Table 4. Diagnostic image quality and confidence level scored by the senior (radiologist 1) and junior (radiologist 2) radiologists on ULD and STD dose chest CT images.
| Subjective image quality parameters | STD | ULD | R1 vs. R2 | STD vs. ULD | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Kappa: inter-observer | P value: inter-protocol | |||||||||
| R1 | R2 | R1 | R2 | SD | ULD | R1 | R2 | |||
| Diagnostic image quality | 0.86 (0.76; 0.96) | 0.87 (0.78; 0.96)] | P<0.001 | P<0.001 | ||||||
| Excellent | 354 | 360 | 270 | 247 | ||||||
| Good | 26 | 20 | 97 | 113 | ||||||
| Acceptable | 0 | 0 | 13 | 19 | ||||||
| Suboptimal | 0 | 0 | 0 | 1 | ||||||
| Unacceptable | 0 | 0 | 0 | 0 | ||||||
| Confidence level | 0.40 (0.31; 0.48) | 0.18 (0.13; 0.24) | 0.42 | P<0.001 | ||||||
| Certain | 378 | 372 | 376 | 344 | ||||||
| Uncertain | 2 | 8 | 4 | 36 | ||||||
Outcomes of inter observer agreement between readers for both chest CT protocols and inter-protocol comparison for each reader are depicted. A P value lower than 0.05 was considered significant. R1, radiologist 1; R2, radiologist 2; ULD, ultra-low-dose; STD, standard; CT, computed tomography.