TABLE 3.
Measurement variability and proposed treatment response thresholds.
| CV | MDD | |||
|---|---|---|---|---|
| Small cNF CV | Large cNF CV | Threshold to detect change in size of small cNF | Threshold to detect change in size of large cNF | |
| Vectra H1 | ||||
| Length | 3.8% | 3.4% | 10% | 10% |
| Width | 5.5% | 3.2% | 15% | 10% |
| Surface Area | 5.7% | 3.9% | 15% | 10% |
| Volume | 8.8% | 7.1% | 20% | 20% |
| LifeViz Micro | ||||
| Length | 3.2% | 3.2% | 10% | 10% |
| Width | 4.8% | 4.2% | 10% | 10% |
| Height | 8.0% | 6.3% | 20% | 15% |
| Surface Area | 4.8% | 3.5% | 10% | 10% |
| Volume | 11.0% | 6.6% | 25% | 15% |
| Cherry Imaging | ||||
| Length | 5.5% | 4.3% | 15% | 10% |
| Width | 4.3% | 3.9% | 10% | 10% |
| Height | 7.6% | 5.7% | 20% | 15% |
| Surface Area | 7.3% | 6.6% | 15% | 15% |
| Volume | 8.8% | 9.8% | 20% | 20% |
Note: Small cNFs were defined as ≤5 mm in diameter, large cNFs were defined as >5 mm in diameter. The MDD for each imaging system was defined as at least twice the CV. MDD were used to propose treatment response thresholds to detect a change in cNF size in future clinical studies. The following colours represent thresholds for MDD: orange = 21%–25%; yellow = 16%–20%; blue = 11%–15% and green = ≤ 11%.
Abbreviations: cNF, cutaneous neurofibroma; CV, coefficient of variation; MDD, minimal detectable difference.