Abstract
BackgroundFamilial 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.MethodsBilateral 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.ResultsFat 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).ConclusionMRI-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.
Highlights
Familial Hypercholesterolemia (FH) is the most commonly inherited cardiovascular disease (CVD), and is among the most common congenital metabolic disorders with a prevalence of 1:200 – 1:300 worldwide [1, 2] It is estimated that greater than 90% of those with FH have not been diagnosed [3]
Intratendinous deposits are most common in the Achilles tendon (ATX, Achilles tendon xanthoma) [5,6,7]
Mean baseline pre-treatment total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) were 9.46 mmol/L and 7.56 mmol/L, which decreased to TC of 5.23 mmol/L and LDL-C of 3.60 mmol/L with lipidlowering treatment
Summary
Familial Hypercholesterolemia (FH) is the most commonly inherited cardiovascular disease (CVD), and is among the most common congenital metabolic disorders with a prevalence of 1:200 – 1:300 worldwide [1, 2] It is estimated that greater than 90% of those with FH have not been diagnosed [3]. Intratendinous deposits are most common in the Achilles tendon (ATX, Achilles tendon xanthoma) [5,6,7]. ATX deposition triggers an inflammatory response within the Achilles tendon leading to symptoms very similar to Achilles tendinopathy (ATY) [8]. 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, in the Achilles. The main hypothesis was that Achilles tendon xanthomas will demonstrate greater lipid content than Achilles tendinopathy or healthy control tendons
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
