Gadoxetic acid-enhanced 3.0 T MR imaging versus multidetector-row CT in the detection of colorectal metastases in fatty liver using intraoperative ultrasound and histopathology as a standard of reference

Objective: To compare the diagnostic value of gadoxetic acid-enhanced MRI at 10 T with 64-row MDCT in the detection of colorectal liver metastases in diffuse fatty infiltration of the liver after neoadjuvant chemotherapy. Methods: Twenty-three patients with colorectal liver metastases and at moderate to severe steatosis (25-90%) underwent prospectively preoperative tri-phasic MDCT (Somatom Sensation 64. Siemens) and gadoxetic acid-enhanced MRI (3-T Magnetom Trio, Siemens). All patients underwent surgical resection of liver metastases. Intraoperative ultrasound (IOUS) was carried out, which served as the standard of reference, together with histopathology. Results: Overall, 68 metastases (range, 0.4-6 cm; 31/68 metastases [46%] <= 1 cm) were found at histology. MDCT detected 49/68 lesions (72%), and MRI 66/68 (97%, p < 0.001). For lesions <= 1 cm, MDCT detected only 13/31 (41.9%) and MRI 29/31 (93%, p < 0.001). Eight false-positive lesions were detected by MDCT, seven small lesions by MRI. There was no statistically significant difference between the two modalities in the detection of lesions >1 cm (p = 0.250). IOUS detected all metastases and revealed two false-positive diagnoses. Conclusion: Gadoxetic acid-enhanced 3.0 T MRI is superior to 64-row MDCT in detecting colorectal liver metastases <= 1 cm during preoperative staging in patients with liver steatosis. A combination of MRI and IOUS may further improve the outcome of surgical treatment. (C) 2012 Elsevier Ltd. All rights reserved.