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Objective: To assess the multirater agreement of the modified Outerbridge system for the grading of predefined areas of femorotibial cartilage at CT arthrography with multiple readers, with varying experience., Design: Five readers with varying experience (two junior radiologists, three musculoskeletal radiologists including two experts in cartilage imaging) separately analyzed 962 cartilage sectors from pre-divided knee CT arthrograms with femorotibial osteoarthritis (Kellgren/Lawrence=3). Each cartilage area was graded twice by each reader, at a three-month interval, according to the modified 5-grade Outerbridge system. Interobserver and intraobserver agreement were assessed. After the second reading, 121 areas exhibiting the highest interobserver disagreement were reviewed in consensus to determine the sources of disagreement., Results: The global interobserver agreement was fair (k=0.35), and increased with the grade (from k=0.14 to k=0.76 from grade 0-4). The intraobserver agreement varied with the readers' experience from moderate (k=0.59) to almost perfect (k=0.92). The majority of cases of disagreement (44%) was due to difficulties in assessing the normal variations of cartilage thickness, including diffuse cartilage thinning (23%) and normal variants of cartilage thickness (22%). 32% of cases of disagreement were due to retrospectively avoidable interpretation errors., Conclusions: The multirater agreement of the modified Outerbridge system is only fair when readers of different level of experience are taken into account, and interobserver agreement increases with readers' experience. However, interobserver agreement is substantial for grade 4 lesions. We report normal variations of cartilage thickness that may improve observer agreement in reporting cartilage lesions., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To compare an automated scan planning method to manual scan positioning in routine knee magnetic resonance imaging (MRI) studies., Materials and Methods: The automated scan planning method uses anatomical landmarks in a 3D survey of the knee. The method is trained by example plannings, consisting of manual slice positioning by an experienced technologist in 15 MRI studies. Automated knee MR examinations obtained in three geometries in 50 consecutive patients were compared to those obtained in 50 consecutive control patients, where imaging planes were planned manually. Anatomical coverage and slice angulation were scored for each geometry on a 4-grade scale by an experienced radiologist blinded to the way of planning; groups were compared using a Mann-Whitney U-test., Results: In 150 automated sequences the technologist adapted slice positioning in four cases (addition of slices to adapt to the size of the knee), representing the only automated sequences that received a poor rating. Thirteen sequences with manual planning received a poor rating. No difference in quality was found (P > 0.05) between automated and manual plannings for coronal coverage, sagittal coverage and angulation, and transverse angulation. Rating of automated planning was higher for transverse coverage, but lower than manual planning for coronal angulation., Conclusion: Automated sequence prescription for knee MRI is feasible in clinical practice, with similar quality as manual positioning.

This article focuses on spontaneous painful conditions involving the subchondral bone and marrow of mature knee epiphyses. MR imaging is the technique of choice for the work-up of these lesions and enables distinction of two main categories of lesions on the basis of T1-weighted images: avascular necrosis, and lesions presenting the bone marrow edema pattern. This latter category encompasses spontaneous osteonecrosis of the knee, and a variety of self-resolving conditions that may be differentiated by the study of the subchondral bone marrow area on T2-weighted images. Behind definite appellation of lesions, the challenge for the radiologist is to provide a prognosis: the distinction between self-resolving lesions from those that may evolve to epiphyseal collapse and joint impairment should be possible in most cases.

Purpose: To assess the effectiveness of dual-detector row spiral computed tomographic (CT) arthrography of the knee in the evaluation of the postoperative meniscus for recurrent or residual meniscal tear., Materials and Methods: Spiral CT arthrography was performed in 20 patients who presented with pain after partial meniscectomy. Findings at the initial reading of the images and at two retrospective independent readings were compared with those at second-look arthroscopy performed in all patients. At initial interpretation, conventional criteria for meniscal tear were used, including partial- or full-thickness tear of any size and meniscal separation. At retrospective interpretation, criteria for meniscal tear included large partial- and full-thickness tear and meniscal separation but not small partial-thickness tear. Sensitivity and specificity for the detection of tear of the postoperative menisci were calculated for initial and retrospective readings., Results: At initial interpretation, the sensitivity and specificity for the detection of tear of the postoperative menisci were 100% and 78%, respectively. At retrospective interpretation, the sensitivity and specificity for the detection of tear of the postoperative menisci were 79% and 89% at reading 1 and 93% and 89% at reading 2, respectively., Conclusion: Spiral CT arthrography is valuable for the assessment of postoperative menisci, but the application of conventional definitions of meniscal tear to arthrographic findings in postoperative menisci can lead to overestimation of the clinical importance of meniscal lesions.

Objective: To determine the frequency and topography of cartilage lesions involving the femoro-tibial joints in patients with normal knee radiographs and without a remembered history of trauma., Design and Patients: A radiologist retrospectively reviewed the dual-detector spiral CT knee arthrograms performed in 209 consecutive patients (mean age 37.6 years) with normal knee radiographs. Images were analyzed for the presence, grade (Noyes classification system) and location of cartilage lesions, the location being designated by dividing each articular surface into a grid of 16 parts., Results: Fifty-three percent of knees had cartilage lesions of grade 2A or higher that involved articular surfaces to a variable extent: lateral tibial plateau (31%), medial femoral condyle (27%), medial tibial plateau (14%) and lateral femoral condyle (5%). Areas of the posterior half of the lateral tibial plateau and of the inner half of the medial femoral condyle were statistically more frequently involved than their counterparts (P<0.0001). The bare area of the medial tibial plateau, but not that of the lateral tibial plateau, was more frequently involved than the corresponding meniscus-covered area (P<0.0001)., Conclusion: Cartilage lesions of grade 2A or higher, detected at spiral CT arthrography in 53% of the knees, predominantly involved the posterior half of the lateral tibial plateau, the inner half of the medial femoral condyle and the bare area of the medial tibial plateau.

Computed tomography imaging has achieved excellent multiplanar capability and submillimeter spatial resolution due to the development of the spiral acquisition mode and multidetector row technology. Multidetector spiral CT arthrography (CTA) yields valuable information for the assessment of internal derangement of the joints. This article focuses on the value of spiral CTA of the knee in the assessment of the meniscus, anterior cruciate ligament, and hyaline cartilage lesions. Advantages and disadvantages of spiral CTA with respect to MR imaging are presented.

Computed tomography (CT) has gained multiplanar capability and submillimeter spatial resolution due to the development of spiral acquisition mode and multidetector row technology. Multidetector spiral CT arthrography of the knee is a valuable imaging modality for the assessment of lesions of the meniscus, anterior cruciate ligament (ACL), and articular cartilage. This article presents the value of spiral CT arthrography in the assessment of the postoperative knee with emphasis on the postoperative meniscus, articular cartilage, and ACL graft. This technique may be proposed as an alternative to magnetic resonance arthrography.

Purpose: To assess dual-detector spiral CT arthrography in the evaluation of the entire knee cartilage obtained from cadavers., Materials and Methods: Two independent observers characterized articular cartilage in 12 cadaver knees in which MR imaging and dual-detector spiral CT arthrography were performed and compared their findings to those found during macroscopic assessment. The sensitivity and specificity of MR imaging and spiral CT arthrography for detecting grade 2A or higher and grade 2B or higher cartilage lesions, the Spearman correlation coefficient between arthrographic and macroscopic grading, and kappa statistics for assessing interobserver reproducibility were determined., Results: At spiral CT arthrography, sensitivities and specificities ranged between 80% and 88% for the detection of grade 2A or higher cartilage lesions and ranged between 85% and 94% for the detection of grade 2B or higher cartilage lesions. At MR imaging, sensitivities and specificities ranged between 78% and 86% and between 76% and 91% for the detection of grade 2A or higher and grade 2B or higher cartilage lesions, respectively. Spearman correlation coefficients between spiral CT arthrography or MR imaging and macroscopic grading of articular surfaces were 0.797 and 0.702, respectively., Conclusion: Dual-detector spiral CT arthrography of the knee is a valuable method for the assessment of open cartilage lesions of the entire knee.

Objective: The diagnosis of ganglion cysts of articular origin may sometimes be uncertain when communication with the joint is not evident. Because we have observed that opacification of ganglion cysts revealed by arthrography can be significantly delayed, the purpose of this study was to determine retrospectively in 20 cases the time delay needed to show with arthrography a communication between the articular cavity and ganglion cysts of the knee., Conclusion: Arthrographic evidence of a communication between the articular cavity of the knee and communicating ganglion cysts requires delayed radiography performed at least 1 hr after intraarticular injection of contrast material. The best results are obtained with additional CT performed 1-2 hr after injection.