Magnetic resonance imaging of Achilles tendon xanthomas in familial hypercholesterolemia

Abstract

The demonstration of tendon xanthomas is helpful in diagnosing heterozygous familial hypercholesterolemia, but in many patients lipid may accumulate without clinical abnormality being present. We investigated the possibility of detecting the lipid element with magnetic resonance (MR) imaging in seven patients with familial hypercholesterolemia and six controls. Although the mean relative signal intensities measured on long TR/TE spin echo sequences of the tendon were significantly higher in patients than in controls, the lack of such elevation does not rule out the presence of such lesions. In vitro measurements indicated that the signal intensity of triglycerides was quenched by cholesterolesters. The anatomic findings of MR imaging were compared with those of ultrasonography (US), showing excellent correlation in measurements between MR images and US [r(S) = 0.95 and 0.97 respectively]. MR imaging and US provide equal information on the anatomy of the Achilles tendon; as an abnormally increased signal intensity within the xanthoma on MRI was found in only a minority of our patients, the value of MRI in the demonstration of Achilles tendon xanthomas is limited when using conventional T1 and T2 spin echo sequences.

Anatomy of the Achilles tendon (tendo calcaneus) with respect to tendon thickness measurements

“…The plantaris tendon was identifiable at the dome of the talocrurat joint as a separate tendon on both sides in 44%, on one side only in 23%, and not identifiable in 33%. In about 2/3 of the cases in which it was not 6.2 ± 0.9 (athletes) Yuzava et al [14] 4.2 ± 0.5 (women) Japanese 7.5 MHz 4.7 +_ 0.4 (men) Liem et al [11] 6.2 ± 1.2 Dutch Not indicated…”

“…The vulnerability of the tendon complex precludes taking of repeated tissue samples for diagnostic purposes. Ultrasonic measurement of the tendon thickness has been proposed as a useful, non-invasive tool for detecting and monitoring cholesterol accumulation in familial hypercholesterotemia (FH) [2,4,8,9,11,13,14] and beta-2-microglobulin accumulation in hemodialysisrelated amyloidosis [7]. The normal mean values reported for achilles tendon thickness measurements differ considerably (from 4.2 to 7.1 mm) in different studies [4, 5, 6, 9, 10, 11, …”

Avaliação morfométrica do tendão de Aquiles por ultra-sonografia

“…The average normal values reported regarding Achilles tendon diameters vary considerably in different studies (8,(26)(27)(28)(29)(30)(31) . And, considering the discordance between the average values found in our casuistic and those reported by the majority of studies in the literature, our conclusion is that the standardization and application of tables specific for our population is of great importance in the daily clinical practice.…”

Real-time spatial compound sonography of Achilles tendon in patients with heterozygous familial hypercholesterolaemia and normal physical examination

“…This last limitation is shared by computed tomography (CT) which, while providing accurate measurement of tendon size thanks to the intrinsic contrast between Achilles tendon and the surrounding fat, is unable to measure density values that differ substantially in patients with normal and elevated cholesterol levels [16]. Magnetic resonance imaging (MRI) is only able to detect changes in shape and size and a nonspecific "pointed" appearance but cannot demonstrate lesions unequivocally referable to tendon xanthomas [20][21][22].…”