Renal radiology

1. NTAMBI MUSA

2. Objectives
Definition
Indications
Contraindications
Procedure
Mainly a recap of yesterday’s lecture

3. WHAT IS IVU?
 It is the radiographic examination of the urinary
tract including the renal parenchyma, calyces,
pelvis, ureters and the urinary bladder after the
intravenous injection of the contrast media.
 A series of plain films of the renal system, taken
after administration of an intravenous injection of
water-soluble iodine-containing contrast medium

4. Terminology
Urogram: Visualization of kidney parenchyma,
calyces, pelvis, ureters resulting from IV injection of
contrast.
Pyelogram: Describesretrograde studies visualizing
only the collecting system.
So, IVP is misnomer, should be IVU

5. INDICATIONS for IVU
1. Persistent flank pain
2. Haematuria
3. Renal and ureteric calculi
4. Ureteric fistulas and stricutures
5. Complex urinary tract infection
6. Demonstration of renal collecting
system and ureters.

6. Contraindications for IVU
1. Renal failure (raised serum creatinine level >1.5 mg/dL)
2. Hepatorenal syndrome
3. Previous allergy to the contrast agent/iodine
4. Generalized allergic conditions
5. Multiple myeloma
6. Pregnancy
7. Infancy
8. Thyrotoxicosis
9. Diabetes
Note: There is no absolute contraindication

7. Advantages of IVU
1. Clear outline of the entire urinary system so can see
even mild hydronephrosis.
2. Easier to pick out obstructing stone when there are
multiple pelvic calcifications.
3. Can show non-opaque stones as filling defects.
4. Demonstrate renal function and allow for verification
that the opposite kidney is functioning normally.
5. Cheap in comparison to modern modalities

8. Disadvantages of IVU
1. The need for IV contrast material
2. May provoke an allergic response
3. Multiple delayed films (In case of blockages, can take
hours as contrast passes quite slowly into the blocked
renal unit and/or ureter.)
4. May not have sufficient opacification to define the
anatomy and point of obstruction.
5. Requires a significant amount of radiation exposure
and is not be ideal for young children or pregnant
women

9. Contrast media
Iodine is the main element that imparts the radiopacity
Types:
Ionic; e.g: Urografin, Angiografin, Urovision and Triovideo
conary etc… They are cheap but they dissociate in solution
(ionise).
Nonionic; e.g: Iopamiro aka Iopamidol, Iohexal aka Omnipaque,
Iopromide aka Ultravist etc.
Merit: these LOCM do not dissociate in the body.
Demerit: More expensive than Ionic variants.
Dimers… Latest modification. Iso-osmolar

10. Patient Preparation
 Complete urine and blood examination to
assess the renal function.
 The patient is given mild laxatives(1-2 oz castor
oil) about twelve to twenty four hours before the
examination. (A night before the urographic
examination). Eliminates fecal material and
reduces amount of gas in bowel.
 The patient is kept nil by mouth over night and
is dehydrated by stopping the fluid intake.

11. Patient Preparation Cont.
 Most uroradiologist believe that with modern
contrast media over hydration should be
avoided and… Actually, dehydration is
unnecessary with modern CM.
 In practice pt. are advised to omit fluids after
11pm, omit breakfast which decreases chance
of vomiting and produce slight dehydration.

12. Patient Preparation Cont.
 The dehydration helps in better concentration of
the contrast and clearer x- ray pictures.
 The patient should not be dehydrated if
suffering from renal failure as it may lead to
severe fluid and electrolyte imbalance.
 Sensitivity to the dye (Hypaque or Urographin)
should be checked.

13. Preparations on day of
Procedure
 Evaluate the request form
 Greet the patient
 Take History again
 Previous reaction to contrast media
 Diabetes mellitus, myeloma, hyperuricemia,
sickle-cell disease
 Glomerular Function
 Assess if patient can excrete the dye

14. Patient Preparation Cont.
And what is pertinent Hx?
5. Remove jewelry, check attire, snaps, pins, NG tubes, etc.
6. Explain the exam in simple language (layman’s terms)
7. Questions?
urinary tract infection,
Renal mass, oliguria,
renovascular hypertension,
Renal calculi,
DM,
elevated creatinine or BUN,
haematuria,
bladder CA, prostate
enlargement, polycystic kidney,
8. Set technique before positioning
4. Have the patient void

15. Shielding
Shield gonads, keeping the shield below the superior
margin of the symphysis pubis.
Patient Position
Situate patient supine, with pillow for head, arms at sides away
from body, and support under knees to relieve back strain.
Part Position
• Align midsagittal plane to center line of table and to CR.
• Ensure no rotation of trunk or pelvis.
• Include symphysis pubis on bottom of IR without cutting off
upper kidneys. (A second smaller IR for bladder area may be
necessary on hypersthenic patients.)

16. Material / Equipment
High powered X-Ray generator set-up, typical 40-60 kW.
contrast (amount dependent on body weight, typically around
100cc)
Syringes, Cannula and alcohol wipes
tourniquet
emesis basin, towels, emergency drugs/crash cart, Emergency
drugs and equipment
lead marker set (anatomical and time)
compression device
10” x 12” & 14” x 17” cassettes
gonadal shields
positioning sponges
Abdominal compression equipment.
Pads and immobilisation aids
Venipuncture
Reaction
supplies
Filming

17. IVU scout and series.

18. Central Ray
• CR is perpendicular to IR.
• Center CR and IR to level of iliac crest and to midsagittal
plane.
• Minimum SID is 40 inches (100 cm).
Collimation
Collimate to IR or smaller if possible.
Respiration
Suspend respiration on expiration and expose.

19. SCOUT / PRELIMINARY
FILM
 Supine, full length AP of
abdomen in inspiration.
 The lower border of cassette is
at the level of symphysis
pubis and the x-ray beam is
centred in the midline at the
level of iliac crests.
 To demonstrate bowel
preparation, check exposure
factors and location of any
radiopaque material or
artefacts

20. Rationale of the scout film
Demonstrate:
 Calculus
 Skeletal abnormality
 Intestinal gaspattern
 Calcifications
 Abdominal masses
 Foreign bodies

21. If necessary the position of overlying opacities may be
further demonstrated by:.
 Supine AP of renal areas, in expiration. The x-ray beam is
centred in the mid-line at the level of lower costal
margin
 The examination should not proceed until these films are
reviewed and confirmed satisfactory.

22. Contrast media injection
 Low osmolar contrast media (LOCM)- 300- 600mgI/ml
 Adult dose : 50-100ml
 Paediatric dose : 1ml/kg

23. Informed Consent

24. Technique
 Venous access via the median antecubital vein
is the preferred injection site.
 The gauge of the cannula/needle should allow
the injection to be given rapidly as bolus to
maximize the density of nephrogram.
 Upper arm or shoulder pain may be due to
stasis of contrast in vein which may be relieved
by abduction of the arm.

25. Administration of CM
 Dose of 200mg of iodine per pound body wt-
dose of 20-30g.
 Injection completed within 60 sec-rapidly
injecting as bolus with 50 ml syringes.
 Slow injections decrease side effects but
provides less dense nephrogram
 Another method –drip infusion technique,
infusion kit with 40-50g iodine delivered in 250-
400ml fluid.

26. What to
watch for
Reactions can
develop quickly,
and patients
should not be
left alone.
From Patient Care in Radiography,
5th edition. pg.271.

27. Potential Contrast Reactions (and treatments for)
Though the incidence is lessened, reactions to nonionic contrast injections are
the same as for ionic agents. Most reactions occur within 5 minutes of injection.
Staying calm and reassuring is imperative to the patient’s well being.
Mild: metallic taste dizziness
flushing (slow, deep breathing) diaphoresis
nausea chills (blanket warmer)
vomiting (emesis basin) vasovagal (fear of needles)
Moderate: urticaria (benadryl) swelling of parotids
facial edema transient bronchospasm
transient hypotension delayed skin reaction (keep patients 20 min)
headache tachycardia
Severe: prolonged hypotension/circulatory collapse (Adrenaline [epinephrine]
improves cardiac output and relaxes bronchial smooth muscles).
pulmonary edema arrhythmias (Inderal)
angina (nitroglycerine) convulsions
severe bronchospasm (adrenaline) coma
cardiac arrest (sodium bicarbonate) paralysis
death

28. Physiology of excretion of
CM
 CM reaches renal artery in 15 sec.
Vascular nephrogram: Last btn a few seconds to 1
min, & coexists with the diffusion of CM
Total body opacification phase: CM is freely
filtered by the glomeruli
Tubular phase: Last for 1 min. CM is in proximal
and distal Convulated tubules
Pyelographic phase: CM in convulated system
reaches the calyces btn 2-3 min.

29. Radiographic Anatomy
of the urinary system
catheter
IVU Tomogram
Right Renal Arteriogram
Circulation of iodine contrast
before the nephron phase
(first appearance) of kidney in
an IVU
cortex
renal pelvis
nephron
“blush”
renal a.
Ureter major calyx
minor calyces
Ureteropelvic junction
(infundibulum)

30. Anatomy
Review

31. Film
Sequence
Routines are determined by department protocol, but a typical
sequence is:
 1-3 minutes Antero-posterior- film coned to the renal area
 5 minutes Antero-posterior-film coned to the renal area
 Apply ureteral compression
 10 minutes Antero-posterior
 Release compression
 “Flush”, “X” or “Release view”- - full length view at 20 minutes
 Upright post void Antero-posterior

32. Film
Sequence
Immediate film. AP of the renal areas.
Taken ~ 10–14 s after the injection (approximate ‘arm-to-
kidney’ time).
Aims to show the nephrogram at its most dense - i.e. the
renal parenchyma opacified by contrast medium in the
renal tubules.
Tomography may assist in evaluation of the renal outline or
possible masses (or ultrasound if readily available).
5-min film. AP of the renal areas. Gives an initial
assessment of pathology—specifically the presence or
absence of obstruction before administering compression.

33. Film
Sequence
A compression band is then applied, positioned midway
between the ASIS - i.e. over the ureters as they cross the pelvic
brim.
Aim is to produce pelvicalyceal distension.
10-min film. AP of the renal areas. There is usually adequate
distension of the pelvicalyceal systems with opaque urine by this
time.
Compression is, contraindicated if:
(a) after recent abdominal surgery
(b) after renal trauma
(c) there is a large abdominal mass or aortic aneurysm
(d) when the 5-min film shows already distended calyces
indicative of obstruction

36. Compression is released when satisfactory demonstration of
the pelvicalyceal system has been achieved.
If the compression film is inadequate, the compression
should be checked and repositioned if necessary and a
further 50 mL of contrast medium administered and a
repeat film taken after 5 min.
Release film. Supine AP abdomen taken immediately after
the release of compression. Taken to show the ureters.
If film is satisfactory, the patient is asked to empty the
bladder.

38. cortex
Rt iliac
crest
Hilum *
medulla
Lower pole
rt. kidney
Upper pole
rt. kidney
* In middle of medial border,
superimposed on psoas m.
IVU Tomogram, late nephron
phase, collecting system
beginning to visualize
Release film with full bladder
Lateral
border

39. After Micturition (Post void) film. Full-length Erect or supine
AP abdomen.
Aimed at assessing bladder emptying, to demonstrate
drainage of the upper tracts, to aid the diagnosis of bladder
tumours, to confirm ureterovesical junction calculi, and
(though uncommonly), to demonstrate a urethral
diverticulum in females.

41. Additional Images.
1. 35° posterior oblique of the kidneys, ureters or bladder—for
equivocal collecting system lesions or localization of calculi
2. Tomography - if renal outlines are not well seen
3. Prone abdomen following the release film—may improve
visualization of distal ureters
4. Delayed films at increasing (doubling of time intervals) up to 24 h
after injection in renal obstruction
Variation
Renal colic—a limited study may be performed: preliminary films;
20-min full length (no compression); postmicturition full length;
delayed films up to 24 h as required to show level and cause of
obstruction.

42. RPO AND LPO POSITIONS: INTRAVENOUS (EXCRETORY)
UROGRAPHY
Pathology Demonstrated
Signs of infection, trauma, and obstruction of the elevated kidney are
shown. Also demonstrates trauma or obstruction of the downside ureter.

43. RPO

44. Summary of the Procedure
Scout Film
Injection of Contrast
Immediate Film
5-minute Film
10-minute Film
Release Film
Post-void Film

45. Radiographic Critique
Structures Shown: • Entire urinary system is
visualized from upper renal shadows to distal urinary
bladder.
The symphysis pubis should be included on lower
margin of the IR.
After injection, only a portion of the urinary system
may be opacified on a specific radiograph in the
series.
Position: • No rotation as evidenced by symmetry of
iliac wings and ribcage.

46. Radiographic Critique
Collimation and CR:
• Collimation borders to IR margins on top and bottom to
prevent cutoff of essential anatomy.
• Complete arch of symphysis pubis visible on bottom
margin of radiograph, with center of image at level of iliac
crest.
Exposure Criteria and Markers:
• No motion due to respiration or movement.
• Appropriate technique with short-scale contrast
demonstrating the urinary system.
• Minute markers and anatomical (R or L) markers visible on
all series radiographs.