Systematic Review of Magnetic Resonance Lymphangiography From a Technical Perspective

Area of Science:

• Medical Imaging
• Lymphatic System Research
• Diagnostic Techniques

Background:

• Current standards for lymphatic function assessment include clinical examination and lymphoscintigraphy.
• Magnetic resonance imaging (MRI) provides nonionizing, three-dimensional (3D) visualization of lymphatic vasculature.
• MRI enables functional assessments of lymphatic flow, potentially improving diagnosis and treatment planning for conditions like lymphedema.

Purpose of the Study:

• To review the utility of MRI as a noninvasive method for evaluating lymphatic drainage.
• To identify areas requiring further investigation in the field of MRI for lymphatic assessment.

Main Methods:

• A systematic literature search was conducted on PubMed in October 2019 to identify studies on magnetic resonance lymphangiography (MRL).
• No restrictions were placed on field strength or imaging sequences.
• Article quality was assessed using bespoke protocols, including the NIH quality assessment tool and the Downs and Blacks quality checklist.

Main Results:

• Out of 612 identified articles, 43 were included in the review, with their protocols and results summarized.
• Most studies utilized 1.5 or 3.0 Tesla (T) field strengths, with 58% employing 3.0 T.
• Commonly imaged areas include the peripheries, upper and lower limbs, pelvis, and trunk. T2-weighted and contrast-enhanced T1-weighted images are routinely used to visualize lymphatic vessels, with edema, vessel characteristics, and contrast uptake indicating lymphatic dysfunction.

Conclusions:

• MRL provides comprehensive, qualitative, and quantitative 3D imaging of the lymphatic vasculature.
• Emerging consensus exists on MRL protocol design despite study heterogeneity.
• Further optimization and research into protocol variations are necessary to fully realize MRL's potential in understanding lymphatics and detecting disease.