Diffusion-weighted magnetic resonance imaging of treatment-associated changes in recurrent and residual medulloblastoma: preliminary observations in three children.
OBJECTIVE
To emphasize a possible role of magnetic resonance (MR) diffusion-weighted imaging (DWI) for lesion conspicuity and detection of treatment effects in children with medulloblastoma.


METHODS
Three children with medulloblastoma (two residual and one recurrent) were examined repetitively by MR diffusion-weighted imaging. Regional assessment of the apparent diffusion coefficient (ADC) was done for tumorous lesions and periventricular white matter appearing normal on standard MR images.


RESULTS
All lesions were clearly visible on DWI. In the case of recurrent tumor, on one scan, DWI showed lesions that were not seen on contrast-enhanced MRI. Increase (41%) of ADC was seen in one lesion, which subsequently responded completely to treatment over 27 months' follow-up. Intermediate increases (23-26%) of ADC were found with partial therapy response in three lesions. In contrast, a decrease (-11%) of ADC in two lesions was seen with tumor progression.


CONCLUSIONS
These observations may suggest a role for DWI in early detection of metastatic disease and treatment monitoring of medulloblastoma, warranting a formal study.
Schubert
M I
MI
Max Planck Institute of Psychiatry, NMR Research Group, Munich, Germany. mirjam.schubert@nottingham.ac.uk
Wilke
M
M
Müller-Weihrich
S
S
Auer
D P
DP
D000293:Adolescent; D002528:Cerebellar Neoplasms / Q000473:pathology* / Q000628:therapy*; D002675:Child, Preschool; D003131:Combined Modality Therapy; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008527:Medulloblastoma / Q000473:pathology* / Q000628:therapy*; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D018365:Neoplasm, Residual / Q000175:diagnosis