Transcytolemmal water exchange in pharmacokinetic analysis of dynamic contrast-enhanced MRI data in squamous cell carcinoma of the head and neck.

Publication Type	Academic Article
Authors	Kim S, Quon H, Loevner L, Rosen M, Dougherty L, Kilger A, Glickson J, Poptani H
Journal	J Magn Reson Imaging
Volume	26
Issue	6
Pagination	1607-17
Date Published	12/01/2007
ISSN	1053-1807
Keywords	Body Water, Carcinoma, Squamous Cell, Contrast Media, Gadolinium DTPA, Head and Neck Neoplasms, Magnetic Resonance Imaging
Abstract	PURPOSE: To investigate the effect of transcytolemmal water exchange on the dynamic contrast-enhanced (DCE) T(1)-weighted MRI of human squamous cell carcinomas of the head and neck (HNSCC). MATERIALS AND METHODS: Nine patients with HNSCC nodal metastasis underwent pretreatment DCE-MRI with a temporal resolution of 2.5 seconds and a spatial resolution of 1 mm x 1 mm x 5 mm at 1.5T. We used two pharmacokinetic models for data analysis: generalized kinetic model (GKM) without considering transcytolemmal water exchange and the shutter-speed model (SSM), based on a two-site exchange model for transcytolemmal water exchange. The results were compared in three subgroups of voxels in the tumor depending on the level of contrast enhancement. RESULTS: SSM was found to be a better fit for more than 75% of pixels of all subjects (P < 0.01) in terms of residual size and Bayesian information criterion (BIC). For all three subgroups based on the contrast enhancement, the median K trans values of SSM were 42% to 55% higher than those of GKM and the median upsilon e values of SSM were 116% to 176% larger than those of GKM. The median K trans and upsilon e of two models were found significantly different (P < 0.01). The median tau i measured by SSM were from 211 to 364 msec. CONCLUSION: The effect of transcytolemmal water exchange is an important factor that needs to be incorporated for adequate modeling of contrast enhancement dynamics measured by MRI of HNSCC.
DOI	10.1002/jmri.21207
PubMed ID	17968962