Contrast Imaging of the Urinary Tract Flashcards
What are the three types of Cystography available?
Negative Contrast Cystography
Positive Contrast Cystography
Double Contrast Cystography
When is Excretory Urography indicated?
To visualise the upper urinary tract such as kidneys and ureters
Good for diagnosing Haematuria, Ectopic Ureters and Uroabdomen (leakage of urine into the peritoneal cavity)
What form of contrast is used for Urography?
Iodine based- positive or negative contrast
Why is Barium Contrast not used in Urography?
Barium contrast agents may cause peritonitis if they leak into the peritoneal space hence why water-soluble contrast is generally preferred
What is the risk with using an Ionic Iodine based contrast media?
Has a higher osmolarity than plasma so can draw water out and cause dehydration
What is necessary pre operatively to prepare for Excretory Urography?
Food should be withheld 12-24 hours before
Empty the colon via an enema 1-2 hours prior
Can also perform a Pneumocystogram (fill air with bladder) for better contrast imaging
(and obvs GA)
Briefly describe how Excretory Urography is performed.
IV Bolus injection of the contrast medium is given usually via the cephalic vein then radiographs are taken at timed intervals from ventral-dorsal and lateral projections before and at the end of the injection of the contrast medium
What are the three phases of Excretory Urography?
Vascular Phase- contrast is in the vessels
Nephrogram Phase- contrast is in the renal parenchyma
Pyelogram Phase- progressive increase in the opacity of the renal pelvis (more opaque than the parenchyma)
What is a Cystograph and when is it indicated?
fluorescence injected directly into the bladder via a catheter in order to image location, integrity of bladder and investigate incontinence, calculi and dysuria
What MUST be done prior to Cystography that differs from a Urograph?
Urine must be sampled prior to medium administration to check for any infections
What is the difference between positive and negative contrast cystography?
Negative contrast media is more radiolucent than surrounding tissues
Positive contrast media is more radiopaque and used to assess bladder rupture
What is Pneumocystography (negative contrast cystography) indicated for?
Assessment of distal ureters
Assessment of urinary bladder location
When is Pneumocystography (negative contrast cystography) contraindicated?
Urinary bladder rupture
Acute Haemorrhage
Mucosal Trauma
[don’t want to insert anything into bladder if its already damaged]
Briefly describe how a Pneumocystography is performed.
Patient is placed in left lateral recumbency to minimise the risk of air embolism (air or gas admitted in vascular system)
Slowly inject the catheter in- volume is based on external palpation
When is positive contrast cystography indicated?
Urinary bladder rupture
Evaluating the urinary bladder wall changes
Urinary bladder neck location in relation to the pelvis
