High iodine concentration contrast material for noninvasive multislice computed tomography coronary angiography: iopromide 370 versus iomeprol 400

OBJECTIVE: The objective of this study was to compare intracoronary attenuation on 16-row multislice computed tomography (16-MSCT) coronary angiography using 2 contrast materials (CM) with high iodine concentration. MATERIAL AND METHODS: Forty consecutive patients (29 male, 11 female; mean age, 61+/-11 years) with suspected coronary artery disease were randomized to 2 groups to receive 100 mL of either iopromide 370 (group 1: Ultravist 370, 370 mg iodine/mL; Schering AG, Berlin, Germany) or iomeprol 400 (group 2: Iomeron 400, 400 mg iodine/mL; Bracco Imaging SpA, Milan, Italy). Both CM were administered at a rate of 4 mL/s. All patients underwent 16-MSCT coronary angiography (Sensation 16; Siemens, Germany) with collimation 16 x 0.75 mm and rotation time 375 ms. The attenuation in Hounsfield units (HU) achieved after each CM was determined at regions of interest (ROIs) placed at the origin of coronary arteries and on the ascending aorta, descending aorta, and pulmonary artery. Differences in mean attenuation in the coronary arteries and on the ascending aorta, descending aorta, and pulmonary artery were evaluated using Student t test. RESULTS: The mean attenuation achieved at each anatomic site was consistently greater after iomeprol 400 than after iopromide 370. At the origin of coronary arteries, the mean attenuation after iomeprol 400 (340+/-53 HU) was greater (P<0.05) than that after iopromide 370 (313+/- 42 HU). Similar findings were noted for the mean attenuation in the ascending aorta, descending aorta, and pulmonary artery. CONCLUSION: The intravenous administration of iomeprol 400 provides higher attenuation of the coronary arteries and of the great arteries of the thorax as compared with iopromide 370 using the same injection parameters.     

Non-ionic contrast media: a comparison of iodine delivery rates during manual injection angiography

Iodine delivery rates (IDR) of five commonly used non-ionic contrast media were determined at room temperature (24 degrees C) and body temperature (37 degrees C). Contrast media of strength 300 mgI/ml were also evaluated at 50% dilution (150 mgI/ml) with N-saline. Iodine delivery differed significantly (p less than 0.005) between samples at room temperature: Omnipaque 350 (1163 mg/s) less than Niopam 370 (1311 mg/s) less than Omnipaque 300 (1422 mg/s) less than Niopam 300 (1635 mg/s) and Ultravist 300 (1636 mg/s). Niopam 300 and Ultravist 300 delivered 41% more iodine per second than Omnipaque 350 at room temperature. Similar differences were identified at body temperature, while delivery of individual media was on average 23.5% greater than at room temperature. No significant difference between iodine delivery rates of diluted media at room temperature or body temperature was identified. The results demonstrate that iodine delivery and hence vascular opacification are better achieved during hand-injection arteriography by using relatively low viscosity media such as Niopam 300 or Ultravist 300. In digital subtraction arteriography all 300 strength contrast media diluted to 150 strength are equally effective.     

Which Iodine concentration in chest CT? – A prospective study in 300 patients

In computed tomography(CT) several contrast media with different iodine concentrations are available. The aim of this study is to prospectively compare contrast media with iodine concentrations of 300, 370 and 400 mg iodine/ml for chest- CT. 300 consecutive patients were prospectively enrolled, under a waiver of the local ethics committee. The first (second, third) 100 patients, received contrast medium with 300(370, 400)mg iodine/ml. Injection protocols were adapted for an identical iodine delivery rate(1.3 mg/s) and total iodine load(33 g) for all three groups. Standardized MDCT of the chest (16 × 0.75 mm, 120 kVp, 100 mAseff.) was performed. Intravascular attenuation values were measured in the pulmonary trunk and the ascending aorta; subjective image quality was rated on a 3-point-scale. Discomfort during and after injection was evaluated. There were no statistically significant differences in contrast enhancement comparing the three contrast media at the pulmonary trunk(p = 0.3198) and at the ascending aorta(p = 0.0840). Image quality(p = 0.0176) and discomfort during injection(p = 0.7034) were comparable for all groups. General discomfort after injection of contrast media with 300 mg iodine/ml was statistically significant higher compared to 370 mg iodine/ml(p = 0.00019). Given identical iodine delivery rates of 1.3 g/s and iodine loads of 33 g, contrast media with concentrations of 300, 370 and 400 mg iodine/ml do not result in different intravascular enhancement in chest-CT.     

Intrathyroidal iodine concentration after application of non-ionic contrast media with and without prophylactic application of perchlorate

AIM: This study was designed to show the effect of a nonionic contrast medium (Iomeprol-300; CM) on the intrathyroidal iodine concentration with and without a concomitant medication with perchlorate (1380 mg/d) to block the thyroidal iodine uptake. VOLUNTEERS AND METHODS: Twelve volunteers recieved 100 ml Iomeprol-300 intravenously and the perchlorate prophylaxis mentioned above. Another 12 volunteers got 100 ml Iomeprol-300 only. By means of X-ray-fluorescence-analysis the intrathyroidal iodine concentration was determined in advance as well as 0.2, 1, 3, 5, 7, 24, 48, 72, and 96 hours after the application of the CM. RESULTS, CONCLUSION: The intrathyroidal iodine concentration did not change in the group of volunteers on perchlorate medication. Without perchlorate the intrathyroidal iodine concentration decreased after the application of the CM when it was initially high (722 +/- 66 microg/ml before, 670 +/- 65 microg/ml after CM; p = 0.046) and increased in case of a low initial concentration (327 +/- 40 microg/ml before, 381 +/- 25 microg/ml after CM; p = 0.046). The effect is significant but its magnitude is too small to be harmful for a patient with a healthy thyroid. The oral application of 1.4 g/d perchlorate inhibits the thyroidal iodine uptake and the intrathyroidal iodine concentration is unaffected by the application of a CM.     

Impact of Different Vein Catheter Sizes for Mechanical Power Injection in CT: In Vitro Evaluation with Use of a Circulation Phantom

The purpose of this study was to evaluate the influence of different peripheral vein catheter sizes on the injection pressure, flow rate, injection duration, and intravascular contrast enhancement. A flow phantom with a low-pressure venous compartment and a high-pressure arterial compartment simulating physiological circulation parameters was used. High-iodine-concentration contrast medium (370 mg iodine/ml; Ultravist 370) was administered in the venous compartment through peripheral vein catheters of different sizes (14, 16, 18, 20, 22, and 24 G) using a double-head power injector with a pressure limit of 325 psi. The flow rate was set to 5 ml/s, with a total iodine load of 36 g for all protocols. Serial CT scans at the level of the pulmonary artery and the ascending and the descending aorta replica were obtained. The true injection flow rate, injection pressure, injection duration, true contrast material volume, and pressure in the phantom during and after injection were continuously monitored. Time enhancement curves were computed and both pulmonary and aortic peak time and peak enhancement were determined. Using peripheral vein catheters with sizes of 14–20 G, flow rates of approximately 5 ml/s were obtained. During injection through a 22-G catheter the pressure limit was reached and the flow rate was decreased, with a consecutive decreased pulmonary and aortic contrast enhancement compared to the 14- to 20-G catheters. Injection through a 24-G peripheral vein catheter was not possible because of disconnection of the canula due to the high flow rate and pressure. In summary, intravenous catheters with sizes of 14–20 G are suitable for CT angiography using an injection protocol with a high flow rate and a high-iodine-concentration contrast medium.     

Contrast enhancement in multidetector-row computed tomography (MDCT) of the abdomen: intraindividual comparison of contrast media containing 300 mg versus 370 mg iodine per ml

The purpose of this study was to intraindividually evaluate the difference in intraluminal vessel and parenchyma contrast enhancement of two different iodine concentrations in multidetector-row computed tomography (MDCT) of the abdomen. Eighty-three patients underwent baseline and follow-up MDCT-scanning (Somatom Sensation 16; Siemens, Forchheim, Germany) of the abdomen using contrast media containing 370 mg iodine/ml (protocol A; Ultravist 370, Bayer Schering Pharma, Berlin, Germany) and 300 mg iodine/ml (protocol B; Ultravist 300). The total iodine load (37 g iodine) and the iodine delivery rate (1.29 g iodine/s) were identical for both protocols. Contrast enhancement in the portal venous phase was measured in the abdominal aorta, inferior vena cava, portal vein, liver, spleen, pancreas and kidney. Mean attenuation values were compared using paired t-test. Intraindividual comparison revealed no statistically significant differences of the mean attenuation values between protocols A and B for all anatomic sites: abdominal aorta, inferior vena cava, portal vein, liver, spleen, pancreas and kidney (all P > 0.05). Given an injection protocol with constant total iodine load and constant iodine delivery rate, the iodine concentration of contrast media does not significantly influence abdominal contrast enhancement in the portal venous phase.     

A prospective study comparing different iodine concentrations for triphasic multidetector row CT of the upper abdomen

OBJECTIVES: To investigate the effect of different iodine concentrations at either constant injection or iodine administration rates but constant total iodine load on contrast enhancement of liver, pancreas and spleen by multidetector row CT. MATERIALS AND METHODS: One hundred and twenty consecutive patients (70+/-6 years) underwent triphasic liver CT at a four-channel multidetector-row CT using the non-ionic contrast medium iopromide. Patients were divided into six equal groups-I: 150 ml, 240 mg/ml at 4 ml/s; II: 120 ml, 300 mg/ml at 4 ml/s; III: 97.3 ml, 370 mg/ml at 4 ml/s; IV: 150 ml, 240 mg/ml at 5 ml/s; V: 120 ml, 300 mg/ml, 60 ml at 6 ml/s, 60 ml at 3 ml/s; VI: 97.3 ml, 370 mg/ml at 3.3 ml/s. ROIs were measured in the liver, the pancreas, and the spleen in unenhanced, arterial, portal venous, and equilibrium phase. RESULTS: At a constant injection rate of 4 ml/s, pancreatic enhancement over baseline only in the arterial phase was significantly higher at 370 mg/ml (58+/-15 HU versus 59+/-18 HU versus 74+/-20 HU for groups I-III, respectively (p<0.02)). Comparison of different iodine concentrations at constant iodine administration rate (groups II, IV and VI) and of all six protocols revealed no significant differences at either phase. CONCLUSIONS: At a constant iodine load and constant injection rates, the high-iodinated contrast agent iopromide at 370 mg/ml improves pancreatic enhancement in the arterial phase. At constant iodine load and constant iodine administration rates, there is no significant effect of different iodine concentrations.     

Intravenous contrast material administration at high-pitch dual-source CT pulmonary angiography: test bolus versus bolus-tracking technique

Purpose

To compare test bolus and bolus tracking for the determination of scan delay of high-pitch dual-source CT pulmonary angiography in patients with suspected pulmonary embolism using 50 ml of contrast material.

Materials and methods

Data of 80 consecutive patients referred for CT pulmonary angiography were evaluated. All scans were performed on a 128-channel dual-source CT scanner with a high-pitch protocol (pitch 3.0, 100 kV, 180 mA s). Contrast enhancement was achieved by injecting 50 ml of iomeprol followed by a saline chaser of 50 ml injected at a rate of 4 ml/s. The scan delay was determined using either the test bolus (n = 40) or bolus tracking (n = 40) technique. Test bolus required another 15 ml CM to determine time to peak enhancement of the contrast bolus within the pulmonary trunk. Attenuation profiles in the pulmonary trunk and on segmental level as well as in the ascending aorta were measured to evaluate the timing techniques. Additionally, overall image quality was evaluated.

Results

In all patients an adequate and homogeneous contrast enhancement of more than 250 HU was achieved in the pulmonary arteries. No statistically significant difference between test bolus and bolus tracking was found regarding attenuation of the pulmonary arteries or overall image quality. However, using bolus tracking 15 ml CM less was injected.

Conclusion

A homogeneous opacification of the pulmonary arteries and sufficient image quality can be achieved with both the bolus tracking and test bolus techniques with significant lower contrast doses compared to conventional contrast material injection protocols.     

正常成人主肺动脉的HRCT测量及其意义

目的：探讨通过正常成人主肺动脉的ＨＲＣＴ测量诊断肺动脉高压与否的可能性。方法：连续测量２００例正常成人主肺动脉直径（外径）并计算其与同一层面降主动脉直径（外径）的比值,另外采用相同方法测量１１例６０～７８岁一组已经ＣＴ与彩色Ｄｏｐｐｌｅｒ证实的ＣＯＰＤ患者主肺动脉直径及与降主动脉直径的比值并与正常组比较。结果：正常成人不同年龄,不同性别主肺动脉直径不同并有随年龄增长而增大的趋势（Ｐ＜０．０５）,但其比值与年龄有关（Ｐ＜０．０５）与性别无关（Ｐ＞０．０５）,其比值与ＣＯＰＤ患者的比值比较存在显著差异（Ｐ＜０．０１）。结论：正常成人不同年龄组主肺动脉与降主动脉的比值可作为判断肺动脉高压与否的简单、敏感的指标     

Analysis of time-density curves of contrast media for improvement of chest dynamic incremental CT.

PURPOSE: The goal of this work was to analyze time-density curves (TDCs) of contrast media (CM) in the mediastinal vasculature to optimize chest dynamic incremental CT. METHOD: Forty-three patients were injected with nonionic CM into the forearm veins with injection rates (ml/s), durations (s), and total amounts (ml) of 2.0, 20, and 40 (protocol 1); 4.0, 20, and 80 (protocol 2); and 2.0, 40, and 80 (protocol 3). TDCs were obtained for the pulmonary trunk (PA) and ascending (AA) and descending (DA) aorta from dynamic scans. Areas under the curves (AUCs) of TDCs for imaginary 30 s scans were evaluated. RESULTS: AUC peaks were obtained after 10, 17, and 19 s (PA, AA and DA; protocol 1; 9, 16, and 18 s (protocol 2); and 18, 25, and 28 s (protocol 3) delay time. CONCLUSION: Better chest dynamic incremental CT would be expected with scan midpoints a little after the end of injection of CM.     

Contrast bolus optimization for cardiac 16-slice computed tomography: comparison of contrast medium formulations containing 300 and 400 milligrams of iodine per milliliter

OBJECTIVES: The aims of our study were to compare contrast injection protocols with contrast media containing 300 and 400 mg iodine per milliliter for optimal contrast enhancement in cardiac multidector row computed tomography (CT) and to evaluate the correlation of test bolus curve parameters with the final contrast density of the main bolus. MATERIALS AND METHODS: Sixty patients with known or suspected coronary artery disease were included in a prospective double-blind study. Patients were randomized to 2 groups. Group 1 received 83 mL of a contrast medium (CM) containing 300 mg of iodine (Iomeron 300, Bracco Imaging SpA, Milan, Italy) at a flow rate of 3.3 mL/s, whereas group 2 received 63 mL of the same agent containing 400 mg of iodine (Iomeron 400) at a flow rate of 2.5 mL/s. The test bolus volumes were 20 mL and 15 mL, respectively. Imaging was performed using a 16-slice CT system (16DCT; Somatom Sensation 16, Siemens Medical Solutions, Forchheim, Germany). Contrast densities (Hounsfield Units [HU]) were determined in the cardiac chambers and in the main coronary arteries. The peak density and area under the curve of the test bolus were calculated for each patient. RESULTS: The mean contrast densities of the coronary arteries were 259.1 +/- 46.7 HU for group 1 and 251.6 +/- 51.0 HU, for group 2. No noteworthy differences between groups were noted for density measurements in the cardiac chambers or for the ratio of right-to-left ventricle density. Whereas a positive correlation was noted for both groups between the area under the curve of the test bolus and the mean density of the main bolus, a positive correlation between peak density of the test bolus and mean density of the main bolus was noted only for group 1. CONCLUSION: Equivalent homogenous enhancement of the ventricular cavities and coronary arteries to that obtained using a CM with standard iodine concentration (Iomeron 300) can be achieved with lower overall volumes of administered CM and reduced injection flow rates when a CM with high iodine concentration (Iomeron 400) is used.     

CT of the abdomen: Degree and quality of enhancement obtained with two concentrations of the same iodinated contrast medium with fixed iodine delivery rate and total iodine load

Objectives

to compare vascular and parenchymal enhancement in abdominal computed tomography (CT) using two iodine concentrations (370 vs 300 mg I/mL) of the same contrast medium (CM) molecule (iopromide), using fixed iodine delivery rate (IDR, 1.2 g I/s) and total iodine load (630 mg I/kg).

Methods

144 patients were randomized into two groups: group A receiving iopromide 370 and group B receiving iopromide 300. Attenuation values (AV) were measured in correspondence to key anatomical structures on different phases and compared between groups with parametrical tests. Qualitative analysis was also performed. Peak injection pressure and local discomfort at the site of injection (pain and warmth) were registered.

Results

mean AV of abdominal aorta in late arterial phase were 300.32 ± 59.76 for group A and 298.2 ± 59.14 for group B (p = 0.8); mean AV of portal vein in portal phase were 190.5 ± 29.92 for group A and 192.91 ± 24.12 for group B (p = 0.6). Mean AV of liver parenchyma in portal phase were 124.73 ± 18.22 for group A and 125.11 ± 15.7 for group B (p = 0.9); mean AV of liver at equilibrium were 85.11 ± 7.75 for group A and 85.41 ± 8.09 for group B (p = 0.8). Qualitative analysis did not show significant differences between groups (p > 0.05). Median peak injection pressure was lower in group B (93 psi, 76–172) than in group A (115 psi, 88–288, p < 0.0001), while discomfort at injection site was not significantly different (p > 0.05).

Conclusions

with fixed IDR and total iodine load, comparable quantitative and qualitative enhancement can be achieved with different concentrations of the same CM. Peak injection pressure increases using CM with higher iodine concentration.     

Evaluation of renal transplant donors with 16-section multidetector CT angiography: comparison of contrast media with low and high iodine concentrations

PURPOSE: To compare the degree of contrast enhancement, image quality, and accuracy of renal computed tomographic (CT) angiography performed with a 16-detector row CT unit and equal iodine doses of low- and high-iodine-concentration contrast medium in the evaluation of renal transplant donors. MATERIALS AND METHODS: Eighty donors scheduled to undergo renal CT angiography with 16-detector row CT were administered nonionic contrast media with two iodine concentrations. The first group (group A, n=40) received a contrast medium with 300 mg of iodine per milliliter, and the second group (group B, n=40) received a contrast medium with 370 mg of iodine per milliliter. An equal iodine dose of 550 mg per kilogram body weight was given to both groups. Contrast enhancement was quantified by measuring attenuation in the abdominal aorta and in both renal arteries. Subjective assessment of contrast enhancement, quality of reformatted images, and visualization of branch order of renal arteries were rated with a 5-point scale. The number of renal arteries and veins seen at CT was correlated with the results at surgery. RESULTS: The mean enhancement values in group B were significantly greater (P<.001) than those in group A. The mean HU (+/-standard deviation) in groups A and B were 298+/-76 and 344+/-75, respectively, in the aorta, 284+/-74 and 331+/-71 in the right renal artery, and 285+/-72 and 329+/-73 in the left renal artery. The mean enhancement, image quality, and branch orders visualized were rated better in group B than in group A (P<.01). The accuracies for correctly identifying renal arteries and veins, respectively, were 91% and 95% for group A and 96% and 96% for group B. CONCLUSION: Renal donor CT angiography with a contrast medium of 370 mg of iodine per milliliter provides greater enhancement and image quality compared with a contrast medium of 300 mg of iodine per milliliter. The diagnostic accuracies were similar.     

Triphasic contrast injection improves evaluation of dual energy lung perfusion in pulmonary CT angiography

Purpose

Lung perfusion analysis at dual energy CT (DECT) is sensitive to beam hardening artifacts from dense contrast material (CM). We compared two scan and four CM injection protocols in terms of severity of artifacts and attenuation levels in the thoracic vessels.

Methods and materials

Data of 120 patients who had undergone dual source dual energy CT pulmonary angiography for suspected acute pulmonary embolism were evaluated. Group 1 (n = 30) was scanned in craniocaudal direction using 64 × 0.6 mm collimation; groups 2–4 (n = 30 each) were scanned in caudocranial direction using 14 × 1.2 mm collimation. In groups 1–3 biphasic injection protocols with different amounts of CM and NaCl were investigated. In group 4 a split-bolus protocol with an initial CM bolus of 50 ml followed by 30 ml of a 70%:30% NaCl/CM mixture and a 50 ml NaCl chaser bolus was used. CT density values in the subclavian vein (SV), superior vena cava (SVC), pulmonary artery tree (PA), and the descending aorta (DA) were measured. Artifacts arising from the SV and SVC on DE pulmonary iodine distribution map were rated on a scale from 1 to 5 (1 = fully diagnostic; 5 = non-diagnostic) by two blinded readers.

Results

In protocol 4 mean attenuation in the SV (645 ± 158 HU) and SVC (389 ± 114 HU) were significantly lower compared to groups 1–3 (p < 0.002). Artifacts in group 4 (1.1 ± 0.4 and 1.5 ± 0.7 for the SV and SVC, respectively) were rated significantly less severe compared to group 1 (3.2 ± 1.0 and 3.0 ± 1.1), 2 (2.6 ± 1.1 and 2.3 ± 1.0) and 3 (1.9 ± 0.9 and 1.9 ± 0.7) (p < 0.01 for all), whereas no significant difference was found between groups 1 and 2 for the subclavian vein (p = 0.07). Attenuation in the PA was also significantly lower in group 4 (282 ± 116 HU) compared to group 1 (397 ± 137 HU), group 2 (376 ± 115 HU) and group 3 (311 ± 104 HU), but still on a diagnostic level.

Conclusion

Split-bolus injection provides sufficient attenuation for pulmonary DECT angiography while beam hardening artifacts arising from high density contrast material in the thoracic vessels can be reduced significantly.     

Reduction of contrast material dose and artifacts by a saline flush using a double power injector in helical CT of the thorax

OBJECTIVE: Our objective was to evaluate a combined method of contrast material bolus followed by saline solution flush for thoracic helical CT and statistical comparison with a uniphasic injection protocol. MATERIALS AND METHODS: Fifty patients underwent helical CT of the thorax using 60 ml of contrast material (370 mg I/ml) followed by flushing with 30 ml of physiologic saline solution. These 50 patients had been examined before using our previous protocol, 75 ml of the same contrast material without a subsequent saline solution. Mean attenuation values for both protocols were measured in the superior vena cava, the pulmonary trunk, and the ascending aorta. Image artifacts and mediastinal and hilar depiction were graded and compared. RESULTS: Mean attenuation values in the superior vena cava were considerably higher in the regimen without saline solution flush (459 H versus 352 H) and in the pulmonary trunk and the ascending aorta were almost identical for both protocols. Injection of saline solution diminished surrounding artifacts (p = 0.001). Grading results for the evaluation of mediastinal and hilar structures were not significantly different in the two protocols (p = 0.564). CONCLUSION: Injection of contrast material followed by a saline solution bolus using a double power injector when performing thoracic helical CT allows a 20% reduction of contrast material volume to 60 ml with a similar degree of enhancement. In addition, perivenous artifacts in the superior vena cava are significantly reduced.     

Low voltage CTPA for patients with suspected pulmonary embolism

Objective

To test a low dose, low voltage protocol for the diagnosis of pulmonary embolism.

Materials and methods

50 Patients with clinically suspected pulmonary embolism underwent CTPA with 80 kVp and 295 mAs (test group) on a 64-row MDCT scanner. These patients were compared to a similar group of 50 patients scanned on the same scanner with the 120 kVp protocol with automatic tube current modulation (control group). All patients received 100–110 ml of a 370 mgI/ml solution at 4.5 cm³/s. Scans were compared for quantitative imaging parameters (attenuation and standard deviation in the main, right and left pulmonary arteries, in a lobar and segmental pulmonary artery and in the aorta) and for dose parameters (CTDI and DLP), using an unpaired t-test. Phantom measurements were also performed for image quality parameters and radiation dose.

Results

Mean attenuation was significantly higher in the test group than in the control group in the main pulmonary trunk, in the right pulmonary artery, in the left pulmonary artery, in a lobar and segmental pulmonary artery and in the ascending aorta (all: p ≤ 0.0001). Noise was significantly higher in the test group than in the control group, but contrast to noise ratio was not significantly different between the two protocols. Radiation dose was significantly lower in the test group than in the control group, as measured by CTDI, DLP and effective dose to organs (all: p < 0.0001).

Conclusions

The use of 80 kVp for pulmonary CTA significantly reduces patient radiation exposure, and significantly increases contrast medium attenuation in the pulmonary arteries, with no effect on the diagnostic quality of the exams.     

Effect of iodine concentration of contrast media on contrast enhancement in multislice CT of the pancreas

The purpose of this study was to determine the influence of two different iodine concentrations of the non-ionic contrast agent, Iomeprol, on contrast enhancement in multislice CT (MSCT) of the pancreas. To achieve this MSCT of the pancreas was performed in 50 patients (mean age 57+/-14 years) with suspected or known pancreatic tumours. The patients were randomly assigned to group A (n=25 patients) or group B (n=25 patients). There were no statistically significant differences in age, height or weight between the patients of the two groups. The contrast agent, Iomeprol, was injected with iodine concentrations of 300 mg ml(-1) in group A (130 ml, injection rate 5 ml s(-1)) and 400 mg ml(-1) in group B (98 ml, injection rate 5 ml s(-1)). Arterial and portal venous phase contrast enhancement (HU) of the vessels, organs, and pancreatic masses were measured and a qualitative image assessment was performed by two independent readers. In the arterial phase, Iomeprol 400 led to a significantly greater enhancement in the aorta, superior mesenteric artery, coeliac trunk, pancreas, pancreatic carcinomas, kidneys, spleen and wall of the small intestine than Iomeprol 300. Portal venous phase enhancement was significantly greater in the pancreas, pancreatic carcinomas, wall of the small intestine and portal vein with Iomeprol 400. The two independent readers considered Iomeprol 400 superior over Iomeprol 300 concerning technical quality, contribution of the contrast agent to the diagnostic value, and evaluability of vessels in the arterial phase. No differences were found for tumour delineation and evaluability of infiltration of organs adjacent to the pancreas between the two iodine concentrations. In conclusion the higher iodine concentration leads to a higher arterial phase contrast enhancement of large and small arteries in MSCT of the pancreas and therefore improves the evaluability of vessels in the arterial phase.     

Right-to-left shunts with right ventricular hypertrophy: Pathologic aspects

When a right-to-left shunt occurs on the basis of congenital cardiac disease, a major dividing point in differential diagnosis is whether or not right ventricular hypertrophy is present. When right ventricular hypertrophy is present, the shunt may occur either at the ventricular or atrial level. When the shunt occurs at the ventricular level, cases may be subdivided according to the vascular connections with the right ventricle into the following groups: (1) connection of the ascending aorta and of the pulmonary trunk with the right ventricle, (2) connection of the ascending aorta alone with the right ventricle, and (3) connection of the pulmonary trunk and of the descending aorta (through a PDA) with the right ventricle.

When a transatrial right-to-left shunt occurs, it is on the basis either of

1. (1) right ventricular hypertrophy incident to pulmonary stenosis or atresia or

2. (2) total anomalous connection of the pulmonary veins.

     

低管电压联合低碘对比剂在CTPA中的可行性研究

目的 探讨低管电压联合低碘对比剂在CT肺动脉成像(CTPA)中的可行性。方法 连续收集行CTPA的受检者100例,采用随机数字表法分为实验组和对照组。实验组：男27人,女23人,年龄31～77岁,平均(55.1±8.4)岁,管电压80kV,碘海醇30ml(含碘量300mg/ml);对照组：男24人,女26人,年龄30～72岁,平均(54.3±7.1)岁,管电压100kV,碘普罗胺30ml(含碘量370mg/ml)。两组间肺动脉强化CT值、噪声值、信噪比(SNR)、有效剂量(ED)、碘摄入量的比较采用t检验,图像质量评分的比较采用Mann-whitney U检验。结果 两组图像质量评分差异无统计学意义(Z=-0.821,P>0.05)。实验组肺动脉强化CT值、噪声值[(336.6±41.0)HU、(15.0±2.5)HU]明显高于对照组[(301.4±36.2)HU、(10.4±1.5)HU],SNR(23.6±5.8)明显低于对照组(29.1±6.4),差异均有统计学意义(t=1.518、0.660、1.061,P<0.05)。实验组、对照组ED分别为(1.8±0.2)mSv、(3.9±0.9)mSv,差异有统计学意义(t=0.461,P<0.05)。实验组碘摄入量(9.0g)较对照组(11.1g)降低了约18.9%。结论 低管电压联合低对比剂碘摄入量在CTPA中是可行的,能明显降低受检者的辐射剂量和碘摄入量。     

Optimization of contrast agent volume for helical CT in the diagnostic assessment of patients with severe and multiple injuries.

PURPOSE: The aim of this study was to determine the optimal amount of contrast agent for helical CT of the trunk during primary radiologic evaluation of polytraumatized patients. METHOD: Eighty-three patients with severe and multiple injuries (mean age 36.2 years) underwent standardized helical CT examination with administration of a single contrast agent bolus of iohexol (Accupaque 300) at volumes of 120, 150, and 180 ml. Image quality was estimated by two blinded radiologists using a visual analogue scale. Analysis further included density measurements in regions of interest (ROIs) placed in the ascending, descending, and abdominal aorta as well as in the liver and spleen. RESULTS: The qualitative rating of the contrast agent effect after administration of 150 and 180 ml was significantly better compared with 120 ml [odds ratio (OR) 12.05, 95% confidence interval (CI) 3.50-41.52 and OR 12.14, 95% CI 3.36-43.85, respectively]. A dose increase from 120 to 150 ml resulted in a significantly better enhancement of the abdominal aorta (p = 0.006). The highest dose of 180 ml was not associated with a diagnostic gain in the other ROIs. CONCLUSION: We recommend administration of 150 ml of iohexol as the optimal amount of contrast material for single phase bolus administration in emergency helical CT examination of the chest and abdomen.