World J Nephrol Urol

World Journal of Nephrology and Urology, ISSN 1927-1239 print, 1927-1247 online, Open Access

Article copyright, the authors; Journal compilation copyright, World J Nephrol Urol and Elmer Press Inc

Journal website http://www.wjnu.org

Original Article

Volume 1, Number 1, February 2012, pages 23-28

The Efficiency of Non-Contrast Computed Tomography in the Estimation of Urinary Stone Composition

Tables

**Table 1.** A Comparison of the Stone Types With Regard to Age
	CaP (n:34)	CaO (n:11)	Struvite (n:5)	P
CaP: calcium phosphate; CaO: calcium oxalate.
Age	51.7 ± 14.4	42.6 ± 12.5	63.0 ± 10.7	0.024

**Table 2.** A Comparison of the Stone Types With Regard to Gender
	CaP Number (%)	CaO Number (%)	Struvite Number (%)	P
CaP: calcium phosphate; CaO: calcium oxalate.
Female	7 (20.6)	2 (18.2)	2 (40)	0.620
Male	27 (79.4)	9 (81.8)	3 (60)

**Table 3.** Values for HU, HUD and the Ratio of Maximum Stone Density to Stone Size Which Were Obtained by the Two Observers
	CaP	CaO	Strüvit	P
HU¹: Hounsfield Unit value measured by first observer; HU²: Hounsfield Unit value measured by second observer; HUD¹: Hounsfield Unit Density calculated by first observer; HUD²: Hounsfield Unit Density calculated by second observer; Max. HU/size¹: The ratio of maximum density to size calculated by first observer; Max. HU/size²: The ratio of maximum density to size calculated by second observer.
HU¹	1082 ± 403	845 ± 361	444 ± 194	0.002
HU²	1079 ± 417	853 ± 336	448 ± 188	0.003
HUD¹	61 ± 32	43 ± 26	40 ± 35	0.135
HUD²	61 ± 33	44 ± 28	39 ± 33	0.159
Max. HU/size¹	66 ± 32	47 ± 25	44 ± 38	0.137
Max. HU/size²	68 ± 35	50 ± 29	45 ± 35	0.194

**Table 4.** HUD Values Obtained by the Two Observers
	CaP	CaO	Struvit
HUD: Hounsfield Unit Density; cutoff value: 80.
HUD > 80	8	2	1
HUD < 80	26	9	4