Abstract:Computed tomography (CT) perfusion can analyze tissue perfusion and quantitative parameters, including blood flow, blood volume, and transit time. CT perfusion has been used for evaluating split renal function. However, its applicability in veterinary medicine was not validated. This study aimed to evaluate the correlation of renal blood flow (RBF) derived by maximum slope-based CT perfusion and an ultrasonic flow probe and assess the effect of the presence of a pre-existing contrast medium on CT perfusion in … Show more
“…A nonionic iodinated contrast medium (Omnipaque, GE healthcare, 350 mg I/mL, 350 mg I/kg) was administered through an intravenous catheter using a power injector according to the different conditions mentioned earlier. 18 To prevent stagnation of the contrast medium in the cerebral blood vessels, a 5-minute interval was allowed between injections across all injection rates. 22 The same procedure was repeated in the second experiment using a 20-gauge catheter.…”
Section: Brain Pctmentioning
confidence: 99%
“…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.…”
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.
“…A nonionic iodinated contrast medium (Omnipaque, GE healthcare, 350 mg I/mL, 350 mg I/kg) was administered through an intravenous catheter using a power injector according to the different conditions mentioned earlier. 18 To prevent stagnation of the contrast medium in the cerebral blood vessels, a 5-minute interval was allowed between injections across all injection rates. 22 The same procedure was repeated in the second experiment using a 20-gauge catheter.…”
Section: Brain Pctmentioning
confidence: 99%
“…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.…”
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.
“…Dynamic contrast‐enhanced computed tomography has been used in dogs, and several proof‐of‐principle studies have assessed normal tissues and tumors, and compared DCECT to 18F‐fluorodeoxyglucose positron emission tomography‐computed tomography. 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 Two studies specifically reported DCECT in nasal tumors but did not find correlation with histogenesis or survival. 33 , 39 Our objectives were (a) to assess baseline perfusion parameters in dogs with nasal tumors based on histopathological type, (b) to characterize changes in perfusion parameters with changes in tumor volume after the start of RT, and (c) to evaluate if a correlation existed of either objective 1 or objective 2 with survival.…”
Section: Introductionmentioning
confidence: 99%
“…Dynamic contrast‐enhanced computed tomography has been used in dogs, and several proof‐of‐principle studies have assessed normal tissues and tumors, and compared DCECT to 18F‐fluorodeoxyglucose positron emission tomography‐computed tomography 26‐42 . Two studies specifically reported DCECT in nasal tumors but did not find correlation with histogenesis or survival 33,39 .…”
Background
Treatment of nasal tumors in dogs is associated with high morbidity and reliable prognostic factors are lacking. Dynamic contrast‐enhanced computed tomography (DCECT) can be used to assess tumor perfusion.
Objectives
To assess perfusion parameters of nasal tumors (correlating with tumor type) before and during radiotherapy (RT) and find potential correlation with survival.
Animals
Twenty‐four client‐owned dogs with nasal tumors, including 16 epithelial tumors and 8 sarcomas.
Methods
Prospective cross‐sectional study. All dogs had baseline DCECT to assess fractional vascular volume (BV), blood flow (BF), and transit time (TT). Thirteen dogs had repeat DCECT after 12 Gy of megavoltage RT. Survival times were calculated.
Results
Median BV was 17.83 mL/100 g (range, 3.63‐66.02), median BF was 122.63 mL/100 g/minute (range, 23.65‐279.99), and median TT was 8.91 seconds (range, 4.57‐14.23). Sarcomas had a significantly lower BF than adenocarcinomas (P = .002), carcinomas (P = .01), and other carcinomas (P = .001), and significantly lower BV than adenocarcinomas (P = .03) and other carcinomas (P = .004). Significant associations were found between epithelial tumors and sarcoma for change in tumor volume (P = .01), width (P = .004), and length (P = .02) in that epithelial tumors decreased in volume whereas sarcomas increased in volume. Perfusion parameters were not correlated with survival.
Conclusions and Clinical Importance
Nasal sarcomas have lower BV and BF than nasal carcinomas, and sarcomas have a lower size reduction than carcinomas early on during RT. Baseline results and changes in perfusion parameters may not be correlated with survival.
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