Short- and long-term reproducibility of peripheral superficial vein depth and diameter measurements using ultrasound imaging

Background: Ultrasound imaging is used for diagnosis, treatment, and blood vessel visualization during venous catheter placement. However, various physiological factors (e.g., body temperature and exercise) influence vein diameters, which are expected to exhibit daily or diurnal fluctuations. Therefore, this study aimed to determine the intraday (short-term) and interday (long-term) reproducibility of repeated measurements of the depth and diameter of peripheral superficial veins. Methods: Twenty-three healthy young women (mean age, 21.7 ± 0.8 years) participated in the study to examine the short- and long-term reproducibility of the depth and diameter of the cutaneous vein in the left elbow fossa acquired by ultrasound imaging. Short-term measurement intervals were 10 s, and the probe was released from the skin for each acquisition, which was repeated five consecutive times. Long-term measurements were performed at the same time on the next day following the same procedure. The acquired images were analyzed for vein depth and diameter using ImageJ software. The intraclass correlation coefficient (ICC) was calculated to determine the short- and long-term reproducibility of the measurements. The relationship between the venous depth and venous diameter intra-individual variation was analyzed, as well as the influence of body composition (body fat and muscle mass) on the venous diameter and depth. Results: For vein depth measurements, the short- and long-term ICCs were 0.94–0.96 and 0.88, respectively. For the vein diameter, the short- and long-term ICCs were 0.94–0.97 and 0.67, respectively. The short-term ICCs for both vein depth and diameter exceeded 0.9, indicating that the ultrasound vascular measurement was sufficiently reliable. However, long-term reproducibility was slightly lower, especially for the vein diameter. No correlation was found between the intra-individual variation of the vein diameter and vein depth. Although the vein diameter and body fat mass uncorrelated, the vein depth and body fat mass significantly correlated (r = 0.675, 95% confidence interval = 0.281–0.830). Conclusions: The long-term reproducibility of vein diameters was somewhat lower than that of the short-term reproducibility. This could be attributed to fluctuations in the physiological state of the participant rather than to the instability of the measurement. Therefore, ultrasound measurement of the peripheral superficial vein is sufficiently reliable.