MRI-PDFF图像成功测量肝脏脂肪含量

StephenW

MRI-PDFF images successfully measure liver fat content

Wilman HR, et al. PLoS One. 2017;doi:10.1371/journal.pone.0172921.
February 28, 2017

Measurement of liver fat content by MRI-derived proton density fat fraction images had an overall success rate of 96.4% in a large cohort, according to results of a prospective study.

“More and more studies have shown that incidence of fatty liver disease is increasing worldwide, fueled by the ever-growing rates of obesity,” Louise Thomas, PhD, of the University of Westminster, London, told Healio.com/Hepatology. “Identifying fatty liver disease early is essential, given it can be reversed in many people by simple lifestyle changes such as increased physical activity and calorie restriction.”

Researchers conducted the study using patient data from the UK Biobank imaging enhancement protocol that was acquired between August 2014 and October 2015. The LiverMultiScan Discover software (Perspectum Diagnostics, Oxford, U.K.) was used to create proton density fat fraction (PDFF) images from raw magnetic resonance data.

Of the 4,949 patients initially selected, 4,617 patients had their PDFF successfully calculated. The patient cohort was 53% women, had a median BMI of 26.09 kg/m2 (range, 16.04-48.84 kg/m2), a median age of 62 years (range, 45-73 years) and 95.8% self-reported white ethnicity.

Factors significantly associated with higher liver fat content included sex, age, BMI, high blood pressure, weight gain and diabetes (P < 1.6 × 10–6).

BMI showed a particularly strong association with liver fat content, as 90% of the participants who had PDFF greater than 5.5% also had a BMI greater than 25 kg/m2. In comparison, patients with a BMI less than 25 kg/m2 and no diagnosis of diabetes had much smaller PDFF values at a mean of 1.96%.

Women (median 1.76%) had significantly lower liver fat than men (median 2.58%), which remained so when different age groups were compared between men and women. There was no significant difference in PDFF distribution between any age group of the men, and differences decreased between the men and women the older the age group.

“MRI, and magnetic resonance spectroscopy (MRS), are now considered gold-standards for quantitative fat measurement,” the researchers wrote. “MRI methods rely on pulse sequences, where the combination of different images can give fat and water measurements. MRS is considered the most robust and quantitative of the MR-based methods. It is sensitive and shows good agreement with MRI; however, it is limited by technical demands and availability, and therefore has been applied to relatively small studies in specialist centers.”

According to the researchers, the magnetic resonance sequence takes only 3 minutes or less and requires no contrast. The high success rate on a large cohort produced a population level statistic relevant to epidemiology.

“The results of this study that we have conducted in partnership with Perspectum Diagnostics describes the high incidence of fatty liver disease in the U.K. population; this information gained from this study will be essential for identifying high risk individuals in the future,” Thomas said. “The UK Biobank will be MRI scanning 100,000 people, which provides us with a unique opportunity to look at the factors determining liver fat accumulation in relation to both lifestyle and genetic factors.” – by Talitha Bennett

Disclosure: Thomas reports she has no relevant financial disclosures. Please see the full study for the other researchers’ relevant financial disclosures.

StephenW

MRI-PDFF图像成功测量肝脏脂肪含量

Wilman HR，et al。 PLoS One。 2017年; doi：10.1371 / journal.pone.0172921。
2017年2月28日

根据前瞻性研究的结果，通过MRI衍生的质子密度脂肪分数图像测量肝脏脂肪含量在大型队列中的总体成功率为96.4％。

伦敦威斯敏斯特大学的路易斯·托马斯博士告诉Healio.Hepatology，越来越多的研究表明，脂肪肝疾病的发病率在全世界范围内增加，由于肥胖的不断增长，“Louise Thomas，PhD。 “早期识别脂肪肝疾病是至关重要的，因为它可以通过简单的生活方式改变（例如增加身体活动和热量限制）在许多人中逆转。

研究人员使用在2014年8月至2015年10月之间获得的英国生物库成像增强方案的患者数据进行了研究。使用LiverMultiScan Discover软件（Perspectum Diagnostics，Oxford，UK）从原始图像生成质子密度脂肪部分（PDFF）磁共振数据。

在最初选择的4,949例患者中，4,617例患者的PDFF成功计算。患者队列为53％的女性，中位BMI为26.09kg / m 2（范围，16.04-48.84kg / m 2），中位年龄为62岁（范围45-73岁）和95.8％自我报告的白种人。

与较高的肝脏脂肪含量显着相关的因素包括性别，年龄，BMI，高血压，体重增加和糖尿病（P <1.6×10-6）。

BMI显示与肝脏脂肪含量特别强的关联，因为90％的PDFF大于5.5％的参与者也具有大于25kg / m 2的BMI。相比之下，BMI低于25 kg / m2且无糖尿病诊断的患者的PDFF值小得多，平均为1.96％。

女性（中位数1.76％）的肝脏脂肪明显低于男性（中位数为2.58％），当男性和女性之间比较不同年龄组时，仍然如此。在男性的任何年龄组之间PDFF分布没有显着差异，男性和女性之间的差异降低了年龄组。

“MRI和磁共振波谱（MRS），现在被认为是定量脂肪测量的金标准，”研究人员写道。 “MRI方法依赖于脉冲序列，其中不同图像的组合可以给出脂肪和水的测量。 MRS被认为是基于MR的方法中最稳健和最定量的。它是敏感的，并与MRI有良好的协议;然而，它受到技术需求和可用性的限制，因此已经应用于在专业中心的相对小的研究。

根据研究人员，磁共振序列只需要3分钟或更少，不需要对比度。大型队列的高成功率产生了与流行病学相关的人群水平统计。

“我们与Perspectum Diagnostics合作开展的这项研究的结果描述了英国人群脂肪肝疾病的高发病率;从这项研究中获得的这些信息对于未来识别高风险个体至关重要。“Thomas说。 “英国生物银行将对10万人进行磁共振成像扫描，这为我们提供了一个独特的机会来观察决定肝脏脂肪蓄积与生活方式和遗传因素相关的因素。” - Talitha Bennett

披露：Thomas报告她没有相关的财务披露。请参阅其他研究人员相关财务披露的完整研究。