Ralf W Bauer

Medical University of South Carolina, Charleston, South Carolina, United States

Are you Ralf W Bauer?

Claim your profile

Publications (107)222.15 Total impact

  • Ralf W. Bauer, Sebastian Fischer
    [Show abstract] [Hide abstract]
    ABSTRACT: Dual-energy CT (DECT) is a steadily emerging innovative imaging modality. Various applications have been developed and applied to successfully solve diagnostic difficulties that standard CT has in the abdomen. This includes kidney stone differentiation, cholesterol gallstone detection, renal and adrenal lesion characterization, and tumor response monitoring. This article is supposed to give a current update on possible applications of DECT in the abdomen and their evidence.
    04/2015; 3(4). DOI:10.1007/s40134-015-0090-3
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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. 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). 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). 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.
    Neuroradiology 03/2015; DOI:10.1007/s00234-015-1512-x · 2.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To define optimal keV settings for advanced monoenergetic (Mono+) dual-energy computed tomography (DECT) in patients with head and neck squamous cell carcinoma (SCC). 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. 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). 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. • 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.
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study was done to investigate the dynamic changes of the aortic root during systole and diastole in patients with coronary artery calcification (CAC) using dual-source computed tomography (DSCT). We retrospectively analysed 77 consecutive patients who underwent calcium-scoring and angiographic cardiac DSCT. The long- and short-axis dimensions, axis areas of the aortic annulus, sinotubular junction and ascending aorta at the level of the pulmonary trunk in diastole and systole were measured. Average dimensions and relative areal changes between diastole and systole (%RA) of aortic annulus, sinotubular junction and ascending aorta were compared. Systolic and diastolic long- and short-axis dimensions of the aortic annulus in patients with CAC (n = 44) demonstrated statistically significant differences (27.00 ± 2.84 mm vs. 28.04 ± 2.62 mm; P < 0.001; 21.78 ± 2.55 mm vs. 20.88 ± 2.31 mm; P < 0.001), while differences in average diameters and areas of the aortic annulus were nonsignificant (P > 0.586). Systolic and diastolic axial areas of the sinotubular junction in patients with CAC demonstrated significant differences (7.21 ± 1.80 cm(2) vs. 6.92 ± 1.75 cm(2); P < 0.001). The %RA of the ascending aorta in patients with severe CAC (CAC score >400; n = 15) was significantly reduced compared to patients with minimal-to-moderate CAC (CAC score <400; n = 29; 4.77 ± 2.88 vs. 7.51 ± 3.81, P = 0.014). In comparison with patients without CAC, the long- and short-axis dimensions of the aortic annulus and areas of the sinotubular junction show significant differences during the cardiac cycle in patients with CAC. The presence of severe CAC significantly influences the flexibility of the wall of the ascending aorta.
    La radiologia medica 02/2015; DOI:10.1007/s11547-015-0503-7 · 1.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Sliding-gantry computed tomography offers an interesting variety of treatment options for emergency radiology and clinical routine. The Frankfurt 2-room installation provides an interdisciplinary, multifunctional, and cost-effective concept. It is based on a magnetically sealed rail system for the permanent movement of the gantry between 2 adjacent rooms with fixed-mounted tables. In case of emergency or intensive care patients, routine scanning can be performed in room 1 until computed tomography diagnosis is required in room 2 and can then be continued in room 1 again. Moreover, this concept allows the simultaneous handling of 2 emergency patients.
    Journal of Computer Assisted Tomography 01/2015; DOI:10.1097/RCT.0000000000000199 · 1.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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. 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. 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. 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. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
    European Journal of Radiology 12/2014; DOI:10.1016/j.ejrad.2014.11.043 · 2.16 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate quantitative dual-energy computed tomography (DECT) for phantomless analysis of cancellous bone mineral density (BMD) of vertebral pedicles and to assess the correlation with pedicle screw pull-out strength. Twenty-nine thoracic and lumbar vertebrae from cadaver specimens were examined with DECT. Using dedicated post-processing software, a pedicle screw vector was mapped (R1, intrapedicular segment of the pedicle vector; R2, intermediate segment; R3, intracorporal segment; global, all segments) and BMD was calculated. To invasively evaluate pedicle stability, pedicle screws were drilled through both pedicles and left pedicle screw pull-out strength was measured. Resulting values were correlated using the paired t test and Pearson's linear correlation. Average pedicle screw vector BMD (R1, 0.232 g/cm(3); R2, 0.166 g/cm(3); R3, 0.173 g/cm(3); global, 0.236 g/cm(3)) showed significant differences between R1-R2 (P < 0.002) and R1-R3 (P < 0.034) segments while comparison of R2-R3 did not reach significance (P > 0.668). Average screw pull-out strength (639.2 N) showed a far stronger correlation with R1 (r = 0.80; P < 0.0001) than global BMD (r = 0.42; P = 0.025), R2 (r = 0.37; P = 0.048) and R3 (r = -0.33; P = 0.078) segments. Quantitative DECT allows for phantomless BMD assessment of the vertebral pedicle. BMD of the intrapedicular segment shows a significantly stronger correlation with pedicle screw pull-out strength than other segments. • Quantitative dual-energy CT enables evaluation of pedicle bone mineral density. • Intrapedicular segments show significant differences regarding bone mineral density. • Pedicle screw pull-out strength correlated strongest with R1 values. • Dual-energy CT may improve preoperative assessment before transpedicular screw fixation.
    European Radiology 12/2014; DOI:10.1007/s00330-014-3529-7 · 4.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To compare non-linear and linear image-blending post-processing techniques in dual-energy CT (DECT) of primary head and neck squamous cell carcinoma (SCC) regarding subjective and objective image quality. Head and neck DECT studies from 69 patients (48 male, 21 female; mean age 62.3 years) were retrospectively evaluated. All tumour lesions were histologically confirmed SCC. Linearly blended 80/140 kVp images series with varying weighting factors of 0.3 (M_0.3), 0.6 and 0.8 were compared with non-linearly blended images. Attenuation of tumour lesion, various soft-tissue structures, the internal jugular vein, and image noise were measured, tumour signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Overall image quality, delineation of tumour lesion, image sharpness, and noise level were rated individually by three radiologists using five-point Likert scales. Interobserver agreement was calculated using intraclass correlation coefficient (ICC). Enhancement of tumour lesions (non-linear, 137.5 ± 20.1 HU; M_0.3, 92.7 ± 14.4 HU; M_0.6, 110 ± 15.4 HU; M_0.8, 123 ± 18.2 HU), CNR (non-linear, 12 ± 8; M_0.3, 4 ± 4.7; M_0.6, 7.5 ± 5.5; M_0.8, 8 ± 5.5), subjective overall image quality and tumour delineation were significantly increased (all p < 0.001) with the non-linear blending technique compared to all investigated linear blending weighting factors. Overall interobserver agreement was substantial (ICC 0.70; 95% CI: 0.66-0.73). Post-processing of DECT using a non-linear blending technique provides improved objective and subjective image quality of head and neck SCC compared to linearly blended images series. Copyright © 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.
    Clinical Radiology 12/2014; DOI:10.1016/j.crad.2014.10.018 · 1.66 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Evaluation of automated attenuation-based tube potential selection and its impact on image quality and radiation dose in CT (computed tomography) examinations for cancer staging. A total of 110 (59 men, 51 women) patients underwent chest-abdomen-pelvis CT examinations; 55 using a fixed tube potential of 120 kV/current of 210 Reference mAs (using CareDose4D), and 55 using automated attenuation-based tube potential selection (CAREkV) also using a current of 210 Reference mAs. Diagnostic image quality was obtained from all patients. The median DLP (703.5 mGy · cm, range 390-2203 mGy · cm) was 7.9% lower when using the algorithm compared with the standard 120 kV protocol (median 756 mGy · cm, range 345-2267 mGy · cm). A reduction in potential to 100 kV occurred in 32 cases; therefore, these patients received significantly lower radiation exposure compared with the 120 kV protocol. Automated attenuation-based tube potential selection produces good diagnostic image quality in chest-abdomen-pelvis CT and reduces the patient's overall radiation dose by 7.9% compared to the standard 120 kV protocol.
    Cancer imaging : the official publication of the International Cancer Imaging Society 12/2014; 14(1):28. DOI:10.1186/s40644-014-0028-7
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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. 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. 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). 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.
    Journal of Thoracic Imaging 11/2014; 30(1). DOI:10.1097/RTI.0000000000000124 · 1.49 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A sliding gantry trauma room CT solution facilitates significantly faster polytrauma management.•Faster and more efficient resumption of regularly scheduled patients due to a two room solution is supported.•Sliding gantry CT achieves the same patient throughput as two separate conventional CT devices.
    European Journal of Radiology 11/2014; 84(1). DOI:10.1016/j.ejrad.2014.10.013 · 2.16 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Low-tube-voltage acquisition has been shown to facilitate substantial dose savings for neck CT with similar image contrast compared with standard 120-kVp acquisition. However, its potential for the detection of neck pathologies is uncertain. Our aim was to evaluate the effects of low-tube-voltage 80-kV(peak) acquisitions for neck CT on diagnostic accuracy and interobserver agreement.
    American Journal of Neuroradiology 08/2014; 35(12). DOI:10.3174/ajnr.A4052 · 3.68 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To intra-individually compare single-portal-phase low-tube-voltage (100-kVp) computed tomography (CT) with 120-kVp images for short-term follow-up assessment of CT severity index (CTSI) of acute pancreatitis, interobserver agreement and radiation dose.
    European Radiology 07/2014; DOI:10.1007/s00330-014-3300-0 · 4.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective To investigate the impact of automated attenuation-based tube potential selection on image quality and exposure parameters in polytrauma patients undergoing contrast-enhanced thoraco-abdominal CT. Methods One hundred patients were examined on a 16-slice device at 120 kV with 190 ref.mAs and automated mA modulation only. Another 100 patients underwent 128-slice CT with automated mA modulation and topogram-based automated tube potential selection (autokV) at 100, 120 or 140 kV. Volume CT dose index (CTDIvol), dose–length product (DLP), body diameters, noise, signal-to-noise ratio (SNR) and subjective image quality were compared. Results In the autokV group, 100 kV was automatically selected in 82 patients, 120 kV in 12 patients and 140 kV in 6 patients. Patient diameters increased with higher kV settings. The median CTDIvol (8.3 vs. 12.4 mGy; −33 %) and DLP (594 vs. 909 mGy cm; −35 %) in the entire autokV group were significantly lower than in the group with fixed 120 kV (p < 0.05 for both). Image quality remained at a constantly high level at any selected kV level. Conclusion Topogram-based automated selection of the tube potential allows for significant dose savings in thoraco-abdominal trauma CT while image quality remains at a constantly high level. Key Points • Automated kV selection in thoraco-abdominal trauma CT results in significant dose savings • Most patients benefit from a 100-kV protocol with relevant DLP reduction • Constantly good image quality is ensured • Image quality benefits from higher kV when arms are positioned downward
    European Radiology 07/2014; 24(7). DOI:10.1007/s00330-014-3197-7 · 4.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to evaluate the effects on objective and subjective image quality of virtual monoenergetic reconstructions at various energy levels of dual-energy computed tomography (DECT) in patients with head and neck cancer.
    Investigative Radiology 05/2014; DOI:10.1097/RLI.0000000000000077 · 4.45 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To compare non-linear and linear blending of cardiac dual-energy computed tomography (DECT) for optimal visualization of late iodine enhancement (LIE) in patients with chronic myocardial infarction (CMI). LIE-DECT data from 20 patients with known CMI were retrospectively analyzed. Images were reconstructed using non-linear blending center and width settings in the range of 0-500. Linear blending was performed with weighting factors 0.8 (80 % 100 kV, 20 % 140 kV), 0.6 and 0.3. 100-/140-kV data and blended images were analyzed. Contrast and percentage signal differences between infarcted and healthy myocardium and the left ventricle blood pool were computed. Statistical analysis was performed using repeated-measures analysis of variance and post hoc t tests. Non-linear blending showed the highest signal differences for all contrasts and analyses. Repeated-measures ANOVA tests confirmed the statistical differences between the investigated blending techniques (P < 0.01). Paired-samples post hoc t tests confirmed the significance of these results (P < 0.04). The ideal non-linear blending settings for best demarcation of CMI from healthy myocardium were a center of 65.8 ± 23.2 and a width of 0.0 ± 0.0. Non-linear blending of LIE-DECT improves display of LIE in patients with CMI in comparison with linear blending and non-post-processed image data from 100-/140-kV.
    The international journal of cardiovascular imaging 05/2014; 30(6). DOI:10.1007/s10554-014-0440-x · 2.15 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate image quality and diagnostic accuracy of selective monoenergetic reconstructions of late iodine enhancement (LIE) dual-energy computed tomography (DECT) for imaging of chronic myocardial infarction (CMI). Twenty patients with a history of coronary bypass surgery underwent cardiac LIE-DECT and late gadolinium enhancement (LGE) magnetic resonance imaging (MRI). LIE-DECT images were reconstructed as selective monoenergetic spectral images with photon energies of 40, 60, 80, and 100 keV and the standard linear blending setting (M_0.6). Images were assessed for late enhancement, transmural extent, signal characteristics and subjective image quality. Seventy-nine myocardial segments (23 %) showed LGE. LIE-DECT detected 76 lesions. Images obtained at 80 keV and M_0.6 showed a high signal-to-noise ratio (15.9; 15.1), contrast-to-noise ratio (4.2; 4.0) and sensitivity (94.9 %; 92.4 %) while specificity was identical (99.6 %). Differences between these series were not statistically significant. Transmural extent of LIE was overestimated in both series (80 keV: 40 %; M_0.6: 35 %) in comparison to MRI. However, observers preferred 80 keV in 13/20 cases (65 %, κ = 0.634) over M_0.6 (4/20 cases) regarding subjective image quality. Post-processing of LIE-DECT data with selective monoenergetic reconstructions at 80 keV significantly improves subjective image quality while objective image quality shows no significant difference compared to standard linear blending. • Late enhancement dual-energy CT allows for detection of chronic myocardial infarction. • Monoenergetic reconstructions at 80 keV significantly improve subjective image quality. • 80 keV and standard linear blending reconstructions show no significant differences. • Extent of CMI detected with LIE-DECT is overestimated compared with MRI.
    European Radiology 03/2014; DOI:10.1007/s00330-014-3126-9 · 4.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose To evaluate the feasibility of phantomless in vivo dual-energy computed tomography (CT)-based three-dimensional (3D) bone mineral density (BMD) assessment in comparison with dual x-ray absorptiometry (DXA). Materials and Methods This retrospective study was approved by the institutional review board, and the requirement to obtain informed consent was waived. Data from clinically indicated dual-energy CT and DXA examinations within 2 months, comprising the lumbar spine of 40 patients, were included. By using automated dedicated postprocessing dual-energy CT software, the trabecular bone of lumbar vertebrae L1-L4 were analyzed and segmented. A mixed-effects model was used to assess the correlations between BMD values derived from dual-energy CT and DXA. Results One hundred sixty lumbar vertebrae were analyzed in 40 patients (mean age, 57.1 years; range, 24-85 years), 21 male (mean age, 54.3 years; range, 24-85 years) and 19 female (mean age, 58.5 years; range, 31-80 years). Mean BMD of L1-L4 determined with DXA was 0.995 g/cm(2), and 18 patients (45%) showed an osteoporotic BMD (T score less than -2.5) of at least two vertebrae. Mean dual-energy CT-based BMD of L1-L4 was 0.254 g/cm(3). Bland-Altman analysis with mixed effects demonstrated a lack of correlation between dual-energy CT-based and DXA-based BMD values, with a mean difference of 0.7441 and 95% limits of agreement of 0.7441 ± 0.4080. Conclusion Dedicated postprocessing of dual-energy CT data allows for phantomless in vivo BMD assessment of the trabecular bone of lumbar vertebrae and enables freely rotatable color-coded 3D visualization of intravertebral BMD distribution. © RSNA, 2014.
    Radiology 01/2014; 271(3):131952. DOI:10.1148/radiol.13131952 · 6.21 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE To compare the radiation exposure and image quality of coronary CT angiography (cCTA) protocols on a second generation 128-slice dual-source CT (DSCT) scanner. METHOD AND MATERIALS We prospectively included 100 patients referred for cCTA. Patients with a heart rate below 65 bpm were randomized between prospectively ECG-gated high-pitch spiral (group 1) and narrow-window sequential (group 2) acquisition. Patients with a heart rate above 65 bpm were randomly assigned to a retrospectively ECG-gated spiral acquisition protocol in either dual-source (group 3) or dual-energy (group 4) mode. CT dose index volume, dose length product, effective dose, contrast-to-noise and signal-to-noise ratio were compared. Subjective image quality was rated by two observers blinded to the used protocol. RESULTS High-pitch spiral cCTA showed a mean estimated radiation dose of 1.27±0.64 mSv, significantly (p<0.001) lower than sequential mode (2.05±1.18 mSv) and spiral acquisition with DSCT(5.95±2.56 mSv) or DECT (3.82±1.38 mSv). Image noise showed no statistical difference (p>0.05), ranging from 16.03±6.3 (group 1) to 19.3±9.5 (group 4) and 20.1±16.5 (group 2) up to 26.4±23.0 (group 3). Each protocol showed diagnostic image quality in at least 98.4% of evaluated coronary segments. CONCLUSION Prospectively ECG-gated DSCT protocols allow cCTA with significant dose reduction. High-pitch spiral mode generates less than 1/2 of the estimated radiation exposure of sequential acquisition mode. In patients with a heart rate above 65 bpm, dual-energy mode should be preferred over spiral DSCT as it significantly decreases estimated dose without compromising diagnostic image quality. CLINICAL RELEVANCE/APPLICATION Second-generation DSCT scanners allow cCTA in patients with normo- or arrhythmia that result in significant dose reduction while maintaining diagnostic image quality.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE To evaluate the effect of an anti-scatter grid on perceived image quality in adult bedside chest radiographs using both a mobile digital radiography (DR) system and a conventional computed radiography (CR) system. METHOD AND MATERIALS We included 103 intensive-care patients (mean age: 66.4 years). Patients received bedside chest radiographs using four acquisition techniques (CR and DR with and without grid). Image quality was evaluated independently by four radiologists using a 9-point visibility scale. Evaluated were: lung parenchyma, soft tissues, thoracic spine, foreign bodies and overall image quality. Inter-observer agreement and differences between systems were tested using inter-class correlation test. Mean scores were compared by analysis of variance (ANOVA) followed by post-hoc pairwise testing (Tukey test) in case of multiple group comparison and by student’s t-test in case of single group comparison (p < 0.05 = significant). RESULTS The image quality of the DR images with a grid was significantly higher than that obtained without a grid (p<0.001) for all structures. The use of a grid in CR significantly improved the overall image quality, lung parenchyma and soft tissue delineation (p<0.001). Foreign body delineation, however, was significantly better in CR images obtained without a grid (p<0.001), while the two systems showed no significant difference regarding thoracic spine delineation (p=0.554). The DR-images’ scores were significantly higher than the CR-images’ scores for all structures. The inter-observer agreement was substantial for lung parenchyma (ICC=0.77), soft tissue (ICC=0.78), thoracic spine (ICC=0.80) and overall image quality (ICC=0.78) and was almost perfect for foreign bodies (ICC=0.81). CONCLUSION The use of an anti-scatter grid significantly improved the image quality of bedside DR radiographs. A similar effect was seen with CR radiographs but only for lung parenchyma, soft tissue and overall image quality. Mobile DR outperformed CR in all structures. CLINICAL RELEVANCE/APPLICATION In both, CR and DR, the use of grid in adult bedside radiography proved to be beneficial, and significantly improved the perceived image quality.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013

Publication Stats

390 Citations
222.15 Total Impact Points

Institutions

  • 2009–2015
    • Medical University of South Carolina
      • Department of Radiology
      Charleston, South Carolina, United States
  • 2013–2014
    • University Hospital Frankfurt
      Frankfurt, Hesse, Germany
  • 2007–2014
    • Goethe-Universität Frankfurt am Main
      • Institut für Diagnostische und Interventionelle Radiologie
      Frankfurt, Hesse, Germany