Background

To determine the utility of single-contrast-bolus hepatic extracellular volume (ECV) fraction measurement at different time points to detect and quantify hepatic fibrosis.

Methods

Different grades of liver fibrosis were induced in 23 male Sprague-Dawley rats by carbon-tetrachloride (CCl₄) intoxication. In ten control rats, no fibrosis was induced. Native T1 values and ECV fraction were assessed by using quantitative magnetic resonance imaging (MRI) mapping; only one contrast bolus was applied (gadobutrol 0.1 mmol/kg). ECV values were determined 5, 15, and 25 min after injection. Hepatic fibrosis was quantified histologically by Sirius red staining.

Results

For the 8-week-CCl₄ group, the ECV fraction values obtained 5 (23.5 ± 4.8%, mean ± standard deviation), 15 (23.6 ± 4.8%), and 25 min (23.7 ± 4.7%) after injection were constant over time (p = 0.998); constant data 5–25 min after injection were also observed for the 16-week-CCl₄ group and controls. Liver ECV after 15 min significantly increased with the severity of fibrosis: 18.0 ± 3.0% (controls) versus 23.6 ± 4.8% (8-week-CCl4) versus 30.5 ± 3.3% (16-week-CCl4) (p < 0.001). ECV values after 5, 15, and 25 min significantly correlated with Sirius red staining (p < 0.001 for all parameters).

Conclusions

Hepatic ECV obtained using a single-contrast-bolus technique can be measured 5, 15, and 25 min after injection, obtaining constant values over time, each of them being suitable to detect diffuse hepatic fibrosis. In clinical practice, post-contrast T1 relaxation times for liver ECV fraction determination might be obtained at only one time point.

中文翻译：

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肝纤维化的定量：在大鼠动物模型中使用仅MRI推注技术的细胞外体积分数。

背景

若要确定在不同时间点进行单次浓注肝细胞外体积（ECV）分数测量的实用性，以检测和量化肝纤维化。

方法

四氯化碳（CCl ₄）中毒在23只雄性Sprague-Dawley大鼠中诱发了不同等级的肝纤维化。在十只对照大鼠中，未诱导出纤维化。通过使用定量磁共振成像（MRI）映射评估原始T1值和ECV分数；仅应用了一个造影剂（加多布特罗0.1 mmol / kg）。注射后5、15和25分钟确定ECV值。通过天狼星红染色在组织学上定量肝纤维化。

结果

对于为期8周的CCl ₄组，注射后获得的ECV分数值分别为5（23.5±4.8％，均值±标准偏差），15（23.6±4.8％）和25分钟（23.7±4.7％）。时间（p  = 0.998）；16周CCl ₄组和对照组在注射后5–25分钟也观察到恒定数据。15分钟后的肝ECV随着纤维化的严重程度显着增加：18.0±3.0％（对照组）对23.6±4.8％（8周CCl4）对30.5±3.3％（16周CCl4）（p  <0.001）。5、15和25分钟后的ECV值与Sirius红染色显着相关（ 对于所有参数，p <0.001）。

结论

可以在注射后5、15和25分钟测量使用单对比推注技术获得的肝ECV，获得随时间变化的恒定值，每个值都适合检测弥漫性肝纤维化。在临床实践中，可能仅在一个时间点获得用于肝ECV分数测定的对比后T1弛豫时间。