Automated Attenuation Based Tube Potential Selection of the Lower Extremity Runoff: A Comparison to Fixed Kilovolt with Automated Tube Current Modulation.

PURPOSE: The aim of this study was to evaluate the impact of automated attenuation-based tube potential selection (ATPS) on image quality and radiation dose exposure parameters at a computed tomography angiography (CTA) lower-extremity runoff. MATERIALS AND METHODS: Two hundred forty patients (156 men, 84 women) underwent CTA examinations of the lower-extremity runoff on a second-generation dual-source computed tomography system: 120 patients at a fixed tube potential of 120 kV and a tube current of 180 reference mAs, another 120 patients using automated ATPS. Volume computed tomography dose index (CTDIvol), dose-length-product (DLP), body diameters, noise, signal-to-noise ratio, and subjective image quality were compared. RESULTS: In the ATPS group, 80 kV was automatically selected in 102 patients, 100 kV in 15 patients, and 120 kV in 3 patients; 140 kV was not chosen in any of the cases. The median CTDIvol of 4.81 mGy (2.2-10.6 mGy) and DLP of 568 mGy⋅cm (203-1324 mGy⋅cm) in the ATPS group were significantly lower compared with the CTDIvol of 8.1 mGy (4.4-14.4 mGy) and DLP of 1027.5 mGy⋅cm (509-1806 mGy⋅cm) in the fixed 120-kV group (P < 0.01). Image quality was comparable (P > 0.05). CONCLUSION: Automated ATPS allows for significant dose savings in lower-extremity runoff CTA, whereas image quality remains constant at a high level.

Anatomy Revisited: Hemodialysis Catheter Malposition in the Left Ascending Lumbar Vein.

In selected cases, cuffed tunneled catheters via the iliac vein are implanted as a last resort access for hemodialysis. To monitor the correct position, sonography of the inferior vena cava (IVC) is sufficient in most cases. Position control using an X-ray of the abdomen is not routinely recommended when femoral catheters are implanted. In this report, we describe the case of a 59-year-old patient on chronic hemodialysis due to granulomatosis with polyangiitis and complex shunt history with multiple shunt occlusions and revisions. The implantation of an iliac-cuffed tunneled catheter led to complications because the catheter was malpositioned into the left ascending lumbar vein (ALV). It is important to be aware of potential incorrect positioning of dialysis catheters into the ALV. Due to the anatomical relation to the IVC, this happens more frequently on the left side than on the right side. In case of doubt, the correct placement of large-bore catheters via iliac access route should be verified by means of appropriate imaging before hemodialysis is performed.

Single-energy pediatric chest computed tomography with spectral filtration at 100 kVp: effects on radiation parameters and image quality.

BACKGROUND: Most of the applied radiation dose at CT is in the lower photon energy range, which is of limited diagnostic importance. OBJECTIVE: To investigate image quality and effects on radiation parameters of 100-kVp spectral filtration single-energy chest CT using a tin-filter at third-generation dual-source CT in comparison to standard 100-kVp chest CT. MATERIALS AND METHODS: Thirty-three children referred for a non-contrast chest CT performed on a third-generation dual-source CT scanner were examined at 100 kVp with a dedicated tin filter with a tube current-time product resulting in standard protocol dose. We compared resulting images with images from children examined using standard single-source chest CT at 100 kVp. We assessed objective and subjective image quality and compared radiation dose parameters. RESULTS: Radiation dose was comparable for children 5 years old and younger, and it was moderately decreased for older children when using spectral filtration (P=0.006). Effective tube current increased significantly (P=0.0001) with spectral filtration, up to a factor of 10. Signal-to-noise ratio and image noise were similar for both examination techniques (P≥0.06). Subjective image quality showed no significant differences (P≥0.2). CONCLUSION: Using 100-kVp spectral filtration chest CT in children by means of a tube-based tin-filter on a third-generation dual-source CT scanner increases effective tube current up to a factor of 10 to provide similar image quality at equivalent dose compared to standard single-source CT without spectral filtration.

Dual-Energy CT-based Display of Bone Marrow Edema in Osteoporotic Vertebral Compression Fractures: Impact on Diagnostic Accuracy of Radiologists with Varying Levels of Experience in Correlation to MR Imaging.

Purpose To evaluate whether a dual-energy (DE) computed tomographic (CT) virtual noncalcium technique can improve the detection rate of acute thoracolumbar vertebral compression fractures in patients with osteoporosis compared with that at magnetic resonance (MR) imaging depending on the level of experience of the reading radiologist. Materials and Methods This retrospective study was approved by the institutional ethics committee. Informed consent was obtained from all patients. Forty-nine patients with osteoporosis who were suspected of having acute vertebral fracture underwent DE CT and MR imaging. Conventional linear-blended CT scans and corresponding virtual noncalcium reconstructions were obtained. Five radiologists with varying levels of experience evaluated gray-scale CT scans for the presence of fractures and their suspected age. Then, virtual noncalcium images were evaluated to detect bone marrow edema. Findings were compared with those from MR imaging (the standard of reference). Sensitivity and specificity analyses for diagnostic performance and matched pair analyses were performed on vertebral fracture and patient levels. Results Sixty-two fractures were classified as fresh and 52 as old at MR imaging. The diagnostic performance of all readers in the detection of fresh fractures improved with the addition of virtual noncalcium reconstructions compared with that with conventional CT alone. Although the diagnostic accuracy of the least experienced reader with virtual noncalcium CT (accuracy with CT alone, 61%; accuracy with virtual noncalcium technique, 83%) was within the range of that of the most experienced reader with CT alone, the latter improved his accuracy with the noncalcium technique (from 81% to 95%), coming close to that with MR imaging. The number of vertebrae rated as unclear decreased by 59%-90% or from 15-53 to 2-13 in absolute numbers across readers. The number of patients potentially referred to MR imaging decreased by 36%-87% (from 11-23 to 2-10 patients). Considering the gain in true decisions with the virtual noncalcium technique on a patient level, between 12 (most experienced reader) and 17 (least experienced reader) MR examinations could have been avoided. Conclusion The DE CT-based virtual noncalcium technique may enable depiction of bone marrow edema in thoracolumbar vertebral compression fractures in patients with osteoporosis, with good accordance with MR imaging when images are read by experienced radiologists. Although less experienced readers improved their diagnostic performance to some degree, the experienced reader's diagnostic performance approached that with MR imaging. (©) RSNA, 2016.

Advanced image-based virtual monoenergetic dual-energy CT angiography of the abdomen: optimization of kiloelectron volt settings to improve image contrast.

OBJECTIVES: To compare quantitative image quality parameters in abdominal dual-energy computed tomography angiography (DE-CTA) using an advanced image-based (Mono+) reconstruction algorithm for virtual monoenergetic imaging and standard DE-CTA. METHODS: Fifty-five patients (36 men; mean age, 64.2 ± 12.7 years) who underwent abdominal DE-CTA were retrospectively included. Mono + images were reconstructed at 40, 50, 60, 70, 80, 90 and 100 keV levels and as standard linearly blended M_0.6 images (60 % 100 kV, 40 % 140 kV). The contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) of the common hepatic (CHA), splenic (SA), superior mesenteric (SMA) and left renal arteries (LRA) were objectively measured. RESULTS: Mono+ DE-CTA series showed a statistically superior CNR for 40, 50, 60, 70 and 80 keV (P < 0.031) compared to M_0.6 images for all investigated arteries except SMA at 80 keV (P = 0.08). CNR at 40 keV revealed a mean relative increase of 287.7 % compared to linearly blended images among all assessed arteries (P < 0.001). SNR of Mono+ images was consistently significantly higher at 40, 50, 60 and 70 keV compared to M_0.6 for CHA and SA (P < 0.009). CONCLUSIONS: Compared to linearly blended images, Mono+ reconstructions at low keV levels of abdominal DE-CTA datasets significantly improve quantitative image quality. KEY POINTS: • Mono+ combines increased attenuation with reduced image noise compared to standard DE-CTA. • Mono+ shows superior contrast-to-noise ratios at low keV compared to linearly-blended images. • Contrast-to-noise ratio in monoenergetic DE-CTA peaks at 40 keV. • Mono+ reconstructions significantly improve quantitative image quality at low keV levels.

Dual-Energy Computed Tomography Virtual Monoenergetic Imaging of Lung Cancer: Assessment of Optimal Energy Levels.

OBJECTIVE: The aim of the study was to evaluate objective and subjective image qualities of virtual monoenergetic imaging (VMI) in dual-source dual-energy computed tomography (DECT) and optimal kiloelectron-volt (keV) levels for lung cancer. METHODS: Fifty-nine lung cancer patients underwent chest DECT. Images were reconstructed as VMI series at energy levels of 40, 60, 80, and 100 keV and standard linear blending (M_0.3) for comparison. Objective and subjective image qualities were assessed. RESULTS: Lesion contrast peaked in 40-keV VMI reconstructions (2.5 ± 2.9) and 60 keV (1.9 ± 3.0), which was superior to M_0.3 (0.5 ± 2.7) for both comparisons (P < 0.001). Compared with M_0.3, subjective ratings were highest for 60-keV VMI series regarding general image quality (4.48 vs 4.52; P = 0.74) and increased for lesion demarcation (4.07 vs 4.84; P < 0.001), superior to all other VMI series (P < 0.001). Image sharpness was similar between both series. Image noise was rated superior in the 80-keV and M_0.3 series, followed by 60 keV. CONCLUSIONS: Virtual monoenergetic imaging reconstructions at 60-keV provided the best combination of subjective and objective image qualities in DECT of lung cancer.

Improved visual delineation of the intimal flap in Stanford type A and B dissections at 3rd generation dual-source high-pitch CT angiography.

OBJECTIVE: Evaluation of the intimal flap visibility comparing 2nd and 3rd generation dual-source high-pitch CT. METHODS: Twenty-five consecutive patients with aortic dissection underwent CT angiography on a second and third generation dual-source CT scanner using prospective ECG-gated high-pitch dual-source CT acquisition mode. Contrast material, saline flush and flow rate were kept equal for optimum comparability. The visibility of the intimal flap as well as the delineation of the different vascular structures was evaluated. RESULTS: In 3rd generation dual-source high-pitch CT we could show a significant improvement of intimal flap visibility in aortic dissection. Especially, the far end of the dissection membrane could be better evaluated in 3rd generation high-pitch CT, reaching statistical significance (P < 0.01). CONCLUSION: 3rd Generation high-pitch CT angiography shows a better delineation of the aortic intimal flap in a small patient cohort, especially in the far ends of the dissection membrane. This might be due to higher tube power in this CT generation. However, to generalise these findings larger trials are needed.

Assessment of an Advanced Monoenergetic Reconstruction Technique in Dual-Energy Computed Tomography of Head and Neck Cancer.

OBJECTIVES: To define optimal keV settings for advanced monoenergetic (Mono+) dual-energy computed tomography (DECT) in patients with head and neck squamous cell carcinoma (SCC). METHODS: DECT data of 44 patients (34 men, mean age 55.5 ± 16.0 years) with histopathologically confirmed SCC were reconstructed as 40, 55, 70 keV Mono + and M_0.3 (30 % 80 kV) linearly blended series. Attenuation of tumour, sternocleidomastoid muscle, internal jugular vein, submandibular gland, and noise were measured. Three radiologists with >3 years of experience subjectively assessed image quality, lesion delineation, image sharpness, and noise. RESULTS: The highest lesion attenuation was shown for 40 keV series (248.1 ± 94.1 HU), followed by 55 keV (150.2 ± 55.5 HU; P = 0.001). Contrast-to-noise ratio (CNR) at 40 keV (19.09 ± 13.84) was significantly superior to all other reconstructions (55 keV, 10.25 ± 9.11; 70 keV, 7.68 ± 6.31; M_0.3, 5.49 ± 3.28; all P < 0.005). Subjective image quality was highest for 55 keV images (4.53; κ = 0.38, P = 0.003), followed by 40 keV (4.14; κ = 0.43, P < 0.001) and 70 keV reconstructions (4.06; κ = 0.32, P = 0.005), all superior (P < 0.004) to linear blending M_0.3 (3.81; κ = 0.280, P = 0.056). CONCLUSIONS: Mono + DECT at low keV levels significantly improves CNR and subjective image quality in patients with head and neck SCC, as tumour CNR peaks at 40 keV, and 55 keV images are preferred by observers. KEY POINTS: • Mono + DECT combines increased contrast with reduced image noise, unlike linearly blended images. • Mono + DECT imaging allows for superior CNR and subjective image quality. • Head and neck tumour contrast-to-noise ratio peaks at 40 keV. • 55 keV images are preferred over all other series by observers.

Objective and subjective image quality of primary and recurrent squamous cell carcinoma on head and neck low-tube-voltage 80-kVp computed tomography.

INTRODUCTION: To investigate low-tube-voltage 80-kVp computed tomography (CT) of head and neck primary and recurrent squamous cell carcinoma (SCC) regarding objective and subjective image quality. METHODS: We retrospectively evaluated 65 patients (47 male, 18 female; mean age: 62.1 years) who underwent head and neck dual-energy CT (DECT) due to biopsy-proven primary (n = 50) or recurrent (n = 15) SCC. Eighty peak kilovoltage and standard blended 120-kVp images were compared. Attenuation and noise of malignancy and various soft tissue structures were measured. Tumor signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Subjective image quality was rated by three reviewers using 5-point grading scales regarding overall image quality, lesion delineation, image sharpness, and image noise. Radiation dose was assessed as CT dose index volume (CTDIvol). Interobserver agreement was calculated using intraclass correlation coefficient (ICC). RESULTS: Mean tumor attenuation (153.8 Hounsfield unit (HU) vs. 97.1 HU), SNR (10.7 vs. 8.3), CNR (8.1 vs. 4.8), and subjective tumor delineation (score, 4.46 vs. 4.13) were significantly increased (all P < 0.001) with 80-kVp acquisition compared to standard blended 120-kVp images. Noise of all measured structures was increased in 80-kVp acquisition (P < 0.001). Overall interobserver agreement was good (ICC, 0.86; 95 % confidence intervals: 0.82-0.89). CTDIvol was reduced by 48.7 % with 80-kVp acquisition compared to standard DECT (4.85 ± 0.51 vs. 9.94 ± 0.81 mGy cm, P < 0.001). CONCLUSIONS: Head and neck CT with low-tube-voltage 80-kVp acquisition provides increased tumor delineation, SNR, and CNR for CT imaging of primary and recurrent SCC compared to standard 120-kVp acquisition with an accompanying significant reduction of radiation exposure.

First Clinical Evaluation of High-Pitch Dual-Source Computed Tomographic Angiography Comparing Automated Tube Potential Selection With Automated Tube Current Modulation.

OBJECTIVE: To investigate and compare the use of automated tube potential selection (ATPS) with automated tube current modulation (ATCM) in high-pitch dual-source computed tomographic angiography (CTA) for imaging the whole aorta without electrocardiogram synchronization. METHODS: Two groups of 60 patients underwent CTA on a dual-source computed tomographic device in high-pitch mode: ATCM (with 100-kV fixed tube potential) was used in group 1 and ATPS (with the same image quality options) in group 2. For the evaluation of radiation exposure, CT dose index and dose-length product were analyzed. Contrast and image quality were assessed by 2 independent observers. RESULTS: The ATPS group received a higher radiation dose than the ATCM group (P < 0.001) because in 80% of patients, the software switched to use of a 120-kV tube potential. In all cases, images of the aorta were of sufficient quality. CONCLUSIONS: High-pitch dual-source CTA of the aorta using ATPS is feasible in clinical routine, but is associated with higher radiation exposure than the ATCM protocol. This finding contradicts previously evaluations of ATPS based on single-source techniques.

Synaptic cell adhesion molecule SynCAM 1 is a target for polysialylation in postnatal mouse brain.

Among the large set of cell surface glycan structures, the carbohydrate polymer polysialic acid (polySia) plays an important role in vertebrate brain development and synaptic plasticity. The main carrier of polySia in the nervous system is the neural cell adhesion molecule NCAM. As polySia with chain lengths of more than 40 sialic acid residues was still observed in brain of newborn Ncam(-/-) mice, we performed a glycoproteomics approach to identify the underlying protein scaffolds. Affinity purification of polysialylated molecules from Ncam(-/-) brain followed by peptide mass fingerprinting led to the identification of the synaptic cell adhesion molecule SynCAM 1 as a so far unknown polySia carrier. SynCAM 1 belongs to the Ig superfamily and is a powerful inducer of synapse formation. Importantly, the appearance of polysialylated SynCAM 1 was not restricted to the Ncam(-/-) background but was found to the same extent in perinatal brain of WT mice. PolySia was located on N-glycans of the first Ig domain, which is known to be involved in homo- and heterophilic SynCAM 1 interactions. Both polysialyltransferases, ST8SiaII and ST8SiaIV, were able to polysialylate SynCAM 1 in vitro, and polysialylation of SynCAM 1 completely abolished homophilic binding. Analysis of serial sections of perinatal Ncam(-/-) brain revealed that polySia-SynCAM 1 is expressed exclusively by NG2 cells, a multifunctional glia population that can receive glutamatergic input via unique neuron-NG2 cell synapses. Our findings sug-gest that polySia may act as a dynamic modulator of SynCAM 1 functions during integration of NG2 cells into neural networks.

High-pitch Dual-source CT Angiography before TAVI - the Value of ECG Gating.

PURPOSE: To investigate image quality, and radiation dose between ECG-gated singlesource and dual-source CT Angiography (CTA) protocols for planning of Trans-catheter Aortic Valve Implantation (TAVI) with a reference non ECG-gated single-source protocol. METHODS: A total of 120 patients were included in four groups: Non ECG-gated single-source (SS), ECG-gated single-source (SSECG), ECG-gated dual-source high-pitch (DSECG), or non-ECG-gated dual-source high-pitch mode (DS). Qualitative image quality of the aortic annulus, aortic valve, and coronary ostia as well as presence of motion or stair-step artefacts of the thoracic aorta were independently assessed by two readers. Quantitative image quality was assessed to calculate contrast to noise ratio. RESULTS: Subjective and objective scoring of motion artefacts was significantly reduced in SSECG, DSECG and DS (p= 0.010). The imaging length was comparable between groups. Aortic annulus, aortic valve, and coronary ostia were reliably evaluable in all patients with SSECG, DSECG and DS protocols. CONCLUSION: High-pitch, dual-source CT angiography of the whole aorta with or without ECG gating is a dose-efficient and time-saving examination strategy before TAVI. However acquisition timing within the cardiac cycle needs to be taken into account.

Dual-Energy Computed Tomography-Based Display of Bone Marrow Edema in Incidental Vertebral Compression Fractures: Diagnostic Accuracy and Characterization in Oncological Patients Undergoing Routine Staging Computed Tomography.

PURPOSE: The aim of this study was to evaluate the diagnostic performance of virtual noncalcium (VNCa) dual-energy computed tomography (DECT) reconstructions enabling visualization of bone marrow edema for characterization of incidental thoracolumbar compression fractures in routine thoracoabdominal staging computed tomography (CT). MATERIALS AND METHODS: We retrospectively analyzed 51 oncological patients without suspected fracture or indicative complaints presenting at least 1 thoracolumbar compression fracture on routine thoracoabdominal staging DECT who had been examined between October 2015 and June 2017 using third-generation dual-source CT, had a previous CT within 3 months before, and also had undergone additional magnetic resonance imaging within 14 days, which served as the standard of reference. Three independent and blinded radiologists initially evaluated all vertebrae on conventional grayscale DECT series; after at least 8 weeks, observers reevaluated all cases using grayscale and color-coded VNCa DECT images. The age of each fracture was determined as either acute, chronic, or inconclusive. Specificity, sensitivity, and intraobserver and interobserver agreements were calculated taking into account clustering. RESULTS: A total of 98 vertebral compression fractures were detected in 51 patients (20 women, 31 men; median of 1 fracture per patient). The reference standard defined 45 as acute and 53 as chronic. For identification of only acute fractures (cutoff 1), the combination of grayscale and VNCa image series showed a higher sensitivity (91% vs 47%; P < 0.001) but equal specificity (both 100%) compared with analysis of grayscale images alone. When defining a positive finding as a fracture considered either acute or inconclusive (cutoff 2), combined analysis of grayscale and VNCa images showed similar sensitivity (96% vs 93%; P = 0.28) but significantly higher specificity (96% vs 75%; P < 0.001) compared with evaluation of grayscale images alone. Area under the curve analysis for detection of vertebral compression fractures showed superior results for reading of grayscale and VNCa image series (0.98) compared with analysis of grayscale images alone (0.89; P < 0.001). CONCLUSION: Dual-energy CT-derived color-coded VNCa reconstructions substantially improve the characterization of incidental thoracolumbar compression fractures seen on routine thoracoabdominal staging DECT by allowing for visualization of bone marrow edema.

Low-dose CT pulmonary angiography on a 15-year-old CT scanner: a feasibility study.

BACKGROUND: Computed tomography (CT) low-dose (LD) imaging is used to lower radiation exposure, especially in vascular imaging; in current literature, this is mostly on latest generation high-end CT systems. PURPOSE: To evaluate the effects of reduced tube current on objective and subjective image quality of a 15-year-old 16-slice CT system for pulmonary angiography (CTPA). MATERIAL AND METHODS: CTPA scans from 60 prospectively randomized patients (28 men, 32 women) were examined in this study on a 15-year-old 16-slice CT scanner system. Standard CT (SD) settings were 100 kV and 150 mAs, LD settings were 100 kV and 50 mAs. Attenuation of the pulmonary trunk, various anatomic landmarks, and image noise were quantitatively measured; contrast-to-noise ratios (CNR) and signal-to-noise ratios (SNR) were calculated. Three independent blinded radiologists subjectively rated each image series using a 5-point grading scale. RESULTS: CT dose index (CTDI) in the LD series was 66.46% lower compared to the SD settings (2.49 ± 0.55 mGy versus 7.42 ± 1.17 mGy). Attenuation of the pulmonary trunk showed similar results for both series (SD 409.55 ± 91.04 HU; LD 380.43 HU ± 93.11 HU; P = 0.768). Subjective image analysis showed no significant differences between SD and LD settings regarding the suitability for detection of central and peripheral PE (central SD/LD, 4.88; intra-class correlation coefficients [ICC], 0.894/4.83; ICC, 0.745; peripheral SD/LD, 4.70; ICC, 0.943/4.57; ICC, 0.919; all P > 0.4). CONCLUSION: The LD protocol, on a 15-year-old CT scanner system without current high-end hardware or post-processing tools, led to a dose reduction of approximately 67% with similar subjective image quality and delineation of central and peripheral pulmonary arteries.

Noise-optimized advanced image-based virtual monoenergetic imaging for improved visualization of lung cancer: Comparison with traditional virtual monoenergetic imaging.

PURPOSE: To assess the effect of a noise-optimized image-based virtual monoenergetic imaging (VMI+) algorithm in direct comparison with the traditional VMI technique and standard linearly-blended images emulating 120-kVp acquisition (M_0.3) on image quality at dual-energy CT in patients with lung cancer. MATERIALS AND METHODS: Dual-source dual-energy CT examinations of 48 patients with biopsy-proven primary (n=31) or recurrent (n=20) lung cancer were evaluated. Images were reconstructed as M_0.3, and VMI+ and traditional VMI series at 40, 55, and 70keV. Attenuation of tumor, descending aorta, pulmonary trunk, latissimus muscle, and noise were measured. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Five-point scales were used by three observers to subjectively evaluate general image impression, tumor delineation, image sharpness, and image noise. RESULTS: Background noise was consistently lower with VMI+ compared to VMI at all keV levels (all p<0.0001) and M_0.3 (all p≤0.0004). Tumor SNR and CNR peaked in the 40keV VMI+ series, significantly higher compared to all VMI and M_0.3 series (all p<0.0008). Observers preferred the 55keV VMI+ series regarding general image impression and tumor delineation compared to all other series (all p<0.0001). Image sharpness and image noise ratings were highest in the 55keV VMI+ and 70keV VMI and VMI+ reconstructions. CONCLUSIONS: Tumor CNR peaked at 40keV VMI+ while observers preferred 55keV VMI+ series overall other series for dual-energy CT of lung cancer. The noise-optimized VMI+ technique showed significantly lower background noise and higher SNR and CNR compared to the traditional VMI technique at matching keV levels.

Single-source chest-abdomen-pelvis cancer staging on a third generation dual-source CT system: comparison of automated tube potential selection to second generation dual-source CT.

BACKGROUND: Evaluation of latest generation automated attenuation-based tube potential selection (ATPS) impact on image quality and radiation dose in contrast-enhanced chest-abdomen-pelvis computed tomography examinations for gynaecologic cancer staging. METHODS: This IRB approved single-centre, observer-blinded retrospective study with a waiver for informed consent included a total of 100 patients with contrast-enhanced chest-abdomen-pelvis CT for gynaecologic cancer staging. All patients were examined with activated ATPS for adaption of tube voltage to body habitus. 50 patients were scanned on a third-generation dual-source CT (DSCT), and another 50 patients on a second-generation DSCT. Predefined image quality setting remained stable between both groups at 120 kV and a current of 210 Reference mAs. Subjective image quality assessment was performed by two blinded readers independently. Attenuation and image noise were measured in several anatomic structures. Signal-to-noise ratio (SNR) was calculated. For the evaluation of radiation exposure, CT dose index (CTDIvol) values were compared. RESULTS: Diagnostic image quality was obtained in all patients. The median CTDIvol (6.1 mGy, range 3.9-22 mGy) was 40 % lower when using the algorithm compared with the previous ATCM protocol (median 10.2 mGy · cm, range 5.8-22.8 mGy). A reduction in potential to 90 kV occurred in 19 cases, a reduction to 100 kV in 23 patients and a reduction to 110 kV in 3 patients of our experimental cohort. These patients received significantly lower radiation exposure compared to the former used protocol. CONCLUSION: Latest generation automated ATPS on third-generation DSCT provides good diagnostic image quality in chest-abdomen-pelvis CT while average radiation dose is reduced by 40 % compared to former ATPS protocol on second-generation DSCT.

First performance evaluation of software for automatic segmentation, labeling and reformation of anatomical aligned axial images of the thoracolumbar spine at CT.

OBJECTIVES: To evaluate software for automatic segmentation, labeling and reformation of anatomical aligned axial images of the thoracolumbar spine on CT in terms of accuracy, potential for time savings and workflow improvement. MATERIAL AND METHODS: 77 patients (28 women, 49 men, mean age 65.3±14.4 years) with known or suspected spinal disorders (degenerative spine disease n=32; disc herniation n=36; traumatic vertebral fractures n=9) underwent 64-slice MDCT with thin-slab reconstruction. Time for automatic labeling of the thoracolumbar spine and reconstruction of double-angulated axial images of the pathological vertebrae was compared with manually performed reconstruction of anatomical aligned axial images. Reformatted images of both reconstruction methods were assessed by two observers regarding accuracy of symmetric depiction of anatomical structures. RESULTS: In 33 cases double-angulated axial images were created in 1 vertebra, in 28 cases in 2 vertebrae and in 16 cases in 3 vertebrae. Correct automatic labeling was achieved in 72 of 77 patients (93.5%). Errors could be manually corrected in 4 cases. Automatic labeling required 1min in average. In cases where anatomical aligned axial images of 1 vertebra were created, reconstructions made by hand were significantly faster (p<0.05). Automatic reconstruction was time-saving in cases of 2 and more vertebrae (p<0.05). Both reconstruction methods revealed good image quality with excellent inter-observer agreement. CONCLUSION: The evaluated software for automatic labeling and anatomically aligned, double-angulated axial image reconstruction of the thoracolumbar spine on CT is time-saving when reconstructions of 2 and more vertebrae are performed. Checking results of automatic labeling is necessary to prevent errors in labeling.

70 kVp computed tomography pulmonary angiography: potential for reduction of iodine load and radiation dose.

PURPOSE: The purpose of the study was to evaluate 70 kVp dual-source computed tomography pulmonary angiography (CTPA) with reduced iodine load in comparison with single-source 70 and 100 kVp CTPA with standard iodine load regarding image quality and radiation dose. MATERIALS AND METHODS: Three groups with 40 consecutive patients each underwent either standard single-source 100 kVp (120 mAs; group A), single-source 70 kVp (208 mAs; group B), or dual-source 70 kVp CTPA (416 mAs; group C). A volume of 70 mL of contrast material with 400 mg I/mL (groups A, B) or 300 mg I/mL (group C) was administered. Chest diameter, dose-length product, intravascular signal attenuation, image noise, signal to noise ratio (SNR), and contrast to noise ratio (CNR) were compared. Two observers rated subjective image quality regarding intravascular enhancement and image noise using 5-point scales. RESULTS: Chest diameter and age were similar (P ≥ 0.28) for all groups. Compared with group A, the average dose-length product was 59% lower in group B (67.3 ± 11.8 vs. 164.7 ± 50.6 mGy cm, P<0.001) and similar between groups A and C (167.7 ± 41.2 mGy cm, P = 0.39). Average SNR and CNR were significantly higher for group C (21.5 ± 4.7 and 19.0 ± 4.5, respectively) compared with groups A (18.3 ± 3.5 and 15.8 ± 3.4, respectively) and B (17.3 ± 5.8 and 15.6 ± 5.5, respectively; all Ps ≤ 0.001). Subjective image quality ratings regarding enhancement and noise were highest for group C (1.73 ± 0.62 and 2.03 ± 0.66, respectively). CONCLUSIONS: Compared with standard 100 kVp CTPA, single-source 70 kVp CTPA allows for significant radiation dose savings with comparable SNR and CNR, whereas dual-source 70 kVp CTPA results in a superior objective image quality albeit a reduction of iodine concentration.