Pelvi ureteric junction obstruction in hydronephrosis. Best diagnosis with

[Cl i.e. (Nuclear imaging): (1294-Bailey & Love 25th)Isotope renography (Diuretic nuclear renal scan) is the best test to establish that dilatation of the renal collecting system is caused by obstruction 99m Tc labelled DTPA or MAG-3 passage through the kidneys can be tracked using a gamma camera 99mTc DTPA is quickly clearedfrom a normal kidney but is trapped in the renal pelvis on the obstructed side and will not be washed out even if the flow of urine is increased by administering furosemide* USG - regularly used to diagnose PUJ obstruction in utero* Excretion urography is only helpful if there is significant function in the obstructed kidney* Retrograde pyelography is rarely indicated but will confirm the site of obstruction immediately before corrective surgeryCongenital PUJ obstruction* Cong PUJ obstruction is the most common cause of significant dilatation of the collecting system in the fetal kidney* More common in boys (2:1)* Usually unilateral but bilateral in 10-40%*** More common in left side** Associated anomaliesa. Renal dysplasiab. Multicystic dysplastic kidneyc. Renal agenesis**d. Vesico-ureteric refluxe. PUJ obstruction was noted in 21% of children with the VATER group of anomalies* Most common presentation of cong PUJ obstruction is asymptomatic* Whitaker test (pressure flow studies) can be used to find out obstruction to flow of urineIn whitaker test catheters are placed in renal pelvis and bladder. Fluid is infused in to the kidney and the pressures are measures. A differential pressure between kidney and bladder could then be indicative of obstruction to the flow* Anderson Hynes Dismembered Pyeloplasty is the most Commonly employed technique