Finding an optimal method for imaging lymphatic vessels of the upper limb

Characterizing Normal Upper Extremity Lymphatic Flow with 99mTc In-House Dextran: A Retrospective Study

Lymphoscintigraphy evaluates the lymphatic system using radiocolloid compounds like 99mTc-sulfur colloid and 99mTc-nanocolloid, which vary in particle size and distribution timing. A local in-house Dextran kit (15-40 nm) was developed in 2005 and began clinical use in 2008 to localize sentinel lymph nodes; diagnose lymphedema; and detect lymphatic leakage. The normal drainage pattern remains unexplored. We retrospectively analyzed 84 upper extremity lymphoscintigraphies from 2008 to 2021. 99mTc in-house Dextran was intradermally injected into both hands, followed by whole-body imaging at specified intervals (≤15 min; 16-30 min; 31-45 min; 46-60 min), with some receiving delayed imaging. Visual and quantitative analyses recorded axillary and forearm lymph nodes and liver, kidney, and urinary bladder activity. Results showed 92% (77/84) upper extremity lymphatic tract visualization within 45 min. Axillary node detection rates increased from 46% (≤15 min) to 86% (46-60 min). Delayed imaging further revealed nodes. Epitrochlear or brachial node visualization was rare (4%, 3/84). Hepatic, renal, and urinary bladder activity was noted in 54%, 71%, and 93% at 1 h, respectively. The axillary node uptake ratio was minimal (<2.5% of injection site activity; median 0.33%). This study characterizes normal upper extremity lymphatic drainage using 99mTc in-house Dextran, offering insights into its clinical application.

Lymphoscintigraphy is frequently recommended but seldom used in a "real world setting"

OBJECTIVE

Lymphedema (LED) lacks a standard, simple, guiding noninvasive diagnostic test, unlike the two other circulatory disorders-arterial or venous disease. Lymphoscintigraphy (LSG) has been recommended by several guidelines as the diagnostic test of choice for LED. Several recent expert panels, however, have suggested from anecdotal experience that LSG was used infrequently, and that the diagnosis of LED is usually based on clinical examination.

METHODS

To determine the use of LSG in a large real-world LED population, the International Business Machines MarketScan Research Database was examined from April 2012 to March 2020 for patients with a new diagnosis of LED (the index date). Use of LSG (LSG+) was ascertained during the period beginning 12 months prior to the initial coding of a LED diagnosis and ending 12 months after the index date based on the corresponding Current Procedural Terminology code; LSG use for sentinel node mapping at the time of oncologic surgery was excluded. Demographic profiles, comorbidities, and causes of LED among patients with and without evidence of LSG were characterized.

RESULTS

We identified 57,674 patients, aged ≥18 years, who had a new diagnosis of LED and health care coverage for ≥12 months before and after this index date. Only a small number (1429; 2.5%) of these patients underwent LSG during the study period. The LSG + cohort was younger (53.7 vs 60.7 years), had a higher proportion of women (91.3% vs 73.4%), but a lower percentage of diabetes (12.8% vs 27.5%), heart failure (2.2% vs 8.7%), hypertension (32.4% vs 51.0%), and obesity (15.1% vs 22.2%) compared with the LED population who did not undergo LSG (all P < .001). Most importantly, the use of LSG for diagnosis varied with the etiology of LED (LSG was most frequently utilized among patients with melanoma-LED (9.5%) and patients with breast cancer-LED (6.7%), in contrast to patients with advanced venous disease-related LED (1.1%; P < .05 for both comparisons).

CONCLUSIONS

Despite four guidelines recommending LSG, including the Guidelines of the American Venous Forum (Handbook of Venous and Lymphatic Disease-4th edition), which recommended LSG "for the initial evaluation of patients with LED" with a 1B recommendation, LSG plays a minor role in establishing the diagnosis of LED in the United States. This underlines the need for a better, simple diagnostic test for LED to complement clinical examination.

Microneedle array delivery of Yersinia pestis recapitulates bubonic plague

Fleas transmit Yersinia pestis directly within the dermis of mammals to cause bubonic plague. Syringe-mediated inoculation is widely used to recapitulate bubonic plague and study Y. pestis pathogenesis. However, intradermal needle inoculation is tedious, error prone, and poses a significant safety risk for laboratorians. Microneedle arrays (MNAs) are micron-scale polymeric structures that deliver materials to the dermis, while minimizing the risk of needle sticks. We demonstrated that MNA inoculation is a viable strategy to recapitulate bubonic plague and study bacterial virulence by defining the parameters needed to establish a lethal infection in the mouse model and characterizing the course of infection using live-animal optical imaging. Using MNAs, we also demonstrated that Y. pestis must overcome calprotectin-mediated zinc restriction within the dermis and dermal delivery of an attenuated mutant has vaccine potential. Together, these data demonstrate that MNAs are a safe alternative to study Y. pestis pathogenesis in the laboratory.

Lymphatic remapping by long-term lymphoscintigraphy follow-up in secondary lymphedema after breast cancer surgery

The purpose of the study is to investigate long-term changes on lymphoscintigraphy and their association with clinical factors in breast cancer-related lymphedema (BCRL) patients. This single-center cohort study included BCRL patients who underwent baseline and follow-up lymphoscintigraphy. The percentage of excessive circumference (PEC) of the affected upper limb compared with the unaffected side was used as an indicator of the clinical severity of BCRL. Each 99mTc-phytate lymphoscintigraphy image was categorized according to the Taiwan lymphoscintigraphy staging system. Clinical parameters and the lymphoscintigraphy stage at baseline and follow-up were compared and analyzed. Eighty-seven patients were included. Baseline and follow-up lymphoscintigraphies were performed at median 7 (interquartile range [IQR]: 2‒14) and 78 (IQR: 49‒116) months after surgery, respectively. Both lymphoscintigraphy stage and PEC showed variable change with overall increases in their severity. Stepwise multivariable analysis revealed follow-up lymphoscintigraphy stage (P = 0.001) to be independent variables for PEC at follow-up, however, baseline lymphoscintigraphy stage was not. The clinical courses of BCRL and patients' lymphoscintigraphy patterns showed diverse changes over long-term follow-up. In addition to initial lymphoscintigraphy for diagnosis, lymphatic remapping by follow-up lymphoscintigraphy can be useful to visualize functional changes in the lymphatic system that may guide the optimal management in BCRL.

Imaging of the Lymphatic Vessels for Surgical Planning: A Systematic Review

BACKGROUND

Secondary lymphedema is a common complication after surgical or radiotherapeutic cancer treatment. (Micro) surgical intervention such as lymphovenous bypass and vascularized lymph node transfer is a possible solution in patients who are refractory to conventional treatment. Adequate imaging is needed to identify functional lymphatic vessels and nearby veins for surgical planning.

METHODS

A systematic literature search of the Embase, MEDLINE ALL via Ovid, Web of Science Core Collection and Cochrane CENTRAL Register of Trials databases was conducted in February 2022. Studies reporting on lymphatic vessel detection in healthy subjects or secondary lymphedema of the limbs or head and neck were analyzed.

RESULTS

Overall, 129 lymphatic vessel imaging studies were included, and six imaging modalities were identified. The aim of the studies was diagnosis, severity staging, and/or surgical planning.

CONCLUSION

Due to its utility in surgical planning, near-infrared fluorescence lymphangiography (NIRF-L) has gained prominence in recent years relative to lymphoscintigraphy, the current gold standard for diagnosis and severity staging. Magnetic resonance lymphography (MRL) gives three-dimensional detailed information on the location of both lymphatic vessels and veins and the extent of fat hypertrophy; however, MRL is less practical for routine presurgical implementation due to its limited availability and high cost. High frequency ultrasound imaging can provide high resolution imaging of lymphatic vessels but is highly operator-dependent and accurate identification of lymphatic vessels is difficult. Finally, photoacoustic imaging (PAI) is a novel technique for visualization of functional lymphatic vessels and veins. More evidence is needed to evaluate the utility of PAI in surgical planning.

Relation Between Early Disturbance of lymphatic transport Visualized With Lymphofluoroscopy and Other Clinical Assessment Methods in Patients With Breast Cancer

INTRODUCTION

Lymphedema of the upper extremity is one of the most feared complications following breast cancer treatment. Lymphofluoroscopy is a sensitive instrument for detection of lymphedema and visualization of superficial lymphatic transport, thus suitable for early detection. Early detection of lymphedema is important as it can prevent lymphedema to progress into more severe stages and minimalize impact on quality of life and medical costs.

OBJECTIVE

To determine agreement between the presence of early disturbance of the lymphatic transport and outcome of clinical measurement tools evaluating the development of lymphedema.

METHODS

A prospective study was conducted in 128 breast cancer patients scheduled for breast cancer surgery. Patients were evaluated before surgery and 1, 3-, 6-, 9-, and 12-months' post-surgery. Cohen's Kappa was used to determine agreement between presence of early disturbance in lymphatic transport and presence of pitting/increased skinfold thickness/increased Percentage Water Content ratio (PWC)/increased arm-hand volume (circumference measures and water displacement).

RESULTS

For pitting status (Kappa 0.23), for skinfold thickness (Kappa 0.29) and the PWC ratio (Kappa 0.21) a minimal agreement was found. The circumference measurement had a minimal agreement for 5% volume difference (Kappa 0.22) and no agreement for 3% volume difference (Kappa 0.19). Sensitivity was weak for all clinical assessments. The specificity was excellent for pitting status, skinfold thickness, PWC ratio, and for 5% volume difference. For 3% a high specificity was found.

CONCLUSION

The clinical tools assessed in this study were not able to predict an early disturbance of the lymphatic transport seen on lymphofluoroscopy.

Lymphoscintigraphy for the diagnosis of extremity lymphedema: Current controversies regarding protocol, interpretation, and clinical application

Appropriate diagnosis, staging and a further selection of the best treatment are fundamental for the management of patients with extremity lymphedema. Several clinical and imaging tools have been described for these purposes. Lymphoscintigraphy is still considered the gold standard imaging modality for diagnosing lymphedema. However, protocol variability and poor image resolution can make the interpretation challenging. Here, we reviewed technical aspects of lymphoscintigraphy, interpretation of the lymphoscintigraphy findings, staging, and its clinical application.

Pharmacokinetics and Skin Tolerability of Intracutaneous Zolmitriptan Delivery in Swine Using Adhesive Dermally Applied Microarray

Adhesive Dermally Applied Microarray (ADAM) is a new drug-delivery system that uses microprojections (340-μm long) for intracutaneous drug self-administration. We formulated zolmitriptan, a well-accepted and commonly used migraine medication, for administration using ADAM. In vivo studies were conducted in female prepubescent Yorkshire pigs using ADAM 1.9-mg zolmitriptan applied to the inner thigh and left in place for 1 h. Pharmacokinetic studies showed that the ADAM 1.9-mg zolmitriptan was delivered with high efficiency (85%) and high absolute bioavailability (77%). Furthermore, in vivo evaluation showed a rapid systemic absorption with a median T_max of 15 min. Skin biopsies of the treatment sites showed a mean depth of microprojection penetration of 105.4 ± 3.6 μm. Mass spectrometry imaging showed that the zolmitriptan after 1 h of patch wear time was predominantly localized to the dermis. ADAM zolmitriptan was well tolerated with a transient mild-to-moderate erythema response. The findings in these studies, particularly the rapid zolmitriptan absorption profile after intracutaneous administration, provided validation to advance ADAM zolmitriptan development.

Evaluation of lymphatic compensation by lymphoscintigraphy in the postoperative period of breast cancer surgery with axillary dissection

Objective

To evaluate postoperative lymphatic compensation in the upper limb after mastectomy with axillary dissection.

Subjects and methods

Twenty-three patients who underwent lymphoscintigraphy before and 60 days after surgery were enrolled from September 2006 to June 2007, in Campinas, Brazil. Protocol examination consisted in static imaging of each upper limb in semi-flexion and thoracic imaging after 10 min and 1 and 2 hr after subcutaneous injection of 1 mCi (37 MBq) of 99mTc dextran into the dorsum of the hand. A comparative analysis was made of hepatic uptake of the radiopharmaceutical, velocity of axillary lymph node visualization (I, visible at 10 min; II, at 1 hr; III, at 2 hr; IV, not visible) and degree (intensity) of uptake (a, marked; b, moderate; c, mild; d, absent) before and 60 days after surgery.

Results

In the preoperative period, 3 (13%) patients were considered to have an optimal pattern (Ia) and 2 (9%) showed total involvement (IVd). Compared to velocity in the postoperative period, 9 (39%) patients showed no difference, 5 (22%) improved, 9 (39%) became worse, and one was considerably worse. Regarding the degree, 10 (43%) patients showed no difference, 9 (39%) became worse, and 4 (17%) improved. Regarding classification, 2 (9%) patients had an optimal lymphatic pattern (Ia) and 3 (13%) had total involvement (IVd). No patient presented decreased hepatic uptake after surgical treatment.

Conclusions

The study found relevant changes in preoperative and postoperative lymphoscintigraphy, demonstrating the existence of functional differences in the lymphatic system of the upper limb. Alterations in lymphatic drainage pattern may already be perceived 60 days postoperatively, as can signs of lymphovenous anastomoses.

The clinical yield of SPECT/CT for the assessment of lymphatic transport disorders

Ziel dieser Studie war zu untersuchen, ob die zusätzliche Bildgebung mittels SPECT/CTTechnik den diagnostischen Wert der planaren Lymphszintigraphie bei Patienten mit Lymphtransportstörungen verbessern kann. Patienten, Methoden: Über einen festgelegten Zeitraum von zwei Jahren wurden 36 konsekutive Patienten (27 Frauen, 9 Männer, Alter 27–87 Jahre) in unsere Studie eingeschlossen. Zusätzlich zur planaren Lymphszintigraphie wurden weitere ergänzende SPECT/CT-Akquisitionen der betroffenen Extremitäten oder des Körperstamms durchgeführt. Insgesamt erfolgte eine prospektive Auswertung von 48 anatomischen Lymphabflussregionen mittels planarer Szintigraphie und tomographischer SPECT/CT. Ergebnisse: In 28/48 Fällen (58%) brachte die SPECT/CTBildgebung klinisch relevante Zusatzinformationen im Vergleich zur planaren Technik; darunter 27 bezüglich der exakten anatomischen Lokalisation der Transportstörungen sowie 8 Fälle, bei denen die Ausdehnung der lymphogenen Störung mittels SPECT/CT ausgedehnter beurteilt wurde als in der alleinigen planaren Szintigraphie. In 3 Fällen konnte durch die SPECT/CT differenzialdiagnostisch zwischen Lymphknoten versus Lymphozele differenziert werden. In keinem der Fälle konnten Lymphgefäße/-transplantate durch die morphologische CT-Komponente dargestellt werden. Schlussfolgerungen: Die zusätzlich zur planaren Lymphszintigraphie durchgeführte SPECT/CT präzisiert die anatomische Zuordnung lymphogen bedingter Transportstörungen und somit die Abschätzung der Ausdehnung der Pathologie. Des Weiteren löst sie Überlagerungseffekte anatomischer Strukturen durch die tomographische Akquisition auf und ermöglicht die Differenzialdiagnose von Lymphknoten versus Lymphozelen.

Tc-99m-Human Serum Albumin Transit Time as a Measure of Arm Breast Cancer-Related Lymphedema

BACKGROUND

Lymphoscintigraphy has often been used for evaluating arm lymphatic dysfunction, but no optimal approach for quantification has so far emerged. We propose a quantifiable measure of lymphatic function that we applied in patients treated for breast cancer.

METHODS

Eleven patients, aged 34-68 years, with unilateral arm lymphedema following breast cancer treatment underwent bilateral lymphoscintigraphy using intradermal injection in both hands of technetium-99m-labeled human serum albumin and sequential 5 min imaging for 5 hours. The mean transit time (MTT) in the arms was calculated based on time activity curves generated from injection site and arm regions. Visual lymphedema scoring was performed based on dermal backflow and lymph node presence. Excess arm volume was calculated from circumference measurements.

RESULTS

The MTT (mean ± SD) was significantly longer in the lymphedema arm than in the normal arm: 60.1 ± 27.7 versus 5.4 ± 2.5 minutes (mean difference, 54.7 minutes; 95% confidence interval, 36.5-72.9 minutes; P < 0.0001). Patients with previous erysipelas infection had significantly longer MTT than other patients (mean difference, 43.7 minutes; 95% confidence interval, 18.6-68.7 minutes; P < 0.001). There was a positive correlation between MTT and excess arm volume (r = 0.64; P = 0.04) and number of lymph nodes removed (r = 0.65; P = 0.03) but no correlation between visual score and MTT.

CONCLUSION

Measurements of MTT were able to discriminate lymphedema from healthy arm and MTT correlated with relevant markers for lymphedema severity. We encourage further research using the MTT approach for monitoring lymphedema and evaluation of treatment response.

Evaluation of the Upper Limb Lymphatic System: A Prospective Lymphoscintigraphic Study in Melanoma Patients and Healthy Controls

BACKGROUND

Current research on the upper limb lymphatic system mainly studies breast cancer patients with unilateral lymphedema. Without preoperative lymphoscintigraphy, the contralateral limb is used as a control, assuming that it is functionally intact. Few lymphoscintigraphic studies investigate patients before any axillary surgery. The purpose of this study was to evaluate, through lymphoscintigraphy, the preoperative condition of the upper limb lymphatic system in melanoma patients and healthy controls.

METHODS

Two groups were studied: the study group (16 patients with trunk/upper limb melanoma candidates for axillary sentinel lymph node biopsy) and the control group (10 healthy volunteers). All subjects underwent upper limb lymphoscintigraphy. Lymphoscintigraphic images were classified into three patterns based on the tracer appearance time in the axillary nodes. Type I, 20 minutes; type II, 60 minutes; and type III, 120 minutes. Statistical analysis was used to assess the relationship between lymphoscintigraphic patterns and clinical variables and to compare patterns of distribution.

RESULTS

Lymphoscintigraphic patterns were asymmetric in 37.5 percent (study group) and 50 percent (control group). Type III was the most common pattern. There was no significant association between lymphoscintigraphic patterns and considered clinical variables. There was no significant difference in the lymphoscintigraphic pattern distribution of the two groups (p = 0.870).

CONCLUSION

The authors' findings show wide differences and an often "slow" tracer appearance time in patients with intact lymphatic system, questioning the use of contralateral limb as control and transportation time greater than 30 minutes as criteria for identification of lymphatic alterations.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Diagnostic, IV.

The effect of prophylactic lymphovenous anastomosis and shunts for preventing cancer-related lymphedema: a systematic review and meta-analysis

BACKGROUND

Lymphedema is one of the most dreaded side effects to any cancer treatment involving lymphadenectomy. Progressed lymphedema is adversely complex and currently there is no widely acknowledged curative treatment. Therefore recent focus has shifted to risk reduction and prevention. It has been hypothesized that bypassing lymphatic vessels to veins prophylactically, could minimize the lymphatic dysfunction seen following lymphadenectomy.

METHODS

To investigate this possible future treatment modality, we performed a systematic meta-analysis of studies treating patients with prophylactic lymphovenous analysisstomosis (LVA) for the prevention of secondary lymphedema following lymphadenectomy. A systematic search yielded 12 articles included in the qualitative analysis and four of these were further eligible to be included in the quantitative analysis.

RESULTS

We found that patients treated with prophylactic LVA had a significant reduction in lymphedema incidence (Relative risk: 0.33, 95%CI: 0.19 to 0.56) when compared to patients receiving no prophylactic treatment (P < 0.0001).

CONCLUSION

Prophylactic LVA in relation to lymphadenectomy shows promising results, however because of the low number of eligible studies and method heterogeneity between studies, there is an urgent need for uniformly high quality studies, before the treatment can be concluded effective.

Lymphatic Function in the Early Postoperative Period of Breast Cancer Has No Short-Term Clinical Impact

OBJECTIVE

To evaluate by lymphoscintigraphy the lymphatic function in the preoperative period up to 2 months after surgery for breast cancer, and the relationship between the lymphatic function with clinical features and physical complications.

METHODS

One hundred and five women were studied before and 2 months after surgery to treat breast cancer. On each occasion, inspection and palpation of surgical wound, upper limb circumference, and lymphoscintigraphy were performed. Lymphatic function analysis consisted of velocity of axillary lymph node (LN) visualization; intensity of LN uptake; collateral circulation; dermal backflow; and hepatic uptake.

RESULTS

In the postoperative period, there was a significant worsening of the degree of LN uptake (p = 0.0003) and in the velocity of LN visualization (p = 0.01). No significant differences in dermal backflow (p = 0.4) and collateral circulation (p = 0,07) were observed. There was a significant increase in liver absorption (p = 0.0002). 37.1% of the patients developed seroma, 11.2% dehiscence, and 25.8% infection. No relationship was found between lymphoscintigraphy changes and postoperative complications or clinical characteristics.

CONCLUSION

Lymphoscintigraphy, performed 60 days post surgery for breast cancer, can detect a worsening in lymphatic drainage and some sign of lymphatic changes. These changes are not related to clinical characteristics and physical complications.

Near-Infrared Fluorescence Lymphatic Imaging to Reconsider Occlusion Pressure of Superficial Lymphatic Collectors in Upper Extremities of Healthy Volunteers

BACKGROUND

There are very little scientific data on occlusion pressure for superficial lymphatic collectors. Given its importance in determining the transport capacity of lymphatic vessels, it is crucial to know its value. The novel method of near-infrared fluorescence lymphatic imaging (NIRFLI) can be used to visualize lymphatic flow in real time. The goal of this study was to see if this method could be used to measure the lymphatic occlusion pressure.

METHODS

We observed and recorded lymph flow in the upper limb of healthy volunteers through a transparent cuff using near-infrared fluorescence lymphatic imaging. After obtaining a baseline of the lymph flow without pressure inside the cuff, the cuff was inflated by increments of 10 mm Hg starting at 30 mm Hg. A NIRFLI guided manual lymphatic drainage technique named "Fill & Flush Drainage Method" was performed during the measurement to promote lymph flow. Lymphatic occlusion pressure was determined by observing when lymph flow stopped under the cuff.

RESULTS

We measured the lymphatic occlusion pressure on 30 healthy volunteers (11 men and 19 women). Mean lymphatic occlusion pressure in the upper limb was 86 mm Hg (CI ±3.7 mm Hg, α = 0.5%). No significant differences were found between age groups (p = 0.18), gender (p = 0.12), or limb side (p = 0.85).

CONCLUSIONS

NIRFLI, a transparent sphygmomanometer cuff and the "Fill and Flush" manual lymphatic drainage method were used to measure the lymphatic occlusion pressure in 30 healthy humans. That combination of these techniques allows the visualization of the lymph flow in real time, while ensuring the continuous filling of the lymph collectors during the measurement session, reducing false negative observations. The measured occlusion pressures are much higher than previously described in the medical literature.

Comparison of Models for Bubonic Plague Reveals Unique Pathogen Adaptations to the Dermis

Vector-borne pathogens are inoculated in the skin of mammals, most likely in the dermis. Despite this, subcutaneous (s.c.) models of infection are broadly used in many fields, including Yersinia pestis pathogenesis. We expand on a previous report where we implemented intradermal (i.d.) inoculations to study bacterial dissemination during bubonic plague and compare this model with an s.c.

MODEL

We found that i.d. inoculations result in faster kinetics of infection and that bacterial dose influenced mouse survival after i.d. but not s.c. inoculation. Moreover, a deletion mutant of rovA, previously shown to be moderately attenuated in the s.c. model, was severely attenuated in the i.d.

MODEL

Lastly, based on previous observations where a population bottleneck from the skin to lymph nodes was observed after i.d., but not after s.c., inoculations, we used the latter model as a strategy to identify an additional bottleneck in bacterial dissemination from lymph nodes to the bloodstream. Our data indicate that the more biologically relevant i.d. model of bubonic plague differs significantly from the s.c. model in multiple aspects of infection. These findings reveal adaptations of Y. pestis to the dermis and how these adaptations can define the progression of disease. They also emphasize the importance of using a relevant route of infection when addressing host-pathogen interactions.

Primary lymphedema of the lower limb: the clinical utility of single photon emission computed tomography/CT

Objective

The aim of this prospective study was to determine whether the additional use of the single photon emission computed tomography/CT (SPECT/CT) technique improves the diagnostic value of planar lymphoscintigraphy in patients presenting with primary lymph edema of the lower limb.

Materials and Methods

For a defined period of three years (April 2011-April 2014) a total of 34 consecutive patients (28 females; age range, 27-83 years) presenting with swelling of the leg(s) suspicious of (uni- or bilateral, proximal or distal) primary lymphedema were prospectively examined by planar lymphoscintigraphy (lower limbs, n = 67) and the tomographic SPECT/CT technique (anatomical sides, n = 65).

Results

In comparison to pathological planar scintigraphic findings, the addition of SPECT/CT provided relevant additional information regarding the presence of dermal backflow (86%), the anatomical extent of lymphatic disorders (64%), the presence or absence of lymph nodes (46%), and the visualization of lymph vessels (4%).

Conclusion

As an adjunct to planar lymphoscintigraphy, SPECT/CT specifies the anatomical correlation of lymphatic disorders and thus improves assessment of the extent of pathology due to the particular advantages of tomographic separation of overlapping sources. The interpretation of scintigraphic data benefits not only in baseline diagnosis, but also in physiotherapeutical and microsurgical treatments of primary lymphedema.

Reproducibility of lymphoscintigraphic evaluation of the upper limb

BACKGROUND

Although reproducibility studies are missing, a lymphoscintigraphic evaluation of the upper limb is often used in routine practice to diagnose lymphedema and in clinical research, for example, to investigate the effect of a physical treatment. Therefore, the aim of the present study was to investigate the reproducibility of the lymphoscintigraphic evaluation of the upper limb.

METHODS AND RESULTS

In breast cancer patients, 20 lymphoscintigraphic evaluations of the upper limb were performed on two test occasions with an interval of 1 week. (99m)Tc nanocol was injected subcutaneously in the hand. A standardized protocol was applied. In the early phase, two static images of the injection places were taken and in between dynamic images of both axilla during 40 min (15 min rest, 15 min squeezing a ball, and 15 min rest). After a break of 70 min, a static image of the injection places and of the axilla was made. At the end, a partial whole body image was acquired. A strong reproducibility was found for the following quantitative variables (ICC 0.75 to 0.85): change of uptake in axilla during the break; change of extraction from hands during the break; and extraction and uptake in the late phase. The other quantitative variables (i.e., extraction form the hands in the early phase, time of arrival, accumulation rate, and uptake in axilla in the early phase) had weak to moderatie reproducibility (ICC 0.07 to 0.70). All qualitative variables (i.e., number of lymph nodes in the axilla, upper arm and elbow/lower arm, gradation of lymph collectors in upper or lower arm and of dermal backflow, and presence of lymph collaterals) had strong to very strong reproducibility (ICC 0.76 to 1.00).

CONCLUSION

A lymphoscintigraphy of the upper limb is a reproducible imaging tool to assess lymph transport quantitatively and qualitatively.

Imaging the lymphatic system

Visualization of the lymphatic system is clinically necessary during diagnosis or treatment of many conditions and diseases; it is used for identifying and monitoring lymphedema, for detecting metastatic lesions during cancer staging and for locating lymphatic structures so they can be spared during surgical procedures. Imaging lymphatic anatomy and function also plays an important role in experimental studies of lymphatic development and function, where spatial resolution and accessibility are better. Here, we review technologies for visualizing and imaging the lymphatic system for clinical applications. We then describe the use of lymphatic imaging in experimental systems as well as some of the emerging technologies for improving these methodologies.

A quantitative examination of lymph drainage from perilesion skin in human melanoma

BACKGROUND

An increase in lymph flow from melanomas to draining lymph nodes has been reported in animal studies. It has been postulated that this contributes to metastatic potential of cancers. Data from animal studies are not easily extrapolated to humans; animal studies use immunosuppressed animals modified to overexpress lymphangiogenic growth factors, injected with human tumor cell lines, or manipulated to develop aggressive tumors. Human studies are required to investigate lymph flow in humans with cancers such as melanoma.

METHODS AND RESULTS

The present study aims to quantify the removal rate constant k (a measure of local lymph flow per unit volume of distribution of the radiotracer) from the vicinity of melanomas, benign nevi, and normal skin in humans in vivo using quantitative lymphoscintigraphy (QL). 16 patients with pigmented lesions underwent QL to quantify k near the lesion (k(perilesion)) and in contralateral matched normal skin (k(control)). The lesions were then excised and, based on histological outcome, the patients were divided into two groups: benign nevus (n=9) and melanoma (n=7). There was no difference between k(perilesion) and k(control) in either the benign naevus (p=0.29, paired t test) or the melanoma group (p=0.93). k(perilesion) in melanomas (0.233±0.123% min(-1)) was not increased relative to k(perilesion) in benign nevi (0.376±0.231% min(-1), p=0.16, unpaired t test).

CONCLUSIONS

We found no evidence for increased lymphatic drainage in melanoma relative to benign nevi or normal matched skin in humans.

Lymph node dissection--understanding the immunological function of lymph nodes

Lymph nodes (LN) are one of the important sites in the body where immune responses to pathogenic antigens are initiated. This immunological function induced by cells within the LN is an extensive area of research. To clarify the general function of LN, to identify cell populations within the lymphatic system and to describe the regeneration of the lymph vessels, the experimental surgical technique of LN dissection has been established in various animal models. In this review different research areas in which LN dissection is used as an experimental tool will be highlighted. These include regeneration studies, immunological analysis and studies with clinical questions. LN were dissected in order to analyse the different cell subsets of the incoming lymph in detail. Furthermore, LN were identified as the place where the induction of an antigen-specific response occurs and, more significantly, where this immune response is regulated. During bacterial infection LN, as a filter of the lymph system, play a life-saving role. In addition, LN are essential for the induction of tolerance against harmless antigens, because tolerance could not be induced in LN-resected animals. Thus, the technique of LN dissection is an excellent and simple method to identify the important role of LN in immune responses, tolerance and infection.

Lymphatic dysfunction in the apparently clinically normal contralateral limbs of patients with unilateral lower limb swelling

PURPOSE

To determine how often lymphatic dysfunction is bilateral when, clinically, lymphedema appears unilateral.

METHODS

Lymphoscintigraphy was performed after subcutaneous Tc-99m-nanocolloid injection in the first webspaces of both feet. The percentage of injected radioactivity accumulating in the ilioinguinal regions was recorded in dedicated images separately acquired at 60 and 180 minutes after injection.

RESULTS

Within a consecutive series of 204 patients, 74 had unilateral clinical lymphedema of whom 68 had abnormal scintigraphy. Of these 68 patients, 46 had unilateral abnormal scintigraphy affecting the clinically abnormal limb, but 20 patients had bilateral abnormal scintigraphy and 2 had unilateral abnormal scintigraphy in the clinically unaffected limb. Thus, 32% (22/68) of patients in whom clinical lymphedema appeared to be unilateral, nevertheless, had abnormal scintigraphy in the clinically normal limb. Twenty-nine patients had no clinical evidence of lymphedema in either limb and were scintigraphically normal bilaterally. Mean ilioinguinal nodal accumulation at 180 minutes in the 44 limbs of 22 of these clinically and scintigraphically normal patients (dedicated ilioinguinal imaging was not performed in all patients) was 13.1% (standard deviation, 8.8%), higher (P = 0.02) than the mean value of 9.3% (standard deviation, 5.0%) in the clinically and scintigraphically normal contralateral limbs of 39 patients with unilateral clinical lymphedema.

CONCLUSIONS

In the presence of unilateral lymphedema, the contralateral limb is often also abnormal. On lymphoscintigraphy, therefore, care should be taken before diagnosing unilateral lymphatic dysfunction. Quantification should be included in routine lymphoscintigraphy, as reduced ilioinguinal nodal accumulation may be the only apparent abnormality.

What about pain in disorders of consciousness?

The management and treatment of acute pain is very difficult in non-communicative patients with disorders of consciousness (i.e., vegetative state/unresponsive wakefulness syndrome (VS/UWS) and minimally conscious state), creating an ethical dilemma for caregivers and an emotional burden among both relatives and caregivers. In this review, we summarize recent findings about the neural substrates of nociception and pain in VS/UWS patients as well as recent behavioral assessment methods of nociception specifically designed for patients in altered states of consciousness. We will finally discuss implications for pain treatment in these patients.

Minimally invasive quantification of lymph flow in mice and rats by imaging depot clearance of near-infrared albumin

There is a lack of available methods to noninvasively quantify lymphatic function in small experimental animals, a necessity for studies on lymphatic system pathophysiology. We present a new method to quantify lymph flow in mice and rats, based on optically monitoring the depot clearance of near-infrared fluorescently labeled albumin and subsequent calculation of removal rate constants (k). BSA was conjugated with Alexa680 NHS ester and remained stable in protein-rich solutions without free dye dissociation. To assess lymph flow, mice or rats were imaged every 30 or 60 min during a 3- to 6-h period following an intradermal injection of 0.5 or 1 μl Alexa680-albumin. Mice were awake between measurements, whereas rats were anesthetized throughout the experiment. The k, a parameter defined as equivalent to lymph flow, was calculated from the slopes of the resultant log-linear washout curves and averaged -0.40 ± 0.03 and -0.30 ± 0.02%/min for control C57BL/6 and C3H mice, respectively. Local administration of the vasoconstrictor endothelin-1 in mice led to a significant reduction in k, whereas overhydration in rats increased k, reflecting the coupling between capillary filtration and lymph flow. Furthermore, k was 50% of wild type in lymphedema Chy mice where dermal lymphatics are absent. We conclude that lymph flow can be determined as its rate constant k by optical imaging of depot clearance of submicroliter amounts of Alexa680-albumin. The method offers a minimally invasive, reproducible, and simple alternative to assess lymphatic function in mice and rats.

Comparison of efficacy of Tc-99m HIG and Tc-99m nanocolloid on sentinel lymph node mapping in patients with breast cancer

BACKGROUND AND AIM

This study compared the effectiveness of Tc-99m human polyclonal immunoglobulin (HIG) and Tc-99m nanocolloid at detecting sentinel lymph nodes (SLNs) with lymphoscintigraphy and an intraoperative gamma-probe (IGP) in patients with early breast cancer.

METHODS

The study group consisted of 50 women; 25 patients each were given Tc-99m HIG or Tc-99m nanocolloid for lymphoscintigraphy. Then, intraoperative SLN localization with IGP was performed. The results of IGP, lymphoscintigraphy, blue dye injected just before surgery, and pathology were compared.

RESULTS

In the Tc-99m HIG group, one patient had tumours in both breasts. In two patients, we could not detect SLNs with lymphoscintigraphy, although they were detected with IGP and blue dye. We found SLNs for all tumours with IGP. With the intraoperative blue dye, SLNs were identified for 25 tumours; for one tumour, no SLN was detected with blue dye. In the histopathological examination, 13 tumours showed metastasis in the SLN and in 11 of these 13, there were also metastases in the axilla. One patient had a skip metastasis. In the Tc-99m nanocolloid group, SLNs were identified in 24 patients with lymphoscintigraphy. IGP found SLNs in 24 patients. The blue dye detected SLNs in all patients. On histopathological examination, 10 patients had metastasis in the SLN and there were also metastases in the axilla in all of these patients.

CONCLUSION

Tc-99m HIG can be used in SLN detection with preoperative lymphoscintigraphy and IGP in early-stage breast cancer patients.

Intradermal lymphoscintigraphy at rest and after exercise: a new technique for the functional assessment of the lymphatic system in patients with lymphoedema

AIM

The aim of this study was to evaluate the effect of implementing a new technique, intradermal injection lymphoscintigraphy, at rest and after muscular exercise on the functional assessment of the lymphatic system in a group of patients with delayed or absent lymph drainage.

METHODS

We selected 44 patients (32 women and 12 men; 15 of 44 with upper limb and 29 of 44 with lower limb lymphoedema). Thirty of 44 patients had bilateral limb lymphoedema and 14 of 44 had unilateral disease; 14 contralateral normal limbs were used as controls. Twenty-three patients had secondary lymphoedema after lymphadenectomy and the remaining 21 had idiopathic lymphoedema. Each of the 44 patients was injected with 50 MBq (0.3-0.4 ml) of (99m)Tc-albumin-nanocolloid, which was administered intradermally at the first interdigital space of the affected limb. Two planar static scans were performed using a low-energy general-purpose collimator (acquisition matrix 128 x 128, anterior and posterior views for 5 min), and in which drainage was slow or absent, patients were asked to walk or exercise for 2 min. A postexercise scan was then performed to monitor and record the tracer pathway and the tracer appearance time (TAT) in the inguinal or axillary lymph nodes.

RESULTS

The postexercise scans showed that (i) 21 limbs (15 lower and six upper limbs) had accelerated tracer drainage and tracer uptake in the inguinal and/or axillary lymph nodes. Two-thirds of these showed lymph stagnation points; (ii) 27 limbs had collateral lymph drainage pathways; (iii) in 11 limbs, there was lymph drainage into the deeper lymphatic channels, with unusual uptake in the popliteal or antecubital lymph nodes; (iv) six limbs had dermal backflow; (v) three limbs did not show lymph drainage (TAT=not applicable). TAT=15 + or - 3 min, ranging from 12 to 32 min in limbs with lymphoedema versus 5 + or - 2 min, ranging from 1 to 12 min in the contralateral normal limbs (P<0.001).

CONCLUSION

Intradermal injection lymphoscintigraphy gives a better imaging of the lymph drainage pathways in a shorter time, including cases with advanced lymphoedema. In some patients with lymphoedema, a 2-min exercise can accelerate tracer drainage, showing several compensatory mechanisms of lymph drainage. The effect of the exercise technique on TAT and lymphoscintigraphy findings could result in a more accurate functional assessment of lymphoedema patients.

Delivery of radiolabelled blood cells to lymphatic vessels by intradermal injection: a means of investigating lymphovenous communications in the upper limb

OBJECTIVE

To identify peripheral lymphovenous communications (LVCs) using labelled erythrocytes and intradermal injection. Intradermal injection delivers macromolecules to loco-regional lymph nodes faster than subcutaneous injection, suggesting easier lymphatic vessel access.

METHODS

Autologous erythrocytes labelled with 111In and 99mTc were injected into opposite hands. In four normal volunteers, the differentially labelled cells were given by intradermal injection on one side and subcutaneous injection on the other while in four breast cancer patients they were given by intradermal injection bilaterally 3 months after axillary lymph node clearance surgery. The axillae were imaged and blood samples obtained bilaterally at approximately 15, 30, 60, 120 and 180 min post-injection. Plasma activity was subtracted from whole blood activity to obtain erythrocyte-bound activity and contralateral concentrations were subtracted from ipsilateral concentrations to correct for ipsilateral recirculation. From estimated blood volume, erythrocyte and plasma activities contralateral to the injected side were calculated as percentage administered activity. Tracer concentrations in ipsilateral samples (%/l) were integrated to give total percentage administered activity, assuming a forearm blood flow of 20 ml/min.

RESULTS

Kinetics of plasma activity were consistent with small diffusible 99mTc complexes and protein-bound 111In. With both radionuclides, axillary nodes were visualized after intradermal but not subcutaneous injection, suggesting that nodal activity arises from erythrocytes. In one patient, 99mTc and 111In labelled erythrocytes accumulated in similar amounts ipsilaterally and contralaterally, suggesting bilateral LVCs distal to the ipsilateral sampling point. There was no evidence of LVCs in the other seven volunteers.

CONCLUSION

Intradermally injected erythrocytes are able to detect and potentially quantify peripheral LVCs.

Lymphatic drainage pathways of the breast and the upper limb

OBJECTIVE

To determine how often the sentinel lymph node (SLN) draining the breast is the same node as the SLN draining the upper limb. A common SLN might increase the risk of upper limb breast cancer-related lymphoedema after SLN biopsy.

METHODS

Patients with invasive breast cancer, identified as being suitable for axillary lymph node dissection, were injected preoperatively with 40 MBq of technetium-99m (Tc)-human polyclonal immunoglobulin G intradermally into the ipsilateral breast and 3 MBq of indium-111 (In)-human polyclonal immunoglobulin G intradermally into the ipsilateral hand, or vice versa. Axillary lymph nodes were removed, separated and assayed in a well counter for Tc and In.

RESULTS

Fifteen patients entered the study. In 13 of 15 patients, the 'hottest' lymph node for Tc was separate from the 'hottest' lymph node for In. In two of 15 patients the 'hottest' lymph node for Tc was also the 'hottest' lymph node for In, suggesting a common drainage pathway from the ipsilateral breast and upper limb.

CONCLUSION

Although the majority of patients has different pathways of lymphatic drainage from the ipsilateral breast and upper limb, in a small minority of patients the drainage pathway is through a common SLN. Such patients may be at increased risk of developing upper limb breast cancer-related lymphoedema after SLN biopsy.

Scintigraphic investigations of the superficial lymphatic system: quantitative differences between intradermal and subcutaneous injections

RATIONALE AND OBJECTIVES

Both subcutaneous and intradermal injections are used for the scintigraphic investigations of the superficial lymphatic system. The qualitative differences between these types of injections are well known. This study quantified their differences in a group of volunteers.

METHODS

With the limbs at rest, activities in the axillary nodes (AxN) were recorded at 1, 20, 40, 60, 80 and 100 min after subcutaneous or intradermal injection of TC-labelled human serum albumin nanocolloids in the ventral middle part of each forearm of nine young, healthy, male volunteers and the results were compared.

RESULTS

Expressed as per 10,000 of injected activity, activities recorded in the AxN were significantly higher (32.5 times as a mean value, ranging from 8.4 to 130.7 times) after intradermal injections than after subcutaneous injections (P<0.001 by using two-tailed Wilcoxon's signed-rank test). The mean AxN activity after intradermal injections was also apparently higher for the right limbs than for the left limbs, but when the paired t-test was used to compare the right with the left values of the nine volunteers, the comparison did not reach statistical significance (at T+100, 2P=0.087). When their handedness is taken into account, however, a level of statistical significance is reached (at T+100, 2P=0.025).

CONCLUSION

This study quantifies the differences between subcutaneous and intradermal injections, but also shows, although on a limited number of volunteers, that handedness influences the results of the intradermal injections.

A pilot study to assess the utility of SPECT/CT-based lymph node imaging to localize lymph nodes that drain the arm in patients undergoing treatment for breast cancer

Image-guided treatment planning that minimizes irradiation of critical lymph nodes (LNs) may reduce the incidence and severity of long term complications following breast cancer treatment. This localization cannot be obtained with conventional imaging techniques and we undertook this proof of concept study to determine whether a coordinated use of SPECT and CT has sufficient precision to inform radiation planning and potentially lessen the incidental exposure of critical LNs. Thirty-two consecutive women with breast cancer were injected in the arm ipsilateral to their breast cancers prior to radiation treatment with 0.5 mCi of filtered (99m)Tc-sulfur colloid and underwent scanning with a hybrid device which combined a dual-head SPECT camera and a low-dose, single slice CT scanner. The number of visualized LNs as well as their locations, maximum counts, and total uptake were recorded. Coordinates derived from the SPECT/CT fusion images were used to map LN locations onto the 3D radiation treatment planning system. A mean of 3.4 (SD 2.0) lymph nodes were detected in each subject. Level I and II LNs were detected more often in patients who had sentinel node biopsies, and more supraclavicular nodes were detected in patients who had undergone axillary dissection (P < 0.001). SPECT-CT derived LN coordinates were successfully mapped onto radiation simulation CT scans for all patients. SPECT/CT fusion images localize the LNs draining the arm after breast cancer surgery. These finding suggest that SPECT/CT may be helpful in minimizing incidental LN irradiation and in directing breast cancer therapy to reduce long-term morbidity.

Avaliação das compensações linfáticas no pós-operatório de câncer de mama com dissecção axilar através da linfocintilografia

O sistema linfático é um componente do corpo humano intimamente relacionado ao sistema venoso. Entretanto, o conhecimento científico a seu respeito é limitado. A etiologia e os fatores de risco para o desenvolvimento do linfedema no pós-operatório de câncer de mama são multifatoriais e ainda não foram completamente esclarecidos. O objetivo desta revisão da literatura foi descrever o padrão linfocintilográfico e avaliar as compensações linfáticas do membro superior no pós-operatório de câncer de mama com dissecção axilar.

Is there enhanced lymphatic function in upper body trained females?

BACKGROUND

Chronic physical activity results in adaptations in many aspects of human physiology, while specific training can directly influence structural changes. It remains unknown if habitual exercise influences upper extremity lymphatic function in females; thus, the purpose of this cross-sectional study was to compare different exercise stresses on lymphatic function in ten upper body trained females with ten untrained females.

METHODS AND RESULTS

Participants underwent a maximal upper body aerobic test on an arm crank ergometer before undergoing three randomly assigned lymphatic stress tests. Lymphoscintigraphy was used to quantify lymphatic function. (99m)Tc-antimony colloid was injected into the third web space of each hand, followed by 1 min spot views taken with a gamma-radiation camera. The maximal stress test required individuals to repeat their initial maximal exercise test. The subjects were then imaged every 10 min until 60 min were reached. The submaximal stress test involved arm cranking for 2.5 min at 0.6 W x kg(-1), followed by 2.5 min of rest, repeated for 60 min. The final stress test was a 60 min seated resting session. The clearance rate (CR) and axillary uptake (AX) were determined. Only AX post maximal exercise was significantly different between trained and untrained, p=0.009. All other measures of lymphatic function between groups were similar.

CONCLUSION

This study demonstrates no significant difference in lymphatic function between upper body trained and untrained females.

Human lymphatic pumping measured in healthy and lymphoedematous arms by lymphatic congestion lymphoscintigraphy

Axillary surgery for breast cancer partially obstructs lymph outflow from the arm, chronically raising the lymphatic smooth muscle afterload. This may lead to pump failure, as in hypertensive cardiac failure, and could explain features of breast cancer treatment-related lymphoedema (BCRL) such as its delayed onset. A new method was developed to measure human lymphatic contractility non-invasively and test the hypothesis of contractile impairment. 99mTc-human IgG (Tc-HIG), injected into the hand dermis, drained into the arm lymphatic system which was imaged using a gamma-camera. Lymph transit time from hand to axilla, ttransit, was 9.6+/-7.2 min (mean+/-s.d.) (velocity 8.9 cm min(-1)) in seven normal subjects. To assess lymphatic contractility, a sphygmomanometer cuff around the upper arm was inflated to 60 mmHg (Pcuff) before 99mTc-HIG injection and maintained for>>ttransit. When Pcuff exceeded the maximum pressure generated by the lymphatic pump (Ppump), radiolabelled lymph was held up at the distal cuff border. Pcuff was then lowered in 10 mmHg steps until 99mTc-HIG began to flow under the cuff to the axilla, indicating Ppump>or=Pcuff. In 16 normal subjects Ppump was 39+/-14 mmHg. Ppump was 38% lower in 16 women with BCRL, namely 24+/-19 mmHg (P=0.014, Student's unpaired t test), and correlated negatively with the degree of swelling (12-56%). Blood radiolabel accumulation proved an unreliable measure of lymphatic pump function. Lymphatic congestion lymphoscintigraphy thus provided a quantitative measure of human lymphatic contractility without surgical cut-down, and the results supported the hypothesis of lymphatic pump failure in BCRL.

Blue Dye Injection in the Arm in Order to Conserve the Lymphatic Drainage of the Arm in Breast Cancer Patients Requiring an Axillary Dissection

BACKGROUND

Despite the widespread use of the sentinel lymph node biopsy technique, many patients with invasive breast cancer still undergo an axillary lymph node dissection and are at risk of arm lymphedema. With the new awareness of lymphatic spread in the axillary nodes, it should be possible to define a new surgical approach between sentinel lymph node biopsy and complete axillary dissection, a procedure preserving specifically lymph nodes in relation to the arm.

METHODS

Twenty-one patients with an operable breast cancer requiring an axillary dissection underwent surgery with an attempt to separate nodes related to the breast from specific nodes related to the arm. After an injection of blue dye in the arm, the surgeon performed the axillary dissection trying to identify blue nodes and ducts in order to preserve lymphatic arm drainage (LAD). If the blue nodes were located in the normal axillary dissection, they were removed separately.

RESULTS

In 15 of 21 patients (71%), blue nodes in relation with LAD were identified. In 10 (47%) patients, it was possible to dissect the LAD with the preservation lymphatic ducts. In 10 patients, the LAD nodes were removed: none of them contained metastases, despite the fact that the non-LAD axillary nodes contained metastases in 7 of 10 cases.

CONCLUSIONS

Identifying the LAD with blue dye injection in the arm is possible. A subsequent study can now begin to determine if this procedure is safe for patients and able to prevent lymphedema of the arm.

Lymphatic transfer studies with immunoglobulin scintigraphy after axillary surgery

AIMS

The study objective was to investigate the effects of axillary lymph node clearance surgery on the function and morphology of the lymphatic system of the upper limb in women with breast cancer.

METHODS

Nineteen women were studied before and 3 months after surgery. Fifteen were studied again 12 months after surgery. On each occasion, scintigraphy following intradermal hand webspace injection of Tc-99m-human polyclonal immunoglobulin was performed to include the affected upper limb and torso.

RESULTS

There was considerable functional variability in response to surgery. Seven patients subsequently developed breast cancer-related lymphedema (BCRL). Neither lymph re-routing (defined as a change in lymph vessel morphology or definition) nor linear velocity of protein transit up the arm was associated with the development of BCRL. Blood pool activity, judged from visual inspection of the cardiac blood pool on the whole body images, was earlier and more marked 3 and 12 months after surgery than before. The count rate (per 100 pixels/MBq injected activity), measured in a cardiac region of interest, was significantly higher after surgery than before, was higher in patients who developed BCRL and, in the patient population as a whole, correlated positively with arm swelling.

CONCLUSION

The consequences of axillary lymph node clearance were variable, unexpected and largely persistent. An increased rate of access of intradermally injected protein into the blood pool is significantly associated with BCRL.

Quantitative imaging of lymph function

Functional lymphatic imaging was demonstrated in the abdomen and anterior hindlimb of anesthetized, intact Yorkshire swine by using near-infrared (NIR) fluorescence imaging following intradermal administration of 100-200 microl of 32 microM indocyanine green (ICG) and 64 microM hyaluronan NIR imaging conjugate to target the lymph vascular endothelial receptor (LYVE)-1 on the lymph endothelium. NIR fluorescence imaging employed illumination of 780 nm excitation light ( approximately 2 mW/cm(2)) and collection of 830 nm fluorescence generated from the imaging agents. Our results show the ability to image the immediate trafficking of ICG from the plexus, through the vessels and lymphangions, and to the superficial mammary, subiliac, and middle iliac lymph nodes, which were located as deep as 3 cm beneath the tissue surface. "Packets" of ICG-transited lymph vessels of 2-16 cm length propelled at frequencies of 0.5-3.3 pulses/min and velocities of 0.23-0.75 cm/s. Lymph propulsion was independent of respiration rate. In the case of the hyaluronan imaging agent, lymph propulsion was absent as the dye progressed immediately through the plexus and stained the lymph vessels and nodes. Lymph imaging required 5.0 and 11.9 microg of ICG and hyaluronan conjugate, respectively. Our results suggest that microgram quantities of NIR optical imaging agents and their conjugates have a potential to image lymph function in patients suffering from lymph-related disorders.

Imaging of lymphatic vessels in breast cancer-related lymphedema: intradermal versus subcutaneous injection of 99mTc-immunoglobulin

OBJECTIVE

The disordered physiology that results from axillary lymph node clearance surgery for breast cancer and that leads to breast cancer-related lymphedema is poorly understood. Rerouting of lymph around the axilla or through new pathways in the axilla may protect women from breast cancer-related lymphedema. The aim of the study was to compare intradermal with subcutaneous injection of technetium-99m ((99m)Tc)-labeled human polyclonal IgG (HIG) with respect to lymphatic vessel imaging.

MATERIALS AND METHODS

Six women with breast cancer-related lymphedema underwent unilateral upper limb lymphoscintigraphy, using a web space injection of (99m)Tc-labeled HIG, after intradermal and subcutaneous injections on separate occasions. Multiple sequential images were obtained of the affected upper limb and torso over 3 hr on each occasion. Accumulation of activity in blood was quantified from venous blood samples taken from the opposite arm.

RESULTS

Imaging after intradermal injection clearly showed discrete lymphatic vessels in five of six patients, in contrast to imaging after subcutaneous injection, which did not show any discrete vessels in any patient. Intradermal injection resulted in more rapid visualization of cutaneous lymph rerouting than subcutaneous injection in six of six patients. Recovery of injected (99m)Tc-labeled HIG in venous blood was greater after intradermal injection in six of six patients.

CONCLUSION

In patients with breast cancer-related lymphedema, lymphatic vessels are more clearly depicted after intradermal than subcutaneous injection as a result of direct access of radiotracer to dermal lymphatics. This finding has implications for imaging lymphatic vessel regeneration and lymph rerouting.

A quantitative lymphoscintigraphic evaluation of lymphatic function in the swollen hands of women with lymphoedema following breast cancer treatment

In BCRL (breast cancer-related lymphoedema), arm swelling is unevenly distributed and some regions are partly or entirely spared. In particular, the hand may or not be swollen, but when involved functional impairment can be substantial. We have found previously that, when the ipsilateral hand is spared of swelling (in a limb with swelling proximal to the hand), the local lymph drainage rate constant (k) is at least as high as in the contralateral hand, contrary to the traditional 'stopcock' concept of reduced lymph drainage from the whole limb. In the light of this finding, we have investigated lymph drainage in the hands of eight women with BCRL and moderate-to-severe hand swelling, using gamma-camera quantitative lymphoscintigraphy. Images showed pronounced superficial activity in the ipsilateral swollen arms of most patients, indicating dermal backflow. k for 99mTc-labelled hIgG (human IgG) measured over 5 h in the subcutis of the ipsilateral swollen hand was 34+/-24% less than in the contralateral hand (P=0.013). Activity measured in the ipsilateral swollen forearm increased progressively, but there was very little increase in the contralateral forearm, indicating retention of 99mTc-labelled hIgG in the swollen forearm. It is concluded that lymphatic function in the swollen hand is impaired, and that there appears to be two populations of women with BCRL, i.e. spared-hand and swollen-hand, irrespective of the cancer treatment received.

The efficacy of 99mTc-HIG for sentinel lymph node mapping in breast cancer patients

OBJECTIVE

To evaluate the efficacy of Tc-HIG on SLN identification in patients with early-stage breast cancer.

MATERIALS AND METHODS

Seventeen women (18 tumours) with early-stage breast cancer were included. On the day of the operation, 111 MBq Tc-HIG was injected around the tumour or biopsy scar in all patients. Subsequently, dynamic lymphoscintigraphic images were taken for 30 min. After this, static images were recorded at 15-20 min intervals until the SLN was visualized. Patients were taken to the operating room 2-4 h after radiopharmaceutical injection. Before the incision, 5 ml of isosulfan blue dye solution was injected peritumourally in all subjects. Aided by blue dye and gamma probe SLN detection was done during the operation.

RESULTS

In 17/18 tumours, SLN was detected with Tc-HIG lymphoscintigraphy. The mean visualization time for axillary SLNs was 49.94+/-11.25 min and for internal mammary SLNs was 52.50+/-10.60 min. In 15 of the tumours, only one SLN was detected in the axillary region. However, in two tumours, SLNs were found in both axillary and internal mammary regions. With blue dye mapping, axillary SLNs were found in 17/18 tumours. With the application of intraoperative gamma probe, all axillary and internal mammary SLNs were detected in 18 tumours.

CONCLUSION

We conclude that Tc-HIG may be a suitable agent for SLN detection by lymphoscintigraphy and intraoperative gamma probe application in early-stage breast cancer patients.