Changes of Time-Attenuation Curve Blood Flow Parameters in Patients with and without Carotid Stenosis

C.-J. Lin; F.-C. Chang; W.-Y. Guo; S.-C. Hung; C.-B. Luo; J. Beilner; M. Kowarschik; W.-F. Chu

doi:10.3174/ajnr.A4239

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Fig 1.
Anteroposterior (A) and lateral (B) views of parametric color-coding of quantitative DSA. A, The ROI of the ICA is located at the midpoint of the cervical portion of the ICA. The ROI of M1 is located at the midpoint of the first segment of the middle cerebral artery. The sigmoid sinus ROI is located at the midpoint of the ipsilateral sigmoid sinus. The jugular vein ROI is located in the internal jugular vein at the same level as the ICA ROI. B, The ICA ROI is located in the cavernous portion of the ICA. The M2 ROI is located in the insular branch of the MCA. The PV ROI is located in the outlet of the parietal vein. The SSS ROI is located 2 cm above the confluence of the SSS.
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Fig 2.
Time-attenuation curves of lateral view DSA in a healthy subject. The blue curve represents the TDC of the ROI in the cavernous portion of the ICA. Tmax is the time point at which the ROI reaches maximal intensity. The MS of an ROI is defined by the maximal tangential slope located between arrival time and Tmax. FWHM is the width of the waveform at the level of half maximum concentration.
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Fig 3.
Receiver operating characteristic curves of all significantly different rTmax values (A), all significantly different MS values (B), and all significantly different FWHM values (C) in differentiating patients with stenosis from control groups.
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Fig 4.
TDC of lateral views of angiography are from a healthy individual (A) and a patient with 80% carotid stenosis (B). Both green lines are TDCs of M2. The rTmax of M2 in the patient with stenosis is 0.34 seconds, which was more prolonged than that (0.27 seconds) in the healthy individual. The FWHM of M2 (2.9 seconds) in the patient with stenosis is longer than that (1.8 seconds) in the healthy individual. The ICA (dark blue curves), sigmoid sinus (red curves), and internal jugular vein (light blue curves) all demonstrate prolonged rTmax and are right-shifted in the patient with stenosis. These delayed and dispersed phenomena of angiographic TDCs are consistent with those observed in MR imaging and CT perfusion imaging.

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Table 1:

Patient characteristics for groups A and B

	Group A (Stenosis)	Group B (Healthy)	P Value
No.	70	56
Age (yr)	73.6 ± 11.6	65.6 ± 10.2	<.001^{^a}
Heart rate (beats/min)	69.9 ± 17.2	72.6 ± 12.3	0.312
Blood pressure (mm Hg)	92.8 ± 19.9	97.6 ± 18.5	0.124
Stenotic degree (%)	81.4%	NA	NA
Prior minor stroke	19 (27%)	1 (1.7%)	<.001^{^a}

Note:—NA indicates not applicable.
↵a Statistically significant (t test, P < .05). There was no measurable stenosis in the healthy (control) population.

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Table 2:
Correlation of degree of stenosis with rTmax, MS, and FWHM^{^a}
rTmax MS FWHM
Degree of stenosis (%) M2 (0.380) M1 (0.486)^{^b} PV (−0.448)^{^b}
PV (0.280) SS (0.222) SSS (−0.238)
SSS (0.272) JV (0.264) M1 (−0.305)
Note:—SS indicates sigmoid sinus; JV, internal jugular vein.
↵a ROIs demonstrating statistically significant Pearson correlations are listed in each cell (correlations are given in parentheses).
↵b These 2 parameters were mildly correlated (r > 0.4).

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Table 3:

Comparison of group A and B values for rTmax, MS, and FWHM for 6 different ROIs

ROI	Group A	Group B	P Value
ROI	Stenosis (n = 70)	Healthy (n = 56)	P Value
rTmax
M2	0.77 ± 0.52	0.58 ± 0.32	.005^{^a}
PV	5.08 ± 1.32	4.38 ± 1.38	.001^{^a}
SSS	6.35 ± 1.79	5.44 ± 1.44	.001^{^a}
M1	0.66 ± 0.31	0.46 ± 0.46	.001^{^a}
SS	6.71 ± 1.91	5.91 ± 1.67	.004^{^a}
JV	7.29 ± 1.77	6.60 ± 1.62	.008^{^a}
MS
M2	337.15 ± 166.18	390.39 ± 166.98	.03^{^a}
PV	159.34 ± 73.36	170.56 ± 99.95	.43
SSS	103.78 ± 57.8	134.38 ± 111.07	.03^{^a}
M1	331.59 ± 144.43	454.44 ± 320.48	.003^{^a}
SS	100.32 ± 58.22	97.02 ± 47.17	.699
JV	116.78 ± 63.13	136.22 ± 109.63	.185
FWHM
M2	2.54 ± 1.14	2.09 ± 0.70	<.001^{^a}
PV	2.84 ± 2.37	2.74 ± 1.65	.74
SSS	3.49 ± 2.38	3.86 ± 0.75	.607
M1	3.57 ± 1.90	2.78 ± 0.92	.002^{^a}
SS	4.33 ± 1.83	3.72 ± 1.17	.61
JV^{^b}	NA	NA	NA

Note:—SS indicates sigmoid sinus; JV, internal jugular vein.
↵a Statistically significant difference (t test, P < .05).
↵b The FWHM of the JV was not applicable because the DSA acquisition terminated before the waveform of the JV dropped in most cases.

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Table 4:

Cutoff values of 10 significant TDC parameters for detecting stenosis flow with optimized sensitivity and specificity

ROI Variable	AUC	P Value	Cutoff Value	Sensitivity	Specificity
rTmax
M2	0.638 (0.555–0.722)	.002	0.415	83.6%	37.6%
PV	0.615 (0.53–0.701)	.011	4.905	55.2%	63.4%
SSS	0.655 (0.57–0.74)^{^a}	.001	6.895	55.2%	73.7%
M1	0.663 (0.58–0.746)^{^a}	.001	0.45	81.0%	58.2%
SS	0.582 (0.495–0.669)	.045	7.42	73.5%	91.2%
JV	0.589 (0.503–0.676)	.045	7.77	63.7%	84.9%
MS
M2	0.606 (0.517–0.695)	.02	511.5	89.6%	21.8%
M1	0.689 (0.608–0.77)^{^a}	.041	378.3	66.7%	60.0%
SSS	0.636 (0.547–0.725)	.002	90.5	55.1%	75.5%
FWHM
M2	0.609 (0.52–0.699)	.013	3.45	57.1%	67.7%
M1	0.679 (0.59–0.77)^{^a}	.001	3.40	57.1%	78.4%