title: The utility of micro-CT and MRI in the assessment of longitudinal growth of liver metastases in a preclinical model of colon carcinoma.
abstract: OBJECTIVE
  Liver is a common site for distal metastases in colon and rectal cancer. Numerous clinical studies have analyzed the relative merits of different imaging modalities for detection of liver metastases. Several exciting new therapies are being investigated in preclinical models. But, technical challenges in preclinical imaging make it difficult to translate conclusions from clinical studies to the preclinical environment. This study addresses the technical challenges of preclinical magnetic resonance imaging (MRI) and micro-computed tomography (CT) to enable comparison of state-of-the-art methods for following metastatic liver disease.
  
  
  METHODS
  We optimized two promising preclinical protocols to enable a parallel longitudinal study tracking metastatic human colon carcinoma growth in a mouse model: T2-weighted MRI using two-shot PROPELLER (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction) and contrast-enhanced micro-CT using a liposomal contrast agent. Both methods were tailored for high throughput with attention to animal support and anesthesia to limit biological stress.
  
  
  CONCLUSIONS
  Each modality has its strengths. Micro-CT permitted more rapid acquisition (<10 minutes) with the highest spatial resolution (88-micron isotropic resolution). But detection of metastatic lesions requires the use of a blood pool contrast agent, which could introduce a confound in the evaluation of new therapies. MRI was slower (30 minutes) and had lower anisotropic spatial resolution. But MRI eliminates the need for a contrast agent and the contrast-to-noise between tumor and normal parenchyma was higher, making earlier detection of small lesions possible. Both methods supported a relatively high-throughput, longitudinal study of the development of metastatic lesions.
authors.affiliation: Center for In Vivo Microscopy, Department of Radiology, Box 3302, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Prachi
authors.initials: P
authors.lastname: Pandit
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Johnston
authors.forename: Yi
authors.initials: Y
authors.lastname: Qi
authors.forename: Jennifer
authors.initials: J
authors.lastname: Story
authors.forename: Rendon
authors.initials: R
authors.lastname: Nelson
authors.forename: G Allan
authors.initials: GA
authors.lastname: Johnson
mesh_terms: D000818:Animals; D003110:Colonic Neoplasms / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D007091:Image Processing, Computer-Assisted; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000556:secondary*; D008279:Magnetic Resonance Imaging; D051379:Mice; D008819:Mice, Nude; D008852:Microradiography; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media