Diagnostic Value of Carotid Plaque Assessment with AIS Based on Quantitative Parameters of Dual-Layer Detector Spectral CT

Figures & data

Table 1 Demographic and Clinical Information on the Study Population

Variables	AIS (n=41)	Non-AIS	tor χ^2	p
Demography
Age (years, x±s)	65.83±9.22	62.90±6.59	1.66	0.10
Men (n, %)	28 (68.3)	24 (57.1)	1.102	0.294
Vascular risk factors (n, %)
Hypertension	35 (85.4)	30 (71.4)	2.373	0.123
Diabetes	16 (39.0)	12 (28.6)	1.014	0.314
Hyperlipidemia	16 (39.0)	9 (21.4)	3.052	0.081
Coronary heart disease	3 (7.3)	6 (14.3)	0.446	0.504
Atrial fibrillation	3 (7.3)	0 (0)	1.434	0.231
Smoking	12 (29.3)	6 (18%)	2.742	0.098
Alcoholism	0 (0)	2 (4.8)		0.253
Baseline laboratory tests(x±s)
Triglyceride (mmol/L)	1.66±0.78	1.68±0.75	−0.104	0.917
Total cholesterol (mmol/L)	4.56±1.21	4.27±0.87	1.245	0.217
Low density lipoprotein (mmol/L)	2.94±0.90	2.76±0.98	0.887	0.378
High density lipoprotein (mmol/L)	1.18±2.84	1.13±0.26	0.830	0.409
Homocysteine (umol/L)	13.51±7.71	12.24±6.60	0.810	0.421
Fasting blood sugar (mmol/L)	7.14±3.60	6.00±2.16	1.753	0.084
White blood cell (*109/L)	6.79±1.63	6.16±1.31	1.948	0.055
BMI (kg/m2)	24.37±2.91	25.10±2.86	−1.145	0.256

Table 2 Comparison of Carotid Atherosclerotic Plaque Detection Between the Two Groups [n (%)]

Groups	Cases	Carotid Atherosclerotic Plaques
AIS	41	38 (92.7%)
Non-AIS	42	27 (64.3)
χ^2		9.851
p		0.002

Table 3 Comparison of Carotid Atherosclerotic Plaque Types Between the Two Groups [n (%)]

Plaque Types	AIS	Non-AIS	p
Non-calcified plaques	34(42.5%)	17(26.6%)	0.047
Mixed plaques	14(17.5%)	5(7.8%)	0.088
Calcified plaques	32(40.0%)	42(65.6%)	0.002
Totals	80	64

Table 4 Comparison of Carotid Plaque Energy Spectrum Parameters Between AIS and Non-AIS Groups (M, IQR)

Parameters	AIS	Non-AIS	z	p
λH	3.86 (0.59–19.42)	19.72 (1.63–23.02)	−2.631	0.009
Zeff	8.95 (7.62–12.01)	12.02 (8.15–12.58)	−2.820	0.005
ED	106.75 (103.70–133.68)	124.4 (105.56–139.56)	−2.547	0.011
Iodine no water	3.67 (0.53–17.73)	16.89 (1.39–21.95)	−2.979	0.003
Iodine density	0.47 (0–2.74)	0.53 (0.01–9.34)	−0.907	0.364

Abbreviations: λH, the slope of the spectral Hounsfield unit curve; Zeff, effective atomic number; ED, electron density.

Table 5 Optimal Diagnostic Thresholds and Diagnostic Efficacy of ROC Curve Analysis of Energy Spectrum Parameters for AIS

	λH	Zeff	ED	Iodine-No-Water
Thresholds	19.56	11.865	110.45	9.125
Sensitivity(%)	76.3(65.4–85.1)	72.5(61.4–81.9)	60(48.4–70.8)	61.3(49.7–71.9)
Specificity(%)	51.6(38.7–64.2)	56.2(43.3–68.6)	64.1(51.1–75.7)	65.6(52.7–77.1)
AUC	0.628(0.535–0.721)	0.637(0.553–0.715)	0.624(0.531–0.716)	0.645(0.561–0.772)

Abbreviation: AUC, area under the curve.

Figure 1 ROC curves of carotid plaques leading to the development of AIS as assessed by quantitative parameters (λH, Zeff, ED, and Iodine no water) of spectral CT.

Figure 2 True-false-positive and true-false-negative results for the diagnosis of the subjects of this study using the cut-off values of the energy spectrum curves(λH).

Figure 3 True-false-positive and true-false-negative results for the diagnosis of the subjects of this study using the cut-off values of iodine no water.

Figure 4 True-false-positive and true-false-negative results for the diagnosis of the subjects of this study using the cut-off values of effective atomic number (Zeff).

Figure 5 True-false-positive and true-false-negative results for the diagnosis of the subjects of this study using the cut-off values of electron density(ED).