Table 1.

Correlation between the attenuation patterns of common bile duct stones on multidetector computed tomography and stone type (n = 111)

	Stone type, n (size, mean ± SD, mm)
Attenuation patterns	Black pigment	Mixed cholesterol	Brown pigment	Pure cholesterol	Overall
Heavily calcified	15	14	5	0	34
	(6.1 ± 3.4)	(7.0 ± 3.2)	(9.2 ± 4.1)		(6.9 ± 3.5)
Radiopaque	3	12	16	0	31
	(7.0 ± 1.0)	(10.2 ± 4.3)	(13.6 ± 4.8)		(11.6 ± 4.8)
Less radiopaque1	3	10	33	0	46
	(5.7 ± 4.0)	(7.6 ± 3.5)	(9.9 ± 5.1)		(9.1 ± 4.8)
Overall	21	36	54	0
	(6.2 ± 3.1)	(8.2 ± 3.6)	(10.9 ± 5.1)

¹Including six less radiopaque stones with gas attenuation. P < 0.001.