肝臓手術におけるMRIの役割とリスク

タイトル: Liver Intrinsic Function Evaluation (LIFE): Multi-parametric Liver Function Profiles of Patients Undergoing Hepatectomy

概要: Background & AimsFor a range of liver malignancies, the only curative treatment option may be hepatectomy, which may have fatal complications. Therefore, an unbiased pre-operative risk assessment is vital, however, at present the assessment is typically based on global liver function only. Magnetic resonance imaging (MRI) modalities have the possibility to aid this assessment, by introducing additional characterization of liver parenchymal, such as non-invasive quantification of steatosis, fibrosis, and uptake function, both for global and regional assessment. To this cause, we here present a prospective observation study (LIFE), in which patients underwent extensive MR-examinations both before and after resective-surgery. Approach and ResultsA total of 13 patients undergoing hepatectomy underwent a pre- (n=13) and post (m=5) multimodal MRI examination (within 3-5 days of the surgery) (Fig. 1B). The multimodal MR-examination included DCE, 3D-MRE, fat fraction measurements (PDFF by MRS, 6PD). Using these measurements, we also construct individual patient profiles by including conventional functional, and volumetric measurements, into a multi-parametric space. As a proof of concept, the areas of each profile, denoted multiparametric profile area (MPA, and aMPA) were calculated, to create a measurement comprising information from all modalities. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=165 SRC="FIGDIR/small/24302306v1_fig1.gif" ALT="Figure 1"> View larger version (35K): [email protected]@2eb05eorg.highwire.dtl.DTLVardef@13d1057org.highwire.dtl.DTLVardef@1fbf9d5_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 1:C_FLOATNO Study-design and the multi-modal magnetic resonance imaging (MRI) examination. (A) Multi-modal MR-protocol and conventional function test. The examination can be divided into five segments. The first segment (dark green box) was the elastography (MRE) at 33 Hz vibration frequency, measuring tissue stiffness. The second segment (teal) was dynamic contrast enhanced (DCE) MRI using the hepatocyte specific contrast agent gadoxetic acid (Gd-EOB-DTPA, Primovist, Bayer Schering Pharma, Berlin, Germany). The third box (light green) was quantitative MRI. Fat fraction via both spectroscopy (MRS) and 6-Point Dixon imaging (6PD). Also, the liver iron content (LIC) was estimated using the relaxation rate R2* obtained via standard T2-weighted imaging. We also performed laboratory function tests including galactose breath test (GBT), Indocyanine Green retention rate (R15) and disappearance rate (PDR), as well as measured bilirubin and albumin. (B) Study setup. A total of 13 patients, all undergoing hepatectomy, underwent a multi-modal MRI examination 3-5 days before and after surgery. A total of five patients were able and willing to undergo the post-surgery MRI examination. C_FIG At a group-level, no clear pattern emerged of MPA or aMPA between groups with different extent of resection. In contrast, on a case-by-case basis, several parameters contributed to high individual MPA or aMPA-values, suggesting tissue abnormalities. With respect to regional DCE measurements, i.e., relative enhancement at 20 minutes, a clear variation between function in segments, within and between the individuals, was observed. ConclusionsIn this combined pre- and post-observational case-based study ranging from very extensive (i) liver surgery to minor (ii), or none (iii), we aimed to describe how a multi-modal MRI examination before hepatectomy could yield valuable information for the pre-operative assessment, with a particular focus on a Couinaud-segmental level. The use of a multi-modal approach allows for a broad spectral characterization of several aspects of the remnant tissue. However, the effectiveness and clinical benefit of each parameter, and how to further optimize an abbreviated clinical MR-protocol needs to be confirmed.