Coronavirus Vaccination: Spike Antibody Levels in Health Workers after Six Months-A Cross-Sectional Study.

Healthcare workers bear a high risk of infection during epidemics and pandemics such as the current SARS-CoV-2 pandemic. Various new vaccines have been approved. We investigated the influence of the time elapsed since vaccination, as well as of vaccination schema, on health workers' spike antibody levels following their second vaccination. Blood samples were obtained from employees working at a German hospital between August 2021 and December 2021 on average half a year (range 130-280 days) after their second vaccination. Levels of SARS-CoV-2-IgG antibodies (spike and nucleocapsid protein) were qualitatively detected via chemiluminescent immunoassays (CLIAs). A previous infection with SARS-CoV-2 was an exclusion criterion. In total, 545 persons were included in this cross-sectional study. Most participants (97.8%) showed elevated anti-spike concentrations. Anti-spike levels differed significantly among vaccination schemas. Repeated vector vaccinations resulted in lower protective antibody levels. Higher age levels, immunosuppression and a longer time period since the second vaccination resulted in lower anti-spike levels. Women's antibody levels were higher, but not significantly. Since anti-spike levels drop after vaccination, further boosters are required to increase immunoreactivity. If two vector vaccines have been administered, it is possible that an mRNA booster might increase the anti-spike level.

COVID-19 infections in staff of an emergency care hospital after the first wave of the pandemic in Germany.

Background: Hospital staff have an increased risk of SARS-CoV-2 infection. It is thus necessary to monitor the situation because infected staff may in turn infect patients and their family members. Following the first wave of infection in the summer of 2020, the Rhine-Maas Hospital (RMK) provided all staff the opportunity to be tested for SARS-COV-2 via antibody testing. Methods: The tests were carried out from 19.6.2020 to 17.7.2020. The IgG antibody test qualitatively tested for SARS-CoV-2 antibodies via enzyme-linked immunosorbent assay (ELISA). An IgG titre of 0.8 IU/mL or more was considered positive. All staff who tested positive for SARS-CoV-2 by PCR testing after February 2020 were also included in the study. Occupational and non-occupational risk factors for infection were determined. Staff in the intensive care ward, the emergency depart-ment, or a SARS-CoV-2 ward ("corona ward") were predefined as having increased exposure. Odds ratios (OR) were calculated using logistical regression for occupational and private infection risk. Results: 903 staff members (58.9%) with complete data took part in the cross-sectional study. 52 staff members (5.8%) had a positive PCR test result in their medical history or tested positive in the IgG test. Around half of the infections (55%) were only detected by serological testing during the study. Staff with tasks classified as at-risk had an OR of 1.9 (95% CI 1.04-3.5) for infection. Risk factors also included private contacts to people infected with SARS-CoV-2 and holidays in risk areas. At the time of data collection, 11.5% of those with the disease reported that they had not yet fully recovered from COVID-19. Discussion: Following the first COVID-19 wave, 5.3% of staff at the RMK were infected. An increase in occupational infection risk was found even after controlling for non-occupational infection risks. This should be taken into account with regard to the recognition of COVID-19 as an occupational disease. Methods to improve protection against nosocomial transmissions should be considered.

[Does SARS-CoV-2 cause lung inflammation even in mild clinical courses? : A multicenter report from outpatient care]. / Verursacht SARS-CoV-2 auch bei milden klinischen Verläufen eine Lungenentzündung? : Ein Multicenterbericht aus der ambulanten Versorgung.

OBJECTIVE: In spring 2020 imaging findings of the lungs were found in several radiological practices and in outpatient clinic patients, which indicated acute or previous viral pneumonia. It was striking that many of the patients affected had only mild symptoms. In this case study it was investigated to what extent SARS-CoV­2 can cause lung involvement even with minor symptoms. MATERIAL AND METHODS: In this study five outpatient radiological centers and two inpatient hospitals in North Rhine-Westphalia and Baden-Württemberg in Germany were involved. The retrospective analysis included outpatients with radiologically detected viral pneumonia, who were examined in March or April 2020. The clinical symptoms were divided into severity levels 1-5 using a simplified clinical score. The lung images were evaluated with respect to features specific for COVID-19 . The presence of a SARS-CoV­2 infection was verified using PCR, antibody testing and/or typical computed tomography (CT) morphology. RESULTS: A total of 50 patients were included, all of whom had radiological signs of viral pneumonia. The majority had no or only few non-specific symptoms (26/50). This was followed by mild symptoms of a flu-like infection (17/50). Severe forms were rare in outpatients (7/50). Detection of COVID-19 was successful in 30/50 cases using PCR and in 4/50 cases using an antibody test. In 16/50 cases the diagnosis was based on typical CT criteria and on the typical COVID patient history. CONCLUSION: A SARS-CoV­2 infection leads to lung involvement more often than previously assumed, namely not only in severely ill hospitalized patients but also in cases with only mild or even non-specific symptoms.

Endovascular retrieval of a dislocated coil in the peroneal artery with a stent retriever.

We present a patient who underwent successful removal of a fully detached platinum coil from the peroneal artery using a Solitaire™ stent retriever (Covidien, Irvine, CA) that is usually used in endovascular stroke treatment.

Serum levels of C-peptide are associated with coronary artery calcification in patients with rheumatoid arthritis.

C-peptide has pro-atherogenic effects in animal models, and elevated C-peptide levels are associated with cardiovascular and all-cause mortality in patients undergoing coronary angiography. This cross-sectional study investigated the association between C-peptide serum levels and coronary artery calcification (CAC) in patients with rheumatoid arthritis (RA), a high-risk group for cardiovascular events. Fifty-four patients with RA were recruited from an arthritis outpatient department at the University Hospital in Aachen, Germany. CAC was measured by multi-slice CT scan, and blood samples were drawn from all patients for the analysis of C-peptide and other cardiovascular biomarkers. Mean serum levels of C-peptide (1.187 ± 0.771 vs 0.745 ± 0.481 nmol/L, p = 0.02), YKL-40, LDL cholesterol, and triglycerides were significantly higher in patients with CAC (n = 32, 59 %) compared to those without CAC (n = 22, 41 %). Univariate analysis revealed a significant association of C-peptide [OR 4.7, 95 % CI (1.1, 20.2)], YKL-40, triglycerides, hypertension, smoking, age, and male sex with the presence of CAC. After adjustment for body mass index, cholesterol, diabetes, adiponectin, calcium, and phosphate, C-peptide was still significantly associated with CAC in a multivariate logistic regression model. In conclusion, C-peptide serum levels are independently associated with the presence of CAC in patients with RA. These data suggest a potential role of C-peptide in cardiovascular disease in patients with RA.

Vascular anatomy of the small intestine-a comparative anatomic study on humans and pigs.

BACKGROUND: Porcine models are well established for studying intestinal anastomotic healing. In this study, we aimed to clarify the anatomic differences between human and porcine small intestines. Additionally, we investigated the influences of longitudinal and circular sutures on human small intestine perfusion. METHODS: Intestines were obtained from human cadavers (n = 8; small intestine, n = 51) and from pigs (n = 10; small intestine, n = 60). Vascularization was visualized with mennige gelatin perfusion and high-resolution mammography. Endothelial cell density was analyzed with immunohistochemistry and factor VIII antibodies. We also investigated the influence of suture techniques (circular anastomoses, n = 19; longitudinal sutures, n = 15) on vascular perfusion. RESULTS: Only human samples showed branching of mesenteric vessels. Compared to the pig, human vessels showed closer connections at the entrance to the bowel wall (p = 0.045) and higher numbers of intramural anastomoses (p < 0.001). Porcine main vessels formed in multifilament-like vessel bundles and displayed few intramural vessel anastomoses. Circular anastomoses induced a circular perfusion defect at the bowel wall; longitudinal anastomoses induced significantly smaller perfusion defects (p < 0.001). Both species showed higher vascular density in the jejunum than in the ileum (p < 0.001). Human samples showed similar vascular density within the jejunum (p = 0.583) and higher density in the ileum (p < 0.001) compared to pig samples. CONCLUSION: The results showed significant differences between human and porcine intestines. The porcine model remains the standard for studies on anastomotic healing because it is currently the only viable model for studying anastomosis and wound healing. Nevertheless, scientific interpretations must consider the anatomic differences between humans and porcine intestines.

Influence of contrast media viscosity and temperature on injection pressure in computed tomographic angiography: a phantom study.

PURPOSE: Iodinated contrast media (CM) in computed tomographic angiography is characterized by its concentration and, consecutively, by its viscosity. Viscosity itself is directly influenced by temperature, which will furthermore affect injection pressure. Therefore, the purposes of this study were to systematically evaluate the viscosity of different CM at different temperatures and to assess their impact on injection pressure in a circulation phantom. MATERIALS AND METHODS: Initially, viscosity of different contrast media concentrations (240, 300, 370, and 400 mgI/mL) was measured at different temperatures (20°C-40°C) with a commercially available viscosimeter. In the next step, a circulation phantom with physical conditions was used. Contrast media were prepared at different temperatures (20°C, 30°C, 37°C) and injected through a standard 18-gauge needle. All other relevant parameters were kept constant (iodine delivery rate, 1.9 g I/s; total amount of iodine, 15 g I). Peak flow rate (in milliliter per second) and injection pressure (psi) were monitored. Differences in significance were tested using the Kruskal-Wallis test (Statistical Package for the Social Sciences). RESULTS: Viscosities for iodinated CM of 240, 300, 370, and 400 mg I/mL at 20°C were 5.1, 9.1, 21.2, and 28.8 mPa.s, respectively, whereas, at 40°C, these were substantially lower (2.8, 4.4, 8.7, and 11.2 mPa.s). In the circulation phantom, mean (SD) peak pressures for CM of 240 mg I/mL at 20°C, 30°C, and 37°C were 107 (1.5), 95 (0.6), and 92 (2.1) psi; for CM of 300 mg I/mL, 119 (1.5), 104 (0.6), and 100 (3.6) psi; for CM of 370 mg I/mL, 150 (0.6), 133 (4.4), and 120 (3.5) psi; and for CM of 400 mg I/mL, 169 (1.0), 140 (2.1), and 135 (2.9) psi, respectively, with all P values less than 0.05. CONCLUSIONS: Low concentration, low viscosity, and high temperatures of CM are beneficial in terms of injection pressure. This should also be considered for individually tailored contrast protocols in daily routine scanning.

Relationship between sclerostin and cardiovascular calcification in hemodialysis patients: a cross-sectional study.

BACKGROUND: Sclerostin is a Wnt pathway antagonist regulating osteoblast activity and bone turnover. Here, we assessed the potential association of sclerostin with the development of coronary artery (CAC) and aortic valve calcifications (AVC) in haemodialysis (HD) patients. METHODS: We conducted a cross-sectional multi-slice computed tomography (MS-CT) scanning study in 67 chronic HD patients (59.4 ± 14.8 yrs) for measurement of CAC and AVC. We tested established biomarkers as well as serum sclerostin (ELISA) regarding their association to the presence of calcification. Fifty-four adults without relevant renal disease served as controls for serum sclerostin levels. Additionally, sclerostin expression in explanted aortic valves from 15 dialysis patients was analysed ex vivo by immunohistochemistry and mRNA quantification (Qt-RT-PCR). RESULTS: CAC (Agatston score > 100) and any AVC were present in 65% and in 40% of the MS-CT patient group, respectively. Serum sclerostin levels (1.53 ± 0.81 vs 0.76 ± 0.31 ng/mL, p < 0.001) were significantly elevated in HD compared to controls and more so in HD patients with AVC versus those without AVC (1.78 ± 0.84 vs 1.35 ± 0.73 ng/mL, p = 0.02). Multivariable regression analysis for AVC revealed significant associations with higher serum sclerostin. Ex vivo analysis of uraemic calcified aortic valves (n = 10) revealed a strong sclerostin expression very close to calcified regions (no sclerostin staining in non-calcified valves). Correspondingly, we observed a highly significant upregulation of sclerostin mRNA in calcified valves compared to non-calcified control valves. CONCLUSION: We found a strong association of sclerostin with calcifying aortic heart valve disease in haemodialysis patients. Sclerostin is locally produced in aortic valve tissue adjacent to areas of calcification.

Intravascular enhancement with identical iodine delivery rate using different iodine contrast media in a circulation phantom.

PURPOSE: Both iodine delivery rate (IDR) and iodine concentration are decisive factors for vascular enhancement in computed tomographic angiography. It is unclear, however, whether the use of high-iodine concentration contrast media is beneficial to lower iodine concentrations when IDR is kept identical. This study evaluates the effect of using different iodine concentrations on intravascular attenuation in a circulation phantom while maintaining a constant IDR. MATERIALS AND METHODS: A circulation phantom with a low-pressure venous compartment and a high-pressure arterial compartment simulating physiological circulation parameters was used (heart rate, 60 beats per minute; stroke volume, 60 mL; blood pressure, 120/80 mm Hg). Maintaining a constant IDR (2.0 g/s) and a constant total iodine load (20 g), prewarmed (37°C) contrast media with differing iodine concentrations (240-400 mg/mL) were injected into the phantom using a double-headed power injector. Serial computed tomographic scans at the level of the ascending aorta (AA), the descending aorta (DA), and the left main coronary artery (LM) were obtained. Total amount of contrast volume (milliliters), iodine delivery (grams of iodine), peak flow rate (milliliter per second), and intravascular pressure (pounds per square inch) were monitored using a dedicated data acquisition program. Attenuation values in the AA, the DA, and the LM were constantly measured (Hounsfield unit [HU]). In addition, time-enhancement curves, aortic peak enhancement, and time to peak were determined. RESULTS: All contrast injection protocols resulted in similar attenuation values: the AA (516 [11] to 531 [37] HU), the DA (514 [17] to 531 [32] HU), and the LM (490 [10] to 507 [17] HU). No significant differences were found between the AA, the DA, and the LM for either peak enhancement (all P > 0.05) or mean time to peak (AA, 19.4 [0.58] to 20.1 [1.05] seconds; DA, 21.1 [1.0] to 21.4 [1.15] seconds; LM, 19.8 [0.58] to 20.1 [1.05] seconds). CONCLUSIONS: This phantom study demonstrates that constant injection parameters (IDR, overall iodine load) lead to robust enhancement patterns, regardless of the contrast material used. Higher iodine concentration itself does not lead to higher attenuation levels. These results may stimulate a shift in paradigm toward clinical usage of contrast media with lower iodine concentrations (eg, 240 mg iodine/mL) in individual tailored contrast protocols. The use of low-iodine concentration contrast media is desirable because of the lower viscosity and the resulting lower injection pressure.

Simultaneous dual-isotope SPECT/CT with (99m)Tc- and (111)In-labelled albumin microspheres in treatment planning for SIRT.

OBJECTIVES: To investigate simultaneous dual-isotope SPECT/CT with two differently radioisotope-labelled albumin-microsphere fractions for treatment planning of hepatic radioembolisation. METHODS: In addition to (99m)Technetium-labelled albumin microspheres (commercially available), we performed labelling with (111)Indium. Binding stability of (111)Indium-labelled microspheres was tested in vitro and in vivo in mice. Simultaneous dual-isotope SPECT/CT imaging was validated in an anthropomorphic torso phantom; subsequently, dual-isotope SPECT/CT was performed under in-vivo conditions in pigs (n = 3) that underwent transarterial injection of (99m)Technetium- and (111)Indium-labelled microspheres in the liver (right and left hepatic artery, respectively), in both kidneys and in the gluteal musculature. In total, n = 18 transarterial injections were performed. RESULTS: In-vitro testing and in-vivo studies in mice documented high binding stability for both (99m)Technetium-labelled and (111)Indium-labelled microsphere fractions. In phantom studies, simultaneous dual-isotope SPECT/CT enabled reliable separation of both isotopes. In pigs, the identified deposition of both isotopes could be accurately matched with intended injection targets (100 %, 18/18 intended injection sites). Furthermore, an incidental deposition of (99m)Technetium-labelled microspheres in the stomach could be correlated to the test injection into a right hepatic artery. CONCLUSION: Simultaneous dual-isotope SPECT/CT after transarterial injection with (99m)Technetium- and (111)Indium-labelled microspheres is feasible. Thus, it may offer additional, valuable information compared to single (99m)Technetium-labelled albumin examinations. KEY POINTS: • Simultaneous dual-isotope SPECT/CT with (111) In- and (99m) Tc-labelled albumin microspheres is feasible. • Differentiation of two microsphere fractions after transarterial injection is possible. • The origin of an extra-hepatic microsphere deposition can be correlated to the corresponding artery. • This technique could reduce the setup time for selective internal radiation treatment.

Endovascular broad-neck aneurysm creation in a porcine model using a vascular plug.

PURPOSE: Ruptured cerebral arterial aneurysms require prompt treatment by either surgical clipping or endovascular coiling. Training for these sophisticated endovascular procedures is essential and ideally performed in animals before their use in humans. Simulators and established animal models have shown drawbacks with respect to degree of reality, size of the animal model and aneurysm, or time and effort needed for aneurysm creation. We therefore aimed to establish a realistic and readily available aneurysm model. MATERIALS AND METHODS: Five anticoagulated domestic pigs underwent endovascular intervention through right femoral access. A total of 12 broad-neck aneurysms were created in the carotid, subclavian, and renal arteries using the Amplatzer vascular plug. RESULTS: With dedicated vessel selection, cubic, tubular, and side-branch aneurysms could be created. Three of the 12 implanted occluders, two of them implanted over a side branch of the main vessel, did not induce complete vessel occlusion. However, all aneurysms remained free of intraluminal thrombus formation and were available for embolization training during a surveillance period of 6 h. Two aneurysms underwent successful exemplary treatment: one was stent-assisted, and one was performed with conventional endovascular coil embolization. CONCLUSION: The new porcine aneurysm model proved to be a straightforward approach that offers a wide range of training and scientific applications that might help further improve endovascular coil embolization therapy in patients with cerebral aneurysms.

Development and validation of an intrinsic landmark-based gating protocol applicable for functional and molecular ultrasound imaging.

OBJECTIVES: To implement a retrospective intrinsic landmark-based (ILB) gating protocol for contrast-enhanced ultrasound (CEUS) and to compare its efficiency to non-gated, manually gated and extrinsically gated CEUS. METHODS: CEUS of the liver was performed in healthy mice (n = 5) and in NEMO knockout mice with dysplastic livers (n = 5). In healthy animals, first-pass kinetics of non-specific microbubbles was recorded. Knockout mice were analysed regarding retention of VEGFR2-specific microbubbles. For retrospective gating, a landmark which showed respiratory movement was encircled as a region of interest (ROI). During inspiration, the signal intensity within the ROI altered, which served as gating signal. To evaluate the accuracy, non-gated, extrinsically gated and ILB-gated time-intensity curves were created. For each curve, descriptive parameters were calculated and compared to the gold standard (manual frame-by-frame gating). RESULTS: No significant differences in the variation of ILB- and extrinsically gated time-intensity curves from the gold standard were observed. Non-gated data showed significantly higher variations. Also the variation of molecular ultrasound data was significantly lower for ILB-gated compared to non-gated data. CONCLUSION: ILB gating is a robust and easy method to improve data accuracy in functional and molecular ultrasound liver imaging. This technique can presumably be translated to contrast-enhanced ultrasound examinations in humans. KEY POINTS: • Quantitative analysis of the uptake of contrast agents during ultrasound is complex. • Intrinsic landmark-based gating (ILB) offers a simple implementable method for motion correction. • Results using ILB-gating are comparable to extrinsic gating using external biomonitoring devices. • Functional and molecular imaging of mobile organs will benefit from ILB gating.

Virtual elastic sphere processing enables reproducible quantification of vessel stenosis at CT and MR angiography.

PURPOSE: To develop and evaluate a user-friendly tool to enable efficient, accurate, and reproducible quantification of blood vessel stenosis in computed tomographic (CT) and magnetic resonance (MR) angiographic data sets. MATERIALS AND METHODS: All clinical experiments were approved by the institutional review board, and informed patient consent was acquired. Animal experiments were approved by the governmental review committee on animal care. A virtual elastic sphere passes through a blood vessel specified by user-provided start and end points, and the adapting diameter over the course of the vessel is recorded. The program was tested in phantoms to determine the accuracy of diameter estimation, and it was applied in micro-CT data sets of mice with induced vessel stenosis. Dual-energy CT angiography and MR angiography were performed in 16 patients with carotid artery stenosis, and reproducibility and required reader time of this automated technique were compared with manual measurements. Additionally, the effect of dual-energy CT-based discrimination between iodine- and calcium-based enhancement was investigated. Differences between carotid artery diameters of mice and between automated and manual measurement durations were assessed with a paired t test. Reproducibility of stenosis scores was evaluated with the Fisher z test. RESULTS: Phantom diameters were determined with an average error of 0.094 mm. Diameters of normal and injured carotid arteries of mice were significantly different (P < .01). For patient data, automated interreader variability was significantly (P < .01) lower than manual intra- and interreader variability, while time efficiency was improved (P < .01). CONCLUSION: The virtual elastic sphere tool is applicable to CT, dual-energy CT, and MR angiography, and it improves reproducibility and efficiency over that achieved with manual stenosis measurements.

Dual-source CT assessment of ventricular function in healthy and infarcted myocardium: an animal study.

PURPOSE: To assess global and regional ventricular function in the presence of myocardial infarction (MI) using cardiac dual-source computed tomography (DSCT) in comparison to magnetic resonance (MR) imaging. MATERIALS AND METHODS: Fourteen pigs (58.6 ± 8.9 kg) were included in this study. In seven animals acute MI was induced by temporary balloon occlusion of the left circumflex artery. Thereafter, DSCT and MR imaging were performed with standardized examination protocols. Left (LV) and right ventricular (RV) volumes, ejection fraction (EF), peak filling rate (PFR), and peak ejection rate (PER) as well as LV myocardial mass were calculated. LV wall motion was visually assessed from cine loops. Data was analyzed using Bland-Altman plots, Lin's concordance-correlation coefficient (ρ(c)) and weighted kappa statistics. RESULTS: Ventricular volumes and mass as determined by DSCT correlated well with MR imaging. Mean LV-EF was 49.4 ± 16.5% on DSCT and 50.0 ± 16.1% on MR imaging (ρ(c) = 0.9928). The corresponding mean RV-EF results were 45.9 ± 10.6% and 45.8 ± 10.6% (ρ(c) = 0.9969), respectively. Bland-Altman plots revealed no systematic errors, but PER and PFR showed a relevant scattering. Regional wall motion scores agreed in 216/224 myocardial segments (κ = 0.925). CONCLUSION: DSCT permits the reliable assessment of global and regional function in healthy and infarcted myocardium, but is not yet suited for the assessment of dynamic functional parameters like PER and PFR.

Registration of coronary venous anatomy to the site of the latest mechanical contraction.

OBJECTIVE: Cardiac resynchronization therapy (CRT) provides a therapeutic option for patients with congestive heart failure (CHF). There is evidence that the optimal pacing site (OIS) is vicinal to the region of the latest contraction (RLC). However, the RLC is not identified routinely to guide lead implantation to the coronary venous system (CVS). The aim of this study was: (i) to develop a software over-imposing CVS-anatomy on parametric images of left ventricular dyssynchrony in a 3D-format obtained from computed tomography (CT) and cardiac magnetic resonance imaging (MRI); and (ii) to apply this 3D-software for analysing the possible correlation between functional/ clinical improvement and the distance between final implantation site (FIS) and RLC. METHODS AND RESULTS: In 20 CHF-patients (11 men, 65.6 +/- 6.8 y, ejection fraction (EF): 27.5 +/- 6.1%) CRT-leads were implanted; follow-up included echocardiographic and exercise evaluation. The OIS and the FIS were noted on 3D-registrations and the distances OIS-RLC and FIS-RLC measured.The target vessel was reached in 14 cases. NYHA class and EF improved significantly with a low rate of non-responders of 3 (15%) (EF) and 4 (20%) (NYHA). Image registration was possible in all patients. Post-process 3D-analysis revealed no correlation between the distance FIS-RLC and functional or echocardiographic improvements.There was a trend towards a shorter distance FIS-RLC in patients classified as responders (EF). NYHA class improved significantly better in patients with target vessel implantation. CONCLUSIONS: Registration of CT/MRI-images enables efforts to reach the RLC by preoperative identification of corresponding veins. Larger randomized trials must define the definite therapeutic benefit.

Comparison of dual-source CT angiography and MR angiography in preoperative evaluation of intra- and extracranial vessels: a pilot study.

Besides the assessment of carotid artery stenosis, evaluation of the vascular anatomy and lesions within both the extra- and intracranial arteries is crucial for proper clinical evaluation, treatment choice and planning. The purpose of our study was to evaluate the potential of dual-source CTA and 3T-MRA. In 16 symptomatic CAS patients, contrast-enhanced DSCT and 3T-MRA examinations were performed. For DSCT a dual-energy protocol with a 64 x 0.6-mm collimation was applied. In 3T-MRA intracranial high-resolution unenhanced TOF and extracranial contrast-enhanced MRA were performed. All examinations were analyzed for relevant morphologic and pathologic features or anomalies, and a total of 624 vessel segments were scored. All examinations were of diagnostic image quality with good to excellent vessel visibility. Almost all intracranial arteries were significantly better visualized by MRA compared to CTA (five of six vessels, p < 0.05). DSCT however allowed for further morphological carotid stenosis description, especially with respect to calcification. Although MRA proved to be superior in visualization of smaller intracranial arteries, all pre-interventionally relevant information could be perceived from DSCT. DSCT and MRA may both be regarded as a reliable, fast, pre-interventional imaging investigation in patients with carotid artery stenosis.

Unusual malignant coronary artery anomaly: results of coronary angiography, MR imaging, and multislice CT.

We report the case of a man with an uncommon anomaly of the origin and course of the left coronary artery. Clinical, coronary angiography, magnetic resonance imaging, and multislice computed tomography findings of this intermittently symptomatic 49 year-old patient with the rare anomaly of his left coronary artery stemming from the right sinus of Valsalva and taking an interarterial and intraseptal course are presented. The diagnostic value of the different imaging modalities is discussed.

Radiofrequency ablation of liver metastases-software-assisted evaluation of the ablation zone in MDCT: tumor-free follow-up versus local recurrent disease.

The purpose of this study was to investigate differences in change of size and CT value between local recurrences and tumor-free areas after CT-guided radiofrequency ablation (RFA) of hepatic metastases during follow-up by means of dedicated software for automatic evaluation of hepatic lesions. Thirty-two patients with 54 liver metastases from breast or colorectal cancer underwent triphasic contrast-enhanced multidetector-row computed tomography (MDCT) to evaluate hepatic metastatic spread and localization before CT-guided RFA and for follow-up after intervention. Sixteen of these patients (65.1 + or - 10.3 years) with 30 metastases stayed tumor-free (group 1), while the other group (n = 16 with 24 metastases; 62.0 + or - 13.8 years) suffered from local recurrent disease (group 2). Applying an automated software tool (SyngoCT Oncology; Siemens Healthcare, Forchheim, Germany), size parameters (volume, RECIST, WHO) and attenuation were measured within the lesions before, 1 day after, and 28 days after RFA treatment. The natural logarithm (ln) of the quotient of the volume 1 day versus 28 days after RFA treament was computed: lnQ1//28/0(volume). Analogously, ln ratios of RECIST, WHO, and attenuation were computed and statistically evaluated by repeated-measures ANOVA. One lesion in group 2 was excluded from further evaluation due to automated missegmentation. Statistically significant differences between the two groups were observed with respect to initial volume, RECIST, and WHO (p < 0.05). Furthermore, ln ratios corresponding to volume, RECIST, and WHO differed significantly between the two groups. Attenuation evaluations showed no significant differences, but there was a trend toward attenuation assessment for the parameter lnQ28/0(attenuation) (p = 0.0527), showing higher values for group 1 (-0.4 + or - 0.3) compared to group 2 (-0.2 + or - 0.2). In conclusion, hepatic metastases and their zone of coagulation necrosis after RFA differed significantly between tumor-free and local-recurrent ablation zones with respect to the corresponding size parameters. A new parameter (lnQ1//28/0(volume/RECIST/WHO/attenuation)) was introduced, which appears to be of prognostic value at early follow-up CT.

Effect of different saline chaser volumes and flow rates on intravascular contrast enhancement in CT using a circulation phantom.

PURPOSE: To evaluate the influence of different saline chaser volumes and different saline chaser flow rates on the intravascular contrast enhancement in MDCT. MATERIALS AND METHODS: In a physiological flow phantom contrast medium (120 ml, 300 mgI/ml, Ultravist 300) was administered at a flow rate of 6 ml/s followed by different saline chaser volumes (0, 30, 60 and 90 ml) at the same injection rate or followed by a 30-ml saline chaser at different injection rates (2, 4, 6 and 8 ml/s). Serial CT-scans at a level covering the pulmonary artery, the ascending and the descending aorta replica were obtained. Time-enhancement curves were computed and both pulmonary and aortic peak enhancement and peak time were determined. RESULTS: Compared to contrast medium injection without a saline chaser the pushing with a saline chaser (30, 60, and 90 ml) resulted in a statistically significant increased pulmonary peak enhancement (all p=0.008) and prolonged peak time (p=0.032, p=0.024 and p=0.008, respectively). Highest aortic peak enhancement values were detected for a saline chaser volume of 30 ml. A saline chaser flow rate of 8 ml/s resulted in the highest pulmonary peak enhancement values compared to flow rates of 2, 4 and 6 ml/s (all p=0.008). Aortic peak enhancement showed the highest values for a flow rate of 6 ml/s. CONCLUSION: A saline chaser volume of 30 ml and an injection rate of 6 ml/s are sufficient to best improve vascular contrast enhancement in the pulmonary artery and the aorta in MDCT.

Global left ventricular function: assessment with dual-source CT versus conventional ventriculography in a porcine model.

OBJECTIVE: Cardiac computed tomography (CT) and conventional biplane ventriculography are established methods for the determination of ventricular function. Recently dual source CT was introduced for cardiac CT scanning providing a temporal resolution of 83 ms independent of the patient's heart rate. The purpose of this study was to assess the global left ventricular function using retrospectively ECG-gated dual source computed tomography (DSCT) in comparison to conventional ventriculography. METHODS AND RESULTS: Contrast-enhanced cardiac DSCT and conventional ventriculography were performed in 10 domestic pigs with an approximate weight of 60 kg using standardized examination protocols under general anaesthesia. From manually drawn endocardial contours, LV end-systolic (ESV) and end-diastolic volume (EDV), stroke volume (SV), ejection fraction (EF) were calculated by means of dedicated analysis software separately for both examination modalities. LV functional parameters were analysed using Bland-Altman plots, Student t-test, and Pearson correlation coefficient. Left ESV and EDV determined with DSCT correlated well with conventional ventriculography results (ESV: r = 0.86; EDV: r = 0.72) with a good correlation also for SV (r = 0.67).An only moderate correlation was found for EF (r = 0.52). Student t-test showed a significant underestimation of SV and EF derived from DSCT in comparison to ventriculography. CONCLUSION: Retrospectively ECG-gated DSCT can accurately determine LV volumes in comparison to conventional ventriculography but provides lower SV and EF values; however, the correlation was only moderate.