ABSTRACT
Introduction: The new 3 Tesla (T) magnetic resonance (MR) scanners yield improved signal-to-noise ratio and spatial resolution with superior background suppression compared to lower field strength systems. This is advantageous for MR angiograms. The purpose of our study was to compare unenhanced three-dimensional time-of-flight magnetic resonance angiography (3D TOF MRA) at 3T with catheter digital subtraction angiography (DSA) in detecting unruptured intracranial aneurysms. Materials and Methods: Out of 1375 consecutive patients who underwent unenhanced 3D TOF MRA at 3T, 15 patients with unruptured intracranial aneurysms were retrospectively identified. Nine of these 15 patients had DSA as the reference standard for comparison. Aneurysm size, location and morphology were independently assessed on both MRA and DSA by 2 radiologists. Results: Seventeen aneurysms ranging in size from 1 mm to 24 mm were identified in 15 patients on MRA. DSA confirmed the aneurysms in 9 patients with good anatomical correlation compared with the MRA findings. Conclusions: 3D TOF MRA at 3T has good correlation with DSA and aneurysms as small as 1 mm in size can be detected. This can be a promising, non-invasive method for aneurysm surveillance.
The recent advent of 3 Tesla (T) very high field magnetic resonance (MR) systems into clinical practice has enabled a variety of exciting developments in both clinical and research applications. The main advantage of 3T MR imaging is increased signal-to-noise ratio (SNR), which increases in an approximately linear fashion with field strength in the range of 1.5T to 3.0T.1 This increased SNR improves spatial resolution and potentially enables MR angiography (MRA) at 3T to rival catheter digital subtraction angiography (DSA), traditionally regarded as the gold standard, for the evaluation of intracranial vascular disease. Apart from the improved SNR, there is superior background suppression and excellent fat suppression at 3T, resulting in improved visualisation of the intracranial vessels. The purpose of our study was to compare unenhanced three-dimensional time-of-flight magnetic resonance angiography (3D TOF MRA) at 3T with DSA in detecting unruptured intracranial aneurysms.
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