Impaired left ventricular function has a detrimental effect on image quality in multi-detector row CT coronary angiography

Aim

To determine whether there is a relationship between left ventricular (LV) haemodynamic parameters, circulation times, and arterial contrast opacification that might affect the image quality of computed tomography (CT) coronary angiography.

Methods

Thirty-six patients were included in the study: 18 with cardiomyopathy (CM) and LV dilatation of suspected ischaemic aetiology [age 57.9±13.7 years, range 30–77 years; 14 male, four female; body mass index (BMI)=27.7±4.5, range 25.5–31.8] and 18 controls (age 62.3±9.4 years, range 47–89 years; 10 male, eight female; BMI 27.8±6.6; range 19.2–33.6). Coronary artery image quality was assessed using a three-point visual scale; contrast medium circulation times, aortic root contrast attenuation, and LV functional parameters were studied.

Results

Visually reduced contrast opacification impaired image quality more often in the CM group than the control group (27.4 versus 5.1%). A total of 55.6% CM patients had a contrast transit time ranging from 30–75s; the number of “unassessable” segments increased with increasing transit time conforming to a fitted quadratic model (R²=0.74). The relationship between LV ejection fraction and contrast attenuation may also conform to a quadratic model (R²=0.71).

Conclusion

LV haemodynamics influence coronary artery opacification using cardiac CT, and users imaging this subgroup must do so with the knowledge of this potential pitfall. The results indicate the need for further studies examining CT protocols in this clinical subgroup.