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ObjectiveTo compare the effect of contrast medium iodine concentration on contrast enhancement, heart rate, and injection pressure when injected at a constant iodine delivery rate in coronary CT angiography (CTA).MethodsOne thousand twenty-four patients scheduled for coronary CTA were prospectively randomized to receive one of four contrast media: iopromide 300 mg I/ml, iohexol 350 mg I/ml, iopromide 370 mg I/ml, or iomeprol 400 mg I/ml. Contrast media were delivered at an equivalent iodine delivery rate of 2.0 g I/s. Intracoronary attenuation was measured and compared (per vessel and per segment). Heart rate before and after contrast media injection was documented. Injection pressure was recorded (n = 403) during contrast medium injection and compared between groups.ResultsIntracoronary attenuation values were similar for the different contrast groups. The mean attenuation over all segments ranged between 384 HU for 350 mg I/ml and 395 HU for 400 mg I/ml (p = 0.079). Dose-length product (p = 0.8424), signal-to-noise ratio (all p > 0.05), time to peak (p = 0.324), and changes in heart rate (p = 0.974) were comparable between groups. The peak pressures differed: 197.4 psi for 300 mg I/ml (viscosity 4.6 mPa s), 229.8 psi for 350 mg I/ml (10.4 mPa s), 216.1 psi for 370 mg I/ml (9.5 mPa s), and 243.7 psi for 400 mg I/ml (12.6 mPa s) (p < 0.0001).ConclusionIntravascular attenuation and changes in heart rate are independent of iodine concentration when contrast media are injected at the same iodine delivery rate. Differences in injection pressures are associated with the viscosity of the contrast media.Key Points• The contrast enhancement in coronary CT angiography is independent of the iodine concentration when contrast media are injected at body temperature (37 °C) with the same iodine delivery rate.• Iodine concentration does not influence the change in heart rate when contrast media are injected at identical iodine delivery rates.• For a fixed iodine delivery rate and contrast temperature, the viscosity of the contrast medium affects the injection pressure.

Objectives Contrast media (CM) extravasation is a well-known complication of CT angiography (CTA). Our prospective randomized control study aimed to assess whether a four-phasic CM administration protocol reduces the risk of extravasation compared to the routinely used three-phasic protocol in coronary CTA. Methods Patients referred to coronary CTA due to suspected coronary artery disease were included in the study. All patients received 400 mg/ml iomeprol CM injected with dual-syringe automated injector. Patients were randomized into a three-phasic injection-protocol group, with a CM bolus of 85 ml followed by 40 ml of 75%:25% saline/CM mixture and 30 ml saline chaser bolus; and a four-phasic injection-protocol group, with a saline pacer bolus of 10 ml injected at a lower flow rate before the three-phasic protocol. Results 2,445 consecutive patients were enrolled (mean age 60.6 ± 12.1 years; females 43.6%). Overall rate of extravasation was 0.9% (23/2,445): 1.4% (17/1,229) in the three-phasic group and 0.5% (6/1,216) in the four-phasic group (p = 0.034). Conclusions Four-phasic CM administration protocol is easy to implement in the clinical routine at no extra cost. The extravasation rate is reduced by 65% with the application of the four-phasic protocol compared to the three-phasic protocol in coronary CTA. Key Points • Four-phasic CM injection-protocol reduces extravasation rate by 65% compared to three-phasic. • The saline pacer bolus substantially reduces the risk of CM extravasation. • The implementation of four-phasic injection-protocol is at no cost.

Purpose To prospectively compare two different approaches for estimating the amount of intravenous contrast media (CM) needed for multiphasic MDCT of the liver in obese patients. Materials and methods This single-center, HIPAA-compliant prospective study was approved by our Institutional Review Board. Ninety-six patients (55 men, 41 women), with a total of 42 hypovascular liver lesions, underwent MDCT of the liver. The amount of contrast medium injected was computed according to the patient’s lean body weight which was estimated using either a bioimpedance device (Group A) or the James formula (Group B). The following variables were compared between the two groups: the amount of contrast medium injected (in grams of Iodine, gI), the contrast enhancement index (CEI) and the lesion-to-liver contrast-to-noise ratio. Results Protocols A and B yielded significant differences in the amount of CM injected (mean values 41.9 ± 4.41 gI in Group A vs. 35.9 ± 5.75 gI in Group B; P  = 0.021). The mean CEI value and lesion-to-liver contrast-to-noise ratio measured on the portal phase were significantly higher with protocol A than with protocol B ( P  < 0.05). Conclusions Our study shows that the adoption of a bioimpedance device in obese patients improves liver parenchymal enhancement and lesion conspicuity.

Objectives The objective of this study is to compare the palatability of iopamidol and iohexol. Methods This was a blinded and randomized trial in which fifty healthy subjects taste tested iopamidol (Isovue, Bracco Diagnostics), iohexol (Omnipaque, GE Healthcare), diatrizoate meglumine and diatrizoate sodium solution (Gastrografin, Bracco Diagnostics), and barium sulfate suspension 2.1% w/v, 2.0% w/w (READI-CAT2, E-Z-EM). Participants scored palatability on a continuous scale from 0 to 40 (0 = intolerable, 10 = unpleasant but tolerable, 20 = neutral, 30 = kind of like, 40 = strongly like). Results Mean scores (SD/SEM) for the contrast agents ( n  = 50) were iopamidol = 21.0 (8.4/1.2); iohexol = 21.8 (7.1/1.0); Gastrografin = 16.8 (9.6/1.4); and barium = 23.7 (9.1/1.3). One-way ANOVA equality of means test shows rejection of the hypothesis that the means are equal ( F * = 6.550, p  = .000). Post hoc testing demonstrates Gastrografin to be significantly less preferred to barium ( p  = .000) and iohexol ( p  = .012). No difference was found between iopamidol and iohexol ( p  = .959). One-way ANOVA equality of means test of just iopamidol, iohexol, and barium does not reject the hypothesis that means are equal ( F * = 1.778 and p  = .174). Conclusion There is no significant difference in palatability between iopamidol and iohexol, supporting the use of iopamidol as a viable alternative to iohexol as an oral contrast agent.

PurposeTo compare the nephrotoxic effects of iodixanol and iopamidol in patients undergoing peripheral angiography.MethodsPatients scheduled for peripheral angiography were randomly assigned to the iodixanol group (n = 463) and iopamidol group (n = 458). The primary endpoint was the incidence of contrast associated acute kidney injury (CA-AKI), which was defined as an increase ≥ 25% or ≥ 44.2 µmol/l (0.5 mg/dl) in serum creatinine (SCr) from baseline within 72 h after receiving contrast media (CM). The secondary endpoints were the mean peak SCr increase within 72 h after receiving CM and major adverse renal events (SCr increased by two times after 30 days, the need for dialysis treatment, rehospitalization for acute renal failure, or kidney-related death) during hospitalization and within 30 day postdischarge.ResultsThe incidence of CA-AKI did not differ significantly between the iodixanol group and iopamidol group (18.1% vs. 16.8%; p = 0.595). There was no significant difference in the mean peak SCr increase between the iodixanol group and iopamidol group (10.4 ± 13.0 vs. 10.6 ± 14.3 µmol/l, p = 0.919). There were four patients [1 (0.2%) patient in the iodixanol group and 1 (0.7%) patients in the iopamidol group, p = 0.609] with doubling of SCr; no other adverse renal events were observed.ConclusionsOur data showed that the nephrotoxicity of iodixanol was comparable with that of iopamidol in patients undergoing peripheral angiography.

The current perception of using contrast-enhanced CT (CECT) for attenuation correction (AC) is that of caution, as it might lead to erroneously elevated (18)F-FDG uptake on the PET scan. This study evaluates in vivo whether an intravenous iodinated contrast agent produces a significant AC artifact in the level of standardized uptake value (SUV) changes in PET/CT. Fifty-four patients referred for whole-body (WB) PET/CT scans were enrolled and subdivided into 2 groups. In part I, 26 patients had a single WB PET scan that was corrected for attenuation using noncontrast and intravenous CECT obtained before and after the emission data, respectively. The final PET images were compared for any visual and SUV maximum (SUV(max)) measurement difference. This allowed analysis of the compatibility of the scaling processes between the 2 different CTs and the PET. The SUV(max) values were obtained from ascending aorta, upper lung, femoral head, iliopsoas muscle, spleen, liver, and the site of pathology (total, 193 regions). Part II addressed whether intravenous contrast also influenced the PET emission data. For that purpose, the remaining 28 patients underwent a limited plain CT scan from lung base to lower liver edge, followed by a 1-bed PET scan of the same region and then a WB intravenous contrast CT scan in tandem with a WB PET scan. SUV(max) values were obtained at the lung base, liver, spleen, T11 or T12 vertebra, and paraspinal muscle (total, 135 regions). The data obtained from pre- and post-intravenous contrast PET scans were analyzed as in part I. There was no statistically significant elevation of the SUV level in the measured anatomic sites as a whole (part I: mean SUV(max) difference = 0.06, P > 0.05; Part II: mean SUV(max) difference = -0.02, P > 0.05). However, statistically significant results as a group (mean SUV(max) difference = 0.26, P < 0.05)--albeit considered to be clinically insignificant--were observed for areas of pathology in the part I study. No abnormal focal increased (18)F-FDG activity was detected as a result of the intravenous contrast in both parts of this examination. No statistically or clinically significant spuriously elevated SUV level that might potentially interfere with the diagnostic value of PET/CT was identified as a result of the application of intravenous iodinated contrast.

Objective To compare tumour-to-liver contrast (TLC) of C-arm CT during hepatic arteriography (CACTHA) acquired using three protocols in patients with HCC. Methods This prospective study was IRB approved and informed consent was obtained from each patient. Twenty-nine patients (mean age, 68 ± 7 years; 27 men) with 55 HCCs (mean diameter, 2.6 ± 1.5 cm) underwent three different CACTHA protocols in random order before chemoembolisation. Contrast medium (100 mg iodine/ml) was injected into the common hepatic artery (flow rate 4 ml/s). The imaging delay for the start of the CACTHA examination was 4 s (protocol A), 8 s (protocol B) and 12 s (protocol C) (total amount of injected contrast medium: 48 ml, 64 ml, 80 ml). TLC was measured by placing regions of interest (ROIs) in the HCC and liver parenchyma. Mixed model ANOVAs and Bonferroni corrected post hoc tests were used for statistical analysis. Results Mean values for TLC were 132 ± 3.3 HU, 186 ± 5.8 HU and 168 ± 2.8 HU for protocols A, B and C. Protocol B provided significantly higher TLC than protocols A and C ( p  < 0.001). Conclusion TLC was significantly higher using an imaging delay of 8 s compared with a delay of 4 or 12 s. Key Points • C-arm cone-beam CT (CACT) angiography offers additional information during hepatic intervention. • CACT hepatic arteriography tumour-to-liver contrast is highest with an 8-s delay. • An 8-s delay is recommended for early arterial phase CACTHA for hepatocelullar carcinoma.

Background and ObjectivesIntravascular (IV) injection of local anesthetics is a potential cause of false-negative results after lumbar medial branch nerve blockade (L-MBB) performed to diagnose facetogenic back pain. The aim of the present study was to identify the relationship between the needle type and the incidence of IV injection in patients undergoing L-MBB using fluoroscopy with digital subtraction imaging (DSI).MethodsIn this prospective randomized study, we compared the incidence of IV uptake of contrast medium using the Quincke needle and Whitacre needle under real-time DSI during L-MBB. Clinical and demographic factors associated with the occurrence of IV uptake were also investigated.ResultsIn total, 126 patients were randomized into the Quincke needle group (n = 62) and Whitacre needle group (n = 64). Intravascular uptake of contrast medium was observed in 66 (9.8%) of 671 L-MBB procedures under DSI. The incidence of IV uptake was 13.9% (47/338) using the Quincke needle and 5.7% (19/333) using the Whitacre needle. In the multivariate generalized estimating equations analysis, use of a Quincke needle was related to positive IV injection at a 1.898-fold higher rate than was use of a Whitacre needle (95% confidence interval, 1.025–3.516) and a positive aspiration test predicted IV injection at a 21.735-fold higher rate (95% confidence interval, 11.996–52.258).ConclusionsLumbar medial branch nerve blockade using the Quincke needle was associated with a 1.9-fold higher rate of IV injection than was L-MBB using the Whitacre needle under DSI. Although further study is needed to confirm the clinical efficacy, Whitacre needles can be considered to reduce the risk of IV injection during L-MBB.

The purpose of this study was compare embolization of the gastroduodenal artery (GDA) using standard pushable coils with the Interlock detachable coil (IDC), a novel fibered mechanically detachable long microcoil, in patients scheduled for selective internal radiotherapy (SIRT). Fifty patients (31 male and 19 female; median age 66.6 ± 8.1 years) were prospectively randomized for embolization using either standard coils or IDCs. Procedure time, radiation dose, number of embolization devices, complications, and durability of vessel occlusion at follow-up angiography were recorded. The procedures differed significantly in time (14:32 ± 5:56 min for standard coils vs . 2:13 ± 1:04 min for IDCs; p  < 0.001); radiation dose for coil deployment (2479 ± 1237 cGycm² for standard coils vs . 275 ± 268 cGycm² for IDCs; p  < 0.001); and vessel occlusion (17:18 ± 6:39 min for standard coils vs . 11:19 ± 7:54 min for IDCs; p  = 0.002). A mean of 6.2 ± 1.8 coils ( n  = 27) were used in the standard coil group, and 1.3 ± 0.9 coils ( p  < 0.0001) were used in the IDC group ( n  = 23) because additional pushable coils were required to achieve GDA occlusion in 4 patients. In 2 patients, the IDC could not be deployed through a Soft-VU catheter. One standard coil dislodged in the hepatic artery and was retrieved. Vessel reperfusion was noted in only 1 patient in the standard coil group. Controlled embolization of the GDA with fibered IDCs was achieved more rapidly than with pushable coils. However, vessel occlusion may not be obtained using a single device only, and the use of sharply angled guiding catheters hampered coil pushability.

Purpose We aimed to examine the therapeutic efficacy of ethanolamine oleate iopamidol (EOI) as an embolic material for percutaneous transhepatic portal embolization (PTPE). Methods Eighty-two patients with liver tumors were treated with PTPE. Fifty-eight patients had hepatocellular carcinomas, 11 had liver metastases, and 13 had other liver tumors. A total of 55 patients (group E) were treated with 5% ethanolamine oleate after gelatin sponge administration. As a control, we evaluated 27 patients (group F) who were treated with fibrin glue and iodized oil. PTPE was mainly indicated before hepatic resection, for patients with high nontumorous volumetric resection ratios (the nontumorous volumetric resection ratio was estimated to be greater than 65% in patients with an indocyanine green retention ratio of 15 min (ICG R15) of 10% or less, and the nontumorous volumetric resection ratio was estimated to be greater than 40% in the patients with an ICG R15 of 10-20%). Results All patients were successfully treated percutaneously under local anesthesia. Balloon-occluded and ipsilateral approaches were used in 81 patients (99%) and 62 (75%) patients, respectively. The rate of insufficient embolization or recanalization was significantly lower in group E (7.3%) in comparison to group F (25.9%; p < 0.05). The volumetric resection ratios, before and after PTPE, decreased from 60 to 45% in group E and from 63 to 55% in group F. The post-PTPE resection ratio was significantly decreased in group E. Before and after PTPE, average ICG R15 values changed from 17 to 27% in group E and from 18 to 26% in group F. The complication rates in groups E and F were similar (7.3 vs. 7.4%). Conclusion EOI is a safe embolic material that can be used to induce greater liver hypertrophy, in comparison to fibrin glue, in PTPE for liver tumors.