A new method for segmentation of FDG PET metabolic @entity5 volume using the peritumoural halo layer and a 10-step colour scale. A study in @entity1 with XXXX .

@entity1 @entity3557 @entity5 @entity189 @entity343
AIM: We observed a layer between @entity5 activity and background on FDG PET/CT with the 10-step colour scale and the window level set properly. We named the layer peritumoral halo layer (PHL). We performed this study to establish the reliability of metabolic @entity5 volume (MTV) segmentation using PHL (MTVPHL) in @entity1 with @entity3557 . @entity1 , METHODS: Of a total of 140 @entity3557 ( @entity3557 ) @entity1 , 70 (50.0%) had FDG-avid @entity3557 . In these @entity1 , MTVPHL, MTV segmented according to fixed 50% SUVmax (MTV50%), and fixed SUV with 2.5 to 4.0 (MTV2.5 to MTV4.0) were compared with pathologic @entity5 volume ( @entity343 ). The absolute percentage difference between MTVPHL and @entity343 was compared in @entity189 (MPTC) and @entity189 (non-MPTC) subgroups. The % SUVmax and SUV thresholds of MTVPHL were compared with @entity5 SUVmax. RESULTS: Among the MTVs, MTV50% was not correlated with @entity343 (r = -0.16, p = 0.182) and was not reliable according to the Bland-Altman plot. Although MTV2.5, MTV3.0, MTV3.5, and MTV4.0 correlated with @entity343 (r = 0.85, 0.86, 0.87, and 0.87, respectively; p < 0.001), these MTVs were not reliable on Bland-Altman analyses. MTVPHL was significantly correlated with @entity343 (r = 0.80, p < 0.001), and the Bland-Altman plot did not show systemic error. The MTVPHL was more accurate in non-MPTC than in MPTC (p < 0.001), and the absolute % difference was smaller as @entity343 became larger (   = -0.65, p < 0.001). The MTVPHL thresholds had correlations with SUVmax (% SUVmax threshold:    = -0.87, p < 0.001; SUV threshold: r = 0.88, p < 0.001). CONCLUSIONS: MTVPHL was more reliable than MTV%SUVmax or MTVSUV. The reliability of MTVPHL improved with larger PTVs. The threshold of the MTVPHL was naturally altered by PHL according to SUVmax.
