Measurement system that improves the accuracy of polyp size determined at colonoscopy

Table 1 Comparison of the methods for measuring the largest diameter (n = 192)

Method	Size (cm)	P
		VC	CE	DGBF
VC	0.85 ± 0.69	-	-	-
CE	1.10 ± 0.53	< 0.001	-	-
DGBF	0.87 ± 0.54	0.134	< 0.001	-
ELMS	0.85 ± 0.53	0.289	< 0.001	0.027

Data are expressed as mean ± SD. CE: Clinicians’ evaluation; DGBF: Disposable graduated biopsy forceps; ELMS: Endoscopic lesion measurement system; VC: Vernier caliper.

Table 2 Comparison of the ratio of actual to estimated measurement (n = 192)

Ratio	Size (cm)	P
		DGBF:VC	ELMS:VC
CE:VC	1.30 ± 0.33	< 0.001	< 0.001
DGBF:VC	1.11 ± 0.37	-	0.021
ELMS:VC	1.04 ± 0.13	-	-

Data are expressed as mean ± SD. CE: Clinicians’ evaluation; DGBF: Disposable graduated biopsy forceps; ELMS: Endoscopic lesion measurement system; VC: Vernier caliper.

Table 3 Influence of tumor size on measurement accuracy

Polyp size	Method	Rate of accurate estimation	P
			CE	DGBF
< 1 cm	CE	20.6% (28/134)	-	-
	DGBF	61.2% (82/134)	< 0.001	-
	ELMS	75.4% (101/134)	< 0.001	0.001
1-2 cm	CE	14.0% (6/43)
	DGBF	48.8 % (21/43)	< 0.001
	ELMS	74.4% (32/43)	< 0.001	0.003
> 2 cm	CE	0.0% (0/15)
	DGBF	40.0% (6/15)	0.008
	ELMS	80.0% (12/15)	0.046	0.212

CE: Clinicians’ evaluation; DGBF: Disposable graduated biopsy forceps; ELMS: Endoscopic lesion measurement system.