LITHUANIAN UNIVERSITY OF HEALTH SCIENCE
DEPARTMENT OF RADIOLOGY
RAYDAN ZEIDAN
FACULTY OF MEDICINE
GROUP 32
Y: 2018
Table of contents:
1. Title page (pg.1)
2. Table of content (pg.2)
3. Summary (Pg.3)
4. Acknowledgments (Pg.3)
5. Conflicts of interest (Pg.3)
6. Ethics Committee Clearance (Pg.4)
7. Abbreviations (Pg.5)
8. Terms (Pg.5)
9. Introduction (Pg.5 - 6)
10. Aims and objectives (Pg. 6)
11. Literature review (pg.6-12)
12. Methodology and methods (pg.12-14)
13. Results (pg.14-16)
14. Discussion of results (pg.16-18)
15. Conclusion (pg.18)
Summary:
Name and Surname: Raydan Zeidan
Title: The accuracy of MRI in the diagnosis of meniscal tears.
Aim and objectives: The purpose of this retrospective study is to estimate the accuracy of MRI in the diagnosis of meniscal tear in 68 patients, during the period from 2013 -2018.
Methodology and participants:
Patients were selected of age interval between 30 and 68; they were excluded of having any other diseases. They were only diagnosed with meniscal tear. These patients underwent knee MRI and their radiological findings of meniscal tear were noted. Then they were hospitalized for knee arthroscopy, information of arthroscopic examination were noted.
The MRI of medial and lateral menisci was assessed for the presence of tear and both were graded in a scale ranging from 1 to 5. (1= definitely not a tear, 2= probably not a tear, 3= indeterminate or equivocal, 4=probably a tear, 5=definitely a tear).
Results and conclusion:
When grade 5 was considered a tear sensitivity and specificity were 0.92, 0.95 for MM, and 0.85, 0.91 for LM respectively, when grades 4 and 5 were considered at tear results were 0.97, 0.77 for MM and 0.89, 0.82 for LM, when grades 3 to 5 were considered a tear 0.99, 0.56, and 1.0, 0.63 were recorded. The positive predictive values (PPVs) of MRI for the medial meniscus were 99% grade 5, 50% grade 4, 33% grade 3, 25% grade 2, 0% grade 1. For the Lateral meniscus PPVs of MRI were 84% grade 5, 41% grade 4, 19% grade 3, 0% grade 2 and grade 1. Conclusions:
In the diagnosis of meniscal tears, MRI has a high accuracy if only definitive findings are considered a tear. Add to that the familiarity with secondary signs of meniscal tears between healths professionals can help reduce interpretation errors.
Acknowledgements:
A lot of time, work and effort were given to make this research possible. Thanks to everyone who gave their time support and advice.Abbreviation list:
MM (medial meniscus), LM (lateral meniscus), MRI (magnetic resonance imaging), ACL (anterior cruciate ligament), PPV (positive predictive value), NVP (negative predictive value), PCL
(posterior cruciate ligament), CI (confidence level), PD-weighted MRI (proton density weighted magnetic resonance imaging),
Terms:
Arthrography, Arthroscopy, bucket-handle meniscal tear, Coronal MR Image, Intercondylar notch, Meniscectomy, Sagittal MR image, Sensitivity, Specificity, ‘’two-slice-touch’’ MR imaging, youden index, Truncated meniscus, Ghost meniscus,
Introduction:
Meniscal tears are the most common cause of knee pain in young and older patients. [1 2] MRI has become the gold noninvasive standard for diagnosing meniscal tears of the knee [3]. Specified history and physical examination should be held in order to exclude any other conditions that lead to knee pain.
it is known that MRI could be used routinely in the diagnosis of meniscal injuries prior to
recommending arthroscopic examination and surgery . [6 7] Furthermore, patients’ history alone is insufficient as a diagnostic tool, nor is the clinical examination and tests. The criteria of MRI in diagnosing meniscal tear is well established, these criteria include deformity of the normal shape of the meniscus or increased intrameniscal signal contacting an articular surface of the meniscus [4,5].
Stoller et al. [8] were the first to state that increased signals on MRI within the meniscus corresponds to degenerative changes where as signals contacting the articular surface were evidence of a tear. De Smet and Tuite [9] then stated that positive predictive value (PPV) of MRI in the diagnoses of meniscal tear can be improved if a ‘’two-slice-touch’’ rule is done, where a tear can be visualized as an increased signal touching the articular surface on at least two slices. MRI demonstrates high sensitivity (93% for medial meniscus [MM] and 79% for the lateral meniscus [LM]) and specificity (88% for the MM and 96 % for the LM) for diagnosing meniscal tear [15].
However despite advances in imaging, MRI continues to have inherited limitations, especially for detection of small posterior horn tears and other tears that involve less than one third of the LM, in addition a high false-positive rate has been reported for longitudinal tears of the MM posterior horn, possibly secondary to incomplete visualization of the far periphery of the MM at arthroscopy or to spontaneous healing [13 14].
[10] It is important to make a diagnosis of the meniscal tear in order to specify the target treatment.
In our upcoming study we will encounter equivocal cases in which MRI findings are unclear if they show a degenerative finding or a meniscal tear.
[11 12] the evaluation and comparative accuracy of MRI in the diagnosis of meniscal tear, should be done in taking into consideration the gold standard of arthroscopic diagnosis.
Aims and objective:
The purpose of this retrospective study is to assess the accuracy of MRI in the patients with meniscal tear. During our research we gathered information of MRI in patients with meniscal tear; we considered the arthroscopic examination which is taken from surgical information as definitely accurate information about the meniscus. We compared the MRI results we gathered with these most accurate visualized meniscal conditions. Arthroscopy was considered 100 % accurate illustration.
In order to make this possible patients MRI for both LM and MM were divided in 5 different groups:
Grade 1: definitely not a tear, grade 2: probably not a tear, grade 3: indeterminate or equivocal, grade 4: probably a tear, grade 5: definitely a tear.
Then we estimate sensitivity specificity and the PPV, for every group.
These measurements and tests will be done on patients suspected for this disorder; we
collected all the data necessary according to the diagnostic criteria stated above. We excluded all secondary factors that can influence our study results.
This study was held in Kaunas Lithuania it helps finding new clinical characteristics and
confirming old ones, our hope is to develop a clearer picture and better understanding of this topic.
Literature review:
MR Imaging-based diagnosis of meniscal tears:
The prevalence of meniscal tear increase with age, meniscal tears are associated with degenerative joint diseases. Tears can occur more prominently in the posterior horn of the menisci, particularly encountering the MM. however in younger patients with acute knee injury LM tears are more common.
Tears isolated in the anterior horn are uncommon; they form 2% and 16 % of medial meniscus and Lateral meniscus respectively [16]. This phenomenon can change in the presence of ACL tears
which increase prevalence in peripheral tears, and decreased sensitivity for detection of LM tears on MR imaging (69% sensitivity, compared with 94% sensitivity in patients without ACL tears). So attention should be given in this area where a subtle peripheral tear may be present. [17]
MR imaging proved to be highly accurate for visualizing of meniscal tears, and it proofed to be highly cooperative with arthroscopic findings [18].
On MRI the normal view of meniscus is low signal intensity; however in children intensity can be increased due to normal high vascularization, in adults high intensity visualization is an indication for suspected meniscal tear.
MR imaging criteria for diagnosing a tear is viewed on bases of distortion in the absence of past surgery, and an increase intrasubstance signal intensity unequivocally contacting the articular surface. According to this criteria If these findings are seen on two or more images, that defines the ‘’two-slice-touch’’ rule, then the PPV for a tear is 94% in the MM and 96% in the LM, and the diagnosis of the MR image should be reported as a meniscal tear.
These findings must be reported in the same area on any two consecutive MR images, which can be two coronal images and two sagittal images, or one coronal and one sagittal image. If these findings are present on one image, then the PPV for tear is 43% in the MM and 18% in the LM, and there will be reported as a possible tear[16 17].
It is known that increased intrasubstance signal intensity without extension to the articular surface is not associated with a tear [18]. And this finding will not progress to a tear [19].
Most sagittal images are the main images for diagnosing meniscal tear, coronal images are more used for accurately characterizing various tear patterns. Small tears, bucket- handle tears,
horizontal tears of the body, may be difficult to be detected on sagittal images because of volume averaging; these tears are more precisely seen on coronal images [20].
Meniscal Tear Classifications
Conservative treatment, surgical repair, or partial or complete menisectomy are the major treatments for meniscal tears. Longitudinal tears are often more easier to repair, whereas other types of tears like horizontal and radial tears they may need to undergo a partial meniscectomy [21 22].
So when a meniscal tear is suspected in a patient, the primary assessment goes for identifying the type of tear and studying its morphological appearance, the most common types of meniscal tears are: horizontal, longitudinal, radial, root, complex, displaced and bucket-handle tear.
Horizontal Tear:
Horizontal tear runs parallel to the tibial plateau, it can pass through either one of the articular surfaces or the central free edge, and then it can extend toward the periphery, dividing the meniscus into superior and inferior parts[23] (figure 1).
Typical MR images appearance will be shown as a horizontally oriented line of high signal intensity that contacts the meniscal surface of the free edge [24].
Treatment involves debridement of the smaller unstable meniscal leaf; partial meniscectomy is the treatment of choice in this case [25].
a b
Figure 1, horizontal meniscal tear, a) sagittal MR image shows a tear of the posterior horn b) Arthroscopic cam showing horizontal meniscal tears.
Longitudinal tear:
A perpendicular tear line to the tibial plateau and parallel to the long axis of the meniscus is considered a longitudinal tear; also it divides the meniscus into central and peripheral halves. [23].
Unlike any other tears this type of meniscal tear do not involve the free edge of the meniscus, these types of tear more often occur in younger ages, following a knee trauma [26].
The MR image typically appears as a vertical orientated line of high signal intensity that contacts one or both articular surfaces (Figure 2).
Studies had shown that there is a combination between the occuring of longitudenal tears and ACL tears. Specifically, 90% of MM and 83% of LM longitudenal tears have an associated ACL tear [14].
It is known from experience that identifying peripheral longitudinal tears of the posterior horn of the LM can be difficult and that’s because of the complex posterior attachments of the meniscus.
a. b.
Figure 2: a) MR imaging shows longitudinal meniscal tear, b) it shows a 3D animation of repairing a longitudinal meniscal tear.
Radial tear:
A radial tear is the tear that runs perpendicular to both tibial plateau and the long axis of the meniscus, the direction of the tear protrudes the longitudinal collagen bundles as it extends from the free edge toward the periphery. The major difference between radial tears and other
horizontal and longitudinal tears is that radial tear disrupts the meniscal hoop strength, resulting in a dramatic loss of function and possible meniscal extrusion. This type of tear is difficult to repair, and therefore they have a very low tendency of healing, or regaining their major function. Add to that small radial tears are difficult to be detected, which results in their under diagnosis before surgery takes place [14 27].
Radial tears are mostly seen on the posterior horn of the MM or the junction between the anterior horn and the body of the LM. On MR images radial tear appear as clefts oriented perpendicular to the free edge.
Some imaging figures can be seen with a radial tear, examples include ‘’ truncated triangle’’, ‘’cleft’’, ‘’marching cleft’’, and ‘’ghost meniscus’’ signs.
As we look wisely on MR images of meniscal body would appear as a cleft on sagittal MR images and as a truncated or ghost meniscus on coronal MR images. On the other hand a tear through the horn would appear as a truncated or ghost meniscus on sagittal MR images, and a cleft on sagittal MR images.
‘’Truncated meniscus’’ shows truncation of the free edge, with preservation of its peripheral portion, often described as partial-thickness tear. On the other hand a ‘’ghost meniscus’’ has no residual normal meniscus, often as a result of a full-thickness tear.
If the tear is located at the junction of the horn and the body (seen obliquely in both coronal and sagittal plains) it would appear as a ‘’marching cleft’’ that can progresses away from the free edge on a continuous MR imaging sections.
These signs can lead us to differentiate between radial tears on MR image (Figure 3) [21 28].
Add to that, the cleft is a sign that can be seen in both longitudinal and radial tears, in coronal imaging if the cleft is within the body we can say that the tear is longitudinal, where as if the cleft is within the horn we can assume that the tear is radial tear. The opposite combination can be holding on sagittal images.
a. b.
Figure 3: a) arthroscopic image of radial tear, b) is an example of marching cleft tear, on coronal MRI view.
Root tears:
It is known as a radial type tear, these type of tears are associated with meniscal extrusion especially when the tear occurs in the MM [29 30]. Using a coronal fluid-sensitive MR images sequences allow better definition of the root, on coronal MR image, the root should course over its respective tibial plateau on at least one image. On sagittal MR image, if the posterior root of the MM is not detected just medial to the PCL, a root tear should be suspected. Add to that when an ACL tear is present there is an increase incidence of lateral root tear (Figure 4) [29, 31].
Complex Tear:
Complex tears include the combination of radial, horizontal, and longitudinal components (any two or all three). The meniscus will appear fragmented, with the tear extending in more than one plane (Figure 5).
Figure 5: an example of complex tear
Displaced Tear:
Displaced tears are represented as free fragments, displaced flap tears, and bucket-handle tears. These tears are represented clinically as mechanical obstruction that needs to be reattached surgically or by debridement. These kinds of tears as free fragments and flaps they can be missed during surgery, where they can result in persistent knee pain and locking, identifying them before surgery is important. Flap tears occur six to seven times more frequently in MM; two thirds of these tears are displaced posteriorly, in the remaining cases fragments displace into intercondylar notch or superior recess [32].
Bucket-handle Tear:
A bucket-handle Tear is described as a tear that runs longitudinally with a central migration of the inner ‘’handle’’ fragment. Studies showed that this tear had a probability of seven times to occur more in the MM [33]. And has at least five different MR imaging signs: an absent bow tie, a
fragment within the intercondylar notch, a double PCL, a double anterior horn or flipped meniscus, and a disproportionally small posterior horn [34-37].
Fraying:
At arthroscopy, fraying is defined as surface irregularity along the meniscal free edge without a discrete tear. Thinner sections of MRI has shown depiction of areas of meniscal fraying, that can involve the free edge of the body, posterior horn, posterior root ligament. [38]. In MRI the free edge may be viewed as loss of its sharp tapered central edge, and the posterior root ligament may show subtle, ill-defined, increased intrameniscal signal intensity contacting the articular surface.
It was noted that findings within posterior root ligament cannot be differentiated from a possible shallow partial-thickness tear, fraying, or surrounding synovitis. However many researches were done for this issue, a deferential diagnosis of synovitis, partial tear, or fraying can be used for equivocal findings in patients older than 40 years, excluding an acute traumatic event. However in younger patients after an acute trauma, LM posterior root show increase signal intensity
contacting the articular
Surface, that should be considered as a probable tear. Specificity decrease if equivocal or probable findings were considered a tear [40].
Diagnostic errors:
Diagnostic errors can be divided into false-negative and false-positive errors. False negative errors that can involve the LM, subsides when the tear is small and involves the posterior horn [4]. These errors can be anatomic (mistaken with normal anatomical anatomic structures), or technical (arterial pulsation or magic-angle effect that obscures a tear).
False positive errors include mistakes with anatomical structures and variants of meniscal tears. Other cases can be magic-angle, healed tears, limitation of arthroscopy.
The magical angle effect occurs when collagen fibers are oriented 55 degrees relative to the magical field, which can be often seen in the upslope medial segment of the LM posterior horn at imaging. This effect most commonly occurs within the posterior horn and appears as amorphous increased signal intensity that does not extent to the articular surface, particularly on non-fluid-sensitive PD-weighted MR images [38].
Healed tear can show abnormal increased signal intensity for an undefined period. To differentiate healed tears, possible access to arthrography, clinical history, physical examination may be subjected.
Research methodology and methods:
This research was done in Lithuanian university of health sciences hospital; its subject includes the estimation of accuracy of MRI in the diagnosis of meniscal tear. The Radiology department was included in this research as a provider of all information concerning MRI, as well as the Orthopedic and Traumatology department was included to provide information about arthroscopy.
In order to reach our concern, a group of 68 patients were selected. These patients were selected because they’ve done knee MRI and knee arthroscopy, the state of their meniscus was recorded in both findings. The purpose of these selected patients is to evaluate the accuracy of their MRI, taking into consideration the total accurate image of their meniscus seen on arthroscopy.
68 patients were selected, under the previous conditions mentioned above. They were hospitalized between years 2013-2018. Patient’s population included 35 women and 33 men, ranging in age from 30 to 68 years old. 48 % of these patients were at least 40 years old.
The shortest interval between MRI and arthroscopy was 1 day and the longest was 97 days.
Review of MRI examination:
Two fellowship-trained musculoskeletal radiologists with 4 and 6 years of experience reviewed the MRI examination in consensus. Both radiologists were blinded to the arthroscopic results. The medial and lateral menisci were assessed for the presence of tear and they were graded on a scale ranging from 1 to 5. (1=definitely not a tear, 2= probably not a tear, 3= indeterminate or
equivocal, 4=probably a tear, 5=definitely a tear).
Grade 5 was defined as a clear alteration of the morphology of the meniscus, increased proton density-weighted signal clearly touching a meniscal surface on at least two slices, and no artifacts limiting evaluation. Grade 4 was defined as increased signal on proton density-weighted images clearly extending to an articular surface on only one image, plus grade 5 including artifacts. Grade 3 was defined as increased signal approaching the articular surface but not clearly extending to the surface on proton density-weighted images, it also includes any lesion which is not classifiable as grade 1, 2, 4 or 5. Grade 2 was defined as increased signal not extending to the articular surface on proton density- weighted images, and normal morphology; grade 1 was defined as no increase signal in the meniscus, normal morphology, and no artifacts limiting evaluation.
Review of operative findings:
Arthroscopic surgery was performed by 1 of 8 orthopedic surgeons. Each patient’s operative report and arthroscopic image was reviewed by orthopedic surgeon with 5 years experience and a postgraduate 4th year orthopedic surgeon resident. Both were blind to the preoperative MR images and reports. The presence or absence of a tear, fraying, and degeneration, was noted for both menisci.
Statistical analysis:
The sensitivity and specificity of MRI were calculated as a proportion with a positive test result among patients with a tear, and patients with negative test results among patients without a tear, respectively.
Positive test result was defined in 3 ways: first, grade 5 was considered positive, second, grade 4 and 5 were considered positive, third grade 3, 4 and 5 were considered positive. The operative findings were considered the gold standard, with tear considered a positive result and fraying, degeneration, and normal meniscus considered negative results. Asymptotic methods were used to construct 95% CIs for sensitivity and specificity. For estimates of 1, a 95% CIs was constructed using the rule of threes [39]. Predictive values were calculated for each of the five possible grades. The Youden index was computed for sensitivity and specificity of each MRI finding.
Findings with the highest youden index were included in a multiple-variable logistic regression model.
Results:
The sensitivity and specificity of MRI in the diagnosis of medial and lateral meniscal tear are listed in table number 1. The PPV of each MRI grade for diagnosing a meniscal tear is summarized in table 2. The operative findings and their corresponding MRI grades are summarized in table 3. In the study of meniscal tears, when indeterminate (grade 3) was considered a negative result, MRI sensitivity of 0.97 (95% CI, 0.92 – 1.0) and the specificity of 0.77 (95% CI, 0.57 –
0.97) was recorded. When grade 3 is considered a positive result, MRI had a sensitivity of 0.99 (95% CI, 0.97 – 1.0) and a specificity of 0.56 (95% CI, 0.46 – 0.66). In case of lateral tears, when cases of group 3 were considered a negative result, MRI had a sensitivity of
0.89(95% CI, 0.78 – 1.0) and a specificity of 0.82(95% CI, 0.72 – 0.92). And when indeterminate cases (grade3) were considered a positive result, MRI sensitivity of 1.0(95% CI, 0.88 – 1.0) and a specificity of 0.63(95% CI, 0.45 – 0.78) was recorded.
For the medial meniscus 55 out of 68 cases (80%) were ‘’ definitely a tear ‘’ (grade 5), and only 6 cases (9%) were interpreted as grade 3 on MRI.
For the lateral meniscus only 52 out of 68 (76%) were interpreted as grade 5 on MRI. And 16 cases (23%) were interpreted as grade 3 on MRI.
Table 1: Sensitivity and Specificity of MRI in the diagnosis of meniscal tear.
Grade 5 defined tear grade 4 and 5 defined tear grade 3 – 5 defined tear
Location of tear on MM LM MM LM MM LM
Arthroscopy
Sensitivity % 92 85 97 89 99 100 Specificity % 95 91 77 82 56 63
*Grades were defined as follows: 1 = definitely not a tear, 2 = probably not a tear, 3 = indeterminate or equivocal, 4 = probably a tear, 5 = definitely a tear. *MM=medial meniscus LM=lateral meniscus
Table 2: positive predictive value by MRI grades in the diagnosis of meniscal tear. Number of tears detected at surgery/number of lesions at MRI by grades (%)
Grade 1 Grade 2 Grade 3 Grade4 Grade 5 Medial meniscus 0/5 (0) 1/4 (25) 2/6 (33) 4/8 (50) 49/50 (99) Lateral meniscus 0/27 (0) 0/6 (0) 3/16 (19) 5/12(41) 21/25 (84)
*Grades were defined as follows: 1 = definitely not a tear, 2 = probably not a tear, 3 = indeterminate or equivocal, 4 = probably a tear, 5 = definitely a tear.
Table 3: Arthroscopic results distributed among MRI grades. MRI Grades Arthroscopy total 1 2 3 4 5 MM LM MM LM MM LM MM LM MM LM MM LM Normal 9 20 3 10 1 4 3 4 2 2 0 0 Degeneration 4 2 2 1 0 0 1 0 0 1 1 0 Fraying 2 17 0 3 1 2 0 9 1 1 0 2 Tear 53 29 0 0 1 0 2 3 4 5 49 21
*MM=medial meniscus, LM=lateral meniscus
*Grades were defined as follows: 1 = definitely not a tear, 2 = probably not a tear, 3 = indeterminate or equivocal, 4 = probably a tear, 5 = definitely a tear.
In both cases in medial and lateral meniscal tear, all interpretations were correct according to operation in grade 1 patients, where as in grade 2 the interpretation of MRI matched the operation results in 70 % of cases of the medial meniscus and matches 98 % of the lateral meniscus.
When the MRI interpretation was probably a tear (grade 4), these interpretations were correct according to the operative findings in 50% of cases for the medial meniscus and in 41% of cases for the lateral meniscus. Whereas when the MRI interpretation was grade 5, this finding matched the operative views in 99% of cases in medial meniscus and 84% of cases in the lateral meniscus. In the case of medial meniscus MRI interpretation of grade 3 in operative findings revealed a tear in two of six cases (33%), the remaining four cases three were normal, and one showed
degenerative changes at arthroscopy. For the lateral meniscus when the MRI interpretation was grade 3, operative findings showed tear in three out of 16 cases (19%), the remaining 13 cases were 9 fraying and 4 normal as they showed on arthroscopy. The meniscal abnormalities observed on MRI were located in the body of the meniscus in 11 out of 16 cases, in the posterior horn in 3 cases, and in the anterior horn in 2 cases. The free edge of the meniscus was involved in 12 cases. And posterior horn was involved in 3 cases.
None of these MRI finding for diagnosing meniscal tear had a high sensitivity or specificity, its logical because of the selective nature of cases, the size of the sample taken for analysis, and the youden index was highly variable and of limited utility.
In our study there were 5 discordant cases excluding grade 3, four cases were false-positive and 1 case false-negative. On the other hand there were 11 discordant cases, 11 false-positive and 0 false negative. As our study went further we encounter most abnormalities in the posterior horn of the medial meniscus, the free edge of the medial meniscus was involved in only 3 cases. And the posterior root was involved in 1 case. On the other hand, on the lateral meniscus most lesions were located on the free edge of meniscus (10 cases) and lesions on the body were 8 out of 13 cases. The retrospective view of the discordant cases (n=16) and equivocal cases (n=21) including the knowledge gathered from surgery, All these together didn’t show any result that would improve the accuracy of MRI in the diagnosis of meniscal tears.
Discussion:
In this research that studied the accuracy of MRI in patients with meniscal tear, we found that the sensitivity of MRI was high, whereas the specificity had varying results. Add to that equivocal MRI findings for a tear were more likely to show degenerative changes or fraying more than tears, as they were accurately viewed on surgery.
MRI has become a routine part of clinical practice for the diagnosis of meniscal tear, and the accuracy of this image had extensively reported in the literature [40]. Oei et al. performed 29 published articles concerning the study of accuracy of MRI in the diagnosis of meniscal and cruciate ligament tears, they show sensitivity and specificity of 93% and 88% for medial meniscus
respectively, and 79% and 96% for lateral meniscus tears. The mean age of the patients ranged between 30 and 40 years.
Some other researchers also did similar studies. Jerosch et al [41] found that asymptomatic patients with age more than 50 years had a high occurrence of degenerative changes or meniscal tears when they were assessed with standard MRI criteria. In case of Boden et al. [42] his study reported that 36% of asymptomatic patients with meniscal tear, aged older than 45 years had a meniscal tear according to standard MRI criteria.
In our practice, we encountered patients in this age group that have equivocal findings established from MRI diagnosis of meniscal tear, in this category MRI showed questionable articular surface or free edge irregularity with increased intrameniscal signal that approaches the articular surface but it does not touch the surface. However it’s difficult to assess if these findings correspond to
meniscal tear or not. In this research we studied 68 patients in an interval between 40 and 68 years old, sensitivity and specificity for these patients according to MRI in the diagnosis of meniscal tear, were close to the results established by Oei et al. for younger population, which reported a sensitivity and specificity of 91% and 94% respectively for medial meniscus, and 73% and 91% for lateral meniscus, when only the patients surely diagnosed with meniscal tear (grade 5) are taken into consideration. If probable findings were considered a tear (grade 4) the
sensitivity increased to 96% and 88% for medial and lateral meniscus respectively, but the
specificity dropped to 76% and 80%, respectively. De Smet and Tuite [43] reported similar results but in different patients population this study showed sensitivity of 95% and 77% for the medial and lateral menisci respectively, and specificity of 85% and 89% when a meniscal tear was defined as signal touching the surface on single slice. On the other hand when equivocal (grade3) were considered a tear, the sensitivity rose to 99% for medial meniscus and 100% for the lateral meniscus but specificity dropped dramatically to 47% and 61% respectively.
In this study 30% of patients were considered as equivocal on MRI findings, with more cases were observed on lateral meniscus than medial meniscus. In most of these cases meniscal tears were not found in surgery, with a PPV of only 33% for medial meniscus and 23% for lateral meniscus. These findings in this study were similar to the younger population findings, where these results represent meniscal signal that does not extend to the surface is unlikely to present a tear. In these equivocal and discordant cases, the most common site of abnormality was in the free edge of the lateral meniscus. There was no MRI finding that would represent a high percentage of sensitivity and specificity can additionally help with the diagnosis of meniscal tear prior to surgery. The design of our study had several limitations, first the small amount of patients recorded had interfered in the statistical correlation in our study, in a way for the presence or absence of the tear. Only patients who were invited to MRI were included in our research, add to that this number of patients underwent surgery as well, not including patients with any other diseases or disabilities. The interpretation of these selected patients MRI gave the clue if these patients will undergo surgery or not, some patients underwent surgery before MRI, which led readers to evaluate their meniscal state MRI based on their surgical findings. Also the surgical finding weren’t so accurate in the description of the patient’s meniscal tear; that had some limitation on our study evaluation. I interfered sometimes asking for videos and pictures of these patients knee surgeries to evaluate their meniscus by myself and asking a surgeon decision. And that also happened on MRI where I viewed some patients knee MRI in order to accomplish my target. The classification of meniscal tear in these patients as degenerative, fraying, and tear at
arthroscopy, made a wide range of interpretation in this study; where in some cases fraying on surgical interpretation would change to tear if other surgeons performed that Operation.
The surgeons that were included in this study and that performed the arthroscopy believe that regardless these types of findings ‘’degenerative’’, ’’ fraying’’, ‘’tear’’, on arthroscopy if the patient didn’t have any symptoms that represent a meniscal tear then they don’t require a
surgery at all. In several cases in these indeterminate patients MRI grade, the patient’s findings at Surgery showed a smooth margin of their meniscus in ‘’degenerative’’ ‘’fraying’’ classifications, but these same patients often had other indications for surgery such as a contralateral meniscal tear. The point of discussion here is that indeterminate meniscal lesion alone does not necessitate a surgery.
Conclusion:
The main objective of this study was to find out the accuracy of MRI in the diagnosis of meniscal tear, the study took place in Lithuania in hospitalized patients selected between years 2013-2018. A study result like this can reveal a better interpretation of MRI findings, and can help in the future for deciding if a patient will undergo a surgery or not.
In conclusion the accuracy of MRI for diagnosing a meniscal tear is high and similar to the reported studies; which showed that a diagnosis of meniscal tear should be made only if there are definitive findings on MRI. The specificity of the equivocal or probable tear grades decreases on MRI
Because most of the times these findings don’t represent a tear at surgery. Statistically in these cases the specificity decreased from 77% to 56% in Medial meniscus, and from 82% to 63% in lateral meniscus on grade 3 which represent the equivocal cases.
In particularly, the MRI abnormalities involving the free edge of the body of the lateral meniscus should not be considered as a tear to prevent unnecessary surgical interventions, the reason of this conclusion was because the majority of equivocal cases were sent to surgery because of the nonspecific interpretation of MRI in this particular anatomic site.
MRI claims an accurate and a better understanding of the patient’s situation in case of meniscal tear; basically it can be instrumental for patient’s counseling and for surgery planning. With the application of the ‘’two-slice-touch’’ MR imaging theory, the accuracy for preoperative detection of meniscal tears became higher. From this retrospective study we determined that the familiarity with the normal anatomy, common anatomic variants, and indirect secondary signs of meniscal tear can help reduce interpretation errors. We concluded that because most of the equivocal findings that showed artifacts or other uncertain images on MRI were mistaken by meniscal tear.
1. Aagaard H, Verdonk R. Function of the normal meniscus and consequences of meniscal resection. Scand J Med Sci Sports. 1999;9(03):134–140.
2. Fox A J, Wanivenhaus F, Burge A J, Warren R F, Rodeo S A. The human meniscus: a review of anatomy, function, injury, and advances in treatment. Clin Anat. 2015;28(02):269–287. 3. Rosas HG, De Smet AA. Magnetic resonance imaging of the meniscus. Top Magn Reson
Imaging 2009; 20:151–173
4. Crues JV 3rd, Mink J, Levy TL, Lotysch M, Stoller DW. Meniscal tears of the knee: accuracy of MR imaging. Radiology 1987; 164:445–448
5. Reicher MA, Hartzman S, Duckwiler GR, Bassett LW, Anderson LJ, Gold RH. Meniscal injuries: detection using MR imaging. Radiology 1986; 159:753–757
6. Crawford R, Walley G, Bridgman S, Maffulli N. Magnetic resonance imaging versus
arthroscopy in the diagnosis of knee pathology, concentrating on meniscal lesions and ACL tears: a systematic review. Br Med Bull. 2007;84(01):5–23.
7. Rubin D A, Paletta G A., Jr Current concepts and controversies in meniscal imaging. Magn Reson Imaging Clin N Am. 2000;8(02):243–27.
8. Stoller DW, Martin C, Crues JV 3rd, Kaplan L, Mink JH. Meniscal tears: pathologic correlation with MR imaging. Radiology 1987; 163:731–735
9. De Smet AA, Tuite MJ. Use of the “two-slicetouch” rule for the MRI diagnosis of meniscal tears. AJR 2006; 187:911–914
10. Terry G C, Tagert B E, Young M J. Reliability of the clinical assessment in predicting the cause of internal derangements of the knee. Arthroscopy. 1995;11(05):568–576.
11. Esmaili Jah A A, Keyhani S, Zarei R, Moghaddam A K. Accuracy of MRI in comparison with clinical and arthroscopic findings in ligamentous and meniscal injuries of the knee. Acta Orthop Belg. 2005;71(02):189–196.
12. Scholten R J, Devillé W L, Opstelten W, Bijl D, van der Plas C G, Bouter L M. The accuracy of physical diagnostic tests for assessing meniscal lesions of the knee: a meta-analysis. J Fam Pract. 2001;50(11):938–944.
13. De Smet AA, Mukherjee R. Clinical, MRI, and arthroscopic findings associated with failure to diagnose a lateral meniscal tear on knee MRI. AJR Am J Roentgenol 2008;190(1):22–26. 14. De Smet AA, Nathan DH, Graf BK, Haaland BA, Fine JP. Clinical and MRI findings associated
with falsepositive knee MR diagnoses of medial meniscal tears. AJR Am J Roentgenol 2008;191(1):93–99.
15. Oei EH, Nikken JJ, Verstijnen AC, Ginai AZ, Myriam Hunink MG. MR imaging of the menisci and cruciate ligaments: a systematic review. Radiology 2003;226(3): 837–848.
16. De Smet AA, Norris MA, Yandow DR, Quintana FA, Graf BK, Keene JS. MR diagnosis of meniscal tears of the knee: importance of high signal in the meniscus that extends to the surface. AJR Am J Roentgenol 1993; 161(1):101–107.
17. De Smet AA, Graf BK. Meniscal tears missed on MR imaging: relationship to meniscal tear patterns and anterior cruciate ligament tears. AJR Am J Roentgenol 1994;162(4):905–911. 18. Crues JV 3rd, Mink J, Levy TL, Lotysch M, Stoller DW. Meniscal tears of the knee: accuracy
19. Crema MD, Hunter DJ, Roemer FW, et al. The relationship between prevalent medial meniscal intrasubstance signal changes and incident medial meniscal tears in women over a 1-year period assessed with 3.0 T MRI. Skeletal Radiol 2011;40(8):1017–1023
20. Magee T, Williams D. Detection of meniscal tears and marrow lesions using coronal MRI. AJR Am J Roentgenol 2004;183(5):1469–1473.
21. Harper KW, Helms CA, Lambert HS 3rd, Higgins LD. Radial meniscal tears: significance, incidence, and MR appearance. AJR Am J Roentgenol 2005;185(6): 1429–1434.
22. Fox MG. MR imaging of the meniscus: review, current trends, and clinical implications. Radiol Clin North Am 2007;45(6):1033–1053,
23. Rubin DA. MR imaging of the knee menisci. Radiol Clin North Am 1997;35(1):21–44. 24. Ferrer-Roca O, Vilalta C. Lesions of the meniscus. II. Horizontal cleavages and lateral cysts.
Clin Orthop Relat Res 1980;(146):301–307
25. Reagan WD, McConkey JP, Loomer RL, Davidson RG. Cysts of the lateral meniscus: arthroscopy versu
26. Dandy DJ. The arthroscopic anatomy of symptomatic meniscal lesions. J Bone Joint Surg Br 1990;72(4): 628–633.
27. Tuckman GA, Miller WJ, Remo JW, Fritts HM, Rozansky MI. Radial tears of the menisci: MR findings. AJR Am J Roentgenol 1994;163(2):395–400s arthroscopy plus open cystectomy. Arthroscopy 1989;5 (4):274–281.
28. Magee T, Shapiro M, Williams D. MR accuracy and arthroscopic incidence of meniscal radial tears. Skeletal Radiol 2002;31(12):686–689.
29. Brody JM, Lin HM, Hulstyn MJ, Tung GA. Lateral meniscus root tear and meniscus extrusion with anterior cruciate ligament tear. Radiology 2006;239(3):805–810.
30. Choi CJ, Choi YJ, Lee JJ, Choi CH. Magnetic resonance imaging evidence of meniscal extrusion in medial meniscus posterior root tear. Arthroscopy 2010;26 (12):1602–1606. 31. De Smet AA, Blankenbaker DG, Kijowski R, Graf BK, Shinki K. MR diagnosis of posterior root
tears of the lateral meniscus using arthroscopy as the reference standard. AJR Am J Roentgenol 2009;192(2):480–486.
32. Vande Berg BC, Malghem J, Poilvache P, Maldague B, Lecouvet FE. Meniscal tears with fragments displaced in notch and recesses of knee: MR imaging with arthroscopic comparison. Radiology 2005;234(3): 842–850.
33. Shakespeare DT, Rigby HS. The bucket-handle tear of the meniscus: a clinical and arthrographic study. J Bone Joint Surg Br 1983;65(4):383–387
34. Ververidis AN, Verettas DA, Kazakos KJ, Tilkeridis CE, Chatzipapas CN. Meniscal bucket handle tears: a retrospective study of arthroscopy and the relation to MRI. Knee Surg Sports Traumatol Arthrosc 2006;14(4): 343–349.
35. Dorsay TA, Helms CA. Bucket-handle meniscal tears of the knee: sensitivity and specificity of MRI signs. Skeletal Radiol 2003;32(5):266–272.
36. Magee TH, Hinson GW. MRI of meniscal buckethandle tears. Skeletal Radiol 1998;27(9):495–499.
37. Haramati N, Staron RB, Rubin S, Shreck EH, Feldman F, Kiernan H. The flipped meniscus sign. Skeletal Radiol 1993;22(4):273–277.
38. Peterfy CG, Janzen DL, Tirman PF, van Dijke CF, Pollack M, Genant HK. “Magic-angle” phenomenon: a cause of increased signal in the normal lateral meniscus on short-TE MR images of the knee. AJR Am J Roentgenol 1994;163(1):149–154.
39. Jung JY, Yoon YC, Kwon JW, Ahn JH, Choe BK. Diagnosis of internal derangement of the knee at 3.0-T MR imaging: 3D isotropic intermediate-weighted versus 2D sequences. Radiology 2009;253(3):780–787.
40. Rosas HG, De Smet AA. Magnetic resonance imaging of the meniscus. Top Magn Reson Imaging 2009; 20:151–173
41. Jerosch J, Castro WH, Assheuer J. Age-related magnetic resonance imaging morphology of the menisci in asymptomatic individuals. Arch Orthop Trauma Surg 1996; 115:199–202 42. Boden SD, Davis DO, Dina TS, et al. A prospective and blinded investigation of magnetic
resonance imaging of the knee: abnormal findings in asymptomatic subjects. Clin Orthop Relat Res 1992; 282:177–185
43. De Smet AA, Tuite MJ. Use of the “two-slicetouch” rule for the MRI diagnosis of meniscal tears. AJR 2006; 187:911–914
Santrauka
Vardas ir pavardė: Raydan Zeidan
Pavadinimas: MRT tikslumas menisko plyšimo diagnostikoje
Tikslas ir uždaviniai: Šio retrospektyviojo tyrimo tikslas yra įvertinti magnetinio rezonanso
tikslumą menisko plyšimo diagnostikoje 68 pacientams laikotarpiu nuo 2013 iki 2018metų.
Metodologija ir dalyviai:
Tyrimui atrinkti pacientai nuo 30 iki 68 metų amžiaus. Gretutinių ligų jiems nenustatyta. Visiems jiems nustatytas menisko plyšimas . Taip pat jiems atliktas kelio sąnario MRT tyrimas ir jo metu buvo įtartas menisko plyšimas. Atsižvelgiant į MRT tyrimo diagnozę šie pacientai buvo hospitalizuoti, numatant jiems atlikti artroskopiją. Įvertinti artroskopinio tyrimo rezultatai.
Buvo veritami įvairių lokalizacijų meniskų plyšimai (priekiniai ir šoniniai) ir gauti rezultatai buvo vertinami pagal skalę nuo 1 iki 5. (1 = plyšimo nėra, 2 = pakitimai mažiau būdingi plyšimui , 3 = plyšimo tikimybė apie 50 proc., 4 = pakitimai labiau panašūs į plyšimą, 5 = neabejotinas menisko plyšimas)
Rezultatų aptarimas :
5- skalės pacientams MRT tyrimo jautrumas ir specifiškumas buvo 0,92, 0,95 už MM ir atitinkamai 0,85, 0,91 atitinkamai LM, 4 ir 5 skalės pacientų MRT rezultatai buvo 0,97, 0,77 MM ir 0,89, 0,82 LM, kai pacientai buvo priskiriami 3-5 skalei, MRT tyrimo jautrumas ir specifiškumas siekė 0,99, 0,56 ir 1,0, 0,63. MRT teigiamos prognostinės vertės (PPV) medialinio menisko plyšimo atveju buvo 99 proc. (5 skalės reikšmė), 50 proc. - 4 reikšmė, 33 proc. - 3 reikšmė, 25 proc. - 2 reikšmė, 0 proc. - 1 reikšmė. Dėl šoninio menisko plyšimo MRT teigiamos prognostinės vertės 5-os skalės pacientams buvo 84 proc. 5, 41% - 4 skalės pacientams, 19% - 2 skalės pacientams ir 0% - 2 ir 1 skalės tiriamiesiems.
Išvados :
MRT tikslumas diagnozuojant menisko plyšimą yra labai didelis, ypač tais atvejais, kuomet yra neabejotinas plyšimas. Klinikinių ir radiologinių duomenų tarpusavio analizė
klinicistams gali padėti išvengti arba ženkliai sumažinti menisko plyšimo diagnostikos klaidų.
