Functional & Morphological Flashcards
What is the primary purpose of morphological imaging in renal assessment?
Visual assessment of renal size, shape, and location
Provides anatomical information about space-occupying lesions, such as cysts.
What type of imaging is primarily performed in children?
Morphological imaging
Also referred to as ‘renal cortex/cortical imaging’.
What does functional imaging assess?
Qualitative and quantitative assessment of renal function
Both at the nephron/cellular level and globally/whole-kidney.
What are the two key measurements functional assessment techniques allow for?
Indirect measurement of effective renal plasma flow (ERPF) and indirect or direct measurement of glomerular filtration rate (GFR)
What radiopharmaceutical is primarily used for morphological imaging?
Tc99m-DMSA (dimercaptosuccinic acid)
Demonstrates relatively slow clearance from blood.
Which radiopharmaceutical is ideal for estimating ERPF?
Tc99m-MAG3 (mercaptoacetyltriglycine)
Rapidly excreted from blood via tubular secretion and glomerular filtration.
What is the primary mechanism of uptake for Tc99m-DTPA?
Glomerular filtration (100%)
What is the ideal patient positioning for a renal scan evaluating a transplanted kidney?
Supine with the detector positioned for anterior imaging over the pelvis
What is the significance of hydration in patient preparation for renal imaging?
Hydration is key to ensure accurate imaging results
Patients should drink several glasses of water the morning prior to the scan.
What should be done if a patient is receiving ACE inhibitors before a renal scan?
Stop prescribed ACE inhibitors 24-48 hours prior to the scan
Always consult with the patient’s physician before instructing a patient to stop any meds.
What characterizes a normal renal scan?
Prompt and symmetric uptake of tracer in both kidneys
Activity should begin to move from cortex to renal pelvis within 5-10 minutes.
What is the adult dosage of intravenous furosemide (Lasix) for diuretic renography?
40 mg (may be reduced to 20 mg if patient has only 1 kidney)
What does a normal renogram indicate?
Bilateral prompt tracer uptake and bilateral washout (T1/2 < 20 min)
What is a common complication of renal transplantation that can be evaluated by nuclear medicine?
Organ rejection
What does a non-viable or rejected kidney demonstrate in imaging?
Low or no radiotracer uptake
What is the primary method used for GFR quantitation?
Tc99m DTPA
Filtered exclusively from the plasma by the glomerulus.
What is the main advantage of camera-based clearance methods?
Easier to perform and less time consuming
Does not require the collection of blood or urine samples.
What is the typical image acquisition protocol for a basic renal scan?
Initial flow – 1-2 seconds/frame for 1-2 minutes and dynamic – 60 sec/frame for 30-60 minutes
What is the indication for morphological imaging?
Evaluation of space-occupying lesions or functioning pseudotumors
What characterizes abnormal findings in morphological imaging?
Acute pyelonephritis, focal cortical defects, multi-focal cortical defects, diffusely decreased activity
What does a normal DMSA scan show in terms of split function?
Approximately 50-50 split between right and left kidneys
What is the typical imaging procedure for morphological imaging?
Static imaging at 2-4 hours post-injection with high-resolution and/or pinhole collimator
What does the ring of increased activity (‘rim sign’) indicate in renal transplant imaging?
Inflammation surrounding an infarcted kidney
