Transcranial color-coded duplex sonography reliably identifies intracranial vasculopathy in adult patients with sickle cell disease.

In order to prevent stroke, screening for disease-related intracranial vasculopathy using Doppler ultrasound is recommended in sickle-cell disease (SCD) children. How to screen such vasculopathy in adults remains largely unknown. The objective of this study was to assess whether transcranial color-coded duplex sonography (TCCD) is sensitive and specific enough to identify SCD adult patients with vasculopathy, compared with magnetic resonance angiography (MRA). Sickle cell disease adults followed in referral centers at high risk of vasculopathy were included in this study. Transcranial color-coded duplex sonography examination and 3-D time-of-flight MRA were performed on the same day. On MRA, vasculopathy was defined by the presence of at least one ≥50% arterial stenosis. On TCCD, vasculopathy was defined by a time-averaged mean of the maximum velocity (TAMx) stenotic/prestenotic ratio ≥ 3, an occlusion, or a Moyamoya pattern. Vasculopathy was also considered as present when TAMx ratio could not be calculated because of the presence of severe cervical lesions. Among 80 included patients, quality of MRA was insufficient in three patients. Among the 38 patients with vasculopathy on MRA, 37 had a vasculopathy according to TCCD criteria: TAMx ratio ≥ 3 or intracranial occlusion in 33 patients and cervical lesion in four patients. A Moyamoya pattern was identified with TCCD in all 17 patients with Moyamoya on MRA. Sensitivity and specificity of TCCD to identify patients with ≥50% vasculopathy on MRA were (n = 37/38) 97% and (n = 28/34) 82%, respectively. Positive and negative predictive values were (n = 37/43) 86% and (n = 28/29) 97%, respectively. Note, TCCD may be used to identify SCD adult patients with vasculopathy.

Optimal 4DFlow MR sequence parameters for the assessment of internal carotid artery stenosis: a simulation study.

PURPOSE: In patients with ICA stenosis, increased peak systolic velocity is a marker of stenosis at risk of ischemic stroke. 4DFlow MRI is a reproducible technique to evaluate velocities in ICA stenosis, although it seems to underestimate velocities as compared with Doppler ultrasonography. The purpose of our study was to confirm that velocities were underestimated on a new set of data acquired with a clinical 4DFlow sequence, and to devise optimal acquisition parameters for ICA stenosis exploration based on a numerical simulation. METHODS: After review board approval, 15 healthy controls and 12 patients presenting ICA stenosis were explored with Doppler ultrasonography and 4DFlow MRI. We created a 2-dimensional simulation of ICA stenosis and its corresponding 4DFlow acquisition, and compared its mean peak systolic velocity underestimation to real MRI and Doppler. We then simulated the acquisition for voxel size ranging from 0.5 to 1.25 mm and number of phases per cardiac cycle ranging from 10 to 25. RESULTS: On acquired data, 4DFlow MR underestimated peak systolic velocities (mean difference between Doppler and 4DFlow: - 35 cm/s), especially high velocities. With spatial and temporal resolutions equivalent to MR acquisition, our simulation yielded similar underestimation (mean difference: - 31 cm/s, P = 0.30). Simulations showed that 0.7-mm resolution and 20 phases per cardiac cycle would be necessary to record peak systolic velocities up to 250 cm/s. CONCLUSION: Higher spatial resolution can provide accurate peak systolic velocities measurement with 4DFlow MRI, thus allowing better ICA stenosis assessment. Further studies are needed to validate the proposed parameters.

Restenosis is more frequent after carotid stenting than after endarterectomy: the EVA-3S study.

BACKGROUND AND PURPOSE: Carotid angioplasty and stenting (CAS) may be more often associated with residual or recurrent stenosis than carotid endarterectomy (CEA). We compared the rates of restenosis in patients treated with CAS or CEA in the EVA-3S trial. METHODS: Five hundred seven patients (242 treated by CAS and 265 by CEA) had carotid ultrasound follow-up (mean carotid ultrasound follow-up, 2.1 years) according to a predefined protocol. Carotid restenosis of 50% to 69% was diagnosed on planimetry, whereas carotid restenosis of ≥70% or occlusion was diagnosed using either planimetry or velocity criteria. RESULTS: The rate of carotid restenosis of ≥50% or occlusion was significantly higher after CAS (12.5%) than after CEA (5.0%; time ratio, 0.16; 95% CI, 0.03-0.76; P=0.02). The rates of severe restenosis of ≥70% or occlusion were low and did not differ significantly between the 2 groups (3-year rates are 3.3% in the CAS group and 2.8% in the CEA group). Age at baseline was the only vascular risk factor significantly associated with carotid restenosis. Our study could not detect any effect of carotid restenosis on ipsilateral stroke. CONCLUSIONS: The short-term rate of carotid restenosis of ≥50% or occlusion is ≈2.5-times more common after CAS than after CEA, a difference accounted for by an excess risk in moderate restenosis. More data with longer follow-up are needed to assess the rates of late severe restenosis and to determine the relation between restenosis and recurrent stroke over time.

Asymmetry of intracranial internal carotid artery on 3D TOF MR angiography: a sign of unilateral extracranial stenosis.

The purpose of this case-control study was to determine whether an asymmetry of size of the intracranial internal carotid artery (ICA) on 3D time-of-flight MR angiography (MRA) is predictive of a high-grade cervical ICA stenosis. Ninety-six stroke/TIA consecutive patients were recruited for the study, of whom 32 had unilateral high-grade ICA stenosis (>or=70% NASCET) and were included into the case group, and the remaining 64 did not have such high-grade stenosis and were included in the control group. On intracranial MRA, two observers, blinded to the characteristics of cervical ICA stenosis, independently searched for qualitative size asymmetry between ICAs and measured the cross-sectional surface of the intracranial ICAs. An intracranial size asymmetry was seen in 28 of the 32 high-grade stenoses by both readers, and in 10 (reader(1)) and 8 (reader(2)) of the 64 controls (sensitivity =88%, specificity =84-88%). In patients without agenesia of the A1 segment of the circle of Willis (n=70), sensitivity was >or=90% and specificity =96%. Surfaces ratios were significantly different (p<0.001) between cases and controls. However, using ROC curves analysis, the quantitative processing did not improve the detection when compared with the qualitative assessment of intracranial ICA asymmetry. A size asymmetry of the intracranial ICAs reveals the presence of an underlying high-grade cervical stenosis, with a high degree of confidence, especially in patients without anatomical variant of the anterior part of the circle of Willis. This sign may allow an early detection of high-grade cervical carotid stenosis in stroke patients before dedicated neck imaging is performed.