Table 2.
Effect of clinical rules on iRENEX detecting obstruction
| Rule | Inferred evidence of obstruction | CF | Frequency of usea |
|---|---|---|---|
| Hydronephrosis | Very mild positive evidence | 0.1 | 39 |
| Hydronephrosis and abnormal function | Very mild positive evidence | 0.1 | 27 |
| Hydronephrosis and hydroureter | Very mild positive evidence | 0.1 | 12 |
| Ureteral stent | Mild negative evidence | –0.2 | 10 |
| Hydroureter and abnormal function | Very mild positive evidence | 0.1 | 8 |
| Renal calculus | Mild positive evidence | 0.2 | 6 |
| Ureteral calculus | Mild positive evidence | 0.2 | 5 |
| Flank pain on arrival | Very mild positive evidence | 0.1 | 5 |
| Ureteral stricture | Moderate positive evidence | 0.3 | 2 |
| Nephrostomy | Mild negative evidence | –0.2 | 2 |
| Pyeloplasty | Moderate negative evidence | –0.3 | 2 |
| Negative hydronephrosis | Mild negative evidence | –0.2 | 2 |
a
Frequency of use means how many times a rule was used in processing all the patients. Using a rule means that the IF part of the rule was found to be true so the THEN part of the rule was executed which modified the certainty of the interpretation. For example, the Hydronephrosis row means that of the 100 kidneys, 39 where found to have hydronephrosis from the clinical information resulting in increasing the evidence of obstruction in each kidney by a certainty of 0.1 (very mild).