Table 2.
Scanners and the scanning protocols used for healthy and nonsevere asthmatic and severe asthmatic subjects in different institutions
| Imaging Center | Center 1 | Center 2 | Center 3 | Center 4 |
|---|---|---|---|---|
| Scanner model | Siemens Sensation 64 slice | GE VCT 64 slice | Siemens Sensation 16 Slice | GE |
| Scan type | Spiral | Helical | Spiral | Helical |
| Rotation time, s | 0.5 | 0.5 | 0.5 | 0.5 |
| Detector configuration channel no. × mm | 64 × 0.6 mm | 64 × 0.625 mm | 16 × 0.75 mm | 16 × 1.25 mm |
| Pitch | 1.0 | 0.984 | 1.5 | 1.675 |
| Peak kilovoltage, kVp | 120 | 120 | 120 | 120 |
| Siemens = effective mAs* | Effective | mA | Effective | mA 50 |
| GE = mAs* | mAs 100 | S-145; M-180; L-270 | mAs 33 | |
| Dose modulation | Care dose OFF | Auto mA OFF | Care dose OFF | Smart mA off |
| Reconstruction algorithm | B35 | Standard or detail | B30 | Standard or detail |
| Lung algorithm | None | None | None | None |
| Additional image filters | No selection | No selection | No selection | No selection |
| Thickness, mm | 0.75 | 0.625 | 1.0 | 1.25 |
| Interval, mm | 0.5 | 0.5–0.625 | 0.5–1.0 | 0.625 |
| Iterative reconstruction (noise reduction algorithm) | No selection | No selection | No selection | No selection |
| Scan Time (30-cm length), s | <10 | <10 | <15 | <20 |
GE, General Electric; mAs, millampere second.
*
mA was varied for center 2 protocol based on BMI size [small (S): BMI <20; medium (M): 20 ≤ BMI ≤30, large (L): BMI >30].