A Systematic Review Comparing Lymphoscintigraphy and Magnetic Resonance Imaging Techniques in the Assessment of Peripheral Lymphedema

Background Peripheral lymphedema represents a debilitating condition affecting the lymphatic system of the limbs resulting from impaired drainage and excessive lymphatic fluid accumulation in the interstitial spaces. Lymphoscintigraphy is the imaging modality of first choice to investigate patients with peripheral lymphedema. Nevertheless, in recent times, magnetic resonance imaging (MRI) techniques have also been applied to assess patients with lymphedema. Objective The present systematic review aims to appraise the evidence by providing a head-to-head comparison between lymphoscintigraphy and MRI techniques in peripheral lymphedema. Methods A systematic literature search was performed using the PubMed database and Cochrane Central Register of Controlled Trials (CENTRAL). The eligibility criteria for the articles to be included in the qualitative synthesis were: 1) a study cohort or a subset of patients with a clinical diagnosis of peripheral lymphedema (either upper or lower limb); 2) execution of both MR imaging and lymphoscintigraphy in the same subset of patients. The methodological quality of the studies was assessed by an investigator using the "Quality Assessment of Diagnostic Accuracy Studies" tool, v. 2 (QUADAS-2). Results Overall, 11 studies were ultimately included in the quantitative analysis. No meta-analysis was performed due to the heterogeneous patient samples, the different study aims of the retrieved literature, and the limited number of available articles. In the diagnosis of upper limb extremity lymphedema, the sensitivity of MRI techniques appears superior to that of lymphoscintigraphy. Comparative studies in the lower limbs are still scarce but suggest that MRI may increase the diagnostic accuracy for lymphedema. Conclusion The available literature on patients with lymphedema evaluated with both lymphoscintigraphy and MRI does not allow definite conclusions on the superiority of one imaging technique over the other. Further studies, including well-selected patient samples, are still necessary to compare the accuracy of these imaging modalities. Since MRI techniques seem to provide complementary findings to lymphoscintigraphy, it would be conceivable to acquire both imaging exams in patients with peripheral lymphedema. Furthermore, studies evaluating the clinical impact of adding MRl to the diagnostic workup are warranted.