Article

Lipedema on ultrasound: how to measure and grade

Lipedema ultrasound technical guide: where to measure (6 to 8 cm above the medial malleolus), how to measure without compression, Amato cutoffs and Marshall grading.

Why measure lipedema on ultrasound

Lipedema is an abnormal and symmetrical accumulation of subcutaneous adipose tissue, typically in the lower limbs, which usually excludes the feet. The diagnosis is clinical, but ultrasound is an objective, cheap and reproducible method to measure the thickness of the subcutaneous cellular tissue (TCSC) and monitor the evolution throughout the treatment.

This page is an educational bridge: it shows where to place the transducer, how to avoid the most common mistake (compressing the skin), how to measure in a standardized way, what the cutoff points are and how to grade severity. The objective is for two exams of the same patient to reach similar numbers.

Where to measure: the four standardized points

The Amato protocol measures four points, bilaterally, with at least three measurements per point. They are reproducible because they are anchored in bony references, and not in an approximate position of the leg.

The medial supramalleolar point deserves special attention: it is what feeds Marshall's gravity grading. Mark 6 to 8 cm above the tip of the medial malleolus, on the inside of the leg.

• Anterior thigh — middle third of the anterior surface of the thigh
• Anterior pretibial region — proximal third, close to the tibial crest
• Lateral leg — middle third of the lateral face
• Medial supramalleolar region — 6 to 8 cm above the medial malleolus (Marshall point)

The technique: abundant gel, without compressing the skin

The subcutaneous tissue is compressible. If you support the transducer with force, the measured thickness drops and gravity is underestimated. Use a high-frequency linear transducer (7.5 to 13 MHz), soft tissue preset, and a generous layer of gel to attach without pressure, keeping the transducer perpendicular to the skin.

• Thick layer of gel between the transducer and the skin
• Perpendicular transducer, light support, without sinking into the subcutaneous tissue
• Look at the skin in the image: it should not be deformed inward
• Repeat the measurement at least three times and be suspicious if the values drop when pressing.

How to take action

Freeze a cross-sectional image with well-defined skin and fascia. Position one caliper on the surface of the dermis and the other on the muscular fascia, perpendicular to the layers. The measurement of lipedema is the combined thickness of the skin (cutis) and subcutaneous adipose tissue, from the dermis to the fascia.

• Always measure perpendicular to the layers (oblique measurement overestimates)
• Include from the dermis to the fascia (the skin is part of the measurement in the Marshall method)
• Avoid focal vessels and nodules when choosing the representative point
• Compare the sides: lipedema is usually symmetrical

Amato diagnostic thresholds

Amato et al. defined TCSC thickness thresholds, per point, above which the measurement suggests lipedema. The pretibial point was the one with the greatest diagnostic accuracy.

• Fore thigh: above 17.9 mm
• Anterior pretibial region: above 11.7 mm (greater accuracy)
• Side leg: above 8.4mm
• Medial supramalleolar region: above 7.0 mm

Marshall and Schwahn-Schreiber Gravity Graduation

Severity is graded by thickness in the medial supramalleolar region. For reference, a normal individual measures about 2.1 mm at this same point on the ankle.

When completing the report, include the corresponding degree, for example: findings compatible with moderate lipedema according to Marshall's severity classification. The measurements are in the body of the report; the conclusion carries the opinion and degree.

• 12 to 15 mm — mild lipedema (lipohyperplasia)
• 15 to 20 mm — moderate
• 20 to 30 mm — pronounced (unambiguous)
• above 30 mm — severe
• around 2.1 mm — normal reference (not lipedema)

Lipedema, lymphedema and obesity

Ultrasound helps to differentiate. In pure lipedema, the feet are spared, the skin has preserved thickness and there are no anechoic liquid sheets between the lobes in the early stages. Hyperechogenic nodular areas may appear in the subcutaneous layer.

• Lipedema: feet spared, symmetrical, without dermal thickening, pain on compression
• Lymphedema: affects the feet (Stemmer positive), dermal thickening and liquid layers
• Obesity: thickened subcutaneous tissue, but without the disproportion that spares the feet

Sources

This content is educational and does not replace the original publications or clinical correlation. Main references:

• Amato ACO et al. Ultrasound criteria for lipedema. Phlebology, 2021.
• Marshall M, Schwahn-Schreiber C. Prevalence of lipedema in professional women in Germany. Phlebologie, 2011.
• Naouri M et al. High-resolution cutaneous ultrasonography to differentiate lipoedema from lymphoedema. Br J Dermatol, 2010.

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