To investigate the diagnostic accuracy of ultrasound and conventional radiography in the evaluation of calcium pyrophosphate crystal deposits at wrist level.

Consecutive patients with a “definite” diagnosis of calcium pyrophosphate deposition disease and disease-controls were prospectively included in this cross-sectional single-centre study. Scapho-lunate ligament, triangular fibrocartilage complex, and volar recess of the radio-lunate joint were explored using ultrasound, conventional radiography and computed tomography.

Sixty one patients and 39 disease controls were enrolled. Two-hundred wrists were evaluated using both conventional radiography and ultrasound and 26 using computed tomography. Ultrasound findings indicative of crystal deposits were found in at least one wrist in 95.1% of patients and in 15.4% of controls (P<0.001). Scapho-lunate ligament calcifications were reported in 83.6% of patients and in 5.1% of controls (P<0.001). On conventional radiography, calcifications were found in at least one wrist in 72.1% of patients and in 0% of controls (P<0.001). Using the Ryan-McCarty criteria as a gold standard, sensitivity, specificity and diagnostic accuracy were 0.72 (0.59–0.83), 1.0 (0.91–1.0) and 0.83 (0.74–0.90) for conventional radiography and 0.95 (0.86–0.99), 0.85 (0.69–0.94) and 0.91 (0.84–0.96) for ultrasound. The agreement between ultrasound and computed tomography was substantial when assessing triangular fibrocartilage complex (kappa=0.70; 0.43–0.97) and scapho-lunate ligament (kappa=0.69; 0.41–0.97), and moderate for radio-lunate joint (kappa=0.46; 0.12–0.80).

This study supports the diagnostic accuracy of ultrasound in evaluating wrist involvement in calcium pyrophosphate deposition disease. The inclusion of the scapho-lunate ligament in a disease-oriented scanning protocol could improve the diagnostic performance of ultrasound.