MRI quantification of splenic iron concentration in mouse.
OBJECTIVE
To quantify hepatic and splenic iron load, which is a critical issue for iron overload disease diagnosis. MRI is useful to noninvasively determine liver iron concentration, but not proven to be adequate for robust evaluation of splenic iron load. We evaluated the usefulness of MRI-derived parameters to determine splenic iron concentration in mice.


METHODS
A mouse model of experimental iron load was used. Multi-echo spin-echo images of liver and spleen were acquired at 4.7 Tesla. The parameters were tested at all echoes with and without an external reference. Splenic and hepatic iron concentrations were determined using biochemical assay as the gold standard.


RESULTS
Our results show that (i) use of an internal or external reference is essential; (ii) optimal echo times were TE = 19.5 ms and TE = 32.5 ms for the liver and spleen, respectively; (iii) in the liver, the relationship between biochemical and MRI iron concentration determinations is logarithmic; (iv) in the spleen, the best relationship is an inverse function.


CONCLUSIONS
A single spin-echo sequence allows robust estimation of hepatic and splenic iron content. Parameters classically used for hepatic iron concentration cannot be applied to splenic iron determination, which requires both the specific sequence and the adapted fitting function.
Hitti
Eric
E
Université de Rennes 1, LTSI, Rennes, France. eric.hitti@univ-rennes1.fr
Eliat
Pierre-Antoine
PA
Abgueguen
Emmanuelle
E
Ropert
Martine
M
Leroyer
Patricia
P
Brissot
Pierre
P
Gandon
Yves
Y
Saint-Jalmes
Herve
H
Loréal
Olivier
O
D000818:Animals; D004195:Disease Models, Animal; D007501:Iron / Q000032:analysis / Q000378:metabolism*; D019190:Iron Overload / Q000175:diagnosis*; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism; D011897:Random Allocation; D012680:Sensitivity and Specificity; D013154:Spleen / Q000737:chemistry / Q000378:metabolism*; D018709:Statistics, Nonparametric
D007501:Iron