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Intracranial aneurysms: evaluation by MR angiography
J S Ross1, T J Masaryk, M T Modic
1Department of Radiology, University Hospitals of Cleveland/Case Western Reserve University, OH 44106.
Abstract:
The purpose of this study was to compare the accuracy of a volume gradient-echo MR angiography (MRA) technique with that of intraarterial digital subtraction angiography (IA DSA) in the identification of intracranial aneurysms. The intracranial vasculature was examined in 47 patients by MRA and compared with IA DSA findings in 19 of these patients who had saccular or giant intracranial aneurysms. The remaining 28 patients, in whom no aneurysm was found, served as a control group. MRA was performed with the use of a velocity-compensated gradient-echo sequence (TR = 40-50/TE = 7-15) with a 15 degrees flip angle. The sensitivity and specificity were calculated for the evaluation of the cine 3D reconstructions (cine MRA) only, cine MRA + inspection of the individual partitions, and cine MRA + individual partitions + spin-echo studies. Of 21 aneurysms, of which three were missed in two patients, the sensitivity varied from 67% for cine MRA only to 86% for the cine MRA + partitions + spin-echo studies; of the 19 patients, among whom it was assumed that the diagnosis of any one aneurysm in a patient would lead to angiography and detection of additional aneurysms, the sensitivity varied from 73% for the cine MRA only to 95% for the cine MRA + partitions + spin-echo studies. The results of this study suggest that MRA can define the circle of Willis sufficiently to allow detection of intracranial aneurysms as small as 3-4 mm. MRA holds promise as a truly noninvasive screening examination of intracranial vasculature in patients at risk for aneurysms.
Insights
Magnetic Resonance Angiography (MRA) shows promise for detecting intracranial aneurysms, offering a noninvasive screening tool for at-risk patients. This technique can identify aneurysms as small as 3-4 mm in the circle of Willis.
Area of Science:
- Neuroradiology
- Medical Imaging
Background:
- Intracranial aneurysms pose a significant risk.
- Accurate and noninvasive diagnostic methods are crucial for early detection.
Purpose of the Study:
- To compare the diagnostic accuracy of MR angiography (MRA) with intraarterial digital subtraction angiography (IA DSA) for identifying intracranial aneurysms.
- To evaluate the effectiveness of different MRA techniques in aneurysm detection.
Main Methods:
- 47 patients underwent MRA using a velocity-compensated gradient-echo sequence.
- Findings were compared with IA DSA in 19 patients with confirmed aneurysms.
- Sensitivity and specificity were calculated for various MRA evaluation methods.
Main Results:
- MRA sensitivity ranged from 67% (cine MRA only) to 86% (cine MRA + partitions + spin-echo studies) for detecting aneurysms.
- In patients with aneurysms, sensitivity varied from 73% to 95% with advanced MRA techniques.
- MRA successfully visualized the circle of Willis, detecting aneurysms as small as 3-4 mm.
Conclusions:
- MRA is a promising noninvasive screening tool for intracranial aneurysms.
- Advanced MRA techniques significantly improve sensitivity and specificity in aneurysm detection.
- MRA can effectively define the circle of Willis for aneurysm screening.