A compact MRI system for measuring the trabecular bone (TB) microstructure of the finger using a high-field-strength (1.0T) permanent magnet was developed. The entire system was installed in a 0.6 m ؋ 1.2 m space. One male and 36 female subjects participated in the imaging experiments. The TB of the distal phalanx of the middle finger was imaged at a voxel resolution of (160 m) 3 using a three-dimensional (3D) driven equilibrium spin-echo (SE) imaging sequence (imaging time ‫؍‬ ϳ14 min). The image data sets obtained yielded two distinct peaks for the bone and marrow in image intensity histograms when no motion was present. The structural parameters obtained through 3D image analysis show that this compact system is potentially useful for evaluating bone quality. Magn Reson Med 57:272-277, 2007.

Purpose: To investigate the feasibility of an originally developed compact MRI system for evaluating rheumatoid arthritis (RA), and determine its advantages and disadvantages as an imaging modality for evaluating RA. Materials and Methods:We prospectively studied 13 healthy controls with no clinical symptoms of arthritis, and 13 patients with hand and wrist pains (including pain from RA) with a 0.2 T permanent-magnet compact MR imager. All MR images were obtained while the subjects were in a sitting position. Coronal three-dimensional spin-echo T1-weighted images and coronal two-dimensional short tau inversion recovery (STIR) images were obtained with image matrix ϭ 256 ϫ 128 and field of view (FOV) ϭ 20.48 cm. Plain radiograph findings and MRI findings of patients were compared.

A compact MRI system for trabecular bone (TB) microstructure measurements of the distal radius was developed using a 1.0 T permanent magnet and a compact MRI console. TB microstructure of the distal radius was clearly visualized using a threedimensional (3D) driven equilibrium spin-echo (

We repeatedly measured the trabecular bone (TB) microstructure of the distal radius in 5 healthy volunteers using a compact magnetic resonance (MR) imaging system to evaluate the reproducibility of the TB structural parameters. The compact system was specially developed with a 1.0-tesla permanent magnet for the distal radius in a previous study. We measured the distal radius using a 3-dimensional (3D), driven-equilibrium, spin-echo sequence (repetition time/echo time＝80 ms/10 ms, number of excitations＝1,ˆeld of view ＝76.8 mm×57.6 mm×16.0 mm, acquisition time＝17 min, matrix size＝512×384×32, voxel size＝150 mm×150 mm×500 mm) and analyzed the acquired image datasets using the virtual bone biopsy system developed by the University of Pennsylvania. Root mean squares of the coe‹cients of variance expressed as percentages ranged from 2.9z to 14z for the TB structural parameters. Therefore, we concluded that this compact MR imaging system could be used to assess TB microstructure of the distal radius and provide results consistent with those using a whole-body MR imaging system and showing the promise of this system for evaluating bone quality in clinical settings.

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