半乳糖基白蛋白-超顺磁性氧化铁在兔肝脏小肿瘤检出中的应用价值

The value of detection of small liver tumor with galactose-bovine-serum-albumin containing superparamagnetic iron oxide in rabbits

目的初步探讨半乳糖基白蛋白-超顺磁性氧化铁（Gal—BSA—SPIO）在肝脏小肿瘤检出中的应用价值。方法用半乳糖基白蛋白包被小粒径超顺磁性氧化铁（SPIO）制备Gal—BSA—SPIO，测定其粒径大小。建立兔VX2肝癌模型（肿瘤直径〈1．5cm），用数字表法随机分为Gal—BSA—SPIO和SPIO组，每组10只，每组再分为5和10μmol Fe／kg组，每组5只。所有实验动物均分别采用SE T2WI、快速自旋回波（FSE）T2WI和梯度回波（GRE）T2WI序列行MR平扫，并按实验分组行增强扫描，分别测量增强前后兔肝脏信噪比（SNR）和肿瘤与肝脏对比噪声比（CNR），并采用方差分析进行比较。扫描完毕后对肝脏及肿瘤组织进行病理检查。结果Gal—BSA—SPIO平均粒径为34．4nm，核心粒径为14．8nm。5μmol Fe／kgSPIO、5μmol Fe／kgGal—BSA—SPIO、10μmol Fe／kg SPIO和10μmol Fe／kg Gal—BSA—SPIO4组增强前后肝脏SNR差值SE序列分别为（1．92±0．42）、（3．75±0．51）、（3．25±0．72）、（4．73±0．34），FSE序列分别为（1.56±0．18）、（3．56±0.64）、（3．33±0．16）、（4．83±0．16），GRE序列分别为（5．55±0．91）、（9．58±0．66）、（9.20±0．29）、（10．63±0．32），不同对比剂及不同序列组间比较差异均有统计学意义（P值均〈0．01）。上述4组增强前后肿瘤与肝脏CNR差值SE序列分别为（2．22±0．68）、（5．27±0．22）、（4．25±0．51）、（6．97±0.63），FSE序列分别为（1．73±0．41）、（4．46±0．54）、（3．73±0．49）、（5．39±0．39），GRE序列分别为（5．98±0.71）、（11.79±0．57）、（9．57±0．54）、（14．64±1．35），不同对比剂及不同序列组间比较差异均有统计学意义（P值均〈0．01）。Gal—BSA—SPIO主要作用于肝实质细胞，而SPIO主要分布于Kupffer细胞内。结论Gal—BSA—SPIO具有良好的负向肝脏强化效应，对肝内小肿瘤的检出具有良好的潜在应用价值。

Objective To discuss the value of detection of small liver tumor with Galactose-Bovineserum-albumin containing superparamagetic （ Gal-BSA-SPIO ） in rabbits primarily. Methods Gal-BSA- SPIO was obtained by stabilizing small superparamagnetic iron with galactose-bovine-serum-albumin, and its size was measured. Models of liver tumor（ diameter 〈 1.5 cm ） in rabbits were founded. The animals were randomly divided into groups of SPIO （n = 10） and group of GaI-BSA-SPIO （n = 10）. Each group was further subdivided as 5 μmol Fe/kg group （ n = 5 ） and 10 μmol Fe/kg group （ n = 5 ） , respectively. All animals were performed magnetic resonance imaging before and after administration of agents according to groups. SE T2WI, FSE T2WI and GRE T2WI sequences were used. Then signal of noise（SNR） of liver and contrast-noise ratio（CNR） of tumor-liver were measured and compared statistically. The histopathology study was performed for liver and tumor specimens after MR imaging. Results The mean value for the volume size was 34.4 nm, and the core particle size was 14. 8 nm. The differences of liver SNR between before and after enhancement for 5 μmol Fe/kg SPIO, 5 μmol Fe/kg Gal-BSA-SPIO, 10 μmol Fe/kg SPIO and 10 μmol Fe/kg Gal-BSA-SPIO group were （1.92 ± 0.42）, （3.75 ± 0.51 ）, （3.25 ± 0. 72） and （4.73 ± 0. 34） on SE sequence, respectively ; （ 1.56 ± 0.18 ）, （ 3.56 ± 0. 64 ）, （ 3.33 ± 0. 16 ） and （ 4. 83 ± 0. 16 ） on PSE sequence, respectively ; （ 5.55 ± 0.91 ）, （9.58 ± 0. 66 ）, （ 9. 20 ± 0. 29 ） and （ 10.63 ± 0. 32 ） on GRE sequence, respectively. There were significant differences between all groups for different doses and agents and within all different sequences （ P 〈 0. 01 ）. The differences of tumor-liver CNR between before and after enhancement of these 4 groups were （ 2. 22 ± 0. 68 ）, （ 5.27 ± 0. 22 ）, （ 4. 25 ± 0. 51 ） and （ 6.97 ±0.63 ） on SE sequence, respectively ; （ 1.73 ± 0.41 ）, （4. 46 ± 0. 54）, （3.73 ± 0. 49） and （5.39 ± 0. 39 ） on FSE sequence, respectively ; （ 5. 98 ± 0.71 ）, （ 11.79 ± 0. 57 ）, （ 9. 57 ± 0. 54 ） and （ 14. 64 ± 1.35 ） on GRE sequence, respectively. The differences between all groups of different doses and agents and within all sequences showed significant （P 〈 0. 01 ）. Histopathological study revealed that Gal-BSA-SPIO was mainly distributed in hepatoeytes while SPIO mainly in Kupffer cells. Conclusion Gal-BSA-SPIO is a agent with good negative enhancement effect in liver. It may be helpful for detecting small tumor of liver.