Researchers may have documented in vivo rouleaux formation occurring within 5 minutes of smartphone exposure using ultrasonography, according to a new study.
In the study, published in Frontiers in Cardiovascular Medicine, the researchers demonstrated erythrocyte aggregation in the popliteal vein following brief contact with an active smartphone. The observation was made using real-time ultrasonography in a controlled setting.
"Preexposure longitudinal sonographic images demonstrate a normal anechoic lumen to the popliteal vein. Images obtained 5 min after direct skin exposure to the smartphone demonstrate a dramatic change in the acoustic appearance of the vessel," the study authors reported. "The interior of the vessel became coarsely hypoechoic with sluggish flow seen in real-time images, a typical sonographic appearance for rouleaux formation" they added.
Using a GE Logic E10 ultrasound machine with an L2-9 linear probe, the researchers imaged a 62-year-old healthy female volunteer's popliteal fossa prior to and following 5-minute exposures to an iPhone XR. The protocol was repeated three times over a 2-month period. During the final session, they observed rouleaux formation in both lower extremities despite unilateral exposure. The changes occurred independently of biochemical alterations.
"Under normal circumstances, erythrocytes have a negative surface charge (zeta-potential), which causes the cells to repel each other from over a distance of 20 nm," the study authors explained. "The presence of rouleaux formation on ultrasound indicates these surface charges have weakened," they continued.
The methodology addressed previous study limitations by providing real-time, in vivo documentation without extraction artifacts. "Sonography is a useful, noninvasive tool affording dynamic in vivo assessment of RBC aggregation and altered flow characteristics without potential technical errors prone to dark field microscopy," the study authors wrote.
While rouleaux formation is typically transient, the study noted potential implications in patients with preexisting conditions. "Morbidity is determined by the patient's underlying health status. Ischemic heart disease, diabetes, prethrombotic states, cancer, peripheral vascular disease, retinopathy, and cerebrovascular insufficiency are among the risk factors that will increase the morbidity associated with the development of rouleaux," the study authors concluded.
The researchers identified the study's limitation as a single-subject investigation and recommended larger population studies to determine prevalence and identify specific radiofrequency parameters associated with rouleaux formation.
