LAUSR

Lipedema as one of rare adipose disorders 1 is characterized by excessively deposited subcutaneous adipose tissue (SAT) especially in the lower extremities, which has a distinctive female predilection and is often clinically misdiagnosed as obesity as well as ignored prior to the already distinct presence of lymphedema. The persistent exploration of lipedema as a conspicuous clinical existence from obesity is pressing considering that many patients have concomitant lipedema and obesity. When lymphatic load is beyond lymphatic transport capability resulted from a dynamic or mechanical dysfunction, adipose tissue edema and excess lymph load in lipedema may be disorganized. If left untreated, progressive edema may lead to lymphatic failure and ultimately further the presence of lymphedema. The detection or diagnosis of tissue edema in patients with lipedema as early as possible is clinically of great importance to provide treatments in good time like compression and technical lymphatic drainage earlier during the development of the disease. Besides the amelioration in discriminating lipedema from obesity with an eye toward diagnostic criteria, histology, and pathophysiology of lipedema, more important endeavor is no doubt much needed in developing novel imaging biomarker to potentially provide preventative treatments that may delay or obstruct lymphedema origination in lipedema. An essential obstacle to lipedema regulation is a shortage of reliable and effective biomarkers of the condition. Discriminating lipedema from primary or secondary lymphedema and obesity is out of question a key step for clinical diagnosis in professional medical institutions. MRI measurements of tissue fat content have potential to aid in differential diagnosis of lipedema from obesity. One prior endeavor of finding imaging biomarker without exogenous contrast agents has demonstrated the feasibility of performing 3T lymphangiography of the upper extremity lymph stasis noninvasively using a specialized sequence protocol based on turbo-spin-echo (TSE) MR pulse sequences within clinically acceptable detection time of roughly 10 minutes. This MR imaging methodology is mainly based on heavily T2-weighted TSE sequences using the long T2 relaxation time of lymph (T2 = 610 msec) in relation to blood and muscle (T2 = 30–120 msec), and a multi-pulse refocusing train to dephase fast flowing blood signal while maintaining slower flowing signal from lymphatic fluid. In this issue of JMRI, an article by Crescenzi et al advances our understanding of imaging features of noninvasive 3T magnetic resonance lymphangiography based on the aforementioned work, in which a proposed non-contrast agent noninvasive MR lymphangiography methodology uncovers distinct signal patterns indicating SAT edema and increased lymphatic load in participants with lipedema suggestive of relevance to radiological diagnosis and surveillance of edema in lipedema. In particular, to nullify the signal from fast flowing arterial and venous blood-water spins flowing into the field of view, regional saturations followed by dephasing gradients are applied. And on the basis of the published work, the long-TSE refocusing pulse train indicated that TSE-factors >40 (shot duration ~528 msec) were sufficient to maintain signal from lymphatic fluid in comparison to residual blood-water signal. One limitation of the current work is the relatively small sample sizes in each enrolled subject subgroup being imaged and analyzed, say, the subgroup number of cancer treatment-related lymphedema (lymphedema, n = 8). The insufficiency in involved sample sizes may more or less impact on both the statistical reliability and sufficiency of evidence in better and effectively delineating the specificity of MR lymphangiography to interstitial fluid clearance and the lymphatic network. Much work remains to be done to determine the relevance of MR lymphangiography for radiological diagnosis protocols for lipedema and surveillance for persistent edema in lipedema so as to timely guide provision in clinical health care. Anyway, the work by Crescenzi et al of this issue is