Imaging of spinal intradural arachnoid cysts: MRI, myelography and CT.

Imaging studies in eight patients with surgically-confirmed spinal arachnoid cysts were analyzed retrospectively. All patients had preoperative MRI of the spine and seven preoperative myelography with postmyelographic CT. In all cases the correct diagnosis could be made preoperatively on the basis solely of MRI. The diagnosis could also be established from myelography and postmyelographic CT in six of the seven cases. In one case myelography and CT simply demonstrated an intradural extramedullary mass.

Visual pathway hemorrhage associated with alcohol-induced coagulopathy.

Hemorrhage confined to the optic pathways is rare. We describe a patient with diffuse hemorrhage of the intracranial optic nerves, optic chiasm, and optic tracts, attributed to alcohol-induced coagulopathy. The hemorrhage resolved completely as the patient's vision improved, and subsequent neuroimaging studies showed atrophy of the affected structures.

Assessing whether the plane of section on CT affects accuracy in demonstrating facial fractures in 3-D reconstruction when using a dried skull.

CT slice thickness and threshold value are well-known determinants of accuracy in three-dimensional (3-D) CT image reconstruction. The purpose of this study was to assess whether the plane selected for primary CT data acquisition, axial vs coronal, might also contribute to the accuracy and ease of identification of abnormalities in 3-D image reconstruction independent of the 3-D processing system used. Two sets of 10 observers evaluated fractures created in a dried skull and corresponding 3-D image data. A General Electric 9800 scanner was used to acquire the two-dimensional CT data. The 3D98 Quick software and ISG Camra Allegra workstation were used for two sets of 3-D reconstructions. The expected result was that fractures oriented perpendicularly to the initial plane of CT section would be better reconstructed on 3-D than when the initial plane of CT imaging paralleled the fracture. Our results indicate that Le Fort fractures (types I and III) are better displayed with coronal CT data and that zygomatic tripod fractures may be better displayed in 3-D with axial CT image data.

Preliminary clinical trial of gadodiamide injection: a new nonionic gadolinium contrast agent for MR imaging.

The safety and efficacy of a newly developed intravenous formulation of the nonionic contrast agent gadolinium diethylenetriaminepentaacetic acid-bis(methylamide), formulated as gadodiamide injection, was investigated. In 30 patients who underwent spin-echo magnetic resonance (MR) imaging before and after contrast agent enhancement, the enhanced images had characteristics judged similar to those of images enhanced by means of available gadolinium compounds. In 15 patients, contrast agent administration was of major diagnostic help, either revealing lesions not apparent without enhancement or providing important lesion characterization. In 12 patients, the lack of abnormal enhancement patterns was important in excluding the presence of disease. In three patients, the contrast agent did not provide information additional to that obtained with the unenhanced T1- and T2-weighted images. No clinically significant changes were observed in vital signs, neurologic status, or laboratory results. The authors conclude that, in this limited series, gadodiamide injection proved to be a safe and useful MR imaging contrast agent for evaluation of the central nervous system and surrounding structures.