Imaging Modalities to Diagnose Carotid Artery Occlusion

Abstract

Introduction: Carotid artery stenosis is a condition in which carotid artery, the large artery on either side of neck becomes blacked, and the blockage is made up of substance called plaque that is fatty cholesterol deposits. In recent decades, imaging advancements, progressing from 1D to 3D models, have transformed disease diagnosis and treatment decisions. This paper comprehensively reviews the technical evolution of carotid artery stenosis (CAS) diagnostic imaging modalities, including duplex ultrasound (DUS), computed tomography angiography (CTA), and magnetic resonance angiography (MRA). DUS is typically the initial CAS diagnostic tool, with MRA or CTA recommended for confirmation and procedural planning. The focus has shifted from stenosis quantification to plaque characterization, prompting development of advanced tools like Optical Coherence Tomography (OCT), Photoacoustic Tomography (PAT), and Infrared Thermography (IR). This progress enhances early detection and informs clinical decisions for effective CAS management.

Objectives: The aim of this study is to compare the diagnosis of carotid artery stenosis under CT, MRI and Doppler ultrasound.

Methods: MRI examination, Doppler Ultrasound: Utilizes a 5 to 10 MHz linear array transducer to assess carotid stenosis through peak systolic and end-diastolic velocities, employing pulsed-wave and colour Doppler imaging. CT Angiography (CTA): Involves intravenous injection of iodinated contrast, followed by scanning with multidetector CT scanners (0.5 to 1 mm slices) for 3D reconstruction, providing detailed images of carotid artery anatomy and pathology. Neurological Examination: Performed by neurologists to assess cranial nerve function, motor strength, coordination, reflexes, and sensation, aiding in the diagnosis and treatment planning of neurological deficits. Blood Pressure Monitoring: Utilizes automated oscillometer devices or manual sphygmomanometers to record systolic and diastolic pressures bilaterally, aiding in hypertension detection and cardiovascular risk assessment

Results: The use of intravenous ultrasound contrast enhances DUS performance. The combination of diagnostic methods allows for early and accurate diagnosis of carotid diseases.

Conclusions: In summary, advancements in diagnostic techniques for carotid artery occlusion have significantly improved precision and efficacy. From traditional methods to comprehensive assessments with computer-aided programs, sensitivity and specificity have been enhanced across various imaging modalities. While challenges like radiation exposure persist with Digital Subtraction Angiography, integrating non-contrast computed tomography with Doppler ultrasound offers a comprehensive evaluation. Ongoing technological advancements, including computer-based algorithms and intravenous ultrasound contrast, show promise in addressing limitations. Balancing accuracy, cost-effectiveness, and accessibility remains crucial for effective management, ultimately improving patient outcomes.