Serial CT and MR imaging of carmustine wafers

Area of Science:

• Neuroradiology
• Neurosurgery
• Oncology

Background:

• Malignant glioma recurrence necessitates advanced treatment strategies.
• Biodegradable chemotherapy wafers offer a localized drug delivery option for recurrent gliomas.

Purpose of the Study:

• To characterize the CT and MR imaging appearance of chemotherapy-laden biodegradable wafers.
• To assess the imaging evolution of these wafers during the follow-up period post-implantation.

Main Methods:

• Retrospective analysis of CT and MR imaging studies from 21 patients with malignant glioma who received carmustine (BCNU) or placebo wafers.
• Evaluation of wafer attenuation on CT, signal abnormalities on MR, and changes in appearance over time up to 1 year.

Main Results:

• Acute wafers (<7 days) appeared linear and high-attenuation on CT, with decreased signal on T1 and T2 MR images.
• Wafers became less conspicuous after 2 months and did not enhance; BCNU presence did not alter imaging appearance.
• Transient edema and enhancement were observed in one postoperative tumor.

Conclusions:

• Chemotherapy wafers exhibit a characteristic imaging pattern: linear, high attenuation on early CT, and decreased signal on early MR.
• Wafers gradually decrease in conspicuity and do not enhance, with no discernible difference between BCNU-loaded and placebo wafers on imaging.
• Understanding this appearance is crucial for differentiating wafers from tumor recurrence or treatment effects in neuro-oncology imaging.