Inaccuracy of angiography in the diagnosis of carotid ulceration.

Abstract

SUMMARY It is generally stated that ulceration of the carotid bifurcation plaque may give rise to embolization and symptoms of cerebral ischemia. It has been suggested that prophylactic carotid endarter ectomy is indicated in asymptomatic patients if the angiogram is interpreted as showing ulceration.We therefore determined the accuracy of the radiologic diagnosis of ulceration by comparing the radiologic and morphologic findings in 155 carotid endarterectomies. Ulceration was diagnosed in 54% of the angiograms and 47% of the surgical specimens and was not related to the degree of stenosis. Angiography had a sensitivity of 73 %, a specificity of 62% and an overall accuracy of 67%. For the non-flow-restrictive lesions these figures were 65%, 66%, and 66%. If surgery were based on the angiographic diagnosis of ulceration in plaques with less than 50% stenosis, 16 out of 42 operations (38%) would have been done unnecessarily. Variability of the angiographic diagnosis of ulceration is also shown by a high interobserver variability; two sets of two authors read the angiograms independently and disagreed in 24% of the cases. The decision to operate should not depend entirely upon the angiographic diagnosis of ulceration.

Comparison of Carotid Plaque Ulcer Detection Using Contrast-Enhanced and Time-of-Flight MRA Techniques

“…1,4 Although catheter-based angiography historically has been considered the reference standard for carotid artery assessment, it is limited for identifying ulcers. [5][6][7] Noninvasive imaging modalities now offer stenosis measurements with comparable accuracy [8][9][10][11] and improved ulcer detection. 8 CTA provides superior spatial resolution to that achievable by MRA, but the exposure to ionizing radiation and the reduction in diagnostic accuracy due to wall calcification 12 has reinforced the appeal of MRA for carotid disease.…”

Histological Correlates of Carotid Plaque Surface Morphology on Lumen Contrast Imaging

“…Unfortunately, the majority of studies that are referenced as comparisons of carotid angiographic plaque surface morphology with "pathology" have assessed only the gross macroscopic appearance of the plaque surface recorded by the surgeon at endarterectomy (Table 1). 5,6,[11][12][13][14][15][16][17][18][19][20] The surgeons were not generally blinded to the angiographic appearance, and it is uncertain how these macroscopic assessments correlate with the underlying histology. 1 To the best of our knowledge, there have been no large detailed studies comparing angiographic plaque surface morphology with histological appearance.…”

Carotid plaque morphology and risk for stroke.

“…The degree of stenosis can be adequately assessed and measured with this technique, 22 -23 but the evaluation of plaque surface ulceration is subject to a high degree of interobserver variability, probably because of the biplanar characteristics of the images. 24 This observation is particularly true for small ulcers. 22 Plaque histology and intraplaque hemorrhage are outside the scope of angiography.…”