UC San Diego
Distinct effects of nuclear volume fraction and cell diameter on high b-value diffusion MRI contrast in tumors
- Author(s): White, NS
- Dale, AM
- et al.
Published Web Locationhttps://doi.org/10.1002/mrm.25039
© 2013 Wiley Periodicals, Inc. Purpose: While many recent studies have demonstrated improved detection and characterization of malignant lesions using high b-value diffusion imaging techniques, little is known about the underlying physical characteristics of tumor cells that modulate the restricted water signal at high b on clinical scanners.Methods: Monte Carlo simulations of diffusion in a synthetic tumor cell environment were used to study the specific effects of tumor cell diameter and nuclear volume fraction (m) on high b diffusion contrast.Results: Results indicate that clinical pulsed-gradient spinecho diffusion-weighted signals measured at high b (Δ4000 s/ mm2), long diffusion time (Δ ∼40-60 ms), and long echo time (TE ∼60-140 ms) are generally insensitive to tumor cell diameter, but increase exponentially with m. Moreover, these results are predicted by a simple analytic expression for the intracellular restricted water signal with elevated T2 for the intranuclear versus cytosolic compartment.Conclusion: Nuclear volume fraction is an important characteristic of cancer cells that modulates the apparent restriction of water at high b on clinical scanners. This model offers a possible explanation for the apparent unreliable correlation between tumor cell density (cellularity) and traditional ADC.
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