Lesion detection performance of an abbreviated gadoxetic acid-enhanced MRI protocol for colorectal liver metastasis surveillance.

objectiveTo assess the lesion detection performance of an abbreviated MRI (AMRI-M) protocol consisting of ultrafast SE T2W, DWI, and T1W-HBP at 20 min for colorectal liver metastasis (CRLM) surveillance.

methodsIn this Institutional Review Board (IRB)-approved retrospective study, gadoxetic acid-enhanced MRI scans of 57 patients (43 with pathologically proven CRLMs) were assessed. Two readers independently evaluated two sets of images per patient and commented on the number, location, and size of liver lesions. Set 1 included ultrafast spin-echo (SE) T2-weighted (T2W) + T1-weighted (T1W) hepatobiliary phase (HBP) at 20 min sequences + diffusion-weighted imaging (DWI), and set 2 consisted of the standard MRI protocol. A maximum of 10 lesions per patient were recorded. Cohen's kappa analysis, sensitivity, areas under the curve (AUCs), and the MRI cost analysis of the AMRI-M protocol were assessed.

resultsBetween 198 and 209 lesions were assessed with each set of images. The inter-observer agreement for the abbreviated protocol was reported excellent (κ = 0.91). The sensitivity and AUCs for the lesion characterization of AMRI-M protocol were very high (over 90%) for both readers. No statistically significant differences in sensitivity (assessed by mixed-effects logistic regression) and AUCs for lesion characterization (by ROC regression) were found between both protocols. The AMRI-M acquisition time was estimated to be less than 10 min, which translated into 59% cost of standard MRI.

conclusionOur proposed AMRI-M protocol (ultrafast SE T2W, DWI, and T1W-HBP at 20 min) is fast, low-cost alternative to the standard MRI protocol and has a high lesion detection performance. KEY POINTS: • Gadoxetic acid-enhanced protocol has increased the accuracy, sensitivity, and specificity of MRI for detecting colorectal liver metastases. • Our proposed abbreviated MRI protocol is fast, low-cost alternative compared with the standard MRI protocol and has a high lesion detection performance. • Adoption of our protocol may translate to substantial savings for patients and payers.