Reliability of a radiological grading system for dermal backflow in lymphoscintigraphy imaging

Efficacy of preoperative lymphoscintigraphy in predicting surgical outcomes of lymphaticovenous anastomosis in lower extremity lymphedema: Clinical correlations in gynecological cancer-related lymphedema

BACKGROUND

Lymphaticovenous anastomosis (LVA) is a promising microsurgical treatment for lower extremity lymphedema (LEL). Lymphoscintigraphy effectively assesses lower limb lymphatic systems before LVA, but its role in predicting the therapeutic outcomes of LVA is indeterminate. In this study we investigate the efficacy of preoperative lymphoscintigraphy using clinical findings to predict outcomes in gynecological cancer-related LEL patients who underwent LVA.

METHODS

A retrospective review was conducted on consecutive gynecological cancer patients with LEL who had undergone LVA between June 2018 and June 2021. The therapeutic efficacy was assessed by measuring the change rate of the lower extremity lymphedema index (LELi) six months after surgery. Clinical data and lymphoscintigraphic findings were analyzed to assess therapeutic efficacy of LVA.

RESULTS

Out of the 60 evaluated legs, 83.3% of the legs showed improved results after LVA. Univariable linear regression analysis revealed that higher preoperative LELi, and ovarian cancer were associated with superior LELi change rate (LC rate). Absence of dermal backflow (DBF) on lymphoscintigraphy was associated with inferior LC rate. Multivariable linear regression analysis identified ovarian cancer and higher preoperative LELi were independently correlated with favorable outcomes, while the absence of DBF was independently correlated with inferior outcomes.

CONCLUSION

The results of this study emphasizes the effectiveness of preoperative lymphoscintigraphy, preoperative LELi, and primary malignancy as predictors of LVA outcomes in gynecological cancer-related LEL patients.

MRI of Lymphedema

Lymphedema is a devastating disease that has no cure. Management of lymphedema has evolved rapidly over the past two decades with the advent of surgeries that can ameliorate symptoms. MRI has played an increasingly important role in the diagnosis and evaluation of lymphedema, as it provides high spatial resolution of the distribution and severity of soft tissue edema, characterizes diseased lymphatic channels, and assesses secondary effects such as fat hypertrophy. Many different MR techniques have been developed for the evaluation of lymphedema, and the modality can be tailored to suit the needs of a lymphatic clinic. In this review article we provide an overview of lymphedema, current management options, and the current role of MRI in lymphedema diagnosis and management. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 5.

Evaluation of Longitudinal Lymphatic Function Changes upon Injury in the Mouse Tail with Photodynamic Therapy

PURPOSE

The lymphatic system is an essential but often understudied component of the circulatory system in comparison with its cardiovascular counterpart. Such disparity could often be explained by the difficulty in imaging lymphatics and the specialized microsurgical skills that are often required for lymphatic injury models. Recently, it has been shown that verteporfin, a photosensitive drug used for photodynamic therapy (PDT) to ablate the blood vessels, provides a similar effect on lymphatic vessels. Here, we seek to administer verteporfin and perform a modified form of PDT on collecting lymphatics in the mouse tail, a commonly used location for the study of lymphatic disorders, and examine lymphatic remodeling, contractility, and transport in response to the procedure.

METHODS

Mice collecting lymphatics in the tail were injured by PDT through an intradermal injection of verteporfin in the distal tip of the tail followed by light activation on the proximal portion of the tail downstream of the injection site. Lymphatic function was evaluated using a near-infrared (NIR) imaging system weekly for up to 28 days after injury.

RESULTS

PDT resulted in a loss in lymphatic function contractile frequency that persisted for up to 7 days after injury. Packet transport and packet amplitude, measurements reflective of the strength of contraction, were significantly reduced 14 days after injury. The lymphatics showed a delayed increase in lymphatic leakage at 7 days that persisted until the study endpoint on day 28.

CONCLUSION

This technique provides an easy-to-use method for injuring lymphatics to understand their remodeling response to injury by PDT as well as potentially for screening therapeutics that seek to normalize lymphatic permeability or contractile function after injury.

Three-dimensional analysis of dermal backflow in cancer-related lymphedema using photoacoustic lymphangiography

Background

Dermal backflow (DBF), which refers to lymphatic reflux due to lymphatic valve insufficiency, is a diagnostic finding in lymphedema. However, the three-dimensional structure of DBF remains unknown. Photoacoustic lymphangiography (PAL) is a new technique that enables the visualization of the distribution of light-absorbing molecules, such as hemoglobin or indocyanine green (ICG), and can provide three-dimensional images of superficial lymphatic vessels and the venous system. This study reports the use of PAL to visualize DBF structures in the extremities of patients with lymphedema after cancer surgery.

Methods

Patients with a clinical or lymphographic diagnosis of lymphedema who previously underwent surgery for cancer at one of two participating hospitals were included in this study. PAL was performed using the PAI-05 system. ICG was administered subcutaneously in the affected hand or foot, and ICG fluorescence lymphography was performed using a nearinfrared camera system prior to PAL.

Results

Between April 2018 and January 2019, 21 patients were enrolled and examined using PAL. The DBF was composed of dense, interconnecting, three-dimensional lymphatic vessels. It was classified into three patterns according to the composition of the lymphatic vessels: a linear structure of lymphatic collectors (pattern 1), a network of lymphatic capillaries and lymphatic collectors in an underlying layer (pattern 2), and lymphatic capillaries and precollectors with no lymphatic collectors (pattern 3).

Conclusions

PAL showed the structure of DBF more precisely than ICG fluorescence lymphography. The use of PAL to visualize DBF assists in understanding the pathophysiology and assessing the severity of cancer-related lymphedema.

Lymphoscintigraphy as an Outcome Measurement for Conservative Upper Limb Lymphedema Treatments: A Systematic Review

Introduction: The impact of conservative interventions on lymphatic function and the relationship to clinical outcomes is currently unknown. A systematic review was undertaken to evaluate studies that used lymphoscintigraphy to measure outcomes from conservative intervention for secondary arm lymphedema and to explore the relationship between changes in the lymphoscintigraphy and clinical outcomes. Methods and Results: Five databases were systematically searched using the selection criteria: randomized controlled trials (RCTs); quasi-RCTs; pre/post and cohort studies; upper limb secondary lymphedema; use of lymphoscintigraphy as an outcome measure; and conservative intervention. Seven articles met the inclusion criteria. Compression, exercise, hyperbaric oxygen therapy, and pharmacological interventions were evaluated using lymphoscintigraphy. There was heterogeneity with all aspects of the lymphoscintigraphy techniques, including radioisotope used, injection location, use of exercise, and imaging sequence between the studies as well as the outcome analysis. Also most studies did not show a relationship between the clinical and lymphoscintigraphy outcomes measured. Conclusions: Lymphoscintigraphy has not been used regularly or recently to evaluate conservative upper limb lymphedema treatment outcomes. Lack of standardization of lymphoscintigraphy protocols and lack of consensus and understanding of the lymphoscintigraphy analyses used to measure the outcomes of diverse conservative lymphedema interventions currently limit the use of lymphoscintigraphy as an outcome measure. Further research adopting recent guidelines to standardize lymphoscintigraphy and use of reliable analysis techniques that measure the physiological impact of the chosen conservative lymphedema intervention is recommended to evaluate the impact of conservative interventions on lymphatic function.

Lower limb lymphedema staging based on magnetic resonance lymphangiography

OBJECTIVE

Dermal backflow (DBF) and reduced lymphatic visualization are common findings of lymphedema on various imaging modalities. However, there is a lack of knowledge about how these findings vary with the anatomic location and severity of lymphedema, and previous reports using indocyanine green lymphography or lymphoscintigraphy show variable results. Magnetic resonance lymphangiography (MRL) is expected to clarify this clinical question due to its superior ability for lymphatic visualization. This retrospective study aimed to investigate the following: (1) Are there any characteristic patterns for DBF and lymphatics' visualization, depending on the anatomic location within lower limbs and severity of lymphedema? (2) Is it possible to classify the severity of lymphedema based on MRL findings?

METHODS

Two radiologists performed consensus readings of MRL of 56 patients (112 limbs) with lower-limb lymphedema. The frequency of visualized DBF and lymphatics was analyzed in six regions in each lower limb. The results were compared with the International Society of Lymphology clinical stages and etiology of lymphedema. Characteristic findings were categorized and compared with the clinical stage and duration of lymphedema.

RESULTS

DBF and lymphatics were observed more frequently in the distal regions than the proximal regions of lower limbs. DBF appeared more frequently as the clinical stage increased, reaching statistical significance (P < 10^-3) between stages 0 or I and II. DBF above the knee joint was rarely observed (0.48%) in early stages (0 and I) but appeared more frequently (13.5%, P < 10^-5) in stage II. Lymphatics appeared less frequently as the stage progressed, with significant differences (P < .05) between stages I and II and between II and III. The frequency of lymphatics above the knee joint decreased significantly (P < .05) between stages I and II and between II and III as the stage progressed, reaching 0% in stage III. An MRL staging was proposed and showed significant positive correlations with the clinical stage (r = 0.79, P < .01) and the duration of lymphedema (r = 0.57, P < .01).

CONCLUSIONS

MRL-specific patterns of DBF and lymphatics that depended on the site within the lower limb and clinical stage were shown. The DBF pattern differed from those observed in previous studies with other imaging techniques. The proposed MRL staging based on these characteristic findings allows new stratification of patients with lymphedema. Combined with its excellent ability to visualize lymphatic anatomy, MRL could enable a more detailed understanding of individual patient's pathology, useful for determining the most appropriate treatment.

Lymphoscintigraphic Findings as Indicators of Lymphaticovenous Anastomosis Outcome in Patients With Extremity Lymphedema: A Retrospective Cohort Study

PURPOSE

This study was performed to evaluate the usefulness of lymphoscintigraphy in predicting the surgical outcomes of lymphaticovenous anastomosis (LVA) in a patient with extremity lymphedema.

PATIENTS AND METHODS

We retrospectively evaluated 133 patients with extremity lymphedema who underwent lymphoscintigraphy followed by LVA surgery from February 2018 to March 2020. Lymphoscintigraphic findings were evaluated on the following parameters: the extent of dermal backflow (small/large), lymphatic flow patterns (trunk flow pattern/proximal-restricted pattern/distal-restricted pattern), visualization of lymph nodes, and collateral lymphatic vessels. The mean circumferential difference change before and after surgery, circumferential reduction (CR) rate (%), was used as the clinical outcome variables.

RESULTS

A decrease in circumference was observed in 93 (69.9%) of 133 patients after LVA. The extent of dermal backflow and lymphatic flow patterns was significantly correlated with improved clinical outcomes after LVA. The large extent of the dermal backflow group showed a more significant CR rate than the small extent (19.27% vs 1.24%, P = 0.005). The TP group showed the most significantly decreased CR rate to 21.46%, and the proximal-restricted pattern and distal-restricted pattern groups were -2.49% and -5.33%, respectively (P < 0.001). Multivariate analysis revealed that dermal backflow and lymphatic flow patterns were independent predictors of therapeutic outcome (P < 0.001).

CONCLUSIONS

Our study demonstrates that pretreatment lymphoscintigraphy may help predict the therapeutic effect of LVA in patients with extremity lymphedema. Furthermore, dermal backflow and lymphatic flow patterns are independent predictors of CR rate after LVA surgery for extremity lymphedema.

MRI staging of upper extremity secondary lymphedema: correlation with clinical measurements

OBJECTIVES

Staging of upper extremity lymphedema is needed to guide surgical management, but is not standardized due to lack of accessible, quantitative, or precise measures. Here, we established an MRI-based staging system for lymphedema and validate it against existing clinical measures.

METHODS

Bilateral upper extremity MRI and lymphoscintigraphy were performed on 45 patients with unilateral secondary lymphedema, due to surgical intervention, who were referred to our multidisciplinary lymphedema clinic between March 2017 and October 2018. MRI short-tau inversion recovery (STIR) images were retrospectively reviewed. A grading system was established based on the cross-sectional circumferential extent of subcutaneous fluid infiltration at three locations, labeled MRI stage 0-3, and was compared to L-Dex®, ICG lymphography, volume, lymphedema quality of life (LYMQOL), International Society of Lymphology (ISL) stage, and lymphoscintigraphy. Linear weighted Cohen's kappa was calculated to compare MRI staging by two readers.

RESULTS

STIR images on MRI revealed a predictable pattern of fluid infiltration centered on the elbow and extending along the posterior aspect of the upper arm and the ulnar side of the forearm. Patients with higher MRI stage were more likely to be in ISL stage 2 (p = 0.002) or to demonstrate dermal backflow on lymphoscintigraphy (p = 0.0002). No correlation was found between MRI stages and LYMQOL. Higher MRI stage correlated with abnormal ICG lymphography pattern (r_s = 0.63, p < 0.0001), larger % difference in limb volume (r_s = 0.68, p < 0.0001), and higher L-Dex® ratio (r_s = 0.84, p < 0.0001). Cohen's kappa was 0.92 (95% CI, 0.85-1.00).

CONCLUSION

An MRI staging system for upper extremity lymphedema offers an improved non-invasive precision marker for lymphedema for therapeutic planning.

KEY POINTS

• Diagnosis and staging of patients with secondary upper extremity lymphedema may be performed with non-contrast MRI, which is non-invasive and more readily accessible compared to lymphoscintigraphy and evaluation by lymphedema specialists. • MRI-based staging of secondary upper extremity lymphedema is highly reproducible and could be used for long-term follow-up of patients. • In patients with borderline clinical measurements, MRI can be used to identify patients with early-stage lymphedema.

A Case-Control Study of the Lymphatic Phenotype of Yellow Nail Syndrome

BACKGROUND

Yellow nail syndrome (YNS) is a rare disease manifesting as a triad of yellow-green dystrophic nails, lymphedema, and chronic respiratory disease. The etiology of YNS is obscure and investigations are few. A single lymphatic pathogenesis has been proposed to account for all the associated features, and despite the lack of evidence for a unifying lymphatic mechanism, this hypothesis prevails. The objective was to explore the lymphatic phenotype in YNS and to establish whether lymphatic dysfunction could be a major contributing factor to the disease process.

METHODS AND RESULTS

Four-limb lymphoscintigraphy was performed on patients with YNS and on healthy, age-matched controls. All 17 patients had lower limb swelling, and 14 (82%) had upper limb swelling also, including 5 (29%) with hand involvement. None of the YNS lymph scans was completely normal. Combined qualitative and quantitative assessment showed that 67% of YNS scans were clearly abnormal compared with 36% of healthy control scans. Mean axillary and ilio-inguinal nodal tracer uptakes were 41%-44% lower in the YNS group than in the controls (p < 0.0001).

CONCLUSIONS

YNS is a lymphatic phenotype because lymphatic insufficiency was found to exist in all patients and the insufficiency was widespread (upper and lower limbs), with a common mechanistic fault of poor transport. The origin of the lymphatic fault is unclear. In healthy individuals, lymphatic abnormalities may be relatively common in the fifth decade of life onward.

Procedural Recommendations for Lymphoscintigraphy in the Diagnosis of Peripheral Lymphedema: the Genoa Protocol

INTRODUCTION

Lymphoscintigraphy is the gold standard for imaging in the diagnosis of peripheral lymphedema. However, there are no clear guidelines to standardize usage across centers, and as such, large variability exists. The aim of this perspectives paper is to draw upon the knowledge and extensive experience of lymphoscintigraphy here in Genoa, Italy, from our center of excellence in the assessment and treatment of lymphatic disorders for over 30 years to provide general guidelines for nuclear medicine specialists.

METHOD

The authors describe the technical characteristics of lymphoscintigraphy in patients with limb swelling. Radioactive tracers, dosage, administration sites, and the rationale for a two-compartment protocol with the inclusion of subfascial lymphatic vessels are all given in detail.

RESULTS

Examples of lymphoscintigraphic investigations with various subgroups of patients are discussed. The concept of a transport index (TI) for semi-quantitative analysis of normal/pathological lymphatic flow is introduced. Different concepts of injection techniques are outlined.

DISCUSSION

It is past time that lymphoscintigraphy in the diagnosis of lymphatic disorders becomes standardized. This represents our first attempt to outline a clear protocol and delineate the relevant points for lymphoscintigraphy in this patient population.

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.

Diagnosis of upper limb lymphedema: development of an evidence-based approach

BACKGROUND

The diagnosis of secondary upper limb lymphedema (LE) is complicated by the lack of an agreed-upon measurement tool and diagnostic threshold. The aim of this study was to determine which of the many commonly used and normatively determined clinical diagnostic thresholds has the best diagnostic accuracy of secondary upper limb LE, when compared to diagnosis by an appropriate reference standard, lymphoscintigraphy.

MATERIAL AND METHODS

The arms of women treated for breast cancer with and without a previous diagnosis of LE, as well as healthy controls, were assessed using lymphoscintigraphy, bioimpedance spectroscopy (BIS) and perometry. Dermal backflow score determined from lymphoscintigraphy imaging assessment (reference standard) was compared with diagnosis by both commonly used and normatively determined diagnostic thresholds for volume and circumference measurements as well as BIS.

RESULTS

For those with established dermal backflow, all commonly used and normatively determined diagnostic thresholds accurately identified presence of LE compared with lymphoscintigraphy diagnosis. In participants with mild to moderate changes in dermal backflow, only a normatively determined diagnostic threshold, set at two standard deviations above the norm, for arm circumference and full arm BIS were found to have both high sensitivity (81% and 76%, respectively) and specificity (96% and 93%, respectively). For this group, strong, and clinically useful, positive (23 and 10, respectively) and negative likelihood (0.2 and 0.3) ratios were found for both the circumference and bioimpedance diagnostic thresholds.

CONCLUSION

For the first time, evidence-based clinical diagnostic thresholds have been established for secondary LE. With mild LE, normatively determined circumference and BIS thresholds are superior to the commonly used thresholds.

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.