Dual Source CT - Cardiac Sequence

SOMATOM Definition Cardiac Scanning

Joerg Hausleiter, MD; Franziska Herrmann, MD; Stefan Martinoff, MD
German Heart Center, Munich, Germany
 |  七月 25, 2007


A 66-year old male patient was presented to rule out severe calcification and significant stenosis. The patient had a history of high cholesterol as well as a family history of cardiovascular disease. Since the patient was free of symptoms and showed a stable heart rate, a cardiac sequence mode was selected to achieve the lowest possible radiation exposure.


Calcium scoring excluded significant calcifications, with the resulting score below the age-related 10th percentile. CT Angiography did not reveal any high-grade stenosis, with multiple very minor soft plaques without any hemodynamic relevance. (Fig. 1-3)


The SOMATOM Definition, as the world’s first Dual Source CT, allows for a true temporal resolution of 83 ms and thus increases robustness for cardiac scanning. Here a coronary CT angiography was performed with cardiac sequence technique, a so-called step-and-shoot mode. For this, a prospectively triggered acquisition mode is used resulting in lowest possible radiation exposure. In this patient (BMI 26.6) the CTA was performed with an effective dose of 1.5 mSv.


Examination Protocol

SOMATOM Definition
Exposure time
100 kV
Effective mAs
197 mAs
Rotation time
0.33 s
Temporal resolution
83 ms
Slice collimation
0.6 mm
Reconstructed slice thickness
0.6 mm
Effective dose                              
 1.5 mSv
Contrast material volume                
80 ml
Flow rate
5 ml/s
Saline chaser bolus
50 ml, 5 ml/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 Healthineers 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.