Comparison of magnetic resonance angiography, duplex ultrasound, and digital subtraction angiography in assessment of extracranial internal carotid artery stenosis.

Abstract

The results of a prospective study comparing ultrasound, intra-arterial digital subtraction angiography, and magnetic resonance angiography in the assessment of the degree of extracranial internal carotid artery stenosis are reported in patients with symptoms of recent carotid territory ischaemia. A total of 70 patients and 137 vessels were examined by all three techniques. The results obtained by each technique were reported blind. The mean difference (SD) for the comparison of magnetic resonance angiography and digital subtraction angiography was -0-7 (14)%, for ultrasound and digital subtraction angiography 3-1 (15)%, and for magnetic resonance angiography and ultrasound -3-8 (15)

Internal carotid artery stenosis: comparison of duplex scan and magnetic resonance angiography with digital subtraction angiography

“…The NASCET method 9 was used to measure IC stenosis, except when there was a signal gap, indicating severe stenosis that makes it impossible to directly measure the artery diameter. In these cases, as described previously 14 , a 90% stenosis was diagnosed, except when reduced flow distal to stenosis was found, in which case a value of 99% stenosis was attributed. Intracranial arteries were assessed by MRA and DGA, because severe stenosis in these vessels may contraindicate endarterectomy [9][10][11][12]28 .…”

“…Digital angiography (DGA) is the standard method to evaluate IC stenosis and to indicate endarterectomy [8][9][10] . However, there is a 1 to 4% risk of stroke or death related to this method 6,13,14 . Also, there is some error related to DGA, as shown when inter-observer concordance is assessed [14][15][16] .…”

“…Also, there is some error related to DGA, as shown when inter-observer concordance is assessed [14][15][16] . The present study compares two non-invasive procedures to DGA, attempting to reduce the risks and costs attributed to DGA, as other authors have done before 14,[16][17][18][19][20][21][22][23] .…”

“…There is also a report distinguishing only occlusion and sub-occlusion 16 . Continuos numeric variables were also compared 14 . There is no agreement about the accuracy of non-invasive methods in the various studies.…”

“…There is no agreement about the accuracy of non-invasive methods in the various studies. Some showed bad results 16,18,20,23 , while others obtained good correlation with only limited restrictions, mainly in cases of IC sub-occlusion or when DS and MRA disagree 14,17,19,21,22 .…”