potential of DW-MRI relative parameters for differentiation of rectal cancers with different
Kirsten rat sarcoma viral oncogene homologue (KRAS) mutation status.
Methods Fifty-one patients with rectal cancer underwent diffusion-weighted MR imaging with eight b values. ADCs (including
Max-ADC, Min-ADC and Mean-ADC) and IVIM parameters (D, pure diffusion; f, perfusion fraction; D*, pseudodiffusion
coefficient) were respectively calculated by mono- and bi-exponential analysis. Patients were stratified into two groups: KRAS
wild type and mutant. The DW-MRI-derived parameters between the KRAS wild-type group and KRAS mutant group were
compared using the Mann-Whitney U test. Receiver-operating characteristic (ROC) analysis of discrimination between KRAS
wild-type and KRAS mutant rectal cancer was performed for the DW-MRI-derived parameters.
Results Max-ADC, Mean-ADC and D values were significantly lower in the KRAS mutant group than in the KRAS wild-type
group, whereas a higher D* value was demonstrated in the KRAS mutant group. According to the ROC curve, Mean-ADC and
D* values showed moderate diagnostic significance with the AUC values of 0.756 and 0.710, respectively. The cut-off values for
Mean-ADC and D* were 1.43 × 10
/s and 26.58 × 10
Conclusion Rectal cancers had distinctive diffusion/perfusion characteristics in different KRAS mutation statuses. The DW-
MRI-derived parameters, specifically Mean-ADC and D*, show a moderate diagnostic significance for KRAS status.
• Rectal cancers with different KRAS mutation statuses demonstrated distinctive diffusion/perfusion characteristics.
• Max-ADC, Mean-ADC and D values were lower in the KRAS mutant group.
• A higher D* value was demonstrated in the KRAS mutant group.
• IVIM-DW MRI may potentially help preoperative KRAS mutant status prediction.
Keywords Rectal cancer
Magnetic resonance imaging
ADC Apparent diffusion coefficient
CRC Colorectal cancer
D Diffusion coefficient
D* Pseudo-diffusion coefficient
DWI Diffusion-weighted imaging
EGFR Epidermal growth factor receptor
f Perfusion fraction
IVIM Intravoxel incoherent motion
KRAS Kirsten rat sarcoma viral oncogene homologue
MRI Magnetic resonance imaging
NCCN National Comprehensive Cancer Network
ROI Region of interest
ROC Receiver-operating characteristic
TE Echo time
TR Repetition time
TSE Turbo spin echo
Rectal cancer, which accounts for 30-35% ofallcolo-
rectal cancer (CRC) cases, is distinctive from the rest of the
colon, and local recurrence is a major problem for clinical
* Hongliang Sun
Department of Radiology, China-Japan Friendship Hospital, No.2
Yinghua East Street, Chaoyang District, Beijing 100029, China
Philips Healthcare, Beijing 100600, China
European Radiology (2018) 28:3059–3065