Fast measurement of blood T₁ in the human jugular vein at 3 Tesla

Current T₁ values for blood at 3T largely came from in vitro studies on animal blood or freshly drawn human blood. Measurement of blood T₁ in vivo could provide more specific information, e.g., for individuals with abnormal blood composition. Here, blood T₁ at 3T was measured rapidly (<1 min) in the internal jugular vein using a fast inversion-recovery technique in which multiple inversion time can be acquired rapidly due to constant refreshing of blood. Multishot EPI acquisition with flow compensation yielded high resolution images with minimum partial volume effect. Results showed T₁ = 1852 ± 104 msec among 24 healthy adults, a value higher than for bovine blood phantoms (1584 msec at Hct of 42%). A second finding was that of a significant difference (P < 0.01) between men and women, namely T₁ = 1780 ± 89 msec (n = 12) and T₁ = 1924 ± 58 msec (n = 12), respectively. This difference in normal subjects is tentatively explained by the difference in Hct between genders. Interestingly, however, studies done on sickle cell anemia patients with much lower Hct (23 ± 3%, n = 10) revealed similar venous blood T₁ = 1924 ± 82 msec, indicating other possible physical influences affecting blood T₁. Magn Reson Med, 2011.