Objective—To determine computed tomography (CT) delay times by use of a sequential scan and identify the normal enhancement pattern in each phase of a triphasic CT scan of the kidneys in dogs.
Animals—14 healthy Beagles.
Procedures—A sequential CT scan was used for investigating delay time, and a triphasic helical CT scan was used for identifying the normal enhancement pattern and determining Hounsfield unit values in the kidneys of dogs.
Results—In the cine scan (single-slice dynamic scan), the optimal delay times were 10 seconds in the corticomedullary phase and 44 seconds in the nephrographic phase, after contrast medium injection. By use of triphasic CT images, Hounsfield unit values were acquired in each phase.
Conclusions and Clinical Relevance—Triphasic CT of the kidneys in clinically normal dogs was established by acquisition of delay times in a cine scan and may become an important imaging modality in the diagnosis of renal diseases and in treatment planning in dogs.
Objective—To evaluate the effects of thiopental, propofol, and etomidate on glomerular filtration rate (GFR) measured by the use of dynamic computed tomography in dogs.
Animals—17 healthy Beagles.
Procedures—Dogs were randomly assigned to receive 2 mg of etomidate/kg (n = 5), 6 mg of propofol/kg (7), or 15 mg of thiopental/kg (5) during induction of anesthesia; anesthesia was subsequently maintained by isoflurane evaporated in 100% oxygen. A 1 mL/kg dosage of a 300 mg/mL solution of iohexol was administered at a rate of 3 mL/s during GFR measurement. Regions of interest of the right kidney were manually drawn to exclude vessels and fatty tissues and highlight the abdominal portion of the aorta. Iohexol clearance per unit volume of the kidney was calculated by use of Patlak plot analysis.
Results—Mean ± SD weight-adjusted GFR of the right kidney after induction of anesthesia with thiopental, propofol, and etomidate was 2.04 ± 0.36 mL/min/kg, 2.06 ± 0.29 mL/min/kg, and 2.14 ± 0.43 mL/min/kg, respectively. However, no significant differences in weight-adjusted GFR were detected among the treatment groups.
Conclusions and Clinical Relevance—Results obtained for the measurement of GFR in anesthetized dogs after anesthetic induction with etomidate, propofol, or thiopental and maintenance with isoflurane did not differ significantly. Therefore, etomidate, propofol, or thiopental can be used in anesthesia-induction protocols that involve the use of isoflurane for maintenance of anesthesia without adversely affecting GFR measurements obtained by the use of dynamic computed tomography in dogs.
Objective—To compare echocardiographic measurements of left ventricular (LV) volume obtained via a modified Simpson or Teichholz method with those obtained via dual-source CT (DSCT).
Animals—7 healthy Beagles.
Procedures—Each dog was anesthetized for DSCT; LV volume was determined from contrast-enhanced images of the LV lumen during all phases of contraction. Echocardiography was performed with dogs awake and anesthetized. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume, and ejection fraction were measured via a modified Simpson method and Teichholz method. Each dog was anesthetized twice with a 1-week interval between anesthetic sessions.
Results—Results obtained while dogs were anesthetized revealed that the modified Simpson method underestimated LV volume (mean ± SD EDV, 24.82 ± 2.38 mL; ESV, 12.24 ± 1.77 mL), compared with that estimated by the Teichholz method (EDV, 32.57 ± 2.85 mL; ESV, 14.87 ± 2.09 mL) or DSCT (EDV, 34.14 ± 1.57 mL; ESV, 16.71 ± 0.76 mL). Ejection fraction (modified Simpson method, 48.53% ± 4.24%; Teichholz method, 54.33% ± 4.26%; DSCT, 51.00% ± 2.71%) differed significantly among the 3 methods. Echocardiographic results obtained while dogs were awake revealed that EDV, ESV, and stroke volume differed significantly between the modified Simpson and Teichholz methods.
Conclusions and Clinical Relevance—LV volume determined via the Teichholz method was more similar to that determined via DSCT than was the LV volume determined via the modified Simpson method. The modified Simpson method underestimated LV volume, compared with that obtained via the Teichholz method, in both anesthetized and awake dogs.