Diffusion tensor and tensor metrics imaging in intracranial epidermoid cysts.

Area of Science:

• Neuroimaging
• Radiology
• Biophysics

Background:

• Diffusion Tensor Imaging (DTI) provides insights into tissue microstructure.
• Diffusion Tensor Metrics (DTM) quantify diffusion anisotropy, offering more detailed structural information than Fractional Anisotropy (FA).
• Epidermoid cysts are tumors whose structural pathology can be challenging to characterize non-invasively.

Purpose of the Study:

• To evaluate the effectiveness of DTI and DTM in characterizing the structural pathology of epidermoid cysts.
• To correlate DTI findings with histopathological features of epidermoid cysts.

Main Methods:

• DTI was performed on three patients diagnosed with epidermoid cysts.
• Key metrics including FA, mean diffusivity (Dav), and DTM (CL, CP, CS) were measured.
• Measurements were taken from the tumor core and compared with normal-appearing white matter, followed by histopathological correlation.

Main Results:

• Epidermoid cysts exhibited high FA values, comparable to normal white matter, but lower than white matter tracts.
• Diffusion restriction was not observed on exponential apparent diffusion coefficient (eADC) maps.
• Elevated planar anisotropy (CP) and reduced linear anisotropy (CL) were noted in epidermoid cysts compared to white matter.

Conclusions:

• High CP values indicate a 2D diffusion pattern, likely due to the organized keratin structures within epidermoid cysts.
• DTI and DTM are valuable advanced imaging techniques for assessing the microstructural anatomy of epidermoid cysts.
• Histopathology confirmed the presence of well-structured keratin filaments and flakes, supporting the DTI findings.