II. Imaging in Phlebology and Lymphology

Abstract

Chieh-Han John Tzou^{1, 2, 3}, Aaron Metz¹, Balázs Mohos^{4, 5}, Brigitte Obermayer^{3, 6}, Stefanos Tsallas^{1, 7}, Reinhard Kaufmann⁸, René Haegerling⁹, Manuel Cornely¹⁰

¹Department of Plastic and Reconstructive Surgery, Department of Surgery, Hospital of the Divine Savior, Vienna, Austria

²Faculty of Medicine, Sigmund Freud University Vienna, Austria

³TZOU MEDICAL., Lymphology Center, Vienna, Austria

⁴Heart and Vascular Centre, Faculty of Medicine, Semmelweis University, Budapest, Hungary

⁵Plastic and Reconstructive Surgery, Surgical Center, Csonloky Ferenc Hospital, Veszprem, Hungary

⁶Obesity and Metabolic Surgery, Obesity Centre, Hospital of the Divine Savior, Vienna, Austria

⁷Department of Plastic and Reconstructive Surgery, Athens General State Hospital, Athens, Greece

⁸Interventional Radiology, Department of Radiology, University Hospital Salzburg, Austria

⁹Charité-Universitätsmedizin, Berlin, Institute for Medical and Human Genetics, Berlin, Germany

¹⁰LY.SEARCH gGmbH, Duesseldorf, Germany

The second session of the 5^th International Long Night of Lymphology Symposium is about the imaging modalities in phlebology and lymphology. Imaging supports the diagnosis of clinical symptoms and is an essential tool for therapy planning.

The ultrasound workshop led by Aaron Metz, Balázs Mohos, Brigitte Obermayer and Stefanos Tsallas demonstrates the application of duplex sonography in venous diagnostics using patient cases and shows how high-resolution ultrasound (UHFUS) can enhance lymphatic evaluations, particularly in preoperative settings. Participants of this workshop will learn how to integrate these advanced ultrasound techniques into their diagnostic and surgical planning to improve diagnostic accuracy and achieve better treatment outcomes in everyday practice. Furthermore, the current data show minor non-statistically significant differences in lymph vessel size between ultrasonography scans performed immediately after removal of compression therapy and those performed after at least 12 hours without compression therapy.

Balázs Mohos presents the details of various imaging modalities, such as lymphoscintigraphy, near-infrared fluorescent imaging, ultrasonography, magnetic resonance lymphangiography, bio-impedance spectroscopy, laser tomography and photoacoustic imaging. These advanced technologies yield specific information to facilitate proper patient-, lymph vessel-, and donor-site selection, which are prerequisites for successful lymphatic surgery.

With technological advances and growing recognition of lymphatic disorders, Reinhard Kaufmann reports the significant usage of MR and conventional lymphangiography in interventional radiology. Recent studies show standardisation in lymphangiography protocols and therapeutic indications for lymphatic interventions. Indications for lymphangiography shall be evaluated on an ongoing, case-by-case basis, involving multidisciplinary input and consideration of local resources. MR lymphangiography offers an excellent approach for most diagnostic purposes, while conventional lymphangiography serves as a potential “theranostic” tool, especially in managing lymphatic leaks and malformations.

Fast and accurate histopathological analysis of biopsied tissues or surgical specimens is essential for histopathological analysis and subsequent diagnosis in lymphology. However, the 2-dimensional slide-based histopathological analysis needs to sufficiently represent tissue structures and molecular targets, which aggravates an accurate and spatial analysis of the tissue. René Haegerling presents an innovative approach for 3D-histopathology, which allows non-destructive volumetric light-sheet microscopy for slide-free histological imaging of a whole tissue sample, volumetric analysis of immune cells or vessels, spatial analysis of cells and cell distribution relevant to interpret the vascular microenvironment. This innovative, sophisticated, and detailed diagnostic technology has the potential to become the new gold standard in histopathological analysis.

Number: 8

Workshop: Ultrasound in phlebology and lymphology

Aaron Antaeus Metz¹, Balázs Mohos^{2, 3}, Brigitte Obermayer^{4, 5}

¹Department of Plastic and Reconstructive Surgery, Hospital of the Divine Savior, Vienna, Austria

²Heart and Vascular Centre, Faculty of Medicine, Semmelweis University, Budapest, Hungary

³Department of Plastic and Reconstructive Surgery, Surgical Center, Csonloky Ferenc Hospital, Veszprem, Hungary

⁴Obesity and Metabolic Surgery, Obesity Centre, Hospital of the Divine Savior, Vienna, Austria

⁵TZOU MEDICAL., Lymphology Center, Vienna, Austria

In venous medicine, ultrasound is the most commonly used diagnostic tool, with duplex sonography playing a key role in assessing the venous system. It provides a detailed view of varicose veins, valve insufficiencies, and thromboses, making it essential for determining surgical indications and planning interventions.

In lymphology, lymphedema is usually diagnosed through patient history, inspection, and palpation. However, ultrasound helps in confirming the presence of interstitial fluid and differentiating localized swellings, while also assisting in the visualization of lymph nodes and vessels.

An important advancement in ultrasound technology is the introduction of high-resolution ultrasound (UHFUS), which significantly enhances preoperative planning, especially in cases involving lymphatic structures. While indocyanine green (ICG) imaging is often used to visualize lymphatic vessels, it may not always capture smaller or deeper structures. UHFUS fills this gap by providing highly detailed images, which allows for more precise surgical planning. For instance, when ICG fails to visualize deeper lymphatic vessels, UHFUS enables more accurate targeting, leading to improved surgical approaches.

This workshop will demonstrate the application of duplex sonography in venous diagnostics using patient cases and show how UHFUS can enhance lymphatic evaluations, particularly in preoperative settings. Participants will learn how to integrate these advanced ultrasound techniques into their diagnostic and surgical planning to improve diagnostic accuracy and achieve better treatment outcomes in everyday practice.

Number: 8a

Preoperative CGT Influence on Lymphatic Imaging with UHF Ultrasound

Aaron Antaeus Metz¹, Stefanos Tsallas^{1, 2}, Chieh-Han John Tzou^{1, 3, 4}

¹Department of Plastic and Reconstructive Surgery, Hospital of the Divine Savior, Vienna, Austria

²Department of Plastic and Reconstructive Surgery, Athens General State Hospital, Athen, Greece

³Faculty of Medicine, Sigmund Freud University, Vienna, Austria

⁴TZOU MEDICAL., Lymphology Center, Vienna, Austria

Introduction: Accurate lymphatic mapping is essential for effective lymphaticovenous anastomosis (LVA). Our center combines indocyanine green (ICG) lymphangiography and ultra-high frequency (UHF) ultrasound to visualize lymphatics, especially those deeper than the dermis that may not be captured by ICG alone due to fibrosis. To optimize imaging, compression garment use is paused 12 hours before the ultrasound, based on the hypothesis that this pause allows lymphatic vessels to expand, making them easier to detect. This study assesses the impact of compression garments, used as part of complete decongestive therapy (CDT), on lymphatic vessel imaging.

Materials and Methods: Patients undergo two imaging sessions: an initial preoperative scan and a second scan on the day of surgery, with compression garments (CGT) applied between sessions. Preliminary data from 7 patients were analyzed, using the same UHF ultrasound machine for all scans. Initial scans measured the epidermis, dermis, veins, and lymphatics, including diameters and interstitial distances after at least 12 hours of discontinuation of CGT. The second scan followed the same protocol, with measurements taken immediately after CGT removal. Identifying and replicating exact ultrasound cross-sections was essential for comparison.

Results: Preliminary data from 7 patients show no significant differences in lymphatic vessel size between scans taken immediately after CGT removal and those after at least 12 hours without CGT. Minor variations lacked statistical significance.

Discussion: The main challenge was the precise replication of ultrasound cross-sections, as lymphatic vessels vary in diameter along their course. Although the same ultrasound equipment was used, consistent cross-section identification was challenging and contributed to variability. Limitations include difficulties in reproducing identical images and patient variability in CGT adherence, underscoring the need for standardized imaging techniques to reduce variability and improve reliability.

Conclusion: Preliminary results suggest that CGT, as part of CDT, does not significantly alter lymphatic vessel size when comparing immediate post-removal imaging with that taken after at least 12 hours without CGT. Further research with a larger sample and refined imaging techniques is necessary to confirm these findings.

Number: 9

Imaging modalities in lymphology

Balázs Mohos^{1, 2}, Chieh-Han John Tzou^{3, 4, 5}

¹Heart and Vascular Center, Semmelweis University, Budapest, Hungary

²Plastic and Reconstructive Surgery, Department of Surgery, County Hospital, Veszprem, Hungary

³Plastic and Reconstructive Surgery, Department of Surgery, Hospital of the Divine Savior, Vienna, Austria

⁴Faculty of Medicine, Sigmund Freud University, Vienna, Austria

⁵TZOU MEDICAL., Lymphology Center, Vienna, Austria

Imaging modalities play an integral role in the early diagnosis and treatment of lymphedema by providing quantitative and qualitative interpretations. However, imaging modalities in lymphedema still face various issues. Most methods lack a universally standardized protocol for diagnosing and staging, which would be beneficial to improve reproducibility and objectivity.

Lymphoscintigraphy (LS) is generally considered the gold standard in confirming the diagnosis of lymphedema, offering quantifiable assessments of lymphatic fluid transport.

Near-infrared fluorescent imaging, also termed indocyanine green (ICG) lymphography, effectively visualizes superficial lymphatic vasculature. Its main application is diagnosing lymphedema and planning locations for lymphaticovenous anastomosis (LVA) operations.

Ultrasonography is widely performed to exclude venous diseases. High- and ultra-high frequency ultrasound is an effective means for lymphatic and vein mapping before LVA operations.

Magnetic resonance lymphangiography (MRL) diagnoses lymphedema by providing information on lymphatic morphology and function, regardless of depth. It depicts fat and fluid excess. MRL reveals possible venous pathology, as well as diagnoses other than lymphedema (recurrent tumor, occult metastasis, lymphangiosarcoma).

Emerging technologies, e.g., bioimpedance spectroscopy, laser tomography, and photoacoustic imaging, can contribute to an earlier diagnosis, a superior treatment plan, and improved outcomes after reconstructive lymphatic surgery.

Imaging modalities facilitate proper patient-, lymph vessel-, and donor-site selection, which are prerequisites for successful lymphatic surgery. Each technique has different characteristics and yields specific information. Thus, they have to be indicated accordingly. This presentation will provide the audience with an understanding and interpretation of these imaging modalities, and our experience will support physicians in outlining a treatment plan.

Reference:

Mohos, B., Tzou, C.-H. J. (2023). “Imaging Modalities for Diagnosis and Treatment of Lymphedema” Plastic Surgery, 5th edition edited by Peter C. Neligan: Volume 4, Trunk and Lower Extremity, edited by David Song and J. P. Hong.

Number: 10

Indications for conventional and MR lymphangiography

Reinhard Kaufmann

Interventional Radiology, Department of Radiology University Hospital Salzburg, Austria

ORCID Number: 0000-0002-0037-5211

Introduction/Background: Lymphangiography and lymphatic interventions have recently gained significant attention in the field of Interventional Radiology. However, many different technical approaches exist for radiologists to visualize the lymphatic system based on either X-ray (conventional) or MRI and, thus, raising the question of what to use when. This presentation aims to summarize the advantages, disadvantages, and future perspectives of conventional and MR lymphangiography.

Material and Methods: The indications for conventional and MR-based lymphangiography were analyzed using in-house data, personal experience, and a review of current literature. A case-based approach was employed to illustrate the practical aspects and benefits of each method.

Results: Indications for conventional or MR lymphangiography include lymphoceles, lymphatic malformations, plastic bronchitis, and preoperative planning, among others. Conventional lymphangiography usually provides higher resolution and offers therapeutic options, particularly in treating lymphatic leakages or malformations. MR lymphangiography, on the other hand, enables 3D visualization of lymphatic structures, is non-invasive and avoids radiation exposure. The choice of modality depends on factors such as the presenting symptoms, therapeutic goals, and availability of these techniques.

Conclusion: With technological advances and growing recognition of lymphatic disorders, lymphangiography has gained prominence in Interventional Radiology. Recent studies show improvements in MR imaging protocols, but also increased experience with lymphatic interventions. Consequently, indications for lymphangiography should be evaluated on an ongoing, case-by-case basis, involving multidisciplinary input and consideration of local resources. In summary, MR lymphangiography offers an excellent approach for most diagnostic purposes, while conventional lymphangiography serves as a potential “theranostic” tool, especially in managing lymphatic leaks and malformations.

Number: 11

Three-dimensional histology for the diagnostic assessment of lymphatic and venous diseases

René Haegerling

Charité-Universitätsmedizin, Berlin, Institute for Medical and Human Genetics, Berlin, Germany

ORCID Number: 0000-0002-6830-2043

Introduction/Background: Fast and accurate histopathological analysis of biopsied tissues or surgical specimens is essential for both histopathological analysis itself and subsequent diagnosis of diseased tissues. However, 2-dimensional slide-based histopathological analysis does not represent tissue structures and molecular targets sufficiently, which aggravates an accurate and spatial analysis of the tissue.

Material and Methods: To overcome these limitations, we have established a 3D histopathology approach based on non-destructive volumetric light-sheet microscopy, which bears the potential to revolutionize the way pathological analysis is done. In comparison to conventional 2D pathology, non-destructive 3D histopathology allows rapid slide-free histological imaging of a whole tissue sample, volumetric analysis of diagnostically-relevant structures such as immune cells or vessels as well as an improved spatial analysis of cells and cell distribution relevant to study, e.g. the vascular microenvironment.

Results: To achieve this, we have successfully established a fluorescence-based analogue of the histological gold-standard staining method, hematoxylin and eosin (H&E) staining, suitable for Light-sheet microcopy. In combination with codon reassignment technology and nanobody-based staining protocols detecting relevant markers such as immune cells, vessels or proliferation state, this approach offers cutting-edge diagnostic phenotyping of the specimen. Due to the non-destructive nature of the optical sectioning methodology, the sample is available for downstream applications such as molecular diagnostics of the previously-imaged specimen. Using this approach, we were able to identify new lymph vessel phenotypes, which will set the basis for future improved histological classification as well as treatment recommendation and prognosis.

Conclusion: In summary, this innovative approach for 3D-histopathology allows more sophisticated and detailed diagnosis of tissue samples from patients with vascular anomalies and has the potential to become the new gold standard in histopathological analysis.