Table 1.
Clinical experience with established and emerging MRI techniques for radiation therapy response assessment
| Imaging technique* | Tissue properties measured |
In-plane resolution (mm2) |
Slice thickness (mm) |
All published studies |
Published studies in assessing radiation treatment response |
|---|---|---|---|---|---|
| T1-W, T2-W MRI | Tumor delineation | 0.5-2 | 2-5 | +++++ | +++++ |
| DW MRI | Cellularity | 2-3 | 4-6 | ++++ | ++++ |
| DCE MRI | Permeability, perfusion | 2-3 | 4-6 | ++++ | ++++ |
| MR spectroscopy | Metabolite concentrations | 6-20 | 10-25 | ++ | ++ |
| BOLD MRI | Oxygenation | 2-4 | 3-6 | +++ | + |
| CEST MRI | Protein concentrations | 2-3 | 2-6 | +++ | +++ |
| Hyperpolarized 13C MRI | Pyruvate metabolism | 7-15 | 10-20 | + | + |
Abbreviations: BOLD = blood oxygenation level–dependent; CEST = chemical exchange saturation transfer; DCE = dynamic contrast-enhanced; DW = diffusion-weighted; T1 = T1-weighted; T2-W = T2-weighted.
+++++ = widespread clinical use. ++++ = published literature in a variety of tissue types; becoming widespread clinically. +++ = emerging technique with demonstrated clinical success in some tissues. ++ = older technique with limited success clinically. + = emerging technique with published experience limited to small animal imaging.
Parameters for standard T1-W MRI, T2-W MRI, DW MRI, DCE MRI, MR spectroscopy, BOLD MRI, and CEST MRI are summarized with input from an experienced clinical medical physicist (R. Jason Stafford, PhD). The listed spatial resolution and slice thickness for hyperpolarized MRI is as summarized in previous published clinical work in patients with prostate cancer (72).