Changes in Tumor Volume and SUVs on 18F-FDG PET Before and After Chemotherapy: Status of Metabolic Response (According to EORTC) and Histologic Response in Control and Ifosfamide-Treated Rats
| Group | Rat ID | Prechemotherapy SUVmax | Postchemotherapy SUVmax | Relative SUVmax change | Prechemotherapy total tumor volume (mm3) | Postchemotherapy total tumor volume (mm3) | Relative tumor volume change | Metabolic response | Histologic response |
|---|---|---|---|---|---|---|---|---|---|
| Control | A-2 | 21.4 | 21.3 | 0% | 2,886 | 8,093 | 180% | SMD | 3 (10%−40%) |
| A-3 | 21.1 | 23.7 | 12% | 2,200 | 10,280 | 367% | SMD | 3 (10%−40%) | |
| A-5 | 21.1 | 33.1 | 57% | 2,006 | 5,517 | 175% | PMD | 3 (10%−40%) | |
| A-6 | 23.6 | 22.6 | −4% | 1,122 | 5,134 | 358% | SMD | 3 (10%−40%) | |
| A-7 | 23.3 | 20.7 | −11% | 1,659 | 8,506 | 413% | SMD | 3 (10%−40%) | |
| A-1 | 20.3 | 30.7 | 51% | 2,309 | 9,203 | 299% | PMD | 4 (>40%) | |
| A-4 | 20.8 | 23.1 | 11% | 1,918 | 12,909 | 573% | SMD | 4 (>40%) | |
| A-8 | 14.8 | 23.0 | 55% | 1,953 | 13,367 | 584% | PMD | 4 (>40%) | |
| A-9 | 20.8 | 27.7 | 31% | 1,828 | 10,129 | 454% | PMD | 4 (>40%) | |
| A-10 | 19.0 | 30.6 | 61% | 1,210 | 8,590 | 610% | PMD | 4 (>40%) | |
| Mean values | 20.6 (±2.4) | 25.7 (±4.5) | 26% (±28) | 1,909.1 (±515) | 9,172 (±2,692) | 401% (±157) | |||
| Ifosfamide | B-1 | 25.2 | 11.8 | −53% | 2,635 | 1,680 | −36% | PMR | 1 (<5%) |
| B-2 | 30.1 | 12.9 | −57% | 1,923 | 1,265 | −34% | PMR | 1 (<5%) | |
| B-4 | 27.3 | 10.4 | −62% | 1,844 | 733 | −60% | PMR | 1 (<5%) | |
| B-5 | 24.7 | 13.2 | −47% | 3,025 | 1,365 | −55% | PMR | 1 (<5%) | |
| B-6 | 32.2 | 13.1 | −59% | 1,435 | 492 | −66% | PMR | 1 (<5%) | |
| B-3 | 21.6 | 15.6 | −28% | 926 | 264 | −71% | PMR | 2 (5%−10%) | |
| B-7 | 33.0 | 20.3 | −38% | 4,427 | 2,719 | −39% | PMR | 2 (5%−10%) | |
| B-8 | 28.7 | 20.5 | −29% | 3,247 | 1,727 | −47% | PMR | 2 (5%−10%) | |
| B-9 | 34.5 | 26.3 | −24% | 3,461 | 1,184 | −66% | PMR | 2 (5%−10%) | |
| B-10 | 23.7 | 17.1 | −28% | 2,669 | 1,082 | −59% | PMR | 2 (5%−10%) | |
| Mean | 28.1 (±4.3) | 16.1 (±5) | −43% (±15) | 2,559 (±1,046) | 1,251 (±701) | −53% (±3) |
Metabolic response as evaluated according to EORTC: PMD = progressive metabolic disease (tumor SUV increase > 25%); SMD = stable metabolic disease (tumor SUV increase < 25% or tumor SUV decrease < 15%); PMR = partial metabolic response (tumor SUV decrease > 25%). Relative SUVmax change was calculated for each animal as follows: [(postchemotherapy SUVmax − prechemotherapy SUVmax)/prechemotherapy SUVmax] × 100.