Nontraumatic spinal epidural hematomas: MR features

Nontraumatic spinal epidural hematomas: MR features

380 CLINICAL IMAGING VOL. 21, NO. 5 ABSTRACTS and occluded (100%). The agreement of SD-CT angiography with intraarterial digital subtraction angiog...

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and occluded (100%). The agreement of SD-CT angiography with intraarterial digital subtraction angiography (DSA) was 62% (r = 0.89; p < 0.0001) and of duplex sonography with DSA was 77% (r = 0.94; p < 0.0001). Both modalities underestimated one occlusion as stenosed. In the evaluation of moderate and severe stenoses 3D-CT angiography showed an agreement with DSA in 50% (duplex: 88%) and 55% (duplex: 89%) respectively and was inferior to duplex sonography. In conclusion, 3D-CT angiography is inferior to duplex sonography in the evaluation of carotid stenosis and is not useful as a screening or reference examination. Authors’ Summary

THREE-DIMENSIONAL MAGNETIZATIONPREPARED TIME-OF-FLIGHT MR ANGIOGRAI’IIY OF THE CAROTID AND VERTEBRAL ARTERIES Wilman AH, Huston J III, Riederer SJ (S.J.R.: Research Laboratory, Mayo Clinic, 200 First Street, SW, Rochester, MN 55905). Magn Reson Med 1997;37:252-259, Three-dimensional magnetization-prepared (MP) magnetic resonance angiography (MRA) was applied to the carotid and vertebral arteries by using ECG triggering, a slab selective RF inversion pulse, centric phase encoding, and acquisition during diastole. Both theoretically and experimentally, the MP MRA sequence was shown to perform well in cases where there was substantial blood replenishment during the inversion time Tl (>330 ms). In comparison with standard, ungated, steady-state 3D time-of-flight MRA in 13 consecutive volunteers, the MP MRA images demonstrated better background suppression with less artifact and generally had more uniform vessel depiction. The MP MRA sequence was generally superior for portraying vessels exhibiting high pulsatility such as the carotid siphon. However, in distal vessels with slow flow and incomplete blood replenishment, the MP MRA technique was inferior due to increased loss of vessel signal. The reasons for this increased signal loss are identified and improvements to the MP MRA sequence are suggested. Authors’ Summary


Lovblad K-O, Baumgartner RW, Zambaz B-D, et al. (MRl Unit, Radiology Department, Harvard Medical School, Beth Israel Hospital AN 234, 330 Brookline Avenue, Boston MA 02215). Acta Radio1 1997;38:8-13. Spinal epidural hematoma (SEH) is a rare clinical entity with a bleak outcome. The aim of our study was to establish the value of magnetic resonance (MR) findings in the diagnosis of nontraumatic SEH. Seven patients with nontraumatic SEH were examined by MR at 1.5 T. Two patients were under anticoagulation therapy with heparin, and two others were taking salicylic acid. One patient had lupus erythematodes with a marked thrombocytopenia. One patient had a spinal arteriovenous malformation. MR imaging permitted the accurate localization of extradural intraspinal expansive lesions which exhibited the characteristic signal intensities of blood. Five patients underwent laminectomy and evacuation of the hematoma. In the acute phase, the hematomas appeared isointense when compared with the spinal cord on Tl-weighted images and hyperintense on T2weighted images. Later the hematomas were hyperintense on Tl-weighted images and showed signals identical to those of cerebrospinal fluid (CSF) on T&weighted images. MR imaging established the exact diagnosis and localization of SEH in all cases. MR can also provide useful information about the age of the hematomas. Authors’ Summary

NEURO-ENDOSCOPIC THIRD VENTIUCULOSTOMY: EVALUATION WITH MAGNETIC RESONANCE IMAGING Wilcock DJ, Jaspan T, Worthington BS, Punt J (University Department of Radiology, Leicester Royal Infirmary, Leicester LEl 5WK, UK). Clin Radio1 1997;52:50-54. This is a retrospective review of the data obtained on 14 patients who underwent magnetic resonance (MR) imaging prior to neuro-endoscopic third ventriculostomy. Serial MR studies were performed after the surgical procedure. MR imaging proved to be invaluable in the planning of the surgical procedure, providing important data on the endoscopic approach and in the follow-up. Antonio F. Govoni, MD