Purpose
The aim of this study was to reduce computed tomography dose index (CTDI) and contrast medium (CM) volume for characterizing left atrium (LA) and pulmonary vein (PV).
Transit time of contrast medium from right ventricle (RV) to left ventricle (LV),
and examination time were investigated.
Methods and Materials
Patients
78 consecutive patients (39 men,
age 61±12 years ) with known paroxysmal atrial
fibrillation underwent
Equipment
64-slice multi detector computed tomography (MDCT) in the caudocranial direction between Jan 2010 and Jun 2011 was included.
The data were performed using MDCT ( Aquilion 64,
Toshiba Medical Systems,Japan).
This CT system contains one X-ray tube with a 64 channel detector,
collimation of 0.5mm.
CTDI and Hounsfield units (HU) were recorded from monitor display of Aquilion 64．
Protocol
Current protocol: Non ECG-triggering,
120kV,
175mAs/rot,
Helical Pitch (HP)...
Results
The diameter of PV on non ECG-triggering (n=40) scan resulted in large distribution (19.8±11.5mm,
19.0±9.4mm,
17.6±11.7mm,
18.2±9.4mm)．
ECG-triggering scan (n=38) with R-R40% indicated the largest number (22.2±7.5mm,
19.3±5.4mm,
18.3±7.7mm,
19.0±5.4mm),
while R-R75% pointed the smallest number (19.2±6.9mm,
18.2±4.9mm,
16.9±7.0mm,
17.9±5.2mm)．
Result of the current protocol showed 26.7mGy in CTDI，12 in image noise SD,
contrast medium ratio with 1.34,
and 4.2±0.8point in visual evaluation．
The new method ended up with 23.2mGy in CTDI,
32 in image noise SD,
contrast medium ratio with 1.49,
4.4±0.6point in visual...
Conclusion
The new method increased reliability of the examination of diameter of PV.
Increase of the contrast ratio overtook rise of image noise and led 10% decline of CTDI.
10 seconds injection delay for the peak of the contrast medium decreased total injection time and volume of contrast medium from 60mL to 40mL.
References
1. Stolzmann P,
Knight J,
Desbiolles L,
et al.
Remodelling of the aortic root in severe tricuspid aortic stenosis: implications for transcatheter aortic valve implantation.
Eur Radiol 2009; 19:1316-1323.
2. Roos JE,
Willmann JK,
Weishaupt D,
Lachat M,
Marincek B,
Hilfiker PR.
Thoracic aorta: motion artifact reduction with retrospective and prospective electrocardiography-assisted multi-detector row CT.
Radiology 2002; 222:271-277.
3. Primak AN,
McCollough CH,
Bruesewitz MR,
Zhang J,
Fletcher JG.
Relationship between noise,
dose,
and pitch in cardiac multi-detector row CT.
Radiographics 2006; 26:1785-1794.
4. Achenbach...
