The Study Of The Sensitive MR Sequences In Articular Cartilage And Its Clinical Application

PURPOSE: To evaluate MR sequences of human cartilage and search for the most valuable sequence and explore its clinical application in the acute chondral trauma and cartilaginous tumors. MATERIAL AND METHODS: 31 patients with acute injury history and the results of arthroscopies and 7 patients with cartilaginous tumors were studied in MRI. The methods are as follows: 1. All MR images were performed from GE Signa 1.5 TMR/i scanner. The sequences included: Sagittal T1 weighted fast spin-echo (FSE-T1WI), T2 weighted fast spin-echo (FSE-T2WI),dual-echo fast spin-echo with fat-suppressed(FS-FSE-T2WI/PD),fat-saturation three-dimensional fast spoiled gradient echo ( FS-3D-T1*-FSPGR ) ,out phase T1 weighed three-dimensional fast spoiled gradient echo(UnilateralT1-Special-3D- FSPGR),T2 weighted gradient echo(GR),diffusion weighted imaging(DWI, b=300s/mm3)and Axial fat- suppressed fast spin-echo proton density(FS-FSE-PD)。 2. Given the staging diagnosis of chondral lesions , analyzed the MR appearance of injuried cartilage and subcartilaginous bone and the signal characters of cartilaginous tumors, measured the width of cartilage cap. All MR diagnosis compared with the results of arthroscopies and gross specimens. 3. The statistic methods: using SPSS 11.5 software. RESULTS: 1. The SNR of FS-FSE-T2WI,FS-FSE-PD, FS-3D-T1*-FSPGR, UnilateralT1-Special-3D- FSPGR were 5.75±0.47,51.57±2.28,43.96±5.23 and 45.00 ± 10.18. There was statistic significance between FS-FSE-T2WI and other 3 sequences. Among the latter 3 sequences, there were no statistic significance. 2. The sensitivity, specificity, accuracy, positive predictive value, negative predictive value and Kappa value of combined Sagittal and Axial FS-FSE-T2WI/PD were 91%, 99%, 97%, 98%, 94%, 0.80,respectively; 81%, 97%, 95%, 96% ,87% ,0.71 with FS-3D-T1*-FSPGR and UnilateralT1-Special-3D- FSPGR. There was significance of Kappa value between the FS-FSE-T2WI/PD and FS-3D-T1*-FSPGR. 3. The MR appearance of chondral lesions included:① cartilage thicken with abnormal signal;② osteochondral compression fracture;③ partial or full-thick defection of cartilage with or without subcartilaginous bone abnormal signal;④ abruption of chondral surface, flap-like free segment and fluid-like signal at the cartilage-bone junction; ⑤ osteochondral delamination ,broken, in situ or out of place. 4. 6 of 7 cartilaginous tumors had similar signal characters: low signal on T1WI, slightly bright signal on T2WI, brilliant high signal on FS-FSE-T2WI/PD and GR, slightly high signal on FS-3D-T1*-FSPGR and UnilateralT1-Special-3D-FSPGR, homogeneous high signal on DWI. The measurements of cartilage cap in GR sequence were closest to the gross specimens. CONCLUSION: 1. FS-FSE-T2WI/PD is the most sensitive sequence of articular cartilage lesions. 2. UnilateralT1-Special-3D-FSPGR sequence has the same diagnostic capability with FS-3D-T1*-FSPGR, higher SNR and fewer acquisition timethan FS-3D-T1*-FSPGR sequence. So UnilateralT1-Special-3D- FSPGR can take the place of FS-3D-T1*-FSPGR used in clinic completely. 3. MR can reflect the random and degree of acute cartilage trauma accurately and help clinic therapy choosing and following observation. 4. Cartilaginous tumors had specific MR appearance. Among the cartilage sensitive sequences of FS-FSE-T2WI/PD, FS-3D-T1*-FSPGR , UnilateralT1-Special-3D-FSPGR and Heavy T2 weighted GR ,the Heavy T2 weighted GR sequence is the most valuable MR sequence of diagnosis in cartilaginous tumors.