Duplex Doppler US of the kidney: differentiation of obstructive from nonobstructive dilatation.

Abstract

Distinction of the obstructed from the nonobstructed dilated renal collecting system is a difficult problem often requiring interventional procedures and pressure measurements. The authors prospectively performed duplex Doppler ultrasound (US) evaluations in 21 kidneys (obstructed, n = 14; nonobstructed, n = 7) immediately before percutaneous nephrostomy. In addition, ten of the obstructed kidneys were evaluated with follow-up Doppler US after percutaneous nephrostomy. Renal obstruction caused a change in the Doppler waveform detected by means of the resistive index (RI). Thirteen of the 14 obstructed kidneys had a RI value greater than .70, while none of the nonobstructed kidneys had a RI value exceeding .70. Relief of the obstruction resulted in a reduced RI; in nine of ten kidneys, the RI was less than or equal to .70 (similar to that of the nonobstructed kidneys). When a dilated collecting system is being imaged, additional evaluation with duplex Doppler US may help distinguish obstructed from nonobstructed dilatation, which may be of particular benefit in patients with conditions that usually predispose them to collecting system dilatation.

Diuretic Doppler ultrasonography in chronic unilateral partial ureteric obstruction in dogs

“…Previous studies showed that the RI of hydronephrotic obstructed kidneys is significantly higher than that in kidneys with unobstructive pelvicalyceal dilatation [1]. A high intrarenal RI in obstructed kidneys is mainly a result of the decrease in diastolic renal blood flow velocity.…”

“…A high intrarenal RI in obstructed kidneys is mainly a result of the decrease in diastolic renal blood flow velocity. Platt et al [1] reported that the RI in normal adult humans is f0.7; using this value, Doppler US has clinically excellent sensitivity and specificity in determining the presence or absence of obstruction in patients with calyceal dilatation. However, there are cases of mild ureteric obstruction with an intrarenal RI of f0.70 [2] and the present UPUO dog model closely represents such chronic mild unilateral ureteric obstruction in humans.…”

“…A reduction in diastolic flow relative to systolic flow occurs in hydronephrotic kidneys, and this reduction is reflected in an increased intrarenal RI. In normal individuals the intrarenal RI is f0.70 [1] but there are many patients with mild but functionally significant hydronephrosis in whom the intrarenal RI is <0.70 [2]. To enhance the diagnostic accuracy of the RI in these Accepted for publication 2 April 2002 patients, the diuretic intrarenal RI measurement (diuretic Doppler US) has recently been introduced [3][4][5][6].…”

Mean resistive index as a prognostic tool for hydronephrosis in patients with acute renal colic: a study in a tertiary care

“…A better and direct functional evidence of the obstruction is obtained by the more recent Doppler US techniques to gather more information on the level of obstruction. 14,15 The response of the renal blood flow to the site of urinary obstruction is said to be phasic. [16][17][18][19] At the onset of the obstruction, there is an immediate increase in the renal pelvic pressure, which results in the vasodilatation caused by the vasoconstrictor factors.…”

Sickle cell disease: chest and abdominal manifestation-A CT based study

“…Also, there is a possible bacterial infection of the scarred renal tissues and functional tubule abnormalities in conjunction with the compromised immunity, leading to abscess formation [26,27] Table(3) presented the lungs CT manifestation in SCA : pleural effusion, pneumonia ,atelectasis, ground glass nodules ,consolidation ,fibrosis lung abscess which was found in different ages as well; at all types of SCD including Hb SS ,Hb SC ,Hb SB 0-thalassemia ,Hb SB+ thalassemia that are presented in table ( 8) Similar studies have mentioned that the acute chest syndrome is one of the most common causes of hospitalization and even death of SCA patients, pulmonary vascular obstruction. [28]and pleural effusion may also be seen, [29,30] Patients with SCA may develop obstructive or restrictive lung diseases, when there is a progressive decline in the pulmonary functions .This may be explained by established fibrotic lung changes from repeated episodes of pulmonary infective and vaso-occlusive events. High resolution CT scan (HRCT) shows these interstitial changes, that are of reticular or reticulonodular pattern and may be associated with traction bronchiectasis [31] …”