Peer-review started: October 10, 2016
First decision: December 13, 2016
Revised: December 17, 2016
Accepted: January 11, 2017
Article in press: January 14, 2017
Published online: February 28, 2017
Processing time: 142 Days and 13.4 Hours
To demonstrate feasibility of vessel wall imaging of the superficial palmar arch using high frequency micro-ultrasound, 7T and 3T magnetic resonance imaging (MRI).
Four subjects (ages 22-50 years) were scanned on a micro-ultrasound system with a 45-MHz transducer (Vevo 2100, VisualSonics). Subjects’ hands were then imaged on a 3T clinical MR scanner (Siemens Biograph MMR) using an 8-channel special purpose phased array carotid coil. Lastly, subjects’ hands were imaged on a 7T clinical MR scanner (Siemens Magnetom 7T Whole Body Scanner) using a custom built 8-channel transmit receive carotid coil. All three imaging modalities were subjectively analyzed for image quality and visualization of the vessel wall.
Results of this very preliminary study indicated that vessel wall imaging of the superficial palmar arch was feasible with a whole body 7T and 3T MRI in comparison with micro-ultrasound. Subjective analysis of image quality (1-5 scale, 1: poorest, 5: best) from B mode, ultrasound, 3T SPACE MRI and 7T SPACE MRI indicated that the image quality obtained at 7T was superior to both 3T MRI and micro-ultrasound. The 3D SPACE sequence at both 7T and 3T MRI with isotropic voxels allowed for multi-planar reformatting of images and allowed for less operator dependent results as compared to high frequency micro-ultrasound imaging. Although quantitative analysis revealed that there was no significant difference between the three methods, the 7T Tesla trended to have better visibility of the vessel and its wall.
Imaging of smaller arteries at the 7T is feasible for evaluating atherosclerosis burden and may be of clinical relevance in multiple diseases.
Core tip: The evaluation of smaller arteries in the hand may be clinically useful in a variety of vascular diseases. Imaging the vessel wall of such small caliber arteries (2.5 mm to 3.1 mm) requires very high spatial resolution and the use of either high frequency micro-ultrasound or 7 Tesla magnetic resonance imaging (MRI) would be the ideal tool to acquire these images. We sought to demonstrate feasibility of vessel wall imaging of the superficial palmar arch using 7T and 3T MRI in comparison with very high frequency micro-ultrasound.