Table 1.
Accuracy and precision of different semi-automated methods of measuring or estimating KV compared to manual segmentation
| Volume (ml) (mean ± SD) | % volume difference (mean ± SD) | Raw volume difference (mean ± SD) | ||
|---|---|---|---|---|
| Right KV | Manual (reference) | 563 ± 400 | – | – |
| Ellipsoid method* | 568 ± 394 | 4.5 ± 19.7 | 11.0 ± 129.4 | |
| Mid-slice method | 568 ± 405 | 1.9 ± 11.1 | 4.1 ± 72.6 | |
| Sheffield TKV Tool | 561 ± 392 | 0.5 ± 5.3 | − 2.8 ± 25.3 | |
| Left KV | Manual (reference) | 597 ± 417 | – | – |
| Ellipsoid method* | 576 ± 378 | 1.7 ± 17.6 | − 21.9 ± 162.9 | |
| Mid-slice method | 629 ± 452 | 6.1 ± 12.4 | 31.8 ± 79.0 | |
| Sheffield TKV Tool | 592 ± 419 | − 0.7 ± 5.5 | − 5.1 ± 29.7 | |
| TKV | Manual (reference) | 1167 ± 798 | – | – |
| Ellipsoid method* | 1238 ± 742 | 3.1 ± 14.1 | − 10.6 ± 223.76 | |
| Mid-slice method | 1196 ± 827 | 3.8 ± 9.2 | 35.9 ± 104.9 | |
| MIROS Tool | 1182 ± 821 | 1.4 ± 5.1 | 21.7 ± 60.8 | |
| Sheffield TKV Tool | 1153 ± 786 | − 0.3 ± 3.8 | − 7.9 ± 41.8 | |
Results are shown for all 61 patients (122 kidneys). Negative values indicate underestimation of KV compared to manual segmentation. Various methods were tested on images of kidneys with manual volumes (analyst A) as reference. The Sheffield TKV Tool was more accurate and precise compared to the other methods with no bias for either the left or right kidneys
SD standard deviation, KV kidney volume, TKV total kidney volume
*Results for Ellipsoid method is shown only for class 1 (typical) patients (51 patients)
For MIROS, no separate volumes were obtained for the left and left kidneys, thus results are reported for total kidney volume (TKV)