Hedgire Sandeep, Krebill Cicely, Wojtkiewicz Gregory R, Oliveira Irai, Ghoshhajra Brian B, Hoffmann Udo, Harisinghani Mukesh G
1 Department of Radiology, Division of Cardiovascular Imaging Massachusetts General Hospital , Boston, MA , USA.
2 Department of Biology, Northeastern University , Boston, MA , USA.
Br J Radiol. 2018 Dec;91(1092):20180461. doi: 10.1259/bjr.20180461. Epub 2018 Sep 12.
: Radiation therapy for cancer can lead to atherosclerosis by inducing inflammatory changes in the vascular wall. It is difficult to quantitatively measure inflammation on CT and MRI studies. The purpose of this study was to assess the use of ferumoxytol, an ultrasmall superparamagnetic iron oxide nanoparticle, as a noninvasive marker of vessel wall inflammation secondary to radiation therapy in pancreatic cancer patients in comparison with healthy volunteers.
: MRI of upper abdomen (T, T, multi echo T* weighted imaging) was performed on 3 T magnet before and 48 h after intravenous administration of ferumoxytol in pancreatic cancer patients who underwent radiation therapy (n = 8) and in healthy volunteers (n = 8). R* value was obtained by drawing regions of interest outlining the aortic wall directly on the T* medic image and subsequently transposed to the R* image using Amira software (v. 5.3.2, FEI, Bordeaux, France). The change in R* values was analyzed by student's t-test.
: The average change in R* value of the pancreatic cancer patients was determined to be 216.1 ms. The average change R* value of the control patients was determined to be 54.6 ms. Thus, pancreatic cancer patients following radiation therapy had a greater uptake of ferumoxytol (p = 0.0082) in their aortic wall as compared to healthy controls.
: This proof of concept study suggests that greater uptake of ferumoxytol in the aortic wall in cancer patients without visible atherosclerosis may be the expression of increased inflammation.
: Ultrasmall superparamagnetic iron oxide enhanced MRI can offer an imaging biomarker for quantitative estimation of aortic inflammation preceding atherosclerosis.
癌症放射治疗可通过诱导血管壁炎症变化导致动脉粥样硬化。在CT和MRI研究中难以定量测量炎症。本研究的目的是评估与健康志愿者相比，使用超小超顺磁性氧化铁纳米颗粒（ferumoxytol）作为胰腺癌患者放射治疗继发血管壁炎症的非侵入性标志物。
对接受放射治疗的胰腺癌患者（n = 8）和健康志愿者（n = 8）在静脉注射ferumoxytol前及注射后48小时在3T磁体上进行上腹部MRI（T1、T2、多回波T2加权成像）。通过直接在T2医学图像上绘制勾勒主动脉壁的感兴趣区域，然后使用Amira软件（v. 5.3.2，FEI，法国波尔多）将其转换为R2图像，获得R2值。采用学生t检验分析R2*值的变化。
胰腺癌患者的R2值平均变化为216.1ms。对照患者的R2值平均变化为54.6ms。因此，与健康对照相比，接受放射治疗的胰腺癌患者主动脉壁对ferumoxytol摄取更多（p = 0.0082）。
这项概念验证研究表明，在无可见动脉粥样硬化的癌症患者中，主动脉壁对ferumoxytol摄取增加可能是炎症增加的表现。
超小超顺磁性氧化铁增强MRI可为动脉粥样硬化前主动脉炎症的定量评估提供一种成像生物标志物。
