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Analysis of Low-Field Magnetic Resonance Imaging Scanners for Evaluation of Knee Pathology Based on Arthroscopy.

Lee CS, Davis SM, McGroder C, Stetson WB, Powell SE - Orthop J Sports Med (2013)

Bottom Line: Low-field MRI was an accurate tool for evaluation of medial meniscus and ACL tears.However, within the study population, it is not as effective in diagnosing lateral meniscus tears and showed a poor ability to detect osteochondral lesions.More information is needed to properly assess its ability to diagnose PCL tears.

View Article: PubMed Central - PubMed

Affiliation: Stetson Powell Orthopaedics and Sports Medicine, Burbank, California, USA.

ABSTRACT

Background: In recent years, few studies have evaluated low-field magnetic resonance imaging (MRI) diagnoses compared with intraoperative findings of the knee.

Purpose: To determine the accuracy and sensitivity of low-field MRI scanners in diagnosing pathology of the menisci, cruciate ligaments, and osteochondral surfaces.

Study design: Cohort study (diagnosis); Level of evidence, 2.

Methods: MRI examinations without intra-articular contrast were performed on 379 patients for knee pathologies over a 4-year period. The MRI examinations were done using a 0.2-tesla scanner utilizing a dedicated knee coil and read by 1 of 3 board-certified, musculoskeletal fellowship-trained radiologists. Within a mean time of 50 days after MRI, all patients underwent knee arthroscopy performed by 1 of 2 sports fellowship-trained orthopaedic surgeons. Operative notes from the knee arthroscopies were then reviewed by a single independent observer, and the intraoperative findings were compared with the MRI reports.

Results: For medial meniscus tears, the sensitivity, specificity, positive predictive value, and negative predictive value were 83%, 81%, 89%, and 71%, respectively. For lateral meniscus tears, the values were 51%, 93%, 84%, and 73%, respectively. For anterior cruciate ligament (ACL) tears, the values were 85%, 94%, 69%, and 97%, respectively. For osteochondral lesions, the values were 8%, 99%, 29%, and 94%, respectively. For posterior cruciate ligament (PCL) tears, the specificity and negative predictive value were 99% and 100%, respectively.

Conclusion: Low-field MRI was an accurate tool for evaluation of medial meniscus and ACL tears. However, within the study population, it is not as effective in diagnosing lateral meniscus tears and showed a poor ability to detect osteochondral lesions. More information is needed to properly assess its ability to diagnose PCL tears.

No MeSH data available.


Related in: MedlinePlus

True positive MRI and arthroscopic findings of a medial meniscus tear for a single patient. (A) Proton density–weighted oblique sagittal view using an E-scan Opera Esaote 0.2-tesla scanner. (B) Standard anterolateral viewing portal with 30° arthroscope evaluating medial meniscus.
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fig1-2325967113513423: True positive MRI and arthroscopic findings of a medial meniscus tear for a single patient. (A) Proton density–weighted oblique sagittal view using an E-scan Opera Esaote 0.2-tesla scanner. (B) Standard anterolateral viewing portal with 30° arthroscope evaluating medial meniscus.

Mentions: The low-field extremity MRI scanner used in this study was a good predictor of medial meniscus tears (sensitivity, 83%; specificity, 81%) (Figure 1), but not lateral meniscus tears (sensitivity, 51%; specificity, 93%) (Figure 2). Previous studies comparing low-field MRI to surgical findings have shown similar results for the medial meniscus (sensitivity, 77%-96%; specificity, 71%-100%), but lateral meniscus findings have commonly been much better (sensitivity, 75%-93%; specificity, 94%-100%).1,4,8,9,13,19,22,23,32 However, there have been 2 studies, by Kinnunen et al19 and Fischer et al,8 that showed low-field MRI to be a poor predictor of lateral meniscus tears (sensitivity, 25%-51%; specificity, 96%-97%). These findings match ours more closely, although it is unclear why our results may differ from the other studies. We are also unaware of any reason why such differences would exist between the medial and lateral menisci. Because of greater fixation, less mobility, and its function as a secondary stabilizer of anterior translation, medial meniscus tears tend to be more prevalent and more symptomatic.7,14 Fischer et al8 considered the fact that a greater incidence of medial meniscus tears may have caused the radiologists to anticipate findings and therefore “over-read” tears of the medial meniscus and “under-read” those of the lateral meniscus. We also found a greater number of medial meniscus tears (n = 250) than lateral meniscus tears (n = 158), and agree that this may have been a contributing factor. Similarly, high-field MRI has been shown to be a good predictor of medial meniscus (sensitivity, 89%-97%; specificity, 79%-100%) and lateral meniscus tears (sensitivity, 67%-96%; specificity, 91%-100%), with results for the lateral meniscus again being more variable.3,4,6,8,17,24,28,30


Analysis of Low-Field Magnetic Resonance Imaging Scanners for Evaluation of Knee Pathology Based on Arthroscopy.

Lee CS, Davis SM, McGroder C, Stetson WB, Powell SE - Orthop J Sports Med (2013)

True positive MRI and arthroscopic findings of a medial meniscus tear for a single patient. (A) Proton density–weighted oblique sagittal view using an E-scan Opera Esaote 0.2-tesla scanner. (B) Standard anterolateral viewing portal with 30° arthroscope evaluating medial meniscus.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4555514&req=5

fig1-2325967113513423: True positive MRI and arthroscopic findings of a medial meniscus tear for a single patient. (A) Proton density–weighted oblique sagittal view using an E-scan Opera Esaote 0.2-tesla scanner. (B) Standard anterolateral viewing portal with 30° arthroscope evaluating medial meniscus.
Mentions: The low-field extremity MRI scanner used in this study was a good predictor of medial meniscus tears (sensitivity, 83%; specificity, 81%) (Figure 1), but not lateral meniscus tears (sensitivity, 51%; specificity, 93%) (Figure 2). Previous studies comparing low-field MRI to surgical findings have shown similar results for the medial meniscus (sensitivity, 77%-96%; specificity, 71%-100%), but lateral meniscus findings have commonly been much better (sensitivity, 75%-93%; specificity, 94%-100%).1,4,8,9,13,19,22,23,32 However, there have been 2 studies, by Kinnunen et al19 and Fischer et al,8 that showed low-field MRI to be a poor predictor of lateral meniscus tears (sensitivity, 25%-51%; specificity, 96%-97%). These findings match ours more closely, although it is unclear why our results may differ from the other studies. We are also unaware of any reason why such differences would exist between the medial and lateral menisci. Because of greater fixation, less mobility, and its function as a secondary stabilizer of anterior translation, medial meniscus tears tend to be more prevalent and more symptomatic.7,14 Fischer et al8 considered the fact that a greater incidence of medial meniscus tears may have caused the radiologists to anticipate findings and therefore “over-read” tears of the medial meniscus and “under-read” those of the lateral meniscus. We also found a greater number of medial meniscus tears (n = 250) than lateral meniscus tears (n = 158), and agree that this may have been a contributing factor. Similarly, high-field MRI has been shown to be a good predictor of medial meniscus (sensitivity, 89%-97%; specificity, 79%-100%) and lateral meniscus tears (sensitivity, 67%-96%; specificity, 91%-100%), with results for the lateral meniscus again being more variable.3,4,6,8,17,24,28,30

Bottom Line: Low-field MRI was an accurate tool for evaluation of medial meniscus and ACL tears.However, within the study population, it is not as effective in diagnosing lateral meniscus tears and showed a poor ability to detect osteochondral lesions.More information is needed to properly assess its ability to diagnose PCL tears.

View Article: PubMed Central - PubMed

Affiliation: Stetson Powell Orthopaedics and Sports Medicine, Burbank, California, USA.

ABSTRACT

Background: In recent years, few studies have evaluated low-field magnetic resonance imaging (MRI) diagnoses compared with intraoperative findings of the knee.

Purpose: To determine the accuracy and sensitivity of low-field MRI scanners in diagnosing pathology of the menisci, cruciate ligaments, and osteochondral surfaces.

Study design: Cohort study (diagnosis); Level of evidence, 2.

Methods: MRI examinations without intra-articular contrast were performed on 379 patients for knee pathologies over a 4-year period. The MRI examinations were done using a 0.2-tesla scanner utilizing a dedicated knee coil and read by 1 of 3 board-certified, musculoskeletal fellowship-trained radiologists. Within a mean time of 50 days after MRI, all patients underwent knee arthroscopy performed by 1 of 2 sports fellowship-trained orthopaedic surgeons. Operative notes from the knee arthroscopies were then reviewed by a single independent observer, and the intraoperative findings were compared with the MRI reports.

Results: For medial meniscus tears, the sensitivity, specificity, positive predictive value, and negative predictive value were 83%, 81%, 89%, and 71%, respectively. For lateral meniscus tears, the values were 51%, 93%, 84%, and 73%, respectively. For anterior cruciate ligament (ACL) tears, the values were 85%, 94%, 69%, and 97%, respectively. For osteochondral lesions, the values were 8%, 99%, 29%, and 94%, respectively. For posterior cruciate ligament (PCL) tears, the specificity and negative predictive value were 99% and 100%, respectively.

Conclusion: Low-field MRI was an accurate tool for evaluation of medial meniscus and ACL tears. However, within the study population, it is not as effective in diagnosing lateral meniscus tears and showed a poor ability to detect osteochondral lesions. More information is needed to properly assess its ability to diagnose PCL tears.

No MeSH data available.


Related in: MedlinePlus