[Show abstract][Hide abstract] ABSTRACT: Purpose: To assess how ASIR (adaptive statistical iterative reconstruction) contributes to dose reduction and affects image quality of non-contrast cranial computed tomography (cCT). Materials and Methods: Non-contrast emergency CT scans of the head acquired in 177 patients were evaluated. The scans were acquired and processed using four different protocols: Group A (control): 120 kV, FBP (filtered back projection) n = 71; group B1: 120 kV, scan and reconstruction performed with 20 % ASIR (blending of 20 % ASIR and 80 % FBP), n = 86; group B2: raw data from group B1 reconstructed using a blending of 40 % ASIR and 60 % FBP, n = 74; group C1: 120 kV, scan and reconstruction performed with 30 % ASIR, n = 20; group C2: raw data from group C1 reconstructed using a blending of 50 % ASIR and 50 % FBP, n = 20. The effective dose was calculated. Image quality was assessed quantitatively and qualitatively. Results: Compared to group A, groups B1/2 and C1/2 showed a significantly reduced effective dose of 40.4 % and 73.3 % (p < 0.0001), respectively. Group B1 and group C1/2 also showed significantly reduced quantitative and qualitative image quality parameters. In group B2, quantitative measures were comparable to group A, and qualitative scores were lower compared to group A but higher compared to group B1. Diagnostic confidence grading showed groups B1/2 to be adequate for everyday clinical practice. Group C2 was considered acceptable for follow-up imaging of severe acute events such as bleeding or subacute stroke. Conclusion: Use of ASIR makes it possible to reduce radiation significantly while maintaining adequate image quality in non-contrast head CT, which may be particularly useful for younger patients in an emergency setting and in follow-up. Key Points: • ASIR may reduce radiation significantly while maintaining adequate image quality• cCT protocol with 20 % ASIR and 40 %ASIR/60 %FBP blending is adequate for everyday clinical use• cCT protocol with 30 % ASIR and 50 %ASIR/50 %FBP blending is adequate for follow-up imaging Citation Format: • Kaul D, Kahn J, Huizing L et al. Reducing Radiation Dose in Adult Head CT using Iterative Reconstruction - A Clinical Study in 177 Patients. Fortschr Röntgenstr 2015; DOI: 10.1055/s-0041-107200.
RöFo - Fortschritte auf dem Gebiet der R 11/2015; DOI:10.1055/s-0041-107200 · 1.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective
. The aim of this study was to visualize soft tissue inflammation using FOI on patients with Systemic Sclerosis (SSc) characterized by SSc-related Raynaud’s phenomenon and to detect the therapeutic response to treatment with iloprost or alprostadil.
. Twenty-one patients with SSc and Raynaud’s phenomenon and twenty-six healthy controls were prospectively included. The SSc patients were intravenously treated with iloprost or alprostadil over seven days. FOI was performed at baseline and after seven days using an intravenous application of indocyanine green (ICG). The hands were divided into nineteen segments per hand. All segments were quantitatively evaluated to determine changes in ICG.
. The sensitivity and specificity of FOI in the detection of ICG enhancement in patients with SSc were 95% versus 96%. At baseline, 31.5% hand segments showed ICG enhancement. After seven days of either iloprost or alprostadil therapy a significant reduction in the ICG was observed which ranged from 40.9% to 24.7%.
. The study demonstrates that the FOI technique is able to visualize soft-tissue inflammation with both high sensitivity and specificity. The anti-inflammatory therapeutic effects of iloprost were slightly stronger than alprostadil. FOI offers promising benefits in the diagnosis and therapy of patients with SSc-associated Raynaud’s phenomenon.
[Show abstract][Hide abstract] ABSTRACT: To evaluate whether magnetic resonance imaging (MRI) is effective as computed tomography (CT) in determining morphologic and functional pulmonary changes in patients with cystic fibrosis (CF) in association with multiple clinical parameters.
Institutional review board approval and patient written informed consent were obtained. In this prospective study, 30 patients with CF (17 men and 13 women; mean (SD) age, 30.2 (9.2) years; range, 19-52 years) were included. Chest CT was acquired by unenhanced low-dose technique for clinical purposes. Lung MRI (1.5 T) comprised T2- and T1-weighted sequences before and after the application of 0.1-mmol·kg gadobutrol, also considering lung perfusion imaging. All CT and MR images were visually evaluated by using 2 different scoring systems: the modified Helbich and the Eichinger scores. Signal intensity of the peribronchial walls and detected mucus on T2-weighted images as well as signal enhancement of the peribronchial walls on contrast-enhanced T1-weighted sequences were additionally assessed on MRI. For the clinical evaluation, the pulmonary exacerbation rate, laboratory, and pulmonary functional parameters were determined.
The overall modified Helbich CT score had a mean (SD) of 15.3 (4.8) (range, 3-21) and median of 16.0 (interquartile range [IQR], 6.3). The overall modified Helbich MR score showed slightly, not significantly, lower values (Wilcoxon rank sum test and Student t test; P > 0.05): mean (SD) of 14.3 (4.7) (range, 3-20) and median of 15.0 (IQR, 7.3). Without assessment of perfusion, the overall Eichinger score resulted in the following values for CT vs MR examinations: mean (SD), 20.3 (7.2) (range, 4-31); and median, 21.0 (IQR, 9.5) vs mean (SD), 19.5 (7.1) (range, 4-33); and median, 20.0 (IQR, 9.0). All differences between CT and MR examinations were not significant (Wilcoxon rank sum tests and Student t tests; P > 0.05). In general, the correlations of the CT scores (overall and different imaging parameters) to the clinical parameters were slightly higher compared to the MRI scores. However, if all additional MRI parameters were integrated into the scoring systems, the correlations reached the values of the CT scores. The overall image quality was significantly higher for the CT examinations compared to the MRI sequences.
One major diagnostic benefit of lung MRI in CF is the possible acquisition of several different morphologic and functional imaging features without the use of any radiation exposure. Lung MRI shows reliable associations with CT and clinical parameters, which suggests its implementation in CF for routine diagnosis, which would be particularly important in follow-up imaging over the long term.
[Show abstract][Hide abstract] ABSTRACT: The established scoring techniques based on radiographs present limitations in the evaluation of structural integrity due to high effectiveness of innovative therapeutic strategies. The aim of this study was to evaluate the periarticular mineralisation as detected by Digital X-ray Radiogrammetry (DXR) as surrogate marker for structural integrity during the course of rheumatoid arthritis (RA).
11 centers throughout Germany contributed data of 94 patients with verified RA. The patients were treated with leflunomide or methotrexate during a mean observation period of 22 months. All patients underwent complete computerized calculations of bone mineral density (BMD) and metacarpal index (MCI) by DXR using digitized hand radiographs. The radiological assessment of disease progression was estimated by the Sharp Score.
The Sharp Score revealed no significant change during the study period. DXR-BMD revealed minimal decrease of -1.4 % (leflunomide group) versus a higher reduction of -4.3 % (methotrexate group). Regarding DXR-MCI, a reduction of -2.2 % (leflunomide group) and -4.9 % (methotrexate group) was observed.
Quantitative data of hand bone mass estimated by the presented DXR-technique may be a complementary precise tool in the identification of RA-related radiographic changes and in the assessment of structural integrity.
[Show abstract][Hide abstract] ABSTRACT: Background Digital X-ray Radiogrammetry (DXR) is a computer based technique to quantify cortical hand bone mineral density (BMD) as well as metacarpal index (MCI) at the metacarpal bones from radiographs in patients with rheumatoid arthritis (RA).
Objectives The objective was to compare DXR-BMD and DXR-MCI between healthy individuals and patients with RA and verify the sensitivity and specificity of this technique for the identification of cortical hand bone loss as an additional diagnostic approach in RA.
Methods In total, 976 patients were enrolled and divided into two groups; those with RA (n=333) and a healthy control group (n=643) as a reference data base. Bone DXR-BMD and the DXR-MCI were measured by DXR using hand radiographs. Severity of RA was evaluated by the modified Larsen Score.
Results The mean values for DXR-BMD and DXR-MCI in RA patients were significantly lower compared to the healthy subjects (23.7% and 22.7%). Depending on the severity of joint damage RA, DXR-BMD revealed a significant reduction of –27.9% and DXR-MCI –28.3%, comparing score 1 and Score 5 of the modified Larsen Score. Both DXR-BMD and DXR-MCI had a high sensitivity (DXR-BMD 95%; DXR-MCI 92%) and moderate specificity (DXR-BMD 48%, DXR-MCI 51%) to identify RA related cortical hand bone loss.
Conclusions The DXR-technique is able to quantify RA-related periarticular bone loss as a typical feature in the course of RA. Consequently, in this case periarticular osteoporosis seems to function as a reliable diagnostic approach comparable to erosions and joint space narrowing in the diagnosis of RA and as a surrogate marker for the progression of bone damage in RA.
Disclosure of Interest None declared
Annals of the Rheumatic Diseases 06/2015; 74(Suppl 2):635.1-635. DOI:10.1136/annrheumdis-2015-eular.3418 · 10.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The first objective of this study was to determine normative digital X-ray radiogrammetry (DXR) values, based on original digital images, in a pediatric population (aged 6-18 years). The second aim was to compare these reference data with patients suffering from distal radius fractures, whereas both cohorts originated from the same geographical region and were evaluated using the same technical parameters as well as inclusion and exclusion criteria. DXR-BMD and DXR-MCI of the metacarpal bones II-IV were assessed on standardized digital hand radiographs, without printing or scanning procedures. DXR parameters were estimated separately by gender and among six age groups; values in the fracture group were compared to age- and gender-matched normative data using Student's t tests and Z scores. In the reference cohort (150 boys, 138 girls), gender differences were found in bone mineral density (DXR-BMD), with higher values for girls from 11 to 14 years and for boys from 15 to 18 years (p < 0.05). Girls had higher normative metacarpal index (DXR-MCI) values than boys, with significant differences at 11-14 years (p < 0.05). In the case-control investigation, the fracture group (95 boys, 69 girls) presented lower DXR-BMD at 15-18 years in boys and 13-16 years in girls vs. the reference cohort (p < 0.05); DXR-MCI was lower at 11-18 years in boys and 11-16 years in girls (p < 0.05). Mean Z scores in the fracture group for DXR-BMD were -0.42 (boys) and -0.46 (girls), and for DXR-MCI were -0.51 (boys) and -0.53 (girls). These findings indicate that the fully digital DXR technique can be accurately applied in pediatric populations ≥ 6 years of age. The lower DXR-BMD and DXR-MCI values in the fracture group suggest promising early identification of individuals with increased fracture risk, without the need for additional radiation exposure, enabling the initiation of prevention strategies to possibly reduce the incidence of osteoporosis later in life.
Journal of Bone and Mineral Metabolism 02/2015; DOI:10.1007/s00774-014-0641-3 · 2.46 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objectives
To compare intraindividually two macrocyclic contrast agents - gadobutrol and gadoterate meglumine (Gd-DOTA) - for dynamic and quantitative assessment of relative enhancement (RE) in benign and malignant breast lesions.
This was an ethically approved, prospective, single-centre, randomized, crossover study in 52 women with suspected breast lesions referred for magnetic resonance imaging (MRI). Each patient underwent one examination with gadobutrol and one with Gd-DOTA (0.1 mmol/kg BW) on a 1.5 T system 1 – 7 days apart. Dynamic, T1-weighted, 3D gradient echo sequences were acquired under identical conditions. Quantitative evaluation with at least three regions of interest (ROI) per lesion was performed. Primary endpoint was RE during the initial postcontrast phase after the first and second dynamic acquisition, and peak RE. All lesions were histologically proven; differences between the examinations were evaluated.
Forty-five patients with a total of 11 benign and 34 malignant lesions were assessed. Mean RE was significantly higher for gadobutrol than Gd-DOTA (p
European Radiology 09/2014; 25(3). DOI:10.1007/s00330-014-3426-0 · 4.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective:
Digital X-ray radiogrammetry (DXR) is a computer-assisted technique used to quantify cortical bone density of the metacarpals. The influence of metacarpal bone rotation and type of cast material on bone mineral density (BMD) measurements using the DXR technique was tested.
The bone mineral density of the hand was measured by DXR, and rotation error (DXR-RE) as coefficients of variation were calculated, to verify reliability and reproducibility of this radiogeometric technique to assess in particular minor disease-related changes in the metacarpal bone mass. The reproducibility of the DXR measurements was also investigated using different cast materials (mull, elastic, and plastic).
There were no significant changes in absolute values of DXR-BMD observed between 0 to [Formula: see text] angulation. The relative DXR-RE ranged between 0 % (degree 1) and 0.70 % (degrees 15 and 19) for DXR-BMD. Regarding the different cast materials, DXR-BMD revealed a coefficient of variation with 0.41 % (mull cast) and 0.21 % (elastic cast). For the plastic cast, the DXR technique was not able to perform an analysis of DXR-BMD.
The study revealed no significant influence of metacarpal rotation on the measurements of metacarpal bone mineral density as estimated by DXR. DXR measurements are not optimal when cast material is used. DXR can accurately quantify periarticular cortical bone mass. This is significant especially for rheumatoid arthritis and related conditions where X-ray imaging of arthritic hands with varying degrees of deformity is performed.
International Journal of Computer Assisted Radiology and Surgery 07/2014; 10(5). DOI:10.1007/s11548-014-1076-y · 1.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to compare contrast-enhanced spectral mammography (CESM) with mammography (MG) and combined CESM + MG in terms of detection and size estimation of histologically proven breast cancers in order to assess the potential to reduce radiation exposure. A total of 118 patients underwent MG and CESM and had final histological results. CESM was performed as a bilateral examination starting 2 min after injection of iodinated contrast medium. Three independent blinded radiologists read the CESM, MG, and CESM + MG images with an interval of at least 4 weeks to avoid case memorization. Sensitivity and size measurement correlation and differences were calculated, average glandular dose (AGD) levels were compared, and breast densities were reported. Fisher's exact and Wilcoxon tests were performed. A total of 107 imaging pairs were available for analysis. Densities were ACR1: 2, ACR2: 45, ACR3: 42, and ACR4: 18. Mean AGD was 1.89 mGy for CESM alone, 1.78 mGy for MG, and 3.67 mGy for the combination. In very dense breasts, AGD of CESM was significantly lower than MG. Sensitivity across readers was 77.9 % for MG alone, 94.7 % for CESM, and 95 % for CESM + MG. Average tumor size measurement error compared to postsurgical pathology was -0.6 mm for MG, +0.6 mm for CESM, and +4.5 mm for CESM + MG (p < 0.001 for CESM + MG vs. both modalities). CESM alone has the same sensitivity and better size assessment as CESM + MG and was significantly better than MG with only 6.2 % increase in AGD. The combination of CESM + MG led to systematic size overestimation. When a CESM examination is planned, additional MG can be avoided, with the possibility of saving up to 61 % of radiation dose, especially in patients with dense breasts.
Breast Cancer Research and Treatment 07/2014; 146(2). DOI:10.1007/s10549-014-3023-6 · 3.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In contrast to conventional breast imaging techniques, one major diagnostic benefit of breast magnetic resonance imaging (MRI) is the simultaneous acquisition of morphologic and dynamic enhancement characteristics, which are based on angiogenesis and therefore provide insights into tumor pathophysiology. The aim of this investigation was to intraindividually compare 2 macrocyclic MRI contrast agents, with low risk for nephrogenic systemic fibrosis, in the morphologic and dynamic characterization of histologically verified mass breast lesions, analyzed by blinded human evaluation and a fully automatic computer-assisted diagnosis (CAD) technique.
Institutional review board approval and patient informed consent were obtained. In this prospective, single-center study, 45 women with 51 histopathologically verified (41 malignant, 10 benign) mass lesions underwent 2 identical examinations at 1.5 T (mean time interval, 2.1 days) with 0.1-mmol kg doses of gadoteric acid and gadobutrol. All magnetic resonance images were visually evaluated by 2 experienced, blinded breast radiologists in consensus and by an automatic CAD system, whereas the morphologic and dynamic characterization as well as the final human classification of lesions were performed based on the categories of the Breast imaging reporting and data system MRI atlas. Lesions were also classified by defining their probability of malignancy (morpho-dynamic index; 0%-100%) by the CAD system. Imaging results were correlated with histopathology as gold standard.
The CAD system coded 49 of 51 lesions with gadoteric acid and gadobutrol (detection rate, 96.1%); initial signal increase was significantly higher for gadobutrol than for gadoteric acid for all and the malignant coded lesions (P < 0.05). Gadoteric acid resulted in more postinitial washout curves and fewer continuous increases of all and the malignant lesions compared with gadobutrol (CAD hot spot regions, P < 0.05). Morphologically, the margins of the malignancies were different between the 2 agents, whereas gadobutrol demonstrated more spiculated and fewer smooth margins (P < 0.05). Lesion classifications by the human observers and by the morpho-dynamic index compared with the histopathologic results did not significantly differ between gadoteric acid and gadobutrol.
Macrocyclic contrast media can be reliably used for breast dynamic contrast-enhanced MRI. However, gadoteric acid and gadobutrol differed in some dynamic and morphologic characterization of histologically verified breast lesions in an intraindividual, comparison. Besides the standardization of technical parameters and imaging evaluation of breast MRI, the standardization of the applied contrast medium seems to be important to receive best comparable MRI interpretation.
[Show abstract][Hide abstract] ABSTRACT: To evaluate postinterventional magnetic resonance imaging (MRI) characteristics following MRI-guided laser ablation of osteoid osteoma (OO).
35 patients treated with MRI-guided laser ablation underwent follow-up MRI immediately after the procedure, after 3, 6, 12, 24, 36, and up to 48 months. The imaging protocol included multiplanar fat-saturated T2w TSE, unenhanced and contrast-enhanced T1w SE, and subtraction images. MR images were reviewed regarding the appearance and size of treated areas, and presence of periablation bone and soft tissue changes. Imaging was correlated with clinical status.
Mean follow-up time was 13.6 months. 28/35 patients (80%) showed a postinterventional "target-sign" appearance consisting of a fibrovascular rim zone and a necrotic core area. After an initial increase in total lesion diameter after 3 months, a subsequent progressive inward remodeling process of the zonal compartments was observed for up to 24 months. Periablation bone and soft tissue changes showed a constant decrease over time. MR findings correlated well with the clinical status. Clinical success was achieved in 32/35 (91%).
Evaluation of long-term follow-up MRI after laser ablation of OO identified typical postinterventional changes and thus may contribute to the interpretation of therapeutic success and residual or recurrent OO in suspected cases.
European journal of radiology 01/2014; 83(4). DOI:10.1016/j.ejrad.2013.12.018 · 2.37 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective. This study aims to assess the impact of adaptive statistical iterative reconstruction (ASIR) on CT imaging quality, diagnostic interpretability, and radiation dose reduction for a proven CT acquisition protocol for total body trauma. Methods. 18 patients with multiple trauma (ISS ≥ 16) were examined either with a routine protocol (n = 6), 30% (n = 6), or 40% (n = 6) of iterative reconstruction (IR) modification in the raw data domain of the routine protocol (140 kV, collimation: 40, noise index: 15). Study groups were matched by scan range and maximal abdominal diameter. Image noise was quantitatively measured. Image contrast, image noise, and overall interpretability were evaluated by two experienced and blinded readers. The amount of radiation dose reductions was evaluated. Results. No statistically significant differences between routine and IR protocols regarding image noise, contrast, and interpretability were present. Mean effective dose for the routine protocol was 25.3 ± 2.9 mSv, 19.7 ± 5.8 mSv for the IR 30, and 17.5 ± 4.2 mSv for the IR 40 protocol, that is, 22.1% effective dose reduction for IR 30 (P = 0.093) and 30.8% effective dose reduction for IR 40 (P = 0.0203). Conclusions. IR does not reduce study interpretability in total body trauma protocols while providing a significant reduction in effective radiation dose.