The Norwich Osteoarthritis of the Ankle MRI Score (NOAMS): a reliability study.

AIM: To define and test the inter- and intra-rater reliability of a grading system for staging osteoarthritis (OA) of the ankle with magnetic resonance imaging (MRI) (Norwich Osteoarthritis of the Ankle MRI Score, NOAMS). MATERIALS AND METHODS: The MRI features to be included in the score were defined by a multidisciplinary expert panel through a Delphi process. An anonymised randomised dataset of 50 MRI studies was created from patients with concurrent plain radiographs to include 10 ankles of each of the Kellgren-Lawrence grades 0 to 4. Two experienced musculoskeletal radiologists and two trainees scored each ankle MRI twice independently and blinded to the plain radiographs. RESULTS: The inter-rater kappa coefficient of agreement for cartilage disease was 0.88 (95% confidence interval [CI]: 0.85, 0.91) for experienced raters and 0.71 (95% CI: 0.67, 0.76) for trainees. Inter-rater agreement for subchondral bone marrow oedema and cysts varied from 0.73 to 0.82 for experienced raters and from 0.63 to 0.75 for trainees with lowest 95% CI of 0.48 and 0.63. When bone marrow lesions were combined into a total joint score the level of agreement increased to between 0.88 and 0.97 with lowest 95% CI of 0.86. Combining cartilage zone scores did not increase the reliability coefficients. CONCLUSION: An expert panel considered that cartilage degradation and subchondral bone marrow lesions were the most important features for staging the severity of ankle OA on MRI. Experienced observers can grade the severity of ankle OA on MRI with a clinically useful high degree of reproducibility.

Multislice CT of the abdomen.

Major advances have been made in CT technology since its introduction 30 years ago. Examination time has been markedly reduced and it is possible to cover considerably larger scan ranges. Multidetector technology now allows near isotopic imaging with the ability to perform high quality multiplanar reconstructions. It is also now possible to image in well defined vascular phases. In this article we share our experience in the use of multislice CT and detail protocols used in imaging of the abdomen.

CT and MRI of hip arthroplasty.

Plain films are the initial imaging method of choice for evaluation of hip arthroplasty. Recent advances in technology and imaging techniques have largely overcome the problems of beam hardening in computed tomography (CT) and magnetic susceptibility artefact in magnetic resonance imaging (MRI). CT and MRI have now become useful imaging techniques in the assessment of hip arthroplasty.