# Evaluation of the effect of transcytolemmal water exchange analysis for therapeutic response assessment using DCE-MRI: a comparison study.

Journal Article (Journal Article)

This study compares the shutter-speed (SS) and the Tofts models as used in assessing therapeutic response in a longitudinal DCE-MRI experiment. Sixteen nu/nu mice with implanted colorectal adenocarcinoma cell line (LS-174T) were randomly assigned into treatment/control groups (n = 8/group) and received bevacizumab/saline twice weekly (Day1/Day4/Day8). All mice were scanned at one pre- (Day0) and two post-treatment (Day2/Day9) time points using a high spatiotemporal resolution DCE-MRI pulse sequence. The CA extravasation rate constant [Formula: see text] from the Tofts/SS model and the mean intracellular water residence time [Formula: see text] from the SS model were analyzed. A biological subvolume (BV) within the tumor was identified based on the [Formula: see text] intensity distribution, and the SS model parameters within the BV ([Formula: see text] and [Formula: see text]) were analyzed. It is found that [Formula: see text] and [Formula: see text] have a similar spatial distribution in the tumor volume. The Bayesian information criterion results show that the SS model was a better fit for all scans. At Day9, the treatment group had significantly higher tumor mean [Formula: see text] (p = 0.021), [Formula: see text] (p = 0.021) and [Formula: see text] (p = 0.045). When BV from transcytolemmal water exchange analysis was adopted, the treatment group had higher mean [Formula: see text] at both Day2 (p = 0.038) and Day9 (p = 0.007). Additionally, at Day9, the treatment group had higher mean [Formula: see text] (p = 0.045) and higher [Formula: see text] spatial heterogeneity indices (Rényi dimensions) d 1 (p = 0.010) and d 2 (p = 0.021). When mean [Formula: see text] and its coefficient of variation (CV) were used to separate treatment/control group samples using supporting vector machine, the accuracy of treatment/control classification was 68.8% at Day2 and 87.5% at Day9; in contrast, the Day2/Day9 accuracy were 62.5%/87.5% using tumor mean [Formula: see text] and its CV and were 50.0%/87.5% using tumor mean [Formula: see text] and its CV, respectively. These results suggest that the SS model parameters outperformed the Tofts model parameters in terms of capturing bevacizumab therapeutic effect in this longitudinal experiment.

### Full Text

### Duke Authors

### Cited Authors

- Wang, C; Subashi, E; Liang, X; Yin, F-F; Chang, Z

### Published Date

- July 7, 2016

### Published In

### Volume / Issue

- 61 / 13

### Start / End Page

- 4763 - 4780

### PubMed ID

- 27272391

### Pubmed Central ID

- PMC4929833

### Electronic International Standard Serial Number (EISSN)

- 1361-6560

### Digital Object Identifier (DOI)

- 10.1088/0031-9155/61/13/4763

### Language

- eng

### Conference Location

- England