case_images: PMC2718189_01
case_images: A 34-year-old man with chronic renal insufficiency and pain in both knees.. A. Lateral radiograph of the left knee shows fine calcific opacities (open arrows) at the superior aspect of the patella.. B. Longitudinal US of the right knee reveals discontinuity of the normal fibrillar patterns (arrows) and arc-like calcifications (open arrows), with posterior shadowing at the proximal insertion site of the patellar tendon. P= patella.. C. T1-weighted sagittal MR image of the left knee shows focal thickening with inhomogeneous increased signal intensity (arrows) at the insertion site of the quadriceps tendon.. D. T2-weighted sagittal MR image of the left knee shows a slight increase in signal intensity at the insertion site of the quadriceps tendon (arrows) and abnormal increased signal intensity within the popliteus muscle (open arrow).. E. T1-weighted coronal MR image shows medullary streaks of low signal in the metaphyses and diaphyses of the distal femur and proximal tibia. The epiphysis of the femur and tibia were relatively spared.. F. Unenhanced CT scan shows irregularly thickened trabeculae (arrows) in the bone marrow of the distal femora. Also note the presence of joint effusion (open arrows) in the suprapatellar bursae of both knees.
case_images: kjr-1-172-g001.jpg
case_images: PMC2718189_01_kjr-1-172-g001.jpg
case_images: F1
case_images: Plain radiographs of both knee joints showed arterial calcification of pipe-stem appearance in both lower legs, and fine calcifications in the suprapatellar area of the left knee (Fig. 1A) and the infrapatellar area of the right. In the right knee, there was also complete discontinuity of this tendon (Fig. 1B). Sagittal T1-weighted MR imaging (TR/TE = 600 ms/35 ms) of the left knee demonstrated obliteration of the normal laminated appearance and focal thickening, with inhomogeneously increased signal intensity from the insertion site of the quadriceps tendon to the base of the patella (Fig. 1C). Sagittal T2-weighted MR imaging (TR /TE = 2500 ms/80 ms) revealed slightly increased signal intensity in the thickened area, and T2-weighted MRI also showed an area of abnormal increased signal intensity within the popliteus muscle of the left knee (Fig. 1D). T1- and T2-weighted MRI also demonstrated multiple vertical lines (medullary streaks) of low signal intensity in the metaphyses and diaphyses of the distal femur and proximal tibia. The lines were rough and irregular (Fig. 1E). Unenhanced scans showed coarse and thickened trabeculae in the metaphyses of both distal femora, with a moderate amount of joint effusion in the suprapatellar bursae (Fig. 1F).