Computed Tomography

Patient Preparation

What is the optimum contrast injection protocol for a Triple Rule Out scan?

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.

Why can I not see an ECG curve of the patient after connecting the ECG leads?

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.

How can I improve the connection of the ECG leads?

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.

Is there proven information about the usage of negative oral contrast agent for PET-CT examinations?

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)

How can I prepare a patient for a virtual colonoscopy?

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

How can I make a CT-colonography more comfortable for the patient?

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

How can I calculate the Effective Dose?

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.

Can I switch off the Auto Trigger function when I use Bolus Tracking?

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.

How can I transfer cardiac protocols from the SOMATOM Sensation 64 to the SOMATOM Definition and have the same image quality?

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.

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

How can I create Automatic Patient Instructions?

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).

How can I change from Test Bolus to CARE Bolus?

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.

What is the Flow Rate for Brain Perfusion?

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.

Can I scan the brain perfusion series at a different area than at the basal ganglia, e.g. when the leasion is suspected at a different location?

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

Can a Neuro perfusion study be done after a CTA of another body part?

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.

Why is the display of the ECG curve on the gantry and on the user interface different?

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.

Why is there only very low contrast in the cardiac scans?

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

Is there a fast way to load images from the Viewing card into the 3D card?

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.

How can I improve the display for metal in the human body?

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.

We scanned a wrist, but we don't see it on the real time images. What can we do?

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"

What is the difference between H(Head)- and C(Child)-kernels?

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

Which factors influence the interpretation of HU values in Radiotherapy?

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.

The coronal and sagittal images in WorkStream4D are upside down. What can I do to rotate them around?

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.

Can I improve the image quality when I use an adapted Field of View?

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.

Can I save time when I use WorkStream4D for data reconstruction?

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.

Post-processing

How can I configure Auto Post-processing for syngo 3D?

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.

Is it Possible in syngo InSpace4D to Save the Settings for MPR Ranges as it is in syngo 3D?

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.

Is it possible to remove the yellow circle, that represents the Usable FoV in syngo Dual Energy?

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.

Is it possible to save curved MPR ranges in syngo Circulation?

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.

Can I link a series manually in syngo Oncology?

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.

When I create a Curved MPR, sometimes the last part of the reconstruction is not displayed. How can I visualize this missing part of the Curved MPR?

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.

Which Circulation report template can I use for printing all 4 image segments?

If you want to configure a Circulation report in which it displays 4 images on one page you must select the "CirculationLong.lst" template in the report configuration. This should allow all images to be on the same page.

Why can I not synchronize the supine and prone datasets in syngo Colonography?

syngo Colonography compares both datasets. If the filling of the colon is not equal, the icon gets dimmed. It might be helpful to use an automatic inflation system, to keep the filling constant between the two scans.

How can I change the default window settings?

In the main menu select "Options"->"Configuration" and double-click on the icon Viewer. Go to Evaluation General on the appearing task card and select the body region from the drop-down list; for example Abdomen. Now you can change the width and centre for the first and for the second default window. To save the changes, click on Apply and close the window again. The updated window values will now be used for all following scans.

How can I determine the ante torsions angle?

To determine the ante torsion angle you can use the Average functionality, which can be found in the main menu under Evaluation. It is necessary to scan an image from the hip region as well as one image from the knees and from the ankles. It is very important to use for all scans exactly the same x and y coordinates, to make sure that the resulting angle measurements are correct. After scanning, the images can be merged using the Average option. On the resulting image the ante torsion angle can be measured.

What is the definition of Z- and T- score for Osteo measurements?

The Z-score is the absolute deviation of bone mineral density (BMD) of a patient from a population collective of people with equal age and sex divided by the standard deviation: (BMD of patient in [mg CaHA/cm3] - BMD of population collective in [mg CaHA/cm3]) / standard deviation in [mg CAHA/cm3]. The unit-less Z-score compares the BMD of a patient to those of a population collective with equal age and sex.
The T-score is the absolute deviation of bone mineral density (BMD) of a patient from a population collective of young people (usually 20 years) with equal sex divided by the standard deviation: (BMD of patient in [mg CaHA/cm3] - BMD of population collective in [mg CaHA/cm3]) / standard deviation in [mg CAHA/cm3]. The unit-less T-score compares the BMD of the patient to those of a young population collective with equal sex.

What impact does the serial number on the Osteo phantom have in the calculation of the Osteo program?

There are three numbers on the Osteo phantom. Osteo offset, Osteo scale and the Osteo phantom number (serial number). The Osteo offset and the Osteo scale are used in the calculation of the osteo images. The serial number has no effect on the results of the program, but needs to be entered in local service. This is done by the engineer, and can be check by looking at the DICOM header under local service.

Data handling and distribution

How can I film various patients on one film sheet?

Select the desired images in the patient browser and use the drag-and-drop functionality to bring the images of the first patient onto the film. Select the images from another patient and use again the drag-and-drop functionality to move the images on the virtual film sheet. You will see that the name of the folder will change from the first patient`s name to Multiple. When you are finished you can send the images to the camera as usual.

How can I change a patient's study name when it is connected to another patient's examination?

Please archive the patient with the correct information and delete the data from the local database. Use the Edit/ Correct functionality to change name and information of the remaining patient. Archive, film or network this exam as necessary.

How can I download the DICOM viewer?

To provide referring physicians and patients with a tool, that allows for viewing DICOM images on normal PC`s, you can download from the following link the syngo fast view:
more

What type of DVD's I can use?

Siemens recommends the use of DVD-R DVD's. Other types won't work properly.

Can you change patient information after scanning?

Yes, you can change the patient information by going into the Patient Browser to edit. Make sure that the data is not protected, the patient's study is not loaded into any card or listed in any queue. In the Local Database, click on the specific patient folder, study folder or series folder that needs to be edited, so that it is highlighted in the Patient Browser. Select Edit -> Correct at the top of the Patient Browser. The Correct platform will appear, and along the middle of the platform are different level tabs you can pick. Select the Series tab to change series specific information, the Patient tab to edit patient specific information etc. Once the correction is completed, put your name as modifier in the field marked “meduser” and then click OK.

How can I burn bmp or avi files onto CD?

1) bpm: Select the desired images in the patient browser and send them via Transfer-Export to offline to H:\SiteData\CDBurn.
2) avi: Record a movie in InSpace or Colonography. You can also use Camtasia to record any actions on the screen. The files will be saved on the H:\CDR_Offline device. To burn bmp`s or avi`s onto CD, you need to make sure that all wanted images are stored in the CDBurn folder. Now go to Transfer-Record offline files to start the burning procedure. In case the entry Record offline files is dimmed, you need to clear the Local Job Status and Transfer. A message in the footer will inform you as soon as the CD is finished.

Can I restore patient data that has been deleted by accident?

No, once they are deleted the DICOM information is directly deleted and therefore there is no way to get them back.

How can I delete a scan protocol?

Select Edit and then Delete Scan Protocol in the examination card.
Choose the body part by double clicking on the group folder in which the protocol is contained, then once in the folder and pick the protocol to be deleted.
Confirm this selection by clicking OK and the protocol will be deleted.

Is the sorting function Instance Date and Time at Series Level recommended?

Using the sorting function Instance Date and Time at the series level is not recommended to use with Multislice CT, as images from the same rotation are getting the same time stamp and the images might be mixed up. The selection for the series level should always be Instance Number.

How to make a CD that can be viewed on a PC?

Select the patient in the Browser and choose the series to be sent to the CD. On the Browser dropdown menu select Transfer>Export to>CD. When the platform to label a new CD in the drive opens, check the viewing tool and label the disc. This tool should be opened prior to the images. The Magic View 300 tools will then be available for manipulating the images. This is available on VB10 and higher software.

What can I do when the Local Database has disappeared from the patient browser?

Please check in the main menu of the patient browser under View-source if the entry local database is selected. If not, click onto it, so that an arrow appears in front of the entry. The local database should be visible again.

I would like to use the Camtasia Recoder. How to do this?

A few tips and tricks:
Where to find? Applications-Desktop-Camtasia-Recorder (only SOMATOM Emotion, SOMATOM Sensation and SOMATOM Definition with software version syngo CT 2006A, and higher) → Camtasia Recorder window opens up.
Basic configurations? Go to Tools-Options-Hotkeys to configure the F9 key to record/ pause and the F10 key to stop the recording. Go to Tools-Options-Program and select "Minimize before starting capture" to close the window before recording starts.
Compression mode? Go to Tools-Options-AVI-Video Setup and select "Microsoft MPEG-4 Video Codec V2" to ensure best ratio of image quality and size of the file.
What to record? Under Capture use Region if you want to focus on a certain segment of the screen. If you want to show a whole evaluation procedure, select Screen to show all working steps.
How to start? Click on F9 to start recording.
Where is it stored? It goes directly to H:\CDR_Offline\. From here you can burn it to CD.
For further information, please have a look in the Application Guide.

How can I film every n'th image?

On the Auto Tasking card in the examination card you can select every n'th image. Additionally you have the possibility to select Expose every n'th document in the Filming Layout configuration. Be careful, If you select both options, both will be applied. E.g. if you select every 2^nd image in the Auto Tasking card and every 2^nd image in the Film Layout card- you will get every 4^th image on your film sheet.

Why are the images in Filming in a backwards order?

When sending images from the browser to the film sheet, it uses the same order that is used in the browser. You can see the image order in the patient browser when selecting the series. The images are shown in the content area as little image stamps (if they are not shown here, simply go to View and select Image Stamps). Here you can see the image order, also indicating how they would appear on film. In case the last image is shown as first, just go to Sort in the browsers main menu and select Instance Number. Then the images should appear in the correct order. Now you can send the images to the Film sheet in the correct order.

We deleted accidentally the reference images from the local database. Can we get them back?

In Patient Browser go to Transfer->Import from Offline. Select from path C:\Somaris\Service\Reference Images, highlight the image file here, and click OK. Now the test images will be located in the Local Database under Reference Images patient folder.

What is a fast and easy way to search for a dedicated patient in the patient browser?

Click on patient name level and type in the first letter, for example "M" for "MickeyMouse" The system will show you the first patient name starting with a "M". If the first one is not the correct one, press "M" again and again, until you find the desired patient name.

Is it possible to store the graphic that is displayed after using CARE Bolus?

The graphic is always stored in the patient browser after finishing the examination. You can open it in Viewing or you can export the DICOM image as a bmp via Transfer-Export to offline; please select bmp as desired format.

Accessories and Hardware

How can I clean the sides of the table, the tabletop cover, gantry cover, cushions, armrests, knee supports, and head holder?

You can use the following commercially available cleaning agents:
- Commercially available washing-up liquid (without restrictions)
- Ethyl alcohol (may affect the surface)
- Surgical spirit (surfaces may fade)

For disinfection of the patient table and the accessories you can use the following disinfection agents:
- Aldehyde and Aldehyde decompositors (may discolor surfaces)
- Alcohols
- Quaternary compounds
- Organic acids
- Peroxide compounds

What is the maximum patient weight for the CT table?

For the high capacity table option on the SOMATOM Sensation Open the maximum table load is 280kg (616 lbs).
For the SOMATOM Definition, the maximum table load is 220kg (495lbs).
For all other SOMATOM CT systems the maximum table load is 200kg (450 lbs).

Is it allowed to use a defibrilator on the CT table?

No, it is not allowed. Of course, in an emergency case it is needed to do so. But please make sure, that after the defibrilation, the system is beeing restarted, so that during the start up procedure any damaged parts could be recognized.

User Assistance

How can I quickly access help topics and user guidance?

When you use the F1 button on your Acquisition-, CT- or MultiModality Workplace you get access to the Online-Help. There you will find a lot information about dedicated topics.

How can you change the time on the scanner?

Go under "Options" -> "Configuration" -> " Date/Time" and make the changes from that platform.

Computed Tomography

Computed Tomography FAQ

Patient Preparation

Data acquisition

Image reconstruction

Post-processing

Data handling and distribution

Accessories and Hardware

User Assistance

Patient Preparation

Data acquisition

Image reconstruction

Post-processing

Data handling and distribution

Accessories and Hardware

User Assistance