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3- Anatomic Imaging and Nuclear Medicine (Renal System)

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omarys's version from 2017-05-23 20:30

Section 1

Question Answer
The renal corpuscles are found only within thecortex
The upper pole of the kidney is more ____ and ____posterior ; medial
Which kidney is larger in diameter?Lt. (up to 2cm difference)
T or F- the kidneys are very mobile.True. Up to 6cm displacement.
The renal sinus appears ___ (color?) in H&E due to its ____ contentwhite ; fat
T or F- the apex of the pyramid is the calyx.False. The apex of the pyramid = papilla. The papillae drain into calyces.
What is the missing structure? Calyces >> ____ >> pelvisinfundibulae
Are there anastomoses bwn the segmental arteries?No. If a segmental artery is blocked or damaged, its segment will necessarily become ischemic (unless there's an accessory artery ofc).
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Section 2

Question Answer
In imaging, the _________ phase and the venous drainage occur simultaneously.corticomedullary phase
When injecting dye/contrast media, if both the cortex and the medulla show enhancement, this is termed-nephrographic phase
The cortex is visualized in the corticomedullary phase because the contrast material is within the ______ ____blood vessels
The medulla is enhanced in the nephrographic phase because the contrast material has moved from the _____ _____ to the ______ system.blood vessels ; collecting system (contrast material has been filtered)
RCC is a very _____ tumor, and will be maximally enhanced during the ______ phase.vascular ; corticomedullary
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Section 3

Question Answer
Contrast media used in CT?Iodide (intravenous/extra-cellular)
In the first stage of multi-phasic imaging, an _____ _____ is performed to show location of kidneys, stones, etc.unenhanced CT (=template)
It's better NOT to use contrast material when-suspecting stones (both stones + contrast material are hyperdense, so the contrast material will actually 'mask' the stone)
EVEN WITHOUT CONTRAST MATERIAL (check this), RCC will show an enhancement of over _____ (#) ____ (units)20 HU
A pathology is diagnosed when there is a > ___ ____ change from baseline (before and after contrast material injection)12 HU
There is a significant _____ in the ____ _____ to the kidneysvariation ; blood supply
In about _________% of the population there is a unilateral _____ _____.30 ; accessory artery
Which kidney is preferable for transplant?The left kidney, because the left renal vein (longer) can be manipulated more easily.
Which are more anterior, the renal arteries or veins?The veins
The left renal vein drains (1 organ & 3 other veins)-The kidney, the lt. adrenal, gonadal and lumbar veins (The lt. renal vein is 6-10cm long; makes sense that it drains so many structures compared to the rt.)
Possible variations of the (lt.) renal vein are a ___-aortic or ___-aortic renal veincircum ; retro
Which is a more common variation, circumaortic lt. renal vein or retroaortic renal vein?Circumaortic (17% vs 3%)
a lt. renal vein anomaly where an ACCESSORY lt. renal vein passes posterior to the aorta, APART FROM THE NORMAL RENAL VEIN passing anteriorly (i.e. it looks like a collar around the aorta)circumaortic lt. renal vein
T or F- a circumaortic lt. renal vein is no biggie and can be ignored.False. This anomaly is potentially hazardous, if unrecognized during retroperitoneal surgery.
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Section 4

Question Answer
Hiyo
Renal cortex is enhanced but medulla is notcorticomedullary phase
It's the first phase of contrast enhancementcorticomedullary phase
It happens a very short period (25-70 sec) after contrast medium injectioncorticomedullary phase
An example of a false negative result in the CM phase is whena centrally located tumor is mistaken for normal hypoattenuating medulla
An example of a false positive result in the CM phase is whenthe heterogeneously (=partially) enhancing medulla may be mistaken for a solid tumor
The limitations of the corticomedullary phase show it is not sufficient in the case of _____tumors
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Section 5

Question Answer
Homogeneous enhancement of renal parenchyma occurs in the _______ phasenephrogaphic (but the pelvis is not enhanced yet! homogenous = cortex + medulla only)
Occurs up to 3 mins after contrast medium injectionnephrographic phase (80-180 sec post injection)
Renal masses enhance maximally during the _____ _____, which is what makes it ideal for detection of tumors/local lesions.nephrographic phase (recall that the corticomedullary phase is not ideal for tumors)
When the contrast medium is found ONLY in the collecting system (e.g. calyces, pelvis, even as distal as bladder)excretory phase
Begins AFTER 3 mins of contrast medium injectionexcretory phase
The most common tumor in the collecting system istransitional cell carcinoma
The most common tumor in the kidney itself isRCC
A fungus ball, clot or other mass in the collecting system is best visualized in theexcretory phase
The excretory phase is useful for characterization of _________ (what condition?) and for differentiating it from para-pelvic cystshydronephrosis (cysts don't fill with contrast material while HN does)
15:15 rule- If 15 mins post injection, there is a >15 HU DECREASE in enhancement (relative to corticomedullary phase), we know there's ahyperdense lesion/mass
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Section 6

Question Answer
Plain abdominal film (conventional radiology) is used to tell if _____ are presentcalcifications/stones
in an x-ray, normal kidney size would be equal to the size of around ___ (#) vertebrae3.5
a form of imaging of the renal PELVIS and URETERSpyelogram
an x-ray examination of the kidneys, ureters and urinary bladder that uses iodinated contrast material injected into veinsIVP (intravenous pyelogram)
useful for finding stones along urinary system, for determining if there's hydronephrosis, for general evaluation of the structure of the urinary tractIVP
In addition to stones, hydronephrosis, normal anatomy, what can IVP show? (3)tumors along UT, cause of recurring UTI, general damage to UT after injury
How-to IVP: inject contrast material, wait for ___ phase, i.e. check after _________ mins of injectionexcretory ; 10
The IVP method uses a ___ of ____, and is not very ____, so its use today is ____.lot of radiation ; informative ; declining
What tissue is white/hyperechogenic in US?fat
Audible sound is within this range of frequencies:20 Hz - 20,000 Hz
Diagnostic US uses this range of frequencies:1-20 MHz (1,000,000-20,000,000 Hz)
Using US for GUS is usually in ____ and _____ ____, due to its lack of radiation.children ; pregnant women
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Section 7

Question Answer
US of the GUS is used to detect/visualize (4)kidney size and location ; hydronephrosis ; stone diseases (in kidney & bladder, not ureters!) ; renal masses
2 most common causes of hydronephrosisstones ; tumors
Hematuria is characteristic of ___-induced hydronephrosisstone and tumor (both)
Painless hematuria is characteristic of ____. The opposite is true regarding stones.tumors
In US, the renal cortex appears ___ (color?)black
In US, the "central complex" (renal pelvis mainly) appears ___ (color?)white/hyperechogenic (fat content)
Besides masses/stones/kidney size and location, what is US of the GUS useful for? (3)evaluation of: bladder volume ; bladder+collecting system pathologies ; arterial+venous anatomy & pathology
What is US of the GUS NOT good at?ureters
When observing stones/calcifications, the modality of choice will NOT be-MRI
1 tesla = ____ gauss10,000
a unit of measurement of the strength of a magnetic fieldtesla (also: gauss)
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Section 8

Question Answer
Strength of Earth's magnetic field measures0.5×10−4 tesla (0.5 gauss)
MRI magnet strength10,000 gauss (1 tesla) = 20,000 times the strength of Earth's magnet
CT/MRI of the GUS useful forstones (only CT), masses, collecting system+bladder pathologies, arterial and venous pathologies (MRA and CTA), general injuries to the GUT (CT preferably)
MRI advantages in GUS imaging (4)no radiation, detects small (<3cm) renal masses, detects cystic/indeterminate lesions better than CT (better contrast), no nephrotoxicity from or allergy to contrast material
FLUID appears white in which MRI weighing, T1 or T2?T2 (mnemonic- WW2 = Water White 2)
In a T2-weighted image, the renal pelvis should appear-white (contains urine)
Fat saturation/attenuation is good because itenhances the contrast
Generally, to check for stones in GUS, first we use ____, then ____ for better resolution, but not ____.US > CT ; MRI
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Section 9 (nuclear medicine)

Question Answer
Nuclear medicine usually depends on kidney ___, so in diseases like multicystic kidney we won't get anythingfunction
Technetium radiopharmaceuticals used in renal (dynamic) mappingTc-99m MAG3 and Tc-99m DTPA
Considered advantageous in paediatric patients and patients with poor renal function due to its TUBULAR SECRETION (rather than glomerual filtration)Tc-99m MAG3
target organ is usually bladderMAG3
uptake by PROXIMAL TUBULE cellsMAG3
MORE plasma is cleared from this substance per unit time (therefore its concentration in the kidney is higher than an equivalent dose of the other substance)MAG3 (higher clearance)
"blood flow phase" of mappingwhen the Tc-99m is still in the renal vessels so it reflects blood flow to the kidney
"parenchymal phase" of mappingwhen the substance is in the cortex, either in the glomeruli/corpuscles (DTPA) or the proximal tubule cells (MAG3)
"excretion phase" of mappingwhen the substance is within the ureters and bladder
radioactivity in kidney vs. time =radioactive renogram
regions of interest =done as part of the renogram
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Section 9.5

Question Answer
Renal plasma flow =600 ml/min (recall that both kidneys receive 25% of CO i.e. 1.25 L/min, so half of that would be around 600 ml/min)
GFR =120 ml/min (20% of RPF)
Tubular secretion rate =480 ml/min
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Section 10

Question Answer
Relative functioning of a kidney =(radioactivity of kidney #1 during PARENCHYMAL PHASE) / (total radioactivity of both kidneys during same phase)
T or F- a "relative kidney functioning" test will show how the kidneys function compared to one another (e.g. 50%-50% or 30%-70%), as well as general (absolute) kidney function.False. Only the first part is true. Relative kidney functioning shows exactly what its name implies: the RELATIVE (not absolute) function of each kidney.
Can a person with kidney failure have a 50% result (=normal result) in a relative kidney functioning test?Yes.
Diuretic kidney mappinguse of fusid (furosemide) to check for obstruction (esp' in UPJ)
Fusid is used in diuretic mapping to differentiate betweenfluid collection (in pelvis) due to obstruction (=hydronephrosis) vs. fluid collection due to patient being in supine position (in the latter- fusid will cause the fluid to move to the ureters and bladder)
In nuclear imaging, how do you know the rate of urine drainage from the kidneys?Measure T1/2 of the radioactivity
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Section 11

Question Answer
Most common congenital malformation of the UT ishydronephrosis
Hydronephrosis can be ____ as well as ____acquired ; congenital
Hydronephrosis/hydroureter can be ____ or non-____obstructive
Vesicoureteric reflux (VUR) can lead tohydroureter / hydronephrosis
abdominal muscle deficiency syndrome (congenital absence of the abdominal muscles) is AKAPrune belly syndrome
Urinary tract abnormality such as unusually large ureters, distended bladder, and vesicoureteral reflux are characteristic ofprune belly syndrome (it's one of the prune-belly triad)
Complications of hydronephrosis (or other dilatation pathology)-infections ; damage to kidney parenchyma (due to increased pressure in kidneys)
Obstruction of the ___ (which happens spontaneously during pregnancy) is the most common cause of congenital (obstructive) hydronephrosis.UPJ
Fixing a congenital UPJ obstruction surgically is only necessary in _________% of cases.20 (majority of congenital UPJ obstruction resolve spontaneously)
What is a necessary step/test for determining whether a UPJ obstruction requires pyeloplasty or will resolve spontaneously?Relative kidney functioning
Indications for pyeloplasty when there's a congenital UPJ obstruction areimpaired relative function of a kidney ; DECLINE in relative function in consecutive tests ; clinical symptoms (infection, pain) ; progressive deterioration in pelvis dimensions in consecutive US tests
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Section 12

Question Answer
So all in all, dynamic mapping of kidneys is useful fordetermining whether there is an obstruction + determining relative kidney function
Cause of bilateral hydroureteronephrosisposterior URETHRAL valve (developmental anomaly)
A non-obstructive cause of hydrouretervesicoureteral reflux (VUR)
Dynamic mapping W/ FUSID can help differentiate betweenobstructive and non-obstructive hydroureter (in the latter, radioactive substance will be drained to bladder)
Dynamic mapping W/ CAPTOPRIL is used to evaluatehypertension (secondary to renal artery stenosis)
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Section 13: Static renal mapping

Question Answer
Static mapping of kidneysinjection Tc-99m DMSA >> uptake of substance into PROXIMAL TUBULE cells (same as MAG3) >> NO secretion of substance into lumen
Static mapping shows the ____ of the kidneycortex
Imaging is done 3-4 ____ after injectionHOURS
Use DMSA for diagnosis ofacute pyelonephritis, scarring of kidneys, ectopic kidneys, dysplasia in kidneys,
Also possible to do in DMSA (same as in dynamic mapping)relative kidney functioning
It is the gold standard for dx of pyelonephritis and scarring of kidneysDMSA
In a normal DMSA mapping, there is a _____ _____ of the radioactive substance throughout the ____.homogeneous distribution ; cortex
If there's a scar, a DMSA mapping will show awedge shaped "filling/uptake defect" (with its base being towards the periphery)
A more common form of DMSAlate DMSA (6 months post-infection)
it checks for scarringlate DMSA (takes time for scar from pyelonephritis to develop)
UTI with kidney involvement are common especially inchildren
After a child has been dx-ed with UTI for the first time, we use ___ to see if there's a susceptibility to further infections.US (check for stasis/dilatations, anomalies, etc.)
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Section 14

Question Answer
A ____ kidney is more susceptible to infections.dysplastic
Dysplastic kidney(congenital) abnormality in development of kidney- will show heterogeneous distribution of DMSA (shape of defect not as "neat"/specific as in scarring)
To prevent infections, a dysplastic kidney with less than ___% relative function can be removed.10
In acute pyelonephritis, using acute DMSA will show-focal uptake defects (overall kidney contour will look fine)
If the patient heals from the pyelonephritis, DMSA will show normal (homogeneous) uptake/distribution of DMSA after a few _____.months
DMSA is able to show what congenital malformations (other than dysplasia) of the kidneys?Ectopic kidneys (if functional), horseshoe kidney, crossed fused ectopy (it shows these conditions better than US)
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