High‐resolution imaging of the intracranial arterial and venous systems following a single contrast injection

Abstract

Purpose: To generate two separate three-dimensional (3D) high spatial resolution images of the intracranial arterial and venous systems using a single contrast injection. Materials and Methods:A 3D contrast-enhanced (CE) magnetic resonance angiography (MRA) acquisition was modified to create two separate k-space data sets to encode the arterial and venous enhancement signals individually after contrast agent injection. Following an automated detection of contrast arrival, the central k-space views corresponding to the arterial phase were acquired for the first eight seconds. A full elliptical-centric acquisition was then acquired for the venous phase and the missing views in the periphery of the first k-space data set were copied from the venous phase. A total of 18 patients underwent this study. Image quality, signal-to-noise ratio (SNR), and contrast-tonoise ratio (CNR) were determined in both intracranial systems.Results: Two 3D image sets were generated for the arterial and venous intracranial systems. Both sets have high quality images that are clinically diagnostic. SNR and CNR were high in both sets, so that all the major vessels were visible. Conclusion:This technique provides images with high spatial resolution for both arterial and venous intracranial systems using a single contrast injection.

Quality-Evaluation Scheme for Cerebral Time-Resolved 3D Contrast-Enhanced MR Angiography Techniques

“…11,14,22,28,30,31,33 The type of artifacts, such as aliasing, ringing, movement, or vascular edge, must be specified because it is influenced by the TR-3D-CE-MRA strategy used. 11,35,[37][38][39] Arterial-to-venous separation, assessed with a semiquantitative scale, 5,11,12,30,34 provides a quick evaluation of the practical temporal resolution (ie, the ability of TR-3D-CE-MRA to detect rapid arteriovenous shunt involved in certain vascular malformations). However, our study shows no obvious interest in visually grading maximum arterial or venous SI.…”

“…4) Arterial-to-venous separation during the arterial phase. 5,12,21,30,34,35 Grading was as follows: 0, poor, Յ2 phases without venous contamination; 1, good, 3 phases without venous contamination; and 2, excellent, Ն4 phases without venous contamination. This parameter reflected the temporal resolution and determined the ability of the TR-3D-CE-MRA to identify the rapid arteriovenous shunt involved in most vascular malformations.…”

“…The second part was an anatomic vascular study, which evaluated the vascular visibility of vessels of different diameters, the visibility of the smallest reflecting spatial resolution, and from different territories. Most vessels were listed from the literature, 9,10,13,17,22,26,30,34 but some were added to complete the list. The visibility of venous drainage and of small-diameter arteries has important clinical implications because it can help to determine the risk of neurologic complications and the therapeutic strategy for vascular malformations.…”

Evaluating contrast kinetics by acquiring 2D images during 3D contrast‐enhanced MR angiography

“…3 that contrast signal intensity remains at high levels for long periods of time over three minutes. In this case, techniques could be used to reduce venous contamination, such as repeatedly encoding the low spatial frequency k-space data for the arterial and venous enhancement peaks (11).…”

Intracranial contrast‐enhanced magnetic resonance venography with 6.4‐fold sensitivity encoding at 1.5 and 3.0 Tesla

“…The imaging volume typically encompasses the patient's entire brain, and the use of a large sampling matrix is necessary to achieve the desired spatial resolution. Acquisition of these large data sets is usually not practical with TOF or PC MRV because of prohibitively long scan times, and even for conventional 3D CE-MRV, the duration can exceed 4 min (7,12).…”