The volumetric relationship of white matter lesion and contrast-enhanced lesion in delayed radiation brain injury: an MRI-based study.

Purpose: This study investigated the volumetric relationship of white matter lesion (WML) and contrast-enhanced lesion (CEL) in delayed radiation brain injury (RBI) during the course of evolution.
Materials and Methods: MRI results in 45 patients with RBI after receiving radiation for nasopharyngeal carcinoma were analyzed. In total there were 75 lobes with RBI and 114 MRI examinations in this study. WML and CEL lesion volumes were measured. The lesion volume change of less than 5% or 0.25 cm(3) was regarded as being static.
Results: The average WML volume was 16.33 cm(3) (ranging 0.11 cm(3) to 102.83 cm(3)), and the average CEL volume was 3.15 cm(3) (ranging 0.03 cm(3) to 27.85 cm(3)). WML was larger than CEL in 164 measurements, and CEL was larger than WML in 10 measurements. In 64.3% follow-ups WML and CEL evolved in the same pattern; and in most follow-ups (93.8%) WML and CEL did not evolve in the opposite directions. A larger WML volume tended to have a larger CEL volume though this relationship was not linear.
Conclusion: Evolution of WML and CEL tended to follow the same pattern. WML tended to be larger than CEL, and larger WML tended to be associated with larger CEL.