Jean-Claude Dosch

Wrist Ligament Tears: Evaluation of MRI and Combined MDCT and MR Arthrography

OBJECTIVE The purpose of this study was to evaluate the performance of MRI and a combination of MDCT arthrography and MR arthrography in the diagnosis of tears and cartilage abnormalities of the wrist ligaments. SUBJECTS AND METHODS The feasibility of combining MDCT arthrography and MR arthrography and performing them with an optimized contrast solution was evaluated in vitro and in vivo. Forty-five consecutively enrolled subjects with suspected wrist ligament tears underwent MRI and a combined MDCT and MR arthrographic procedure. Two observers reviewed the images for evidence of tears and cartilage abnormalities of the scapholunate and lunotriquetral ligaments and triangular fibrocartilaginous complex. Interobserver agreement was determined with kappa statistics, and the diagnostic accuracy of each technique was calculated. RESULTS A 1:1 solution of 2.5 mmol/L tetraazacyclododecanetetraacetic acid (DOTA)-gadolinium and 300 mg I/mL iopamidol provided adequate contrast enhancement for both in vitro and in vivo MDCT arthrographic and MR arthrographic images. Interobserver agreement was substantial for MRI (kappa = 0.61) and MR arthrography (kappa = 0.71) and almost perfect for MDCT arthrography (kappa = 0.93). The sensitivity and specificity of MRI, MDCT arthrography, and MR arthrography for tears of the scapholunate ligament were 59% and 70%, 95% and 96%, and 68% and 87% for the first observer and 77% and 83%, 95% and 100%, and 77% and 87% for the second observer. For tears of the lunotriquetral ligament, these values were 30% and 94%, 100% and 94%, and 60% and 97% for the first observer and 50% and 97%, 90% and 100%, and 50% and 94% for the second observer. The three techniques appeared equivalent for complete tears of the scapholunate and lunotriquetral ligaments, but partial tears were significantly better visualized with MDCT arthrography. The sensitivity and specificity of MRI, MDCT arthrography, and MR arthrography for triangular fibrocartilaginous complex tears were 27% and 100%, 100% and 100%, and 82% and 100% for the first observer and 45% and 100%, 100% and 100%, and 82% and 100% for the second observer. For cartilage abnormalities, these values were 30% and 100%, 100% and 100%, and 30% and 100% for the first observer and 10% and 100%, 100% and 100%, and 40% and 100% for the second observer. CONCLUSION MDCT arthrography appears more accurate than MRI and MR arthrography, particularly for discerning partial tears of the scapholunate and lunotriquetral ligaments that do not necessitate surgical therapy.

Multidetector CT Arthrography of the Wrist Joint: How to Do It

With its exquisite spatial resolution, multidetector computed tomographic (CT) arthrography of the wrist is a valuable tool for the diagnosis and evaluation of a wide spectrum of articular disorders. Traumatic tears of the interosseous ligaments can be classified as complete or incomplete and as partial- or full-thickness tears at multidetector CT arthrography and can also be differentiated from asymptomatic degenerative lesions. In addition, tears of the triangular fibrocartilage complex can be differentiated according to their location. A tailored contrast material injection technique and multiplanar reformation are recommended for optimal assessment of these structures. Multidetector CT arthrography is also remarkably effective in demonstrating cartilage and bone abnormalities, many of which cannot be depicted with other imaging techniques. The chief limitation of multidetector CT arthrography lies in the evaluation of soft-tissue abnormalities, which may benefit from the addition of other imaging techniques such as ultrasonography or magnetic resonance imaging. A basic knowledge of the relevant anatomy, pathophysiologic features, and imaging technique is mandatory for obtaining high-yield diagnostic information concerning the wrist joint. (c) RSNA, 2008.

MDCT Arthrography or MR Arthrography for Imaging the Wrist Joint

Imaging of the wrist joint has been radically modified over the last decade, particularly since multidetector computed tomography (MDCT) arthrography and magnetic resonance (MR) arthrography have become widely available. These two modalities allow a confident assessment of ligament tears and potential diagnosis of associated abnormalities of cartilage, bone, and soft tissues. The interosseous scapholunate and lunotriquetral ligaments and the triangular fibrocartilage complex (TFCC) are the most important structures to consider. Precise analysis of their different lesions, including recognition of degenerative tears, is essential for guiding the treatment. After a brief overview of the different injuries of interosseous ligaments and cartilage, this article thoroughly exposes the technical aspects of wrist MDCT arthrography and MR arthrography, reviews their results, and discusses their performances in light of recent literature. Finally, we propose an imaging strategy to decide between MDCT arthrography and MR arthrography depending on the clinical query. Other imaging modalities are not forgotten in this strategy. The evaluation of ligamentous and TFCC pathology must always begin with conventional radiographs. Cineradiography, ultrasound, and standard MRI are also useful in selected cases.

Navigated non-image-based positioning of the acetabulum during total hip replacement

We tested the hypothesis that the non-image-based navigation system used in our department was able to measure accurately the 3D positioning of the acetabular cup of a total hip replacement (THR) and to increase the accuracy of its implantation during THR. We studied 50 consecutive navigated implantations of a THR and compared the intra-operative measurement of the cup by the navigation system to the post-operative measurement by computed tomography (CT) scan. The mean difference between the navigated and CT scan measurements for cup inclination was 2°. The mean difference between the navigated and CT-scan measurements for cup flexion was 4°. These differences were significant but considered to be clinically irrelevant in most cases. A total of 73% of the cases were within the safe zone defined prior to the study. The non-image-based system used allows a precise orientation of the cup during THR.RésuméLe but de notre étude est de mettre en évidence la possibilité de positionner de façon précise, dans les trois plans de l’espace, la cupule d’une prothèse totale de hanche et d’améliorer ainsi son implantation. Nous avons étudié 50 prothèses consécutives naviguées en comparant la mesure per opératoire de la cupule par le système de navigation et la mesure post opératoire par scanner. La différence entre les mesures faites par navigation et les mesures par scanner ne montre au niveau de l’inclinaison de la cupule qu’une différence de 2° et pour la flexion de 4°. Ces différences sont significatives mais n’ont aucune conséquence clinique dans la plupart des cas. 73% des cupules étaient dans la zone de sécurité que nous avions définie avant de mettre en route cette étude. En conclusion, le système de navigation sans image permet une orientation précise de la cupule lors d’une prothèse totale de hanche.

Intercostal myositis ossificans misdiagnosed as osteosarcoma in a 10-year-old child

Myositis ossificans (MO) is a rare benign cause of heterotopic bone formation within soft tissue. It most commonly affects adolescents and young adults, typically in the limbs and following trauma. Very few cases have been reported in children. We report here a case of nontraumatic MO occurring in a 10-year-old girl with an uncommon location in the 5th right intercostal space; it was initially misdiagnosed and treated as osteosarcoma. Imaging findings including plain radiographs, CT, MRI, bone scintigraphy and PET-CT are described. This case highlights the central role played by imaging in diagnosis, thus avoiding biopsy that can erroneously suggest osteosarcoma as the diagnosis, as occurred in this case.

Le bilan d'imagerie dans les traumatismes récents du rachis

Resume L’objectif de cette mise au point est de preciser la place actuelle des differentes modalites d’imagerie dans le bilan d’un traumatisme du rachis. Nous detaillons les differentes techniques disponibles en discutant leurs avantages et inconvenients respectifs, puis nous passons en revue le spectre des lesions observees, qu’elles soient osseuses, ligamentaires, vasculaires ou nerveuses. Enfin, nous proposons une strategie diagnostique integrant ces differents elements.