Abstract
In this study, we aimed to comparatively evaluate high-resolution 3D ultrasonography (hrUS), in-vivo micro-CT (μCT) and 9.4T MRI for the monitoring of tumor growth in an orthotopic renal cell carcinoma (RCC) xenograft model since there is a lack of validated, non-invasive imaging tools for this purpose. 1 × 106 Caki-2 RCC cells were implanted under the renal capsule of 16 immunodeficient mice. Local and systemic tumor growth were monitored by regular hrUS, μCT and MRI examinations. Cells engrafted in all mice and gave rise to exponentially growing, solid tumors. All imaging techniques allowed to detect orthotopic tumors and to precisely calculate their volumes. While tumors appeared homogenously radiolucent in μCT, hrUS and MRI allowed for a better visualization of intratumoral structures and surrounding soft tissue. Examination time was the shortest for hrUS, followed by μCT and MRI. Tumor volumes determined by hrUS, μCT and MRI showed a very good correlation with each other and with caliper measurements at autopsy. 10 animals developed pulmonary metastases being well detectable by μCT and MRI. In conclusion, each technique has specific strengths and weaknesses, so the one(s) best suitable for a specific experiment may be chosen individually.
Highlights
One important constraint inherent with the use of orthotopic renal cell carcinoma (RCC) xenografts hampers their widespread adoption, namely the difficulty to detect the tumors and to non-invasively monitor their growth
For μCT, we used a protocol providing a spatial resolution of 18 μm, because we considered this to be sufficient to precisely calculate tumor volumes and to visualize the renal tumor and the surrounding soft tissue
In this study we showed that high-resolution 3D ultrasonography, contrast-enhanced in-vivo micro-computed tomography (CT) and 9.4T small animal magnetic resonance imaging (MRI) are feasible tools for an accurate, non-invasive monitoring of tumor growth in orthotopic RCC xenograft models
Summary
One important constraint inherent with the use of orthotopic RCC xenografts hampers their widespread adoption, namely the difficulty to detect the tumors and to non-invasively monitor their growth. During the last years, imaging techniques commonly used in daily clinical practice for the diagnosis and follow-up of RCC patients have been transferred to the experimental preclinical setting by developing instruments and machines specially designed for the use in rodents and other small animals[10]. These techniques include – among others – ultrasonography (US)[11], computed tomography (CT)[12] and magnetic resonance imaging (MRI)[13]. We evaluated for the first time in direct comparison 3D high-resolution ultrasonography (hrUS), contrast-enhanced in-vivo micro-CT (μCT) and 9.4T MRI (MRI) to non-invasively monitor tumor growth in an orthotopic RCC xenograft model
Published Version (Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have