Power M-Mode Doppler and Single-Gate Spectral Analysis Using a 2-MHz Pulsed-Wave Doppler Transducer to Directly Detect Cervical Internal Carotid Artery Stenosis

Abstract

Background and Purpose-We hypothesized that direct cervical investigation with Power M-Mode Doppler (PMD) combined with single-gate Doppler spectral analysis (SGDSA) using a 2-MHz pulsed-wave Doppler transducer would show reasonable accuracy parameters when compared with standard color-coded carotid duplex ultrasound (CDU). Methods-We prospectively screened for cervical internal carotid artery (ICA) stenosis by direct observation using a 2 MHz PMD/SGDSA device. PMD identified the artery (location, depth, flow direction) and SGDSA assessed waveform; peak systolic, end diastolic, and mean flow velocities (MFV) of the common carotid artery; cervical ICA proximally and distally; and external carotid artery. Diagnostic accuracy was compared with concurrent carotid duplex ultrasound. The continuity principle was applied using the proximal/distal cervical ICA MFV ratio. Results-We examined 456 vessels (228 patients). Using ICA proximally/ICA distally MFV ratio of 1.5 or greater or absence of ICA signature, for 40% to 59% or greater stenosis (including occlusions), sensitivity was 75.4%, specificity 99.8%, positive predictive value 97.7%, negative predictive value 96.6%, and accuracy 96.7%. For MFV ratio 1.6 or greater or absence of ICA signature and 60% to 79% or greater stenosis (including occlusions), sensitivity was 92.3%, specificity 98.1%, positive predictive value 81.8%, negative predictive value 99.3%, and accuracy 97.6%. Conclusions-Use of combined PMD and SGDSA to directly observe the extracranial ICA is reasonably accurate compared with carotid duplex ultrasound. Using the MFV ratio of proximal/distal extracranial ICA improves accuracy parameters and provides a quick and effective bedside screen for ICA stenosis. This novel technique should be considered part of the standard PMD/transcranial Doppler examination.

Prevalência de estenose carotídea em pacientes com indicação de cirurgia de revascularização miocárdica

“…In Brazil, there has been a single report with a 50-individual sample and the rate was 48% and 32% in patients with CS ≥50 and ≥70%, respectively The screening can also aid the diagnosis and follow-up of cases that have an indication for conservative treatment, because the CS is a risk marker itself that persists regardless of its treatment 31 and an opportunity to observe the vascular health in general 32 . To prevent the CVA, the identification and quantification of the CS are of utmost importance 33 .…”

Applications and Advantages of Power Motion-Mode Doppler in Acute Posterior Circulation Cerebral Ischemia

“…Our group and other investigators have described potential applications and advantages of PMD-over single-gate TCD in detecting acoustic windows 12 and microembolic flow signatures, 13 in diagnosing acute middle cerebral artery occlusions, 14 and for evaluating cervical internal carotid artery stenosis. 15 In the present study, we aimed to evaluate the diagnostic accuracy of PMD-TCD against angiography for the detection of acute posterior circulation stenoocclusive arterial disease.…”

A novel method to quantify carotid artery stenosis by Doppler ultrasound: Using the continuity principle

“…Few studies in the current medical literature used the continuity principle to calculate the percentage stenosis. In the studies by Popa et al (7) and Ranke et al (8), the authors claimed that the continuity principle was used but, in fact, only the velocity ratios, not the diameters, were taken into account.…”