Detection of focal hepatic lesions: Comparison of unenhanced and SHU 555 A-enhanced MR imaging versus biphasic helical CTAP

The purpose of this study was to compare the diagnostic sensitivity of unen hanced magnetic resonance (MR) imaging, and MR imaging with a new superpara magnetic iron oxide (SPIO)-enhanced contrast agent (SHU 555 A) with biphasi c helical computed tomography during arterial portography (CTAP) in patient s with focal liver lesions. Eighteen patients with a total of 91 (78 malign ant, 13 benign) proven liver lesions underwent unenhanced short tau inversi on recovery (STIR), T2-weighted (T2-w) TSE, and SHU 555 A-enhanced T2-w tur bo spin-echo (TSE) MR imaging and biphasic helical CTAP. The standard of re ference was histopathologic analysis of resected specimens in 59 lesions, i ntraoperative ultrasound with biopsy in 20 lesions, and CT-guided biopsy an d follow-up in 12 lesions. Diagnostic performance of the imaging modalities was compared quantitatively and qualitatively by assessing lesion Involvem ent in liver segments. There were 68 lesions detected on unenhanced T2-w TS E, which resulted in a sensitivity of 75%. With the STIR sequence, 76 lesio ns were detected, for a sensitivity of 84%, and with SHU 555 A-enhanced AM, 84 lesions were detected, for a sensitivity of 92%. CTAP detected 88 lesio ns, for a sensitivity of 97%. The accuracy for unenhanced T2-w TSE was 98%, for STIR 99%, for enhanced-NM 100%, and for CTAP 95%. The specificity was 100% for SHU 555 A-enhanced MRI and 95% for CTAP. SHU 555 A-enhanced MRI wa s superior to nonenhanced MRI (P < 0.05) and equivalent to CTAP in terms of sensitivity. Due to the absence of false-positive results on SHU 555 A-enh anced MRI, the specificity and accuracy of enhanced MRI were higher than th ose of CTAP, but the difference was not statistically significant (P = 0.13 4). J. Magn. Reson. Imaging 2000;11:665-672. (C) 2000 Wiley-Liss, Inc.