Dual Source peripheral Run-off

SOMATOM Definition vascular CTA

Hatem Alkadhi, M.D.
Institute of Diagnostic Radiology, University Hospital Zurich, Switzerland
 |  2007-03-23


A 71-year-old man arrives in the University Hospital Zurich with a long history of diabetes. After short walks of 100 meter the patient complains of severe pain in the lower extremities, forcing him to pause. In the initial ultrasound diagnosis a severe occlusion of the left arteria femoralis could be detected. For further verification a CT scan is requested immediately. The patient was scheduled for a CTA of the peripheral vasculature with the SOMATOM Definition. A contrast enhanced CTA scan of the lower extremities was performed on the DSCT.


The excellent image quality allowed precise visualization of the entire vasculature tree. The Dual Source run-off study permits a fast localization of the origin of the pain with respect to severe calcifications of left arteria femoralis. The corresponding collateral vessels could be visualized, explaining the relive of patient’s pain after pausing motion. Based on this single study, the patient was considered a candidate for endovascular repair.


The SOMATOM Definition utilizes Siemens‘ proprietary z-Sharp™ Technology enabling CT images with highest diagnostic detail, clarity, and speed. z-Sharp Technology significantly increases resolution without a corresponding increase in dose provides, permitting the industry’s highest isotropic resolution of 0.33 mm at any scan and rotation speed, and at any position within the scan field.

Examination Protocol


Scanner SOMATOM Definition
Scan area Peripheral Angiography
Scan length 1050 mm
Scan time 23 sec
Scan direction Caudo-cranial
kV 120 kV
Effective mAs 157 eff. mAs
Rotation time 0.5 sec
Slice collimation 0.6 mm
Spatial resolution 0.33 mm
Reconstructed slice thickness 1 mm
Increment 0.8 mm
CTDIvol 74.36 mGy
Kernel B30f
Contrast material volume 100 ml
Flow rate 3 ml/s
Bolus tracking On, ROI in infrarenal aorta, threshold 100 HU


The information presented is for illustration only and is not intended to be relied upon by the reader for instruction as to the practice of medicine. Any health care practitioner reading this information is reminded that they must use their own learning, training and expertise in dealing with their individual patients. This material does not substitute for that duty and is not intended by Siemens Healthcare to be used for any purpose in that regard.

The drugs and doses mentioned herein are consistent with the approval labelling for uses and/or indications of the drug. The treating physician bears the sole responsibility for the diagnosis and treatment of patients, including drugs and doses prescribed in connection with such use. The Operating Instructions must always be strictly followed when operating the system. The source for the technical data is the corresponding data sheets. Results may vary.