Focal or isolated caliectasis of upper calyx kidney, ultrasound imaging

This patient has a dilation of the upper calyx alone. Solitary or focal caliectasis is due to stricture of the calyceal neck, usually due to infections such as Kochs. Ultrasound images below show solitary dilation of the upper calyx of right kidney. 

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kidney ultrasound imaging

The color Doppler ultrasound image above shows normal vascularity s/o no surrounding inflammation. 

Final diagnosis: isolated caliectasis upper calyx right kidney, due to Kochs 

D/d: stricture of calyx due to passage of renal calculus