髌骨病变的影像学表现.pptx
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1、Normal radiographs of the knee with anteroposterior(a),lateral(b),and axial(c)biew demonstrate normal patellar position and morphology.The anteroposterior projection(a)is useful for evaluting the femur and proximal tibia,femoral and tibial plateaus.The lateral projection is useful for evaluating pat
2、ellar height,patellofemoral compartment,suprapatellar recess(SR),quadriceps tendon(QT),patellar tendon(PT).The axial view of the patella helps in assessment of the shape of the patella,note media(MF)and lateral(LF)patellar facets and median ridge(MR).Also note normal and rough anterior patellar cort
3、ex(blue arrow).,Sagittal proton density(a)and axial fat-suppressed T2-weighted(b)MR images of a normal knee.Note the low signal patellar(PT)and quadriceps(QT)tendons and the thick,homogeneous-appearing patellar cartillage(red arrows).Note the lateral and media retinacula,passive stabilizers of the p
4、atella.,In 1941,Wiberg classified patellar shape into three different morphologies:Type I(a)demonstrates roughly symmetric and equal-sized,concave medial(MF)and lateral(LF)patellar facets.Type II(b)shows a medial facet that is slightly smaller than the lateral facet and a concave lateral facet.Type
5、III(c)also shows a smaller and more vertically oriented medial patellar facet,which is associated with maltracking disorders 18.,5-year-old male with hereditary osteo-onychodysplasia(nail-patella syndrome).AP(a),later(b),and axial(c)views of the knee demonstrate complete absence of the bilateral pat
6、ellar ossification centers.,Anteroposterior and axial radiographs(a)show bilateral,well-corticated ossified fragments in the superolateral aspect of the patellas(arrows).Coronal and axial T2-weighted fat-suppressed MR image(b)show the well-corticated ossified fragment.Note the normal bone marrow sig
7、nal and cartilage across the synchondrisis,The well-corticated nature of the fragment and lack of abnormal marrow signal help to differentiate this entity from a patellar fracture.,Anteroposterior,lateral,and axial radiographs(s)show a lucent,round lesion with well-defined margins at the superolater
8、al aspect of the patella(arrows).Sagittal proton density and axial T2-weighted fat-suppressed MR images(b)show a focal subchondral osseous defect with intact-appearing overlying cartilage;the cartilage is thickened,and fills the defect.There is normal bone marrow signal and smooth,homogeneous signal
9、 of the articular cartilage.,Congenital patella alta is an anatomic risk factor for patellofemoral instability.The insall-Salvati index is the ratio of the length of the patella(PL)to the patellar tendon(PT).The normal value is between 1.0 and 1.2,with increased values indicating patella alta and de
10、creased value indicating patella baja.Lateral radiograph(a)at approximately 30 degrees of knee flxion shows a noemally placed patella,with Insall-Salvati index of 1.1.Lateral radiograph(b)of an 8-year-old male shows patella alta,with Insall-Salvati index measuring 1.8.Axial T2-weighted tubro spin ec
11、ho MR image(c)form this same patient shows finding of a lateral patellar dislocation.There is bone marrow edema of the medial aspect of the patella(arrow)and disruption of the medial patellar retinaculum(asterisk).This patient had a history of recurrent dislocations,likely due to his congenital pate
12、lla alta.,Anteroposterior(a)and lateral(b)radiographs of a 15-year-old female patient with cingenital right-sided patella baja.,Lateral radiographs of a patient one year following total knee arthroplasty demonstrates patella baja.The patellar tendon is scarred to the upper tibia(arrow).,Patella baja
13、 may also be seen in association with neuromuscular diseases.Fromtal(c)and lateral(d)radiographs in this patient with a history of polio show marked patella baja.Also nite that the bine are osteopenic and gracile and that there is a paucity of soft tissues,in keeping with the patients history of pol
14、io.,Trochlear dysplasia is among the most significant anstomic factors contributing to patellar maltracking Lateral radiograph(a)depicts one sign,the crossing sign,in which the line of the deepest aspect of the trochlear groove crosses over the antenor aspect of the femoral condyles(arrow).Sagittal
15、proton density image(b)depicts another hnding of trochlear dysplasia.The ventral trochlear prominence(vtp)has been detined as the distance between the line paralleling the ventral cortical surface of the distal femur and the most anterior point of the femoral trochlear floor.In this image is seen a
16、step-like deformity at the intertace of the anterior femoral cortex and trochiea with a vte measuring 9 mm,consistent with trochlear dysplasia.Axial T2-weighted fat-suppressed image(c)shows a congenitaly dysplastic trochlea with a markedly shallow trochiear depth(arrow),consistent with trochlear dys
17、olbsia Addisanally noted is marked asymmetry of the medial(MF)and lateral(LF)trochlear facets.A lateral to medalfemoral facet.rano ot greater than 1.75 is generally considered diagrosnc for trochlear dysplasia.In this case the ratio measures23.representing another tinding of trochlear doplasia,Troch
18、lear depth assessed on axial T2-weighted fat-suppressed images.A line is first drawn parallel to the posterior temoral condies(A).Lines drawn perpendicular to this indicate the anteroposterior dimensions of the lateral(B)and medial(C)trochlear facets and of the deepest portion of the lemoral trochle
19、a(D)Calculate trochlear depth with the equaion(BC/2)-D.Trochlear depth of 3 mm or less indicates trochlear dysplasia.image(a)shows a normal trochlear depth,image(b)shows a dysplasnc trochlea with marked flattening,The distance from the tibial tubercle to the trochilear groove is measured on axial MR
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- 髌骨 病变 影像 表现

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