Original articleDetection and characterization of unruptured intracranial aneurysms: Comparison of 3 T MRA and DSA☆
Introduction
The management of patients with unruptured intracranial aneurysms (UIA) requires evaluating the balance between the risk of aneurysm rupture and treatment related morbidity and mortality [1], [2], [3]. Rupture risk is influenced by intrinsic aneurysm characteristics (e.g. location or morphology) [4], [5] and other factors such as gender, autosomal dominant polycystic kidney disease, personal or familial history of aneurysmal subarachnoid haemorrhage [6].
Digital subtraction angiography (DSA) remains the gold standard imaging method for the detection and morphological evaluation of IA [7]. However, DSA is an invasive, time consuming and expensive procedure associated with a low but significant risk of neurological deficit [8]. Magnetic resonance angiography (MRA) is a non-invasive alternative method for UIA evaluation and is now considered the first line method for the follow-up of endovascular treatment of IA with coils and/or stents [9]. At 1.5 Tesla (T), MRA has a high sensitivity for the detection of aneurysms ≥ 3 mm [10], [11], [12], [13]. However, all but one study at 1.5T [10] have compared MRA to conventional DSA without 3D rotational angiography (3DRA) that detects more very small IA [14], [15]. On the other hand, MRA presents a major limitation because it remains inferior to DSA for aneurysm morphological characterization [16]. Indeed, precise information on IA morphology is mandatory for patient triage between endovascular coil embolization and surgical clipping. Thanks to the development of MR imaging at 3 T, the diagnostic performance of MRA has been improved by optimizing the signal-to-noise ratio as well as spatial and contrast resolutions [17], [18], [19], [20], [21]. The aim of this study was to compare MRA at 3 T – including time-of-flight (TOF) and contrast enhanced (CE) techniques – and DSA including 3DRA for the detection and characterization of UIA.
Section snippets
Population
This study has been approved by our local ethical committee and written informed consent has been obtained from all patients. Between February and August 2010, we prospectively included all patients referred for one or multiple saccular UIA at our interventional neuroradiology consultation. Forty-one patients were identified of whom one patient was excluded because she refused to undergo DSA. There were 31 women and 9 men with a mean age of 52 years (range, 21 to 73 years old).
Imaging
MR angiography
Results
Mean delay between DSA and MRA was 21.5 days whereas the median delay was one day.
Discussion
This study shows that MRA at 3 T has a high sensitivity for the detection of UIA. Moreover, its sensitivity is equal to that of DSA for aneurysms ≥ 3 mm. However, MRA remains inferior to DSA for the characterization of UIA.
Conclusion
MR angiography at 3 T has a high sensitivity – equal to that of DSA for IA ≥ 3 mm – for the detection of UIA. However, it remains significantly inferior to DSA for morphological characterization of UIA.
Disclosure of interest
The authors declare that they have no conflicts of interest concerning this article.
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2017, Revue NeurologiqueCitation Excerpt :In addition, recent work has shown that even aneurysms < 5 mm can accurately be imaged with a 3-Tesla magnet [88]. However, MRA limitations include its lower sensitivity for small aneurysms and, as with CTA, its inferior ability to characterize UIA morphology [89]. Nevertheless, overall, the lack of radiation with MRA without a need for contrast-media injections and its adequate detection capacity makes it the preferred option for screening UIAs and, even more so, their follow-up (which should be performed under similar scanning conditions).
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2017, Journal of NeuroradiologyCitation Excerpt :Besides, DCE-MRA scan has 3-phase images, which could make the vascular shunt more easily observed. However, neither DCE-MRA nor CTA can provide the same high temporal and spatial resolution as readily as DSA can [22,23]. DCE-MRA may still have limitations in classifying DAV shunts according to the patterns of venous flow.
- ☆
These results have been orally presented at the 11th congress of the WFITN (8–11 November 2011, Cape Town, South Africa).