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

Abstract

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

Diagnostic imaging in lipedema: A systematic review

“…Eight studies reported on MRI and three studies compared lipedema and lipolymphedema patients 7,16,29–34 . Lohrman and Duewell et al 7,34 did not specify criteria for diagnosing lipedema.…”

Semiautomated segmentation of lower extremity MRI reveals distinctive subcutaneous adipose tissue in lipedema: a pilot study

“…Additional structural and molecular imaging techniques (e.g., high spatial-resolution T1- and T2-weighted MRI, sodium Na23-MRI, H1 relaxometry) and statistical image analysis approaches (e.g., texture quantification) are being investigated to develop discriminative, noninvasive MRI biomarkers of lipedema. Recently, vascular imaging revealed unique spatial patterns of fluid retention in lipedema SAT and could be incorporated into a multimodal imaging approach to disambiguate potential vascular etiology of SAT deposition 25 . The relationship of such radiological biomarkers to clinical symptomatology and functional impairments is also of interest to better understand the complex disease mechanisms of lipedema.…”

MRI of Lymphedema

“…These features seen on imaging exams allow for differentiation from other conditions like phlebedema or lipidema, which can be clinically challenging. [90][91][92] Grading systems that take into account the degree of fat and fluid contributions to extremity swelling in chronic lymphedema would assist in determining whether a patient could undergo debulking vs. direct lymphatic repair. 86 Microreconstruction planning can require a detailed assessment of regional lymph node characteristics and precise depiction of the lymphatic system including number, diameter, and location.…”

“…8). These features seen on imaging exams allow for differentiation from other conditions like phlebedema or lipidema, which can be clinically challenging 90–92 . Grading systems that take into account the degree of fat and fluid contributions to extremity swelling in chronic lymphedema would assist in determining whether a patient could undergo debulking vs. direct lymphatic repair 86 …”