USE OF THE C-SCAN IN EVALUATION OF PERIPHERAL LYMPHEDEMA

Abstract

The C-(cutaneous)-scan constitutes a simple way to evaluate the status of the lymphaticsystem of swollen and apparently normal extremities. We have termed the procedure C-scanbecause this expression emphasizes the injection of the radiotracer into the cutis. Only onescintiscan, which takes approximately 15 minutes, is performed 3 hours after injection, incontrast to other investigative procedures including standard lymphangioscintigraphy, whichutilize multiple scannings that unnecessarily prolong the duration of the study. The C-scanmethod is semi-quantitative and distinguishes pathologic conditions of the lymphatic system bymeans of whole body scintigraphy and by measuring the radioactivity in specific regions ofinterest rather than by examining solely differences in delay of transport. Both a qualitativeimage and a quantitative assessment are thereby produced. The C-scan is performed using ageneral purpose gamma camera in line to a multiprocessor computer system. Scintiscanning isperformed 3 hours after an intracutaneous injection of 20 MBq of Tc99m nanocolloid (Solco)distally into the dorsum of the extremity. The image obtained is divided into regions of interestand the radioactivity in these regions is calculated as the percentage of the total radioactivitycounted. The C-scan is easy to perform and can be repeated if necessary every 2 days. Theeffects of various treatments of lymphedema, either non-operative or operative, can be assessedshort-term, and examples are provided. In conjunction with limb volume measurements, the Cscan gives an accurate impression of changes in the lymphedematous extremity before, during,and after treatment. Applications of this imaging technique are shown after combined“decongestive” physiotherapy, lymph-venous anastomosis, ablative (debulking) surgery,liposuction, and thermotherapy