IVU Flashcards
what is the preferred method to image the urinary tract
used to be IVU however alternative imaging methods have superseded it with US offering a significant contribution but CTU is being used more often int he assessment of patients with renal colic with IVU as a suitable alternative
what does IVU stand for
intravenous urography
what does CTU stand for
computed tomography urography
what is urography
x-ray technique used for imaging the renal pelvis and urinary tract by the introduction of a radiopaque fluid
what does KUB stand for
kidneys, ureters, bladder
what does the IVU examination exam demonstrate
the anatomy of the urinary system (details of the renal cortex, calyceal size and shape, renal pelvis, pyelo-ureteric junction (PUJ), ureteric drainage and the bladder)
its function
Describe the process of an IVU of KUBs
iodinated contrast media is administered intravenously via the medial cubital vein and a series of images of the urinary system are taken at certain time intervals to demonstrate the anatomy and the function of the system as the contrast is excreted by the kidneys
what are the projections of an IVU of KUBs
what projections are occasionally taken of an IVU of KUBs
and why
why do CTU for KUBs
full length KUB (control image)
cross-renal (collimated to kidneys and upper ureters)
AP bladder
prone KUB
oblique single kidney
oblique bladder projections
to visualise the anatomy in a different plane
additional information may be gathered from scan images
what are the advantages of IVU
readily available (particularly in and emergency)
cost (relatively cheap in comparison)
demonstration of the anatomy of the renal system
demonstration of the function of the renal system
short waiting list
what are the disadvantages of IVU
radiation dose to the patient
use of iodinated contrast media (possible allergic reactions)
exam time (can be long if ‘delayed’ system)
cannot distinguish between different tumours
what are the clinical indications for IVU - 11 points
varying degrees of pain or discomfort - general feeling of unwell
severe single-sided loin pain renal colic (?renal calculi) pyrexia (with associated nausea/vomiting) dysuria nocturia haematuria cystitis (recurring) frequency of micturation poor stream of urine, cloudy or foul smelling passing clots recurring UTIs
some patients present with little/no symptoms but have other clinical indications such as … - 3 points
microscopic haematuria
incidental finding of calculi during other investigations
raised calcium levels
what are the contraindications for IVU - 5 points
use iodinated contrast media (can have side effects for patients with known allergies or known renal failure/disease) known allergy pregnancy (ionising radiation) raised urea levels diabetes
how can the patient preparation for IVUs vary?
individual protocols depend on the clinical indication for the exam - may include laxatives (to clear bowel) or the use of dietary control (for reduction of bowel gas patterns) in order to visualise the urinary system - not possible in acute settings
what is the standard patient preparation for an IVU - 7 points
individual protocol for bowel prep
ID check
pt in gown with removal of artefacts
LMP check
explanation of procedure with allergy check
necessary checks of the iodinated contrast media
empty bladder (so urine doesn’t dilute the contrast medium and bc pt in room for a while
why should the patients history/notes be checked before the exam - 7 points
if a previous US then ?findings
previous AXR within last 24 hours - use as control scan to reduce pt dose
previous contrast exams - ?allergic reaction
ensure emergency drugs at hand - trolley ?restocked/?checked
LMP
check exam form - ?justified
contrast media checks - correct media, iodine concentration, expiry date, batch, temperature, seal, state, etc.
what are minor reactions to the contrast media?
what is done in this situation?
localised pain at injection site
nausea and/or vomiting
heat sensation
urticaria
no need for medical intervention unless symptoms persist
what are major reactions to the contrast media?
what is done in this situation?
bronchospasm hypotension cardiac arrhythmias pulmonary oedema bradycardia cardiac arrest
no need to hesitate - medical assistance immediately
what is an IVU series
what are the possible projections included? - 5 points
varies drastically from site to site and between radiologists/urologists in the same site
control KUB/cross-kidneys cross kidney - timing varies from immediate to 10mins after injection full length optional full bladder (coned view) post-micturation bladder (coned view)
why is a control KUB image taken - 5 points
gives a preview of the area before injection
familiarity with specific anatomical position
familiarity with exposers prior injection
demonstration pathology & previous surgery
demonstration of pre-existing renal stones and their potential to effect urinary flow through the renal system
what happens if renal calculi is suspected on a control KUB image
when won’t calculi move and why
abdomen may be imaged again on the opposite stage or respiration, if the calculi is present in a different position on the 2nd image this proves it is calculi because abdominal structures change position
however, calculi within the peritoneal cavity won’t move as they are not affected by movement of the diaphragm
describe the use of a compression device
who should not have compression - 4 points
may be applied 5-10 mins after injection to restrict the flow of contrast to the kidneys if the calyceal system is not well demonstrated on the KUB/control - allows better visualisation of the kidney as contrast accumulates momentarily in the collecting systems
children, AAA, trauma, recent pain
why full bladder?
needs to be sufficiently full to demonstrate peripheral lesions within the pelvic cavity which may otherwise have been missed
why post-micturation?
demonstrates the emptying capacity of the patient and shows residual volume of urine remaining in the bladder
radiation protection - 6 points
ID check
careful technique to avoid repeats
efficient collimation
application of the 28 day rule where appropriate
use of alternative imaging modalities
apply gonad protection where applicable - on females obscures AOI on KUB but always for renal projections
care of the patient - 8 points
IV access should remain in place throughout the procedure (emergency drugs or additional contrast)
constant monitoring of the patient is essential - reduced LOC etc.
constant communication with the patient is essential
reassurance if it is a long procedure
removal of IV access (ASAP after exam)
allow patient to dress in private
give patient all follow up information once dressed
clean room and equipment and dispose of the equipment appropriately - infection control
common pathologies - 7 points
calculi benign prostatic hyperplasia/hypertrophy (BPH) carcinoma duplex system ectopic kidney horseshoe kidney reflux and pyelonephritis
what are possible causes of filling defects - 3 points
calculi
tumour
blood clot
describe calculi
why do they appear on radiographs
form when salts in the urine solidify into insoluble clumps which is small enough can pass undetected though urinary system via the urethra - larger calculi are likely to lodge in the ureter and may cause pain (renal colic) and possibly haematuria - the peristaltic action of the urethra exacerbates pain
can be radiopaque or radiolucent but show up due to attenuation properties - non-contrast identify radiopaque and radiolucent stones seen when contrast is introduced
what are the 3 main tumour types in the kidney
nephroblastoma (Wilm’s tumour) - paeds
renal cell adenocarcinoma
transitional cell carcinoma
describe renal obstruction
one kidney will show the cortex fill with contrast as its unable to drain through the normal filtration/drainage pathway towards the ureters - total obstruction
describe partial obstruction
bladder filling so contrast is getting from kidney to bladder but contrast remains in ureter and pelvi-calyceal system suggesting an obstruction is preventing the right ureter from draining normally - renal calyces appear ‘blunted’ or enlarged from the contrast concentration - hydronephrosis
what are staghorn calculi
large radio-opaque calculi occupying the space within the pelvi-calcyeal system, filling it in almost exactly the same shape as the system mimicking it as it was filled with contrast - incidental finding on KUB
describe horseshoe kidney
rare variant where the kidneys are joined at their upper or lower poles (usually lower) during embryonic function, each kidney will have its own ureter and contrast images will show calyces similar to a normal kidney - can be asymptomatic (incidental finding) but also linked to ongoing drainage problems and recurrent infections due to ‘back tracking’ of urine
describe a duplex system
a duplication of part, or parts, of the urinary system involving the kidney and ureter - most extensive form is a single kidney presenting with 2 sets of calyces, 2 renal pelvi and 2 ureters - can be uni/bi lateral - usually an incidental finding but monitored in paeds due to its relationship with recurrent UTI
describe bladder adenocarcinoma
comprises 95% of tumours found in the prostate gland, affects men over 55yrs
as the prostate is connected to the urinary system via the seminal vesicles and vas deferens, a prostatic tumour often spreads by direct extension into the bladder and urethra
what is the best efficient modality for differentiation between benign and malignant prostatic tissue types
US
