Artikel
Non-enhanced magnetic resonance imaging of unruptured intracranial aneurysms at 7 Tesla: comparison to the gold standard
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Veröffentlicht: | 8. Juni 2016 |
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Gliederung
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Objective: To prospectively evaluate time-of-flight (TOF) magnetic resonance angiography (MRA) and magnetization-prepared rapid acquisition gradient-echo (MPRAGE) at 7 Tesla for delineation of unruptured intracranial aneurysms (UIAs) in comparison to digital subtraction angiography (DSA).
Method: Forty patients with single or multiple UIAs were enrolled in this trial. Sequences acquired at 7 Tesla were TOF MRA and non-contrast-enhanced MPRAGE. All patients additionally underwent 3D DSA. Two experienced raters individually analyzed the following five aneurysm and image features on a five-point scale in 2D and 3D image reconstructions: delineation of parent vessel, dome and neck; overall image quality; and presence of artifacts. Interobserver accordance was analyzed for all ratings.
Results: The study group comprised 40 neurosurgical patients (male n = 15, female n = 25; average age 58 years, standard error of the mean 1.6; range 38 - 80 years). All 7 Tesla MRI examinations and DSA were performed successfully without any relevant side effects. Both readers identified 64 UIA in all 2D and 3D image reconstructions of 7 Tesla TOF MRA and 7 Tesla MPRAGE imaging as well as in DSA. Combined 7 Tesla and DSA ratings were excellent without significant differences between the visualization methods. Both ratings were significantly higher than for all individual MRI reconstructions (2D TOF MRA, 3D TOF MRA, 2D MPRAGE and 3D MPRAGE) for all evaluated aneurysm and image features. Ratings for 2D MPRAGE and 3D TOF MRA were significantly lower, but still good to excellent for most evaluated aneurysm and image features. Evaluation of 2D TOF MRA and 3D MPRAGE resulted in the lowest ratings with a good average, but poor or non-diagnostic ratings for few specific aneurysms. For the majority of ratings (n = 27) interobserver accordance was almost perfect and the remaining ratings (n = 3) showed substantial interobserver accordance.
Conclusions: This study demonstrates excellent delineation of UIAs using 7 Tesla MRA within a clinical setting comparable to the gold standard, DSA. The combination of 7 Tesla non-enhanced MPRAGE and TOF MRA for assessment of untreated UIAs is a promising clinical application of ultra-high-field MRA.