Table 3.

Spearman correlation between texture features and the most commonly used positron emission tomography quantitative metrics. The table shows variable degree of associations being higher and moderate correlation coefficient

Moderate correlation
Variable	Correlation coefficient (Spearman’s rho, ρ)
	TLG
	4	8	16	32	64
Intensity variability	0.529	0.519	0.530	0.565	0.581
Run-length variability	0.632	0.700	0.677	0.670	0.681
Maximum SUV	0.530	0.530	0.528	0.527	0.530
Mean SUV	0.502	0.502	0.500	0.502	0.502
SUV variance	0.583	0.583	0.579	0.587	0.583
SUV SD	0.582	0.582	0.546	0.590	0.582
Surface area
Entropy	–0.526	–0.531	–0.520	–0.553	–0.543
Homogeneity	0.543	0.545	0.527	0.560	0.539
Inverse difference moment	0.543	0.547	0.531	0.557	0.504
Tumour volume	0.635	0.635	0.627	0.641	0.635
MTV
Long-run emphasis	0.5	0.501	0.588	0.672	0.634
Low-intensity long-run emphasis	0.5	0.503	0.593	0.677	0.636
Surface area	0.635	0.635	0.627	0.641	0.635
SUVmean
SUV variance	0.655	0.655	0.636	0.653	0.655
TLG	0.502	0.502	0.501	0.502	0.502
SUVmax
TLG	0.530	0.530	0.525	0.527	0.530

TLG – total lesion glycolysis, SUV – standardised uptake value, MTV – metabolic tumour volume