Riccardo Lattanzi PHD, Presenter: Nothing to Disclose

Catherine Niyada Petchprapa MD, Abstract Co-Author: Nothing to Disclose

Daniele Ascani, Abstract Co-Author: Nothing to Disclose

Michael Paul Recht MD, Abstract Co-Author: Nothing to Disclose

To assess the performance of dGEMRIC in predicting hip cartilage damage in a retrospective analysis of patients with femoroacetabular impingement (FAI). Our hypothesis was that standardized dGEMRIC maps, where the effects of patient’s age, sex and diffusion of gadolinium contrast are removed, are more effective than morphologic evaluation.

This study had institutional review board approval. We evaluated retrospectively 19 hips in 19 FAI patients (34 ± 11y, 9 males) who underwent preoperative dGEMRIC at 3 Tesla (T) and hip arthroscopy (52 ± 34 days after MRI) at our institution. dGEMRIC maps were acquired along radial imaging planes and transformed in standard scores (z) maps using an internal reference corresponding to healthy cartilage. A total of 82 radial sections (at least 2 per patient) were used in this study. We assessed the anterior-superior and posterior-superior regions of the hip acetabular cartilage using z = -2 (i.e. 2 stdev) as the threshold between normal and damaged cartilage. Inter and intra-observer variability were established for the dGEMRIC analysis. Morphologic evaluation was performed using high-resolution PD-weighted 3 T MR images, acquired along the same radial planes. Sensitivity, specificity, accuracy, positive and negative predictive value (PPV and NPV) were assessed based on the arthroscopic findings.

All patients had either torn or detached labrum. 16 patients had FAI (2 Cam, 7 Pincer, 7 Cam+Pincer). Overall sensitivity, specificity, accuracy, PPV and NPV for dGEMRIC were 81%, 57%, 72%, 76% and 63%, compared to 37%, 90%, 56%, 86% and 45% for morphologic assessment. Inter and intra-observer variability for dGEMRIC were 6.9% and 7.4%, respectively.

Lesions in the hip acetabular cartilage are difficult to detect with standard morphologic evaluation even at high magnetic field strength. dGEMRIC performed along radial imaging planes of the hip at 3 T can effectively predict cartilage abnormalities and considerably improve preoperative evaluation of hip cartilage in FAI compared to morphologic MRI alone. Standardized dGEMRIC analysis is replicable and facilitates cartilage evaluation across FAI patient population.

dGEMRIC significantly improves evaluation of the hip cartilage in FAI and it is recommended for preoperative assessment, especially if Gadolinium is already beeing injected for indirect arthrography.

Lattanzi, R, Petchprapa, C, Ascani, D, Recht, M, Effective Prediction of Cartilage Damage in Femoroacetabular Impingement with Standardized dGEMRIC on Radial Imaging Planes at 3 Tesla.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12037637.html