Table 5. The SNR and CNR of GGNs under different tube current and reconstruction algorithm.
| mA | Reconstruction algorithm | CTnodule | SDnodule | CTair | SDair | SNR | CNR |
|---|---|---|---|---|---|---|---|
| 20 | DLIR-L | −724.79±105.42 | 56.88±7.45 | −1,002.45±5.41 | 32.95±1.99 | −12.75±0.99 | 8.44±3.21 |
| DLIR-M | −721.96±105.58 | 49.89±12.47 | −999.58±5.16 | 23.84±1.12 | −15.80±7.36 | 11.59±4.34 | |
| DLIR-H | −728.61±106.23 | 44.76±11.76 | −1,001.53±4.46 | 13.13±1.00 | −17.37±5.80 | 20.88±8.30 | |
| 30%ASIR-V | −737.62±133.42 | 116.17±34.54 | −96.72±5.73 | 77.27±3.52 | −7.36±4.63 | 2.91±1.77 | |
| 50%ASIR-V | −732.43±115.35 | 113.53±20.00 | −972.85±2.13 | 66.53±3.82 | −6.68±2.03 | 3.64±1.81 | |
| 80%ASIR-V | −723.63±116.92 | 78.17±24.10 | −982.56±4.61 | 51.19±5.35 | −9.92±2.75 | 5.14±2.49 | |
| FBP | −719.50±108.49 | 145.64±22.03 | −956.46±7.01 | 88.42±7.56 | −5.02±0.98 | 2.70±1.40 | |
| 30 | DLIR-L | −718.89±93.32 | 53.39±8.55 | −1,005.10±2.23 | 30.39±1.51 | −13.82±3.45 | 9.46±3.23 |
| DLIR-M | −714.88±97.62 | 48.24±11.09 | −104.46±2.35 | 21.24±0.81 | −15.75±5.20 | 13.61±4.46 | |
| DLIR-H | −724.79±100.79 | 44.52±14.00 | −1,003.82±2.87 | 12.14±0.13 | −18.37±8.80 | 23.01±8.28 | |
| 30%ASIR-V | −724.80±91.41 | 129.72±21.27 | −970.69±4.33 | 70.83±4.79 | −5.82±1.78 | 3.51±1.37 | |
| 50%ASIR-V | −722.09±82.07 | 114.13±12.37 | −976.07±3.44 | 61.70±4.44 | −6.24±1.26 | 4.12±1.46 | |
| 80%ASIR-V | −719.91±91.39 | 86.92±11.47 | −987.32±2.26 | 45.96±2.81 | −8.39±1.50 | 5.85±2.14 | |
| FBP | −723.72±99.66 | 168.11±32.85 | −961.45±3.02 | 82.92±7.05 | −4.54±1.65 | 2.85±1.12 | |
| 50 | DLIR-L | −724.02±101.23 | 40.57±7.36 | −1,005.46±1.66 | 25.56±1.61 | 18.44±4.71 | 11.16±4.39 |
| DLIR-M | −721.09±108.25 | 40.64±4.93 | −1,005.29±0.83 | 18.49±2.14 | 17.95±3.51 | 15.89±7.08 | |
| DLIR-H | −726±112.23 | 33.69±10.06 | −1,003±1.71 | 10.10±0.81 | 23.87±10.09 | 27.78±12.16 | |
| 30%ASIR-V | −728.68±103.02 | 121.63±25.73 | −973.42±3.71 | 68.33±4.36 | 6.32±1.99 | 3.62±1.61 | |
| 50%ASIR-V | −722.76±109.39 | 104.61±18.75 | −979.17±2.03 | 55.77±3.61 | 7.05±1.29 | 4.91±1.94 | |
| 80%ASIR-V | −721.60±103.41 | 71.56±24.17 | −989.08±2.64 | 41.79±5.38 | 10.78±2.98 | 6.45±2.56 | |
| FBP | −726.57±99.77 | 144.57±25.19 | −963.36±4.18 | 77.31±4.83 | 5.21±1.41 | 3.07±1.32 | |
| 70 | DLIR-L | −730.11±100.98 | 38.17±8.77 | −1,005.85±3.74 | 21.87±3.82 | 20.67±8.78 | 13.38±6.46 |
| DLIR-M | −731.87±109.73 | 33.34±8.23 | −1,004.62±2.17 | 15.63±1.85 | 24.07±11.06 | 17.92±8.24 | |
| DLIR-H | −730.68±107.73 | 32.17±9.51 | −1,004.79±1.53 | 8.79±0.86 | 25.66±12.94 | 31.94±14.91 | |
| 30%ASIR-V | −731.70±108.04 | 104.08±41.96 | −974.34±1.83 | 62.56±2.36 | 8.60±4.74 | 3.91±1.82 | |
| 50%ASIR-V | −733.39±112.72 | 95.79±18.29 | −981.79±0.93 | 52.69±3.07 | 8.10±2.84 | 4.76±2.27 | |
| 80%ASIR-V | −735.19±104.07 | 65.66±18.23 | −990.18±1.98 | 41.37±2.08 | 12.80±7.14 | 6.08±2.27 | |
| FBP | −730.26±107.73 | 140.83±23.96 | −966.67±3.24 | 75.27±5.65 | 5.42±1.78 | 3.19±1.59 | |
| 90 | DLIR-L | −738.99±107.52 | 34.85±7.64 | −1,005.48±2.16 | 20.39±1.51 | 22.36±7.75 | 13.14±5.45 |
| DLIR-M | −735.89±104.99 | 33.89±5.07 | −1,005.76±2.83 | 14.27±1.04 | 21.95±3.67 | 19.13±7.91 | |
| DLIR-H | −735.05±104.50 | 30.72±5.93 | −1,005.40±2.88 | 8.21±0.67 | 24.61±5.55 | 33.17±13.12 | |
| 30%ASIR-V | −741.62±105.48 | 103.52±12.21 | −976.09±3.31 | 60.45±8.07 | 7.18±0.77 | 3.89±1.67 | |
| 50%ASIR-V | −738.21±107.83 | 89.77±9.96 | −983.28±1.76 | 49.42±4.34 | 8.30±1.57 | 5.00±2.25 | |
| 80%ASIR-V | −766.27±146.75 | 56.96±13.50 | −952.80±65.95 | 39.40±4.28 | 14.77±7.52 | 5.07±4.94 | |
| FBP | −743.69±98.97 | 131.93±13.24 | −969.41±2.10 | 70.03±4.87 | 5.73±1.26 | 3.26±1.53 | |
| 100 | DLIR-L | −727.83±101.18 | 32.17±4.16 | −1,004.21±3.05 | 19.18±3.17 | 22.97±4.71 | 15.24±7.24 |
| DLIR-M | −730.04±108.11 | 31.36±2.98 | −1,004.68±2.59 | 14.37±1.44 | 23.52±4.52 | 19.63±8.83 | |
| DLIR-H | −724.19±100.42 | 30.50±3.14 | −1,003.78±2.56 | 8.02±1.04 | 24.11±5.28 | 35.98±15.34 | |
| 30%ASIR-V | −741.23±95.67 | 106.67±18.76 | −978.77±1.44 | 56.72±2.72 | 7.03±0.93 | 4.19±1.71 | |
| 50%ASIR-V | −732.90±97.58 | 85.84±9.49 | −983.88±2.24 | 50.58±3.54 | 8.58±1.18 | 5.01±2.06 | |
| 80%ASIR-V | −735.57±99.09 | 58.48±12.42 | −990.27±4.07 | 39.10±4.15 | 12.76±1.46 | 6.71±3.06 | |
| FBP | −736.57±111.72 | 121.52±19.44 | −971.49±2.58 | 69.21±5.35 | 6.23±1.68 | 3.40±1.63 | |
| 120 | DLIR-L | −737.77±105.54 | 28.34±4.64 | −1,006.37±3.23 | 17.54±1.42 | 26.41±4.69 | 15.68±6.94 |
| DLIR-M | −734.61±106.68 | 30.05±4.36 | −1,005.01±2.53 | 12.31±1.48 | 24.63±3.39 | 22.69±10.41 | |
| DLIR-H | −729.54±103.97 | 25.20±4.38 | −1,005.34±2.69 | 7.24±0.97 | 29.81±7.04 | 39.18±16.81 | |
| 30%ASIR-V | −734.40±99.50 | 91.12±15.56 | −981.59±2.49 | 55.41±4.92 | 8.34±2.35 | 4.56±2.04 | |
| 50%ASIR-V | −744.11±103.41 | 75.32±9.34 | −987.19±3.52 | 47.31±5.27 | 9.90±0.88 | 5.25±1.02 | |
| 80%ASIR-V | −741.07±109.36 | 51.68±12.47 | −998.79±1.95 | 36.84±3.06 | 14.69±2.29 | 7.01±3.33 | |
| FBP | −740.89±103.93 | 139.62±10.98 | −968.30±3.05 | 73.43±4.27 | 5.35±1.01 | 3.17±1.62 | |
| 150 | DLIR-L | −735.81±94.41 | 23.51±4.05 | −1,005.21±3.40 | 15.92±1.75 | 32.04±6.81 | 17.45±7.32 |
| DLIR-M | −734.44±93.17 | 24.63±4.24 | −1,004.50±3.51 | 11.10±1.12 | 30.41±5.96 | 24.91±9.91 | |
| DLIR-H | −732.24±103.23 | 23.32±7.47 | −1,004.07±2.64 | 6.65±0.96 | 34.72±13.66 | 42.79±20.26 | |
| 30%ASIR-V | −755.51±142.11 | 80.31±18.95 | −955.96±66.96 | 55.66±10.79 | 10.27±4.81 | 4.12±3.56 | |
| 50%ASIR-V | −738.56±103.15 | 76.32±16.44 | −986.44±3.65 | 46.86±4.96 | 10.10±2.98 | 5.51±2.81 | |
| 80%ASIR-V | −735.13±103.16 | 52.51±11.51 | −994.17±1.96 | 35.52±2.91 | 14.40±3.09 | 7.46±3.37 | |
| FBP | −745.57±91.79 | 102.95±17.85 | −975.67±2.21 | 62.48±4.22 | 7.41±1.49 | 3.75±1.67 |
GGNs, ground glass nodules; SD, standard deviation; SNR, signal-to-noise ratio; CNR, contrast-to-noise ratio; FBP, filtered back projection; ASIR-V, adaptive statistical iterative reconstruction; DLIR-L/M/H, deep learning image reconstruction-low/medium/high.