Portable infrared imaging for longitudinal limb volume monitoring in patients with lymphatic filariasis

• Published in: PLoS neglected tropical diseases Vol. 13; no. 10; p. e0007762
• Main Authors: Zhou, Celia, Yahathugoda, Channa, De Silva, Lalindi, Rathnapala, Upeksha, Owen, Grant, Weerasooriya, Mirani, Rao, Ramakrishna U, Weil, Gary J, Budge, Philip J
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01-10-2019; Public Library of Science (PLoS)
• Subjects: Adult; Adults; Aged; Biology and Life Sciences; Care and treatment; Clinical trials; Coefficient of variation; Computer and Information Sciences; Disabilities; Disease prevention; Elephantiasis, Filarial - diagnostic imaging; Extremities - diagnostic imaging; Extremities - pathology; Female; Filariasis; Health aspects; Health Personnel - education; Humans; Hygiene; Imaging systems; Imaging techniques; Imaging, Three-Dimensional - methods; Infectious diseases; Infrared imaging; Infrared imaging systems; Infrared Rays; Leg; Leg - diagnostic imaging; Legs; Lymphedema; Lymphedema - diagnostic imaging; Male; Medical imaging; Medical personnel; Medical research; Medical schools; Medicine; Medicine and Health Sciences; Middle Aged; Morbidity; Patient monitoring equipment; Patients; People and places; Reproduction (copying); Sri Lanka; Systematic review; Time of use; Training; Tropical diseases; Vector-borne diseases; Volume; Workers; Sri Lanka; United States > US; Missouri; India
• ISSN: 1935-2735; 1935-2727; 1935-2735
• DOI: 10.1371/journal.pntd.0007762

The Global Programme to Eliminate Lymphatic Filariasis (LF) emphasizes hygiene, exercise, and other measures to reduce morbidity and disability related to LF. We recently reported that a portable, three-dimensional, infrared imaging system (3DIS) provides accurate limb volume measurements in patients with filarial lymphedema. To assess the practical utility of repeated 3DIS measurements for longitudinal lymphedema management, we examined intraday and day-to-day leg volume changes in adults with filarial lymphedema in southern Sri Lanka.
We assessed 41 participants with lower extremity lymphedema (stages 1-6) in their homes in the mornings (6:00-9:00 AM) and afternoons (2:00-6:00 PM) of three days within one calendar week. Two examiners performed replicate 3DIS volume measurements at each visit. Median coefficient of variation among replicate volume measurements was 1.7% (IQR 1.1% - 2.3%) for left legs and 2.2% (IQR 1.6% - 2.8%) for right legs. Median intraday volume increase was 3.0%. Range among daily volume measurements tended to be lower for afternoon measurements (median 2.25%, IQR 1.4%- 5.4%) than for morning measurements (median 3.0%, IQR 1.4% - 8.4%).
Limb volume measurements by 3DIS are accurate and reproducible, and this technique is feasible for use in patients' homes. We have developed practical suggestions for optimal outcomes with 3DIS. Duplicate measurements should be performed and repeat assessments should be done at approximately the same time of day to minimize bias. Duplicate measures that vary by more than 8% should prompt review of scanning technique with a repeat measurement. With proper training and attention to technique, 3DIS can be a valuable tool for healthcare workers who work with lymphedema patients.