Evaluation of tubulointerstitial injury by Doppler ultrasonography in glomerular diseases

Abstract

Aims: While Doppler ultrasonography is used commonly in various renal diseases, its clinical value in diagnosis of renal parenchymal diseases, especially glomerular diseases, remains controversial. We investigated whether Doppler ultrasonography in glomerular diseases could discriminate tubulointerstitial lesions, which correlated closely with long-term prognosis for renal function.

Methods: Sixty patients with primary or secondary glomerular diseases were examined by Doppler ultrasonography immediately before renal biopsy. The resistive index was calculated, as was the atrophic index (a newly proposed parameter defined as renal sinus length/renal length). These were compared with histologic changes in biopsy specimens.

Results: Receiver operator characteristic analysis showed a resistive index of 0.65 to be the optimal for discriminating tubulointerstitial changes with specificity of 100% and sensitivity of 57.1%. Tubulointerstitial injury scores were significantly higher in patients with resistive indices exceeding 0.65 than in patients with a lower value. An atrophic index of 0.70 was also shown to be optimal with specificity 100% and sensitivity 61.9%. In combination, the 2 indices showed improved sensitivity; when the patients were divided into groups where both resistive and atrophic indices were normal (respectively < or = 0.65 and < or = 0.70) or where either or both were high, sensitivity rose to 85.7%, while specificity remained 94.4%.

Conclusions: In combination, the resistive and atrophic indices discriminated tubulointerstitial injury in glomerular diseases with high specificity and sensitivity.