McPherson Stuart, Jonsson Julie R, Cowin Gary J, O'Rourke Peter, Clouston Andrew D, Volp Andrew, Horsfall Leigh, Jothimani Dinesh, Fawcett Jonathan, Galloway Graham J, Benson Mark, Powell Elizabeth E
Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Ipswich Rd., Woolloongabba, Brisbane, Qld 4102, Australia.
J Hepatol. 2009 Aug;51(2):389-97. doi: 10.1016/j.jhep.2009.04.012. Epub 2009 May 18.
BACKGROUND/AIMS: Currently the diagnosis and severity of hepatic steatosis can be established accurately only by liver biopsy. Previous small studies found that steatosis measured by magnetic resonance spectroscopy (MRS) and imaging (MRI) correlated with histological assessment of liver triglyceride content. However, the accuracy of MRS/MRI for grading the severity of steatosis has not been addressed. The aims of this study were (1) to determine whether MRS and MRI can discriminate grades of steatosis in a large cohort of consecutive patients with a wide spectrum of liver disease aetiology and severity (2) to evaluate the effect of hepatic fibrosis, inflammation and iron on quantitation of intrahepatocellular lipid (IHCL) by these techniques.
Ninety-four sequential patients who underwent percutaneous liver biopsy or liver resection had MRS and MRI (Dixon in phase/out of phase (Dixon IP/OP) and with/without fat saturation (+/-FS) images) to determine IHCL. Histology was used as the reference standard.
Close relationships were observed between the percentage of steatosis estimated by histology and MRS/MRI (r(s)=0.88 p<0.001 for all techniques). However, separate equations were required for the percentage of steatosis to avoid underestimation by imaging for patients with moderate or advanced fibrosis. All techniques had good diagnostic accuracy for mild steatosis (AUROC > or =0.87) as well as moderate/severe steatosis (AUROC > or =0.89). Hepatic inflammation and mild iron deposition (Perls' grade 1 and 2) did not interfere with estimation of steatosis by imaging.
MRS and MRI had good accuracy for grading the severity of steatosis in subjects with liver disease, provided that stage of fibrosis was considered.
背景/目的：目前，肝脂肪变性的诊断及严重程度只能通过肝活检准确判定。既往小型研究发现，通过磁共振波谱（MRS）及成像（MRI）测定的脂肪变性与肝脏甘油三酯含量的组织学评估具有相关性。然而，MRS/MRI对脂肪变性严重程度分级的准确性尚未得到研究。本研究的目的为：（1）确定MRS和MRI能否在一大群病因及严重程度各异的连续性肝病患者中区分脂肪变性的等级；（2）评估肝纤维化、炎症及铁对这些技术定量肝内脂质（IHCL）的影响。
94例接受经皮肝活检或肝切除术的连续患者进行了MRS及MRI检查（同/反相位狄克逊序列（Dixon IP/OP）及有无脂肪抑制（+/-FS）图像）以测定IHCL。组织学检查用作参考标准。
组织学评估的脂肪变性百分比与MRS/MRI之间存在密切关系（所有技术的rs = 0.88，p < 0.001）。然而，对于脂肪变性百分比需要采用不同的公式，以避免对中度或重度纤维化患者成像评估时出现低估。所有技术对轻度脂肪变性（AUROC≥0.87）以及中度/重度脂肪变性（AUROC≥0.89）均具有良好的诊断准确性。肝脏炎症及轻度铁沉积（普鲁士蓝染色1级和2级）不影响成像对脂肪变性的评估。
如果考虑纤维化分期，MRS和MRI对肝病患者脂肪变性严重程度分级具有良好的准确性。
