Figure 1
Dynamic PET images of a small pulmonary nodule in the left upper lobe and corresponding time activity curve (TAC) of the nodule displayed by PMOD 3.409 software.
Figure 2
Patlak plot derived from the tissue time activity curve (TAC) and the input function (plasma TAC). The Patlak plot becomes linear after the tracer concentrations in reversible compartments and in plasma are in steady state.
Figure 3
(A) standardized uptake value (SUVmax), (B) Dynamic 18F-FDG PET/CT influx constant (Ki), (C) Perfusion CT parameters blood volume (BV) and (D) Average arterial flow (AF) of the benign and malignant nodules.
Table 1
The demographic data, average nodule size, standardized uptake value (SUVmax), metabolic parameter relating to the pulmonary nodules through dynamic 18F-FDG PET/CT, and perfusion parameters through perfusion CT for the benign and malignant nodules
| Benign Nodules | Malignant Nodules | p value | |
|---|---|---|---|
| Total Number of nodules | 9 | 12 | |
| Number of male patients (%) | 5/9 (55 %) | 6/12 (50 %) | |
| Average patient age (years ± SD) | 63 ± 7.5 | 68 ± 6.7 | |
| Average nodule size, range (mm) | 18, 9–29 | 22, 12–30 | |
| Average SUVmax 18F-FDG PET/CT ± SD | 2.2 ± 1.7 | 7.0 ± 4.5 | 0.0148 |
| Number of nodules analysed for dynamic 18F-FDG PET/CT | 7 | 9 | |
| Average Ki ± SD (min-1) | 0.0057 ± 0.0071 | 0.0230 ± 0.0155 | 0.0311 |
| Number of nodules analysed for perfusion CT parameters | 7 | 10 | |
| Average BV ± SD (Patlak, ml/100ml) | 11.6857 ± 6.7347 | 28.3400 ± 15.9672 | 0.0250 |
| Average AF ± SD (ml/100g/min) | 74.4571 ± 89.0321 | 89.2000 ± 49.8883 | 0.1613 |
Figure 4
Comparison of AUCs on ROC curves (A) SUVmax, SURBLOOD, SURLIVER, PET grade and (B) SURLIVER, Ki, BV and AF.
95% CI, p values for SUVmax / SURBLOOD / SURLIVER / PET grade / Ki / BV / AF: 0.6264 to 1.000, 0.0157/ 0.6486 to 1.000, 0.0105/ 0.6550 to 1.000, 0.0105/ 0.507 to 0.956, 0.0756/ 0.602 to 1.000, 0.0300/ 0.6322 to 1.000, 0.0248/ 0.4342 to 0.9944, 0.1432.
Table 2
Comparison of the diagnostic accuracy of different techniques and parameters with pre-specified and derived cut-point values for malignancy
| Parameter | Cut-point value/grade | Sensitivity (95% CI) | Specificity (95% CI) | Accuracy | |
|---|---|---|---|---|---|
| SUVmax | Pre-specified Derived | ≥ 2.5* ≥ 3.4 | 75.0% (46.8 to 91.1%) 75.0% (46.8 to 91.1%) | 66.7% (35.4 to 87.9%) 88.9% (56.5 to 99.43%) | 71.4% 81.0% |
| SURBLOOD | Pre-Derived specified | ≥ 1.56 | 83.3% (55.2 to 97.0%) | 88.9% (56.5 to 99.4%) | 85.7% |
| SURLIVER | Pre-specified Derived | ≥ 1.12 ≥ 1.65 | 83.3% (55.2 to 97.0%) 75% (46.8 to 91.1%) | 66.7% (35.4 to 87.9%) 88.9% (56.5 to 99.4%) | 76.2% 81.0% |
| SUV grade | Pre-specified & Derived | ≥ 3 | 66.7% (39.0 to 86.2%) | 77.8% (45.3 to 96.0%) | 71.4% |
| Ki | Derived | ≥ 0.01 min-1 | 77.8% (45.2 to 96.0%) | 85.7% (48.7 to 99.3%) | 81.3% |
| BV | Derived | ≥ 21 ml/100ml | 70% (39.7 to 89.2%) | 100% (64.6 to 100%) | 82.4% |
| AF | Derived | ≥ 65 ml/100g/min | 70% (39.7 to 89.2%) | 85.7% (48.7 to 99.3%) | 76.5% |
[i] * = adding cut-points standardized uptake value (SUVmax) ≥ 1.75 and ≥ 3.6 for nodules < 12 mm and > 16 mm, respectvely,37 resulted in sensitivity, specificity and accuracy of 72.7%, 70.0% and 71.4%, respectively;
AF = Arterial flow; BV = blood volume; CI = confidence interval; Ki = influx constant; SUR = SUV ratios; SUV = standardized uptake value