MR Imaging of Orbital Inflammatory Pseudotumors with Extraorbital Extension

OBJECTIVE: To demonstrate a variety of MR imaging findings of orbital inflammatory pseudotumors with extraorbital extension. MATERIALS AND METHODS: We retrospectively reviewed the MR features of five patients, who were diagnosed clinically and radiologically as having an orbital inflammatory pseudotumor with extraorbital extension. RESULTS: The types of orbital pseudotumors were a mass in the orbital apex (n = 3), diffuse form (n = 2), and myositis (n = 1). The extraorbital extension of the orbital pseudotumor passed through the superior orbital fissure in all cases, through the inferior orbital fissure in two cases, and through the optic canal in one case. The orbital lesions extended into the following areas: the cavernous sinus (n = 4), the middle cranial fossa (n = 4), Meckel's cave (n = 2), the petrous apex (n = 2), the clivus (n = 2), the pterygopalatine fossa and infratemporal fossa (n = 2), the foramen rotundum (n = 1), the paranasal sinus (n = 1), and the infraorbital foramen (n = 1). On MR imaging, the lesions appeared as an isosignal intensity with gray matter on the T1-weighted images, as a low signal intensity on the T2-weighted images and showed a marked enhancement on the post-gadolinium-diethylene triamine pentaacetic acid (post-Gd-DTPA) T1-sequences. The symptoms of all of the patients improved when they were given high doses of steroids. Three of the five patients experienced a recurrence. CONCLUSION: MR imaging is useful for demonstrating the presence of a variety of extraorbital extensions of orbital inflammatory pseudotumors.

Perfusion MR Imaging of Cerebral Gliomas: Comparison with Histologic Tumor Grade

PURPOSE: Our purpose was to compare maximum relative cerebral blood volume (rCBV) with histologic grade of cerebral gliomas. MATERIALS AND METHODS: First-pass perfusion MR imaging was performed preoperatively in 16 patients with pathologically proven cerebral gliomas (7 glioblastoma, 2 anaplastic astrocytoma, 1 anaplastic oligo-dendroglioma, 5 low-grade astrocytoma, and 1 low-grade oligodendroglioma). Maximum rCBV was com-pared with histologic diagnosis and grade of the tumor. RESULTS: Maximum rCBVs of glioblastomas were in the range of 433%-1330% (average, 790%), as compared with those of contra-lateral normal white matters. Maximum rCBVs of two non-enhancing anaplastic astrocytomas were 66% and 284%, respectively. Maximum rCBV of one well-enhancing anaplastic oligodendroglioma was 502%. Maximum rCBVs of low-grade astrocytomas were in the range of 80%-369% (average, 202%). Maximum rCBV of one low-grade oligodendroglioma was 1450%, even higher than those of glioblastomas. CONCLUSION: Maximum rCBV was higher in glioblastoma than in low-grade astrocytoma without overlap-ping. However, there was no difference of maximum rCBV between non-enhancing anaplastic astrocytoma and low-grade astrocftoma.