Table 4.
Number of successfully interpreted cases for each diagnostic task - at every dose-reconstruction configuration - using binary reader agreement rules. For positive cases, a majority of readers had to identify all lesions seen by a majority of readers using the routine dose level; for negative cases, the majority of readers made no non-lesion localizations (i.e., no false positive markings). Numbers in red indicate failure to meet preset thresholds for successful dose-reconstruction configurations. The number of cases with essential lesions reflects cases with target lesions identified by 2 or more readers at routine dose level.
| Contrast-enhanced abdominal CT for Hepatic Metastasis | |||||||
|---|---|---|---|---|---|---|---|
| Dose Level by AEC setting (QRM) | Reconstruction Kernel (FBP/IR) | # of readers with successful interpretation | Successful Interpretations All Cases |
Successful Interpretations Cases with (n=21): Cases without (n=23) essential Lesions |
|||
| 0/3 | 1/3 | 2/3 | 3/3 | ||||
| 200 | B30 | 0 | 3 | 9 | 32 | 41 | 20:21 |
| I30 | 0 | 3 | 9 | 32 | 41 | 19:22 | |
| 160 | B30 | 0 | 4 | 12 | 28 | 40 | 18:22 |
| I30 | 0 | 4 | 10 | 30 | 40 | 18:22 | |
| 120 | B30 | 2 | 4 | 5 | 33 | 38 | 16:22 |
| I30 | 1 | 4 | 8 | 31 | 39 | 18:21 | |
| 100 | B30 | 3 | 6 | 7 | 28 | 35 | 17:18 |
| I30 | 2 | 4 | 9 | 29 | 38 | 17:21 | |
| 80 | B30 | 3 | 6 | 10 | 25 | 35 | 14:21 |
| I30 | 4 | 4 | 8 | 28 | 36 | 14:22 | |
| 60 | B30 | 4 | 4 | 10 | 26 | 36 | 14:22 |
| I30 | 7 | 4 | 8 | 25 | 33 | 14:19 | |
| Unenhanced chest CT for Pulmonary Nodule detection | |||||||
| Dose Level by AEC setting (QRM)) | Reconstruction Kernel (FBP/IR) | # of readers with successful interpretation | Successful Interpretations All Cases |
Successful Interpretations Cases with (n=19): Cases without (n=25) essential Lesions |
|||
| 0/3 | 1/3 | 2/3 | 3/3 | ||||
| 70 | B50 | 1 | 3 | 12 | 28 | 40 | 19:21 |
| I50 | 1 | 1 | 10 | 32 | 42 | 19:23 | |
| 30 | B50 | 0 | 3 | 9 | 32 | 41 | 17:24 |
| I50 | 1 | 3 | 7 | 33 | 40 | 17:23 | |
| 10 | B50 | 0 | 4 | 8 | 32 | 40 | 18:22 |
| I50 | 1 | 2 | 5 | 36 | 41 | 17:24 | |
| 5 | B50 | 1 | 2 | 7 | 34 | 41 | 18:23 |
| I50 | 1 | 1 | 6 | 36 | 42 | 19:23 | |
| 2.5 | B50 | 2 | 6 | 4 | 32 | 36 | 13:23 |
| I50 | 2 | 3 | 8 | 31 | 39 | 16:23 | |
| Unenhanced spiral head CT to detect Intracranial Findings Causing Neurologic Deficit | |||||||
| Dose Level by effective mAs | Reconstruction Kernel (FBP/IR) | # of readers with successful interpretation | Successful Interpretations All Cases |
Successful Interpretations Cases with (n=18): Cases without (n=25) essential Lesions |
|||
| 0/3 | 1/3 | 2/3 | 3/3 | ||||
| 250 | H40(FBP) | 0 | 2 | 2 | 39 | 41 | 16:25 |
| J40 (IR) | 0 | 1 | 7 | 35 | 42 | 17:25 | |
| 200 | H40(FBP) | 0 | 2 | 4 | 37 | 41 | 17:24 |
| J40 (IR) | 0 | 2 | 7 | 34 | 41 | 17:24 | |
| 150 | H40(FBP) | 0 | 1 | 6 | 36 | 42 | 17:25 |
| J40 (IR) | 1 | 0 | 4 | 38 | 42 | 17:25 | |
| 100 | H40(FBP) | 0 | 0 | 10 | 33 | 43 | 18:25 |
| J40 (IR) | 0 | 2 | 6 | 35 | 41 | 16:25 | |
| 50 | H40(FBP) | 1 | 1 | 9 | 32 | 41 | 17:24 |
| J40 (IR) | 0 | 1 | 6 | 36 | 42 | 17:25 | |
| 25 | H40(FBP) | 2 | 3 | 8 | 30 | 38 | 14:24 |
| J40 (IR) | 2 | 0 | 11 | 30 | 41 | 16:25 | |
AEC = automatic exposure control setting, which adjusts the modulation of the CT system tube current; QRM = quality reference milliampere-seconds (mAs), the AEC setting that will produce the image quality at a similar effective mAs for a hypothetically normal-sized patient; FBP = filtered back projection; IR = iterative reconstruction