The likelihood of rupture of unruptured intracranial aneurysms that were less than 10 mm in diameter was exceedingly low among patients in group 1 and was substantially higher among those in group 2. The risk of morbidity and mortality related to surgery greatly exceeded the 7.5-year risk of rupture among patients in group 1 with unruptured intracranial aneurysms smaller than 10 mm in diameter.

General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. AbstractObjectice: To evaluate the magnetic resonance imaging (MRI) findings of 15 patients with perineural tumor extension along the trigeminal nerve in correlation with clinical data. ,~Iethods: The clinical records and MRI studies of 15 patients with perineura.l tumor extension along the trigeminal nerve were retrospectively reviewed. Imaging studies included plain and contrast-enhanced thin section Tl-weighted spin echo (T1-WSE) MRI with and without fat-suppression. The studies were compared to determine which sequence provided greatest tumor conspicuity and best depiction of tumor extent. The conspicuity of these tumors was assessed on the available sequences by two observers by consensus. Results: The contrast-enhanced Tl-weighted spin echo fat-suppressed images (TI-WSECEFS) demonstrated greatest tumor conspicuity and best depiction of tumor extent in the extracranial head and neck and skull base region. The conventional Tl-weighted spin echo pre-and postcontrast images were, however, diagnostic of perineural tumor extension in 11 patients due to the presence of considerable tumor bulk and extension well above the skull base. In the other four patients the perineural tumor was poorly visualized on the conventional TI-WSE images and well visualized on the fat-suppressed images. The mandibular division of the trigeminal nerve (V3) was most commonly involved (n = 10), followed by the maxillary. (V2; n = 5) and ophthalmic (VI; n = 2) division. Two patients had both mandibular as well as maxillary nerve involvement. The finding of perineural tumor extension had significant impact on patient management: based on the MR imaging study, the primary tumor was considered inoperable (n = 13), the extent of surgery was expanded (n = 2) and radiation therapy (RT) ports were extended (n = 12). Conclusion: Complete trigeminal nerve imaging is recommended when evaluating (suspected) head and neck malignancies with a high risk for perineural extension. In these cases thin section axial and coronal precontrast T1-WSE MR images and postcontrast TI-WSE MR images with fat-suppression should be obtained. In the rare event that artifacts degrade the quality of the fat-suppressed images, contrast-enhanced TI-WSE sequences without fat...

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