梯度双回波和三回波技术定量分析肝脏脂肪含量的可行性研究

摘要

Objective:To investigate the value of 3. OT MR gradient dual-echo and triple-echo in quantifying liver fat content compared with biopsy. Methods: Forty-two patients in upcoming liver surgery were divided into 3 groups by BMI (Underweight:BMI< 18. 5kg/m2 , Normal: 18. 5kg/m2 24kg/m2 ) and examined to quantify liver relative lipid content (RLC) in region of interest (ROD with same MR sequence at 3. OT MR scanner for statistical analysis, with biopsy as the reference standard. Results: Li ver fat contents were (6. 2 + 4. 3)%, (18. 8±8. 2)% and (8. 9i4. 3)% for biopsy,gradient dual-echo and triple-echo respectively in all patients. Significant positive correlation was demonstrated between gradient triple-echo and biospy in each BMI group (Underweight: r= 0. 87,P<0. 01 Normal: r = 0. 92,P<0. 01 Overweight: r = 0. 95,P<0. 01 All patients: r=0. 94,P<0. 01). Significant positive correlation was only demonstrated between gradient dual-echo and biospy in normal BMI group (r=0. 66,P<0. 01) while no significant correlation for underweight (P>0. 05) and overweight (P>0. 05) BMI group. Conclusion:Gradient triple-echo is a more feasible method for quantifying liver fat content at 3. 0T MR than gradient dual-echo especially for patients with cirrhosis. As BMI increases,the accuracy of MR gradient triple-echo is raised accordingly.%目的:探讨3.0T MR梯度双回波、三回波技术定量分析肝脏脂肪含量的可行性.方法:前瞻性纳入42例可通过手术获得肝脏病理标本的患者作为研究对象,并按体质指数(BMI)分为体重过轻组(BMI＜18.5 kg/m2,10例)、体重正常组(18.5 kg/m2≤BMI＜24 kg/m2,24例)及体重过重组(BMI≥24 kg/m2,8例)3组.所有患者术前均接受MRI扫描,并计算肝脏兴趣区(ROI)的相对脂肪含量(RLC).以病理学结果(脂肪阳性面积率)为金标准,对梯度双回波、三回波测得的RLC进行统计学分析.结果:42例患者病理学检查、梯度双回波及梯度三回波测得的肝脏RLC分别为(6.2±4.3)％、(18.8±8.2)％及(8.9±4.3)％.体重过轻组:梯度双回波测得的RLC与病理结果间无相关性(P＞0.05),而梯度三回波与之呈正相关(r=0.87,P＜0.01)；体重正常组:梯度双回波及梯度三回波测得的RLC与病理结果间均呈正相关(r=0.66,P＜0.01；r=0.92,P＜0.01)；体重过重组:梯度双回波测得的RLC与病理结果间无相关性(P＞0.05),而梯度三回波与之呈正相关(r=0.95,P＜0.01)；所有患者梯度双回波及梯度三回波测得的RLC与病理结果间均呈正相关(r=0.70,P＜0.01；r=0.94,P＜0.01).结论:3.0T MR梯度双回波技术量化分析肝脏脂肪含量的应用价值有限,而梯度三回波技术是完全可行的,且优于前者；随着BMI的增高,梯度三回波技术测量准确性随之提升.