Significant coronary stenosis detected by coronary computed angiography in asymptomatic HIV infected subjects.

OBJECTIVES: increased incidence of acute coronary events, high rate of abnormal surrogate markers of atherosclerosis and increased amount of coronary calcium have been described in HIV infected population. To expand knowledge on coronary artery disease (CAD) in HIV patients, cardiac CT scan was performed in asymptomatic subjects with low cardiovascular (CV) risk. METHODS: A cross-sectional study using dual-source CT (MDCT) coronary angiography.was conducted in HIV-infected subjects with the following characteristics: Framingham Risk Score (FRS) ≤10, absence of metabolic syndrome, negative echocardiographic and ECG stress-test. A luminal narrowing exceeding 50% was defined as a clinically significant coronary stenosis. Calcium score was quantified using the Agatston Calcium Score method. RESULTS: Fifty-five subjects were enrolled. Significant coronary stenoses, requiring coronary angiography, were found in 16/55 (29.1%). At multivariate analysis older age was the only variable independently associated with the presence of significant luminal narrowing (p = 0.011). CONCLUSIONS: MDCT showed an unexpected, age-associated high rate of significant coronary stenosis in asymptomatic HIV positive subjects with low CV risk. These findings suggest that aggressive screening programs for coronary artery disease may be appropriate in this population; further studies are recommended to assess the appropriateness of MDCT for this purpose.

Double superior vena cava: right connected to left atrium and left to coronary sinus.

Left persistent superior vena cava connected to coronary sinus may coexist with right superior vena cava connected to left atrium. Surgical correction is not mandatory if there is no cyanosis due to a big interjugular bridging vein.

Optimizing radiation dose and image quality.

Radiation exposure is a critical issue in multidetector CT (MDCT) particularly since fast MDCT scanners have become widely available, and the method has been proposed as a noninvasive diagnostic tool for an increasing number of clinical applications. Additional features of MDCT imaging affecting individual dose are related to the inappropriate use of scanners caused by practices such as scanning beyond the area of interest or acquiring unnecessary multiphase image sets. In order to reduce individual exposure and in accordance with the ALARA principle, several strategies have been implemented over the last few years which are based on X-ray emission or optimization of scanning parameters (i.e. mAs, kV, pitch, collimation) or which take account of the individual patient's characteristics (automatic exposure control systems and ECG-pulsing techniques for ECG-gated acquisitions). These strategies allow optimization of image quality while keeping individual exposure at the lowest level. We review here these different strategies taking into account the relationship between image noise and different scanning parameters. Data from the literature are discussed, and current technological developments are considered, including initial results of dual source and SnapShot pulse technologies which have been shown to result in a significant dose reduction in ECG-gated cardiac acquisitions without compromising image quality.