Keywords:
Arteries / Aorta, Vascular, Computer applications, Ultrasound, Ultrasound-Colour Doppler, CT-Angiography, Diagnostic procedure, Computer Applications-Detection, diagnosis, Contrast agent-intravenous, Arteriosclerosis, Ischaemia / Infarction, Blood
Authors:
V. Rafailidis1, I. Chryssogonidis1, E. Grisan2, T. Tegos1, D. Rafailidis1, P. Sidhu2, A. Charitanti-Kouridou1, P. Prassopoulos1; 1Thessaloniki/GR, 2London/UK
DOI:
10.26044/ecr2019/C-0162
Results
In total,
54 patients (72.2% male,
median age of patients: 61 years) with 62 internal carotid artery plaques (mean stenosis 68.9%) were included in the present study.
Median (IQR) of SII-CDU for plaques without and with an ulceration detected on MDCTA were 10.6 (7.3) and 11.9 (16.5) respectively.
Mean (SD) of SII-CEUS for plaques without and with an ulceration were 11.7 (5.6) and 24.3 (13.9).
The respective boxplots can be found in Fig. 2. The SII-CDU did not significantly differ between non-ulcerated and ulcerated plaques based on Mann-Whitney U test (p=0.162) while SII-CEUS did significantly differ (p=0.001),
confirming better delineation of ulcerations with CEUS ( Table 1 ).
ROC analysis was performed to determine whether CDU or CEUS is better to quantitatively characterize carotid plaque surface irregularities in order to detect ulceration,
as defined by the reference method of CTA.
SII-CEUS was found to have a greater area under the curve (0.798) as compared with SII-CDU (0.624) for detecting CTA-confirmed ulceration.
The upper and lower 95% confidence intervals of the Area Under the Curve (AUC) are presented in Table 2,
while the ROC curves in Fig. 3.
Screening,
optimal and diagnostic cut-off values were defined for SII-CDU as 4.7,
8.1 and 22.3 respectively.
The respective resulting sensitivity and specificity for the detection of ulceration were 92.9% and 12.5%,
78.6% and 35.4%,
35.7% and 97.9%.
For SII-CEUS,
the cut-off values defined were 8.7 (screening),
13.9 (optimal) and 24.2 (diagnostic),
yielding sensitivity and specificity values of 92.9% and 27.1%,
78.6% and 70.8%,
35.7% and 97.9% respectively.
CEUS was thus superior to CDU for the detection of ulcerated carotid plaques by quantifying surface irregularities.
Examples of SII quantification of smooth and ulcerated carotid plaques can be found in Fig. 4 and Fig. 5 respectively.
The limitations of the study include the relatively small number of patients examined as well as a potential spectrum bias as only plaques with moderate or severe stenosis have been recruited.
Furthermore,
the two-dimensional nature of the US technique used in this study may affect the diagnostic accuracy for the detection of ulcerations.
It is obvious that 3D US would better and more thoroughly characterize plaque surface morphology but this technique is not yet widely available.