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Intracranial aneurysms: evaluation by MR angiography
J S Ross1, T J Masaryk, M T Modic
1Department of Radiology, Western Reserve University, Cleveland, 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 degree 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. This noninvasive technique accurately visualizes the circle of Willis, aiding in early diagnosis of these vascular abnormalities.
Area of Science:
- Neuroradiology
- Medical Imaging
- Vascular Neurology
Background:
- Intracranial aneurysms pose significant health risks.
- Accurate and noninvasive diagnostic methods are crucial for early detection.
- Conventional angiography, while effective, is invasive.
Purpose of the Study:
- To compare the diagnostic accuracy of MR angiography (MRA) with intraarterial digital subtraction angiography (IA DSA) for intracranial aneurysms.
- To evaluate the effectiveness of MRA in visualizing the circle of Willis.
- To assess MRA's potential as a screening tool for at-risk patients.
Main Methods:
- Volume gradient-echo MR angiography (MRA) was performed on 47 patients.
- MRA findings were compared with IA DSA in 19 patients with confirmed aneurysms.
- Sensitivity and specificity were calculated for different MRA evaluation methods.
Main Results:
- MRA demonstrated increasing sensitivity with additional analysis techniques, reaching 86% with cine MRA plus partitions and spin-echo studies.
- For patients with aneurysms, sensitivity ranged from 73% (cine MRA only) to 95% (cine MRA + partitions + spin-echo).
- MRA successfully identified aneurysms as small as 3-4 mm in the circle of Willis.
Conclusions:
- MRA is a valuable tool for detecting intracranial aneurysms.
- The technique offers high sensitivity and specificity, especially with advanced analysis.
- MRA shows significant potential as a noninvasive screening examination for intracranial vasculature.