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‫مشهد‪ ،‬مالصدرا ‪ ، 11‬پالک ‪1/4‬‬
‫‪www.DSNMC.ir‬‬
‫‪Tel:+98(51) 38411524; +98(51)38472927‬‬
Clinical Applications of
Nuclear Medicine
in
GU Tract
a brief revew
a brief review
V. R. Dabbagh Kakhki, M.D.
Nuclear Medicine Specialist
Associate Professor
DSNMC
Nuclear Medicine Research Center (NMRC; MUMS)
Dynamic Renography : DTPA
Nuclear Medicine
& GU
Renal Cortical
Imaging: DMSA
Direct Radionuclide Cystography (DRC):
VCUG with Radioisotope
Dynamic Renography
Technique:
 Bolus
injection of tracer
 Obtained


serial images
Supine
posterior view
Imaging:
 Perfusion: 1-2 sec/view for 1-2min
 Functional : 30 sec/view for 30 min
Dynamic Renography
Technique:
Imaging:
 Perfusion: 1-2 sec/view for 1-2min
 Functional : 30 sec/view for 30 min
Dynamic Renography
Radiotracers
Glomerular Filtration Tubular Secretion
 99mTc-DTPA >95%
Extraction
20%
99mTc-MAG3 <5%
95%
99mTc-EC
<10%
90%
131I-OIH
20%
80%
40-50%
~100%
DTPA: Diethylenetriaminepentaacetic acid
MAG3:
Mercaptoacetylglycine
EC: ethylenedicysteine
OIH: Orthoiodohipuric acid
Dynamic Renography;
Evaluates:
Clinical applications:
 Renal
Obstructive
nephrouropathy
perfusion
 Renal function,
renal morphology
and size
Reflux uropathy
Renal failure
 GFR
 ERPF
Renal transplant
RVH
DTPA normal
A curve can be generated that represents the perfusion only
Mean counts/second
Renal perfusion time-activity
for Tc-99m DTPA
Renogram
2
3
1
1- Blood flow phase (20- 40 sec) Ao-to-Kid ~ 3”
2- Concentration phase (3-5 min) Tpeak < 5’
3- Excretory(washout) phase
Relative (split) function
DRF (Differential Renal Function)
DTPA normal
DTPA flow + Functional Phases
GFR = 29 ml/’
Creat = 2.0
DRF:
LK= 33%
RK= 67%
Renal artery occlusion
Rt renal infarct
Normal Renogram
Renal Function

Creatinine Clearance:

No accurate due to tubular excretion

Overestimates GFR in chronic renal disease and decreased muscle mass

No measure individual renal function unless catheterization of each kidney

Clearance of DTPA

Plasma-sample : more accurate

Camera-based

Relative uptake: DRF

Normal:50/50 to 56/44

57/43 to 59/41: borderline

60/40: abnormal
Obstructive uropathy

Diuresis renography for



Diagnosis
Assesment of parenchymal damage
Postsurgical evaluation

Anatomical imaging methods rely on demonstrating
the structural abnormalities

Diuretic renography : Very useful :
• evaluate renal function and urodynamics in a single test
• but contributes little to determining etiology.
Obstructive uropathy


There are two protocols in use:

F+20 : demonstrates a diuretic response

F-15 :more decisive in detecting minor degrees of obstruction
If SKGFR<16ml/min only Whitaker test can be done
No Obstruction
F+20
F-15
T1/2 washout
cts
100%
50%
T1/2
min
Quantitative t1/2 diuretic response clearance
 Washout
half time

<10 min
No obstruction

Between 10 and 20 min
Indeterminate

>20 min
Urinary obstruction
Diuretic Renal Scan
Indications

Evaluate functional significance of hydronephrosis

Determine need for surgery


obstructive hydronephrosis - surgical Rx

non-obstructive hydronephrosis - medical Rx
Monitor effect of therapy
Diuretic Renal Scan
Requirements
 Rapidly
 Well
cleared tracer
hydrated patient
 Good
renal function
pre-Lasix
post-Lasix
No Obstruction
Lt hydronephrosis
3-wk old baby
3164897
Lt UPJ obstruction
3164897
Lt UPJ obstruction
3164897
Diuretic Renal Scan
Interpretation
 Interpret
 Visual
(dynamic images)
 Washout

T1/2
whole study, not T1/2 alone
curve shape
Diuretic Renal Scan
Pitfalls
 False




Distended bladder
Gross hydronephrosis
Poorly functioning / immature kidney
Dehydration
 False


positive for obstruction
negative
Low grade obstruction
Poorly functioning / immature kidney
Effect of catheterization (1)
full bladder,
no catheter
Effect of catheterization (2)
with catheter
in bladder
Whitaker test
 Standard
for obstruction
 Invasive
 Infusion



:
pressure> 22 cm H2O to achieve a
pelvoureteral flow rate of 10 ml/min : Obs
Indeterminate
<15cm H2O : No Obs
Renal transplant scan;
 Essential
part of transplant department.
 Best tracer: 99mTc-MAG3.
 Perfusion and function analysis
 Useful
in DDx of transplant complications:
ATN, Rejection, Cyclosporine toxicity,
Obstructive disease,Urinoma, Lymphocele,…
Complications after renal
transplantation




ATN
Minutes to hours
Rejection
 Hyperacute
Minutes to hours
 Accelerated
1-5 days
 Acute
After 5 days (first 3 months)
 Chronic
Months to years
Cyclosporine toxicity
Months
Surgical
 Urine leak, Hematoma, Wound infection,
 Obstruction, Lymphocele, RAS
Differential diagnosis of various
complications
Requires correlation of scintigraphic findings
with Pt’s clinical course , physical findings,
laboratory values, current therapy, prior
scintigraphic findings, and results of other
imaging tests.
 Since
many of the complications are
diagnosed from the patterns of changes in
time, it is important to obtain a baseline
study soon after transplantation. Follow-up
studies should be performed always by the
same technique.
Renal transplant scan: TRS

Two Aspects:



Perfusion phase
Function Phase
Choice; Tc99m-MAG3


Good quality perfusion images
High extraction rate
• Excellent images

Evaluation of collecting system, ureter and bladder
TRS: Perfusion
 Images
 Curves
TRS: Functional Phase
 Images
 Curves



Uptake: Tc99m-MAG3: Max: before : 5 min
Parenchymal transit
Excretion of the tracer
Nuclear medicine testing

Obtain a baseline study soon after transplantation
 ATN: Perfusion is better than function, decreased uptake,
delayed transit, diminished clearance
 AR: Decreased perfusion, tracer uptake, delayed transit and
decreased clearance
 CR: low uptake, normal parenchymal transit with absent or
minimal cortical retention
 Cyc toxicity:
 Mild : like CR
 Severe: like ATN
 RVH caused by RAS can not differentiated from CR unless
challenged by ACEIs. ( pattern of CR changes to a pattern of
AR)
Acute rejection
Functional phase
Perfusion Phase
Surgical complications
 US
and Tc99m-MAG3 images
 Diuretic
renography : Differentiate obstruction
from simple pelvocalyceal dilatation
Lymphocele
Urinary Leak
Radionuclide
Cystogram
Indications
 Evaluation

of children with recurrent UTI
30-50% have VUR
 F/U
after initial VCUG
 Assess
effect of therapy / surgery
 Screening
of siblings of reflux pts.
Methods
Direct

Tc-99m S.C. or
TcO4
Advant. via Foley

can do at any age
Disadv. VUR during filling

catheterization
Indirect

Tc-99m DTPA or
Tc-99m MAG3
 i.v.

no catheter
 info on kidneys

need pt
cooperation
 need good renal
fct
Direct Cystography
1
mCi S.C. in saline via Foley
 Fill bladder until reversal of flow

(bladder capacity = (age+2) x 30
 Continuous
imaging during filling &
voiding
 Post void image
 Record



volume instilled
volume voided
pre- and post- void cts
RN Cystogram vs. VCUG
Advantages

Lower radiation
dose
(5 vs 300 mrad to
ovary)
 Smaller amount of
reflux detectable
 Quantitation of
post-void residual
volume
Disadvantages

Cannot detect distal
ureteral reflux
 No anatomic detail
 Grading difficult
Normal cystogram
filling
voiding
post-void
VUR - filling phase
A
VUR - voiding phase & post-
void
B
Post void residual volume
voided vol x post-void cts
RV =
pre-void cts - post void cts
Reflux nephropathy
16%
84%
Vesicoureteral reflux

Conventional method : X-ray micturating cystography
 Excellent delination of bladder and urethral anatomy
 Grading of the reflux
 An alternative method : radionuclide cystography
 Technique:



Direct & Indirect
Direct: The same as radiological VCUG
Indirect: At the end of DTPA or MAG3 renal scan, lesser
sensitivity, no for initial screening test, a positive study is
reliable but a negative study should be confirmed by direct
cystography
Radionuclide cystography:

Advantages:




High sensitivity.
Low radiation.(50 to 200 times less radiation to
gonads comapred to the contrast cystography
Quantification ( post voiding residue).
Disadvantages:


Poor grading ability.
No anatomic detail of the urerthra
* VCUG is reserved for the initial work up of male
patients to exclude an anatomical abnormality,
such as PUV.
Radionuclide cystography:
Indications:

Initial screening to detect reflux in girls with UTI
 Follow up of patients with reflux.
 Screening of siblings
 Serial evaluation of children with neuropathic bladder who
are at risk to develop reflux
Renal infection
 Radiopharmaceuticals:

99mTc-DMSA

99mTc-glucoheptonate

67Ga

111In-WBC
or 99mTc-WBC
Renal sonography





Commonly used in the evaluation and management of
UTI
Non-invasive imaging
Detection of hydronephrosis, and congenital
anomalies
Detection of renal abscesses, pyeonephrosis and
abnormalities of the perinephric space
Changes secondary to acute pyelonephritis may also
be recognized
Cortical imaging:
99mTc-DMSA

Cortical agent
 Trapped in the cytoplasm of the proximal tubular cells
 An indicator of functioning tubular renal mass.
 Advantages : (over IVP and US)
 Pyelonephritis and renal scars: more sensitive
• Tc99m-DMSA : 94%
• Intravenous pyelography :76%
• US: 65%
 Defects on DMSA scan become apparent before on IVP or US
 Lower radiation dose (as compared to the IVP)
 Is not affected by overlying bowel gas or bones
 Avoids possible allergic reaction
DMSA Renal scan;
Clinical applications;










Renal size, shape and location
Renal cortical assessment.
Determining DRF (most accurate noninvasive method)
Infectious disease and distinguish upper from lower UTI(Early
detection and follow up of pyelonephritis; most sensitive,95% Vs
76%)
Follow up of patients(serial scans)
Congenital renal anomaly(Ectopia,..)
Vascular lesions (infarct)
DDx of pseudomass from SOL.
Renal trauma
Confirm the total absence of function in dysplastic kidney
Acute pyelonephritis in DMSA scan
 Single
or multiple areas of decreased cortical
uptake
 No loss of volume
 Diffusely decreased uptake in an enlarged
kidney
Diminished uptake may be due to both focal
tubular cell dysfunction and ischemia

A mature cortical scar is usually associated with
contraction, cortical thinning, loss of volume and
marked reduction in uptake
Normal
DMSA Renal
Scan
Evaluation of Renal
Infection
Renal Morphology Scan
(Renal Cortical
Scintigraphy)
UTI
 VUR

risk factor for PN,

not all pts w PN have VUR
 PN

may lead to scarring >>> ESRD, HTN
early Dx and Rx necessary
 Clinical
& laboratory Dx of renal involvement
in UTI unreliable
Renal Cortical Scintigraphy
Indications
 Determine
involvement of upper tract
(kidney) in acute UTI (acute pyelonephritis)
 Detect
cortical scarring (chronic pyelonephr.)
 Follow-up
post Rx
Renal Cortical Scintigraphy
Procedure
 Tracers


Tc-99m DMSA
Tc-99m GHA
 Acquisition



2-4 hrs post-injection
parallel hole posterior
pinhole post. + post. oblique (or SPECT)
 Processing:
relative fct
Renal Cortical Scintigraphy
Interpretation
 Acute




PN
single or multiple “cold” defects
renal contour not distorted
diffuse decreased uptake
diffusely enlarged kidney or focal bulging
 Chronic


PN
volume loss, cortical thinning
defects with sharp edges
 Differentiation
of AcPN vs. ChPN unreliable
Renal Cortical Scintigraphy
“Cold Defect “
 Acute
or chronic PN
 Hydronephrosis
 Cyst
 Tumors
 Trauma (contusion, laceration, rupture,
hematoma)
 Infarct
DMSA
Normal
Normal DMSA
pinhole
LPO
RPO
Acute pyelonephritis
DMSA
Defect in
Right Kidney
post L
post R
LEAP
LPO
RPO
Renal Cortical Scintigraphy
Congenital Anomalies
 Agenesis
 Ectopy
 Fusion (horseshoe, crossed fused ectopia)
 Polycystic
kidney
 Multicystic
dysplastic kidney
 Pseudomasses (fetal lobulation, hypertrophic
column of Bertin)
DMSA
horseshoe kidney
DMSA
LK Agenesis
Crossed ectopia
74%
26%
Scrotal scintigraphy;








If the diagnosis of testicular torsion is established : surgery
When the diagnosis is uncertain, imaging studies should be
rapidly obtained
Tracer: Technetium pertechnetate (99mTcO4)
Easy, simple and takes only 10 minutes
DDx of acute torsion from other complications
( epididymitis)
Scintigraphy can confirm the clinically suspected diagnosis of
torsion and direct the patient to surgery
Scintigraphy can minimize unnecessary exploration in patients
with an inflammatory cause of their pain.
For chronic or painless disorders of the scrotum US is the
method of choice.
Acute testicular torsion
Scintigraphic findings



The findings depend on the time
 Early torsion: Decreased activity in the region of the
involved testicle
 Late torsion: Increased scrotal activity but relatively
decreased activity in the region of the ischemic testicle “
bull’s eye”
Acute epididymitis & epididymoorchitis:
Increased activity
Scrotal scintigraphy is not the imaging of choice in most
other conditions affecting the scrotal contents.
Scrotal scintigraphy;
 SS


for acute testicular torsion
Sensitivity and specificity > 95%
False negative
• Spontaneous detorsion
• Incomplete twists
• Inguinal testis
Normal
Early torsion
Late Torsion
Renovascular Hypertension

Defined as stenotic lesions of the renal arteries that induce
elevated BP and potentially improve after revascularization
 Anatomic stenosis is not equivalent to the diagnosis of RVH
 Significant morbidity from renal artery angioplasty or
revascularization
 A functional diagnosis is needed before proceeding with therapy
 Discrepancies between scintigraphy and angiography
 Involving the small vessels
 RAS incidentally in a substantial proportion of elderly Pts
 The prevalence of RVH<1%
Captopril Renal Scan
(ACE inhibition renography)
Techniques:
 Post Captopril scan ( 50mg orally,..)
 Base line scan
 Positive if GFR or Curve
worsening
Mechanism:
 Inhibition of ACE, releasing
efferent arteriole constriction.
Advantages:
 Best screening test for RVH
 Best predictor of response to surgery,
angioplasty and captopril therapy
 Determine which Pts have hemodynamically
significant stenoses enough to cause HTN
 Avoided unnecessary arteriograms
 Detection of RVH whatever the level of
arterial obstruction
 High accuracy
 Sensitivity: 80-90%
 Specificity:90-95%
Criteria of positivity
 10%
rise in cortical retention ratio
 Increase in the Time to peak
 Worsening in DRF ( relative uptake)
 MPTT
Criteria of positivity

Shape of curve: a worsening of at least one grade
Baseline Study
Post-captopril Study
Pre- and post captopril excretion curves of the right kideny
Selection of patients for evaluation

Diagnosis of RVH can be made only after the patient
responds to revascularization

The tests can not be used as a mass screening procedure:

The incidence of RVH is low and therefore post test probability
of a positive test still has a low probability of RVH.

CRS appears to have improved sensitivity and specificity to the
point where it is practical to screen selected patients.
Indication of ACE inhibition renography


Accelerated or malignant HTN
Abrupt or recent onset HTN
 Onset under age 30 or over age 55
 Refractory HTN
 Abdominal or flank bruits
 Unexplained azotemia
 Worsening renal function during therapy with ACEIs
 End organ damage ( LVH, retinopathy)
 Occlusive disease in other vascular beds
 Previous hypertensive urogram suggestive of RAS
 Unilateral small kidney
Aspirin Renography
Renal blood flow
PGE2
Renin


-
Inhibition of PG synthesis would decrease renin : An effect similar
to captopril
Aspirin reduces both renal blood flow and glomerular filtration
Similar sensitivities to ACEI scintigraphy
V.R.Dabbagh; DSNMC;
www.DSNMC.ir