Cine-Computed Tomographic Assessment of Regional Renal Blood Flow

The new modality of cine-computed tomography was used to assess regional renal blood flow following hemorrhagic hypotension and administration of atrial natriuretic factor (ANF). As has also been established with other techniques, hypotension induced by hemorrhage caused cortical blood flow to fall from 5.3 (SD 0.8) to 2.1 (SD 1.1) ml min⁻¹g⁻¹ (p<0.005; n = 7) proportionally more than inner medullary blood flow which fell from 0.45 (SD 0.24), to 0.26 (SD 0.08) ml min⁻¹g⁻¹ (p<0.05) so that the ratio of the cortical to inner medullary blood flow decreased from 11.8 (SD 4.8) to 8.2 (SD 5.1) (p<0.01). In contrast, during natriuresis induced by ANF, cortical blood flow was unaltered (5.8, SD 1.1, vs 5.4, SD 0.9 ml min⁻¹g⁻¹; NS; n = 5) while inner medullary blood flow declined from 0.66 (SD 0.13) to 0.51 (SD 0.11) (p < 0.005) so the ratio of cortical to inner medullary blood flow increased from 8.8 (SD 1.3) to 10.9 (SD 1.7) (p<0.005). These results indicate that cine-CT appears to be an appropriate technique for demonstrating changes in distribution of intrarenal blood flow. Cine-CT may, therefore, be an attractive alternative for measuring regional renal blood flow.