Lowering radiation exposure in CT angiography using automated tube potential selection and optimized iodine delivery rate.

Objective: The purpose of this study was to determine the effectiveness of a radiation dose reduction strategy for CT angiography by the combination of higher iodine delivery rate and automated tube potential selection with adjusted reference values for tube current-exposure time product, as well as to measure the impact of this approach on image quality.

Subjects And Methods: One hundred consecutive patients underwent high-pitch CT angiography of the thorax and abdomen using either 90 mL of iomeprol 300 (n = 44, protocol A) or 90 mL of iomeprol 400 (n = 56, protocol B) at the same flow rate. Automated tube potential selection was used with reference tube current-time products of 330 mAs and 250 mAs for protocols A and B, respectively.

Evaluation of a handheld creatinine measurement device for real-time determination of serum creatinine in radiology departments.

Aim: To assess the feasibility/accuracy of a commercial handheld device in the context of increased demand for point-of-care serum creatinine (SCr) determination.

Methods: In this institutional review board-approved, prospective study, 401 patients referred for contrast-enhanced computed tomography were included at two centres. Capillary (c)SCr was determined using two devices A+B and venous (v)SCr was determined in the centre's laboratory.

Time-resolved CT angiography for the detection and classification of endoleaks.

Purpose: To assess the feasibility and diagnostic performance of time-resolved computed tomographic (CT) angiography in the detection and classification of endoleaks after endovascular aortic aneurysm repair (EVAR) in high-risk patients.

Materials And Methods: The study was approved by our ethics committee. Written informed consent was obtained from all participating patients.

Direct costs and cost-effectiveness of dual-source computed tomography and invasive coronary angiography in patients with an intermediate pretest likelihood for coronary artery disease.

Aims: The study aims to determine the direct costs and comparative cost-effectiveness of latest-generation dual-source computed tomography (DSCT) and invasive coronary angiography for diagnosing coronary artery disease (CAD) in patients suspected of having this disease.

Methods: The study was based on a previously elaborated cohort with an intermediate pretest likelihood for CAD and on complementary clinical data. Cost calculations were based on a detailed analysis of direct costs, and generally accepted accounting principles were applied.

Meta-analysis and systematic review of the long-term predictive value of assessment of coronary atherosclerosis by contrast-enhanced coronary computed tomography angiography.

Objectives: We conducted a systematic review and meta-analysis to determine the predictive value of findings of coronary computed tomography angiography for incident cardiovascular events.

Background: Initial studies indicate a prognostic value of the technique; however, the level of evidence as well as exact independent risk estimates remain unclear.

Methods: We searched PubMed, EMBASE, and the Cochrane Library through January 2010 for studies that followed up ≥ 100 subjects for ≥ 1 year and reported at ≥ 1 hazard ratio (HR) of interest.

Metal artifact reduction by dual energy computed tomography using monoenergetic extrapolation.

Objective: The aim of the study was to assess the performance and diagnostic value of a dual energy CT approach to reduce metal artefacts in subjects with metallic implants.

Methods: 31 patients were examined in the area of their metallic implants using a dual energy CT protocol (filtered 140 kVp and 100 kVp spectrum, tube current relation: 3:1). Specific post-processing was applied to generate energies of standard 120 and 140 kVp spectra as well as a filtered 140 kVp spectrum with mean photon energies of 64, 69 and 88 keV, respectively, and an optimized hard spectrum of 95-150 keV.

Diagnostic image quality of a comprehensive high-pitch dual-spiral cardiothoracic CT protocol in patients with undifferentiated acute chest pain.

Objective: To evaluate diagnostic image quality of high-pitch dual source comprehensive cardiothoracic CT protocol in patients presenting with acute undifferentiated chest pain.

Materials And Methods: Consecutive symptomatic subjects (n=51) with undifferentiated acute chest pain underwent ECG-synchronized high-pitch dual-spiral chest CT angiography (Definition Flash, Siemens Medical Solutions, 2 × 100 kVp or 2 × 120 kV if BMI>30, collimation: 128 × 0.6mm, pitch: 3.

Diagnostic value of time-resolved CT angiography for the lower leg.

Objective: The aim of this study was to test the feasibility of time-resolved computed tomography angiography (TR-CTA) for use in the lower leg.

Methods: Fifty-nine patients with suspected peripheral arterial occlusive disease were examined with a standard CTA (S-CTA) of the lower run-off and with an additional TR-CTA of the calves (12 phases; 2.5 s/phase, 80 kV, 120 mAs, volume of contrast medium 50 mL, flow rate 5.

Pulmonary ventilation and perfusion imaging with dual-energy CT.

Objective: To evaluate the feasibility of dual-energy CT (DECT) ventilation imaging in combination with DE perfusion mapping for a comprehensive assessment of ventilation, perfusion, morphology and structure of the pulmonary parenchyma.

Methods: Two dual-energy CT acquisitions for xenon-enhanced ventilation and iodine-enhanced perfusion mapping were performed in patients under artificial respiration. Parenchymal xenon and iodine distribution were mapped and correlated with structural or vascular abnormalities.

Comparison of time-resolved CT-angiography, contrast-enhanced ultrasound and digital subtraction angiography in a patient with a small type II endoleak after endovascular aneurysm repair.

We report discordant imaging findings of a small persistent type II endoleak in a 72-year-old man who had undergone endovascular aneurysm repair (EVAR) of an abdominal aortic aneurysm. Although the aneurysm was growing in size digital subtraction angiography could not detect an endoleak, but time-resolved CT-angiography and contrast enhanced ultrasound did detect a small type II endoleak.

Single-phase dual-energy CT allows for characterization of renal masses as benign or malignant.

Purpose: To evaluate the diagnostic accuracy of dual-energy CT (DECT) in renal mass characterization using a single-phase acquisition.

Materials And Methods: A total of 202 patients (148 males, 54 females; 63 +/- 13 years) with ultrasound-based suspicion of a renal mass underwent unenhanced single energy and nephrographic phase DECT on a dual source scanner (Siemens Somatom Definition Dual Source, n = 174; Somatom Definition Flash, n = 28). Scan parameters for DECT were: tube potential, 80/100 and 100/Sn140 kVp; exposure, 404/300 and 96/232 effective mAs; collimation, 14 x 1.

Time-resolved computed tomography imaging of the aorta: a feasibility study.

Purpose: The aim of this study was to test the feasibility and the additional value of time-resolved computed tomography angiography (CTA) of the aorta, using multiple low-dose phases.

Materials And Methods: Twenty-two consecutive patients underwent a time-resolved CTA protocol (TR-CTA) of the aorta, either for follow-up of endovascular aneurysm repair (EVAR) or aortic dissection, using a CT scanner with the possibility of bidirectional table movements for dynamic CT imaging (Siemens Definition AS+; 12 phases, temporal resolution 2.5 s/scan, 80 kVp, 120 mAs/rot, scan range 27 cm, 60 mL; Imeron 400, flow 5.

Advantages of extended brain perfusion computed tomography: 9.6 cm coverage with time resolved computed tomography-angiography in comparison to standard stroke-computed tomography.

Objective: Recent technical developments have led to an extension of perfusion computed tomography (PCT) scan range to cover nearly the entire brain and to reconstruct time resolved (4d) CT-angiography (CTA) datasets from the PCT data. The purpose of this study was to compare the results of simulated standard PCT and extended PCT with 4d-CTA.

Materials And Methods: Extended multimodal stroke CT (unenhanced cranial CT, CTA, and PCT) was acquired in 72 patients.

Dual energy CT of the chest: how about the dose?

Objective: New generation Dual Source computed tomography (CT) scanners offer different x-ray spectra for Dual Energy imaging. Yet, an objective, manufacturer independent verification of the dose required for the different spectral combinations is lacking. The aim of this study was to assess dose and image noise of 2 different Dual Energy CT settings with reference to a standard chest scan and to compare image noise and contrast to noise ratios (CNR).

Dynamic myocardial stress perfusion imaging using fast dual-source CT with alternating table positions: initial experience.

Objective: To detail the principles of using model-based determination of regional myocardial blood flow (MBF) by computed tomography (CT) and demonstrate its in vivo applicability.

Methods: Dual-source CT was performed with a dynamic protocol comprising acquisition with alternating table positions in ECG-triggered end-systolic timing every second for 30 s. The results of two reconstructions were merged into one final image stack (coverage 73 mm), with low spatial frequency components from a 360 degrees reconstruction and high spatial frequency components from a dual-source cardiac partial image reconstruction.

Image quality of virtual noncontrast images derived from dual-energy CT angiography after endovascular aneurysm repair.

Purpose: To compare true and "virtual" noncontrast images derived from dual-energy CT examinations in patients after endovascular repair of aortic aneurysms.

Materials And Methods: Seventy dual-energy CT examinations were performed on a dual-source CT scanner with a single-energy noncontrast scan and a dual-energy acquisition in venous phase. True and virtual noncontrast images were compared regarding image quality, calcifications in true noncontrast images, subtraction of calcification in virtual noncontrast images, and acceptance levels by two radiologists.

Systolic acquisition of coronary dual-source computed tomography angiography: feasibility in an unselected patient population.

Objective: To determine the practicability and potential dose saving of an imaging algorithm incorporating a pulsing scheme applying systolic data acquisition at heart rates >75 beats per minute (bpm).

Methods: Patients clinically referred for coronary computed tomography angiography (CTA) underwent cardiac CTA using either a diastolic pulsing window (30-70%) or a narrow systolic pulsing window (150 ms at 300 ms). Independent investigators retrospectively determined image quality (1, excellent, to 5, unreadable) and derived effective radiation exposure.

Saving dose in triple-rule-out computed tomography examination using a high-pitch dual spiral technique.

Objective: High radiation doses remain a drawback of current triple-rule-out computed tomography (CT) protocols. With dual source CT, a new high-pitch dual spiral technique offers the possibility to acquire an Electrocardiography (ECG)-gated-synchronized dataset of the whole chest in less than 1 second. The aim of this study was to compare the dose of such a protocol to a standard, nongated chest scan and to a conventional, retrospectively ECG-gated triple-rule-out protocol.

64-Slice CT angiography of the abdominal aorta and abdominal arteries: comparison of the diagnostic efficacy of iobitridol 350 mgI/ml versus iomeprol 400 mgI/ml in a prospective, randomised, double-blind multi-centre trial.

Purpose: The purpose of this study was to assess the influence of iodine concentration on diagnostic efficacy in multi-detector-row computed tomography (MDCT) angiography of the abdominal aorta and abdominal arteries.

Methods: IRB approval and informed consent were obtained. In this double-blind trial, patients were randomised to undergo MDCT angiography of the abdominal arteries during administration of iobitridol (350 mgI/ml) or iomeprol (400 mgI/ml).

Evaluation of coronary atherosclerotic plaques.

In many patients, unheralded myocardial infarction associated with a mortality of approximately 20% is the first manifestation of coronary artery disease. Approximately 40% of the population is considered to have a moderate midterm risk of 10% to 20%. Any of the stratification schemes suffers from a lack of accuracy to correctly determine the risk, and uncertainty exists regarding how to treat individuals who have been identified to be at intermediate risk.

Perfusion patterns of metastatic gastrointestinal stromal tumor lesions under specific molecular therapy.

Rationale And Objective: The aim of this pilot study was the evaluation of CT perfusion patterns in metastatic GIST lesions under specific molecular therapy with sunitinib or imatinib both in responders and non-responders.

Patients And Methods: 24 patients with metastatic GIST under tyrosine kinase inhibition were retrospectively evaluated. A total of 46 perfusion and venous phase CT scans were acquired.

Dual-energy CT for the assessment of contrast material distribution in the pulmonary parenchyma.

Objective: The purpose of this study was to assess the feasibility and diagnostic value of dual-energy CT iodine mapping at pulmonary CT angiography.

Subjects And Methods: Ninety-three patients underwent CT angiography with the dual-energy technique on a dual-source CT scanner. Postprocessing was used to map iodine in the lung parenchyma on the basis of its spectral behavior, and image quality was assessed by two readers.

Dual-energy CT in patients suspected of having renal masses: can virtual nonenhanced images replace true nonenhanced images?

Purpose: To qualitatively and quantitatively compare virtual nonenhanced (VNE) data sets derived from dual-energy (DE) computed tomography (CT) with true nonenhanced (TNE) data sets in the same patients and to calculate potential radiation dose reductions for a dual-phase renal multidetector CT compared with a standard triple-phase protocol.

Materials And Methods: This prospective study was approved by the institutional review board; all patients provided written informed consent. Seventy one men (age range, 30-88 years) and 39 women (age range, 22-87 years) underwent preoperative DE CT that included unenhanced, DE nephrographic, and delayed phases.

Adequate image quality with reduced radiation dose in prospectively triggered coronary CTA compared with retrospective techniques.

The goal of our study was to compare a prospective triggering (PT) CT technique with retrospectively gated (RG) CT techniques in coronary computed tomographic angiograms (CCTA) with respect to image quality and radiation dose. Sixty consecutive patients were enrolled. CCTAs using the RG technique were obtained with a dual-source 64-slice CT system in 40 patients, using ECG-triggered tube current modulation, with either a broad pulsing window at 30-80% of the RR interval (group RGb, 20 patients, heart rate > 70 bpm) or a small pulsing window at 70% (group RGs, 20 patients, heart rate < 70 bpm).

The value of dual-energy bone removal in maximum intensity projections of lower extremity computed tomography angiography.

Objective: Dual-energy computed tomography (CT) makes it possible to remove bones and intraluminal plaques from angiography datasets on the basis of spectral differentiation separating iodine from calcium. The objective of this study was to evaluate the feasibility and efficiency of this technique by comparing maximum intensity projections (MIP) created with different bone removal techniques: (a) dual-energy bone removal (DEBR); (b) purely software-based bone removal without manual corrections (SBBR - MC); and (c) manually corrected software-based bone removal (SBBR + MC). A further aim was to evaluate the dual-energy-based plaque removal tool.