Bolus tracking

Smith AM, Grandin CB, Duprez T, Mataigne F, Cosnard G. Whole brain quantitative CBF, CBV, and MTT measurements using MRI bolus tracking implementation and application to data acquired from hyperacute stroke patients. J Magn Reson Imaging 2000 12 400-410. 

Peak tissue enhancement is determined by blood volume but also depends upon cardiac output (which can vary from one patient to the other) and the volume of CA injected [10]. Furthermore, in the case of all presently available NS-CA, the intra- and extra-vascular components of enhancement cannot be evaluated separately [ 14]. It is also well known that the imaging window in CT angiography is very short and is classically compensated by the injection of high doses of NS-CA or the use of bolus-tracking software. 

Scanners equipped with a bolus tracking function can use a variable prep delay in order to minimize venous enhancement. However, this adds complexity to scanning protocols and introduces the potential for... 

Bolus tracking Accounts for different patient physiology More complex and time-consuming for the technologist scanning may not occur during peak or uniform contrast enhancement... 

As an alternative to bolus tracking, a smartscan type function can be used, in which a test bolus is administered to determine the scan delay [64]. A region of interest is selected, typically in the proximal ICA, and 10 mL of contrast is injected. This region is scanned continuously using a low mAs/kVp technique, and the prep delay is chosen as the time corresponding to... 

Paulson EK et al (1998) Helical liver CT with computer-assisted bolus-tracking technology is it possible to predict which patients wiU not achieve a threshold of enhancement Radiology 209(3) 787-792. 

Shimizu T et al (2000) Helical CT of the liver with computer-assisted bolus-tracking technology scan delay of arterial phase scanning and effect of flow rates. J Comput Assist Tomogr 24(2) 219-223. 

Calamante, F., D.G. Gadian, A. Connelly, Quantification of perfusion using bolus tracking magnetic resonance imaging in stroke assumptions, limitations, and potential implications for clinical use. Stroke, 2002. 33(4) p. 1146-51. 

When a true angiogram is needed we use a bolus tracking technique. Our protocol is to do serial low mAs scans on the vessel of interest (in the case of... 

Phase 1 CTA phase (bolus track aorta -150 HU) - diaphragm to symphisis (thin)... 

Phase 2 (CTA) - kidneys bolus track (thin) trigger at celiac artery at 150 HU (start 6 s later)... 

Bolus track the aorta at 150 HU and add 15 s prior to start of scan... 

Temporal analysis is used for bolus tracking (time-density quantification), functional maps of local perfusion parameters (of heart and brain), contrast-enhanced MRI of the breast, cardiac output calculations by measuring the volume of the left ventricle over time, multiple sclerosis lesion growth / shrinkage over time, regional cardiac wall thickness variations and local stress/strain calculations, and in fluoroscopy, e.g. the freezing of the stent in the video by cancellation of the motion of the coronary vessel. 

In addition to injection duration, variable cardiac output parameters of individual patients will have to be addressed. In principle, the two methods to assess the contrast arrival are test bolus techniques and so-called bolus tracking. Both approaches measure Carr and therefore adapt for varying cardiac output. The... 

Tao Bolus tracking in the descending aorta, Tpa bolus tracking in the pulmonary trunk ... 

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