Diagnostic imaging in lipedema: A systematic review.

BACKGROUND: Diagnosing lipedema remains a challenge due to its heterogeneous presentation, co-existing diseases, and the lack of objective diagnostic imaging. OBJECTIVE: This systematic review aims to outline the currently available diagnostic imaging methods to characterize lipedema in the legs along with their diagnostic performance. METHODS: PubMed, Embase, Google Scholar, Scopus, and Web of Science were searched. The quality assessment of diagnostic accuracy studies (QUADAS) tool was used for quality assessment. RESULTS: Thirty-two studies describing a total of 1154 patients with lipedema were included for final analysis. Features for lipedema have been defined using ultrasound (increased subcutaneous adipose tissue), lymphoscintigraphy (slowing of the lymphatic flow and a frequent asymmetry between the lower extremities), computed tomography (symmetrical bilateral soft tissue enlargement without either skin thickening or subcutaneous edema), magnetic resonance imaging (increased subcutaneous adipose tissue), MR lymphangiography (enlarged lymphatic vessels up to a diameter of 2 mm), and dual-energy X-ray absorptiometry (fat mass in the legs adjusted for body mass index (BMI) ≥ 0.46 or fat mass in the legs adjusted for total fat mass ≥ 0.384). CONCLUSION: The diagnostic performance of currently available imaging modalities for assessing lipedema is limited. Prospective studies are needed to evaluate and compare the diagnostic performance of each imaging modality. Imaging techniques focusing on the pathogenesis of the disease are needed.

The value of sonographic microvascular imaging in the diagnosis of lipedema.

BACKGROUND: Lipedema is a chronic disease marked by symmetric enlargement of painful nodular and fibrotic adipose tissue, predominantly affecting the limbs. Since there is no specific test or biomarker for this condition, years often pass before the diagnosis of lipedema is established for the first time, thereby causing psychosocial distress, including depression, eating disorders, and social isolation. Over the last few years several advanced Doppler-based technologies have been developed to visualize slow flow blood vessels and superficial microvascular architecture undetectable by traditional color Doppler flow imaging (CDFI). OBJECTIVE: The aim of this study was to evaluate the superficial microvascular anatomy in lipedema patients compared to healthy controls and investigate the clinical significance of the Ultra Micro Angiography (UMA) technology in the diagnosis of lipedema. This new technique may contribute to reduce the diagnostic delay and, eventually, establish and guide treatment strategies toward a better therapeutic outcome in lipedema patients. METHODS: 25 patients with lipedema and ten healthy controls with no history of lipedema were included in this study. All ultrasound examinations were performed on a novel high-performance ultrasound system (Resona R9/Mindray) using CDFI and the UMA technique. RESULTS: In all of the patients, Ultra Micro Angiography achieved the excellent visualization of microvascular structures, revealing that most lipedema patients showed grade 3 (n = 13) or grade 2 (n = 8) flow. UMA was superior to CDFI for depicting the microvascular structures. CONCLUSIONS: Here we show that UMA imaging characterizes the subcutaneous microvasculature with an unprecedented accuracy. The method has the advantage of being sensitive to small, slow-flowing vessels. This allows for the assessment of the course of vessels and vascular pathologies in great detail. Thus, UMA as a non-invasive diagnostic method can improve diagnostic accuracy in lipedema.

Differentiation of lipoedema from bilateral lower limb lymphoedema by imaging assessment of indocyanine green lymphography.

Lipoedema is characterized by disproportionate painful fat accumulation mostly in the lower limbs. The presence of lymphoedema in lipoedema remains controversial. This study aimed to assess the presence or absence of lymphoedema in the lower limbs of women with lipoedema using indocyanine green (ICG) lymphography. A cross-sectional retrospective study was undertaken in women with a clinical diagnosis of lipoedema whose lower limbs were examined with ICG lymphography. MD Anderson Cancer Center (MDACC) ICG staging was used to determine lymphoedema presence and severity. Patient characteristics, ICG lymphography findings, Stemmer sign, body mass index, waist-to-hip ratio, limb volume and bioimpedance spectroscopy measures were recorded. Forty women with lipoedema underwent ICG lymphography for the lower limbs from January 2018 to July 2022. Thirty-four women (85.0%) were determined by ICG lymphography as MDACC ICG Stage 0 representing normal lymphatics. Of the six women who demonstrated dermal backflow on ICG lymphography, all were determined as ICG Stage 1, four had localized traumatic dermal backflow area at their ankles, one had previously diagnosed with primary lymphoedema and one was classified as lipoedema stage 4. ICG lymphography findings suggested the absence of lymphoedema in a clear majority of women with lower limb lipoedema.

Subcutaneous Adipose Tissue Edema in Lipedema Revealed by Noninvasive 3T MR Lymphangiography.

BACKGROUND: Lipedema exhibits excessive lower-extremity subcutaneous adipose tissue (SAT) deposition, which is frequently misidentified as obesity until lymphedema presents. MR lymphangiography may have relevance to distinguish lipedema from obesity or lymphedema. HYPOTHESIS: Hyperintensity profiles on 3T MR lymphangiography can identify distinct features consistent with SAT edema in participants with lipedema. STUDY TYPE: Prospective cross-sectional study. SUBJECTS: Participants (48 females, matched for age [mean = 44.8 years]) with lipedema (n = 14), lipedema with lymphedema (LWL, n = 12), cancer treatment-related lymphedema (lymphedema, n = 8), and controls without these conditions (n = 14). FIELD STRENGTH/SEQUENCE: 3T MR lymphangiography (nontracer 3D turbo-spin-echo). ASSESSMENT: Review of lymphangiograms in lower extremities by three radiologists was performed independently. Spatial patterns of hyperintense signal within the SAT were scored for extravascular (focal, diffuse, or not apparent) and vascular (linear, dilated, or not apparent) image features. STATISTICAL TESTS: Interreader reliability was computed using Fleiss Kappa. Fisher's exact test was used to evaluate the proportion of image features between study groups. Multinomial logistic regression was used to assess the relationship between image features and study groups. The odds ratio (OR) and 95% confidence interval (CI) of SAT extravascular and vascular features was reported in groups compared to lipedema. The threshold of statistical significance was P < 0.05. RESULTS: Reliable agreement was demonstrated between three independent, blinded reviewers (P < 0.001). The frequency of SAT hyperintensities in participants with lipedema (36% focal, 36% diffuse), LWL (42% focal, 33% diffuse), lymphedema (62% focal, 38% diffuse), and controls (43% focal, 0% diffuse) was significantly distinct. Compared with lipedema, SAT hyperintensities were less frequent in controls (focal: OR = 0.63, CI = 0.11-3.41; diffuse: OR = 0.05, CI = 0.00-1.27), similar in LWL (focal: OR = 1.29, CI = 0.19-8.89; diffuse: OR = 1.05, CI = 0.15-7.61), and more frequent in lymphedema (focal: OR = 9.00, CI = 0.30-274.12; diffuse: OR = 5.73, CI = 0.18-186.84). DATA CONCLUSION: Noninvasive MR lymphangiography identifies distinct signal patterns indicating SAT edema and lymphatic load in participants with lipedema. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 1.

Deep learning for standardized, MRI-based quantification of subcutaneous and subfascial tissue volume for patients with lipedema and lymphedema.

OBJECTIVES: To contribute to a more in-depth assessment of shape, volume, and asymmetry of the lower extremities in patients with lipedema or lymphedema utilizing volume information from MR imaging. METHODS: A deep learning (DL) pipeline was developed including (i) localization of anatomical landmarks (femoral heads, symphysis, knees, ankles) and (ii) quality-assured tissue segmentation to enable standardized quantification of subcutaneous (SCT) and subfascial tissue (SFT) volumes. The retrospectively derived dataset for method development consisted of 45 patients (42 female, 44.2 ± 14.8 years) who underwent clinical 3D DIXON MR-lymphangiography examinations of the lower extremities. Five-fold cross-validated training was performed on 16,573 axial slices from 40 patients and testing on 2187 axial slices from 5 patients. For landmark detection, two EfficientNet-B1 convolutional neural networks (CNNs) were applied in an ensemble. One determines the relative foot-head position of each axial slice with respect to the landmarks by regression, the other identifies all landmarks in coronal reconstructed slices using keypoint detection. After landmark detection, segmentation of SCT and SFT was performed on axial slices employing a U-Net architecture with EfficientNet-B1 as encoder. Finally, the determined landmarks were used for standardized analysis and visualization of tissue volume, distribution, and symmetry, independent of leg length, slice thickness, and patient position. RESULTS: Excellent test results were observed for landmark detection (z-deviation = 4.5 ± 3.1 mm) and segmentation (Dice score: SCT = 0.989 ± 0.004, SFT = 0.994 ± 0.002). CONCLUSIONS: The proposed DL pipeline allows for standardized analysis of tissue volume and distribution and may assist in diagnosis of lipedema and lymphedema or monitoring of conservative and surgical treatments. KEY POINTS: • Efficient use of volume information that MRI inherently provides can be extracted automatically by deep learning and enables in-depth assessment of tissue volumes in lipedema and lymphedema. • The deep learning pipeline consisting of body part regression, keypoint detection, and quality-assured tissue segmentation provides detailed information about the volume, distribution, and asymmetry of lower extremity tissues, independent of leg length, slice thickness, and patient position.

Body Composition Assessment by Dual-Energy X-Ray Absorptiometry: A Useful Tool for the Diagnosis of Lipedema.

INTRODUCTION: Lipedema is a poorly known condition. Diagnosis is based almost exclusively on clinical criteria, which may be subjective and not always reliable. This study aimed to investigate regional body composition (BC) by dual-energy X-ray absorptiometry (DXA) in patients with lipedema and healthy controls and to determine cut-off values of fat mass (FM) indices to provide an additional tool for the diagnosis and staging of this condition. METHODS: This study is a single-center case-control study performed at Lausanne University Hospital, Switzerland. Women with clinically diagnosed lipedema underwent regional BC assessment by DXA. The control group without clinical lipedema was matched for age and body mass index (BMI) at a ratio of 1:2 and underwent similar examination. Regional FM (legs, arms, legs and arms, trunk, android and gynoid FM) was measured in (kg) and divided by FM index (FMI) (kg/m2) and total FM (kg). The trunk/legs and android/gynoid ratios were calculated. For all indices of FM distribution showing a significant difference between cases and controls, we defined the receiver operating characteristic (ROC) curves, calculating the area under the curve (AUC), sensitivity, specificity, and Youden's index. Types and stages of lipedema were compared in terms of FM indices. Correlation analyses between all FM distribution indices and lipedema stages were performed. RESULTS: We included 222 women (74 with lipedema and 148 controls). Overall, the mean age was 41 years (standard deviation [SD] 11), and mean BMI was 30.9 kg/m2 (SD 7.6). A statistically significant difference was observed for all DXA-derived indices of FM distribution between groups, except for arm FM indices. The ROC curve analysis of leg FM/total FM, as a potential indicator of lipedema, resulted in an AUC of 0.90 (95% confidence interval 0.86-0.94). According to Youden's index, optimal cut-off value identifying lipedema was 0.384. Sensitivity and specificity were 0.95 and 0.73, respectively. We found no significant differences between lipedema types and stages in terms of FM indices, nor significant correlations between the latter and lipedema stages. DISCUSSION/CONCLUSION: BC assessment by DXA, and particularly calculation of the leg FM/total FM index, is a simple tool that may help clinicians rule out lipedema in doubtful cases.

Lymphatic function and anatomy in early stages of lipedema.

OBJECTIVE: Lipedema is an inflammatory subcutaneous adipose tissue disease that develops in women and may progress to lipolymphedema, a condition similar to lymphedema, in which lymphatic dysfunction results in irresolvable edema. Because it has been shown that dilated lymphatic vessels, impaired pumping, and dermal backflow are associated with presymptomatic, cancer-acquired lymphedema, this study sought to understand whether these abnormal lymphatic characteristics also characterize early stages of lipedema prior to lipolymphedema development. METHODS: In a pilot study of 20 individuals with Stage I or II lipedema who had not progressed to lipolymphedema, lymphatic vessel anatomy and function in upper and lower extremities were assessed by near-infrared fluorescence lymphatic imaging and compared with that of a control population of similar age and BMI. RESULTS: These studies showed that, although lower extremity lymphatic vessels were dilated and showed intravascular pooling, the propulsion rates significantly exceeded those of control individuals. Upper extremity lymphatics of individuals with lipedema were unremarkable. In contrast to individuals with lymphedema, individuals with Stage I and II lipedema did not exhibit dermal backflow. CONCLUSIONS: These results suggest that, despite the confusion in the diagnoses between lymphedema and lipedema, their etiologies differ, with lipedema associated with lymphatic vessel dilation but not lymphatic dysfunction.

Indocyanine green lymphography as novel tool to assess lymphatics in patients with lipedema.

OBJECTIVE: Lipedema is a chronic and progressive disease associated with lymphatic impairment at later stages. The aim of our study was to describe the functional status and anatomy of lower limb superficial lymphatic system using indocyanine green (ICG) lymphography in patients with lipedema. METHODS: Following ICG injection at the dorsum of the foot, distance (cm) covered by the dye at 10 (T10') and 25 min (T25') was measured and normalized for limb length. If the dye did not reach the groin within 25 min, patients were classified as "drainage-needing" group (DNG). Values of fat and lean distribution assessed by dual-energy X-ray absorptiometry were extracted, and correlation analysis was performed. Furthermore, anatomical patterns of superficial lymphatics were assessed. RESULTS: Overall, 45 women were included, 25 (56%) of whom were classified as DNG. Symptoms duration was significantly associated with DNG status at multivariate analysis (odds ratio 1.07; 95% CI 1.01-1.14; p = 0.047). Moreover, Spearman's analysis showed a negative correlation between symptoms duration and T25' dye migration (r = -0.469; p = 0.037). Overall, no major anatomical lymphatic changes were found. CONCLUSIONS: Present study suggests that lymphatic functioning in patients with lipedema correlates with symptoms duration. Further research on larger cohorts should verify our findings and clarify their potential therapeutic implications. Overall, ICG lymphography may be promising technique to assess both lymphatic anatomy and functioning in patients with lipedema.

Ultrasound criteria for lipedema diagnosis.

BACKGROUND: Lipedema is characterized by the deposition of abnormal fat in the lower and upper limbs bilaterally. It is a disease with high prevalence and genetic characteristics. Non-specific and non-quantified increases in the thickness of the subcutaneous tissue have previously been demonstrated using magnetic resonance imaging and computed tomography. OBJECTIVES: To evaluate the thickness of the dermis and subcutaneous tissue in predetermined areas as a distinguishing feature between individuals with and without lipedema using ultrasound. METHODS: Ultrasound images of 89 female patients were analyzed, including patients undergoing clinical investigation for venous insufficiency or lipedema who underwent ultrasound evaluations at our institution. Patients were divided in two groups: with lipedema clinically diagnosed and those without lipedema. They underwent a common Doppler protocol for venous mapping to assess venous insufficiency associated with the evaluation of dermis and subcutaneous thickness at pre-defined points of the lower limbs. RESULTS: There were 63 patients with lipedema. Anterior thigh, pre-tibial and lateral aspect of the leg and supra-just medial malleolar region were significantly different. Supra-just medial malleolar region was significantly different with BMI above 25. An optimal cutoff value was calculated for the ultrasound diagnosis of lipedema using thickness of the dermis and subcutaneous tissues. CONCLUSIONS: Studied criteria allow use of simple and reproducible ultrasound cutoff values to diagnose lipedema in the lower limbs. Pre-tibial region thickness measurement, followed by thigh and lateral leg thickness are recommended for the ultrasound diagnosis of lipedema.

Lower extremity lymphatic function predicted by body mass index: a lymphoscintigraphic study of obesity and lipedema.

BACKGROUND/OBJECTIVES: Patients with obesity and lipedema commonly are misdiagnosed as having lymphedema. The conditions share phenotypic overlap and can influence each other. The purpose of this study was to delineate obesity-induced lymphedema, obesity without lymphedema, and lipedema in order to improve their diagnosis and treatment. SUBJECTS/METHODS: Our Lymphedema Center database of 700 patients was searched for patients with obesity-induced lymphedema (OIL), obesity without lymphedema (OWL), and lipedema. Patient age, sex, diagnosis, cellulitis history, body mass index (BMI), and treatment were recorded. Only subjects with lymphoscintigraphic documentation of their lymphatic function were included. RESULTS: Ninety-eight patients met inclusion criteria. Subjects with abnormal lymphatic function (n = 46) had a greater BMI (65 ± 12) and cellulitis history (n = 30, 65%) compared to individuals with normal lymphatic function [(BMI 42 ± 10); (cellulitis n = 8, 15%)] (p < 0.001). Seventeen patients had a history of lipedema and two exhibited abnormal lymphatic function (BMI 45, 54). The risk of having lower extremity lymphedema was predicted by BMI: BMI < 40 (0%), 40-49 (17%), 50-59 (63%), 60-69 (86%), 70-79 (91%), ≥80 (100%). Five patients with OIL (11%) underwent resection of massive localized lymphedema (MLL) or suction-assisted lipectomy. Three individuals (18%) with lipedema were treated with suction-assisted lipectomy. CONCLUSIONS: The risk of lymphedema in patients with obesity and lipedema can be predicted by BMI; confirmation requires lymphoscintigraphy. Individuals with OIL are at risk for cellulitis and MLL. Patients with a BMI > 40 are first managed with weight loss. Excisional procedures can further reduce extremity size once BMI has been lowered.

Lipedematous scalp. A rare entity in the pediatric ageLipedema de cuero cabelludo: una entidad infrecuente en pediatría.

Lipedematous scalp is an uncommon entity of unknown etiology, rarely described in the pediatric age. It is characterized by boggy thickening of the scalp predominantly located at the vertex and occiput, which acquires a cotton-like consistency. This condition is palpable rather than visible. It is a casual finding because it is usually asymptomatic, although it may involve alopecia, pruritus, or dysesthesia. We report a 10-year-old girl with lipedematous scalp without alopecia. Sonographic and MRI findings confirmed the diagnosis of lipidematous scalp.  El lipedema de cuero cabelludo o cuero cabelludo lipedematoso es una entidad infrecuente y de etiología desconocida, rara vez descrita en la edad pediátrica. Se caracteriza por un engrosamiento difuso y de tacto esponjoso del tejido celular subcutáneo localizado principalmente en vértex y occipucio. Suele ser un hallazgo casual dado que habitualmente cursa de forma asintomática, aunque puede asociar alopecia, prurito o disestesias. Presentamos el caso de una niña de 10 años de edad con lipedema de cuero cabelludo sin alopecia asociada. Los hallazgos ecográficos y de resonancia magnética confirmaron el diagnóstico de lipedema de cuero cabelludo.

Non-contrast MR Lymphography of lipedema of the lower extremities.

AIM: To assess imaging findings and characteristics of the lymphatic system in patients affected by lipedema and lipolymphedema of the lower extremities on Non-Contrast MR Lymphography (NCMRL). MATERIALS AND METHODS: 44 lower extremities in 11 consecutive female patients affected by lipedema, and 11 patients with lipolymphedema were examined by NCMRL. MR imaging was performed on 1.5-T system MR equipment. The examination consisted of one 3D short-tau inversion recovery (STIR) and one heavily T2-weighted 3D-Turbo Spin Echo (TSE) sequence. RESULTS: All patients showed symmetrical enlargement of the lower extremities with increased subcutaneous fat tissue. The fat tissue was homogeneous, without any signs of edema in pure lipedema patients. In all the extremities with lipolymphedema, high signal intensity areas in the epifascial region could be detected on the 3D-TSE sequence (p < .001) with evidence of mild epifascial fluid collections (p < .001). No sign of honeycomb pattern fat appearance was observed. The appearance of the iliac lymphatic trunks was normal in both lipedema and lipolymphedema patients. Dilated peripheral lymphatics were observed in 2 patients affected by lipedema, indicating a subclinical status of lymphedema, and in 10 patients with lipolymphedema (p = .001). Signs of vascular stasis were observed in both groups, without statistically significant difference (p = .665). CONCLUSION: NCMRL is a non-invasive imaging technique that is suitable for the evaluation of patients affected by lipedema and lipolymphedema, helping in the differential diagnosis.

The impact of lower body compression garment on left ventricular rotational mechanics in patients with lipedema-Insights from the three-dimensional speckle tracking echocardiographic MAGYAR-Path Study.

Lipedema is a lymphedema-masquerading symmetrical, bilateral and disproportional obesity. Its conservative maintenance treatment comprises the use of flat-knitted compression pantyhoses. Lipedema is known to be associated with left ventricular morphological and functional alterations. The present study aimed to assess the effects of graduated compression stockings on left ventricular (LV) rotational mechanics measured by three-dimensional speckle-tracking echocardiography (3DSTE) in lipedema patients. The present study comprised twenty lipedema patients (mean age: 45.8 ± 11.0 years, all females) undergoing 3DSTE who were also compared to 51 age- and gender-matched healthy controls (mean age: 39.8 ± 14.1 years, all females). 3DSTE analysis was performed at rest, and subsequent to 1 hour application of compression class 2 made-to-measure flat-knitted pantyhose. Six lipedema patients showed significant LV rotational abnormalities. Of the remaining fourteen lipedema patients LV basal rotation rotation showed significant reduction, while LV apical rotation showed significant increase with unchanged LV twist after a 60-minute use of compression garment. Significant changes in LV rotational mechanics could be detected among 14 women with lipedema after the use of compression garment however six probands have special LV rotational abnormalities at baseline and/or after compression.

Are increased left ventricular strains compensatory effects in lipedema? Detailed analysis from the three-dimensional speckle-tracking echocardiographic MAGYAR-Path Study.

PURPOSE: Lipedema is a chronic, common but underdiagnosed disease masquerading obesity, with female predominance, characterized by disproportional abnormal adipose tissue distribution of the lower and also upper extremities. The present study was designed to determine whether lipedema is associated with three-dimensional (3D) speckle-tracking echocardiography (3DSTE)-derived left ventricular (LV) deformation abnormalities, and to assess the effects of 1-hour use of medical compression stockings (MCS). METHODS: The present study comprised 19 female patients with lipedema (mean age: 42.2 ± 12.4 years), compared to 28 age-matched healthy female controls (mean age: 42.0 ± 9.8 years). RESULTS: Lipedema patients showed larger left atrial and LV dimensions and greater LV ejection fraction than controls, without significant difference in other echocardiography variables. Lipedema patients had greater 3DSTE-derived global and mean segmental LV circumferential and area strains than controls. Following 1-hour use of wearing MCS, neither global and nor mean segmental LV strains showed significant impairment or improvement. CONCLUSIONS: Increased LV strains could be compensatory effects maintaining LV pumping function in lipedema. Short-term wearing of MCS has no global effect on LV strains.

Uncovering Lymphatic Transport Abnormalities in Patients with Primary Lipedema.

BACKGROUND: Although lipedema is often clinically distinguished from lymphedema, there is considerable overlap between the two entities. The purpose of this study was to evaluate lymphoscintigraphic findings in patients with lipedema to better characterize lymphatic flow in this patient population. METHODS: Patients with lipedema receiving lymphoscintigraphy between January 2015 and October 2017 were included. Patient demographics, clinical characteristics, and lymphoscintigraphic findings were extracted. Klienhan's transport index (TI) was utilized to assess lymphatic flow in patient's lower extremities (LEs).Scores ranged from 0 to 45, with values > 10 denoting pathologic lymphatic transport. RESULTS: A total of 19 total patients with lipedema underwent lymphoscintigraphic evaluation. Mean age was 54.8 years and mean body mass index was 35.9 kg/m2. Severity of lipedema was classified as stage 1 in five patients (26.3%), stage 2 in four patients (21.1%), stage 3 in four patients (21.1%), and stage 4 in six patients (31.6%). The mean TI for all extremities was 12.5; 24 (63.2%) LEs had a pathologic TI, including 7 LEs with stage 1 (29.2%), 3 LEs with stage 2 (12.5%), 6 LEs with stage 3 (25.0%), and 8 LEs with stage 4 lipedema (33.3%). The mean TI was significantly greater for extremities with severe (stage 3/4) lipedema than those with mild or moderate (stage 1/2) lipedema (15.1 vs. 9.7, p = 0.049). Mean difference in TI scores between each LE for individual patients was 6.43 (standard deviation +7.96). CONCLUSION: Our results suggest that patients with lipedema have impaired lymphatic transport, and more severe lipedema may be associated with greater lymphatic transport abnormalities.