Purpose: To assess the role of heavily T2-weighted image and interstitial MR lymphangiography (MRL) for the visualization of lymphatic vessels in patients with disorders of the lymphatic circulation.
Methods: Forty lower extremities in 31 patients (9 bilateral and 22 unilateral) with primary lymphedema were examined by heavily T2-weighted image and indirect MRL. Maximum-intensity projection (MIP) was used to reconstruct the images of the lymphatic system. Two experienced radiologists analyzed the images with regard to the differences in image quality, number of lymphatic vessels, its maximum diameter and two other findings: accumulated lymph fluid in the tissue and honeycombing pattern.
Results: The beaded appearance of the affected vessels in 73 leg segments of 40 lower extremities were present on both modalities 3D MIP. Larger amount of the dilated lymphatic vessels were visualized on heavily T2-weighted image than that on MRL (p=0.003) and the maximum diameter of it was 4.28+/-1.53mm on heavily T2-weighted image, whereas 3.41+/-1.05mm on MRL (p<0.01). The dilated lymphatic vessels on MRL showed better image quality and greater SNR and CNR than that on heavily T2-weighted image (p<0.01). The regions of accumulated lymph fluid and the honeycombing pattern extent were identified on heavily T2-weighted image scored statistically higher than that on MRL (p<0.01).
Conclusion: The heavily T2-weighted imaging has greater sensitivity and the MRL image has higher legibility for detecting the pathologically modified lymphatic vessels and accompanying complications non-invasively. Combining these two MR techniques can accurately access the pathological changes in the lower extremity with lymphedema.
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