Urinary Tract Flashcards
Describe the technique of Intravenous excretion urography
50-100 ml adults 1 ml/kg children
No water 5 hrs prior but should drink
Preliminary - Aupine, full length AP of abdomen in inspiration - level of iliac creates, CR mid point.
IV bolus
AP of kidneys:
- Immediate film - 10-14 s after injection
- 5 min film - Then compression band if allowed (not in after Ab Sx , renal trauma , large mass, i prior AP already shows pelvicalyceal distension
- 10 min film - Compression released once systems opaque. If not further 50 ml contrast then repay film after 5 min
- Release film - Supine AP abdomen immediately after release of compression. Shows ureters. If good - empty bladder
- Micturation film - Full length supine AP abdomen. Assess emptying, show upper tracts, bladder tumours, confirm UV junction calculi, show urethral diverticulum in F
Additional:
- 35 degree PO of k U and B for collecting system lesions or to localize calculi
- Tomography - if renal outlines not well seen
- Prone abdomen following release may show better distal urethra
- Delayed (double time) up to 24 hr post injection - renal obstruction
How to differentiate between renal artery stenosis and vein thrombosis on Doppler ultrasound
Artery - main renal artery - increased PSV > 200 cm/s - > 50 % stenosis
Flank approach - Internal arteries - down stream changes - tarsus (slow rise) parvus (reduced peak) - prolonged acceleration time ( > 70 ms) indicates severe stenosis
Vein
Describe technique for standard diagnostic CT of urinary tract
- IV
- Keep patient supine
- Scanogram of CAP
- 100 ml IV LOCM
- Scan at 70 s (portal venous) - arterial phase of liver with suspected hypervascular mets
What phase is best for renal lesion characterization - CT
100 s p.i - nephrogenic - - prevent obscuration by corticomedullary differentiation
Describe technique for adrenal lesion characterization with CT
- Unenhanced can first to detect HU
- < 10 HU - highly specific for lipid rich adenoma - sufficient
- Washout CT to supplement - measure HU at 15 min post injection
Benign adenomas - rapid percentage washout - APW > 60 % or RPW > 40% on delay - highly specific
Alternative - chemical shift MRI may be used for characterization - MR spectroscopy (nuclear medicine)
What is the purpose of CT KUB and technique
Primary investigation of renal colic
Technique:
- No IV oral contrast
- Patient supine, prone if ? In VUJ or in VB
- Low dose - top of kidneys to bladder base - 5 mm slice thickness or less
3.
Technique for CT urogram
Phases: unenhanced
nephrogenic, delayed post IV contrast
- Diuresis - 500 - 1000 ml water - 45-60 min before injection
- Supine
- Non con - calcs
- 100 ml LOCM bolus
- Thin 1mm diaphragm to lower pole kidneys during nephrogenic phase- 100s post bolus or in portovenous at 70 s
- Delayed 1 mm upper pole of kidneys to bladder base 20 min post contrast- collecting system and ureter
- Source images and multiplayer review. MIP and surface shaded displays may help
To save radiation dose - split bolus technique - 50 ml of IV contrast 10-15 min before scan then 50 ml at time of scan - nephrogenic (renal parenchymal phase) and pylographic phase in same acquisition
Technique for CT angiogram of urinary tract
- Scan from upper pole of kidneys to aortic bifurcation
- Narrow collimation 1 mm
- 100-150 ml LOCM 300 at 3-4 ml
- Bolus tracking best / 20-25 s pi
Technique for MRI of urinary tract
Tailored to indication
- MR - T1 and 2 axial and coronal +/- FS
- Pre and post contrast T1 at 30 and 70 s
Technique for prostate MRI
Technique for MRI urography
Technique for MRI adrenals
Technique for MCUG
Preliminary image - coned view of the bladder
Technique to demonstrate vesico-ureteric reflux - confined to children
