Reliable in-stent lumen visualization with Dual-Source CT coronary angiography

Annick C Weustink, MD and Nico R Mollet, MD, PhD
Departments of Radiology and Cardiology, Erasmus Medical Center, Rotterdam, the Netherlands
 |  2007-01-29

History

A 58-year-old man with a history of hypertension and hypercholesterolemia was admitted to the hospital with symptoms suspected of stable angina pectoris. The patient was referred to conventional coronary angiography after a positive exercise-ECG test. Conventional angiography showed significant stenoses at the level of the proximal right coronary artery (RCA) and the proximal left anterior descending coronary artery (LAD). Percutaneous intervention was undertaken and one bare-metal stent in the RCA and two overlapping bare-metal stents in the LAD were successfully implanted. The patient was referred to follow-up CT coronary angiography after 18 months.


Diagnosis

The patient was scanned on a Dual-Source CT (DSCT) scanner. Nitroglycerine was administered prior to the CT scan; however, the patient did not receive pre-scan beta-blockers. The patient had a heart rate of 76 beats/minute during the CT scan. DSCT coronary angiography was able to reliably rule out the presence of in-stent restenosis in both the RCA and LAD stents.


Comments

The SOMATOM Definition CT scanner is using two X-ray sources and two detectors at the same time. This is one of the important features for cardiac CT scanning. It allows scanning of the heart with a heart rate independent temporal resolution of 83 ms. As a result, high-quality images of the rapidly-moving coronary arteries are obtained even in higher heart rates. Moreover, the adaptive pitch and use of prospective ECG tube modulation allows significant reduction of the radiation exposure during cardiac CT scanning, especially in higher heart rates. This example shows clear delineation of the stents with excellent visualization of the in-stent lumen without the need for pre-scan beta-blockers in a patient with a heart rate of 76 beats/minute. It demonstrates the potential of DSCT coronary angiography to rule out the presence of in-stent restenosis in follow-up patients after percutaneous intervention procedures.
 

Examination Protocol

Scanner SOMATOM Definition
Scan area Heart
Scan length 103 mm
Scan time 7,3 sec
Scan direction Caudo-cranial
Heart rate 76
kV 120 kV
mAs 400 mAs/rot
Rotation time 0.33 sec
Temporal resolution HR independent 83 msec
Slice collimation 0.6 mm
Spatial resolution 0.33 mm
Pitch 0.32
Reconstructed slice thickness 0.75 mm
Increment 0.4 mm
Prospective ECG-tube modulation On, window: 30-60%
CTDIvol 45,31
Kernel B46f
Contrast material volume 90 ml
Flow rate 5,5 ml/s
Bolus tracking On