Diagnostic accuracy of portal-phase CT and MRI with mangafodipir trisodium in detecting liver metastases from colorectal carcinoma

Abstract

To compare the diagnostic accuracy of single section spiral computed tomography (CT) and magnetic resonance imaging (MRI) with tissue-specific contrast agent mangafodipir trisodium (MnDPDP) in the detection of colorectal liver metastases. One hundred and twenty-five consecutive patients undergoing surgery for primary and/or metastatic disease were evaluated using CT (5 mm collimation and reconstruction interval, pitch 2), two-dimensional fast spoiled gradient echo (2D FSPGR) T1 and single shot fast-spin echo (SSFSE) T2 weighted breath-hold MRI sequences, performed before and after intravenous administration of MnDPDP. The reference standards were intraoperative ultrasound and histology. The per-patient accuracy of CT was 72.8 versus 78.4% for unenhanced MRI (p = 0.071) and 82.4% for MnDPDP-enhanced MRI (p = 0.005). MnDPDP-enhanced MRI appeared to be more accurate than unenhanced MRI but this was not significant (p = 0.059). The sensitivity of CT was 48.4% versus 58.1% for unenhanced MRI (p = 0.083) and 66.1% for MnDPDP-enhanced MRI (p = 0.004). The difference in specificity between procedures was not significant. The per-lesion sensitivity was 71.7, 74.9 and 82.7% for CT, unenhanced MRI, and MnDPDP-enhanced MRI, respectively; the positive predictive value of the procedures was respectively 84.0, 96.0 and 95.8%. MnDPDP-enhanced MRI provided a high level diagnostic confidence in 92.5% of the cases versus 82.5% for both unenhanced MRI and CT. The kappa value for inter-observer variability was >0.75 for all procedures. The diagnostic accuracy and sensitivity of MnDPDP-enhanced MRI is significantly higher than single section spiral CT in the detection of colorectal cancer liver metastases; no significant difference in diagnostic accuracy was observed between unenhanced MRI and MnDPDP-enhanced MRI.