Effect of contrast medium injection rate on computed tomography-derived renal perfusion estimates obtained with the maximum slope method in healthy Beagles

Abstract

OBJECTIVE To evaluate the effect of contrast medium injection rate on CT-derived renal perfusion estimates obtained with the maximum slope method in healthy small dogs. ANIMALS 6 healthy sexually intact male purpose-bred Beagles. PROCEDURES All dogs underwent CT perfusion analysis 3 times in a crossover design, receiving a different contrast medium injection rate (1.5, 3.0, and 4.5 mL/s) each time, with a 1-week interval between imaging sessions. All CT images were obtained at the level of the left renal hilus. The time to peak aortic enhancement (TPAE) and time to initial renal venous enhancement (TIRVE) were measured from time-attenuation curves. The renal CT perfusion estimates (blood flow and blood volume) were estimated by use of the maximum slope method, which assumes no venous outflow of contrast medium during CT perfusion analysis. RESULTS The TPAE occurred at or before the TIRVE at all injection rates. Median values of estimated blood flow and blood volume did not differ significantly among injection rates. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the assumption of no venous outflow of contrast medium during renal CT perfusion analysis with the maximum slope method was satisfied for all 3 contrast medium injection rates in the evaluated dogs. A low injection rate may be more practical than higher injection rates that require large catheters for CT perfusion analysis in small dogs such as Beagles.

Comparison of Renal Blood Flow Using Maximum Slope-Based Computed Tomography Perfusion and Ultrasound Flow Probe in Healthy Dogs

“…First, the CT perfusion for RBF was performed under general anesthesia after placing the ultrasonic flow probe, and the study design was not consistent with the clinical condition. The long duration of anesthesia could affect the CT-derived renal blood volume; however, the CT perfusion RBF values were similar to those measured immediately after inducing anesthesia using the same techniques in our previous study (17). Second, this study only included a relatively small number of dogs (n = 5) because the procedure used to measure direct RBF was invasive.…”

“…To the best of our knowledge, renal CT perfusion using the maximum slope method in dogs was evaluated in only our previous study on the effect of the contrast medium injection rate on CT perfusion (17). However, the correlation between CT perfusion analysis and true renal perfusion in dogs remains unknown.…”

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

“…One study demonstrated that rapid administration of contrast medium is required for the quantitative analysis of hepatic PCT. 17 Conversely, another study reported that even a low contrast medium injection rate of 1.5 mL/second is sufficient for the evaluation of renal perfusion. 16 The current study found that the contrast medium injection rate affected brain PCT when a 24-gauge was used.…”

“…Two studies 16,17 in veterinary medicine have also analyzed the effects of variables related to contrast medium injection on PCT; however, the results have varied. One study demonstrated that rapid administration of contrast medium is required for the quantitative analysis of hepatic PCT.…”

“…14,15 In veterinary medicine, PCT has been used in disease diagnoses that require perfusion evaluation. Several studies on variables affecting PCT have been conducted in abdominal organs such as the liver, 16 kidney, 17,18 , and pancreas. 19 In addition, studies on the diagnosis of cerebrovascular diseases that require perfusion evaluation, such as degenerative diseases 20 and brain tumors 21 have been performed.…”