*2.5. Ground Truth*

The final diagnosis was provided by histology, long-time follow-up, and/or as a consensus decision of the institutional interdisciplinary tumor board.

#### *2.6. Statistical Analysis*

Differences in the mean values of two groups, features, or methods were tested for significance using the two-sided Student's *t*-test. Levene's test was performed to assess the equality of variance before the *t*-tests.

One-way ANOVA was performed to compare the dignity (inflammation, benign, or malign) of the different groups for the studied metrics (e.g., DV-FDGmean, MR-FDGmean). An alpha level of 0.05 was used for analysis. Subsequent multiple comparison correction was performed using Tukey's honestly significant difference procedure. Results of the ANOVA are shown with *p* values in the main manuscript. Correlation coefficients were calculated according to Pearson and a Pearson correlation coefficient of r > 0.7 was defined as strong, 0.7–0.3 as moderate, and <0.3 as a weak linear correlation. A *p*-value < 0.05 was considered statistically significant.

The intersection of the false-negative and false-positive rates was defined as the optimal cut-off value. Statistical analysis was performed with SPSS Statistics 28.0 software (IBM Inc., Armonk, NY, USA), MATLAB v. R2022b (The MathWorks, Inc., Natick, MA, USA), and MS Excel 2019 v.2206 (Microsoft corporation, Redmond, WA, USA).

#### **3. Results**

#### *3.1. Patient Cohort*

Thirty-nine patients met the inclusion criteria for this prospective study between October 2019 and April 2022, of whom 34 consented to study-related dynamic PET acquisition. One patient received further treatment abroad and dropped out of the analysis. Consequently, 33 patients with complete datasets were included in the analysis. Gender distribution was 42% women (14/33) and 58% men (19/33). Male patients were significantly older (68 ± 9 yrs vs. 60 ± 10 yrs, respectively, *p* = 0.032) and taller (178 ± 9 cm vs. 161 ± 9 cm, respectively, *p* < 0.001) than female patients with comparable weight (78 ± 22 kg vs. 70 ± 10 kg, respectively, *p* = 0.053) and BMI (26 ± 6 vs. 27 ± 4, respectively, *p* = 0.475). The blood glucose level before tracer administration did not differ between the sexes and was 5.44 ± 0.94 mmol/L.
