| Part1 Patellar tilt evaluated by dynamic CT Aim:To explore the clinical significance and comparison of different method about evacuating patellar tilt by dynamic CT scanning. Material and methods:40 cases were diagnosed as patellar tilt(only one knee) by clinical examination. These patients were performed by dynamic CT scanning. Philips 64 slice spiral C T was used in this process. Damaged knee joints of each patient were scanned in bending their knees at 20 and 30 angle by CT volume scanning. The images obtained were introduced into the workstation for processing. The maximum level of patella image measurement was selected and analyzed. Patellar tilt angle(PTA)and lateral patellofemoral angle(LPFA), the most common methods, were used to evaluate patellar tilt respectively according to the related literature evaluation standard. Parameter values were expressed in degree. The following parameters were needed to statistical comparison:(1)The positive rate of patellar tilt was evaluated from PTA and LPFA in bending knees at the angle of 20 and 30.(2)The two group of parameters from PTA in bending knees at the angle of 20 and 30.(3)The two group of parameters from LPFA in bending knees at the angle of 20 and 30. Results:(1)There is difference about positive rate of patellar tilt measured from PTA and LPFA in bending knees at the angle of 20 and 30, the positive rate of PTA is better than the positive rate of LPFA.(2)There is difference about parameter values measured from PTA in different flexion(P<0.05). Compare with bending knees at the angle of 30, the measurement of PTA is more accurate in bending knees at the angle of 20.(3)There is difference about parameter values measured from LPFA in different flexion(P<0.05),Compare with bending knees at the angle of 30, the measurement of LPFA is more accurate in bending knees at the angle of 20. Conclusion:There is higher image resolution in the evaluation of the patellar tilt by dynamic CT. Compare with bending knees at the angle of 30, the measurement of PTA and LPFA is more accurate in bending knees at the angle of 20. And the positive rate of PTA is better than the positive rate of LPFA. This is of practical significance in the evaluation of patellar tilt accuracy rate and selection of measurement method to clinical doctor.Part2 Correlation study between patellar tilt and T2 mapping value of Patellar cartilage Aim:Correlation study on the PTA parameter and T2 mapping value of patellar cartilage from patellar tilt patients(29 cases) diagnosed by dynamic CT at the angle of 20°. To explore the reference value of T2 to analyze ingredient change of patellar cartilage, and clinical diagnostic value of T2 mapping image technology to early-stage occult cartilage injury from patellar tilt patients.Material and methods:29 cases from part 1 were diagnosed as patellar tilt by dynamic CT at the angle of 20°. These patients were performed by dynamic CT scanning. American GE company 3.0T superconducting magnetic resonance imaging and 8 channel high resolution knee joint coils were used in this process. The examination position of every patient was supine position, knee joint relaxed freely, Toes rotated to outside slightly. The MRI images of patellar transverse section were acquired under the standard sagittal positioning piece of knee joint. Conventional T2W-fat suppressed FSE sequences were selected as scanning sequence. After that, T2 mapping sequences were used to scan. Finally, the images obtained were introduced into the MRI workstation and processed after T2 mapping. Thus, pseudo color images of T2 mapping were produced. All the data was collected from the largest level of axial patella on pseudo color images of T2 mapping. In this study, the ipsilateral patellar cartilage of patellar tilt patients was divided into 5 measurement zones from inside to outside. They are:(1) medial area;(2) 1/2 medial area;(3) middle area;(4) 1/2 regiones lateralis;(5) regiones lateralis(see picture 2-1). Patellar cartilage T2 value was measured in 5 measurement area, every area was measured at least 3 times. Finally, the mean value was obtained as final standard. These data need to be analyzed by statistical method: PTA parameter obtained by dynamic CT at the angle of 20° and patellar cartilage T2 value from 5 measurement zones obtained by T2 mapping were performed correlation study. Results:(1) There is no significant correlation between PTA parameter and patellar cartilage T2 value from medial area(r=0.223,P>0.05);(2)There is no significant correlation between PTA parameter and patellar cartilage T2 value from 1/2 medial area(r=0.214,P>0.05);(3)There is no significant correlation between PTA parameter and patellar cartilage T2 value from middle area(r=0.225,P>0.05);(4)There is significant correlation between PTA parameter and patellar cartilage T2 value from 1/2 regiones lateralis(r=0.763,P<0.05);(5)There is significant correlation between PTA parameter and patellar cartilage T2 value from regiones lateralis(r=0.636,P<0.05)。 Conclusion:There is significant correlation between PTA parameter and patellar cartilage T2 value from regiones lateralis and 1/2 regiones lateralis;There is no significant correlation between PTA parameter and patellar cartilage T2 value from medial area,1/2 medial area and middle area. There is significant reference value of T2 to analyze ingredient change of patellar cartilage. And there is significant clinical diagnostic value of T2 mapping image technology to early-stage occult cartilage injury from patellar tilt patients. |
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