PMC:7305584 / 4971-6306 JSONTXT

{"target":"http://pubannotation.org/docs/sourcedb/PMC/sourceid/7305584","sourcedb":"PMC","sourceid":"7305584","source_url":"https://www.ncbi.nlm.nih.gov/pmc/7305584","text":"Imaging studies\nThree-dimensional time-of-flight magnetic resonance angiography (TOF-MRA) of the head was obtained with the parameters: TR/TE, 21/2 ms; flip angle, 20°; FOV, 200 mm; matrix, 320 × 192; NEX, 1. The major extracranial arteries in the neck were visualized by contrast-enhanced MRA on a 3 T MR scanner (Discovery MR 750, GE Medical Systems, Milwaukee, WI, USA) using a single dose (0.1 mmol/ kg; 5–7 ml) of gadobutrol (Gd-BT-DO3A, Gadovist™, Bayer Healthcare, Leverkusen, Germany) with an injection rate of 1.5 ml/s and MR parameters of TR/TE, 4/1 ms; flip angle, 25°; FOV, 300 mm; matrix, 320 × 224; and NEX, 1. Carotid Doppler sonography was performed by the same technician with more than 10 years of experience using a Philips HD15 ultrasound system to evaluate bilateral ICA flow volume. For ICA flow volume measurement, a straight ICA segment at least 2 cm above the carotid bulb was selected with the doppler angle of incidence adjusted at or below 60 degrees. At the same site, the sample volume box was put to cover the entire vessel diameter (d). The angle-corrected time-average flow velocity (TAV) was determined over 3 to 5 complete cardiac cycles. The ICA flow volume was calculated as the product of TAV and the cross-sectional area (A) of the vessel according to the formula FV = TAV x A = TAV x [(d/2)2xπ].","divisions":[{"label":"title","span":{"begin":0,"end":15}}],"tracks":[]}