𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Projection flow imaging by bolus tracking using stimulated echoes

✍ Scribed by Thomas K. F. Foo; William H. Perman; Colin S. O. Poon; Jack T. Cusma; John C. Sandstrom

Publisher
John Wiley and Sons
Year
1989
Tongue
English
Weight
1010 KB
Volume
9
Category
Article
ISSN
0740-3194

No coin nor oath required. For personal study only.

✦ Synopsis

Previous investigators have employed the concept of bolus tracking using either spin echoes or gradient echoes. In this paper we introduce two methods ofbolus tracking using planar-and volume-selective stimulated echoes. The planar method employs a selective 90" rf pulse which tags all spins in a particular plane. At a time 7, later, a nonselective 90" rf pulse is employed, followed aAer a time i2, by another nonselective rfpulse. Only spins which experience all three rf pulses form a stimulated echo at time i I after the third rfpulse. A balanced pair offlow-compensated dephasing (crusher) gradients further ensures that the stimulated echo is due only to the effect of all three rfpulses while minimizing flow dephasing. The first part of this gradient pair is applied after the initial rf pulse in the first i1 period to dephase the tagged spins. The second part of this gradient pair is applied after the third rf pulse to rephase the spins. Since the plane of the excited slice is orthogonal to the readout direction, flowing spins are imaged in an angiographic manner as they inove away from the excited slice. A modification to this basic sequence excites only a small volume. In this manner, the suppression of stationary spins is effected by volume-selective excitation. In both the planar-and the volume-selective techniques, the excited spins undergo TI and Tz relaxation during the i1 period but only TI relaxation in the i2 period. In blood, where TI is much greater than T 2 , keeping 7 as short as possible minimizes signal loss due to Tz dephasing. These methods demonstrate increased sensitivity compared to similar bolus tracking methods using either spin echoes or gradient echoes. 0 1989 Academic Press. Inc.

📜 SIMILAR VOLUMES

Velocity imaging of slow coherent flows
Velocity imaging of slow coherent flows using stimulated echoes
✍ A. Caprihan; R. H. Griffey; E. Fukushima 📂 Article 📅 1990 🏛 John Wiley and Sons 🌐 English ⚖ 480 KB

## Abstract We measure the velocity distribution of slow fluid flow in model systems using stimulated echoes and velocity phase encoding. We show velocity images of slow coherent flow with velocities of the order of 0.1 mm/s which is slower than can be obtained by the bolus‐tracking method. The edd

Cerebral hemodynamic changes measured by
Cerebral hemodynamic changes measured by gradient-echo or spin-echo bolus tracking and its correlation to changes in ICA blood flow measured by phase-mapping MRI
✍ Jacob R. Marstrand; Egill Rostrup; Sverre Rosenbaum; Ellen Garde; Henrik B.W. La 📂 Article 📅 2001 🏛 John Wiley and Sons 🌐 English ⚖ 237 KB

## Abstract Changes in cerebral blood flow (CBF) induced by Acetazolamide (ACZ) were measured using dynamic susceptibility contrast MRI (DSC‐MRI) with both spin echo (SE) EPI and gradient echo (GE) EPI, and related to changes in internal carotid artery (ICA) flow measured by phase‐mapping. Also exa

MR imaging of anisotropic and restricted
MR imaging of anisotropic and restricted diffusion by simultaneous use of spin and stimulated echoes
✍ Christopher H. Sotak; Limin Li 📂 Article 📅 1992 🏛 John Wiley and Sons 🌐 English ⚖ 696 KB

## Abstract A new magnetic resonance imaging technique for evaluating anisotropic and restricted diffusion effects in a single experiment is described. The method is based on a pulse sequence that simultaneously excites a spin echo (SE) and a stimulated echo (STE) and contains two pairs of diffusio

Evaluation of intraportal venous flow di
Evaluation of intraportal venous flow distribution by unenhanced MR angiography using three-dimensional fast spin-echo with a selective tagging pulse: Efficacy of subtraction of tag-on and tag-off images acquired during a single breath-hold
✍ Katsuyoshi Ito; Ayame Shimizu; Toshinobu Tsukuda; Katsumi Sasaki; Masahiro Tanab 📂 Article 📅 2009 🏛 John Wiley and Sons 🌐 English ⚖ 414 KB

## Abstract ## Purpose To evaluate the efficacy of subtracted MR images from two sets of unenhanced three‐dimensional (3D) MR angiography data (tag‐on and tag‐off images) acquired simultaneously during a single breath‐hold in assessing the intraportal venous flow distribution to the distal branche