* URINARY-USEFUL TIPS *

1*WHEN DIVIDED RENAL FUNCTION IS REQUIRED, ANTERIOR AND POSTERIOR VIEWS ARE ADEQUATE. HOWEVER, IF AREA OF CORTICAL SCARRING ARE TO BE IDENTIFIED, eg IN CHILDREN WITH RECURRENT URINARY TRACT INFECTION OR REFLUX, THEN OBLIQUE VIEWS ARE NECESSARY TO PROVIDE GOOD DEFINITION WITH CORTICAL OUTLINE*

2*APPROXIMATELY 60% OF INJECTED DMSA IS TAKEN UP BY THE KIDNEYS, BUT IT SHOULD BE REMEMBERED THAT 10-15% IS EXCRETED. IF THE BLADDER IS NOT EMPTIED BEFORE IMAGING AND IS INCLUDED IN THE FIELD OF VIEW, IT WILL BE CLEARLY VISUALIZED. HOWEVER, ON OCCASION, WHEN THE KIDNEY IS DAMAGED, THERE MAY BE INCREASED EXCRETION OF DMSA WITH BLADDER VISUALIZATION* *PERCENTAGE OF DIVIDED FUNCTION SHOULD BE CALCULATED FROM ANTERIOR AND POSTERIOR IMAGES USING THE GEOMETRIC MEAN*

3*SPECT IMAGING PERMITS THE VISUALIZATION OF SMALLER LESIONS AND SCARS BY VISUALIZING THE ENTIRE RENAL PARENCHYMA WITH NO OVERLYING TISSUE*

4*ALWAYS IMAGE ANTERIORLY AS WELL AS POSTERIORLY TO ASSES THE FUNCTION OF THE FUSED BRIDGE ADEQUATELY*

5*DOWNWARD DISPLACEMENT OF THE KIDNEY (NEPHROPTOSIS) MAY CAUSE SIGNIFICANT ERRORS OF QUANTITATION. PATIENTS SHOULD BE IMAGED IN THE SUPINE POSITION TO REDUCE THIS SOURCE OF ERROR*

6*IN SOME CASES OF RENAL TUBULAR DYSFUNCTION, SUCH AS RENAL TUBULAR ACIDOSIS, THERE MAY BE VERY POOR UPTAKE OF DMSA BY THE KIDNEYS WHICH MAY RESULT, ON RARE OCCASIONS, IN MISLEADING INFORMATION ABOUT RENAL FUNCTION*

7*THE IVU OFTEN GIVES UNRELIABLE INFORMATION ABOUT RENAL FUNCTION AND DISTRIBUTION OF FUNCTION WITHIN A KIDNEY*

8*WHEN A KIDNEY CONTRIBUTES LESS THAN 15% TO THE TOTAL RENAL FUNCTION, THERE WILL USUALLY BE NO IMPROVEMENT AFTER RELIEF OF OBSTRUCTION*
*RADIONUCLIDES ARE NOT USED TO INVESTIGATE THE SITE OR THE CAUSE OF OBSTRUCTION AND SHOULD NOT BE USED TO EXCLUDE OBSTRUCTION AS A CAUSE OF ACUTE RENAL FAILURE*

9*A FALL IN THE T/A CURVE BEFORE 20 MINUTES VIRTUALLY EXCLUDES OBSTRUCTION, BUT A RISING CURVE, WHILE SUGGESTIVE, DOSE NOT PROVE THE PRESENCE OF OBSTRUCTION*
*THE EFFECT OF GRAVITY IN CAUSING EMPTYING OF THE COLLECTING SYSTEMS EXCLUDES OBSTRUCTION, BUT FAILURE TO DO SO NOT CONFIRM THE PRESENCE OF OBSTRUCTION*
*THE COMBINATION OF FAILURE TO DRAIN FOLLOWING AMBULATION TOGETHER WITH FAILURE TO WASHOUT WITH DIURESIS CONFIRMS PUJ OBSTRUCTION*

10*ACCURATE MEASUREMENT OF RESIDUAL RENAL FUNCTION MAY BE DIFFICULT WHEN THERE IS A GROSSLY ENLARGED COLLECTING SYSTEM PRESENT. FUNCTION MUST BE MEASURED BEFORE FILLING OF THE SYSTEM OCCURS. FOR EXAMPLE, IF FUNCTION WAS MEASURED AT 20 MINUTES, IT WOULD BE GROSSLY OVERESTIMATED. HOWEVER, ON THE FUNCTIONAL IMAGE IT CAN, ON OCCASION, BE DIFFICULT TO DEFINE THE CORTICAL OUTLINE ACCURATELY AND ALSO TO SELECT APPROPRIATE SITES FOR BACKGROUND SUBTRACTION*

11*FUNCTIONAL STUDIES IN SUCH CASES PROVIDE THE NECESSARY CONFIRMATION FOR SURGICAL TREATMENT, AND ALSO PROVIDE A BASELINE FUNCTIONAL MEASUREMENT FOR SUBSEQUENT FOLLOW-UP TO ASSESS THE FUTURE GROWTH OF THE KIDNEY AND THE EFFECT OF SURGICAL INTERVENTION*
*WHEN THERE IS MARKEDLY DECREASED RENAL FUNCTION, AN IMPAIRED DIURETIC RESPONSE MAY BE OBTAINED; THUS FALSE POSITIVES FOR OBSTRUCTION CAN OCCUR IN THE PRESENCE OF DILATATION. A DOUBLING OF THE DOSE OF DIURETIC IS THEREFORE RECOMMENDED IN THIS SITUATION*

12*THE GFR IN INFANTS IS LOW, AND THE RESPONSE TO DIURETIC IS LESS COMPARED WITH OLDER CHILDREN, THEREFORE FALSE POSITIVES MAY OCCUR; THIS MUST BE TAKEN INTO ACCOUNT WHEN INVESTIGATING NEWBORN INFANTS. A STUDY SHOWING LACK OF OBSTRUCTION IS OF MORE SIGNIFICANCE THAN ONE SUCH AS THIS, SHOWING POSSIBLE OBSTRUCTION*

13*WITH DETERIORATING RENAL FUNCTION, THE DIAGNOSIS OF OBSTRUCTION USING DIURETIC RENOGRAPHY BECOMES INCREASINGLY UNRELIABLE*

14*IT IS IMPORTANT TO BE AWARE THAT WITH LOWER URINARY TRACT OBSTRUCTION THERE MAY BE WASHOUT FROM THE UPPER TRACT INTO A GROSSLY DILATED LOWER TRACT. THUS IF ONLY THE RENAL AREA IS MEASURED, FALSE NEGATIVE RESULTS FOR OBSTRUCTION MAY BE OBTAINED*

15*A POST-MICTURITION FILM MAY BE USEFUL TO EXCLUDE OBSTRUCTION AT THE LOWER END OF THE URETER AS A FULL BLADDER MAY OBSCURE THE OBSTRUCTED URETER*

16*OBSTRUCTION MAY BE INTERMITTENT*
*A PROMINENT PHOTON-DEFICIENT AREA IS FREQUENTLY SEEN ON INFANT STUDIES AND IS DUE TO MILK IN THE STOMACH AFTER A RECENT FEED, GIVEN TO ASSIST SEDATION*

17*FOLLOWING A PYELOPLASTY OPERATION, A DTPA STUDY MAY APPEAR TO SHOW PERSISTENT OBSTRUCTION. FOLLOWING DIURETIC AND DELAYED IMAGING, WASHOUT WILL BE OBSERVED IF THE OPERATION WAS SUCCESSFUL*

18*DMSA IS THE RADIOPHARMACEUTICAL OF CHOICE TO SHOW CORTICAL SCARRING*
*MULTIPLE VIEWS ARE NECESSARY TO SHOW SCARS OPTIMALLY*
*DMSA IS THE RADIOPHARMACEUTICAL OF CHOICE FOR ASSESSMENT OF DIVIDED FUNCTION*

19*DMSA ABNORMALITIES SEEN WITHIN 3 MONTHS OF AN ACUTE INFECTION MAY RESOLVE. A FOLLOW-UP STUDY SHOULD THEREFORE BE PERFORMED TO DIFFERENTIATE TRANSIENT CHANGE DUE TO PYELONEPHRITIS FROM PERSISTENT RENAL SCARRING*

20*REFLUX MOST COMMONLY OCCURS INTO THE LOWER MOIETY OF A DUPLEX KIDNEY.OBSTRUCTION MOST COMMONLY AFFECTS THE UPPER MOIETY*
*GENERALIZED RENAL CONTRACTION WITHOUT CLEAR-CUT SCARS MAY BE A CONSEQUENCE OF REFLUX*

21*DTPA WILL NOT DEMONSTRATE SCARS AS WELL AS DMSA*
*CALYCEAL DILATATION WITHOUT OBSTRUCTION IS A FEATURE OF PREVIOUS REFLUX*

22*SOME FEATURES OF REFLUX, INCLUDING SCARRING, DILATATION OF CALYCES AND VISUALIZATION OF THE URETER, MAY BE RESIDUAL EFFECTS OF PREVIOUS REFLUX, AND DO NOT INDICATE THAT REFLUX IS STILL OCCURRING*

23*ALL PHASES OF THE DTPA STUDY MAY PROVIDE INFORMATION ABOUT VEXICOURETERIC REFLUX*
*REFLUX IS NOT ALWAYS ASSOCIATED WITH SCARRING OR DAMAGED OF THE KIDNEY*

24*REFLUX INTO A KIDNEY CAN CAUSE CONFUSION AND MAY RESULT IN EITHER AN OVERESTIMATE OF FUNCTION IF THE MEASUREMENT IS MADE AFTER THE PARENCHYMAL PHASE, OR A MISDIAGNOSIS OF OBSTRUCTION*

25*IT IS ESSENTIAL TO OBTAIN DELAYED IMAGES OF THE ABDOMEN TO DETECT URINARY LEAKS*

26*RADIONUCLIDE STUDIES ARE PROBABLY THE INVESTIGATIONS OF CHOICE FOR RAPID ASSESSMENT OF UPPER ABDOMINAL TRAUMA*

27*IN THE PRESENCE OF RENAL FAILURE RADIONUCLIDE IMAGING CANNOT BE USED TO EXCLUDE OBSTRUCTION; THIS IS THE ROLE OF ULTRASOUND*

28*FOR THE EVALUATION OF ACUTE RENAL FAILURE IN CHILDREN A COMBINATION OF DTPA RENAL SCAN AND ULTRASOUND IS USUALLY SUFFICIENT AND AVOIDS THE RISKS ASSOCIATED WITH CONTRAST MEDIA*
*NOTE THAT THE RESOLUTION OF IMAGES IN CHILDREN IS OFTEN POOR IN COMPARISON WITH THOSE OBTAINED IN ADULTS*

29*THE DTPA SCAN PROVIDES A POSITIVES DIAGNOSIS OF ATN; MOST OTHER CAUSES OF ACUTE RENAL FAILURE WILL DIFFER, BUT THEY ARE INDIVIDUALLY INDISTINGUISHABLE FROM EACH OTHER*

30*RECOVERY TIME (FROM ATN) VARY FROM A FEW DAYS TO A FEW MONTHS*
*RETENTION OF TRACER IN THE KIDNEY FROM 2 MINUTES TO 30 MINUTES IS THE FIRST SIGN OF RECOVERY*

31*THE APPEARANCES OF A DYNAMIC RENAL SCAN ARE A GOOD GUIDE TO PROGNOSIS IN ACUTE VASCULAR DISEASE, BUT MAY BE MISLEADING IN OTHER CONDITIONS, MOST NOTABLY HAEMOLYTIC URAEMIC SYNDROME IN CHILDREN, WHEN THERE MAY BE VIRTUALLY ABSENT BLOOD FLOW WITH SUBSEQUENT COMPLETE RECOVERY*

32*DTPA SCANS WILL ONLY RARELY CONTRIBUTE TO THE MANAGEMENT OF PATIENTS WITH CONTRACTED KIDNEYS WHO ARE IN CHRONIC RENAL FAILURE*
*A DTPA STUDY CANNOT EXCLUDE THE PRESENCE OF OBSTRUCTION IN SUCH CASES*

33*MAG3 IS THE AGENT OF CHOICE IN PATIENTS WITH RENAL FAILURE, SINCE THE BETTER RENAL EXTRACTION IMPROVES VISUALIZATION*

34*PSEUDOTUMOURS ARE CAPABLE OF ACCUMULATING AND EXCRETING RADIOPHARMACEUTICALS UNLIKE TRUE TUMOURS*

35*INVESTIGATING A PSEUDOTUMOURS:
-MULTIPLE VIEWS USING DMSA ARE NECESSARY
-CAREFUL CORRELATION WITH IVU OR ULTRASOUND IS ESSENTIAL*

36*THE EARLY 30 SECOND IMAGES OF THE DMSA SCAN CAN BE USED TO ASSESS RENAL PERFUSION OF A LESION*

37*A DUPLEX SYSTEM IS SUSPECTED IF THERE IS SCAN EVIDENCE OF :
a. ELONGATED KIDNEY
b. LATERAL MID-ZONE IMPRESSION
c. UNUSUAL POSITION OF COLLECTING SYSTEM*

*THE REDUPLICATED URETERS FROM A DUPLEX KIDNEY MAY:
a. JOIN SOON AFTER LEAVING THE UPPER OR LOWER MOIETY
b. JOIN ANYWHERE BETWEEN THE KIDNEY AND THE BLADDER
c. ENTER THE BLADDER SEPARATELY*
*A DUPLEX SYSTEM IS ASSOCIATED WITH REFLUX, WHICH OCCURS MOST OFTEN IN THE LOWER MOIETY*
*THE UPPER MOIETY MAY BECOME OBSTRUCTED*

38*IF AN ECTOPIC KIDNEY IS SUSPECTED, OR ONLY ONE KIDNEY IS SEEN ON THE POSTERIOR VIEW, ALWAYS OBTAIN ANTERIOR VIEWS WHICH INCLUDE THE PELVIC KIDNEY*
*IF NECESSARY, RE-IMAGE AFTER MICTURITION*

39*A PELVIC KIDNEY MAY BE CONFUSED WITH BLADDER ACTIVITY IN A NEONATE*

40*MAG3 OR HIPPURAN, BECAUSE OF THEIR CLOSER DEPENDENCE ON RENAL PLASMA FLOW, ARE MORE SENSITIVE THAN DTPA FOR DETECTING IMPAIRED RENAL BLOOD FLOW. QUANTITATION OF UPTAKE, RETENTION AND TRANSIT TIMES WILL ADD INFORMATION TO THE VISUAL INSPECTION OF IMAGES*

41*DMSA IS VERY SENSITIVE FOR SEGMENTAL RAS*
*DMSA AND HIPPURAN TOGETHER MAY PROVIDE THE BEST EVALUATION OF SUSPECTED RENAL HYPERTENSION*
*DMSA AND HIPPURAN SCANS CAN BE PERFORMED ON THE SAME HOSPITAL VISIT*

42*RADIONUCLIDE INVESTIGATIONS DEPEND ON ASYMMETRY, AND THEREFORE SYMMETRICAL RAS MAY BE MISSED, BUT PROLONGED TRANSIT TIMES MAY BE MEASURABLE*
*WHEN RAS IS CRITICAL, CONTRAST AGENTS FOR X-RAY PROCEDURES MAY CAUSE RENAL FAILURE*

43*NUCLEAR MEDICINE STUDIES ARE NOT DIAGNOSTIC OF AN ANEURYSM ONLY THE LUMEN IS IDENTIFIED*
*ALL PATIENTS SHOULD HAVE A RENAL BLOOD FLOW STUDY PREOPERATIVELY AS A BASELINE*

44*FUNCTIONAL FOLLOW-UP WITH TRACERS IS THE OPTIMAL METHODS FOR INVESTIGATING THE EFFECT OF ANGIOPLASTY, ie THE EFFECT OF THE STENOSES IS MORE IMPORTANT THAN THE APPEARANCE*

45*ON THE DTPA SCAN ALONE REJECTION AND CYCLOSPORIN TOXICITY ARE INDISTINGUISHABLE; BOTH MAY CAUSE DECREASED PERFUSION AND DECREASED GFR*

46*PROGRESSIVE RENAL SCARRING IS FREQUENTLY SEEN IN A CHRONIC DETERIORATING TRANSPLANT*

47*ATN IS COMMON FINDING POSTOPERATIVELY WITH NON-RELATED DONOR KIDNEYS. THE VALUE OF THE DTPA SCAN IS IN MONITORING THE BLOOD FLOW UNTIL FUNCTION RETURNS, WHICH MAY TAKE SEVERAL WEEKS*

48*AVASCULAR GRAFT MAY BE DUE TO:
-ARTERIAL THROMBOSIS
-END STAGE REJECTION
-HYPERACUTE REJECTION
-VENOUS OCCLUSION
THESE ARE INDISTINGUISHABLE ON THE SCAN*

49*A FUNCTIONING TRANSPLANT IS NECESSARY TO DETECT A LEAK*
*DELAYED VIEWS AND VIEWS AFTER MICTURITION MAY BE NECESSARY TO DETECT THE LEAK*
*LEAKS ARE USUALLY, BUT NOT ALWAYS, PAINFUL*

50*ALTHOUGH PELVIC URETERIC DILATATION IS SEEN IN ASSOCIATION WITH OBSTRUCTION, THE COMMONEST CAUSE OF A DILATED COLLECTING SYSTEM IS VESICOURETERIC REFLUX*

51*FAILURE OF RECOVERY OF FUNCTION FROM ATN SHOULD BE INVESTIGATED WITH ULTRASOUND TO EXCLUDE OBSTRUCTION*

*URINARY IMAGING INTERPRETATION*
*URINARY CLINICAL APPLICATIONS*
* URINARY SYSTEM *