Abstract
PurposeThe interdisciplinary German guidelines for the diagnosis and treatment of internal carotid artery stenosis (ICAS) recommend a multiparametric approach for the sonographic grading of extracranial ICAS. The aim of this study is to evaluate the interrater and intermethod agreement of this elaborated sonographic approach with different angiographic modalities.MethodsPatients with extracranial ICAS were examined twice with colour-coded duplex sonography (CDS) by two experienced vascular neurologists. Each of the ten criteria and the resulting stenotic value were assessed. Grading of ICAS based on the multiparametric ultrasound criteria was compared with different angiography modalities (magnetic resonance angiography (MRA), computed tomography angiography (CTA), digital subtraction angiography (DSA)).ResultsSeventy-four consecutive patients with 91 extracranial ICAS were recruited from our stroke unit and neurovascular outpatient clinic. Interrater agreement for each single ultrasound criterion ranged from moderate to excellent (for the peak systolic velocity). Concerning the absolute stenotic value of ICAS, an excellent agreement between both ultrasound examiners with an ICC of 0.91 (range 0.87–0.94; p < 0.001) was found. In 96% of ICAS, the difference between the stenotic values was ≤ 10%. Intermethod agreements between CDS and DSA, CTA, and MRA were also good for both sonographers.ConclusionStrictly adhering to the multiparametric “DEGUM ultrasound criteria”, we found an excellent interrater agreement and a good intermethod agreement compared with angiography for the sonographic grading of extracranial ICAS. Thus, multiparametric CDS is in particular suitable for the follow up of extracranial ICAS even when examinations are done by different sonographers.
Highlights
While imaging modalities for the detection and grading of extracranial internal carotid artery stenosis (ICAS) directly visualise the stenosis by luminal sparing of the contrast agent as in computed tomography angiography (CTA), contrast-enhanced magnetic resonance angiography (CE-MRA), digital subtraction angiography (DSA) or three-dimensional ultrasound [4, 5], colour-coded duplex sonography (CDS) relies on haemodynamic changes caused by the stenosis
The aim of this study was to prospectively assess the interrater agreement for the multiparametric sonographic grading of extracranial ICAS as a whole and for each single main and additional criterion, and to compare the stenotic values obtained by these multiparametric ultrasound criteria with the stenotic values measured by CTA, CE-MRA, and DSA
We found an excellent agreement between both ultrasound examiners concerning the stenotic value of ICAS with an intraclass correlation coefficient (ICC) of 0.91
Summary
Since patients with an at least moderate (≥ 50% distal diameter reduction percentage according to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) [1])CR and AW contributed 20, 04103 Leipzig, Germany symptomatic extracranial internal carotid artery stenosis (ICAS) harbour a substantially increased risk of early ischemic stroke recurrence after the index event [2], the early identification and correct grading of extracranial ICAS is of utmost importance in the work up of acute ischaemic stroke [3].While imaging modalities for the detection and grading of extracranial ICAS directly visualise the stenosis by luminal sparing of the contrast agent as in computed tomography angiography (CTA), contrast-enhanced magnetic resonance angiography (CE-MRA), digital subtraction angiography (DSA) or three-dimensional ultrasound [4, 5], colour-coded duplex sonography (CDS) relies on haemodynamic changes caused by the stenosis. 20, 04103 Leipzig, Germany symptomatic extracranial internal carotid artery stenosis (ICAS) harbour a substantially increased risk of early ischemic stroke recurrence after the index event [2], the early identification and correct grading of extracranial ICAS is of utmost importance in the work up of acute ischaemic stroke [3]. Neuroradiology (2021) 63:519–528 which depends on the experience of the sonographer and technical equipment [7, 8] The reason for this might be the lack of widely accepted ultrasound criteria; ultrasound parameters and cut-off values for the sonographic detection and grading of ICAS differ between ultrasound labs [9]. CDS of the extracranial carotid arteries is routinely performed in ischaemic stroke patients in the acute setting in the hospital and in the outpatient care. A recent study even questioned this elaborated approach of grading ICAS in particular in comparison with CTA [11]
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