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Comparative Analysis of Blood T 2 Values Measured by T 2 -TRIR and TRUST.

Authors :: Baas KPA
Coolen BF
Petersen ET
Biemond BJ
Strijkers GJ
Nederveen AJ
Source :: Journal of magnetic resonance imaging : JMRI [J Magn Reson Imaging] 2022 Aug; Vol. 56 (2), pp. 516-526. Date of Electronic Publication: 2022 Jan 25.
Publication Year :: 2022
Abstract: Background: Venous blood oxygenation (Yv), which can be derived from venous blood T <subscript>2</subscript> (T <subscript>2</subscript> b), combined with oxygen-extraction fraction (OEF) and cerebral metabolic rate of oxygen, is considered indicative for tissue viability and brain functioning and frequently assessed in patients with sickle cell disease. Recently, T <subscript>2</subscript> -Prepared-Blood-Relaxation-Imaging-with-Inversion-Recovery (T <subscript>2</subscript> -TRIR) was introduced allowing for simultaneous measurements of blood T <subscript>2</subscript> and T <subscript>1</subscript> (T <subscript>1</subscript> b), potentially improving Yv estimation by overcoming the need to estimate hematocrit. Purpose: To optimize and compare T <subscript>2</subscript> -TRIR with T <subscript>2</subscript> -relaxation-under-spin-tagging (TRUST) sequence. Study Type: Prospective. Population: A total of 12 healthy volunteers (six female, 27 ± 3 years old) and 7 patients with sickle cell disease (five female, 32 ± 12 years old). Field Strength/sequence: 3 T; turbo field echo planar imaging (TFEPI), echo planar imaging (EPI), and fast field echo (FFE). Assessment: T <subscript>2</subscript> b, Yv, and OEF from TRUST and T <subscript>2</subscript> -TRIR were compared and T <subscript>2</subscript> -TRIR-derived T <subscript>1</subscript> b was assessed. Within- and between-session repeatability was quantified in the controls, whereas sensitivity to hemodynamic changes after acetazolamide (ACZ) administration was assessed in the patients. Statistical Tests: Shapiro-Wilk, one-sample and paired-sample t-test, repeated measures ANOVA, mixed linear model, Bland-Altman analysis and correlation analysis. Sidak multiple-comparison correction was performed. Significance level was 0.05. Results: In controls, T <subscript>2</subscript> b from T <subscript>2</subscript> -TRIR (70 ± 11 msec) was higher compared to TRUST (60 ± 8 msec). In patients, T <subscript>2</subscript> b values were lower pre- compared to post-ACZ administration (TRUST: 80 ± 15 msec and 106 ± 23 msec and T <subscript>2</subscript> -TRIR: 95 ± 21 msec and 125 ± 36 msec). Consequently, Yv and OEF were lower and higher pre- compared to post-ACZ administration (TRUST Yv: 68% ± 7% and 77% ± 8%, T <subscript>2</subscript> -TRIR Yv: 74% ± 8% and 80% ± 6%, TRUST OEF: 30% ± 7% and 21% ± 8%, and T <subscript>2</subscript> -TRIR OEF: 25% ± 8% and 18% ± 6%). Data Conclusion: TRUST and T <subscript>2</subscript> -TRIR are reproducible, but T <subscript>2</subscript> -TRIR-derived T <subscript>2</subscript> b values are significantly higher compared to TRUST, resulting in higher Yv and lower OEF estimates. This bias might be considered when evaluating cerebral oxygen homeostasis. Evidence Level: 2 TECHNICAL EFFICACY: Stage 2. (© 2022 International Society for Magnetic Resonance in Medicine.)