Contribution of other modalities for pathology

Radioisotope scans

• US invaluable in assessing kidneys morphology but not renal function

• Diethylene triamine denta acetic acid (DTPA)=radioactive tracer

• IV injection as bolus to access renal perfusion, pelvicalyceal system dilatation and obstructive uropathy

• US images for further data of renal uptake, excretion and drainage, localised areas of poor function

Computer TomographyCyst• Cysts with complex

acoustic characteristic• Further evaluation the

calcified wall associate with malignancy

• Differentiate cyst from diverticulum as latter fill with contrast

• contrast showing parapelvic cyst location

Computer tomography

Benign focal renal tumours

• Angiomyolipomas with smaller & more echogenic (shadow) than carcinomas

• Ability to identify fact content of lesion

Computer Tomography

Malignant renal tract masses

• Small isoechoic massses miss by US

• Equivocal CT scan more sensitive in small lesion detection

• CT for staging purposes

• Identify primary & other smaller metastases not identified on US

Computer Tomography

• Renal tract inflammation

• Acute pyelonephritis indistinct between cortex & medullary pyramids for US

• CT detect subtle, inflammatory changes

• Focal pyelonephritis well demonstrated on CT

Computer Tomography

• Tuberculosis & Xanthogranulomatous pyelonephritis

• CT demonstrate subtle inflammatory changes affect calyces in early stages

• Defferentiate TB from XGP with more sensitive to extrarenal spread of disease

X-ray

• CXR demonstrat metastases in lungs

• Confirm presence of stones in renal tract (non opaque by US)

• Essential adjunct to investigate renal colic in obscured by overlying bowel

• More obvious staghorn calculi

IVU

• Cyst cause filling defect

• Miss small (benign) renal masses

• Best to confirmation of cause & identification of exact renal obstruction level

• Essential adjunct to investigate renal colic in obscured by overlying bowel

Angiography

• Severe stenosis difficult to identify colour flow in kidney

• Reduction waveform by velocity with tiny, damped trace

• Gold standard for stenosis

• Invasive & possibly toxic nature

• Only grade & treat after positive US scan

Patient Preparation & Management

Patient Preparation

• Wear comfortable, loose-fitting clothing • Eat only fat-free food the evening prior to your

examination • Do not eat anything after midnight the night• Following this, drink four 8 oz. glasses of water

at one sitting. • Do not empty or bladder again prior to the

examination

Patient Management

• Procedure takes 30 minutes• Lying down for the procedure • clear, water-based conducting gel to

transmission of the sound waves• transducer (probe) move over

abdomen• little discomfort, slightly cold and wet

with conducting gel• No ionizing radiation exposure

Role of radiographer

• Understand bubble physics and instrument settings – Optimizing the image requires a firm

understanding of how changing instrument settings will affect the bubble and your image

• Understand when contrast is indicated– As the front line user, should initiate the

decision to use contrast

Patient Selection

• Sonographer is in primary position to identify need for contrast enhancement– Suboptimal endocardial visualization

• Suspected intracavitary mass

• Order for contrast must originate from physician– Physician approval sought on a case-by-case basis– Standing order may be instituted to decrease overall

procedure time and increase patient throughput– Order may come from referring physician

Patient Selection Protocol for Contrast

• Patients with limited acoustic windows– Inadequate imaging of 2/6 segments in

any single view– Incomplete Doppler velocity profiles

• Proper equipment– Harmonics– Mechanical index display and adjustment

• Adequate training

Performing a Contrast Ultrasound Study

• Obtain physician order– May be a standing order where allowed

• Explain procedure to patient– Obtain informed consent if required

• Establish IV access• Determine optimal mode of administration

– Continuous infusion vs bolus

• Optimize equipment settings– Recognize and correct for artifacts

• Acquire images

Reference

• Bates, Jane A. (2001). Abdominal Ultrasound. London: Churchill Livingstone

• Taragin, Benjamin. (2003). Abdominal Ultrasound. Retrieved from http://health.allrefer.com/health/abdominal-ultrasound-info.html