Daichi Hayashi MBBS, PhD, Presenter: Nothing to Disclose

Mohamed Jarraya, Abstract Co-Author: Nothing to Disclose

Ali Guermazi MD, PhD, Abstract Co-Author: President, Boston Imaging Core Lab, LLC Research Consultant, Merck KGaA Research Consultant, Novartis AG Research Consultant, sanofi-aventis Group Research Consultant, Stryker Corporation Research Consultant, AstraZeneca PLC

Kent Chian Kwoh MD, Abstract Co-Author: Nothing to Disclose

Michael Hannon, Abstract Co-Author: Nothing to Disclose

Frank W. Roemer MD, Abstract Co-Author: Vice-President, Boston Imaging Core Lab LLC Shareholder, Boston Imaging Core Lab LLC Research Consultant, Merck KGaA

Susceptibility artifacts are commonly observed on gradient echo sequences in the tibio-femoral joint space of degenerative joints. Aim was to assess their frequency on dual-echo steady state (DESS) and intermediate-weighted fat-suppressed (IW fs) sequences and assess their associations with calcifications and joint space narrowing (JSN) on X-ray (XR), and meniscal tears in the medial tibiofemoral joint (TFJ).

346 knees of 177 subjects aged 35-65 with knee pain were included. 3T MRI was performed at baseline and 6-month follow-up (f/u). Anteroposterior knee XR was taken at baseline and linear/punctate calcifications within the medial TFJ and medial JSN was recorded. Linear/punctate hypointensities representing susceptibility artifacts in the TF joint space were assessed on coronal DESS and IW fs sequences. All assessments were performed blinded and in random order. XR, DESS and IW images were each read on separate reading sessions >2 weeks apart. Kappa statistics were applied to define agreement between findings on the baseline DESS/IW fs and XR.

The mean age of subjects was 52 (SD±6) years, 95 (54%) were men, and mean BMI was 29 (SD±4). Medial meniscal tears and medial JSN were seen in 126 (36%) and 44 (13%) knees, respectively. At baseline, 13 knees showed susceptibility artifacts on DESS, of which 6 were also seen at f/u and 7 disappeared. 6 incident artifacts were noted at f/u. Compared to knees without the artifact, knees with the artifact were more likely to have medial meniscal tears (9/13, 69% vs. 117/333, 35%, p=0.017) and medial JSN (5/13, 38%, vs. 39/333, 60%, p=0.016). On IW fs, only 4 of the 13 artifacts were observed at baseline. On XR, 7 knees showed calcifications, but only 2 corresponded to the artifact on DESS. Conversely, calcification was absent in 11 knees with the artifact on DESS. Agreement between DESS and IW was κ=0.46 (95%CI 0.17-0.75), and between DESS and XR was κ=0.18 (95%CI -0.06 - 0.42).

Susceptibility artifacts on gradient echo sequences in the medial TFJ are more frequently observed in knees with medial meniscal tears and medial JSN, but are rarely related to XR-detected calcifications. Longitudinal changes are commonly seen. Most of these artifacts likely present vacuum phenomenon.

Susceptibility artifacts are commonly seen in degenerative joints, fluctuate and are likely to represent vacuum phenomenon in the majority of cases. 

Hayashi, D, Jarraya, M, Guermazi, A, Kwoh, K, Hannon, M, Roemer, F, A Longitudinal Evaluation of Susceptibility Artifacts in the Tibio-Femoral Joint Space on Knee MRI and Their Relation with X-ray Detected Calcifications, Joint Space Narrowing and MRI-detected Meniscal Tears.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12043445.html