Dual Energy Head and Neck CTA

SOMATOM Definition Dual Energy Scanning

Anders Persson, MD, PhD
Center for Medical Image Science and Visualization (CMIV) Hälsouniversitetet/Radiologi - Linköpings Universitet

 |  2007-05-25


A 72 year old female patient arrives to CMIV at the University Hospital in Linköping, Sweden. She has been having two episodes of amarosis fugax two times last month and a severe holocephal headache for the last six hours. A CTA of the head and neck were performed at CMIV.


An occlusion of the right internal carotid artery (ICA) and a 95% stenosis of proximal part of the external carotid artery (ECA) 95% is noted. With the DE technique it was possible to visualize the region of the carotid bifurcation with the different plaque components. The ECA stenosis was first overlooked on the conventional single energy CTA images. The direct subtraction of bone without user interaction gives virtual real time display of the whole cerebral vasculature and allows immediate rule out of aneurysms and embolism. Figure 4, same image with and without i.v contrast. The patient was referred for stent angioplasty.


In the dual energy mode two x-ray sources can be operated simultaneously at different kV levels. One of the results is that the plaque composition can be better determined and calcified plaques can be separated from intra luminal contrast.

Examination Protocol

Scanner SOMATOM Definition
Scan time 6 sec
kV 140 kV and 80 kV
Effective mAs 130 mAs and 230 mAs
Rotation time 0.5 sec
Slice collimation 0.6 mm
Pitch Reconstructed slice thickness 0.75 mm
Pitch 0.8
Contrast material Ultravist®
Contrast material volume 50 ml
Flow rate 3 ml/s
Saline chaser bolus 70 ml, 3 ml/s
Iodine delivery rate 1.1 g/s



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.