Early whole-body CT for treatment guidance in patients with return of spontaneous circulation after cardiac arrest.

PURPOSE: Non-traumatic cardiac arrest (CA) and return of spontaneous circulation (ROSC) after cardiopulmonary resuscitation (CPR) are often associated with multiple pathologies. Expecting a high prevalence of important findings, a whole-body CT (WBCT) could be of relevance for therapy. The aim of this study is to investigate the feasibility and diagnostic yield of an early WBCT in this setting. METHODS: This single-center retrospective study included 100 consecutive patients (27 female; 73 male; mean age 68.5± 12.57 years) with non-traumatic, in- and out-of-hospital CA and ROSC following CPR, who underwent a contrast-enhanced WBCT within 6 h after ROSC over 12 months. CT findings were determined corresponding to anatomical region. RESULTS: Early WBCT was successfully carried out in 100% of the patients with CA and ROSC after CPR. Acute pathologies were found not only in the chest but also in the head (15%) and the abdomen (6%). Early global brain edema (n = 12), acute stroke (n = 3), pulmonary embolism (n = 10), pneumothorax (26%), acute abdominal pathologies (n = 6), iatrogenic bleeding (4%), and CPR-related injuries (93%) were detected by CT right from the beginning of the post-cardiac arrest care. CONCLUSIONS: An early WBCT is feasible and provides added diagnostic value for patients with ROSC after non-traumatic CA.

Preoperative Imaging Overestimates the Tumor Size in Pancreatic Neuroendocrine Neoplasms Associated with Multiple Endocrine Neoplasia Type 1.

BACKGROUND: Radiological tumor size of non-functioning pancreatic neuroendocrine neoplasms (Nf-pNENs) associated with multiple endocrine neoplasia type 1 (MEN1) is a crucial parameter to indicate surgery. The aim of this study was to compare radiological size (RS) and pathologic size (PS) of MEN1 associated with pNENs. METHODS: Prospectively collected data of MEN1 patients who underwent pancreatic resections for pNENs were retrospectively analyzed. RS was defined as the largest tumor diameter measured on endoscopic ultrasound (EUS), magnetic resonance imaging (MRI) or computed tomography (CT). PS was defined as the largest tumor diameter on pathological analysis. Student's t test and linear regression analysis were used to compare the median RS and PS. p < 0.05 was considered significant. RESULTS: Forty-four patients with a median age of 37 (range 10-68) years underwent primary pancreatic resections for pNENs. Overall, the median RS (20 mm, range 3-100 mm) was significantly larger than the PS (13 mm, range 4-110 mm) (p = 0.001). In patients with pNENs < 20 mm (n = 27), the size difference (median RS 15 mm vs PS 12 mm) was also significant (p = 0.003). However, the only modality that significantly overestimated the PS was EUS (median RS 14 mm vs 11 mm; p = 0.0002). RS overestimated the PS in 21 patients (21 of 27 patients, 78%). Five of 11 patients (12%) with a Nf-pNEN and a RS > 20 mm had in reality a PS < 20 mm. MRI was the imaging technique that best correlated with PS in the total cohort (r = 0.8; p < 0.0001), whereas EUS was the best correlating imaging tool in pNENs < 20 mm (r = 0.5; p = 0.0001). CONCLUSION: Preoperative imaging, especially EUS, frequently overestimates the size of MEN1-pNENs, especially those with a PS < 20 mm. This should be considered when indicating surgery in MEN1 patients with small Nf-pNENs.

Vascular closure devices after endovascular procedures in swine: a reliable method?

PURPOSE: To investigate the safety and feasibility of the use of a vascular closure device (VCD) after endovascular procedures in swine. MATERIAL AND METHODS: In a study on endovascular therapy, VCD (StarClose, Abbott Vascular, Il, USA) was used in 20 female swines to achieve immediate hemostasis after percutaneous right femoral artery (FA) access. 10 animals were sacrificed immediately after the study and 10 animals were sacrificed 28 days after the initial study. To ensure complete hemostasis and patency of the femoral artery, a CT-angiography of the puncture site was performed on day 1 (acute and chronic group) and day 28 (chronic group). After the sacrifice, the femoral artery was explanted and examined macroscopically for signs of VCD dysfunction. RESULTS: Technical success rate was 100% with immediate hemostasis being achieved in all animals. No animals showed evidence of hematoma. During explantation, only small traces of coagulated blood were found in the acute group, while there were no signs of hematoma in the chronic group. CT-angiography immediately after VCD application as well as before sacrifice (chronic group) showed patency of the FA in all cases. CONCLUSION: The use of VCD to achieve hemostasis after endovascular studies in swine is feasible and safe.

[Invasive procedure for clarification of pulmonary nodules]. / Invasive Verfahren zur Abklärung pulmonaler Rundherde.

CLINICAL/METHODICAL ISSUE: The management of solitary lung nodules poses a common clinical problem and biopsy is oftten required. Several guidelines provide slightly different recommendations and there are no uniform recommendations regarding the ideal technique of puncture guidance (e.g. percutaneous versus bronchoscopic or thoracoscopic). STANDARD RADIOLOGICAL METHODS: Fine needle aspiration biopsy (FNA) and core biopsy are well established techniques. Both can be performed under CT and to some extent ultrasound guidance. PERFORMANCE: Diagnostic accuracies of FNA and core biopsy for malignant lesions are around 95 %. Core biopsy is superior to FNA for establishing a specific diagnosis with a diagnostic yield of 81-88 % versus 17-21 %. ACHIEVEMENTS: In clinical routine practice core biopsy is the superior tool when compared to FNA. PRACTICAL RECOMMENDATIONS: Central lesions in close proximity to bronchi may be biopsied with endobronchial ultrasound (EBUS)-guided bronchoscopy. In all other lesions percutaneous, ideally CT-guided biopsy should be the method of first choice.

[Transarterial ablative therapy of hepatocellular carcinoma]. / Transarterielle ablative Therapien des hepatozellulären Karzinoms.

CLINICAL/METHODICAL ISSUE: Due to late diagnosis and a lack of organs only about 30 % of patients suffering from hepatocellular carcinoma (HCC) undergo curative treatment. STANDARD RADIOLOGICAL METHODS: Transarterial chemoembolization (TACE) is a routine procedure in intermediate stage HCC. In addition transarterial embolization (TAE) and transarterial radioembolization (TARE) are available for these patients. PERFORMANCE: For inoperable patients with HCC, TACE is superior to best supportive care in terms of survival. Combined with percutaneous ablation TACE achieves results similar to resection. ACHIEVEMENTS: Current developments, such as drug-eluting beads, TARE and multimodal treatment are well suited to further improve outcome in patients with intermediate stage HCC. PRACTICAL RECOMMENDATIONS: Transarterial therapies in HCC should be applied in accordance with the Barcelona Clinic Liver Cancer (BCLC) criteria. Due to a better safety profile and potentially improved disease-free survival the use of drug-eluting beads should be liberally considered.

Occupational orthopedic problems and its relation to personal radiation protection in interventional radiology.

PURPOSE: Several studies report occupational orthopedic problems among interventional cardiologists. These health problems are usually multifactorial. However, the personal protective equipment used should play a major role. An online survey was conducted to determine the frequency of such health problems among interventional radiologists and to correlate them with the use of personal radiation protective clothing. MATERIAL AND METHODS: An anonymous online survey that comprised of 17 questions was sent via e-mail to 1427 members of the German Society for Interventional Radiology (DeGIR) in Germany, Austria and Switzerland. The questions were focused on interventional workload, the use of personal radiation protection apparel and orthopedic problems. Given the different scale levels, the associations between the variables were analyzed using different statistical methods. A significance level of p < 0.05 was chosen. RESULTS: There were 221 survey responders (15.5% response rate). About half of responders (47.7%) suffered from more than five episodes of orthopedic problems during their interventional career. Lumbar spine was involved in 81.7% of these cases, cervical spine in 32.8%, shoulder in 28.5% and knee in 24.7%. Because of orthopedic problems, 16.1% of the responders had to reduce and 2.7% had to stop their interventional practice. The number of affected body regions correlates with the fit of the radiation protection means (p < 0.05, r = 0.135) and the reduction of activity as an interventional radiologist (p < 0.05, r = -0.148). CONCLUSION: Overall, the survey reveals widespread orthopedic problems at several body regions among interventional radiologists, associated with the fit of radiation protection systems, among other factors. A connection between the orthopaedic complaints and the radiation protection system used could not be established.

[Vena cava filter. Which indications remain in the era of differentiated anticoagulation?]. / Vena-cava-Filter. Welche Indikationen bleiben in Zeiten differenzierter Antikoagulation?

CLINICAL/METHODICAL ISSUE: Venous thromboembolism (VTE) is the third most common disease of the cardiovascular system. It is associated with a 30-day lethality in the range of 6  % in deep vein thrombosis and 12  % in pulmonary embolism (PE). There are various guidelines with sometimes controversial recommendations regarding the use of inferior vena cava (IVC) filters. STANDARD RADIOLOGICAL METHODS: Implantation of IVC filters is a standard therapy in selected patients with an estimated 259,000 filters implanted in 2012. METHODICAL INNOVATIONS: Optionally retrievable filters are increasingly being used in clinical routine practice. Future developments will include biodegradable and drug-eluting filters. PERFORMANCE: When compared to anticoagulation as the reference therapy of VTE, IVC filters will significantly reduce the frequency of symptomatic PE; however, there is no advantage in overall survival for either therapy. ACHIEVEMENTS: Despite different guidelines in clinical routine practice the use of IVC filters appears to depend on the individual clinical experience and assessment of the interventionalist. PRACTICAL RECOMMENDATIONS: Nowadays retrievable filters should be used although there are relevant differences between the various devices. As a matter of principle all IVC filters should be removed as soon as adequate anticoagulation can be established.

Reconstructions with identical filling (RIF) of the heart: a physiological approach to image reconstruction in coronary CT angiography.

OBJECTIVES: To compare image quality in coronary artery computed tomography angiography (cCTA) using reconstructions with automated phase detection and Reconstructions computed with Identical Filling of the heart (RIF). METHODS: Seventy-four patients underwent ECG-gated dual source CT (DSCT) between November 2009 and July 2010 for suspected coronary heart disease (n = 35), planning of transcatheter aortic valve replacement (n = 34) or evaluation of ventricular function (n = 5). Image data sets by the RIF formula and automated phase detection were computed and evaluated with the AHA 15-segment model and a 5-grade Likert scale (1: poor, 5: excellent quality). Subgroups regarding rhythm (sinus rhythm = SR; arrhythmia = ARR) and potential premedication were evaluated by a per-segment, per-vessel and per-patient analysis. RESULTS: RIF significantly improved image quality in 10 of 15 coronary segments (P < 0.05). More diagnostic segments were provided by RIF regarding the entire cohort (n = 693 vs. 590, P < 0.001) and all of the subgroups (e.g. ARR: n = 143 vs. 72, P < 0.001). In arrhythmic patients (n = 19), more diagnostic vessels (e.g. LAD: n = 10 vs. 3; P < 0.014) and complete data sets (n = 7 vs. 1; P < 0.001) were produced. CONCLUSIONS: RIF reconstruction is superior to automatic diastolic non-edited reconstructions, especially in arrhythmic patients. RIF theory provides a physiological approach for determining the optimal image reconstruction point in ECG-gated CT angiography. KEY POINTS: Conventional CT coronary angiography suffers from numerous artefacts in patients with irregular rhythms. Coronary computed tomography angiograms (cCTA) were reconstructed with identical cardiac filling (RIF). RIF reconstructions provide improved image quality compared to non-edited standard reconstructions. RIF theory links physiology with cardiac CT.

[Cryoablation - back again?]. / Kryoablation - wieder da?

CLINICAL ISSUE: Primary and secondary liver tumors often limit patient outcome and only a minority of patients are eligible for potential curative surgery. Minimally invasive treatments, such as radiofrequency ablation (RFA), microwave ablation (MWA) and cryoablation are alternative treatment options in a curative and palliative setting. One major limitation of RFA and MWA is the limited size of tumor ablation. Furthermore during the procedure the ablation size can only be roughly estimated using RFA and MWA. STANDARD TREATMENT: RFA is the standard modality of minimally invasive tumor therapy. In comparison cryoablation is rarely used despite its advantages. TREATMENT INNOVATIONS: Argon-helium-based cryoablation systems of the newest generation combine the advantage of small diameter applicators comparable with those of RFA and MWA systems with intrinsic advantages. ACHIEVEMENTS: Cryoablation is a minimally invasive treatment option with advantages, such as virtually unlimited ablation size, real-time visualization using computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound and intrinsic analgesic effects. On the other hand it is not very time-efficient in comparison to MWA. Especially in liver metastases RFA is the preferred treatment option. PRACTICAL RECOMMENDATIONS: Cryoablation is a fascinating treatment option in minimally invasive tumor treatment. It demonstrates good results in hepatocellular carcinoma within the Milan criteria and T1a renal cell carcinoma. Furthermore it is a well-established treatment modality for palliative pain management in bone tumors.

[Process-oriented cost calculation in interventional radiology. A case study]. / Prozessorientierte Kostenrechnung in der Interventionellen Radiologie. Eine Fallstudie.

PURPOSE: Currently used costing methods such as cost centre accounting do not sufficiently reflect the process-based resource utilization in medicine. The goal of this study was to establish a process-oriented cost assessment of percutaneous radiofrequency (RF) ablation of liver and lung metastases. MATERIAL AND METHODS: In each of 15 patients a detailed task analysis of the primary process of hepatic and pulmonary RF ablation was performed. Based on these data a dedicated cost calculation model was developed for each primary process. The costs of each process were computed and compared with the revenue for in-patients according to the German diagnosis-related groups (DRG) system 2010. RESULTS: The RF ablation of liver metastases in patients without relevant comorbidities and a low patient complexity level results in a loss of EUR 588.44, whereas the treatment of patients with a higher complexity level yields an acceptable profit. The treatment of pulmonary metastases is profitable even in cases of additional expenses due to complications. CONCLUSION: Process-oriented costing provides relevant information that is needed for understanding the economic impact of treatment decisions. It is well suited as a starting point for economically driven process optimization and reengineering. Under the terms of the German DRG 2010 system percutaneous RF ablation of lung metastases is economically reasonable, while RF ablation of liver metastases in cases of low patient complexity levels does not cover the costs.

Joint replacement increases radiation exposure to the staff in angiography: A phantom study.

INTRODUCTION: The present study investigates the influence of joint prostheses on the amount of scattered radiation in a simulated angiography set-up. MATERIALS AND METHODS: A clinical angiography system (Artis Zee, Siemens Healthineers, Germany) with a water phantom as a scattering object was used. The scattered radiation of the water phantom was repeatedly measured without prosthesis, with a knee prosthesis and a hip prosthesis made from titanium, aluminum, vanadium, ceramics and polyethylene. For radiation measurement an ionization chamber (ambient dose equivalent rate from 0.1 µSv/h - 100 Sv/h, UMo, Berthold Technologies, Germany) was used. It was positioned on the right side of the phantom simulating an interventional procedure via the right femoral artery. The ionization chamber was positioned at 5 different heights (30, 100, 130, 150 and 165 cm), simulating different body parts of the interventionist. In addition, the amount of scattered radiation in relation to the tube angulation was investigated. RESULTS: Averaged over all angulations at a height of 165 cm, the radiation dose was 2.7 times higher (1935 µSv/h, p < 0.01) when a hip prosthesis was present in comparison to no prosthesis (713 µSv/h). The radiation dose was 3.9 times higher with the integration of a knee prosthesis (2778 µSv/h, p < 0.01) compared to that without prosthesis. The average radiation dose over all angulations and all heights was 1491 µSv/h without prosthesis, 4538 µSv/h with a hip prothesis and 5023 µSv/h with a knee prosthesis respectively. CONCLUSION: This experimental study shows a significant increase in the radiation dose when a joint prosthesis is present in the examination field. Special attention and sufficient radiation protection is therefore necessary for investigations with implanted prostheses.

Safety and feasibility of ultrasound-accelerated catheter-directed thrombolysis in deep vein thrombosis.

OBJECTIVE: One in four patients with primary iliofemoral deep vein thrombosis (DVT) develops post-thrombotic syndrome (PTS) within 1 year despite optimal standard anticoagulant therapy. Removal of thrombus by thrombolytic drugs may prevent PTS. The aim of this study was to assess the short-term safety and efficacy of ultrasound-accelerated catheter-directed thrombolysis (US-accelerated CDT). DESIGN: This was a prospective non-randomised interventional study with US-accelerated CDT for DVT. PATIENTS AND METHODS: Twelve patients with DVT (seven caval-iliofemoropopliteal, three iliofemoropopliteal, one femoropopliteal and one superior caval vein thrombosis) receiving standard anticoagulant and compression therapy, were treated with additional US-accelerated CDT (13 procedures) using the EKOS Endowave(®) system (EKOS Corporation, Bothell, WA, USA) between October 2008 and January 2010. RESULTS: Thrombolysis was successful in 85% (11/13), with complete clot lysis (>90% restored patency) and in one case with partial clot lysis (50-90% restored patency). No pulmonary embolism and one bleeding at the catheter-insertion site were observed. In three patients, underlying lesions were successfully treated with balloon angioplasty and stent insertion. Four patients developed early recurrent thrombosis due to untreated residual venous obstruction. CONCLUSION: US-accelerated CDT is a safe and promising treatment in patients with DVT. Residual venous obstruction should be treated by angioplasty and stent insertion to avoid early re-thrombosis.

[Interventional radiological therapies in lung oncology]. / Interventionell-radiologische Therapien in der pneumologischen Onkologie.

Interventional radiological procedures for the treatment of primary and secondary pulmonary malignancies have become increasingly important. In addition to thermally ablative treatment, selective chemoembolisation by a vascular access allows localised therapy. These treatments are considered to be palliative for patients in a reduced general condition which does not allow systemic chemotherapy. In functionally inoperable patients especially the ablative procedures are potentially curative alternatives to surgery. This article provides an overview of the currently used interventional radiological procedures in lung oncology and assesses their importance. Further studies are needed to show whether interventional radiological procedures, which are promising due to their favourable risk-benefit ratio, may represent an alternative to radiotherapy or be effective in multimodal approaches.

Digital Variance Angiography in Lower-Limb Angiography with Metal Implants.

PURPOSE: The presence of metal implants may reduce angiographic image quality due to automated beam adjustments. Digital variance angiography (DVA) is reported to be superior to digital subtraction angiography (DSA) with increased contrast-to-noise ratio (CNR) and better image quality. The aim of the study was to evaluate whether DVA could counterbalance the image quality impairment of lower-limb angiographies with metal implants. MATERIALS AND METHODS: From November 2019 to January 2020, 85 raw lower-limb iodine contrast angiograms of 12 patients with metal implants were processed retrospectively with DVA analyses. For objective comparison, CNR of DSA and DVA images was calculated and the ratio CNRDVA/CNRDSA was determined. Visual image quality was evaluated in a paired comparison and by a five-grade Likert scale by three experienced radiologists. RESULTS: The CNR was calculated and compared in 1252 regions of interest in 37 image pairs containing metal implants. The median ratio of CNRDVA/CNRDSA was 1.84 with an interquartile range of 1.35-2.32. Paired comparison resulted in 84.5% in favour of DVA with an interrater agreement of 83.2% (Fleiss κ 0.454, p < 0.001). The overall image quality scores for DSA and DVA were 3.64 ± 0.08 and 4.43 ± 0.06, respectively (p < 0.001, Wilcoxon signed-rank test) with consistently higher individual ratings for DVA. CONCLUSION: Our small-sample pilot study shows that DVA provides significantly improved image quality in lower-limb angiography with metal implants, compared to DSA imaging. The improved CNR suggest that this approach could reduce radiation exposure for lower-limb angiography with metal implants. LEVEL OF EVIDENCE: Level 4, case studies.

Scatter radiation reduction with a radiation-absorbing pad in interventional radiology examinations.

PURPOSE: Radiation-absorbing pads are an additional possibility to reduce scattered radiation at its source. The goal of this study is to investigate the efficacy of a new reusable radiation-absorbing pad at its origin in an experimental setup. MATERIAL AND METHODS: All measurements were carried out using a clinical angiography system with a standardized fluoroscopy protocol, different C-arm angulations and an anthropomorphic torso phantom as a scattering body. An ionization chamber was used to measure the radiation exposure at five different heights of a simulated operator during a simulated transfemoral angiography intervention. Measurements were carried out with and without radiation-absorbing pads with lead equivalents of 0.25 and 0.5 mm placed onto the scattering body. For all measurements a mobile acrylic shield and an under-table lead curtain was used. RESULTS: At all operator heights from 100 to 165 cm a significant radiation dose reduction of up to 80.6 % (p < 0.01) using the radiation-absorbing pad was measured, when compared to no radiation-absorbing pad. At the height of 165 cm the radiation-absorbing pad with a lead equivalence of 0.5 mm showed a significant radiation dose reduction (51.4 %, p < 0.01) in comparison to a lead equivalence of 0.25 mm. CONCLUSION: The addition of a radiation-absorbing pad to the standard protection means results in a significant dose reduction for the operator, particularly for upper body parts.

Comparison of different resuscitation methods with regard to injury patterns in cardiac arrest survivors based on computer tomography.

PURPOSE: To ensure that patients survive cardiac arrest, cardiopulmonary resuscitation (CPR) is needed. However, the procedure itself can lead to severe injuries. This study aims to examine both possibilities of resuscitation - mechanical or manual - with regard to their risk of injury. To this end, we compare the injuries patterns in both groups of patients after successful resuscitation based on computer tomography (CT). METHODS: This single-centre retrospective study included 32 patients (female: 21.87 %, male: 78.12 %, Mean age: 60.22 ± 13.93 years) with cardiac arrest followed by successful mechanical CPR, who underwent an early whole-body CT. A control group of 32 patients (female: 21.87 %, male: 78.12 %, mean age: 60.75 ± 13.34 years) that had been resuscitated successfully with manual CPR was matched according to gender and age for a better statistical comparison. Patients with cardiac arrest due to trauma were excluded from the study population. RESULTS: Mechanically resuscitated patients showed significantly more CPR-related injuries than those who were resuscitated manually (100 % vs. 84.37 %; p = 0.02). In particular, dislocated rib fractures (40.47 vs. 23.80 mean rank, p < 0.01), sternal fractures (74.19 % vs. 25 %; p < 0,01), bleeding complications (29.03 % vs. 3.12 %; p = 0.01), pneumothorax (38.71 % vs. 9.37 %; p = 0.01), mediastinal haematomas (58.01 % vs. 25 %, p = 0.01) and liver lacerations (29.03 % vs. 0 %, p = 0.04) were observed significantly more in patients after mechanical CPR compared to those with manual resuscitation. CONCLUSIONS: The guideline-based use of mechanical CPR results in a significant increase of internal and musculoskeletal injuries compared to manual CPR.

Protective Efficacy of Different Ocular Radiation Protection Devices: A Phantom Study.

PURPOSE: The aim of this study was to investigate the efficacy of different designs and types of ocular radiation protection devices depending on simulated varied body heights in a phantom-simulated thoracic intervention. MATERIALS AND METHODS: A clinical angiography system with a standardized fluoroscopy protocol with an anthropomorphic chest phantom as a scattering object and optically stimulated luminescence dosimeters for measuring radiation dose were used. The dosimeters were placed at the position of eyes of an anthropomorphic head phantom simulating the examiner. The head phantom was placed on a height-adjustable stand simulating the height of the examiner from 160 to 200 cm with 10 cm increments. The dose values were then measured with no radiation protection, a weightless-like radiation protection garment, radiation protection glasses and visors. RESULTS: The average dose reduction using radiation protection devices varied between 57.7 and 83.4% (p < 0.05) in comparison with no radiation protection. Some radiation protection glasses and visors showed a significant dose reduction for the eye lenses when the height of the examiner increased. The right eye was partially less protected, especially if the distances between the simulated examiner's head and the scatter object were small. CONCLUSION: All the investigated protection devices showed a significant reduction in radiation exposure to the simulated examiner. For some devices, the radiation dose increased with decreasing distance to the scattering object, especially for the right eye lens.

Carotid plaque analysis: comparison of dual-source computed tomography (CT) findings and histopathological correlation.

PURPOSE: Plaque morphology is an important predictor of stroke risk and may also be a predictor of postoperative outcome after carotid endarterectomy (CEA). Thus, the purpose of our study was to evaluate the findings of preoperative dual-source computed tomography (DSCT) of carotid plaque morphology and correlate these findings with histopathological findings. MATERIAL AND METHODS: Thirty patients undergoing CEA due to neurological events and high-grade carotid artery stenosis were evaluated with DSCT for degree of stenosis following the North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria and for non-invasive plaque morphology prior to CEA. CT protocol was as follows (SOMATOM Definition, Siemens Medical Solutions, Forchheim, Germany): A dual-energy protocol was used with tube A (140 kV, 55 mA) and tube B (80 kV, 230 mA) with 2 x 64 x 0.6-mm collimation, pitch 0.65 and rotation time of 0.33 s. Histopathological work-up was performed on the surgically retrieved tissues. The findings from DSCT and histopathology were compared with respect to image quality and plaque composition (fatty plaque, mixed plaque and calcified plaque), were correlated with histological specimens and classified according to the American Heart Association (AHA) classification of atherosclerotic plaque. Pearson correlation and kappa statistics were performed. RESULTS: The image quality of DSCT was rated as 'excellent' in all the examinations. The mean degree of stenosis was quantified as 82%. The sensitivity of DSCT for the detection of calcification was 100% (standard deviation (SD) 0%, confidence interval (CI): 99-100). While the sensitivity for the detection of mixed plaques was 89% (SD 12%, CI: 79-98), it was 85% (SD 10%, CI: 76-92) for the detection of low-density fatty plaques. The mean degree of agreement was k=0.81. CONCLUSION: DSCT angiography of the carotid arteries is feasible and the evaluation of carotid plaque composition allows non-invasive assessment of different plaque components. This may have an impact on the non-invasive differentiation of vulnerable plaques.

[Multidetector-row spiral computed tomography in chest emergencies]. / MSCT bei thorakalen Notfällen.

With ongoing advances in multidetector-row computed tomography (MDCT) using ECG gating, differentiated examination protocols have become technically feasible. For acute chest pain assessment a strict triage of patients is indispensable, as the radiation dose is approximately 3 times higher for a dedicated protocol compared to a standard chest MDCT. Clinical requests considering pathologies of the pulmonary arteries, the aortic arch and the descending aorta can safely be answered with a standard CT data set. However, for the coronary arteries as well as for the ascending aorta, ECG synchronization of the data set is required. Initial reports regarding MDCT assessment for acute chest pain report a high negative predictive value. With the latest MDCT platforms available, medical preparation is no longer necessary with the exception of sublingual application of nitroglycerine. Dedicated contrast injection protocols, however, are necessary for simultaneous opacification of the pulmonary arteries as well as of the aorta and the coronary arteries. Further prospective studies will have to provide more evidence-based data for acute chest pain assessment with MDCT and will also have to outline the cost-effectiveness of this imaging technique.

[Computer-aided detection of small pulmonary nodules in multidetector spiral computed tomography (MSCT) in children]. / Computerassistierte Detektion (CAD) von kleinen pulmonalen Rundherden in der Mehrdetektor-Spiral-Computertomografie (MDCT) bei Kindern.

PURPOSE: Retrospective evaluation of computer-aided detection software (CAD) for automated detection (LungCAD, Siemens Medical solutions, Forchheim, Germany) and volumetry (LungCARE) of pulmonary nodules in dose-reduced pediatric MDCT. MATERIALS AND METHODS: 30 scans of 24 children (10.4+/-5.9 years, 13 girls, 11 boys, 39.7+/-29.3 kg body weight) were performed on a 16-MDCT for tumor staging (n=18), inflammation (n=9), other indications (n=3). Tube voltage 120 kVp and effective mAs were adapted to body weight. Slice thickness 2 mm, increment 1 mm. A pediatric radiologist (U1), a CAD expert (U2) and an inexperienced radiologist (U3) independently analyzed the lung window images without and with the CAD as a second reader. In a consensus decision U 1 and U 2 were the reference standard. RESULTS: Five examinations had to be excluded from the study due to other underlying lung disease. A total of 24 pulmonary nodules were found in all data sets with a minimal diameter of 0.35 mm to 3.81 mm (mean 1.7+/-0.85 mm). The sensitivities were as follows: U1 95.8% and 100% with CAD; U2 91.7% U3 66.7%. U2 and U3 did not detect further nodules with CAD. The sensitivity of CAD alone was 41.7 % with 0.32 false-positive findings per examination. Interobserver agreement between U1 / U2 regarding nodule detection with CAD was good (k=0.6500) and without CAD very good (k=0.8727). For the rest (U1 /U3; U2 / U3 with and without CAD), it was weak (k=0.0667-0.1884). Depending on the measured value (axial measurement, volume), there is a significant correlation (p=0.0026-0.0432) between nodule size and CAD detection. Undetected pulmonary nodules (mean 1.35 mm; range 0.35-2.61 mm) were smaller than the detected ones (mean 2.19 mm; range 1.35-3.81 mm). No significant correlation was found between CAD findings and patient age (p=0.9263) and body weight (p=0.9271) as well as nodule location (subpleural, intraparenchymal; p=1.0) and noise/SNR. CONCLUSION: In our study with 2 mm slice thickness and very small lesion sizes, the analyzed CAD algorithm for detection and volumetry of pulmonary nodules has limited application in pediatric dose-reduced 16-MDCTs. Determination of lesion size is possible even in the case of false-negatives.