KUB Radiography and Anatomy

WHAT MUST THE EXAMINATION ANSWER?

can prevent the wrong protocol even when the modality is correct

INFORMATION THAT CHANGES THE EXAMINATION

translates the clinical question into phases, sequences, views, timing, and dose.

does not have contrast

what is shown in the middle

what is shown on the right image

include both kidneys and the bladder region

Coverage and exposure

KUB LIMITATIONS–AND THE ESCALATION RULE

Shows iodinated contrast moving through the urinary tract during lling, drainage, or voiding.
Enables real-time positioning and targeted spot images.

FLUOROSCOPIC EXAMINATION IN FOUR MOVES

What IVU demonstrates

timed examination: uptake, concentration, excretion,,and drainage.

more superior that IVU to show urinary tract and surrounding tissues cross sectionally

reference image for every subsequent phase

patient-specic; preparation should never be reduced to a single laboratory value.

FIRST PHASE: NEPHROGENIC PHASE

● Opacication of the bilateral kidneys
● It reects renal perfusion, ltration, and tubular concentration
● But it is not a direct measurement of the eGFR

STEP 4: EARLY EXCRETORY/PYELOGRAPHIC PHASE

Calyces and renal pelvis begin to opacify, proximal ureters may appear intermitently with peristalsis

Use only when the added upper-tract details are needed. Avoid if obstruction or trauma is suspected

Done in 30 degrees, problem-solving projection

STEP 5: FULL-LENGTH EXCRETORY IMAGE

Collecting systems, ureters, bladder = assessed on a full-length image; ureteric lling may remain segmental

○ Poor or asymmetric renal function.
○ Suspected obstruction with incomplete ureteric opacication.
○ Possible urinary leak, stula, or ectopic insertion.

used to check for the residual volume (quantify)

urinary retention

Retrograde contrast dye injected through a urinary catheter to outline the bladder. It is used to check for bladder leak, trauma, fistula, structural or functional abnormalities

Assessing bladder leak after trauma

postoperative injury,

evaluate presence or absence of Vesicoureteral Reux (VUR)

VESICOURETERAL REFLUX GRADING

if tissue remains obstructive
after birth or initial treatment—is a congenital birth defect
affecting only males where extra aps of tissue block the
urethra.

➢ Elongated urinary bladder with conical shape towards
dome of the bladder like a tree. Bladder wall hypertrophy
gives rise to an irregular outline.
➢ Typically occurs in those with sacral abnormalities at birth.
➢ Diagnosed through voiding cystogram

Christmas tree or pine cone bladder.

Fluoroscopic X-Ray Examination that inserts catheter to
the penis to inject contrast to check for damage,
narrowing and blockage

abnormal narrowing of urethra caused by scar tissue; More common in males than in females

Can guide stent placement or sampling—but requires
instrumentation; Evaluates upper urinary tract

Assesses drainage, obstruction, leak, and catheter position.

Known radiopaque stone follow-up, Device position:

New acute ank pain

Bladder leak

Reux or voiding urethra

Anterior urethral trauma/stricture

BLADDER ULTRASOUND: METHOD OF EXAMINATION

Cortex thickness

parenchymal thickness

well-distended adult urinary bladder typically holds

Wall thickness of bladder

Ureteric jets can be assessed using

➢ Dilation of renal pelvis and calyces.
➢ Renal cortical thinning in chronic severe disease.
➢ Bladder distension, ureteric jets, or a visible,proximal/distal cause in selected patients.

an anatomical sign

➢ Useful for selected focal renal lesions, trauma, perfusion,
transplant questions.

Excellent detection of calculi, gas, hemorrhage, fat, and calcication.

Patient with nephrolithiasis

Hounseld unit (HU) of 1Uric acid stones

Hounseld unit (HU) of Calcium oxalate stones

can be used to predict responsiveness to shockwave lithotripsy

Morphologic detail of renal parenchyma and collecting system

Important nephrographic parameters:

RENAL CT PHASE 0 : UNENHANCED BASELINE

Unenhanced renal parenchyma. We see stones, fat, hemorrhage, gas, and calcication; retain native attenuation.

ARTERIAL PHASE

BEST FOR:
○ Renal arteries, active bleeding, aneurysm, stenosis,
and planning.

RENAL CT PHASE 1 : CORTICOMEDULLARY PHASE

EXPECTED: Cortex enhances strongly while medulla remains lower in atenuation. Vessels are conspicuous.
➢ ➢ BEST FOR: Hypervascular masses, vascular anatomy, cortical perfusion, and trauma.

PORTAL VENOUS PHASE

➢ EXPECTED:
○ Abdominal viscera and veins enhance well. Renal parenchyma approaches uniformity.
➢ BEST FOR:
○ Infection, complications, venous thrombosis, trauma, and metastases.

RENAL CT PHASE 3 : NEPHROGRAPHIC PHASE

➢ EXPECTED:
○ Cortex and medulla enhance more uniformly, increasing contrast between parenchyma and many lesions.
➢ BEST FOR:
○ Renal masses, infection, infarct, and laceration.

DELAYED OR EQUILIBRIUM PHASE

➢ EXPECTED:
○ Vascular contrast equilibrates. Some lesions wash out or enhance progressively. Early urine may opacify.
➢ BEST FOR:
○ Washout, delayed enhancement, renal or adrenal questions, and brosis.

RENAL CT PHASE 3 : NEPHROGRAPHIC PHASE

➢ EXPECTED
○ Contrast reaches calyces, renal pelves, ureters, and bladder. Filling defects happens due to peristalsis
➢ BEST FOR
○ Urothelial lesions, collecting system, ureteric narrowing, and leak.

TARTGETED DELAY PHASE

➢ EXPECTED
○ Additional opacication may reveal slow excretion, a distal ureter, or a leak absent earlier.
➢ BEST FOR
○ Obstruction, ureteric injury, postoperative leak, or delayed excretion

Renal gas or your Emphysematous pyelonephritis

fat stranding

Purpose
○ Hematuria or suspected upper-tract urothelial disease.
○ Assess kidneys, collecting systems, ureters, and bladder.
○ Detects lling defects, wall thickening, obstruction, or another cause.

CT anatomy: unenhanced axial image

nephrographic phase