Longitudinal three-dimensional-T2WI-SPACE study on wallerian degeneration in cat corticospinal tract and underlying pathology changes.

PURPOSE

To investigate the feasibility of T2W-SPACE technique in early detection of WD, the signal evolutions of degenerated corticospinal tract (CST) on T2W-SPACE, and their underlying pathological changes.

MATERIALS AND METHODS

The WD model of the CST was established in 23 cats through excision of cortical origins of the tract. Eight cats were scanned with the T2W-SPACE technique at 8 sequential time points, i.e. 0 (before modeling), 2, 4, 6, 8, 10, 20 and 30 days after modeling, and then they were pathologically examined. The remaining 15 cats (3 per group) also underwent pathological examination at 2, 4, 6, 10 and 20 days after modeling, respectively. The ratios of T2 signal intensity (rT2s) between the affected and unaffected sides of CST were analyzed.

RESULTS

During the first 4 days, SPACE could not detect any significant changes of the affected CST, although axonal degeneration was pathologically observed at the second day. From 6 to 10 days, the rT2s decreased monotonously, which is corresponded to histological findings of myelin degeneration and phagocyte proliferation. From 10 to 20 days, rT2s kept relatively stable at a low level and started to recover after that; the pathological changes of this period was characterized by marked phagocytizing activities.

CONCLUSION

SPACE technique can detect Wallerian degeneration at an early stage, and the signal evolution is consistent with the pathological processes.