Magnetic Resonance Imaging Diagnosis of Metastatic Lymph Nodes in a Rabbit Model: Efficacy of PJY10, a New Ultrasmall Superparamagnetic Iron Oxide Agent, with Monodisperse Iron Oxide Core and Multiple-Interaction Ligands

Abstract

BackgroundAccurate diagnosis of lymph node metastasis is crucial in treatment planning for cancer patients. Despite the use of various parameters, making correct diagnosis of a small metastatic or a hyperplastic benign node is still a challenge. In this study, we evaluated the feasibility of detecting lymph node metastasis using a new ultrasmall superparamagnetic iron oxide particle, PJY10, in a rabbit model.MethodsTo make metastatic and benign lymph nodes, either VX2 carcinoma or fecal material suspension was inoculated into thighs of 56 rabbits three weeks or three days before magnetic resonance (MR) imaging, respectively. T2*-weighted 3T MR imaging was performed before and 24 hours after PJY10 injection (5.2 [n = 15], 7.8 [n = 17], and 10.4 [n = 24] mg Fe/kg). MR images were correlated with pathologic results to calculate sensitivity and specificity. Quantitative analysis of the signal intensity (SI) – number of voxels[low] (the fraction of the number of voxels with the normalized SI on the postcontrast image lower than that on the precontrast image) and mean SI ratio – was also performed for each lymph node.ResultsSensitivities were 100% at all three dosages, whereas specificity increased with increasing dosage (89% at 10.4 mg Fe/kg). The benign nodes had a significantly higher number of voxels[low] and a lower mean SI ratio than the metastatic nodes at the dosage of 10.4 mg Fe/kg (P<.001). Az values were 0.905 for the number of voxels[low] and 0.952 for the mean SI ratio. The number of voxels[low] (P = .019) and the mean SI ratio (P = .034) had significant correlations with the histopathologic area ratio of metastatic foci in the metastatic nodes at 10.4 mg Fe/kg.ConclusionsPJY10 enabled clear demonstration of lymph node metastasis with high sensitivity and specificity at its optimal dosage of 10.4 mg Fe/kg.

In-vivo Visualization of Iron Oxide Enhancement in Focal Pulmonary Inflammatory Lesions Using a Three-Dimensional Radial Gradient-Echo-Based Ultrashort Echo Time Sequence: A Preliminary Study

“…Round regions of interests were differently applied five times on consecutive baseline and post-contrast axial images within the margin of pulmonary lesions, not including vessel, airway, and adjacent normal parenchyma. For calculating signal-intensity (SI) ratio of those lesions ( 7 ), a mean SI ratio was calculated using the following formula: SI ratio = (SI lung lesion [ post USPIO] / SI muscle [ post USPIO]) / (SI lung lesion [ pre USPIO] / SI muscle [ pre USPIO]).…”

Functional roles of magnetic nanoparticles for the identification of metastatic lymph nodes in cancer patients

“…Instead, several novel USPIO-contained CAs, such as P904 [ 76 ] and PJY10 [ 77 ], and CS015 [ 78 ], have been well-developed to show better performance than ferumoxtran-10 in LNM MR lymphography in oncological fields. CS015, a polyacrylic acid (PAA) coated USPIO, enhances the long-term stability of USPIO in various solutions [ 79 ].…”

Optimization of micelle-encapsulated extremely small sized iron oxide nanoparticles as a T1 contrast imaging agent: biodistribution and safety profile

“…Consequently, ultrasmall superparamagnetic IONPs (USPIO) with a hydrodynamic size of 20–50 nm were introduced as a next-generation imaging agent, designed to evade reticuloendothelial system (RES) uptake and ensure longer blood circulation [ 10 ]. This advancement allowed for their application in a variety of clinical contexts, including lymph node [ 14 – 17 ], plaque [ 18 ], and central nervous system macrophage imaging [ 19 ]. Despite these developments, T2 contrast agents are not without their limitations, such as the ‘blooming effect’ [ 20 , 21 ], leading to the discontinuation of several iron oxide imaging agents in clinical settings across the United States and most of Europe [ 22 ].…”