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

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 ϫ 1 mm ϫ 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 Ͻ 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 v e values of SSM were 116% to 176% larger than those of GKM. The median K trans and v e of two models were found significantly different (P Ͻ 0.01). The median 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.

Prediction of Response to Chemoradiation Therapy in Squamous Cell Carcinomas of the Head and Neck Using Dynamic Contrast-Enhanced MR Imaging

“…14,19 Regions of interest for metastatic nodal masses were drawn by a neuroradiologist (L.A.L.) on the basis of T1WI, T2WI, and T1WI-gadolinium images, which were used for measurement of tumor volume and the analysis of parametric maps.…”

“…12 More recently, pharmacokinetic models have been used to extract parameters related to tumor microcirculation by using DCE-MR imaging in head and neck cancers. 13,14 However, to our knowledge, there has been no report on the relationship between the pretreatment DCE-MR imagingϪ derived pharmacokinetic parameters of the metastatic node and treatment outcome in patients with head and neck cancer. The availability of such prognostic imaging markers could significantly contribute to the selection of the most effective treatment strategy for a given patient.…”

Prediction of Disease-Free Survival in Patients with Squamous Cell Carcinomas of the Head and Neck Using Dynamic Contrast-Enhanced MR Imaging

“…The DCE-MRI protocol used in this study was described previously. 10,15 Briefly, DCE-MRI was performed by using a fast 3D spoiled gradient-echo sequence, which was modified to acquire 8 angle-interleaved subaperture images from the full-echo radial data. seconds with fat and spatial saturations.…”

“…of Patients (N ϭ 66) Base of tongue 26 Tonsil 16 Larynx 9 Vallecula 2 Nasopharynx 2 Oropharynx 2 Hypopharynx 1 Unknown primary 8 TNM staging TxN2M0 10 TxN3M0 3 T0N2M0 1 T1N2M0 2 T2N1M0 1 T2N2M0 17 T2N3M0 2 T3N2M0 10 T4N1M0 2 T4N2M0 16 T4N3M0 2 rithms described previously. 15,17 Regions of interest were drawn on the solid-appearing portion of the nodal mass by a trained neuroradiologist by using T2-weighted, T1-weighted, or postcontrast T1-weighted images, avoiding necrotic/cystic or hemorrhagic parts as well as surrounding blood vessels on all imaging sections encompassing the node. Pharmacokinetic analysis of the DCE-MRI data was performed for each voxel in the selected region of interest by using the shutter-speed model reported earlier.…”

“…Pharmacokinetic analysis of the DCE-MRI data was performed for each voxel in the selected region of interest by using the shutter-speed model reported earlier. 10,15 These regions of interest were also used for the volumetric analysis. Median pretreatment K trans values were computed from the larg- …”