Transcript usrenal
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 Tomography Cyst • 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/abdomi nal-ultrasound-info.html