The Preliminary Assessment Of T2 Mapping And SWI Functional MRI For The Patients Of Hemophilic Arthropathy

Background and goalHemophilic arthropathy( HA) is the most common complication of hemophilia. The knee joint is a load-bearing joint, with a high risk of bleeding, Recurrent bleeding can result in joint deformity, seriously affecting the patient’s quality of life. Magnetic resonance imaging(MRI) is one of the most effective tools for detecting HA. The conventional sequences of MRI are sensitive for the diagnosis of advanced arthropathy, but difficult to find early articular cartilage lesions and minor bleeding in the joints.Functional MRI, such as T2 mapping image can detect cartilage lesions at a molecular and biochemical level. T2 mapping reflects the interaction between water molecules and the interaction between water molecules and surrounding macro-molecules of cartilage,reflecting the change of collagen composition and water content in cartilage. Currently T2 mapping image are commonly used in the study of osteoarthritis and other degenerative diseases of joints,but less seen in the study of HA. SWI sequence is highly sensitive to hemosiderin, iron deposition or other hemorrhagic lesions, and may supply more information for the diagnosis of hemorrhagic diseases. SWI commonly used in the diagnosis and research of cerebral hemorrhage disease, but rarely used in the research of muscular skeletal system in the literature.The main purpose of this research are mainly in the following two aspects:(1) Further explore the changes of early cartilage components in the early stage of HA by the method of T2 mapping imaging, and to preliminary evaluate the clinical value of the sequence for the patients with HA.(2) to investigate the ability of SWI sequence in the detection of micro-hemorrhage and hemosiderin in the joints, and the diagnosis value for HA. MethodThere ware 50 cases of hemophilia patients(78 knees) and 10 volunteers(18 knees) inrolled in our study. All the patients had joint bleeding experience and different bleeding times. Conventional sequences(T1WI, T2 WI, FS-PDWI), 3D-FS-SPGR, T2 mapping image and SWI sequence ware performed in 3.0T MRI. According to magnetic resonance cartilage grading standards of the International Cartilage Repair Association(ICRS), the study subjects were divided into control group(volunteers, grade 0) and experimental group. The experimental group were further divided into group A(grade 0), group B(grade I-II) and group C(grade III-IV). The control group, experimental group A and group B were inrolled in the study of T2 mapping sequence research. All the experimental group were inrolled in the research of SWI sequence. The T2 mapping image is post-processed in order to obtain the pseudo color image of cartilage. The region of interesting(ROI) of cartilage ware divided into 6 areas, including femoral condyle, patella, lateral femoral condyle, lateral tibia condyle, medial femuoral condyle and the medial tibia condyle, in which the slice of most thick cartilage layer was selected to measure T2 value. The joint numbers of hemorrhage and hemosiderin on conventional sequences and SWI sequences were recored. The differences of T2 values between the experimental group and the control group and intra-experimental groups were analyzed with single factor variance analysis. P <0.05 for the difference was statistically significant. The numbers of joint hemorrhage and hemosiderosis detected on conventional sequences and SWI sequence were expressed with percentage. Result1. The difference of T2 values of total and each ROI area cartilage were statistically significant between the control group and the experimental group, the control group and the experimental group A, the experimental group A and B(p<0.05), Except for only one area of medial tibial condyle between control group and the experimental group(p=0.09).2.There were 61 joints with hemorrhage and hemosiderin deposition(61/78, 78.21%) detected by conventional sequences, and 73 joints with hemorrhage and hemosiderin deposition(73/78, 93.59%) by SWI sequences. Twelve joints with hemosiderin deposition(12/78、15.38%) only seen on SWI sequence. Conclusion1. T2 mapping imaging, as one of the MRI functional imaging, is sensitive to the changes of early cartilage components in the early stage of HA, hinting that T2 mapping imaging may be used as a tool to diagnose the cartilage disease in the early stage of HA.2. SWI is better to find more early joint micro-hemorrhage and more hemosiderin deposition than conventional MRI.