sábado, 21 de maio de 2011

Desenvolvimento em Sequências de pulso

Segue um artigo interessante mostrando como é vasto o campo para desenvolvimento em ressonância magnética. O último post da seção de MR havia mostrado a utilidade dos pulsos de inversão para supressão de matéria branca e CSF na investigação de esclerose múltipla. Este artigo mostra a possível utilização de quatro pulsos de inversão antes da aquisição da imagem para angiorressonância das artérias ilíacas.

Noncontrast MR angiography for comprehensive assessment of abdominopelvic arteries using quadruple inversion-recovery preconditioning and 3D balanced steady-state free precession imaging: "

Abstract

Purpose:

To develop a noncontrast magnetic resonance angiography (MRA) method for comprehensive evaluation of abdominopelvic arteries in a single 3D acquisition.

Materials and Methods:

A noncontrast MRA (NC MRA) pulse sequence was developed using four inversion-recovery (IR) pulses and 3D balanced steady-state free precession (b-SSFP) readout to provide arterial imaging from renal to external iliac arteries. Respiratory triggered, high spatial resolution (1.3 × 1.3 × 1.7 mm3) noncontrast angiograms were obtained in seven volunteers and ten patients referred for gadolinium-enhanced MRA (CE MRA). Images were assessed for diagnostic quality by two radiologists. Quantitative measurements of arterial signal contrast were also performed.

Results:

NC MRA imaging was successfully completed in all subjects in 7.0 ± 2.3 minutes. In controls, image quality of NC MRA averaged 2.79 ± 0.39 on a scale of 0–3, where 3 is maximum. Image quality of NC MRA (2.65 ± 0.41) was comparable to that of CE MRA (2.9 ± 0.32) in all patients. Contrast ratio measurements in patients demonstrated that NC MRA provides arterial contrast comparable to source CE MRA images with adequate venous and excellent background tissue suppression.

Conclusion:

The proposed noncontrast MRA pulse sequence provides high-quality visualization of abdominopelvic arteries within clinically feasible scan times. J. Magn. Reson. Imaging 2011;33:1430–1439. © 2011 Wiley-Liss, Inc.

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