Photon-counting CT of elbow joint fractures: image quality in a simulated post-trauma setting with off-center positioning

European Radiology Experimental

Table 3 Detailed quality assessment

			Fracture assessment rating value (mean [min−max])			Trabecular bone assessment rating value (mean [min−max]
Kernel	Position	Dose protocol	PCD-CT	EID-CT	p value	PCD-CT	EID-CT	p value
Br76/Ur77	OH	2 mGy	4.0 [4−4]	3.5 [3−4]	0.002	4.0 [4−4]	1.3 [1−2]^a	< 0.001
		6 mGy	6.5 [6−7]	3.8 [3−4]	< 0.001	6.0 [6−6]	3.3 [3−4]	< 0.001
		12 mGy	7.0 [7−7]	4.6 [4−5]	< 0.001	6.5 [6−7]	3.8 [3−4]	< 0.001
	ABD	2 mGy	2.5 [2−3]	1.0 [1−1]^b	< 0.001	2.5 [2−3]	1.0 [1−1]^b	< 0.001
		6 mGy	3.2 [3−4]	1.9 [1−2]^a	< 0.001	3.2 [3−4]	1.2 [1−2]^a	< 0.001
		12 mGy	6.4 [6−7]	3.7 [3−4]	< 0.001	5.6 [5−6]	1.8 [1−2]^a	< 0.001
Br89/Ur89	OH	2 mGy	2.3 [2−3]	1.0 [1−1]^b	< 0.001	1.0 [1−1]^b	1.0 [1−1]^b	1.0
		6 mGy	4.3 [4−5]	1.0 [1−1]^b	< 0.001	5.0 [5−5]	1.0 [1−1]^b	< 0.001
		12 mGy	7.0 [7−7]	2.7 [2−3]	< 0.001	6.7 [6−7]	1.2 [1−2]^a	< 0.001
	ABD	2 mGy	2.0 [2−2]	1.0 [1−1]^b	< 0.001	1.0 [1−1]^b	1.0 [1−1]^b	1.0
		6 mGy	2.3 [2−3]	1.0 [1−1]^b	< 0.001	1.7 [1−2]^a	1.0 [1−1]^b	< 0.001
		12 mGy	6.5 [6−7]	1.0 [1−1]^b	< 0.001	5.8 [5−6]	1.0 [1−1]^b	< 0.001

Quality assessment by two readers for 10 cadaveric specimens (mean value, min−max) for fracture and trabecular bone on a 7-point rating scale. The subjective evaluation was better for PCD-CT compared to EID-CT for almost all scan protocols. The p value of the Wilcoxon signed rank test analysis is reported
^aRating scale value: 1 (nondiagnostic), 2 (very poor)
^bRating scale value: 1 (nondiagnostic). ABD Abdominal scanning position, EID-CT Energy-integrating detector computed tomography, OH Overhead scanning position, PCD-CT Photon-counting detector computed tomography