Reply: Establishing a Standard Method for Screening Lymphatic Ultrasound in Lymphedema Patients

We thank Kukreja-Pandey et al1 for their thoughtful and constructive commentary on our article. We appreciate their recognition of the challenges inherent in lymphatic ultrasound and their emphasis on the nuanced nature of differentiating lymphatic vessels from small-caliber venous structures. We fully agree that lymphatic ultrasound is operator-dependent and that experience, probe handling, and scanner settings significantly influence image interpretation. We would like to clarify that the primary aim of our study was not to propose a definitive diagnostic or severity-grading system for lymphedema. Rather, our objective was to establish a standardized, time-efficient screening method using widely available ultrasound equipment.2 At present, one of the major barriers to the broader adoption of lymphatic ultrasound is that many clinicians—particularly beginners—do not know where to start scanning. Without a simple and reproducible entry framework, lymphatic ultrasound can seem inaccessible, and clinicians may hesitate to attempt lymphatic visualization altogether. Our protocol was therefore intentionally designed as a pragmatic starting point to lower this barrier and promote wider participation. Although lymphatic ultrasound may seem challenging at the initial stage, our experience suggests that visibility and interpretability improve substantially with training and repetition. In our institution, lymphatic ultrasound has been successfully adopted by lymphedema therapists, nurses, vascular surgeons, and plastic surgeons, leading to broader use and improved multidisciplinary communication. As familiarity increases, clinicians are able to identify lymphatic structures more consistently, which in turn enhances clinical decision-making and overall quality of care. We believe that this learnability is an important but often underappreciated aspect of lymphatic ultrasound and further supports the need for a standardized screening framework. The D-CUPS criteria were developed as a composite heuristic rather than as isolated diagnostic markers. As correctly pointed out by the authors, individual ultrasound features such as Doppler signal or compressibility can be influenced by tissue conditions, probe pressure, and scanner settings. For this reason, we did not intend for any single component of D-CUPS to be interpreted in isolation. Instead, we emphasized pattern recognition across multiple features—particularly anatomical location relative to superficial fascia and venous structures—to support consistent screening and interoperator communication. This approach was designed to facilitate training and standardization, rather than to replace expert judgment or comprehensive diagnostic evaluation. Regarding the proposed cutoff value for lymphatic ectasia, we agree that further validation is essential. Histopathologic classification of lymphatic degeneration cannot be directly translated to ultrasound imaging, and correlation with intraoperative and histological findings remains an important future goal. However, we would like to add that, across multiple independent investigations currently underway in our group, the cutoff value for lymphatic dilation on lymphatic ultrasound has consistently converged around 0.25 mm. Although the biological explanation for this reproducibility remains to be fully elucidated, it is noteworthy that this value repeatedly emerges despite differences in study design and patient cohorts. Taken together, we believe that 0.25 mm may represent a meaningful threshold for ultrasound-based screening, even as further validation studies are ongoing. Importantly, this cutoff was not intended to represent a universal diagnostic boundary, but rather a pragmatic reference point to support consistency in screening and communication. With respect to the predefined 4 scanning points, we would like to emphasize the current dissemination phase of lymphatic ultrasound. These points were selected because they are anatomically consistent, relatively easy to identify, and well suited as an initial reference for beginners. In healthy individuals, these 4 points are generally sufficient for identifying lymphatic vessels. In contrast, in patients with lymphedema, it is not uncommon for lymphatic vessels at these locations to already exhibit sclerosis or advanced degeneration. In such cases, lymphatic vessels are frequently observed in more lateral or alternative locations, a phenomenon that has also been reported by others. Accordingly, we do not advocate limiting evaluation to these 4 points in patients with established lymphedema. Rather, the proposed points serve as a standardized starting reference from which more extensive and individualized scanning can be expanded when indicated. We also appreciate the authors’ emphasis on lymph node assessment. Coincidentally, we share a growing interest in the role of lymph node morphology in lymphatic ultrasound and agree that integrating nodal and lymphatic findings may further advance our understanding of lymphatic dysfunction. Although lymph node evaluation was beyond the scope of the present screening-focused study, this represents an important direction for future investigation and may complement vessel-based assessment. In summary, our screening-oriented protocol was intentionally designed to prioritize simplicity, reproducibility, and accessibility, particularly in settings where ultra–high-frequency ultrasound systems or advanced contrast techniques may not be readily available. We believe that defining a clear and reproducible starting framework is a necessary first step toward broader adoption, upon which more advanced, experience-based assessments can be built. We welcome continued dialogue and collaborative validation across institutions and hope that this exchange contributes to the ongoing refinement of lymphatic ultrasound methodology. DISCLOSURE The authors have no financial interest to declare in relation to the content of this article.