Comparison of in-phase and out-of-phase gradient recalled echo T1-weighted pulse sequence for MR imaging of malignant liver masses following administration of paramagnetic gadolinium-chelate

Abstract

Background: The purpose of this study was to compare the performance of in-phase and out-of-phase gradient recalled echo (GRE) pulse sequences on paramagnetic contrast-enhanced magnetic resonance (MR) imaging of malignant liver lesions.

Methods: Fifty patients (27 women, 23 men; mean age = 50 ± 27 years) with known or suspected focal liver lesions, nine of whom had a fatty liver, were examined at 1.5 T before and 60 min after injection of gadobenate dimeglumine at a dose of 0.05 or 0.1 mmol/kg using two GRE techniques: echo time of 2.3 ms (out-of-phase) or 4.6 ms (in-phase). Liver signal-to-noise ratio (SNR) and lesion–liver contrast-to-noise ratio (CNR) were calculated.

Results: In patients with a nonfatty liver, liver SNR increased from 26 ± 9 to 41 ± 17 on in-phase images and from 28 ± 8 to 45 ± 14 on out-of-phase images. In patients with a fatty liver, in-phase images provided significantly higher (p < 0.01) liver SNR than did out-of-phase images predose (34 ± 8 on in-phase vs. 21 ± 8 on out-of-phase) and postdose (44 ± 13 on in-phase vs. 33 ± 14 on out-of-phase). In patients with a nonfatty liver, lesion–liver CNR was similar on in-phase and out-of-phase images, predose and postdose. In patients with fatty liver, lesion–liver CNR was significantly (p < 0.01) lower on out-of-phase images on predose and postdose images.

Conclusion: In-phase GRE imaging is recommended for imaging focal liver lesions on paramagnetic contrast-enhanced MR imaging in patients with fatty infiltration of the liver.