Table 2.
Summary of imaging methods
| Time for Exam | Radiation Dose* | Spatial Resolution | Temporal Resolution | Imaging Measurements | |
|---|---|---|---|---|---|
| CT | |||||
| Inspiration/expiration | 5–10 min Total | 2–5 mSv for 2-whole lung scans | Up to 0.5 mm isotropic | Up to 0.3 s slice, <5 s whole lung | Specific volume change |
| Xe CT | approximately 10–20 min Total | High for washin/washout studies- depends on protocol and extent of lung imaged | Up to 0.5 mm isotropic | Up to 0.3 s slice, <5 s whole lung | Specific ventilation |
| Dual energy Xe CT | 5–10 min Total | High for washin/washout studies 1–5 mSv for single breath | Up to 0.5 mm isotropic | Up to 0.3 s slice, <5 s whole lung | Specific ventilation, inhaled gas distribution |
| 4DCT | 10–20 min Total | 30–40 mSv for low pitch helical study | Up to 0.5 mm isotropic | Up to 0.3 s slice, <5 s whole lung | Specific volume change |
| MRI | |||||
| Hyperpolarized Xe/He | approximately 5–10 min Total | None | 2D 3mmx10 mm 3D isotropic 3 mm voxels | 15 s acquisition 3D 40 cmx 40 cmx 30 cm every 20–30 s | Inhaled Gas distribution VDV, VDP, PVV |
| O2-enhanced 1H | approximately 30–60 min Total | None | 3 mm isotropic voxels | Specific ventilation | |
| UTE 1H static | approximately 5–10 min Total | None | 1 mm voxels | 3D 40 cmx 40 cmx 30 cm every 20–30 s | 1H Signal intensity |
| 4D (FD) 1H | approximately 20–30 min Total | none | 3 mm voxels | 90 s acquisition |
*
mSv, milliSievert WBDE (whole body dose equivalent). Compare with 3–10 mSv for standard dose chest helical CT, 1–2.5 mSv for low-dose helical chest CT, average background radiation exposure of 3–4 mSv/yr.