Introduction: The natural history of intracranial thrombosed aneurysm is unfavorable and treatment is difficult. Although the development of bypass and endovascular surgeries has improved results, some aneurysms grow larger and rupture. The mechanisms of growth remain unclear and some studies have reported the involvement of the vasa vasorum. We examined dynamic contrast-enhanced magnetic resonance imaging (MRI) to demonstrate the vasa vasorum of the aneurysm wall and evaluate relationships with the growth of intracranial thrombosed aneurysm.
Methods: Participants comprised 5 patients (4 men, 1 woman; mean age, 57.6±7.8 years) diagnosed with intracranial thrombosed aneurysm from December 2011 to November 2013 who were examined using dynamic contrast-enhanced MRI on more than two separate occasions. Two patients underwent bypass surgery, another 2 underwent endovascular surgery, and the remaining patient was treated conservatively. Dynamic MRI was performed using a 1.5-T system, and images were acquired from 15 s after injecting gadolinium-based contrast agent. Acquired images were analyzed and the transfer constant (Ktrans) was calculated. The region of interest was set in aneurysm thrombus.
Results: Three aneurysms grew larger and two decreased in size. Ktrans value of the aneurysm thrombus changed in proportion to aneurysm size. In linear regression analysis, the correlation coefficient between Ktrans and aneurysm size was 0.77.
Conclusions: In a dynamic contrast-enhanced study of intracranial thrombosed aneurysm, Ktrans of the thrombus correlates with changes in aneurysm size. Dynamic contrast-enhanced MRI is a valuable modality for predicting changes in thrombosed aneurysm size.
Patient Care: Our research will enable us to predict the change of aneurysm size and provide necessary surgical intervention.
Learning Objectives: By the conclusion of this session, participants should be able to describe the usefulness of dynamic contrast-enhanced MRI to evaluate thrombosed aneurysm.