- URINARY TRACT
There are many methods of imaging the urinary tract but plain abdominal X-ray and ultrasound scan are usually done first in most cases, especially in a third-world setting.
Methods of imaging:
- Plain films
- Intravenous urogram (pyelogram) – (IVU,IVP;excretion urography)
- Micturating cystogram or cystourethrogram (MCUG)
- Urethrogram (ascending urethrogram)
- Retrograde pyelogram
- Antegrade pyelogram
- Radionuclide studies:
- Computed tomography (CT)
- Magnetic Resonance Imaging (MRI)
Ultrasound should be performed before other investigations such as intravenous urography for the following reasons:
- it is cheap and readily available
- it is safe – no danger of contrast reactions
- no radiation
- the renal outlines are clearly seen
- no interference from bowel gas
- renal size can be easily assessed. Cortical loss can be measured.
- renal texture can be assessed e.g. echogenic in acute nephritis
- particularly good for renal failure, when IVP is contraindicated
- renal masses are seen, even if only small (earlier than on IVP)
- the bladder is well seen as is the bladder wall
- the prostate can be assessed
- residual urine can be measured fairly accurately
- other pelvis abnormalities may be visualised e.g. ovarian mass or fibroids
- the ureters cannot be seen unless dilated.
- calyceal detail cannot be seen which is necessary for assessment of chronic pyelonephritis, papillary necrosis
- uroendothelial (transitional cell) tumours of the renal pelvis/calyces are not visualised until large.
COMMON URINARY TRACT PROBLEMS:
- Renal angle pain- infection; calculi.
- Renal mass
- Obstruction of the urinary tract –
…………. Uretero-pelvic junction obstruction (UPJ)
…………..ureteric stone, sloughed papilla, ureteric stricture
…………. ureteric or bladder tumour,
…………..pelvic malignancy e.g. carcinoma cervix.
…………..retroperitoneal mass or fibrosis
- Renal trauma
- Trauma to the bladder and urethra e.g. pelvic fractures.
- Renal cysts
- Ureteric reflux
- Urethral stricture
- Posterior urethral valve
- Vesicovaginal fistula
- Renal, ureteric, bladder stones
- Schistosomiasis – ureteric strictures, bladder masses
- Congenital lesions: duplex systems, polycystic disease, absent or pelvic kidney
1. PLAIN FILMS:
Some information about the urinary tract may be obtained from plain films. Bladder distension, opaque calculi, and bladder wall calcification may be seen. Calcified fibroids, prostatic calcification and calcification of the seminal vesicles is readily seen. In the presence of severe pain, excess gas in the bowel limits the value of the plain film and calculi are usually shown more easily on ultrasound examination or intravenous urography.
Features which may be seen on plain film
- Calculus. Shown to be lying within the kidney by taking an oblique film, when it maintains a constant relationship to the kidney. Usually forms in a calyx and may be single or multiple. Often bilateral. Small fragments may break off passing down the ureter producing colic.
- Staghorn calculus – large calculus occupying much of the pelvi-calcyeal system.
- Nephrocalcinosis – multiple calcifications in the parenchyma, not the pelvicalyceal system, most commonly associated with:
… Renal tubular acidosis
… Medullary sponge kidneys
- Wall of ureter in schistosomiasis
- Wall in Schistosomiasis
- Calculus – may be small, large, laminated or just calcified around periphery
d) Fibroids, prostate, seminal vesicles
Mesenteric lymph nodes, pleboliths & calcified costal cartilages may also be seen and need to be distinguished from urinary tract calcification. Phleboliths are usually multiple and rounded with a central darker ring. Most are within the pelvis. Calcified nodes show uneven calcification and can lie anywhere within the abdomen. They change position and their relationship to other structures with a change in position of the patient.