Department of Radiology, Seoul National University College of Medicine, Seoul 03080, Korea.
Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul 03080, Korea.
Korean J Radiol. 2018 Jan-Feb;19(1):153-157. doi: 10.3348/kjr.2018.19.1.153. Epub 2018 Jan 2.
OBJECTIVE: To preliminarily evaluate technical feasibility of a dual-echo ultrashort echo time (UTE) subtraction MR imaging by using concurrent dephasing and excitation (CODE) sequence for visualization of iron-oxide enhancement in focal inflammatory pulmonary lesions. MATERIALS AND METHODS: A UTE pulmonary MR imaging before and after the injection of clinically usable superparamagnetic iron-oxide nanoparticles, ferumoxytol, was conducted using CODE sequence with dual echo times of 0.14 ms for the first echo and 4.15 ms for the second echo on 3T scanner in two rabbits concurrently having granulomatous lung disease and lung cancer in separate lobes. A mean ratio of standardized signal intensity (SI) was calculated for comparison of granulomatous lesion and cancer at first echo, second echo, and subtracted images. Lesions were pathologically evaluated with Prussian blue and immunohistochemistry staining. RESULTS: Post-contrast subtracted CODE images visualized exclusive enhancement of iron oxide in granulomatous disease, but not in the cancer (mean ratio of SI, 2.15 ± 0.68 for granulomatous lesion versus 1.00 ± 0.07 for cancer; value = 0.002). Prussian blue and corresponding anti-rabbit macrophage IgG-staining suggested an intracellular uptake of iron-oxide nanoparticles in macrophages of granulomatous lesions. CONCLUSION: Dual-echo UTE subtraction MR imaging using CODE sequence depicts an exclusive positive enhancement of iron-oxide nanoparticle in rabbits in focal granulomatous inflammatory lesions.
目的:初步评估使用双回波超短回波时间(UTE)减影磁共振成像技术(通过使用并发失相和激发(CODE)序列)对局灶性炎性肺病变中铁氧化物增强的可视化的技术可行性。
材料与方法:在两只兔子中,一只兔子同时患有肺部肉芽肿病和肺癌,另一只兔子则患有肺部肉芽肿病,在 3T 扫描仪上使用 CODE 序列对肺部进行 UTE 磁共振成像,序列的双回波时间分别为第一回波的 0.14ms 和第二回波的 4.15ms,在注射临床可用的超顺磁性氧化铁纳米颗粒(ferumoxytol)前后进行。计算第一回波、第二回波和减影图像中标准化信号强度(SI)的平均比值,用于比较肉芽肿病变和癌症。通过普鲁士蓝和免疫组织化学染色对病变进行病理评估。
结果:对比增强后 CODE 减影图像显示,铁氧化物仅增强了肉芽肿性病变,而未增强癌症(SI 的平均比值,肉芽肿病变为 2.15±0.68,癌症为 1.00±0.07; 值=0.002)。普鲁士蓝和相应的抗兔巨噬细胞 IgG 染色表明,铁氧化物纳米颗粒被巨噬细胞内吞到了肉芽肿病变中。
结论:使用 CODE 序列的双回波 UTE 减影磁共振成像可以在兔子的局灶性肉芽肿性炎症病变中描绘出铁氧化物纳米颗粒的特异性阳性增强。
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