CONVENTIONAL IMAGING OF THE
URINARY TRACT
By
Mohamed Abou El-Ghar; MD

CONVENTIONAL RADIOGRAPHY
 Images produced through the use of ionizing
radiation are called conventional radiographs.
 It is relatively inexpensive to produce, can be
obtained almost anywhere by using portable or
mobile machines, and are still the most widely
obtained imaging studies.
 They require a source to produce the x-rays (the
“x-ray machine”), a method to record the image.
 The major disadvantages of conventional
radiography are the limited range of densities it
can demonstrate and that it uses ionizing
radiation.

THE FIVE BASIC DENSITIES

BASIC DENSITIES

BIOLOGICAL EFFECTS OF RADIATION
 Radiation causes biological effects on a cellular
level either (1) by directly damaging molecules or
(2) by indirectly creating free radicals to disrupt
cellular metabolism.
 Deterministic effects (nonrandom): This is
damage that occurs when a threshold level is
met. Both the probability and the severity of the
effect are proportional to increasing dose, where
the dose is usually given in one exposure or several
exposures over a very short period of time.

BIOLOGICAL EFFECTS OF RADIATION
 Stochastic effects (random): Damage that may
occur at any level of exposure, without a
threshold dose.
 These effects occur by chance, and while their
probability increases with an increasing dose,
their severity is independent of the dose.
 These effects are due to damage of cellular
components, usually DNA, by free radicals, leading
to abnormal cell function if repair is incomplete or
incorrect.

CONVENTIONAL TECHNIQUES
 Intravenous Urography (IVU).
 VCUG.
 Retrograde urethrography.
 Others; Retrograde pyelography, loopography
and angiography.

ANATOMY

IVU
 IVU or IVP?.
 Contrast media or dye?.

IVU: INDICATIONS
 RVH
 Prostate enlargement
 UTI
 Abdominal mass
 Evaluation of renal
papillae.
 Before endourology.
 Less common:
- UT obstruction
- Renal trauma
- hematuria
- congenital anomalies
- urinary fistula
Superseded Indicated

CONTRAINDICATIONS
 Serum creatinine > 1.2-1.5 mg/dl
 Hepatorenal syndrome
 Multiple myeloma
 Pregnancy
 Thyrotoxicosis
 Diabetes
 Previous allergy to the contrast media
 Generalized allergic conditions

IVU: PROCEDURES

INTRAVENOUS UROGRAPHY (IVU)
 IVU should be tailored
to answer a specific
clinical question.
 The preliminary kidney,
ureter, bladder (KUB)
radiograph is an
indispensable part of
the sequence.

PLAIN RADIOGRAPHY(UTP)
- from the suprarenal
region to a level below
the symphysis pubis.
- The patient should void
immediately prior to
examination.
- may require additional
images

KUB
 Additional views:
- Oblique conventional
radiographs.
- Nephrotomogram.
- Open bladder film.

KUB ANALYSIS
 Musculoskeletal: evaluate all bone elements.
 Psoas muscle margin: straight, convex or absent.
 Intestinal gas: overlap, displaced.
 Kidneys
 Calcifications: overlying the UT or outside.
 Gas shadow: abnormal air at UT.

IVU

IVU
 Kidney film 3 min.
 A KUB radiograph is obtained to assess temporal
symmetry and opacification.
 Compression? (Contraindications ).

IVU
 Bladder film early
(suspected bladder
lesion).
 KUB after release of
compression( 15 min).
 delayed images for
bladder distention, and
oblique, prone, or post-
void images.

INTERPRETATION OF IVU
 Renal size.
 position of the kidney.
 Renal parenchyma at
nephrographic phase.
 Renal contour
(interpapillary line).

NEPHROGRAM
 Visualization of the opacified renal parenchyma.
 Absent nephrogram:
- Technical.
- Renal failure.
- Renal artery occlusion.

TYPES OF NEPHROGRAM
 Faint persistent nephrogram: hypotension, impaired
function ( High dose urography).
 Increasing dense nephrogram: distal obstruction,
RAS, Renal vein thrombosis.
 Immediate dense: ATN, APN.
 Striated nephrogram: APN, Acute extrarenal
obstruction, ARPKD, Medullary sponge k.
 Patchy nephrogram: Vasculitis.
 Cortical rim nephrogram: Infarction.

10 min 12h

IVU
 Renal parenchyma:
- Decreased thickness.
- Increased thickness.
- Beak sign.
- Double contour sign.

IVU
 Kidney position.
 Longitudinal axis.

IVU
 Evaluation of the PCS.
- Obstruction (round
forniceal margin).
- CM inside the papillae.
- Parenchymal cavities
filled with CM.
- Filling defect.
- Phantom calyx.

GRADING OF HYDRONEPHROSIS

URETERS
- peristalsis.
- Stasis of contrast.
- Medial deviation.
- Lateral deviation.
- Anatomic narrowing.
- Ureter diameter (8mm).
- Filling defect.

 Medial deviation of the ureter should be considered
when the ureter overlies the ipsilateral lumbar
pedicle.
 lateral deviation should be considered when the
ureter lies more than 1.5 cm beyond the tip of the
transverse process.

BLADDER
- Bladder contour.
- Wall thickness and
irregularities.
- Extrinsic compression.
- Filling defect.
- Post-void ( residual
urine, upper tract
dilatation).

IODINATED CONTRAST MEDIA
 Water soluble, they
into negative
and positive ions which
attract the negative and
positive poles of the
water molecules.
 Do not dissociate and
are rendered water
soluble by their polar OH
groups.
Ionic contrast media Nonionic contrast media

CM ADVERSE REACTION

TYPES AND FREQUENCY OF ACUTE
REACTIONS
 Acute idiosyncratic systemic reactions (also described as
allergy-like or anaphylactoid) are defined as
unpredictable reactions which occur within 1 h.
 Chemotoxic reactions, are dose-related and dependent
on the physico-chemical properties of the contrast
medium.

ACUTE IDIOSYNCRATIC REACTIONS
 Mild or minor reactions include nausea, mild vomiting,
urticaria and itching.
 Moderate reactions include more severe vomiting,
marked urticaria, bronchospasm, facial or laryngeal
oedema, and vasovagal reactions.
 Severe reactions include hypotensive shock, respiratory
arrest, cardiac arrest and convulsions.

RISK FACTORS FOR ACUTE IDIOSYNCRATIC
REACTIONS
Type of Contrast Agent.
Previous Contrast Medium Reaction.
Asthma.
Allergy.
Drugs( B Blockers, Ca channel antagonist
and Inter leukin).

PREVENTION OF ACUTE IDIOSYNCRATIC
REACTIONS
 In any patient at increased risk of contrast medium
reaction, especially if there has been a previous reaction
to an iodinated contrast agent, use other modalities.
 If iodinated contrast medium is still deemed essential the
risk of an acute reaction can be reduced by an
appropriate choice of contrast medium and
premedication.

CHOICE OF CONTRAST MEDIUM
Nonionic low osmolality agents which are
associated with a four to five times lower risk
of reactions.
Nonionic CM is preferred specially if there is
history of previous reaction, allergy or
asthma.
Previous history to nonionic CM?.

PREMEDICATION
 Most frequently steroids with or without additional H1
antihistamines have been recommended.
 In severe reactors to ionic CM, steroids should be given
12&2 h before contrast medium.
 The minimal effective time interval between steroids and
CM is considered unlikely to be less than 6 h.

PRETESTING AND INJECTION RATE
 Pretest dose?.
 Rate of injection?.

GENERAL CONSIDERATIONS
 Use nonionic contrast media.
 Keep the patient in the Radiology Department for
30 min after contrast medium injection.
 Have the drugs and equipment for resuscitation
readily available.

MANAGEMENT OF ACUTE CM ADVERSE REACTIONS
 The adverse event that occurs within 60 min of an
injection of contrast medium.
 The mild reactions include flushing, nausea, arm
pain, pruritus, vomiting, headache, and mild urticaria.
They are usually of short duration, self-limiting and
generally require no specific treatment.

TREATMENT OF SPECIFIC REACTIONS
 Nausea and Vomiting ( self limited, ? Anti-emetic).
 Cutaneous Reactions ( treat if extensive).
 Bronchospasm ( O2, bronchodil., ? Adrenaline).
 Laryngeal Edema ( i.m adrenaline, O2).
 Hypotension ( rise leg, rapid IV fluid).
 Vagal Reaction ( as hypotension+ I.V atropine).
 Generalized Anaphylactoid Reactions ( airway, O2,
rapid IV fluid, i.m adrenaline, ECG monitor).

LATE ADVERSE REACTIONS
Reactions occurring between 1 h
and 1 week after contrast medium
injection.
They are mainly mild or moderate
skin reactions and usually resolve
within 3–7 days.

CI NEPHROPATHY
 Thee reduction in renal function induced by contrast
media which occurs within 3 days following
administration of contrast media in the absence of
an alternative etiology.
 Most episodes of CIN are self-limited and resolve
within 1–2 weeks.
 A persistent nephrogram on plain radiography or
CT of the abdomen at 24–48 h.

PREDISPOSING FACTORS
 Pre-existing renal impairment [> 1.5 mg/dl], particularly when
secondary to diabetic nephropathy.
 Large doses of contrast media and multiple injections within
72 h.
 The route of administration (IA > IV).
 Dehydration and CHF. Hypertension, hyperuricemia and
prteinuria. Multiple Myeloma.
 Nephrotoxic drugs.
 Type of CM.

PREVENTION OF CIN
 Extracellular volume expansion, the choice of
normal (0.9%) saline when intravenous hydration is
used,
 The choice of low or iso-osmolar nonionic contrast
medium,
 Lowest contrast medium dose consistent with a
diagnostic conclusion or a therapeutic goal.

EXTRAVASATION OF CM
 Elevation of the Affected Limb.
 Application of hot & cold fomentations.
 Topical antibiotic.
 Topical Hyaluronidase.
 Aspiration of subcutaneous fluid.

VOIDING
CYSTOURETHROGRAPHY

VCUG is commonly performed in children
with prenatally diagnosed hydronephrosis,
urinary tract infections, and voiding
abnormalities.
The procedure should include assessment
of the spine and pelvis; masses or opaque
calculi; bladder capacity, contour, and
emptying capability; presence and grade of
reflux; and urethral appearance.

PRELIMINARY IMAGING
Clinical data and results of prior
imaging studies should be reviewed
before starting the examination.
Preliminary abdominal imaging usually
precedes catheterization.

CATHETERIZATION
Aseptic condition.
A 5-F feeding tube is appropriate in children
under 3 months of age and an 8-F feeding
tube in all other children.

BLADDER FILLING
Early Filling
Several seconds after the contrast
material begins to flow, the minimally
filled bladder is imaged in the AP view.
A ureterocele or bladder tumor that is
well seen during early filling may
become obscured as more contrast
material enters the bladder

INTERMEDIATE FILLING
Vesicoureteral reflux can be
seen on oblique radiographs
obtained just before voiding
and can be graded after
voiding with the International
Reflux System.

PREVOIDING IMAGING
If reflux is observed during late bladder
filling, the ipsilateral renal fossa may be
imaged in the anteroposterior projection
prior to voiding.

IMAGING DURING VOIDING
Bladder capacity={Age(ys)+2}x30.
A smaller than expected voiding volume
may also indicate a neurologic abnormality
(spastic bladder) or active bladder
infection.

POSTVOIDING IMAGING
At the conclusion of voiding, each
renal fossa should be imaged. Still
images may demonstrate reflux that is
not appreciated at fluoroscopy as well
as other anomalies or abnormalities.

ABDOMINAL RADIOGRAPHY IN EMERGENCY

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