Noncontrast‐enhanced four‐dimensional MR angiography for the evaluation of cerebral arteriovenous malformation: A preliminary trial

Abstract

Purpose: To prospectively evaluate noncontrast-enhanced (NCE), time resolved, four-dimensional (4D) magnetic resonance angiography (MRA) for assessment of cerebral arteriovenous malformation (AVM), with intraarterial digital subtraction angiography (DSA) performed as the reference standard. Materials and Methods:Fifteen patients (ten men, five women; age range 2-59 years, mean 29.4 years) with 15 untreated cerebral AVMs comprised the study population. NCE 4D MRA was performed on a 3.0 T MR scanner. MR images were reviewed by two independent readers and compared with DSA with respect to arterial feeders, nidus size, and venous drainage. Kappa coefficients of concordance were computed to determine the interobserver and intermodality agreements for the depiction of arterial feeders, nidus, and venous drainage between the two techniques.Results: Fifteen AVMs detected in DSA were visualized in NCE 4D MRA. Intermodality agreements were excellent for the arterial feeders (K ¼ 0.918, P ¼ 0.000), good for the nidus size (K ¼ 0.692, P ¼ 0.000), and moderate for the venous drainage (K ¼ 0.495, P ¼ 0.001).Conclusion: NCE 4D MRA is a promising and potentially valuable method for noninvasive assessment of angioarchitecture and hemodynamics of cerebral AVMs. Further improvement of labeling persistence is desirable in order to enhance the depiction of draining veins for AVMs.

Velocity‐selective magnetization‐prepared non‐contrast‐enhanced cerebral MR angiography at 3 Tesla: Improved immunity to B0/B1 inhomogeneity

“…For clinical applications, acquisition with isotropic resolution over a large spatial coverage within 5 min is desired. bSSFP has been used in many NCE-MRA studies, mostly at 1.5T (8,(13)(14)(15)18,21,22,47,48) and few at 3T (19,49), owing to its high SNR efficiency and inherent flow-compensation capability. The challenges of 3T, including off-resonance artifacts and high SAR, have made bSSFP more preferable at 1.5T (50).…”

Noncontrast dynamic MRA in intracranial arteriovenous malformation (AVM): comparison with time of flight (TOF) and digital subtraction angiography (DSA)

“…This modality has recently been tested clinically in the evaluation of intracranial collateral flow in patients with steno-occlusive diseases of brain-supplying arteries 20 . During the preparation of this manuscript, a similar study was conducted in 15 AVM patients, and the results showed that the consistency between non-contrast enhanced dMRA and DSA was excellent for the arterial feeders, good for the nidus size and moderate for the venous drainage 21 . Our data are consistent with the reported findings.…”

Noncontrast‐enhanced time‐resolved 4D dynamic intracranial MR angiography at 7T: A feasibility study

“…The relatively short bolus of labeled blood (∼1–2 sec) is a major limiting factor of 4D MRA and potentially hampers its clinical utility, especially at 1.5T and 3T. For instance, it remains a challenge to capture draining veins in AVM, which usually appear in later phases of dynamic MRA (after 1–2 sec) …”

“…For instance, it remains a challenge to capture draining veins in AVM, which usually appear in later phases of dynamic MRA (after 1-2 sec). 12,13 Recently, technical advances in both hardware and software of high-field MRI has enabled 7T MRI systems to become commercially available for human study. A number of MRI techniques, 3D anatomical and angiographic sequences in particular, have been developed and optimized at 7T to enable high-resolution acquisition by making use of the increased signal-to-noise ratio (SNR) at ultrahighfield.…”