Quiescent interval low angle shot magnetic resonance angiography of the extracranial carotid arteries

Abstract

Purpose To test the feasibility of a quiescent interval low-angle shot (QLASH) sequence for nonenhanced MR angiography (MRA) of the extracranial carotid arteries at 3 T. Methods The extracranial carotid arteries were imaged using QLASH MRA in healthy volunteers and patients with carotid arterial disease. The impact of three gating strategies (electrocardiographic-gated, pulse-gated, ungated) was evaluated. Image quality comparisons were made with respect to two-dimensional (2D) time of flight (TOF) MRA in volunteers and patients and contrast-enhanced MRA (CEMRA) in patients. Stenoses in patients were graded. Results QLASH MRA displayed the entire extent of the extracranial carotid arteries from their origins to the skull base. Electrocardiographic-gated QLASH MRA provided better image quality than pulse-gated and ungated implementations (P < 0.05) as well as 2D TOF MRA (P < 0.05). For grading of disease, QLASH MRA showed almost perfect agreement with CEMRA (Cohen's kappa = 0.86, P < 0.001) in a small cohort of patients with carotid arterial stenosis. Conclusion QLASH MRA allows for evaluation of the entire extent of the extracranial carotid arteries with an average scan time of less than 6 min and better image quality than 2D TOF. Initial clinical results in this pilot study suggest that QLASH has potential utility as a nonenhanced alternative to CEMRA.