2440. Distribution and Pattern of Edema and Resulting Tissue Swelling on MRI in the Lower Extremities of Secondary Lymphedema
Authors * Denotes Presenting Author
  1. Geunwon Kim *; Beth Israel Deaconess Medical Center
  2. Michael Adondakis; Beth Israel Deaconess Medical Center
  3. Martin Smith; Beth Israel Deaconess Medical Center
  4. Leo Tsai; Beth Israel Deaconess Medical Center
The distribution and pattern of edema of the lower extremities in patients with secondary lymphedema to surgical intervention is not well studied. Given emerging new interventions to manage lymphedema, an understanding of the pattern of edema would be important to guide surgical approaches, such as targeted debulking or direct lymphatic repair, and physical therapy. The purpose of this study is to compare the differences in the tissue thickness of the affected and unaffected lower extremity of patients diagnosed with unilateral secondary lymphedema due to surgery.

Materials and Methods:
Retrospective review of all dedicated lower extremity MRI for lymphedema on patients who were referred from a lymphedema specialty clinic between July 2017 and December 2019 was performed. Axial STIR images of the affected and unaffected thigh (10 cm from the lesser trochanter) and the calf (20 cm from tibial plateau) were analyzed by dividing the limb into four quadrants and measuring the thickest subcutaneous tissue in each quadrant. Pre-tibial subcutaneous tissue was measured at the same location as the calf by measuring the shorted distance between the skin and the superior edge of the tibia. Paired t-test was performed between the tissue thickness at each quadrant of the affected and unaffected limb.

36 patients were included (23 women and 12 men). Average age was 51.4±14.1 years, average duration of symptoms was 8.0±8.2 years, and average BMI was 28.8+6.6. There was significant difference in the thickness of the subcutaneous tissue between the unaffected and affected limb at all quadrants (p<.007 for all) except the posterolateral quadrant of the thigh (p=.94).

The edema of the lower extremity preferentially spares the posterolateral thigh area whereas the rest of the lower extremity is significantly affected in patients with unilateral secondary lymphedema. Increased awareness and knowledge of the pattern of soft tissue swelling along the lower extremities would help to optimize emerging new targeted therapies for lymphedema.