Can Achilles tendon xanthoma be distinguished from Achilles tendinopathy using Dixon method MRI? A cross-sectional exploratory study

Abstract

Background Familial hypercholesterolemia is a genetic condition characterized by life-long elevations of plasma low-density lipoprotein cholesterol. In addition to life-threatening cardiovascular complications, intratendinous cholesterol deposits (xanthomas) can lead to pain and tendon thickening, particularly in the Achilles. Clinical detection of xanthomas currently relies upon visual assessment and palpation, or ultrasound-based measures of tendon thickening or echotexture. Misdiagnosis of xanthoma can delay the commencement of potentially life-saving lipid-lowering therapy. Our primary purpose was to determine whether analysis of separated fat and water magnetic resonance images may be able to differentiate between xanthomatic and nonxanthomatic Achilles tendons through quantification of intratendinous fat content. The main hypothesis was that Achilles tendon xanthomas will demonstrate greater lipid content than Achilles tendinopathy or healthy control tendons. Methods Bilateral MRI scans of Achilles tendons from 30 participants (n = 10 Achilles tendon xanthoma, n = 10 Achilles overuse tendinopathy, n = 10 healthy controls) were analyzed for total lipid content using the Dixon method of fat and water signal separation. Secondary outcome measures included tendon water content, as well as ultrasound characterization of tendon tissue organization and thickness. Results Fat content was greater in Achilles tendon xanthomas compared to the tendinopathy (p < 0.0001) and control groups (p < 0.0001). Water content was also greater in Achilles tendon xanthomas compared to the tendinopathy (p < 0.0001) and control groups (p = 0.0002). Ultrasound tissue characterization revealed worse tissue organization in Achilles tendon xanthoma tendons compared to Achilles tendinopathy (p < 0.05) but demonstrated largely overlapping distributions. Achilles tendon xanthoma tendons were, on average, significantly thicker than the tendons of the other two groups (p < 0.01 and p < 0.001, respectively). Conclusion MRI-derived measures of Achilles tendon fat content may be able to distinguish xanthomas from control and tendinopathic tissue. Dixon method MRI warrants further evaluation in an adequately powered study to develop and test clinically relevant diagnostic thresholds.

Test yourself answer to question: gradual enlargement of nodules in both ankles

“…1007/ s00256-022-04125-2 Medical history, physical examination, and biochemical tests can help. Moreover, Dixon MRI may be able to distinguish Achilles tendon xanthoma from overuse tendinopathy [9]. For common gout nodules, in addition to biochemical tests, ultrasonography and CT are also useful tools to detect monosodium urate depositions.…”

Presurgical Perspective and Postsurgical Evaluation of the Plantar Fascia

“…Small foci of increased T1 signal due to lipid deposits and trabeculated low-signal-intensity areas on T1- and T2-weighted images representing the remaining fascicles has been described. 66 Elevated fat content in xanthomas can be detected using Dixon MRI-derived measures that may distinguish xanthomas from other lesions such as tendinopathy or fibromas. 66 The heterogeneous signal characteristic of xanthomas has been described with a characteristic speckled or reticulated appearance on both T1- and T2-weighted axial images.…”

“…66 Elevated fat content in xanthomas can be detected using Dixon MRI-derived measures that may distinguish xanthomas from other lesions such as tendinopathy or fibromas. 66 The heterogeneous signal characteristic of xanthomas has been described with a characteristic speckled or reticulated appearance on both T1- and T2-weighted axial images. 67 A similar typical speckled appearance has also been described in plantar fascia xanthomas.…”

The Distal Free Achilles Tendon Is Longer in People with Tendinopathy than in Controls: A Retrospective Case-Control Study

“…Using magnetic resonance imaging (MRI), the structural differences can be investigated between those with and without tendinopathy [11,12]. It has been well established that those with tendinopathy have tendons with significantly larger cross-sectional area and anterior-posterior diameter compared to healthy controls [7,[13][14][15][16][17][18][19][20][21][22][23][24][25][26]. is is thought to be mainly due to the increased fluid content and disordered collagen structure as an adaptive and/or reparative response [27][28][29][30][31][32][33][34][35].…”