Dual Energy Head and Neck CTA

Direct subtraction of bone even in complicated anatomical regions.

Dominik Morhard, MD; Thorsten Johnson, MD; Christoph Becker, MD
Department of Clinical Radiology, Ludwig-Maximilians-University Munich – Großhadern Campus
 |  Nov 16, 2006


A 47 year old male patient arrives in the Emergency Room of the University Hospital in Munich, Großhadern. He has been suffering from a severe holocephal headache for the entire day and an acute vertigo for six hours. To rule out stroke (ischemia or hemorrhage) he is transferred directly to the CT department. An un-enhanced scan of the brain and a CTA of the head and neck are performed with the SOMATOM Definition.



The virtual real time display of the cerebral vasculature allows immediate rule out of aneurysms and embolism. A 95% occlusion of the right internal carotid artery (ICA) is noted. The patient is referred to the neuron-radiology department for stent angioplasty.


With the SOMATOM Definition, two x-ray sources can be operated simultaneously at different kV levels. The result are two spiral data sets acquired in a single scan that contain spectral information, which allows differentiation and characterization of imaged structures and tissue. For instance, one available Dual Energy application is the direct subtraction of bone even in complicated anatomical regions. Conventional bone removal approaches still require a high degree of user interaction or often suffer from artifacts due to motion between the un-enhanced and the enhanced acquisition. In comparison to conventional CT techniques, Dual Energy Head and Neck CTA can eliminate manual post processing steps and significantly reduce reading time.


Examination Protocol

Scanner SOMATOM Definition
Scan area Head-Neck
Scan length 35cm
Scan time 4,8
Scan direction Caudo-cranial
Heart rate N/a
kV 80 kV and 140 kV
mAs/ Rot 190 and 65
Rotation time 0.33 sec
Slice collimation 0.6
Slice width 1
Pitch 0.8
Reconstruction increment 0.75
CTDI 10.1
Kernel D20
Volume 115ml
Flow rate 5,3ml/s
Start delay CareBolus+3s