Glioblastoma multiforme with atypical diffusion-weighted MR findings

Area of Science:

• Radiology
• Oncology
• Neuroscience

Background:

• Glioblastomas often present with complex cystic-necrotic components.
• Diffusion-weighted MRI (DW-MRI) is a key imaging technique for characterizing brain lesions.
• Understanding atypical features on DW-MRI is crucial for accurate diagnosis.

Purpose of the Study:

• To review DW-MRI findings in glioblastomas.
• To identify and analyze atypical features of glioblastomas on DW-MRI.
• To explore the reasons behind atypical DW-MRI characteristics.

Main Methods:

• Inclusion of 48 histologically confirmed glioblastoma cases.
• Performance of DW-MRI using spin-echo echo-planar sequence alongside conventional MRI.
• Classification of cystic-necrotic components as typical (low signal intensity) or atypical (high signal intensity) based on DW-MRI, with calculation of apparent diffusion coefficient (ADC) values.

Main Results:

• Six cases exhibited atypical high signal intensity in cystic components on DW-MRI.
• Typical lesions (low signal intensity) showed higher mean ADC values (2.36±0.46 x 10⁻³ mm²/s) compared to atypical lesions (1.06±0.17 x 10⁻³ mm²/s).
• The difference in ADC values between typical and atypical glioblastomas was statistically significant (p<0.001).

Conclusions:

• While most glioblastomas do not show restricted diffusion, some present with high signal intensity and reduced ADC values on DW-MRI.
• Atypical features on DW-MRI, including high signal intensity and decreased ADC values, are observed in a subset of glioblastomas.
• DW-MRI alone is insufficient to differentiate glioblastomas with low ADC values from abscesses presenting with similar conventional MRI findings.