Comparison between magnetic resonance imaging and histological findings in the navicular bone of horses with foot pain.

The research investigates the correlation between the histological features of early navicular disease in horses and magnetic resonance imaging (MRI) findings. High-field MR images of 22 horses’ navicular bones were compared to histopathological findings to draw associations.

Methodology

• The study involved examining one or both front feet of 22 horses that had been experiencing foot pain for an approximate duration of 3 months.
• Diagnostic techniques used in the study included high-field Magnetic Resonance Imaging (MRI) and histopathology to glean detailed insights into the internal structure of the navicular bone.
• Various aspects of the navicular bone including the dorsal, palmar, proximal, and distal borders along with the spongiosa were assigned an MRI grade (ranging between 0-3) and a corresponding histological grade. These were then compared statistically.

Results

• Increased signal intensity in the spongiosa of the navicular bone was linked to a range of abnormalities including fat atrophy, loss of definition of cytoplasmic borders in lipocytes, burgeoning capillaries within the altered marrow fat, perivascular or interstitial edema, enlarged intertrabecular bone spaces, fibroplasia and the thinning of trabeculae showing loss of bone with varied shapes suggestive of a “moth-eaten” appearance.
• Significant relational patterns were observed among histological lesions of the fibrocartilage, calcified cartilage and subchondral bone.
• There were also significant correlations observed between MRI grading of the spongiosa and both the histological marrow fat grade and the maximum of the MRI grades for the fibrocartilage.

Conclusions

• Increased signal intensity in the spongiosa of the fat-suppressed MR images might appear in association with fibrocartilage lesions with or without subchondral bone. It may also indicate a separate disease entity, especially if it is diffused. The association reflects a plethora of alterations in the trabecular bone and marrow fat architecture.