Patient Preparation

The first approach is to place the ROI for Bolus Tracking in the right atrium and trigger at 120 HU. Using 80 ml of contrast then 50 ml of a 50% contrast/saline mixture, then followed by 50 ml saline.
Another perspective is to place the ROI for Bolus Tracking at the ascending aorta with the trigger at 125 HU. Using 125 ml of contrast followed by a 50 ml saline flush.

An ECG file is only shown, when a ECG protocol is selected. Therefore, please register the patient and select the protocol first. Then connect the patient to the ECG, the curve will be shown immediately on the gantry display as well as on the trigger card on the monitor.

In case the ECG signal is not perfectly displayed, after applying the electrodes on the patients chest, you might want to put a little bit of ultrasound gel on it. This helps to get a more stable and better signal.

It is a commercially available product, which needs to be diluted in water. Compared to positive oral contrast agents, which might be laxative to patients due to it's hypo osmolarity, there are no side affects as this new material is iso osmolar. The patient preparation time is a bit longer, as this material takes longer to move through the body. The image quality of body CTA examinations profit of this negative contrast material, as vessels are not hidden behind oral contrast any more. (Study: Fortschr Röntgenstr 2005; 796-799)

When preparing a patient for a virtual colonoscopy, it is advisable to do a so called faecal tagging. This simplifies the differentiation between stool rests and real lesions. The patient should drink with each meal 2 days prior to the examination approx. 7ml of oral contrast, either containing barium or iodine. One day before the examination, the patient can have a small breakfast. After this breakfast, only fluids are allowed.
Further information can be found in the following papers:
Taylor et al: Eur Radiol (2007) 17: 575–579
Barish et al: AJR 2005;184:786–792

Filling the patient with CO2 is more comfortable, as it is resorbed faster than normal room air.
When doing a comparison scan in a prone patient position, you can go down to 10 effective mAs to reduce the total radiation dose.

Data acquisition

The Effective Dose is defined as the weighted average of Organ Dose values for the irradiated organs and is expressed in mSv. It describes the stochastic radiation risk.
The Effective Dose (mSv) can be estimated by multiplying the DLP with a conversion factor determined from measurements or computer simulations. The conversion factors (f), shown in the following table, are reported by the European Commission:

Region of the body Conversion factor, f (mSv/mGy cm)
(only valid for adults)

Head 0.0023
Neck 0.0054
Chest 0.017
Abdomen 0.015
Pelvis 0.019

DLP (mGy * cm): Dose Length Product is the product of the CTDIvol and the length of the scan range (cm). Because DLP takes into consideration the geometrical extent of the irradiation, it is considered to be a better indicate of the patient dose than CTDIvol.
CTDIvol (mGy): The CTDIvol is a measurement of the dose absorbed during a CT examination. The CTDIvol gives a good estimation of the average dose applied in the scanned volume, as long as the patient size is similar to the size of the respective dose phantoms. The CTDIvol is displayed in the patient protocol and also in the Routine and Scan subtask cards.

Yes, it is possible to switch off this function. You can use the advantage of monitoring the contrast enhancement during the injection and start the scan when desired. On the following screenshot you will see where you can switch the Auto Trigger off. Also on the Trigger Subtask you get a message that the Auto Trigger function is disabled.

With this formula you can calculate the mAs/rotation for the SOMATOM Definition. Take the eff. mAs value from the SOMATOM Sensation 64 standard cardiac protocol (0.33 s rotation time and fixed pitch of 0.2).

To obtain the same image quality use:
SOMATOM Sensation 64
eff. mAs*2*0.2 = mAs/rot
on the SOMATOM Definition.

(SOMATOM Sensation 64)
800 eff.mAs*2*0.2 = 320 mAs/rot
(SOMATOM Definition)

When creating new API (Automatic Patient Instructions), make sure that you speak slowly and clearly and that you wait for 1 or 2 seconds at the end of the instruction. Remember, the patient has to listen to the instructions and then follow them. If you add a short delay to the end of the instructions before starting the scan, it will give the patient enough time to complete the instructions and you will obtain images that are motion free. For more information on how to create API's please see your operator manual or online help (F1-key).

You can use the CARE Bolus option as a Test Bolus.
How to do it:
1. Insert a Bolus tracking via the right mouse button submenu prior to the spiral.
2. Insert contrast from the right mouse button context menu. Hint: By inserting contrast you are interrupting the Auto range function, and therefore an automatic start of the spiral is not possible!
3. Start with the Topogram.
4. Position the premonitoring scan and the spiral.
5. Perform the premonitoring scan. Position and accept the ROI.
6. Start the monitoring scans and a small amount of contrast (20 ml/2.5 ml/sec.). Hint: With starting the spiral, the system switches to the Trigger tabcard. The trigger line is not shown at this stage.
7. Now you can read the proper delay from the Trigger tabcard.
8. Insert the delay in the Routine tabcard and load the spiral.
9. Start spiral and injector with the full amount of contrast.

Using a flow rate of 5ml/ sec for brain perfusion studies is sufficient. Of course, the higher the flow rate, the better the contrast enhancement in the image. A flow rate up to 9ml/ sec is practicable.

Yes, you can do this, but you still need a good reference vessel i.e. the superior sagittal sinus in its upper portion.

Yes, you can do a perfusion study after a CTA. Wait at least three minutes before doing the perfusion study after an injection. Keep in mind that the total dose of contrast should stay within department guidelines.

On the gantry display the average of 10 RR intervals is displayed. In the user interface on the trigger card the most current value is displayed.

After using Test Bolus you figured out the right transit time. Then after performing the scan there is too little contrast medium in the coronary arteries.
It can happen that the pressure limit level of the injector is too low defined, e.g. 100 PSI. This level is normally reached very quickly during angio scans. Then automatically the injector changes the flow rate, for security reasons. That means, the injection will take longer.
With as result, less contrast in the coronary arteries.
If this occurs, consult your injector manual or a physician to determine if the pressure can be changed to a higher level.

Image reconstruction

When you have loaded thin slices in the viewing card to do your reading or to do other manipulations on the images, you can easily send them into the 3D card and continue your post-processing process by clicking on the icon in the right lower corner "3D MPR" (the red marked icon on the image). Then the same series will be loaded automatically into the 3D card.

Often you see metals, like prosthesis or implants, very bright displayed on the images. The reason is that these objects have a high attenuation.
The possibility to display these metals, like gold or titanium, is to use the Extended CT scale. With Extended CT scale the CT scale uses a wider range of Hounsfield units (from -10240 to + 30710). When selected, objects with a higher attenuation are displayed within the gray scale instead of white.
See added screenshots where you can see the difference when Extended CT Scale is used or not.

In this case you have positioned the object not in the iso-center, therefore it is located outside the FOV. To bring it back to the center of the image, please use the overview functionality in the recon subtask card.
For SOMATOM Spirit only: In case this icon is not available, you can configure it under "Options"->"Configuration"->"Examination"

The bones of the children are much smoother and therefore we have to use another algorithm to calculate the image (+ screenshots).

HU Values are of crucial importance for therapy planning systems of radiation therapists:
- With huge objects the CT value is independent of the kernel. With smaller objects the kernel influences the HU values. Feed and collimation do not have any influence.
- An extended FoV of 800mm means that only 500mm are scanned, the rest will be interpolated.
- The effect on the HU values of having carbon plate tagged additionally t o the patient table should be negligible and not measurable.
- CARE Dose4D does not have any effect on the HU values.

This can be resolved by changing from 3D to axial and back to 3D on the recon card. Saving the protocol in the head first position, will resolve future issues.

As Dr. Bernd Tomandl (2004) stated in a recently published paper image quality improves when using a FOV, which is exactly adapted to the region of interest (Tomandl B. et all: CT angiography of intracranial aneurysms: a focus on post processing Radiographics 2004 May-Jun;24(3):637-55). In images, where the interesting region is only zoomed, arteries may appear blurred. Compared to datasets which were reconstructed with a smaller FOV, the vascular anatomy is shown more clearly. Therefore, it is sometimes useful to reconstruct a narrow window when CT angiography is used for therapy planning and a very detailed information is required.

By using WorkStream4D the need for time-consuming manual reconstruction steps can be eliminated.
Direct axial, sagittal or coronal image reconstruction can be stored inside the standard protocols. These recons can be started parallel to the scanning procedure on both consoles, CT Acquisition Workplace and syngo CT Workplace, and will be performed in the background.
Oblique and double-oblique reconstructions are immediately available thus enabling a better image quality even in case of a complex anatomy.


In the newest software version (syngo CT 2008B) for the SOMATOM Definition and SOMATOM Definition AS, there is a minor change in Auto Post-processing. Auto Post-processing can send images directly to the syngo 3D card on the Acquisition Workplace. In this software version it must be configured. To do so, go to: Options > Configuration > Examination > Applications and select Acquisition Workplace and finish with the button "Apply". After the configuration you will find the correct entry in the Auto Tasking subtask card.

Yes. When you click on the MPR Ranges icon, the menu pops up. There it is possible to define your ranges and save them as a macro via "Set". Via "Macro", you have access to all the saved macros. Make your choice and the settings will be applied to the current dataset.

Yes, the graphic can be switched off via the configuration menu. Go to global settings:
Options > Configuration > Dual Energy > and uncheck the option: Display Boundary of Analyzed Area. The yellow circle will be turned off after you restart the syngo Dual Energy application. This function is only available with the syngo CT 2008G and syngo MMWP 2008B software versions. See screenshot.

With syngo MMWP2008B software version, you can save the Curved Ranges within the Quantitative Coronary Analysis.To save the Curved Ranges go to "Patient" in the main menu and then select "Save Curved Ranges”. In the Patient Browser, up to 36 images are saved with an angle interval of 10 degrees.

It can happen that the patient doesn’t breath in the same amount of air during one examination with different phases. Then it would be helpful if I could link both series, venous and arterial for instance, manually.
Scroll through both datasets and find the same position. With CTRL + left mouse click you select them both. Click on the “Manual Link” icon (marked in red on the image). From now on, both series are linked, even when they consist of images with different slice thicknesses.

Because there is a 512 x 512 maximum matrix, it can happen that the whole curved MPR can not be displayed in one view. You can easily grab the yellow bar at the beginning of the range and move it to a desired position on the curved MPR line and the following images illustrate how user-friendly this feature is.