Cartilage quantification using contrast-enhanced MRI in the wrist of rheumatoid arthritis: cartilage loss is associated with bone marrow edema.

OBJECTIVE: To quantify wrist cartilage using contrast MRI and compare with the extent of adjacent synovitis and bone marrow edema (BME) in patients with rheumatoid arthritis (RA). METHODS: 18 patients with RA underwent post-contrast fat-suppressed T1weighted coronal imaging. Cartilage area at the centre of the scaphoid-capitate and radius-scaphoid joints was measured by in-house developed software. We defined cartilage as the pixels with signal intensity between two thresholds (lower: 0.4, 0.5 and 0.6 times the muscle signal, upper: 0.9, 1.0, 1.1, 1.2 and 1.3 times the muscle signal). We investigated the association of cartilage loss with synovitis and BME score derived from RA MRI scoring system. RESULTS: Cartilage area was correlated with BME score when thresholds were adequately set with lower threshold at 0.6 times the muscle signal and upper threshold at 1.2 times the muscle signal for both SC (rs=-0.469, p < 0.05) and RS (rs=-0.486, p < 0.05) joints, while it showed no significant correlation with synovitis score at any thresholds. CONCLUSION: Our software can accurately quantify cartilage in the wrist and BME associated with cartilage loss in patients with RA. Advances in knowledge: Our software can quantify cartilage using conventional MR images of the wrist. BME is associated with cartilage loss in RA patients.

[Cerebellum and eye movement control -- neuronal mechanisms of memory-based smooth-pursuit and their early clinical application].

Recent studies implicate the cerebellum in cognitive functions in addition to its well-established roles in motor control and learning. Using a memory-based smooth-pursuit task that separates visual working memory from motor preparation and execution, monkeys were trained to pursue (i.e., go) or not pursue (i.e., no-go), a cued direction, based on the working memory of visual motion-direction and a go/no-go instruction. Task-related neuronal activity was examined in cerebral and cerebellar major smooth-pursuit pathways. Different cerebral and cerebellar areas carried distinctly different signals during memory-based smooth-pursuit. In the cerebellum, prediction-related signals (visual working memory, pursuit selection and movement preparation) were represented in the vermal lobules VI-VII and caudal fastigial nucleus, whereas the floccular region (flocculus and ventral paraflocculus) contained predominantly execution-related signals. This task was applied to patients with cerebellar degeneration and idiopathic Parkinson's disease (PD). None of the PD patients tested exhibited impaired working memory of motion-direction and/or go/no-go selection, but they did show task-specific difficulty in generating an initial smooth-pursuit component, suggesting difficulty in smooth-pursuit preparation. In contrast, most cerebellar patients exhibited impaired visual working memory in addition to difficulty in preparing for and executing smooth-pursuit. These results suggest different roles for the basal ganglia and cerebellum in smooth-pursuit planning.

[Three-dimensional imaging of the optic nerve using magnetic resonance angiography--application to anterior communicating artery aneurysm and craniopharingioma].

The purpose of this investigation was to analyze three-dimensional images of the optic nerve obtained by magnetic resonance angiography (MRA) in cases of anterior communicating artery aneurysm and craniopharingioma. Four ruptured anterior communicating artery aneurysms, five non-ruptured anterior communicating artery aneurysms and two craniopharingiomas were examined. The images were taken using MR/i Hispeed Plus 1.5T Infinity version, and analyzed by Advantage Work station AW4.1. The routine MR imaging parameters are shown in Table. The imaging time was about 10 minutes. Analysis was made by reformation of images parallel to the optic nerve obtained from the original MRA images. The optic nerve and brain tumor were traced with paintbrush from one sheet to another of the reformed images after subtraction of the blood vessels around the anterior communicating artery in these reformed images, and then three-dimensional images were constructed. Three-dimensional images of the blood vessels were reconstructed from MIP (maximum intensity projection) images using the threshold method. The optic nerve and anterior communicating arterial aneurysm or brain tumor were both observed in the overlapped 3D-SSD (shaded surface display) images. The analysis time was about 15 minutes. Three-dimensional images of the optic nerve and anterior communicating artery aneurysm or brain tumor were able to be made in all cases. As a preoperative investigation for anterior communicating artery aneurysm or suprasellar brain tumor, we considered that three-dimensional imaging of the optic nerve is useful in the operative approach because the optic nerve acts as a merkmal for the anterior communicating aneurysm or brain tumor.