Combined use of power Doppler and gray-scale sonography: A new technique for the assessment of inflammatory myopathy

Objective. Ultrasonography (US) is a utilitarian approach to the assessment of inflammatory myopathy (IM). Power Doppler sonography (PDS), a newer tec hnique, enables detection of muscle vascularity and inflammation. We descri be the combined use of PDS and gray-scale US in patients with IM. Methods. We studied 37 IM subjects and 6 control subjects. Clinical scores of muscle strength and function were obtained. The maximum score, 31, repre sented normal function and strength. UItrasonographic gray-scale and vascul arity results were scored 0-4. Nine subjects had serial assessments. Results. Subjects ranged from 16 to 83 years of age and were predominantly female. LM subjects had significantly abnormal lower clinical scores than c ontrols, 23.0 +/- 5.8 vs 29.8 +/- 2.0 (p < 0.001). Mean peak gray-scale sco re was 2.1 +/- 0.96 compared to 0.5 +/- 0.84 for controls (p = 0.001), indi cating atrophy in the IM group. Similar results were found for average gray -scale scores. Peak vascularity scores were higher in IM, 2.7 +/- 0.8 vs 2. 2 +/- 0.3 (p = 0.007). Disease of longer duration was significantly associa ted with more abnormal gray-scale scores and lower creatine phosphokinase ( CPK) levels. PDS scores were more abnormal in disease of shorter duration. There was a negative association between functional scores and inflammatory scores on serial assessment. Conclusion, Sonography is a valuable tool in the assessment of IM. Gray-sca le and PDS findings were significantly different between IM and control sub jects. Abnormal gray-scale US scores were associated with disease of longer duration and lower CPK levels. In contrast, increased vascularity on PDS d etected disease of shorter duration and varied with the clinical course mor e than did gray-scale findings.