Carotid Contrast-Enhanced Magnetic Resonance Angiography
Printed with permission from ELSEVIER.
Neuroradiology Applications of High-Field MR Imaging – Guest Editor Winfried A. Willinek, MD
Neuroimaging Clinics of North America – Suresh K. Mukherji, MD Consulting Editor
Note: None of the major vendors have validated these protocols.
Fig. 1 (A) First-pass delayed elliptical-centric CE carotid 1.5 T MR. The 15x software presents the user with multiple variables to optimize the MR angiography acquisition. Note that the frequency and phase matrix allows for submillimeter in-plane resolution with a 28-cm FOV CE MR angiogram.angiography. (B) Advanced settings such as delayed elliptical-centric phase ordering and Turbo mode 2 can be found under the User CVs (control variables) screen
Fig. 2 A 0.54-mm3 resolution first-pass CE large FOV carotid MR angiogram using the GE 3 T MR750. (A) The summary page from the new 20x software presents the imaging parameters that may need to be modified based on patient body habitus. Note the 8-mm slice thickness of this higher resolution MR angiography technique compared with 1.5 T MR angiography. (B)Selecting the button in the upper right hand corner of the Summary page can expose the Details page. Note the higher spatial resolution matrix at 3 T compared with the 1.5 T MR protocol. (C) In the Vascular tab, the user can prescribe how many global maximum intensity projections to automatically generate. (D) Under the Advanced tab, the user has easy access to many important CVs, such as the method of phase reordering. We have found that delayed elliptical-centric phase reordering works best for first-pass CE carotid MR angiography.
Fig. 7 Using the Philips 1.5 Intera MR scanner for 0.66-mm3 resolution, first-pass CE large FOV carotid MR angiography. (A)The Contrast tab shows the choices of fast field echo with T1 weighting as well as shortest TR and TE. (B) The Geometry tab is where imaging options such as FOV, rectangular FOV, matrix size, and scan percentage can be modified. Also note that SENSE is not used at 1.5 T with this protocol.
Fig. 9 Using the Philips 3 T Acheiva MR scanner for 0.52-mm3 resolution first-pass CE large FOV carotid MR angiography. (A)Note how the large coverage in the AP direction simplifies prescription of the carotid CE MR angiography without the need for additional MR angiography localizers. (B) The Geometry tab details the use of 2D SENSE to achieve a 16-fold acceleration and allow for submillimeter in-plane resolution with the extended A-P coverage in a scan time of 1:07 minutes.
Fig. 12 Using the Siemens 32 channel Magnetom TIM Avanto for 0.65-mm3 resolution, first-pass CE large FOV carotid 1.5 T MR angiography. The imaging parameters for the 1.5 T first-pass high-resolution CE MR angiography are shown on the Resolution tab. The acceleration factors and spatial resolution are not as aggressive as their 3 T MR counterparts.
Fig. 14 Using Siemens 32 channel Magnetom TIM Trio for 0.44-mm3 resolution first-pass CE large FOV carotid, 3 T MR angiography.
Fig. 14 (A) Note the large FOV and wide coverage to simplify the placement of the 3D prescription. The excellent opacification of the aortic arch, great vessels, carotid artery, and vertebral artery also ensures that all these vessels are included in the high-resolution, first-pass CE MR angiogram.
Fig. 14 (B) The Resolution tab details many of the imaging parameters required to achieve the 0.44-mm3 voxel size.
Fig 14 (C) The Geometry tab specifies the FOV, percent phase FOV, slice thickness, and slices per slab.