Comparing T1-weighted and T2-weighted three-point Dixon technique with conventional T1-weighted fat-saturation and short-tau inversion recovery (STIR) techniques for the study of the lumbar spine in a short-bore MRI machine.

AIM: To compare T1-weighted (W) fat-water separation (Dixon's technique) with T1W fat-saturation (FS) and T2W Dixon with short-tau inversion recovery (STIR) images for fat suppression in a short-bore MRI machine. MATERIALS AND METHODS: Thirteen patients with lumbar disease were studied on using 1.5 T MRI machine. The protocol included T1 FS (with contrast medium administration) and/or STIR and T1W and/or T2W Dixon, for comparison. Three neuroradiologists scored the images from the two-pairs of techniques for fat suppression uniformity and lesion conspicuity. Clinical usefulness of fat-only images was also evaluated. RESULTS: Regarding uniformity of fat suppression, mean scores were 2.28 (±0.49), 3.06 (±0.49), 2.39 (±0.49), and 3.15 (±0.35) for T1W FS, T1W Dixon, STIR, and T2W Dixon sequences, respectively. For the same pulse sequences, lesion conspicuity scores were 2.78 (±0.50), 2.78 (±0.27), 2.76 (±0.47), and 2.91 (±0.4), respectively. Both T1W and T2W Dixon sequences showed more homogeneous fat-suppression when compared to T1W FS (p = 0.026) and STIR (p = 0.008) techniques, but no significant difference was found for lesion conspicuity. Mean scores for the diagnostic utility of fat-only maps were, respectively, 1.72 (±0.39) and 2.48 (±0.50) for T1W and T2W Dixon. CONCLUSION: Fat suppression quality was superior with Dixon when compared to the conventional sequences, but not lesion conspicuity, suggesting that both techniques are reliable for diagnosis. Dixon may be advantageous in cases where inhomogeneity artefacts are an issue. Water-only maps appear to be useful in the clinical setting.

Granulomatous infectious disease in an immunosuppressed patient: a case report with radiological and pathological correlation.

We report here on a case of disseminated aspergillosis in an immunocompromised patient with Wegener's granulomatosis to illustrate the complexity of brain imaging diagnosis in the presence of concomitant infectious, immunological and ischemic diseases.

Transient disabling dyskinesias: a predictor of good outcome in subthalamic nucleus deep brain stimulation in Parkinson's disease.

We report 5 of 75 (6.6%) patients with Parkinson's disease (PD) submitted to subthalamic nucleus deep brain stimulation (STN-DBS) who developed transient disabling dyskinesias immediately after surgery. Dyskinesias persisted despite levodopa withdrawal, cessation or reduction of stimulation, and resolved spontaneously in a maximum period of 12 weeks without the need to change stimulation active contact. Compared to the rest of our PD patients submitted to STN-DBS, the dyskinesia group needed a lower levodopa-equivalent daily dosage (LEDD) over the time of follow-up. A microlesion in the STN, probably concealed in cerebral MRI by the electrode-related artifact, could have been involved in the etiopathology of our patients' symptoms. The presence of transient disabling dyskinesia in PD patients immediately after STN-DBS might be a predictor of good outcome as measured by a decrease in the LEDD needed.

Agenesis of the internal carotid artery and hypogenesis of the pituitary gland: cause, consequence or coincidence?

The CT and MR imaging findings in a case of unilateral agenesis of the internal carotid artery and hypogenesis of the pituitary gland are described in a child with congenital hypopituitarism. The embryological pathogenesis is discussed.