Use of Nanoparticle Contrast Agents for Cell Tracking with Computed Tomography

Abstract

Efforts to develop novel cell-based therapies originated with the first bone marrow transplant on a leukemia patient in 1956. Preclinical and clinical examples of cell-based treatment strategies have shown promising results across many disciplines in medicine, with recent advances in immune cell therapies for cancer producing remarkable response rates, even in patients with multiple treatment failures. However, cell-based therapies suffer from inconsistent outcomes, motivating the search for tools that allow monitoring of cell delivery and behavior in vivo. Noninvasive cell imaging techniques, also known as cell tracking, have been developed to address this issue. These tools can allow real-time, quantitative, and long-term monitoring of transplanted cells in the recipient, providing insight on cell migration, distribution, viability, differentiation, and fate, all of which play crucial roles in treatment efficacy. Understanding these parameters allows the optimization of cell choice, delivery route, and dosage for therapy and advances cell-based therapy for specific clinical uses. To date, most cell tracking work has centered on imaging modalities such as MRI, radionuclide imaging, and optical imaging. However, X-ray computed tomography (CT) is an emerging method for cell tracking that has several strengths such as high spatial and temporal resolution, and excellent quantitative capabilities. The advantages of CT for cell tracking are enhanced by its wide availability and cost effectiveness, allowing CT to become one of the most popular clinical imaging modalities and a key asset in disease diagnosis. In this review, we will discuss recent advances in cell tracking methods using X-ray CT in various applications, in addition to predictions on how the field will progress.

CT Imaging of Enzymatic Activity in Cancer Using Covalent Probes Reveal a Size-Dependent Pattern

“… 12 Furthermore, inherent targeting of high-density lipoprotein particles 31 and cell labeling by GNPs were also successfully accomplished. 32 However, to the best of our knowledge there have been no reports on enzyme activity monitoring by the CT technique, most likely due to low sensitivity concerns. The goals of this work were to evaluate whether enzymatic activity can be detected by micro-CT, to assess the additional effect of protease targeting strategy compared to passive accumulation, and to select the optimal GNP size for visualization in vivo.…”

Comparison of Gold Nanoparticles and Iodinated Contrast Media in Radiation Dose Reduction and Contrast Enhancement in Computed Tomography

“…In 2012, Galper et al compared the contrast enhancement of gold nanoparticles with iodinated compounds. They revealed that the contrast enhancement of gold nanoparticles at 120 kVp is 1.9 times higher than that of iodinated compounds (17). Kim et al (10) assessed the contrast enhancement of gold nanoparticles with that of iodine contrast agent in the range of 1 to 3 M. Their results showed that gold nanoparticles provide 1.9 times better contrast.…”

Nanoparticle contrast agents for X‐ray imaging applications

“…Cell tracking with X-ray CT is a rapidly developing field (J. Kim, Chhour, et al, 2017). Astolfo et al (2013) provided the first evidence for in vivo cell tracking using AuNP combined with CT. Malignant cells were labeled with AuNP and F I G U R E 7 (a) DECT iodine and gold maps for hindlimb sarcomas in the groups treated with 5 Gy RT in conjunction with no AuNP (control), PEGylated AuNP (non-targeted), or RGD-functionalized AuNP (targeted).…”