Cervical artery dissection: Improved diagnosis by B-Flow ultrasound

Objective: The objective of this study was to evaluate the efficiency of B-Flow ultrasound in diagnosing supraaortic vessel dissections compared with other ultrasound techniques including B scan, Color-Coded Doppler (CCDS) and Power Doppler (PD). Materials and methods: Eighty-eight patients with suspected arterial dissection of the neck vessels were included in this prospective trial. All patients were examined using B scan, Color-Coded Doppler sonography and Power Doppler. After documentation of the diagnoses, the patients were additionally examined by B-Flow ultrasound. Contrast-enhanced magnetic resonance angiography (MRA) was used as reference standard in all cases. Results: Dissections of the carotid artery (n=19) and of the vertebral artery (n=35) were found in 44 patients. B-Flow imaging identified 52 of 54 arterial dissections that were confirmed by MRA. There were no false-positive diagnoses in ultrasound examination. The sensitivity of ultrasound examination using B scan, CCDS and PD in detecting all dissections was 95.9% and 99.1% with additional B-Flow examination. Sensitivity using B-Flow increased from 98.3% to 100% for carotid dissections and from 93.3% to 94.3% for vertebral artery dissections. Due to the lack of overwriting artifacts, B-Flow imaging detected residual flow within the false lumen more precisely. The reduced effect of the ultrasound probe angle facilitated imaging of fissures, membranes and low flow phenomena and improved the identification of low-reflection wall structures. The cine mode of the B-Flow showed undulating membrane movement most clearly. Contrast-enhanced MRA in conjunction with axial T1 and T2 weighted sequences enabled the best visualization of intramural hematomas. Conclusion: B-Flow imaging can significantly increase the sensitivity of ultrasound examination for dissections of the neck vessels. It also improves the visualization of flow within the true and false lumen, of hypoechoic thrombi and of intramural hematoma.