Comparison of oblique coronal images in knee of three-dimensional isotropic T2-weighted turbo spin echo MRI versus two-dimensional fast spin echo T2-weighted sequences for evaluation of posterior cruciate ligament injury.

OBJECTIVE: To compare image quality between three-dimensional volume isotropic turbo spin echo acquisition (3D VISTA) with the posterior cruciate ligament (PCL) view and two-dimensional (2D) fast spin echo (FSE) for evaluation of PCL injury. METHODS: This retrospective study included 60 patients with clinical suspicion of PCL injury who underwent both 2D FSE and 3D VISTA of the knee between January 2015 and December 2015. The diagnostic performance of each oblique coronal view and the combined images was evaluated for sensitivity, specificity and accuracy for diagnosing a PCL tear. The arthroscopically confirmed diagnoses were used as the reference standard. Data were analyzed using the McNemar test. RESULTS: The mean contrast-to-noise ratio was significantly higher for 3D VISTA than for 2D FSE. The two imaging modalities did not differ significantly in anatomical identification ability, with the exception of margin sharpness, which was inferior for 3D VISTA with Reader 2 (p = 0.038). When we classified the diagnoses of PCL injury as normal or abnormal, there were no significant differences in sensitivity, specificity or accuracy between the PCL view of 3D VISTA and 2D FSE images (p > 0.05). CONCLUSION: 3D VISTA had a superior contrast-to-noise ratio than 2D FSE and similar image quality in the evaluation of the PCL. The PCL view of 3D VISTA has the same diagnostic ability as 2D FSE in the diagnosis of PCL injury and can thus replace 2D FSE. Advances in knowledge: The oblique coronal view 3D VISTA MRI has similar diagnostic ability to 2D FSE in the diagnosis of PCL injury, and therefore 3D VISTA image can replace 2D FSE.

Usefulness of oblique coronal magnetic resonance images of the knee after posterior cruciate ligament reconstruction.

OBJECTIVE:: To know the usefulness of the oblique coronal view of the posterior cruciate ligament (PCL) in the evaluation of the graft normal anatomy and the diagnostic accuracy of combining the PCL view with orthogonal views for the evaluation of PCL graft failure or impingement after reconstruction procedures. METHODS:: This retrospective study included 54 patients who underwent PCL-view MRI after PCL reconstruction surgery. Anatomic identification of graft failure and impingement was scored by two radiologists. The ability to diagnose PCL graft failure with the PCL view, orthogonal view or combined PCL/orthogonal views was evaluated by calculating the sensitivity, specificity and accuracy. RESULTS:: The entire width discrimination scores and margin sharpness scores for the PCL view were significantly higher than those for the orthogonal view for both readers. The specificities and accuracies for the PCL view and the combined PCL/orthogonal views were higher than those for the orthogonal view alone, but these differences were not statistically significant. CONCLUSION:: The PCL view provided a better anatomic evaluation than the orthogonal view with regard to the entire width evaluation and margin sharpness evaluation of the PCL graft. The combined view of orthogonal and PCL views was slightly more sensitive and accurate, but not significantly so, in the diagnoses of graft failure and impingement. ADVANCES IN KNOWLEDGE:: The PCL view provided a better anatomic evaluation than the orthogonal view with regard to the entire width evaluation and margin sharpness evaluation of the PCL graft. The PCL view was slightly more sensitive and accurate, but not significantly so, in the diagnoses of graft failure and impingement.

Usefulness of the fast spin-echo three-point Dixon (mDixon) image of the knee joint on 3.0-T MRI: comparison with conventional fast spin-echo T2 weighted image.

OBJECTIVE: To compare the quality of two different imaging methods, three-point Dixon (mDixon) and fast spin-echo (FSE) T2 weighted image (T2WI) [and fat suppression (FS) T2WI], and to assess the utility of mDixon for the imaging of knee joint pathology. METHODS: This retrospective study included 66 patients who underwent both mDixon and FSE T2WI (and FS T2WI) of the knee joint. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the two sequences at the articular cartilage and ligament were measured. Two radiologists independently evaluated the anatomic identification score and diagnostic performances of the two sequences. RESULTS: The mean SNRs and CNRs of the patellar cartilage, femoral cartilage and anterior cruciate ligament (ACL) were significantly higher on T2WI and FS T2WI than on mDixon imaging, with the exception of the mean SNR of ACL on in-phase images. Most of the anatomic identification scores did not show significant differences, except for inferiorities of the in-phase mDixon in the evaluation of the cruciate ligament. There were no significant differences in sensitivity, specificity and accuracy between mDixon and T2WI regarding diagnostic performance. CONCLUSION: mDixon images have equivalent anatomic identification ability with the exception of cruciate ligament delineation on in-phase images and have a diagnostic performance comparable with that of FSE T2WI for meniscal, cartilage and ligament injuries of the knee joint. There would be a net saving in time, if mDixon was the only sequence used. ADVANCES IN KNOWLEDGE: The mDixon images have equivalent anatomic identification abilities, with the exception of cruciate ligament delineation on in-phase images and have a diagnostic performance comparable with that of FSE T2WI for meniscal, cartilage and ligament injuries of the knee joint.