The influence of injection rate and time resolution on dynamic contrast-enhanced MR imaging of glioma / 实用放射学杂志

Objective To explore the influence of contrast agent injection rate and sequence time resolution on the dynamic contrast-enhanced MR iamging of brain glioma.Methods Fifty eight cases with suspected cerebral glioma were scanned on a Verio 3.0T MRI with the regular head sequences and DCE sequences.All the cases were divided into two groups.There were 41 cases in the regular group in which the injection rate was 3 mL/s and the time resolution was above 5.36 s.Another 1 7 cases were in the optimal group in which the injection rate was 4 mL/s and the time resolution was about 4 s.The DCE images of two groups were Postprocessed by the Tofts model analysis.The curve shape of AIF were evaluated and divided in to the excellent or the secondary level.Chi-square test was used to compare the results of two groups.Results The curve shape of optimal group was much better than that of regular group(P<0.05).Conclusion Speeding up the injection rate and the time resolution of DCE sequences would improve the image quality of DCE MRI of glioma.

Hepatic Arterial Phase on Gadoxetic Acid-Enhanced Liver MR Imaging: A Randomized Comparison of 0.5 mL/s and 1 mL/s Injection Rates

OBJECTIVE: To compare gadoxetic acid injection rates of 0.5 mL/s and 1 mL/s for hepatic arterial-phase magnetic resonance (MR) imaging. MATERIALS AND METHODS: In this prospective study, 101 consecutive patients with suspected focal liver lesions were included and randomly divided into two groups. Each group underwent dynamic liver MR imaging using a 3.0-T scanner after an intravenous injection of gadoxetic acid at rates of either 0.5 mL/s (n = 50) or 1 mL/s (n = 51). Arterial phase images were analyzed after blinding the injection rates. The signal-to-noise ratios (SNRs) of the liver, aorta, portal vein, hepatic vein, spleen, and pancreas were measured. The contrast-to-noise ratios (CNRs) of the hepatocellular carcinomas (HCC) were calculated. Finally, two experienced radiologists were independently asked to identify, if any, HCCs in the liver on the images and score the image quality in terms of the presence of artifacts and the proper enhancement of the liver, aorta, portal vein, hepatic vein, hepatic artery, spleen, pancreas, and kidney. RESULTS: The SNRs were not significantly different between the groups (p = 0.233-0.965). The CNRs of the HCCs were not significantly different (p = 0.597). The sensitivity for HCC detection and the image quality scores were not significantly different between the two injection rates (p = 0.082-1.000). CONCLUSION: Image quality and sensitivity for hepatic HCCs of arterial-phase gadoxetic acid-enhanced MR were not significantly improved by reducing the contrast injection rate to 0.5 mL/s compared with 1 mL/s.

The effect of injection rate on etomidate-induced myoclonus / 대한마취과학회지

BACKGROUND: Etomidate frequently causes myoclonus. Since the myoclonus is caused by a transient disequilibrium due to etomidate exposure in the CNS, we hypothesized that a slow rate of injection of the drug may decrease the incidence of myoclonus. We conducted a prospective randomized study to compare the effect of two different types of the etomidate injection rate on the incidence and severity of myoclonus. METHODS: Fifty patients were randomly assigned to the fast-injection group (group F) or slow-injection group (group S): Group F patients received etomidate (0.3 mg/kg) over ten seconds. The same dose was administered over two minutes for group S patients. The response to the injection of etomidate was graded on a four-point scale in a blinded manner. The time to loss of consciousness (LOC) was also recorded. RESULTS: The incidence of myoclonus was significantly lower (P < 0.001) in group S patients; 84% and 28% in group F and group S patients, respectively. The myoclonus was also significantly less severe in group S patients (P < 0.001). The time to LOC was significantly longer in group S patients (106 +/- 22 sec) than that of group F patients (49 +/- 18 sec, P < 0.001). CONCLUSIONS: With same dose, a slower rate of injection resulted in a lower incidence of myoclonus and can effectively reduce myoclonus without the use of a pretreatment agent.

Influence of injection rate of isobaric ropivacaine on spinal anesthesia / 上海第二医科大学学报

0.05).Conclusion There may be no significant difference in sensory block,motor block and prevalence of adverse effects between injection rates of 0.27 mL/s and 0.04 mL/s in spinal anesthesia with 20 mg isobaric ropivacaine.

An Experimental Study about Contrast Medium Injection Rate and Dose in Cerebral CT Perfusion Imaging / 实用放射学杂志

Objective To investigate the suitable injection rate and dose in multi-slice CT perfusion imaging.Methods Randomized block design was adopted in this study.The treatment factor-contrast medium injection rate was classified into 3,4,5,6 and 8 ml/s;thesubjects were divided into 5 blocks grouped by contrast medium injection dose: 0.5,0.75,1,1.25 and 1.5 ml/kg.25 Beagles wererandomly enrolled to undergo cerebral CT perfusion imaging.After post processing,time to peak(TTP) and rise value(RV) were measured in superior sagital venous.Results Injection rate had a significant effect on TTP of superior sagital venous.There was no significant difference among group 5,6 and 8 ml/s.Compared with 8 ml/s,TTP of superior sagital venous was prolonged when injection rate 3,4 ml/swere adopted.Injection dose had a significant effect on RV of superior sagital venous.There was no significant difference among group 1,1.25 and 1.5 ml/kg.In comparison with 1 ml/kg,RV of superior sagital venous was prolonged when injection dose 0.5 and 0.75 ml/kg were adopted.Conclusion The quality of cerebral CT perfusion imaging is well enough even injection rate as low as 5 ml/s or injection dose as few as 1 ml/kg.