Popliteal node visualization during standard pedal lymphoscintigraphy for a swollen limb indicates impaired lymph drainage

Surgical Management of Central Lymphatic Conduction Disorders: A Review

AIM

Recent advances in lymphatic imaging allow understanding the pathophysiology of lymphatic central conduction disorders with great accuracy. This new imaging data is leading to a wide range of novel surgical interventions. We present here the state-of-the-art imaging technology and current spectrum of surgical procedures available for patients with these conditions.

METHOD

Descriptive report of the newest lymphatic imaging technology and surgical procedures and retrospective review of outcome data.

RESULTS

There are currently two high-resolution imaging modalities for the central lymphatic system: multi-access dynamic contrast-enhanced MR lymphangiogram (DCMRL) and central lymphangiography (CL). DCMRL is done by accessing percutaneously inguinal and mesenteric lymph nodes and periportal lymphatics vessels. DCMRL provides accurate anatomical and dynamic data on the progression, or lack thereof, of the lymphatic fluid throughout the central lymphatic system. CL is done by placing a catheter percutaneously in the thoracic duct (TD). Pleural effusions are managed by pleurectomy and intraoperative lymphatic glue embolization guided by CL. Anomalies of the TD are managed by TD-to-vein anastomosis and/or ligation of aberrant TD branches. Chylous ascites and organ-specific chylous leaks are managed by intraoperative glue embolization, surgical lymphocutaneous fistulas, and ligation of aberrant peripheral lymphatic channels, among several other procedures.

CONCLUSION

The surgical management of lymphatic conduction disorders is a new growing field within pediatric general surgery. Pediatric surgeons should be familiar with the newest imaging modalities of the lymphatic system and with the surgical options available for patients with these complex surgical conditions to provide prompt treatment or referral.

LEVEL OF EVIDENCE

V.

Quantitative lymphoscintigraphy of the lower limbs for the diagnosis of phlebolymphoedema

INTRODUCTION

Phlebolymphoedema is caused by the interaction of the venous and lymphatic systems in a state of chronic venous insufficiency in which increased microvascular filtration causes an increased rate of lymph production. Lymphatic drainage rate increases in response, but this is unsustainable and can cause lymphatic failure and oedema. We hypothesise that in phlebolymphoedema we could measure unusually high lymphatic drainage while the lymph system is still fully functional.

METHOD

Patients referred for lymphoscintigraphic investigation of swollen legs between April 2021 and December 2022 were reviewed. Quantitative lymphoscintigraphy was performed following the technique of Keramida et al . (2017) and ilio-inguinal nodal uptake (IIQ%) was calculated. The presence of scintigraphic features of increased lymph production was noted for each limb.

RESULTS

A total of 39 patients were reviewed (78 limbs, 29F, 10M). Seven limbs were identified with supranormal lymphatic function (IIQ > 30%) plus three borderline. Of these 10 limbs, all had at least two scintigraphic features of increased lymph production.

CONCLUSION

Quantitative lymphoscintigraphy, although developed for diagnosing abnormally low lymphatic function, may also have utility at the upper end of the spectrum for identifying chronic venous insufficiency. An IIQ% upper normal limit of 30% could be used to diagnose venous insufficiency as the cause for limb swelling. This is of note for patients of large body habitus in whom venous ultrasound is difficult.

PIEZO1-gene gain-of-function mutations with lower limb lymphedema onset in an adult: Clinical, scintigraphic, and noncontrast magnetic resonance lymphography findings

Primary lymphedema, a rare disease, has a genetic cause in ~40% of patients. Recently, loss-of-function mutations in PIEZO1, which encodes the mechanotransducer protein PIEZO1, were described as causing primary lymphedema, when gain-of-function PIEZO1 mutations were attributed to dehydrated hereditary stomatocytosis type-1 (DHS), a dominant red cell hemolytic disorder, with ~20% of patients having perinatal edema. Lymphedema was diagnosed in a 36-year-old man from a three-generation DHS family, with a PIEZO1-allele harboring 3 missense mutations in cis. Four affected family members had severe fetal and neonatal edema, most severe in the proband, whose generalized edema with prevailing ascites resolved after 8 months. Our patient's intermittent lower limb-lymphedema episodes during hot periods appeared at puberty; they became persistent and bilateral at age 32. Clinical Stemmer's sign confirmed lymphedema. Lower leg lymphoscintigraphy showed substantial dermal backflow in both calves, predominantly on the right. Noncontrast magnetic resonance lymphography showed bilateral lower limb lymphedema, dilated dysplastic lymphatic iliac, and inguinal trunks. Exome-sequencing analysis identified no additional pathogenic variation in primary lymphedema-associated genes. This is the first description of well-documented lymphedema in an adult with PIEZO1-DHS. The pathophysiology of PIEZO1-associated primary lymphedema is poorly understood. Whether it infers overlapping phenotypes or different mechanisms of gain- and loss-of-function PIEZO1 mutations deserves further investigation.

Analysis of collateral lymphatic circulation in patients with lower limb lymphedema using magnetic resonance lymphangiography

OBJECTIVE

Although the development of lymphatic collaterals is expected following lymphedema, little is known about the anatomic details of such compensatory pathways or their association with symptoms. Magnetic resonance lymphangiography (MRL) has been shown to be superior to lymphoscintigraphy and indocyanine green lymphography in visualizing lymphatics. This study aimed to analyze MRL images of lower limbs to elucidate the patterns of lymphatic collateral formation and their association with the clinical stages of lymphedema.

METHODS

We enrolled 56 consecutive patients (112 lower limbs) with lymphedema who underwent MRL. Two radiologists performed a consensus reading of MRL images for the presence or absence of collateral lymphatic pathways, and the results were compared with the clinical stages. Furthermore, the frequency of abnormal MRL findings in 43 asymptomatic lower limbs of patients with unilateral lymphedema was analyzed and compared with that in the 69 symptomatic lower limbs of the patients. The imaging findings were also compared with the cause of lymphedema.

RESULTS

All three collateral pathways (anterolateral, deep, and posteromedial lymphatics) were visualized at a higher (P < .05) frequency in stage II than in stage 0 lower limbs. The frequency of visualization of the three collaterals was significantly higher in symptomatic (stages I-III) lower limbs than in asymptomatic (stage 0) lower limbs. Most (76.8%) of the symptomatic limbs exhibited at least one of these collaterals, and the frequency was significantly higher than in the asymptomatic limbs (P < .001). Most (81.4%) of the asymptomatic (stage 0) lower limbs had at least one abnormal finding in terms of lymphatic circulation, although this proportion was significantly lower compared with the symptomatic limbs (98.6%). The collaterals tended to appear less frequently in primary lymphedema than in secondary lymphedema, reaching statistical significance in the posteromedial lymphatics.

CONCLUSIONS

These results suggested that the two superficial lymphatic groups and the deep lymphatic system act as major collaterals of the lower limbs in patients with lymphedema. Furthermore, MRL of most patients with unilateral lymphedema demonstrated abnormal findings, including collateral formation, not only in the affected lower limb but also in the asymptomatic lower limb. In primary lymphedema, the collaterals may appear less frequently than in secondary lymphedema. Collaterals should be taken into consideration in planning the site of lymphaticovenous anastomosis and assessing disease progression. MRL can visualize preclinical alterations in lymphatic flow and compensatory pathways; therefore, we expect that it will be useful for the early diagnosis of lymphedema.

Clinical and Scintigraphic Predictors of Primary Lower Limb Lymphedema-Volume Reduction During Complete Decongestive Physical Therapy

BACKGROUND

Primary lower limb lymphedema is a chronic debilitating disorder without curative treatment. The initial treatment phase is dedicated to reducing lymphedema volume, whereas the second aims to stabilize that volume.

OBJECTIVE

The objective of this study was to analyze clinical and lymphoscintigraphic characteristics during complete decongestive physical therapy as predictors of primary unilateral lower limb lymphedema-volume reduction.

DESIGN

This observational, retrospective study included 222 consecutive patients (January 2009-January 2017; median age: 45.8 years) with lymphedema affecting the entire lower limb, who received complete decongestive physical therapy for the first time in a specialized lymphedema management center.

METHODS

Complete decongestive physical therapy consisted of low-stretch bandaging, manual lymph drainage, exercises, and skin care for all patients. Lymphoscintigraphy preceded treatment.

RESULTS

Median lymphedema evolution was 73 months, and median excess volume was 34%. Median (interquartile range) lymphedema volumes were 2845 (1038-3487) mL before and 1276 (601-2195) mL after a median of 11 days of complete decongestive physical therapy, with 34% median reduction. Multivariate analyses retained age, body mass index >40 kg/m2, and previous cellulitis, as independently associated with lymphedema volume reduction. For each additional year of age, volume reduction increased 0.16%. Unexpectedly, log-transformed initial lymphedema volumes indicated a negative impact, that is, 4.95%, for each log-unit gain. Patients with previous cellulitis episode(s) obtained 6.9% and those with BMI >40 kg/m2 17.1% higher lymphedema volume reductions. Lower limb lymphoscintigraphy was available for 150 (67.6%) patients. Having dermal back flow was associated with greater lymphedema volume reduction than not (respectively, 39% vs 31%).

LIMITATIONS

This study was retrospective, and only 67.6% of patients underwent lymphoscintigraphy.

CONCLUSION

Our analysis identified clinical and scintigraphic predictors of primary lymphedema volume reduction for patients with unilateral disease. Lymphoscintigraphy helps confirm lymphedema and predict volume reduction. Further study is required to confirm these observations.

Staging and clinical correlations of lymphoscintigraphy for unilateral gynecological cancer-related lymphedema

BACKGROUND

This study was to investigate the lymphoscintigraphy findings for the diagnosis and severity in unilateral gynecological cancer-related lymphedema (GCRL) and to correlate lymphoscintigraphy stages with the clinical findings.

METHODS

Patients with unilateral GCRL who underwent lymphoscintigraphy were staged using the presence of ileo-inguinal lymph nodes, distal-lymphatic ducts, and dermal backflow findings. Taiwan Lymphoscintigraphy Staging (TLS) was divided into three patterns and seven stages: normal drainage (L-0); partial obstruction (P-1, P-2, and P-3); and total obstruction (T4, T-5, and T-6). Correlations between clinical lymphedema severity and TLS were evaluated using analysis of variance and multivariable linear regression analyses.

RESULTS

A total of 141 patients with unilateral GCRL were divided as follows: 6 (4.3%) in normal drainage, 56 (39.7%) in partial-obstruction, and 79 (56%) in total obstruction. Cellulitis episodes, circumferential difference, and computed tomography (CT) volumetric difference were shown to be statistically different between TLS stages (P < .001 for all). Total obstruction stages were the most significant factors associated with the severity of circumferential difference (β = 19.72, 25.54, 32.42, respectively; P < .05) and CT volumetric difference (β = 36.04, 45.12, 52.78, respectively; P < .01).

CONCLUSIONS

Total lymphatic obstruction was present in 56% of unilateral GCGL. Lymphoscintigraphy stages were statistically correlated with episodes of cellulitis, circumferential difference and CT volumetric difference in unilateral GCRL.

Scintigraphic Investigations of the Deep and Superficial Lymphatic Systems in the Evaluation of Lower Limb Oedema

The lymphoscintigraphic investigation (LySc) of the superficial lymphatic system (SLS) remains the gold standard for the diagnosis of lower limb lymphoedema. However, LySc of the deep lymphatic system (DLS) may be useful for diagnosing deep lymphatic system insufficiency in patients with lower limb oedema (LLE) but normal and/or paradoxical LySc of the SLS. The purpose of this study was therefore to evaluate a new LySc of the deep lymphatic system in patients presenting with a normal and/or paradoxical SLS exam showing LLE. In all, 15 patients with unilateral and 17 with bilateral LLE underwent 3-phased deep LySc of the lower limb via the injection of 99 mTc-labelled human serum albumin (HSA) nanocolloids in the Kager’s triangle. The absence of popliteal lymphatic node visualization after phase 2 of DLS LySc to diagnose a deep lymphatic insufficiency has a specificity and a sensitivity of 89% in patients with unilateral LLE and without associated venous symptoms. An insufficiency of the DLS was observed in 67% of cases with unilateral LLE and 59% of patients with bilateral LLE of venous and/or lymphatic origin. In conclusion, the lymphoscintigraphic visualization of the popliteal lymphatic nodes after the injection of 99 mTc-labelled HSA nanocolloids in the Kager’s triangle seems to be an effective way to diagnose DLS insufficiency in patients with LLE but normal findings in the SLS.

Lymphatic drainage efficiency: a new parameter of lymphatic function

Background Following convection from blood capillaries, plasma proteins are transported to loco-regional lymph nodes in two stages: first, uptake into peripheral lymphatics, and second, transport to nodes. Purpose To introduce a new parameter of lymphatic function that quantifies stage 2 - lymphatic drainage efficiency (LDE). Material and Methods Percentage injected activity (IIQ) in ilio-inguinal nodes 150 min following subcutaneous foot web-space injection of Tc-99 m-nanocolloid was measured in 102 patients undergoing lymphoscintigraphy using a method in which a standard is placed by image guidance over the nodes. Percentage activity leaving the injection depot by 150 min ( k) was measured in 60/102 patients. LDE (%) = 100 × (IIQ/ k). Abnormal lymphoscintigraphy was defined qualitatively as: (i) no activity in ilio-inguinal nodes at 45 min or negligible activity at 150 min (delay); (ii) lymph diversion through skin and/or deep system; and (iii) focal tracer accumulation suggesting cellulitis. Results Scintigraphy was bilaterally normal in 82 limbs, unilaterally normal in 40 limbs and abnormal in 82 limbs. IIQ correlated with k in bilaterally normal (r = 0.86; n = 52), unilaterally normal (r = 0.67; n = 27), and abnormal (r = 0.82; n = 41) limbs. IIQ, k, and LDE were significantly lower in unilaterally normal (9.3 ± 5.4%, 13.8 ± 7.1%, and 65 ± 30%) compared with bilaterally normal limbs (15.4 ± 8.4% [ P > 0.0001], 18.3 ± 8.9% [ P = 0.025], and 84 ± 30% [ P = 0.01]). LDE was lower in limbs displaying skin diversion and/or delay. Conclusion LDE is a new quantitative index that has potential value in clinical research but requires further clinical evaluation. Abnormal quantitative indices indicate that limbs unilaterally normal on lymphoscintigraphy are not functionally normal.

[Primary lymphedema in childhood]

Lymphedema results from impaired lymphatic transport with increased limb volume and is divided into primary and secondary forms. In children, primary lymphedema is the most frequent, with a sporadic, rarely familial form or associated with complex malformative or genetic disorders. Diagnosis of lymphedema is mainly clinical and lymphoscintigraphy is useful to assess the lymphatic function of both limbs precisely. The main differential diagnosis is overgrowth syndrome. Erysipelas (cellulitis) is the main complication, but psychological or functional discomfort may occur throughout the course of lymphedema. Lymphedema management is based on multilayer low-stretch bandage, skin care, and eventually manual lymph drainage. The objective of treatment is to reduce lymphedema volume and then stabilize it. Multilayer low-stretch bandage and elastic compression are the cornerstone of treatment. Parent's motivation, including self-management, is required to ensure the child's compliance and improve quality of life.

Lymphoscintigraphic abnormalities in the contralateral lower limbs of patients with unilateral lymphedema

OBJECTIVE

The contralateral limbs of patients with unilateral lymphedema in the lower limbs (LLs) can exhibit abnormal lymphatic circulation, even in the absence of lymphedema. This idea is based on a number of reports that have studied isolated cases using lymphoscintigraphy. It is likely that these patients previously had some form of lymphopathy, and the lymphedema arose after the action of some external factor. However, there are no studies in the literature that adequately assess the asymptomatic contralateral limbs of these patients or address the prevalence and characteristics of the abnormal lymphatic circulation in these limbs. The aim of this study was to assess the prevalence of abnormal lymphatic circulation in the asymptomatic contralateral limbs of patients with unilateral lymphedema of the LL.

METHODS

Forty-three patients from the angiology and vascular surgery ward of the Hospital das Clínicas da Universidade Federal de Pernambuco with unilateral lymphedema of the LL underwent lymphoscintigraphy. All patients received a subcutaneous injection of 0.2 mL (74 MBq) of a solution of dextran 70 labeled with technetium Tc 99m in the first interdigital space of each foot. Images were obtained on two occasions: 10 minutes and 1 hour after the injection. The study design was transversal prospective.

RESULTS

Among the 43 asymptomatic LLs, 30 (70%) showed abnormal lymphatic circulation. The lymphoscintigraphic abnormalities found were the following: reduced visualization of the lymphatic vessels and lymph nodes during 1 hour (83%), collateral circulation (30%), visualization of the inguinal and pelvic lymph nodes after at least 1 hour (30%), visualization of the popliteal lymph nodes (20%), dilation and lymphatic tortuosity (20%), and dermal backflow (10%).

CONCLUSIONS

In this study,70% of the patients with unilateral lymphedema of the LL had some form of lymphopathy in the contralateral limb during the lymphoscintigraphic examination. These findings could favor the early treatment of these patients to prevent the disease from progressing to its most severe stage.

Clinical Significance of Lymphoscintigraphy Findings in the Evaluation of Lower Extremity Lymphedema

OBJECTIVE

The purpose of this study was to investigate the clinical significance of lymphoscintigraphy imaging in the evaluation of lower extremity lymphedema.

METHODS

Technetium-99m-labeled nanocolloid was injected subcutaneously in the first web spaces of both feet of 123 patients (M/F: 43/80, mean age 57.5±13.1 years, range 16-78 years) who had clinical evidence of lower extremity swelling with suspicion of lymphedema, and were referred for routine lymphoscintigraphy. Lymphoscintigraphy scan was started as dynamic viewing followed by static whole body imaging at 10 minute, 1 hour and 4 hours after injection.

RESULTS

Eighty-seven patients had lymphedema. Patients who had lymphedema were divided into two groups according to their scintigraphy findings: Group I included 58 patients without uptake in the popliteal nodes, and group II included 29 patients with positive popliteal nodes. The rate of popliteal node visualization was higher in patients with dermal backflow as compared to those without dermal backflow (p<0.001). The duration of lymphedema was also longer in patients with dermal backflow and popliteal nodes (p<0.004).

CONCLUSION

Lymphoscintigraphy is a reliable, easily applied and well-tolerated objective method to diagnose lower extremity lymphedema. Uptake by popliteal lymph nodes and the presence of dermal backflow on lymphoscintigraphy, which is performed for evaluation of the lower limb lymphedema, were important signs indicating longer disease duration and higher severity of lymphatic dysfunction.

Novel mutations in PIEZO1 cause an autosomal recessive generalized lymphatic dysplasia with non-immune hydrops fetalis

Generalized lymphatic dysplasia (GLD) is a rare form of primary lymphoedema characterized by a uniform, widespread lymphoedema affecting all segments of the body, with systemic involvement such as intestinal and/or pulmonary lymphangiectasia, pleural effusions, chylothoraces and/or pericardial effusions. This may present prenatally as non-immune hydrops. Here we report homozygous and compound heterozygous mutations in PIEZO1, resulting in an autosomal recessive form of GLD with a high incidence of non-immune hydrops fetalis and childhood onset of facial and four limb lymphoedema. Mutations in PIEZO1, which encodes a mechanically activated ion channel, have been reported with autosomal dominant dehydrated hereditary stomatocytosis and non-immune hydrops of unknown aetiology. Besides its role in red blood cells, our findings indicate that PIEZO1 is also involved in the development of lymphatic structures.

Primary lymphoedema can lead to the swelling of the extremities and facial dysmorphism. Here the authors present evidence that compound heterozygous and homozygous mutations in PIEZO1 result in an autosomal recessive form of generalised lymphatic dysplasia.

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.

Growth plate uptake of Tc-99m-phytate on lymphoscintigraphy images

We report two pediatric cases with the history of lower extremity edema who were referred to the nuclear medicine department for lower limb lymphoscintigraphy as lymphedema workup. Subcutaneous injection of Tc-99m phytate in the interdigital webs was used for both patients, followed by early and delayed whole body lymphoscintigraphy imaging. Images of both patients showed Tc-99m phytate accumulation in the growth plates of the lower limbs. This biodistribution could interfere with popliteal lymph node visualization and should always be taken into account in lymphoscintigraphy of pediatric patients. We also review the medical literature regarding biodistribution Tc-99m phytate after interstitial injections.

Significance of popliteal lymph nodes visualization during radionuclide lymphoscintigraphy for lower limb lymphedema

Purpose:

To examine the frequency and significance of visualization of popliteal nodes during lymphoscintigraphy for the investigation of lower extremity swelling.

Materials and Methods:

Technetium-99m-labeled nanocolloid was injected subcutaneously in the first web spaces of both feet of 90 patients (24 males, 66 females; age range, 4-70 years) who had clinical evidence of lower limb lymphedema and were referred for routine lymphoscintigraphy; imaging was performed 5, and 90 minutes after injection without any vigorous exercise between the injection and imaging.

Results:

According to the scan findings, patients were divided into two groups; group I included 63 patients without popliteal nodes visualization on scanning, and group II included 27 patients with positive popliteal nodes uptake. None of patients with primary lymphedema (N = 22) due to agenesis or hypoplasia showed popliteal node uptake, whereas, patients with secondary lymphedema (N = 68) had either severe (N = 23) or partial (N = 45) lymphatic obstruction. A high positive association of popliteal node uptake with the severity of lymphatic obstruction was noted. Popliteal nodes were visualized in 26 of 57 patients with dermal back flow (46%), and in only 1 of 33 patients without dermal back flow (3%). There was a strong association between skin rerouting and popliteal node visualization (P < 0.01). Skin changes were detected in 24 patients (38%) with positive popliteal node uptake.

Conclusion:

Popliteal lymph nodes uptake during lymphoscintigraphy for clinical lymphedema of the lower limb indicates lymph rerouting through the deep system and raises a diagnosis of higher severity and longer duration of lymphatic dysfunction.

Peripheral lymphovenous communication in lymphoedema

AIM

To investigate whether in lower extremity lymphoedema, lymph proteins enter blood before they do the thoracic duct.

METHODS

Retrospective analysis of routine lymphoscintigraphy in 69 adults imaged at 5, 45 and 150 min following bilateral subcutaneous web space injection of Tc-nanocolloid was carried out. Regions of interest were placed over the liver and ilioinguinal lymph nodes bilaterally on the anterior images at 45 and 150 min. Individual minor (0.5 point for each) and major (1 point for each) criteria of abnormal scintigraphy were applied to each limb and summed to give a lymphoscintigraphic abnormality score. An abnormal limb had a score ≥1.

RESULTS

The ratio of hepatic counts per pixel to total bilateral ilioinguinal counts (L/N ratio) was higher in patients with abnormal results on lymphoscintigraphy (median 6.2; interquartile range 4.0-15.6 pixels×10; n=48) compared with that in patients with normal lymphoscintigraphic results (2.5 [1.5-5.0] pixels×10; n=21; P<0.0002). In the abnormal group, the lymphoscintigraphic score (two limbs summed) correlated with the 150-min L/N ratio (r s=0.42; P<0.005). L/N ratios at 45 and 150 min correlated in the abnormal group (r s=0.44; P<0.005) but not in the normal group (r s=0.3; P>0.05). The 45-min activity, as a percentage of the 150-min activity, was higher in lymph nodes than in the liver in both the abnormal (35.0 [8.2-50.0] vs. 10.6 [5.8-30.0]%; P<0.0001]) and normal groups (38.3 [18.4-63.5] vs. 23.3 [12.4-33.1]%; P<0.05), and, with respect to the liver, was higher in the normal group (P<0.01).

CONCLUSION

In lymphoedema, more lymph proteins enter blood proximal to the thoracic duct. The time courses of nodal and hepatic activities suggest that access may occur within nodes themselves.