DIAGNOSIS OF ACHILLES-TENDON XANTHOMA IN PATIENTS WITH HETEROZYGOUS FAMILIAL HYPERCHOLESTEROLEMIA - MR VS SONOGRAPHY

OBJECTIVE. The purpose of this study was twofold: (1) to determine the characteristic MR appearance of the xanthomatous tendons of heterozyg ous familial hypercholesterolemia and (2) to determine which of two im aging techniques, high-frequency linear-array sonography or MR imaging , is better for detection of xanthomas. SUBJECTS AND METHODS. Sonograp hy and MR imaging were performed to evaluate the Achilles tendons in 1 0 patients (20 tendons) with heterozygous familial hypercholesterolemi a. For sonography, 7.5- (nine patients) and 10.0- (one patient) MHz tr ansducers were used. T1-weighted, proton density-weighted, and T2-weig hted MR images were obtained at 0.5 T (four patients) and 1.5 T (six p atients), including fat-suppressed (six patients) and water-suppressed (one patient) T1-weighted images at 1.5 T. Tendon abnormalities detec ted with both techniques were noted, and the results were compared. RE SULTS. In all tendons, sonograms showed focal hypoechoic lesions compa tible with xanthomas. MR images did not show focal lesions. Instead, a ll pulse sequences showed a diffuse speckled or reticulated pattern or both on axial images. This speckled or reticulated appearance was mor e obvious on fat-suppressed T1-weighted images and much less evident o n water-suppressed T1-weighted images. Contrast resolution was subject ively better on sonograms than on MR images in all cases. CONCLUSION. The speckled or reticulated appearance is a characteristic, if not pat hognomonic, MR feature of xanthomatous tendons and probably is due to edema or inflammation, not intratendinous lipid. However, localized li pid deposits detected on sonograms are more readily quantified than ar e the lesions seen on MR images. Therefore, we think sonography, rathe r than MR imaging as performed in our study, is the technique of choic e for detecting xanthomas.