Does an Extra Kidney-Ureter-Bladder (KUB) Radiography Taken at Upright Position During Routine Intravenous Urography Provide Any Diagnostic Benefit?

Kamil Gurel, Safiye Gurel, Melike.E. Kalfaoglu, Cigdem Gkay

Abant Izzet Baysal University, Izzet Baysal School of Medicine, Department of RadiologyBolu/TURKEY

IntroductionIntravenous urography (IVU) has long been the main imaging evaluation of urinary tract disease.

However, the use of US, CT, and MRI has surpassed the use of IVU in the last two decades.

IntroductionThe declining use of IVU in clinical practice presents a challenge for instruction in urographic technique and interpretation. Nevertheless, IVU might still be important in the diagnosis of some urinary tract disease among other new modalities.

PurposeThe aim of this prospective study is to assess the value of taking a kidney-ureter-bladder (KUB) radiography at upright position during routine IVU in terms of diagnostic benefit.

Methods and MaterialsSeptember 2003-March 2006, 164 consecutive patients were referred for IVU exam

In our department, a basal standart IVU exam consists of totally 5 radiographies: Precontrast supine KUB Post-contrast supine KUB at 7th and 15th minutes Pelvic supine graphies for full bladder and post-voidingWhen needed, additional compression and/or oblique radiographies

Methods and MaterialsFor all patients, an additional post-contrast 15th min. upright KUB radiography was obtained Two reviewers analyzed the 15th min. upright KUB comparing to 15th min. supine KUB radiographies together, resulting in a consensus interpretation.

Methods and MaterialsThis study is approved by our institutional review board and informed consent was obtained from patients.

Methods and MaterialsStatistical Evaluation Evaluations were expressed in percentages.

Results164 patients 80 women, 84 men Mean age 44,5 15,4 years

Clinical Data:Urolithiasis. (n=95) Collecting system dilatation....... (n=21) Flank pain.. (n=10) Urinary tract infection.......... (n=10)Hematuria...(n=6)Renal Cyst..... (n=5)Control after ESWL ......... (n=3)Others (bladder ca,).. (n=14)Results

ResultsDiagnostic benefits of 15th min. upright KUB72 (43,9%) of 164 patients Nephroptosis (n= 40)Better filling of collecting system (n=9)Differentiation of pheloboliths from urolithiasis (n=10)Emptying of collecting sistem (n=51)Milk of calcium (n=2)

Results1.Nephroptosis (Asymptomatic) Downward displacement of kidney by more than two vertebral bodies or 5 cm

40 patients (24.3%) [bilateral (n=15), unilateral (n=25)]

SupineUpright 57 yo, F, Right renal cyst and minimal pelvicaliectasia on US

43yo, M, Right flank painSupineUpright

2. Better filling of collecting system 9 patients (5.4%) [ureteral filling (n= 8), upper pole infindibular filling (n=1) ]Results

24 yo, F, nephrolitiasisSupineUprightPre-contrast

SupineUpright

48yo, M, 48 yo, M, urinary tract infectionSupineUpright

Results3.Differentiation of pheloboliths from urolithiasis 10 patients (16.4%) (lower urinary tract)

SupineUpright 44 yo, M, ureterolithiasis suspicion

L ureterSupineUpright

Results4. Emptying of collecting sistem51 patients (31%)

10, yo, F, minimal pelvicaliectasia at right kidney on USSupineUpright

Results5. Milk of calcium 2 patients (1.2%)

DiscussionRecently IVU has almost been accepted as outdated.

On the other hand alternative modalities have their own limitations, and despite their increasing use, the ideal global urinary tract examination still remains controversial

*Dyer RB, et al. Intravenous Urography: Tecnique and Interpretation. Radiographics 2006; 1(4):800-821.discussion 822-824.

DiscussionNawfel RD, et al. Patient Radiation Dose at CT Urography and Conventional Urography. Radiology 2004; 232:126-132. The patient effective dose, therefore radiation risk for CT urography was 1.5 times greater than that for conventional urography

Radiation risk is increased for smaller patients in CT urography and for larger patients in IVU.

CT urography performed with multidetector row CT may eventually replace IVU. However, the increased radiation risk from this examination compared with IVU should be considered in the context of the amount of information that is necessary for the diagnostic task.

*Nawfel RD, et al. Patient Radiation Dose at CT Urography and Conventional Urography. Radiology 2004; 232:126-132.

Discussion Upright positioning seems to:Be possible-technically- only in IVUMay be a part of routine IVU Can supply data about verification of urine flow Can provide better fillingShow positional change in gravity-related layering, nephroptosis and phleboliths

DiscussionWeak points of this study are:There is no control grup (for comparison of total number of films and patient radiation dose) Absence of interobserver variability assessment

Conclusion: IVU, a cornerstone in urinary system imaging, has slowly been withdrawn from routine clinical practice in the era of CT or MR urography.

However, the capability of using gravitational forces by obtaining simply an upright radiography still provides some diagnostic benefits, in which CT or MR urography might easily miss.