Original Research Three-Dimensional Dynamic Time-Resolved Contrast-Enhanced MRA Using Parallel Imaging and a Variable Rate k-Space Sampling Strategy in Intracranial Arteriovenous Malformations Mina Petkova, MD, 1 Jean-Yves Gauvrit, MD, PhD, 2 * Denis Trystram, MD, 1 Franc ¸ois Nataf, MD, 1 Sylvie Godon-Hardy, MD, 1 Thierry Munier, MSc, 3 Catherine Oppenheim, MD, PhD, 1 and Jean-Franc ¸ois Meder, MD, PhD 1 Purpose: To evaluate the effectiveness of three-dimen- sional (3D) dynamic time-resolved contrast-enhanced MRA (TR-CE-MRA) using a combination of a parallel im- aging technique (ASSET: array spatial sensitivity encod- ing technique) and a time-resolved method (TRICKS: time-resolved imaging of contrast kinetics) and to com- pare it with 3D dynamic TR-CE-MRA using ASSET alone in the assessment of intracranial arteriovenous malfor- mations (AVMs). Materials and Methods: Twenty consecutive patients with angiographically confirmed AVMs were investigated using both 3D dynamic TR-CE-MRA techniques. Examinations were compared with respect to image quality, spatial reso- lution, number and type of feeders and drainers, nidus size, presence of early venous filling and temporal resolution. Digital subtraction angiography was used as standard of reference. Results: The higher temporal and spatial resolution of 3D dynamic TR-CE-MRA TRICKS ASSET allowed a better assessment of intracranial vascular malformations, namely better depiction of feeders, drainers and better detection of early venous drainage. There was no signif- icant difference between them in terms of nidus size. Conclusion: 3D dynamic TR-CE-MRA combining parallel imaging and a time-resolved method with subsecond and submillimeter resolution could become the first-line inves- tigation technique in both diagnosis and follow-up of intra- cranial AVMs. Key Words: 3D dynamic time-resolved contrast-enhanced MRA; TRICKS; intracranial arteriovenous malformation; digital subtraction angiography. J. Magn. Reson. Imaging 2009;29:7–12. © 2008 Wiley-Liss, Inc. INTRA-ARTERIAL DIGITAL SUBTRACTION ANGIOG- RAPHY (IA-DSA) remains the reference standard for diagnosis, treatment planning, and posttherapeutic monitoring of intracranial arteriovenous malformations (AVMs). However, it is an invasive procedure that in- volves ionizing radiation and the use of iodinated con- trast medium, and is associated with significant mor- bidity and mortality as patients with AVMs undergo multiple IA-DSAs; the neurological complication rate has been reported to be between 0.5% and 2% (1,2), with permanent neurological deficits occurring in 0.5% of cases (3). The high spatial and temporal resolution of IA-DSA is essential to demonstrate an abnormal com- munication between the arterial and venous systems, determine nidus size and the number and type of feed- ers and drainers, and detect the presence of vascular aneurysm or stenosis. Several MRA methods have been developed as a noninvasive alternative to IA-DSA. Time- of-flight (TOF), phase-contrast and contrast-enhanced (CE) magnetic resonance angiography (MRA) produce static images of AVMs and suffer from T1 shortening artifact from hemoglobin breakdown products. Fur- thermore, TOF MRA is insensitive to slow flow because of saturation effects. Recent methods such as two-di- mensional (2D) and three-dimensional (3D) dynamic CE time-resolved MRA (TR-MRA) tend to overcome these limitations and they demonstrate a good correla- tion with IA-DSA with respect to the Spetzler-Martin classification (4 –12). Compared with 2D acquisition, 3D dynamic TR-CE-MRA is superior in terms of spatial resolution, partial volume artifacts, signal-to-noise ra- tio (SNR) and volume coverage (13). One means of im- proving the spatial resolution of TR-CE-MRA is to use 1 Department of Neuroradiology and Neurosurgery, Sainte-Anne Hospi- tal, Paris 5 University, Paris, France. 2 Department of Neuroimaging, Pontchaillou Hospital, Rennes, France. 3 General Electric Healthcare Technologies, Buc, France. *Address reprint requests to: J.Y.G., Department of neuroimaging, Pontchail- lou Hospital, Rennes, France. E-mail: jean-yves.gauvrit@chu-rennes.fr Received November 3, 2007; Accepted May 21, 2008. DOI 10.1002/jmri.21483 Published online in Wiley InterScience (www.interscience.wiley.com). JOURNAL OF MAGNETIC RESONANCE IMAGING 29:7–12 (2009) © 2008 Wiley-Liss, Inc. 7