Evaluation of calcium pyrophosphate dihydrdeposition disease by ultrasound.

Objective: Our aim was to characterize the ultrasonographic features of patients with calcium pyrophosphate dihydrate (CPPD) deposition disease, and compare X-ray and ultrasound in evaluating CPPD deposition disease.
Methods: In this retrospective study, all 71 patients between 2004 and 2007 with CPPD deposition disease proved by microscopic synovial fluid analysis were enrolled. We collected and analyzed 38 patients of those, on whom both conventional X-ray and high-resolution ultrasound had been carried out.
Results: All patients were elderly (i.e. >65 y/o) and mostly coexisted with osteoarthritis. The involvement of knee joint was the most common site. Popliteal cyst was detected in 9 of 71 patients. Synovial fluid analysis of 38 patients with CPPD deposition disease revealed that the average total white cell count was 25592.1 ± 16697.8 /mm3, with significant neutrophil predominance. There was significant evidence that ultrasound was more reliable than X-ray in the diagnosis of CPPD deposition disease (p=0.002). Besides, there were no patients with CPPD deposition disease in whom X-rays suggested CPPD deposition disease, but for whom ultrasound results were negative.
Conclusion: We found that bright stippled foci in the synovial fluid or around the articular region, the thin hyperechoic band parallel to the surface of the hyaline cartilage, and the calcification of fibrocartilage seen on ultrasound could represent CPPD deposits. Our data showed that ultrasound is a useful and important tool in the diagnostic investigation of patients with CPPD deposition disease.