Orthopediac 3-Dimensional Imaging of the Knee

by Janice Cook-Granroth and Stuart Weinstein, M.D.





Patient History



The patient has T.A.R. (thrombocytopenia absent radius) Syndrome. The deformity consists of significant varus of their left knee with the tibia rotating around the medial femoral condyle as its axis as opposed to both femoral condyles. When the patient flexes their knee from their starting postion, which is about a 40 degree flexion contracture, the tibia rotates around the medial condyle and thus angles abnormally inward.





Patient Scan Protocol


The patient was scanned on the Tobisha Xpress/XS helical CT scanner with the knee held in three positions of full extension, half flexion, and full flexion. The data was scanned with 5 mm thick slices that were reconstructed at 2.5 mm intervals. VIDA's shaded surface display of each scan was made and then slices of each data set were merge together to form a movie of the knee's flexion.





Movies and Images of the patient's knee.


Volume rendering of knee flexion .

Volume rendering of knee flexion (40 degree rotation).(mpeg movie)



Surface rendering of knee flexion.

Surface rendering of knee flexion (40 degree rotation). (mpeg movie)

Surface rendering of knee motion presented from four angles. (mpeg movie)

Surface rendering of the left lateral view of the knee. (mpeg movie)


Surface rendering of the forward view of the knee. (mpeg movie)


Surface rendering of the right lateral view of the knee. (mpeg movie)


Surface rendering of the back view of the knee. (mpeg movie)



Helical Transverse CT data sets

One of the original data sets with the leg at full extension. (mpeg movie.)

One of the original data sets with the leg at half flexion. (mpeg movie.)

One of the original data sets with the leg at full flexion. (mpeg movie.)



Helical Sagittal CT data sets

One of the original data sets with the leg at full extension. (mpeg movie.)

One of the original data sets with the leg at half flexion. (mpeg movie.)

One of the original data sets with the leg at full flexion. (mpeg movie.)





©1994-99 Division of Physiologic Imaging, Dept. of Radiology, Univ. of Iowa


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