Functional Renal Scintigraphy

Differentiate a dilated renal collecting system from an obstructed renal collecting system

Furosemide is a loop diuretic that acts on the kidneys to increase water loss from the body; an anthranilic acid derivative. By increasing urine flow, a functional obstruction can be overcome by increasing pressure in the renal pelvis and thus allowing urine flow from the collecting system into the ureter to the bladder. This allows the documentation of the diuretic urodynamic and differentiation of a fixed anatomic from functional abnormality.

20-40mg in adaults.5-1mg/kg in pediatric patientsIt is injected over 1-2min.1-2min or 2-5min effects are visible

If the tracer in the renal pelvis or calyces at the conclusion of renal function imaging, the administration of a diuretic to rule out urinary tract obstruction is given

Using 10mCi of Tc-MAG3 is the best optionTc99m-DTPA can also be used

Tc99m-DMSA and glucoheptonate

Used to document global and regional changes in renal function;In patients with acute pyelonepritis, areas of decreased frunction may improved with treatment. In children with vesicoureteral reflux (VUR) and a history of urinary tract infections (UTIs). Detect the presence or absence of small renal infarction. Sometimes it is used to differentiate a prominent column of Berlin seen in ultrasound; The detection of hypertrophied columns of Berlin is important because it alleviate biopsy and radical surgeries.

Evaluate edema or scarring from acute pyelonephrotitisConfirmation of suspected hypertrophied column or berlin

Taken up by renal cortex90% bound to plasma proteins which prevents significant glomerular filtrationThe DMSA molecules splits upon reaching the kidneys16% of DMSA will be in the urine 3hrs after injection

DMSAAdults: 5mCi-10mCiChildren: 50uCi

secreted by glomerular filtration and tubular secretionpermits visualization of renal blood flow and imaging of renal cortexrenal clearance is about 50% at 3hrs

Adult: 10-15mCiChildren: 200uCi

Pregnancy

20% window with an energy of 140KeVStatic images are taken 2hrs after rph administration500000 total cts for each images for a total of 5 imagesViews: POST/RAO/LAO/RPO/LPO of the kidneysUsed low field of view with parallel hole collimators for differential calculationsUsed pin hole collimator for cortical images

normal: smooth renal contour; symmetrical distribution of rph in each kidney and equal concentration in renal cortexAbnormal: Acute pyelonephritis appears as single or multiple defects resulting in decrease uptake. In differentiating the column of Berlin from a actual mass, the DMSA scan will demonstrate uptake in the column of Berlin but not in a mass caused by a tumor.

The two most commonly used are Captopril (Capoten) and Enalaprilat (Vasotec IV)

Captopril side effects include hypotension, dizziness, tachycardia, chest pain, rash, and loss of taste.Adverse side effects of enalaprilat include orthostatic hypotension, dizziness, chest pain, headache, dry cough, electrolyte disturbances, fatigue, abdominal pain, vomiting and diarrhea

Captopril: 25-50mg orally dissolve in 150-200ml water to enhance absorptionEnalaprilat: 40ug/kg in 10ml of normal saline; slow intravenous push over 3-5min to avoid any reaction.

Radiopharmaceutical is administered 60 min after ACE inhibitor

48hrs for captopril and a week for enalaprilat before study

It indicates that the hypertension is renin dependant, most likely produced by RAS, and it can be improved by renovascularization

Used for the evaluation of children with suspected vesicouretal reflux; It is the initial investigation of choice in selected children with urinary tract infections.

Tc99m pertechnetate, DTPA or Sulfur Colloid can be usedDose range: .5-1mCi

By catherizing the patient and directly instilling the radionuclide into the bladder or by injecting the patient with the tracer as it is excreted by the kidneys.Direct catheteriziation has a higher sensitivity and specificity than the indirect method and is the preferred method for radionuclide cystography.

Compartmental with flow of urine

sitting/supine with kidneys and bladder in FOV

No visible reflux and all of solutionis voided from bladder

Activity seen in the upper urinary tract during filling, full capacity and while voiding

Bladder (18mrads/mCi)