Re-evaluation of qualitative lymphangioscintigraphic findings in secondary lower extremity lymphedema

A new indocyanine green fluorescence lymphography protocol for diagnostic assessment of lower limb lymphoedema

INTRODUCTION

The lower limbs are a common body site affected by chronic edema. Imaging examination of the lymphatic system is useful to diagnose lymphoedema, identify structural changes in individuals, and guide interventional strategies. In this study, we used a protocol combining indocyanine green (ICG) lymphography and ICG-guided manual lymphatic drainage (MLD) for the diagnostic assessment of lower limb lymphoedema.

MATERIALS AND METHODS

Patients with lower limb lymphoedema were divided into three groups by their medical history: primary, secondary cancer-related, or secondary non-cancer-related. ICG lymphography was conducted in three phases: initial observation, MLD to accelerate ICG dye transit and reduce imaging time, and imaging data collection. Lymphatic drainage regions were recorded, and the MD Anderson Cancer Center ICG staging was applied. We collected routine lymphoedema assessment data, including limb volume and bioimpedance spectroscopy measurements.

RESULTS

Three hundred and twenty-six lower limbs that underwent ICG lymphography were analyzed. Eight drainage regions were identified. The ipsilateral inguinal and popliteal were recognized as the original regions, and the remaining six regions were considered compensatory regions that occur only in lymphoedema. More than half of the secondary cancer-related lower limb lymphoedema (57.6%) continued to drain to the ipsilateral inguinal region. The incidence of drainage to the ipsilateral inguinal region was even higher for the primary (82.8%) and secondary non-cancer-related (87.1%) groups. Significant associations were observed between cancer-related lymphoedema and the presence of compensatory drainage regions.

CONCLUSIONS

We proposed a prospective ICG lymphography protocol for the diagnostic assessment of lower limb lymphoedema in combination with MLD. Eight drainage regions were identified, including two original and six compensatory regions.

Differentiation of functional venous insufficiency and leg lymphedema complicated by functional venous insufficiency using subcutaneous tissue ultrasonography

OBJECTIVE

To use subcutaneous ultrasonography to differentiate legs with edema because of obesity-related functional venous insufficiency (FVI_ob), immobility-related FVI (FVI_im), secondary lymphedema (LE), LE complicated by obesity (LE_ob), and LE complicated by immobility (LE_im).

METHODS

Ninety-nine legs with edema (16 FVI_ob, 32 FVI_im, 22 LE, 9 LE_ob, and 20 LE_im), and 10 normal legs were examined. Subcutaneous tissue ultrasonography was performed at eight points (medial, lateral, upper, lower, thigh, and calf) in each leg. Subcutaneous echogenicity (SEG) and subcutaneous echo-free space (SEFS) were assessed, and each graded as 0, 1, and 2 according to their severity.

RESULTS

In normal legs, SEG and SEFS were graded 0 in almost all parts of the leg. SEG was diffusely increased in FVI_ob, whereas SEG was increased in accordance with gravity in FVI_im (upper medial thigh, 0.6 ± 0.5 vs lower medial calf, 1.2 ± 0.4; P < .001). In LE, SEG was increased in the medial side, particularly evident in upper thigh (upper medial thigh, 1.1 ± 0.4 vs upper lateral thigh, 0.6 ± 0.6; P < .01). SEFS was increased in accordance with gravity in all of these legs (FVI_ob: upper medial thigh, 0.2 ± 0.4 vs lower medial calf, 0.7 ± 0.8; P = .05; FVI_im: upper medial thigh, 0.1 ± 0.2 vs lower medial calf, 1.3 ± 0.7; P < .0001; LE: upper medial thigh, 0.4 ± 0.7 vs lower medial calf, 0.9 ± 0.9; P < .05). The increases of SEG and SEFS in legs with LE_ob or LE_im were diffuse and similar. As determined via stepwise logistic regression analyses, the increases in SEG in the upper medial thigh and SEFS in the lower medial thigh in LE cases, the increases in SEG in the upper lateral thigh and SEFS in the lower lateral thigh in cases with obesity-related leg edema (ie, FVI_ob and LE_ob), and the increase in SEFS in the lower lateral calf in cases with immobility-related leg edema (ie, FVI_im and LE_im) were determined to be significant factors to characterize each leg edema.

CONCLUSIONS

Differences in the extent and distribution of SEG and SEFS might help in differentiating LE from FVI_ob and FVI_im, although assessment of LE complicated by obesity vs immobility remains difficult.

Differentiation of High and Low Output Lymphatic Failure Using Qualitative Lymphangioscintigraphy

PURPOSE

To use qualitative lymphangioscintigraphy (LAS) findings to differentiate leg edema caused by high and low output lymphatic failure.

METHODS

LAS was performed in legs with secondary lymphedema (LE), i.e., low output failure (N = 79), and functional venous insufficiency (FVI), i.e., high output failure (N = 56), and normal legs (N = 26). Whole body images were obtained, 15, 60, and 180 min after technetium-99m injection. The rate and timing of visualization of lymphatic structures, washout out of tracer, and presence of dermal backflow were assessed.

RESULTS

The most significant finding for differentiating LE from other conditions was not the visualization of lymphatic structures, but the washout of the tracer from the leg trunk (LE 27%, FVI 100%, normal leg 100%, P <.0001). On the other hand, the most significant finding for differentiating FVI from other legs was the visualization of inguinal lymph nodes at 15 min (LE 11%, FVI 82%, normal leg 8%, P <.0001).

CONCLUSIONS

We found that the lack of washout from the leg trunk was most suggestive of a low output status of the lymphatic system, while earlier visualization of inguinal lymph nodes was suggestive of a high output status.

Estimating Lymphodynamic Conditions and Lymphovenous Anastomosis Efficacy Using (99m)Tc-phytate Lymphoscintigraphy with SPECT-CT in Patients with Lower-limb Lymphedema

Background:

Diagnostic and therapeutic strategies for lower-limb lymphedema have not yet been established. The purpose of this study was to estimate the lymphodynamic condition and therapeutic efficacy of lymphovenous anastomosis (LVA) in lower-limb lymphedema patients using 2-phase ^99mTc-phytate lymphoscintigraphy with single-photon emission computed tomography-computed tomography (SPECT-CT).

Methods:

In this study, consecutive patients with lower-limb lymphedema who underwent 2-phase lymphoscintigraphy using ^99mTc-phytate were enrolled between June 2013 and June 2014. SPECT-CT was also performed to clarify the relationships between functional and morphological information. In both the early and delayed images, inguinal lymph node accumulation, dermal backflow, and their sequential alternations were evaluated, and liver-to-blood ratio and inguinal lymph node-to-blood ratio were calculated. All participants were classified into 6 types of lymphodynamic conditions based on the image findings. Patients with both dermal backflow and associated normal lymphatic vessel accumulation proceeded to LVA and underwent a second lymphoscintigraphy after the operation.

Results:

Of all 30 participants, the largest population was categorized as type 4, which had consistent inguinal lymph node accumulation defect with dermal backflow. In 12 operated cases, dermal backflow was degraded in 10 cases by LVA. Liver-to-blood ratio in both early and delayed images and inguinal lymph node-to-blood ratio in delayed image significantly increased after LVA.

Conclusions:

Lymphoscintigraphy with SPECT-CT can provide both functional and morphological information simultaneously in patients with lower-limb lymphedema. Using these procedures, a type categorization for the patients was devised, which reflects their lymphodynamic conditions. The therapeutic efficacy of LVA could also be estimated quantitatively by the derived findings.

A study of leg edema in immobile patients

BACKGROUND

Our objectives were to elucidate the pathophysiology of leg edema in immobile patients and to discuss reasonable management of this condition.

METHODS AND RESULTS

The 30 patients with leg edema had visited our clinic between April 2009 and March 2013; they suffered from severe gait disturbance, had no significant venous abnormalities detected using duplex ultrasound, and did not have any systemic diseases that could cause leg edema. Here, we review their symptoms, examinations, and treatments. Among 59 edematous legs of the 30 patients, 30 legs (51%) had symptoms that indicated advanced chronic venous insufficiency. The ankle range of motion and calf : ankle circumference ratio were abnormal in only 3 (5%) and 10 (17%) of the legs, respectively. The severity of edema and subcutaneous inflammation, which was confirmed using ultrasonography, was significantly influenced by gravity. Air plethysmography and lymphangioscintigraphy were completed in 15 and 10 patients, respectively, neither of which revealed any significant abnormalities. Reasonable success for all patients was achieved by compression therapy and physical therapy without medications.

CONCLUSIONS

It was assumed that leg edema in these immobile patients was mainly caused by venous stasis because of the immobility itself, not because of anatomical problems. The patients were successfully managed by compression and physical therapy alone.