Diagnostic yield of intravenous urography in a Tertiary Care Hospital.
Background: Intravenous urography is the second most common tool after sonography for investigating urological pathology.
Objectives: To compare the effect of various factors like age, gender, symptoms and their duration on the yield of intravenous urography used for investigating uropathology.
Study type, settings and duration: Retrospective case review study was done at department of Radiology, Pakistan
Institute of Medical Sciences, Islamabad, from July - August 2009.
Materials and Methods: Over a period of 2 months, case records of all patients referred to the radiology department for intravenous urography were retrospectively analysed for their indications for referral and the findings of the urogram and variations in the pelvi-calyceal system. Demographic and clinical data for each patient was collected on prescribed proforma. All patients were prepared with low fat diet for 2 days to reduce bowel gases after which a preliminary post micturation control x-ray film was taken which included kidney and urinary bladder. Intravenous water soluble contrast was administered to all patients at a dose of 50 ml of 350-370 strength after which a series of cross kidney films were taken at 0, 5, 15 minutes with full bladder and post micturation films. These timings were modified in some patients with particular circumstances for optimal visualization, and to reduce the radiation dose.
Ultrasonography of the kidneys and urinary bladder was also performed in some patients when required and to verify results.
Results: Out of 127 patients studied, 93(74%) demonstrated pathology, while 33(26%) did not show any pathology and were thus labeled as normal. Most patients (42) were in the age group 32-39 years and the overall male to female ratio was 2:1 and it remained the same in all 4 age groups from 20-29 to 50-59 years. Calculus disease (stone) was the most common uropathology seen in 82(64.5%) patients. The shorter was the duration of presenting complaints the lesser were the chances of picking pathology on urogram as seen in 43% patients who had few week's complaints and showed a normal urogram. Those having complaints of over a month's duration showed 26% as normal cases and this figure dropped to 20% when presenting complaints were chronic i.e of few year's duration.
Conclusions: Use of intravenous urography should not be generalized to all cases. In younger patients with shorter duration of symptoms, ultrasonography should be performed as the first investigation. This non invasive technique will rule out many normal cases. Duration of symptoms should also be taken into account as patients with long standing symptoms are more likely to demonstrate pathology on intravenous urography.
Policy message: Initial intravenous urography facility should be available in all diagnostic centers of tertiary care hospitals.
Key words: Intravenous urography, ultrasonography, calculus.
Intravenous urography is considered as a gold standard for evaluating the urinary tract pathology1. Urinary tract dilatation has a variety of causes but the most common in the adult group are calculus obstruction, tumor in the urinary system and extrinsic compression and inflammatory disease2. Intravenous urography requires ionizing radiation, injection of contrast medium and normal functioning kidneys. It includes a control film of the abdomen including kidneys and urinary bladder referred to as a kidney and urinary bladder film and post contrast film. Visualization of the contrast medium in kidneys is divided into nephrographic and pyelographic phases. Nephrogram comprises of a cortical phase, due to vascular filling and a tubular phase, due to contrast in the tubules. Contrast in the calyceal system is the pyelogram, which depends not only on the distension of the pelvi- calyceal system but also on the concentration of the contrast medium within it.
Plain films help to differentiate between phleboliths and calculi by showing a radiolucent centre in 66% cases. Only 60% of ureteric calculi are visible on plain radiographs. As with excretory urography and ultrasonography, plain radiographs are unable to reveal other causes of flank pain3,4.
Disadvantages of intravenous urography include risk of minor and severe contrast medium reactions5, inability to diagnose the cause of flank pain unrelated to ureteric obstruction and prolonged examination is required to get a positive test.
This study was done to evaluate the yield of intravenous urography in patients presenting with different indications of urinary diseases.
Materials and Methods
This was a retrospective study. The case records of all consecutive patients, who underwent intravenous urography from July to August 2009, were retrieved and reviewed. The intravenous urography was performed for various indications like flank pain, haematuria, calculi requiring surgical intervention or stone retrieval at the department of diagnostic radiology, Pakistan Institute of Medical Sciences, Islamabad. The demographic and clinical data was collected on a prescribed proforma. All patients were first prepared with low fat diet for 2 days to reduce bowel gases after which a preliminary post micturation control kidney and urinary bladder film was taken. Intravenous water soluble contrast was administered to the patients at a dose of 50 ml of 350-370 strength, after which a series of cross kidney films were taken at 0, 5, 15 minutes with full bladder and post micturation films (1).
In some patients, this classical series was modified for optimum visualization, and to reduce radiation dose. The kidney size was measured according to the age6. For children who were greater than 1 year age the kidney size of 6.79+0.22 cms x age (years) was taken as normal. For adults the right kidney measurement was
10.74+-1.35 cms (SD) and for left kidney it was 11.10+-1.15 cms (SD).
Ultrasonography of the kidneys and urinary bladder was also done in some patients, where indicated.
Of 127 patients studied, 80 were males and 47 females with M:F ratio of 2:1. Most (98) patients were evaluated for flank pain followed by non specific abdominal pain (8). Eleven others were suffering from complaints i.e. backache, burning micturation, pain in right iliac fossa, radio-opaque shadows, difficulty in micturation and anuria. Five patients presented with history of pyelolithotomy, 2 cases each had complaints of haematuria and feeling of something coming out of vagina and 1 patient had surgical trauma. These patients were advised to undergo intravenous urography by their concerned departments while the department of Radiology only carried out the investigation. Duration of symptoms was also noted. Twenty two patients had complaints lasting since few days to weeks, 42 had complaints of few month's whereas 63 cases had symptoms since years. Intravenous urography findings were also noted at different phases of intravenous urography, kidney and urinary bladder and cystogram.
Kidney and urinary bladder radiographs showed radio opaque shadows in 65 films while 62 films showed no radio opaque shadows and were declared normal by the radiologist.
Nephrograms showed the size of the kidneys which in 42 cases showed right kidneys enlarged with sizes ranging from 13.5-14.5 cms with one grossly enlarged kidney (16.5cm). Twenty one left kidneys were enlarged while 2 were small (6.5cm and 8cm respectively). Rest of the kidneys were normal sized
Pyelograms were normal in 206 kidneys (105 left and 101 right). Moderate and mild to moderate hydronephrosis was reported in 21 and 16 kidneys on left and right side respectively.
In 7 kidneys, no pyelogram was obtained while delayed pyelogram was seen in 3 in one patient; the left kidney demonstrated a dense pyelogram.
Hypertrophic left kidney
For calyceal anatomy major calyces were counted in every renal unit. Three major calyces were seen in 219 kidneys (including 106 on right and 113 on left side). Four, five and six major calyces were also seen. Twenty four kidneys had four major calyces and two each had five and six calyces. Fifteen cases having four calyces were on the right side while, rest of extra calyces pattern was on left side. The pathology seen in the major calyces is shown in Table-1.
Some pathology was seen in 75 kidneys (44 right and 31 left) while rest of the kidneys were normal. Pathology ranged from blunting of the calyces to mild to moderate hydronephrosis, distortion and duplex systems. Obstructed calyces and delay in contrast opacification were also reported.
Table 1: Spectrum of pathology in major calyces.
Pathology###Number of patients
###Left kidney Right Kidney
Moderate Hydronepbrosis (HDN)###23###15
Mild to moderate HDN###4###-
Minor calyceal anatomy of the kidneys was also studied (Table-2).
Anatomy of the renal pelvis revealed normal findings in 182 renal units and the rest of the units had pathological features as shown in Table-3. The major pathology was hydronephrosis. Moderate hydronephrosis was seen in 35 renal units and mild to moderate hydronephrosis in 8 renal units making this the most common pathology in most patients.
Table 2: Pathology in the minor calyces.
Pathology###Number of patients
###Lefi kidney###Right kidney
Mild to moderate HDN###15###2
Table 3: Renal pelvis pathology.
Pathology###Number of patients
###Lefi kidney###Right kidney
Mild to moderate HDN###7###1
Ureters were normal in 202 renal units, (103 ureters on left side and 99 on right side). Fifty two ureters had abnormal features with hydronephrosis as the most common pathology seen in 20 ureters (12 left and 8 right). Non opacification was seen in 14 ureters (8 left and 6 right). Other pathologies included filling defects, duplex ureters and delayed opacification.
Cystogram was normal in 120 intravenous urography while 7 had pathologies including 4 as displaced downwards, and one each was trabeculated, small capacity, and pear shaped.
Thirty three urograms showed normal outline of the urinary system while, 94 were abnormal due to calculi, cystocele, ureterocele, pelvi ureteric junction obstruction, pelvic mass and perinephric abscess. One phlebolith and two cases of calcified mesenteric lymph nodes were also observed. Maximum numbers of patients were suffering from calculi disease (Table-4).
Table 4: Pathologic spectrum on intravenous urography.
Pathology###Number of patients
###Left kidney Right kidney
Non functioning kidney / small kidney###4###4
Uretero pelvic junction obstruction###-###2
Radiolucent stones were reported in 8 patients with 5 renal calculi and 4 ureteric calculi including 1 case each of perinephric mass, tuberculosis of urinary bladder, ureterocele, cystocele, abdominal mass involving both renal units, and a case of intra-pelvic mass causing distortion of calyceal system. Suspicion of stone passage was also suspected in 2 cases. Out of 127 patients, 94(74%) patients had pathology on intravenous urography examination and 33(26%) were normal.
Normal study was reported in 30 patients and all of them had normal kidney and urinary bladder radiograph. Sixteen patients had flank pain in the left and 10 had in the right flank while 3 patients had pain in both flanks. Two patients each complained of pain in the hypogastrium and abdomen and one patient each complained of haematuria and pain right iliac fossa, vomiting and loose motions. Impact of the chronicity of symptoms was also evaluated. The shorter was theduration of presenting complaints the lesser were the chances of picking pathology on urogram as seen in 43% patients who had symptoms for few week's duration and their urogram was normal. About 26% of those having complaints of over a month's duration had normal studies and this figure dropped to 20% when presenting complaints were chronic i.e of few year's duration. Ninteen came from Islamabad and Rawalpindi while the rest came from Peshawar, Chakwal and AJK.
This study shows that intravenous urogram is still the investigation of choice in cases of urinary problems like flank pain, obstructive uropathy, and stone disease. The diagnostic yield of this investigation was 76.4%, which is comparable with other studies7,8. Although ultrasound is a non invasive modality and does rule out renal pathology, some pathologies especially those in the mid and distal ureter may be missed due to over shadowing of the distal ureter by bowel gases. In contrast, pyelographic phase of intravenous urography clearly delineates the ureters in its entire length and identifies its pathology. Differentiation between calculi and phleboliths on plain x ray films often poses difficulty but this can be verified on intravenous urography studies where calculi fall in line of the renal system whereas phleboliths fall outside the line of kidney and urinary bladder.
In addition, intravenous urography also demonstrates the functional status of the renal system to some extent in its ability to concentrate contrast and opacify the renal system. It was seen that chronicity of symptoms also has its impact on the diagnostic yield as seen in this study where all those patients who had chronic complaints of a year's duration had some positive finding on intravenous urography. Similar findings were reported by others2,9,10.
We wish to thank Dr Saliha Habib for acquiring original images.
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2. Chen MY, Zagoria RJ, Dyer RB. Radiologic findings in acute urinary tract obstruction. J Emerg Med1997; 15: 339- 43.
3. Smith RC, Coll DM. Helical tomography in the diagnosis of ureteric colic. BUJ Int 2000; 86: 33-41.
4. Levine JA, Neitlich J, Verga M, Dalrymple N, Smith R C. Ureteric calculi in patients with flank pain: Correlation of plain radiography with unenhanced helical CT. Radiology 1997; 204: 27-31.
5. Chapman S, Nakienly R. A guide to radiological procedures. 5th ed. Edinburgh: Saunders Elsevier 2009.
6. Dahnert W. Radiology review manual.6th ed. Philadelphia: Lippincott Williams and Wilkins; 2007.
7. Deyoe LA, Cronan JJ, Breslaw BH, Ridlew M S. New techniques of ultrasound and colour Doppler in the prospective evaluation of acute renal obstruction. J Urol 1992; 148:1072-5.
8. Thukral A, Bhargava SK, Thukral AA. Diagnostic significance of excretory urography and ultrasonography in renal diseases. J Indian Med Assoc 1997; 95:579- 81.
9. Little MA, Johnson DS, Callaghan JP, Walshe JJ. The diagnostic yield of intravenous urography. Nephrol Dial Transplant. 2000; 15: 200-4.
10. Teh HS, Lin MBK, Khoo TK. Flank Pain: Is intravenous urography necessary? Singapore Med J 2001; 42: 425-7.
Corresponding Author: Mujahid Raza, Department of Radiology, Pakistan Institute of Medical Sciences, Islamabad.
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|Publication:||Pakistan Journal of Medical Research|
|Date:||Sep 30, 2011|
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