Intravenous contrast material administration at 16-detector row helical CT coronary angiography: Test bolus versus bolus-tracking technique
ABSTRACT To compare test bolus and bolus-tracking techniques for intravenous contrast material administration at 16-detector row computed tomographic (CT) coronary angiography.
This study had institutional review board approval, and patients gave informed consent. Thirty-eight patients (mean age, 60 years; three women) were randomized into two groups according to bolus timing technique: group 1 (20-mL test bolus with 100-mL main bolus) and group 2 (bolus tracking with 100-mL main bolus). All patients underwent electrocardiography-gated 16-detector row CT coronary angiography with 12 detectors (collimation, 0.75 mm; rotation time, 420 msec). In group 1, test bolus peak attenuation was used as a delay, while in group 2, a +100-HU threshold in ascending aorta triggered angiographic acquisition, with an additional 4-second delay for patient instruction. Attenuation was measured in the longitudinal direction throughout the examination in three main vessels: ascending aorta (region of interest [ROI] 1), descending aorta (ROI 2), and main pulmonary artery (ROI 3). Mean attenuation and slope of bolus geometry curve were calculated in each patient and ROI. Attenuation at origin of coronary arteries was measured. Student t test was used to compare results.
Mean scan delay was 6 seconds longer in group 2 (P < .05). Average attenuation values were 306.6 HU +/- 44.0 (standard deviation) and 328.2 HU +/- 58.6 (P > .05) in ROI 1, 291.6 HU +/- 45.1 and 326.4 HU +/- 62.6 (P > .05) in ROI 2, and 354.7 HU +/- 78.0 and 305.3 HU +/- 71.4 (P < .05) in ROI 3 for groups 1 and 2, respectively. Average slope values were 5.8 and -0.8 (P < .05) in ROI 1, 7.7 and 0.7 (P < .05) in ROI 2, and -1.0 and -13.3 (P < .05) in ROI 3 for groups 1 and 2, respectively. Average attenuation values in left main, left anterior descending, and left circumflex arteries were higher in group 2 (P < .05); there were no differences (P > .05) between groups in right coronary artery.
Bolus-tracking yields more homogeneous enhancement than does the test bolus technique.
- SourceAvailable from: Ahmed Sabry[Show abstract] [Hide abstract]
ABSTRACT: Objective The purpose of this study is to evaluate the role of MDCT in the depiction of coronary artery anomalies.Patients and methodsSixteen patients were included in this study. Retrospectively gated coronary CT angiography was performed in 11 patients and prospectively gated CT coronary angiography was performed in 5 patients. Post-processing techniques as maximum-intensity projection, curved multiplanar reconstruction, and volume rendering were applied to assess the origin and course of the coronary vessels.ResultsOrigin and course anomalies of the central coronary artery segments were seen in 11 patients (67%), anomalies of only coronary artery origin in 2 patients (13%), origin and course anomalies of the peripheral coronary segments in 2 patients (13%) and coronary arterio-venous fistula in one patient (7%). The origin and course anomalies of the central coronary artery segment were more common in the left coronary artery involving 8 patients (73%). Malignant inter-arterial course between aortic root and pulmonary artery or the right ventricle outflow tract was seen in 3 anomalous arteries.ConclusionMDCT coronary angiography can precisely depict the origin and course coronary artery anomalies and is recommended in young patients and before cardiac intervention or surgery to prevent possible complications.09/2012; 43(3):369–375. DOI:10.1016/j.ejrnm.2012.04.002
- [Show abstract] [Hide abstract]
ABSTRACT: To prospectively compare test bolus and bolus tracking for the determination of scan delay of pulmonary dual-energy CT angiography in patients with suspected pulmonary embolism. 60 consecutive patients referred for CTA for exclusion of PE were randomized either into a test bolus group or into a bolus tracking group. All exams were performed on a 64-channel dual source CT scanner. A standard single-acquisition dual-energy CTA was performed after injection of 100ml Iomeprol 400 followed by a saline chaser of 4 ml/s. The scan delay was determined using either test bolus (n=30) or bolus tracking (n=30). Test bolus was performed using an additional 20 ml Iomeprol 400 injected with a rate of 4 ml/s during acquisition of a series of dynamic low-dose monitoring scans followed by injection of a saline bolus of 20 ml using the same flow rate. For DECT angiography of the lungs 100ml Iomeprol 400 was injected with an injection rate of 4 ml/s followed by a saline chaser of 20 ml using the same flow rate. Attenuation profiles of different vascular segments (pulmonary arteries, pulmonary parenchyma, aorta, all 4 heart chambers) were measured to evaluate the timing techniques. Overall image quality of dual-energy "perfusion" maps and virtual 120 kV CTA images was evaluated by two radiologists regarding the present of artifacts. In all patients an adequate and homogeneous contrast enhancement of more than 400 Hounsfield units (HU) was achieved in the different vascular districts. No statistically significant difference between test bolus and bolus tracking was found regarding vessel attenuation or overall image quality. A homogeneous opacification of the different vascular territories and the pulmonary parenchyma as well as a sufficient image quality can be achieved with either bolus tracking or test bolus techniques.European journal of radiology 01/2012; 81(1):132-8. DOI:10.1016/j.ejrad.2010.06.023 · 2.16 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Background Optimal contrast enhancement is crucial for the detection of coronary artery stenoses and atherosclerotic changes in coronary CT angiography (CTA).PurposeTo demonstrate the feasibility of using the cardiac output (CO) obtained from the test bolus injection data-set (COtest) as a factor in contrast injection rate revision of the following coronary CTA.Material and Methods The test bolus injection data-sets of 52 consecutive coronary CTAs were examined. COtest was calculated from the test bolus data-set. Aortic peak enhancement (APE) was measured on the following coronary CTA. We simulated the APE at a fixed contrast injection rate of 4 mL/s (simAPE) in each patient.ResultsThe ranges of COtest and simAPE were 2.82-7.56 L/min and 194-527 Hounsfield Units, respectively. There was a significant negative correlation (R = -0.802, P < 0.001) between simAPE and COtest.ConclusionCOtest can be used for injection rate revision on coronary CTA.Acta Radiologica 09/2012; 53(10). DOI:10.1258/ar.2012.120276 · 1.35 Impact Factor