Hematuria / Renal Stone

• Trauma
• Renal calculi
• Renal cancer
• Bladder stone or cancer
• Acute glomerulonephritis

Urine analysis is diagnostic showing red cells and red cell casts in acute glomerulonephritis

What is the common cause for painful hematuria?

• Calculi in GU tract

What is the common cause for painless hematuria?

• Renal cancer

What are useful imaging modalities to investigate renal stones?

• KUB plain film
• Non contrast CT abdomen
• Ultrasound

KUB Plain film

Kidney Stone

• Allows for the evaluation of urinary tract stones.
• Ninety percent or more of urinary-tract stones are radio-opaque.
• The degree of opacity varies depending upon the composition of stone (calcium content of the stone).
• Uric acid stones (8%) are radiolucent.
• Visibility of stones depends not only on the degree of opacity, but also on their sizes and positions relative to other abdominal structures.
• An opaque stone needs to be approximately 2mm in its largest diameter to be visible on an abdominal film.
• Poor sensitivity for ureteral stones.

Non-contrast helical computed tomography of the abdomen (NCHCT)

• Greater sensitivity than KUB for ureteral stones
• Most sensitive and specific (95-97% and 96-97% respectively)
• Because abdomen and pelvis are scanned in one to two breaths, virtually eliminates the problem of respiratory motion
• Can be performed quickly, eliminating potential delays
• Safe, because eliminates the risk of contrast, which includes allergic reactions and toxicity
• Detects non-urologic pathology - including appendicitis or ovarian cysts
• While more expensive than a KUB, comparable to a excretory urography and ultrasound
• Able to detect all stones regardless of composition, except those associated with indinavir therapy for HIV infections

Bilateral Renal Pelvis Calculi

Arrowheads: There is soft tissue infiltration secondary to extravasations of urine around both renal pelvis.

Ultrasound

• Preferred procedure in pregnant women and in patients allergic to IV contrast.
• Not dependent on the composition of stones and detects uric-acid stones as well as calcium stones.
• Stones are seen as highly echogenic foci and often produce distal acoustic shadowing
• Not always possible to distinguish small stones from arterial calcifications, pericalceal fat, or crystal-laden calceal sub mucosal plaques.
• Detects hydronephrosis
• Generally good sensitivity .
• Ureteral stones are difficult because of overlying gas

Kidney Stone  

US: Lower pole calculus.

Sensitivity, specificity of procedures.

 Utility of imaging procedures

Indicate when you would select each procedure.

Controversy exists over the proper procedure sequence. With the addition of non-contrast helical CTs, some advocate CT as the first-line procedure. However, most physicians continue to utilize plain radiographs of the abdomen (KUB) as the initial screening imaging procedure.