Heavy metal in radiology: how to reliably differentiate between lodged copper and lead bullets using CT numbers

European Radiology Experimental

Table 1 CT numbers of copper and lead bullets

Measurements			Mean ± standard deviation		Min	Max	Min	Max	SW test	t test
CT number	ROI position	Energy (kVp)	Copper bullets	Lead bullets	Copper bullets		Lead bullets		p value	p value
Mean	Core	80	12,584 ± 1,951	11,406 ± 1,724	9,041	17,535	8,312	15,227	0.448	0.836
		100	13,862 ± 1,729	12,315 ± 1,867	9,798	17,988	8,469	16,266	0.403	0.399
		120	14,462 ± 1,435	12,996 ± 1,959	10,654	17,243	8,133	16,869	0.610	0.155
		140	14,197 ± 1,300	13,514 ± 2,048	10,180	16,571	8,217	17,419	0.948	0.169
Max	Core	80	13,649 ± 2,368	11,945 ± 1,645	9,520	19,230	9,790	15,630	0.457	0.714
		100	14,734 ± 2,004	12,848 ± 1,692	10,440	19,510	10,480	16,460	0.609	0.629
		120	15,186 ± 1,639	13,586 ± 1,754	11,350	18,640	10,430	17,,090	0.463	0.347
		140	14,820 ± 1,389	14,054 ± 1,838	10,800	17,770	10,810	17,860	0.397	0.275
Mean	Edge	80	22,708 ± 3,360	25,488 ± 3,617	14,448	27,730	17,461	30,598	0.991	0.423
		100	23,295 ± 3,212	26,412 ± 3,136	15,897	28,579	18,956	30,660	0.975	0.888
		120	21,976 ± 3,036	26,751 ± 2,995	15,304	26,394	20,160	30,668	0.896	0.727
		140	20,272 ± 2,840	26,976 ± 2,880	13,854	24,828	20,000	30,665	0.460	0.532
Max	Edge	80	25,854 ± 4,045	27,251 ± 3,395	15,640	30,510	18,440	30,670	0.364	0.421
		100	25,934 ± 3,582	28,068 ± 2,731	17,600	30,700	21,160	30,680	0.734	0.733
		120	24,277 ± 3,248	28,340 ± 2,478	17,270	28,780	21,910	30,680	0.448	0.818
		140	22,290 ± 2,926	28,628 ± 2,226	15,930	26,340	22,340	30,680	0.168	0.655

Min Minimum value, Max Maximum value, ROI Region of interest; SW test Shapiro-Wilk test