Noninvasive monitoring of a murine model of metastatic pheochromocytoma: a comparison of contrast-enhanced microCT and nonenhanced MRI.
OBJECTIVE
To compare contrast-enhanced micro-computed tomography (microCT) and nonenhanced respiratory-triggered magnetic resonance imaging (MRI) in an animal model of metastatic pheochromocytoma. Animal models are becoming important in the study of cancer treatment and imaging is useful in minimizing the number of animals needed and reducing costs associated with autopsies. However, the choice of imaging modality is still evolving.


METHODS
Adult female nude mice were injected by tail vein with a mouse pheochromocytoma (MPC) cell line (MPC 4/30PRR) to create a metastatic model. After optimizing imaging techniques, eight mice were imaged with both respiratory triggered MRI and microCT and the findings were verified histologically.


RESULTS
MicroCT and MRI were approximately equal in their ability to detect hepatic metastases at a size threshold of 350 microm. In the lungs, MRI was more sensitive than microCT, detecting lesions 0.6 mm in diameter versus 1 mm for microCT. Additionally, MRI was more sensitive for lesions in the kidneys, bone, ovaries, and adrenal glands. MRI demonstrated a higher contrast-to-noise ratio (CNR) than microCT.


CONCLUSIONS
In addition to the advantage of not exposing the animal to ionizing radiation, MRI provided a more complete assessment of the extent of metastases in this model compared to microCT.
Martiniova
Lucia
L
Reproductive and Adult Endocrinology Program, National Institutes of Child Health and Human Development, Bethesda, Maryland 20892-1109, USA.
Kotys
Melanie S
MS
Thomasson
David
D
Schimel
Daniel
D
Lai
Edwin W
EW
Bernardo
Marcelino
M
Merino
Maria J
MJ
Powers
James F
JF
Ruzicka
Jan
J
Kvetnansky
Richard
R
Choyke
Peter L
PL
Pacak
Karel
K
D000310:Adrenal Gland Neoplasms / Q000175:diagnosis* / Q000473:pathology; D000818:Animals; D001859:Bone Neoplasms / Q000175:diagnosis / Q000556:secondary; D003287:Contrast Media; D004195:Disease Models, Animal; D005260:Female; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007680:Kidney Neoplasms / Q000175:diagnosis / Q000556:secondary; D008114:Liver Neoplasms, Experimental / Q000175:diagnosis* / Q000556:secondary; D008175:Lung Neoplasms / Q000175:diagnosis / Q000556:secondary; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008819:Mice, Nude; D008991:Monitoring, Physiologic / Q000379:methods*; D010673:Pheochromocytoma / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary; D012680:Sensitivity and Specificity; D055114:X-Ray Microtomography / Q000379:methods*
D003287:Contrast Media