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Magnetic resonance signal intensity and volume changes after endovascular treatment of intracranial aneurysms causing
M Tsuura1, T Terada, Y Nakamura
1Department of Neurological Surgery, Wakayama Medical College, Japan.
Abstract:
To determine when and how intracranial aneurysms causing mass effect change following endovascular treatment, we used MRI to assess patients for 2-3 years after the interventional procedure. Nine patients who had aneurysms compressing the surrounding structures underwent endovascular treatment. Proximal occlusion of the parent artery was performed in seven cases, and in two the aneurysm was embolised with microcoils. After embolisation, signal intensity within aneurysms tended to be high on both T1- and T2-weighted images. When there was rapid reduction in size high-signal zones within aneurysms became isointense or gave low signal on T1-weighted images. On T2-weighted images, isointense or low-signal foci appeared within high-signal areas in the aneurysm, giving mixed intensity. In typical cases, the mean volume of the aneurysm fell to approximately 30% of its initial value 2-12 months after treatment. After this, no additional reduction was observed. The aneurysms which showed little signal intensity change tended to shrink more slowly and to a lesser degree than the more typical cases. Aneurysms which gave high signal on both T1- and T2-weighted images early following embolisation shrank more quickly than those showing little signal change.
Insights
Intracranial aneurysms treated with embolisation typically shrink significantly within 12 months. MRI signal changes predict the rate and extent of aneurysm volume reduction after endovascular treatment.
Area of Science:
- Neuroradiology
- Interventional Neurology
- Medical Imaging
Background:
- Intracranial aneurysms can cause mass effect, necessitating treatment.
- Endovascular treatment is a common approach for managing these aneurysms.
- Understanding post-treatment changes is crucial for patient management.
Observation:
- MRI was used to monitor nine patients with mass-effect-causing aneurysms post-endovascular treatment.
- Aneurysm signal intensity on T1- and T2-weighted MRI was assessed.
- Changes in aneurysm volume were tracked for 2-3 years.
Findings:
- High signal intensity on T1- and T2-weighted MRI post-embolisation correlated with faster shrinkage.
- Aneurysm volume typically reduced to 30% within 2-12 months, with no further significant reduction observed.
- Slower shrinkage was associated with less pronounced MRI signal changes.
Implications:
- Early MRI signal intensity changes can predict the degree of aneurysm volume reduction.
- This provides valuable insights into the natural history of treated aneurysms.
- Findings aid in predicting treatment outcomes and patient follow-up strategies.