MRI of rupture of the spring ligament complex with talo-cuboid impaction.

The spring ligament complex is essential for the stability of the longitudinal arch of the foot and includes the ligaments between the calcaneus and the talus at the superomedial to inferoplantar aspect of the foot. Tears of the spring ligament complex are most commonly degenerative in etiology and secondary to concomitant abnormality of the posterior tibial tendon. We report MRI findings in a 30-year-old man who presented with traumatic rupture of the spring ligament complex, seen following dislocation of the talonavicular joint. We also describe the previously unreported MRI features of talo-cuboid impaction secondary to disruption of the spring ligament complex.

Use of a novel percutaneous biopsy localization device: initial musculoskeletal experience.

OBJECTIVE: To preliminarily evaluate a new CT-biopsy guidance device, the SeeStar (Radi, Uppsala, Sweden), for use in musculoskeletal applications. DESIGN: The device was evaluated using an imaging phantom and in various simulated clinical biopsy situations. The phantom study was undertaken to optimize the linear metallic artifacts produced by the guidance device. The phantom and guidance device were imaged with CT after altering different imaging parameters, including field of view, filter, focal spot size, kV, mAs, slice thickness and pitch. Clinical biopsy situations were simulated for a superficial biopsy, a deep biopsy and a horizontal biopsy approach. RESULTS: Altering CT parameters had little effect on the subjective appearance of the linear metal artifact, which is used to plan the biopsy approach. Placement of an 18-G needle inside of the biopsy device was subjectively helpful in exaggerating the artifact. Use of this artifact could be helpful in planning biopsy approach for deep lesions or lesions near critical structures. The metal guide on the device adequately supports a standard biopsy needle, making it potentially advantageous for biopsy of superficial lesions and lesions approached from a horizontal orientation. CONCLUSION: Use of this CT-biopsy guidance device is potentially useful for musculoskeletal applications. The linear metal artifact produced by the device can help plan the biopsy approach. The device can also be useful in biopsy situations where the biopsy needle requires external support during imaging.

MR imaging of thumb carpometacarpal joint ligament injuries.

This study describes the MR imaging appearances of the supporting ligaments of the thumb carpometacarpal joint in asymptomatic volunteers and in a group of patients following joint injury. Fourteen patients with 11 acute and three chronic injuries underwent MR imaging. The anterior oblique ligament was the most commonly injured ligament, usually on the metacarpal side where it was disrupted, or allowed dislocation because of subperiosted stripping from the base of the thumb metacarpal. The dorsal radial ligament was occasionally avulsed or partially torn from the trapezoid. Following chronic injury, MR imaging can evaluate ligamentous laxity, ganglion cyst formation or osteoarthritis. Accurate evaluation of ligament injury may identify patients who would benefit from surgery.

Radiochemistry: inconvenient but indispensable

Radiochemistry has always been and still is a crucial tool in the field of radionuclide determination, both for high and low level works; this holds particularly in the case of alpha and beta emitters. Requests to the analyst are increasingly demanding in terms of performance (detection limit, reliability, accuracy, precision,...), but also of economy (cost, time,...) and of flexibility with respect to sample types. In general, chemical and radiochemical analyses consist of four main steps: sample pre-treatment including pre-concentration, dissolution and/or digestion, separation of analytes from the matrix and from each other, transformation of the separated fraction into a source suited for measurement, determination of the amount or the activity of the analytes. The required combination of sub-procedures is determined by the analytes under investigation, their absolute and relative amounts, the matrix composition and by the performance required. IRMM's Analytical Chemistry Unit started several years ago to develop, adapt and/or validate various radiochemical methods and procedures, and apply these to different measurement tasks. This paper gives an overview on recent and ongoing activities.

Pre-concentration of actinoids from waters: a comparison of various sorbents

The first part of comparison study was based on the properties of different sorbents. These included different forms of manganese oxides, and specific organic ion-exchangers: HYPHAN and POLYORGS. In order to provide reproducible samples with moderate presence of possible interferences, spiked tap water was used for this first set of experiments. Results indicate that the sorption of Th, U, Pu and Am varies for different forms of manganese oxides. These variations are attributed to different physico-chemical properties of the oxides. HYPHAN was limited in its sorption to Th and U. The manganese oxide dissolved rapidly and the radiochemical separation procedure was quick and simple using extraction chromatography techniques. The radionuclides in the water samples were determined by ICP-MS and/or alpha spectrometry.