Radio logical investigations of urinary system
There are 4 main radiological Ix:
1 —IVU: Intravenous urography. 2- U/S 3-CT scan 4-Radioisotope scan. Others (not frequently used): MRI, arteriography, antegrade or retrograde pyelogram.
IVU STUDY OBJECTIVES
I INDICATIONS 1-Renal colic to visualize stones or obstructions 2-Heamaturia Recurrent UTI to assess congenital anomalies strictures or urothelial lesions 3- Renal obstruction e.g. renal mass 4-assessment of renal outline pylocalyceal system ureters bladder urothelium Others e.g. 5- Prostatitis 6-Neurogenic bladder 7-Trauma IVU is not indicated in Pylonephritis Renal failure Renal parenchymal disease Allergy to contrast
ADVANTAGE Widely available Excellent to identify uroepithelium Can visualize the whole length of ureters Can quantify the degree urinary tact obstruction
DISADVANTAGE Need for patient preparation Risk of radiation Contrast media problems such as allergy May get suboptimal results due to 1. Patient movement Overlying bowel gas 2. Poor concentration media due to poor renal function .
PATIENT PREPRATION 1. Laxatives is taken 24 hr before the examination Nil by mouth for 4-6 hr before the examination 2. 3.The patient should be ambulant as long as possible to decrease air swallowing 4.Certain measures is taken to certain group of patients e.g. DM and children Note ; in renal failure patient we give double dose of contrast 6oomg \kg Contrast is non ionic low osmolar water soluble contrast
BASIC PATIENT POSITION The patient must lie supine at mid line of table The vertical central ray is centered in the midline at the level of L3 at the lower costal margin, It may be necessary to alter the centering position to ensure the upper margin of the renal outlines are visible and the symphysis pubis. Exposure is made on suspended expiration Plain film : to show : Calcification 1-T.B 2-stone 3-hydatid cyst 4- tumors 5- fibroid in female Abdominal cavity 1- kidney outline 2- shadow of psoase muscle 3- bones Contrast injection about 50-100 cc over 10min time ? Nephrographic phase 1st flm 1-size &position of kidney Congenital malposition ;displacement by retroperitoneal mass AFTER 5MIN 2ND FILM ? film of pelvicalyceal system phase normally the minor calyceal system are curved because of pressure effect of pyramid 1- straight or convex (hydronephrosis) 2-sloughed(acute tubular necrosis) 3- pelvis is funnel shape so we look for stones ; masses ;tumors AFTER 15 MIN. ? full length IVU show 1- ureter 2- urinary bladder dilatation ;stone ; prostate ? Several films taken according to the conditions we phase ? Prone film for ureter ? Oblique stones ? I-U/S: Non invasive. cheap &easy Indication : 1. Patient with urinary symptoms. 2. Follow-up after lithotripsy 3. Patient with renal transplant to check rejection, stone & hydronephrosis. 4. Renal failure ? 5. Patient with recurrent UTI (in children) to diagnose reflux. In U/S the right kidney appear in relation to the liver & the left in relation to spleen. the right kidney appear darker than the (kidney cehogenicity is less ), with smooth outline, surrounded by fat renal sinus (vessels), length 9- 12 cm adult &decrease with age. Pelvicalyceal system doesn’t appear if normal. If it appears, means there’s dilation. *overfilled bladder may look like hydronephrosis so don’t judge, ask patient to void first. *stones> 5mm can be detected as sharp acoustic shadow. *U/S can also detect renal tumor, cyst hydronephrosis, 4rasitional cell CA, hypernephrorna. *The ureter can’t be seen in U/S except for its upper 3cm & the lower part in the bladder. In the bladder we see if there’s congenital anomaly, stone, tumor (prostatic). *There are no contraindications for U/S except for gassy intestine. III CT scan: Used for 1. Staging of tumor. 2. Detection of radiolucent stones (xanthine & uric acid stones). 3. Retroperitoneal mass, fibrosis 4. Sagittal reformal (to see kidney in lateral viewer), coronal reformat. 5. Renal trauma (bleeding, hernatoma). in CT scan we 1 take a plain CT without contrast to see if there’s calcification. IV Radioisotope: mainly for function of the kidney or when we can t do IVU. We inject Tc 99 DFPA intraenously & only the functioning part of the kidney will appear. V MRI: Two main indications 1. Renal vasculature before transplant for both the donor & recipient. 2. Renal artery stenosis (5 mm normally) with post stenotic dilation If we want to do operation, we do angiography also. VI- Antegrade & retrograde pye1oam: Direct injection of contrast medium into the collecting system from above or below. Antegrade pyelography requires insertion of a fine needle into the pelvicalyceal system under U/S or radiographic control. Retrograde pylography can be performed by inserting catheters into the uretric orifices at cystoscopy. Pylography mainly used to detect level of obstruction. In the presence of obstruction, percutaneous nephrostomy drainage can be stablished & stent can be passed through any obstruction. VlI- micturating cyst ourethrography: For children with — Reflux —Post urethral valve