Traumatic brachiocephalic pseudoaneurysm presenting with delayed stroke: case report.

We report a traumatic pseudoaneurysm of the internal carotid artery bifurcation and subclavian artery with recurrent strokes events in a 19-year-old man. He was admitted with an acute left hemiparesis. His history revealed a similar episode 1 year and a major car accident 3 years previously. Contrast enhanced MR angiography confirmed colour Doppler sonographic findings of a carotid and subclavian artery pseudoaneurysm presumably resulting from seat-belt trauma. The pseudoaneurysm, containing thrombus, was thought to be the source of artery-to-artery embolism.

MRI with superparamagnetic iron oxide: efficacy in the detection and characterization of focal hepatic lesions.

The purpose of this study was to evaluate the potential of superparamagnetic iron oxide particles (SPIO) as tissue specific contrast agent in magnetic resonance (MR) imaging in detection and characterization of focal hepatic lesions. We investigated 45 patients with focal hepatic lesions. T1-weighted SE (TR 650/TE 15 ms) and T2-weighted SE (TR 2015-2030/TE 45 and 90 ms) unenhanced images were obtained. After SPIO application we performed T1-weighted images with and T2-weighted images with and without fat suppression using the same image parameters. Liver signal intensity decreased by 74% (min 47%, max 83%) on T2-weighted images after application of the contrast agent. Benign lesions (FNH, adenoma) showed an average signal drop of 40% (min 20%, max 47%) whereas malignant lesions showed no significant change of signal intensity on post-contrast images. The mean tumor-to-liver contrast-to-noise ratio (C/N) was improved in all post-contrast sequences irrespective of the lesion type. An additional increase of tumor-to-liver contrast by use of fat suppression technique could be established in the slightly T2-weighted sequence (TE 45 ms). In metastases, divided in different size groups, we could determine a significant size relation of tumor-to-liver C/N. After SPIO application the number of detected lesions increased distinctly, especially small foci are more easily demonstrated. SPIO particles are a efficacious contrast agent for MR examinations of the liver. For tumor characterization T1- and T2-weighted pre- and post-contrast images are necessary. The T1-weighted sequences are helpful to differentiate benign lesions such as cysts and hemangiomas from malignant lesions. Detection and differential diagnoses of hepatic lesions are improved by use of the SPIO-particles.

Isolated oculomotor nerve paralysis in Lyme disease: MRI.

Lyme disease is a cause of illness involving multiple organ systems, including, in 10-15 % of cases, the nervous system. Peripheral radiculoneuritis, cranial neuritis, encephalitis and myelitis are among the neurological manifestations found in the second and third stages. We present the MRI findings in isolated oculomotor nerve involvement by Lyme disease and discuss the differential diagnosis.