A Scintigraphic Method for Quantitation of Lymphatic Function in Arm Lymphedema

Svend Hvidsten, Navid M. Toyserkani, Jens A. Sørensen, Poul F. Høilund-Carlsen, and Jane A. Simonsen. Lymphatic Research and Biology, 2018

Click to read the abstract

A Scintigraphic Method for Quantitation of Lymphatic Function in Arm Lymphedema

Svend Hvidsten, Navid M. Toyserkani, Jens A. Sørensen, Poul F. Høilund-Carlsen, and Jane A. Simonsen. Lymphatic Research and Biology, 2018

Background: Lymphoscintigraphy is commonly used to assess breast cancer-related lymphedema. However, a reliable quantitative method that clearly distinguishes normal lymphatic function from lymphedema is desired. We propose a quantitative method based upon the physiological mean transit time (MTT) measure of lymph fluid passing through the arm.

Methods and Results: Eleven patients, aged 34–68 years, with unilateral arm lymphedema following breast cancer treatment underwent simultaneous bilateral lymphoscintigraphy using intradermal injection of 99mTclabeled human serum albumin (HSA). Imaging was performed at 30–45 minute intervals for 5 hours. Time activity curves from each injection site and each arm region were recorded. The input into the arm region was obtained as the (minus) time derivative of the injection site activity curve. In the proposed model the arm activity curve was considered to arise from the convolution of the retention function and the input function. The retention function was obtained by fitting the calculated arm activity curve to the measured arm activity curve. The MTT of activity passing through the arm was calculated as the time integral of the resulting retention function. All measured time activity curves were well described by the model. The MTT of the lymphedema arm (mean 60.1 minutes, range 22–105 minutes) was markedly different from that of the contralateral normal arm (mean 5.4 minutes, range 1.2–8.7 minutes), p<0.0001.

Conclusion: The proposed model showed great similarity with measured time activity curves and was capable of quantitatively distinguishing lymphatic function of the lymphedema arm from that of the normal arm in terms of calculated MTT.

Main findings

  • The suggested model showed a significantly longer mean transit time (MTT) in all 11 lymphedema arms than in the contralateral normal arms; MTT was on average 15 (3–50) times longer in the lymphedema arm compared to the normal arm.
  • The authors suggest the described method as a tool to objectively evaluate lymphedema in BCRL and maybe also to evaluate the risk of developing arm lymphedema. Furthermore, the method might prove just as beneficial in diagnosing and evaluation of lymphedema of the lower extremity.
  • The effect of exercise wasn’t investigated. Exercise might promote a relatively shorter MTT in the normal arm compared to MTT in the lymphedema arm and, therefore, promote distinguishing lymphedema and normal arm. Exercise might help shortening the acquisition time and provide knowledge regarding lymphatic flow reserve, a quantity similar to myocardial blood flow reserve measured by myocardial rest– stress perfusion imaging.
  • The proposed novel approach was capable of describing the measured time activity curves of the arm regions and provided a quantitative MTT measure of lymphatic fluid through the arm that clearly distinguished the lymphedema arm from the contralateral normal arm in women suffering from BCRL.
  • The method may have promising clinical perspectives, not only with regard to grading the degree of lymphedema but also possibly for evaluating the effect of new treatment measures and perhaps also for preoperative assessment of which patients are most at risk of developing lymphoedema postoperatively.