Abstract
Traditionally, lymphedema is detected and described in relationship to perceived clinical risk, supported by clinical validation through physical examination. Lymphatic imaging is rendered difficult because of the unidirectional nature of this vascular system: both traditional radionuclide lymphoscintigraphy and near-infrared fluorescence lymphography, as well as magnetic resonance techniques, rely upon introduction of the imaging contrast agent into the skin by injection.
In this issue of Lymphatic Research and Biology, two articles document the utility of additional, and potentially less cumbersome, techniques that can help to refine the diagnostic evaluation of lymphedema. In the first of these, Gündüz and colleagues have chosen to prospectively investigate the complementary utility of ultrasonography in the diagnostic evaluation of breast cancer-associated lymphedema. They investigated 34 subjects with documented breast cancer-related lymphedema, utilizing correlative estimates of limb volume with the traditional mathematical extrapolation from serial measures of limb circumference.
In this way, they demonstrated a significant positive correlation between circumferential measurements and ultrasonographic quantitation of subcutaneous thickness. The ultrasonographic technique was highly sensitive with an acceptable specificity in its discernment of Grade 2 from Grade 3 disease. These observations serve to complement and validate the observations Hara and Mihara and Kim et al. both recently published in the pages of this journal.1–3
Citing the cost and lack of general availability of radionuclide and near-infrared imaging modalities, Hara and Mihara report their observations regarding lymphedema diagnosis by ultrasound. Their study includes evaluation of 28 limbs assessed preoperatively before lymphaticovenous anastomosis. Indocyanine green lymphography was utilized to validate the ultrasonographic findings. The authors observed that the sensitivity and specificity for diagnosis of lymphedema based on echography of the medial leg were 95.0% and 100.0%, respectively. The accuracy rate was 94.6%. These data appear to confirm the potential utility of ultrasonography for the diagnostic evaluation of potential lymphedema.
In a complementary approach to lymphedema diagnosis, Tanaguchi et al. have investigated the utility of estimates of limb circumference through application of three-dimensional body scanning to the problem of lower extremity lymphedema. In this study, the authors have documented. In 15 healthy women, they measured limb circumferences in the thigh and in the lower limb. The authors demonstrate that this volumetric imaging technique can detect edematous changes in the lower leg. Furthermore, they document that changes in segmental volume can be correlated to parallel measured changes in the resistance of the extracellular water component, as measured by segmental bioimpedance spectroscopy.
In sum, the available palette of imaging techniques for lymphedema is expanding. It can be envisioned that future more widespread application of these approaches will both improve early diagnosis and provide the necessary tools to evaluate current and future therapeutic interventions.