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Multiparametric MRI of Epiphyseal Cartilage Necrosis (Osteochondrosis) with Histological Validation in a Goat Model.

Wang L, Nissi MJ, Tóth F, Shaver J, Johnson CP, Zhang J, Garwood M, Carlson CS, Ellermann JM - PLoS ONE (2015)

Bottom Line: All relaxation time constants differentiated normal epiphyseal cartilage from lesions of ischemic cartilage necrosis, and the histological staining results confirmed the proteoglycan (PG) loss in the areas of ischemia.In the scanned specimens, all of the measured relaxation time constants were higher in the articular than in the normal epiphyseal cartilage, consistently allowing differentiation between these two tissues.Multiparametric MRI provided a sensitive approach to discriminate between necrotic and viable epiphyseal cartilage and between articular and epiphyseal cartilage, which may be useful for diagnosing and monitoring OC lesions and, potentially, for assessing effectiveness of treatment interventions.

View Article: PubMed Central - PubMed

Affiliation: Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States of America; Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, United States of America.

ABSTRACT

Purpose: To evaluate multiple MRI parameters in a surgical model of osteochondrosis (OC) in goats.

Methods: Focal ischemic lesions of two different sizes were induced in the epiphyseal cartilage of the medial femoral condyles of goats at 4 days of age by surgical transection of cartilage canal blood vessels. Goats were euthanized and specimens harvested 3, 4, 5, 6, 9 and 10 weeks post-op. Ex vivo MRI scans were conducted at 9.4 Tesla for mapping the T1, T2, T1ρ, adiabatic T1ρ and TRAFF relaxation times of articular cartilage, unaffected epiphyseal cartilage, and epiphyseal cartilage within the area of the induced lesion. After MRI scans, safranin O staining was conducted to validate areas of ischemic necrosis induced in the medial femoral condyles of six goats, and to allow comparison of MRI findings with the semi-quantitative proteoglycan assessment in corresponding safranin O-stained histological sections.

Results: All relaxation time constants differentiated normal epiphyseal cartilage from lesions of ischemic cartilage necrosis, and the histological staining results confirmed the proteoglycan (PG) loss in the areas of ischemia. In the scanned specimens, all of the measured relaxation time constants were higher in the articular than in the normal epiphyseal cartilage, consistently allowing differentiation between these two tissues.

Conclusions: Multiparametric MRI provided a sensitive approach to discriminate between necrotic and viable epiphyseal cartilage and between articular and epiphyseal cartilage, which may be useful for diagnosing and monitoring OC lesions and, potentially, for assessing effectiveness of treatment interventions.

No MeSH data available.


Related in: MedlinePlus

Linear regression analysis of the optical density experiment.(A) Light absorptions (A.U.) for viable (x, R2 = 0.129) and necrotic (o, R2 = 0.989) epiphyseal cartilage were fitted linearly to different time points, indicating that the PG content remained stable in the viable epiphyseal cartilage, but decreased linearly with time in the areas of chondronecrosis. (B) The % difference between light absorption by viable and necrotic epiphyseal cartilage was fitted linearly to different time points (R2 = 0.993). Although slight PG loss was observed in the 6-week sample, this point was excluded from the analysis because no histologically evident chondronecrosis was observed.
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pone.0140400.g003: Linear regression analysis of the optical density experiment.(A) Light absorptions (A.U.) for viable (x, R2 = 0.129) and necrotic (o, R2 = 0.989) epiphyseal cartilage were fitted linearly to different time points, indicating that the PG content remained stable in the viable epiphyseal cartilage, but decreased linearly with time in the areas of chondronecrosis. (B) The % difference between light absorption by viable and necrotic epiphyseal cartilage was fitted linearly to different time points (R2 = 0.993). Although slight PG loss was observed in the 6-week sample, this point was excluded from the analysis because no histologically evident chondronecrosis was observed.

Mentions: Decreased safranin O staining associated with PG loss resulted in a diminished light absorption in areas of cartilage necrosis (inside the black curves in Fig 2). Although no cartilage necrosis was identified in the sample obtained 6 weeks after surgery (Fig 1E), light absorption was decreased in the area adjacent to the incision (Fig 2E). The numerical values of the relative light absorption were established for the necrotic cartilage (inside all enclosed curves in Fig 1) and the normal epiphyseal cartilage (outside the curves in Fig 1, excluding articular cartilage). The optical density of viable epiphyseal cartilage fluctuated in a narrow range between 2.49 and 3.10 in all samples (Table 2) and indicated that the PG content was closely similar in the normal epiphyseal cartilage among the different juvenile goats. In contrast, light absorption decreased in areas of necrotic cartilage with increasing time after surgery, from 2.28 three weeks after surgery to 0.26 ten weeks after surgery (Table 2). The difference between light absorption of viable vs. necrotic cartilage increased linearly over time from 30.5% three weeks after surgery to 168% ten weeks after surgery (Fig 3). The lesion without histologically identifiable necrosis (6 weeks post surgery), however, only had 25% less light absorption than the normal epiphyseal cartilage and appears as an outlier when the data are graphed (Table 2 and Fig 3).


Multiparametric MRI of Epiphyseal Cartilage Necrosis (Osteochondrosis) with Histological Validation in a Goat Model.

Wang L, Nissi MJ, Tóth F, Shaver J, Johnson CP, Zhang J, Garwood M, Carlson CS, Ellermann JM - PLoS ONE (2015)

Linear regression analysis of the optical density experiment.(A) Light absorptions (A.U.) for viable (x, R2 = 0.129) and necrotic (o, R2 = 0.989) epiphyseal cartilage were fitted linearly to different time points, indicating that the PG content remained stable in the viable epiphyseal cartilage, but decreased linearly with time in the areas of chondronecrosis. (B) The % difference between light absorption by viable and necrotic epiphyseal cartilage was fitted linearly to different time points (R2 = 0.993). Although slight PG loss was observed in the 6-week sample, this point was excluded from the analysis because no histologically evident chondronecrosis was observed.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4608749&req=5

pone.0140400.g003: Linear regression analysis of the optical density experiment.(A) Light absorptions (A.U.) for viable (x, R2 = 0.129) and necrotic (o, R2 = 0.989) epiphyseal cartilage were fitted linearly to different time points, indicating that the PG content remained stable in the viable epiphyseal cartilage, but decreased linearly with time in the areas of chondronecrosis. (B) The % difference between light absorption by viable and necrotic epiphyseal cartilage was fitted linearly to different time points (R2 = 0.993). Although slight PG loss was observed in the 6-week sample, this point was excluded from the analysis because no histologically evident chondronecrosis was observed.
Mentions: Decreased safranin O staining associated with PG loss resulted in a diminished light absorption in areas of cartilage necrosis (inside the black curves in Fig 2). Although no cartilage necrosis was identified in the sample obtained 6 weeks after surgery (Fig 1E), light absorption was decreased in the area adjacent to the incision (Fig 2E). The numerical values of the relative light absorption were established for the necrotic cartilage (inside all enclosed curves in Fig 1) and the normal epiphyseal cartilage (outside the curves in Fig 1, excluding articular cartilage). The optical density of viable epiphyseal cartilage fluctuated in a narrow range between 2.49 and 3.10 in all samples (Table 2) and indicated that the PG content was closely similar in the normal epiphyseal cartilage among the different juvenile goats. In contrast, light absorption decreased in areas of necrotic cartilage with increasing time after surgery, from 2.28 three weeks after surgery to 0.26 ten weeks after surgery (Table 2). The difference between light absorption of viable vs. necrotic cartilage increased linearly over time from 30.5% three weeks after surgery to 168% ten weeks after surgery (Fig 3). The lesion without histologically identifiable necrosis (6 weeks post surgery), however, only had 25% less light absorption than the normal epiphyseal cartilage and appears as an outlier when the data are graphed (Table 2 and Fig 3).

Bottom Line: All relaxation time constants differentiated normal epiphyseal cartilage from lesions of ischemic cartilage necrosis, and the histological staining results confirmed the proteoglycan (PG) loss in the areas of ischemia.In the scanned specimens, all of the measured relaxation time constants were higher in the articular than in the normal epiphyseal cartilage, consistently allowing differentiation between these two tissues.Multiparametric MRI provided a sensitive approach to discriminate between necrotic and viable epiphyseal cartilage and between articular and epiphyseal cartilage, which may be useful for diagnosing and monitoring OC lesions and, potentially, for assessing effectiveness of treatment interventions.

View Article: PubMed Central - PubMed

Affiliation: Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States of America; Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, United States of America.

ABSTRACT

Purpose: To evaluate multiple MRI parameters in a surgical model of osteochondrosis (OC) in goats.

Methods: Focal ischemic lesions of two different sizes were induced in the epiphyseal cartilage of the medial femoral condyles of goats at 4 days of age by surgical transection of cartilage canal blood vessels. Goats were euthanized and specimens harvested 3, 4, 5, 6, 9 and 10 weeks post-op. Ex vivo MRI scans were conducted at 9.4 Tesla for mapping the T1, T2, T1ρ, adiabatic T1ρ and TRAFF relaxation times of articular cartilage, unaffected epiphyseal cartilage, and epiphyseal cartilage within the area of the induced lesion. After MRI scans, safranin O staining was conducted to validate areas of ischemic necrosis induced in the medial femoral condyles of six goats, and to allow comparison of MRI findings with the semi-quantitative proteoglycan assessment in corresponding safranin O-stained histological sections.

Results: All relaxation time constants differentiated normal epiphyseal cartilage from lesions of ischemic cartilage necrosis, and the histological staining results confirmed the proteoglycan (PG) loss in the areas of ischemia. In the scanned specimens, all of the measured relaxation time constants were higher in the articular than in the normal epiphyseal cartilage, consistently allowing differentiation between these two tissues.

Conclusions: Multiparametric MRI provided a sensitive approach to discriminate between necrotic and viable epiphyseal cartilage and between articular and epiphyseal cartilage, which may be useful for diagnosing and monitoring OC lesions and, potentially, for assessing effectiveness of treatment interventions.

No MeSH data available.


Related in: MedlinePlus