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Grading anterior cruciate ligament graft injury after ligament reconstruction surgery: diagnostic efficacy of oblique coronal MR imaging of the knee.

Moon SG, Hong SH, Choi JY, Jun WS, Choi JA, Park EA, Kang HS, Kwon JW - Korean J Radiol (2008 Mar-Apr)

Bottom Line: The weighted kappa values according to the routine knee MRI were 0.555 (reader 1) and 0.515 (reader 2).The inclusion of additional oblique coronal imaging increased the weighted kappa values to 0.666 (reader 1) and 0.611 (reader 2).The mean confidence levels by each reader were significantly higher (p < 0.01, paired t-test) with the additional oblique coronal imaging than by using the routine knee MRI alone.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Korea.

ABSTRACT

Objective: The purpose of this study was to evaluate the diagnostic efficacy of using additional oblique coronal MRI of the knee for grading anterior cruciate ligament (ACL) graft injury after ligament reconstruction surgery.

Materials and methods: We retrospectively reviewed 51 consecutive MR knee examinations of 48 patients who underwent both ACL reconstruction and follow-up arthroscopy. The MR examinations included the orthogonal axial, sagittal, coronal images and the oblique coronal T2-weighted images, which were oriented in parallel with the course of the femoral intercondylar roof. Two radiologists independently evaluated the status of the ACL grafts with using the routine knee MRI and then with adding the oblique coronal imaging. The severity of ACL graft injury was graded using a 3-point system from MR images as intact, partial tear or complete tear, and the results were compared with the arthroscopic results. Weighted kappa statistics were used to analyze the diagnostic accuracies of the knee MRI with and without the additional oblique coronal imaging. For each evaluation, the observers reported a confidence level for grading the ACL graft injuries in the two imaging groups.

Results: The weighted kappa values according to the routine knee MRI were 0.555 (reader 1) and 0.515 (reader 2). The inclusion of additional oblique coronal imaging increased the weighted kappa values to 0.666 (reader 1) and 0.611 (reader 2). The mean confidence levels by each reader were significantly higher (p < 0.01, paired t-test) with the additional oblique coronal imaging than by using the routine knee MRI alone.

Conclusion: The additional use of oblique coronal MRI of the knee improves both the diagnostic accuracy and confidence for grading ACL graft injury.

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Related in: MedlinePlus

Oblique coronal MR images of anterior cruciate ligament grafts.A. Sagittal T1-weighted MR image is used to localize oblique coronal imaging planes parallel to femoral intercondylar roof.B. Oblique coronal T2-weighted images (TR/TE, 3500/96) show homogeneously dark, straight ligament, suggesting intact anterior cruciate ligament graft (arrows) along its entire length. Both femoral (black arrowheads) and tibial (white arrowheads) sides are clearly demonstrated. Cross section of posterior cruciate ligament (thin arrow) is also shown.
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Figure 1: Oblique coronal MR images of anterior cruciate ligament grafts.A. Sagittal T1-weighted MR image is used to localize oblique coronal imaging planes parallel to femoral intercondylar roof.B. Oblique coronal T2-weighted images (TR/TE, 3500/96) show homogeneously dark, straight ligament, suggesting intact anterior cruciate ligament graft (arrows) along its entire length. Both femoral (black arrowheads) and tibial (white arrowheads) sides are clearly demonstrated. Cross section of posterior cruciate ligament (thin arrow) is also shown.

Mentions: MR examinations were performed on 1.0-T or 1.5-T MR scanners (Siemens, Erlangen, Germany). The MRI protocols included the sagittal spin echo T1-, the turbo spin echo T2- and the proton density-weighted images, the coronal turbo spin echo T2- and the proton density weighted images and the oblique coronal turbo spin echo T2-weighted images. The oblique coronal T2-weighted images were obtained in the plane parallel to the course of the femoral intercondylar roof on the sagittal scout images (Fig. 1). The parameters of the routine knee MRI were as follows: TR/TE = 500/12 (T1-weighted image), 3500/15 or 2200/14 (proton density weighted image), 3500/98 or 2200/90 (T2-weighted image), a 4-mm slice thickness, a 0.2-mm interval and a 256×256 or 512×512 matrix. The oblique coronal T2-weighted image parameters were as follows: TR/TE = 3000-4000/96, a 3-mm slice thickness, a 0.15-mm interval, a 256×256 or 512×512 matrix and a 3-minute 8-second or 3-minute 55-second acquisition time.


Grading anterior cruciate ligament graft injury after ligament reconstruction surgery: diagnostic efficacy of oblique coronal MR imaging of the knee.

Moon SG, Hong SH, Choi JY, Jun WS, Choi JA, Park EA, Kang HS, Kwon JW - Korean J Radiol (2008 Mar-Apr)

Oblique coronal MR images of anterior cruciate ligament grafts.A. Sagittal T1-weighted MR image is used to localize oblique coronal imaging planes parallel to femoral intercondylar roof.B. Oblique coronal T2-weighted images (TR/TE, 3500/96) show homogeneously dark, straight ligament, suggesting intact anterior cruciate ligament graft (arrows) along its entire length. Both femoral (black arrowheads) and tibial (white arrowheads) sides are clearly demonstrated. Cross section of posterior cruciate ligament (thin arrow) is also shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2627223&req=5

Figure 1: Oblique coronal MR images of anterior cruciate ligament grafts.A. Sagittal T1-weighted MR image is used to localize oblique coronal imaging planes parallel to femoral intercondylar roof.B. Oblique coronal T2-weighted images (TR/TE, 3500/96) show homogeneously dark, straight ligament, suggesting intact anterior cruciate ligament graft (arrows) along its entire length. Both femoral (black arrowheads) and tibial (white arrowheads) sides are clearly demonstrated. Cross section of posterior cruciate ligament (thin arrow) is also shown.
Mentions: MR examinations were performed on 1.0-T or 1.5-T MR scanners (Siemens, Erlangen, Germany). The MRI protocols included the sagittal spin echo T1-, the turbo spin echo T2- and the proton density-weighted images, the coronal turbo spin echo T2- and the proton density weighted images and the oblique coronal turbo spin echo T2-weighted images. The oblique coronal T2-weighted images were obtained in the plane parallel to the course of the femoral intercondylar roof on the sagittal scout images (Fig. 1). The parameters of the routine knee MRI were as follows: TR/TE = 500/12 (T1-weighted image), 3500/15 or 2200/14 (proton density weighted image), 3500/98 or 2200/90 (T2-weighted image), a 4-mm slice thickness, a 0.2-mm interval and a 256×256 or 512×512 matrix. The oblique coronal T2-weighted image parameters were as follows: TR/TE = 3000-4000/96, a 3-mm slice thickness, a 0.15-mm interval, a 256×256 or 512×512 matrix and a 3-minute 8-second or 3-minute 55-second acquisition time.

Bottom Line: The weighted kappa values according to the routine knee MRI were 0.555 (reader 1) and 0.515 (reader 2).The inclusion of additional oblique coronal imaging increased the weighted kappa values to 0.666 (reader 1) and 0.611 (reader 2).The mean confidence levels by each reader were significantly higher (p < 0.01, paired t-test) with the additional oblique coronal imaging than by using the routine knee MRI alone.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Korea.

ABSTRACT

Objective: The purpose of this study was to evaluate the diagnostic efficacy of using additional oblique coronal MRI of the knee for grading anterior cruciate ligament (ACL) graft injury after ligament reconstruction surgery.

Materials and methods: We retrospectively reviewed 51 consecutive MR knee examinations of 48 patients who underwent both ACL reconstruction and follow-up arthroscopy. The MR examinations included the orthogonal axial, sagittal, coronal images and the oblique coronal T2-weighted images, which were oriented in parallel with the course of the femoral intercondylar roof. Two radiologists independently evaluated the status of the ACL grafts with using the routine knee MRI and then with adding the oblique coronal imaging. The severity of ACL graft injury was graded using a 3-point system from MR images as intact, partial tear or complete tear, and the results were compared with the arthroscopic results. Weighted kappa statistics were used to analyze the diagnostic accuracies of the knee MRI with and without the additional oblique coronal imaging. For each evaluation, the observers reported a confidence level for grading the ACL graft injuries in the two imaging groups.

Results: The weighted kappa values according to the routine knee MRI were 0.555 (reader 1) and 0.515 (reader 2). The inclusion of additional oblique coronal imaging increased the weighted kappa values to 0.666 (reader 1) and 0.611 (reader 2). The mean confidence levels by each reader were significantly higher (p < 0.01, paired t-test) with the additional oblique coronal imaging than by using the routine knee MRI alone.

Conclusion: The additional use of oblique coronal MRI of the knee improves both the diagnostic accuracy and confidence for grading ACL graft injury.

Show MeSH
Related in: MedlinePlus