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[Usefulness of selective partial inversion recover (SPIR) sequences in optic nerve diseases]
A Pierallini1, M C Piattella, N S Polli
1Dipartimento di Scienze Neurologiche, Università La Sapienza, Roma. pierallini@AXRMA.UNIROMA1.IT
Purpose:
To evaluate the yield of SPIR sequences with fat suppression in the diagnosis of optic nerve lesions.
Material And Methods:
Ten patients with suspected optic nerve involvement on the basis of clinical data and abnormalities of visual evoked potentials were examined. MRI was performed with a 1.5 T unit (Philips NT 15) using T1 weighted conventional spin-echo and T1- and T2 weighted SPIR sequences with fat suppression. Axial images were obtained along the optic nerve course, while coronal images throughout the optic nerve axis; slices were 3 mm thick. Axial T2 weighted SPIR sequences were also performed with the volumetric technique (1.5 mm thickness); coronal and parasagittal reconstructions along the nerve axis were obtained too. After paramagnetic contrast medium injection, conventional T1 weighted and SPIR sequences were performed on axial and coronal planes.
Results:
Optic nerve lesions consistent with the diagnosis of neuritis were demonstrated with T2 weighted images in 4 of 10 patients. No abnormalities and/or nerve enlargement were found on T1 weighted images. An enhancement area was seen after contrast medium injection in only one case. MRI showed a pilocytic astrocytoma in one patient and selective atrophy of the right optic nerve in another. MRI showed normal findings in 4 patients.
Conclusions:
T1 and T2 weighted fat-suppressed SPIR imaging of the optic nerve improves anatomical definition, lesion detection and characterization in optic nerve conditions.