Table 1.
Characteristics of study and validation cohortsa
| Study (n=25) | Validation (n=84) | |
|---|---|---|
| Age (years) | 68 (63–72) | 71 (64–77) |
| Male gender | 18 (72) | 38 (45)e |
| Ethnicityb | ||
| Caucasian | 17 (60) | 50 (60) |
| Asian | 3 (12) | 19 (22) |
| Other | 5 (20) | 15 (18) |
| Tumor diameter (cm)b | 2.3 (1.7–2.9) | 2.5 (1.9–3.8) |
| Procedure | ||
| Wedge Resection | 1 (4) | 12 (14) |
| Lobectomy | 24 (96) | 61 (72) |
| Other | 0 (0) | 11 (13) |
| Stage | ||
| I-II | 24 (96) | 84 (100) |
| III-IV | 1 (4) | 0 (0) |
| Histology | ||
| Adenocarcinoma | 20 (80) | 60 (71) |
| Squamous | 4 (16) | 20 (24) |
| Other | 1 (4) | 4 (5) |
| PET to resection time (days) | 27 (9–45) | 28 (13–47) |
| Glucose level prior to PET (mg/dL) | 106 (100–108)f | 100 (95–108) |
| Time to scan (minutes) | 60 (60–71) | 60 (60–60) e |
| Injected dose (millicuries) | 14.5 (12.9–15.8) | 14.8 (13.5–16.4) |
| FDG uptake imaging features | ||
| Intensity metrics | ||
| SUVmax | 3.2 (2.6–7.4) | 5.9 (3.3–12.1) |
| SUVmedian | 1.8 (1.5–2.3) | 2.6 (1.8–4.2)e |
| SUVmean | 1.9 (1.7–2.8) | 2.9 (1.9–4.8) |
| SUV75% | 3.4 (1.9–3.4) | 3.2 (1.6–5.2) |
| SUV90% | 2.5 (2.2–4.7) | 4.3 (2.5–8.1) |
| SUVmin | 1.4 (1.2–1.6) | 1.8 (1.4–2.4)e |
| Distribution metrics | ||
| SUVkurtosis | -0.06 (-0.53–0.61) | -0.14 (-0.60–0.51) |
| SUVskew | 0.87 (0.66–1.2) | 0.83 (0.61–1.1) |
| SUVsigma | 0.48 (0.27–1.3) | 0.96 (0.47–2.2) |
| SUVvariance | 0.23 (0.07–1.7) | 0.92 (0.22–4.6) |
| Spatial metrics | ||
| SUVMTV (cm3) | 3.8 (2.0–13) | 6.7 (3.5–25) |
| SUVarea (cm2) | 11.6 (4.8–41) | 16.6 (8.1–59) |
| SUVpointsc | 67 (26–249) | 97 (46–342) |
| SUVTGV (cm3)d | 13 (4.0–30) | 22 (8.0–91) |
MTV=metabolic tumor volume; TGV=total glycolytic volume.
a
Continuous variables are shown with median and interquartile range and categorical variables with number and percent.
b
Kurtosis represents “peakedness” of FDG uptake, skew the deviation from a normal distribution, and sigma and variance the breadth of uptake distribution
c
Number of voxels used to generate MTV
d
Equivalent to the product of SUVmean and SUVMTV
e
p<0.05 between study and validationcohorts for these variables
f
for 10 of 25 patients where data was available.