Comparison of different volumes of saline flush in the assessment of perivenous artefacts in the subclavian vein during cervical CT angiography

Abstract

Objectives: The aim of this study was to examine attenuation values in the central vein and perivenous artefacts at the subclavian vein in cervical CT angiography (CTA) when using 40 ml contrast material (CM) followed by different volumes (25 ml vs 40 ml) of saline flush (SF). Methods: 61 patients underwent CTA between the aortic arch (AA) and distal to the circle of Willis (cW). After calculating test-bolus time to peak enhancement at the cW (Tc), scanning delay was represented as [(Tc + 4) -scan duration between AA and cW] s. 28 patients (Group A) received 40 ml of 370 mg iodine (I) ml -1 CM followed by 25 ml of SF, and 33 patients (Group B) received the same CM followed by 40 ml of SF, both administered through the right antecubital vein. Arterial attenuation was measured at seven points in the aorto-carotid artery and at three points in the vertebrobasilar artery. Venous attenuation in the central vein was measured at four points. Mean attenuation values were analysed quantitatively. Axial and post-processing threedimensional images were assessed qualitatively. Results: When Groups A and B were compared, there were no differences in the mean attenuation values in either the aorto-carotid artery (p50.78) or the vertebrobasilar artery (p50.82). Mean venous attenuation values were lower (p50.002) in Group B than in Group A. Although the qualitative assessment of arterial images showed no differences between the two groups overall, perivenous artefacts at the subclavian vein were assessed as less prominent (p,0.01) in Group B. Conclusions: When compared with CTA followed by 25 ml of SF, CTA followed by 40 ml of SF can reduce venous attenuation values and perivenous artefacts at the subclavian vein. Cervical CT angiography (CTA) has high sensitivity and specificity for the detection of carotid artery stenosis, suggesting that it is suitable for screening symptomatic patients with atherosclerotic disease in anterior and posterior circulation [1]. In modern 32-or 64-multidetector row CT (MDCT) systems, small volumes of contrast material (CM) can provide sufficient early arterial enhancement in the cervical CTA [1][2][3].Several reports on thoracic CT and CTA have stated that saline flush (SF) after injection of the main CM bolus into the central veins can help to reduce perivenous streak artefacts at the brachiocepalic vein and superior vena cava [4][5][6][7]. In general, the suggested flush volumes range from 15 to 50 ml, but most authors report using 15-20 ml of SF [4][5][6][7][8][9].To reduce perivenous artefacts in cervical CT on a 16-MDCT system, Yoon et al [9] used 80 ml CM followed by 40 ml of SF [9], and de Monyé at al [2] suggested the craniocaudal scan direction. We recently reported that CTA on a 32-MDCT in the caudocranial direction can provide adequate arterial enhancement using 40 ml of highly concentrated CM followed by 25 ml of SF [3]; however, perivenous artefacts were often present in the subclavian vein. To improve images of the subclavian artery and upper extremity vasculature, pushing an extra ...

Cerebral CT angiography using a small volume of concentrated contrast material with a test injection method: optimal scan delay for quantitative and qualitative performance

“…However, the test bolus method can accurately demonstrate individual circulation, and may be appropriate for CTA protocol using a small volume [8,14]. Concentrated CM at a rapid injection rate was standardised in this study, because we believe that high arterial attenuation with small venous attenuation can decrease venous overlap [9,12]. Therefore, the optimal delay for cerebral CTA using a small volume of CM with the test bolus method will be investigated quantitatively and qualitatively.…”

“…They also indicated that attempts must be made to make elaborations similar to catheter-based angiography projections, and thus an angiographic background is a good starting point for performing a good job on the workstation. We consider that minimal venous overlap on CTA can save time in establishing a diagnosis by omitting additional viewing of source images, and this can be effective for post-processing of volume-rendered images and segmentation [12].…”

“…Small branches were indicated as the superior cerebral artery, ophthalmic artery, anterior and posterior communicating artery, MCA at M2 and M3 segment, and ACA at A2 and A3 segment. Next, the two radiologists were asked to rate the quality of images showing venous overlap between the arterial and venous structures at the cW and above the cW, using axial and coronal thin-slab MIP images (6 mm slab thickness with 2 mm increments) using a four-point scale [12]: 1, indiscernible overlap exists; 2, although minimal overlap (the venous attenuation is much smaller than arterial attenuation) exists, the arterial lumen was easily recognised; 3, although moderate overlap (venous attenuation is less than arterial attenuation) exists, distinction of the arterial lumen from the venous lumen is not difficult; and 4, as severe overlap (venous attenuation is close to arterial attenuation) exists, distinguishing the arterial lumen from the venous lumen requires careful attention (Figures 2-4). The region at the cW consists of vertebral arteries, basilar artery, intracranial internal arteries, MCA at the pre-M1 bifurcation and ACA at the A1 segment.…”

Hybrid Iterative Reconstruction Algorithm Improves Image Quality and Helps to Decrease Radiation Dose in 256-Slides Craniocervical CTA

“…It was followed by 0.9% normal saline chaser bolus by using a flow rate of 4 mL/s using automated dual-syringe injector (Empower CTA dual-syringe injector) with the pressure limit set at 300 PSI. The scanning delay was predetermined by using a contrast agent bolus tracking method (Bolus Pro, Philips Healthcare, Cleveland, OH, USA) for assessment of the optimal time delay for CT scanning, to optimize contrast material enhancement in carotid arteries; the Region Of Interest (ROI) indicator was placed on a reference image obtained from the aorta [12]. A summary of the acquisition protocol is given in Table 1.…”

Optimal scan timing for artery–vein separation at whole-brain CT angiography using a 320-row MDCT volume scanner

“…However, enhancing the venous structures may interfere with detailed evaluation of the arterial structures and vice versa. 1,2,8,9 Therefore, a demonstration of artery-vein separation at brain CTA 10 is desirable for increasing diagnostic accuracy and improving surgical planning.…”