Low-dose multidetector-row CT angiography of the infra-renal aorta and lower extremity vessels: image quality and diagnostic accuracy in comparison with standard DSA

Abstract

To investigate the possibility of reducing X-ray exposure during multidetector-row spiral computed tomographic (MDCT) angiography and to compare the image quality and diagnostic accuracy of different dosages with digital subtraction angiography (DSA) in the evaluation of the infra-renal aorta and lower extremities vessels. Seventy-five patients, randomly divided into three groups of 25 patients each, were evaluated for atherosclerotic disease with four-row spiral CT angiography (4x2.5 mm) and DSA. MDCT scanning parameters were kept constant, except for milliamperage (mAs): group A: 50 mAs; group B: 100 mAs; group C: 130 mAs. Images were analysed by two vascular radiologists in consensus. DSA represented the standard of reference. The diagnostic value of MDCT and total radiation exposure were evaluated for each data set. The simulated effective dose was 3.7 mSv for 50 mAs, 8.2 mSv for 100 mAs and 13.7 mSv for 130 mAs for men, and 4 mSv for 50 mAs, 8.9 mSv for 100 mAs and 14.8 mSv for 130 mAs for women. The dose reduction was 74% for group A and 40% for group B. The evaluation of the presence and degree of stenoses revealed a sensitivity, specificity, accuracy, PPV and NPV of 96%, 94%, 95%, 83% and 99% for Group A (50 mAs), 96%, 96%, 96%, 89% and 99% for Group B (100 mAs) and 98%, 96%, 97%, 91% and 100% for the standard dose protocol, Group C (130 mAs). Low-dose scanning is thus a feasible and accurate option for four-row CT angiography of the peripheral vessels. This technique provides substantial reduction of the radiation dose delivered to the patient while maintaining optimal diagnostic accuracy.

Multidetector CT urography: experimental analysis of radiation dose reduction in an animal model

“…Minimizing radiation exposure in MDCTU is generally attempted by reducing the number of acquisitions after contrast material administration and using the lowest possible tube current or dose levels without compromising image quality [15][16][17][18][19]. Nawfel et al stated that the effective dose for MDCTU was 1.5 times higher than that for conventional IVU [20].…”

Assessment of occlusive arterial disease of abdominal aorta and lower extremities arteries: value of multidetector CT angiography using an adaptive acquisition method

“…The major advantage of MR over CT is that no ionising radiation nor iodinated contrast medium are needed. However, efforts have been made recently to reduce the radiation dose delivered during CT that include the mA dose automodulation during acquisition, as used in the present study, low dose protocol (50 mAs), as proposed by Fraioli et al [17], and low kV settings (100 kVp), as suggested by Wintersperger et al [18]. Care should be taken to use the available protocols for dose reduction in routine practice.…”

How to set up and apply reference levels in fluoroscopy at a national level

“…The definition given in the questionnaire for this type of examination may appear not specific enough. It should be noted that this type of examination may be replaced in the future by CT angiography [40,41].…”