Study Of MR Diffusion Weighted Imaging Of Patella Cartilage In Osteoarthritis

PurposeTo discuss the difference in ADC values and characteristics of patella cartilagein osteoarthritis (OA) at MR DWI imaging and analyze the difference of ADC valuesbetween degraded cartilage of OA and normal cartilage and the difference in variousdegrees of OA.MethodThe cases included 23 subjects(13 mild subjects and 10 severe subjects) whichreported symptoms of patellofemoral and were diagnosed OA clinically and verified byarthroscopy. The average age was 49.4 years old which were from 34 to 69 yearsold. There were 8 men and 15 women. All cases were divided into 2 groups-mild andsevere degree by arthroscopy (gradeâ… and gradeâ…¡were mild degree,gradeâ…¢andâ…£were severe degree). Among of them there were 13 mild subjects and the others weresevere subjects. There were 15 patella cartilages in 10 normal subjects. The exclusioncriteria were history of trauma, orthopedic surgery, chronic disease requiring medicaltreatment, and joint pain or stiffness. There were 8 men and 15 women which averageage was 31.2 years old which was from 25 to 38 years old. All subjects were imagedwith routine sequnces and 3D-WATSc SE sequnce, DW- Msh- HR sequence withPhilips Achieva 3.0T MR scanner using sense-flex-m receive coil. After the imageacquisition the adjacent two layers on which the patella cartilages showed largest wereselected to represent the upper and lower layer of cartilage in every subject onworkstation. And each layer was divided into the inner part(include the mid crest) andouter part with the border of the mid crest, then the cartilage was divided into four parts. The ROI was wide as far as possible and the joint liquid was avoided to be drawninto. The signal intensities were measured at the same scan and area respectively onthe DWI imaging of different b values, and the ADC values were obtained according tothe following formula: ADC=LN(SI_low/SI_high)/(b_high-b_low). The average value of 3 ROIsin every part represented ADC value of every part. The average value of the 4 partsrepresent ADC values of the whole cartilage. Then ADC values were analysed. Thearthroscopy were preformed by two experienced doctors. The arthroscope was placedinto the articular cavity anterolaterally and anteromedially. The leg was moved tocooperate with the arthroscopy in order to explore the structure in the articular cavityorderly. The degree of cartilage degradation under arthroscopy was according to theOutbridge standard.Every ADC value was computed with "mean±standard". The datawere dealed with SAS8.1 software package.ResultsThe patella cartilage represented mild degeneration of 13 cases(6 of greadeâ… , 7 ofgradeâ…¡) and severe degeneration (gradeâ…¢) under arthroscopy. ADC value in normalsubjects was 1.53+0.16×10^-3mm²/s. In OA subjects, ADC value was 2.13±0.28×10^-3mm²/s, the latter was bigger than the former, t-test was perfprmed between them, weconcluded that t=9.49(P＜0.05). There is obvious difference statisticlly between them.ADC value is 2.01±0.26×10^-3mm²/S in mild subjects. In severe subjects, ADC valuewas 2.28±0.25×10^-3mm²/s. ADC value of mild subjects was smaller than that of severesubjectse and both were bigger than that of normal cartilages. One way analysis ofvariance (Bonferroni) was performed among of them. We discovered that there weresignificant difference statistically among of them.ConclusionThe ADC values of OA subjects were bigger than that of normal subject obviously.Morever, ADC values increased gradually with the progress of OA. The pathologicalchanges appeared before the morphologic change. MR DWI could find the earlydegeneration of cartilage by analyzing quantificationally and could be a new method of evaluating the progress of OA.