MRI or ultrasonography may improve clinicians’ abilities to accurately identify Achilles tendon xanthoma (ATX) in patients with familial hypercholesterolemia (FH), although the small amount of supporting evidence is low-quality, according to a study published in the Journal of Clinical Lipidology.
ATX is associated with a higher patient risk of cardiovascular events and more severe cases of coronary artery disease. In the current study, researchers systematically reviewed published studies that included MRI or ultrasound imaging of ATX in patients with FH as well as a control group of participants without FH, with or without symptomatic tendons.
Their goal was to evaluate the accuracy of MRI and ultrasound imaging in identifying cases of ATX in this subgroup. All eligible studies were reviewed using the Standards for the Reporting of Diagnostic accuracy (STARD) checklist and a qualitative synthesis.
A total of 699 patients with FH and 868 without from 15 published studies were included for analysis. Ultrasound-based tendon thickening was the most common diagnostic criterion studied, but the range of cutoff values proposed for the measurements varied widely, and the 5 studies examining ultrasound’s ability to differentiate patients with FH from healthy controls estimated sensitivity ranging from 71% to 97% and specificity from 78% to 91%.
There was no consensus on diagnostic cut-points for tendon thickness in the studies regarding the usefulness of MRI for identifying ATX, with measurements ranging from 5.5 to 10 mm. STARD checklist evaluations suggested that evidence quality was low in all included studies.
Study investigators concluded that “[a] small amount of low-quality evidence suggests that ultrasonography has the potential to improve the diagnosis of ATX in people with FH, thereby identifying patients at high risk of cardiovascular catastrophes. Further research is warranted, particularly in the development of new techniques capable of specifically quantitating tendon cholesterol accumulation.”
Scott A, Zahradnik TM, Squier K, Beck C, Brunham LR. Diagnostic accuracy of ultrasound and MRI for Achilles tendon xanthoma in people with familial hypercholesterolemia: a systematic review [published online November 7, 2018]. J Clin Lipidol. doi: 10.1016/j.jacl.2018.10.013