Intravenous flat-detector computed tomography angiography for high-grade carotid stenosis

The significant feature of intravenous flat-detector computed tomography (IV FDCT) angiography is its role in neurointerventional setting without patient transfer. However, few studies have addressed the accuracy of IV FDCT in estimating carotid stenosis and length. This study examined the reliability of IV FDCT in the diagnosis of high-grade carotid stenosis and stenosis length with digital subtraction angiography (DSA) as the reference.

Intravenous flat-detector CT and DSA were conducted simultaneously for 33 patients with 42 stenosed carotid arteries who were suspected of having symptomatic high-grade stenosis by carotid duplex ultrasound, magnetic resonance angiography, or CT angiography. The degree of stenosis and length discrepancy between 2 tests were recorded by 2 readers.

The intraobserver and interobserver agreements were excellent for measuring high-grade carotid stenosis (κ = 0.87 and 0.82). Intravenous flat-detector CT had a sensitivity of 96.3%, specificity of 93.3%, and negative predictive value of 93.3% for detecting high-grade stenosis (≥70%) compared with DSA. Bland-Altman plots demonstrated excellent correlation of the degree of stenosis IV FDCT with DSA. Length discrepancy (IV FDCT - DSA, in millimeters) did not differ significantly according to degree of stenosis (Spearman rank test; r = 0.18, P = 0.26).

Intravenous flat-detector CT can be a feasible and time-saving test for evaluating high-grade carotid stenosis and stenosis length.