Distinct effects of nuclear volume fraction and cell diameter on high b‐value diffusion MRI contrast in tumors. Issue 5 (19th December 2013)

• Record Type: Journal Article
• Authors: White, Nathan S.; Dale, Anders M.
• Is Part Of: Magnetic resonance in medicine. Volume 72:Issue 5(2014:Nov.)
• Page Start: 1435
• Page End: 1443
• Publication Date: 2013-12-19
• Subjects: Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.25039
• Languages: English
• ISSNs: 0740-3194

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="mrm25039-sec-0001" sec-type="section"> <title>Purpose</title> <p>While many recent studies have demonstrated improved detection and characterization of malignant lesions using high <italic>b</italic>‐value diffusion imaging techniques, little is known about the underlying physical characteristics of tumor cells that modulate the restricted water signal at high <italic>b</italic> on clinical scanners.</p> </sec> <sec id="mrm25039-sec-0002" sec-type="section"> <title>Methods</title> <p>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 (<italic>ν</italic>) on high <italic>b</italic> diffusion contrast.</p> </sec> <sec id="mrm25039-sec-0003" sec-type="section"> <title>Results</title> <p>Results indicate that clinical pulsed‐gradient spin‐echo diffusion‐weighted signals measured at high <italic>b</italic> (∼4000 s/mm<sup>2</sup>), 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 <italic>ν</italic>. 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.</p> </sec> <sec id="mrm25039-sec-0004" sec-type="section"> <title>Conclusion</title> <p>Nuclear volume fraction is an important characteristic of cancer cells that modulates the apparent restriction of water at high <italic>b</italic> on clinical scanners. This model offers a possible explanation for the apparent unreliable correlation between tumor cell density (cellularity) and traditional ADC. Magn Reson Med 72:1435–1443, 2014. © 2013 Wiley Periodicals, Inc.</p> </sec> </abstract>