Brain tumor enhancement in magnetic resonance imaging - Comparison of signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) at 1.5 versus 3 Tesla

Objective: The objective of this study was to compare the difference in lesion enhancement between 1.5 and 3 T using an extracellular gadolinium chelate in a rat brain glioma model. Methods: Five rats (CDF Fischer 344) with implanted C6/LacZ brain gliomas were evaluated using matched T1-weighted spin echo techniques and hardware configurations at 1.5 and 3 T. Serial imaging over 10 minutes after gadoteridol (ProHance) administration was performed. Contrast enhancement (CE), signal-to-noise ratios (SNR) for brain and tumor, as well as contrast-to-noise ratios (CNR) were evaluated using region-of-interest (ROI) analysis at both field strengths. All gliomas were also evaluated by histopathology. Results: CE at 3 T increased by 106% to 137% (all P < 0.05) with maximum CE occurring at 5 minutes for both 1.5 and 3 T (9.8 +/- 2.2 vs 21.1 +/- 3.5; P = 0,0004). At 3 T, SNR increased for normal brain by 66% to 76% (P < 0.01) and SNR for tumor increased by 70% to 89% (P < 0.01). CNR increased by 101% to 137% (P < 0.05) depending on the time postcontrast. The highest CNR for both 1.5 T and 3 T occurred 5 minutes after contrast (1.5 T: 9.4 +/- 1.1 vs 3 T: 20.3 +/- 2.4; P < 0.0004). Conclusion: Using a standardized animal model and matched scan techniques, this Study shows a significant benefit of 3 T compared with 1.5 T in contrast-enhanced brain tumor magnetic resonance imaging.