An accurate 5D potential energy surface for H3O+-H2 interaction

Modeling of the observational spectra of H₃O⁺ allows for a detailed understanding of the interstellar oxygen chemistry. While its spectroscopy was intensively studied earlier, our knowledge about the collision of H₃O⁺ with the abundant colliders in the interstellar medium is rather limited. In order to treat these collisional excitation processes, it is first necessary to calculate the potential energy surface (PES) of the interacting species. We have computed the five-dimensional rigid-rotor PES of the H₃O⁺-H₂ system from the explicitly correlated coupled-cluster theory at the level of singles and doubles with perturbative corrections for triple excitations [CCSD(T)-F12] with the moderate-size augmented correlation-consistent valence triple zeta (aug-cc-pVTZ) basis set. The well depth of the PES is found to be rather large, about 1887.2 cm^-1. The ab initio potential was fitted over an angular expansion in order to effectively use it in quantum scattering codes. As a first application, we computed dissociation energies for the different nuclear spin isomers of the H₃O⁺-H₂ complex.

Evaluating One Health: the role of team science in multisectoral collaboration

In a review of the literature surrounding One Health, cross-boundary collaboration, the science of teams, and interdisciplinary health competencies, many individual disciplines, and in some cases multidisciplinary research teams, have looked at the scholarship of collaboration and arrived at remarkably similar conclusions as to which factors and competencies support effective collaboration. However, conclusions on how to effectively evaluate collaboration are consistently lacking across the literature reviewed. Although important advances have been made recently in the area of evaluating One Health operations and outcomes, there is an opportunity to develop process-based performance measures for One Health collaboration and teamwork. Synthesising work on collaborative performance evaluation across multiple disciplinary and sectoral lanes and levels of collaborative analysis, the authors argue that, in addition to outcome-based One Health evaluation, the evaluation of One Health processes needs to be further refined and 'team' effectiveness needs to be evaluated at all levels of the health system: individual, organisational and network.

DW-MRI of liver lesions: can a single ADC-value represent the entire lesion?

AIM

To evaluate whether focal liver lesions (FLLs) exhibit a homogeneous appearance on apparent diffusion coefficient (ADC) maps and whether there is inter-section variation in the calculated ADC values of FLLs (inter-section range).

MATERIALS AND METHODS

Eighty-eight patients with 128 FLLs (70 benign, 58 malignant) who underwent abdominal magnetic resonance imaging (MRI) including diffusion-weighted (DW)-MRI were included. Two observers evaluated variation of signal intensity of each FLL within each ADC map image (intra-section) and among different ADC map images through the lesion (inter-section). ADC values of each FLL and neighbouring liver parenchyma were measured on all sections. The inter-section range of FLLs was compared with the neighbouring liver parenchyma.

RESULTS

Intra-section inhomogeneity was noted in 39.8% (97/244 sections) and 38.9% (95/244) of benign lesions, and 61% (114/187 sections) and 61.5% (115/187) of malignant lesions, by observer 1 and observer 2, respectively. Inter-section inhomogeneity was noted in 25.7% (18/70) and 27.1% (19/70) of benign lesions, and 51.7% (30/58) and 50% (29/58) of malignant lesions, by observer 1 and observer 2, respectively. The inter-section range for both benign (0.28 × 10(-3) mm(2)/s) and malignant (0.25 × 10(-3) mm(2)/s) FLLs were significantly greater than that of liver parenchyma surrounding benign (0.16 × 10(-3) mm(2)/s, p < 0.001) and malignant (0.14 × 10(-3) mm(2)/s, p = 0.01) FLLs.

CONCLUSION

Due to intra-/inter-section variations in ADC values of benign and malignant FLLs, a single ADC value may not reliably represent the entire lesion.

[Importance of PET/CT for imaging of colorectal cancer]

CLINICAL/METHODICAL ISSUE

Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has emerged as a very useful imaging modality in the management of colorectal carcinoma. Data from the literature regarding the role of PET/CT in the initial diagnosis, staging, radiotherapy planning, response monitoring and surveillance of colorectal carcinoma is presented. Future directions and economic aspects are discussed.

STANDARD RADIOLOGICAL METHODS

Computed tomography (CT), magnetic resonance imaging (MRI) and FDG-PET for colorectal cancer and endorectal ultrasound for rectal cancer.

METHODICAL INNOVATIONS

Combined FDG-PET/CT.

PERFORMANCE

While other imaging modalities allow superior visualization of the extent and invasion depth of the primary tumor, PET/CT is most sensitive for the detection of distant metastases of colorectal cancer.

ACHIEVEMENTS

We recommend a targeted use of PET/CT in cases of unclear M staging, prior to metastasectomy and in suspected cases of residual or recurrent colorectal carcinoma with equivocal conventional imaging. The role of PET/CT in radiotherapy planning and response monitoring needs to be determined. Currently there is no evidence to support the routine use of PET/CT for colorectal screening, staging or surveillance.

PRACTICAL RECOMMENDATIONS

To optimally exploit the synergy between morphologic and functional information, FDG-PET should generally be performed as an integrated FDG-PET/CT with a contrast-enhanced CT component in colorectal carcinoma.

Dual-Source computed tomography of the chest in the surgical planning of repeated cardiac surgery

AIM

When reoperative cardiac surgery is indicated, detailed, three-dimensional imaging of the thorax permits accurate depiction of cardiac anatomy and vascular structures potentially increasing the safety of the surgical procedure. We sought to evaluate the contribution of dual-source multidetector-row computed tomography (DSCT) of the heart and thorax in planning repeated open heart surgery.

METHODS

Twenty-eight patients (mean age, 68 years) scheduled for repeated cardiac surgery who had undergone previous coronary artery bypass grafting (n=19) or cardiac valve replacement (8) or combined valvular and bypass surgery (1) underwent contrast-enhanced ECG-gated DSCT (Somatom Definition, Siemens Medical Solutions) of the whole thorax with a temporal resolution of 82 ms and a spatial resolution of 0.4 mm³. The indication for repeated surgery was bypass surgery (N.=6), valve replacement (16), combined bypass and valvular surgery (5) or other reasons (1). Assessment of surgical risk based on DSCT data were performed in terms of the relation of the ascending aorta and cardiac structures to the expected median sternotomy line, graft patency and anatomic course, and the degree of calcification of the ascending aorta and coronary arteries.

RESULTS

DSCT findings led to a change of surgical approach for 9/28 (32.1%) patients (non-midline incision, N.=3; surgery performed under circulatory arrest, N.=5; peripheral arterial cannulation before sternotomy, N.=1) and cancellation of surgery for 4/28 (14.3%) patients (heavy aortic and coronary calcifications impeding bypass surgery, N.=2; right heart or aortic aneurysm in close proximity to the sternum in high risk patients, N.=2). The planned surgical approach remained unchanged after DSCT for the remaining15/28 (53.6%) patients. Of 54 bypass graft conduits (20 arterial, 34 venous) visualized on DSCT in 20 patients after previous bypass grafting, 16 arterial and 24 venous grafts were patent, while 4 arterial and 10 venous grafts were occluded.

CONCLUSION

DSCT of the heart and thorax is an effective, non-invasive tool for the preoperative planning of repeated cardiac surgery. The technique provides significant information to modify the surgical approach and may increase the safety of the procedure.

FDG-PET-CT and whole-body MRI for triage in patients planned for radioembolisation therapy

PURPOSE

The purpose was to evaluate the potential of FDG-PET-CT and whole-body MRI (WB-MRI) as diagnostic triage methods for patients planned for radioembolisation of metastatic liver disease.

MATERIALS AND METHODS

135 patients with multifocal liver metastases were evaluated for potential palliative therapy with radioembolisation using 90-Yttrium microspheres. All patients were examined consecutively with FDG-PET-CT and WB-MRI for exclusion of relevant extra-hepatic tumor manifestations. All patients underwent 99mTc-albumine angiography followed by scintigraphy to exclude significant hepato-pulmonary shunting.

RESULTS

Out of the 135 patients included into the pre-therapeutic diagnostic algorithm, 56% were eligible and received radioembolisation, while 44% could not be treated. In 91% the exclusion criteria was diagnosis of significant extra-hepatic metastatic disease. In 85% exclusion diagnosis was made concordantly by both FDG-PET-CT and WB-MRI, in 9% diagnosis was provided by PET-CT, in 6% by WB-MRI alone. Patient-based sensitivity for detection of extra-hepatic disease was 94% for PET-CT and 91% for WB-MRI. False-positive diagnosis of extrahepatic disease leading to exclusion for radioembolisation therapy was made in 2% of patients, in one patient by PET-CT and in one patient by WB-MRI alone. Overall, specificity for inclusion of radioembolisation therapy by combining both modalities was 99%. In 9% of patients angiographic diagnosis made radioembolisation impossible, in 7% solely the angiographic findings were decisive.

CONCLUSION

Both FDG-PET-CT and WB-MRI are efficient diagnostic triage methods for patients planned for radioembolisation of liver metastases. Overall, FDG-PET-CT shows a trend to higher diagnostic accuracy compared to WB-MRI and may be used as imaging method of choice as a standalone examination. In combination, both modalities exhibited high sensitivity for the diagnosis of extra-hepatic tumor manifestations and result in high specificity.

[Whole-body MRI and FDG-PET/CT imaging diagnostics in oncology]

The advent of whole-body MRI (WB-MRI) has introduced a systemic approach to oncologic imaging compared to established sequential, multi-modal diagnostic algorithms. Hardware innovations, such as whole-body scanners at 1.5 Tesla and also recently 3 Tesla, combined with acquisition acceleration techniques, have made WB-MRI clinically feasible. With this method dedicated assessment of individual organs with various soft tissue contrast, high spatial resolution and contrast media dynamics can be combined with whole-body anatomic coverage.PET/CT has established itself as a powerful modality in the staging of patients suffering from malignant tumors. In addition to the morphologic information provided by the CT component of this hybrid modality, the PET component contributes invaluable metabolic information, which greatly enhances accuracy in the assessment of lymphatic spread and viability of tumor tissue. Whole-body MR diffusion imaging is a novel and promising technique which may contribute to superior sensitivity in the detection of tumor manifestations. In the assessment of distant metastatic spread WB-MRI is highly sensitive and has advantages over PET/CT, especially in those tumors frequently spreading to the liver, bone or brain. WB-MRI is also very attractive as a radiation-free alternative for imaging of pediatric tumor patients in whom multiple follow-up examinations may be required.WB-MRI allows for precise assessment of the bone marrow and has been proven to be highly accurate for the staging of hematologic diseases, such as multiple myeloma. In this article recent developments and applications of WB-MRI in oncologic imaging are addressed and compared to the results of PET/CT.

[Quantification of immunohistochemical expression of somatostatin receptors in neuroendocrine tumors using 68Ga-DOTATATE PET/CT]

PURPOSE

The immunohistochemical expression of somatostatin receptor (SSTR) subtype 2 was compared to quantitative (68)Ga-DOTATATE PET in neuroendocrine tumors (NET).

MATERIAL AND METHODS

In 27 patients suffering from metastatic NET the expression of somatostatin receptors (SSTR, score 0-3) and the Ki-67 index were assessed. The immunohistochemical findings were compared with the (68)Ga-DOTATATE PET uptake in these tumors using the SUV(max) (standardized uptake value). Both values were compared with the Ki-67 proliferation index.

RESULTS

The SUV(max) in NET without SSTR expression was significantly lower compared to those with SSTR expression (p <0.05), even though 3 out of 5 NETs with a score of 0 showed a high uptake of (68)Ga-DOTATATE. The SUV(max) correlated significantly (r=0.40, p <0.05) with the score of immunohistochemical SSTR expression (negative, score 0, moderate, score 1 and high, scores 2 and 3). The Ki-67 index correlated inversely with the SSTR expression score (r=-0.42, p <0.05), but not significantly with the SUV(max) (r=-0.33, p=0.11).

CONCLUSION

(68)Ga-DOTATATE uptake was moderately correlated with the results of immunohistochemical SSTR analyses. However, SSTR negative NET may show high uptake of (68)Ga-DOTATATE.

[Combined functional and morphological imaging of sarcomas: significance for diagnostics and therapy monitoring]

(18)F-fluorodeoxyglucose positron-emission tomography (FDG-PET) and especially hybrid FDG-PET/CT is becoming more and more accepted for the clinical management of adult and pediatric patients with sarcomas. By integrating the CT component the specificity in particular but also the sensitivity of the modality are improved further. With PET/CT a complete staging including the detection of lung metastases is feasible in a single examination. For patients with primary bone and soft tissue sarcomas FDG-PET/CT is utilized for diagnosis, staging and restaging, metabolic tumor grading, guidance of biopsies, detection of tumor recurrence and therapy monitoring. Furthermore, it has been demonstrated that FDG uptake of the tumor prior to treatment and changes of FDG uptake after therapy significantly correlate with histopathologic response and survival of patients. Therefore, PET and PET/CT have a prognostic value. In the future new perspectives of hybrid PET/CT imaging will arise by introducing novel radiotracers and combined functional imaging of tumor metabolism and perfusion. High resolution MRI is essential for local evaluation of the primary tumor and preoperative planning with assessment of possible infiltration of vascular or neural structures. Contrast-enhanced MRI remains a key tool in the diagnosis of recurrent disease, especially in tumors which are not hypermetabolic. Dynamic contrast-enhanced MR sequences can significantly contribute to therapy monitoring. More research is necessary to prospectively compare dynamic contrast-enhanced MRI and FDG-PET/CT for evaluation of local and recurrent diseases.

Quantitative assessment of left ventricular function with dual-source CT in comparison to cardiac magnetic resonance imaging: initial findings

Cardiac magnetic resonance imaging and echocardiography are currently regarded as standard modalities for the quantification of left ventricular volumes and ejection fraction. With the recent introduction of dual-source computedtomography (DSCT), the increased temporal resolution of 83 ms should also improve the assessment of cardiac function in CT. The aim of this study was to evaluate the accuracy of DSCT in the assessment of left ventricular functional parameters with cardiac magnetic resonance imaging (MRI) as standard of reference. Fifteen patients (two female, 13 male; mean age 50.8 +/- 19.2 years) underwent CT and MRI examinations on a DSCT (Somatom Definition; Siemens Medical Solutions, Forchheim, Germany) and a 3.0-Tesla MR scanner (Magnetom Trio; Siemens Medical Solutions), respectively. Multiphase axial CT images were analysed with a semiautomatic region growing algorithms (Syngo Circulation; Siemens Medical Solutions) by two independent blinded observers. In MRI, dynamic cine loops of short axis slices were evaluated with semiautomatic contour detection software (ARGUS; Siemens Medical Solutions) independently by two readers. End-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF) and stroke volume (SV) were determined for both modalities, and correlation coefficient, systematic error, limits of agreement and inter-observer variability were assessed. In DSCT, EDV and ESV were 135.8 +/- 41.9 ml and 54.9 +/- 29.6 ml, respectively, compared with 132.1 +/- 40.8 ml EDV and 57.6 +/- 27.3 ml ESV in MRI. Thus, EDV was overestimated by 3.7 ml (limits of agreement -46.1/+53.6), while ESV was underestimated by 2.6 ml (-36.6/+31.4). Mean EF was 61.6 +/- 12.4% in DSCT and 57.9 +/- 9.0% in MRI, resulting in an overestimation of EF by 3.8% with limits of agreement at -14.7 and +22.2%. Rank correlation rho values were 0.81 for EDV (P = 0.0024), 0.79 for ESV (P = 0.0031) and 0.64 for EF (P = 0.0168). The kappa value of inter-observer variability were amounted to 0.85 for EDV, ESV and EF. DSCT offers the possibility to quantify left ventricular function from coronary CT angiography datasets with sufficient diagnostic accuracy, adding to the value of the modality in a comprehensive cardiac assessment. The observed differences in the measured values may be due to different post-processing methods and physiological reactions to contrast material injection without beta-blocker medication.

[Quantification of coronary artery stenoses: comparison of 64-slice and dual source CT angiography with cardiac catheterization]

BACKGROUND

Until now stenoses of the coronary arteries have been evaluated visually with CT angiography. Therefore, the results were highly dependent on subjective factors inherent in the examiner. New software tools for semiquantitative analysis (CT-QCA, quantitative coronary assessment) might be adequate to improve the diagnostic accuracy und reproducibility.

MATERIAL AND METHODS

CTAs of 20 patients were analyzed. Ten patients each were evaluated using 64-slice CT (64SCT) and dual source CT (DSCT) (Somatom Sensation 64 and Somatom Definition, Siemens Medical Solutions, Forchheim), respectively. Two radiologists independently evaluated the data visually and with the help of a software tool (Syngo Circulation, Siemens Medical Solutions, Forchheim). The results of the quantitative assessment of the invasive heart catheterization served as the reference standard. Sensitivity and specificity as well as the correlation coefficient, the systematic error, and the interobserver agreement (kappa) were determined.

RESULTS

In each of both patient groups 12 stenoses were detected. For the detection of stenoses >75%, sensitivity and specificity for the visual evaluation using the 64SCT were 100% and 90%, and with the CT-QCA both were 100%. For the DSCT sensitivity and specificity were 100% for both the visual and semiautomated evaluation. The Bland-Altman plot of the results of the 64SCT showed an overestimation of 3.3% (+/-62.7%/56.2%) compared to the heart catheterization. The results of the DSCT exhibited an overestimation of 6.2% (+/-33.1%/19.8%). The interobserver agreement of the CT-QCA and the visual evaluation showed a kappa value of 0.75 and for DSCT of 1.0.

CONCLUSION

The results showed a good correlation of grading stenosis between the software-assisted evaluation and the results of the coronary catheter angiography. The promising results of the DSCT are due to a superior temporal resolution compared to the 64SCT. Confirmation of these data by trials in larger patient collectives is warranted.

Dual-source-CT in der Diagnostik des Thoraxschmerzes

BACKGROUND

With the depiction of pulmonary arteries, coronary arteries, and the aorta, CT angiography of the chest offers a comprehensive diagnostic work-up of unclear chest pain. The aim of this study was to assess the diagnostic accuracy of dual-source CT in this patient group.

MATERIALS AND METHODS

A total of 47 patients suffering from unclear chest pain were examined with a Siemens Somatom Definition. Volume and flow of contrast media (Ultravist, Schering) were adapted to the body weight. The examinations were evaluated with regard to image quality and contrast opacification and to the diagnostic accuracy with reference to the final clinical diagnosis.

RESULTS

Adequate contrast opacification was achieved in all examinations. The depiction of the coronary arteries was diagnostic in all cases. The cause of chest pain could be identified in 41 cases. Among the diagnoses were coronary and myocardial pathologies, valvular disease, aortic aneurysms and dissections, pulmonary embolism, and pneumonic consolidation.

CONCLUSION

DSCT angiography of the chest offers a very good image quality even at high heart rates so that a high diagnostic accuracy is achieved in patients with acute chest pain.

Einsatz der Dual-source-Computertomographie in der prä- und postoperativen kardiochirurgischen Diagnostik

PURPOSE

The aim of this study was to evaluate the clinical potential of dual-source computed tomography (DSCT) in pre- and postsurgical diagnostics in the field of cardiac surgery.

MATERIAL AND METHODS

A total of 20 patients underwent DSCT of the heart. This CT system with two rotating X-ray tubes (Somatom Definition, Siemens Medical Solutions, Forchheim, Germany) achieves a temporal resolution of 83 ms and a spatial resolution of 0.4 x 0.4 x 0.4 mm. The patient cohort consisted of two subgroups. In a group of ten patients with known coronary artery disease (CAD), scheduled for bypass surgery (i.e., high pretest likelihood for having significant CAD), the results of DSCT coronary angiography (CTA) and invasive quantitative catheter angiography (QCA) were compared to assess the diagnostic accuracy of DSCT in the detection of significant coronary artery stenoses (>50%). In a second group of ten patients with previous aortic valve replacement (homografts), the valve opening area of the transplanted aortic valve graft was measured by DSCT and compared with echocardiography as a standard of reference to exclude postsurgical restenosis of the valve.

RESULTS

Of 150 coronary artery segments depicted by CT, 144 (96%) were classified as "assessable." A significant CAD was known in all patients, and altogether 43 significant stenoses were present according to the results of QCA. Blinded to these results, DSCTA reached a sensitivity and specificity of 95% (41/43) and 93% (103/111), yielding a positive and negative predictive value (PPV, NPV) of 79% (31/39) and 98% (103/105), respectively. In patients with aortic valve homografts, all DSCT datasets were considered as being of diagnostic image quality concerning valve depiction. The planimetric evaluation of the CT data as compared to results of echocardiography showed a significant correlation of the results (r=0.64, p=0.0467). A high-grade valve stenosis (opening area <1.0 cm(2)) could be correctly excluded by DSCT in all patients.

CONCLUSIONS

Dual-source CT shows great diagnostic potential in patients before or after cardiac surgery. DSCT provides a high diagnostic accuracy for detection of coronary artery stenosis before bypass surgery. DSCT also proved to be accurate in the assessment of patients who received aortic valve replacement.

[Magnetic resonance imaging for the assessment of myocardial perfusion: value of various semiquantitative perfusion parameters]

PURPOSE

The aim of this study was to determine the diagnostic accuracy of various semiquantitative perfusion parameters of the magnetic resonance perfusion examination of the myocardium compared to conventional coronary angiography.

PATIENTS, MATERIAL AND METHODS

Twenty patients with suspicion of coronary artery disease who underwent coronary angiography were examined by MR imaging within 14 days before or after coronary angiography. A perfusion examination during adenosine application (140 microg/kg/min) and at rest was performed using a saturation recovery turboFLASH sequence. The semi-quantitative parameters maximum signal intensity (SIM), time-to-peak (TTP), area under the curve (AUC) and upslope (US) were determined using dedicated software (Dynamic Signal Analysis, ARGUS, Siemens Medical Solutions) for the evaluation of the signal-intensity-time curves. In addition, the ratio of these parameters (MPRI: myocardial perfusion reserve index) were determined by dividing the values of the stress examination by the values of the rest examination.

RESULTS

Accuracy was 78.4% (SIM), 64.9% (TTP), 64.2% (AUC) and 70.4% (US) for the evaluation of the stress examination. Accuracy for the MPRI of the semi-quantitative parameters was 72.2% (SIM), 50.9% (TTP), 72.2% (AUC) und 89.1% (US).

CONCLUSION

A combined semi-quantitative evaluation of the MPRI values using the ratio of the upslope values of the stress and rest examination was shown to be the most accurate method. MPRI (US(Stress)/US(Rest)) is superior to an evaluation of the stress examination alone.

[Evaluating multislice computed tomography for imaging coronary atherosclerosis]

PURPOSE

The purpose of this study was the evaluation of multidetector-row computed tomography (MDCT) for the assessment of atherosclerotic coronary artery vessel wall changes.

METHODS

In an ex vivo study, 17 human hearts were scanned with MDCT and results were compared to histopathology. Morphologic imaging criteria of MDCT for various plaque-types were developed. In a following in vivo study, 94 coronary MDCT angiograms (MDCTA) of patients with suspected coronary artery disease (CAD) were reviewed retrospectively, assessing the diagnostic value of the coronary MDCTA, and determining the number and correlations of the various plaques types as described in the ex vivo study. Additionally, volumetry of calcified and noncalcified plaque components was performed.

RESULTS

In the ex vivo study, MDCT showed a high sensitivity for calcified and non-calcified plaques. Comparing the results with histopathology, characteristic image criteria could be determined for lipid-rich, fibrous and calcified plaque components. Reviewing the contrastenhanced in-vivo MDCT coronary angiographies, presence of noncalcified plaques was proven in 38% of the patients. In 5 patients with a calcium score of 0, presence of coronary atherosclerosis was proven in the contrastenhanced scan.

CONCLUSIONS

MDCT is able to differentiate various plaque components in an ex vivo setting as well as invivo. Contrastenhanced MDCT of the coronary arteries allows for the detection of noncalcified plaques. In vivo volumetry of noncalcified plaques is feasible.

Indikationen f�r die Mehrschicht-CT-Angiographie der Koronararterien

INTRODUCTION

The newest generation of 16-detector-row CT allows displaying the anatomy and assessment of coronary artery disease (CAD) when slow regular sinus rhythm is present.

METHODS

For morphological assessment of cardiac structures by using Multi-detector row CT a dedicated scan protocol is obligatory. The indication for coronary CT angiography (CTA) is currently under investigation by several study groups.

RESULTS

Because of the limited spatial and temporal resolution and coronary calcium artefacts, it is not possible with multislice CT angiography to assess coronary arteries in patients with established coronary artery disease. The anatomy of the coronary arteries can well be displayed with this technique.

CONCLUSION

The high negative predictive value of coronary CTA may justify the investigation of symptomatic patients with intermediate pretest probability of CAD. Moreover coronary CTA is suitable for patients for displaying the origin and course of abnormal coronary arteries.

EKG-gesteuerte Bypass-CT-Angiographie?Einsatz in der Darstellung arterieller Byp�sse

Nowadays coronary artery bypass grafting is increasingly performed using arterial grafts. Purpose of the study was the evaluation of a appropriate 16 detector-row CT angiography protocol in patients after predominantly arterial bypass grafting. Fourteen patients after bypass grafting were including into the study and CT angiography carried out in the early postoperative period using a 16 detector-row CT system. To reduce cardiac pulsation artifacts data acquisition was implemented using ECG-gating algorithms. Overall 43 grafts (37 arterial, 6 venous) were examined. In 13 patients surgery had been performed using composite grafts with T or TY configuration. The mean heart rate was 74.1 bpm and showed a negative correlation to the image quality (r=-0.65; p=0.01). However, all data sets were diagnostic. Contrast injection protocol allowed for a homogeneous opacification throughout the vessels of interest. All non-delineationable grafts (5) showed a close proximity to the heart (T or Y grafts). Cardiac surgery is increasingly focusing on arterial revascularisation in bypass grafting and therefore leading to new demands for non-invasive bypass graft imaging. 16 detector-row CT allows a reliable visualization of even composite arterial grafts. However, for detection of grafts in the proximity of the heart a reduction of the heart rate (<65-70) still seems to be necessary.

C-reactive protein in the arterial intima: role of C-reactive protein receptor-dependent monocyte recruitment in atherogenesis

Infiltration of monocytes into the arterial wall is an early cellular event in atherogenesis. Recent evidence shows that C-reactive protein (CRP) is deposited in the arterial intima at sites of atherogenesis. In this study, we demonstrate that CRP deposition precedes the appearance of monocytes in early atherosclerotic lesions. CRP is chemotactic for freshly isolated human blood monocytes. A specific CRP receptor is demonstrated on monocytes in vitro as well as in vivo, and blockage of the receptor by use of a monoclonal anti-receptor antibody completely abolishes CRP-induced chemotaxis. CRP may play a major role in the recruitment of monocytes during atherogenesis.

Thrombotic thrombocytopenic purpura in a patient with genetic haemochromatosis, liver cirrhosis and an iron-free focus

We report a patient with thrombotic thrombocytopenic purpura and genetic haemochromatosis. The patient was shown by the polymerase chain reaction to be homozygous for the Cys282Tyr mutation of the HFE gene. Liver biopsy showed micronodular cirrhosis and the presence of an iron-free focus which was thought to be pre-neoplastic.

Continuous intravenous infusion of high-dose recombinant interleukin-2 for acute myeloid leukaemia--a phase II study

A group of 13 patients with acute myeloid leukaemia of differing disease status were treated with continuous intravenous infusion of high-dose recombinant interleukin-2 (rIL-2). There was up-regulation of the cellular cytotoxic functions in all these patients following the rIL-2 therapy, with increase in the natural killer (NK) activity, lectin-dependent cellular cytotoxicity, induction of cytotoxicity-linked cytoplasmic serine esterase and lymphocyte activation. However, the clinical response to rIL-2 in these patients was disappointing, especially in patients treated in frank relapse. Although 1 patient treated in early second relapse achieved a third complete remission, the duration of the remission was brief and lasted only 6 months. Adverse reactions among these patients were common. Whether or not lymphokine-activated killer cells are needed to improve the response rate over rIL-2 alone in these patients deserves further investigation.