Lymphatic Mapping with Contrast-enhanced Ultrasound for Lymphaticovenous Anastomosis Surgery: How We Do It

Abstract

Lymphaticovenous anastomosis (LVA) surgery is an effective surgery for the treatment of lymphedema in the extremities. Indocyanine green lymphography is the reference standard for visualizing lymphatics for LVA surgery, but it has several limitations; most notably, superficial dermal congestion can mask deeper lymphatic vessels. To overcome the limitations, we add contrast-enhanced ultrasound (CEUS) lymphography. We have previously reported that CEUS lymphography can identify lymphatic vessels for LVA surgery that indocyanine green lymphography does not. Here, we describe how we perform CEUS lymphography, including workflow, technique, and documentation. Before informed consent, the patient must be screened for possible adverse reactions to microbubbles. The procedure involves multiple intradermal injections of the microbubble agent at various sites along the extremity. After each injection, imaging for microbubble uptake by lymphatic vessels is performed using an ultrasound scanner with contrast-specific software. We use sulfur hexafluoride lipid-type A microspheres (Lumason/SonoVue; Bracco Suisse SA), but we are investigating the performance of other Food & Drug Administration–approved microbubble agents for CEUS lymphography. Having a systematic approach to marking the skin can mitigate the hindrance of marking over ultrasound coupling gel. Another benefit of CEUS lymphography is the rapid identification of neighboring veins compatible in size and location for anastomosis. We hold regular scheduled multidisciplinary meetings for coordination of care, discussion of outcomes, quality assurance, and ongoing innovation.

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TECHNIQUE
Successful contrast-enhanced ultrasound (CEUS) lym-
phography involves a team of plastic surgeons, radiolo-
gists, sonographers, and nurses. When lymphaticovenous
anastomosis (LVA) surgery is indicated and scheduled,
the patient is screened for history of allergic reactions to
microbubble-based contrast agents, blood products, albu-
min, polyethylene glycol, or eggs,1 and informed consent is
obtained. A clinical order for CEUS lymphography is usu-
ally entered several weeks in advance for scheduling pur-
poses. A dedicated radiology team ensures the availability
of staff and resources to perform the procedure. Monthly
multidisciplinary meetings are held for coordination of
care, discussion of outcomes, quality assurance, and ongo-
ing innovation.
Outpatient CEUS lymphography can be performed
close to the day of surgery, and topical anesthetic gel
or spray can be used to reduce the pain from needle
injections. We generally perform CEUS lymphography
intraoperatively before indocyanine green (ICG) lym-
phography and LVA surgery. Before the procedure, the
correct patient, site, and side are conrmed. The patient’s
extremity is prepared with ethanol or chlorhexidine; we
have found that betadine-based agents uoresce slightly
under near-infrared imaging used in ICG lymphogra-
phy. The microbubble agent is prepared according to
manufacturer instructions. A total of 15–20 intradermal
injections of microbubbles are performed throughout
Breast
IDEAS AND INNOVATIONS
Summary: Lymphaticovenous anastomosis (LVA) surgery is an effective surgery for
the treatment of lymphedema in the extremities. Indocyanine green lymphography
is the reference standard for visualizing lymphatics for LVA surgery, but it has several
limitations; most notably, supercial dermal congestion can mask deeper lymphatic
vessels. To overcome the limitations, we add contrast-enhanced ultrasound (CEUS)
lymphography. We have previously reported that CEUS lymphography can identify
lymphatic vessels for LVA surgery that indocyanine green lymphography does not.
Here, we describe how we perform CEUS lymphography, including workow, tech-
nique, and documentation. Before informed consent, the patient must be screened
for possible adverse reactions to microbubbles. The procedure involves multiple
intradermal injections of the microbubble agent at various sites along the extrem-
ity. After each injection, imaging for microbubble uptake by lymphatic vessels is per-
formed using an ultrasound scanner with contrast-specic software. We use sulfur
hexauoride lipid-type A microspheres (Lumason/SonoVue; Bracco Suisse SA), but
we are investigating the performance of other Food & Drug Administration–approved
microbubble agents for CEUS lymphography. Having a systematic approach to mark-
ing the skin can mitigate the hindrance of marking over ultrasound coupling gel.
Another benet of CEUS lymphography is the rapid identication of neighboring
veins compatible in size and location for anastomosis. We hold regular scheduled
multidisciplinary meetings for coordination of care, discussion of outcomes, quality
assurance, and ongoing innovation. (Plast Reconstr Surg Glob Open 2023; 11:e5328; doi:
10.1097/GOX.0000000000005328; Published online 12 October 2023.)
SamuelJang, MD*
Samyd S.Bustos, MD†
Austin D.Chen, MD†
Eugene E.Zheng, MD†
Gina K.Hesley, MD*
Nathan J.Brinkman, PharmD,
RPh‡
Jill S.Carter, RVT, RDMS*
Nho V.Tran, MD†
VaheFahradyan, MD†
Christine U.Lee, MD, PhD*
From the *Department of Radiology, Mayo Clinic, Rochester, Minn.;
†Department of Plastic Surgery, Mayo Clinic, Rochester, Minn.;
and ‡Department of Pharmacy, Mayo Clinic, Rochester, Minn.
Received for publication August 25, 2023; accepted August 31,
2023.
Copyright © 2023 The Authors. Published by Wolters Kluwer Health,
Inc. on behalf of The American Society of Plastic Surgeons. This
is an open-access article distributed under the terms of the Creative
Commons Attribution-Non Commercial-No Derivatives License 4.0
(CCBY-NC-ND), where it is permissible to download and share the
work provided it is properly cited. The work cannot be changed in
any way or used commercially without permission from the journal.
DOI: 10.1097/GOX.0000000000005328
Lymphatic Mapping with Contrast-enhanced
Ultrasound for Lymphaticovenous Anastomosis
Surgery: How We Do It
Disclosure statements are at the end of this article,
following the correspondence information.
Related Digital Media are available in the full-text
version of the article on www.PRSGlobalOpen.com.
11
10
12October2023
12
October
2023

PRS Global Open • 2023
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the extremity on both the dorsal and ventral surfaces by
the radiologist, one or two sites at a time. (See gure,
Supplemental Digital Content 1, which displays potential
sites of microbubble injection in the upper extremity.
Intradermal injections of microbubbles are performed at
multiple sites in the extremities. The stars on the upper
extremity show the potential sites of microbubble injec-
tion. Analogous sites can be injected in the lower extrem-
ity. The sites of injection are guided by prior experience,
patient positioning, and the duration of the procedure.
Although the specic sites of injection can vary among
patients, the optimal sites of injection that may demon-
strate the highest yield are being investigated. http://
links.lww.com/PRSGO/C809.)
Each injection consists of 0.3–0.4 mL of microbubble
solution injected through a 25-gauge needle to create a
skin wheal. We found that the 25-gauge needle provides the
most effective intradermal administration without spillage
while providing diagnostic images. It is important to use a
Luer-Lock syringe, as pressure from the intradermal injec-
tion can dislodge the needle from a slip-tip syringe. After
rmly massaging the skin wheal for 10–15 seconds, sterile
ultrasound coupling gel is applied, and scanning is per-
formed with an ML6-15 (4.5–15 MHz) transducer using
the thyroid scanning model on a GE Logiq E9 scanner
(General Electric Healthcare, Wauwatosa, Wisc.), scan-
ning proximally from the injection site. The transducer is
oriented perpendicular (transverse plane) to the long-axis
of the arm. The B-mode and CEUS screen are displayed
side by side to differentiate fascial planes that can seem
echogenic on the CEUS screen. A mechanical index of
0.06-0.08 is used. Microbubble uptake by lymphatic vessels
is seen as a focal echogenic dot extending from the injec-
tion site in the transverse plane and as a linear channel
in the longitudinal plane (Fig.1). An injection site could
reveal no lymphatic vessels or vessels of variable length,
sometimes longer than 30 cm.
Microbubble uptake by lymphatic vessels is marked
on the skin to complete the procedure. As ultrasound
coupling gel considerably hinders marking the skin with
ink-based markers, we use an approach that minimizes
the wipe-and-write frequency. As lymphatic vessels are
Takeaways
Question: How do you perform contrast-enhanced ultra-
sound lymphography for lymphaticovenous anastomosis
surgery preoperative mapping?
Findings: The preparation, the procedure, and the docu-
mentation for performing contrast-enhanced ultrasound
lymphography in the extremities are described. A system-
atic approach to mark the skin is needed. A video tutorial
is included.
Meaning: Ultrasound with intradermal injection of micro-
bubbles can identify lymphatic vessels and potential recip-
ient veins for lymphaticovenous anastomosis surgery in
the extremities.
Fig. 1. Dual display of B-mode and contrast-enhanced ultrasound screens. After intradermal injection
of microbubbles, their uptake by a lymphatic vessel (arrows) is shown in the transverse (A) and the lon-
gitudinal (B) planes. Sometimes, the lymphatic vessels branch into numerous smaller branches, and the
most robust channels are usually marked on the skin at the discretion of the radiologist.

Jang et al • CEUS for LVA
3
identied, the sonographer will pause every 3–5 cm,
and the radiologist will make an indentation in the skin
with a small blunt object, such as the end of an alcohol
swab stick. After wiping off the coupling gel, indelible
ink is used to connect the indented skin marks. Finally,
the trajectories of the identied lymphatic channels are
reimaged with an L6-24D (6–24 MHz) transducer to
identify similar-sized veins within 1 cm of the lymphatic
vessel. Candidate anastomotic veins are marked with
indelible ink. CEUS lymphography image acquisitions
include a cine clip and static images taken at each injec-
tion site. [See Video1 (online), which displays a CEUS
cine clip at a microbubble injection site. A video tuto-
rial demonstrates the entire CEUS lymphography pro-
cedure.] [See Video2 (online), which displays a CEUS
lymphography video tutorial in the upper extremity.]
CEUS lymphography results are reviewed with the plas-
tic surgeon. The surgeon documents the locations of the
anastomoses and how the target lymphatic vessels were
identied (CEUS, ICG, or both) in the operative note
once the LVAs are created. An alphanumeric grid (Fig.2)
can be used to report the anastomotic locations accurately
and consistently for follow-up evaluations and future pro-
viders. Photographs of the extremities are taken before
lymphatic mapping, after CEUS lymphatic mapping and
ICG lymphography, and immediately after surgery. The
microbubble injection sites are assessed for any adverse
reactions. [See gure, Supplemental Digital Content 2,
which displays examples of marked skin after lymphatic
mapping with CEUS and ICG lymphography. In our prac-
tice, CEUS lymphatic mapping is performed before ICG
lymphography. Sometimes, the same lymphatic vessels
are identied by both methods. CEUS lymphatic map-
ping may reveal lymphatic vessels not identied by ICG
lymphography and vice versa. In these photographs, lym-
phatic channels identied by CEUS (dotted and solid blue
Fig. 2. Alphanumeric upper extremity grid. It is often dicult to document and communicate the
exact locations of surgical incisions and anastomosis creation. An 8 × 8 alphanumeric grid system that
encompasses the entire extremity in the surgical position may improve the communication of anasto-
moses created during LVA surgery. Documenting as such provides later proceduralists and surgeons a
precise location of the LVA and potentially aids in follow-up evaluation of anastomosis patency. (Used
with permission of Mayo Foundation for Medical Education and Research, all rights reserved).

PRS Global Open • 2023
4
lines), lymphatic channels identied by ICG lymphogra-
phy (green lines), and potential recipient veins (red dots
and lines) are marked on the skin. http://links.lww.com/
PRSGO/C810.]
DISCUSSION
LVA surgery, also known as lymphovenous bypass, is
an effective surgery for the treatment of lymphedema in
the extremities.2,3 LVA surgery relies on identifying lym-
phatic vessels and their recipient veins. ICG lymphogra-
phy is the reference standard for visualizing lymphatics
for LVA surgery. Its limitations include the inability to
detect lymphatic vessels masked by supercial lymphatic
congestion, especially in later stages of lymphedema, and
contraindication in patients with iodine sensitivity. Our
early experience demonstrated that CEUS could iden-
tify lymphatic channels not seen by ICG lymphography,
leading to additional successful anastomoses, including
in patients where no targetable lymphatic vessels were
visualized by ICG lymphography.4,5 In addition to ICG
lymphography, CEUS lymphography is the standard of
care examination at our institution because of its clini-
cal benets before performing LVA surgery. As with other
sonographic examinations, the result may vary by opera-
tor experience.
The safety proles of commercially available micro-
bubble agents are well published. In the United States,
there are three FDA-approved microbubble agents: sul-
fur hexauoride lipid-type A microspheres (Lumason/
SonoVue), perutren protein-type A microspheres
(Optison), and perutren lipid microspheres (Denity/
Luminity). Peruorobutane microspheres (Sonozoid),
although not available in the United States, are widely
used in Europe and parts of Asia, and have shown uptake
by lymphatic vessels in the extremities of healthy volun-
teers.6 Microbubbles are not labeled for intradermal injec-
tion by the FDA. For intravenous injections, microbubbles
impose a very low risk of adverse reactions;1 intradermal
injections of microbubbles have an even lower risk prole.
CEUS has been described for mapping sentinel lymph
nodes in breast cancer at least since 2006 in thousands of
patients in the research setting.7 After appropriate exclu-
sion of patients with signicant comorbidities or history of
allergy to ultrasound contrast agents, many studies report
no adverse reaction or minor skin irritation in extremely
low numbers of patients related to the intradermal
injection of microbubbles.8–10 At our institution, CEUS
lymphatic mapping is performed with Lumason, primarily
because of availability, prepared according to the manu-
facturer instructions without dilution. The utility of other
microbubble agents for lymphatic mapping is currently
under investigation.
Christine U. Lee, MD, PhD
Mayo Clinic
200 First St, SW
Rochester, MN 55920
E-mail: lee.christine@mayo.edu
DISCLOSURE
The authors have no nancial interest to declare in relation to
the content of this article.
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