Spiral flow-generating tube for saline chaser improves aortic enhancement in Gd-EOB-DTPA-enhanced hepatic MRI.

OBJECTIVES: To evaluate the effect of a spiral tube on contrast enhancement in the hepatic arterial phase (HAP) of gadoxetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI). METHODS: In this retrospective study, we observed 104 patients who underwent dynamic MRI of the liver between October 2017 and December 2017. Three Gd-EOB-DTPA injection protocols were compared: (A) conventional method (undiluted Gd-EOB-DTPA, injection rate 1 ml/s, n = 36); (B) spiral dilution method (1:1 diluted Gd-EOB-DTPA with saline [off-label], injection rate 2 ml/s via spiral tube, n = 38); (C) spiral-flushed method (undiluted Gd-EOB-DTPA, injection rate 1 ml/s via spiral tube, n = 30). We regarded protocol-A as a control. The signal-to-noise ratio (SNR) of the abdominal aorta was calculated using arterial phase images. Image contrast and artefacts were evaluated by two board-certified radiologists, using a four-point scale. Statistical analyses included Dunnett's test, the Kruskal-Wallis test and the Steel test. RESULTS: The SNR of the aorta was significantly higher with protocol-C (25.4 ± 8.8) than protocol-A (20.8 ± 5.4, p = 0.01). There was no significant difference in SNR between protocols A and B (p = 0.47). The contrast score of protocol-C was significantly higher than that of protocol-A (p = 0.0019). There was no significant difference in contrast score between protocols A and B (p = 0.50). There was no significant difference in artefacts among the three protocols (p = 0.96). CONCLUSIONS: Use of a spiral tube with a slow injection protocol contributed to improved aortic contrast enhancement in the HAP of GD-EOB-DTPA-enhanced hepatic MRI. KEY POINTS: • Gadoxetic acid shows weaker arterial enhancement at recommended doses, compared with nonspecific gadolinium agents; selection of an appropriate injection protocol is important. • A spiral flow-generating tube improves the transport efficiency of the contrast media, and increases the signal-to-noise ratio of the aorta in hepatic arterial phase. • A spiral flow-generating tube does not contribute to artefact reduction in hepatic arterial phase.

Novel connecting tube for saline chaser in contrast-enhanced CT: the effect of spiral flow of saline on contrast enhancement.

OBJECTIVE: To evaluate the effect of a newly developed connecting tube, which generates a spiral flow of saline, on aortic and hepatic contrast enhancement during hepatic-arterial phase (HAP) and portal venous phase (PVP) computed tomography (CT). METHODS: Eighty patients were randomly assigned to one of two protocols: with a new or a conventional tube. The contrast material (600 mgI/kg) was delivered over 30 s; this was followed by the administration of 25 ml saline solution delivered at the same injection rate as the contrast material. Unenhanced and contrast-enhanced CT images of the upper abdomen were obtained. We calculated the changes in the CT number (∆HU) for the aorta during HAP and PVP, and for the liver during PVP. We compared ∆HU between protocols. RESULTS: The mean ∆HU for the abdominal aorta during HAP was significantly higher with the new tube protocol than with the conventional tube protocol (322 ± 53 vs. 290 ± 53, P < 0.01). There were no significant differences in the mean ∆HU for the abdominal aorta and liver during PVP between the two protocols (P > 0.05). CONCLUSION: The new connecting tube increased the effect of a saline chaser and significantly improved aortic enhancement during HAP. KEY POINTS: • Optimal administration of intravenous contrast material is essential for optimal CT quality. • A new connecting tube can generate spiral flow, which improves intravenous administration. • The new connecting tube improved aortic contrast enhancement during the hepatic-arterial phase. • The new connecting tube increased the effect of a saline chaser.

[Cerebral circulation dynamics following fasudil intravenous infusion: a CT perfusion study].

Using CT perfusion studies we evaluated changes in the cerebral circulation before and after the intravenous administration of fasudil 60 mg in 8 patients 7 to 14 days after a subarachnoid hemorrhage. The mean duration to the peak of the time-density curve and the average peak value did not change. In areas with cerebral blood perfusion (CBP) less than 40 ml/100 g/min, the CBP increased from 34.4 +/- 4.7 ml/100 g/min to 41.0 +/- 8.2 ml/100 g/min (p < 0.01) after fasudil infusion, the cerebral blood volume (CBV) rose from 2.41 +/- 0.53 ml/100 g to 2.55 +/- 0.5 ml/100 g (p < 0.05), and the mean transit time (MTT) decreased from 5.09 +/- 1.13 s to 4.82 +/- 0.89 s (p < 0.05). In areas where the CBP was more than 41 ml/100 g/min, the CBP did not change (from 51.8 +/- 7.6 ml/100 g/min to 50.4 +/- 8.4 ml/100 g/min), the CBV decreased (from 2.75 +/- 0.62 ml/100 g to 2.67 +/- 0.55 ml/100 g, p < 0.05), and the MTT did not change (from 3.80 +/- 0.76 s to 3.77 +/- 0.72 s). These results suggest that intravenous infusion of fasudil 60 mg increases cerebral blood flow and cerebral blood volume and shortens MTT in areas with decreased blood flow due to vasospasm.

[Intra-arterial administration of fasudil hydrochloride: duration of action].

Intra-arterial infusion (IA) of fasudil hydrochloride for cerebral vasospasm is performed in many institutions and is associated with few side effects. Nonetheless, as optimum dose and duration of action remain unknown, the present study aimed to clarify these variables. We performed intra-arterial injection of fasudil hydrochloride for eight patients with cerebral vasospasm 7-13 days after subarachnoid hemorrhage. Fasudil hydrochloride was administered via the internal carotid artery without selective microcatheterization, at a concentration and speed of 30 mg/20 ml/10-15 min, using a total dose of 30-60 mg. Cerebral angiography was used to measure change in blood vessel diameter at 19 points, and perfusion CT was used to detect changes in cerebral blood perfusion (CBP), cerebral blood volume (CBV), and mean transit time (MTT) at 12 hemispheres. Investigations were performed before IA, immediately after IA (post IA), and 4.5 to 6 hours later. For central vessels, (A1, M1) mean change in diameter (cm) measured pre IA, post IA, and 4.5-6 hours later was 1.2 +/- 0.68, 1.5 +/- 0.72, and 1.2 +/- 0.7, respectively. For peripheral vessels (peripheral to A1, M1, and the ophthalmic artery) change in diameter (cm) was 0.65 +/- 0.16, 0.97 +/- 0.24, and 0.71 +/- 0.24, respectively. Average CBP (m/100g/min) in the infused hemisphere at pre IA, post IA, and 4.5-6 hours later was 41.6 +/- 3.56, 46.4 +/- 5.82, 41.6 +/- 7.42, respectively. Average CBV (ml/100g) was 2.72 +/- 0.21, 2.73 +/- 0.21, 2.91 +/- 0.42, respectively and average MTT (sec) was 5.16 +/- 0.38, 4.57 +/- 0.70, 5.55 +/- 1.0, respectively. Changes in peripheral vessel diameter and in MTT were statistically significant. Therefore, when performing intra-arterial administration of fasudil hydrochloride, clinicians should be aware that vasodilator effect is less than 6 hours.