Application of Benchtop-magnetic resonance imaging in a nude mouse tumor model

We used a prototype of an in vivo BT-MRI apparatus to visualise organs and tumors and to analyse tumor progression in nude mouse xenograft models of human testicular germ cell tumor and colon carcinoma.Subcutaneous xenografts were easily identified as relative hypointense areas in transaxial slices of NMR images. Monitoring of tumor progression evaluated by pixel extension analyses based on NMR images correlated with increasing tumor volume calculated by calliper measurement. Gd-BOPTA contrast agent injection resulted in a better differentiation between parts of the urinary tissues and organs due to fast elimination of the agent via kidneys. In addition, interior structuring of tumors could be observed. A strong contrast enhancement within a tumor was associated with a central necrotic/fibrotic area.BT-MRI provides satisfactory image quality to visualize organs and tumors and to monitor tumor progression and structure in mouse models.MRI plays a key role in the preclinical development of new drugs, diagnostics and their delivery systems. However, very high installation and running cost of existing superconducting MRI machines limit the spread of the method. The new method of Benchtop-MRI (BT-MRI) has the potential to overcome this limitation due to much lower installation and almost no running costs. The lower quality of the NMR images is expected due to the low field strength and decreased magnet homogeneity. However, very recently we could show that BT-MRI is able to characterize floating mono- or bilayer tablets, osmotic controlled push-pull tablets [1-4] or scaffolds for tissue engineering in vitro [5]. A broad, important and increasing range of MRI applications are linked with preclinical studies on small rodents such as mice or rats [6-8]. Thereby, first developments and testing of more compact MRI systems have been reported [9,10]. In the present study we have tested a prototype of a new in vivo BT-MRI apparatus.Clearly, BT-MRI could overcome one of the curre