Nuclear Cardiology Dynamic and PET

What are the two methods of dynamic cardiac imaging we can preform in nuclear medicine?

First Pass Study

Gated blood pool imaging (MUGA,RVG, ERNA or RNA)

What are indications for a First pass study

eval patients with

LV dysfunction

Interventricular shunts

Myocardial ischemia

MI

What are the advantages of first pass studies

tracer activity is limited to 1 chamber at a time

background is decreased

rapidly completed

What are the disadvantages of first pass studies

gamma cameras must be able to acquire data at 200,000 counts per second or greater

speical multi crystal cameras with high count rate capabilities are optimal but not widely available

increased count rate= increased sensitivity

What is the minimum dosage for a first pass study

10 mCi

What types of imaging would be preformed for a first pass study

gated images

What types of Tc tracers would be use for a first pass study

Sestamibi, tetrofosmine, pentetate and pertechnetate

What tracers should we NOT use for a fast pass study

MAA, SC (sulfur colloid), Tl-201

When preforming a fast pass exam, the volume should be greater than for a good bolus

1mL

How fast should a bolus be pushed when performing a LVEF fast pass study? What should follow it?

over 2-3 seconds

10ml flush

How fast should a bolus be pushed when performing a RVEF first pass study? what should follow it?

3-4 seconds

10 mL flush

When performing a first pass study what baseline test should be preformed before the injection of the tracer? why?

baseline ECG to assess rhythm

Through which veins are we injecting for first pass study

The right AC (median basilic vein) or jugular for direct path to superior vena cave

How can we tell it is a good bolus during a first pass study

time activity curve over superior vena cave, calculate FWHM

What is the rate of data acquisition for a first pass study

16-30 frames/sec or 1,200 frames in 60 sec

What matrix size would we use for a first pass study

64×64

What type of collimator would we use when preforming a first pass study.

high sensitivity

when imaging the patient under the camera a first pass study should be positioned at the top of the FOV, and the should be within the FOV

Sternal notch (at top of FOV)

xifoid (within the FOV)

How would the camera be oriented when assessing the LVEF during a first pass study

Supine or upright

LAO view

How would the camera be oriented with assessing the RVEF during a first pass study

supine or upright

RAO view

How would the camera be oriented when assessing both ventricles during a first pass study

anterior

During first pass study describe the sequential visualization a good bolus would give

Superior vena cava

RA

RV

Pulmonary artery to lungs

Pulmonary veins

LA

LV

Aorta

When interpretating a first pass study what are we looking for

EF

Left to right shunt

Right to left shunt

When interpreting a first pass study if a patient has a left to right shunt some of the oxygenated blood returning from the lungs will

will go through the shunt and circulate back to the lungs instead of the body

When interpretating a first pass study if a patient has a right to left shunt, some of the deoxygenated blood returning from the body will instead of

go through the shunt and be sent out to the body

On a time activity curve do the low points represent diastole or systole

systole

on a time activity curve do the high points represent diastole or systole

diastole

How would a right to left shunt be interpretate on a first pass study

appearance of bolus in left side of the heart and aorta before the appearance of lung activity

When interpreting a time activity curve for a left to right shunt A represents and B represents

Normal flow (1 peak)

left to right shunt (2 peaks)

In gated blood pool imaging how is data collected

over many cardiac cycles using ECG gating

Gated equilibrium is another name for

Gated blood pool imaging

gated cardiac blood pool study is another name for a procedure

Gated blood pool imaging

equilibrium radionuclide angiography (ERNA) is another name for a procedure

Gated blood pool imaging

Radionuclide ventriculography (RVG) is another name for a procedure

Gated blood pool imaging

Multiple gated acquisition study (MUGA) is another name for a procedure

gated blood pool imaging

What are the indications for gated blood pool imaging

Assessment of cardiac function in chemotherapy patients

Quantification of ejection fraction (LVEF, RVEF)

Estimation of wall motion abnormalities

detection of ventricular aneurysm

detection of ventricular regurgitation

eval of cardiotoxicity

Follow up of medical/surgical therapy

Why would we preform a gate blood pool image instead of a full stress test

its own exam because pt dont need stress test just EF

What is the patient prep for a gated blood pool imaging

none

What is the most commonly used radiopharmaceutical for a gated blood pool imaging

Tc-99m labeled RBCs

What are the 3 ways we can label RBCs

in vitro

modified

in vivo

When using the in vivo labeling method, blood is labeled

inside the body

When using the in vitro labeling method blood is labeled

outside of the body using an ultratag kit

The advantages of using an in vivo/vitro method of blood labeling

High efficiency (95%)

absence of blood manipulation

The in vivo method of blood labeling has a % labeling efficiency

60-90%

Describe the steps take when labeling blood using in vivo method

inject stannous ion

wait 20-30 min

inject 99m Tc-Pertechnetate

free 99m Tc is secreted through gastric musca and kidneys

not able to see bleed in stomach, small bowel and or the colon

what are the disadvantages of using the in vivo method

labeling constancies variable (60-90%)

Free 99m Tc is secreted through gastric mucosa and kidneys

not able to see bleed in stomach, small bowel and/or the colon

What is the advantage of using the in vivo method

convenient and easy

What blood labeling methods use stannous pyrophosphate

In vivo

modifies in vivo/in vitro

what is cold stannous pyrophosphate used for in blood labeling

to pretreat RBCs for labeling

What is the optimal dose of stannous pyrophosphate when labeling RBCs

0.5-1-0 mg

What if too little of stannous pyrophosphate is used when labeling RBCs

dose of Tc will not properly label RBCs

What will happen if too much of stannous pyrophosphate is used when labeling RBCs

some of tin will circulate freely and tag to Tc outside of RBCs

What will happen to image quality if too much or too little of the stannous pyrophosphate is administered when labeling RBCs

results in increased background as a result of free Tc

Describe the steps taken when labeling blood using the in vivo/vitro method

IV injection of stannous ion

blood sample is collected into a syringe containing Tc-pertechnetate and anticoagulant

re-injected

Describe the steps taken when labeling blood using the in vitro method

1-3ml of blood withdrawn into syringe containing anticoagulant

let sit for 5 min

add sodium hypochlorite and acid citrate dextrose (ACD)

add Tc-Pertechnetate

wait 20 mins (no longer then 60 min) and inject

T/F: when using the In vitro method to label blood, once the tracer has been added, we can use a sample that has been sitting for more than 60min

False

T/F: When using the In vitro method to label blood, we can inject immediately after adding the Tc-99m Pertechnetate

false

T/F: When using the In vitro method to label blood, we have to wait at least 60 minutes after the Tc-99m Pertechnetate has been added before injecting.

false

T/F: When using the In vitro method to label blood, once the Tc-99m Pertechnetate has been added, we have to wait at least 20 minutes, but no more than 60 min before injecting

true

What is the advantage of using in vitro method for labeling blood

High labeling efficiency, superior imaging quality

Describe the procedure for a gated equilibrium study

In Vivo, In Vitro, or modified In Vivo/In Vitro labeling of RBC’s w/ Tc-99m

3 gated planar images obtained

• Anterior

• LAO

• Lft Lateraral

What views are obtained when performing a gated equilibrium study?

planars:

• Anterior

• LAO

• Lft Lateraral

T/F: When performing a MUGA (multiple gated acquisition study), an ECG rhythm strip should be obtained and reviewed before injection

true

Why should a ECG rhythm strip be obtained and reviewed before injection during a MUGA procedure?

rapid atrial fibrillation or frequent PVCs (premature ventricular contractions) are contraindications to study

One cardiac cycle can be divided into intervals of ___

8 (16, 24. or 32) frames

What triggers gating in cardiac images?

R wave

During a gated study, 24 frames per cardiac cycle are obtained.  If a patient’s heart rate is 65 bpm, the length of time per  frame is:

a. 38 msec

b. 3.8 msec

c. 41 msec

d.4.1 msec

3.8 msec

In a gated study, if the patient’s heart rate is 65 bpm, and 24 frames per cardiac cycle was obtained, How do you calculate the length of time per frame in msec?

60 sec/min divided by 65 beats/min = 0.92 sec/beat

divide by 24 frames = 0.038 sec X 1,000 = 38 msec

Which view provides the best separation between the L. and R. ventricles during a gated study?

LAO

How should a technologist reposition the camera if trying to separate the atria from the ventricles in a gated study?

apply a 5-10 degree caudal tilt

From the best LAO view, the anterior and lateral views are obtained ± ____ degrees

45 degrees

how would the camera be positioned during a gated study if trying to visualize the Right ventricle?

20 degrees anterior (5 degrees of caudal tilt)

Based on this image, which is systole and which is diastole?

1st row diastole, 2^nd row systole

During a gated study, in what views would we potentially apply a caudal tilt?

only for LAO or RAO

When performing a gated study, can we use a caudal tilt for anterior or lateral views

no

If we apply a caudal tilt to the camera, we are tilting the camera towards the _______

Pelvis (caudus)

How does a caudal tilt affect images?

used to elongate ventricles

When performing a gated blood pool imaging, are we acquiring rest or stress images?

rest

During a gated equilibrium study, what energy window are we using?

20% window centered at 140keV

What type of collimator are we using during a gated equilibrium study?

LEHR

What is the R-R acceptance window in a gated equilibrium study?

10-15%

What matrix size are we using for a gated equilibrium study?

64×64×16

When taking images for a gated equilibrium study, we have to acquire a minimum of ________ counts per frame, or about ___ to ___ minutes per view

250,000 counts

~5-10 min

T/F: If the heart rate is irregular, imaging during a gated equilibrium study will take longer

True

How is a gated equilibrium study data reconstruted?

added together to form a representative cardiac cycle

simulates the heart beating

Qualitative anaysis of a gated equilibrium study can be used to assess:

cardiac chamber size

overall biventricuar function

regional wall motion

extra cardiac abnormalities such as aneurysms

What does Akinesis mean?

absence of wall motion

What does hypokinesis mean

decreased wall motion

What is dyskinesia

outward bulge during systole

What is stroke volume

volume of blood ejected by either ventricle during systole

what is the cardiac output

volume of blood that heart pumps per minute

CO=SV at heart rate

what is the ejection fraction

% of blood ejected from ventricules during each contraction

What does qualitative analysis of a gated equilibrium study use to analyze

LVEF

How are images processed for quantitative analysis during a gated equilibrium study

ROI’s drawn on LV at diastole and systole

Background ROI selected about 3-6 o’clock from LV

• ROI can be manually drawn or generated by computer

In images taken at end diastole, the ventricle is and counts obtained would be

relaxing

highest

in images taken at end systole the ventricle is and the counts obtained would be

contracted

lowest

How do you calculate ejection fraction

[(net diastolic counts - net systolic counts) / net diastolic counts] X 100

Calculate the Ejection fraction if ED (end diastolic counts) are 90,400 and ES (end systolic counts) are 40,000

(90,000 - 40,000) / 90,400 = 0.557

0.557 X 100 = 55.7%

What is a normal LVEF range

55-75%

What is a normal RVEF range

>40%