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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

Grade 1 versus grade 2 anterior cruciate ligament graft injury.A. Sagittal T2-weighted image (TR/TE, 2200/90) shows lack of continuity and indistinct contour (arrows) of anterior cruciate ligament graft, suggesting grade 2 injury.B. Oblique coronal T2-weighted image (TR/TE, 3000/96) shows diffuse thinning, but also partially preserved continuity (arrows), suggesting grade 1 injury. Arthroscopic examination four weeks later confirmed grade 1 injury with graft attenuation with two thirds residual mass.
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Figure 4: Grade 1 versus grade 2 anterior cruciate ligament graft injury.A. Sagittal T2-weighted image (TR/TE, 2200/90) shows lack of continuity and indistinct contour (arrows) of anterior cruciate ligament graft, suggesting grade 2 injury.B. Oblique coronal T2-weighted image (TR/TE, 3000/96) shows diffuse thinning, but also partially preserved continuity (arrows), suggesting grade 1 injury. Arthroscopic examination four weeks later confirmed grade 1 injury with graft attenuation with two thirds residual mass.

Mentions: The MR grades of the ACL graft injury for each reader and each imaging group are summarized in Tables 1 and 2, respectively. The diagnostic agreements between the MR grade and the arthroscopic grade for imaging group A were considered "moderate" with weighted kappa values of 0.555 (reader 1) and 0.515 (reader 2). On the other hand, those for imaging group B were "substantial" with weighted kappa values of 0.666 (reader 1) and 0.611 (reader 2). Between the two imaging groups, a mismatch was noted for seven cases (downgrading for 6 and upgrading for 1) by reader 1; there were mismatches for eight cases (downgrading for 5 and upgrading for 3) by reader 2. The readers reached the correct diagnoses in eight cases (5 cases by reader 1 and 3 cases by reader 2) of the 11 cases for which they downgraded an ACL graft injury on the oblique coronal imaging, and the arthroscopic results were seven cases with an intact graft and one case with a partially torn graft (Figs. 3, 4). In three cases (1 case by reader 1 and 2 cases by reader 2) of the four upgraded cases, the correct diagnoses were achieved on the oblique coronal imaging and the arthroscopic results were two cases with a partially torn graft and one case with a completely torn graft.


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)

Grade 1 versus grade 2 anterior cruciate ligament graft injury.A. Sagittal T2-weighted image (TR/TE, 2200/90) shows lack of continuity and indistinct contour (arrows) of anterior cruciate ligament graft, suggesting grade 2 injury.B. Oblique coronal T2-weighted image (TR/TE, 3000/96) shows diffuse thinning, but also partially preserved continuity (arrows), suggesting grade 1 injury. Arthroscopic examination four weeks later confirmed grade 1 injury with graft attenuation with two thirds residual mass.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: Grade 1 versus grade 2 anterior cruciate ligament graft injury.A. Sagittal T2-weighted image (TR/TE, 2200/90) shows lack of continuity and indistinct contour (arrows) of anterior cruciate ligament graft, suggesting grade 2 injury.B. Oblique coronal T2-weighted image (TR/TE, 3000/96) shows diffuse thinning, but also partially preserved continuity (arrows), suggesting grade 1 injury. Arthroscopic examination four weeks later confirmed grade 1 injury with graft attenuation with two thirds residual mass.
Mentions: The MR grades of the ACL graft injury for each reader and each imaging group are summarized in Tables 1 and 2, respectively. The diagnostic agreements between the MR grade and the arthroscopic grade for imaging group A were considered "moderate" with weighted kappa values of 0.555 (reader 1) and 0.515 (reader 2). On the other hand, those for imaging group B were "substantial" with weighted kappa values of 0.666 (reader 1) and 0.611 (reader 2). Between the two imaging groups, a mismatch was noted for seven cases (downgrading for 6 and upgrading for 1) by reader 1; there were mismatches for eight cases (downgrading for 5 and upgrading for 3) by reader 2. The readers reached the correct diagnoses in eight cases (5 cases by reader 1 and 3 cases by reader 2) of the 11 cases for which they downgraded an ACL graft injury on the oblique coronal imaging, and the arthroscopic results were seven cases with an intact graft and one case with a partially torn graft (Figs. 3, 4). In three cases (1 case by reader 1 and 2 cases by reader 2) of the four upgraded cases, the correct diagnoses were achieved on the oblique coronal imaging and the arthroscopic results were two cases with a partially torn graft and one case with a completely torn graft.

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