Optimal injection rate and catheter size for brain perfusion computed tomography using non-ionic contrast medium in clinically normal Beagles

Abstract

OBJECTIVE To evaluate the effects of contrast medium injection rates and intravenous injection catheter sizes on the time-density curve (TDC) of brain perfusion computed tomography (PCT) images in clinically normal Beagles and provide a reference range for the perfusion parameters for clinical application of PCT in veterinary medicine. ANIMALS 5 healthy, sexually intact male Beagles. PROCEDURES All dogs underwent general anesthesia for PCT. Contrast medium (350 mg I/kg) was injected at 3 different injection rates (2, 3, and 4 mL/second) and with 2 sizes of an intravenous catheter (20-gauge and 24-gauge). The rostral cerebral artery and dorsal sagittal sinus were selected as the regions of interest of the TDC. Initiation time of arterial inflow (ta), venous outflow (tv), peak time of arterial enhancement (Tap), and the peak time of venous enhancement (Tvp), were measured, and the difference between Tap and tv (Tap-tv) and between Tap and ta (Tap-ta) was calculated. RESULTS Both Tap-tv and Tap-ta were significantly (P < .05) shorter at the rate of 3 mL/second than at 2 mL/second with the 24-gauge catheter. However, there was no significant difference according to catheter sizes. Particularly, a 4 mL/second injection rate using a 24-gauge catheter mostly resulted in contrast medium leakage and catheter rupture. CLINICAL RELEVANCE: CONTRAST MEDIUM INJECTION At a rate of 3 mL/second and with a 24-gauge catheter ensures optimal image acquisition and stable contrast medium injection in brain PCT for small dogs. PCT may be useful for diagnosing cerebrovascular events and hemodynamic changes in small dogs.

Comparison of computed tomography perfusion and magnetic resonance dynamic susceptibility contrast perfusion-weighted imaging in canine brain

“…In CTP, after a single injection of an iodine contrast medium, the change in pixel enhancement of the cerebral artery and vein can be measured in Hounsfield unit (HU) by placing regions of interest (ROIs) over the middle cerebral artery, dorsal sagittal sinus, and brain tissue and generating the time-density curve (TDC) (6,7). Then, a perfusion map can be obtained from the TDC, and the quantitative perfusion parameters including cerebral blood volume (CBV), cerebral blood flow (CBF), time to peak of tissue enhancement (TTP), and mean transit time (MTT) can be measured (8,9). MR perfusion can be performed using three techniques including DSC, dynamic contrast-enhanced (DCE), and arterial spin labeling (ASL) and perfusion parameters such as CBV, CBF, TTP, MTT, negative enhancement integral (NEI), and k-trans can be derived.…”