MNDPDP AS A NEGATIVE HEPATIC CONTRAST AGENT - EVALUATION OF STIR IMAGING COMPARED WITH T1-WEIGHTED SE AND GE TECHNIQUES

Our goal was to assess the utility of manganese dipyridoxyl diphosphat e (MnDPDP) as a negative hepatic contrast agent in short inversion tim e IR MRI (STIR). Twenty patients with focal liver lesions (15 with met astatic disease, 5 with hemangiomas) underwent MRI (T1-weighted SE, br eath-hold GE, and STIR sequences) before and after infusion of MnDPDP (5 mu mol/kg). We then compared the results obtained with each sequenc e for hepatic parenchymal enhancement, lesion-to-liver contrast-to-noi se ratio (C/N) measurements, and the number of focal liver lesions obs erved in pre-and postcontrast images. Hepatic enhancement values of 25 .3 +/- 9.7 and 33.6 +/- 2.7% (mean +/- SEM) were obtained for the T1-w eighted SE and GE sequences, respectively. The STIR sequence showed 78 .9 +/- 2.1% negative enhancement (decrease of parenchymal signal inten sity). Although a significant (p < 0.0001) C/N increase was seen after MnDPDP administration for all sequences, STIR showed the highest incr ease (149.0 +/- 25.5%) compared with T1-weighted SE (58.5 +/- 12.7%) a nd GE (83.3 +/- 7.2%) sequences. Similarly, more lesions for all seque nces were detected, but again STIR showed the greatest postcontrast in crease (29.0%). MnDPDP is an effective hepatic contrast agent. As both the negative hepatic enhancement and the increase in lesion-to-liver CIN were superior with the STIR sequence when compared with the positi ve enhancement and CIN values produced by the T1-weighted sequences, i t should be considered for inclusion in the imaging protocol for patie nts with focal liver disease.