Image Quality and Patient-Specific Organ Doses in Stone Protocol CT: A Comparison of Traditional CT to Low Dose CT with Iterative Reconstruction
Table 2
CT stone, noise, and quality characteristics between modalities.
FBP-CT
IR-CT
p value
(n=250)
(n=90)
+ Kidney Stone (%)
221
(88)
80
(89)
p = 0.9
Mean stone diameter, mm (SD)
5.8
(1.3)
5.1
(1.1)
p = 0.3
Kidney Stone Morphology (%)
p = 0.75
Single
192
(87)
73
(91)
Confluence
16
(7)
4
(5)
Partial staghorn
3
(1)
1
(1)
Full staghorn
10
(5)
2
(3)
+ Ureteral Stone (%)
53
(22)
28
(31)
p = 0.07
Mean stone diameter, mm (SD)
4.7
(1.0)
4.3
(0.9)
p = 0.4
+ Hydronephrosis (%)
48
(22)
24
(30)
p = 0.14
+ Bladder Stone (%)
13
(5)
7
(8)
p = 0.37
Mean stone diameter, mm (SD)
8.5 (2)
3.5
(0.8)
p = 0.09
Noise† (%)
p = 0.23
Minimal
188
(75)
61
(68)
Diagnostic
60
(24)
29
(32)
Excessive
2
(1)
0
(0)
Quality† (%)
p = 0.39
Excellent
141
(56)
42
(47)
Good
78
(31)
34
(38)
Acceptable
29
(12)
13
(14)
Suboptimal
1
(1)
1
(1)
Poor/Non-diagnostic
1
(1)
0
(0)
Key: CT, computed tomography; FBP, filtered back projection; IR, iterative reconstruction. SD, standard deviation; : 16 patients had kidney and one other stone location; † = interrater reliability (AC2) was high: AC2 for noise was 0.79, and AC2 for quality was 0.87.
