The influence of stimulated echoes on contrast in fast spin-echo imaging

• Published in: Magnetic resonance imaging Vol. 14; no. 4; pp. 419 - 428
• Main Authors: Williams, C.F.M., Redpath, T.W., Smith, F.W.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 1996; Elsevier Science
• Subjects: Biological and medical sciences; Computer Simulation; Fast spin-echo imaging; Hemorrhage; Image Enhancement; Investigative techniques, diagnostic techniques (general aspects); Magnetic Resonance Imaging - methods; Medical sciences; Nervous system; Phantoms, Imaging; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Slice profile; Stimulated echoes; Sulfates; Tissue contrast; Stimulated echoes; Fast spin-echo imaging; Hemorrhage; Tissue contrast; Slice profile; Vascular disease; Human; Tissue; Nervous system diseases; Cerebral hemorrhage; Central nervous system disease; Cardiovascular disease; Spin echo; Contrast; Cerebrovascular disease; Cerebral disorder
• ISSN: 0730-725X; 1873-5894
• DOI: 10.1016/0730-725X(95)02110-F

Tissue contrast obtained using fast spin-echo (FSE) and conventional spin-echo (SE) sequences is not identical and a number of mechanisms are thought to contribute to these contrast differences. The effect of stimulated echoes has previously been apparently ruled out as a contributing mechanism. Signal-to-noise ratios of single-slice matched FSE and conventional SE sequences were compared in aqueous solutions of CuSO
4, Cr
2(SO
4)
3 and MnSO
4 with various
T
1 and
T
2 values. Enhancement of the FSE signal was observed in short
T
2 solutions and the effect was greater in samples where the
T
1 to
T
2 ratio was high. Reducing the refocusing pulse flip angle to increase the contribution from stimulated echoes also resulted in slightly increased enhancement. Experimental results were verified by computer simulations. Our results show that stimulated echoes do contribute to the contrast differences between FSE and conventional SE images and may be significant in the imaging of brain hemorrhage.