Summary

Introduction: Measurement procedures for determination of leg volumes objectify the success of treatments and are used in clinical trials. Water plethysmography is still considered to be gold standard in leg volumetry. Patients and methods: This prospective study compares water plethysmography with „Venotrain Image 3D“, which is a non-contact optical method to determine leg volume, in a collective of 21 pregnant women within the age of 27 to 42 years (mean 33.4±4.4 years). At date of enrolment of the study women were in their 12. to 28. week of pregnancy. Leg volumes were measured with water plethysmography and „Venotrain Image 3D“ prospectively over 16 weeks with monthly follow-ups and a final measurement 3 months postpartum. Following compartments of the legs are measured by the respective methods: water plethysmography: Foot and lower leg until the level of 28cm above the sole of the foot; „Image 3D“: from a distal point in the malleolar region (defined by a special compression stocking) up to the knee joint gap, excluding the volume of the foot. Results : Due to the different compartments measured by the respective methods, the determined absolute lower leg volume is suitable to only a limited extent for comparison. Considering the time dependend change of volume there is a calculated correlation of both methods of r=0.78, p<0.001. In Bland-and-Altman-illustration there are no systematical deviations visible considering the time dependend change of volume. The influencing factor „length of lower leg“ shows a strong correlation to the difference of the values of both methods. Conclusion : The method of „Image 3D“ for measuring lower leg volumes correlates well with the results of water plethysmography concerning relative and absolute lower leg volumes. Considering absolute lower leg volumes, there is a systematical deviation in big volumes. The length of the lower leg seems to be the pivotal influencing factor. Both methods measure different compartments of the lower leg, so it depends on the question which method should be preferred.