Sandra W. Horowitz

Complex partial seizure-induced transient MR enhancement.

A 58-year-old man with complex partial seizures had transient symmetrical MR enhancement in the anterior mesiotemporal cortex bilaterally, correlated with the sites of seizure focus on electroencephalography. Preinfused T1-weighted and T2-weighted sequences showed no abnormality. After adequate control of seizures with medication, repeat MR was normal and the prior enhancement was no longer seen. This transient seizure-induced MR enhancement was consistent with ictal or postictal hyperemia and breakdown of the blood-brain barrier and should not be erroneously attributed to mesial temporal sclerosis, encephalitis, tumor, or infarction.

Agenesis of corpus callosum and intraventricular lipomas

Intracranial lipomas are rare and usually do not have clinical expression. They are located most commonly in the interhemispheric fissure and may also be found in the quadrigeminal, ambient, chiasmatic, interpeduncular, sylvian, and perimesencephalic cisterns. Interhemispheric lipomas may be associated with choroid plexus lipomas. The ultrasonography, computed tomography, and magnetic resonance imaging findings are reported in a neonate with lateral ventricular choroid plexus lipomas and interhemispheric lipoma associated with agenesis of the corpus callosum.

Differentiation of benign versus metastatic vertebral body compression fractures

Six patients with benign fractures showed a sharply demarcated vertical band of preserved bone marrow along the dorsal one-third of the compressed vertebral body, while the anterior two-thirds showed decreased signal intensity (SI) with a T1-weighted sequence. This “posterior band sign” seen in benign, and not seen in metastatic, fractures correlates well with the biochemical theory of the “three column spine”. The latter defines compression fracture by an intact “middle column” which includes the dorsal one-third of the vertebral body, posterior annulus fibrosus, and posterior longitudinal ligament. Metastatic fractures showed either complete or irregular bone marrow replacement of multiple vertebral bodies and of posterior elements. Other benign patterns included a horizontal band of low SI adjacent to the superior or inferior vertebral endplate, isointense or increased SI of the vertebral body in images with a T1-weighted sequence. Two fractures were indeterminate.

Recurrent disc herniation versus scar: triple- versus single-dose gadoteridol

We carried out MRI to evaluate possible recurrent herniated nucleus pulposus (HNP) before and after i.v. infusion of 0.1 mmol/kg gadoteridol, immediately followed by an additional 0.2 mmol/kg and repeat imaging in 21 patients. In comparison with standard 0.1 mmol/ kg gadoteridol, images at a cumulative 0.3 mmol/kg demonstrated increased epidural enhancement, increased enhancement of intradural and affected S1 nerve roots. The level of certainty in MRI diagnosis of recurrent HNP at 0.3 mmol/kg was decreased in 5, increased in 1, and unchanged in 4 patients compared with standard dose. The triple dose was not advantageous for identification of recurrent HNP, owing to the increased peridiscal and S1 nerve root enhancement, which masked the displaced S1 nerve root and decreased the conspicuity of HNP.

Contrast medium extravasation during embolization of intracranial arteriovenous malformation without associated intracranial hematoma

We describe the radiographic findings in two patients who underwent intracranial embolization for arteriovenous malformation in whom, during the course of the embolization, extravasation of contrast medium without concomitant hemorrhage was identified on subsequent angiography and confirmed surgically.