Measurement Properties of Instruments for Measuring of Lymphedema: Systematic Review

Reliability and precision of single frequency bioelectrical impedance assessment of lower extremity swelling following total knee arthroplasty

Total knee arthroplasty (TKA) is the most common elective orthopedic surgery performed in the United States. Following surgery patients experience significant lower extremity swelling that is related to poor satisfaction with surgery and is hypothesized to contribute to functional decline. However, in practice, precise and reliable methods for measuring lower extremity swelling do not exist. The purpose of this study was to provide reliability and precision parameters of an innovative approach, single frequency bioelectrical impedance assessment (SF-BIA), for measuring post-TKA lower extremity swelling. Swelling in 56 patients (64.3 ± 9.3 years; 29 males) was measured before and after TKA using SF-BIA and circumferential measures (CM). Reliability of the measures was calculated using Intraclass Correlation Coefficients (ICC). Precision of the measures was provided using standard error of the measurement and minimal detectable change (MDC90). Change values between time points for SF-BIA and CM are provided. SF-BIA was found to have greater reliability following surgery compared to CM (ICC = 0.99 vs 0.68). SF-BIA was found to have an MDC90 = 2% following surgery, indicating improved ability to detect minute fluctuations in swelling compared to CM (MDC90 = 6%) following surgery. These results indicate that SF-BIA improves the precision and reliability of swelling measurement compared to CM.

The relationship between lower extremity swelling, quadriceps strength, and functional performance following total knee arthroplasty

BACKGROUND

The relationships between swelling after total knee arthroplasty (TKA) and quadriceps strength and functional performance are poorly understood. Therefore, the aim of this study was to examine the relationships between lower extremity swelling, measured using bioelectrical impedance assessment (SF-BIA), and quadriceps strength and timed up and go (TUG) times following TKA.

METHODS

53 participants (64 ± 9.5 y/o, 43% male) undergoing primary unilateral TKA were recruited for the longitudinal observational study with repeated measures. Quantities of swelling were examined for contribution to two and six-week outcomes of strength and TUG time using hierarchical regression controlling for age, sex, and the baseline value of the dependent variable. Swelling was assessed using bioelectrical impedance assessment and quantified as the peak level of swelling and cumulative swelling (integral) over the post-TKA time window. Maximum isometric quadriceps strength (MVIC) was measured using a electromechanical dynamometer and participant functional performance measured using the TUG.

RESULTS

Neither peak swelling nor cumulative swelling significantly contributed to the variance of two-week quadriceps strength. At six weeks, peak swelling significantly improved the variance in maximal quadriceps strength by an additional four percent (p = 0.05), while cumulative swelling did not significantly contribute. Peak swelling significantly contributed to the variance in two-week (16%) and six-week (five percent) TUG times (p < 0.05), but the cumulative swelling did not.

CONCLUSIONS

Peak swelling represents a value of post-TKA swelling that is associated with strength and function. Reducing the peak level of swelling, occurring early after surgery, may improve patient functional recovery.

LEVEL OF EVIDENCE

Level II - Prospective observational study.

Effectiveness of Vascularized Lymph Node Transfer for Extremity Lymphedema Using Volumetric and Circumferential Differences

Background

Circumferential difference of lymphedematous limbs at designated anatomic distances has been the primary mode for measuring lymphedematous extremities. Computed tomography (CT) imaging produces accurate, consistent, hygienic volume measurements and a direct limb representation. This study compares these 2 main modalities and assesses their correlation.

Methods

CT and circumferential difference measurements, costs, and correlation of patient limbs that received vascularized lymph node transfer were compared.

Results

Mean circumferential difference by tape measurement pre- and postoperatively was 31.4% ± 19.1% and 17.4% ± 8.8% for upper limbs and 43.2% ± 16.1% and 22.4% ± 12% for the lower limbs, respectively. Mean CT volumetric difference pre- and postoperatively were 36.1 ± 4.1% and 27.2 ± 2.8% for the upper limb and 46.2 ± 3.2% and 33.2 ± 2.1% for the lower limbs, respectively. CT volume measurements significantly correlated with their respective circumferential difference with Pearson correlation coefficient of r = +0.7, which was statistically significant (P = 0.03), indicating a strong positive correlation between circumferential difference and actual limb volume changes as determined by CT imaging. Circumferential differences are more cost effective than CT volume assessments in the domains of measurement frequency (P = 0.03), fee (P < 0.01), time (P = 0.03), total cost per year (P < 0.01), and cost/minute (P = 0.03).

Conclusions

Standardized circumferential differences that are currently used are comparable to unbiased CT volumetric measurements and can be used as a reliable, reproducible, minimally invasive, low cost, and accurate method of measuring the lymphedematous limbs.

Self-Measured Arm Circumference in Women With Breast Cancer Is Reliable and Valid

BACKGROUND

Prospective surveillance by physical therapists enables early detection and treatment of breast cancer-related lymphedema (BCRL). Strategies to increase access to prospective surveillance could reduce the burden of BCRL on patients and the health system. One potential solution is self-managed surveillance that does not require in-person assessment by a specialized physical therapist.

OBJECTIVE

The objective was to develop and test the reliability and validity of a written and video-supported protocol for women with breast cancer to self-measure arm circumference.

DESIGN

This was a cross-sectional reliability and validity study.

RESULTS

The intrarater reliability between CIRself_home and CIRself_lab and the interrater reliability between CIRself_lab and CIRther was high to excellent for both arms in both groups (intraclass correlation coefficient ≥0.86). VOLself_lab correlated strongly with VOLper (r ≥ 0.95), demonstrating excellent validity. Participants reported strong intention, self-efficacy, and positive attitude toward the performance of self-managed surveillance for BCRL, which was not perceived to increase worry about having or getting BCRL.

METHODS

Participants with (n = 20) and without (n = 21) BCRL completed self-measurement of arm circumference on both arms at home (CIRself_home) and at the lab (CIRself_lab) (intrarater reliability). The CIRself_lab was subsequently compared to measures performed by a specialized physical therapist (CIRther) (interrater reliability). To test validity, arm volume calculated from the self-measurements (VOLself_lab) was compared to perometry measurements (VOLper). Participants completed a questionnaire to assess attitudes for performing self-managed surveillance for BCRL.

LIMITATIONS

These findings need to be replicated in a clinical setting to confirm the reliability and acceptability of self-managed surveillance for BCRL among women newly diagnosed with breast cancer.

CONCLUSIONS

Self-measured arm circumference is reliable and valid among women with and without BCRL. Self-managed surveillance for BCRL can support self-efficacy without increasing anxiety.

Breast Cancer Systemic Treatments and Upper Limb Lymphedema: A Risk-Assessment Platform Encompassing Tumor-Specific Pathological Features Reveals the Potential Role of Trastuzumab

Breast cancer related lymphedema (BCRL) is frequent but strategies for an individualized risk assessment are lacking. We aimed to define whether tumor-specific pathological features, coupled with clinical and therapeutic data, could help identify patients at risk. Data from 368 patients with node-positive breast cancers were retrospectively collected, including 75 patients with BCRL (0.4⁻25.6 years follow-up). BCRL was assessed during the standard follow-up oncology visits using the circumferential measurement. Clinicopathologic and therapeutic factors associated with BCRL were integrated into a Cox proportional hazards regression model. Lymphovascular invasion (LVI) was more common in BCRL patients (n = 33, 44% vs. n = 85, 29%, p = 0.01), akin extra nodal extension (ENE) of the metastasis (n = 57, 76% vs. n = 180, 61%, p = 0.02). Sentinel lymph node excision without axillary dissection and extra-axillary radiotherapy were BCRL-unrelated. A higher number of BCRL-positive patients were treated with taxane-based chemotherapy with or without trastuzumab, compared to BCRL-negative patients (p < 0.01). Treatment with trastuzumab and/or taxanes, adjusted for systemic infections, laterality, therapy, and pathological features (i.e., LVI and ENE), had a significant impact in BCRL-free survival (p < 0.01). This work offers new insights on BCRL risk stratification, where the integration of clinical, therapeutic, and tumor-specific pathological data suggests a possible role of anti-human epidermal growth factor receptor 2 (HER2) therapy in BCRL pathogenesis.

Development of a reference chart to monitor postoperative swelling following total knee arthroplasty

Title: Development of a reference chart to monitor postoperative swelling following total knee arthroplasty.Purpose: Lower extremity swelling is a feature of total knee arthroplasty. Until recently, clinicians lacked tools to accurately measure swelling in clinical settings, but bioelectrical impedance assessment has shown promise in this regard. The purpose of this study was to develop a reference chart of lower extremity swelling following total knee arthroplasty.Method: Fifty-six participants (54% male, mean age = 64 years) were followed for the first 7 weeks following total knee arthroplasty, during which frequent lower extremity bioelectrical impedance assessments were performed. Using Generalized Additive Models for Location Scale and Shape, a reference chart for swelling was developed with bioelectrical impedance assessment data from the first 40 patients enrolled in the study (223 observations) and preliminarily tested for performance in the remaining 16 patients' data (96 observations).Results: The reference chart illustrates approximately 10% per day increase for the first 3 days following surgery. Peak swelling occurs 6-8 days following surgery; the 10th percentile demonstrates a peak of 25%, whereas the 90th percentile peaks at 47%. In the test data, this reference chart demonstrated accurate coverage at each estimated centile.Conclusion: The reference chart provides a novel framework for monitoring swelling following total knee arthroplasty and may augment clinical decisions to improve postoperative swelling management.Implications for rehabilitationThe use of bioelectrical impedance assessment provides an accurate and easily implemented approach for rehabilitation professionals to measure swelling.The reference chart provided allows for monitoring of patient recovery of swelling following total knee arthroplasty.Precise depictions of where a patient's swelling is in reference to others will improve clinical decision making at the individual level.

Tackling the diversity of breast cancer related lymphedema: Perspectives on diagnosis, risk assessment, and clinical management

Breast cancer related lymphedema (BCRL) develops as a consequence of surgical treatment and/or radiation therapy in a significant number of breast cancer patients. The etiology of this condition is multifactorial and has not yet been completely elucidated. Risk factors include high body mass index, radical surgical procedures (i.e. mastectomy and axillary lymph node dissection), number of lymph nodes removed and number of metastatic lymph nodes, as well as nodal radiation, and chemotherapy. However, these predisposing factors explain only partially the BCRL occurrence, suggesting the possible involvement of individual determinants. Despite the implementation of conservative approaches, BCRL still remains in a proportion of cases an incurable and progressive condition with major physical and psychological implications. To date, diagnostic methods and staging systems lack uniformity, leading to a possible underestimation of the real incidence of this condition, decreasing early detection and thus the possibility of an effective treatment. Several preventive and therapeutic options are available, both conservative and surgical, but are not included in a standardized intervention protocol, tailored on patient's specific characteristics. In this review, we provide a comprehensive overview of the current state-of-knowledge of BCRL management, novel advantages in the assessment of pre-operative evaluation and risk prediction and discuss strengths and weaknesses of diagnostic and treatment strategies currently accessible in clinical practice.

Comprehensive Validation Study of Quality-of-Life Questionnaire Using Objective Clinical Measures: Breast Cancer Treatment Outcome Scale (BCTOS), Brazilian Portuguese Version

INTRODUCTION

When evaluating a quality-of-life questionnaire (QLQ), many validation studies do not correlate quality-of-life scores with objective measurements of complications associated with treatment.

PATIENTS AND METHODS

We performed a cross-sectional observational study with 300 patients submitted to breast-conserving therapy. The patients answered the European Organization for Research and Treatment of Cancer (EORTC) QLQs C-30 and BR23, as well as the Brazilian Portuguese version of the Breast Cancer Treatment Outcome Scale (BCTOS) questionnaire. Retest, internal consistency, factorial analysis, convergent/divergent analysis, and Rasch evaluation were performed. All patients underwent physical evaluations to assess lymphedema, handgrip strength, shoulder range of motion, breast cosmesis, and breast pain, and these groups were compared on the basis of BCTOS scores. Receiver operating characteristic curve determined the predictive value of BCTOS scores associated with clinical practice.

RESULTS

The internal consistencies of the BCTOS domains ranged from 0.785 to 0.895. Factor analysis grouped according to the original questionnaire. Convergent validation showed differences in the sexual functioning and sexual enjoyment domains of the EORTC BR23. Analysis of known groups found that in most domains, the scores were higher in patients with lymphedema, strength deficit, shoulder range-of-motion alteration, poor breast cosmesis, breast pain, and axillary lymphadenectomy. Using a cutoff of 1.26, lymphedema was associated with the edema domain; using a cutoff of 1.33, Late Effects Normal Tissue Task Force/Subjective, Objective, Management, Analytic pain was associated with the pain domain; and using a cutoff of 2.37, the cosmetic domain was associated with subjective cosmesis.

CONCLUSION

The association of objective measurements in a validation study of quality of life qualified the study and allowed us to develop better parameters for comparisons of results of breast-conserving therapy between populations.

Intra- and Interrater Reliability and Concurrent Validity of a New Tool for Assessment of Breast Cancer-Related Lymphedema of the Upper Extremity

OBJECTIVE

The goal of this study was to develop and assess intra- and interrater reliability and validity of a clinical evaluation tool for breast cancer-related lymphedema, for use in the context of outcome evaluation in clinical trials.

DESIGN

Blinded repeated measures observational study.

SETTING

Outpatient research laboratory.

PARTICIPANTS

Breast cancer survivors with and without lymphedema (N=71).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

The assessment of intraclass correlation coefficients (ICCs) for the Breast Cancer-Related Lymphedema of the Upper Extremity (CLUE) standardized clinical evaluation tool.

RESULTS

Intrarater reliability for the CLUE tool was ICC: 0.88 (95% confidence interval [95% CI], 0.71-0.96). Interrater reliability for the CLUE tool was ICC: 0.90 (95% CI, 0.79-0.95). Concurrent validity of the CLUE score (Pearson r) was 0.79 with perometric interlimb difference and 0.53 with the Norman lymphedema overall score.

CONCLUSIONS

The CLUE tool shows excellent inter- and intrarater reliability. The overall CLUE score for the upper extremity also shows moderately strong concurrent validity with objective and subjective measures. This newly developed clinical, physical assessment of upper extremity lymphedema provides standardization and a single score that accounts for multiple constructs. Next steps include evaluation of sensitivity to change, which would establish usefulness to evaluate intervention efficacy.

Lymphovascular invasion and extranodal tumour extension are risk indicators of breast cancer related lymphoedema: an observational retrospective study with long-term follow-up

Background

Breast cancer related lymphoedema (BCRL) occurs in a substantial proportion of breast cancer survivors and is a major contributor to patients’ disability. Regrettably, there are no validated predictive biomarkers, diagnostic tools, and strong evidence-supported therapeutic strategies for BCRL. Here, we provide an integrative characterization of a large series of women with node-positive breast cancers and identify new bona fide predictors of BCRL occurrence.

Methods

Three hundred thirty-two cases of surgically-treated node-positive breast cancers were retrospectively collected (2–10.2 years of follow-up). Among them, 62 patients developed BCRL. To identify demographic and clinicopathologic features related to BCRL, Fisher’s exact test or Chi-squared test were carried out for categorical variables; the Wilcoxon rank-sum was employed for continuous variables. Factors associated with BCRL occurrence were assessed using a Cox proportional hazards regression model.

Results

En-bloc dissection of the axillary lymph nodes but not the type of breast surgery impacted on BCRL development. Most of BCRL patients had a Luminal A-like neoplasm. The median number of lymph nodes involved by metastatic deposits was significantly higher in BCRL compared to the control group (p = 0.04). Both peritumoral lymphovascular invasion (LVI) and extranodal extension (ENE) of the metastasis had a negative impact on BCRL-free survival (p = 0.01). Specifically, patients with LVI and left side localization harboured 4-fold higher risk of developing BCRL, while right axillary nodes metastases with ENE increased the probability of BCRL compared to ENE-negative patients.

Conclusions

Assessment of LVI and ENE should be integrated with clinical and surgical data to improve BCRL risk stratification.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4851-2) contains supplementary material, which is available to authorized users.

Bioelectrical impedance analysis; a new method to evaluate lymphoedema, fluid status, and tissue damage after gynaecological surgery - A systematic review

The aim of this descriptive review is to summarise the current knowledge of non-invasive bioelectrical impedance analysis (BIA) used with gynaecological surgical patients in regard to postoperative development of lymphoedema and determination of perioperative fluid balance, and as a prognostic factor in cancer mortality and a predictor of postoperative complications. The databases PubMed, MEDLINE, Scopus Web of Science, the Cochrane Library, and reference lists of selected articles were searched for relevant articles published during the period January 2008-April 2018. Only papers published in English were retrieved. Thirty-seven articles were evaluated. Where gynaecological studies were lacking, studies with a study population from neighbouring clinical fields were used instead. Studies on the clinical use of BIA with gynaecological surgical patients were divided into three categories: the postoperative development of lower limb lymphoedema (n = 7), perioperative hydration measuring (n = 3), and the BIA parameter phase angle as a prognostic factor in cancer survival and as predictive for postoperative complications (n = 6). Of these 16 studies only three used a pure gynaecological study population. Three different methods of BIA were used in these articles: single frequency-BIA, multifrequency-BIA and bioimpedance spectroscopy. BIA was found to detect lymphoedema with a sensitivity of 73% and a specificity of 84%. Studies indicated that BIA was able to detect lower limb lymphoedema at an early stage even before it became clinically detectable. During postoperative hydration measurements, an increase in extracellular fluid volume and extracellular fluid volume in relation to total body fluid volume, as well as a decrease in phase angle, were associated with higher frequencies of postoperative complications. Moreover, low values for the phase angle have been associated with increased mortality in cancer patients. However, the number of studies in this field was limited. From our review, BIA seems to be a useful tool for use in the clinical setting of the gynaecological surgical patient. The theoretical approach of using bioelectrical impedance values to measure the fluid distribution in the body compartments offers wide opportunities in the clinical setting. However, so far, all studies have set up cut-off limits within the study population, and reference values for a general population need to be defined. There are also rather few studies on a gynaecological study population. Hence, there is a need for further studies within gynaecological surgery focusing on early detection of lower limb lymphoedema, perioperative fluid balance, and postoperative complications in order to establish the value of BIA in clinical praxis.

Protocol of a randomised controlled trial regarding the effectiveness of fluoroscopy-guided manual lymph drainage for the treatment of breast cancer-related lymphoedema (EFforT-BCRL trial)

OBJECTIVES

Lymphoedema is a dreadful complication following breast cancer therapy. According to the International Society of Lymphology, the consensus treatment for breast cancer-related lymphoedema (BCRL) is the decongestive lymphatic therapy. This is a two-phase treatment and combines different treatment modalities including skin care, manual lymphatic drainage (MLD), compression therapy and exercise. However, the additional effect of MLD is debated since pooled data only demonstrated a limited non-significant additional value. A possible explanation is that in previous studies MLD has been applied blind, without knowledge of patient-specific lymphatic routes of transport. In addition, the MLD hand manoeuvres used by the therapists in previous studies, possibly did not optimally stimulate lymphatic transport. Recently, near-infrared fluorescence imaging has been introduced to visualise the superficial lymphatic network which allows MLD at the most needed location. The aim of the present study is to determine the effectiveness of the fluoroscopy-guided MLD, additional to the other parts of the decongestive lymphatic therapy and compared to the traditional or a placebo MLD, in the treatment of BCRL.

STUDY DESIGN

A three-arm double-blinded randomised controlled trial will be conducted in different university hospitals in Belgium. Based on a sample size calculation, 201 participants with chronic BCRL stage 1 or 2 of the arm or hand, with at least 5% difference between both sides (corrected for hand dominance) need to be recruited. All participants receive the standard treatment: skin care, compression therapy and exercises. The intervention group additionally receives fluoroscopy-guided MLD. One control group additionally receives the traditional 'blind' MLD and a second control group receives a placebo MLD. All subjects receive 3 weeks of daily intensive treatments and 6 months of maintenance treatment. Follow-up period is 6 months. The primary outcomes are the reduction in lymphoedema volume of the arm/hand and the change in stagnation of lymph fluid at level of the shoulder/trunk.

Changes in volume and incidence of lymphedema during and after treatment with docetaxel, doxorubicin, and cyclophosphamide (TAC) in patients with breast cancer

Purposes

The purposes of this study were to investigate the incidence of lymphedema in patients with breast cancer during and after adjuvant treatment with docetaxel, doxorubicin, and cyclophosphamide (TAC), to identify predictors for development of lymphedema, and to describe consequences in daily life in relation to lymphedema.

Methods

This is a prospective study with measurements before chemotherapy (T0), during chemotherapy before cycle 2 (T1), cycle 4 (T2), and 1 month after completion of treatment (T3). Volume change was monitored using tape measurements. Lymphedema was defined as ≥ 10% volume difference. Linear mixed-effect models were estimated to analyze differences in arm volume and consequences in daily life (total score and domain scores of the Lymph-International Classification of Functioning (ICF) questionnaire) over time and to identify treatment and patient characteristics as predictors for changes in volume.

Results

Forty-eight patients completed all measurements. Volume did not change during TAC treatment. One month after treatment, volume was significantly increased compared to T0-T2, and 12 patients (25%) had developed lymphedema. Axillary lymph node dissection was associated with lymphedema (ES 2.9, 95% CI 0.02–5.7; p < 0.05). In patients with and without lymphedema, 1 month after completion (T3), the Lymph-ICF questionnaire showed significant limitations in physical function compared to T0-T2. In patients with lymphedema at T3, a significant association between volume and total score on the Lymph-ICF questionnaire on physical function and mobility activities was observed.

Conclusions

One month after treatment in 12 patients (25%), volume difference increased over 10%. Axillary lymph node dissection was predictive for development of lymphedema. All patients, but more patients with lymphedema, perceived difficulties in activities in daily life after treatment.

Investigation of Shape with Patients Suffering from Unilateral Lymphoedema

This study investigates the use of a 3D depth sensing camera for analysing the shape of lymphoedematous arms, and seeks to identify suitable metrics for monitoring lymphoedema clinically. A fast, simple protocol was developed for scanning upper limb lymphoedema, after which a robust data pre- and post-processing framework was built that consistently and quickly identifies arm shape and volume. The framework was then tested on 24 patients with mild unilateral lymphoedema, who were also assessed using tape measurements. The scanning protocol developed led to scanning times of about 20–30 s. Shape related metrics such as circumference and circularity were used to distinguish between affected and healthy arms (p ≤ 0.05). Swelling maps were also derived to identify the distribution of oedema on arms. Topology and shape could be used to monitor or even diagnose lymphoedema using the provided framework. Such metrics provide more detailed information to a lymphoedema specialist than solely volume. Although tested on a small cohort, these results show promise for further research into better diagnostics of lymphoedema and for future adoption of the proposed methods across lymphoedema clinics.

Diagnosis of Upper Quadrant Lymphedema Secondary to Cancer: Clinical Practice Guideline From the Oncology Section of the American Physical Therapy Association

The Oncology Section of the American Physical Therapy Association (APTA) developed a clinical practice guideline to aid the clinician in diagnosing secondary upper quadrant cancer-related lymphedema. Following a systematic review of published studies and a structured appraisal process, recommendations were written to guide the physical therapist and other health care clinicians in the diagnostic process. Overall clinical practice recommendations were formulated based on the evidence for each diagnostic method and were assigned a grade based on the strength of the evidence for different patient presentations and clinical utility. In an effort to maximize clinical applicability, recommendations were based on the characteristics as to the location and stage of a patient's upper quadrant lymphedema.

Diagnosis of Upper-Quadrant Lymphedema Secondary to Cancer: Clinical Practice Guideline From the Oncology Section of APTA

INTRODUCTION

The Oncology Section of APTA developed a clinical practice guideline to aid the clinician in diagnosing secondary upper-quadrant cancer-related lymphedema.

METHODS

Following a systematic review of published studies and a structured appraisal process, recommendations were written to guide the physical therapist and other health care clinicians in their diagnostic process. Overall, clinical practice recommendations were formulated on the basis of the evidence for each diagnostic method and were assigned a grade based on the strength of the evidence for different patient presentations and clinical utility.

RECOMMENDATIONS

In an effort to make these clinically applicable, recommendations were based on the characteristics as to the location and stage of a patient's upper-quadrant lymphedema.

Microsurgery guided by sequential preoperative lymphography using 68Ga-NEB PET and MRI in patients with lower-limb lymphedema

OBJECTIVE

The popularity of contemporary microsurgical techniques in treatment of lower-limb lymphedema calls for better visualization of the lymphatic system, both preoperatively and intra-operatively. The aim of this prospective study was to investigate the feasibility of a novel combination of ⁶⁸Ga-NEB positron emission tomography (PET) with magnetic resonance lymphography (MRL) in evaluating lymphedema and guiding surgical intervention.

METHODS

A total of 11 patients (F 9, M 2, age range 29-69 y) with lower-limb lymphedema classified into stage I to III were recruited. PET acquisition was performed at 30, 60 and 90 min after subcutaneous injection of the albumin-binding radiotracer ⁶⁸Ga-NEB into the bilateral first web spaces of the feet. All the patients were also subjected to ^99mTc-sulfur colloid (SC) lymphoscintigraphy for comparison. Gd-DTPA-enhanced magnetic resonance imaging (MRI) was performed using sequences specialized for lymphatic vessel scans. All the patients underwent surgical interventions within a week. The surgical approach includes the use of a linear marker for edema localization and indocyanine green (ICG) lymphography with a near-infrared surgical navigation system intra-operatively.

RESULTS

Lymph transport in lymphatic channels was clearly observed by visualization of ⁶⁸Ga-NEB activity in the lymphatic vessels and within lymph nodes for all 11 patients as well as the visualization of the edema section plane with dermal backflow (DB), abnormally increased and disconnected uptake along the lymphatic channels. Preoperative ⁶⁸Ga-NEB PET combined with MRL provides advantageous three-dimensional images, higher temporal resolution, significantly shorter time lapse before image acquisition after tracer injection and more accurate pathological lymphatic vessel distribution than ^99mTc-SC lymphoscintigraphy combined with MRI.

CONCLUSION

This study documented an effective imaging pattern to combine ⁶⁸Ga-NEB PET and MRL in patients with lower-limb lymphedema. This strategy demonstrated significant advantage over ^99mTc-SC lymphoscintigraphy/MRL in the evaluation of lymphedema severity, staging and pathological location of lymph vessels to make an individualized treatment plan. Dual ⁶⁸Ga-NEB PET/MRL is thus recommended before the operation for staging and therapy planning.