Block 4 Unit 2 Notes.pdf

SKILLS Urologic and Nephrological Imaging 1. Discuss techniques, indications, contraindications, limitations, benefits, and risks of common uronephrological imaging studies including: KUB ○ In a KUB, the patient lies supine while 2-3 x-ray images are taken ○ KUB is indicated for abdominal pain in th...

SKILLS Urologic and Nephrological Imaging 1. Discuss techniques, indications, contraindications, limitations, benefits, and risks of common uronephrological imaging studies including: KUB ○ In a KUB, the patient lies supine while 2-3 x-ray images are taken ○ KUB is indicated for abdominal pain in the outpatient setting, kidney stones (mostly used in monitoring for stones), osseous abnormalities, and preliminary radiograph in series ○ Contraindications for the use of KUB is pregnancy ○ Patient does have to be able to hold breath for imaging in a KUB ○ The pros for a KUB is patient comfort, minimal radiation, and quick ○ The cons for a KUB is it provides a vague, non-specific imaging, and can produce poor imaging if the patient is constipated ○ KUB stands for kidney, ureters, and bladder Intravenous pyelography/urography (IVP) ○ In a IVP, patient will lies supine and be given IV contrast ○ A IVP requires bowel prep ○ A IVP is indicated for hematuria, recurrent UTI, flank pain and obstructive uropathy ○ A IVP is contraindicated in pregnancy, IV contrast allergy or iodine allergy, shellfish allergy, chronic kidney disease, Cr >2.0 ○ NOT commonly used since there are better imaging techniques Voiding cystourethrography (VCUG) ○ A VCUG requires the use of a urinary catheter to be able to push contrast media into the bladder. The imaging is then taken while voiding under fluoroscopy ○ A VCUG is indicated for young children with recurrent UTIs, or for monitoring post surgical corrections ○ A VCUG is contraindicated in pregnancy, shellfish allergy, iodine or contrast allergy ○ A VCUG is the only and best test for known vesicoureteral reflux ○ Cons for VCUG is possible UTI post-procedure Retrograde pyelography (RGP) ○ A RGP requires anesthesia ○ RGP is imaging of the ureters using contrast media directly into the ureters during fluoroscopy ○ Bowel prep is required for a RGP ○ You must educate your patients that a RGP procedure can cause mild hematuria, dysuria after procedure ○ A RGP is most commonly ordered in specialty urology care, not commonly used in primary care Renal ultrasound ○ A patient needs to arrive with a full bladder when getting a renal ultrasound and will void for a post-void residual imaging ○ A renal ultrasound can be dependant on body habitus and ultrasound technician ability ○ A renal ultrasound cannot evaluate ureters or surrounding anatomy ○ If a renal ultrasound is abnormal, the patient will need to be sent for a CT scan ○ A renal ultrasound is the test of choice for evaluation of renal failure ○ A renal ultrasound is the test of choice for unexplained acute kidney injury ○ A renal ultrasound is the test of choice for pregnant patients ○ A renal ultrasound is commonly used for children with suspected renal stones, renal cysts or palpable abdominal masses ○ A renal ultrasound is the screening test of choice for suspected PCKD ○ A renal ultrasound is the recommended initial modality for children and pregnant patients with microhematuria ○ A renal ultrasound can be used for evaluation of microhematuria Scrotal Ultrasound (not on objectives) ○ A scrotal ultrasound is indicated for for testicular pain, palpable mass, scrotal edema, scrotal trauma, and scrotal abscess ○ A scrotal ultrasound is the test of choice for testicular cancer and testicular torsion CT scan with or without contrast ○ A CT without contrast is indicated for possible kidney stones ○ A CT scan with or without contrast are contraindicated in pregnancy and in patients over 450 lbs ○ A CT with or without contrast should be cautiously used in children ○ A CT with IV contrast is indicated for patients with renal or adrenal masses, known malignancy staging, abdominal pain that is suspected appendicitis or diverticulitis, and trauma ○ CT of the abdomen with and without contrast is the preferred test for renal masses ○ Contraindications for a CT scan with contrast includes pregnancy, IV contrast allergy, chronic kidney disease or a CR > 1.9, or a prior history of CIN CT urogram ○ CT urogram is very similar to CT scans with/without contrast but has excellent specificity for renal, ureteral, bladder, and adrenal malignancy because the delayed phase will illuminate entire urinary tract and provide a 3D reconstruction ○ Indications for CT urogram are gross hematuria (meaning asymptomatic hematuria and smoker) and suspected pyelonephritis ○ Test of choice for microhematuria is the patient has asymptomatic microhematuria with a risk factors for a GU malignancy (such as smoking), but only if kidney function allows for the use of IV contrast CT Angiogram (not on objectives) ○ A CT angiogram is the best method for detecting renal artery stenosis and renal vein thrombus ○ CTA is the initial imaging study for renal artery stenosis ○ A CT angiogram should be performed in patients with unexplained progressive hypertension, since it could be renal artery stenosis MRI ○ A MRI should be cautioned for patients that are claustrophobic or unable to stay still ○ MRI cannot be used in patients with hardware and/or metal in the body ○ MRI is not commonly used in urology/nephrology, but can be used in a patient with chronic kidney disease with a suspicious renal or adrenal mass (with NO contrast) MR urogram ○ A MR urogram can be with or without contrast ○ A MR urogram is used to eliminate urinary system only and not the surrounding areas for evaluation ○ A MR urogram is okay to use in pediatric and pregnant patients ○ A MR urogram cannot reliably detect calculi 2. Nuclear medicine studies: Renal scintigraphy ○ A renal scintigraphy is only used for perfusion and function ○ A renal scintigraphy is the test of choice to determine obstructive versus nonobstructive hydronephrosis in children ○ This test detects obstructions by assessing images before and after administration of a diuretic ○ A renal scintigraphy is contraindicated in pregnant women or breastfeeding women Adrenal scintigraphy ○ NOT commonly used Captopril renogram ○ Captopril renogram helps determine if renovascular hypertension is present by comparing images before and after administration of Captopril (which is a ACE-inhibitor, given every 15 minutes for 1 hour) Renal angiography ○ In a renal angiography, dye is directly injected into the renal artery via a peripheral access in the groin to get a series of x-rays and fluoroscopy to watch for the dye to illuminate the renal artery ○ A renal angiography does require NPO for 6-8 hours before procedure, IV sedation, and leaving leg straight for 4-6 hours post procedure ○ Renal angiogram are indicated for confirmatory test following a CTA to look for renal artery stenosis ○ Renal angiography are contraindicated in pregnancy, therapeutic anticoagulation or antiplatelet therapy, bleeding disorders, IV contrast allergy, Chronic kidney disease, acute kidney injury or a Cr >1.9 ○ A con for renal angiogram is that CTA and MRA are better for initial tests 3. Counsel a patient on what to expect before, during, and after nephrourological imaging studies. 4. Compare and contrast “contrast induced nephropathy” and “nephrogenic systemic fibrosis” Contrast induced nephropathy ○ Contrast induced nephropathy is defined as “the impairment of kidney function after administration of IV contrast.” ○ Contrast induced nephropathy presents with a greater than 50% (or 0.5 increase) in creatinine from baseline that occurs within 48 to 72 hours post-procedure ○ Patients with chronic kidney disease or diabetes are at 4x greater risk for developing contrast induced nephropathy ○ If a patient is taking metformin, it must be stopped for 48 hours post contrast to prevent build up of the medication leading to lactic acidosis ○ A patient does not need any risk factors to have a contrast induced nephropathy ○ Symptoms include fatigue, peripheral edema, pruritus with lab changes of Cr increase >0.5 from baseline ○ Reversible Nephrogenic systemic fibrosis ○ Nephrogenic systemic fibrosis is defined as the thickening or tightening of the skin in large areas after exposure to gadolinium ○ Nephrogenic systemic fibrosis can occur within hours or years after exposure, but it typically occurs 2-10 weeks after exposure to gadolinium ○ There is no cure for nephrogenic systemic fibrosis and it will likely progressively worsen overtime ○ Symptoms include thick, tight skin, pruritus, papules with no lab changes