Representative coronal IDEAL water, fat, and fat fraction MR images show the
progression of steatosis in ob/ob mice compared with that
in a control ob/+ mouse. Corresponding slides
show increasing macro- and microvesicular steatosis accumulation
corresponding to imaging findings. (Hematoxylin-eosin stain
[H&E]; original magnification,
×100.) T2* correction and accurate spectral modeling
were used for these images. A marked increase in visceral and subcutaneous
fat and hepatic steatosis can be seen in the ob/ob mice
compared with the ob/+ mouse, and these features
are exaggerated in the 13-week-old ob/ob mouse compared
with the 7-week-old ob/ob mouse. Fat fraction images enable
quantification of fat and enable confirmation of visual suspicion of
steatosis: For instance, 0.0% ± 4.5, 14.4% ± 3.9, and
24.7% ± 6.6 fat was measured in the
ob/+ mouse, 7-week old ob/ob
mouse, and 13-week old ob/ob mouse, respectively.
Histologic grading revealed 0%, 50%, and 85% of cells were affected by
steatosis in the representative ob/+ mouse,
7-week old ob/obmouse, and 13-week old
ob/ob mouse, respectively.