The Combination of
IVIM
‐
DWI
and
BOLD
‐
fMRI
Ping‐Kang Chen, Li Ma, Zi‐Cong He, Li‐Ting Chen, Shang‐Ao Gong, Lei Zhang, Wei Cui, Nan Cui, Xue‐Zhi Wang ABSTRACT
Background
Photodynamic microenvironment‐modulating therapy (PMMT) represents a promising strategy for nasopharyngeal carcinoma (NPC). However, early assessment of therapeutic response remains challenging.
Purpose
To evaluate whether intravoxel incoherent motion diffusion‐weighted imaging (IVIM‐DWI) and blood oxygen level‐dependent functional MRI (BOLD‐fMRI) can noninvasively detect early responses to PMMT in an NPC xenograft model.
Study Type
Experimental, animal model.
Animal Model
Subcutaneous 5‐8F NPC xenograft model (110 female BALB/c nude mice).
Field Strength/Sequence
3.0 T, T2WI FSE sequence, IVIM‐DWI single‐shot echo‐planar imaging sequence, and BOLD‐fMRI SPGR sequence.
Assessment
Following tumor establishment, mice were randomly assigned to five treatment groups: PBS, NH 2 ‐MIL‐101(Fe), PPa@NH 2 ‐MIL‐101(Fe) + near‐infrared (P@MIL+NIR), Doxy@NH 2 ‐MIL‐101(Fe) (D@MIL), and PPa + Doxy@NH 2 ‐MIL‐101(Fe) + NIR (PD@MIL+NIR). IVIM‐DWI ( D and f ) and BOLD‐fMRI ( R 2 *) were acquired before and after treatment to assess changes in tumor microstructure, perfusion, and oxygenation. The proliferation, apoptosis, angiogenesis, and hypoxia of NPC tumor were evaluated by Ki‐67 immunofluorescence staining, TUNEL immunofluorescence staining, VEGF immunohistochemical staining, and HIF‐1α immunohistochemical staining.
Statistical Tests
One‐way ANOVA, the intraclass correlation coefficient (ICC), Pearson's correlation analysis, and the Least Significant Difference (LSD) test for post hoc pairwise comparisons, p value < 0.05 was considered significant.
Results
Good and excellent agreements between two evaluators can be seen (The range of ICCs was from 0.864 to 0.985). In P@MIL+NIR, D@MIL, and PD@MIL+NIR groups, D and f values initially decreased and then increased, while R 2 * values peaked at 0.5 h (63.20 ± 2.57, 61.62 ± 0.98, and 67.38 ± 1.37) and gradually declined. D , f , and R 2 * values were significantly correlated with the histological staining results.
Data Conclusion
The combination of IVIM‐DWI and BOLD‐fMRI could be used in monitoring the early therapeutic responses to PD@MIL‐based PMMT in NPC.
Evidence Level
1.
Technical Efficacy
Stage 1.