Abstract
BackgroundDetection of metastases can have a significant impact on therapy. Nevertheless, even in gadoxetate disodium-enhanced MR scans, very small hepatic metastases may be difficult to see.PurposeTo investigate the potential of a contrast-optimised (phase-sensitive) inversion recovery MR sequence in gadoxetate disodium-enhanced scans for detection of hepatic metastases.Materials and methodsWith institutional review board approval and after written informed consent, 40 patients (18 male, 22 female) with suspected or known hepatic metastases were examined on a 1.5 T MR system. A T1-weighted gradient-echo volumetric-interpolated-breath-hold (VIBE) sequence was acquired as part of the standard imaging protocol 20 minutes after administration of gadoxetate disodium. Additionally, an IR sequence was acquired with an inversion time to suppress native signal from metastases. Overall image quality and delineation of lesions were assessed on VIBE as well as on magnitude-reconstructed (MAG) and phase-sensitive IR (PSIR) sequences. Lesion-to-liver contrast (LLC) was compared between VIBE and MAG images.ResultsOverall image quality was high in both VIBE and MAG IR sequences (VIBE 4.275; MAG 4.313), yet significantly lower in PSIR (4.038). Subjective delineation of lesions was higher on MAG and PSIR images compared to VIBE in all size groups with an overall statistically significant difference for VIBE vs. MAG vs. PSIR (p < .001) in the variance analysis. Mean LLC was 0.35±0.01 for VIBE sequences, and 0.73±0.01 for MAG.ConclusionContrast-optimised PSIR seems to improve imaging characteristics of hepatic metastases in gadoxetate disodium-enhanced scans compared to T1 gradient-echo VIBE sequences.
Highlights
Due to its rich blood supply, the liver is one of the organs most frequently affected by metastatic disease
Subjective delineation of lesions was higher on MAG and phasesensitive inversion recovery (IR) (PSIR) images compared to VIBE in all size groups with an overall statistically significant difference for VIBE vs. MAG vs. PSIR (p < .001) in the variance analysis
Contrast-optimised PSIR seems to improve imaging characteristics of hepatic metastases in gadoxetate disodium-enhanced scans compared to T1 gradient-echo VIBE sequences
Summary
Due to its rich blood supply, the liver is one of the organs most frequently affected by metastatic disease. Since its approval in Europe and Asia in 2005 and in the United States in 2008, gadoxetate disodium (Gd-EOB-DTPA) has become well established in hepatobiliary imaging due to its property to be taken up by hepatocytes as they express an organic anion transporting peptide. Lesions without the organic anion transporting peptide do not accumulate gadoxetate disodium and appear hypointense in the hepatobiliary phase compared to the enhancing normal liver parenchyma, improving detection rates of liver metastases [1,2,3]. To investigate the potential of a contrast-optimised (phase-sensitive) inversion recovery MR sequence in gadoxetate disodium-enhanced scans for detection of hepatic metastases
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