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USE OF NUCLEAR IMAGING
IN KIDNEY DISEASES :
INDICATIONS AND
INTERPRETATIONS

20-5-13
Isotopes







Any given element may have many isotopes
All isotopes of a given element have the same no of
protons a...
Radionuclides






Photon Emitting(imaging) – Tc99m;
Mo99;I123;Ga67;In113;Kr81;Th201
Positron Emitting(imaging) C11;N1...
Radionuclides for Imaging
Desirable characteristics
Minimum particulate emission
Primary photon energy between 50-500 keV
...
Technetium

99m








Fulfills many criteria of ideal radionuclide
No particulate emission
6 hour half life
A predo...


Nuclear medicine is a branch of  medicine 
and imaging that uses radionuclides and relies on
the process of radioactive...


Functional and anatomic information



More organ / tissue specific c/t whole body scans



RADIOPHARMACEUTICALS =
RA...
NUCLEAR SCINTIGRAPHY
TECHNIQUES
 2D Scintigraphy  - use of internal radionuclides to create twodimensional images.


3D ...
TOPICS


Renal Scintigraphy



ACEI renal scan



Renal Transplant Scintigraphy



Radionuclide cystogram
Renal scintigraphy

INDICATIONS








Renal perfusion and function
Urinary Tract Obstruction (Furosemide renal sc...
Radiopharmaceutical Agents
1.

Grouped into three categories:
Those excreted by glomerular filtration,

1.

Those excreted...
Radiopharmaceutical Agents
Glomerular Agents



Tc 99m DTPA
Cr-EDTA

51

I 125 Iothalamate
Glomerular Filtrating Agents
Tc-99m DTPA
(Diethylenetriamine pentaacetic acid)
COOH
COOH
N
HOOC

N
N
COOH
COOH
Tc 99m DTPA
•

•

•

Inulin clearance remains the gold standard to
measure GFR, but it is expensive, time
consuming, and r...
•
•
•

•

Peak renal activity after 3 – 4 min.
90 % filtered within 4 hours.
The extraction fraction of 99mTc-DTPA is
appr...
 51Cr-EDTA, which may provide more accurate

values for GFR, but cannot be used for
imaging.
Tubular secreting agents:




I131/I123 OIH
Tc99m MAG3
Tc99m EC

Proximal convoluted
tubules




p-Aminohippuric acid (PAH) is the gold
standard for the measurement of ERPF.
However, it is not well suited for rout...
I-131/I-123
Orthoiodohippurate
O
-C-NH-CH2-COOH
I

Chemical structure similar to the Paraaminohippuric acid
I-131 OIH
Secreted by tubules – 80% & glomerular
filtration - 20%
Chemically & pharmacokinetically similar to
PAH
Plasma p...




The main disadvantages of 131I-OIH are the
suboptimal imaging characteristics of 131I.
123
I-OIH has better imaging ...
Tc99m MAG3
(Mercaptoacetyl triglycine)
CH2-COO

S

O

N

Tc
O

N

N
O
Tc99m MAG3








70 – 90 % PROTEIN BINDING
89% TUBULAR SECRETION
11% GLOMERULAR FILTRATION
Extraction fraction of ...
Tc99m L,L-EC
(Ethylene dicysteine)
N

N

-ooc

cooTc
S

S

Exists in 4 different forms D,D-EC; L,L-EC; D,L-EC & L,D-EC
EC:







Metabolite of the L,L-ECD(ethylene cystine
dimer) with cortical uptake
Secretion in proximal convoluted tu...
Cortical Binding Agents:


Tc99m DMSA



Tc99m GHA
Tc-99m DMSA
(Dimercaptosuccinic Acid)
H
HS

COOH

HS

COOH
H
Cortical agents
Tc99m DMSAPYELONEPHRITIS, INFARCTS, SCARS, ANOMALIES










75% protien binding in 6 hrs
5- 20 ...


Importantly, acute infection can produce
abnormalities in the scan; and if the test is being
performed to evaluate for ...
Tc 99m GHA
(Glucoheptonate)
O

O

O

C

O
Tc

CH

O
(CHOH)4
CH2OH

O
C

O

CH
(CHOH)4
CH2OH
CONTD..








Tc 99m GH
It is both filtered by the glomerulus and bound by
the tubules.
Glomerular filtration 80-...
Choosing Renal Radiotracers
Clin. Question
Perfusion
Morphology
Obstruction
GFR quantitation
ERPF quantitation

Agent
MAG3...
Basic Renal Scan

Procedure
Basic Renal Scintigraphy

Patient Preparation


Patient must be well hydrated
Give 5-10 ml/kg water (2-4 cups)
30-60 min....
Basic Renal Scintigraphy

Acquisition


Supine position preferred



Flow (angiogram) : 2-3 sec / fr x 1 min



Dynamic...
Basic Renal Scintigraphy

Acquisition (cont’d)


Obtain a 30-60 sec. image over injection site @
end of study




if in...
International Consensus Committee
Recommendations for Basic Renogram



Tracer: MAG3, (DTPA)




Dose: 2 - 5 mCi adult,...
Radionuclide Renal Evaluation








Functional Imaging(visual assessment of
perfusion and function)
Renography (time...
Functional Imaging







Perfusion imaging –
Evaluation of renal blood flow and function of
native kidneys – posteri...


In normal renal blood flow
By 3 sec aorta is fully visualized.
By 5-6 sec, both kidneys are seen.
Maximal kidney activi...
DTPA normal
Renal functional imaging





At the end of perfusion sequence , imaging for
function begins.
Dynamic or sequential sta...


With Tc99m MAG3 maximal parenchymal activity
is seen at 3-5 min



Activity in collecting system and bladder by 4-8
mi...
DTPA normal
Renography


A Time Activity Curve



Graphic representation of uptake and excretion
of radiopharmaceutical



Informat...
Renogram Phases


FLOW / VASCULAR PHASE



( 30 MIN )

(RADIONUCLETIDE
ANGIOGRAM)
•
•

FUNCTIONAL PHASE

II.

Parenchyma...
RENOGRAM PHASES
Data obtained from renogram


Time to peak cortical activity- 3-5 min



Half-time excretion- time for half of peak
acti...
RELATIVE/SPLIT
FUNCTION


Contribution of each kidney to the total function
% Lt kid =

net cts in Lt ROI
---------------...
Relative (split) function
ROI’s
Quantitation of Renal Function
GFR & ERPF measurement
 Two methods :
Plasma sample based clearances :
 The amt of activi...





Camera based clearances :
Counts are obtained from syringe before inj. &
subsequently over kidneys after injection...
Anatomic(Cortical) Imaging
(Tc99m DMSA or GH )




Images obtained after 2 to 4 hrs of injection
Posterior/ right post....
Diuretic (Furosemide) Renal Scan


Obstructive uropathy (hydronephrosis, hydroureter)
may lead to obstructive nephropathy...
PRINCIPLE


Hydronephrosis - tracer pooling in dilated renal
pelvis



Furesemide induces increased urine flow



If ob...
PROTOCOL






Oral hydration prior to study
NS @ 15ml/kg over 30 min 15 min prior to
injection & continued in study ...
PROTOCOL








Pre requisite – residual function to respond
Diuretic given ( infants- 1mg/kg, children 0.5
mg/kg, 4...
Diuretic Renal Scan

Washout
(diuretic response)
T1/2
time required for 50% tracer to leave
the dilated unit
i.e. time req...
T1/2






Normal
< 10 min
Obstructed
> 20 min
Indeterminate 10 - 20 min
Best to obtain own normals for each instituti...
Scintigraphic evaluation of
Hydronephrosis

Showing non-obstructive hydronephrosis of the left kidney,
The arrow indicatin...
Scintigraphic evaluation of
Hydronephrosis

Showing obstructive hydronephrosis of the right kidney,
The arrow indicating a...
“F minus 15” Diuretic
Renogram


Furosemide (Lasix) injected 15 min before
radiopharmaceutical



Rationale: kidney in m...
Evaluation of Renovascular
Hypertension

Captopril Renal Scan
(ACEI Renography)
Captopril Renal Scan
(ACEI Renography)
Renovascular Disease


Renal artery stenosis (RAS)



Ischemic nephropathy



Re...
Renin-Angiotensin System
RAS
Angiotensinogen
Renin
Angiotensin I

Captopril

ACE
Angiotensin II
Aldosterone

Vasoconstrict...
Effect of RAS on GFR
Renovascular Hypertension


Prevalence




<1% unselected population with HTN

Clinical features


Abrupt onset HTN in...
Diagnosis of RAS


Gold standard: angiography



Initial non-invasive tests:





ACEI renography
Duplex sonography

...
Captopril Renal ScanMAG 3


Tc 99m MAG 3 = gold standard



Stop ACE inhibitors 48 hrs prior and no solid food
before 4 ...


Protocol:

1 day vs. 2 day test



1 day test:

baseline scan (1-2 mCi) followed by
post-Capto scan (8-10 mCi)



2 d...
Abnormal captopril Renography









Delayed time to maximal activity >11
minutes(normal -5min)
Significant asymmet...
Captopril Renal ScanMAG 3
MAG3 RENOGRAM

CAPTOPRIL RENOGRAM
TIME/ACTIVITY CURVE
AFTER 48 HOURS
MAG3 RENOGRAM

CAPTOPRIL RENOGRAM
TIME/ACTIVITY CURVE
AORTOGRAM
ACEI Renography




In normal renal function - sens/spec ~ 90%
In poor renal function / ischemic nephropathy,
ACEI renog...
Renal Cortical Scintigraphy
Indications


Determine involvement of upper tract
(kidney) in acute UTI (acute pyelonephriti...
CONTD..







gold standard 99mTc DMSA
The radiotracer is taken up only by functioning
PCT mass
Pyelonephritis impair...
Renal Cortical Scintigraphy
Cold Defect
 Acute or chronic PN
 Cyst
 Tumors
 Infarct
 Trauma (contusion, laceration,he...
—2-year-old girl with fever.

Lim R AJR 2009;192:1197-1208

©2009 by American Roentgen Ray Society
Renal Cortical Scintigraphy
Congenital Anomalies
 Agenesis
 Ectopy
 Fusion (horseshoe, crossed fused ectopia)
 Polycys...
NORMAL DMSA SCAN
HORSE SHOE KIDNEY
Horseshoe kidney with normal
function
RENAL AGENESIS
Patient with Recurrent UTI

Tc99m-DMSA renal SPECT
scintigraphy
Ectopic left kidney with multiple
scars
Renal Transplant Evaluation:







Anterior images are obtained.
Normal perfusion study: radioactive bolus
reaches t...
Renal Transplant Scintigraphy

Transplant kidney is showing
good perfusion, uptake and
drainage of radiotracerNormal Study...
POST OP 1 WEEK

POST OP 2 WEEKS


Acute Tubular Necrosis:
Preserved or mildly reduced renal perfusion but
diminished renal function and progressive
corti...
Renal Transplant Scintigraphy

Acute Tubular Necrosis

Acute Rejection

Tc99m-DTPA renal dynamic scintigraphy
Renal Transplant Scintigraphy

Transplant kidney is
showing poor perfusion,
uptake and drainage of
radiotracer- Chronic
Re...
Cyclosporin nephrotoxicity :
 Scintigraphic appearance similar to ATN, with
relative good transplant perfusion and poor
t...
Renal transplants scintigraphy

Surgical complications
Urinary leak-Initial photopenic defect
accumulation of radiotracer
...
Renal Transplant Scintigraphy

10th Post operative day of renal transplant
decreased urine output and pelvic
collection
Ur...
Renal Transplant Scintigraphy

2nd Post operative day of renal transplant
Hematoma / abscess
Renal Transplant Scintigraphy

7th Post operative day of renal transplant c/o
Increased serum creatinine and pelvic collec...
Radionuclide Cystogram
INDICATIONS
 Assess effect of
therapy / surgery
 Screening of siblings of
reflux pts
 Evaluation...
Radionuclide Cystogram
Refrences






Oxford text book of clnilcal nephrology-3rd ed.
Essentials of Nuclear Medicine Imaging –
Mettler & Gui...
Nuclear imaging in  kidney disease
Nuclear imaging in  kidney disease
Nuclear imaging in  kidney disease
Nuclear imaging in  kidney disease
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Nuclear imaging in kidney disease

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Nuclear imaging in kidney disease

  1. 1. USE OF NUCLEAR IMAGING IN KIDNEY DISEASES : INDICATIONS AND INTERPRETATIONS 20-5-13
  2. 2. Isotopes     Any given element may have many isotopes All isotopes of a given element have the same no of protons and differ only in the no of neutrons Some of these isotopes have unstable nuclear configuration and seek greater stability by decay/disintegration to a more stable form Isotopes attempting to reach stability by emitting radiation are called radionuclides/radioisotopes
  3. 3. Radionuclides    Photon Emitting(imaging) – Tc99m; Mo99;I123;Ga67;In113;Kr81;Th201 Positron Emitting(imaging) C11;N13;O15;F18;Rb82 Used for therapy- P32;Sr89;Y90;I131;Sm153
  4. 4. Radionuclides for Imaging Desirable characteristics Minimum particulate emission Primary photon energy between 50-500 keV Physical T1/2 > time reqd to prepare material Effective T1/2 longer than examination time Low toxicity Stability or near stability of the product 
  5. 5. Technetium 99m      Fulfills many criteria of ideal radionuclide No particulate emission 6 hour half life A predominant (98%) 148KeV photon conversion Used in > 70% of nuclear imaging procedures in United States
  6. 6.  Nuclear medicine is a branch of  medicine  and imaging that uses radionuclides and relies on the process of radioactive decay in the diagnosis and treatment of disease.  Used in Nephro-Urology since 1960s
  7. 7.  Functional and anatomic information  More organ / tissue specific c/t whole body scans  RADIOPHARMACEUTICALS = RADIONUCLIDES + PHARMACEUTICAL
  8. 8. NUCLEAR SCINTIGRAPHY TECHNIQUES  2D Scintigraphy  - use of internal radionuclides to create twodimensional images.  3D  SPECT - tomographic technique using gamma camera data from many projections and reconstructed in different planes  HYBRID SCAN - SPECT/CT and PET/CT
  9. 9. TOPICS  Renal Scintigraphy  ACEI renal scan  Renal Transplant Scintigraphy  Radionuclide cystogram
  10. 10. Renal scintigraphy INDICATIONS        Renal perfusion and function Urinary Tract Obstruction (Furosemide renal scan) Reno-vascular HTN (Captopril renal scan) Infection (renal morphology scan) Pre-surgical quantitation (nephrectomy) Renal transplantation Congenital anomalies/masses(renal morphology scan)
  11. 11. Radiopharmaceutical Agents 1. Grouped into three categories: Those excreted by glomerular filtration, 1. Those excreted by tubular secretion, and 2. Those retained in the renal tubules for long periods
  12. 12. Radiopharmaceutical Agents Glomerular Agents  Tc 99m DTPA Cr-EDTA 51 I 125 Iothalamate
  13. 13. Glomerular Filtrating Agents Tc-99m DTPA (Diethylenetriamine pentaacetic acid) COOH COOH N HOOC N N COOH COOH
  14. 14. Tc 99m DTPA • • • Inulin clearance remains the gold standard to measure GFR, but it is expensive, time consuming, and requires a steady-state plasma concentration and accurate and timed urine collection 99m Tc-DTPA is recommended agent is for GFR measurement. 5- 10% plasma protein binding, so it tends to underestimate the GFR(insignificant)
  15. 15. • • • • Peak renal activity after 3 – 4 min. 90 % filtered within 4 hours. The extraction fraction of 99mTc-DTPA is approximately 20 per cent; for this reason, not useful for imaging , in patients with impaired renal function. In such cases, agents with higher extraction efficiencies such as 99mTc-MAG3 more appropriate.
  16. 16.  51Cr-EDTA, which may provide more accurate values for GFR, but cannot be used for imaging.
  17. 17. Tubular secreting agents:    I131/I123 OIH Tc99m MAG3 Tc99m EC Proximal convoluted tubules
  18. 18.   p-Aminohippuric acid (PAH) is the gold standard for the measurement of ERPF. However, it is not well suited for routine studies.
  19. 19. I-131/I-123 Orthoiodohippurate O -C-NH-CH2-COOH I Chemical structure similar to the Paraaminohippuric acid
  20. 20. I-131 OIH Secreted by tubules – 80% & glomerular filtration - 20% Chemically & pharmacokinetically similar to PAH Plasma protein binding – 70% Cortical peak time = 3-5 min Radiation absorbed dose to bladder= 0.74 rad/mCi
  21. 21.   The main disadvantages of 131I-OIH are the suboptimal imaging characteristics of 131I. 123 I-OIH has better imaging qualities, but 123I is more expensive and less available.
  22. 22. Tc99m MAG3 (Mercaptoacetyl triglycine) CH2-COO S O N Tc O N N O
  23. 23. Tc99m MAG3       70 – 90 % PROTEIN BINDING 89% TUBULAR SECRETION 11% GLOMERULAR FILTRATION Extraction fraction of 40-50%. Provides a high target-to-background ratio, good image quality, and more accurate numerical values, particularly when the kidney function is low or immature 5 TO 10 mCi i.v. ( ADULTS)
  24. 24. Tc99m L,L-EC (Ethylene dicysteine) N N -ooc cooTc S S Exists in 4 different forms D,D-EC; L,L-EC; D,L-EC & L,D-EC
  25. 25. EC:      Metabolite of the L,L-ECD(ethylene cystine dimer) with cortical uptake Secretion in proximal convoluted tubules Plasma protein binding is 50% Exact excretion mechanism is not known Clearance is 69-85% of OIH
  26. 26. Cortical Binding Agents:  Tc99m DMSA  Tc99m GHA
  27. 27. Tc-99m DMSA (Dimercaptosuccinic Acid) H HS COOH HS COOH H
  28. 28. Cortical agents Tc99m DMSAPYELONEPHRITIS, INFARCTS, SCARS, ANOMALIES         75% protien binding in 6 hrs 5- 20 % excretion 2 hrs 37% excretion in 24 hrs 40-50% cortical localisation Maximum activity at 3-6 hrs 2 TO 5 mCi i.v. Images at 2 – 4 hrs
  29. 29.  Importantly, acute infection can produce abnormalities in the scan; and if the test is being performed to evaluate for cortical scarring, it should be done at least 3 months after an acute infection ( Rosenberg et al, 1992 ).
  30. 30. Tc 99m GHA (Glucoheptonate) O O O C O Tc CH O (CHOH)4 CH2OH O C O CH (CHOH)4 CH2OH
  31. 31. CONTD..        Tc 99m GH It is both filtered by the glomerulus and bound by the tubules. Glomerular filtration 80-90% Tubular secretion 10-20% 25-40% in 1 hr & 70% in 24 hrs in urine 15% bound to PCT EARLY DYNAMIC FUNCTIONAL imaging DELAYED CORTICAL imaging 10-15 mCi
  32. 32. Choosing Renal Radiotracers Clin. Question Perfusion Morphology Obstruction GFR quantitation ERPF quantitation Agent MAG3, DTPA, GHA DMSA, GHA MAG3, DTPA, OIH I-125 iothalamate, Cr-51 EDTA, DTPA MAG3, OIH
  33. 33. Basic Renal Scan Procedure
  34. 34. Basic Renal Scintigraphy Patient Preparation  Patient must be well hydrated Give 5-10 ml/kg water (2-4 cups) 30-60 min. pre-injection  Can measure U - specific gravity (<1.015)    Void before injection Void @ end of study Int’l Consens. Comm. Semin NM ‘99:146-159
  35. 35. Basic Renal Scintigraphy Acquisition  Supine position preferred  Flow (angiogram) : 2-3 sec / fr x 1 min  Dynamic: 15-30 sec / frame x 20-30 min (display @ 1-3 min/frame)
  36. 36. Basic Renal Scintigraphy Acquisition (cont’d)  Obtain a 30-60 sec. image over injection site @ end of study   if infiltration >0.5% dose do not report clearance Obtain post-void supine image of kidneys @ end of study Taylor, SeminNM 4/99:102-127
  37. 37. International Consensus Committee Recommendations for Basic Renogram  Tracer: MAG3, (DTPA)   Dose: 2 - 5 mCi adult, minimum 0.5 mCi peds Pt. position: supine (motion, depth issues)  Include bladder, heart  Collimator: LEAP  Image over injection site Int’l Consens. Comm. Semin NM ‘99:146-159
  38. 38. Radionuclide Renal Evaluation     Functional Imaging(visual assessment of perfusion and function) Renography (time activity curve representative of renal function) Quantification of renal function(GFR & ERPF) Anatomic imaging( cortical imaging)
  39. 39. Functional Imaging      Perfusion imaging – Evaluation of renal blood flow and function of native kidneys – posterior projection ; transplanted kidneys – anterior projection 10-20mCi of radiopharmaceutical injected iv in antecubital vein. Imaging renal perfusion is usually begun as soon as bolus is seen in abd. Aorta Subsequent images are taken every 1-5 secs
  40. 40.  In normal renal blood flow By 3 sec aorta is fully visualized. By 5-6 sec, both kidneys are seen. Maximal kidney activity is reached in 30-60 sec.
  41. 41. DTPA normal
  42. 42. Renal functional imaging    At the end of perfusion sequence , imaging for function begins. Dynamic or sequential static; 3-5 min Tc99m DTPA or MAG3 are then obtained over 20-30 mins. Evaluation is similar to an IVP with – anatomy, position, symmetry and adequacy of function & collecting system patency.
  43. 43.  With Tc99m MAG3 maximal parenchymal activity is seen at 3-5 min  Activity in collecting system and bladder by 4-8 mins.
  44. 44. DTPA normal
  45. 45. Renography  A Time Activity Curve  Graphic representation of uptake and excretion of radiopharmaceutical  Information is displayed from time of injection to abt 20-30 mins
  46. 46. Renogram Phases  FLOW / VASCULAR PHASE  ( 30 MIN ) (RADIONUCLETIDE ANGIOGRAM) • • FUNCTIONAL PHASE II. Parenchymal phase(uptake) Last for 30-60 sec. • Max activity 3to 5 min Max activity 4-6 secs • UPTAKE AT 2 TO 3 MIN FOR after peak aortic activity SPLIT FUNCTION III. Washout (excretory) phase no activity after 30 min
  47. 47. RENOGRAM PHASES
  48. 48. Data obtained from renogram  Time to peak cortical activity- 3-5 min  Half-time excretion- time for half of peak activity to be cleared from kidney. N – 8-12 mins  Cortical activity at 20 min/ peak activity : < 0.30 on MAG3 renogram.
  49. 49. RELATIVE/SPLIT FUNCTION  Contribution of each kidney to the total function % Lt kid = net cts in Lt ROI --------------------------------------- x 100% net cts Lt + net cts Rt ROI ROI: Region of interest Normal Borderline Abnormal 50/50 - 56/44 57/43 - 59/41 > 60/40 Taylor, SeminNM Apr 99
  50. 50. Relative (split) function ROI’s
  51. 51. Quantitation of Renal Function GFR & ERPF measurement  Two methods : Plasma sample based clearances :  The amt of activity remaining in blood at prefixed times is a measurement of activity not yet cleared – indirect measure of activity already cleared.  More accurate ,but requires determination of pharmaceuticals levels in plasma and some times in urine. 
  52. 52.    Camera based clearances : Counts are obtained from syringe before inj. & subsequently over kidneys after injection. No blood and urine collection. Sufficiently reliable method.
  53. 53. Anatomic(Cortical) Imaging (Tc99m DMSA or GH )    Images obtained after 2 to 4 hrs of injection Posterior/ right post. Oblique/ left post. Oblique NORMAL FINDINGS Smooth contour with Homogeneous activity Less uptake in medulla No activity in PCS
  54. 54. Diuretic (Furosemide) Renal Scan  Obstructive uropathy (hydronephrosis, hydroureter) may lead to obstructive nephropathy (loss of renal function) Indications:  Evaluate functional significance of hydronephrosis  Determine need for surgery    obstructive hydronephrosis - surgical Rx non-obstructive hydronephrosis - medical Rx/ follow up Monitor effect of therapy
  55. 55. PRINCIPLE  Hydronephrosis - tracer pooling in dilated renal pelvis  Furesemide induces increased urine flow  If obstructed >>> will not wash out  If dilated, non-obstructed >>> will wash out  Can quantitate rate of washout (T1/2)
  56. 56. PROTOCOL      Oral hydration prior to study NS @ 15ml/kg over 30 min 15 min prior to injection & continued in study @ 200ml/kg/24 hr Bladder catheterization is required in children Tc 99m MAG3 – agent of choice in children with limited function high target-to-background ratio, good image quality, and more accurate numerical values
  57. 57. PROTOCOL      Pre requisite – residual function to respond Diuretic given ( infants- 1mg/kg, children 0.5 mg/kg, 40 mg adults ) 20-30 min after radiotracer injection Imaging for 20 – 30 minutes, post micturition image Functional images, renogram time/activity curve( before & after ), wash out half time calculated symmetric uptake and good washout is by definition not obstructed
  58. 58. Diuretic Renal Scan Washout (diuretic response) T1/2 time required for 50% tracer to leave the dilated unit i.e. time required for activity to fall to 50% of peak
  59. 59. T1/2     Normal < 10 min Obstructed > 20 min Indeterminate 10 - 20 min Best to obtain own normals for each institution, depending on protocol used
  60. 60. Scintigraphic evaluation of Hydronephrosis Showing non-obstructive hydronephrosis of the left kidney, The arrow indicating a brisk response to intravenous diuretic.
  61. 61. Scintigraphic evaluation of Hydronephrosis Showing obstructive hydronephrosis of the right kidney, The arrow indicating a no response to intravenous diuretic.
  62. 62. “F minus 15” Diuretic Renogram  Furosemide (Lasix) injected 15 min before radiopharmaceutical  Rationale: kidney in maximal diuresis, under maximal stress  Some equivocals will become clearly positive, some clearly negative English, Br JUrol 1987:10-14 Upsdell, Br JUrol 1992:126-132
  63. 63. Evaluation of Renovascular Hypertension Captopril Renal Scan (ACEI Renography)
  64. 64. Captopril Renal Scan (ACEI Renography) Renovascular Disease  Renal artery stenosis (RAS)  Ischemic nephropathy  Renovascular hypertension (RVH) RAS ≠ RVH
  65. 65. Renin-Angiotensin System RAS Angiotensinogen Renin Angiotensin I Captopril ACE Angiotensin II Aldosterone Vasoconstriction HTN
  66. 66. Effect of RAS on GFR
  67. 67. Renovascular Hypertension  Prevalence   <1% unselected population with HTN Clinical features  Abrupt onset HTN in child, adult < 30 or > 60y  Severe HTN resistant to medical Rx  Unexplained or post-ACEI impairment in ren fct  HTN + abdominal bruits If these present - moderate risk of RVH (20-30%)
  68. 68. Diagnosis of RAS  Gold standard: angiography  Initial non-invasive tests:    ACEI renography Duplex sonography Other tests:  MRA - insensitive for distal / segmental RAS  Renal vein renin levels
  69. 69. Captopril Renal ScanMAG 3  Tc 99m MAG 3 = gold standard  Stop ACE inhibitors 48 hrs prior and no solid food before 4 hrs  Before procedure, orally fluid – 10 ml/kg  Hydration continued i.v. 4ml/ min  Baseline BP & PR recorded→ captopril 50 mg
  70. 70.  Protocol: 1 day vs. 2 day test  1 day test: baseline scan (1-2 mCi) followed by post-Capto scan (8-10 mCi)  2 day test: post-Capto scan, only if abnormal >> baseline
  71. 71. Abnormal captopril Renography      Delayed time to maximal activity >11 minutes(normal -5min) Significant asymmetry of peak activity of each kidney Marked cortical retention of radionuclide A marked decrease in the GFR of the ipsilateral kidney. 20-minute counts /peak counts [N <0.3 ], 0.15 change is considered significant.
  72. 72. Captopril Renal ScanMAG 3 MAG3 RENOGRAM CAPTOPRIL RENOGRAM TIME/ACTIVITY CURVE
  73. 73. AFTER 48 HOURS MAG3 RENOGRAM CAPTOPRIL RENOGRAM TIME/ACTIVITY CURVE
  74. 74. AORTOGRAM
  75. 75. ACEI Renography   In normal renal function - sens/spec ~ 90% In poor renal function / ischemic nephropathy, ACEI renography often indeterminate >>> do MRA, Duplex US, angiogram
  76. 76. Renal Cortical Scintigraphy Indications  Determine involvement of upper tract (kidney) in acute UTI (acute pyelonephritis)  Detect cortical scarring (chronic pyelonephr.)  Follow-up post Rx
  77. 77. CONTD..     gold standard 99mTc DMSA The radiotracer is taken up only by functioning PCT mass Pyelonephritis impairs tubular uptake of radiotracer, these areas appear as unexposed or underexposed Persisting areas on follow up indicates irreversible renal damage or scarring.
  78. 78. Renal Cortical Scintigraphy Cold Defect  Acute or chronic PN  Cyst  Tumors  Infarct  Trauma (contusion, laceration,hematoma) Cortical defects are not always d/t infection & all DMSA defects are not necessarily scars. 
  79. 79. —2-year-old girl with fever. Lim R AJR 2009;192:1197-1208 ©2009 by American Roentgen Ray Society
  80. 80. Renal Cortical Scintigraphy Congenital Anomalies  Agenesis  Ectopy  Fusion (horseshoe, crossed fused ectopia)  Polycystic kidney  Multicystic dysplastic kidney  Pseudotumors (fetal lobulation, hypertrophic column of Bertin , lobar nephronia)
  81. 81. NORMAL DMSA SCAN
  82. 82. HORSE SHOE KIDNEY
  83. 83. Horseshoe kidney with normal function
  84. 84. RENAL AGENESIS
  85. 85. Patient with Recurrent UTI Tc99m-DMSA renal SPECT scintigraphy Ectopic left kidney with multiple scars
  86. 86. Renal Transplant Evaluation:      Anterior images are obtained. Normal perfusion study: radioactive bolus reaches the renal transplant simultaneously with iliac vessels. Max parenchymal phase :3-5 min Bladder activity appears : 4-8 min Up to 2 weeks after Tx, prominent visualisation of ureter due to edema at UV anastomotic site.
  87. 87. Renal Transplant Scintigraphy Transplant kidney is showing good perfusion, uptake and drainage of radiotracerNormal Study Tc99m-DTPA renal dynamic scintigraphy
  88. 88. POST OP 1 WEEK POST OP 2 WEEKS
  89. 89.  Acute Tubular Necrosis: Preserved or mildly reduced renal perfusion but diminished renal function and progressive cortical retention of tubular agents. Acute Rejection : Poor perfusion than function in early stage Renogram demonstrates a diminished nephrogram phase and delayed appearance of bladder activity.
  90. 90. Renal Transplant Scintigraphy Acute Tubular Necrosis Acute Rejection Tc99m-DTPA renal dynamic scintigraphy
  91. 91. Renal Transplant Scintigraphy Transplant kidney is showing poor perfusion, uptake and drainage of radiotracer- Chronic Rejection Tc99m-DTPA renal dynamic scintigraphy
  92. 92. Cyclosporin nephrotoxicity :  Scintigraphic appearance similar to ATN, with relative good transplant perfusion and poor tubular function.  Compared to ATN ,it occurs several weeks after transplatation.
  93. 93. Renal transplants scintigraphy Surgical complications Urinary leak-Initial photopenic defect accumulation of radiotracer with progressive Hematoma/ Abscess- Initial photopenic defect not changing with time. Lymphocele- Initial photopenic defect- equal to background activity in delayed images. Ureteral obstruction Arterial stenosis and hypertension
  94. 94. Renal Transplant Scintigraphy 10th Post operative day of renal transplant decreased urine output and pelvic collection Urinary leak
  95. 95. Renal Transplant Scintigraphy 2nd Post operative day of renal transplant Hematoma / abscess
  96. 96. Renal Transplant Scintigraphy 7th Post operative day of renal transplant c/o Increased serum creatinine and pelvic collection Lymphocele
  97. 97. Radionuclide Cystogram INDICATIONS  Assess effect of therapy / surgery  Screening of siblings of reflux pts  Evaluation of children with recurrent UTI (30-50% have VUR) PROs  More sensitive  100 times less radiation CONs  Inferior anatomic deleniation
  98. 98. Radionuclide Cystogram
  99. 99. Refrences     Oxford text book of clnilcal nephrology-3rd ed. Essentials of Nuclear Medicine Imaging – Mettler & Guiberteau Brenner and Rector’s The kidney– 9th ed. www.google.com

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