| objective:To explore the best sequence of knee cartilage imaging by investigating cartilage magnetic resonance imaging through signal-to-noise ratio (SNR) of knee and contrast-noise-ratio (CNR) and comparing the ability of showing the knee Cartilage lesions through taking the effect of arthroscopy (or surgery) results as gold standard. Methods:16 healthy volunteers (no trauma and knee disease history, knee asymptomatic, routine screening negative,8 males and 8 females, from 8 to 32 years, mean age 22.25 years) underwent three 3D sequence(3D-:FFE-SPIR,3D-FFE-WATS and 3D-FFE) scanning after conventional MR 2-D scanning. Measuring the signal intensity (SI) of articular cartilage,bone marrow,synovial fluid, muscles and background and calculating the signal-to-noise ratio (SNR) and contrast-noise-ratio (CNR) of various organizations according to the formula. In addition,117 patients who's knees are suspicious to be injuried (male 43 cases, female 74 cases, from 25 to 72 years, mean age 49.26±6.45 years, left knees 56, right knees of 61) underwented MR examinations and 52 knees among of them accepted the arthroscopy (or surgery) after the examination within one week knee mirrors (or surgery). Recording the extent of loss in every area (patellar articular surface, femoral condyle and medial wooden-horses, femoral femoral condyle, tibia medial platform and lateral platform) according the showing of MR and arthroscopy with the ameliorated Noyes grade. Using Excel and 2003SPSS 13.0 statistical packages for data entry and statistical analysis, comparing the differences SNR and CNR between different sequence, calculating and comparing the diagnosis of sensibility,specificity and accuracy to lesions cartilage with arthroscopy (or surgery) as the gold standard. Results: The SNR of cartilage in different sequence (3D-FFE-SPIR,3D-FFE-WATS and 3D-Balance-FFE) is 152.07±24.91,131.08±29.21,32.75±4.92,the difference was statistically significant (P<0.01). Comparing between any two Sequence of them:the difference between 3D-FFE-SPIR and 3D-FFE-WATS sequence was similar (P>0.05); the others are statistically significant (P<0.01). The SNR of bone marrow in different sequence is 17.27±2.78,19.9±1.95,60.26±11.19, the differences are statistically significant (P<0.01);Comparing between any two Sequence of them:the difference between 3D-FFE-SPIR and 3D-FFE-WATS sequence was similar (P>0.05); the others are statistically significant (P<0.01).The SNR of Synovial fluid in different sequence was73.03±12.25, 76.59±12.48,166.45±25.49,the differences were statistically significant (P<0.01);Comparing between any two Sequence of them:the difference between 3D-FFE-SPIR and 3D-FFE-WATS sequence was similar (P>0.05); the others are statistically significant (P<0.01). The SNR of muscle in different sequences was 90.86±18.62,93.1±18.92,17.41±2.51, the differences were statistically significant (P<0.01);Comparing between any two Sequence of them: the 3D-FFE-SPIR and 3D-FFE-WATS sequence was similar (P>0.05), the others are statistically significant (P<0.01). The CNR of articular cartilage/bone marrow in different sequences was 135.39±22.26,121.88±27.40,27.51±7.76; Comparing between any two Sequence of them:the difference between 3D-FFE-SPIR and 3D-FFE-WATS sequence was similar (P>0.05); the others are statistically significant (P<0.01).The CNR of articular cartilage/Synovial fluid in different sequences was 79.64±14.32,75.22±18.33,133.7±22.17,the difference were statistically significant (P<0.01); Comparing between two Sequence:the difference between 3D-FFE-SPIR and 3D-FFE-WATS sequence was similar (P>0.05), the others are statistically significant (P<0.01). The CNR of articular cartilage/muscle in different sequence is 61.81±9.8,38.91±11.68,15.33±3.06; the difference were statistically significant (P<0.01), Comparing between two Sequence:the difference between 3D-FFE-SPIR and 3D-FFE-WATS sequence was statistically significant (P<0.05), the others are statistically significant (P<0.01). The sensitivity,specificity, accuracy of diagnosising articular cartilage lesions on 3D-FFE-SPIR is 89.4%,91.7%,93.6%.the sensitivity,specificity, accuracy of diagnosising articular cartilage lesions on 3D-FFE-WATS is 90.2%, 98.8%,95.2%. the sensitivity,specificity, accuracy of diagnosising articular cartilage lesions on 3D-Balance-FFE is 81.0%,89.4%,85.6%. Conclusion: Knee cartilage imaging by MR 3D sequences can provide comprehensive and accurate articular cartilage information for clinical,3D-FFE-SPIR and 3D-FFE-WATS sequence are excellent sequences for showing knee cartilage and diagnosising articular cartilage lesions, the scanning time of 3D-FFE-WATS is shorter than 3D-FFE-SPIR and not sensitive to magnetic fields change, therebefore,3D-FFE-WATS is the best sequence for knee cartilage imaging. |
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