FAQ
For optimal diagnosis of coronary
artery disease, it is recommended
that patients should be:
Off Propranolol for at least 24 to 48
hours prior to exercise studies to allow
the greatest likelihood of achieving
an adequate stress.
Long acting nitrates should be
discontinued for at least four hours
and Nitroglycerine at least one hour
before initiation of the study.
Adjustment of patient medications,
however, must be ordered by the
referring physician.
For most protocols, separate female
normal limits are required in order to
account for the breast attenuation
which alters the normal distribution
of the anterior wall. Even with these
normal limits, the breast may still be
a source of artifact, particularly
in large-breasted women.
For optimal diagnosis of coronary artery disease, it is recommended that patients
should be:
Off Propranolol for at least 24 to 48 hours prior to exercise studies to allow the
greatest likelihood of achieving an adequate stress.
Long acting nitrates should be discontinued for at least four hours and
Nitroglycerine at least one hour before initiation of the study. Adjustment of patient
medications, however, must be ordered by the referring physician.
For most protocols, separate female normal limits are required in order to account
for the breast attenuation which alters the normal distribution of the anterior wall.
Even with these normal limits, the breast may still be a source of artifact, particularly
in large-breasted women.
What are the main reasons for a
false positive study?
What are the main reasons for a false positive study?
As with any quantification software,
the technical quality of the study is
directly related to the quality of the
Toolbox results. The principal source
of false positive studies is the failure
to acquire and process studies
accurately. It is important to ensure
complete quality control, as
described in the manuals that
accompany your nuclear medicine
camera system. Artifacts of
acquisition or reconstruction,
including errors in quality control, will
affect both the visual images
and the quantitative analysis. In the
event of conflicting, equivocal or
confusing results and/or findings,
always verify that proper computer
processing has been performed.
As with any quantification software, the technical quality of the study is directly
related to the quality of the Toolbox results. The principal source of false positive
studies is the failure to acquire and process studies accurately. It is important to
ensure complete quality control, as described in the manuals that accompany your
nuclear medicine camera system. Artifacts of acquisition or reconstruction,
including errors in quality control, will affect both the visual images and the
quantitative analysis. In the event of conflicting, equivocal or confusing results and/or
findings, always verify that proper computer processing has been performed.
There are a number of normal databases currently available for ECToolbox. The SPECT normal files, grouped by radiotracer, are listed below. The thallium database is applicable to both Stress/Redistribution and Stress/Reinjection protocols.
Enhanced Thallium
1 Day rest/stress Sestamibi (2)
1 Day Sestamibi AC (with Attenuation Correction) (2)
1 Day Sestamibi, adenosine stress
1 Day Sestamibi, adenosine stress, AC
2 Day Sestamibi
Tetrofosmin (stress/rest)
Myoview pharmacological stress
1 Day rest / stress Exercise Std SPECT Tc-99m (sestamibi or tetrofosmin) (1)
1 Day rest / stress Exercise Std SPECT Tc-99m (sestamibi or tetrofosmin) AC (with Attenuation Correction) (1)
Dual-Isotope (Thallium rest, Sestamibi stress)
Optimized Dual-Isotope (Thallium rest, Sestamibi stress)
Your system may include databases for use with AdreView in assessing myocardial innervation. Three options exist, for different types of reconstruction. The DSP option assumes an OSEM reconstruction methodology.
AdreView Deconvolution of Septal Penetration (DSP)
AdreView Filtered Back Projection (FBP)
AdreView Ordered Subset Expectation Maximization (OSEM)
There are three databases for the G.E. Healthcare CZT detector cardiac camera, applicable to either sestamibi or tetrofosmin:
1 Day rest / stress Exercise Tc99m DNM 530c (1)
1 Day rest / stress Exercise Tc99m DNM 530c AC (AC from CT) (1)
1 Day rest / stress Exercise Tc99m DNM 530c Prone (1)
There is a group of separately-licensed normal databases for PET. PET perfusion options include:
Rubidium (with line source-based Attenuation Correction)
Rubidium CT AC (with CT-based Attenuation Correction) (2)
Rubidium CT AC 2013 (1)
Ammonia (N-13)
Also part of the PET group are databases for comparing myocardial perfusion and metabolism. These files access the rest portion of the indicated perfusion database, together with metabolism information derived from F-18 FDG PET studies. Selecting one of these options will activate the Match/Mismatch tool instead of the Polar Maps tool in the ECToolbox application.
Rest Rubidium / FDG
Rest Rubidium CTAC / FDG 2
Rest Ammonia / FDG
Rest Enhanced Thallium / FDG
Low Dose Rest Tetrofosmin / FDG
Low Dose Rest Sestamibi / FDG
Low Dose Rest Sestamibi with AC / FDG
High Dose Rest Tetrofosmin / FDG
High Dose Rest Sestamibi / FDG
Note: There is no separate FDG normal database apart from the combination files listed above. When selecting resting perfusion and F-18 FDG data that are part of a Dual Isotope Simultaneous Acquisition study, be sure to use the Verify screen to select the most appropriate normal file, and make sure the isotope for the FDG study is "F-18".
The list of normal databases also includes the item "None", which allows you to review a study with no normal file comparison, and therefore no blackout or standard deviation polar maps.
(1) This normal database has been optimized for use with IDS.
(2) For legacy data, the use of this normal database will automatically be upgraded to its optimized counterpart.
Are there any tips to manually
setting Apex and Base limits?
Are there any tips to manually setting Apex and Base limits?
You may have to make the circle smaller to exclude bowel and liver activity. It may not be possible to completely exclude this activity in some cases.
You may have to enlarge the circle if the LV is much wider at the base than in the mid ventricular region. Examining the center and radius in relation to several short axis slices may be helpful to ensure the best parameter selection.
The appropriate short axis base slice should have a backwards "C" shape, and should include the inferior wall of the ventricle. Because of perfusion defects, not all studies will fit this pattern.
The appropriate short axis apex slice should have a "button" appearance (not a ring). Because of perfusion defects, not all studies will fit this pattern.
If an apical perfusion defect is present, you may have to increase image intensity to determine how far "out" to move the apical line cursor. In this case, you should set the apical line where you think the apex would have been if there was no defect.
The appropriate base slice will often be different for different gates. For example, the base slice for gates around end systole may be closer to the center of the ventricle, and will be further "out" at the beginning and end of the cycle. The apex may also change during the cycle, but usually not as much as the base.
In a case where there is poor function, heart motion is reduced, so the apex and base slice numbers will change less from gate to gate.
It is recommended that the apex and base slice numbers not change by more than 1 from one gate number to the immediately following gate number.
Are there shortcut keystrokes
available to speed up manual
processing of the Gated Params?
Are there shortcut keystrokes available to speed up manual
processing of the Gated Params?
Holding the CTRL key and dragging will first set all the centers to match the image under the cursor, and then move the center on each gate.
Holding the ALT key and dragging will move all centers relative to their previous position.
Holding the CTRL key and dragging any apex selector line will first set all apex selector lines to match the image under the cursor, and then move the line on each gate. The base can be set similarly.
Holding the ALT key and dragging the apex selector line will move all apex selector lines relative to their previous position. The base can be set similarly.
To shift any row left or right, click the left or right mouse button, respectively, over that row.
What Filters are available for the
gated slice images?
What Filters are available for the gated slice images?
You can filter spatial, temporal, both spatial and temporal or none. This filter is for display only, and does not affect functional calculations. Filters can be changed at any time.
What's the difference between
PreFilter and Filtering of the
gated data?
What's the difference between PreFilter and Filtering of the
gated data?
PreFiltering effects both the images displayed and the functional calculations. Filtering only effects the displayed images.
What do the images on the Polar
Maps page represent?
What do the images on the Polar Maps page represent?
The top row shows raw, unprocessed plots depicting perfusion to the entire left ventricle. The Reversibility map is produced by subtracting stress from rest after a count normalization step, and thus highlights areas that are more normal at rest.
Maps on the second and third rows relate the current study to the selected normal file. In the second row significant perfusion defects are shown in black. On the rightmost map of this row, defect pixels which reverse at rest (are significantly more normal) are set to white. For defects and reversible areas, a threshold is used with the normal file.
In the third row, non-white pixels represent any difference from the normal file, without using a threshold. Colors used in this row correspond to different numbers of standard deviations below normal, which are labeled on the color bar with red numerals.
There is an optional fourth row showing polar maps that reflect the ratio between stress and rest counts. To display these maps, use the "Show Ratio" checkbox on the left of this page. The ratio maps will be meaningful only if the stress and rest doses have been entered by the user.
The 17 segment perfusion scores can also be assigned on this screen. Use the Scores checkbox on the left side of the display to show the scores. To change a score, click the number and make a selection from the dropdown. Scores range from zero (normal) to 4 (absent perfusion).
What is the difference between the
two weighting options on the
Polar Maps page?
What is the difference between the two weighting options on the
Polar Maps page?
The Distance-weighted polar map is constructed so that each ring in the polar map is the same width. This map offers an accurate assessment of the defect location, but may distort defect size.
The volume-weighted polar map is constructed so that the volume of the apex and the remainder of the myocardium that is represented on the polar map is proportional to the volume of the corresponding slice. This makes the relative two-dimensional area of a defect equal to the relative three dimensional volume of that defect. This map offers an accurate assessment of the defect size, but may distort defect location.
Why do some of the Sum Stress
Scores have circles or squares
around them?
Why do some of the Sum Stress Scores have circles or squares
around them?
Scores that have been modified by IDS are displayed with circles around the numbers. Un-modified scores have no circles. By using the mouse to hover over a score, you will briefly see a display which gives the original score, as well as the IDS score. A physician interpreter can manually modify any of the scores by left-clicking the segment and selecting a score from the dropdown list that appears. If this score is different from the default score, it will appear in a square box. To dismiss the droplist without making a selection, move the pointer out of the list and right-click.
What is the best technique to
inject dose for a CFR study?
What is the best technique to inject dose for a CFR study?
There should be a saline push after the dose and it should be more immediate then what is demonstrated in the bad bolus figure. The graphs of the bad bolus look like the push is 10 or so sec after the end of the ammonia dose. We recommend using a 3-way stopcock. One hand on the dose and one hand on the push. As soon as the dose is in, flip the stopcock and push the saline without delay. Do not try to flush with the same syringe as the dose, or to flush remaining activity from the dose syringe. Make sure the push saline volume is enough to completely clear the line and catheter. Also, the bad bolus image demonstrates that the scanner was started a little too late. The scanner should start sooner ( or inject a little later) so there is some baseline before the peak starts to rise.
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