Computed tomography of the chest with model-based iterative reconstruction using a radiation exposure similar to chest X-ray examination: preliminary observations

Energy Technology Data Exchange (ETDEWEB)

Neroladaki, Angeliki; Botsikas, Diomidis; Boudabbous, Sana; Becker, Christoph D.; Montet, Xavier [Geneva University Hospital, Department of Radiology, Geneva 4 (Switzerland)

2013-02-15

The purpose of this study was to assess the diagnostic image quality of ultra-low-dose chest computed tomography (ULD-CT) obtained with a radiation dose comparable to chest radiography and reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in comparison with standard dose diagnostic CT (SDD-CT) or low-dose diagnostic CT (LDD-CT) reconstructed with FBP alone. Unenhanced chest CT images of 42 patients acquired with ULD-CT were compared with images obtained with SDD-CT or LDD-CT in the same examination. Noise measurements and image quality, based on conspicuity of chest lesions on all CT data sets were assessed on a five-point scale. The radiation dose of ULD-CT was 0.16 {+-} 0.006 mSv compared with 11.2 {+-} 2.7 mSv for SDD-CT (P < 0.0001) and 2.7 {+-} 0.9 mSv for LDD-CT. Image quality of ULD-CT increased significantly when using MBIR compared with FBP or ASIR (P < 0.001). ULD-CT reconstructed with MBIR enabled to detect as many non-calcified pulmonary nodules as seen on SDD-CT or LDD-CT. However, image quality of ULD-CT was clearly inferior for characterisation of ground glass opacities or emphysema. Model-based iterative reconstruction allows detection of pulmonary nodules with ULD-CT with radiation exposure in the range of a posterior to anterior (PA) and lateral chest X-ray. (orig.)

The measurement of organic radiation dose of multi-slice CT scanning by using the Chinese anthropomorphic chest phantom

International Nuclear Information System (INIS)

Peng Gang; Zeng Yongming; Luo Tianyou; Zhao Feng; Zhang Zhiwei; Yu Renqiang; Peng Shengkun

2011-01-01

Objective: Using the Chinese anthropomorphic chest phantom to measure the absorbed dose of various tissues and organs under different noise index, and to assess the radiation dose of MSCT chest scanning with the effective dose (ED). Methods: The equivalence of the Chinese anthropomorphic chest phantom (CDP-1 C) and the adult chest on CT sectional anatomy and X-ray attenuation was demonstrated. The absorbed doses of various tissues and organs under different noise index were measured by laying thermoluminescent dosimeters (TLD) inside the phantom, and the corresponding dose-length products (DLP) were recorded. Both of them were later converted into ED and comparison was conducted to analyze the dose levels of chest CT scanning with automatic tube current modulation (ATCM) under different noise index. Student t-test was applied using SPSS 12.0 statistical software. Results: The Phantom was similar to the human body on CT sectional anatomy. The average CT value of phantom are - 788.04 HU in lung, 45.64 HU in heart, 65.84 HU in liver, 254.32 HU in spine and the deviations are 0.10%, 3.04%, 4.49% and 4.36% respectively compared to humans. The difference of average CT value of liver was statistically significant (t=-8.705, P 0.05). As the noise index increased from 8.5 to 22.5, the DLP decreased from 393.57 mGy · cm to 78.75 mGy · cm and the organs dose declined. For example, the average absorbed dose decreased from 22.38 mGy to 3.66 mGy in lung. Compared to ED calculating by absorbed dose, the ED calculating by DLP was lower. The ED values of the two methods were 6.69 mSv and 8.77 mSv when the noise index was set at 8.5. Conclusions: Application of the Chinese anthropomorphic chest phantom to carry out CT dose assessment is more accurate. The noise index should be set more than 8.5 during the chest CT scanning based on ATCM technique. (authors)

Comparison of radiation doses between newborns and 6-y-old children undergoing head, chest and abdominal CT examinations-A phantom study

International Nuclear Information System (INIS)

Sugimoto, N.; Aoyama, T.; Koyama, S.; Yamauchi-Kawaura, C.; Fujii, K.

2013-01-01

Radiation doses in paediatric computed tomography (CT) were investigated for various types of recent CT scanners with newborn and 6-y-old phantoms in which silicon-photodiode dosemeters were implanted at various organ positions. In the head, chest and abdominal CT for the newborn phantom, doses for organs within the scan region were 21-40, 3-8 and 3-12 mGy, respectively. The corresponding doses for the child phantom were 20-37, 2-11 and 4-17 mGy, respectively. In the head, chest and abdominal CT, the effective doses were respectively 2.1-3.3, 2.0-6.0 and 2.2-10.0 mSv for the newborn, and 1.0-2.0, 1.2-6.6 and 2.9-11.8 mSv for the child. Radiation doses for the newborn were at the same levels as those for the child, excepting effective doses in head CT for the newborn, which were 1.8 times higher than those for the child. (authors)

Evaluation of Image Quality in Low Tube-Voltage Chest CT Scan

International Nuclear Information System (INIS)

Kim, Hyun Ju; Cho, Jae Hwan; Park, Cheol Soo

2010-01-01

The patients who visited this department for pulmonary disease and need CT scans for Follow-up to observe change of CT value, evaluation of image quality and decrease of radiation dose as change of kVp. Subjects were the patients of 20 persons visited this department for pulmonary disease and Somatom Sensation 16(Semens, Enlarge, Germany) was used. Measurement of CT value as change of kVp was done by setting up ROI diameter of 1cm at the height of thyroid, aortic arch, right pulmonary artery in arterial phase image using 100 kVp, measuring 3 times, and recorded the average. CT value of phantom was measured by scanning phantoms which means contrast media diluted by normal saline by various ratio with tube voltage of 80 kVp, 100 kVp, 120 kVp, 140 kVp and recorded the average of 3 CT values of center of phantom image. In analysing radiation dose, CTDIVOL values of the latest arterial phase image of 120 kVp and as this research set that of 100 kVp were analyzed comparatively. 2 observers graded quality of chest images by 5 degrees (Unacceptable, Suboptimal, Adequate, Good, Excellent). CT value of chest image increased at 100 kVp by 14.06%∼27.26% in each ROI than 120 kVp. CT value of phantom increased as tube voltage lowered at various concentration of contrast media. CTDIVOL decreased at 100 kVp(5.00 mGy) by 36% than 120 kVp(7.80 mGy) in radiation dose analysis. here were 0 Unacceptable, 1 Suboptimal, 3 Adequate, 10 Good, 6 Excellent in totally 20 persons. Chest CT scanning with low kilo-voltage for patients who need CT scan repeatedly can bring images valuable for diagnose, and decrease radiation dose against patients

3D automatic exposure control for 64-detector row CT: Radiation dose reduction in chest phantom study

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, Keiko, E-mail: palm_kei@yahoo.co.jp [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Department of Radiology, Yamanashi University, Shimokato, Yamanashi (Japan); Ohno, Yoshiharu; Koyama, Hisanobu; Kono, Atsushi [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Inokawa, Hiroyasu [Toshiba Medical Systems, Ohtawara, Tochigi (Japan); Onishi, Yumiko [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Nogami, Munenobu [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Division of Image-Based Medicine, Institute of Biomedical Research and Innovation, Kobe, Hyogo (Japan); Takenaka, Daisuke [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Araki, Tsutomu [Department of Radiology, Yamanashi University, Shimokato, Yamanashi (Japan); Sugimura, Kazuro [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan)

2011-03-15

Purpose: The purpose of this study was to determine the utility of three-dimensional (3D) automatic exposure control (AEC) for low-dose CT examination in a chest phantom study. Materials and methods: A chest CT phantom including simulated focal ground-glass opacities (GGOs) and nodules was scanned with a 64-detector row CT with and without AEC. Performance of 3D AEC included changing targeted standard deviations (SDs) of image noise from scout view. To determine the appropriate targeted SD number for identification, the capability of overall identification with the CT protocol adapted to each of the targeted SDs was compared with that obtained with CT without AEC by means of receiver operating characteristic analysis. Results: When targeted SD values equal to or higher than 250 were used, areas under the curve (Azs) of nodule identification with CT protocol using AEC were significantly smaller than that for CT protocol without AEC (p < 0.05). When targeted SD numbers at equal to or more than 180 were adapted, Azs of CT protocol with AEC had significantly smaller than that without AEC (p < 0.05). Conclusion: This phantom study shows 3D AEC is useful for low-dose lung CT examination, and can reduce the radiation dose while maintaining good identification capability and good image quality.

Radiation dose reduction with the adaptive statistical iterative reconstruction (ASIR) technique for chest CT in children: an intra-individual comparison.

Science.gov (United States)

Lee, Seung Hyun; Kim, Myung-Joon; Yoon, Choon-Sik; Lee, Mi-Jung

2012-09-01

To retrospectively compare radiation dose and image quality of pediatric chest CT using a routine dose protocol reconstructed with filtered back projection (FBP) (the Routine study) and a low-dose protocol with 50% adaptive statistical iterative reconstruction (ASIR) (the ASIR study). We retrospectively reviewed chest CT performed in pediatric patients who underwent both the Routine study and the ASIR study on different days between January 2010 and August 2011. Volume CT dose indices (CTDIvol), dose length products (DLP), and effective doses were obtained to estimate radiation dose. The image quality was evaluated objectively as noise measured in the descending aorta and paraspinal muscle, and subjectively by three radiologists for noise, sharpness, artifacts, and diagnostic acceptability using a four-point scale. The paired Student's t-test and the Wilcoxon signed-rank test were used for statistical analysis. Twenty-six patients (M:F=13:13, mean age 11.7) were enrolled. The ASIR studies showed 60.3%, 56.2%, and 55.2% reductions in CTDIvol (from 18.73 to 7.43 mGy, PASIR studies (20.81 vs. 16.67, P=0.004), but was not different in the aorta (18.23 vs. 18.72, P=0.726). The subjective image quality demonstrated no difference between the two studies. A low-dose protocol with 50% ASIR allows radiation dose reduction in pediatric chest CT by more than 55% while maintaining image quality. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Chest CT in children: anesthesia and atelectasis

Energy Technology Data Exchange (ETDEWEB)

Newman, Beverley; Gawande, Rakhee [Lucile Packard Children' s Hospital, Department of Radiology, Stanford, CA (United States); Krane, Elliot J. [Stanford University School of Medicine, Lucile Packard Children' s Hospital, Department of Anesthesiology, Perioperative and Pain Medicine, Stanford, CA (United States); Holmes, Tyson H. [Stanford University School of Medicine, Lucile Packard Children' s Hospital, Department of Psychiatry and Behavioral Sciences, Stanford, CA (United States); Robinson, Terry E. [Stanford University School of Medicine, Lucile Packard Children' s Hospital, Department of Pulmonary Medicine and Cystic Fibrosis Center for Excellence in Pulmonary Biology, Stanford, CA (United States)

2014-02-15

There has been an increasing tendency for anesthesiologists to be responsible for providing sedation or anesthesia during chest CT imaging in young children. Anesthesia-related atelectasis noted on chest CT imaging has proven to be a common and troublesome problem, affecting image quality and diagnostic sensitivity. To evaluate the safety and effectiveness of a standardized anesthesia, lung recruitment, controlled-ventilation technique developed at our institution to prevent atelectasis for chest CT imaging in young children. Fifty-six chest CT scans were obtained in 42 children using a research-based intubation, lung recruitment and controlled-ventilation CT scanning protocol. These studies were compared with 70 non-protocolized chest CT scans under anesthesia taken from 18 of the same children, who were tested at different times, without the specific lung recruitment and controlled-ventilation technique. Two radiology readers scored all inspiratory chest CT scans for overall CT quality and atelectasis. Detailed cardiorespiratory parameters were evaluated at baseline, and during recruitment and inspiratory imaging on 21 controlled-ventilation cases and 8 control cases. Significant differences were noted between groups for both quality and atelectasis scores with optimal scoring demonstrated in the controlled-ventilation cases where 70% were rated very good to excellent quality scans compared with only 24% of non-protocol cases. There was no or minimal atelectasis in 48% of the controlled ventilation cases compared to 51% of non-protocol cases with segmental, multisegmental or lobar atelectasis present. No significant difference in cardiorespiratory parameters was found between controlled ventilation and other chest CT cases and no procedure-related adverse events occurred. Controlled-ventilation infant CT scanning under general anesthesia, utilizing intubation and recruitment maneuvers followed by chest CT scans, appears to be a safe and effective method to obtain

Chest CT in children: anesthesia and atelectasis

International Nuclear Information System (INIS)

Newman, Beverley; Gawande, Rakhee; Krane, Elliot J.; Holmes, Tyson H.; Robinson, Terry E.

2014-01-01

There has been an increasing tendency for anesthesiologists to be responsible for providing sedation or anesthesia during chest CT imaging in young children. Anesthesia-related atelectasis noted on chest CT imaging has proven to be a common and troublesome problem, affecting image quality and diagnostic sensitivity. To evaluate the safety and effectiveness of a standardized anesthesia, lung recruitment, controlled-ventilation technique developed at our institution to prevent atelectasis for chest CT imaging in young children. Fifty-six chest CT scans were obtained in 42 children using a research-based intubation, lung recruitment and controlled-ventilation CT scanning protocol. These studies were compared with 70 non-protocolized chest CT scans under anesthesia taken from 18 of the same children, who were tested at different times, without the specific lung recruitment and controlled-ventilation technique. Two radiology readers scored all inspiratory chest CT scans for overall CT quality and atelectasis. Detailed cardiorespiratory parameters were evaluated at baseline, and during recruitment and inspiratory imaging on 21 controlled-ventilation cases and 8 control cases. Significant differences were noted between groups for both quality and atelectasis scores with optimal scoring demonstrated in the controlled-ventilation cases where 70% were rated very good to excellent quality scans compared with only 24% of non-protocol cases. There was no or minimal atelectasis in 48% of the controlled ventilation cases compared to 51% of non-protocol cases with segmental, multisegmental or lobar atelectasis present. No significant difference in cardiorespiratory parameters was found between controlled ventilation and other chest CT cases and no procedure-related adverse events occurred. Controlled-ventilation infant CT scanning under general anesthesia, utilizing intubation and recruitment maneuvers followed by chest CT scans, appears to be a safe and effective method to obtain

Early appearance of SARS on chest CT scan

International Nuclear Information System (INIS)

Cheng Xiaoguang; Feng Suchen; Xia Guoguang; Zhao Tao; Gu Xiang; Qu Hui

2003-01-01

Objective: To evaluate the early appearance of SARS on chest CT scan and its role in the early diagnosis. Methods: Forty cases of SARS in keeping with the criteria of the Ministry of Health had chest CT scans within 7 days of onset of symptoms, and CR chest X-ray films were available as well. These chest X-rays and CT images were retrospectively reviewed to determine if there were any abnormalities on the images. The lesions on the chest CT images were then further analyzed in terms of the number, location, size, and density. Results: Positive abnormalities on chest CT scans were revealed in all 40 SARS cases. Positive findings on CR chest films were showed in only 25 cases, equivocal in 6, and normal in 9 cases. The main abnormalities seen on CT and X-rays were pulmonary infiltrations varied markedly in severity. 70 % cases had 1 or 2 lesions on chest CT scan, 30 % cases had 3 or more lesions. The lesions seen on chest CT scan tended to be ground-glass opacification, sometimes with consolidation which was very faint and inhomogeneous, easily missed on chest X-rays. Typically the lesions were located in the periphery of the lung, or both central and peripheral lung, but very rare in a pure central location. They were commonly in the shape of patch or ball. Conclusions: Chest CT scan is much more sensitive in detecting the lesions of the lung in SARS. The early appearance of SARS on chest CT scan is characteristic but non-specific, indicating that chest CT scan plays a very important role in the early diagnosis and differential diagnosis of SARS

Is Weight-Based Adjustment of Automatic Exposure Control Necessary for the Reduction of Chest CT Radiation Dose?

Science.gov (United States)

Prakash, Priyanka; Gilman, Matthew D.; Shepard, Jo-Anne O.; Digumarthy, Subba R.

2010-01-01

Objective To assess the effects of radiation dose reduction in the chest CT using a weight-based adjustment of the automatic exposure control (AEC) technique. Materials and Methods With Institutional Review Board Approval, 60 patients (mean age, 59.1 years; M:F = 35:25) and 57 weight-matched patients (mean age, 52.3 years, M:F = 25:32) were scanned using a weight-adjusted AEC and non-weight-adjusted AEC, respectively on a 64-slice multidetector CT with a 0.984:1 pitch, 0.5 second rotation time, 40 mm table feed/rotation, and 2.5 mm section thickness. Patients were categorized into 3 weight categories; 90 kg (n = 48). Patient weights, scanning parameters, CT dose index volumes (CTDIvol) and dose length product (DLP) were recorded, while effective dose (ED) was estimated. Image noise was measured in the descending thoracic aorta. Data were analyzed using a standard statistical package (SAS/STAT) (Version 9.1, SAS institute Inc, Cary, NC). Results Compared to the non-weight-adjusted AEC, the weight-adjusted AEC technique resulted in an average decrease of 29% in CTDIvol and a 27% effective dose reduction (p 91 kg weight groups, respectively, compared to 20.3, 27.9 and 32.8 mGy, with non-weight-adjusted AEC. No significant difference was observed for objective image noise between the chest CT acquired with the non-weight-adjusted (15.0 ± 3.1) and weight-adjusted (16.1 ± 5.6) AEC techniques (p > 0.05). Conclusion The results of this study suggest that AEC should be tailored according to patient weight. Without weight-based adjustment of AEC, patients are exposed to a 17 - 43% higher radiation-dose from a chest CT. PMID:20046494

Is Weight-Based Adjustment of Automatic Exposure Control Necessary for the Reduction of Chest CT Radiation Dose?

Energy Technology Data Exchange (ETDEWEB)

Prakash, Priyanka; Kalra, Mannudeep K.; Gilman, Matthew D.; Shepard, Jo Anne O.; Digumarthy, Subba R. [Massachusetts General Hospital and Harvard Medical School, Boston (United States)

2010-02-15

To assess the effects of radiation dose reduction in the chest CT using a weight-based adjustment of the automatic exposure control (AEC) technique. With Institutional Review Board Approval, 60 patients (mean age, 59.1 years; M:F = 35:25) and 57 weight-matched patients (mean age, 52.3 years, M:F = 25:32) were scanned using a weight-adjusted AEC and nonweight- adjusted AEC, respectively on a 64-slice multidetector CT with a 0.984:1 pitch, 0.5 second rotation time, 40 mm table feed/rotation, and 2.5 mm section thickness. Patients were categorized into 3 weight categories; < 60 kg (n = 17), 60-90 kg (n = 52), and > 90 kg (n = 48). Patient weights, scanning parameters, CT dose index volumes (CTDIvol) and dose length product (DLP) were recorded, while effective dose (ED) was estimated. Image noise was measured in the descending thoracic aorta. Data were analyzed using a standard statistical package (SAS/STAT) (Version 9.1, SAS institute Inc, Cary, NC). Compared to the non-weight-adjusted AEC, the weight-adjusted AEC technique resulted in an average decrease of 29% in CTDIvol and a 27% effective dose reduction (p < 0.0001). With weight-adjusted AEC, the CTDIvol decreased to 15.8, 15.9, and 27.3 mGy for the < 60, 60-90 and > 91 kg weight groups, respectively, compared to 20.3, 27.9 and 32.8 mGy, with non-weight adjusted AEC. No significant difference was observed for objective image noise between the chest CT acquired with the non-weight-adjusted (15.0 {+-} 3.1) and weight-adjusted (16.1 {+-} 5.6) AEC techniques (p > 0.05). The results of this study suggest that AEC should be tailored according to patient weight. Without weight-based adjustment of AEC, patients are exposed to a 17 - 43% higher radiation-dose from a chest CT.

Lateral topography for reducing effective dose in low-dose chest CT.

Science.gov (United States)

Bang, Dong-Ho; Lim, Daekeon; Hwang, Wi-Sub; Park, Seong-Hoon; Jeong, Ok-man; Kang, Kyung Wook; Kang, Hohyung

2013-06-01

The purposes of this study were to assess radiation exposure during low-dose chest CT by using lateral topography and to compare the lateral topographic findings with findings obtained with anteroposterior topography alone and anteroposterior and lateral topography combined. From November 2011 to February 2012, 210 male subjects were enrolled in the study. Age, weight, and height of the men were recorded. All subjects were placed into one of three subgroups based on the type of topographic image obtained: anteroposterior topography, lateral topography, and both anteroposterior and lateral topography. Imaging was performed with a 128-MDCT scanner. CT, except for topography, was the same for all subjects. A radiologist analyzed each image, recorded scan length, checked for any insufficiencies in the FOV, and calculated the effective radiation dose. One-way analysis of variance and multiple comparisons were used to compare the effective radiation exposure and scan length between groups. The mean scan length in the anteroposterior topography group was significantly greater than that of the lateral topography group and the combined anteroposterior and lateral topography group (p topography group (0.735 ± 0.033 mSv) was significantly lower than that for the anteroposterior topography group (0.763 ± 0.038 mSv) and the combined anteroposterior and lateral topography group (0.773 ± 0.038) (p < 0.001). Lateral topographic low-dose CT was associated with a lower effective radiation dose and scan length than either anteroposterior topographic low-dose chest CT or low-dose chest CT with both anteroposterior and lateral topograms.

Radiation dose reduction in chest CT—Review of available options

International Nuclear Information System (INIS)

Kubo, Takeshi; Ohno, Yoshiharu; Kauczor, Hans Ulrich; Hatabu, Hiroto

2014-01-01

Highlights: • The present status of proliferating CT examinations was presented. • Technical improvements of CT scanners for radiation dose reduction were reviewed. • Advantage and disadvantage of methods for CT radiation dose reduction were discussed. • Evidences for safety of CT radiation dose reduction were reviewed. - Abstract: Computed tomography currently accounts for the majority of radiation exposure related to medical imaging. Although technological improvement of CT scanners has reduced the radiation dose of individual examinations, the benefit was overshadowed by the rapid increase in the number of CT examinations. Radiation exposure from CT examination should be kept as low as reasonably possible for patient safety. Measures to avoid inappropriate CT examinations are needed. Principles and information on radiation dose reduction in chest CT are reviewed in this article. The reduction of tube current and tube potential are the mainstays of dose reduction methods. Study results indicate that routine protocols with reduced tube current are feasible with diagnostic results comparable to conventional standard dose protocols. Tube current adjustment is facilitated by the advent of automatic tube current modulation systems by setting the appropriate image quality level for the purpose of the examination. Tube potential reduction is an effective method for CT pulmonary angiography. Tube potential reduction often requires higher tube current for satisfactory image quality, but may still contribute to significant radiation dose reduction. Use of lower tube potential also has considerable advantage for smaller patients. Improvement in image production, especially the introduction of iterative reconstruction methods, is expected to lower radiation dose significantly. Radiation dose reduction in CT is a multifaceted issue. Understanding these aspects leads to an optimal solution for various indications of chest CT

Radiation dose reduction in chest CT—Review of available options

Energy Technology Data Exchange (ETDEWEB)

Kubo, Takeshi, E-mail: tkubo@kuhpkyoto-u.ac.jp [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507 (Japan); Ohno, Yoshiharu, E-mail: yosirad@kobe-u.ac.jp [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan); Kauczor, Hans Ulrich, E-mail: hu.kauczor@med.uni-heidelberg.de [Diagnostic and Interventional Radiology, University Clinic Heidelberg, Im Neuenheimer Feld 110, D-69120 Heidelberg (Germany); Hatabu, Hiroto, E-mail: hhatabu@partners.org [Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States)

2014-10-15

Highlights: • The present status of proliferating CT examinations was presented. • Technical improvements of CT scanners for radiation dose reduction were reviewed. • Advantage and disadvantage of methods for CT radiation dose reduction were discussed. • Evidences for safety of CT radiation dose reduction were reviewed. - Abstract: Computed tomography currently accounts for the majority of radiation exposure related to medical imaging. Although technological improvement of CT scanners has reduced the radiation dose of individual examinations, the benefit was overshadowed by the rapid increase in the number of CT examinations. Radiation exposure from CT examination should be kept as low as reasonably possible for patient safety. Measures to avoid inappropriate CT examinations are needed. Principles and information on radiation dose reduction in chest CT are reviewed in this article. The reduction of tube current and tube potential are the mainstays of dose reduction methods. Study results indicate that routine protocols with reduced tube current are feasible with diagnostic results comparable to conventional standard dose protocols. Tube current adjustment is facilitated by the advent of automatic tube current modulation systems by setting the appropriate image quality level for the purpose of the examination. Tube potential reduction is an effective method for CT pulmonary angiography. Tube potential reduction often requires higher tube current for satisfactory image quality, but may still contribute to significant radiation dose reduction. Use of lower tube potential also has considerable advantage for smaller patients. Improvement in image production, especially the introduction of iterative reconstruction methods, is expected to lower radiation dose significantly. Radiation dose reduction in CT is a multifaceted issue. Understanding these aspects leads to an optimal solution for various indications of chest CT.

Model-based iterative reconstruction technique for radiation dose reduction in chest CT: comparison with the adaptive statistical iterative reconstruction technique

Energy Technology Data Exchange (ETDEWEB)

Katsura, Masaki; Matsuda, Izuru; Akahane, Masaaki; Sato, Jiro; Akai, Hiroyuki; Yasaka, Koichiro; Kunimatsu, Akira; Ohtomo, Kuni [University of Tokyo, Department of Radiology, Graduate School of Medicine, Bunkyo-ku, Tokyo (Japan)

2012-08-15

To prospectively evaluate dose reduction and image quality characteristics of chest CT reconstructed with model-based iterative reconstruction (MBIR) compared with adaptive statistical iterative reconstruction (ASIR). One hundred patients underwent reference-dose and low-dose unenhanced chest CT with 64-row multidetector CT. Images were reconstructed with 50 % ASIR-filtered back projection blending (ASIR50) for reference-dose CT, and with ASIR50 and MBIR for low-dose CT. Two radiologists assessed the images in a blinded manner for subjective image noise, artefacts and diagnostic acceptability. Objective image noise was measured in the lung parenchyma. Data were analysed using the sign test and pair-wise Student's t-test. Compared with reference-dose CT, there was a 79.0 % decrease in dose-length product with low-dose CT. Low-dose MBIR images had significantly lower objective image noise (16.93 {+-} 3.00) than low-dose ASIR (49.24 {+-} 9.11, P < 0.01) and reference-dose ASIR images (24.93 {+-} 4.65, P < 0.01). Low-dose MBIR images were all diagnostically acceptable. Unique features of low-dose MBIR images included motion artefacts and pixellated blotchy appearances, which did not adversely affect diagnostic acceptability. Diagnostically acceptable chest CT images acquired with nearly 80 % less radiation can be obtained using MBIR. MBIR shows greater potential than ASIR for providing diagnostically acceptable low-dose CT images without severely compromising image quality. (orig.)

Diagnostic Yield of Recommendations for Chest CT Examination Prompted by Outpatient Chest Radiographic Findings

Science.gov (United States)

Harvey, H. Benjamin; Gilman, Matthew D.; Wu, Carol C.; Cushing, Matthew S.; Halpern, Elkan F.; Zhao, Jing; Pandharipande, Pari V.; Shepard, Jo-Anne O.

2015-01-01

Purpose To evaluate the diagnostic yield of recommended chest computed tomography (CT) prompted by abnormalities detected on outpatient chest radiographic images. Materials and Methods This HIPAA-compliant study had institutional review board approval; informed consent was waived. Reports of all outpatient chest radiographic examinations performed at a large academic center during 2008 (n = 29 138) were queried to identify studies that included a recommendation for a chest CT imaging. The radiology information system was queried for these patients to determine if a chest CT examination was obtained within 1 year of the index radiographic examination that contained the recommendation. For chest CT examinations obtained within 1 year of the index chest radiographic examination and that met inclusion criteria, chest CT images were reviewed to determine if there was an abnormality that corresponded to the chest radiographic finding that prompted the recommendation. All corresponding abnormalities were categorized as clinically relevant or not clinically relevant, based on whether further work-up or treatment was warranted. Groups were compared by using t test and Fisher exact test with a Bonferroni correction applied for multiple comparisons. Results There were 4.5% (1316 of 29138 [95% confidence interval {CI}: 4.3%, 4.8%]) of outpatient chest radiographic examinations that contained a recommendation for chest CT examination, and increasing patient age (P recommendation for chest CT examination. Of patients within this subset who met inclusion criteria, 65.4% (691 of 1057 [95% CI: 62.4%, 68.2%) underwent a chest CT examination within the year after the index chest radiographic examination. Clinically relevant corresponding abnormalities were present on chest CT images in 41.4% (286 of 691 [95% CI: 37.7%, 45.2%]) of cases, nonclinically relevant corresponding abnormalities in 20.6% (142 of 691 [95% CI: 17.6%, 23.8%]) of cases, and no corresponding abnormalities in 38

Model-based iterative reconstruction technique for radiation dose reduction in chest CT: comparison with the adaptive statistical iterative reconstruction technique

International Nuclear Information System (INIS)

Katsura, Masaki; Matsuda, Izuru; Akahane, Masaaki; Sato, Jiro; Akai, Hiroyuki; Yasaka, Koichiro; Kunimatsu, Akira; Ohtomo, Kuni

2012-01-01

To prospectively evaluate dose reduction and image quality characteristics of chest CT reconstructed with model-based iterative reconstruction (MBIR) compared with adaptive statistical iterative reconstruction (ASIR). One hundred patients underwent reference-dose and low-dose unenhanced chest CT with 64-row multidetector CT. Images were reconstructed with 50 % ASIR-filtered back projection blending (ASIR50) for reference-dose CT, and with ASIR50 and MBIR for low-dose CT. Two radiologists assessed the images in a blinded manner for subjective image noise, artefacts and diagnostic acceptability. Objective image noise was measured in the lung parenchyma. Data were analysed using the sign test and pair-wise Student's t-test. Compared with reference-dose CT, there was a 79.0 % decrease in dose-length product with low-dose CT. Low-dose MBIR images had significantly lower objective image noise (16.93 ± 3.00) than low-dose ASIR (49.24 ± 9.11, P < 0.01) and reference-dose ASIR images (24.93 ± 4.65, P < 0.01). Low-dose MBIR images were all diagnostically acceptable. Unique features of low-dose MBIR images included motion artefacts and pixellated blotchy appearances, which did not adversely affect diagnostic acceptability. Diagnostically acceptable chest CT images acquired with nearly 80 % less radiation can be obtained using MBIR. MBIR shows greater potential than ASIR for providing diagnostically acceptable low-dose CT images without severely compromising image quality. (orig.)

Radiation dose levels in pediatric chest CT: experience in 499 children evaluated with dual-source single-energy CT

Energy Technology Data Exchange (ETDEWEB)

Martine, Remy-Jardin; Colas, Lucie; Jean-Baptiste, Faivre; Remy, Jacques [CHU Lille (EA 2694) University of Lille, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Santangelo, Teresa [CHU Lille (EA 2694) University of Lille, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Bambino Gesu Children' s Hospital, Department of Imaging, Rome (Italy); Duhamel, Alain [University of Lille (EA 2694), Department of Biostatistics, CHU Lille, Lille (France); Deschildre, Antoine [CHU Lille - University of Lille, Department of Pediatric Pulmonology, Lille (France)

2017-02-15

The availability of dual-source technology has introduced the possibility of scanning children at lower kVp with a high-pitch mode, combining high-speed data acquisition and high temporal resolution. To establish the radiation dose levels of dual-source, single-energy chest CT examinations in children. We retrospectively recorded the dose-length product (DLP) of 499 consecutive examinations obtained in children <50 kg, divided into five weight groups: group 1 (<10 kg, n = 129); group 2 (10-20 kg, n = 176); group 3 (20-30 kg, n = 99), group 4 (30-40 kg, n = 58) and group 5 (40-49 kg, n = 37). All CT examinations were performed with high temporal resolution (75 ms), a high-pitch mode and a weight-adapted selection of the milliamperage. CT examinations were obtained at 80 kVp with a milliamperage ranging between 40 mAs and 90 mAs, and a pitch of 2.0 (n = 162; 32.5%) or 3.0 (n = 337; 67.5%). The mean duration of data acquisition was 522.8 ± 192.0 ms (interquartile range 390 to 610; median 490). In the study population, the mean CT dose index volume (CTDIvol{sub 32}) was 0.83 mGy (standard deviation [SD] 0.20 mGy; interquartile range 0.72 to 0.94; median 0.78); the mean DLP{sub 32} was 21.4 mGy.cm (SD 9.1 mGy.cm; interquartile range 15 to 25; median 19.0); and the mean size-specific dose estimate (SSDE) was 1.7 mGy (SD 0.4 mGy; interquartile range 1.5 to 1.9; median 1.7). The DLP{sub 32}, CTDI{sub vol32} and SSDE were found to be statistically significant in the five weight categories (P < 0.0001). This study establishes the radiation dose levels for dual-source, single-kVp chest CT from a single center. In the five weight categories, the median values varied 15-37 mGy.cm for the DLP{sub 32}, 0.78-1.25 mGy for the CTDI{sub vol32} and 1.6-2.1 mGy for the SSDE. (orig.)

Radiation dose levels in pediatric chest CT: experience in 499 children evaluated with dual-source single-energy CT

International Nuclear Information System (INIS)

Martine, Remy-Jardin; Colas, Lucie; Jean-Baptiste, Faivre; Remy, Jacques; Santangelo, Teresa; Duhamel, Alain; Deschildre, Antoine

2017-01-01

The availability of dual-source technology has introduced the possibility of scanning children at lower kVp with a high-pitch mode, combining high-speed data acquisition and high temporal resolution. To establish the radiation dose levels of dual-source, single-energy chest CT examinations in children. We retrospectively recorded the dose-length product (DLP) of 499 consecutive examinations obtained in children <50 kg, divided into five weight groups: group 1 (<10 kg, n = 129); group 2 (10-20 kg, n = 176); group 3 (20-30 kg, n = 99), group 4 (30-40 kg, n = 58) and group 5 (40-49 kg, n = 37). All CT examinations were performed with high temporal resolution (75 ms), a high-pitch mode and a weight-adapted selection of the milliamperage. CT examinations were obtained at 80 kVp with a milliamperage ranging between 40 mAs and 90 mAs, and a pitch of 2.0 (n = 162; 32.5%) or 3.0 (n = 337; 67.5%). The mean duration of data acquisition was 522.8 ± 192.0 ms (interquartile range 390 to 610; median 490). In the study population, the mean CT dose index volume (CTDIvol 32 ) was 0.83 mGy (standard deviation [SD] 0.20 mGy; interquartile range 0.72 to 0.94; median 0.78); the mean DLP 32 was 21.4 mGy.cm (SD 9.1 mGy.cm; interquartile range 15 to 25; median 19.0); and the mean size-specific dose estimate (SSDE) was 1.7 mGy (SD 0.4 mGy; interquartile range 1.5 to 1.9; median 1.7). The DLP 32 , CTDI vol32 and SSDE were found to be statistically significant in the five weight categories (P < 0.0001). This study establishes the radiation dose levels for dual-source, single-kVp chest CT from a single center. In the five weight categories, the median values varied 15-37 mGy.cm for the DLP 32 , 0.78-1.25 mGy for the CTDI vol32 and 1.6-2.1 mGy for the SSDE. (orig.)

CT of blunt chest trauma in children

International Nuclear Information System (INIS)

Manson, D.; Babyn, P.S.; Palder, S.; Bergmann, K.

1993-01-01

While trauma is still the leading cause of death in the pediatric age range, it is surprising how little the CT appearances of pediatric chest injury have been investigated in the literature. We have reviewed the CT findings of blunt chest trauma in 44 children for whom chest CT examinations were requested to investigate the extent of intrathoracic injury. We noted a propensity for pulmonary contusions to be located posteriorly or posteromedially, and for them to be anatomically nonsegmental and crescentic in shape. This is possibly attributable to the relatively compliant anterior chest wall in children. The CT appearances of other major thoracic injuries are described, including pulmonary lacerations, pneumothoraces, malpositioned chest tubes, mediastinal hematomas, aortic injury, tracheobronchial injury, hemopericardium, and spinal injuries with paraspinal fluid collections. Children demonstrating findings incidental to the actual injury yet important to the subsequent therapy are also presented. We conclude that, in the event of clinically significant blunt chest trauma, the single supine chest examination in the trauma room is insufficient to adequately identify the extent of intrathoracic injury. With the exception of concern for aortic injury for which aortography is indicated, a dynamically enhanced CT scan of the thorax should be performed as clinically significant findings may result in altered therapy. (orig.)

Low-dosage helical CT applications for chest medical checkup and lung cancer screening

International Nuclear Information System (INIS)

Wang Ping; Cui Fa; Liang Huanqing; Zheng Minfei

2005-01-01

Objective: A discussion on low-dosage helical CT applications on chest medical checkup and lung cancer screening. Methods: On the 100 chest medical check up with three different of protocols, including standard-dosage (the tube current was 230 mAs) were compared with low-dose (tube current was 50 mAs or 30 mAs). Results: Low-dosage helical CT scan provides excellent images. In 100 chest medical checkup, 39 nodules or masses were revealed, enlarged lymph node was noted in 1 case; emphysema or bullae was demonstrated in 3 segments; thickening of bronchial wall was shown in 2 cases; and localized pleural thickening was found in 1 case. Conclusion: In chest checkup or lung cancer screening low-dosage helical CT (tube current 30 mAs) will not only guarantee image quality but also reduce the radiation dose during the examination. (authors)

Radiation dose reduction with the adaptive statistical iterative reconstruction (ASIR) technique for chest CT in children: An intra-individual comparison

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung Hyun, E-mail: circle1128@yuhs.ac [Department of Radiology and Research Institute of Radiological Science, Severance Children' s Hospital, Yonsei University, College of Medicine, Seoul (Korea, Republic of); Kim, Myung-Joon, E-mail: mjkim@yuhs.ac [Department of Radiology and Research Institute of Radiological Science, Severance Children' s Hospital, Yonsei University, College of Medicine, Seoul (Korea, Republic of); Yoon, Choon-Sik, E-mail: yooncs58@yuhs.ac [Department of Radiology, Gangnam Severance Hospital, Yonsei University, College of Medicine, Seoul (Korea, Republic of); Lee, Mi-Jung, E-mail: mjl1213@yuhs.ac [Department of Radiology and Research Institute of Radiological Science, Severance Children' s Hospital, Yonsei University, College of Medicine, Seoul (Korea, Republic of)

2012-09-15

Objective: To retrospectively compare radiation dose and image quality of pediatric chest CT using a routine dose protocol reconstructed with filtered back projection (FBP) (the Routine study) and a low-dose protocol with 50% adaptive statistical iterative reconstruction (ASIR) (the ASIR study). Materials and methods: We retrospectively reviewed chest CT performed in pediatric patients who underwent both the Routine study and the ASIR study on different days between January 2010 and August 2011. Volume CT dose indices (CTDIvol), dose length products (DLP), and effective doses were obtained to estimate radiation dose. The image quality was evaluated objectively as noise measured in the descending aorta and paraspinal muscle, and subjectively by three radiologists for noise, sharpness, artifacts, and diagnostic acceptability using a four-point scale. The paired Student's t-test and the Wilcoxon signed-rank test were used for statistical analysis. Results: Twenty-six patients (M:F = 13:13, mean age 11.7) were enrolled. The ASIR studies showed 60.3%, 56.2%, and 55.2% reductions in CTDIvol (from 18.73 to 7.43 mGy, P < 0.001), DLP (from 307.42 to 134.51 mGy × cm, P < 0.001), and effective dose (from 4.12 to 1.84 mSv, P < 0.001), respectively, compared with the Routine studies. The objective noise was higher in the paraspinal muscle of the ASIR studies (20.81 vs. 16.67, P = 0.004), but was not different in the aorta (18.23 vs. 18.72, P = 0.726). The subjective image quality demonstrated no difference between the two studies. Conclusion: A low-dose protocol with 50% ASIR allows radiation dose reduction in pediatric chest CT by more than 55% while maintaining image quality.

Radiation dose reduction with the adaptive statistical iterative reconstruction (ASIR) technique for chest CT in children: An intra-individual comparison

International Nuclear Information System (INIS)

Lee, Seung Hyun; Kim, Myung-Joon; Yoon, Choon-Sik; Lee, Mi-Jung

2012-01-01

Objective: To retrospectively compare radiation dose and image quality of pediatric chest CT using a routine dose protocol reconstructed with filtered back projection (FBP) (the Routine study) and a low-dose protocol with 50% adaptive statistical iterative reconstruction (ASIR) (the ASIR study). Materials and methods: We retrospectively reviewed chest CT performed in pediatric patients who underwent both the Routine study and the ASIR study on different days between January 2010 and August 2011. Volume CT dose indices (CTDIvol), dose length products (DLP), and effective doses were obtained to estimate radiation dose. The image quality was evaluated objectively as noise measured in the descending aorta and paraspinal muscle, and subjectively by three radiologists for noise, sharpness, artifacts, and diagnostic acceptability using a four-point scale. The paired Student's t-test and the Wilcoxon signed-rank test were used for statistical analysis. Results: Twenty-six patients (M:F = 13:13, mean age 11.7) were enrolled. The ASIR studies showed 60.3%, 56.2%, and 55.2% reductions in CTDIvol (from 18.73 to 7.43 mGy, P < 0.001), DLP (from 307.42 to 134.51 mGy × cm, P < 0.001), and effective dose (from 4.12 to 1.84 mSv, P < 0.001), respectively, compared with the Routine studies. The objective noise was higher in the paraspinal muscle of the ASIR studies (20.81 vs. 16.67, P = 0.004), but was not different in the aorta (18.23 vs. 18.72, P = 0.726). The subjective image quality demonstrated no difference between the two studies. Conclusion: A low-dose protocol with 50% ASIR allows radiation dose reduction in pediatric chest CT by more than 55% while maintaining image quality

Chest tube placement in thorax trauma - comparison chest X-ray and computed tomography (CT)

International Nuclear Information System (INIS)

Heim, P.; Maas, R.; Buecheler, E.; Tesch, C.

1998-01-01

Estimation of chest tube placement in patients with thoracic trauma with regard to chest tube malposition in chest radiography in the supine position compared to additional computed tomography of the thorax. Material and methods: Apart from compulsory chest radiography after one or multiple chest tube insertions, 31 severely injured patients with thoracic trauma underwent a CT scan of the thorax. These 31 patients with 40 chest tubes constituted the basis for the present analysis. Results: In chest radiography in the supine position there were no chest tube malpositions (n=40); In the CT scans 25 correct positions, 7 pseudo-malpositions, 6 intrafissural and 2 intrapulmonary malpositions were identified. Moreover 16 sufficient, 18 insufficient and 6 indifferent functions of the chest tubes were seen. Conclusion: In case of lasting clinical problems and questionable function of the chest tube, chest radiography should be supplemented by a CT scan of the thorax in order to estimate the position of the chest tube. (orig.) [de

Estimation of the radiation exposure of a chest pain protocol with ECG-gating in dual-source computed tomography

International Nuclear Information System (INIS)

Ketelsen, Dominik; Luetkhoff, Marie H.; Thomas, Christoph; Werner, Matthias; Tsiflikas, Ilias; Reimann, Anja; Kopp, Andreas F.; Claussen, Claus D.; Heuschmid, Martin; Buchgeister, Markus; Burgstahler, Christof

2009-01-01

The aim of the study was to evaluate radiation exposure of a chest pain protocol with ECG-gated dual-source computed tomography (DSCT). An Alderson Rando phantom equipped with thermoluminescent dosimeters was used for dose measurements. Exposure was performed on a dual-source computed tomography system with a standard protocol for chest pain evaluation (120 kV, 320 mAs/rot) with different simulated heart rates (HRs). The dose of a standard chest CT examination (120 kV, 160 mAs) was also measured. Effective dose of the chest pain protocol was 19.3/21.9 mSv (male/female, HR 60), 17.9/20.4 mSv (male/female, HR 80) and 14.7/16.7 mSv (male/female, HR 100). Effective dose of a standard chest examination was 6.3 mSv (males) and 7.2 mSv (females). Radiation dose of the chest pain protocol increases significantly with a lower heart rate for both males (p = 0.040) and females (p = 0.044). The average radiation dose of a standard chest CT examination is about 36.5% that of a CT examination performed for chest pain. Using DSCT, the evaluated chest pain protocol revealed a higher radiation exposure compared with standard chest CT. Furthermore, HRs markedly influenced the dose exposure when using the ECG-gated chest pain protocol. (orig.)

Image quality in children with low-radiation chest CT using adaptive statistical iterative reconstruction and model-based iterative reconstruction.

Directory of Open Access Journals (Sweden)

Jihang Sun

Full Text Available OBJECTIVE: To evaluate noise reduction and image quality improvement in low-radiation dose chest CT images in children using adaptive statistical iterative reconstruction (ASIR and a full model-based iterative reconstruction (MBIR algorithm. METHODS: Forty-five children (age ranging from 28 days to 6 years, median of 1.8 years who received low-dose chest CT scans were included. Age-dependent noise index (NI was used for acquisition. Images were retrospectively reconstructed using three methods: MBIR, 60% of ASIR and 40% of conventional filtered back-projection (FBP, and FBP. The subjective quality of the images was independently evaluated by two radiologists. Objective noises in the left ventricle (LV, muscle, fat, descending aorta and lung field at the layer with the largest cross-section area of LV were measured, with the region of interest about one fourth to half of the area of descending aorta. Optimized signal-to-noise ratio (SNR was calculated. RESULT: In terms of subjective quality, MBIR images were significantly better than ASIR and FBP in image noise and visibility of tiny structures, but blurred edges were observed. In terms of objective noise, MBIR and ASIR reconstruction decreased the image noise by 55.2% and 31.8%, respectively, for LV compared with FBP. Similarly, MBIR and ASIR reconstruction increased the SNR by 124.0% and 46.2%, respectively, compared with FBP. CONCLUSION: Compared with FBP and ASIR, overall image quality and noise reduction were significantly improved by MBIR. MBIR image could reconstruct eligible chest CT images in children with lower radiation dose.

Radiation exposure during CT-guided biopsies: recent CT machines provide markedly lower doses.

Science.gov (United States)

Guberina, Nika; Forsting, Michael; Ringelstein, Adrian; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Theysohn, Jens; Wetter, Axel

2018-03-28

To examine radiation dose levels of CT-guided interventional procedures of chest, abdomen, spine and extremities on different CT-scanner generations at a large multicentre institute. 1,219 CT-guided interventional biopsies of different organ regions ((A) abdomen (n=516), (B) chest (n=528), (C) spine (n=134) and (D) extremities (n=41)) on different CT-scanners ((I) SOMATOM-Definition-AS+, (II) Volume-Zoom, (III) Emotion6) were included from 2013-2016. Important CT-parameters and standard dose-descriptors were retrospectively examined. Additionally, effective dose and organ doses were calculated using Monte-Carlo simulation, following ICRP103. Overall, radiation doses for CT interventions are highly dependent on CT-scanner generation: the newer the CT scanner, the lower the radiation dose imparted to patients. Mean effective doses for each of four procedures on available scanners are: (A) (I) 9.3mSv versus (II) 13.9mSv (B) (I) 7.3mSv versus (III) 11.4mSv (C) (I) 6.3mSv versus (II) 7.4mSv (D) (I) 4.3mSv versus (II) 10.8mSv. Standard dose descriptors [standard deviation (SD); CT dose index vol (CTDI vol ); dose-length product (DLP body ); size-specific dose estimate (SSDE)] were also compared. Effective dose, organ doses and SSDE for various CT-guided interventional biopsies on different CT-scanner generations following recommendations of the ICRP103 are provided. New CT-scanner generations involve markedly lower radiation doses versus older devices. • Effective dose, organ dose and SSDE are provided for CT-guided interventional examinations. • These data allow identifying organs at risk of higher radiation dose. • Detailed knowledge of radiation dose may contribute to a better individual risk-stratification. • New CT-scanner generations involve markedly lower radiation doses compared to older devices.

Protocol optimization in chest CT scans of child

Energy Technology Data Exchange (ETDEWEB)

Abrao L, L. T.; Amaral de O, F.; Prata M, A. [Biomedical Engineering Center, Centro Federal de Educacao Tecnologica de Minas Gerais, 30421-169, Belo Horizonte, Minas Gerais (Brazil); Bustos F, M., E-mail: luanaabrao@gmail.com [Universidad Federal de Minas Gerais, Department of Nuclear Engineering, Av. Pres. Antonio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

2017-10-15

The dissemination of Computed Tomography (CT), a radiodiagnostic technique, has significant increase in the patient dose. In the last years, this technique has shown a high growth due to clinical cases of medical emergencies, neoplasm and pediatric traumas. Dose measurement is important to correlate with the deleterious effects of radiation on the organism and radiation future effects is related with stochastic risks due to tissue radiosensitivity, allied to the life expectancy of the child. In this work, a cylindrical phantom, representing an adult chest made of polymethylmethacrylate (PMMA), was used and a new born chest phantom with a shape oblong was developed based on the dimensions of a typical newborn. In a Ge CT scanner, Discovery model, with 64 channels, the central slice of the phantoms were irradiated successively in order to obtain dose measurements using an ionizing pencil camera. Based in the measurements, dose index was calculated (CTDI{sub vol}). The radiological service chest protocol using a voltage of 120 kV was used for scanning 10 cm of the central area of the adult and newborn phantom, in helical mode. An acquisition of images was performed using this radiological service chest protocol to compare with the protocol optimized. In the newborn phantom was also used protocols optimized using a voltage of 120 and 80 kV. The voltage of 80 kV has the lowest dose index for the pediatric object phantom. This work allowed the comparison between absorbed dose variations by the pediatric phantom changing the X-ray tube supply voltage. This dose variation has shown how important is specific protocols for children. (Author)

Protocol optimization in chest CT scans of child

International Nuclear Information System (INIS)

Abrao L, L. T.; Amaral de O, F.; Prata M, A.; Bustos F, M.

2017-10-01

The dissemination of Computed Tomography (CT), a radiodiagnostic technique, has significant increase in the patient dose. In the last years, this technique has shown a high growth due to clinical cases of medical emergencies, neoplasm and pediatric traumas. Dose measurement is important to correlate with the deleterious effects of radiation on the organism and radiation future effects is related with stochastic risks due to tissue radiosensitivity, allied to the life expectancy of the child. In this work, a cylindrical phantom, representing an adult chest made of polymethylmethacrylate (PMMA), was used and a new born chest phantom with a shape oblong was developed based on the dimensions of a typical newborn. In a Ge CT scanner, Discovery model, with 64 channels, the central slice of the phantoms were irradiated successively in order to obtain dose measurements using an ionizing pencil camera. Based in the measurements, dose index was calculated (CTDI vol ). The radiological service chest protocol using a voltage of 120 kV was used for scanning 10 cm of the central area of the adult and newborn phantom, in helical mode. An acquisition of images was performed using this radiological service chest protocol to compare with the protocol optimized. In the newborn phantom was also used protocols optimized using a voltage of 120 and 80 kV. The voltage of 80 kV has the lowest dose index for the pediatric object phantom. This work allowed the comparison between absorbed dose variations by the pediatric phantom changing the X-ray tube supply voltage. This dose variation has shown how important is specific protocols for children. (Author)

Reduced-dose chest CT with 3D automatic exposure control vs. standard chest CT: Quantitative assessment of emphysematous changes in smokers’ lung parenchyma

International Nuclear Information System (INIS)

Koyama, Hisanobu; Ohno, Yoshiharu; Yamazaki, Youichi; Matsumoto, Keiko; Onishi, Yumiko; Takenaka, Daisuke; Yoshikawa, Takeshi; Nishio, Mizuho; Matsumoto, Sumiaki; Murase, Kenya; Nishimura, Yoshihiro

2012-01-01

Objectives: To determine the capability of reduced-dose chest CT with three-dimensional (3D) automatic exposure control (AEC) on quantitative assessment of emphysematous change in smoker’ lung parenchyma, compared to standard chest CT. Methods: Twenty consecutive smoker patients (mean age 62.8 years) underwent CT examinations using a standard protocol (150 mAs) and a protocol with 3D-AEC. In this study, the targeted standard deviations number was set to 160. For quantitative assessment of emphysematous change in lung parenchyma in each subject using the standard protocol, a percentage of voxels less than −950 HU in the lung (%LAA −950 ) was calculated. The 3D-AEC protocol's %LAA was computed from of voxel percentages under selected threshold CT value. The differences of radiation doses between these two protocols were evaluated, and %LAAs −950 was compared with the 3D-AEC protocol %LAAs. Results: Mean dose length products were 780.2 ± 145.5 mGy cm (standard protocol), and 192.0 ± 95.9 (3D-AEC protocol). There was significant difference between them (paired Student's t test, p −950 and 3D-AEC protocol %LAAs. In adopting the feasible threshold CT values of the 3D-AEC protocol, the 3D-AEC protocol %LAAs were significantly correlated with %LAAs −950 (r = 0.98, p < 0.001) and limits of agreement from Bland–Altman analysis was 0.52 ± 4.3%. Conclusions: Changing threshold CT values demonstrated that reduced-dose chest CT with 3D-AEC can substitute for the standard protocol in assessments of emphysematous change in smoker’ lung parenchyma.

Radiation risk index for pediatric CT. A patient-derived metric

International Nuclear Information System (INIS)

Samei, Ehsan; Tian, Xiaoyu; Paul Segars, W.; Frush, Donald P.

2017-01-01

There is a benefit in characterizing radiation-induced cancer risk in pediatric chest and abdominopelvic CT: a singular metric that represents the whole-body radiation burden while also accounting for age, gender and organ sensitivity. To compute an index of radiation risk for pediatric chest and abdominopelvic CT. Using a protocol approved by our institutional review board, 42 pediatric patients (age: 0-16 years, weight: 2-80 kg) were modeled into virtual whole-body anatomical models. Organ doses were estimated for clinical chest and abdominopelvic CT examinations of the patients using validated Monte Carlo simulations of two major scanner models. Using age-, size- and gender-specific organ risk coefficients, the values were converted to normalized effective dose (by dose length product) (denoted as the k factor) and a normalized risk index (denoted as the q factor). An analysis was performed to determine how these factors are correlated with patient age and size for both males and females to provide a strategy to better characterize individualized risk. The k factor was found to be exponentially correlated with the average patient diameter. For both genders, the q factor also exhibited an exponential relationship with both the average patient diameter and with patient age. For both factors, the differences between the scanner models were less than 8%. The study defines a whole-body radiation risk index for chest and abdominopelvic CT imaging, that incorporates individual estimated organ dose values, organ radiation sensitivity, patient size, exposure age and patient gender. This indexing metrology enables the assessment and potential improvement of chest and abdominopelvic CT performance through surveillance of practice dose profiles across patients and may afford improved informed communication. (orig.)

Radiation risk index for pediatric CT. A patient-derived metric

Energy Technology Data Exchange (ETDEWEB)

Samei, Ehsan [Duke University Medical Center, Department of Radiology, Carl E. Ravin Advanced Imaging Laboratories, Durham, NC (United States); Duke University Medical Center, Department of Biomedical Engineering, Electrical and Computer Engineering, Durham, NC (United States); Duke University Medical Center, Medical Physics Graduate Program, Durham, NC (United States); Tian, Xiaoyu [Duke University Medical Center, Department of Radiology, Carl E. Ravin Advanced Imaging Laboratories, Durham, NC (United States); Paul Segars, W. [Duke University Medical Center, Department of Radiology, Carl E. Ravin Advanced Imaging Laboratories, Durham, NC (United States); Duke University Medical Center, Medical Physics Graduate Program, Durham, NC (United States); Frush, Donald P. [Duke University Medical Center, Medical Physics Graduate Program, Durham, NC (United States); Duke University Medical Center, Division of Pediatric Radiology, Department of Radiology, Durham, NC (United States)

2017-12-15

There is a benefit in characterizing radiation-induced cancer risk in pediatric chest and abdominopelvic CT: a singular metric that represents the whole-body radiation burden while also accounting for age, gender and organ sensitivity. To compute an index of radiation risk for pediatric chest and abdominopelvic CT. Using a protocol approved by our institutional review board, 42 pediatric patients (age: 0-16 years, weight: 2-80 kg) were modeled into virtual whole-body anatomical models. Organ doses were estimated for clinical chest and abdominopelvic CT examinations of the patients using validated Monte Carlo simulations of two major scanner models. Using age-, size- and gender-specific organ risk coefficients, the values were converted to normalized effective dose (by dose length product) (denoted as the k factor) and a normalized risk index (denoted as the q factor). An analysis was performed to determine how these factors are correlated with patient age and size for both males and females to provide a strategy to better characterize individualized risk. The k factor was found to be exponentially correlated with the average patient diameter. For both genders, the q factor also exhibited an exponential relationship with both the average patient diameter and with patient age. For both factors, the differences between the scanner models were less than 8%. The study defines a whole-body radiation risk index for chest and abdominopelvic CT imaging, that incorporates individual estimated organ dose values, organ radiation sensitivity, patient size, exposure age and patient gender. This indexing metrology enables the assessment and potential improvement of chest and abdominopelvic CT performance through surveillance of practice dose profiles across patients and may afford improved informed communication. (orig.)

Clinical Utility of Chest Computed Tomography in Patients with Rib Fractures CT Chest and Rib Fractures.

Science.gov (United States)

Chapman, Brandon C; Overbey, Douglas M; Tesfalidet, Feven; Schramm, Kristofer; Stovall, Robert T; French, Andrew; Johnson, Jeffrey L; Burlew, Clay C; Barnett, Carlton; Moore, Ernest E; Pieracci, Fredric M

2016-12-01

Chest CT is more sensitive than a chest X-ray (CXR) in diagnosing rib fractures; however, the clinical significance of these fractures remains unclear. The purpose of this study was to determine the added diagnostic use of chest CT performed after CXR in patients with either known or suspected rib fractures secondary to blunt trauma. Retrospective cohort study of blunt trauma patients with rib fractures at a level I trauma center that had both a CXR and a CT chest. The CT finding of ≥ 3 additional fractures in patients with ≤ 3 rib fractures on CXR was considered clinically meaningful. Student's t-test and chi-square analysis were used for comparison. We identified 499 patients with rib fractures: 93 (18.6%) had CXR only, 7 (1.4%) had chest CT only, and 399 (79.9%) had both CXR and chest CT. Among these 399 patients, a total of 1,969 rib fractures were identified: 1,467 (74.5%) were missed by CXR. The median number of additional fractures identified by CT was 3 (range, 4 - 15). Of 212 (53.1%) patients with a clinically meaningful increase in the number of fractures, 68 patients underwent one or more clinical interventions: 36 SICU admissions, 20 pain catheter placements, 23 epidural placements, and 3 SSRF. Additionally, 70 patients had a chest tube placed for retained hemothorax or occult pneumothorax. Overall, 138 patients (34.5%) had a change in clinical management based upon CT chest. The chest X-ray missed ~75% of rib fractures seen on chest CT. Although patients with a clinical meaningful increase in the number of rib fractures were more likely to be admitted to the intensive care unit, there was no associated improvement in pulmonary outcomes.

Spiral CT for evaluation of chest trauma

International Nuclear Information System (INIS)

Roehnert, W.; Weise, R.

1997-01-01

After implementation of spiral CT in our department, we carried out an analysis for determining anew the value of CT as a modality of chest trauma diagnosis in the emergency department. The retrospective study covers a period of 10 months and all emergency patients with chest trauma exmined by spiral CT. The major lesions of varying seriousness covered by this study are: pneumothorax, hematothorax, pulmonary contusion or laceration, mediastinal hematoma, rupture of a vessel, injury of the heart and pericardium. The various fractures are not included in this study. In many cases, spiral CT within relatively short time yields significant diagnostic findings, frequently saving additional angiography. A rigid diagnostic procedure cannot be formulated. Plain-film chest radiography still remains a diagnostic modality of high value. (Orig.) [de

The role of CT in assessing chest pain

International Nuclear Information System (INIS)

Capsa, R.

2012-01-01

Full text: Objective: Thoracic pain represents the common feature of a wide range of diseases of different causes. Usually, chest pain requires a fast workup, in order to eliminate potentially hazardous underlying conditions. The objective of the paper consists of presenting the role of computerized tomography (CT) in assessing the different causes and conditions related to chest pain. Materials and methods: The educational presentation relies on current literature data and mostly on images obtained from patients admitted in the various clinics and departments of our hospital, suffering from chest pain as admittance condition or as a symptom appeared during the hospital stay. Results: There are various radiological and imaging options for assessing a patient with chest pain, with reference to the underlying condition, type of pain onset (acute or chronic), specific indications and contraindications. From all these, CT is considered one of the most useful imaging options, in terms of diagnosis accuracy, fast workup, cost and availability. This paper focuses on the role of CT, presenting the most important diseases and conditions related to potential occurrence of chest pain and the most specific CT signs and findings usually reported in this setting. Furthermore, the presentation separates acute and chronic conditions, presenting the actual imaging protocols employed in this circumstances. Finally, there are considerations regarding CT rule-out protocols used in patients with acute chest pain in emergency conditions. Conclusions: Fast and accurate diagnosis is crucial for patient outcome, often life-saving, but currently there is no single algorithm in the imaging assessment of chest pain, while choosing the best imaging option relies mainly on history, clinical and laboratory data. CT is one of the most important imaging options available in patients with both acute and chronic chest pain. CT rule-out techniques have still to establish their clear role in a

Evaluation of the image quality of chest CT scans: a phantom study

Energy Technology Data Exchange (ETDEWEB)

Martins N, P. I.; Prata M, A., E-mail: priscillainglid@gmail.com [Centro Federal de Educacao Tecnologica de Minas Gerais, Centro de Engenharia Biomedica, Av. Amazonas 5253, 30421-169 Nova Suica, Belo Horizonte, Minas Gerais (Brazil)

2016-10-15

Computed tomography (CT) is considered one of the most important methods of medical imaging employed nowadays, due to its non-invasiveness and the high quality of the images it is able to generate. However, the diagnostic radiation dose received by an individual over the year often exceeds the dose received on account of background radiation. Therefore, it is important to know and to control the dose distribution in the patient by varying the image acquisition parameters. The aim of this study is to evaluate the variation of the image quality of chest CT scans performed by two phantoms. In this paper, a cylindrical Polymethyl Methacrylate (PMMA) chest phantom was used and a second PMMA phantom has been developed with the same volume but an oblong shape, based on the actual dimensions of a male human thorax, in the axillary region. Ten-centimeter scans of the central area of each phantom were performed by a 16-channel Toshiba CT scanner, model Alexion. The scanning protocol employed was the radiology service protocol for chest scans. The noise survey was conducted within the image of the center slice, in five regions: one central and four peripheral areas close to the edge of the object (anterior, posterior, left and right). The recorded values showed that the oblong phantom, with a shape that is more similar to the actual human chest, has a considerably smaller noise, especially in the anterior, posterior and central regions. (Author)

Evaluation of the image quality of chest CT scans: a phantom study

International Nuclear Information System (INIS)

Martins N, P. I.; Prata M, A.

2016-10-01

Computed tomography (CT) is considered one of the most important methods of medical imaging employed nowadays, due to its non-invasiveness and the high quality of the images it is able to generate. However, the diagnostic radiation dose received by an individual over the year often exceeds the dose received on account of background radiation. Therefore, it is important to know and to control the dose distribution in the patient by varying the image acquisition parameters. The aim of this study is to evaluate the variation of the image quality of chest CT scans performed by two phantoms. In this paper, a cylindrical Polymethyl Methacrylate (PMMA) chest phantom was used and a second PMMA phantom has been developed with the same volume but an oblong shape, based on the actual dimensions of a male human thorax, in the axillary region. Ten-centimeter scans of the central area of each phantom were performed by a 16-channel Toshiba CT scanner, model Alexion. The scanning protocol employed was the radiology service protocol for chest scans. The noise survey was conducted within the image of the center slice, in five regions: one central and four peripheral areas close to the edge of the object (anterior, posterior, left and right). The recorded values showed that the oblong phantom, with a shape that is more similar to the actual human chest, has a considerably smaller noise, especially in the anterior, posterior and central regions. (Author)

Evaluation of the efficiency of bismuth breast shield in CT chest paediatric examinations

International Nuclear Information System (INIS)

Sevillano, D.; Espana, M. L.; Castro, P.; Minguez, C.; Albi, G.; Garcia, E.; Lopez Franco, P.

2006-01-01

The aim of this study is to evaluate the efficiency of bismuth breast shield in CT chest paediatric examinations when automatic exposure control techniques are used. The influence in the radiation dose and the image quality has been evaluated with and without the breast shield in the scoutview. In addition the radiation dose in shielded and non-shielded areas has been compared. Measurements were made in a 16 cm diameter cylindrical PMMA phantom simulating a newborn, and older children were simulated controlling the maximum intensities allowed by the automatic exposure control system AutomA. The highest dose reduction (59%) was obtained with AutomA system and when the breast shield is not used in the scoutview. This reduction in the radiation dose does not mean a significant increase of noise level. The use of the breast shield in the scoutview yielded an increase in the radiation dose in non-shielded areas. The use of bismuth breast shield is recommended only after the scoutview in order to optimise the radiation dose in CT chest paediatric examination when using automatic exposure control AutomA. (Author)

Unilateral Hemithorax Opacification on Chest Radiograph : Comparison of Diagnostic Accuracy of Chest Ultrasonography with CT

Energy Technology Data Exchange (ETDEWEB)

Namkung, Sook; Lee, Kyung Soo; Kwon, O Jung [Samsung Medical Center, Seoul (Korea, Republic of); Chung, Seung Eun [Sangkye Paek Hospital, Seoul (Korea, Republic of)

1996-12-15

To compare the diagnostic accuracy of chest ultrasonography (US) with computed tomography (CT) inpatients with opacification more than one third of unilateral hemithorax on chest radiograph (CXR). Chest US and CT scans from 41 consecutive patients with opacification more than one third of unilateral hemithorax on CXR were prospectively evaluated by two independent radiologists. Each radiologist recorded 1) the nature of pleural effusion (transudate vs. exudate), 2) presence or absence of pulmonary lesion, 3) the characteristic of pulmonary lesion (consolidation or atelectasis and tumor), and 4) presence of solid pleural tumor. The diagnostic accuracy of chest US was compared with CT scan in patients with pleural, pulmonary or other disease. In 32 patients with pleural effusion, differentiation between transudate and exudate was feasible in 27 (84%) patients with US and 26 (81%) patients with CT. In 32 patients with pulmonary and other pleural diseases, sensitivity, specificity and accuracy of US in lesion detection were 86%, 75% and 83% respectively when CT was regarded as a diagnostic gold standard. The diagnostic accuracy of chest US is comparable to CT in patients with hemithorax opacification on CXR

Unilateral Hemithorax Opacification on Chest Radiograph : Comparison of Diagnostic Accuracy of Chest Ultrasonography with CT

International Nuclear Information System (INIS)

Namkung, Sook; Lee, Kyung Soo; Kwon, O Jung; Chung, Seung Eun

1996-01-01

To compare the diagnostic accuracy of chest ultrasonography (US) with computed tomography (CT) inpatients with opacification more than one third of unilateral hemithorax on chest radiograph (CXR). Chest US and CT scans from 41 consecutive patients with opacification more than one third of unilateral hemithorax on CXR were prospectively evaluated by two independent radiologists. Each radiologist recorded 1) the nature of pleural effusion (transudate vs. exudate), 2) presence or absence of pulmonary lesion, 3) the characteristic of pulmonary lesion (consolidation or atelectasis and tumor), and 4) presence of solid pleural tumor. The diagnostic accuracy of chest US was compared with CT scan in patients with pleural, pulmonary or other disease. In 32 patients with pleural effusion, differentiation between transudate and exudate was feasible in 27 (84%) patients with US and 26 (81%) patients with CT. In 32 patients with pulmonary and other pleural diseases, sensitivity, specificity and accuracy of US in lesion detection were 86%, 75% and 83% respectively when CT was regarded as a diagnostic gold standard. The diagnostic accuracy of chest US is comparable to CT in patients with hemithorax opacification on CXR

Chest CT findings in pediatric Wegener's granulomatosis

International Nuclear Information System (INIS)

Levine, Daniel; Akikusa, Jonathan; Manson, David; Silverman, Earl; Schneider, Rayfel

2007-01-01

Although pulmonary involvement occurs in the majority of children and adolescents with Wegener's granulomatosis (WG), relatively little has been published regarding the CT imaging manifestations in this group of patients. To determine the frequency and types of chest CT abnormalities in active pediatric WG (pWG). The study was a retrospective examination of 29 chest CT examinations performed at diagnosis (n=14) and during disease flares (n=15) in 18 children. The most common abnormalities were nodules (seen in 90% of examinations), ground-glass opacification (52%), and air-space opacification (45%). Of examinations with nodules, 73% demonstrated nodules >5 mm in diameter and 69% demonstrated more than five nodules; 17% had cavitary lesions. The only abnormality with a significant difference in prevalence between diagnosis and disease flares was air-space opacification, present in 71% and 20%, respectively (P < 0.01). In accordance with the findings of published adult studies and at variance with those of prior pediatric studies, our findings indicate that chest CT abnormalities in active pWG are frequent, most commonly comprising nodules and ground-glass opacification, which may be difficult to detect on plain radiography. We therefore advocate the routine use of chest CT for all affected patients, both at the time of presentation and during disease flares. (orig.)

Anteroposterior chest radiograph vs. chest CT scan in early detection of pneumothorax in trauma patients

Directory of Open Access Journals (Sweden)

Omar Hesham R

2011-09-01

Full Text Available Abstract Pneumothorax is a common complication following blunt chest wall trauma. In these patients, because of the restrictions regarding immobilization of the cervical spine, Anteroposterior (AP chest radiograph is usually the most feasible initial study which is not as sensitive as the erect chest X-ray or CT chest for detection of a pneumothorax. We will present 3 case reports which serve for better understanding of the entity of occult pneumothorax. The first case is an example of a true occult pneumothorax where an initial AP chest X-ray revealed no evidence of pneumothorax and a CT chest immediately performed revealed evidence of pneumothorax. The second case represents an example of a missed rather than a truly occult pneumothorax where the initial chest radiograph revealed clues suggesting the presence of pneumothorax which were missed by the reading radiologist. The third case emphasizes the fact that "occult pneumothorax is predictable". The presence of subcutaneous emphesema and pulmonary contusion should call for further imaging with CT chest to rule out pneumothorax. Thoracic CT scan is therefore the "gold standard" for early detection of a pneumothorax in trauma patients. This report aims to sensitize readers to the entity of occult pneumothorax and create awareness among intensivists and ER physicians regarding the proper diagnosis and management.

Anteroposterior chest radiograph vs. chest CT scan in early detection of pneumothorax in trauma patients.

Science.gov (United States)

Omar, Hesham R; Mangar, Devanand; Khetarpal, Suneel; Shapiro, David H; Kolla, Jaya; Rashad, Rania; Helal, Engy; Camporesi, Enrico M

2011-09-27

Pneumothorax is a common complication following blunt chest wall trauma. In these patients, because of the restrictions regarding immobilization of the cervical spine, Anteroposterior (AP) chest radiograph is usually the most feasible initial study which is not as sensitive as the erect chest X-ray or CT chest for detection of a pneumothorax. We will present 3 case reports which serve for better understanding of the entity of occult pneumothorax. The first case is an example of a true occult pneumothorax where an initial AP chest X-ray revealed no evidence of pneumothorax and a CT chest immediately performed revealed evidence of pneumothorax. The second case represents an example of a missed rather than a truly occult pneumothorax where the initial chest radiograph revealed clues suggesting the presence of pneumothorax which were missed by the reading radiologist. The third case emphasizes the fact that "occult pneumothorax is predictable". The presence of subcutaneous emphesema and pulmonary contusion should call for further imaging with CT chest to rule out pneumothorax. Thoracic CT scan is therefore the "gold standard" for early detection of a pneumothorax in trauma patients. This report aims to sensitize readers to the entity of occult pneumothorax and create awareness among intensivists and ER physicians regarding the proper diagnosis and management.

Clinical utility of coronary CT angiography with low-dose chest CT in the evaluation of patients with atypical chest pain: a preliminary report

International Nuclear Information System (INIS)

Lim, Soo Jin; Choo, Ki Seok; Kim, Chang Won

2008-01-01

To determine the clinical utility of coronary CT angiography (CCTA) with low-dose chest CT in the evaluation of patients with atypical chest pain. Ninety-six patients (mean age 60.2 years; age range, 41-68 years; 70 males) were referred for CCTA with low-dose chest CT (16-slice MDCT, Siemens) for an evaluation of atypical chest pain. When significant stenoses (lumen diameter reduction > 50%) were detected on CCTA, invasive coronary angiography (CA) was performed as the standard of reference. In all patients, medical chart review or telephone contact with patients was used to evaluate the contribution of CCTA with low-dose chest CT to the final clinical diagnosis, at least 6 months after performing CCTA. Among 96 patients, seven patients (7%) had significant stenoses as detected on CCTA, whereas two patients (2%) had significant stenoses and five patients had insignificant stenoses or no stenosis, as detected on conventional catheter angiography. In 18 (19%) of the 89 patients without significant stenosis detected on CCTA, this protocol provided additional information that suggested or confirmed an alternate clinical diagnosis. In patients with atypical chest pain, CCTA with low-dose chest CT could help to exclude ischemic heart disease and could provide important ancillary information for the final diagnosis

Application of low-dose radiation protocols in survey CT scans

International Nuclear Information System (INIS)

Fu Qiang; Liu Ting; Lu Tao; Xu Ke; Zhang Lin

2009-01-01

Objective: To characterize the protocols with low-dose radiation in survey CT scans for localization. Methods: Eighty standard adult patients, head and body phantoms were recruited. Default protocols provided by operator's manual setting were that all the tube voltage for head, chest, abdomen and lumbar was 120 kV; the tube currents were 20,10,20 and 40 mA, respectively. Values of kV and mA in the low-dose experiments were optimized according to the device options. For chest and abdomen, the tube position were compared between default (0 degree) and 180 degree. Phantoms were scanned with above protocols, and the radiation doses were measured respectively. Paired t-test were used for comparisons of standard deviation in CT value, noise and exposure surface dose (ESD) between group with default protocols and group with optimized protocols. Results: The optimized protocols in low-dose CT survey scans were 80 kV, 10 mA for head, 80 kV, 10 mA for chest, 80 kV, 10 mA for abdomen and 100 kV, 10 mA for lumbar. The values of ESD for phantom scan in default and optimized protocols were 0.38 mGy/0.16 mGy in head, 0.30 mGy/0.20 mGy in chest, 0.74 mGy/0.30 mGy in abdomen and 0.81 mGy/0.44 mGy in lumbar, respectively. Compared with default protocols, the optimized protocols reduced the radiation doses 59%, 33%, 59% and 46% in head, chest, abdomen and lumbar. When tube position changed from 0 degree to 180 degree, the ESD were 0.24 mGy/0.20 mGy for chest; 0.37 mGy/0.30 mGy for abdomen, and the radiation doses were reduced 20% and 17%. Conclusion: A certain amount of image noise is increased in low-dose protocols, but image quality is still acceptable without problem in CT localization. The reduction of radiation dose and the radiation harm to patients are the superiority. (authors)

Evaluation of a Chest Circumference-Adapted Protocol for Low-Dose 128-Slice Coronary CT Angiography with Prospective Electrocardiogram Triggering

Energy Technology Data Exchange (ETDEWEB)

Lu, Chenying; Wang, Zufei; Ji, Jiansong; Wang, Hailin; Hu, Xianghua; Chen, Chunmiao [Department of Radiology, Lishui Central Hospital, The Fifth Affiliated Hospital of Wenzhou Medical College, Lishui, Zhejiang 323000 (China)

2015-11-01

To assess the effect of chest circumference-adapted scanning protocol on radiation exposure and image quality in patients undergoing prospective electrocardiogram (ECG)-triggered coronary CT angiography (CCTA). One hundred-eighty-five consecutive patients, who had undergone prospective ECG triggering CCTA with a 128-slice CT, were included in the present study. Nipple-level chest circumference, body weight and height were measured before CT examinations. Patients were divided into four groups based on kV/ref·mAs = 100/200, 100/250, 120/200, and 120/250, when patient's chest circumference was ≤ 85.0 (n = 56), 85.0-90.0 (n = 53), 90.0-95.0 (n = 44), and > 95.0 (n = 32), respectively. Image quality per-segment was independently assessed by two experienced observers. Image noise and attenuation were also measured. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The effective radiation dose was calculated using CT dose volume index and the dose-length product. A significant correlation was observed between patients' chest circumference and body mass index (r = 0.762, p < 0.001). Chest circumference ranged from 74 to 105 cm, and the mean effective radiation dose was 1.9-3.8 mSv. Diagnostic image quality was obtained in 98.5% (2440/2478) of all evaluated coronary segments without any significant differences among the four groups (p = 0.650). No significant difference in image noise was observed among the four groups (p = 0.439), thus supporting the validity of the chest circumference-adapted scanning protocol. However, vessel attenuation, SNR and CNR were significantly higher in the 100 kV groups than in the 120 kV groups (p < 0.05). A measure of chest circumference can be used to adapt tube voltage and current for individualized radiation dose control, with resultant similar image noise and sustained diagnostic image quality.

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

Energy Technology Data Exchange (ETDEWEB)

Bodelle, Boris; Fischbach, Constanze; Booz, Christian; Yel, Ibrahim; Frellesen, Claudia; Kaup, Moritz; Beeres, Martin; Vogl, Thomas J.; Scholtz, Jan-Erik [Goethe University of Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany)

2017-06-15

Most of the applied radiation dose at CT is in the lower photon energy range, which is of limited diagnostic importance. 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. 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. 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). 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. (orig.)

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

International Nuclear Information System (INIS)

Bodelle, Boris; Fischbach, Constanze; Booz, Christian; Yel, Ibrahim; Frellesen, Claudia; Kaup, Moritz; Beeres, Martin; Vogl, Thomas J.; Scholtz, Jan-Erik

2017-01-01

Most of the applied radiation dose at CT is in the lower photon energy range, which is of limited diagnostic importance. 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. 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. 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). 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. (orig.)

Paediatrician awareness of radiation dose and inherent risks in chest imaging studies--a questionnaire study.

Science.gov (United States)

Heyer, Christoph M; Hansmann, Jan; Peters, Sören A; Lemburg, Stefan P

2010-11-01

To assess paediatricians' knowledge regarding radiation exposure of chest imaging. German paediatricians were surveyed using a questionnaire. Participants were asked to estimate effective dose (ED) of radiographs (CR) and computed tomography (CT). Further questions included dose-saving of paediatric CT-protocols, ALARA principle, and awareness of the link between radiation and cancer development. Length and type of occupation and amount of ordered procedures were evaluated. 137 paediatricians participated with 59% and 39% correctly estimating ED of an adult (0.01-0.1mSv) and newborn CR (0.01-0.1mSv), respectively. ED of an adult chest CT (1-10mSv) was underestimated by 28%, whereas ED of cardiac CT (10-100mSv) was underestimated by 54%. 35% of participants correctly estimated ED of a chest CT in an infant (10-100mSv) which was underestimated by 56%. Neither length nor type of occupation showed significant impact on dose estimations. 14% of paediatricians stated that MRI causes radiation, whereas 4% correctly estimated the potential of paediatric CT-protocols. 15% were familiar with the ALARA principle and 26% were aware of a publication concerning radiation and malignancy. Paediatricians demonstrated an increased level of awareness compared to previous surveys. However, estimation of ED of CT remained difficult. Increased information transfer and education seem pressing in the light of increasing radiological examinations. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

Comparison of patient specific dose metrics between chest radiography, tomosynthesis, and CT for adult patients of wide ranging body habitus

International Nuclear Information System (INIS)

Zhang, Yakun; Li, Xiang; Segars, W. Paul; Samei, Ehsan

2014-01-01

Purpose: Given the radiation concerns inherent to the x-ray modalities, accurately estimating the radiation doses that patients receive during different imaging modalities is crucial. This study estimated organ doses, effective doses, and risk indices for the three clinical chest x-ray imaging techniques (chest radiography, tomosynthesis, and CT) using 59 anatomically variable voxelized phantoms and Monte Carlo simulation methods. Methods: A total of 59 computational anthropomorphic male and female extended cardiac-torso (XCAT) adult phantoms were used in this study. Organ doses and effective doses were estimated for a clinical radiography system with the capability of conducting chest radiography and tomosynthesis (Definium 8000, VolumeRAD, GE Healthcare) and a clinical CT system (LightSpeed VCT, GE Healthcare). A Monte Carlo dose simulation program (PENELOPE, version 2006, Universitat de Barcelona, Spain) was used to mimic these two clinical systems. The Duke University (Durham, NC) technique charts were used to determine the clinical techniques for the radiographic modalities. An exponential relationship between CTDI vol and patient diameter was used to determine the absolute dose values for CT. The simulations of the two clinical systems compute organ and tissue doses, which were then used to calculate effective dose and risk index. The calculation of the two dose metrics used the tissue weighting factors from ICRP Publication 103 and BEIR VII report. Results: The average effective dose of the chest posteroanterior examination was found to be 0.04 mSv, which was 1.3% that of the chest CT examination. The average effective dose of the chest tomosynthesis examination was found to be about ten times that of the chest posteroanterior examination and about 12% that of the chest CT examination. With increasing patient average chest diameter, both the effective dose and risk index for CT increased considerably in an exponential fashion, while these two dose metrics

Comparison of patient specific dose metrics between chest radiography, tomosynthesis, and CT for adult patients of wide ranging body habitus

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yakun [Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Li, Xiang [Medical Physics Graduate Program, Department of Physics, Cleveland State University, Cleveland, Ohio 44115 (United States); Segars, W. Paul [Medical Physics Graduate Program, Carl E. Ravin Advanced Imaging Laboratories, and Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Samei, Ehsan, E-mail: samei@duke.edu [Medical Physics Graduate Program, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Departments of Physics, Biomedical Engineering, and Electrical and Computer Engineering, Duke University Medical Center, Durham, North Carolina 27705 (United States)

2014-02-15

Purpose: Given the radiation concerns inherent to the x-ray modalities, accurately estimating the radiation doses that patients receive during different imaging modalities is crucial. This study estimated organ doses, effective doses, and risk indices for the three clinical chest x-ray imaging techniques (chest radiography, tomosynthesis, and CT) using 59 anatomically variable voxelized phantoms and Monte Carlo simulation methods. Methods: A total of 59 computational anthropomorphic male and female extended cardiac-torso (XCAT) adult phantoms were used in this study. Organ doses and effective doses were estimated for a clinical radiography system with the capability of conducting chest radiography and tomosynthesis (Definium 8000, VolumeRAD, GE Healthcare) and a clinical CT system (LightSpeed VCT, GE Healthcare). A Monte Carlo dose simulation program (PENELOPE, version 2006, Universitat de Barcelona, Spain) was used to mimic these two clinical systems. The Duke University (Durham, NC) technique charts were used to determine the clinical techniques for the radiographic modalities. An exponential relationship between CTDI{sub vol} and patient diameter was used to determine the absolute dose values for CT. The simulations of the two clinical systems compute organ and tissue doses, which were then used to calculate effective dose and risk index. The calculation of the two dose metrics used the tissue weighting factors from ICRP Publication 103 and BEIR VII report. Results: The average effective dose of the chest posteroanterior examination was found to be 0.04 mSv, which was 1.3% that of the chest CT examination. The average effective dose of the chest tomosynthesis examination was found to be about ten times that of the chest posteroanterior examination and about 12% that of the chest CT examination. With increasing patient average chest diameter, both the effective dose and risk index for CT increased considerably in an exponential fashion, while these two dose

Evaluation of image quality and radiation dose by adaptive statistical iterative reconstruction technique level for chest CT examination.

Science.gov (United States)

Hong, Sun Suk; Lee, Jong-Woong; Seo, Jeong Beom; Jung, Jae-Eun; Choi, Jiwon; Kweon, Dae Cheol

2013-12-01

The purpose of this research is to determine the adaptive statistical iterative reconstruction (ASIR) level that enables optimal image quality and dose reduction in the chest computed tomography (CT) protocol with ASIR. A chest phantom with 0-50 % ASIR levels was scanned and then noise power spectrum (NPS), signal and noise and the degree of distortion of peak signal-to-noise ratio (PSNR) and the root-mean-square error (RMSE) were measured. In addition, the objectivity of the experiment was measured using the American College of Radiology (ACR) phantom. Moreover, on a qualitative basis, five lesions' resolution, latitude and distortion degree of chest phantom and their compiled statistics were evaluated. The NPS value decreased as the frequency increased. The lowest noise and deviation were at the 20 % ASIR level, mean 126.15 ± 22.21. As a result of the degree of distortion, signal-to-noise ratio and PSNR at 20 % ASIR level were at the highest value as 31.0 and 41.52. However, maximum absolute error and RMSE showed the lowest deviation value as 11.2 and 16. In the ACR phantom study, all ASIR levels were within acceptable allowance of guidelines. The 20 % ASIR level performed best in qualitative evaluation at five lesions of chest phantom as resolution score 4.3, latitude 3.47 and the degree of distortion 4.25. The 20 % ASIR level was proved to be the best in all experiments, noise, distortion evaluation using ImageJ and qualitative evaluation of five lesions of a chest phantom. Therefore, optimal images as well as reduce radiation dose would be acquired when 20 % ASIR level in thoracic CT is applied.

Pediatric chest CT after trauma: impact on surgical and clinical management

International Nuclear Information System (INIS)

Patel, Rina P.; Hernanz-Schulman, Marta; Hilmes, Melissa A.; Kan, J.H.; Yu, Chang; Ray, Jackie

2010-01-01

Chest CT after pediatric trauma is frequently performed but its clinical impact, particularly with respect to surgical intervention, has not been adequately evaluated. To assess the impact of chest CT compared with chest radiography on pediatric trauma management. Two hundred thirty-five consecutive pediatric trauma patients who had both chest CT and radiography were identified. Images were reviewed and findings were categorized and correlated with subsequent chest interventions, blinded to final outcome and management. Of the 235 children, 38.3% (90/235) had an abnormal chest radiograph and 63.8% (150/235) had an abnormal chest CT (P < 0.0001). Chest interventions followed in 4.7% (11/235); of these, the findings could be made 1 cm above the dome of the liver in 91% (10/11). Findings requiring chest intervention included pneumothorax (PTX) and vertebral fractures. PTX was found on 2.1% (5/235) of chest radiographs and 20.0% (47/235) of chest CTs (P < 0.0001); 1.7% (4/235) of the children received a chest tube for PTX, 0.85% (2/235) seen on chest CT only. Vertebral fractures were present in 3.8% of the children (9/235) and 66.7% (6/9) of those cases were treated with spinal fusion or brace. There were no instances of mediastinal vascular injury. Most intrathoracic findings requiring surgical management in our population were identified in the lower chest and would be included in routine abdominopelvic CT exams; this information needs to be taken into consideration in the diagnostic algorithm of pediatric trauma patients. (orig.)

Pediatric chest CT after trauma: impact on surgical and clinical management

Energy Technology Data Exchange (ETDEWEB)

Patel, Rina P. [Vanderbilt University School of Medicine, Nashville, TN (United States); Hernanz-Schulman, Marta; Hilmes, Melissa A.; Kan, J.H. [Vanderbilt University, Department of Radiology and Radiological Sciences, Vanderbilt Children' s Hospital, Nashville, TN (United States); Yu, Chang [Vanderbilt University, Department of Biostatistics, Nashville, TN (United States); Ray, Jackie [Vanderbilt University, Department of Pediatric Surgery, Vanderbilt Children' s Hospital, Nashville, TN (United States)

2010-07-15

Chest CT after pediatric trauma is frequently performed but its clinical impact, particularly with respect to surgical intervention, has not been adequately evaluated. To assess the impact of chest CT compared with chest radiography on pediatric trauma management. Two hundred thirty-five consecutive pediatric trauma patients who had both chest CT and radiography were identified. Images were reviewed and findings were categorized and correlated with subsequent chest interventions, blinded to final outcome and management. Of the 235 children, 38.3% (90/235) had an abnormal chest radiograph and 63.8% (150/235) had an abnormal chest CT (P < 0.0001). Chest interventions followed in 4.7% (11/235); of these, the findings could be made 1 cm above the dome of the liver in 91% (10/11). Findings requiring chest intervention included pneumothorax (PTX) and vertebral fractures. PTX was found on 2.1% (5/235) of chest radiographs and 20.0% (47/235) of chest CTs (P < 0.0001); 1.7% (4/235) of the children received a chest tube for PTX, 0.85% (2/235) seen on chest CT only. Vertebral fractures were present in 3.8% of the children (9/235) and 66.7% (6/9) of those cases were treated with spinal fusion or brace. There were no instances of mediastinal vascular injury. Most intrathoracic findings requiring surgical management in our population were identified in the lower chest and would be included in routine abdominopelvic CT exams; this information needs to be taken into consideration in the diagnostic algorithm of pediatric trauma patients. (orig.)

Estimating radiation risk induced by CT screening for Korean population

Science.gov (United States)

Yang, Won Seok; Yang, Hye Jeong; Min, Byung In

2017-02-01

The purposes of this study are to estimate the radiation risks induced by chest/abdomen computed tomography (CT) screening for healthcare and to determine the cancer risk level of the Korean population compared to other populations. We used an ImPACT CT Patient Dosimetry Calculator to compute the organ effective dose induced by CT screening (chest, low-dose chest, abdomen/pelvis, and chest/abdomen/pelvis CT). A risk model was applied using principles based on the BEIR VII Report in order to estimate the lifetime attributable risk (LAR) using the Korean Life Table 2010. In addition, several countries including Hong Kong, the United States (U.S.), and the United Kingdom, were selected for comparison. Herein, each population exposed radiation dose of 100 mSv was classified according to country, gender and age. For each CT screening the total organ effective dose calculated by ImPACT was 6.2, 1.5, 5.2 and 11.4 mSv, respectively. In the case of Korean female LAR, it was similar to Hong Kong female but lower than those of U.S. and U.K. females, except for those in their twenties. The LAR of Korean males was the highest for all types of CT screening. However, the difference of the risk level was negligible because of the quite low value.

Chest ultrasound in the evaluation of complicated pneumonia in the ICU patients: Can be viable alternative to CT?

Directory of Open Access Journals (Sweden)

Hesham El Sheikh

2014-06-01

Conclusion: Chest US provides an accurate evaluation of the pleural and parenchymal abnormalities associated with complicated pneumonia in the ICU patients. Considering that chest US is a bedside and avoids transportation of the patient outside ICU, free of radiation exposure and easily repeatable, chest US appears to be an attractive alternative to CT.

Spiral CT for evaluation of chest trauma; Spiral-CT beim Thoraxtrauma

Energy Technology Data Exchange (ETDEWEB)

Roehnert, W. [Universitaetsklinikum Dresden (Germany). Inst. und Poliklinik fuer Radiologische Diagnostik; Weise, R. [Universitaetsklinikum Dresden (Germany). Inst. und Poliklinik fuer Radiologische Diagnostik

1997-07-01

After implementation of spiral CT in our department, we carried out an analysis for determining anew the value of CT as a modality of chest trauma diagnosis in the emergency department. The retrospective study covers a period of 10 months and all emergency patients with chest trauma exmined by spiral CT. The major lesions of varying seriousness covered by this study are: pneumothorax, hematothorax, pulmonary contusion or laceration, mediastinal hematoma, rupture of a vessel, injury of the heart and pericardium. The various fractures are not included in this study. In many cases, spiral CT within relatively short time yields significant diagnostic findings, frequently saving additional angiography. A rigid diagnostic procedure cannot be formulated. Plain-film chest radiography still remains a diagnostic modality of high value. (Orig.) [Deutsch] Nach Einfuehrung der Spiral-CT in unserer Einrichtung versuchten wir, den Stellenwert der Computertomographie in der Notfalldiagnostik des Thoraxtraumas neu zu bestimmen. Dazu wurden retrospektiv ueber einen Zeitraum von 10 Monaten alle mittels Spiral-CT untersuchten Notfallpatienten mit Thoraxverletzungen ausgewertet. Im Vordergrund standen folgende Befunde unterschiedlichen Schweregrades: Pneumothorax, Haematothorax, Lungenkontusion/-lazeration, Mediastinalhaematom, Gefaessruptur, Herz- und Herzbeutelverletzung. Auf die unterschiedlichen Frakturen wird bewusst nicht naeher eingegangen. In vielen Faellen liefert die Spiral-CT mit relativ geringem Zeitaufwand wesentliche diagnostische Aussagen. Haeufig kann auf eine Angiographie verzichtet werden. Ein starres diagnostisches Stufenschema laesst sich nicht definieren. Die Thoraxuebersichtsaufnahme besitzt einen unveraendert hohen Stellenwert. (orig.)

Dual-source CT in chest pain diagnosis

International Nuclear Information System (INIS)

Johnson, Thorsten R.C.; Nikolaou, K.; Fink, C.; Rist, C.; Reiser, M.F.; Becker, C.R.; Becker, A.; Knez, A.

2007-01-01

With the depiction of pulmonary arteries, coronary arteries, and the aorta, CT angiography of the chest offers a comprehensive diagnostic work-up of unclear chest pain. The aim of this study was to assess the diagnostic accuracy of dual-source CT in this patient group. A total of 47 patients suffering from unclear chest pain were examined with a Siemens Somatom Definition. Volume and flow of contrast media (Ultravist, Schering) were adapted to the body weight. The examinations were evaluated with regard to image quality and contrast opacification and to the diagnostic accuracy with reference to the final clinical diagnosis. Adequate contrast opacification was achieved in all examinations. The depiction of the coronary arteries was diagnostic in all cases. The cause of chest pain could be identified in 41 cases. Among the diagnoses were coronary and myocardial pathologies, valvular disease, aortic aneurysms and dissections, pulmonary embolism, and pneumonic consolidation. DSCT angiography of the chest offers a very good image quality even at high heart rates so that a high diagnostic accuracy is achieved in patients with acute chest pain. (orig.) [de

Clinical Utility of Chest Computed Tomography in Patients with Rib Fractures CT Chest and Rib Fractures

OpenAIRE

Chapman, Brandon C.; Overbey, Douglas M.; Tesfalidet, Feven; Schramm, Kristofer; Stovall, Robert T.; French, Andrew; Johnson, Jeffrey L.; Burlew, Clay C.; Barnett, Carlton; Moore, Ernest E.; Pieracci, Fredric M.

2016-01-01

Background Chest CT is more sensitive than a chest X-ray (CXR) in diagnosing rib fractures; however, the clinical significance of these fractures remains unclear. Objectives The purpose of this study was to determine the added diagnostic use of chest CT performed after CXR in patients with either known or suspected rib fractures secondary to blunt trauma. Methods Retrospective coho...

Diagnosis of Grave's disease with pulmonary hypertension on chest CT.

Science.gov (United States)

Lee, Hwa Yeon; Yoo, Seung Min; Kim, Hye Rin; Chun, Eun Ju; White, Charles S

To evaluate the diagnostic accuracy of chest CT findings to diagnose Grave's disease in pulmonary hypertension. We retrospectively evaluated chest CT and the medical records of 13 patients with Grave's disease with (n=6) or without pulmonary hypertension (n=7) and in 17 control patients. Presence of iso-attenuation of diffusely enlarged thyroid glands compared with adjacent neck muscle on non-enhanced CT as a diagnostic clue of Grave's disease, and assessment of pulmonary hypertension on CT has high diagnostic accuracy. Chest CT has the potential to diagnose Grave's disease with pulmonary hypertension in the absence of other information. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of Localizer Radiography Projection on Organ Dose at Chest CT with Automatic Tube Current Modulation.

Science.gov (United States)

Saltybaeva, Natalia; Krauss, Andreas; Alkadhi, Hatem

2017-03-01

Purpose To calculate the effect of localizer radiography projections to the total radiation dose, including both the dose from localizer radiography and that from subsequent chest computed tomography (CT) with tube current modulation (TCM). Materials and Methods An anthropomorphic phantom was scanned with 192-section CT without and with differently sized breast attachments. Chest CT with TCM was performed after one localizer radiographic examination with anteroposterior (AP) or posteroanterior (PA) projections. Dose distributions were obtained by means of Monte Carlo simulations based on acquired CT data. For Monte Carlo simulations of localizer radiography, the tube position was fixed at 0° and 180°; for chest CT, a spiral trajectory with TCM was used. The effect of tube start angles on dose distribution was investigated with Monte Carlo simulations by using TCM curves with fixed start angles (0°, 90°, and 180°). Total doses for lungs, heart, and breast were calculated as the sum of the dose from localizer radiography and CT. Image noise was defined as the standard deviation of attenuation measured in 14 circular regions of interest. The Wilcoxon signed rank test, paired t test, and Friedman analysis of variance were conducted to evaluate differences in noise, TCM curves, and organ doses, respectively. Results Organ doses from localizer radiography were lower when using a PA instead of an AP projection (P = .005). The use of a PA projection resulted in higher TCM values for chest CT (P chest CT. © RSNA, 2016 Online supplemental material is available for this article.

Dose reduction with adaptive statistical iterative reconstruction for paediatric CT: phantom study and clinical experience on chest and abdomen CT.

Science.gov (United States)

Gay, F; Pavia, Y; Pierrat, N; Lasalle, S; Neuenschwander, S; Brisse, H J

2014-01-01

To assess the benefit and limits of iterative reconstruction of paediatric chest and abdominal computed tomography (CT). The study compared adaptive statistical iterative reconstruction (ASIR) with filtered back projection (FBP) on 64-channel MDCT. A phantom study was first performed using variable tube potential, tube current and ASIR settings. The assessed image quality indices were the signal-to-noise ratio (SNR), the noise power spectrum, low contrast detectability (LCD) and spatial resolution. A clinical retrospective study of 26 children (M:F = 14/12, mean age: 4 years, range: 1-9 years) was secondarily performed allowing comparison of 18 chest and 14 abdominal CT pairs, one with a routine CT dose and FBP reconstruction, and the other with 30 % lower dose and 40 % ASIR reconstruction. Two radiologists independently compared the images for overall image quality, noise, sharpness and artefacts, and measured image noise. The phantom study demonstrated a significant increase in SNR without impairment of the LCD or spatial resolution, except for tube current values below 30-50 mA. On clinical images, no significant difference was observed between FBP and reduced dose ASIR images. Iterative reconstruction allows at least 30 % dose reduction in paediatric chest and abdominal CT, without impairment of image quality. • Iterative reconstruction helps lower radiation exposure levels in children undergoing CT. • Adaptive statistical iterative reconstruction (ASIR) significantly increases SNR without impairing spatial resolution. • For abdomen and chest CT, ASIR allows at least a 30 % dose reduction.

CT findings of chest trauma

International Nuclear Information System (INIS)

Kim, Young Tong; Kim Young Il

1998-01-01

Trauma is the third leading cause of death, irrespective of age, and the leading cause of death in persons under 40 persons under 40 years of age. Most pleural, pulmonary, mediastinal, and diaphragmatic injuries are not seen on conventional chest radiographs, or are underestimated. In patients with chest trauma, CT scanning is an effective and sensitive method of detecting thoracic injuries and provides accurate information regarding their pattern and extent. (author). 5 refs., 17 figs

Possibilities of CT examinations by chest trauma

International Nuclear Information System (INIS)

Ftacnikova, B.

1994-01-01

Chest trauma represents the most frequent associated injury in multiply injured patients. The success of treatment depends also on prompt and effective diagnosis and extent of the injuries, on quality interdisciplinary approach. Author presents contributions of computed tomography (CT) in the management of 77 critically injured patients. Attention is focused on the efficacy of CT examination routinely employed in the setting of thoracic trauma and its relationship to following rationalization of treatment. CT scans of thorax is modality of choice for evaluating patients with occult pneumothorax, chest wall deformity of rib fractures, early diagnosis of lung contusion and laceration. (author). 13 figs., 1 tab., 7 refs

Chest Computed Tomography (CT) Immediately after CT-Guided Transthoracic Needle Aspiration Biopsy as a Predictor of Overt Pneumothorax

Science.gov (United States)

Noh, Tae June; Lee, Chang Hoon; Kang, Young Ae; Kwon, Sung-Youn; Yoon, Ho-Il; Kim, Tae Jung; Lee, Kyung Won; Lee, Jae Ho

2009-01-01

Background/Aims This study examined the correlation between pneumothorax detected by immediate post-transthoracic needle aspiration-biopsy (TTNB) chest computed tomography (CT) and overt pneumothorax detected by chest PA, and investigated factors that might influence the correlation. Methods Adult patients who had undergone CT-guided TTNB for lung lesions from May 2003 to June 2007 at Seoul National University Bundang Hospital were included. Immediate post-TTNB CT and chest PA follow-up at 4 and 16 hours after CT-guided TTNB were performed in 934 patients. Results Pneumothorax detected by immediate chest CT (CT-pneumothorax) was found in 237 (25%) and overt pneumothorax was detected by chest PA follow-up in 92 (38.8%) of the 237 patients. However, overt pneumothorax was found in 18 (2.6%) of the 697 patients without CT-pneumothorax. The width and depth of CT-pneumothorax were predictive risk factors for overt pneumothorax. Conclusions CT-pneumothorax is very sensitive for predicting overt pneumothorax, and the width and depth on CT-pneumothorax are reliable risk factors for predicting overt pneumothorax. PMID:19949733

Possibilities for exposure reduction in computed tomography examination of acute chest pain; Moeglichkeiten der Dosisreduktion bei CT-Untersuchungen des akuten Thoraxschmerzes

Energy Technology Data Exchange (ETDEWEB)

Becker, H.C. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Institut fuer Klinische Radiologie, Muenchen (Germany)

2012-10-15

Electrocardiogram-gated (ECG) computed tomography (CT) investigations can be accompanied by high amounts of radiation exposure. This is particularly true for the investigation of patients with unclear and acute chest pain. The common approach in patients with acute chest pain is standard spiral CT of the chest. The chest pain or triple-rule-out CT protocol is a relatively new ECG-gated protocol of the entire chest. This article reviews and discusses different techniques for the CT investigation of patients with acute chest pain. By applying the appropriate scan technique, the radiation exposure for an ECG-gated protocol must not necessarily be higher than a standard chest CT scan Aortic pathologies are far better depicted by ECG-gated scan protocols and depending on the heart rate coronary artery disease can also be detected at the same time. The use of ECG-triggered scans will not support the diagnostics of the pulmonary arteries. However, in unspecific chest pain an ECG-triggered scan protocol can provide information on the differential diagnosis. (orig.) [German] EKG-getriggerte CT-Untersuchungen koennen mit einer relativ hohen Strahlenexposition einhergehen. Dies gilt im besonderen Masse fuer die Untersuchung des gesamten Thorax bei Patienten mit unklarem akutem Thoraxschmerz. Bisher wurden Untersuchungen bei Patienten mit akutem Thoraxschmerz in Spiraltechnik ohne EKG-Triggerung durchgefuehrt. Das ''Chest-pain-'' oder ''Triple-rule-out''-Protokoll ist ein neues EKG-getriggertes Untersuchungsprotokoll des gesamten Thorax. Im vorliegenden Artikel werden verschiedene Techniken zur CT-Untersuchung von Patienten mit akutem Thoraxschmerz vorgestellt und besprochen. Mit der richtigen Untersuchungstechnik muss die Strahlenexposition fuer ein EKG-getriggertes Untersuchungsprotokoll nicht hoeher sein als eine Standarduntersuchung ohne EKG. Mit einem EKG-getriggerten Untersuchungsprotokoll laesst sich die Aorta in Hinblick auf

Cardiac pathologies incidentally detected with non-gated chest CT; Inzidentelle Pathologien des Herzens im Thorax-CT

Energy Technology Data Exchange (ETDEWEB)

Scherer, Axel; Kroepil, P.; Lanzman, R.S.; Moedder, U. [Inst. fuer Radiologie, Universitaetsklinikum Duesseldorf, Heinrich-Heine-Univ. (Germany); Choy, G.; Abbara, S. [Cardiovascular Imaging Section, Massachusetts General Hospital, Harvard Medical School (United States)

2009-12-15

Cardiac imaging using electrocardiogram-gated multi-detector computed tomography (MDCT) permits noninvasive diagnosis of congenital and acquired cardiac pathologies and has thus become increasingly important in the last years. Several studies investigated the incidence and relevance of incidental extracardiac structures within the lungs, mediastinum, chest wall, and abdomen with gated coronary CT. This resulted in the general acceptance of the review of extracardiac structures as a routine component of coronary CT interpretation. On the other hand radiologists tend to neglect pericardial and cardiac pathologies in non-gated chest CT, which is primarily performed for the evaluation of the respiratory system or for tumor staging. Since the introduction of multi-detector spiral CT technology, the incidental detection of cardiac and pericardial findings has become possible using non-gated chest CT. This article reviews the imaging appearances and differential diagnostic considerations of incidental cardiac entities that may be encountered in non-gated chest CT. (orig.)

Conceptus radiation dose and risk from chest screen-film radiography

International Nuclear Information System (INIS)

Damilakis, John; Perisinakis, Kostas; Dimovasili, Evangelia; Prassopoulos, Panos; Gourtsoyiannis, Nicholas; Varveris, Haralambos

2003-01-01

The objectives of the present study were to (a) estimate the conceptus radiation dose and risks for pregnant women undergoing posteroanterior and anteroposterior (AP) chest radiographs, (b) study the conceptus dose as a function of chest thickness of the patient undergoing chest radiograph, and (c) investigate the possibility of a conceptus to receive a dose of more than 10 mGy, the level above which specific measurements of conceptus doses may be necessary. Thermoluminescent dosimeters were used for dose measurements in anthropomorphic phantoms simulating pregnancy at the three trimesters of gestation. The effect of chest thickness on conceptus dose and risk was studied by adding slabs of lucite on the anterior and posterior surface of the phantom chest. The conceptus risk for radiation-induced childhood fatal cancer and hereditary effects was calculated based on appropriate risk factors. The average AP chest dimension (d a ) was estimated for 51 women of childbearing age from chest CT examinations. The value of d a was estimated to be 22.3 cm (17.4-27.2 cm). The calculated maximum conceptus dose was 107 x 10 -3 mGy for AP chest radiographs performed during the third trimester of pregnancy with maternal chest thickness of 27.2 cm. This calculation was based on dose data obtained from measurements in the phantoms and d a estimated from the patient group. The corresponding average excess of childhood cancer was 10.7 per million patients. The risk for hereditary effects was 1.1 per million births. Radiation dose for a conceptus increases exponentially as chest thickness increases. The conceptus dose at the third trimester is higher than that of the second and first trimesters. The results of the current study suggest that chest radiographs carried out in women at any time during gestation will result in a negligible increase in risk of radiation-induced harmful effects to the unborn child. After a properly performed maternal chest X-ray, there is no need for

Conceptus radiation dose and risk from chest screen-film radiography.

Science.gov (United States)

Damilakis, John; Perisinakis, Kostas; Prassopoulos, Panos; Dimovasili, Evangelia; Varveris, Haralambos; Gourtsoyiannis, Nicholas

2003-02-01

The objectives of the present study were to (a) estimate the conceptus radiation dose and risks for pregnant women undergoing posteroanterior and anteroposterior (AP) chest radiographs, (b) study the conceptus dose as a function of chest thickness of the patient undergoing chest radiograph, and (c) investigate the possibility of a conceptus to receive a dose of more than 10 mGy, the level above which specific measurements of conceptus doses may be necessary. Thermoluminescent dosimeters were used for dose measurements in anthropomorphic phantoms simulating pregnancy at the three trimesters of gestation. The effect of chest thickness on conceptus dose and risk was studied by adding slabs of lucite on the anterior and posterior surface of the phantom chest. The conceptus risk for radiation-induced childhood fatal cancer and hereditary effects was calculated based on appropriate risk factors. The average AP chest dimension (d(a)) was estimated for 51 women of childbearing age from chest CT examinations. The value of d(a) was estimated to be 22.3 cm (17.4-27.2 cm). The calculated maximum conceptus dose was 107 x 10(-3) mGy for AP chest radiographs performed during the third trimester of pregnancy with maternal chest thickness of 27.2 cm. This calculation was based on dose data obtained from measurements in the phantoms and d(a) estimated from the patient group. The corresponding average excess of childhood cancer was 10.7 per million patients. The risk for hereditary effects was 1.1 per million births. Radiation dose for a conceptus increases exponentially as chest thickness increases. The conceptus dose at the third trimester is higher than that of the second and first trimesters. The results of the current study suggest that chest radiographs carried out in women at any time during gestation will result in a negligible increase in risk of radiation-induced harmful effects to the unborn child. After a properly performed maternal chest X-ray, there is no need for

Conceptus radiation dose and risk from chest screen-film radiography

Energy Technology Data Exchange (ETDEWEB)

Damilakis, John; Perisinakis, Kostas; Dimovasili, Evangelia [Department of Medical Physics, University of Crete, Faculty of Medicine, P.O. Box 1393, 714 09 Iraklion, Crete (Greece); Prassopoulos, Panos; Gourtsoyiannis, Nicholas [Department of Radiology, University of Crete, Faculty of Medicine, P.O. Box 1393, 714 09 Iraklion, Crete (Greece); Varveris, Haralambos [Department of Radiotherapy, University of Crete, Faculty of Medicine, P.O. Box 1393, 714 09 Iraklion, Crete (Greece)

2003-02-01

The objectives of the present study were to (a) estimate the conceptus radiation dose and risks for pregnant women undergoing posteroanterior and anteroposterior (AP) chest radiographs, (b) study the conceptus dose as a function of chest thickness of the patient undergoing chest radiograph, and (c) investigate the possibility of a conceptus to receive a dose of more than 10 mGy, the level above which specific measurements of conceptus doses may be necessary. Thermoluminescent dosimeters were used for dose measurements in anthropomorphic phantoms simulating pregnancy at the three trimesters of gestation. The effect of chest thickness on conceptus dose and risk was studied by adding slabs of lucite on the anterior and posterior surface of the phantom chest. The conceptus risk for radiation-induced childhood fatal cancer and hereditary effects was calculated based on appropriate risk factors. The average AP chest dimension (d{sub a}) was estimated for 51 women of childbearing age from chest CT examinations. The value of d{sub a} was estimated to be 22.3 cm (17.4-27.2 cm). The calculated maximum conceptus dose was 107 x 10{sup -3} mGy for AP chest radiographs performed during the third trimester of pregnancy with maternal chest thickness of 27.2 cm. This calculation was based on dose data obtained from measurements in the phantoms and d{sub a} estimated from the patient group. The corresponding average excess of childhood cancer was 10.7 per million patients. The risk for hereditary effects was 1.1 per million births. Radiation dose for a conceptus increases exponentially as chest thickness increases. The conceptus dose at the third trimester is higher than that of the second and first trimesters. The results of the current study suggest that chest radiographs carried out in women at any time during gestation will result in a negligible increase in risk of radiation-induced harmful effects to the unborn child. After a properly performed maternal chest X-ray, there is

Automated tube potential selection for standard chest and abdominal CT in follow-up patients with testicular cancer: comparison with fixed tube potential

Energy Technology Data Exchange (ETDEWEB)

Gnannt, Ralph; Winklehner, Anna; Frauenfelder, Thomas; Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Eberli, Daniel [University Hospital Zurich, Clinic for Urology, Zurich (Switzerland); Knuth, Alexander [University Hospital Zurich, Clinic for Oncology, Zurich (Switzerland)

2012-09-15

To evaluate prospectively, in patients with testicular cancer, the radiation dose-saving potential and image quality of contrast-enhanced chest and abdominal CT with automated tube potential selection. Forty consecutive patients with testicular cancer underwent contrast-enhanced arterio-venous chest and portal-venous abdominal CT with automated tube potential selection (protocol B; tube potential 80-140 kVp), which is based on the attenuation of the CT topogram. All had a first CT at 120 kVp (protocol A) using the same 64-section CT machine and similar settings. Image quality was assessed; dose information (CTDI{sub vol}) was noted. Image noise and attenuation in the liver and spleen were significantly higher for protocol B (P < 0.05 each), whereas attenuation in the deltoid and erector spinae muscles was similar. In protocol B, tube potential was reduced to 100 kVp in 18 chest and 33 abdominal examinations, and to 80 kVp in 5 abdominal CT examinations; it increased to 140 kVp in one patient. Image quality of examinations using both CT protocols was rated as diagnostic. CTDI{sub vol} was significantly lower for protocol B compared to protocol A (reduction by 12%, P < 0.01). In patients with testicular cancer, radiation dose of chest and abdominal CT can be reduced with automated tube potential selection, while image quality is preserved. (orig.)

Evaluation of the Significance of Incidental Breast Lesions Detected by Chest CT

International Nuclear Information System (INIS)

Kim, Jae Hyun; Chang, Yun Woo; Hwang, Jung Hwa; Kim, Hyung Hwan; Lee, Eun Hye; Yang, Seung Boo

2013-01-01

To evaluate the significance of incidentally detected breast lesions on a chest CT scan. Thirty-six incidental breast lesions in 26 patients were detected on a chest CT scan and were correlated with breast sonography, retrospectively. Among them, twenty-four breast lesions in 20 patients that were correlated with chest CT and sonography were available to pathology or follow up sonography. The CT findings were compared with sonographic findings according to the pathologic results. Incidentally detected breast lesions on a chest CT scan were correlated with sonography in 86% (31/36). Among 24 lesions that were available to pathology or follow up sonography, seven (29.2%) lesions were malignant and 17 (70.8%) lesions were benign. CT revealed a significant difference between benign and malignant lesions in terms of shape and margin (p = 0.007; p = 0.008, respectively). The CT findings were well correlated with sonographic findings in shape and margin (p = 0.001, respectively). Incidentally detected breast lesions on chest CT can be correlated with sonography. An irregular shape or a non-circumscribed margin of breast lesions on a CT scan can be considered as a suggestive sign of malignancy.

Chest CT findings of toxocariasis: Correlation with laboratory results

International Nuclear Information System (INIS)

Hur, J.H.; Lee, I.J.; Kim, J.-H.; Kim, D.-G.; Hwang, H.J.; Koh, S.H.; Lee, K.

2014-01-01

Aim: To assess the relationship between chest computed tomography (CT) findings of patients with toxocariasis and levels of serological markers. Materials and methods: A total of 38 cases of patients diagnosed with toxocariasis by enzyme-linked immunosorbent assay (ELISA), CT, and serological markers were retrospectively reviewed. The presence of nodule with or without ground-glass opacity (GGO) halo, consolidation, focal GGO, pleural effusion, and lymphadenopathy at chest CT were evaluated. Statistical analysis was performed with the Fisher's exact test. Results: The most common chest CT findings were nodule (n = 12, 31.6%) and focal GGO (n = 12, 31.6%). In patients with normal eosinophil levels, focal GGO (n = 9, 37.5%) was the most common finding. In contrast, nodule with a GGO halo (n = 7, 50%) was the most common finding in the eosinophilia group. Nodule with a GGO halo was more common in the eosinophilia group, with a statistically significant difference (p = 0.017). Nodule was more common in the eosinophilia group, and focal GGO was more common in the normal eosinophil group. Conclusion: The most common chest CT findings in toxocariasis were nodule with or without GGO halo, and focal GGO. In the eosinophilia group, nodule with a GGO halo was significantly more frequent. Other CT findings did not show a statistically significant relationship with serological markers

Chest CT findings in pediatric Wegener's granulomatosis

Energy Technology Data Exchange (ETDEWEB)

Levine, Daniel [British Columbia Children' s Hospital, Department of Radiology and Nuclear Medicine, Vancouver, British Columbia (Canada); Akikusa, Jonathan [Royal Children' s Hospital Melbourne, Department of Rheumatology, Melbourne (Australia); Manson, David [Hospital for Sick Children, Department of Radiology, Toronto (Canada); Silverman, Earl; Schneider, Rayfel [Hospital for Sick Children, Department of Rheumatology, Toronto (Canada)

2007-01-15

Although pulmonary involvement occurs in the majority of children and adolescents with Wegener's granulomatosis (WG), relatively little has been published regarding the CT imaging manifestations in this group of patients. To determine the frequency and types of chest CT abnormalities in active pediatric WG (pWG). The study was a retrospective examination of 29 chest CT examinations performed at diagnosis (n=14) and during disease flares (n=15) in 18 children. The most common abnormalities were nodules (seen in 90% of examinations), ground-glass opacification (52%), and air-space opacification (45%). Of examinations with nodules, 73% demonstrated nodules >5 mm in diameter and 69% demonstrated more than five nodules; 17% had cavitary lesions. The only abnormality with a significant difference in prevalence between diagnosis and disease flares was air-space opacification, present in 71% and 20%, respectively (P < 0.01). In accordance with the findings of published adult studies and at variance with those of prior pediatric studies, our findings indicate that chest CT abnormalities in active pWG are frequent, most commonly comprising nodules and ground-glass opacification, which may be difficult to detect on plain radiography. We therefore advocate the routine use of chest CT for all affected patients, both at the time of presentation and during disease flares. (orig.)

Pulmonary effects of synthetic marijuana: chest radiography and CT findings.

Science.gov (United States)

Berkowitz, Eugene A; Henry, Travis S; Veeraraghavan, Srihari; Staton, Gerald W; Gal, Anthony A

2015-04-01

The purpose of this article is to present the first chest radiographic and CT descriptions of organizing pneumonia in response to smoking synthetic marijuana. Chest radiographs showed a diffuse miliary-micronodular pattern. Chest CT images showed diffuse centrilobular nodules and tree-in-bud pattern and a histopathologic pattern of organizing pneumonia with or without patchy acute alveolar damage. This distinct imaging pattern should alert radiologists to include synthetic marijuana abuse in the differential diagnosis.

CT analysis of pulmonary injuries from blunt chest trauma

International Nuclear Information System (INIS)

Konno, Shoko

1996-01-01

The purpose of this paper is to analyze the CT findings of pulmonary parenchymal injuries due to blunt chest trauma and to categorize CT findings on the basis of their outcome. The materials of this study consist of 62 patients who had pulmonary injuries on CT obtained within 6 hours after blunt chest trauma. CT findings were analysed with regards to the shape, size, and distribution of the lesions. Follow-up CT scans were obtained in 35 patients at intervals from 1 day to 1 month after the initial CT study. CT showed ill-defined opacities in 59 patients (64 lesions in the peripheral area and 95 in the non-peripheral area) and pulmonary nodules with or without cavitary lesions in 30 patients (7 lesions in the peripheral area and 31 in the non-peripheral area). Follow-up CT allowed the classification of these pulmonary injuries into 3 types; the non-peripheral, ill-defined opacities showing immediate clearing, nodules with or without cavitary lesions over 1 cm in diameter showing prolongation, and the peripheral ill-defined opacities adjacent to the thoracic cage, and small nodules with or without cavitary lesions within 1 cm in diameter, showing various courses. CT has marked advantage over plain chest radiographs not only in the detection rate but in accurate estimation of the prognosis of the lesions. (author)

Securing safe and informative thoracic CT examinations—Progress of radiation dose reduction techniques

Energy Technology Data Exchange (ETDEWEB)

Kubo, Takeshi, E-mail: tkubo@kuhp.kyoto-u.ac.jp [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507 (Japan); Ohno, Yoshiharu [Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan); Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan); Seo, Joon Beom [Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505 (Korea, Republic of); Yamashiro, Tsuneo [Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, 207 Uehara, Nishinara, Okinawa 903-0215 (Japan); Kalender, Willi A. [Institute of Medical Physics, Friedrich-Alexander-University Erlangen-Nürnberg, Henkestr. 91, 91052 Erlangen (Germany); Lee, Chang Hyun [Department of Radiology, Seoul National University Hospital, 28 Yeongeon-dong, Jongno-gu, Seoul (Korea, Republic of); Lynch, David A. [Department of Radiology, National Jewish Health, 1400 Jackson St, A330 Denver, Colorado 80206 (United States); Kauczor, Hans-Ulrich [Diagnostic and Interventional Radiology, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg (Germany); Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), Im Neuenheimer Feld 400, 69120 Heidelberg (Germany); Hatabu, Hiroto, E-mail: hhatabu@partners.org [Center for Pulmonary Functional Imaging, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States)

2017-01-15

Highlights: • Various techniques have led to substantial radiation dose reduction of chest CT. • Automatic modulation of tube current has been shown to reduce radiation dose. • Iterative reconstruction makes significant radiation dose reduction possible. • Processing time is a limitation for full iterative reconstruction, currently. • Validation of diagnostic accuracy is desirable for routine use of low dose protocols. - Abstract: The increase in the radiation exposure from CT examinations prompted the investigation on the various dose-reduction techniques. Significant dose reduction has been achieved and the level of radiation exposure of thoracic CT is expected to reach the level equivalent to several chest X-ray examinations. With more scanners with advanced dose reduction capability deployed, knowledge on the radiation dose reduction methods has become essential to clinical practice as well as academic research. This article reviews the history of dose reduction techniques, ongoing changes brought by newer technologies and areas of further investigation.

Intra-abdominal fat area measurement using chest CT data

International Nuclear Information System (INIS)

Moriya, Hiroshi; Midorikawa, Shigeo; Hashimoto, Kouji; Ishii, Akira; Saitou, Kumi; Andou, Tomonori; Kitamura, Naoko; Sakuma, Koutarou

2007-01-01

Intra-abdominal fat obesity, which is linked with the metabolic syndrome, is usually characterized by measuring intra-abdominal fat area at the umbilical level of abdominal CT scan. In recent year, the chances of chest CT scanning are increased, as lung cancer screening survey or individual medical examination. Thus, we presented a method of measuring the areas of intra-abdominal fat and subcutaneous fat at the lower slice of chest CT scan. Fat areas found with this method were significantly correlated with those obtained at the umbilical level. (author)

Chest pain: Coronary CT in the ER

NARCIS (Netherlands)

E. Maffei (Erica); S. Seitun (Sara); A.I. Guaricci (Andrea); F. Cademartiri (Filippo)

2016-01-01

textabstractCardiac CT has developed into a robust clinical tool during the past 15 years. Of the fields in which the potential of cardiac CT has raised more interest is chest pain in acute settings. In fact, the possibility to exclude with high reliability obstructive coronary artery disease (CAD)

1024 matrix image reconstruction: usefulness in high resolution chest CT

International Nuclear Information System (INIS)

Jeong, Sun Young; Chung, Myung Jin; Chong, Se Min; Sung, Yon Mi; Lee, Kyung Soo

2006-01-01

We tried to evaluate whether high resolution chest CT with a 1,024 matrix has a significant advantage in image quality compared to a 512 matrix. Each set of 512 and 1024 matrix high resolution chest CT scans with both 0.625 mm and 1.25 mm slice thickness were obtained from 26 patients. Seventy locations that contained twenty-four low density lesions without sharp boundary such as emphysema, and forty-six sharp linear densities such as linear fibrosis were selected; these were randomly displayed on a five mega pixel LCD monitor. All the images were masked for information concerning the matrix size and slice thickness. Two chest radiologists scored the image quality of each ar rowed lesion as follows: (1) undistinguishable, (2) poorly distinguishable, (3) fairly distinguishable, (4) well visible and (5) excellently visible. The scores were compared from the aspects of matrix size, slice thickness and the different observers by using ANOVA tests. The average and standard deviation of image quality were 3.09 (± .92) for the 0.625 mm x 512 matrix, 3.16 (± .84) for the 0.625 mm x 1024 matrix, 2.49 (± 1.02) for the 1.25 mm x 512 matrix, and 2.35 (± 1.02) for the 1.25 mm x 1024 matrix, respectively. The image quality on both matrices of the high resolution chest CT scans with a 0.625 mm slice thickness was significantly better than that on the 1.25 mm slice thickness (ρ < 0.001). However, the image quality on the 1024 matrix high resolution chest CT scans was not significantly different from that on the 512 matrix high resolution chest CT scans (ρ = 0.678). The interobserver variation between the two observers was not significant (ρ = 0.691). We think that 1024 matrix image reconstruction for high resolution chest CT may not be clinical useful

Ultralow dose CT for pulmonary nodule detection with chest X-ray equivalent dose - a prospective intra-individual comparative study

Energy Technology Data Exchange (ETDEWEB)

Messerli, Michael [University Zurich, Department of Nuclear Medicine, University Hospital Zurich, Zurich (Switzerland); Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Kluckert, Thomas; Knitel, Meinhard; Desbiolles, Lotus; Bauer, Ralf W.; Wildermuth, Simon [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Waelti, Stephan [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); University of Montreal, Department of Radiology, CHU Sainte-Justine, Montreal, Quebec (Canada); Rengier, Fabian [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Warschkow, Rene [Cantonal Hospital St. Gallen, Department of Surgery, St. Gallen (Switzerland); Alkadhi, Hatem [University Zurich, Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich (Switzerland); Leschka, Sebastian [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); University Zurich, Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich (Switzerland)

2017-08-15

To prospectively evaluate the accuracy of ultralow radiation dose CT of the chest with tin filtration at 100 kV for pulmonary nodule detection. 202 consecutive patients undergoing clinically indicated chest CT (standard dose, 1.8 ± 0.7 mSv) were prospectively included and additionally scanned with an ultralow dose protocol (0.13 ± 0.01 mSv). Standard dose CT was read in consensus by two board-certified radiologists to determine the presence of lung nodules and served as standard of reference (SOR). Two radiologists assessed the presence of lung nodules and their locations on ultralow dose CT. Sensitivity and specificity of the ultralow dose protocol was compared against the SOR, including subgroup analyses of different nodule sizes and types. A mixed effects logistic regression was used to test for independent predictors for sensitivity of pulmonary nodule detection. 425 nodules (mean diameter 3.7 ± 2.9 mm) were found on SOR. Overall sensitivity for nodule detection by ultralow dose CT was 91%. In multivariate analysis, nodule type, size and patients BMI were independent predictors for sensitivity (p < 0.001). Ultralow dose chest CT at 100 kV with spectral shaping enables a high sensitivity for the detection of pulmonary nodules at exposure levels comparable to plain film chest X-ray. (orig.)

Detection of breast abnormalities on enhanced chest CT: Correlation with breast composition on mammography

Energy Technology Data Exchange (ETDEWEB)

Cho, Eun Mi; Kang, Hee; Shin, Young Gyung; Yun, Jong Hyouk; Oh, Kyung Seung [Dept. of Radiology, Kosin University Gospel Hospital, Kosin University College of Medicine, Busan (Korea, Republic of)

2017-02-15

To investigate the capability of enhanced chest computed tomography (CT) for detecting breast abnormalities and to assess the influence of breast composition on this detectability. From 2000 to 2013, 75 patients who underwent mammography, breast sonography, and enhanced chest CT within one month and had abnormalities on sonography were included. Detection rate of breast abnormality on enhanced chest CT was compared among 4 types of breast composition by the Breast Imaging Reporting and Data System. Contribution of breast composition, size and enhancement of target lesions to detectability of enhanced chest CT was assessed using logistic regression and chi-square test. Of the 75 target lesions, 34 (45.3%) were detected on enhanced chest CT, corresponding with those on breast sonography; there were no significantly different detection rates among the 4 types of breast composition (p = 0.078). Breast composition [odds ratio (OR) = 1.07, p = 0.206] and enhancement (OR = 21.49, p = 0.998) had no significant effect, but size (OR = 1.23, p = 0.004) was a significant contributing factor influencing the detectability of enhanced chest CT for breast lesions. About half of the cases (45.3%) demonstrated breast lesions on chest CT corresponding with target lesions on sonography. Breast composition defined on mammography did not affect the detectability of enhanced chest CT for breast lesions.

Chest wall tuberculosis; CT findings in 14 patients

Energy Technology Data Exchange (ETDEWEB)

Han, Young Min; Lee, Sang Yong; Lee, Dong Won; Kim, Chong Soo; Chung, Gyung Ho; Sohn, Myung Hee; Choi, Ki Chul [Chonbuk National Univ. School of Medicine, Chonju (Korea, Republic of); Kim, Dong Woo [Daejoen Eulji Hospital, Daejon (Korea, Republic of); Juhng, Seon Kwan [Wonkwang Univ. Medical School, Iksan (Korea, Republic of)

1996-01-01

To present CT findings of chest wall tuberculosis. CT scans were obtained in 14 patients with proven chest wall tuberculosis. Diagnosis was confirmed by means of right open thoracostomy with abscess evacuation (n=1), excision and curettage (n=11) or excision and curettage along with resection of the involved lung (n=2). The images were assessed with emphasis for the extrapleural, pleural, and pulmonary lesions. All patients showed juxtacostal soft tissue mass with central low attenuation and peripheral rim enhancement. The lesions were located in the left hemithorax in eight patients and in the right in six. Multiple lesions were found in three patients (two in one and three in two). Rib destruction was observed in four patients. Intercostal muscle involvement of thickening and enhancement were shown in all patients. Thirteen patients (93%) had evidence of pulmonary tuberculosis: active pulmonary tuberculosis in nine and stable tuberculosis in four. Pleural lesions, including empyema necessitatis in six, were observed in eleven (79%). On CT scan, chest wall tuberculosis is characterized by juxtacostal soft tissue lesion with central low attenuation and peripheral rim enhancement. Rib destruction may be associated. Additionally, enhancing intercostal muscle suggest direct inflammatory process of tuberculosis and spread channel to the chest wall involvement of pleuropulmonary tuberculosis.

Chest wall tuberculosis; CT findings in 14 patients

International Nuclear Information System (INIS)

Han, Young Min; Lee, Sang Yong; Lee, Dong Won; Kim, Chong Soo; Chung, Gyung Ho; Sohn, Myung Hee; Choi, Ki Chul; Kim, Dong Woo; Juhng, Seon Kwan

1996-01-01

To present CT findings of chest wall tuberculosis. CT scans were obtained in 14 patients with proven chest wall tuberculosis. Diagnosis was confirmed by means of right open thoracostomy with abscess evacuation (n=1), excision and curettage (n=11) or excision and curettage along with resection of the involved lung (n=2). The images were assessed with emphasis for the extrapleural, pleural, and pulmonary lesions. All patients showed juxtacostal soft tissue mass with central low attenuation and peripheral rim enhancement. The lesions were located in the left hemithorax in eight patients and in the right in six. Multiple lesions were found in three patients (two in one and three in two). Rib destruction was observed in four patients. Intercostal muscle involvement of thickening and enhancement were shown in all patients. Thirteen patients (93%) had evidence of pulmonary tuberculosis: active pulmonary tuberculosis in nine and stable tuberculosis in four. Pleural lesions, including empyema necessitatis in six, were observed in eleven (79%). On CT scan, chest wall tuberculosis is characterized by juxtacostal soft tissue lesion with central low attenuation and peripheral rim enhancement. Rib destruction may be associated. Additionally, enhancing intercostal muscle suggest direct inflammatory process of tuberculosis and spread channel to the chest wall involvement of pleuropulmonary tuberculosis

Atelectasis on pediatric chest CT: comparison of sedation techniques

International Nuclear Information System (INIS)

Sargent, M.A.; McEachern, A.M.; Jamieson, D.H.

1999-01-01

Background. A change in practice at our institution resulted in increased use of anesthesia for CT scan of the chest in children who required sedation. Objective. To determine whether there is a difference in the frequency or severity of pulmonary atelectasis on CT scan in children sedated by anesthesiologists compared with children sedated by radiologists using intravenous pentobarbital. Materials and methods. Retrospective blinded review of 60 CT scans of the chest performed in 41 children. Forty-one studies in children sedated by radiologists (median age 29 months) were compared with 19 studies in children sedated by anesthesiologists (median age 25 months). Results. Atelectasis sufficient to obscure pulmonary metastases was shown in 5 of 41 (12 %) radiology sedations and 13 of 19 (68 %) anesthesiology sedations (P < 0.01). Higher grades of atelectasis were recorded in children under anesthesia (P < 0.01). Conclusion. Atelectasis is more frequent and more severe in children undergoing general anesthesia compared with intravenous pentobarbital sedation. Consideration should be given to the use of forced inspiration in children anesthetized for CT scan of the chest. (orig.)

Prevalence and Diagnostic Performance of Isolated and Combined NEXUS Chest CT Decision Criteria.

Science.gov (United States)

Raja, Ali S; Mower, William R; Nishijima, Daniel K; Hendey, Gregory W; Baumann, Brigitte M; Medak, Anthony J; Rodriguez, Robert M

2016-08-01

The use of chest computed tomography (CT) to evaluate emergency department patients with adult blunt trauma is rising. The NEXUS Chest CT decision instruments are highly sensitive identifiers of adult blunt trauma patients with thoracic injuries. However, many patients without injury exhibit one of more of the criteria so cannot be classified "low risk." We sought to determine screening performance of both individual and combined NEXUS Chest CT criteria as predictors of thoracic injury to inform chest CT imaging decisions in "non-low-risk" patients. This was a secondary analysis of data on patients in the derivation and validation cohorts of the prospective, observational NEXUS Chest CT study, performed September 2011 to May 2014 in 11 Level I trauma centers. Institutional review board approval was obtained at all study sites. Adult blunt trauma patients receiving chest CT were included. The primary outcome was injury and major clinical injury prevalence and screening performance in patients with combinations of one, two, or three of seven individual NEXUS Chest CT criteria. Across the 11 study sites, rates of chest CT performance ranged from 15.5% to 77.2% (median = 43.6%). We found injuries in 1,493/5,169 patients (28.9%) who had chest CT; 269 patients (5.2%) had major clinical injury (e.g., pneumothorax requiring chest tube). With sensitivity of 73.7 (95% confidence interval [CI] = 68.1 to 78.6) and specificity of 83.9 (95% CI = 83.6 to 84.2) for major clinical injury, abnormal chest-x-ray (CXR) was the single most important screening criterion. When patients had only abnormal CXR, injury and major clinical injury prevalences were 60.7% (95% CI = 52.2% to 68.6%) and 12.9% (95% CI = 8.3% to 19.4%), respectively. Injury and major clinical injury prevalences when any other single criterion alone (other than abnormal CXR) was present were 16.8% (95% CI = 15.2% to 18.6%) and 1.1% (95% CI = 0.1% to 1.8%), respectively. Injury and major clinical injury prevalences

Anteroposterior chest radiograph vs. chest CT scan in early detection of pneumothorax in trauma patients

OpenAIRE

Omar, Hesham R; Mangar, Devanand; Khetarpal, Suneel; Shapiro, David H; Kolla, Jaya; Rashad, Rania; Helal, Engy; Camporesi, Enrico M

2011-01-01

Abstract Pneumothorax is a common complication following blunt chest wall trauma. In these patients, because of the restrictions regarding immobilization of the cervical spine, Anteroposterior (AP) chest radiograph is usually the most feasible initial study which is not as sensitive as the erect chest X-ray or CT chest for detection of a pneumothorax. We will present 3 case reports which serve for better understanding of the entity of occult pneumothorax. The first case is an example of a tru...

Analysis the findings of chest radiograph and CT scan in 217 acute thoracic trauma

International Nuclear Information System (INIS)

Huang Shaoying

2005-01-01

Objective: To evaluate chest radiograph and CT scan in assessing acute thoracic trauma. Methods: Retrospectively analyzed the findings of chest radiograph and CT scan in 217 cases of acute thoracic trauma and positive rate of each modality was compared. Results: The positive rate of rib and clavicle fracture was higher in chest radiograph than these in CT scan. But the positive rate of chest wall hematoma, mediastinum and subcutaneous emphysema, pneumothorax, hydropneumothorax, damage of lung parenchyma and traumatic pulmonary atelectasis was higher in CT scan than those in chest radiograph. Conclusion: The application of the combined imaging modalities improves assessing of acute thoracic trauma, because the imaging manifestation of the lesion is various. (authors)

Computer-aided detection (CAD) of solid pulmonary nodules in chest x-ray equivalent ultralow dose chest CT - first in-vivo results at dose levels of 0.13 mSv

Energy Technology Data Exchange (ETDEWEB)

Messerli, Michael, E-mail: Michael.Messerli@usz.ch [Division of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen (Switzerland); Kluckert, Thomas; Knitel, Meinhard [Division of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen (Switzerland); Rengier, Fabian [Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg (Germany); Warschkow, René [Department of Surgery, Cantonal Hospital St. Gallen (Switzerland); Alkadhi, Hatem [Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University Zurich (Switzerland); Leschka, Sebastian [Division of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen (Switzerland); Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University Zurich (Switzerland); Wildermuth, Simon; Bauer, Ralf W. [Division of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen (Switzerland)

2016-12-15

Highlights: • Computer-aided detection (CAD) of solid pulmonary nodules was compared in 202 patients in standard dose and ultralow dose CT. • The per–nodule sensitivity of CAD was 70% in standard dose CT and 68% in ultralow dose CT. • The per–nodule sensitivity of CAD in standard dose CT was similar to ultralow dose CT in all size subgroups (all p > 0.05). • Adding CAD markings in ultralow dose CT significantly improved the sensitivity of two radiologists from 77% to 88% and from 66% to 79%, respectively. • CAD can serve as an excellent second reader for nodule detection in CT even at dose levels similar to chest X-ray. - Abstract: Objectives: To determine the value of computer-aided detection (CAD) for solid pulmonary nodules in ultralow radiation dose single-energy computed tomography (CT) of the chest using third-generation dual-source CT at 100 kV and fixed tube current at 70 mAs with tin filtration. Methods: 202 consecutive patients undergoing clinically indicated standard dose chest CT (1.8 ± 0.7 mSv) were prospectively included and scanned with an additional ultralow dose CT (0.13 ± 0.01 mSv) in the same session. Standard of reference (SOR) was established by consensus reading of standard dose CT by two radiologists. CAD was performed in standard dose and ultralow dose CT with two different reconstruction kernels. CAD detection rate of nodules was evaluated including subgroups of different nodule sizes (<5, 5–7, >7 mm). Sensitivity was further analysed in multivariable mixed effects logistic regression. Results: The SOR included 279 solid nodules (mean diameter 4.3 ± 3.4 mm, range 1–24 mm). There was no significant difference in per–nodule sensitivity of CAD in standard dose with 70% compared to 68% in ultralow dose CT both overall and in different size subgroups (all p > 0.05). CAD led to a significant increase of sensitivity for both radiologists reading the ultralow dose CT scans (all p < 0.001). In multivariable analysis, the use

Computer-aided detection (CAD) of solid pulmonary nodules in chest x-ray equivalent ultralow dose chest CT - first in-vivo results at dose levels of 0.13 mSv

International Nuclear Information System (INIS)

Messerli, Michael; Kluckert, Thomas; Knitel, Meinhard; Rengier, Fabian; Warschkow, René; Alkadhi, Hatem; Leschka, Sebastian; Wildermuth, Simon; Bauer, Ralf W.

2016-01-01

Highlights: • Computer-aided detection (CAD) of solid pulmonary nodules was compared in 202 patients in standard dose and ultralow dose CT. • The per–nodule sensitivity of CAD was 70% in standard dose CT and 68% in ultralow dose CT. • The per–nodule sensitivity of CAD in standard dose CT was similar to ultralow dose CT in all size subgroups (all p > 0.05). • Adding CAD markings in ultralow dose CT significantly improved the sensitivity of two radiologists from 77% to 88% and from 66% to 79%, respectively. • CAD can serve as an excellent second reader for nodule detection in CT even at dose levels similar to chest X-ray. - Abstract: Objectives: To determine the value of computer-aided detection (CAD) for solid pulmonary nodules in ultralow radiation dose single-energy computed tomography (CT) of the chest using third-generation dual-source CT at 100 kV and fixed tube current at 70 mAs with tin filtration. Methods: 202 consecutive patients undergoing clinically indicated standard dose chest CT (1.8 ± 0.7 mSv) were prospectively included and scanned with an additional ultralow dose CT (0.13 ± 0.01 mSv) in the same session. Standard of reference (SOR) was established by consensus reading of standard dose CT by two radiologists. CAD was performed in standard dose and ultralow dose CT with two different reconstruction kernels. CAD detection rate of nodules was evaluated including subgroups of different nodule sizes (<5, 5–7, >7 mm). Sensitivity was further analysed in multivariable mixed effects logistic regression. Results: The SOR included 279 solid nodules (mean diameter 4.3 ± 3.4 mm, range 1–24 mm). There was no significant difference in per–nodule sensitivity of CAD in standard dose with 70% compared to 68% in ultralow dose CT both overall and in different size subgroups (all p > 0.05). CAD led to a significant increase of sensitivity for both radiologists reading the ultralow dose CT scans (all p < 0.001). In multivariable analysis, the use

Diagnostic modalities x-ray and CT chest differ in the management of thoracic injury

Directory of Open Access Journals (Sweden)

D Chapagain

2015-06-01

Full Text Available Objective: To observe difference in the management of blunt trauma to the chest on the basis of conventional xray and computerised tomography of the chest. Methods: This prospective study was conducted between December 2011 to October 2012 in COMS in Bharatpur,a tertiary referral centre in central Nepal . Clinically stable thoracic injury patients were first evaluated with chest x-ray and the management on this basis was recorded. The findings of the CT chest were assessed and the type of management on the basis of CT was also recorded. Outcome was assessed in terms of mortality, morbidity, hospital and ICU stay with respect to the management on the basis of chest x-ray and CT scan. Results: Of the 129 patients, 74.4% were male and 25.6% were female with the patients ranging in age from 7 to 87 years (mean = 40.41 years. The most common mechanism of trauma to the chest was as a result of a motor vehicle accident (69.8%, followed by fall injury (20.2%. X-ray chest diagnosed rib fracture in 62%, haemothorax in 37%, pneumothorax in 27%, lung contusion in 10% and haemopneumothorax in 21% patients. Similarly CT chest diagnosed rib fracture in 86%, haemothorax in 54%, pneumothorax in 36%, lung contusion in 30% and haemopneumothorax in 30% patients. Mean hospital stay was 9.5 days in the group of patients having management on the basis of x-ray chest relative to mean stay of 10.2 days in the CT- chest group. In the management on the basis of xray group, there was a mean ICU stay of 2.8days compared to mean stays of 3.2 days in CT chest group. Conclusion: Though CT scan of the chest is more informative and differs the management of the blunt chest trauma, one should not forget to advise the cost effective, easily available and initial guiding agent, xray chest for early management of the chest injury patient. DOI: http://dx.doi.org/10.3126/jcmsn.v10i1.12764 Journal of College of Medical Sciences-Nepal, 2014, Vol.10(1; 22-31

What is the clinical significance of chest CT when the chest x-ray result is normal in patients with blunt trauma?

Science.gov (United States)

Kea, Bory; Gamarallage, Ruwan; Vairamuthu, Hemamalini; Fortman, Jonathan; Lunney, Kevin; Hendey, Gregory W; Rodriguez, Robert M

2013-08-01

Computed tomography (CT) has been shown to detect more injuries than plain radiography in patients with blunt trauma, but it is unclear whether these injuries are clinically significant. This study aimed to determine the proportion of patients with normal chest x-ray (CXR) result and injury seen on CT and abnormal initial CXR result and no injury on CT and to characterize the clinical significance of injuries seen on CT as determined by a trauma expert panel. Patients with blunt trauma older than 14 years who received emergency department chest imaging as part of their evaluation at 2 urban level I trauma centers were enrolled. An expert trauma panel a priori classified thoracic injuries and subsequent interventions as major, minor, or no clinical significance. Of 3639 participants, 2848 (78.3%) had CXR alone and 791 (21.7%) had CXR and chest CT. Of 589 patients who had chest CT after a normal CXR result, 483 (82.0% [95% confidence interval [CI], 78.7-84.9%]) had normal CT results, and 106 (18.0% [95% CI, 15.1%-21.3%]) had CTs diagnosing injuries-primarily rib fractures, pulmonary contusion, and incidental pneumothorax. Twelve patients had injuries classified as clinically major (2.0% [95% CI, 1.2%-3.5%]), 78 were clinically minor (13.2% [95% CI, 10.7%-16.2%]), and 16 were clinically insignificant (2.7% (95% CI, 1.7%-4.4%]). Of 202 patients with CXRs suggesting injury, 177 (87.6% [95% CI, 82.4%-91.5%]) had chest CTs confirming injury and 25 (12.4% [95% CI, 8.5%-17.6%]) had no injury on CT. Chest CT after a normal CXR result in patients with blunt trauma detects injuries, but most do not lead to changes in patient management. Copyright © 2013 Elsevier Inc. All rights reserved.

Clinical value of CARE dose 4D technique in decreasing CT scanning dose of adult chest

International Nuclear Information System (INIS)

Wu Aiqin; Zheng Wenlong; Xu Chongyong; Fang Bidong; Ge Wen

2011-01-01

Objective: To investigate the value of CARE Dose 4D technique in decreasing radiation dose and improving image quality of multi-slice spiral CT in adult chest scanning. Methods: 100 patients of chest CT scanning were equally divided into study group and control group randomly. CARE Dose 4D Technique was used in study group. Effective mAs value, volume CT dose index (CTDI vol ) and dose length product (DLP) were displayed automatically in machine while chest scanning; those values and actual mAs value of every image were recorded respectively. The image quality at apex of lung, lower edge of aorta arch, middle area of left atrium and base of lung on every image of 400 images was judged and classified as three level (excellent, good, poor) by two deputy chief physicians with double blind method, the image noise at corresponding parts was measured. Results: While setting 80 mAs for quality reference mAs, the effective mAs value in study group most decreased 44 mAs than control group with an average decrease of 9.60 (12.0%), CTDI vol with 4.75 mGy with an average decrease of 0.95 mCy (11.0%), DLP 99.50% in study group, with 98.0% in control group. But it was higher at apex of lung and base of lung, lower at middle area of left atrium, and similar at lower edge of aorta arch in study group than contrast group. The image noise were lower at apex of lung and base of lung in study group than control group (t =6.299 and 2.332, all P<0.05), higher at middle area of left atrium in study group than control group (t=3.078, P<0.05) and similar at lower edge of aorta arch in study group than control group (t=1.191, P>0.05). Conclusions: CARE Dose 4D technique provides a function regulated mAs real-time on line, it not only raises utilization rate of radiation and decreases radiation dose, but also promises and increases image quality in chest CT scanning, and has some clinical significance. (authors)

An education and training programme for radiological institutes: impact on the reduction of the CT radiation dose

International Nuclear Information System (INIS)

Schindera, Sebastian T.; Allmen, Gabriel von; Vock, Peter; Szucs-Farkas, Zsolt; Treier, Reto; Trueb, Philipp R.; Nauer, Claude

2011-01-01

To establish an education and training programme for the reduction of CT radiation doses and to assess this programme's efficacy. Ten radiological institutes were counselled. The optimisation programme included a small group workshop and a lecture on radiation dose reduction strategies. The radiation dose used for five CT protocols (paranasal sinuses, brain, chest, pulmonary angiography and abdomen) was assessed using the dose-length product (DLP) before and after the optimisation programme. The mean DLP values were compared with national diagnostic reference levels (DRLs). The average reduction of the DLP after optimisation was 37% for the sinuses (180 vs. 113 mGycm, P < 0.001), 9% for the brain (982 vs. 896 mGycm, P < 0.05), 24% for the chest (425 vs. 322 mGycm, P < 0.05) and 42% for the pulmonary arteries (352 vs. 203 mGycm, P < 0.001). No significant change in DLP was found for abdominal CT. The post-optimisation DLP values of the sinuses, brain, chest, pulmonary arteries and abdomen were 68%, 10%, 20%, 55% and 15% below the DRL, respectively. The education and training programme for radiological institutes is effective in achieving a substantial reduction in CT radiation dose. (orig.)

Lung nodule detection by microdose CT versus chest radiography (standard and dual-energy subtracted).

Science.gov (United States)

Ebner, Lukas; Bütikofer, Yanik; Ott, Daniel; Huber, Adrian; Landau, Julia; Roos, Justus E; Heverhagen, Johannes T; Christe, Andreas

2015-04-01

The purpose of this study was to investigate the feasibility of microdose CT using a comparable dose as for conventional chest radiographs in two planes including dual-energy subtraction for lung nodule assessment. We investigated 65 chest phantoms with 141 lung nodules, using an anthropomorphic chest phantom with artificial lung nodules. Microdose CT parameters were 80 kV and 6 mAs, with pitch of 2.2. Iterative reconstruction algorithms and an integrated circuit detector system (Stellar, Siemens Healthcare) were applied for maximum dose reduction. Maximum intensity projections (MIPs) were reconstructed. Chest radiographs were acquired in two projections with bone suppression. Four blinded radiologists interpreted the images in random order. A soft-tissue CT kernel (I30f) delivered better sensitivities in a pilot study than a hard kernel (I70f), with respective mean (SD) sensitivities of 91.1%±2.2% versus 85.6%±5.6% (p=0.041). Nodule size was measured accurately for all kernels. Mean clustered nodule sensitivity with chest radiography was 45.7%±8.1% (with bone suppression, 46.1%±8%; p=0.94); for microdose CT, nodule sensitivity was 83.6%±9% without MIP (with additional MIP, 92.5%±6%; pmicrodose CT for readers 1, 2, 3, and 4 were 84.3%, 90.7%, 68.6%, and 45.0%, respectively. Sensitivities with chest radiography for readers 1, 2, 3, and 4 were 42.9%, 58.6%, 36.4%, and 90.7%, respectively. In the per-phantom analysis, respective sensitivities of microdose CT versus chest radiography were 96.2% and 75% (pmicrodose CT, the applied dose was 0.1323 mSv. Microdose CT is better than the combination of chest radiography and dual-energy subtraction for the detection of solid nodules between 5 and 12 mm at a lower dose level of 0.13 mSv. Soft-tissue kernels allow better sensitivities. These preliminary results indicate that microdose CT has the potential to replace conventional chest radiography for lung nodule detection.

Community-Acquired Pneumonia Visualized on CT Scans but Not Chest Radiographs: Pathogens, Severity, and Clinical Outcomes.

Science.gov (United States)

Upchurch, Cameron P; Grijalva, Carlos G; Wunderink, Richard G; Williams, Derek J; Waterer, Grant W; Anderson, Evan J; Zhu, Yuwei; Hart, Eric M; Carroll, Frank; Bramley, Anna M; Jain, Seema; Edwards, Kathryn M; Self, Wesley H

2018-03-01

The clinical significance of pneumonia visualized on CT scan in the setting of a normal chest radiograph is uncertain. In a multicenter prospective surveillance study of adults hospitalized with community-acquired pneumonia (CAP), we compared the presenting clinical features, pathogens present, and outcomes of patients with pneumonia visualized on a CT scan but not on a concurrent chest radiograph (CT-only pneumonia) and those with pneumonia visualized on a chest radiograph. All patients underwent chest radiography; the decision to obtain CT imaging was determined by the treating clinicians. Chest radiographs and CT images were interpreted by study-dedicated thoracic radiologists blinded to the clinical data. The study population included 2,251 adults with CAP; 2,185 patients (97%) had pneumonia visualized on chest radiography, whereas 66 patients (3%) had pneumonia visualized on CT scan but not on concurrent chest radiography. Overall, these patients with CT-only pneumonia had a clinical profile similar to those with pneumonia visualized on chest radiography, including comorbidities, vital signs, hospital length of stay, prevalence of viral (30% vs 26%) and bacterial (12% vs 14%) pathogens, ICU admission (23% vs 21%), use of mechanical ventilation (6% vs 5%), septic shock (5% vs 4%), and inhospital mortality (0 vs 2%). Adults hospitalized with CAP who had radiological evidence of pneumonia on CT scan but not on concurrent chest radiograph had pathogens, disease severity, and outcomes similar to patients who had signs of pneumonia on chest radiography. These findings support using the same management principles for patients with CT-only pneumonia and those with pneumonia seen on chest radiography. Copyright © 2017 American College of Chest Physicians. All rights reserved.

Techniques and radiation dose in CT examinations of adult patients

International Nuclear Information System (INIS)

Elameen, S. E. A.

2010-06-01

The use of CT in medical diagnosis delivers radiation dose to patients that are higher than those from other radiological procedures. Lake of optimized protocols could be an additional source of increased dose. The aim of this study was to measure radiation doses in CT examination of the adults in three Sudanese hospitals. Details were obtained from approximately 160 CT examination carried out in 3 hospitals (3 CT scanners). Effective dose was calculated for each examination using CT dose indices. exposure related parameters and CT D1- to- effective dose conversion factors. CT air kerma index (CT D1) and dose length products (DLP) determined were below the established international reference dose levels. The mean effective doses in this study for the head, chest, and abdomen are 0.82, 3.7 and 5.4 mGy respectively. These values were observed that the effective dose per examination was lower in Sudan than in other countries. The report of a CT survey done in these centers indicates that the mean DLP values for adult patients were ranged from 272-460 mGy cm (head) 195-995 mGy cm (chest), 270-459 mGy cm (abdomen). There are a number of observed parameters that greatly need optimization, such as minimize the scan length, without missing any vital anatomical regions, modulation of exposure parameters (kV, mA, exposure time, and slice thickness) based on patient size and age. Another possible method is through use of contrast media only to optimize diagnostic yield. The last possible method is the use of radio protective materials for protection however, in order to achieve the above optimization strategies: there is great demand to educate CT personnel on the effects of scan parameter settings on radiation dose to patients and image quality required for accurate diagnosis. (Author)

Automatic radiation dose monitoring for CT of trauma patients with different protocols: feasibility and accuracy

International Nuclear Information System (INIS)

Higashigaito, K.; Becker, A.S.; Sprengel, K.; Simmen, H.-P.; Wanner, G.; Alkadhi, H.

2016-01-01

Aim: To demonstrate the feasibility and accuracy of automatic radiation dose monitoring software for computed tomography (CT) of trauma patients in a clinical setting over time, and to evaluate the potential of radiation dose reduction using iterative reconstruction (IR). Materials and methods: In a time period of 18 months, data from 378 consecutive thoraco-abdominal CT examinations of trauma patients were extracted using automatic radiation dose monitoring software, and patients were split into three cohorts: cohort 1, 64-section CT with filtered back projection, 200 mAs tube current–time product; cohort 2, 128-section CT with IR and identical imaging protocol; cohort 3, 128-section CT with IR, 150 mAs tube current–time product. Radiation dose parameters from the software were compared with the individual patient protocols. Image noise was measured and image quality was semi-quantitatively determined. Results: Automatic extraction of radiation dose metrics was feasible and accurate in all (100%) patients. All CT examinations were of diagnostic quality. There were no differences between cohorts 1 and 2 regarding volume CT dose index (CTDI_v_o_l; p=0.62), dose–length product (DLP), and effective dose (ED, both p=0.95), while noise was significantly lower (chest and abdomen, both −38%, p<0.017). Compared to cohort 1, CTDI_v_o_l, DLP, and ED in cohort 3 were significantly lower (all −25%, p<0.017), similar to the noise in the chest (–32%) and abdomen (–27%, both p<0.017). Compared to cohort 2, CTDI_v_o_l (–28%), DLP, and ED (both –26%) in cohort 3 was significantly lower (all, p<0.017), while noise in the chest (+9%) and abdomen (+18%) was significantly higher (all, p<0.017). Conclusion: Automatic radiation dose monitoring software is feasible and accurate, and can be implemented in a clinical setting for evaluating the effects of lowering radiation doses of CT protocols over time. - Highlights: • Automatic dose monitoring software can be

CT fluoroscopy-guided vs. multislice CT biopsy mode-guided lung biopsies: Accuracy, complications and radiation dose

International Nuclear Information System (INIS)

Prosch, Helmut; Stadler, Alfred; Schilling, Matthias; Bürklin, Sandra; Eisenhuber, Edith; Schober, Ewald; Mostbeck, Gerhard

2012-01-01

Background: The aim of this retrospective study was to compare the diagnostic accuracy, the frequency of complications, the duration of the interventions and the radiation doses of CT fluoroscopy (CTF) guided biopsies of lung lesions with those of multislice CT (MS-CT) biopsy mode-guided biopsies. Methods: Data and images from 124 consecutive patients undergoing CTF-guided lung biopsy (group A) and 132 MS-CT-biopsy mode-guided lung biopsy (group B) were reviewed. CTF-guided biopsies were performed on a Siemens Emotion 6 CT scanner with intermittent or continuous CT-fluoroscopy, MS-CT biopsy mode-guided biopsies were performed on a Siemens Emotion 16 CT scanner. All biopsies were performed with a coaxial needle technique. Results: The two groups (A vs. B) did not differ significantly regarding sensitivity (95.5% vs. 95.9%), specificity (96.7% vs. 95.5%), negative predictive value (87.9% vs. 84%) or positive predictive value (98.8% vs. 98.9%). Pneumothorax was observed in 30.0% and 32.5% of the patients, respectively. Chest tube placement was necessary in 4% (group A) and 13% (group B) of the patients. The duration of the intervention was significantly longer in group A (median 37 min vs. 32 min, p = 0.04). The mean CT dose index (CTDI) was 422 in group A and 36.3 in group B (p < 0.001). Conclusion: Compared to CTF-guided biopsies, chest biopsies using the MS-CT biopsy mode show dramatically lower CTDI levels. Although the diagnostic yield of the procedures do not differ significantly, biopsies using the MS-CT-biopsy mode have a three-fold higher rate of chest tube placement.

Predictors of abnormal chest CT after blunt trauma: a critical appraisal of the literature

International Nuclear Information System (INIS)

Brink, M.; Kool, D.R.; Dekker, H.M.; Deunk, J.; Jager, G.J.; Kuijk, C. van; Edwards, M.J.R.; Blickman, J.G.

2009-01-01

Aim: To identify and to evaluate predictors that determine whether chest computed tomography (CT) is likely to reveal relevant injuries in adult blunt trauma patients. Methods: After a comprehensive literature search for original studies on blunt chest injury diagnosis, two independent observers included studies on the accuracy of parameters derived from history, physical examination, or diagnostic imaging that might predict injuries at (multidetector row) CT in adults and that allowed construction of 2 x 2 contingency tables. For each article, methodological quality was scored and relevant predictors for injuries at CT were extracted. For each predictor, sensitivity, specificity, positive and negative likelihood ratio and diagnostic odds ratio (DOR) including 95% confidence intervals were calculated. Results: Of 147 articles initially identified, the observers included 10 original studies in consensus. Abnormalities at physical examination (abnormal respiratory effort, need for assisted ventilation, reduced airentry, coma, chest wall tenderness) and pelvic fractures were significant predictors (DOR: 2.1-6.7). The presence of any injuries at conventional radiography of the chest (eight articles) was a more powerful significant predictor (DOR: 2.2-37). Abnormal chest ultrasonography (four articles) was the most accurate predictor for chest injury at CT (DOR: 491-infinite). Conclusion: The current literature indicates that in blunt trauma patients with abnormal physical examination, abnormal conventional radiography, or abnormal ultrasonography of the chest, CT was likely to reveal relevant chest injuries. However, there was no strong evidence to suggest that CT could be omitted in patients without these criteria, or whether these findings are beneficial for patients

The Beatles, the Nobel Prize, and CT scanning of the chest.

Science.gov (United States)

Goodman, Lawrence R

2010-01-01

From its first test scan on a mouse, in 1967, to current medical practice, the CT scanner has become a core imaging tool in thoracic diagnosis. Initially financed by money from Beatles' record sales, the first patient scan was performed in 1971. Only 8 years later, a Nobel Prize in Physics and Medicine was awarded to Hounsfield and Cormack for their discovery. This article traces the history of CT scanner development and how each technical advance expanded chest diagnostic frontiers. Chest imaging now accounts for 30% of all CT scanning.

The forgotten view: Chest X-ray - Lateral view

Directory of Open Access Journals (Sweden)

Abraham M. Ittyachen

2017-01-01

Full Text Available With CT (computed tomography chest gaining more importance as a diagnostic tool, chest X-ray especially the lateral view is taken less commonly nowadays. Besides CT chest is also proven to be superior to chest X-ray in patients with major blunt trauma. We are presenting a 68-year old male who was partially treated from outside for a left sided pneumonia. He came to our hospital because of persisting chest pain. Chest X-ray, frontal view (postero-anterior was almost normal except for a mild opacity in the left lower zone. CT scan of the chest revealed a fluid collection posteriorly enclosed within enhancing pleura. Chest X-ray, left lateral view showed a corresponding posterior pleural based opacity. We are presenting this case to highlight the importance of the lateral view of the chest X-ray. In selected cases there is still a role for the lateral view. With the three dimensional visualization provided by the CT, the lateral view of the chest may be easier to understand. Consequent to the initial diagnosis by CT further follow up can be done with the chest X-ray. In a limited way this mitigates unnecessary expenditure and more importantly prevents the patient from exposure to harmful radiation in the form of repeated CT.

Effect of radiation dose level on the detectability of pulmonary nodules in chest tomosynthesis.

Science.gov (United States)

Asplund, Sara A; Johnsson, Åse A; Vikgren, Jenny; Svalkvist, Angelica; Flinck, Agneta; Boijsen, Marianne; Fisichella, Valeria A; Månsson, Lars Gunnar; Båth, Magnus

2014-07-01

To investigate the detectability of pulmonary nodules in chest tomosynthesis at reduced radiation dose levels. Eighty-six patients were included in the study and were examined with tomosynthesis and computed tomography (CT). Artificial noise was added to simulate that the tomosynthesis images were acquired at dose levels corresponding to 12, 32, and 70% of the default setting effective dose (0.12 mSv). Three observers (with >20, >20 and three years of experience) read the tomosynthesis cases for presence of nodules in a free-response receiver operating characteristics (FROC) study. CT served as reference. Differences between dose levels were calculated using the jack-knife alternative FROC (JAFROC) figure of merit (FOM). The JAFROC FOM was 0.45, 0.54, 0.55, and 0.54 for the 12, 32, 70, and 100% dose levels, respectively. The differences in FOM between the 12% dose level and the 32, 70, and 100% dose levels were 0.087 (p = 0.006), 0.099 (p = 0.003), and 0.093 (p = 0.004), respectively. Between higher dose levels, no significant differences were found. A substantial reduction from the default setting dose in chest tomosynthesis may be possible. In the present study, no statistically significant difference in detectability of pulmonary nodules was found when reducing the radiation dose to 32%. • A substantial radiation dose reduction in chest tomosynthesis may be possible. • Pulmonary nodule detectability remained unchanged at 32% of the effective dose. • Tomosynthesis might be performed at the dose of a lateral chest radiograph.

Cardiac CT for the assessment of chest pain: Imaging techniques and clinical results

International Nuclear Information System (INIS)

Becker, Hans-Christoph; Johnson, Thorsten

2012-01-01

Immediate and efficient risk stratification and management of patients with acute chest pain in the emergency department is challenging. Traditional management of these patients includes serial ECG, laboratory tests and further on radionuclide perfusion imaging or ECG treadmill testing. Due to the advances of multi-detector CT technology, dedicated coronary CT angiography provides the potential to rapidly and reliably diagnose or exclude acute coronary artery disease. Life-threatening causes of chest pain, such as aortic dissection and pulmonary embolism can simultaneously be assessed with a single scan, sometimes referred to as “triple rule out” scan. With appropriate patient selection, cardiac CT can accurately diagnose heart disease or other sources of chest pain, markedly decrease health care costs, and reliably predict clinical outcomes. This article reviews imaging techniques and clinical results for CT been used to evaluate patients with chest pain entering the emergency department.

Automated image quality assessment for chest CT scans.

Science.gov (United States)

Reeves, Anthony P; Xie, Yiting; Liu, Shuang

2018-02-01

Medical image quality needs to be maintained at standards sufficient for effective clinical reading. Automated computer analytic methods may be applied to medical images for quality assessment. For chest CT scans in a lung cancer screening context, an automated quality assessment method is presented that characterizes image noise and image intensity calibration. This is achieved by image measurements in three automatically segmented homogeneous regions of the scan: external air, trachea lumen air, and descending aorta blood. Profiles of CT scanner behavior are also computed. The method has been evaluated on both phantom and real low-dose chest CT scans and results show that repeatable noise and calibration measures may be realized by automated computer algorithms. Noise and calibration profiles show relevant differences between different scanners and protocols. Automated image quality assessment may be useful for quality control for lung cancer screening and may enable performance improvements to automated computer analysis methods. © 2017 American Association of Physicists in Medicine.

Patient-specific dose estimation for pediatric chest CT

Energy Technology Data Exchange (ETDEWEB)

Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P. [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27710 (United States); and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Global Applied Science Laboratory, GE Healthcare, Waukesha, Wisconsin 53188 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham North Carolina 27710 (United States)

2008-12-15

Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15 years old) and do not reflect the variability of patient anatomy and body habitus within the same size/age group. In this investigation, full-body computer models of seven pediatric patients in the same size/protocol group (weight: 11.9-18.2 kg) were created based on the patients' actual multi-detector array CT (MDCT) data. Organs and structures in the scan coverage were individually segmented. Other organs and structures were created by morphing existing adult models (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. Organ and effective dose of these patients from a chest MDCT scan protocol (64 slice LightSpeed VCT scanner, 120 kVp, 70 or 75 mA, 0.4 s gantry rotation period, pitch of 1.375, 20 mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated to simulate radiation transport in the same CT system. The seven patients had normalized effective dose of 3.7-5.3 mSv/100 mAs (coefficient of variation: 10.8%). Normalized lung dose and heart dose were 10.4-12.6 mGy/100 mAs and 11.2-13.3 mGy/100 mAs, respectively. Organ dose variations across the patients were generally small for large organs in the scan coverage (<7%), but large for small organs in the scan coverage (9%-18%) and for partially or indirectly exposed organs (11%-77%). Normalized effective dose correlated weakly with body weight (correlation coefficient: r=-0.80). Normalized lung dose and heart dose correlated strongly with mid-chest equivalent diameter (lung: r=-0.99, heart: r=-0.93); these strong correlation relationships can be used to estimate patient-specific organ

CT chest under general anesthesia: pulmonary, anesthetic and radiologic dilemmas

International Nuclear Information System (INIS)

Mahmoud, Mohamed; Towe, Christopher; Fleck, Robert J.

2015-01-01

Today's practice of medicine involves ever more complex patients whose care is coordinated with multidisciplinary teams. Caring for these patients can challenge all members of the health care team. Sedation/anesthesia in infants/toddlers as well as uncooperative or intellectually or emotionally impaired children who require imaging studies of the chest are ongoing challenges. High-quality computed tomography (CT) chest imaging studies in children under general anesthesia are extremely important for accurate interpretation and subsequent medical decision-making. Anesthesia-induced atelectasis may obscure or mimic true pathology creating a significant quality issue. Obtaining a high-quality, motion-free chest imaging study in infants and children under general anesthesia remains a difficult task in many institutions. Meticulous attention to anesthesia and imaging techniques and specialized knowledge are required to properly perform and interpret chest imaging studies. In this commentary, we discuss the continuous struggle to obtain high-quality CT chest imaging under general anesthesia. We will also discuss the major concerns of the anesthesiologist, radiologist and pulmonologist and why cooperation and coordination among these providers are critical for an optimal quality study.

CT chest under general anesthesia: pulmonary, anesthetic and radiologic dilemmas

Energy Technology Data Exchange (ETDEWEB)

Mahmoud, Mohamed [Cincinnati Children' s Hospital Medical Center, Department of Anesthesiology, Cincinnati, OH (United States); Towe, Christopher [Cincinnati Children' s Hospital Medical Center, Department of Pulmonary Medicine, Cincinnati, OH (United States); Fleck, Robert J. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

2015-07-15

Today's practice of medicine involves ever more complex patients whose care is coordinated with multidisciplinary teams. Caring for these patients can challenge all members of the health care team. Sedation/anesthesia in infants/toddlers as well as uncooperative or intellectually or emotionally impaired children who require imaging studies of the chest are ongoing challenges. High-quality computed tomography (CT) chest imaging studies in children under general anesthesia are extremely important for accurate interpretation and subsequent medical decision-making. Anesthesia-induced atelectasis may obscure or mimic true pathology creating a significant quality issue. Obtaining a high-quality, motion-free chest imaging study in infants and children under general anesthesia remains a difficult task in many institutions. Meticulous attention to anesthesia and imaging techniques and specialized knowledge are required to properly perform and interpret chest imaging studies. In this commentary, we discuss the continuous struggle to obtain high-quality CT chest imaging under general anesthesia. We will also discuss the major concerns of the anesthesiologist, radiologist and pulmonologist and why cooperation and coordination among these providers are critical for an optimal quality study.

Awareness of radiation exposure of thoracic CT scans and conventional radiographs: what do non-radiologists know?

International Nuclear Information System (INIS)

Heyer, C.M.; Peters, S.; Lemburg, S.; Nicolas, V.

2007-01-01

Purpose: Assessment of the knowledge of non-radiological physicians concerning radiation exposure during radiological procedures on the thorax. Material and Methods: 124 non-radiological physicians from the departments of surgery, internal medicine, anesthesiology, and neurology at a university hospital were questioned during a four-week period using a standardized questionnaire as to the effective dose (ED) of different radiological procedures on the thorax. The interviewees were asked to estimate the ED of chest X-rays and CT examinations and to compare these with the ED of other radiological methods. Length of professional experience, field of clinical training, and hierarchical position were also documented. The T-test and chi-square test were used for statistical analysis. Results: 119/124 (96.0 %) physicians with an average work experience of 8.2 years (0.3 - 32 years) were willing to participate. 47/119 (39.5 %) correctly estimated the ED of conventional chest X-ray (0.01 - 0.1 mSv), and 40/119 (33.6 %) correctly gauged the ED of adult chest CT (1 - 10 mSv). The ED of cardiac CT and pediatric chest CT without dose reduction (10 - 100 mSv) were correctly judged by 31/119 (26.1 %) and 32/119 (26.9 %), respectively. The correct ratio of the ED of chest X-ray to that of chest CT (factor 100 - 1000) was given by 28/119 (23.5 %), while 86/119 (72.3 %) underestimated the ratio. 50/119 (42.0 %) and 35/119 (29.4 %) correctly stated that the ED of pediatric chest CT without dose reduction and that of cardiac CT are greater than that of adult chest CT. 24/119 (20.2 %) and 10/119 (8.4 %) thought that the ED of low-dose chest CT is smaller than that of chest X-ray or chest MRI, respectively. The length of professional experience, field of clinical training, and hierarchical position of the participants did not have a significant influence on the test results. (orig.)

Utility of CT scan for the diagnosis of chest wall tuberculosis

Energy Technology Data Exchange (ETDEWEB)

Khalil, A.; Le Breton, C.; Tassart, M.; Korzec, J.; Bigot, J.M.; Carette, M.F. [Department of Radiology, Tenon Hospital, Paris (France)

1999-10-01

The objective of this study was to determine the utility of CT scan findings for the diagnosis of chest wall tuberculosis, excluding the spine. We reviewed 15 patients (13 Africans and 2 Indians) with chest wall tuberculosis, retrospectively. The radiologic examination consisted of a plain X-ray and a CT scan of the chest for each patient. The site of disease was the rib in 13 patients or the body of the sternum in 2 patients. One rib was involved in 11 patients, 2 contiguous ribs (one site) in 2 patients, and bilateral disease (two sites) was observed in the remaining patient. The 14 rib sites involved the posterior arc or costovertebral joint in 11 cases, the anterior arc in 2 cases, and the anterior and middle arc in 1 case. The CT scan findings were an abscess (n = 14) or a soft tissue mass (n = 2), osteolytic lesions (n = 13), periosteal reaction (n = 10), and sequestrum (n = 14). Bone sclerosis was observed only in 3 cases of rib involvement. The association of a soft tissue abscess, an osteolytic lesion, and sequestrum, especially in immigrants to France, suggests chest wall tuberculosis on CT scan. (orig.) With 5 figs., 2 tabs., 11 refs.

Radiation doses during chest examinations using dose modulation techniques in multislice CT scanner

International Nuclear Information System (INIS)

Livingstone, Roshan S.; Pradip, Joe; Dinakran, Paul M.; Srikanth, B.

2010-01-01

Objectives: To evaluate the radiation dose and image quality using a manual protocol and dose modulation techniques in a 6-slice CT scanner. Materials and Methods: Two hundred and twenty-one patients who underwent contrast-enhanced CT of the chest were included in the study. For the manual protocol settings, constant tube potential (kV) and tube current-time product (mAs) of 140 kV and 120 mAs, respectively, were used. The angular and z-axis dose modulation techniques utilized a constant tube potential of 140 kV; mAs values were automatically selected by the machine. Effective doses were calculated using dose-length product (DLP) values and the image quality was assessed using the signal-to-noise (SNR) ratio values. Mean effective doses using manual protocol for patients of weights 40-60 kg, 61-80 kg, and 81 kg and above were 8.58 mSv, 8.54 mSv, and 9.07 mSv, respectively. Mean effective doses using z-axis dose modulation for patients of weights 40-60 kg, 61-80 kg, and 81 kg and above were 4.95 mSv, 6.87 mSv, and 10.24 mSv, respectively. The SNR at the region of the liver for patients of body weight of 40-60 kg was 5.1 H, 6.2 H, and 8.8 H for manual, angular, and z-axis dose modulation, respectively. Conclusion: Dose reduction of up to 15% was achieved using angular dose modulation and of up to 42% using z-axis dose modulation, with acceptable diagnostic image quality compared to the manual protocol. (author)

Findings chest radiograph and CT in mediastinitis: effcacy of CT in patients with delayed diagnosis

Energy Technology Data Exchange (ETDEWEB)

Son, Eun Ju; Hong, Yong Kook; Choe, Kyu Ok [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

1999-01-01

To analyse the causes the radiologic findings in patients with mediastinitis and to evaluate the efficacy of chest CT scanning in patients with delayed diagnosis. Seventeen patients with histopathologically(n=15) or clinically diagnosed(n=2) mediastinitis were involved in this study. Eleven of the former group underwent surgery, and in four, tube drainage was performed. All underwent chest radiography and CT scanning, and in seven patients, the causes of delayed diagnosis were analysed. The most common cause of mediastinitis was esophageal rupture(n=11). Others were extension from neck abscess to the mediastinum(n=3), complications after a Benthall procedure(n=1), tuberculous lymphadenitis(n=1) and mycotic aneurysm(n=1). Patients with esophageal rupture suffered from underlying diseases such as esophageal cancer(n=2), iatrogenic esophageal rupture(n=2), Boerhaave's syndrome(n=2), and esophagitis(n=1). In patients with neck abscess (n=3), each was secondary to infected cystic hygroma, Ludwig angina, or deep neck infection, respectively. On chest CT, patients with esophageal rupture(n=11) had an abscess in the posterior mediastinum ; nine abscesses extended to the cervical area along the retropharyngeal space, and the patient with Ludwig angina had an abscess involving all compartments of the mediastinum. Among the total of 17 patients, diagnostic delays were found in seven, while five had spontaneous esophageal ruptures and two suffered complications after a Benthall procedure and Tbc lymphadenitis, respectively. The causes of diagnostic delay varied. Among seven patients, pnevmonia was initially diagnosed in two, who were treated ; one had multiorgan failure, and one was suffering from pericardial effusion and lung abscess. In three other patients, chest radiographs initially showed non-specific findings, leading to delayed CT examination. The most common cause of mediastinitis was esophageal rupture, and in these patients, chest radiographs and clinical

Findings chest radiograph and CT in mediastinitis: effcacy of CT in patients with delayed diagnosis

International Nuclear Information System (INIS)

Son, Eun Ju; Hong, Yong Kook; Choe, Kyu Ok

1999-01-01

To analyse the causes the radiologic findings in patients with mediastinitis and to evaluate the efficacy of chest CT scanning in patients with delayed diagnosis. Seventeen patients with histopathologically(n=15) or clinically diagnosed(n=2) mediastinitis were involved in this study. Eleven of the former group underwent surgery, and in four, tube drainage was performed. All underwent chest radiography and CT scanning, and in seven patients, the causes of delayed diagnosis were analysed. The most common cause of mediastinitis was esophageal rupture(n=11). Others were extension from neck abscess to the mediastinum(n=3), complications after a Benthall procedure(n=1), tuberculous lymphadenitis(n=1) and mycotic aneurysm(n=1). Patients with esophageal rupture suffered from underlying diseases such as esophageal cancer(n=2), iatrogenic esophageal rupture(n=2), Boerhaave's syndrome(n=2), and esophagitis(n=1). In patients with neck abscess (n=3), each was secondary to infected cystic hygroma, Ludwig angina, or deep neck infection, respectively. On chest CT, patients with esophageal rupture(n=11) had an abscess in the posterior mediastinum ; nine abscesses extended to the cervical area along the retropharyngeal space, and the patient with Ludwig angina had an abscess involving all compartments of the mediastinum. Among the total of 17 patients, diagnostic delays were found in seven, while five had spontaneous esophageal ruptures and two suffered complications after a Benthall procedure and Tbc lymphadenitis, respectively. The causes of diagnostic delay varied. Among seven patients, pnevmonia was initially diagnosed in two, who were treated ; one had multiorgan failure, and one was suffering from pericardial effusion and lung abscess. In three other patients, chest radiographs initially showed non-specific findings, leading to delayed CT examination. The most common cause of mediastinitis was esophageal rupture, and in these patients, chest radiographs and clinical symptoms

Case report: Pulmonary syphilis mimicking pulmonary hematogenous metastases on chest CT and integrated PET/CT

International Nuclear Information System (INIS)

Kim, Hyung Jun; Seon, Hyun Ju; Shin, Hyo Hyun; Choi, Yoo-Duk

2011-01-01

We report a case of syphilis with pulmonary involvement. Chest CT scan and 18 F-fluorodeoxyglucose (FDG) PET/CT showed multiple pulmonary nodules mimicking pulmonary hematogenous metastases. This was confirmed on follow-up images that showed therapeutic response to penicillin

Coronary calcium screening with dual-source CT: reliability of ungated, high-pitch chest CT in comparison with dedicated calcium-scoring CT

Energy Technology Data Exchange (ETDEWEB)

Hutt, Antoine; Faivre, Jean-Baptiste; Remy, Jacques; Remy-Jardin, Martine [CHRU et Universite de Lille, Department of Thoracic Imaging, Hospital Calmette (EA 2694), Lille (France); Duhamel, Alain; Deken, Valerie [CHRU et Universite de Lille, Department of Biostatistics (EA 2694), Lille (France); Molinari, Francesco [Centre Hospitalier General de Tourcoing, Department of Radiology, Tourcoing (France)

2016-06-15

To investigate the reliability of ungated, high-pitch dual-source CT for coronary artery calcium (CAC) screening. One hundred and eighty-five smokers underwent a dual-source CT examination with acquisition of two sets of images during the same session: (a) ungated, high-pitch and high-temporal resolution acquisition over the entire thorax (i.e., chest CT); (b) prospectively ECG-triggered acquisition over the cardiac cavities (i.e., cardiac CT). Sensitivity and specificity of chest CT for detecting positive CAC scores were 96.4 % and 100 %, respectively. There was excellent inter-technique agreement for determining the quantitative CAC score (ICC = 0.986). The mean difference between the two techniques was 11.27, representing 1.81 % of the average of the two techniques. The inter-technique agreement for categorizing patients into the four ranks of severity was excellent (weighted kappa = 0.95; 95 % CI 0.93-0.98). The inter-technique differences for quantitative CAC scores did not correlate with BMI (r = 0.05, p = 0.575) or heart rate (r = -0.06, p = 0.95); 87.2 % of them were explained by differences at the level of the right coronary artery (RCA: 0.8718; LAD: 0.1008; LCx: 0.0139; LM: 0.0136). Ungated, high-pitch dual-source CT is a reliable imaging mode for CAC screening in the conditions of routine chest CT examinations. (orig.)

Detection of pulmonary metastatic nodules: usefulness of low-dose multidetector CT in comparison with chest radiograph

International Nuclear Information System (INIS)

Kim, Ki Nam; Lee, Ki Nam; Yang, Doo Kyung; Lee, Soo Keol

2006-01-01

We wanted to evaluate the usefulness of low-dose multidetector CT for the detection and follow-up of pulmonary metastatic nodules in patients suffering with malignancy. We retrospectively reviewed the conventional chest radiographs and low-dose multidetector CT (low-dose CT) scans of 81 patients who had been under the diagnosis of malignancy. We reviewed the detection of pulmonary nodules and we counted the number of nodules detected by each method. The nodules were confirmed by surgical operation and by the radiologic criteria. The accuracy, sensitivity, specificity and positive and negative predictive values of each method for detecting metastatic nodules were compared with χ 2 tests. Low-dose CT depicted more nodules than did chest radiograph, and the indeterminate nodules seen on chest radiograph may be clearly benign on low-dose CT (eg. calcified granulomas or bony lesions). The accuracy of low-dose CT (75.3%) was significantly higher than that of chest radiograph (49.4%) for the detection for metastatic nodules (ρ < 0.05). Low-dose CT may provide better information than does chest radiograph for diagnosing pulmonary metastasis

Case report: Pulmonary syphilis mimicking pulmonary hematogenous metastases on chest CT and integrated PET/CT

Directory of Open Access Journals (Sweden)

Hyung Jun Kim

2011-01-01

Full Text Available We report a case of syphilis with pulmonary involvement. Chest CT scan and 18 F-fluorodeoxyglucose (FDG PET/CT showed multiple pulmonary nodules mimicking pulmonary hematogenous metastases. This was confirmed on follow-up images that showed therapeutic response to penicillin.

The significance of collateral vessels, as seen on chest CT, in predicting SVC obstruction

International Nuclear Information System (INIS)

Yeouk, Young Soo; Kim, Sung Jin; Bae, Il Hun; Kim, Jae Youn; Hwang, Seung Min; Han, Gi Seok; Park, Kil Sun; Kim, Dae Young

1998-01-01

To evaluate the significance of collateral veins, as seen on chest CT, in the diagnosis of superior vena cava obstruction. We retrospectively the records of 81 patients in whom collateral veins were seen on chest CT. On spiral CT(n=49), contrast material was infused via power injector, and on conventional CT(n=32), 50 ml bolus infusion was followed by 50 ml drip infusion. Obstruction of the SVC was evaluated on chest CT; if, however, evaluation of the SVC of its major tributaries was difficult, as in five cases, the patient underwent SVC phlebography. Collateral vessels were assigned to one of ten categories. On conventional CT, the jugular venous arch in the only collateral vessel to predict SVC obstruction; on spiral CT, however, collateral vessels are not helpful in the diagnosis of SVC obstruction, but are a nonspecific finding. (author). 12 refs., 2 tab., 2 figs

Reducing Radiation Doses in Female Breast and Lung during CT Examinations of Thorax: A new Technique in two Scanners

Directory of Open Access Journals (Sweden)

Mehnati P.

2017-09-01

Full Text Available Background: Chest CT is a commonly used examination for the diagnosis of lung diseases, but a breast within the scanned field is nearly never the organ of interest. Objective: The purpose of this study is to compare the female breast and lung doses using split and standard protocols in chest CT scanning. Materials and Methods: The sliced chest and breast female phantoms were used. CT exams were performed using a single-slice (SS- and a 16 multi-slice (MS- CT scanner at 100 kVp and 120 kVp. Two different protocols, including standard and split protocols, were selected for scanning. The breast and lung doses were measured using thermo-luminescence dosimeters which were inserted into different layers of the chest and breast phantoms. The differences in breast and lung radiation doses in two protocols were studied in two scanners, analyzed by SPSS software and compared by t-test. Results: Breast dose by split scanning technique reduced 11% and 31% in SS- and MS- CT. Also, the radiation dose of lung tissue in this method decreased 18% and 54% in SS- and MS- CT, respectively. Moreover, there was a significant difference (p< 0.0001 in the breast and lung radiation doses between standard and split scanning protocols. Conclusion: The application of a split scan technique instead of standard protocol has a considerable potential to reduce breast and lung doses in SS- and MS- CT scanners. If split scanning protocol is associated with an optimum kV and MSCT, the maximum dose decline will be provided.

Regional variance of visually lossless threshold in compressed chest CT images: Lung versus mediastinum and chest wall

International Nuclear Information System (INIS)

Kim, Tae Jung; Lee, Kyoung Ho; Kim, Bohyoung; Kim, Kil Joong; Chun, Eun Ju; Bajpai, Vasundhara; Kim, Young Hoon; Hahn, Seokyung; Lee, Kyung Won

2009-01-01

Objective: To estimate the visually lossless threshold (VLT) for the Joint Photographic Experts Group (JPEG) 2000 compression of chest CT images and to demonstrate the variance of the VLT between the lung and mediastinum/chest wall. Subjects and methods: Eighty images were compressed reversibly (as negative control) and irreversibly to 5:1, 10:1, 15:1 and 20:1. Five radiologists determined if the compressed images were distinguishable from their originals in the lung and mediastinum/chest wall. Exact tests for paired proportions were used to compare the readers' responses between the reversible and irreversible compressions and between the lung and mediastinum/chest wall. Results: At reversible, 5:1, 10:1, 15:1, and 20:1 compressions, 0%, 0%, 3-49% (p < .004, for three readers), 69-99% (p < .001, for all readers), and 100% of the 80 image pairs were distinguishable in the lung, respectively; and 0%, 0%, 74-100% (p < .001, for all readers), 100%, and 100% were distinguishable in the mediastinum/chest wall, respectively. The image pairs were less frequently distinguishable in the lung than in the mediastinum/chest wall at 10:1 (p < .001, for all readers) and 15:1 (p < .001, for two readers). In 321 image comparisons, the image pairs were indistinguishable in the lung but distinguishable in the mediastinum/chest wall, whereas there was no instance of the opposite. Conclusion: For JPEG2000 compression of chest CT images, the VLT is between 5:1 and 10:1. The lung is more tolerant to the compression than the mediastinum/chest wall.

Regional variance of visually lossless threshold in compressed chest CT images: Lung versus mediastinum and chest wall

Energy Technology Data Exchange (ETDEWEB)

Kim, Tae Jung [Department of Radiology, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707 (Korea, Republic of); Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University Medical Research Center (Korea, Republic of); Lee, Kyoung Ho [Department of Radiology, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707 (Korea, Republic of); Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University Medical Research Center (Korea, Republic of)], E-mail: kholee@snubhrad.snu.ac.kr; Kim, Bohyoung; Kim, Kil Joong; Chun, Eun Ju; Bajpai, Vasundhara; Kim, Young Hoon [Department of Radiology, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707 (Korea, Republic of); Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University Medical Research Center (Korea, Republic of); Hahn, Seokyung [Medical Research Collaborating Center, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul 110-744 (Korea, Republic of); Seoul National University College of Medicine (Korea, Republic of); Lee, Kyung Won [Department of Radiology, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707 (Korea, Republic of); Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University Medical Research Center (Korea, Republic of)

2009-03-15

Objective: To estimate the visually lossless threshold (VLT) for the Joint Photographic Experts Group (JPEG) 2000 compression of chest CT images and to demonstrate the variance of the VLT between the lung and mediastinum/chest wall. Subjects and methods: Eighty images were compressed reversibly (as negative control) and irreversibly to 5:1, 10:1, 15:1 and 20:1. Five radiologists determined if the compressed images were distinguishable from their originals in the lung and mediastinum/chest wall. Exact tests for paired proportions were used to compare the readers' responses between the reversible and irreversible compressions and between the lung and mediastinum/chest wall. Results: At reversible, 5:1, 10:1, 15:1, and 20:1 compressions, 0%, 0%, 3-49% (p < .004, for three readers), 69-99% (p < .001, for all readers), and 100% of the 80 image pairs were distinguishable in the lung, respectively; and 0%, 0%, 74-100% (p < .001, for all readers), 100%, and 100% were distinguishable in the mediastinum/chest wall, respectively. The image pairs were less frequently distinguishable in the lung than in the mediastinum/chest wall at 10:1 (p < .001, for all readers) and 15:1 (p < .001, for two readers). In 321 image comparisons, the image pairs were indistinguishable in the lung but distinguishable in the mediastinum/chest wall, whereas there was no instance of the opposite. Conclusion: For JPEG2000 compression of chest CT images, the VLT is between 5:1 and 10:1. The lung is more tolerant to the compression than the mediastinum/chest wall.

CT angiography - chest

Science.gov (United States)

... your provider if you take the diabetes medication metformin (Glucophage). You may need to take extra precautions. ... Damage to kidneys from contrast dye CT scans use more radiation than regular x-rays. Having many ...

Effect of contrast material on image noise and radiation dose in adult chest computed tomography using automatic exposure control: A comparative study between 16-, 64- and 128-slice CT

Energy Technology Data Exchange (ETDEWEB)

Paul, Jijo, E-mail: jijopaul1980@gmail.com [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Haus 23C UG, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Goethe University, Department of Biophysics, Max von Laue-Strasse 1, 60438 Frankfurt am Main (Germany); Schell, Boris, E-mail: boris.schell@googlemail.com [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Haus 23C UG, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Kerl, J. Matthias, E-mail: matthias.kerl@gmai.com [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Haus 23C UG, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Maentele, Werner, E-mail: maentele@biophysik.uni-frankfurt.de [Goethe University, Department of Biophysics, Max von Laue-Strasse 1, 60438 Frankfurt am Main (Germany); Vogl, Thomas J., E-mail: t.vogl@em.uni-frankfurt.de [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Haus 23C UG, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Bauer, Ralf W., E-mail: ralfwbauer@aol.com [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Haus 23C UG, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany)

2011-08-15

Purpose: To determine the difference in radiation dose between non-enhanced (NECT) and contrast-enhanced (CECT) chest CT examinations contributed by contrast material with different scanner generations with automatic exposure control (AEC). Methods and materials: Each 42 adult patients received a NECT and CECT of the chest in one session on a 16-, 64- or 128-slice CT scanner with the same scan protocol settings. However, AEC technology (Care Dose 4D, Siemens) underwent upgrades in each of the three scanner generations. DLP, CTDIvol and image noise were compared. Results: Although absolute differences in image noise were very small and ranged between 10 and 13 HU for NECT and CECT in median, the differences in image noise and dose (DLP: 16-slice:+2.8%; 64-slice:+3.9%; 128-slice:+5.6%) between NECT and CECT were statistically significant in all groups. Image noise and dose parameters were significantly lower in the most recent 128-slice CT generation for both NECT and CECT (DLP: 16-slice:+35.5-39.2%; 64-slice:+6.8-8.5%). Conclusion: The presence of contrast material lead to an increase in dose for chest examinations in three CT generations with AEC. Although image noise values were significantly higher for CECT, the absolute differences were in a range of 3 HU. This can be regarded as negligible, thus indicating that AEC is able to fulfill its purpose of maintaining image quality. However, technological developments lead to a significant reduction of dose and image noise with the latest CT generation.

Simple pulmonary eosinophilia (loeffler's syndrome): chest radiographic and CT findings

Energy Technology Data Exchange (ETDEWEB)

Jung, Kyung Jae; Lee, Kyung Soo; Kim, Tae Sung; Chung, Man Pyo; Choi, Dong Chull; Kwon, O Jung [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

2000-01-01

The purpose of our study is to describe the chest radiographic and CT findings of simple pulmonary eosinophilia. Twenty-six patients with simple pulmonary eosinophilia underwent chest radiography and CT scanning; the results were analyzed retrospectively by two chest radiologists, focusing on the patterns and distribution of the parenchymal abnormalities. The chest radiographs were normal in eight patients (31%), while among the remaining 18 patients, they showed subtle opacity (n=3D9), nodules (n=3D8), consolidation (n=3D2), and mass (n=3D1). Follow-up chest radiographs (m=3D18) demonstrated complete (n=3D16) or partial (n=3D1) resolution of parenchymal lesions or migratory lesions (n=3D1). On CT, nodule(s) (n=3D19) were most commonly seen, followed by ground-glass opacity (n=3D16), consolidation (n=3D3), and mass (n=3D1). A peripheral halo surrounding a nodule or an area of consolidation was seen in 18 patients. The nodules(s) (n=3D19) were subpleural (n=3D13) or random (=3D6). Areas of ground-glass opacity (n=3D16) were subpleural (n=3D13), random (n=3D2), or central (n=3D1). All lesions were patchy rather than diffuse. Follow-up CT in nine patients showed complete (n=3D7) or partial (n=3D2) resolution of parenchymal lesions. Chest radiographs of patients with simple pulmonary eosinophilia often reveal no abnormality. The most common finding is subtle opacity or nodule(s), while CT reveals transient nodule(s) with a surrounding halo or transient areas of ground glass opacity. (author)

Chest CT findings in patients with non-cardiovascular causes of chest pain: Focusing on pulmonary tuberculosis in a tuberculosis endemic country

International Nuclear Information System (INIS)

Lee, So Won; Shim, Sung Shine; Kim, Yoo Kyung; Ryu, Yon Ju

2015-01-01

To review the common causes of non-cardiovascular chest pain (NCCP) according to the location and lesion type as seen on chest CT, and to evaluate CT findings in tuberculosis (TB) as a cause of NCCP. In the period 2009 to 2012, patients having NCCP without definitive evidence of acute myocardial infarction, pulmonary thromboembolism, and aortic dissection, were included. In total, 162 patients (60.5% male; 39.5% female), with a mean age of 51 years, were enrolled. CT images were evaluated by location and lesion type, for causes of NCCP. Chest CT revealed that the most common location for the cause of NCCP was the pleura (45.1%), followed by the subpleural lung parenchyma (30.2%). The most common lesion causing NCCP was TB (33.3%), followed by pneumonia (19.1%). Of the 54 TB cases, 40 (74.1%) were stable TB and 14 (25.9%) were active TB; among these 54 patients, NCCP was most commonly the result of fibrotic pleural thickening (55.6%), followed by subpleural stable pulmonary TB (14.8%). Results of chest CT revealed that TB was a major cause of NCCP in a TB endemic area. Among the TB patients, fibrotic pleural thickening in patients with stable TB was the most common cause of NCCP

Chest CT findings in patients with non-cardiovascular causes of chest pain: Focusing on pulmonary tuberculosis in a tuberculosis endemic country

Energy Technology Data Exchange (ETDEWEB)

Lee, So Won; Shim, Sung Shine; Kim, Yoo Kyung; Ryu, Yon Ju [Mokdong Hospital, Ewha Womans University School of Medicine, Seoul (Korea, Republic of)

2015-10-15

To review the common causes of non-cardiovascular chest pain (NCCP) according to the location and lesion type as seen on chest CT, and to evaluate CT findings in tuberculosis (TB) as a cause of NCCP. In the period 2009 to 2012, patients having NCCP without definitive evidence of acute myocardial infarction, pulmonary thromboembolism, and aortic dissection, were included. In total, 162 patients (60.5% male; 39.5% female), with a mean age of 51 years, were enrolled. CT images were evaluated by location and lesion type, for causes of NCCP. Chest CT revealed that the most common location for the cause of NCCP was the pleura (45.1%), followed by the subpleural lung parenchyma (30.2%). The most common lesion causing NCCP was TB (33.3%), followed by pneumonia (19.1%). Of the 54 TB cases, 40 (74.1%) were stable TB and 14 (25.9%) were active TB; among these 54 patients, NCCP was most commonly the result of fibrotic pleural thickening (55.6%), followed by subpleural stable pulmonary TB (14.8%). Results of chest CT revealed that TB was a major cause of NCCP in a TB endemic area. Among the TB patients, fibrotic pleural thickening in patients with stable TB was the most common cause of NCCP.

Multi-Detector CT Findings of Palpable Chest Wall Masses in Children: A Pictorial Essay

Energy Technology Data Exchange (ETDEWEB)

Park, Chan Ho; Kim, Young Tong [Dept. of Radiology, Soonchunhyang University College of Medicine, Cheonan Hospital, Cheonan (Korea, Republic of); Hong, Hyun Sook [Dept. of Radiology, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon (Korea, Republic of)

2013-03-15

A wide variety of diseases manifest as palpable chest wall masses in children. These include normal variation, congenital anomalies, trauma, infection, axillary lymphadenopathies, soft tissue tumors and bone tumors. Given that most of these diseases are associated with chest wall deformity, diagnosis is difficult by physical examination or ultrasonography alone. However, multi-detector CT with three dimensional reconstruction is useful in the characterization and differential diagnosis of palpable chest wall lesions. In this article, we review the spectrum of palpable chest wall diseases and illustrate their multi-detector CT presentation.

Patient doses in chest CT examinations: Comparison of various CT scanners

Directory of Open Access Journals (Sweden)

Božović Predrag

2013-01-01

Full Text Available This paper presents results from study on patient exposure level in chest CT examinations. CT scanners used in this study were various Siemens and General Electric (GE models. Data on patient doses were collected for adult and pediatric patients. Doses measured for adult patients were lower then those determined as Diagnostic Reference Levels (DRL for Europe, while doses for pediatric patients were similar to those found in published data. As for the manufactures, slightly higher doses were measured on GE devices, both for adult and pediatric patients.

Doses in pediatric patients undergoing chest and abdomen CT examinations. Preliminary results

International Nuclear Information System (INIS)

Jornada, Tiago S.; Silva, Teogenes A. da

2011-01-01

Computed tomography (CT) is a non-invasive method of image production that imparts significant doses to a patient, it is expected that pediatric CT examinations will increase the risk of induced cancer in children. In this study the effective doses in a five year-old child submitted to chest or abdomen CT scans were assessed for comparison purposes. The CTEXPO computed program was used with data from routine protocols of a 0 to 13 year-old children in two public hospitals in Belo Horizonte. Hospital A used a Siemens Dual-Slice unit with 80 kV, 41 mA and pitch 2 for chest or abdomen; hospital B used a Multislice GE unit with 120 kV, 45 mA and pitch 1 for chest and 120 kV, 55 mA. and pitch 1 for abdomen. Results of effective doses in a five year-old child were 1.7 and 1.0 mSv in hospital A and 9.1 and 7.2 mSv in hospital B, for chest and abdomen, respectively. Results were compared to the reference effective doses of 7.2 and 5.0 mSv for chest and abdomen respectively that were derived from the air kerma length product values given in ICRP publication 87. Results of hospital A showed that low dose exposures also can be achieved in CT scans of children. Results showed that even a hospital with a modern facility (hospital B) can provided doses higher than reference values if protocols are not adjusted for children. Preliminary results suggested that there is a room for optimizing children exposure submitted to CT scans. (author)

The relationship between image quality and CT dose index of multi-slice low-dose chest CT

International Nuclear Information System (INIS)

Zhu Xiaohua; Shao Jiang; Shi Jingyun; You Zhengqian; Li Shijun; Xue Yongming

2003-01-01

Objective: To explore the rationality and possibility of multi-slice low-dose CT scan in the examination of the chest. Methods: (1) X-ray dose index measurement: 120 kV tube voltage, 0.75 s rotation, 8 mm and 3 mm slice thickness, and the tube current setting of 115.0, 40.0, 25.0, and 7.5 mAs were employed in every section. The X-ray radiation dose was measured and compared statistically. (2) phantom measurement of homogeneity and noise: The technical parameters were 120 kV, 0.75 s, 8 mm and 3 mm sections, and every slice was scanned using tube current of 115.0, 40.0, 25.0, and 7.5 mAs. Five same regions of interest were measured on every image. The homogeneity and noise level of CT were appraised. (3) The multi-slice low-dose CT in patients: 30 patients with mass and 30 with patch shadow in the lung were selected randomly. The technical parameters were 120 kV, 0.75 s, 8 mm and 3 mm slice thickness. 115.0, 40.0, 25.0, 15.0, and 7.5 mAs tube current were employed in each same slice. Otherwise, 15 cases with helical scan were examined using 190, 150, 40, 25, and 15 mAs tube current. The reconstruction images of MIP, MPR, CVR, HRCT, 3D, CT virtual endoscopy, and variety of interval reconstruction were compared. (4) Evaluation of image quality: CT images were evaluated by four doctors using single-blind method, and 3 degrees including normal image, image with few artifact, and image with excessive artifact, were employed and analyzed statistically. Results: (1) The CT dose index with 115.0 mAs tube current exceeded those of 40.0, 25.0, and 7.5 mAs by about 60%, 70%, and 85%, respectively. (2) The phantom measurement showed that the lower of CT dose the lower of homogeneity, the lower of CT dose the higher of noise level. (3) Result of image quality evaluation: The percentage of the normal image had no significant difference between 8 and 3 mm in 115, 40, and 25 mAs (P>0.05). Conclusion: Multi-slice low-dose chest CT technology may protect the patients and guarantee the

Computer-aided segmentation system for 3D chest CT

International Nuclear Information System (INIS)

Iwasawa, Tae; Komagata, Takanobu; Ogura, Takashi; Iwao, Yuma; Goto, Toshiyuki; Asakura, Akira; Inoue, Tomio

2012-01-01

We will introduce the quantitative analysis of the chest CT images using computer-assisted segmentation system (Gaussian Histogram Normalized Correlation; GHNC). This system can divide the lung into several patterns, for example, normal, emphysema and fibrous lesion, and measure each lesion volume quantitatively. We analyzed 3D-CT images of 20 patients with lung cancer. GHNC could measure the volumes of emphysema and fibrosis lesions, respectively. GHNC analysis will be feasible for preoperative CT evaluation, especially in the patients with combined pulmonary fibrosis and emphysema. (author)

CT guided percutaneous needle biopsy of the chest: initial experience

African Journals Online (AJOL)

The objective of this article is to report our first experience of CT guided percutaneous thoracic biopsy and to demonstrate the accuracy and safety of this procedure. This was a retrospective study of 28 CT-Guided Percutaneous Needle Biopsies of the Chest performed on 24 patients between November 2014 and April 2015.

Cross-sectional imaging with CT and/or MRI of pediatric chest tumors

International Nuclear Information System (INIS)

Wyttenbach, R.; Vock, P.; Tschaeppeler, H.

1998-01-01

The purpose of this study was to provide an overview of the spectrum of pediatric chest masses, to present the results of cross-sectional imaging with CT and/or MRI, and to define diagnostic criteria to limit differential diagnosis. Seventy-eight children with thoracic mass lesions were retrospectively evaluated using CT (72 patients) and/or MR imaging (12 patients). All masses were evaluated for tissue characteristics (attenuation values or signal intensity, enhancement, and calcification) and were differentiated according to age, gender, location, and etiology. Twenty-eight of 38 (74 %) mediastinal masses were malignant (neuroblastoma, malignant lymphoma). Thirty of 38 (79 %) pulmonary masses were metastatic in origin, all with an already known primary tumor (osteosarcoma, Wilms tumor). With one exception, all remaining pulmonary lesions were benign. Seventeen of 21 (81 %) chest wall lesions were malignant (Ewing sarcoma, primitive neuroectodermal tumor). The majority of mediastinal and chest wall tumors in children is malignant. Lung lesions are usually benign, unless a known extrapulmonary tumor suggests pulmonary metastases. Cross-sectional imaging with CT and/or MRI allows narrowing of the differential diagnosis of pediatric chest masses substantially by defining the origin and tissue characteristics. Magnetic resonance imaging is preferred for posterior mediastinal lesions, whereas CT should be used for pulmonary lesions. For the residual locations both modalities are complementary. (orig.)

Radiation dosage of various CT-methods in lung diagnostics

International Nuclear Information System (INIS)

Heinz-Peer, G.; Weninger, F.; Nowotny, R.; Herold, C.J.

1996-01-01

Introduction of the computed tomography index CTDI and the multiple scan average dose (MSAD) has led to standardization of the dose description in CT examinations. Despite the use of these dose parameters, many different dosages are reported in the literature for different CT methods. In addition, there is still a wide range of radiation dosimetry results reported for conventional CT, helical CT, and HRCT used in chest examinations. The variations in dosage are mainly due to difference in factors affecting the dose, i.e. beam geometry, beam quality, scanner geometry ('generation'), and operating parameters. In addition, CT dosimetry instrumentation and methodology make a contribution to dosages. Recent studies calculating differences in factors affecting dosage and CT dosimetry and using similar operating parameters, show similar results in CT dosimetry for conventional and helical CT. On the other hand, dosages for HRCT were greatly reduced. This was mainly caused by narrow beam collimation and increasing section spacing. (orig.) [de

Intrapulmonary pseudo-malposition of chest tubes on computed tomography (CT)

International Nuclear Information System (INIS)

Flueckiger, F.; Kullnig, P.; Juettner-Smolle, F.; Melzer, G.; Graz Univ.

1991-01-01

The diagnosis of an intrapulmonary malposition of chest tubes on CT may be problematic. We report about 13 chest tubes which were suspected on CT to be in an intrapulmonary malposition. In all cases as well as clinical and radiological follow up ruled out such a malposition. The use of a stiff tube and the presence of a soft lung parenchyma obviously led to a sinking of the tube into a 'channel'. Whereas after removal of the tube in case of such a pseudo-malposition solely a transitory local fluid collection and later a tender scar is seen, real intrapumonary malposition leads to parenchymal injury and concomitant complications. The diagnosis of intrapulmonary malposition should be doubted, if the drain is positioned within the pleural space after having crossed the lung parenchyma in a supposed intrapulmonary rout. The CT criterias of this pseudo-malposition are presented and discussed. (orig.) [de

Combining automatic tube current modulation with adaptive statistical iterative reconstruction for low-dose chest CT screening.

Science.gov (United States)

Chen, Jiang-Hong; Jin, Er-Hu; He, Wen; Zhao, Li-Qin

2014-01-01

To reduce radiation dose while maintaining image quality in low-dose chest computed tomography (CT) by combining adaptive statistical iterative reconstruction (ASIR) and automatic tube current modulation (ATCM). Patients undergoing cancer screening (n = 200) were subjected to 64-slice multidetector chest CT scanning with ASIR and ATCM. Patients were divided into groups 1, 2, 3, and 4 (n = 50 each), with a noise index (NI) of 15, 20, 30, and 40, respectively. Each image set was reconstructed with 4 ASIR levels (0% ASIR, 30% ASIR, 50% ASIR, and 80% ASIR) in each group. Two radiologists assessed subjective image noise, image artifacts, and visibility of the anatomical structures. Objective image noise and signal-to-noise ratio (SNR) were measured, and effective dose (ED) was recorded. Increased NI was associated with increased subjective and objective image noise results (PASIR levels (PASIR had average subjective image noise scores and nearly average anatomical structure visibility scores, with a mean objective image noise of 23.42 HU. The EDs for groups 1, 2, 3 and 4 were 2.79 ± 1.17, 1.69 ± 0.59, 0.74 ± 0.29, and 0.37 ± 0.22 mSv, respectively. Compared to group 1 (NI = 15), the ED reductions were 39.43%, 73.48%, and 86.74% for groups 2, 3, and 4, respectively. Using NI = 30 with 50% ASIR in the chest CT protocol, we obtained average or above-average image quality but a reduced ED.

Selective chest imaging for blunt trauma patients: The national emergency X-ray utilization studies (NEXUS-chest algorithm).

Science.gov (United States)

Rodriguez, Robert M; Hendey, Gregory W; Mower, William R

2017-01-01

Chest imaging plays a prominent role in blunt trauma patient evaluation, but indiscriminate imaging is expensive, may delay care, and unnecessarily exposes patients to potentially harmful ionizing radiation. To improve diagnostic chest imaging utilization, we conducted 3 prospective multicenter studies over 12years to derive and validate decision instruments (DIs) to guide the use of chest x-ray (CXR) and chest computed tomography (CT). The first DI, NEXUS Chest x-ray, consists of seven criteria (Age >60years; rapid deceleration mechanism; chest pain; intoxication; altered mental status; distracting painful injury; and chest wall tenderness) and exhibits a sensitivity of 99.0% (95% confidence interval [CI] 98.2-99.4%) and a specificity of 13.3% (95% CI, 12.6%-14.0%) for detecting clinically significant injuries. We developed two NEXUS Chest CT DIs, which are both highly reliable in detecting clinically major injuries (sensitivity of 99.2%; 95% CI 95.4-100%). Designed primarily to focus on detecting major injuries, the NEXUS Chest CT-Major DI consists of six criteria (abnormal CXR; distracting injury; chest wall tenderness; sternal tenderness; thoracic spine tenderness; and scapular tenderness) and exhibits higher specificity (37.9%; 95% CI 35.8-40.1%). Designed to reliability detect both major and minor injuries (sensitivity 95.4%; 95% CI 93.6-96.9%) with resulting lower specificity (25.5%; 95% CI 23.5-27.5%), the NEXUS CT-All rule consists of seven elements (the six NEXUS CT-Major criteria plus rapid deceleration mechanism). The purpose of this review is to synthesize the three DIs into a novel, cohesive summary algorithm with practical implementation recommendations to guide selective chest imaging in adult blunt trauma patients. Copyright © 2016 Elsevier Inc. All rights reserved.

AP diameter shows the strongest correlation with CTDI and DLP in abdominal and chest CT.

LENUS (Irish Health Repository)

Zarb, Francis

2010-01-01

The purpose of this study is to investigate the relationships among cross-sectional diameters, weight and computed tomography (CT) dose descriptors (CTDI and DLP) to identify which is best used as a measure for the establishment of DRLs in CT. Data (gender, weight, cross-sectional diameters, dose descriptors) from 56 adult patients attending for either a CT examination of the abdomen or chest was obtained from two spiral CT units using automatic milliampere modulation. The AP diameter was demonstrated as the main contributing factor influencing the dose in CT (CTDI: r(2) = 0.269, p-value < or =0.001; DLP: r(2) = 0.260, p-value < or =0.001) since it has a greater correlation with radiation dose than body weight and can thus be its substitute in dose-reduction strategies and establishment of DRLs. The advantages of using the AP diameter are that it can easily be measured prior to scanning or retrospectively from previous CT images. However, further studies on the practicality of this approach are recommended.

Novel Influenza A (H1N1) Virus Infection in Children: Chest Radiographic and CT Evaluation

Energy Technology Data Exchange (ETDEWEB)

Choi, Min Jeong; Lee, Young Seok; Lee, Jee Young; Lee, Kun Song [Dankook University College of Medicine, Dankook University Hospital, Cheonan (Korea, Republic of)

2010-12-15

The purpose of this study was to evaluate the chest radiographic and CT findings of novel influenza A (H1N1) virus infection in children, the population that is more vulnerable to respiratory infection than adults. The study population comprised 410 children who were diagnosed with an H1N1 infection from August 24, 2009 to November 11, 2009 and underwent chest radiography at Dankook University Hospital in Korea. Six of these patients also underwent chest CT. The initial chest radiographs were classified as normal or abnormal. The abnormal chest radiographs and high resolution CT scans were assessed for the pattern and distribution of parenchymal lesions, and the presence of complications such as atelectasis, pleural effusion, and pneumomediastinum. The initial chest radiograph was normal in 384 of 410 (94%) patients and abnormal in 26 of 410 (6%) patients. Parenchymal abnormalities seen on the initial chest radiographs included prominent peribronchial marking (25 of 26, 96%), consolidation (22 of 26, 85%), and ground-glass opacities without consolidation (2 of 26, 8%). The involvement was usually bilateral (19 of 26, 73%) with the lower lung zone predominance (22 of 26, 85%). Atelectasis was observed in 12 (46%) and pleural effusion in 11 (42%) patients. CT (n = 6) scans showed peribronchovascular interstitial thickening (n = 6), ground-glass opacities (n = 5), centrilobular nodules (n = 4), consolidation (n = 3), mediastinal lymph node enlargement (n = 5), pleural effusion (n = 3), and pneumomediastinum (n = 3). Abnormal chest radiographs were uncommon in children with a swine-origin influenza A (H1N1) virus (S-OIV) infection. In children, H1N1 virus infection can be included in the differential diagnosis, when chest radiographs and CT scans show prominent peribronchial markings and ill-defined patchy consolidation with mediastinal lymph node enlargement, pleural effusion and pneumomediastinum

Novel Influenza A (H1N1) Virus Infection in Children: Chest Radiographic and CT Evaluation

International Nuclear Information System (INIS)

Choi, Min Jeong; Lee, Young Seok; Lee, Jee Young; Lee, Kun Song

2010-01-01

The purpose of this study was to evaluate the chest radiographic and CT findings of novel influenza A (H1N1) virus infection in children, the population that is more vulnerable to respiratory infection than adults. The study population comprised 410 children who were diagnosed with an H1N1 infection from August 24, 2009 to November 11, 2009 and underwent chest radiography at Dankook University Hospital in Korea. Six of these patients also underwent chest CT. The initial chest radiographs were classified as normal or abnormal. The abnormal chest radiographs and high resolution CT scans were assessed for the pattern and distribution of parenchymal lesions, and the presence of complications such as atelectasis, pleural effusion, and pneumomediastinum. The initial chest radiograph was normal in 384 of 410 (94%) patients and abnormal in 26 of 410 (6%) patients. Parenchymal abnormalities seen on the initial chest radiographs included prominent peribronchial marking (25 of 26, 96%), consolidation (22 of 26, 85%), and ground-glass opacities without consolidation (2 of 26, 8%). The involvement was usually bilateral (19 of 26, 73%) with the lower lung zone predominance (22 of 26, 85%). Atelectasis was observed in 12 (46%) and pleural effusion in 11 (42%) patients. CT (n = 6) scans showed peribronchovascular interstitial thickening (n = 6), ground-glass opacities (n = 5), centrilobular nodules (n = 4), consolidation (n = 3), mediastinal lymph node enlargement (n = 5), pleural effusion (n = 3), and pneumomediastinum (n = 3). Abnormal chest radiographs were uncommon in children with a swine-origin influenza A (H1N1) virus (S-OIV) infection. In children, H1N1 virus infection can be included in the differential diagnosis, when chest radiographs and CT scans show prominent peribronchial markings and ill-defined patchy consolidation with mediastinal lymph node enlargement, pleural effusion and pneumomediastinum

Posterior diaphragmatic defect detected on chest CT: the incidence according to age and the lateral chest radiographic appearances

International Nuclear Information System (INIS)

Lee, Son Youl; Choi, Yo Won; Jeon, Seok Chol; Heo, Jeong Nam; Park, Choong Ki

2007-01-01

We wanted to investigate the incidence of posterior diaphragmatic defect on chest CT in various age groups and its lateral chest radiographic appearances. The chest CT scans of 78 patients of various ages with posterior diaphragmatic defect were selected among 1,991 patients, and they were analyzed for the incidence of defect in various age groups, the defect location and the herniated contents. Their lateral chest radiographs were analyzed for the shape of the posterior diaphragm and the posterior costophrenic sulcus. The patients' ages ranged from 34 to 87 with the tendency of a higher incidence in the older patients. The defect most frequently involved the medial two thirds (n = 49, 50.4%) and middle one third (n = 36, 37%) of the posterior diaphragm. The retroperitoneal fat was herniated into the thorax through the defect in all patients, and sometimes with the kidney (n = 8). Lateral chest radiography showed a normal diaphragmatic contour (n = 51, 49.5%), blunting of the posterior costophrenic sulcus (n = 41, 39.8%), focal humping of the posterior diaphragm (n = 7, 6.8%), or upward convexity (n = 4, 3.9%) of the posterior costophrenic sulcus on the affected side. The posterior diaphragmatic defect discovered in asymptomatic patients who are without a history of peridiaphragmatic disease is most likely acquired, and this malady increases in incidence according to age. An abnormal contour of the posterior diaphragm or the costophrenic sulcus on a lateral chest radiograph may be a finding of posterior diaphragmatic defect

MRI of the Chest

Medline Plus

Full Text Available ... body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to evaluate various ... seen by other imaging modalities, such as chest x-ray or CT. A special form of MRI called ...

CT dose profiles and MSAD calculation in a chest phantom

International Nuclear Information System (INIS)

Oliveira, Bruno Beraldo; Silva, Teogenes Augusto da

2011-01-01

For optimizing patient doses in computed tomography (CT), the Brazilian legislation has only established diagnostic reference levels (DRLs) in terms of Multiple Scan Average Dose (MSAD) in a typical adult as a quality control parameter for CT scanners. Compliance with the DRLs can be verified by measuring the Computed Tomography Air Kerma Index with a calibrated pencil ionization chamber or by obtaining the dose distribution in CT scans. An analysis of the quality of five CT scanners in Belo Horizonte was done in terms of dose profile of chest scans and MSAD determinations. Measurements were done with rod shape lithium fluoride thermoluminescent dosimeters (TLD-100) distributed in cylinders positioned in peripheral and central regions of a polymethylmethacrylate chest phantom. The peripheral regions presented higher dose values. The longitudinal dose variation can be observed and the maximum dose was recorded at the edges of the phantom at the midpoint of the longitudinal axis. The MSAD results were in according to the DRL of 25 mGy established by Brazilian legislation. The results contribute to disseminate to hospitals and radiologists the proper procedure to use the thermoluminescent dosimeters for the calculation of the MSAD from the CT dose profiles and to notice the compliance with the DRLs. (author)

MRI of the Chest

Medline Plus

Full Text Available ... internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to evaluate various ... seen by other imaging modalities, such as chest x-ray or CT. A special form of MRI called ...

Diagnostic imaging in polytrauma: comparison of radiation exposure from whole-body MSCT and conventional radiography with organ-specific CT

International Nuclear Information System (INIS)

Wedegaertner, U.; Lorenzen, M.; Weber, C.; Adam, G.; Nagel, H.D.

2004-01-01

Purpose: To compare the radiation dose of whole-body multislice CT (MSCT) and conventional radiography with organ-specific CT in polytrauma. Materials and Methods: The whole-body MSCT encompassing brain, neck and midface, chest, abdomen and pelvis was performed on a Somatom Volume Zoom (Siemens). Conventional radiography consisted of chest and cervical, thoracic and lumbar spine in two views as well as pelvis. Polymat, Siemens. Three combinations of organ specific CT were chosen: CT examination of (1) head and cervical spine, (2) head, cervical spine and chest, (3) head, cervical spine and abdomen. The effective doses of whole-body MSCT and conventional radiography with organ-specific CT were calculated. Results: Effective doses were 20 mSv for whole-body MSCT, 2 mSv for conventional x-ray, and 5 mSv for combination (1), 8 mSv for combination (2) and (3) 16 mSv for combination (3) of the organ-specific CT. The ratio of radiation dose between whole-body MSCT and radiography was 10: 1. This ratio was reduced to 3: 1, 2: 1 and 1: 1 when a combination of radiography and CT was performed. Conclusions: Whole-body MSCT in polytrauma compared to conventional radiography with organ-specific CT induces a threefold increased dose in unfavorable situations and no increased dose in favorable situations. Nevertheless, routine use of whole-body MSCT should be critically evaluated and should be adapted to the clinical benefit. (orig.) [de

Measurement of radiation dose to ovaries from CT of the head and trunk

Energy Technology Data Exchange (ETDEWEB)

Al-Habdhan, M.A.M.; Kinsara, A.R. [King Abdul Aziz Univ., Nuclear Engineering Dept., Jeddah (Saudi Arabia)

2001-07-01

With the rise in concern about doses received by patients over recent years, there has been a growing requirement for information on typical doses and the range of dose received during Computerized Tomography (CT). This study was performed for the assessment of radiation dose to the ovaries from various CT protocols for head and trunk imaging. Thermo luminescent dosimeters (TLD) were used for the dosimetry measurement in an anthropomorphic Rando Alderson phantom. The wanted (obligatory) and unwanted (non-useful) radiation doses delivered to the ovaries during CT examinations of head, facial bone, orbits, abdomen, chest, pelvis, neck, nasopharynx, cervical spine, lumber spine and sacroiliac joint were assessed. The results are compared with the corresponding values published in the literature. A comparison of the received dose from CT examinations and general radiography examinations by the ovaries was made. It is found that relatively high doses of unwanted radiation are delivered with computerized tomography. (author)

Noncontrast chest computed tomography immediately after transarterial chemoembolization in patients with hepatocellular carcinoma: Clinical benefits and effect of radiation reduction on image quality in low-dose scanning

International Nuclear Information System (INIS)

Choi, Joon-Il; Kim, Hyun Beom; Kim, Min Ju; Lee, Jong Seok; Koh, Young Whan; An, Sang Bu; Ko, Heung-kyu; Park, Joong-Won

2011-01-01

Purpose: To evaluate the clinical benefits of noncontrast chest computed tomography (CT) immediately after transarterial chemoembolization in patients with hepatocellular carcinoma and to assess the effect of radiation reduction on image quality in low-dose scanning. Materials and methods: From June to October 2010, we performed standard-dose, noncontrast chest CTs immediately after transarterial chemoembolization in 160 patients and low-dose CTs in 88 patients. We reviewed the entire noncontrast chest CTs and follow-up CTs to reveal the clinical benefits of CT evaluation immediately after transarterial chemoembolization. Using two independent readers, we also retrospectively evaluated the radiation dose and image quality in terms of the image noise, contrast between the liver parenchyma and iodized oil and diagnostic acceptability for the evaluation of treatment response after transarterial chemoembolization. Results: In 5.2% of the patients, additional treatment was performed immediately after the interpretation of the noncontrast chest CT, and additional pulmonary lesions were found in 8.5% of the patients. The measured mean dose-length product for the low-dose scanning was 18.4% of that of the standard-dose scanning. The image noise was significantly higher with the low-dose scanning (p < 0.001). However, all of the low-dose CT scans were diagnostically acceptable, and the mean scores for the subjective assessments of the contrast and diagnostic acceptability showed no significant differences for either reader. Conclusion: A noncontrast chest CT immediately after transarterial chemoembolization has some clinical benefits for immediate decision making and detecting pulmonary lesions. Low-dose, noncontrast chest CTs immediately after transarterial chemoembolization consistently provide diagnostically acceptable images and information on treatment response in patients who have undergone transarterial chemoembolization.

Application of Super-Resolution Convolutional Neural Network for Enhancing Image Resolution in Chest CT.

Science.gov (United States)

Umehara, Kensuke; Ota, Junko; Ishida, Takayuki

2017-10-18

In this study, the super-resolution convolutional neural network (SRCNN) scheme, which is the emerging deep-learning-based super-resolution method for enhancing image resolution in chest CT images, was applied and evaluated using the post-processing approach. For evaluation, 89 chest CT cases were sampled from The Cancer Imaging Archive. The 89 CT cases were divided randomly into 45 training cases and 44 external test cases. The SRCNN was trained using the training dataset. With the trained SRCNN, a high-resolution image was reconstructed from a low-resolution image, which was down-sampled from an original test image. For quantitative evaluation, two image quality metrics were measured and compared to those of the conventional linear interpolation methods. The image restoration quality of the SRCNN scheme was significantly higher than that of the linear interpolation methods (p < 0.001 or p < 0.05). The high-resolution image reconstructed by the SRCNN scheme was highly restored and comparable to the original reference image, in particular, for a ×2 magnification. These results indicate that the SRCNN scheme significantly outperforms the linear interpolation methods for enhancing image resolution in chest CT images. The results also suggest that SRCNN may become a potential solution for generating high-resolution CT images from standard CT images.

Bicuspid aortic valves: Diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT

Energy Technology Data Exchange (ETDEWEB)

Murphy, David J., E-mail: david.murphy@st-vincents.ie [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); McEvoy, Sinead H., E-mail: s.mcevoy@st-vincents.ie [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); Iyengar, Sri, E-mail: sri.iyengar@nhs.net [Department of Radiology, Plymouth Hospitals NHS Trust, Plymouth Devon PL6 8DH (United Kingdom); Feuchtner, Gudrun, E-mail: Gudrun.Feuchtner@i-med.ac.at [Department of Radiology, Innsbruck Medical University, Anichstr. 35, A-6020 Innsbruck (Austria); Cury, Ricardo C., E-mail: r.cury@baptisthealth.net [Department of Radiology, Baptist Cardiac and Vascular Institute, 8900 North Kendall Drive, Miami, FL 33176 (United States); Roobottom, Carl, E-mail: carl.roobottom@nhs.net [Department of Radiology, Plymouth Hospitals NHS Trust, Plymouth Devon PL6 8DH (United Kingdom); Plymouth University Peninsula Schools of Medicine and Dentistry (United Kingdom); Baumueller, Stephan, E-mail: Hatem.Alkadhi@usz.ch [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich (Switzerland); Alkadhi, Hatem, E-mail: stephan.baumueller@usz.ch [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich (Switzerland); Dodd, Jonathan D., E-mail: jonniedodd@gmail.com [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland)

2014-08-15

Objectives: To assess the diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT for bicuspid aortic valves. Materials and methods: The standard axial chest CT scans of 20 patients with known bicuspid aortic valves were blindly, randomly analyzed for (i) the appearance of the valve cusps, (ii) the largest aortic sinus area, (iii) the longest aortic cusp length, (iv) the thickest aortic valve cusp and (v) valve calcification. A second blinded reader independently analyzed the appearance of the valve cusps. Forty-two age- and sex-matched patients with known tricuspid aortic valves were used as controls. Retrospectively ECG-gated cardiac CT multiphase reconstructions of the aortic valve were used as the gold-standard. Results: Fourteen (21%) scans were scored as unevaluable (7 bicuspid, 7 tricuspid). Of the remainder, there were 13 evaluable bicuspid valves, ten of which showed an aortic valve line sign, while the remaining three showed a normal Mercedes-Benz appearance owing to fused valve cusps. The 35 evaluable tricuspid aortic valves all showed a normal Mercedes-Benz appearance (P = 0.001). Kappa analysis = 0.62 indicating good interobserver agreement for the aortic valve cusp appearance. Aortic sinus areas, aortic cusp lengths and aortic cusp thicknesses of ≥3.8 cm{sup 2}, 3.2 cm and 1.6 mm respectively on standard axial chest CT best distinguished bicuspid from tricuspid aortic valves (P < 0.0001 for all). Of evaluable scans, the sensitivity, specificity, positive and negative predictive values of standard axial chest CT in diagnosing bicuspid aortic valves was 77% (CI 0.54–1.0), 100%, 100% and 70% respectively. Conclusion: The aortic valve is evaluable in approximately 80% of standard chest 64-slice CT scans. Bicuspid aortic valves may be diagnosed on evaluable scans with good diagnostic accuracy. An aortic valve line sign, enlarged aortic sinuses and elongated, thickened valve cusps are specific CT

Effect of radiation dose level on the detectability of pulmonary nodules in chest tomosynthesis

International Nuclear Information System (INIS)

Asplund, Sara A.; Svalkvist, Angelica; Maansson, Lars Gunnar; Baath, Magnus; Johnsson, Aase A.; Vikgren, Jenny; Flinck, Agneta; Boijsen, Marianne; Fisichella, Valeria A.

2014-01-01

To investigate the detectability of pulmonary nodules in chest tomosynthesis at reduced radiation dose levels. Eighty-six patients were included in the study and were examined with tomosynthesis and computed tomography (CT). Artificial noise was added to simulate that the tomosynthesis images were acquired at dose levels corresponding to 12, 32, and 70 % of the default setting effective dose (0.12 mSv). Three observers (with >20, >20 and three years of experience) read the tomosynthesis cases for presence of nodules in a free-response receiver operating characteristics (FROC) study. CT served as reference. Differences between dose levels were calculated using the jack-knife alternative FROC (JAFROC) figure of merit (FOM). The JAFROC FOM was 0.45, 0.54, 0.55, and 0.54 for the 12, 32, 70, and 100 % dose levels, respectively. The differences in FOM between the 12 % dose level and the 32, 70, and 100 % dose levels were 0.087 (p = 0.006), 0.099 (p = 0.003), and 0.093 (p = 0.004), respectively. Between higher dose levels, no significant differences were found. A substantial reduction from the default setting dose in chest tomosynthesis may be possible. In the present study, no statistically significant difference in detectability of pulmonary nodules was found when reducing the radiation dose to 32 %. (orig.)

Effect of radiation dose level on the detectability of pulmonary nodules in chest tomosynthesis

Energy Technology Data Exchange (ETDEWEB)

Asplund, Sara A.; Svalkvist, Angelica; Maansson, Lars Gunnar; Baath, Magnus [University of Gothenburg, Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg (Sweden); Sahlgrenska University Hospital, Department of Medical Physics and Biomedical Engineering, Gothenburg (Sweden); Johnsson, Aase A.; Vikgren, Jenny; Flinck, Agneta; Boijsen, Marianne; Fisichella, Valeria A. [University of Gothenburg, Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg (Sweden); Sahlgrenska University Hospital, Department of Radiology, Gothenburg (Sweden)

2014-07-15

To investigate the detectability of pulmonary nodules in chest tomosynthesis at reduced radiation dose levels. Eighty-six patients were included in the study and were examined with tomosynthesis and computed tomography (CT). Artificial noise was added to simulate that the tomosynthesis images were acquired at dose levels corresponding to 12, 32, and 70 % of the default setting effective dose (0.12 mSv). Three observers (with >20, >20 and three years of experience) read the tomosynthesis cases for presence of nodules in a free-response receiver operating characteristics (FROC) study. CT served as reference. Differences between dose levels were calculated using the jack-knife alternative FROC (JAFROC) figure of merit (FOM). The JAFROC FOM was 0.45, 0.54, 0.55, and 0.54 for the 12, 32, 70, and 100 % dose levels, respectively. The differences in FOM between the 12 % dose level and the 32, 70, and 100 % dose levels were 0.087 (p = 0.006), 0.099 (p = 0.003), and 0.093 (p = 0.004), respectively. Between higher dose levels, no significant differences were found. A substantial reduction from the default setting dose in chest tomosynthesis may be possible. In the present study, no statistically significant difference in detectability of pulmonary nodules was found when reducing the radiation dose to 32 %. (orig.)

CT radiation dose and image quality optimization using a porcine model.

Science.gov (United States)

Zarb, Francis; McEntee, Mark F; Rainford, Louise

2013-01-01

To evaluate potential radiation dose savings and resultant image quality effects with regard to optimization of commonly performed computed tomography (CT) studies derived from imaging a porcine (pig) model. Imaging protocols for 4 clinical CT suites were developed based on the lowest milliamperage and kilovoltage, the highest pitch that could be set from current imaging protocol parameters, or both. This occurred before significant changes in noise, contrast, and spatial resolution were measured objectively on images produced from a quality assurance CT phantom. The current and derived phantom protocols were then applied to scan a porcine model for head, abdomen, and chest CT studies. Further optimized protocols were developed based on the same methodology as in the phantom study. The optimization achieved with respect to radiation dose and image quality was evaluated following data collection of radiation dose recordings and image quality review. Relative visual grading analysis of image quality criteria adapted from the European guidelines on radiology quality criteria for CT were used for studies completed with both the phantom-based or porcine-derived imaging protocols. In 5 out of 16 experimental combinations, the current clinical protocol was maintained. In 2 instances, the phantom protocol reduced radiation dose by 19% to 38%. In the remaining 9 instances, the optimization based on the porcine model further reduced radiation dose by 17% to 38%. The porcine model closely reflects anatomical structures in humans, allowing the grading of anatomical criteria as part of image quality review without radiation risks to human subjects. This study demonstrates that using a porcine model to evaluate CT optimization resulted in more radiation dose reduction than when imaging protocols were tested solely on quality assurance phantoms.

Evaluation of variation of voltage (kV) absorbed dose in chest CT scans

International Nuclear Information System (INIS)

Mendonca, Bruna G.A.; Mourao, Arnaldo P.

2013-01-01

Computed tomography (CT) is one of the most important diagnostic techniques images today. The increasing utilization of CT implies a significant increase of population exposure to ionizing radiation. Optimization of practice aims to reduce doses to patients because the image quality is directly related to the diagnosis. You can decrease the amount of dose to the patient, and maintain the quality of the image. There are several parameters that can be manipulated in a CT scan and these parameters can be used to reduce the energy deposited in the patient. Based on this, we analyzed the variation of dose deposited in the lungs, breasts and thyroid, by varying the supply voltage of the tube. Scans of the thorax were performed following the protocol of routine chest with constant and variable current for the same applied voltage. Moreover, a female phantom was used and thermoluminescent dosimeters (TLD-100), model bat, were used to record the specific organ doses. Scans were performed on a GE CT scanner, model 64 Discovery channels. Higher doses were recorded for the voltage of 120 kV with 200 mAs in the lungs (22.46 mGy) and thyroid (32.22 mGy). For scans with automatic mAs, variable between 100 and 440, this same tension contributed to the higher doses. The best examination in terms of the dose that was used with automatic 80 kV mAs, whose lungs and thyroid received lower dose. For the best breast exam was 100 kV. Since the increase in the 80 kV to 100 kV no impact so much the dose deposited in the lungs, it can be concluded that lowering the applied voltage to 100 kV resulted in a reduction in the dose absorbed by the patient. These results can contribute to optimizing scans of the chest computed tomography

Performance of ultralow-dose CT with iterative reconstruction in lung cancer screening: limiting radiation exposure to the equivalent of conventional chest X-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Huber, Adrian [University Hospital Inselspital Bern, Department of Diagnostic, Interventional and Paediatric Radiology, Bern (Switzerland); University Hospital Pitie-Salpetriere, Department of Polyvalent and Oncological Radiology, Paris (France); Landau, Julia; Buetikofer, Yanik; Leidolt, Lars; Brela, Barbara; May, Michelle; Heverhagen, Johannes; Christe, Andreas [University Hospital Inselspital Bern, Department of Diagnostic, Interventional and Paediatric Radiology, Bern (Switzerland); Ebner, Lukas [University Hospital Inselspital Bern, Department of Diagnostic, Interventional and Paediatric Radiology, Bern (Switzerland); Duke University Medical Center, Department of Radiology, Durham, NC (United States)

2016-10-15

To investigate the detection rate of pulmonary nodules in ultralow-dose CT acquisitions. In this lung phantom study, 232 nodules (115 solid, 117 ground-glass) of different sizes were randomly distributed in a lung phantom in 60 different arrangements. Every arrangement was acquired once with standard radiation dose (100 kVp, 100 references mAs) and once with ultralow radiation dose (80 kVp, 6 mAs). Iterative reconstruction was used with optimized kernels: I30 for ultralow-dose, I70 for standard dose and I50 for CAD. Six radiologists examined the axial 1-mm stack for solid and ground-glass nodules. During a second and third step, three radiologists used maximum intensity projection (MIPs), finally checking with computer-assisted detection (CAD), while the others first used CAD, finally checking with the MIPs. The detection rate was 95.5 % with standard dose (DLP 126 mGy*cm) and 93.3 % with ultralow-dose (DLP: 9 mGy*cm). The additional use of either MIP reconstructions or CAD software could compensate for this difference. A combination of both MIP reconstructions and CAD software resulted in a maximum detection rate of 97.5 % with ultralow-dose. Lung cancer screening with ultralow-dose CT using the same radiation dose as a conventional chest X-ray is feasible. (orig.)

Aortic valve calcification - a commonly observed but frequently ignored finding during CT scanning of the chest.

Science.gov (United States)

Raju, Prashanth; Sallomi, David; George, Bindu; Patel, Hitesh; Patel, Nikhil; Lloyd, Guy

2012-06-01

To describe the frequency and severity of Aortic valve calcification (AVC) in an unselected cohort of patients undergoing chest CT scanning and to assess the frequency with which AVC was being reported in the radiology reports. Consecutive CT scan images of the chest and the radiological reports (December 2009 to May 2010) were reviewed at the district general hospital (DGH). AVC on CT scan was visually graded on a scale ranging from 0 to IV (0 = no calcification, IV = severe calcification). Total of 416 (232 male; 184 female) CT chest scans [Contrast enhanced 302 (72%), unenhanced 114 (28%)] were reviewed. Mean age was 70.55 ± 11.48 years. AVC in CT scans was identified in 95 of the 416 patients (22.83%). AVC classification was as follows: Grade I: 60 (63.15%), Grade II: 22 (23.15%), Grade III: 9 (9.47%), Grade IV: 4 (4.21%). Only one CT report mentioned AVC. Only 31 of 95 AVC had Transthoracic echocardiogram (TTE). The interval time between CT scan and TTE was variable.   Aortic valve calcification in CT chest scans is a common finding and studies have shown that it is strongly related to the presence and severity of aortic valve disease. As CT scans are considered as a valuable additional screening tool for detection of aortic stenosis, AVC should always be commented upon in the radiology reports. Furthermore, patients with at least Grade III and IV AVC should be sent for TTE. © 2012 Blackwell Publishing Ltd.

Increased opacity of left pericardiac area on chest radiograph : correlation with CT findings and its frequency

International Nuclear Information System (INIS)

Lee, Seung Ik; Kim, Jeung Sook; Kwak, Jin Young; Ryu, Chang Woo; Yoon, Sam Hyun

1998-01-01

The purpose of this study was to evaluate the incidence of extrapericardial fat in the left cardiac border, and with regard to left extrapericardial fat, to correlate chest radiographs with CT scans. This study involved 132 consecutive patients who underwent chest PA and lateral radiographs, and chest CT scans. According to the results of chest PA radiograph, patients were divided into three groups: those with a clear left cardiac border; those with an indistinct left cardiac border; and those with an indistinct left cardiac border with increased density; cardiophrenic angle, as seen on lateral radiograph, the presence of increased density in the anterior cardiophrenic angle, as seen on lateral radiographs was evaluated. On the basis of the results of CT scanning, patients were classified into four groups according to the amount of left extrapericardial fat : negative, minimum, moderate, and maximum. Left extrapericardial fat, as seen on CT, was correlated with the conspicuity of left cardiac border seen on PA radiograph and the presence of increased density in the anterior cardiophrenic angle, as seen on lateral radiograph. The conspicuousness of the left cardiac border, as seen on PA chest radiograph, correlated with the presence of left extrapericardial fat, as seen on CT, and was related to the amount of left extrapericardial fat. Increased density of the anterior cardiophrenic angle, as seen on lateral radiographs, correlated with the presence of left extrapericardial fat on CT, but the absence of increased density on lateral radiograph corresponds to the absence or a minimal amount of left extrapericardial fat, as seen on CT. (author). 8 refs., 4 tabs., 3 figs

Pulmonary manifestations in HIV patients: The role of chest films, CT and HRCT

International Nuclear Information System (INIS)

Kauczor, H.U.; Schnuetgen, M.; Fischer, B.; Schwickert, H.C.; Haertel, S.; Schadmand-Fischer, S.; Gerken, G.; Schweden, F.

1995-01-01

64 HIV patients were examined prospectively. 15 had no respiratory symptoms (group I), 30 had non-specific respiratory symptoms (group II), 19 complained of dyspnoea (group III). Chest radiographs and CT were performed within a week. In patients with positive findings, bronchoscopy was carried out with bacteriological and histological examinations. In group I, 13% of chest radiographs and 40% of CT's showed infiltrative changes. In group II, the figures were 27% and 57% respectively. In group III, abnormalities were found in all cases by both examinations. (orig./MG) [de

Lung nodule detection on chest CT: evaluation of a computer-aided detection (CAD) system

International Nuclear Information System (INIS)

Lee, In Jae; Gamsu, Gordon; Czum, Julianna; Johnson, Rebecca; Chakrapani, Sanjay; Wu, Ning

2005-01-01

To evaluate the capacity of a computer-aided detection (CAD) system to detect lung nodules in clinical chest CT. A total of 210 consecutive clinical chest CT scans and their reports were reviewed by two chest radiologists and 70 were selected (33 without nodules and 37 with 1-6 nodules, 4-15.4 mm in diameter). The CAD system (ImageChecker CT LN-1000) developed by R2 Technology, Inc. (Sunnyvale, CA) was used. Its algorithm was designed to detect nodules with a diameter of 4-20 mm. The two chest radiologists working with the CAD system detected a total of 78 nodules. These 78 nodules form the database for this study. Four independent observers interpreted the studies with and without the CAD system. The detection rates of the four independent observers without CAD were 81% (63/78), 85% (66/78), 83% (65/78), and 83% (65/78), respectively. With CAD their rates were 87% (68/78), 85% (66/78), 86% (67/78), and 85% (66/78), respectively. The differences between these two sets of detection rates did not reach statistical significance. In addition, CAD detected eight nodules that were not mentioned in the original clinical radiology reports. The CAD system produced 1.56 false-positive nodules per CT study. The four test observers had 0, 0.1, 0.17, and 0.26 false-positive results per study without CAD and 0.07, 0.2, 0.23, and 0.39 with CAD, respectively. The CAD system can assist radiologists in detecting pulmonary nodules in chest CT, but with a potential increase in their false positive rates. Technological improvements to the system could increase the sensitivity and specificity for the detection of pulmonary nodules and reduce these false-positive results

Chest CT scans are frequently abnormal in asymptomatic patients with newly diagnosed acute myeloid leukemia.

Science.gov (United States)

Vallipuram, Janaki; Dhalla, Sidika; Bell, Chaim M; Dresser, Linda; Han, Heekyung; Husain, Shahid; Minden, Mark D; Paul, Narinder S; So, Miranda; Steinberg, Marilyn; Vallipuram, Mayuran; Wong, Gary; Morris, Andrew M

2017-04-01

Chest computed tomography (CT) findings of nodules, ground glass opacities, and consolidations are often interpreted as representing invasive fungal infection in individuals with febrile neutropenia. We assessed whether these CT findings were present in asymptomatic individuals with acute myeloid leukemia (AML) at low risk of invasive fungal disease. A retrospective study of consecutive asymptomatic adult patients with newly diagnosed AML over a 2-year period was performed at a tertiary care oncology center. Radiology reports of baseline chest CTs were reviewed. Of 145 CT scans, the majority (88%) had pulmonary abnormalities. Many (70%) had one or both of unspecified opacities (52%) and nodules (49%). Ground glass opacities (18%) and consolidations (12%) occurred less frequently. Radiologists suggested pneumonia as a possible diagnosis in 32% (n = 47) of scans. Chest CT may result in over-diagnosis of invasive fungal disease in individuals with febrile neutropenia if interpreted without correlation to the patients' clinical status.

Ultra-high pitch chest computed tomography at 70 kVp tube voltage in an anthropomorphic pediatric phantom and non-sedated pediatric patients: Initial experience with 3rd generation dual-source CT.

Science.gov (United States)

Hagelstein, Claudia; Henzler, Thomas; Haubenreisser, Holger; Meyer, Mathias; Sudarski, Sonja; Schoenberg, Stefan O; Neff, K Wolfgang; Weis, Meike

2016-12-01

Minimizing radiation dose while at the same time preserving image quality is of particular importance in pediatric chest CT. Very recently, CT imaging with a tube voltage of 70 kVp has become clinically available. However, image noise is inversely proportional to the tube voltage. We aimed to investigate radiation dose and image quality of pediatric chest CT performed at 70 kVp in an anthropomorphic pediatric phantom as well as in clinical patients. An anthropomorphic pediatric phantom, which resembles a one-year-old child in physiognomy, was scanned on the 3 rd generation dual-source CT (DSCT) system at 70 kVp and 80 kVp and a fixed ultra low tube-current of 8 mAs to solely evaluate the impact of lowering tube voltage. After the phantom measurements, 18 pediatric patients (mean 29.5 months; range 1-91 months; 21 examinations) underwent 3.2 high-pitch chest CT on the same DSCT system at 70 kVp tube voltage without any sedation. Radiation dose and presence of motion artifacts was compared to a retrospectively identified patient cohort examined at 80 kVp on a 16-slice single-source-CT (SSCT; n=15; 14/15 with sedation; mean 30.7 months; range 0-96 months; pitch=1.5) or on a 2 nd generation DSCT without any sedation (n=6; mean 32.8 months; range 4-61 months; pitch=3.2). Radiation dose in the phantom scans was reduced by approximately 40% when using a tube voltage of 70 kVp instead of 80 kVp. In the pediatric patient group examined at 70 kVp age-specific effective dose (ED; mean 0.5±0.2 mSv) was significantly lower when compared to the retrospective cohort scanned at 80 kVp on the 16-slice-SSCT (mean ED: 1.0±0.3 mSv; pCT examinations showed any motion artifacts whereas 13/15 examinations of the retrospective patient cohort scanned at 80 kVp with a pitch of 1.5 showed motion artifacts. 3.2 high-pitch chest CT performed with 70 kVp significantly reduces radiation dose when compared to 80 kVp while at the same time provides good image quality without any motion artifacts

Is energy imparted a good measure of the radiation risk associated with CT examinations

International Nuclear Information System (INIS)

Huda, W.

1984-01-01

The dose distribution in a Rando phantom has been measured for typical EMI 5005 CT scans of the head, chest, abdomen and pelvis. These dose distributions have been used to generate quantitative estimates of the somatic and genetic radiation risks associated with these CT examinations and also to measure the total energy imparted during each scan. A comparison has been made between the radiation risk estimates and the energy imparted measurements. The energy imparted measurements are not a good indicator of the somatic and/or genetic risks when one type of CT scan is compared with another. However, for a given type of scan, the energy imparted may be a reasonable indicator of the relative somatic risks associated with different CT examinations. Considerable care should be taken when interpreting and using any measured value of energy imparted in a radiological examination since published values of the risk per unit energy imparted can significantly underestimate the radiation risk. (author)

Air trapping on chest CT is associated with worse ventilation distribution in infants with cystic fibrosis diagnosed following newborn screening.

Directory of Open Access Journals (Sweden)

Graham L Hall

Full Text Available BACKGROUND: In school-aged children with cystic fibrosis (CF structural lung damage assessed using chest CT is associated with abnormal ventilation distribution. The primary objective of this analysis was to determine the relationships between ventilation distribution outcomes and the presence and extent of structural damage as assessed by chest CT in infants and young children with CF. METHODS: Data of infants and young children with CF diagnosed following newborn screening consecutively reviewed between August 2005 and December 2009 were analysed. Ventilation distribution (lung clearance index and the first and second moment ratios [LCI, M(1/M(0 and M(2/M(0, respectively], chest CT and airway pathology from bronchoalveolar lavage were determined at diagnosis and then annually. The chest CT scans were evaluated for the presence or absence of bronchiectasis and air trapping. RESULTS: Matched lung function, chest CT and pathology outcomes were available in 49 infants (31 male with bronchiectasis and air trapping present in 13 (27% and 24 (49% infants, respectively. The presence of bronchiectasis or air trapping was associated with increased M(2/M(0 but not LCI or M(1/M(0. There was a weak, but statistically significant association between the extent of air trapping and all ventilation distribution outcomes. CONCLUSION: These findings suggest that in early CF lung disease there are weak associations between ventilation distribution and lung damage from chest CT. These finding are in contrast to those reported in older children. These findings suggest that assessments of LCI could not be used to replace a chest CT scan for the assessment of structural lung disease in the first two years of life. Further research in which both MBW and chest CT outcomes are obtained is required to assess the role of ventilation distribution in tracking the progression of lung damage in infants with CF.

Predictors of abnormal chest CT after blunt trauma: a critical appraisal of the literature.

NARCIS (Netherlands)

Brink, M.; Kool, D.R.; Dekker, H.M.; Deunk, J.; Jager, G.J.; Kuijk, C. van; Edwards, M.J.R.; Blickman, J.G.

2009-01-01

AIM: To identify and to evaluate predictors that determine whether chest computed tomography (CT) is likely to reveal relevant injuries in adult blunt trauma patients. METHODS: After a comprehensive literature search for original studies on blunt chest injury diagnosis, two independent observers

Chest Fat Quantification via CT Based on Standardized Anatomy Space in Adult Lung Transplant Candidates.

Directory of Open Access Journals (Sweden)

Yubing Tong

Full Text Available Overweight and underweight conditions are considered relative contraindications to lung transplantation due to their association with excess mortality. Yet, recent work suggests that body mass index (BMI does not accurately reflect adipose tissue mass in adults with advanced lung diseases. Alternative and more accurate measures of adiposity are needed. Chest fat estimation by routine computed tomography (CT imaging may therefore be important for identifying high-risk lung transplant candidates. In this paper, an approach to chest fat quantification and quality assessment based on a recently formulated concept of standardized anatomic space (SAS is presented. The goal of the paper is to seek answers to several key questions related to chest fat quantity and quality assessment based on a single slice CT (whether in the chest, abdomen, or thigh versus a volumetric CT, which have not been addressed in the literature.Unenhanced chest CT image data sets from 40 adult lung transplant candidates (age 58 ± 12 yrs and BMI 26.4 ± 4.3 kg/m2, 16 with chronic obstructive pulmonary disease (COPD, 16 with idiopathic pulmonary fibrosis (IPF, and the remainder with other conditions were analyzed together with a single slice acquired for each patient at the L5 vertebral level and mid-thigh level. The thoracic body region and the interface between subcutaneous adipose tissue (SAT and visceral adipose tissue (VAT in the chest were consistently defined in all patients and delineated using Live Wire tools. The SAT and VAT components of chest were then segmented guided by this interface. The SAS approach was used to identify the corresponding anatomic slices in each chest CT study, and SAT and VAT areas in each slice as well as their whole volumes were quantified. Similarly, the SAT and VAT components were segmented in the abdomen and thigh slices. Key parameters of the attenuation (Hounsfield unit (HU distributions were determined from each chest slice and from the

Chest computed tomography

DEFF Research Database (Denmark)

Loeve, Martine; Krestin, Gabriel P.; Rosenfeld, Margaret

2013-01-01

are not suitable to study CF lung disease in young children. Chest computed tomography (CT) holds great promise for use as a sensitive surrogate endpoint in CF. A large body of evidence has been produced to validate the use of chest CT as primary endpoint to study CF lung disease. However, before chest CT can...

Hematogenous candida pneumonia in major burn patients: plain chest radiograph and thin-section CT findings

International Nuclear Information System (INIS)

Kim, Hyo Heon; Lee, Eil Seong; Shim, Ya Seong; Kim, Ji Hun; Suh, Hong Kil; Cho, Sin Young; Kim, Dae Sun; Lee, Kil Woo; Kang, Ik Won

1995-01-01

To describe plain radiographic and thin-section CT findings of hematogenous candida pneumonia in major burn patients. We reviewed nine cases of hematogenous candida pneumonia in major burn patients who had positive blood culture for candida and findings of pneumonia on plain chest radiograph. On five of nine cases, thin-section CT was done. We evaluated retrospectively nine cases for onset, the pattern, distribution, and size of lesions on plain chest radiograph and thin-section CT. On plain chest radiograph, randomly distributed 2-10 mm nodules were seen in six cases(66%) and randomly distributed 10-15 mm consolidations in remaining three cases(33%). Lesion occurred in 11th to 75th post-burn day(average, 34th post-burn day). Other findings were cardiomegaly in three cases, atelectasis in three cases, and pulmonary edema in one case. Thin-section CT showed variable shaped subpleural nodules in all five cases. The size of nodules were 1-5 mm in two cases(40%) and 5-10 mm(60%) in three cases. Feeding vessel signs were seen in two cases. Other findings were atelectasis in three cases, cardiomegaly in three cases, ground-glass opacity and interlobular septal thickenings by pulmonary edema in two cases. Plain chest radiographic findings of hematogenous candida pneumonia in major burn patients are randomly distributed nodules or consolidations of variable size. Thin-section CT findings are variable shaped subpleural nodules less than 1 cm

Dose reduction with adaptive statistical iterative reconstruction for paediatric CT: phantom study and clinical experience on chest and abdomen CT

Energy Technology Data Exchange (ETDEWEB)

Gay, F.; Lasalle, S.; Neuenschwander, S.; Brisse, H.J. [Institut Curie, Imaging Department, Paris (France); Pavia, Y.; Pierrat, N. [Institut Curie, Medical Physics Department, Paris (France)

2014-01-15

To assess the benefit and limits of iterative reconstruction of paediatric chest and abdominal computed tomography (CT). The study compared adaptive statistical iterative reconstruction (ASIR) with filtered back projection (FBP) on 64-channel MDCT. A phantom study was first performed using variable tube potential, tube current and ASIR settings. The assessed image quality indices were the signal-to-noise ratio (SNR), the noise power spectrum, low contrast detectability (LCD) and spatial resolution. A clinical retrospective study of 26 children (M:F = 14/12, mean age: 4 years, range: 1-9 years) was secondarily performed allowing comparison of 18 chest and 14 abdominal CT pairs, one with a routine CT dose and FBP reconstruction, and the other with 30 % lower dose and 40 % ASIR reconstruction. Two radiologists independently compared the images for overall image quality, noise, sharpness and artefacts, and measured image noise. The phantom study demonstrated a significant increase in SNR without impairment of the LCD or spatial resolution, except for tube current values below 30-50 mA. On clinical images, no significant difference was observed between FBP and reduced dose ASIR images. Iterative reconstruction allows at least 30 % dose reduction in paediatric chest and abdominal CT, without impairment of image quality. (orig.)

Dose reduction with adaptive statistical iterative reconstruction for paediatric CT: phantom study and clinical experience on chest and abdomen CT

International Nuclear Information System (INIS)

Gay, F.; Lasalle, S.; Neuenschwander, S.; Brisse, H.J.; Pavia, Y.; Pierrat, N.

2014-01-01

To assess the benefit and limits of iterative reconstruction of paediatric chest and abdominal computed tomography (CT). The study compared adaptive statistical iterative reconstruction (ASIR) with filtered back projection (FBP) on 64-channel MDCT. A phantom study was first performed using variable tube potential, tube current and ASIR settings. The assessed image quality indices were the signal-to-noise ratio (SNR), the noise power spectrum, low contrast detectability (LCD) and spatial resolution. A clinical retrospective study of 26 children (M:F = 14/12, mean age: 4 years, range: 1-9 years) was secondarily performed allowing comparison of 18 chest and 14 abdominal CT pairs, one with a routine CT dose and FBP reconstruction, and the other with 30 % lower dose and 40 % ASIR reconstruction. Two radiologists independently compared the images for overall image quality, noise, sharpness and artefacts, and measured image noise. The phantom study demonstrated a significant increase in SNR without impairment of the LCD or spatial resolution, except for tube current values below 30-50 mA. On clinical images, no significant difference was observed between FBP and reduced dose ASIR images. Iterative reconstruction allows at least 30 % dose reduction in paediatric chest and abdominal CT, without impairment of image quality. (orig.)

A method for smoothing segmented lung boundary in chest CT images

Science.gov (United States)

Yim, Yeny; Hong, Helen

2007-03-01

To segment low density lung regions in chest CT images, most of methods use the difference in gray-level value of pixels. However, radiodense pulmonary vessels and pleural nodules that contact with the surrounding anatomy are often excluded from the segmentation result. To smooth lung boundary segmented by gray-level processing in chest CT images, we propose a new method using scan line search. Our method consists of three main steps. First, lung boundary is extracted by our automatic segmentation method. Second, segmented lung contour is smoothed in each axial CT slice. We propose a scan line search to track the points on lung contour and find rapidly changing curvature efficiently. Finally, to provide consistent appearance between lung contours in adjacent axial slices, 2D closing in coronal plane is applied within pre-defined subvolume. Our method has been applied for performance evaluation with the aspects of visual inspection, accuracy and processing time. The results of our method show that the smoothness of lung contour was considerably increased by compensating for pulmonary vessels and pleural nodules.

Ultra low-dose chest CT using filtered back projection: Comparison of 80-, 100- and 120 kVp protocols in a prospective randomized study

Energy Technology Data Exchange (ETDEWEB)

Khawaja, Ranish Deedar Ali, E-mail: rkhawaja@mgh.harvard.edu [Division of Thoracic Radiology, MGH Imaging, Massachusetts General Hospital and Harvard Medical School, Boston (United States); Singh, Sarabjeet [Division of Thoracic Radiology, MGH Imaging, Massachusetts General Hospital and Harvard Medical School, Boston (United States); Madan, Rachna [Division of Thoracic Radiology, Brigham and Women' s Hospital and Harvard Medical School, Boston (United States); Sharma, Amita; Padole, Atul; Pourjabbar, Sarvenaz; Digumarthy, Subba; Shepard, Jo-Anne; Kalra, Mannudeep K. [Division of Thoracic Radiology, MGH Imaging, Massachusetts General Hospital and Harvard Medical School, Boston (United States)

2014-10-15

Highlights: • Filtered back projection technique enables acceptable image quality for chest CT examinations at 0.9 mGy (estimated effective dose of 0.5 mSv) for selected sizes of patients. • Lesion detection (such as solid non-calcified lung nodules) in lung parenchyma is optimal at 0.9 mGy, with limited visualization of thyroid nodules in FBP images. • Further dose reduction down to 0.4 mGy is possible for most patients undergoing follow-up chest CT for evaluation of larger lung nodules and GGOs. • Our results may help set the reference ALARA dose for chest CT examinations reconstructed with filtered back projection technique using the minimum possible radiation dose with acceptable image quality and lesion detection. - Abstract: Purpose: To assess lesion detection and diagnostic image quality of filtered back projection (FBP) reconstruction technique in ultra low-dose chest CT examinations. Methods and materials: In this IRB-approved ongoing prospective clinical study, 116 CT-image-series at four different radiation-doses were performed for 29 patients (age, 57–87 years; F:M – 15:12; BMI 16–32 kg/m{sup 2}). All patients provided written-informed-consent for the acquisitions of additional ultra low-dose (ULD) series on a 256-slice MDCT (iCT, Philips Healthcare). In-addition to their clinical standard-dose chest CT (SD, 120 kV mean CTDI{sub vol}, 6 ± 1 mGy), ULD-CT was subsequently performed at three-dose-levels (0.9 mGy [120 kV]; 0.5 mGy [100 kV] and 0.2 mGy [80 kV]). Images were reconstructed with FBP (2.5 mm * 1.25 mm) resulting into four-stacks: SD-FBP (reference-standard), FBP{sub 0.9}, FBP{sub 0.5}, and FBP{sub 0.2}. Four thoracic-radiologists from two-teaching-hospitals independently-evaluated data for lesion-detection and visibility-of-small-structures. Friedman's-non-parametric-test with post hoc Dunn's-test was used for data-analysis. Results: Interobserver-agreement was substantial between radiologists (k = 0.6–0.8). With

An Evaluation of pectus excavatum by means of body surface measurements on chest CT scans

International Nuclear Information System (INIS)

Hirotani, Taichi; Ohama, Kazunori; Shimotake, Takashi; Ishikawa, Nobuki; Watanabe, Reiji

2009-01-01

The aim of this study is to determine whether the body surface index replaces the Haller index in order to evaluate the severity of pectus excavatum. Sixty-nine cases with a diagnosis of pectus excavatum between August 2001 and January 2008 were prospectively enrolled in the study. The anterior-posterior chest dimension, lateral chest dimension and depth of the most profound depressed area were measured. The body surface index was expressed as an equation A/(B-C), where A was the transverse diameter, B was the anterior-posterior diameter and C was the depth of the depressed area. This index was compared to the Haller index in each patient. In this study, each value was measured on a chest CT scan. The body surface index significantly correlated with the Haller index, in which the coefficient of correlation was 0.879 (p<0.01). The body surface index corresponding to Haller index 3.25 seems to be 1.67. We could find the body surface index corresponding to each Haller index. We propose that an evaluation of pectus excavatum by means of body surface measurements is clinically useful, and may replace the Haller index. The body surface index may allow us to assess the severity of pectus excavatum without a CT scan, resulting in a reduction of radiation exposure for children with pectus excavatum. It's possible to evaluate the body surface index by using a relational table between this index and the Hailer index. We'll evaluate the body surface index by using values measured on a real body. (author)

Laryngotracheobronchial papillomatosis: chest CT findings

Energy Technology Data Exchange (ETDEWEB)

Fortes, Helena Ribeiro; Zanetti, Glaucia; Marchiori, Edson, E-mail: edmarchiori@gmail.com [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Ranke, Felipe Mussi von [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Escuissato, Dante Luiz [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Clinica Medica; Araujo Neto, Cesar Augusto [Universidade Federal da Bahia (UFBA), Salvador (Brazil). Dept. de Medicina e Apoio Diagnostico; Hochhegger, Bruno [Universidade Federal de Ciencias da Saude de Porto Alegre (UFCSPA), RS (Brazil). Diagnostico por Imagem; Irion, Klaus Loureiro [Liverpool Heart and Chest Hospital NHS Foundation Trust, Liverpool (United Kingdom); Souza, Carolina Althoff [Dept. of Diagnostic Imaging, The Ottawa Hospital, University of Ottawa, Ontario (Canada)

2017-07-15

To evaluate the findings on chest CTs in 16 patients (8 men and 8 women) with laryngotracheobronchial papillomatosis. Methods: This was a retrospective study involving patients ranging from 2 to 72 years of age. The evaluation of the CT scans was independently performed by two observers, and discordant results were resolved by consensus. The inclusion criteria were presence of abnormalities on the CT scans, and the diagnosis was confirmed by anatomopathological examination of the papillomatous lesions. Results: The most common symptoms were hoarseness, cough, dyspnea, and recurrent respiratory infections. The major CT findings were nodular formations in the trachea, solid or cavitated nodules in the lung parenchyma, air trapping, masses, and consolidation. Nodular formations in the trachea were observed in 14 patients (87.5%). Only 2 patients had lesions in lung parenchyma without tracheal involvement. Only 1 patient had no pulmonary dissemination of the disease, showing airway involvement only. Solid and cavitated lung nodules were observed in 14 patients (87.5%) and 13 (81.2%), respectively. Masses were observed in 6 patients (37.5%); air trapping, in 3 (18.7%); consolidation in 3 (18.7%); and pleural effusion, in 1 (6.3%). Pulmonary involvement was bilateral in all cases. Conclusions: The most common tomography findings were nodular formations in the trachea, as well as solid or cavitated nodules and masses in the lung parenchyma. Malignant transformation of the lesions was observed in 5 cases. (author)

Interstitial shadow on chest CT is associated with the onset of interstitial lung disease caused by chemotherapeutic drugs

International Nuclear Information System (INIS)

Niho, Seiji; Goto, Koichi; Yoh, Kiyotaka; Kim, Y.H.; Ohmatsu, Hironobu; Kubota, Kaoru; Saijo, Nagahiro; Nishiwaki, Yutaka

2006-01-01

Pretreatment computerized tomography (CT) films of the chest was studied to clarify the influence of interstitial shadow on developing interstitial lung disease (ILD). Eligible patients were those lung cancer patients who started to receive first-line chemotherapy between October 2001 and March 2004. Patients who received thoracic radiotherapy to the primary lesion, mediastinum, spinal or rib metastases were excluded. We reviewed pretreatment conventional CT and plain X-ray films of the chest. Ground-glass opacity, consolidation or reticular shadow without segmental distribution was defined as interstitial shadow, with this event being graded as mild, moderate or severe. If interstitial shadow was detected on CT films of the chest, but not via plain chest X-ray, it was graded as mild. Patients developing ILD were identified from medial records. A total of 502 patients were eligible. Mild, moderate and severe interstitial shadow was identified in 7, 8 and 5% of patients, respectively. A total of 188 patients (37%) received tyrosine kinase inhibitor (TKI) treatment, namely gefitinib or erlotinib. Twenty-six patients (5.2%) developed ILD either during or after chemotherapy. Multivariate analyses revealed that interstitial shadow on CT films of the chest and treatment history with TKI were associated with the onset of ILD. It is recommended that patients with interstitial shadow on chest CT are excluded from future clinical trials until this issue is further clarified, as it is anticipated that use of chemotherapeutic agents frequently mediate onset of ILD in this context. (author)

Assessment of chest pain in the emergency room: What is the role of multidetector CT?

International Nuclear Information System (INIS)

White, Charles; Read, Katrina; Kuo, Dick

2006-01-01

Chest pain is one of the most frequent complaints for patients seen in the emergency department. The current article describes the clinical stratification of patients who present to the emergency department with chest pain and discusses imaging options and analysis for these patients. It reviews conventional imaging approaches to assessing chest pain including chest radiography and stress testing. The main discussion focuses on the potential utility use of cross-sectional imaging, particularly multidetector CT, in the evaluation of chest pain in the emergency department

Combining automatic tube current modulation with adaptive statistical iterative reconstruction for low-dose chest CT screening.

Directory of Open Access Journals (Sweden)

Jiang-Hong Chen

Full Text Available To reduce radiation dose while maintaining image quality in low-dose chest computed tomography (CT by combining adaptive statistical iterative reconstruction (ASIR and automatic tube current modulation (ATCM.Patients undergoing cancer screening (n = 200 were subjected to 64-slice multidetector chest CT scanning with ASIR and ATCM. Patients were divided into groups 1, 2, 3, and 4 (n = 50 each, with a noise index (NI of 15, 20, 30, and 40, respectively. Each image set was reconstructed with 4 ASIR levels (0% ASIR, 30% ASIR, 50% ASIR, and 80% ASIR in each group. Two radiologists assessed subjective image noise, image artifacts, and visibility of the anatomical structures. Objective image noise and signal-to-noise ratio (SNR were measured, and effective dose (ED was recorded.Increased NI was associated with increased subjective and objective image noise results (P<0.001, and SNR decreased with increasing NI (P<0.001. These values improved with increased ASIR levels (P<0.001. Images from all 4 groups were clinically diagnosable. Images with NI = 30 and 50% ASIR had average subjective image noise scores and nearly average anatomical structure visibility scores, with a mean objective image noise of 23.42 HU. The EDs for groups 1, 2, 3 and 4 were 2.79 ± 1.17, 1.69 ± 0.59, 0.74 ± 0.29, and 0.37 ± 0.22 mSv, respectively. Compared to group 1 (NI = 15, the ED reductions were 39.43%, 73.48%, and 86.74% for groups 2, 3, and 4, respectively.Using NI = 30 with 50% ASIR in the chest CT protocol, we obtained average or above-average image quality but a reduced ED.

Chest Tomosynthesis: Technical Principles and Clinical Update

Science.gov (United States)

Dobbins, James T.; McAdams, H. Page

2009-01-01

Digital tomosynthesis is a radiographic technique that can produce an arbitrary number of section images of a patient from a single pass of the x-ray tube. It utilizes a conventional x-ray tube, a flat-panel detector, a computer-controlled tube mover, and special reconstruction algorithms to produce section images. While it does not have the depth resolution of computed tomography (CT), tomosynthesis provides some of the tomographic benefits of CT but at lower cost and radiation dose than CT. Compared to conventional chest radiography, chest tomosynthesis results in improved visibility of normal structures such as vessels, airway and spine. By reducing visual clutter from overlying normal anatomy, it also enhances detection of small lung nodules. This review article outlines the components of a tomosynthesis system, discusses results regarding improved lung nodule detection from the recent literature, and presents examples of nodule detection from a clinical trial in human subjects. Possible implementation strategies for use in clinical chest imaging are discussed. PMID:19616909

Determination of the optimal dose reduction level via iterative reconstruction using 640-slice volume chest CT in a pig model.

Directory of Open Access Journals (Sweden)

Xingli Liu

Full Text Available To determine the optimal dose reduction level of iterative reconstruction technique for paediatric chest CT in pig models.27 infant pigs underwent 640-slice volume chest CT with 80kVp and different mAs. Automatic exposure control technique was used, and the index of noise was set to SD10 (Group A, routine dose, SD12.5, SD15, SD17.5, SD20 (Groups from B to E to reduce dose respectively. Group A was reconstructed with filtered back projection (FBP, and Groups from B to E were reconstructed using iterative reconstruction (IR. Objective and subjective image quality (IQ among groups were compared to determine an optimal radiation reduction level.The noise and signal-to-noise ratio (SNR in Group D had no significant statistical difference from that in Group A (P = 1.0. The scores of subjective IQ in Group A were not significantly different from those in Group D (P>0.05. There were no obvious statistical differences in the objective and subjective index values among the subgroups (small, medium and large subgroups of Group D. The effective dose (ED of Group D was 58.9% lower than that of Group A (0.20±0.05mSv vs 0.48±0.10mSv, p <0.001.In infant pig chest CT, using iterative reconstruction can provide diagnostic image quality; furthermore, it can reduce the dosage by 58.9%.

Chest tomosynthesis: technical and clinical perspectives.

Science.gov (United States)

Johnsson, Ase Allansdotter; Vikgren, Jenny; Bath, Magnus

2014-02-01

The recent implementation of chest tomosynthesis is built on the availability of large, dose-efficient, high-resolution flat panel detectors, which enable the acquisition of the necessary number of projection radiographs to allow reconstruction of section images of the chest within one breath hold. A chest tomosynthesis examination obtains the increased diagnostic information provided by volumetric imaging at a radiation dose comparable to that of conventional chest radiography. There is evidence that the sensitivity of chest tomosynthesis may be at least three times higher than for conventional chest radiography for detection of pulmonary nodules. The sensitivity increases with increasing nodule size and attenuation and decreases for nodules with subpleural location. Differentiation between pleural and subpleural lesions is a known pitfall due to the limited depth resolution in chest tomosynthesis. Studies on different types of pathology report increased detectability in favor of chest tomosynthesis in comparison to chest radiography. The technique provides improved diagnostic accuracy and confidence in the diagnosis of suspected pulmonary lesions on chest radiography and facilitates the exclusion of pulmonary lesions in a majority of patients, avoiding the need for computed tomography (CT). However, motion artifacts can be a cumbersome limitation and breathing during the tomosynthesis image acquisition may result in severe artifacts significantly affecting the detectability of pathology. In summary, chest tomosynthesis has been shown to be superior to chest conventional radiography for many tasks and to be able to replace CT in selected cases. In our experience chest tomosynthesis is an efficient problem solver in daily clinical work. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Ultra-high pitch chest computed tomography at 70 kVp tube voltage in an anthropomorphic pediatric phantom and non-sedated pediatric patients. Initial experience with 3{sup rd} generation dual-source CT

Energy Technology Data Exchange (ETDEWEB)

Hagelstein, Claudia; Henzler, Thomas; Haubenreisser, Holger; Meyer, Mathias; Sudarski, Sonja; Schoenberg, Stefan O.; Neff, K. Wolfgang; Weis, Meike [Univ. Medical Center Mannheim (Germany). Inst. of Clinical Radiology and Nuclear Medicine

2016-07-01

Minimizing radiation dose while at the same time preserving image quality is of particular importance in pediatric chest CT. Very recently, CT imaging with a tube voltage of 70 kVp has become clinically available. However, image noise is inversely proportional to the tube voltage. We aimed to investigate radiation dose and image quality of pediatric chest CT performed at 70 kVp in an anthropomorphic pediatric phantom as well as in clinical patients. An anthropomorphic pediatric phantom, which resembles a one-year-old child in physiognomy, was scanned on the 3{sup rd} generation dual-source CT (DSCT) system at 70 kVp and 80 kVp and a fixed ultra low tube-current of 8 mAs to solely evaluate the impact of lowering tube voltage. After the phantom measurements, 18 pediatric patients (mean 29.5 months; range 1-91 months; 21 examinations) underwent 3.2 high-pitch chest CT on the same DSCT system at 70 kVp tube voltage without any sedation. Radiation dose and presence of motion artifacts was compared to a retrospectively identified patient cohort examined at 80 kVp on a 16-slice single-source-CT (SSCT; n = 15; 14/15 with sedation; mean 30.7 months; range 0-96 months; pitch = 1.5) or on a 2{sup nd} generation DSCT without any sedation (n = 6; mean 32.8 months; range 4-61 months; pitch = 3.2). Radiation dose in the phantom scans was reduced by approximately 40% when using a tube voltage of 70 kVp instead of 80 kVp. In the pediatric patient group examined at 70 kVp age-specific effective dose (ED; mean 0.5 ± 0.2 mSv) was significantly lower when compared to the retrospective cohort scanned at 80 kVp on the 16-slice-SSCT (mean ED: 1.0 ± 0.3 mSv; p < 0.0001) and also considerably lower when compared to the cohort scanned at 80 kVp on the 2{sup nd} generation DSCT (mean ED: 0.9 ± 0.5 mSv). None of the prospective, sedation-free CT examinations showed any motion artifacts whereas 13/15 examinations of the retrospective patient cohort scanned at 80 kVp with a pitch of 1

The oblique interface in the right cardiophrenic angle: chest radiographic-CT correlation

International Nuclear Information System (INIS)

Kim, Jeung Sook; Lee, Kyung Soo; Choo, Sung Wook; Choo, In Wook

1996-01-01

An oblique interface in the right cardiophrenic angle, extending superomedially from right retrocardiac or supradiaphragmatic region inferolaterally to peridiaphragmatic region, is occasionally observed on posteroanterior chest radiograph. The aim of this study was to evaluate the frequency of visualization of the interface on chest radiographs and to elucidate its nature on radiographic-CT correlation. Posteroanterior chest radiographs from 300 consecutive subjects were analyzed to evaluate the frequency and demographic data about an oblique interface in the right cardiophrenic angle. Thin-section CT scans(1-mm collimation and 5-mm intervals) were obtained from the subjects with positive interface on chest radiograph for assessment of the nature of the interface. The demographic data in the subjects with and without the interface were tested statistically to note any difference between two groups. Oblique interface in the right cardiophrenic angle was present in 29 subjects(9.7%) on chest radiograph. The age of the subjects with positive interface(13 men and 16 women) ranged from 19 to 70 years(mean±SD, 47±12.7 years) whereas the age of the subjects without the interface from 16 to 82 years (mean±SD, 50±9.1 years)(p>0.1). The body weight of the subjects with the interface ranged from 41 to 72 Kg(mean±SD, 60±8.0Kg) whereas the body weight of the subjects without the interface from 41 to 85Kg(mean±SD, 63±10.1Kg)(p>0.1). On CT scan, it was formed due to contact between the epipericardial fat and the right middle lobe of the lung in 27 subjects(93%) and between the inferior vena cava and the medial basal segment of the right lower lobe of the lung in two(7%). Oblique interface in the right cardiophrenic angle is occasionally visualized on chest radiograph. It is formed due to contact between the right middle lobe of the lung and pericardial fat in most cases. The frequency of visualization of the interface has no relationship to age and body weight of the

The “dirty chest”—correlations between chest radiography, multislice CT and tobacco burden

Science.gov (United States)

Kirchner, J; Goltz, J P; Lorenz, F; Obermann, A; Kirchner, E M; Kickuth, R

2012-01-01

Objectives Cigarette smoking-induced airway disease commonly results in an overall increase of non-specific lung markings on chest radiography. This has been described as “dirty chest”. As the morphological substrate of this condition is similar to the anthracosilicosis of coal workers, we hypothesised that it is possible to quantify the radiological changes using the International Labour Organization (ILO) classification of pneumoconiosis. The aims of this study were to evaluate whether there is a correlation between the extent of cigarette smoking and increased lung markings on chest radiography and to correlate the chest radiographic scores with findings on CT studies. Methods In a prospective analysis a cohort of 85 smokers was examined. The cigarette consumption was evaluated in pack years (defined as 20 cigarettes per day over 1 year). Film reading was performed by two board-certified radiologists. Chest radiographs were evaluated for the presence of thickening of bronchial walls, the presence of linear or nodular opacities, and emphysema. To correlate the smoking habits with the increase of overall lung markings in chest radiography, the ILO profusion score was converted to numbers ranging from zero to nine. Chest radiographs were rated according to the complete set of standard films of the revised ILO classification. Results 63/85 (74%) of the smokers showed an increase in overall lung markings on chest radiography; 32 (37%) had an ILO profusion score of chest radiography and the cigarette consumption quantified as pack years (r=0.68). The majority of the heavy smokers (>40 pack years) showed emphysema; there was no significant difference between the prevalence of emphysema as diagnosed by CT (62%) or chest radiography (71%) (pchest radiography. PMID:21937617

Early experiences with crowdsourcing airway annotations in chest CT

DEFF Research Database (Denmark)

Cheplygina, Veronika; Perez-Rovira, Adria; Kuo, Wieying

2016-01-01

Measuring airways in chest computed tomography (CT) images is important for characterizing diseases such as cystic fibrosis, yet very time-consuming to perform manually. Machine learning algorithms offer an alternative, but need large sets of annotated data to perform well. We investigate whether...... a number of further research directions and provide insight into the challenges of crowdsourcing in medical images from the perspective of first-time users....

Adaptive wiener filter based on Gaussian mixture distribution model for denoising chest X-ray CT image

International Nuclear Information System (INIS)

Tabuchi, Motohiro; Yamane, Nobumoto; Morikawa, Yoshitaka

2008-01-01

In recent decades, X-ray CT imaging has become more important as a result of its high-resolution performance. However, it is well known that the X-ray dose is insufficient in the techniques that use low-dose imaging in health screening or thin-slice imaging in work-up. Therefore, the degradation of CT images caused by the streak artifact frequently becomes problematic. In this study, we applied a Wiener filter (WF) using the universal Gaussian mixture distribution model (UNI-GMM) as a statistical model to remove streak artifact. In designing the WF, it is necessary to estimate the statistical model and the precise co-variances of the original image. In the proposed method, we obtained a variety of chest X-ray CT images using a phantom simulating a chest organ, and we estimated the statistical information using the images for training. The results of simulation showed that it is possible to fit the UNI-GMM to the chest X-ray CT images and reduce the specific noise. (author)

Nontuberculous Mycobacterial (NTM) Disease in Immunocompetent Patients: Expanding Image Findings on Chest CT

Energy Technology Data Exchange (ETDEWEB)

Shin, Hyo Hyun; Seon, Hyun Ju; Kim, Mok Hee; Choi, Song; Song, Sang Gook; Shin, Sang Soo; Kim, Yun Hyeon; Park, Jin Gyoon [Chonnam National University Hospital, Gwangju (Korea, Republic of)

2010-04-15

The aim of this study was to evaluate the chest CT features of nontuberculous mycobacterial (NTM) disease regardless of the specific organisms. This study included 74 consecutive patients (35 men, 39 women; mean age, 63 years; age range, 25-89 years) who were diagnosed with NTM disease according to the American Thoracic Society Guidelines (1997 and 2007) between January 2005 and July 2007. Chest CT images were randomly reviewed by two radiologists with consensus. The most common organism associated with NTM disease is M. avium-intracellulare complex (87.8%), followed by M. abscesses, M. kansasii, and M. chelonae. The most common chest CT finding was a nodular bronchiectatic lesion (n = 35, 46.7%), followed by a cavitary lesion of the upper lobe (n = 21, 28.0%), combined lesions of two prior subtypes (n = 6, 8.0%), consolidative lesion (s) (n = 5, 6.7%), a bronchogenic spreading pulmonary tuberculosis-like lesion (n = 5, 6.7%), a cavitary mass lesion with small satellite nodules (n = 2, 2.7%), and a miliary nodular lesion (n = 1, 1.3%). More than 5 segments were involved in 60 cases (81.1%). The nodular bronchiectatic lesion or cavitary lesion of upper lobe presents with multi-segmental involvement and the occurrence of combined consolidation is indicative of NTM disease

Low-tube-voltage selection for non-contrast-enhanced CT: Comparison of the radiation dose in pediatric and adult phantoms.

Science.gov (United States)

Shimonobo, Toshiaki; Funama, Yoshinori; Utsunomiya, Daisuke; Nakaura, Takeshi; Oda, Seitaro; Kiguchi, Masao; Masuda, Takanori; Sakabe, Daisuke; Yamashita, Yasuyuki; Awai, Kazuo

2016-01-01

We used pediatric and adult anthropomorphic phantoms to compare the radiation dose of low- and standard tube voltage chest and abdominal non-contrast-enhanced computed tomography (CT) scans. We also discuss the optimal low tube voltage for non-contrast-enhanced CT. Using a female adult- and three differently-sized pediatric anthropomorphic phantoms we acquired chest and abdominal non-contrast-enhanced scans on a 320-multidetector CT volume scanner. The tube voltage was set at 80-, 100-, and 120 kVp. The tube current was automatically assigned on the CT scanner in response to the set image noise level. On each phantom and at each tube voltage we measured the surface and center dose using high-sensitivity metal-oxide-semiconductor field-effect transistor detectors. The mean surface dose of chest and abdominal CT scans in 5-year olds was 4.4 and 5.3 mGy at 80 kVp, 4.5 and 5.4 mGy at 100 kV, and 4.0 and 5.0 mGy at 120 kVp, respectively. These values were similar in our 3-pediatric phantoms (p > 0.05). The mean surface dose in the adult phantom increased from 14.7 to 19.4 mGy for chest- and from 18.7 to 24.8 mGy for abdominal CT as the tube voltage decreased from 120 to 80 kVp (p voltage and the low tube voltage technique can be used for non-contrast-enhanced chest- and abdominal scanning. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

The utility of computed tomography as a screening tool for the evaluation of pediatric blunt chest trauma.

Science.gov (United States)

Markel, Troy A; Kumar, Rajiv; Koontz, Nicholas A; Scherer, L R; Applegate, Kimberly E

2009-07-01

There is a growing concern that computed tomography (CT) is being unnecessarily overused for the evaluation of pediatric patients. The purpose of this study was to analyze the trends and utility of chest CT use compared with chest X-ray (CXR) for the evaluation of children with blunt chest trauma. A 4-year retrospective review was performed for pediatric patients who underwent chest CT within 24 hours of sustaining blunt trauma at a Level-I trauma center. Trends in the use of CT and CXR were documented, and results of radiology reports were analyzed and compared with clinical outcomes. Three hundred thirty-three children, mean age 11 years, had chest CTs, increasing from 5.5% in 2001-2002 to 10.5% in 2004-2005 (p tool to analyze which patients may require CT evaluation. A multidisciplinary approach is warranted to develop guidelines that standardize the use of CT and thereby decreases unnecessary radiation exposure to pediatric patients.

Emphysema quantification and lung volumetry in chest X-ray equivalent ultralow dose CT - Intra-individual comparison with standard dose CT.

Science.gov (United States)

Messerli, Michael; Ottilinger, Thorsten; Warschkow, René; Leschka, Sebastian; Alkadhi, Hatem; Wildermuth, Simon; Bauer, Ralf W

2017-06-01

To determine whether ultralow dose chest CT with tin filtration can be used for emphysema quantification and lung volumetry and to assess differences in emphysema measurements and lung volume between standard dose and ultralow dose CT scans using advanced modeled iterative reconstruction (ADMIRE). 84 consecutive patients from a prospective, IRB-approved single-center study were included and underwent clinically indicated standard dose chest CT (1.7±0.6mSv) and additional single-energy ultralow dose CT (0.14±0.01mSv) at 100kV and fixed tube current at 70mAs with tin filtration in the same session. Forty of the 84 patients (48%) had no emphysema, 44 (52%) had emphysema. One radiologist performed fully automated software-based pulmonary emphysema quantification and lung volumetry of standard and ultralow dose CT with different levels of ADMIRE. Friedman test and Wilcoxon rank sum test were used for multiple comparison of emphysema and lung volume. Lung volumes were compared using the concordance correlation coefficient. The median low-attenuation areas (LAA) using filtered back projection (FBP) in standard dose was 4.4% and decreased to 2.6%, 2.1% and 1.8% using ADMIRE 3, 4, and 5, respectively. The median values of LAA in ultralow dose CT were 5.7%, 4.1% and 2.4% for ADMIRE 3, 4, and 5, respectively. There was no statistically significant difference between LAA in standard dose CT using FBP and ultralow dose using ADMIRE 4 (p=0.358) as well as in standard dose CT using ADMIRE 3 and ultralow dose using ADMIRE 5 (p=0.966). In comparison with standard dose FBP the concordance correlation coefficients of lung volumetry were 1.000, 0.999, and 0.999 for ADMIRE 3, 4, and 5 in standard dose, and 0.972 for ADMIRE 3, 4 and 5 in ultralow dose CT. Ultralow dose CT at chest X-ray equivalent dose levels allows for lung volumetry as well as detection and quantification of emphysema. However, longitudinal emphysema analyses should be performed with the same scan protocol and

Radiographic, CT and MRI spectrum of hydatid disease of the chest: a pictorial essay

Energy Technology Data Exchange (ETDEWEB)

Sinner, W.N. von [Dept. of Radiology MBC28, King Faisal Specialist Hospital and Research Centre, Riyadh (Saudi Arabia)

1993-01-01

Thirty patients with thoracic hydatidosis (Echinococcus granulosus) were studied. The hydatid cysts were located in the lung parenchyma (70%), mediastinum (6.7%), inside the heart (10%), the pleurae (10%) and the chest wall (3.3%). Complications of thoracic hydatid cysts, such as rupture, infection, pleural involvement, spread and calcifications are presented. Computed tomography (CT) without and/or with contrast enhancement was performed in all patients (30). Findings from conventional chest radiographs were compared with CT and confirmed by pathology (30). In 10 cases (33.3%), magnetic resonance imaging was also performed. The diagnostic spectrum of hydatid cysts, including variations and developmental stages, is presented in this pictorial essay. (orig.)

Radiation exposure distribution in patients undergoing CT brain scans

International Nuclear Information System (INIS)

Yang Zhanshan; Feng Dinghua; Chang Zichi; Li Shijun

1989-12-01

The distribution of surface exposures in patients undergoing single and multiple computerized tomographic brain scans with Hitachi CT-W500 was measured by LiF(Mg, Ti) thermoluminescent dosimetry. It was found that there was no significant difference in the sufrace exposures from different scanning slices. However, the exposure doses at different scanning angles around the head were different significantly. The reference point of the maximum surface exposure was at the temporal part of the head. the maximum surface exposure was at 1.65 x 10 -3 C·kg -1 while the average exposure was 1.55 x 10 -3 C·kg -1 . The ratio of the average dose resulting from nine scans to that from a single scan was 1.3, and the surface exposure contribution of scattered radiation was computed. At the same time the radiation doses to eyes, thyroid, chest and gonads of patiens at corresponding position were also measured and were compared with those from CT cranial scans in children and skull radiographic procedures respectively

Pulmonary Metastasis from Rectal Cancer on Chest CT Is Correlated with 3T MRI Primary Tumor Location

International Nuclear Information System (INIS)

Han, Na Yeon; Kim, Min Ju; Park, Beon Jin; Sung, Deuk Jae; Chung, Kyoo Byung; Oh, Yu Whan

2011-01-01

To evaluate the association between the incidence of pulmonary metastasis on chest CT and the location of the primary tumor on rectal MRI. One hundred and nine consecutive patients with rectal adenocarcinoma underwent chest CT and 3T rectal MRI. Two radiologists classified the tumor on MRI as an upper (> 10 cm from the anal verge), mid (5-10 cm), or lower rectal tumor (< 5 cm) by consensus. All chest CT scans were retrospectively reviewed for the presence of metastasis. We used Fisher's exact test to evaluate the correlation between the incidence of pulmonary metastasis with the location of the rectal cancer and the Mantel-Haenszel test to control for local tumor stage. We only included the 60 patients with upper (n = 26) or lower (n = 34) rectal cancer, because of the complicated venous drainage system of the mid rectum. Among these, 9 (15%) showed evidence of pulmonary metastasis on chest CT and almost all (89%, 8/9) patients had lower rectal cancer. The incidence of pulmonary metastasis between the two groups was statistically different (p < 0.05) when local tumor stage was controlled. The incidence of pulmonary metastasis was significantly higher for lower than upper rectal cancers when the T-stage of the tumor was accounted for.

Optimizing radiation exposure for CT localizer radiographs

Energy Technology Data Exchange (ETDEWEB)

Bohrer, Evelyn; Maeder, Ulf; Fiebich, Martin [Univ. of Applied Sciences, Giessen (Germany). Inst. of Medical Physics and Radiation Protection-IMPS; Schaefer, Stefan; Krombach, Gabriele A. [Univ. Hospital Giessen (Germany). Dept. of Radiology; Noel, Peter B. [Technische Univ. Muenchen (Germany). Dept. of Diagnostic and Interventional Radiology

2017-08-01

The trend towards submillisievert CT scans leads to a higher dose fraction of localizer radiographs in CT examinations. The already existing technical capabilities make dose optimization of localizer radiographs worthwhile. Modern CT scanners apply automatic exposure control (AEC) based on attenuation data in such a localizer. Therefore not only this aspect but also the detectability of anatomical landmarks in the localizer for the desired CT scan range adjustment needs to be considered. The effective dose of a head, chest, and abdomen-pelvis localizer radiograph with standard factory settings and user-optimized settings was determined using Monte Carlo simulations. CT examinations of an anthropomorphic phantom were performed using multiple sets of acquisition parameters for the localizer radiograph and the AEC for the subsequent helical CT scan. Anatomical landmarks were defined to assess the image quality of the localizer. CTDI{sub vol} and effective mAs per slice of the helical CT scan were recorded to examine the impact of localizer settings on a helical CT scan. The dose of the localizer radiograph could be decreased by more than 90% while the image quality remained sufficient when selecting the lowest available settings (80 kVp, 20 mA, pa tube position). The tube position during localizer acquisition had a greater impact on the AEC than the reduction of tube voltage and tube current. Except for the use of a pa tube position, all changes of acquisition parameters for the localizer resulted in a decreased total radiation exposure. A dose reduction of CT localizer radiograph is necessary and possible. In the examined CT system there was no negative impact on the modulated helical CT scan when the lowest tube voltage and tube current were used for the localizer.

CT of the chest in the evaluation of idiopathic pulmonary arterial hypertension in children

Energy Technology Data Exchange (ETDEWEB)

Chaudry, Gulraiz [University of Toronto, Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto (Canada); Children' s Hospital Boston, Department of Radiology, Boston, MA (United States); MacDonald, Cathy; Gundogan, Munire; Manson, David [University of Toronto, Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto (Canada); Adatia, Ian [UCSF Children' s Hospital, Department of Pediatric Cardiology, San Francisco, CA (United States)

2007-04-15

Idiopathic pulmonary arterial hypertension (IPAH) is a rare disease in children. By definition it is a diagnosis of exclusion, and CT of the chest is primarily performed to exclude other causes. Previous studies have defined CT features suggestive of the diagnosis of IPAH, but these have all been limited to the adult population. Contrast-enhanced chest CT and high-resolution CT findings in IPAH were evaluated in an attempt to define features consistently seen in children with this condition. The chest CT scans performed at initial presentation were reviewed in 17 children with echocardiographic or angiographic evidence of IPAH. There were nine boys and eight girls, ranging in age from 1 month to 17 years. The extrapulmonary findings included cardiomegaly with right-sided cardiac enlargement, which was seen in 13 children. The central pulmonary arteries were enlarged in 15 children, with peripheral enlargement in two. In six children this resulted in bronchial compression. In addition, mediastinal and hilar lymphadenopathy was noted in three children. Prominent intrapulmonary features included a peripheral vasculopathy, with enlarged tortuous vessels, seen in eight children. Ill-defined ground-glass centrilobular opacities were also noted in eight children, representing the most common parenchymal abnormality. Other findings included septal lines in five, diffuse ground-glass opacification in four and focal hyperlucent zones in three. Mosaic attenuation was seen in one child. A variety of imaging findings are identified in IPAH. Features particularly consistent with the diagnosis include peripheral vasculopathy and centrilobular opacities in the setting of cardiomegaly and central pulmonary arterial enlargement. (orig.)

CT of the chest in the evaluation of idiopathic pulmonary arterial hypertension in children

International Nuclear Information System (INIS)

Chaudry, Gulraiz; MacDonald, Cathy; Gundogan, Munire; Manson, David; Adatia, Ian

2007-01-01

Idiopathic pulmonary arterial hypertension (IPAH) is a rare disease in children. By definition it is a diagnosis of exclusion, and CT of the chest is primarily performed to exclude other causes. Previous studies have defined CT features suggestive of the diagnosis of IPAH, but these have all been limited to the adult population. Contrast-enhanced chest CT and high-resolution CT findings in IPAH were evaluated in an attempt to define features consistently seen in children with this condition. The chest CT scans performed at initial presentation were reviewed in 17 children with echocardiographic or angiographic evidence of IPAH. There were nine boys and eight girls, ranging in age from 1 month to 17 years. The extrapulmonary findings included cardiomegaly with right-sided cardiac enlargement, which was seen in 13 children. The central pulmonary arteries were enlarged in 15 children, with peripheral enlargement in two. In six children this resulted in bronchial compression. In addition, mediastinal and hilar lymphadenopathy was noted in three children. Prominent intrapulmonary features included a peripheral vasculopathy, with enlarged tortuous vessels, seen in eight children. Ill-defined ground-glass centrilobular opacities were also noted in eight children, representing the most common parenchymal abnormality. Other findings included septal lines in five, diffuse ground-glass opacification in four and focal hyperlucent zones in three. Mosaic attenuation was seen in one child. A variety of imaging findings are identified in IPAH. Features particularly consistent with the diagnosis include peripheral vasculopathy and centrilobular opacities in the setting of cardiomegaly and central pulmonary arterial enlargement. (orig.)

Exposing exposure: automated anatomy-specific CT radiation exposure extraction for quality assurance and radiation monitoring.

Science.gov (United States)

Sodickson, Aaron; Warden, Graham I; Farkas, Cameron E; Ikuta, Ichiro; Prevedello, Luciano M; Andriole, Katherine P; Khorasani, Ramin

2012-08-01

To develop and validate an informatics toolkit that extracts anatomy-specific computed tomography (CT) radiation exposure metrics (volume CT dose index and dose-length product) from existing digital image archives through optical character recognition of CT dose report screen captures (dose screens) combined with Digital Imaging and Communications in Medicine attributes. This institutional review board-approved HIPAA-compliant study was performed in a large urban health care delivery network. Data were drawn from a random sample of CT encounters that occurred between 2000 and 2010; images from these encounters were contained within the enterprise image archive, which encompassed images obtained at an adult academic tertiary referral hospital and its affiliated sites, including a cancer center, a community hospital, and outpatient imaging centers, as well as images imported from other facilities. Software was validated by using 150 randomly selected encounters for each major CT scanner manufacturer, with outcome measures of dose screen retrieval rate (proportion of correctly located dose screens) and anatomic assignment precision (proportion of extracted exposure data with correctly assigned anatomic region, such as head, chest, or abdomen and pelvis). The 95% binomial confidence intervals (CIs) were calculated for discrete proportions, and CIs were derived from the standard error of the mean for continuous variables. After validation, the informatics toolkit was used to populate an exposure repository from a cohort of 54 549 CT encounters; of which 29 948 had available dose screens. Validation yielded a dose screen retrieval rate of 99% (597 of 605 CT encounters; 95% CI: 98%, 100%) and an anatomic assignment precision of 94% (summed DLP fraction correct 563 in 600 CT encounters; 95% CI: 92%, 96%). Patient safety applications of the resulting data repository include benchmarking between institutions, CT protocol quality control and optimization, and cumulative

Clinical indications and radiation doses to the conceptus associated with CT imaging in pregnancy: a retrospective study

Energy Technology Data Exchange (ETDEWEB)

Woussen, S.; Vanbeckevoort, D.; Bosmans, H.; Oyen, R. [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Lopez-Rendon, X.; Zanca, F. [University Hospitals Leuven, Department of Imaging and Pathology, Leuven (Belgium)

2016-04-15

To perform an internal audit at a university hospital with the aim of evaluating the number, clinical indication and operating procedure of computed tomography (CT) performed on pregnant patients and of estimating the radiation doses to the conceptus. A retrospective review was conducted of all CT examinations performed in a single centre on pregnant patients between January 2008 and July 2013. The radiation doses to the conceptus were estimated. The results were compared with published data. The number of CT examinations during pregnancy increased from 3-4 per year in 2008-2011 to 11 per year in 2012. The mean estimated conceptus radiation dose was considered negligible for CT of the head and cervical spine, being less than 0.01 mGy, and for CT of the chest, less than 0.1 mGy. The estimated conceptus radiation dose from abdominopelvic CT was on average 28.7 mGy (range 6.7-60.5 mGy). The number of CT scans of pregnant patients increased threefold during the last few years. Most clinical indications and doses were in line with good clinical practice and literature; only in two cases the dose to the conceptus was higher than 50 mGy. (orig.)

Evaluation of automatic image quality assessment in chest CT - A human cadaver study.

Science.gov (United States)

Franck, Caro; De Crop, An; De Roo, Bieke; Smeets, Peter; Vergauwen, Merel; Dewaele, Tom; Van Borsel, Mathias; Achten, Eric; Van Hoof, Tom; Bacher, Klaus

2017-04-01

The evaluation of clinical image quality (IQ) is important to optimize CT protocols and to keep patient doses as low as reasonably achievable. Considering the significant amount of effort needed for human observer studies, automatic IQ tools are a promising alternative. The purpose of this study was to evaluate automatic IQ assessment in chest CT using Thiel embalmed cadavers. Chest CT's of Thiel embalmed cadavers were acquired at different exposures. Clinical IQ was determined by performing a visual grading analysis. Physical-technical IQ (noise, contrast-to-noise and contrast-detail) was assessed in a Catphan phantom. Soft and sharp reconstructions were made with filtered back projection and two strengths of iterative reconstruction. In addition to the classical IQ metrics, an automatic algorithm was used to calculate image quality scores (IQs). To be able to compare datasets reconstructed with different kernels, the IQs values were normalized. Good correlations were found between IQs and the measured physical-technical image quality: noise (ρ=-1.00), contrast-to-noise (ρ=1.00) and contrast-detail (ρ=0.96). The correlation coefficients between IQs and the observed clinical image quality of soft and sharp reconstructions were 0.88 and 0.93, respectively. The automatic scoring algorithm is a promising tool for the evaluation of thoracic CT scans in daily clinical practice. It allows monitoring of the image quality of a chest protocol over time, without human intervention. Different reconstruction kernels can be compared after normalization of the IQs. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Research on the radiation doses to adults receiving from main types of medical X-ray CT examinations

International Nuclear Information System (INIS)

Gao Linfeng; Wang Bin; Yao Jie; Qian Aijun; Zheng Junzheng; Zhuo Weihai; Qu Liangyong

2013-01-01

To study and master the doses to examinees receiving from the wide spread X-CT examinations, is a key issue for strengthening the medical radiation protection. In the studies of the medical exposure levels during the Eleventh Five-Year Plan period in Shanghai, based on the brands of X-CT scanners and their distributions in different levels of hospitals, a total of 45 sets (about 30% of all) of scanners were selected for the field study. Among the 8 commonly performed examinations, the scan parameters and their relevant dosimetry information for 500 adults were collected, and their typical effective doses were estimated with the dose conversion factors. The results showed that the averages of weighted CT dose index (CTDI w ) were 55.4, 12.5 and 18.4 mGy, and the dose length products (DLP) were averaged to be 603, 294 and 415 mGy·cm, for the skull, chest and abdomen X-CT scans, respectively. The typical effective doses were estimated to be 1.4, 5.3, and 7.5 mSv for adults in the head, chest and abdomen X-CT scans, respectively. The values of CTDI w for skull scans were generally higher than those for the ear canal, eye, or sinus examinations. It is clear that the optimization between the image quality and the radiation dose should be further strengthened. Particular attentions should be paid in selecting the scanning parameters for various types of X-CT scans, and the diagnostic reference levels for X-CT examinations should be continuously improved. (authors)

The evaluation of cardiac tamponade risk in patients with pericardial effusion detected by non-gated chest CT.

Science.gov (United States)

Ohta, Yasutoshi; Miyoshi, Fuminori; Kaminou, Toshio; Kaetsu, Yasuhiro; Ogawa, Toshihide

2016-05-01

Although pericardial effusion is often identified using non-gated chest computed tomography (CT), findings predictive of cardiac tamponade have not been adequately established. To determine the findings predictive of clinical cardiac tamponade in patients with moderate to large pericardial effusion using non-gated chest CT. We performed a retrospective analysis of 134 patients with moderate to large pericardial effusion who were identified from among 4581 patients who underwent non-gated chest CT. Cardiac structural changes, including right ventricular outflow tract (RVOT), were qualitatively evaluated. The inferior vena cava ratio with hepatic (IVCupp) and renal portions (IVClow) and effusion size were measured. The diagnostic performance of each structural change was calculated, and multivariate analysis was used to determine the predictors of cardiac tamponade. Of the 134 patients (mean age, 70.3 years; 64 men), 37 (28%) had cardiac tamponade. The sensitivity and specificity were 76% and 74% for RVOT compression; 87% and 84% for an IVClow ratio ≥0.77; and 60% and 77% for an effusion size ≥25.5 mm, respectively. Multivariate logistic regression analysis demonstrated that RVOT compression, an IVClow ratio ≥0.77, and an effusion size ≥25.5 mm were independent predictors of cardiac tamponade. The combination of these three CT findings had a sensitivity, specificity, and accuracy of 81%, 95%, and 91%, respectively. In patients with moderate to large pericardial effusion, non-gated chest CT provides additional information for predicting cardiac tamponade. © The Foundation Acta Radiologica 2015.

Pediatric CT: implementation of ASIR for substantial radiation dose reduction while maintaining pre-ASIR image noise.

Science.gov (United States)

Brady, Samuel L; Moore, Bria M; Yee, Brian S; Kaufman, Robert A

2014-01-01

To determine a comprehensive method for the implementation of adaptive statistical iterative reconstruction (ASIR) for maximal radiation dose reduction in pediatric computed tomography (CT) without changing the magnitude of noise in the reconstructed image or the contrast-to-noise ratio (CNR) in the patient. The institutional review board waived the need to obtain informed consent for this HIPAA-compliant quality analysis. Chest and abdominopelvic CT images obtained before ASIR implementation (183 patient examinations; mean patient age, 8.8 years ± 6.2 [standard deviation]; range, 1 month to 27 years) were analyzed for image noise and CNR. These measurements were used in conjunction with noise models derived from anthropomorphic phantoms to establish new beam current-modulated CT parameters to implement 40% ASIR at 120 and 100 kVp without changing noise texture or magnitude. Image noise was assessed in images obtained after ASIR implementation (492 patient examinations; mean patient age, 7.6 years ± 5.4; range, 2 months to 28 years) the same way it was assessed in the pre-ASIR analysis. Dose reduction was determined by comparing size-specific dose estimates in the pre- and post-ASIR patient cohorts. Data were analyzed with paired t tests. With 40% ASIR implementation, the average relative dose reduction for chest CT was 39% (2.7/4.4 mGy), with a maximum reduction of 72% (5.3/18.8 mGy). The average relative dose reduction for abdominopelvic CT was 29% (4.8/6.8 mGy), with a maximum reduction of 64% (7.6/20.9 mGy). Beam current modulation was unnecessary for patients weighing 40 kg or less. The difference between 0% and 40% ASIR noise magnitude was less than 1 HU, with statistically nonsignificant increases in patient CNR at 100 kVp of 8% (15.3/14.2; P = .41) for chest CT and 13% (7.8/6.8; P = .40) for abdominopelvic CT. Radiation dose reduction at pediatric CT was achieved when 40% ASIR was implemented as a dose reduction tool only; no net change to the magnitude

Study of dosimetric quantities applied to patient undergoing routine chest examinations by computed tomography

International Nuclear Information System (INIS)

Gonzaga, Natalia Barbosa

2012-01-01

The radiological protection system has established a standard to protect persons against the harmful effects caused by ionizing radiation that is based on the justification, optimization and dose limitation principles. The increasing use of radiation in medicine and the related risks have stressed the discussion on patient radiation protection. The computed tomography (CT) is the diagnostic radiology technique that most contributes to patient doses and it requires optimization efforts. Diagnostic reference levels (DRL) has been established in many countries in terms of CT dosimetric quantities; in Brazil, the DRLs are still under investigation since the culture of patient protection is not very strong yet. The objective of this work was to investigate the dosimetric and protection quantities related to patients undergoing CT routine chest examinations. The ImPACT CT, CT Expo and ImpactDose softwares were used for calculations of the weight and volumetric air-kerma indexes (CW and CVOL), the air kerma - length product (P K,L ), organ equivalent dose (H T ) and the effective dose (E) for CT routine chest protocols in 19 tomographs in Belo Horizonte city. The CT Expo was selected to be validated against experimental measurements in three hospitals with thermoluminescent dosimeters and CT pencil ionization chamber in anthropomorphic and standard CT body phantoms. Experimental and calculated results indicated differences up to 97% for H T and E and acceptable agreement for C W ,C VOL and P K,L . All data from 19 tomographs showed that local DRLs for CT routine chest examinations may be chosen smaller than DRLs adopted in other countries; this would contribute to increase the radiological protection of patients. (author)

Practical applications of digital tomosynthesis of the chest

International Nuclear Information System (INIS)

Galea, A.; Durran, A.; Adlan, T.; Gay, D.; Riordan, R.; Dubbins, P.; Williams, M.P.

2014-01-01

Digital tomosynthesis is a radiographic technique that generates a number of coronal raw images of a patient from a single pass of the x-ray tube. Tomosynthesis provides some of the tomographic benefits of computed tomography (CT), but at a much lower dose of radiation and cost when compared to CT. This review illustrates the range of practical applications of digital tomosynthesis of the chest

Classification of pulmonary emphysema from chest CT scans using integral geometry descriptors

Science.gov (United States)

van Rikxoort, E. M.; Goldin, J. G.; Galperin-Aizenberg, M.; Brown, M. S.

2011-03-01

To gain insight into the underlying pathways of emphysema and monitor the effect of treatment, methods to quantify and phenotype the different types of emphysema from chest CT scans are of crucial importance. Current standard measures rely on density thresholds for individual voxels, which is influenced by inspiration level and does not take into account the spatial relationship between voxels. Measures based on texture analysis do take the interrelation between voxels into account and therefore might be useful for distinguishing different types of emphysema. In this study, we propose to use Minkowski functionals combined with rotation invariant Gaussian features to distinguish between healthy and emphysematous tissue and classify three different types of emphysema. Minkowski functionals characterize binary images in terms of geometry and topology. In 3D, four Minkowski functionals are defined. By varying the threshold and size of neighborhood around a voxel, a set of Minkowski functionals can be defined for each voxel. Ten chest CT scans with 1810 annotated regions were used to train the method. A set of 108 features was calculated for each training sample from which 10 features were selected to be most informative. A linear discriminant classifier was trained to classify each voxel in the lungs into a subtype of emphysema or normal lung. The method was applied to an independent test set of 30 chest CT scans with varying amounts and types of emphysema with 4347 annotated regions of interest. The method is shown to perform well, with an overall accuracy of 95%.

Which Iodine concentration in chest CT? - A prospective study in 300 patients

Energy Technology Data Exchange (ETDEWEB)

Muehlenbruch, Georg [RWTH Aachen University Hospital, Department of Diagnostic and Interventional Radiology, Aachen (Germany); University Hospital, RWTH Aachen University, Aachen (Germany); Behrendt, Florian F.; Eddahabi, Mohammed A.; Das, Marco; Guenther, Rolf W.; Mahnken, Andreas H. [RWTH Aachen University Hospital, Department of Diagnostic and Interventional Radiology, Aachen (Germany); Knackstedt, Christian [RWTH Aachen University Hospital, Department of Cardiology, Pulmonology and Angiology, Aachen (Germany); Stanzel, Sven [RWTH Aachen University Hospital, Institute of Medical Statistics, Aachen (Germany); Seidensticker, Peter [Bayer Schering Pharma AG, Berlin (Germany); Wildberger, Joachim E. [University Hospital Maastricht, Department of Radiology, Maastricht (Netherlands)

2008-12-15

In computed tomography(CT) several contrast media with different iodine concentrations are available. The aim of this study is to prospectively compare contrast media with iodine concentrations of 300, 370 and 400 mg iodine/ml for chest- CT. 300 consecutive patients were prospectively enrolled, under a waiver of the local ethics committee. The first (second, third) 100 patients, received contrast medium with 300(370, 400)mg iodine/ml. Injection protocols were adapted for an identical iodine delivery rate(1.3 mg/s) and total iodine load(33 g) for all three groups. Standardized MDCT of the chest (16 x 0.75 mm, 120 kVp, 100 mAseff.) was performed. Intravascular attenuation values were measured in the pulmonary trunk and the ascending aorta; subjective image quality was rated on a 3-point-scale. Discomfort during and after injection was evaluated. There were no statistically significant differences in contrast enhancement comparing the three contrast media at the pulmonary trunk(p = 0.3198) and at the ascending aorta(p = 0.0840). Image quality(p = 0.0176) and discomfort during injection(p = 0.7034) were comparable for all groups. General discomfort after injection of contrast media with 300 mg iodine/ml was statistically significant higher compared to 370 mg iodine/ml(p = 0.00019). Given identical iodine delivery rates of 1.3 g/s and iodine loads of 33 g, contrast media with concentrations of 300, 370 and 400 mg iodine/ml do not result in different intravascular enhancement in chest-CT. (orig.)

Dense volumetric detection and segmentation of mediastinal lymph nodes in chest CT images

Science.gov (United States)

Oda, Hirohisa; Roth, Holger R.; Bhatia, Kanwal K.; Oda, Masahiro; Kitasaka, Takayuki; Iwano, Shingo; Homma, Hirotoshi; Takabatake, Hirotsugu; Mori, Masaki; Natori, Hiroshi; Schnabel, Julia A.; Mori, Kensaku

2018-02-01

We propose a novel mediastinal lymph node detection and segmentation method from chest CT volumes based on fully convolutional networks (FCNs). Most lymph node detection methods are based on filters for blob-like structures, which are not specific for lymph nodes. The 3D U-Net is a recent example of the state-of-the-art 3D FCNs. The 3D U-Net can be trained to learn appearances of lymph nodes in order to output lymph node likelihood maps on input CT volumes. However, it is prone to oversegmentation of each lymph node due to the strong data imbalance between lymph nodes and the remaining part of the CT volumes. To moderate the balance of sizes between the target classes, we train the 3D U-Net using not only lymph node annotations but also other anatomical structures (lungs, airways, aortic arches, and pulmonary arteries) that can be extracted robustly in an automated fashion. We applied the proposed method to 45 cases of contrast-enhanced chest CT volumes. Experimental results showed that 95.5% of lymph nodes were detected with 16.3 false positives per CT volume. The segmentation results showed that the proposed method can prevent oversegmentation, achieving an average Dice score of 52.3 +/- 23.1%, compared to the baseline method with 49.2 +/- 23.8%, respectively.

Scan Quality and Entrance Skin Dose in Thoracic CT: A Comparison between Bismuth Breast Shield and Posteriorly Centered Partial CT Scans

International Nuclear Information System (INIS)

Tappouni, Rafel; Mathers, Bradley

2012-01-01

Objectives. To compare the effectiveness of the bismuth breast shield and partial CT scan in reducing entrance skin dose and to evaluate the effect of the breast shield on image quality (IQ). Methods. Nanodots were placed on an adult anthropomorphic phantom. Standard chest CT, CT with shield, and partial CT were performed. Nanodot readings and effective doses were recorded. 50 patients with chest CTs obtained both with and without breast shields were reviewed. IQ was evaluated by two radiologists and by measuring Hounsfield units (HUs) and standard deviation (SD) of HU in anterior subcutaneous region. Results. Breast shield and the partial CT scans reduced radiation to the anterior chest by 38% and 16%, respectively. Partial CT increased dose to the posterior chest by 37% and effective dose by 8%. Change in IQ in shield CT was observed in the anterior chest wall. Significant change in IQ was observed in 5/50 cases. The shield caused an increase of 20 HU (P = 0.021) and a 1.86 reduction in SD of HU (P = 0.027) in the anterior compared to posterior subcutaneous regions. Summary. Bismuth breast shield is more effective than the partial CT in reducing entrance skin dose while maintaining image quality

CT of the chest with model-based, fully iterative reconstruction: comparison with adaptive statistical iterative reconstruction.

Science.gov (United States)

Ichikawa, Yasutaka; Kitagawa, Kakuya; Nagasawa, Naoki; Murashima, Shuichi; Sakuma, Hajime

2013-08-09

The recently developed model-based iterative reconstruction (MBIR) enables significant reduction of image noise and artifacts, compared with adaptive statistical iterative reconstruction (ASIR) and filtered back projection (FBP). The purpose of this study was to evaluate lesion detectability of low-dose chest computed tomography (CT) with MBIR in comparison with ASIR and FBP. Chest CT was acquired with 64-slice CT (Discovery CT750HD) with standard-dose (5.7 ± 2.3 mSv) and low-dose (1.6 ± 0.8 mSv) conditions in 55 patients (aged 72 ± 7 years) who were suspected of lung disease on chest radiograms. Low-dose CT images were reconstructed with MBIR, ASIR 50% and FBP, and standard-dose CT images were reconstructed with FBP, using a reconstructed slice thickness of 0.625 mm. Two observers evaluated the image quality of abnormal lung and mediastinal structures on a 5-point scale (Score 5 = excellent and score 1 = non-diagnostic). The objective image noise was also measured as the standard deviation of CT intensity in the descending aorta. The image quality score of enlarged mediastinal lymph nodes on low-dose MBIR CT (4.7 ± 0.5) was significantly improved in comparison with low-dose FBP and ASIR CT (3.0 ± 0.5, p = 0.004; 4.0 ± 0.5, p = 0.02, respectively), and was nearly identical to the score of standard-dose FBP image (4.8 ± 0.4, p = 0.66). Concerning decreased lung attenuation (bulla, emphysema, or cyst), the image quality score on low-dose MBIR CT (4.9 ± 0.2) was slightly better compared to low-dose FBP and ASIR CT (4.5 ± 0.6, p = 0.01; 4.6 ± 0.5, p = 0.01, respectively). There were no significant differences in image quality scores of visualization of consolidation or mass, ground-glass attenuation, or reticular opacity among low- and standard-dose CT series. Image noise with low-dose MBIR CT (11.6 ± 1.0 Hounsfield units (HU)) were significantly lower than with low-dose ASIR (21.1 ± 2.6 HU, p standard-dose FBP CT (16.6 ± 2.3 HU, p 70%, MBIR can provide

What did we learn from two decades of chest computed tomography in cystic fibrosis?

International Nuclear Information System (INIS)

Tiddens, Harm A.W.M.; Rosenow, Tim

2014-01-01

Despite our current treatment, many cystic fibrosis (CF) patients still show progressive bronchiectasis and small airways disease. Adequate detection and monitoring of progression of these structural abnormalities is needed to personalize treatment to the severity of CF lung disease of the patient. Chest computed tomography (CT) is the gold standard to diagnose and monitor bronchiectasis. Many studies have been done to validate the role of chest CT in CF and to improve the protocols. From these studies it became clear that for correct interpretation of the severity of bronchiectasis and small airways disease standardization of lung volume for the inspiratory and expiratory CT scan acquisition is needed. The risk related to the radiation exposure of a chest CT scan every second year is considered low. Automated and quantitative image analysis systems are developed to improve the reliability and sensitivity of assessments of structural lung changes in CF, particularly in early life. In this paper an overview is given of the lessons learned from two decades of monitoring CF lung disease using chest CT. (orig.)

What did we learn from two decades of chest computed tomography in cystic fibrosis?

Energy Technology Data Exchange (ETDEWEB)

Tiddens, Harm A.W.M. [Erasmus MC-Sophia Children' s Hospital, Department of Pediatric Pulmonology, Rotterdam (Netherlands); Erasmus MC, Department of Radiology, Rotterdam (Netherlands); Rosenow, Tim [Erasmus MC-Sophia Children' s Hospital, Department of Pediatric Pulmonology, Rotterdam (Netherlands); The University of Western Australia, Telethon Institute for Child Health Research, Perth (Australia); The University of Western Australia, School of Paediatrics and Child Health Research, Perth (Australia)

2014-12-15

Despite our current treatment, many cystic fibrosis (CF) patients still show progressive bronchiectasis and small airways disease. Adequate detection and monitoring of progression of these structural abnormalities is needed to personalize treatment to the severity of CF lung disease of the patient. Chest computed tomography (CT) is the gold standard to diagnose and monitor bronchiectasis. Many studies have been done to validate the role of chest CT in CF and to improve the protocols. From these studies it became clear that for correct interpretation of the severity of bronchiectasis and small airways disease standardization of lung volume for the inspiratory and expiratory CT scan acquisition is needed. The risk related to the radiation exposure of a chest CT scan every second year is considered low. Automated and quantitative image analysis systems are developed to improve the reliability and sensitivity of assessments of structural lung changes in CF, particularly in early life. In this paper an overview is given of the lessons learned from two decades of monitoring CF lung disease using chest CT. (orig.)

Chest X-ray and chest CT findings in patients diagnosed with pulmonary tuberculosis following solid organ transplantation: a systematic review.

Science.gov (United States)

Giacomelli, Irai Luis; Schuhmacher Neto, Roberto; Marchiori, Edson; Pereira, Marisa; Hochhegger, Bruno

2018-04-01

The objective of this systematic review was to select articles including chest X-ray or chest CT findings in patients who developed pulmonary tuberculosis following solid organ transplantation (lung, kidney, or liver). The following search terms were used: "tuberculosis"; "transplants"; "transplantation"; "mycobacterium"; and "lung". The databases used in this review were PubMed and the Brazilian Biblioteca Virtual em Saúde (Virtual Health Library). We selected articles in English, Portuguese, or Spanish, regardless of the year of publication, that met the selection criteria in their title, abstract, or body of text. Articles with no data on chest CT or chest X-ray findings were excluded, as were those not related to solid organ transplantation or pulmonary tuberculosis. We selected 29 articles involving a collective total of 219 patients. The largest samples were in studies conducted in Brazil and South Korea (78 and 35 patients, respectively). The imaging findings were subdivided into five common patterns. The imaging findings varied depending on the transplanted organ in these patients. In liver and lung transplant recipients, the most common pattern was the classic one for pulmonary tuberculosis (cavitation and "tree-in-bud" nodules), which is similar to the findings for pulmonary tuberculosis in the general population. The proportion of cases showing a miliary pattern and lymph node enlargement, which is most similar to the pattern seen in patients coinfected with tuberculosis and HIV, was highest among the kidney transplant recipients. Further studies evaluating clinical data, such as immunosuppression regimens, are needed in order to improve understanding of the distribution of these imaging patterns in this population.

CT findings of foreign bodies in the chest: a pictorial essay

International Nuclear Information System (INIS)

Park, Sang Hyun; Kim, Young Tong; Jou, Sung Shick; Shin, Hyung Cheol

2008-01-01

The most common causes of tracheobronchial foreign bodies are peanuts in children, and meat and dentures in adults. The most common causes of esophageal foreign bodies are coins in children and meat in adults. It is passable to diagnose a foreign body by visualization on a chest radiograph, if the foreign bodies are radio opaque. However, if the foreign bodies are radiolucent and the patients do not remember the history of aspiration, it is important to evaluate CT findings for foreign bodies and their complications. We describe the CT findings of various thoracic foreign bodies in children and adults

CT findings of foreign bodies in the chest: a pictorial essay

Energy Technology Data Exchange (ETDEWEB)

Park, Sang Hyun; Kim, Young Tong; Jou, Sung Shick; Shin, Hyung Cheol [Cheonan Hospital, Soonchunhyang University, Cheonan (Korea, Republic of)

2008-05-15

The most common causes of tracheobronchial foreign bodies are peanuts in children, and meat and dentures in adults. The most common causes of esophageal foreign bodies are coins in children and meat in adults. It is passable to diagnose a foreign body by visualization on a chest radiograph, if the foreign bodies are radio opaque. However, if the foreign bodies are radiolucent and the patients do not remember the history of aspiration, it is important to evaluate CT findings for foreign bodies and their complications. We describe the CT findings of various thoracic foreign bodies in children and adults.

Adenosine-stress dynamic real-time myocardial perfusion CT and adenosine-stress first-pass dual-energy myocardial perfusion CT for the assessment of acute chest pain: Initial results

Energy Technology Data Exchange (ETDEWEB)

Weininger, Markus [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Department of Medicine, Division of Cardiology, Medical University of South Carolina, Charleston, SC (United States); Ramachandra, Ashok [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Fink, Christian [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Rowe, Garrett W.; Costello, Philip [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Henzler, Thomas [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany)

2012-12-15

Purpose: Recent innovations in CT enable the evolution from mere morphologic imaging to dynamic and functional testing. We describe our initial experience performing myocardial stress perfusion CT in a clinical population with acute chest pain. Methods and materials: Myocardial stress perfusion CT was performed on twenty consecutive patients (15 men, 5 women; mean age 65 ± 8 years) who presented with acute chest pain and were clinically referred for stress/rest SPECT and cardiac MRI. Prior to CT each patient was randomly assigned either to Group A or to Group B in a consecutive order (10 patients per group). Group A underwent adenosine-stress dynamic real-time myocardial perfusion CT using a novel “shuttle” mode on a 2nd generation dual-source CT. Group B underwent adenosine-stress first-pass dual-energy myocardial perfusion CT using the same CT scanner in dual-energy mode. Two experienced observers visually analyzed all CT perfusion studies. CT findings were compared with MRI and SPECT. Results: In Group A 149/170 myocardial segments (88%) could be evaluated. Real-time perfusion CT (versus SPECT) had 86% (84%) sensitivity, 98% (92%) specificity, 94% (88%) positive predictive value, and 96% (92%) negative predictive value in comparison with perfusion MRI for the detection of myocardial perfusion defects. In Group B all myocardial segments were available for analysis. Compared with MRI, dual-energy myocardial perfusion CT (versus SPECT) had 93% (94%) sensitivity, 99% (98%) specificity, 92% (88%) positive predictive value, and 96% (94%) negative predictive value for detecting hypoperfused myocardial segments. Conclusion: Our results suggest the clinical feasibility of myocardial perfusion CT imaging in patients with acute chest pain. Compared to MRI and SPECT both, dynamic real-time perfusion CT and first-pass dual-energy perfusion CT showed good agreement for the detection of myocardial perfusion defects.

Adenosine-stress dynamic real-time myocardial perfusion CT and adenosine-stress first-pass dual-energy myocardial perfusion CT for the assessment of acute chest pain: Initial results

International Nuclear Information System (INIS)

Weininger, Markus; Schoepf, U. Joseph; Ramachandra, Ashok; Fink, Christian; Rowe, Garrett W.; Costello, Philip; Henzler, Thomas

2012-01-01

Purpose: Recent innovations in CT enable the evolution from mere morphologic imaging to dynamic and functional testing. We describe our initial experience performing myocardial stress perfusion CT in a clinical population with acute chest pain. Methods and materials: Myocardial stress perfusion CT was performed on twenty consecutive patients (15 men, 5 women; mean age 65 ± 8 years) who presented with acute chest pain and were clinically referred for stress/rest SPECT and cardiac MRI. Prior to CT each patient was randomly assigned either to Group A or to Group B in a consecutive order (10 patients per group). Group A underwent adenosine-stress dynamic real-time myocardial perfusion CT using a novel “shuttle” mode on a 2nd generation dual-source CT. Group B underwent adenosine-stress first-pass dual-energy myocardial perfusion CT using the same CT scanner in dual-energy mode. Two experienced observers visually analyzed all CT perfusion studies. CT findings were compared with MRI and SPECT. Results: In Group A 149/170 myocardial segments (88%) could be evaluated. Real-time perfusion CT (versus SPECT) had 86% (84%) sensitivity, 98% (92%) specificity, 94% (88%) positive predictive value, and 96% (92%) negative predictive value in comparison with perfusion MRI for the detection of myocardial perfusion defects. In Group B all myocardial segments were available for analysis. Compared with MRI, dual-energy myocardial perfusion CT (versus SPECT) had 93% (94%) sensitivity, 99% (98%) specificity, 92% (88%) positive predictive value, and 96% (94%) negative predictive value for detecting hypoperfused myocardial segments. Conclusion: Our results suggest the clinical feasibility of myocardial perfusion CT imaging in patients with acute chest pain. Compared to MRI and SPECT both, dynamic real-time perfusion CT and first-pass dual-energy perfusion CT showed good agreement for the detection of myocardial perfusion defects.

TRIAGE OF PATIENTS TO ANGIOGRAPHY FOR DETECTION OF AORTIC RUPTURE AFTER BLUNT CHEST TRAUMA - COST-EFFECTIVENESS ANALYSIS OF USING CT

NARCIS (Netherlands)

HUNINK, MGM; BOS, JJ

OBJECTIVE. The purpose of this study was to evaluate the cost-effectiveness of dynamic chest CT, compared with plain chest radiography and immediate angiography, in deciding when angiography should be performed in hemodynamically stable patients with suspected aortic rupture after blunt chest

Radiation fibrosis : differentiation from true hilar mass on plain chest film

International Nuclear Information System (INIS)

Baik, Jun Hyun; Ahn, Kook Jin; Park, Seog Hee; Shinn, Kyung Sub

1996-01-01

Radiation-induced fibrotic mass might masquerade as a true hilar tumor mass on a plain chest radiograph. We attempted to differentiate radiation fibrosis from a true hilar tumor using only a plain radiograph. Plain chest radiographs were obtained from seven patients who had developed radiation fibrosis simulating hilar mass after radiation therapy for lung cancer, and from 19 patients with lung cancer, a comparison group, who had not received radiation therapy. They were reviewed for the obliteration of the overlapped mediastinal and hilar anatomical silhouettes by the mass : pulmonary artery, heart or aorta border, and paraspinal line. All seven patients with radiation-induced fibrotic mass(bilateral lesion in two patients) showed obliteration of all three overlapped anatomical silhouettes of the mediastinum and hilum on chest radiographs. In the comparison group of 19 patients with a true hilar mass, there was, however, no case which demonstrated obliteration of all landmarks, Obliteration of all anatomical landmarks at the hilum and mediastinum may be a helpful clue in the differential diagnosis of radiation-induced fibrotic mass from true hilar mass on a plain radiograph, particularly when clinical information on previous radiation therapy is unavailable

Quantification of Emphysema with a Three-Dimensional Chest CT Scan: Correlation with the Visual Emphysema Scoring on Chest CT, Pulmonary Function Tests and Dyspnea Severity

Energy Technology Data Exchange (ETDEWEB)

Park, Hyun Jeong; Hwang, Jung Hwa [Dept. of Radiology, Soonchunhyang University Seoul Hospital, Seoul (Korea, Republic of)

2011-09-15

We wanted to prospectively evaluate the correlation between the quantification of emphysema using 3D CT densitometry with the visual emphysema score, pulmonary function tests (PFT) and the dyspnea score in patients with chronic obstructive pulmonary disease (COPD). Non-enhanced chest CT with 3D reconstruction was performed in 28 men with COPD (age 54-88 years). With histogram analysis, the total lung volume, mean lung density and proportion of low attenuation lung volume below predetermined thresholds were measured. The CT parameters were compared with the visual emphysema score, the PFT and the dyspnea score. A low attenuation lung volume below -950 HU was well correlated with the DLco and FEV{sub 1}/FVC. A Low attenuation lung volume below -950 HU and -930 HU was correlated with visual the emphysema score. A low attenuation lung volume below -950 HU was correlated with the dyspnea score, although the correlations between the other CT parameters and the dyspnea score were not significant. Objective quantification of emphysema using 3D CT densitometry was correlated with the visual emphysema score. A low attenuation lung volume below -950 HU was correlated with the DLco, the FEV{sub 1}/FVC and the dyspnea score.

Quantification of Emphysema with a Three-Dimensional Chest CT Scan: Correlation with the Visual Emphysema Scoring on Chest CT, Pulmonary Function Tests and Dyspnea Severity

International Nuclear Information System (INIS)

Park, Hyun Jeong; Hwang, Jung Hwa

2011-01-01

We wanted to prospectively evaluate the correlation between the quantification of emphysema using 3D CT densitometry with the visual emphysema score, pulmonary function tests (PFT) and the dyspnea score in patients with chronic obstructive pulmonary disease (COPD). Non-enhanced chest CT with 3D reconstruction was performed in 28 men with COPD (age 54-88 years). With histogram analysis, the total lung volume, mean lung density and proportion of low attenuation lung volume below predetermined thresholds were measured. The CT parameters were compared with the visual emphysema score, the PFT and the dyspnea score. A low attenuation lung volume below -950 HU was well correlated with the DLco and FEV 1 /FVC. A Low attenuation lung volume below -950 HU and -930 HU was correlated with visual the emphysema score. A low attenuation lung volume below -950 HU was correlated with the dyspnea score, although the correlations between the other CT parameters and the dyspnea score were not significant. Objective quantification of emphysema using 3D CT densitometry was correlated with the visual emphysema score. A low attenuation lung volume below -950 HU was correlated with the DLco, the FEV 1 /FVC and the dyspnea score.

Pediatric chest imaging. Chest imaging in infants and children. 2. rev. ed.

Energy Technology Data Exchange (ETDEWEB)

Lucaya, Javier [Vall d' Hebron Hospitals, Barcelona (Spain). Dept. of Pediatric Radiology and Inst. of Diagnostic Imaging; Hospital Quiron, Barcelona (Spain). Dept. of Radiology; Strife, Janet L. (eds.) [Cincinnati Univ. Coll. of Medicine, Cincinnati, OH (United States). Dept. of Radiology Cincinnati Children' s Hospital Medical Center

2008-07-01

Imaging of the pediatric chest continues to evolve rapidly. All chapters in this 2nd edition of Pediatric Chest Imaging have been extensively updated, with additional disease-specific information and numerous new illustrations. The book thus presents the state of the art in the diagnosis of pediatric chest disorders, highlighting the role played by advanced technology. As the conventional features of most of these disorders are extremely well known, special attention is devoted to the technical aspects of the modern imaging modalities, their indications, and the diagnostic information that they supply. Individual chapters focus on chest ultrasound, nuclear medicine imaging, high-resolution chest CT, helical CT, and pediatric cardiac CT and pediatric cardiacMRI. Others are directed towards specific disorders, including congenital malformations of the chest, chest tumors, pulmonary infection, trauma, the lung in systemic diseases, the pediatric airway, foreign bodies, the thymus, and the chest wall. Without exception, the authors of this book are internationally known specialists with great expertise in the field. This book will serve as a handy, superbly illustrated reference for all who routinely image children, as well as for those who need access to information on how best to image them. (orig.)

Iterative metal artefact reduction (MAR) in postsurgical chest CT: comparison of three iMAR-algorithms.

Science.gov (United States)

Aissa, Joel; Boos, Johannes; Sawicki, Lino Morris; Heinzler, Niklas; Krzymyk, Karl; Sedlmair, Martin; Kröpil, Patric; Antoch, Gerald; Thomas, Christoph

2017-11-01

The purpose of this study was to evaluate the impact of three novel iterative metal artefact (iMAR) algorithms on image quality and artefact degree in chest CT of patients with a variety of thoracic metallic implants. 27 postsurgical patients with thoracic implants who underwent clinical chest CT between March and May 2015 in clinical routine were retrospectively included. Images were retrospectively reconstructed with standard weighted filtered back projection (WFBP) and with three iMAR algorithms (iMAR-Algo1 = Cardiac algorithm, iMAR-Algo2 = Pacemaker algorithm and iMAR-Algo3 = ThoracicCoils algorithm). The subjective and objective image quality was assessed. Averaged over all artefacts, artefact degree was significantly lower for the iMAR-Algo1 (58.9 ± 48.5 HU), iMAR-Algo2 (52.7 ± 46.8 HU) and the iMAR-Algo3 (51.9 ± 46.1 HU) compared with WFBP (91.6 ± 81.6 HU, p algorithms, respectively. iMAR-Algo2 and iMAR-Algo3 reconstructions decreased mild and moderate artefacts compared with WFBP and iMAR-Algo1 (p algorithms led to a significant reduction of metal artefacts and increase in overall image quality compared with WFBP in chest CT of patients with metallic implants in subjective and objective analysis. The iMARAlgo2 and iMARAlgo3 were best for mild artefacts. IMARAlgo1 was superior for severe artefacts. Advances in knowledge: Iterative MAR led to significant artefact reduction and increase image-quality compared with WFBP in CT after implementation of thoracic devices. Adjusting iMAR-algorithms to patients' metallic implants can help to improve image quality in CT.

Pediatric cT: Implementation of ASIR for Substantial Radiation Dose Reduction While Maintaining Pre-ASIR Image Noise1

Science.gov (United States)

Brady, Samuel L.; Moore, Bria M.; Yee, Brian S.; Kaufman, Robert A.

2015-01-01

Purpose To determine a comprehensive method for the implementation of adaptive statistical iterative reconstruction (ASIR) for maximal radiation dose reduction in pediatric computed tomography (CT) without changing the magnitude of noise in the reconstructed image or the contrast-to-noise ratio (CNR) in the patient. Materials and Methods The institutional review board waived the need to obtain informed consent for this HIPAA-compliant quality analysis. Chest and abdominopelvic CT images obtained before ASIR implementation (183 patient examinations; mean patient age, 8.8 years ± 6.2 [standard deviation]; range, 1 month to 27 years) were analyzed for image noise and CNR. These measurements were used in conjunction with noise models derived from anthropomorphic phantoms to establish new beam current–modulated CT parameters to implement 40% ASIR at 120 and 100 kVp without changing noise texture or magnitude. Image noise was assessed in images obtained after ASIR implementation (492 patient examinations; mean patient age, 7.6 years ± 5.4; range, 2 months to 28 years) the same way it was assessed in the pre-ASIR analysis. Dose reduction was determined by comparing size-specific dose estimates in the pre- and post-ASIR patient cohorts. Data were analyzed with paired t tests. Results With 40% ASIR implementation, the average relative dose reduction for chest CT was 39% (2.7/4.4 mGy), with a maximum reduction of 72% (5.3/18.8 mGy). The average relative dose reduction for abdominopelvic CT was 29% (4.8/6.8 mGy), with a maximum reduction of 64% (7.6/20.9 mGy). Beam current modulation was unnecessary for patients weighing 40 kg or less. The difference between 0% and 40% ASIR noise magnitude was less than 1 HU, with statistically nonsignificant increases in patient CNR at 100 kVp of 8% (15.3/14.2; P = .41) for chest CT and 13% (7.8/6.8; P = .40) for abdominopelvic CT. Conclusion Radiation dose reduction at pediatric CT was achieved when 40% ASIR was implemented as a dose

Accuracy of chest radiography versus chest computed tomography in hemodynamically stable patients with blunt chest trauma

Directory of Open Access Journals (Sweden)

Chardoli Mojtaba

2013-12-01

Full Text Available 【Abstract】 Objective: Thoracic injuries are respon- sible for 25% of deaths of blunt traumas. Chest X-ray (CXR is the first diagnostic method in patients with blunt trauma. The aim of this study was to detect the accuracy of CXR versus chest computed tomograpgy (CT in hemodynami- cally stable patients with blunt chest trauma. Methods: Study was conducted at the emergency department of Sina Hospital from March 2011 to March 2012. Hemodynamically stable patients with at least 16 years of age who had blunt chest trauma were included. All patients underwent the same diagnostic protocol which consisted of physical examination, CXR and CT scan respectively. Results: Two hundreds patients (84% male and 16% female were included with a mean age of (37.9±13.7 years. Chin J Traumatol 2013;16(6:351-354 Rib fracture was the most common finding of CXR (12.5% and CT scan (25.5%. The sensitivity of CXR for hemothorax, thoracolumbar vertebra fractures and rib fractures were 20%, 49% and 49%, respectively. Pneumothorax, foreign body, emphysema, pulmonary contusion, liver hematoma and ster- num fracture were not diagnosed with CXR alone. Conclusion: Applying CT scan as the first-line diag- nostic modality in hemodynamically stable patients with blunt chest trauma can detect pathologies which may change management and outcome. Key words: Radiography; Thoracic injuries; Tomography, X-ray computed

The methods for detecting multiple small nodules from 3D chest X-ray CT images

International Nuclear Information System (INIS)

Hayase, Yosuke; Mekada, Yoshito; Mori, Kensaku; Toriwaki, Jun-ichiro; Natori, Hiroshi

2004-01-01

This paper describes a method for detecting small nodules, whose CT values and diameters are more than -600 Hounsfield unit (H.U.) and 2 mm, from three-dimensional chest X-ray CT images. The proposed method roughly consists of two submodules: initial detection of nodule candidates by discriminating between nodule regions and other regions such as blood vessels or bronchi using a shape feature computed from distance values inside the regions and reduction of false positive (FP) regions by using a minimum directional difference filter called minimum directional difference filter (Min-DD) changing its radius suit to the size of the initial candidates. The performance of the proposed method was evaluated by using seven cases of chest X-ray CT images including six abnormal cases where multiple lung cancers are observed. The experimental results for nodules (361 regions in total) showed that sensitivity and FP regions are 71% and 7.4 regions in average per case. (author)

Detection of skeletal muscle metastasis: torso FDG PET-CT versus contrast-enhanced chest or abdomen CT.

Science.gov (United States)

So, Young; Yi, Jeong Geun; Song, Inyoung; Lee, Won Woo; Chung, Hyun Woo; Park, Jeong Hee; Moon, Sung Gyu

2015-07-01

Skeletal muscle metastasis (SMM) in cancer patients has not been sufficiently evaluated regarding prevalence and proper method of detection. To determine the prevalence of SMM and compare the diagnostic competencies for SMM of torso F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) and contrast-enhanced chest or abdomen CT. We investigated 18,225 PET-CT studies of 6359 cancer patients performed from 2005 to 2012. The PET-CT studies describing potential SMM were retrieved and the corresponding medical records were reviewed. The gold standard for SMM was histopathologically-proven SMM or imaging study-based disease progression. The detectability of SMM was compared between PET-CT and contrast-enhanced CT. Twenty-six patients had 84 SMM lesions, representing a SMM prevalence of 0.41%. Lung cancer was the most common SMM-associated malignancy (54%) and the gluteal/pelvic girdle muscle was the most frequently involved SMM site (37%). All 84 SMM lesions were visualized on PET-CT (100%). Of these PET-CT positive 84 SMM lesions, 51 lesions were in the CT field of view (FOV) (61%), whereas 33 lesions were out of the CT FOV (39%). Among these 51 lesions, 17 lesions showed rim-enhancing nodules/masses (33%), eight lesions showed homogeneously enhancing nodules (16%), three lesions showed heterogeneously enhancing nodules (6%), and 23 SMM lesions (45%) were non-diagnostic by CT. All 51 SMM lesions within CT FOV were detected on PET-CT (100%), whereas only 28 were visualized on CT (54.9%), resulting in a significant difference (P SMM was revealed by PET-CT. The prevalence of SMM was as low as 0.41% in the current large cohort of cancer patients. Torso PET-CT was a more competent modality than contrast-enhanced CT in the detection of SMM. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Overview of two years of clinical experience of chest tomo-synthesis at Sahlgrenska university hospital

International Nuclear Information System (INIS)

Johnsson, Aa. A.; Vikgren, J.; Svalkvist, A.; Zachrisson, S.; Flinck, A.; Boijsen, M.; Kheddache, S.; Maansson, L. G.; Baath, M.

2010-01-01

Since December 2006, ∼ 3800 clinical chest tomo-synthesis examinations have been performed at our department at Sahlgrenska Univ. Hospital. A subset of the examinations has been included in studies of the detectability of pulmonary nodules, using computed tomography (CT) as the gold standard. Visibility studies, in which chest tomo-synthesis and CT have been compared side-by side, have been used to determine the depiction potential of chest tomo-synthesis. Comparisons with conventional chest radiography have been made. In the clinical setting, chest tomo-synthesis has mostly been used as an additional examination. The most frequent indication for chest tomo-synthesis has been suspicion of a nodule or tumour. In visibility studies, tomo-synthesis has depicted over 90% of the nodules seen on the CT scan. The corresponding figure for chest radiography has been <30%. In the detection studies, the lesion-level sensitivity has been ∼ 60% for tomo-synthesis and 20% for chest radiography. In one of the detection studies, an analysis of all false-positive nodules was performed. This analysis showed that all findings had morphological correlates on the CT examinations. The majority of the false-positive nodules were localised in the immediate sub-pleural region. In conclusion, chest tomo-synthesis is an improved chest radiography method, which can be used to optimise the use of CT resources, thereby reducing the radiation dose to the patient population. However, there are some limitations with chest tomo-synthesis. For example, patients undergoing tomo-synthesis have to be able to stand still and hold their breath firmly for 10 s. Also, chest tomo-synthesis has a limited depth resolution, which may explain why pathology in the sub-pleural region is more difficult to interpret and artefacts from medical devices may occur. (authors)

Computer-Aided Segmentation and Volumetry of Artificial Ground-Glass Nodules at Chest CT

NARCIS (Netherlands)

Scholten, Ernst Th.; Jacobs, Colin; van Ginneken, Bram; Willemink, Martin J.; Kuhnigk, Jan-Martin; van Ooijen, Peter M. A.; Oudkerk, Matthijs; Mali, Willem P. Th. M.; de Jong, Pim A.

OBJECTIVE. The purpose of this study was to investigate a new software program for semiautomatic measurement of the volume and mass of ground-glass nodules (GGNs) in a chest phantom and to investigate the influence of CT scanner, reconstruction filter, tube voltage, and tube current. MATERIALS AND

Three-dimensional automatic computer-aided evaluation of pleural effusions on chest CT images

Science.gov (United States)

Bi, Mark; Summers, Ronald M.; Yao, Jianhua

2011-03-01

The ability to estimate the volume of pleural effusions is desirable as it can provide information about the severity of the condition and the need for thoracentesis. We present here an improved version of an automated program to measure the volume of pleural effusions using regular chest CT images. First, the lungs are segmented using region growing, mathematical morphology, and anatomical knowledge. The visceral and parietal layers of the pleura are then extracted based on anatomical landmarks, curve fitting and active contour models. The liver and compressed tissues are segmented out using thresholding. The pleural space is then fitted to a Bezier surface which is subsequently projected onto the individual two-dimensional slices. Finally, the volume of the pleural effusion is quantified. Our method was tested on 15 chest CT studies and validated against three separate manual tracings. The Dice coefficients were 0.74+/-0.07, 0.74+/-0.08, and 0.75+/-0.07 respectively, comparable to the variation between two different manual tracings.

Radiation dose reduction in CT with adaptive statistical iterative reconstruction (ASIR) for patients with bronchial carcinoma and intrapulmonary metastases

International Nuclear Information System (INIS)

Schäfer, M.-L.; Lüdemann, L.; Böning, G.; Kahn, J.; Fuchs, S.; Hamm, B.; Streitparth, F.

2016-01-01

Aim: To compare the radiation dose and image quality of 64-row chest computed tomography (CT) in patients with bronchial carcinoma or intrapulmonary metastases using full-dose CT reconstructed with filtered back projection (FBP) at baseline and reduced dose with 40% adaptive statistical iterative reconstruction (ASIR) at follow-up. Materials and methods: The chest CT images of patients who underwent FBP and ASIR studies were reviewed. Dose–length products (DLP), effective dose, and size-specific dose estimates (SSDEs) were obtained. Image quality was analysed quantitatively by signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurement. In addition, image quality was assessed by two blinded radiologists evaluating images for noise, contrast, artefacts, visibility of small structures, and diagnostic acceptability using a five-point scale. Results: The ASIR studies showed 36% reduction in effective dose compared with the FBP studies. The qualitative and quantitative image quality was good to excellent in both protocols, without significant differences. There were also no significant differences for SNR except for the SNR of lung surrounding the tumour (FBP: 35±17, ASIR: 39±22). Discussion: A protocol with 40% ASIR can provide approximately 36% dose reduction in chest CT of patients with bronchial carcinoma or intrapulmonary metastases while maintaining excellent image quality. - Highlights: • adaptive statistical iterative reconstruction in chest computed tomography scans. • patients with bronchial carcinoma or intrapulmonary metastases. • ASIR studies showed 36% reduction in effective dose compared with the FBP studies. • the qualitative and quantitative image quality was good to excellent in both protocols.

Radiation dose reduction in CT with adaptive statistical iterative reconstruction (ASIR) for patients with bronchial carcinoma and intrapulmonary metastases.

Science.gov (United States)

Schäfer, M-L; Lüdemann, L; Böning, G; Kahn, J; Fuchs, S; Hamm, B; Streitparth, F

2016-05-01

To compare the radiation dose and image quality of 64-row chest computed tomography (CT) in patients with bronchial carcinoma or intrapulmonary metastases using full-dose CT reconstructed with filtered back projection (FBP) at baseline and reduced dose with 40% adaptive statistical iterative reconstruction (ASIR) at follow-up. The chest CT images of patients who underwent FBP and ASIR studies were reviewed. Dose-length products (DLP), effective dose, and size-specific dose estimates (SSDEs) were obtained. Image quality was analysed quantitatively by signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurement. In addition, image quality was assessed by two blinded radiologists evaluating images for noise, contrast, artefacts, visibility of small structures, and diagnostic acceptability using a five-point scale. The ASIR studies showed 36% reduction in effective dose compared with the FBP studies. The qualitative and quantitative image quality was good to excellent in both protocols, without significant differences. There were also no significant differences for SNR except for the SNR of lung surrounding the tumour (FBP: 35±17, ASIR: 39±22). A protocol with 40% ASIR can provide approximately 36% dose reduction in chest CT of patients with bronchial carcinoma or intrapulmonary metastases while maintaining excellent image quality. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Breast Cancer After Chest Radiation Therapy for Childhood Cancer

Science.gov (United States)

Moskowitz, Chaya S.; Chou, Joanne F.; Wolden, Suzanne L.; Bernstein, Jonine L.; Malhotra, Jyoti; Friedman, Danielle Novetsky; Mubdi, Nidha Z.; Leisenring, Wendy M.; Stovall, Marilyn; Hammond, Sue; Smith, Susan A.; Henderson, Tara O.; Boice, John D.; Hudson, Melissa M.; Diller, Lisa R.; Bhatia, Smita; Kenney, Lisa B.; Neglia, Joseph P.; Begg, Colin B.; Robison, Leslie L.; Oeffinger, Kevin C.

2014-01-01

Purpose The risk of breast cancer is high in women treated for a childhood cancer with chest irradiation. We sought to examine variations in risk resulting from irradiation field and radiation dose. Patients and Methods We evaluated cumulative breast cancer risk in 1,230 female childhood cancer survivors treated with chest irradiation who were participants in the CCSS (Childhood Cancer Survivor Study). Results Childhood cancer survivors treated with lower delivered doses of radiation (median, 14 Gy; range, 2 to 20 Gy) to a large volume (whole-lung field) had a high risk of breast cancer (standardized incidence ratio [SIR], 43.6; 95% CI, 27.2 to 70.3), as did survivors treated with high doses of delivered radiation (median, 40 Gy) to the mantle field (SIR, 24.2; 95% CI, 20.7 to 28.3). The cumulative incidence of breast cancer by age 50 years was 30% (95% CI, 25 to 34), with a 35% incidence among Hodgkin lymphoma survivors (95% CI, 29 to 40). Breast cancer–specific mortality at 5 and 10 years was 12% (95% CI, 8 to 18) and 19% (95% CI, 13 to 25), respectively. Conclusion Among women treated for childhood cancer with chest radiation therapy, those treated with whole-lung irradiation have a greater risk of breast cancer than previously recognized, demonstrating the importance of radiation volume. Importantly, mortality associated with breast cancer after childhood cancer is substantial. PMID:24752044

Comparison between plain chest film and CT in estimating the size of pneumothorax

International Nuclear Information System (INIS)

Seto, Yuichi

1995-01-01

Regarding the patients diagnosed as having traumatic and spontaneous pneumothorax at our emergency center within the past 6 years we examined the distribution of pneumothorax shown by plain chest film and CT, and compared the pneumothorax rate evaluated by Kircher's method with plain chest film and that by one slice method with CT, which was based on full slice integration method with CT. Occult pneumothorax was found in 47.6% of traumatic cases and 11.1% of spontaneous cases. The distribution of pneumothoraces showed no significant differences. However, as compared with classical pneumothorax, the ratio of pneumothoraces in the apicolateral recess in the occult pneumothoraces tended to be lower, whereas the ratio of the ones in the anteromedial recess and in the subpulmonic recess tended to be comparatively high. The plain chest film of occult pneumothorax had been taken on supine position in most cases of traumatic pneumothorax and in more than half the cases of spontaneous pneumothorax. This was considered to be the cause of the unique distribution of pneumothorax. The pneumothorax rate evaluated by Kircher's method tended to be underestimated in comparison with the basic rate, where the correlation coefficient was R=0.84 for traumatic pneumothorax and R=0.14 for spontaneous pneumothorax. Especially in the cases of low pneumothorax rate the correlation was poor. The pneumothorax rate calculated by one slice method produced better figures with the correlation coefficient of R=0.92 for traumatic pneumothorax and R=0.85 for spontaneous pneumothorax. The one slice method was considered to be effective in evaluation of the degree of serious cases, and also for the choice of treatment modality for pneumothorax. (author)

Changes of intrathoracic extrapulmonary organs after radiation therapy for lung and esophageal cancer:CT findings

International Nuclear Information System (INIS)

Song, Kyeong Seop; Kim, Sung Jin; Park, Woo Yoon; Hun, Bae Il; Han, Gi Seok; Cha, Sang Hun; Park, Kil Sun

2001-01-01

To evaluate the CT findings and incidence of complications occurring in intrathoracic extrapulmonary organs due to radiation therapy. Among 82 patients who underwent chest CT before and after radiation therapy, 23, in whom the procedure provided no evidence of pericardial invasion or pleural effusion before radiation therapy, nor of significant improvement in the tumor after this therapy, were evaulated. Changes in the pericardium, pleura and mediastinal fat were retrospectively assessed. In comparing the CT findings obtained before radiation therapy with those obtained afterwards, changes in the pericardium and pleura were classified as effusion where low density fluid was present and as thickening where there was no fluid. If an increased abundance of soft tissue strands was seen within mediastinal fat, changes in this fat were deemed to have occurred. Among the 23 patients evaluated, changes in the pericardium [thickening (n=3 ; 13.0%) ; effusion (n=8 ; 34.8%)] were found in 11 patients (47.8%), and changes in the pleura [thickening (n=3 ; 13.1%); effusion (n=9 ; 39.1%)] in 12 (52.2%). In no patient with pericardial or pleural effusion was thickening or contrast enhancement of the pericardium or pleura evident. In seven cases(30.4%), soft tissue strands within mediastinal fat had become more abundant. The CT findings which demonstrated complications resulting from radiation therapy were pericardial or pleural thickening or effusion and an increased abundance of soft tissue strands within mediastinal fat. In contrast to previous reports, pericardial and pleural change after radiation therapy was a common finding in our study, occurring in 69.6% of cases

Coronary artery visibility in free-breathing young children on non-gated chest CT: impact of temporal resolution

Energy Technology Data Exchange (ETDEWEB)

Bridoux, Alexandre; Hutt, Antoine; Faivre, Jean-Baptiste; Pagniez, Julien; Remy, Jacques; Remy-Jardin, Martine [CHRU et Universite de Lille, Department of Thoracic Imaging, Hospital Calmette (EA 2694), 59037 Lille Cedex (France); Flohr, Thomas [Siemens Healthcare, Department of Research and Development in CT, Forchheim (Germany); Duhamel, Alain [Universite de Lille, Department of Biostatistics, Lille (France)

2015-11-15

Dual-source CT allows scanning of the chest with high pitch and high temporal resolution, which can improve the detection of proximal coronary arteries in infants and young children when scanned without general anesthesia, sedation or beta-blockade. To compare coronary artery visibility between higher and standard temporal resolution. We analyzed CT images in 93 children who underwent a standard chest CT angiographic examination with reconstruction of images with a temporal resolution of 75 ms (group 1) and 140 ms (group 2). The percentage of detected coronary segments was higher in group 1 than in group 2 when considering all segments (group 1: 27%; group 2: 24%; P = 0.0004) and proximal segments (group 1: 37%; group 2: 32%; P = 0.0006). In both groups, the highest rates of detection were observed for the left main coronary artery (S1) (group 1: 65%; group 2: 58%) and proximal left anterior descending coronary artery (S2) (group 1: 43%; group 2: 42%). Higher rates of detection were seen in group 1 for the left main coronary artery (P = 0.03), proximal right coronary artery (P = 0.01), proximal segments of the left coronary artery (P = 0.02) and proximal segments of the left and right coronary arteries (P = 0.0006). Higher temporal resolution improved the visibility of proximal coronary arteries in pediatric chest CT. (orig.)

Cardiovascular disease prediction: do pulmonary disease-related chest CT features have added value?

International Nuclear Information System (INIS)

Jairam, Pushpa M.; Jong, Pim A. de; Mali, Willem P.T.M.; Isgum, Ivana; Graaf, Yolanda van der

2015-01-01

Certain pulmonary diseases are associated with cardiovascular disease (CVD). Therefore we investigated the incremental predictive value of pulmonary, mediastinal and pleural features over cardiovascular imaging findings. A total of 10,410 patients underwent diagnostic chest CT for non-cardiovascular indications. Using a case-cohort approach, we visually graded CTs from the cases and from an approximately 10 % random sample of the baseline cohort (n = 1,203) for cardiovascular, pulmonary, mediastinal and pleural findings. The incremental value of pulmonary disease-related CT findings above cardiovascular imaging findings in cardiovascular event risk prediction was quantified by comparing discrimination and reclassification. During a mean follow-up of 3.7 years (max. 7.0 years), 1,148 CVD events (cases) were identified. Addition of pulmonary, mediastinal and pleural features to a cardiovascular imaging findings-based prediction model led to marginal improvement of discrimination (increase in c-index from 0.72 (95 % CI 0.71-0.74) to 0.74 (95 % CI 0.72-0.75)) and reclassification measures (net reclassification index 6.5 % (p < 0.01)). Pulmonary, mediastinal and pleural features have limited predictive value in the identification of subjects at high risk of CVD events beyond cardiovascular findings on diagnostic chest CT scans. (orig.)

Cardiovascular disease prediction: do pulmonary disease-related chest CT features have added value?

Energy Technology Data Exchange (ETDEWEB)

Jairam, Pushpa M. [University Medical Center Utrecht, Julius Center for Health Sciences and Primary Care, Utrecht (Netherlands); University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Jong, Pim A. de; Mali, Willem P.T.M. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Isgum, Ivana [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands); Graaf, Yolanda van der [University Medical Center Utrecht, Julius Center for Health Sciences and Primary Care, Utrecht (Netherlands); Collaboration: PROVIDI study-group

2015-06-01

Certain pulmonary diseases are associated with cardiovascular disease (CVD). Therefore we investigated the incremental predictive value of pulmonary, mediastinal and pleural features over cardiovascular imaging findings. A total of 10,410 patients underwent diagnostic chest CT for non-cardiovascular indications. Using a case-cohort approach, we visually graded CTs from the cases and from an approximately 10 % random sample of the baseline cohort (n = 1,203) for cardiovascular, pulmonary, mediastinal and pleural findings. The incremental value of pulmonary disease-related CT findings above cardiovascular imaging findings in cardiovascular event risk prediction was quantified by comparing discrimination and reclassification. During a mean follow-up of 3.7 years (max. 7.0 years), 1,148 CVD events (cases) were identified. Addition of pulmonary, mediastinal and pleural features to a cardiovascular imaging findings-based prediction model led to marginal improvement of discrimination (increase in c-index from 0.72 (95 % CI 0.71-0.74) to 0.74 (95 % CI 0.72-0.75)) and reclassification measures (net reclassification index 6.5 % (p < 0.01)). Pulmonary, mediastinal and pleural features have limited predictive value in the identification of subjects at high risk of CVD events beyond cardiovascular findings on diagnostic chest CT scans. (orig.)

Reporting of coronary artery calcification on chest CT studies in breast cancer patients at high risk of cancer therapy related cardiac events

Directory of Open Access Journals (Sweden)

William J. Phillips

2018-03-01

Full Text Available Background: The identification of coronary artery calcification (CAC detected coincidentally on chest CT exams could assist in cardiovascular risk assessment but may not be reported consistently on clinical studies. Cardiovascular risk factor stratification is important to predict short term cardiac events during cancer therapy and long term cardiac event free survival in cancer patients. We sought to determine the prevalence of CAC and clinical reporting rates in a cohort of cancer patients at high risk of cancer therapy related cardiac events. Methods: 408 Breast cancer patients who were referred to a cardiac oncology clinic were screened. Inclusion criteria included having had a CT chest and the absence of known coronary disease. Among those screened 263 patients were included in the study. Results: CAC was identified in 70 patients (26%. CAC was reported in 18% of studies. The reporting rates of CAC increased with the extent of coronary calcification (p < 0.01 and increased during the period of the study (p < 0.05. Conclusions: CAC was commonly detected on chest CT studies in this observational study of breast cancer patients at high risk of cardiac oncology events. The presence of CAC was often not reported clinically but reporting rates have increased over time. Recent SCCT/STR guidelines recommend reporting the presence of CAC on routine chest CT scans in recognition of the importance of CAC as a predictor of cardiovascular events. Reporting of CAC on chest CTs may help to further risk stratify breast cancer patients and improve cardiovascular outcomes in this vulnerable population. Keywords: Cardiac oncology, Coronary calcification and chest CT

Radiation exposure in CT-guided interventions

Energy Technology Data Exchange (ETDEWEB)

Kloeckner, Roman, E-mail: Roman.Kloeckner@unimedizin-mainz.de [Department of Diagnostic and Interventional Radiology, Johannes Gutenberg-University, Langenbeckstraße 1, 55131 Mainz (Germany); Santos, Daniel Pinto dos; Schneider, Jens [Department of Diagnostic and Interventional Radiology, Johannes Gutenberg-University, Langenbeckstraße 1, 55131 Mainz (Germany); Kara, Levent [Department of Radiology, Inselspital Bern, Freiburgstraße 18, 3010 Bern (Switzerland); Dueber, Christoph; Pitton, Michael B. [Department of Diagnostic and Interventional Radiology, Johannes Gutenberg-University, Langenbeckstraße 1, 55131 Mainz (Germany)

2013-12-01

Purpose: To investigate radiation exposure in computed tomography (CT)-guided interventions, to establish reference levels for exposure, and to discuss strategies for dose reduction. Materials and methods: We analyzed 1576 consecutive CT-guided procedures in 1284 patients performed over 4.5 years, including drainage placements; biopsies of different organs; radiofrequency and microwave ablations (RFA/MWA) of liver, bone, and lung tumors; pain blockages, and vertebroplasties. Data were analyzed with respect to scanner settings, overall radiation doses, and individual doses of planning CT series, CT intervention, and control CT series. Results: Eighy-five percent of the total radiation dose was applied during the pre- and post-interventional CT series, leaving only 15% applied by the CT-guided intervention itself. Single slice acquisition was associated with lower doses than continuous CT-fluoroscopy (37 mGy cm vs. 153 mGy cm, p < 0.001). The third quartile of radiation doses varied considerably for different interventions. The highest doses were observed in complex interventions like RFA/MWA of the liver, followed by vertebroplasty and RFA/MWA of the lung. Conclusions: This paper suggests preliminary reference levels for various intervention types and discusses strategies for dose reduction. A multicenter registry of radiation exposure including a broader spectrum of scanners and intervention types is needed to develop definitive reference levels.

Children's (Pediatric) CT (Computed Tomography)

Medline Plus

Full Text Available ... CT of the chest is used to evaluate: complications from infections such as pneumonia a tumor that ... radiation dose. There always is a risk of complications from general anesthesia or sedation. Every measure will ...

Optimal dose levels in screening chest CT for unimpaired detection and volumetry of lung nodules, with and without computer assisted detection at minimal patient radiation.

Directory of Open Access Journals (Sweden)

Andreas Christe

Full Text Available OBJECTIVES: The aim of this phantom study was to minimize the radiation dose by finding the best combination of low tube current and low voltage that would result in accurate volume measurements when compared to standard CT imaging without significantly decreasing the sensitivity of detecting lung nodules both with and without the assistance of CAD. METHODS: An anthropomorphic chest phantom containing artificial solid and ground glass nodules (GGNs, 5-12 mm was examined with a 64-row multi-detector CT scanner with three tube currents of 100, 50 and 25 mAs in combination with three tube voltages of 120, 100 and 80 kVp. This resulted in eight different protocols that were then compared to standard CT sensitivity (100 mAs/120 kVp. For each protocol, at least 127 different nodules were scanned in 21-25 phantoms. The nodules were analyzed in two separate sessions by three independent, blinded radiologists and computer-aided detection (CAD software. RESULTS: The mean sensitivity of the radiologists for identifying solid lung nodules on a standard CT was 89.7% ± 4.9%. The sensitivity was not significantly impaired when the tube and current voltage were lowered at the same time, except at the lowest exposure level of 25 mAs/80 kVp [80.6% ± 4.3% (p = 0.031]. Compared to the standard CT, the sensitivity for detecting GGNs was significantly lower at all dose levels when the voltage was 80 kVp; this result was independent of the tube current. The CAD significantly increased the radiologists' sensitivity for detecting solid nodules at all dose levels (5-11%. No significant volume measurement errors (VMEs were documented for the radiologists or the CAD software at any dose level. CONCLUSIONS: Our results suggest a CT protocol with 25 mAs and 100 kVp is optimal for detecting solid and ground glass nodules in lung cancer screening. The use of CAD software is highly recommended at all dose levels.

Characterization of the relation between CT technical parameters and accuracy of quantification of lung attenuation on quantitative chest CT.

Science.gov (United States)

Trotta, Brian M; Stolin, Alexander V; Williams, Mark B; Gay, Spencer B; Brody, Alan S; Altes, Talissa A

2007-06-01

The purpose of this study was to assess the compromise between CT technical parameters and the accuracy of CT quantification of lung attenuation. Materials that simulate water (0 H), healthy lung (-650 H), borderline emphysematous lung (-820 H), and severely emphysematous lung (-1,000 H) were placed at both the base and the apex of the lung of an anthropomorphic phantom and outside the phantom. Transaxial CT images through the samples were obtained while the effective tube current was varied from 440 to 10 mAs, kilovoltage from 140 to 80 kVp, and slice thickness from 0.625 to 10 mm. Mean +/- SD attenuation within the samples and the standard quantitative chest CT measurements, the percentage of pixels with attenuation less than -910 H and 15th percentile of attenuation, were computed. Outside the phantom, variations in CT parameters produced less than 2.0% error in all measurements. Within the anthropomorphic phantom at 30 mAs, error in measurements was much larger, ranging from zero to 200%. Below approximately 80 mAs, mean attenuation became increasingly biased. The effects were most pronounced at the apex of the lungs. Mean attenuation of the borderline emphysematous sample of apex decreased 55 H as the tube current was decreased from 300 to 30 mAs. Both the 15th percentile of attenuation and percentage of pixels with less than -910 H attenuation were more sensitive to variations in effective tube current than was mean attenuation. For example, the -820 H sample should have 0% of pixels less than -910 H, which was true at 400 mA. At 30 mA in the lung apex, however, the measurement was highly inaccurate, 51% of pixels being below this value. Decreased kilovoltage and slice thickness had analogous, but lesser, effects. The accuracy of quantitative chest CT is determined by the CT acquisition parameters. There can be significant decreases in accuracy at less than 80 mAs for thin slices in an anthropomorphic phantom, the most pronounced effects occurring in the lung

Limiting chest computed tomography in the evaluation of pediatric thoracic trauma.

Science.gov (United States)

Golden, Jamie; Isani, Mubina; Bowling, Jordan; Zagory, Jessica; Goodhue, Catherine J; Burke, Rita V; Upperman, Jeffrey S; Gayer, Christopher P

2016-08-01

Computed tomography (CT) of the chest (chest CT) is overused in blunt pediatric thoracic trauma. Chest CT adds to the diagnosis of thoracic injury but rarely changes patient management. We sought to identify a subset of blunt pediatric trauma patients who would benefit from a screening chest CT based on their admission chest x-ray (CXR) findings. We hypothesize that limiting chest CT to patients with an abnormal mediastinal silhouette identifies intrathoracic vascular injuries not otherwise seen on CXR. All blunt trauma activations that underwent an admission CXR at our Level 1 pediatric trauma center from 2005 to 2013 were retrospectively reviewed. Patients who had a chest CT were evaluated for added diagnoses and change in management after CT. An admission CXR was performed in 1,035 patients. One hundred thirty-nine patients had a CT, and the diagnosis of intra-thoracic injury was added in 42% of patients. Chest CT significantly increased the diagnosis of contusion or atelectasis (30.3% vs 60.4%; p pneumothorax (7.2% vs 18.7%; p chest CT. Chest CT changed the management of only 4 patients (2.9%). Two patients underwent further radiologic evaluation that was negative for injury, one had a chest tube placed for an occult pneumothorax before exploratory laparotomy, and one patient had a thoracotomy for repair of aortic injury. Chest CT for select patients with an abnormal mediastinal silhouette on CXR would have decreased CT scans by 80% yet still identified patients with an intrathoracic vascular injury. The use of chest CT should be limited to the identification of intrathoracic vascular injuries in the setting of an abnormal mediastinal silhouette on CXR. Therapeutic study, level IV; diagnostic study, level III.

Influence of chest radiotherapy in frequency and patterns of chest relapse in disseminated small cell lung carcinoma

International Nuclear Information System (INIS)

Mira, J.G.; Livingston, R.B.; Moore, T.N.

1982-01-01

The value of radiotherapy to the chest (RC) in disseminated small cell lung carcinoma (SCLC) has been questioned. Two protocols for disseminated SCLC from the Southwest Oncology Group (SWOG) have been compared. The first one included radiotherapy (RT), 3000 rad in two weeks, to the primary tumor, mediastinum and supraclavicular areas, while the second one deleted any RC. Multidrug chemotherapy (CT) and brain RT were used in both protocols. Nonresponders to CT were removed from the study. Our main findings are as follows: (1) Initial chest relapses (patients with no initial extrathoracic relapse) have increased from 24-55% when RC is not given (P = 0.0001). Overall chest relapse (adding those patients that relapsed simultaneously in the chest plus other sites) in the second protocol was 73%. (2) Amount of response to CT does not influence the chances for relapse. Even complete responders to CT have a high chance for chest relapse. (3) Sites of relapse without RC are mainly in the primary tumor, ipsilateral hilus and mediastinum. (4) With RC, relapses shift to the chest periphery, mostly to the lung outside the radiotherapy field and to the pleura. (5) The two very different CT regimens have produced similar percentages and duration of response. (6) CT schema with periodic reinductions prolongs duration of response and survival over schema with continuous maintenance. Hence, interruption of CT to allow RC does not seem to adversely influence CT efficacy

Radiodiagnostic measurements radiation load of children by chest

International Nuclear Information System (INIS)

Nikodemova, D.; Vladar, M.; Ranogajec, M.; Horvathova, M

1998-01-01

In the district of Slovak Republic we have tried to estimate the radiation load of children to 15 years by chest radiodiagnostic examinations. Our data were collected using measurements with TLD for 100 patients divided in 5 age categories at six radiodiagnostic departments. The analysis of obtained absorbed doses as a function of age for chest radiodiagnostic examinations has shown, that the investigated Slovak radiodiagnostic centres use rather lower voltage techniques and the entrance surface doses are much higher than the proposed value of European Communities. (authors)

Comparison of radiation dose estimates, image noise, and scan duration in pediatric body imaging for volumetric and helical modes on 320-detector CT and helical mode on 64-detector CT

International Nuclear Information System (INIS)

Johnston, Jennifer H.; Podberesky, Daniel J.; Larson, David B.; Alsip, Christopher; Yoshizumi, Terry T.; Angel, Erin; Barelli, Alessandra; Toncheva, Greta; Egelhoff, John C.; Anderson-Evans, Colin; Nguyen, Giao B.; Frush, Donald P.; Salisbury, Shelia R.

2013-01-01

Advanced multidetector CT systems facilitate volumetric image acquisition, which offers theoretic dose savings over helical acquisition with shorter scan times. Compare effective dose (ED), scan duration and image noise using 320- and 64-detector CT scanners in various acquisition modes for clinical chest, abdomen and pelvis protocols. ED and scan durations were determined for 64-detector helical, 160-detector helical and volume modes under chest, abdomen and pelvis protocols on 320-detector CT with adaptive collimation and 64-detector helical mode on 64-detector CT without adaptive collimation in a phantom representing a 5-year-old child. Noise was measured as standard deviation of Hounsfield units. Compared to 64-detector helical CT, all acquisition modes on 320-detector CT resulted in lower ED and scan durations. Dose savings were greater for chest (27-46%) than abdomen/pelvis (18-28%) and chest/abdomen/pelvis imaging (8-14%). Noise was similar across scanning modes, although some protocols on 320-detector CT produced slightly higher noise. Dose savings can be achieved for chest, abdomen/pelvis and chest/abdomen/pelvis examinations on 320-detector CT compared to helical acquisition on 64-detector CT, with shorter scan durations. Although noise differences between some modes reached statistical significance, this is of doubtful diagnostic significance and will be studied further in a clinical setting. (orig.)

Practical applications of digital tomosynthesis of the chest.

Science.gov (United States)

Galea, A; Durran, A; Adlan, T; Gay, D; Riordan, R; Dubbins, P; Williams, M P

2014-04-01

Digital tomosynthesis is a radiographic technique that generates a number of coronal raw images of a patient from a single pass of the x-ray tube. Tomosynthesis provides some of the tomographic benefits of computed tomography (CT), but at a much lower dose of radiation and cost when compared to CT. This review illustrates the range of practical applications of digital tomosynthesis of the chest. Copyright © 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Prevalence and Severity of Off-Centering During Diagnostic CT: Observations From 57,621 CT scans of the Chest, Abdomen, and/or Pelvis.

Science.gov (United States)

Akin-Akintayo, Oladunni O; Alexander, Lauren F; Neill, Rebecca; Krupinksi, Elizabeth A; Tang, Xiangyang; Mittal, Pardeep K; Small, William C; Moreno, Courtney C

2018-02-23

To determine distances between patient centroid and gantry isocenter during CT imaging of the chest, abdomen, and/or pelvis, and to evaluate differences based on patient gender, scan region, patient position, and gantry aperture. A water phantom and an anthropomorphic phantom were imaged in the centered position in the CT gantry and at several off-centered positions. Additionally, data from 57,621 adult chest, abdomen, and/or pelvic CT acquisitions were evaluated. Data were analyzed with an analysis of variance using the centroid-to-isocenter data as the dependent variable and the other parameters as independent variables. The majority of patient acquisitions (83.7% (48271/57621)) were performed with the patient's centroid positioned below isocenter (mean 1.7 cm below isocenter (SD 1.8 cm); range 12.1 cm below to 7.8 cm above isocenter). Off-centering in the x-axis was less severe (mean 0.01 cm left of isocenter (SD 1.6 cm)). Distance between centroid and isocenter in the y-axis did not differ as a function of sex but did differ based on scan region, patient position, and gantry aperture. Off-centering is common during CT imaging and has been previously demonstrated to impact dose and image quality. Copyright © 2018 Elsevier Inc. All rights reserved.

Gonad protective effect of radiation protective apron in chest radiography

International Nuclear Information System (INIS)

Hashimoto, Masatoshi; Kato, Hideyuki; Fujibuchi, Toshiou; Ochi, Shigehiro; Morita, Fuminori

2004-01-01

Depending on the facility, a radiation protective apron (protector) is used to protect the gonad from radiation exposure in chest radiography. To determine the necessity of using a protector during chest radiography, we measured the effect of the protector on the gonad in this study. First, using a human body phantom, we measured the absorbed dose of the female gonad with and without the protector, using a thermoluminescence dosimeter (TLD), and confirmed its protective effect. Using the protector, the absorbed dose was reduced to 28±2% and 39±4% for field sizes of 14 x 17 inch and 14 x 14 inch, respectively. Next, we used Monte Carlo simulation and confirmed, not only the validity of the actual measurement values, but also the fact that the influence of radiation on the absorbed dose of the gonad was mostly from scattered radiation from inside the body for the 14 x 17 inch field size, and also from the X-ray tube for the 14 x 14 inch field size. Although a certain protective effect is achieved by using the protector, the radiation dose to the gonad is only a few μGy even without a protector. Thus, the risk of a genetic effect would be as small as 10 -8 . Given that acceptable risk is below 10 -6 , we conclude the use of a radiation protective apron is not necessary for diagnostic chest radiography. (author)

[Gonad protective effect of radiation protective apron in chest radiography].

Science.gov (United States)

Hashimoto, Masatoshi; Kato, Hideyuki; Fujibuchi, Toshiou; Ochi, Shigehiro; Morita, Fuminori

2004-12-01

Depending on the facility, a radiation protective apron (protector) is used to protect the gonad from radiation exposure in chest radiography. To determine the necessity of using a protector during chest radiography, we measured the effect of the protector on the gonad in this study. First, using a human body phantom, we measured the absorbed dose of the female gonad with and without the protector, using a thermoluminescence dosimeter (TLD), and confirmed its protective effect. Using the protector, the absorbed dose was reduced to 28+/-2% and 39+/-4% for field sizes of 14 x 17 inch and 14 x 14 inch, respectively. Next, we used Monte Carlo simulation and confirmed, not only the validity of the actual measurement values, but also the fact that the influence of radiation on the absorbed dose of the gonad was mostly from scattered radiation from inside the body for the 14 x 17 inch field size, and also from the X-ray tube for the 14 x 14 inch field size. Although a certain protective effect is achieved by using the protector, the radiation dose to the gonad is only a few microGy even without a protector. Thus, the risk of a genetic effect would be as small as 10(-8). Given that acceptable risk is below 10(-6), we conclude the use of a radiation protective apron is not necessary for diagnostic chest radiography.

Chest CT findings in patients with dysphagia and aspiration: a systematic review

International Nuclear Information System (INIS)

Scheeren, Betina; Hochhegger, Bruno; Gomes, Erissandra; Alves, Giordano; Marchiori, Edson

2017-01-01

The objective of this systematic review was to characterize chest CT findings in patients with dysphagia and pulmonary aspiration, identifying the characteristics and the methods used. The studies were selected from among those indexed in the Brazilian Virtual Library of Health, LILACS, Indice Bibliografico Espanol de Ciencias de la Salud, Medline, Cochrane Library, SciELO, and PubMed databases. The search was carried out between June and July of 2016. Five articles were included and reviewed, all of them carried out in the last five years, published in English, and coming from different countries. The sample size in the selected studies ranged from 43 to 56 patients, with a predominance of adult and elderly subjects. The tomographic findings in patients with dysphagia-related aspiration were varied, including bronchiectasis, bronchial wall thickening, pulmonary nodules, consolidations, pleural effusion, ground-glass attenuation, atelectasis, septal thickening, fibrosis, and air trapping. Evidence suggests that chest CT findings in patients with aspiration are diverse. In this review, it was not possible to establish a consensus that could characterize a pattern of pulmonary aspiration in patients with dysphagia, further studies of the topic being needed. (author)

Chest CT findings in patients with dysphagia and aspiration: a systematic review

Energy Technology Data Exchange (ETDEWEB)

Scheeren, Betina; Hochhegger, Bruno, E-mail: betinascheeren@hotmail.com [Universidade Federal de Ciencias da Saude de Porto Alegre (UFCSPA), RS (Brazil); Gomes, Erissandra [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre (Brazil); Alves, Giordano; Marchiori, Edson [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)

2017-07-15

The objective of this systematic review was to characterize chest CT findings in patients with dysphagia and pulmonary aspiration, identifying the characteristics and the methods used. The studies were selected from among those indexed in the Brazilian Virtual Library of Health, LILACS, Indice Bibliografico Espanol de Ciencias de la Salud, Medline, Cochrane Library, SciELO, and PubMed databases. The search was carried out between June and July of 2016. Five articles were included and reviewed, all of them carried out in the last five years, published in English, and coming from different countries. The sample size in the selected studies ranged from 43 to 56 patients, with a predominance of adult and elderly subjects. The tomographic findings in patients with dysphagia-related aspiration were varied, including bronchiectasis, bronchial wall thickening, pulmonary nodules, consolidations, pleural effusion, ground-glass attenuation, atelectasis, septal thickening, fibrosis, and air trapping. Evidence suggests that chest CT findings in patients with aspiration are diverse. In this review, it was not possible to establish a consensus that could characterize a pattern of pulmonary aspiration in patients with dysphagia, further studies of the topic being needed. (author)

Is visual assessment of thyroid attenuation on unenhanced CT of the chest useful for detecting hypothyroidism?

Science.gov (United States)

Maldjian, P D; Chen, T

2016-11-01

To determine if visual assessment of the attenuation of morphologically normal appearing thyroid glands on unenhanced computed tomography (CT) of the chest is useful for identifying patients with decreased thyroid function. This was a retrospective study of 765 patients who underwent both unenhanced CT of the chest and thyroid function tests performed within 1 year of the CT examination. Attenuation of the thyroid gland was visually assessed in each patient relative to the attenuation of the surrounding muscles to categorise the gland as "low attenuation" (attenuation similar to surrounding muscles) or "high attenuation" (attenuation greater than surrounding muscles). Thyroid attenuation was quantitatively measured in each case to determine the validity of the visual assessment. Results of thyroid function tests were used to classify thyroid function as hypothyroid, euthyroid, or hyperthyroid. Data were analysed to determine the relationship between visual assessment of thyroid attenuation and status of thyroid function. Thyroid glands of low attenuation were present in 4.2% (32/765) of the patients. Nearly half (47%) of the patients with low-attenuation thyroids had hypofunctioning thyroid glands. Compared to patients with high-attenuation thyroids, patients with low-attenuation thyroids were significantly more likely to have decreased thyroid function (clinical and subclinical hypothyroidism) and significantly less likely to be euthyroid (p<0.0001). Quantitative measurement of thyroid attenuation confirmed the validity of the visual assessment. Low attenuation of an otherwise normal-appearing thyroid gland on unenhanced CT of the chest is strongly associated with decreased thyroid function. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Evaluating of the relation among emphysematous changes detected by the chest CT, the smoking history and the respiratory function

International Nuclear Information System (INIS)

Hayase, Taichiro; Higuchi, Tomoaki; Iwamoto, Tomohiro

2008-01-01

An influence of smoking on the respiratory function and pulmonary emphysema is well known. However, there are few reports evaluating the relation between smoking and emphysematous changes detected by the chest CT. In this study, we evaluated the relation among emphysematous changes detected by the chest CT, the smoking history and the respiratory function (%VC, FEV 1.0 %). Four hundred and sixty-six healthy members of Self-defense force (mean age; 50.1±5.32 years; all men) were recruited in this study. Emphysematous changes were confirmed by the chest CT in 26 subjects. (5.56%, group A) The remaining 440 subjects showed no emphysematous changes. (group B) On the other hand, 8 subjects (1.7%) were FEV 1.0 % 1.0 % was 76.7±4.7% in group A and 82.5±5.0% in group B (P<0.05). %VC was 117±11.3% in group A and 112±13.2% in group B (P<0.05). In addition, risk to show emphysematous changes in CT was high among the patients whose Brinkmann index (BI) value was over 600 (Odds ratio, 8.2; 95% confidence interval (CI), 3.5 to 18.5). We conducted that it is possible to evaluate the influence of smoking on the respiratory function by the CT as well as respiratory function test. (author)

Pulmonary nodule size evaluation with chest tomosynthesis.

Science.gov (United States)

Johnsson, Åse A; Fagman, Erika; Vikgren, Jenny; Fisichella, Valeria A; Boijsen, Marianne; Flinck, Agneta; Kheddache, Susanne; Svalkvist, Angelica; Båth, Magnus

2012-10-01

To evaluate intra- and interobserver variability, as well as agreement for nodule size measurements on chest tomosynthesis and computed tomographic (CT) images. The Regional Ethical Review Board approved this study, and all participants gave written informed consent. Thirty-six segmented nodules in 20 patients were included in the study. Eight observers measured the left-to-right, inferior-to-superior, and longest nodule diameters on chest tomosynthesis and CT images. Intra- and interobserver repeatability, as well as agreement between measurements on chest tomosynthesis and CT images, were assessed as recommended by Bland and Altman. The difference between the mean manual and the segmented diameter was -2.2 and -2.3 mm for left-to-right and -2.6 and -2.2 mm for the inferior-to-superior diameter for measurements on chest tomosynthesis and CT images, respectively. Intraobserver 95% limits of agreement (LOA) for the longest diameter ranged from a lower limit of -1.1 mm and an upper limit of 1.0 mm to -1.8 and 1.8 mm for chest tomosynthesis and from -0.6 and 0.9 mm to -3.1 and 2.2 mm for axial CT. Interobserver 95% LOA ranged from -1.3 and 1.5 mm to -2.0 and 2.1 mm for chest tomosynthesis and from -1.8 and 1.1 mm to -2.2 and 3.1 mm for axial CT. The 95% LOA concerning the mean of the observers' measurements of the longest diameter at chest tomosynthesis and axial CT were ±2.1 mm (mean measurement error, 0 mm). For the different observers, the 95% LOA between the modalities ranged from -2.2 and 1.6 mm to -3.2 and 2.8 mm. Measurements on chest tomosynthesis and CT images are comparable, because there is no evident bias between the modalities and the repeatability is similar. The LOA between measurements for the two modalities raise concern if measurements from chest tomosynthesis and CT were to be used interchangeably. © RSNA, 2012.

Lung nodule detection in pediatric chest CT: quantitative relationship between image quality and radiologist performance.

Science.gov (United States)

Li, Xiang; Samei, Ehsan; Barnhart, Huiman X; Gaca, Ana Maria; Hollingsworth, Caroline L; Maxfield, Charles M; Carrico, Caroline W T; Colsher, James G; Frush, Donald P

2011-05-01

To determine the quantitative relationship between image quality and radiologist performance in detecting small lung nodules in pediatric CT. The study included clinical chest CT images of 30 pediatric patients (0-16 years) scanned at tube currents of 55-180 mA. Calibrated noise addition software was used to simulate cases at three nominal mA settings: 70, 35, and 17.5 mA, resulting in quantum noise of 7-32 Hounsfield Unit (HU). Using a validated nodule simulation technique, lung nodules with diameters of 3-5 mm and peak contrasts of 200-500 HU were inserted into the cases, which were then randomized and rated independently by four experienced pediatric radiologists for nodule presence on a continuous scale from 0 (definitely absent) to 100 (definitely present). The receiver operating characteristic (ROC) data were analyzed to quantify the relationship between diagnostic accuracy (area under the ROC curve, AUC) and image quality (the product of nodule peak contrast and displayed diameter to noise ratio, CDNR display). AUC increased rapidly from 0.70 to 0.87 when CDNR display increased from 60 to 130 mm, followed by a slow increase to 0.94 when CDNR display further increased to 257 mm. For the average nodule diameter (4 mm) and contrast (350 HU), AUC decreased from 0.93 to 0.71 with noise increased from 7 to 28 HU. We quantified the relationship between image quality and the performance of radiologists in detecting lung nodules in pediatric CT. The relationship can guide CT protocol design to achieve the desired diagnostic performance at the lowest radiation dose.

Feasibility of epicardial adipose tissue quantification in non-ECG-gated low-radiation-dose CT: comparison with prospectively ECG-gated cardiac CT

Energy Technology Data Exchange (ETDEWEB)

Simon-Yarza, Isabel; Viteri-Ramirez, Guillermo; Saiz-Mendiguren, Ramon; Slon-Roblero, Pedro J.; Paramo, Maria [Dept. of Radiology, Clinica Univ. de Navarra, Pamplona (Spain); Bastarrika, Gorka [Dept. of Radiology, Clinica Univ. de Navarra, Pamplona (Spain); Cardiac Imaging Unit, Clinica Univ. de Navarra, Pamplona (Spain)], e-mail: bastarrika@unav.es

2012-06-15

Background: Epicardial adipose tissue (EAT) is an important indicator of cardiovascular risk. This parameter is generally assessed on ECG-gated computed tomography (CT) images. Purpose: To evaluate feasibility and reliability of EAT quantification on non-gated thoracic low-radiation-dose CT examinations with respect to prospectively ECG-gated cardiac CT acquisition. Material and Methods: Sixty consecutive asymptomatic smokers (47 men; mean age 64 {+-} 9.8 years) underwent low-dose CT of the chest and prospectively ECG-gated cardiac CT acquisitions (64-slice dual-source CT). The two examinations were reconstructed with the same range, field of view, slice thickness, and convolution algorithm. Two independent observers blindly quantified EAT volume using commercially available software. Data were compared with paired sample Student t-test, concordance correlation coefficients (CCC), and Bland-Altman plots. Results: No statistically significant difference was observed for EAT volume quantification with low-dose-CT (141.7 {+-} 58.3 mL) with respect to ECG-gated CT (142.7 {+-} 57.9 mL). Estimation of CCC showed almost perfect concordance between the two techniques for EAT-volume assessment (CCC, 0.99; mean difference, 0.98 {+-} 5.1 mL). Inter-observer agreement for EAT volume estimation was CCC: 0.96 for low-dose-CT examinations and 0.95 for ECG-gated CT. Conclusion: Non-gated low-dose CT allows quantifying EAT with almost the same concordance and reliability as using dedicated prospectively ECG-gated cardiac CT acquisition protocols.

Feasibility of epicardial adipose tissue quantification in non-ECG-gated low-radiation-dose CT: comparison with prospectively ECG-gated cardiac CT

International Nuclear Information System (INIS)

Simon-Yarza, Isabel; Viteri-Ramirez, Guillermo; Saiz-Mendiguren, Ramon; Slon-Roblero, Pedro J.; Paramo, Maria; Bastarrika, Gorka

2012-01-01

Background: Epicardial adipose tissue (EAT) is an important indicator of cardiovascular risk. This parameter is generally assessed on ECG-gated computed tomography (CT) images. Purpose: To evaluate feasibility and reliability of EAT quantification on non-gated thoracic low-radiation-dose CT examinations with respect to prospectively ECG-gated cardiac CT acquisition. Material and Methods: Sixty consecutive asymptomatic smokers (47 men; mean age 64 ± 9.8 years) underwent low-dose CT of the chest and prospectively ECG-gated cardiac CT acquisitions (64-slice dual-source CT). The two examinations were reconstructed with the same range, field of view, slice thickness, and convolution algorithm. Two independent observers blindly quantified EAT volume using commercially available software. Data were compared with paired sample Student t-test, concordance correlation coefficients (CCC), and Bland-Altman plots. Results: No statistically significant difference was observed for EAT volume quantification with low-dose-CT (141.7 ± 58.3 mL) with respect to ECG-gated CT (142.7 ± 57.9 mL). Estimation of CCC showed almost perfect concordance between the two techniques for EAT-volume assessment (CCC, 0.99; mean difference, 0.98 ± 5.1 mL). Inter-observer agreement for EAT volume estimation was CCC: 0.96 for low-dose-CT examinations and 0.95 for ECG-gated CT. Conclusion: Non-gated low-dose CT allows quantifying EAT with almost the same concordance and reliability as using dedicated prospectively ECG-gated cardiac CT acquisition protocols

Reduction of adult fingers visualized on pediatric intensive care unit (PICU) chest radiographs after radiation technologist and PICU staff radiation safety education

International Nuclear Information System (INIS)

Tynan, J.R.; Duncan, M.D.; Burbridge, B.E.

2009-01-01

A recent publication from our centre revealed a disturbing finding of a significant incidence of adult fingers seen on the pediatric intensive care unit (PICU) chest radiographs. This is inappropriate occupational exposure to diagnostic radiation. We hypothesized that the incidence of adult fingers on PICU chest radiographs would decline after radiation safety educational seminars were given to the medical radiation technologists and PICU staff. The present study's objectives were addressed by using a pretest-posttest design. Two cross-sectional PICU chest radiograph samples, taken before and after the administration of radiation safety education for our medical radiation technologists and PICU staff, were compared by using a χ 2 test. There was a 61.2% and 76.9% reduction in extraneous adult fingers, directly exposed to the x-ray beam and those seen in the coned regions of the film, respectively, on PICU chest radiographs (66.7% reduction overall). This reduction was statistically significant (χ2 = 20.613, P < .001). Limiting unnecessary occupational radiation exposure is a critical issue in radiology. There was a statistically and clinically significant association between radiation safety education and the decreased number of adult fingers seen on PICU chest radiographs. This study provides preliminary evidence in favour of the benefit of radiation safety seminars. (author)

Pitfalls and artifacts in the interpretation of oncologic PET/CT of the chest

Energy Technology Data Exchange (ETDEWEB)

Meirelles, Gustavo de Souza Portes; Capobianco, Julia; Oliveira, Marco Antonio Conde de, E-mail: gustavo.meirelles@grupofleury.com.br [Grupo Fleury, Sao Paulo, SP (Brazil)

2017-01-15

PET/CT is widely used for the evaluation of patients with thoracic malignancies. Although the levels of {sup 18}F-fluorodeoxyglucose (FDG) uptake are usually high in neoplastic diseases, they can also be physiological, due to artifacts. In addition, FDG uptake can occur in benign conditions such as infectious, inflammatory, and iatrogenic lesions. Furthermore, some malignant tumors, such as adenocarcinoma in situ (formerly known as bronchoalveolar carcinoma) and carcinoid tumors, may not show FDG uptake. Here, we illustrate the main pitfalls and artifacts in the interpretation of the results of oncologic PET/CT of the chest, outlining strategies for avoiding misinterpretation. (author)

Computed tomography of chest trauma

International Nuclear Information System (INIS)

Dinkel, E.; Uhl, H.; Reinbold, W.D.; Wimmer, B.; Wenz, W.

1987-01-01

Chest CT scans were obtained in 86 patients suffering from serious blunt or penetrating chest trauma. The finding of mediastinal widening was by far the most common CT indication. CT proved to be a more sensitive method for detection of parenchymal lung lesions and occult pneumothorax than bedside radiographs. CT contributed substantially in differentiation of lung abscess and empyema, exclusion of mediastinal pathology and spinal injuries. Aortography is still indicated, even when CT findings are normal, if aortic laceration is clinically suspected. Despite all technical problems combined with CT examinations in the critically ill patient, we consider CT a valuable diagnostic tool for selected problems in the traumatized patient. (orig.) [de

Computed tomography of chest trauma

Energy Technology Data Exchange (ETDEWEB)

Dinkel, E.; Uhl, H.; Reinbold, W.D.; Wimmer, B.; Wenz, W.

1987-09-01

Chest CT scans were obtained in 86 patients suffering from serious blunt or penetrating chest trauma. The finding of mediastinal widening was by far the most common CT indication. CT proved to be a more sensitive method for detection of parenchymal lung lesions and occult pneumothorax than bedside radiographs. CT contributed substantially in differentiation of lung abscess and empyema, exclusion of mediastinal pathology and spinal injuries. Aortography is still indicated, even when CT findings are normal, if aortic laceration is clinically suspected. Despite all technical problems combined with CT examinations in the critically ill patient, we consider CT a valuable diagnostic tool for selected problems in the traumatized patient.

System for verifiable CT radiation dose optimization based on image quality. part II. process control system.

Science.gov (United States)

Larson, David B; Malarik, Remo J; Hall, Seth M; Podberesky, Daniel J

2013-10-01

To evaluate the effect of an automated computed tomography (CT) radiation dose optimization and process control system on the consistency of estimated image noise and size-specific dose estimates (SSDEs) of radiation in CT examinations of the chest, abdomen, and pelvis. This quality improvement project was determined not to constitute human subject research. An automated system was developed to analyze each examination immediately after completion, and to report individual axial-image-level and study-level summary data for patient size, image noise, and SSDE. The system acquired data for 4 months beginning October 1, 2011. Protocol changes were made by using parameters recommended by the prediction application, and 3 months of additional data were acquired. Preimplementation and postimplementation mean image noise and SSDE were compared by using unpaired t tests and F tests. Common-cause variation was differentiated from special-cause variation by using a statistical process control individual chart. A total of 817 CT examinations, 490 acquired before and 327 acquired after the initial protocol changes, were included in the study. Mean patient age and water-equivalent diameter were 12.0 years and 23.0 cm, respectively. The difference between actual and target noise increased from -1.4 to 0.3 HU (P process control chart identified several special causes of variation. Implementation of an automated CT radiation dose optimization system led to verifiable simultaneous decrease in image noise variation and SSDE. The automated nature of the system provides the opportunity for consistent CT radiation dose optimization on a broad scale. © RSNA, 2013.

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

Science.gov (United States)

Schenzle, Jan C; Sommer, Wieland H; Neumaier, Klement; Michalski, Gisela; Lechel, Ursula; Nikolaou, Konstantin; Becker, Christoph R; Reiser, Maximilian F; Johnson, Thorsten R C

2010-06-01

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). Also, exact effective dose length products (E/DLP) conversion factors were to be established based on the objectively measured dose. An anthropomorphic Alderson phantom was assembled with thermoluminescent detectors (TLD) and its chest was scanned on a Dual Source CT (Siemens Somatom Definition) in dual energy mode at 140 and 80 kVp with 14 x 1.2 mm collimation. The same was performed on another Dual Source CT (Siemens Somatom Definition Flash) at 140 kVp with 0.8 mm tin filter (Sn) and 100 kVp at 128 x 0.6 mm collimation. Reference scans were obtained at 120 kVp with 64 x 0.6 mm collimation at equivalent CT dose index of 5.4 mGy*cm. Syringes filled with water and 17.5 mg iodine/mL were scanned with the same settings. Dose was calculated from the TLD measurements and the dose length products of the scanner. Image noise was measured in the phantom scans and CNR and spectral contrast were determined in the iodine and water samples. E/DLP conversion factors were calculated as ratio between the measured dose form the TLDs and the dose length product given in the patient protocol. The effective dose measured with TLDs was 2.61, 2.69, and 2.70 mSv, respectively, for the 140/80 kVp, the 140 Sn/100 kVp, and the standard 120 kVp scans. Image noise measured in the average images of the phantom scans was 11.0, 10.7, and 9.9 HU (P > 0.05). The CNR of iodine with optimized image blending was 33.4 at 140/80 kVp, 30.7 at 140Sn/100 kVp and 14.6 at 120 kVp. E/DLP conversion factors were 0.0161 mSv/mGy*cm for the 140/80 kVp protocol, 0.0181 m

Poster — Thur Eve — 06: Dose assessment of cone beam CT imaging protocols as part of SPECT/CT examinations

Energy Technology Data Exchange (ETDEWEB)

Tonkopi, E; Ross, AA [Department of Diagnostic Imaging, Queen Elizabeth II Health Sciences Centre, CDHA (Canada); Department of Radiology, Dalhousie University (Canada)

2014-08-15

Purpose: To assess radiation dose from the cone beam CT (CBCT) component of SPECT/CT studies and to compare with other CT examinations performed in our institution. Methods: We used an anthropomorphic chest phantom and the 6 cc ion chamber to measure entrance breast dose for several CBCT and diagnostic CT acquisition protocols. The CBCT effective dose was calculated with ImPACT software; the CT effective dose was evaluated from the DLP value and conversion factor, dependent on the anatomic region. The RADAR medical procedure radiation dose calculator was used to assess the nuclear medicine component of exam dose. Results: The entrance dose to the breast measured with the anthropomorphic phantom was 0.48 mGy and 9.41 mGy for cardiac and chest CBCT scans; and 4.59 mGy for diagnostic thoracic CT. The effective doses were 0.2 mSv, 3.2 mSv and 2.8 mSv respectively. For a small patient represented by the anthropomorphic phantom, the dose from the diagnostic CT was lower than from the CBCT scan, as a result of the exposure reduction options available on modern CT scanners. The CBCT protocols used the same fixed scanning techniques. The diagnostic CT dose based on the patient data was 35% higher than the phantom dose. For most SPECT/CT studies the dose from the CBCT component was comparable with the dose from the radiopharmaceutical. Conclusions: The patient radiation dose from the cone beam CT scan can be higher than that from a diagnostic CT and should be taken into consideration in evaluating total SPECT/CT patient dose.

Investigation of the dosimetry of chest tomosynthesis

Science.gov (United States)

Svalkvist, Angelica; Zachrisson, Sara; Månsson, Lars Gunnar; Båth, Magnus

2009-02-01

Chest tomosynthesis has recently been introduced to healthcare as a low-dose alternative to CT or as a tool for improved diagnostics in chest radiography with only a modest increase in radiation dose to the patient. However, no detailed description of the dosimetry for this type of examination has been presented. The aim of this work was therefore to investigate the dosimetry of chest tomosynthesis. The chest tomosynthesis examination was assumed to be performed using a stationary detector and a vertically moving x-ray tube, exposing the patient from different angles. The Monte Carlo based computer software PCXMC was used to determine the effective dose delivered to a standard-sized patient from various angles using different assumptions of the distribution of the effective dose over the different projections. The obtained conversion factors between input dose measures and effective dose for chest tomosynthesis for different angular intervals were then compared with the horizontal projection. The results indicate that the error introduced by using conversion factors for the PA projection in chest radiography for estimating the effective dose of chest tomosynthesis is small for normally sized patients, especially if a conversion factor between KAP and effective dose is used.

Abnormal chest shadow on CT in immunosuppressed patients

International Nuclear Information System (INIS)

Tanaka, Nobuyuki; Matsumoto, Tsuneo; Nakamura, Hiroshi

1992-01-01

An abnormal chest shadow was observed on CT scans in 25 cases of 23 immunosuppressed patients. Pulmonary disease was pathologically confirmed to be pneumocystis carinii pneumonia (PC pneumonia) in four patients, cytomegalovirus pneumonia (CMV pneumonia) in one, bacterial pneumonia in seven, fungal infection in three, miliary tuberculosis in one, leukemic infiltration in two, lymphangitis carcinomatosa in three, drug-induced pneumonitis in three, and ARDS in one. In almost all patients, especially those with infectious diseases such as PC pneumonia, CMV pneumonia, and bacterial pneumonia, the abnormal shadow was wide and visible in the bilateral lung fields. We presumed that such findings as lobular shadow, centrilobular shadow, and mosaic pattern reflected the extension of disease via the respiratory tract, and that those findings are typical of infectious diseases. Because such findings as abnormal linear shadow and swelling of a broncho-vascular bundle were very frequently recognized in patients with lymphangitis carcinomatosa and frequently recognized in those with drug-induced pneumonitis, these diseases may be distinguished from other diseases. An area of slightly increased density was frequently recognized in patients with PC pneumonia, bacterial pneumonia, and drug-induced pneumonitis. Such lesions were pathologically confirmed to be located in the interstitium and/or alveolus. CT was extremely useful in comprehending the character and extension of particular diseases among various diseases. As the number of patients studied was small, the utility of CT in immunosuppressed patients requires further investigation in a larger number of patients. (author)

Interactive lung segmentation in abnormal human and animal chest CT scans

International Nuclear Information System (INIS)

Kockelkorn, Thessa T. J. P.; Viergever, Max A.; Schaefer-Prokop, Cornelia M.; Bozovic, Gracijela; Muñoz-Barrutia, Arrate; Rikxoort, Eva M. van; Brown, Matthew S.; Jong, Pim A. de; Ginneken, Bram van

2014-01-01

Purpose: Many medical image analysis systems require segmentation of the structures of interest as a first step. For scans with gross pathology, automatic segmentation methods may fail. The authors’ aim is to develop a versatile, fast, and reliable interactive system to segment anatomical structures. In this study, this system was used for segmenting lungs in challenging thoracic computed tomography (CT) scans. Methods: In volumetric thoracic CT scans, the chest is segmented and divided into 3D volumes of interest (VOIs), containing voxels with similar densities. These VOIs are automatically labeled as either lung tissue or nonlung tissue. The automatic labeling results can be corrected using an interactive or a supervised interactive approach. When using the supervised interactive system, the user is shown the classification results per slice, whereupon he/she can adjust incorrect labels. The system is retrained continuously, taking the corrections and approvals of the user into account. In this way, the system learns to make a better distinction between lung tissue and nonlung tissue. When using the interactive framework without supervised learning, the user corrects all incorrectly labeled VOIs manually. Both interactive segmentation tools were tested on 32 volumetric CT scans of pigs, mice and humans, containing pulmonary abnormalities. Results: On average, supervised interactive lung segmentation took under 9 min of user interaction. Algorithm computing time was 2 min on average, but can easily be reduced. On average, 2.0% of all VOIs in a scan had to be relabeled. Lung segmentation using the interactive segmentation method took on average 13 min and involved relabeling 3.0% of all VOIs on average. The resulting segmentations correspond well to manual delineations of eight axial slices per scan, with an average Dice similarity coefficient of 0.933. Conclusions: The authors have developed two fast and reliable methods for interactive lung segmentation in

On-demand rather than daily-routine chest radiography prescription may change neither the number nor the impact of chest computed tomography and ultrasound studies in a multidisciplinary intensive care unit.

Science.gov (United States)

Kröner, Anke; Binnekade, Jan M; Graat, Marleen E; Vroom, Margreeth B; Stoker, Jaap; Spronk, Peter E; Schultz, Marcus J

2008-01-01

Elimination of daily-routine chest radiographs (CXRs) may influence chest computed tomography (CT) and ultrasound practice in critically ill patients. This was a retrospective cohort study including all patients admitted to a university-affiliated intensive care unit during two consecutive periods of 5 months, one before and one after elimination of daily-routine CXR. Chest CT and ultrasound studies were identified retrospectively by using the radiology department information system. Indications for and the diagnostic/therapeutic yield of chest CT and ultrasound studies were collected. Elimination of daily-routine CXR resulted in a decrease of CXRs per patient day from 1.1 +/- 0.3 to 0.6 +/- 0.4 (P chest CT studies nor the ratio of chest CT studies per patient day changed with the intervention: Before elimination of daily-routine CXR, 52 chest CT studies were obtained from 747 patients; after elimination, 54 CT studies were obtained from 743 patients. Similarly, chest ultrasound practice was not affected by the change of CXR strategy: Before and after elimination, 21 and 27 chest ultrasound studies were performed, respectively. Also, timing of chest CT and ultrasound studies was not different between the two study periods. During the two periods, 40 of 106 chest CT studies (38%) and 18 of 48 chest ultrasound studies (38%) resulted in a change in therapy. The combined therapeutic yield of chest CT and ultrasound studies did not change with elimination of daily-routine CXR. Elimination of daily-routine CXRs may not affect chest CT and ultrasound practice in a multidisciplinary intensive care unit.

Experimental article – Maintaining image quality for paediatric chest CTs while lowering dose : FBP versus SAFIRE

NARCIS (Netherlands)

Borgea, Synnøve; Campbell, Nina; Gomes, Ana; Raszkowskia, Aysha M.; Rook, Jan Willem; Sanderud, Audun; Vallinga, Anique; Buissink, Carst; Vouillamoze, Audrey

2015-01-01

Objectives: Children have a greater risk from radiation, per unit dose, due to increased radiosensitivity and longer life expectancies. It is of paramount importance to reduce the radiation dose received by children. This research concerns chest CT examinations on paediatric patients. The purpose of

Focal breast lesions in clinical CT examinations of the chest. A retrospective analysis

International Nuclear Information System (INIS)

Krug, Kathrin Barbara; Houbois, Christian; Grinstein, Olga; Borggrefe, Jan; Puesken, Michael; Maintz, David; Hanstein, Bettina; Malter, Wolfram; Hellmich, Martin

2017-01-01

Based on radiological reports, the percentage of breast cancers visualized as incidental findings in routine CT examinations is estimated at ≤2%. In view of the rising number of CT examinations and the high prevalence of breast cancer, it was the goal of the present study to verify the frequency and image morphology of false-negative senological CT findings. All first contrast-enhanced CT examinations of the chest in adult female patients carried out in 2012 were retrospectively included. A senior radiologist systematically assessed the presence of breast lesions on all CT images using the BI-RADS system. All BI-RADS ≥3 notations were evaluated by a second senior radiologist. A consensus was obtained in case of differing BI-RADS assessments. Reference diagnoses were elaborated based on all available clinical, radiological and pathological data. The findings of the CT reports were classified according to the BI-RADS system and were compared with the retrospective consensus findings as well as with the reference diagnoses. The range of indications comprised a broad spectrum including staging and follow-up examinations of solid tumors/lymphoma (N = 701, 59.9 %) and vascular (190, 16.2 %), inflammatory (48, 4.1 %) and pulmonologic (22, 1.9 %) issues. BI-RADS 1/2 classifications were present in 92.5 % and BI-RADS 6 classifications were assessed in 1.7 % of the 1170 included examinations. 68 patients (5.8 %) had at least one lesion retrospectively classified as BI-RADS 3 - 5. The histological potential was known in 57 of these lesions as benign (46, 3.9 %) or malignant (11, 0.9 %). 13 BI-RADS 4/5 consensus assessments (1.1 %) were false-positive. 2 of the 10 lesions classified as being malignant based on the further clinical and radiological course were not mentioned in the written CT reports (0.2 %). Both false-negative CT reports were therapeutically and prognostically irrelevant. The relative frequency of BI-RADS 3 - 5 findings was 5.8 %. It reflects the situation

Computed tomography of chest wall abscess

International Nuclear Information System (INIS)

Ikezoe, Junpei; Morimoto, Shizuo; Akira, Masanori

1986-01-01

Inflammatory lesions of the chest wall become less common because of the improvement of antibiotics and chemotherapeutic agents. Over a 5-year period, 7 patients with chest wall inflammatory diseases underwent chest computed tomography. These were 2 tuberculous pericostal abscesses, 2 empyema necessitatis, 1 spinal caries, and 2 bacterial chest wall abscesses (unknown organisms). Computed tomography (CT) helped in demonstrating the density, border, site, and extent of the lesions. CT images also demonstrated the accompaning abnormalities which included bone changes, pleural calcification, or old tuberculous changes of the lung. CT was very effective to demonstrate the communicating portions from the inside of the bony thorax to the outside of the bony thorax in 2 empyema necessitatis. (author)

Prevalence and Clinical Import of Thoracic Injury Identified by Chest Computed Tomography but Not Chest Radiography in Blunt Trauma: Multicenter Prospective Cohort Study.

Science.gov (United States)

Langdorf, Mark I; Medak, Anthony J; Hendey, Gregory W; Nishijima, Daniel K; Mower, William R; Raja, Ali S; Baumann, Brigitte M; Anglin, Deirdre R; Anderson, Craig L; Lotfipour, Shahram; Reed, Karin E; Zuabi, Nadia; Khan, Nooreen A; Bithell, Chelsey A; Rowther, Armaan A; Villar, Julian; Rodriguez, Robert M

2015-12-01

Chest computed tomography (CT) diagnoses more injuries than chest radiography, so-called occult injuries. Wide availability of chest CT has driven substantial increase in emergency department use, although the incidence and clinical significance of chest CT findings have not been fully described. We determine the frequency, severity, and clinical import of occult injury, as determined by changes in management. These data will better inform clinical decisions, need for chest CT, and odds of intervention. Our sample included prospective data (2009 to 2013) on 5,912 patients at 10 Level I trauma center EDs with both chest radiography and chest CT at physician discretion. These patients were 40.6% of 14,553 enrolled in the parent study who had either chest radiography or chest CT. Occult injuries were pneumothorax, hemothorax, sternal or greater than 2 rib fractures, pulmonary contusion, thoracic spine or scapula fracture, and diaphragm or great vessel injury found on chest CT but not on preceding chest radiography. A priori, we categorized thoracic injuries as major (having invasive procedures), minor (observation or inpatient pain control >24 hours), or of no clinical significance. Primary outcome was prevalence and proportion of occult injury with major interventions of chest tube, mechanical ventilation, or surgery. Secondary outcome was minor interventions of admission rate or observation hours because of occult injury. Two thousand forty-eight patients (34.6%) had chest injury on chest radiography or chest CT, whereas 1,454 of these patients (71.0%, 24.6% of all patients) had occult injury. Of these, in 954 patients (46.6% of injured, 16.1% of total), chest CT found injuries not observed on immediately preceding chest radiography. In 500 more patients (24.4% of injured patients, 8.5% of all patients), chest radiography found some injury, but chest CT found occult injury. Chest radiography found all injuries in only 29.0% of injured patients. Two hundred and two

Radiation risk from CT: implications for cancer screening.

Science.gov (United States)

Albert, Jeffrey M

2013-07-01

The cancer risks associated with patient exposure to radiation from medical imaging have become a major topic of debate. The higher doses necessary for technologies such as CT and the increasing utilization of these technologies further increase medical radiation exposure to the population. Furthermore, the use of CT for population-based cancer screening continues to be explored for common malignancies such as lung cancer and colorectal cancer. Given the known carcinogenic effects of ionizing radiation, this warrants evaluation of the balance between the benefit of early cancer detection and the risk of screening-induced malignancy. This report provides a brief review of the process of radiation carcino-genesis and the literature evaluating the risk of malignancy from CT, with a focus on the risks and benefits of CT for cancer screening. The available data suggest a small but real risk of radiation-induced malignancy from CT that could become significant at the population level with widespread use of CT-based screening. However, a growing body of literature suggests that the benefits of CT screening for lung cancer in high-risk patients and CT colonography for colorectal cancer may significantly outweigh the radiation risk. Future studies evaluating the benefits of CT screening should continue to consider potential radiation risks.

Long-Term Clinical Impact of Coronary CT Angiography in Patients With Recent Acute-Onset Chest Pain

DEFF Research Database (Denmark)

Linde, Jesper J; Hove, Jens D; Sørgaard, Mathias

2015-01-01

. BACKGROUND: The prognostic implications of a coronary CTA-guided treatment strategy have not been compared in a randomized fashion to standard care in patients referred for acute-onset chest pain. METHODS: Patients with acute chest pain but normal electrocardiograms and troponin values were randomized...... to treatment guided by either coronary CTA or standard care (bicycle exercise electrocardiogram or myocardial perfusion imaging). In the coronary CTA-guided group, a functional test was included in cases of nondiagnostic coronary CTA images or coronary stenoses of borderline severity. The primary endpoint...... electrocardiograms and troponin values compared to standard care with a functional test. (Cardiac-CT in the Treatment of Acute Chest Pain [CATCH]; NCT01534000)....

CT imaging of congenital lung lesions: effect of iterative reconstruction on diagnostic performance and radiation dose

International Nuclear Information System (INIS)

Haggerty, Jay E.; Smith, Ethan A.; Dillman, Jonathan R.; Kunisaki, Shaun M.

2015-01-01

Different iterative reconstruction techniques are available for use in pediatric computed tomography (CT), but these techniques have not been systematically evaluated in infants. To determine the effect of iterative reconstruction on diagnostic performance, image quality and radiation dose in infants undergoing CT evaluation for congenital lung lesions. A retrospective review of contrast-enhanced chest CT in infants (<1 year) with congenital lung lesions was performed. CT examinations were reviewed to document the type of lung lesion, vascular anatomy, image noise measurements and image reconstruction method. CTDI vol was used to calculate size-specific dose estimates (SSDE). CT findings were correlated with intraoperative and histopathological findings. Analysis of variance and the Student's t-test were used to compare image noise measurements and radiation dose estimates between groups. Fifteen CT examinations used filtered back projection (FBP; mean age: 84 days), 15 used adaptive statistical iterative reconstruction (ASiR; mean age: 93 days), and 11 used model-based iterative reconstruction (MBIR; mean age: 98 days). Compared to operative findings, 13/15 (87%), 14/15 (93%) and 11/11 (100%) lesions were correctly characterized using FBP, ASiR and MBIR, respectively. Arterial anatomy was correctly identified in 12/15 (80%) using FBP, 13/15 (87%) using ASiR and 11/11 (100%) using MBIR. Image noise was less for MBIR vs. ASiR (P < 0.0001). Mean SSDE was different among groups (P = 0.003; FBP = 7.35 mGy, ASiR = 1.89 mGy, MBIR = 1.49 mGy). Congenital lung lesions can be adequately characterized in infants using iterative CT reconstruction techniques while maintaining image quality and lowering radiation dose. (orig.)

CT imaging of congenital lung lesions: effect of iterative reconstruction on diagnostic performance and radiation dose

Energy Technology Data Exchange (ETDEWEB)

Haggerty, Jay E.; Smith, Ethan A.; Dillman, Jonathan R. [University of Michigan Health System, Section of Pediatric Radiology, Department of Radiology, C.S. Mott Children' s Hospital, Ann Arbor, MI (United States); Kunisaki, Shaun M. [University of Michigan Health System, Section of Pediatric Surgery, Department of Surgery, C.S. Mott Children' s Hospital, Ann Arbor, MI (United States)

2015-07-15

Different iterative reconstruction techniques are available for use in pediatric computed tomography (CT), but these techniques have not been systematically evaluated in infants. To determine the effect of iterative reconstruction on diagnostic performance, image quality and radiation dose in infants undergoing CT evaluation for congenital lung lesions. A retrospective review of contrast-enhanced chest CT in infants (<1 year) with congenital lung lesions was performed. CT examinations were reviewed to document the type of lung lesion, vascular anatomy, image noise measurements and image reconstruction method. CTDI{sub vol} was used to calculate size-specific dose estimates (SSDE). CT findings were correlated with intraoperative and histopathological findings. Analysis of variance and the Student's t-test were used to compare image noise measurements and radiation dose estimates between groups. Fifteen CT examinations used filtered back projection (FBP; mean age: 84 days), 15 used adaptive statistical iterative reconstruction (ASiR; mean age: 93 days), and 11 used model-based iterative reconstruction (MBIR; mean age: 98 days). Compared to operative findings, 13/15 (87%), 14/15 (93%) and 11/11 (100%) lesions were correctly characterized using FBP, ASiR and MBIR, respectively. Arterial anatomy was correctly identified in 12/15 (80%) using FBP, 13/15 (87%) using ASiR and 11/11 (100%) using MBIR. Image noise was less for MBIR vs. ASiR (P < 0.0001). Mean SSDE was different among groups (P = 0.003; FBP = 7.35 mGy, ASiR = 1.89 mGy, MBIR = 1.49 mGy). Congenital lung lesions can be adequately characterized in infants using iterative CT reconstruction techniques while maintaining image quality and lowering radiation dose. (orig.)

Application of triple rule-out with 64-slice spiral CT in the diagnosis of acute chest pain

International Nuclear Information System (INIS)

Li Pengyu; Li Kuncheng; Du Xiangyin; Cao Lizhen; Liu Jiabin; Yang Yanhuui; Liang Zhigang; Zhu Xiaolian; Liu Jian

2007-01-01

Objective: To investigate the performance of triple rule-out with 64-slice spiral CT in the combined examination of pulmonary artery, thoracic aorta and coronary artery for patients with acute chest pain. Methods: Seventy patients who presented with acute chest pain were included in the study. All of the patients underwent retrospective ECG-gated 64-slice computed tomography triple rule-out examination to evaluate the pulmonary arteries, thoracic aorta and coronary arteries. Multi-planar reconstruction (MPR), maximum intensity projection (MIP), curved-planar reconstruction (CPR) and volume rendering (VR) were used to display pulmonary arteries, thoracic aorta and coronary arteries. We evaluated the image quality of coronary artery and the enhancement of the pulmonary artery and thoracic aorta to estimate if the examination can fulfill the clinical demand for the differential diagnosis of acute chest pain. Results: The mean scan time was (8.5±1.0) s, and the dose of contrast medium injected was 100 ml. There were 95.7% (67/70) of patients whose CT values detected in the pulmonary artery and thoracic aorta after enhancement Were ≥200 HU. The image quality of 85.8% (720/839) coronary segments was classified as excellent, 8.6% (72/839) as good, and 5.6% (47/839) as poor. There were 20 eases with coronary stenoses ≥50%, 2 cases with pulmonary embolism, and 2 cases with aortic dissection. Conclusion: The triple rule-out examination with 64-slice spiral CT could depict pulmonary artery, thoracic aorta, and coronary artery in 8 s with good image quality. It has great potential in the etiological diagnosis for the patients with acute chest pain. (authors)

Technique and clinical applications of full-inflation and end-exhalation controlled-ventilation chest CT in infants and young children

International Nuclear Information System (INIS)

Long, F.R.; Castile, R.G.

2001-01-01

Background. The inability of young children to cooperate with breath holding limits the usefulness of chest CT. Objective. To describe the technique and utility of a non-invasive method called controlled-ventilation CT (CVCT) for obtaining motion-free full-inflation and end-exhalation images of the lung in infants and young children. Materials and methods. Eighty-seven children (ages 1 week to 5 years, mean 2 years) underwent CVCT of the chest during suspended respiration at full-lung inflation and end-exhalation for a variety of clinical indications. Respiratory pauses were produced using conscious sedation and positive-pressure face-mask ventilation. Forty-one of 87 children had recordings of respiratory motion during CVCT. Results. Respiratory pause lengths increased with age (P < 0.003), were highly reproducible (r = 0.85), and lasted sufficiently long to be practical for full-inflation (24 ± 9 s) and end-exhalation (12 ± 5 s) CT scanning. Full-inflation CVCT was useful in evaluating tracheal and bronchial stenosis, bronchial wall thickening, early bronchiectasis, bronchial fistula, extent of interstitial fibrosis, and lung nodules. End-exhalation CVCT was useful in evaluating tracheomalacia and air trapping. Conclusion. Controlled-ventilation chest CT is a practical and reliable technique that promises to be clinically useful for a number of clinical indications in infants and young children. (orig.)

Chest CT study of patients with asbestos exposure, 1

International Nuclear Information System (INIS)

Hatakeyama, Masayuki

1988-01-01

Thin-slice high-resolution computed tomographic (CT) findings of 36 patients (34 men, 2 women) with histories of long-term (11 to 43 years) occupational asbestos exposure (AS) were analyzed for pulmonary abnormalities, which were classified by the subpleural curvilinear shadow (SCLS) and/or the extent of honeycomb shadow (HS) into five types (O to IV). SCLS was detected in 22 patients (62 %), and HS in 14 patients (39 %). SCLS was distributed mainly in the lower lobe in patients with mild pulmonary fibrosis (Types I and II) and in segments where fibrosis was mild in patients with HS (Types III and IV). This may reflect the initiation of pulmonary fibrosis leading to the formation of a HS. Most (63.7 %) SCLS measured > 5 cm but < 10 cm in length and occurred < 1 cm from the inner chest wall in all cases. Radiologic-pathologic correlation of SCLS and HS in CT imagings, achieved in two post mortem specimens, seemed to indicate that SCLS was associated with the initial change of fibrosing bronchiolo-alveolitis, which is characteristic of pulmonary asbestosis. Thin-slice high-resolution CT findings of 36 patients with AS and 33 patients with idiopathic interstitial pneumonia (IIP) were compared. Though the incidence of SCLS was low (21 %) in this series of IIP, its presence suggests that SCLS is not specific to pulmonary asbestosis but occurs also in chronic interstitial pneumonia. In order to explore the mechanism of the appearance of SCLS, further analysis of CT and histopathologic findings not only of pulmonary asbestosis and IIP but also of many other pulmonary interstitial diseases is necessary. It could be considered that thin-slice high-resolution CT which first detected SCLS is very useful in the visualization of fine structures of the lungs. (author)

Imaging of chest wall infections

International Nuclear Information System (INIS)

Chelli Bouaziz, Mouna; Jelassi, Helmi; Chaabane, Skander; Ladeb, Mohamed Fethi; Ben Miled-Mrad, Khaoula

2009-01-01

A wide variety of infections can affect the chest wall including pyogenic, tuberculous, fungal, and some other unusual infections. These potentially life-threatening disorders are frequent especially among immunocompromised patients but often misdiagnosed by physical examination and radiographs. The purpose of this article is to describe the clinical and imaging features of these different chest wall infections according to the different imaging modalities with emphasis on ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). The outcome of chest wall infection depends on early diagnosis, severity of the immunosuppression, offending organism, and extent of infection. Because clinical findings and laboratory tests may be not contributive in immunocompromised patients, imaging plays an important role in the early detection and precise assessment of the disease. US, CT, and MRI are all useful: bone destruction is more accurately detected with CT whereas soft tissue involvement are better visualized with US and MRI. CT and US are also used to guide percutaneous biopsy and drainage procedures. MR images are helpful in pre-operative planning of extensive chest wall infections. (orig.)

Imaging of blunt chest trauma

International Nuclear Information System (INIS)

Prosch, H.; Negrin, L.

2014-01-01

Blunt chest trauma is associated with high morbidity and mortality. Consequently, all patients should be evaluated radiologically after blunt chest trauma to allow timely and appropriate treatment. Conventional chest radiographs and computed tomography (CT) are proven modalities with which to evaluate patients after blunt chest trauma. Over the last several years extended focused assessment with sonography for trauma (eFAST) has gained increasing importance for the initial assessment of seriously injured patients. In the acute phase of severely injured patients eFAST examinations are helpful to exclude pneumothorax, hemothorax and hemopericardium. Chest radiographs may also be used to diagnose a pneumothorax or hemothorax; however, the sensitivity is limited and CT is the diagnostic modality of choice to evaluate severely injured patients. (orig.) [de

Role of computed tomography in blunt chest trauma

International Nuclear Information System (INIS)

Cho, Jae Hyun; Kim, Sang Jin; Lee, Chan Wha; Kim, Hae Kyoon

1994-01-01

In patient with blunt trauma of chest, supine AP x-ray cannot differentiate the lung contusion, laceration, atelectasis, and hemothorax definitely. Therefore, computed tomographic evaluation is needed for accurate evaluation of the injuries. In our knowledge, there are few reports about CT findings of blunt chest trauma, in our country, therefore we tried to fluid the characteristic CT findings in patients with blunt trauma. We analyzed the plain x-ray and CT image of 4 patients with blunt chest trauma. Location and morphology of lung parenchymal contusion and laceration, hemopneumothorax, chest wall injuries and location of chest tube. Lung parenchymal contusion was noted in 53 segments., of 16 patients infiltration(n=27 segment), and multiple nodular pattern was noted in 15 segment, pattern of consolidation along the lung periphery was seen in 11 segment. Laceration was noted in 18 lesion and most commonly located in paravertebral area(b=8). CT scan of chest in patient with blunt chest trauma, provides accurate information of the pattern of injuries, and localization, therefore, should be performed as possible

In diagnosis of pleural effusion and pneumothorax in the intensive care unit patients: Can chest us replace bedside plain radiography?

Directory of Open Access Journals (Sweden)

ElShaimaa Mohamed Mohamed

2018-06-01

Conclusions: In evaluation of ICU patients with pleural effusion and pneumothorax, chest US is the first bedside tool with high diagnostic performance. These chest conditions are urgent especially in seriously ill patients, as both need US guided drainage. Chest US has many advantages, including non invasive examination in multiple planes, free of radiation hazard, less expensive, real-time, high sensitivity and diagnostic accuracy in chest lesions detection. Lung ultrasound is being exclusive than bedside chest X-ray and equal to chest CT in diagnosing pleural effusion and pneumothorax.

Mediastinal lymph node detection and station mapping on chest CT using spatial priors and random forest

Energy Technology Data Exchange (ETDEWEB)

Liu, Jiamin; Hoffman, Joanne; Zhao, Jocelyn; Yao, Jianhua; Lu, Le; Kim, Lauren; Turkbey, Evrim B.; Summers, Ronald M., E-mail: rms@nih.gov [Imaging Biomarkers and Computer-aided Diagnosis Laboratory, Radiology and Imaging Sciences, National Institutes of Health Clinical Center Building, 10 Room 1C224 MSC 1182, Bethesda, Maryland 20892-1182 (United States)

2016-07-15

Purpose: To develop an automated system for mediastinal lymph node detection and station mapping for chest CT. Methods: The contextual organs, trachea, lungs, and spine are first automatically identified to locate the region of interest (ROI) (mediastinum). The authors employ shape features derived from Hessian analysis, local object scale, and circular transformation that are computed per voxel in the ROI. Eight more anatomical structures are simultaneously segmented by multiatlas label fusion. Spatial priors are defined as the relative multidimensional distance vectors corresponding to each structure. Intensity, shape, and spatial prior features are integrated and parsed by a random forest classifier for lymph node detection. The detected candidates are then segmented by the following curve evolution process. Texture features are computed on the segmented lymph nodes and a support vector machine committee is used for final classification. For lymph node station labeling, based on the segmentation results of the above anatomical structures, the textual definitions of mediastinal lymph node map according to the International Association for the Study of Lung Cancer are converted into patient-specific color-coded CT image, where the lymph node station can be automatically assigned for each detected node. Results: The chest CT volumes from 70 patients with 316 enlarged mediastinal lymph nodes are used for validation. For lymph node detection, their system achieves 88% sensitivity at eight false positives per patient. For lymph node station labeling, 84.5% of lymph nodes are correctly assigned to their stations. Conclusions: Multiple-channel shape, intensity, and spatial prior features aggregated by a random forest classifier improve mediastinal lymph node detection on chest CT. Using the location information of segmented anatomic structures from the multiatlas formulation enables accurate identification of lymph node stations.

Mediastinal lymph node detection and station mapping on chest CT using spatial priors and random forest

International Nuclear Information System (INIS)

Liu, Jiamin; Hoffman, Joanne; Zhao, Jocelyn; Yao, Jianhua; Lu, Le; Kim, Lauren; Turkbey, Evrim B.; Summers, Ronald M.

2016-01-01

Purpose: To develop an automated system for mediastinal lymph node detection and station mapping for chest CT. Methods: The contextual organs, trachea, lungs, and spine are first automatically identified to locate the region of interest (ROI) (mediastinum). The authors employ shape features derived from Hessian analysis, local object scale, and circular transformation that are computed per voxel in the ROI. Eight more anatomical structures are simultaneously segmented by multiatlas label fusion. Spatial priors are defined as the relative multidimensional distance vectors corresponding to each structure. Intensity, shape, and spatial prior features are integrated and parsed by a random forest classifier for lymph node detection. The detected candidates are then segmented by the following curve evolution process. Texture features are computed on the segmented lymph nodes and a support vector machine committee is used for final classification. For lymph node station labeling, based on the segmentation results of the above anatomical structures, the textual definitions of mediastinal lymph node map according to the International Association for the Study of Lung Cancer are converted into patient-specific color-coded CT image, where the lymph node station can be automatically assigned for each detected node. Results: The chest CT volumes from 70 patients with 316 enlarged mediastinal lymph nodes are used for validation. For lymph node detection, their system achieves 88% sensitivity at eight false positives per patient. For lymph node station labeling, 84.5% of lymph nodes are correctly assigned to their stations. Conclusions: Multiple-channel shape, intensity, and spatial prior features aggregated by a random forest classifier improve mediastinal lymph node detection on chest CT. Using the location information of segmented anatomic structures from the multiatlas formulation enables accurate identification of lymph node stations.

Computer-aided detection of lung nodules on chest CT: issues to be solved before clinical use

International Nuclear Information System (INIS)

Goo, Jin Mo

2005-01-01

Given the increasing resolution of modern CT scanners, and the requirements for large-scale lung-screening examinations and diagnostic studies, there is an increased need for the accurate and reproducible analysis of the large number of images. Nodule detection is one of the main challenges of CT imaging, as they can be missed due to their small size, low relative contrast, or because they are located in an area with complex anatomy. Recent developments in computer-aided diagnosis (CAD) schemes are expected to aid radiologists in various tasks of chest imaging. In this era of multidetector row CT, the thoracic applications of greatest interest include the detection and volume measurement of lung nodules (1-7). Technology for CAD as applied to lung nodule detection on chest CT has been approved by the Food and Drug Administration and is currently commercially available. The article by Lee et al. (5) in this issue of the Korean Journal of Radiology is one of the few studies to examine the influence of a commercially available CAD system on the detection of lung nodules. In this study, some additional nodules were detected with the help of a CAD system, but at the expense of increased false positivity. The nodule detection rate of the CAD system in this study was lower than that achieved by radiologist, and the authors insist that the CAD system should be improved further. Compared to the use of CAD on mammograms, CAD evaluations of chest CTs remain limited to the laboratory setting. In this field, apart from the issues of detection rate and false positive detections, many obstacles must be overcome before CAD can be used in a true clinical reading environment. In this editorial, I will list some of these issues, but I emphasize now that I believe these issues will be solved by improved CAD versions in the near future

Assessment of effective dose from cone beam CT imaging in SPECT/CT examination in comparison with other modalities

International Nuclear Information System (INIS)

Tonkopi, Elena; Ross, Andrew A.

2016-01-01

The aim of this study was to assess radiation dose from the cone beam computed tomography (CBCT) component of single photon emission tomography/computed tomography (SPECT/CT) examinations and to compare it with the radiopharmaceutical related dose as well as dose from multidetector computed tomography (MDCT). Effective dose (ED) from computed tomography (CT) was estimated using dose-length product values and anatomy-specific conversion factors. The contribution from the SPECT component was evaluated using ED per unit administered activity for the radiopharmaceuticals listed in the International Commission on Radiological Protection Publications 80 and 106. With the exception of cardiac studies (0.11 mSv), the CBCT dose (3.96-6.04 mSv) was similar to that from the radiopharmaceutical accounting for 29-56 % of the total ED from the examination. In comparison with MDCT examinations, the CBCT dose was 48 and 42 % lower for abdomen/pelvis and chest/abdomen/pelvis scans, respectively, while in the chest the CBCT scan resulted in higher dose (23 %). Radiation dose from the CT component should be taken into consideration when evaluating total SPECT/CT patient dose. (authors)

Role of contrast-enhanced helical CT in the evaluation of acute thoracic aortic injuries after blunt chest trauma

International Nuclear Information System (INIS)

Scaglione, M.; Pinto, A.; Pinto, F.; Romano, L.; Ragozzino, A.; Grassi, R.

2001-01-01

The purpose of this retrospective study was to determine the value of contrast-enhanced helical CT for detecting and managing acute thoracic aortic injury (ATAI). Between June 1995 and February 2000, 1419 consecutive chest CT examinations were performed in the setting of major blunt trauma. The following CT findings were considered indicative of ATAI: intimal flap; pseudoaneurysm; contour irregularity; lumen abnormality; and extravasation of contrast material. On the basis of these direct findings no further diagnostic investigations were performed. Isolated mediastinal hematoma on CT scans was considered an indirect sign of ATAI: In these cases, thoracic aortography was performed even if CT indicated normal aorta. Seventy-seven patients had abnormal CT scans: Among the 23 patients with direct CT signs, acute thoracic aortic injuries was confirmed at thoracotomy in 21. Two false-positive cases were observed. The 54 remaining patients had isolated mediastinal hematoma without aortic injuries at CT and corresponding negative angiograms. The 1342 patients with negative CT scans were included in the 8-month follow-up program and did not show any adverse sequela based on clinical and radiographic criteria. Contrast-enhanced helical CT has a critical role in the exclusion of thoracic aortic injuries in patient with major blunt chest trauma and prevents unnecessary thoracic aortography. Direct CT signs of ATAI do not require further diagnostic investigations to confirm the diagnosis: Isolated aortic bands or contour vessel abnormalities should be first considered as possible artifacts or related to non-traumatic etiologies especially when mediastinal hematoma is absent. In cases of isolated mediastinal hematoma other possible sources of bleeding should be considered before directing patients to thoracic aortography. (orig.)

Lesion detection performance: comparative analysis of low-dose CT data of the chest on two hybrid imaging systems.

Science.gov (United States)

Jessop, Maryam; Thompson, John D; Coward, Joanne; Sanderud, Audun; Jorge, José; de Groot, Martijn; Lança, Luís; Hogg, Peter

2015-03-01

Incidental findings on low-dose CT images obtained during hybrid imaging are an increasing phenomenon as CT technology advances. Understanding the diagnostic value of incidental findings along with the technical limitations is important when reporting image results and recommending follow-up, which may result in an additional radiation dose from further diagnostic imaging and an increase in patient anxiety. This study assessed lesions incidentally detected on CT images acquired for attenuation correction on two SPECT/CT systems. An anthropomorphic chest phantom containing simulated lesions of varying size and density was imaged on an Infinia Hawkeye 4 and a Symbia T6 using the low-dose CT settings applied for attenuation correction acquisitions in myocardial perfusion imaging. Twenty-two interpreters assessed 46 images from each SPECT/CT system (15 normal images and 31 abnormal images; 41 lesions). Data were evaluated using a jackknife alternative free-response receiver-operating-characteristic analysis (JAFROC). JAFROC analysis showed a significant difference (P detection, with the figures of merit being 0.599 (95% confidence interval, 0.568, 0.631) and 0.810 (95% confidence interval, 0.781, 0.839) for the Infinia Hawkeye 4 and Symbia T6, respectively. Lesion detection on the Infinia Hawkeye 4 was generally limited to larger, higher-density lesions. The Symbia T6 allowed improved detection rates for midsized lesions and some lower-density lesions. However, interpreters struggled to detect small (5 mm) lesions on both image sets, irrespective of density. Lesion detection is more reliable on low-dose CT images from the Symbia T6 than from the Infinia Hawkeye 4. This phantom-based study gives an indication of potential lesion detection in the clinical context as shown by two commonly used SPECT/CT systems, which may assist the clinician in determining whether further diagnostic imaging is justified. © 2015 by the Society of Nuclear Medicine and Molecular Imaging

Ultrasound and supine chest radiograph in road traffic accident patients: a reliable and convenient way to diagnose pleural effusion

International Nuclear Information System (INIS)

Mumtaz, U.; Zahur, Z.; Raza, M.A.

2017-01-01

Background: Portable bed side ultrasound and supine chest radiograph of 80 traumatic patients excluding very clinically unstable patients who subsequently underwent CT scan chest was done for traumatic effusion showing that ultrasound had a higher sensitivity than CXR, 88.23% and 77.94%, respectively, and a similar specificity of 100% and 100%, respectively. Objective of the study is to compare the diagnostic accuracy of high resolution ultrasound and supine chest x-ray in detection of pleural effusion in road traffic accident patients keeping plain CT chest as gold standard. Methods: This study was conducted in PIMS and PAEC General Hospital, Islamabad from 1st January to 15th December 2015. The current study examined total of 80 trauma (blunt and penetrating) patients coming to emergency departments of both hospitals specifically those who had road traffic accident history. Their portable bed side ultrasound and supine chest radiograph were performed for assessing pleural effusion and subsequently CT scan chest was done for confirmation as it's a gold standard. Results: Using CT findings as gold standard the sensitivity, specificity, positive predictive value and negative predictive value was assessed for both ultrasonography and chest radiography and found to be 88.23%,100%, 100%, 40% and 77.94%, 100%, 100%, 55.55% respectively with diagnostic accuracy of ultrasound 90% as compared to 81.25% for supine chest x-rays when compared with gold standard. Conclusion: Ultrasound and chest x-ray can be used as a useful and suitable adjunct to CT in road traffic accident patients as these are easily available, non-invasive, no contrast required, can be performed on bed side and carries no or little radiation risk. (author)

Reconstruction of the radiation-damaged chest wall

International Nuclear Information System (INIS)

Arnold, P.G.; Pairolero, P.C.

1989-01-01

In the patient with a radiation ulcer of the chest wall, the first question is whether the lesion contains persistent or recurrent cancer. It is also important to determine whether any other local problems such as mediastinal abscess may interfere with the reconstruction. Whether or not cancer is present, all nonviable tissue must be removed. If cancer is not present, and a partial thickness of the chest remains, the authors prefer transposition of the greater omentum for repair. If cancer is present, the physiologic defect resulting from cancer resection and wound debridement is far more severe, and a muscle or musculocutaneous flap usually is appropriate. The pectoralis major, latissimus dorsi, external oblique, rectus abdominis, and trapezius muscles have been utilized; the authors most often use the pectoralis or latissimus muscles. 27 references

The influence of upper limb position on the effect of a contrast agent in chest CT enhancement

International Nuclear Information System (INIS)

Feng, Shi-Ting; Wang, Meng; Gao, Zhenhua; Tan, Guosheng; Cai, Huasong; Hu, Xiaoshu; Yang, Jianyong; Li, Zi-Ping

2013-01-01

Purpose: To compare the influence of two different upper limb positions on contrast agent effects in chest CT enhancement. Materials and methods: In 142 patients undergoing contrast-enhanced CT chest scanning, an indwelling venous catheter was placed in the right hand and iodinated contrast agent was injected through a high-pressure single syringe pump. The patients were divided into three age groups (<40 years; 40–60 years; and >60 years) and randomly assigned to one of two upper limb position groups: (1) supine position, both upper limbs extended and raised above head in the same horizontal plane as the body; and (2) supine position, both upper limbs raised and crossed on the forehead, with the right arm on top. Differences in mean CT values on the two sides of the thoracic inlet along the right subclavian vein were used to evaluate the effects of the contrast agent. Results: Although contrast agent effects were not significantly different among the three age groups with either limb position, there was a significant difference between patients adopting the second limb positions (Chi-square value was 5.936, P < 0.05). An excellent or good contrast agent effect was observed in 63.08% of patients assuming the first limb position, as compared with 81.69% assuming the second position. Conclusion: For contrast-enhanced CT chest scans, use of the second limb position can reduce retention of the contrast agent in the right axillary vein and the right subclavian vein outside the thorax, increase contrast agent utilization, and decrease artifacts caused by high-density, local retention of the contrast agent

Diagnostic imaging in polytrauma: comparison of radiation exposure from whole-body MSCT and conventional radiography with organ-specific CT; Radiologische Bildgebung beim Polytrauma: Dosisvergleich von Ganzkoerper-MSCT und konventionellem Roentgen mit organspezifischer CT

Energy Technology Data Exchange (ETDEWEB)

Wedegaertner, U.; Lorenzen, M.; Weber, C.; Adam, G. [Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie, Universitaetsklinikum Hamburg-Eppendorf (Germany); Nagel, H.D. [Philips Medizin Systeme GmbH, Hamburg (Germany)

2004-07-01

Purpose: To compare the radiation dose of whole-body multislice CT (MSCT) and conventional radiography with organ-specific CT in polytrauma. Materials and Methods: The whole-body MSCT encompassing brain, neck and midface, chest, abdomen and pelvis was performed on a Somatom Volume Zoom (Siemens). Conventional radiography consisted of chest and cervical, thoracic and lumbar spine in two views as well as pelvis. Polymat, Siemens. Three combinations of organ specific CT were chosen: CT examination of (1) head and cervical spine, (2) head, cervical spine and chest, (3) head, cervical spine and abdomen. The effective doses of whole-body MSCT and conventional radiography with organ-specific CT were calculated. Results: Effective doses were 20 mSv for whole-body MSCT, 2 mSv for conventional x-ray, and 5 mSv for combination (1), 8 mSv for combination (2) and (3) 16 mSv for combination (3) of the organ-specific CT. The ratio of radiation dose between whole-body MSCT and radiography was 10: 1. This ratio was reduced to 3: 1, 2: 1 and 1: 1 when a combination of radiography and CT was performed. Conclusions: Whole-body MSCT in polytrauma compared to conventional radiography with organ-specific CT induces a threefold increased dose in unfavorable situations and no increased dose in favorable situations. Nevertheless, routine use of whole-body MSCT should be critically evaluated and should be adapted to the clinical benefit. (orig.) [German] Ziel: Dosisvergleich von Ganzkoerper-MSCT und konventioneller Basisdiagnostik mit organspezifischen Ct-Untersuchungen beim Polytrauma. Material und Methoden: Die Ganzkoerper-MSCT-Untersuchung von Schaedel, Mittelgesicht, HWS sowie Thorax, Abdomen und Becken erfolgte an einem Somatom-Volume-Zoom (Siemens). Die konventionelle Bildgebung, bestehend aus Thorax, Becken, HWS, BWS und LWs, wurde an einem Siemens-Polymat durchgefuehrt. Fuer die organspezifischen CT-Untersuchungen wurden 3 Kombinationen ausgewaehlt: (1) CCT + HWS, (2) CCT + HWS

Usefulness of preoperative chest multidetector CT for evaluation of breast cancer: comparison with breast MRI

International Nuclear Information System (INIS)

Chang, Yun Woo; Kim, Dong Hun; Lee, Min Hyuk

2005-01-01

To evaluate the efficacy of chest multidetector-row helical computed tomography (MDCT) in detecting breast cancer in preoperative metastasis work-ups and to assess the accuracy of MDCT compared with magnetic resonance imaging (MRI). MDCT were performed on 69 consecutive patients with 94 lesions of histologically proven breast cancer. Retrospectively, two radiologists performed a blind review of the MDCT images for margin, shape, mass enhancement pattern and the enhancing distribution of non-mass lesions with consensus. CT attenuation values were measured in the average HU on pre-enhancing and enhanced CT in gland, fat, muscle, and in masses with the largest region of interest (ROI). MDCT finding were analyzed and compared with breast MRI. Of the 91 breast lesions detected on MDCT, 64 were mass lesions and 24 were non-mass lesions on enhancement, 86 lesions were malignant and 5 were benign. Three pathologically proven malignant masses were not detected on MDCT. Positive predictive value, false positive rate and false negative rate were 94.5%, 5.3%, 3.2% respectively. The highly predictive features for malignancy were a spiculated or irregular margin, an irregular of round shape, and a heterogeneously or rim enhanced mass. Another highly predictive feature for malignancy was linear or segmentally distributed enhancing non-mass lesions. The CT values of masses in pre-enhanced scans were 38.6 ± 7.9 HU; these values increased to 110.9 ± 26.6 HU after contrast injection (90 sec). The attenuation values from enhancing CT of malignant lesions were significantly higher than those of non-enhancing lesions. The depiction of enhancing masses on MDCT compared with MR imaging were 88.6%. The extension of malignancy were equally well correlated MDCT with MR imaging. The diagnostic value of chest MDCT for preoperative staging is comparable with MR imaging for the detection and extension of lesions. Therefore, chest MDCT of breast cancer can add to the information obtained from

Trauma of the chest

International Nuclear Information System (INIS)

Reuter, M.

1996-01-01

This paper describes the typical radiologic findings in chest trauma, and the value of conventional radiography, CT, MRI, and aortography is discussed. Conventional radiography rather than cross-sectional imaging is the mainstay in diagnosing thoracic trauma. During the critical phase with often concomitant shock, pelvic and spinal injuries tailored raiographic views or even upright chest radiographs are impractical. The severely traumatized patient is usually radiographed in the supine position and suboptimal roentgenograms may have to be accepted for several reasons. It is well documented that many abnormalities detected on CT were not apparent on conventional radiographs, but CT is reserved for hemodynamical stable patients. Nevertheless certain situations like aortic rupture require further evaluation by CT and aortography. (orig./MG)

Estimating cancer risks to adults undergoing body CT examinations

International Nuclear Information System (INIS)

Huda, W.; He, W.

2012-01-01

The purpose of the study is to estimate cancer risks from the amount of radiation used to perform body computed tomography (CT) examination. The ImPACT CT Patient Dosimetry Calculator was used to compute values of organ doses for adult body CT examinations. The radiation used to perform each examination was quantified by the dose-length product (DLP). Patient organ doses were converted into corresponding age and sex dependent cancer risks using data from BEIR VII. Results are presented for cancer risks per unit DLP and unit effective dose for 11 sensitive organs, as well as estimates of the contribution from 'other organs'. For patients who differ from a standard sized adult, correction factors based on the patient weight and antero-posterior dimension are provided to adjust organ doses and the corresponding risks. At constant incident radiation intensity, for CT examinations that include the chest, risks for females are markedly higher than those for males, whereas for examinations that include the pelvis, risks in males were slightly higher than those in females. In abdominal CT scans, risks for males and female patients are very similar. For abdominal CT scans, increasing the patient age from 20 to 80 resulted in a reduction in patient risks of nearly a factor of 5. The average cancer risk for chest/abdomen/pelvis CT examinations was ∼26 % higher than the cancer risk caused by 'sensitive organs'. Doses and radiation risks in 80 kg adults were ∼10 % lower than those in 70 kg patients. Cancer risks in body CT can be estimated from the examination DLP by accounting for sex, age, as well as patient physical characteristics. (authors)

Development of newborn chest phantom for dosimetric study in computed tomography

Energy Technology Data Exchange (ETDEWEB)

Aburjaile, W.N.; Lima, L.T.A.; Mourao, A.P., E-mail: wadia.namen@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Centro Federal de Educação Tecnológica de Minas Gerais (CEFET-MG), Belo Horizonte, MG (Brazil). Centro de Engenharia Biomédica

2017-11-01

Computed Tomography (CT) is a radiodiagnostic technique that allows evaluating the patient internal structures. In the last ten years, this technique has shown a high growth due to clinical cases of medical emergencies, neoplasm and pediatric traumas. The use dissemination of this technique has a significant increase in the patient dose. CT equipment installed in radiodiagnostic services present technological variations in the speed of acquisition or in the protocols used to obtain sectional images. The dose deposited in pediatric patients is directly related to energy retained during the exposure process to ionizing radiation, and radiation future effects is related with stochastic risks due to tissue radiosensitivity allied to the life expectancy of the child. The risk associated with a radiological examination can be considered quite low compared to the natural risk. However, any additional risk, no matter how small, is unacceptable if it does not benefit the patient. The knowledge of dose distribution is important when considering the variation of the acquisition parameters in order to reduce the dose. The objective of this work is to develop a newborn chest phantom for realize a comparative dosimetric study with the an adult standard phantom in order to evaluate the dose variation in CT scans. In this work, a cylindrical phantom, representing an adult chest made of polymethylmethacrylate (PMMA), was used and a new born chest phantom with a shape oblong was developed based on the dimensions of a typical newborn. In a GE CT scanner, Discovery model, with 64 channels, the central slice of the phantoms were irradiated successively in order to obtain dose measurements using an ionizing pencil camera. The radiological service chest protocol using a voltage of 120 kV was used for scanning 10 cm of the central area of the adult and newborn phantoms, in helical mode. The measurements have allowed to obtain the volumetric dose index values for the adult and newborn

Radiation Load of Children by Chest Radiodiagnostic Measurements

International Nuclear Information System (INIS)

Nikodemova, D.; Vladar, M.; Ranogajec-Komor, M.; Horvathova, M.

1998-01-01

Radiodiagnostic examinations of children present particular importance from the radiation hygiene point of view. The estimation of the radiation load of pediatric patient is not easy, because of the lack of information about organ weighting factors for various ages of patients, as well as due to the differences in applied X-ray examination parameters. In the district of Slovak Republic, in which also the working Nuclear Power Plant Jaslovske Bohunice is included, efforts were done to estimate the radiation load of children to 15 years by chest radiodiagnostic examinations. The data of entrance surface doses were collected using measurements with TLD for 100 patients divided in 5 age categories at six radiodiagnostic departments. The calculations of the total absorbed dose were performed using the measured ESD values (entrance surface dose in mGy) integrated over the X-ray beam area, the conversion factors between the imparted energy and the dose-area product and the known irradiation parameters (kV, HVL, mass, etc.). The analysis of the obtained absorbed doses (E a ) as a function of age for chest PA radiodiagnostic examinations has shown, that the investigated Slovak radiodiagnostic centres use rather lower voltage techniques and the entrance surface doses are much higher than the proposed value of European Communities. (author)

Optimizing Radiation Doses for Computed Tomography Across Institutions: Dose Auditing and Best Practices.

Science.gov (United States)

Demb, Joshua; Chu, Philip; Nelson, Thomas; Hall, David; Seibert, Anthony; Lamba, Ramit; Boone, John; Krishnam, Mayil; Cagnon, Christopher; Bostani, Maryam; Gould, Robert; Miglioretti, Diana; Smith-Bindman, Rebecca

2017-06-01

Radiation doses for computed tomography (CT) vary substantially across institutions. To assess the impact of institutional-level audit and collaborative efforts to share best practices on CT radiation doses across 5 University of California (UC) medical centers. In this before/after interventional study, we prospectively collected radiation dose metrics on all diagnostic CT examinations performed between October 1, 2013, and December 31, 2014, at 5 medical centers. Using data from January to March (baseline), we created audit reports detailing the distribution of radiation dose metrics for chest, abdomen, and head CT scans. In April, we shared reports with the medical centers and invited radiology professionals from the centers to a 1.5-day in-person meeting to review reports and share best practices. We calculated changes in mean effective dose 12 weeks before and after the audits and meeting, excluding a 12-week implementation period when medical centers could make changes. We compared proportions of examinations exceeding previously published benchmarks at baseline and following the audit and meeting, and calculated changes in proportion of examinations exceeding benchmarks. Of 158 274 diagnostic CT scans performed in the study period, 29 594 CT scans were performed in the 3 months before and 32 839 CT scans were performed 12 to 24 weeks after the audit and meeting. Reductions in mean effective dose were considerable for chest and abdomen. Mean effective dose for chest CT decreased from 13.2 to 10.7 mSv (18.9% reduction; 95% CI, 18.0%-19.8%). Reductions at individual medical centers ranged from 3.8% to 23.5%. The mean effective dose for abdominal CT decreased from 20.0 to 15.0 mSv (25.0% reduction; 95% CI, 24.3%-25.8%). Reductions at individual medical centers ranged from 10.8% to 34.7%. The number of CT scans that had an effective dose measurement that exceeded benchmarks was reduced considerably by 48% and 54% for chest and abdomen, respectively. After

Assessment of noise reduction potential and image quality improvement of a new generation adaptive statistical iterative reconstruction (ASIR-V) in chest CT.

Science.gov (United States)

Tang, Hui; Yu, Nan; Jia, Yongjun; Yu, Yong; Duan, Haifeng; Han, Dong; Ma, Guangming; Ren, Chenglong; He, Taiping

2018-01-01

To evaluate the image quality improvement and noise reduction in routine dose, non-enhanced chest CT imaging by using a new generation adaptive statistical iterative reconstruction (ASIR-V) in comparison with ASIR algorithm. 30 patients who underwent routine dose, non-enhanced chest CT using GE Discovery CT750HU (GE Healthcare, Waukesha, WI) were included. The scan parameters included tube voltage of 120 kVp, automatic tube current modulation to obtain a noise index of 14HU, rotation speed of 0.6 s, pitch of 1.375:1 and slice thickness of 5 mm. After scanning, all scans were reconstructed with the recommended level of 40%ASIR for comparison purpose and different percentages of ASIR-V from 10% to 100% in a 10% increment. The CT attenuation values and SD of the subcutaneous fat, back muscle and descending aorta were measured at the level of tracheal carina of all reconstructed images. The signal-to-noise ratio (SNR) was calculated with SD representing image noise. The subjective image quality was independently evaluated by two experienced radiologists. For all ASIR-V images, the objective image noise (SD) of fat, muscle and aorta decreased and SNR increased along with increasing ASIR-V percentage. The SD of 30% ASIR-V to 100% ASIR-V was significantly lower than that of 40% ASIR (p ASIR-V reconstructions had good diagnostic acceptability. However, the 50% ASIR-V to 70% ASIR-V series showed significantly superior visibility of small structures when compared with the 40% ASIR and ASIR-V of other percentages (p ASIR-V was the best series of all ASIR-V images, with a highest subjective image quality. The image sharpness was significantly decreased in images reconstructed by 80% ASIR-V and higher. In routine dose, non-enhanced chest CT, ASIR-V shows greater potential in reducing image noise and artefacts and maintaining image sharpness when compared to the recommended level of 40%ASIR algorithm. Combining both the objective and subjective evaluation of images, non

Radiation dose from multidetector CT studies in children: results from the first Italian nationwide survey

Energy Technology Data Exchange (ETDEWEB)

Granata, Claudio [IRCCS Istituto Giannina Gaslini, Department of Radiology, Genoa (Italy); Origgi, Daniela; Palorini, Federica [Istituto Europeo di Oncologia, Department of Medical Physics, Milan (Italy); Matranga, Domenica [University of Palermo, Department of Sciences for Health Promotion and Mother and Child Care ' ' G. D' Alessandro' ' , Palermo (Italy); Salerno, Sergio [University of Palermo, Department of Medical and Forensic Biopathology and Biotechnologies, Section of Radiology, Palermo (Italy)

2015-05-01

Multidetector CT (MDCT) scanners have contributed to the widespread use of CT in paediatric imaging. However, concerns are raised for the associated radiation exposure. Very few surveys on radiation exposure from MDCT studies in children are available. The aim of this study was to outline the status of radiation exposure in children from MDCT practice in Italy. In this retrospective multicentre study we asked Italian radiology units with an MDCT scanner with at least 16 slices to provide dosimetric and acquisition parameters of CT examinations in three age groups (1-5, 6-10, 11-15 years) for studies of head, chest and abdomen. The dosimetric results were reported in terms of third-quartile volumetric CT dose index (CTDI{sub vol}) (mGy), size-specific dose estimate (SSDE) (mGy), dose length product (DLP) (mGy cm), and total DLP for multiphase studies. These results were compared with paediatric European and adult Italian published data. A multivariate analysis assessed the association of CTDI{sub vol} with patient characteristics and scanning modalities. We collected data from 993 MDCT examinations performed at 25 centres. For age groups 1-5 years, 6-10 years and 11-15 years, the CTDI{sub vol}, DLP and total DLP values were statistically significantly below the values observed in our analogous national survey in adults, although the difference decreased with increasing age. CTDI{sub vol} variability among centres was statistically significant (variance = 0.07; 95% confidence interval = 0.03-0.16; P < 0.001). This study reviewed practice in Italian centres performing paediatric imaging with MDCT scanners. The variability of doses among centres suggests that the use of standardised CT protocols should be encouraged. (orig.)

Volume-monitored chest CT: a simplified method for obtaining motion-free images near full inspiratory and end expiratory lung volumes

Energy Technology Data Exchange (ETDEWEB)

Mueller, Kathryn S. [The Ohio State University College of Medicine, Columbus, OH (United States); Long, Frederick R. [Nationwide Children' s Hospital, The Children' s Radiological Institute, Columbus, OH (United States); Flucke, Robert L. [Nationwide Children' s Hospital, Department of Pulmonary Medicine, Columbus, OH (United States); Castile, Robert G. [The Research Institute at Nationwide Children' s Hospital, Center for Perinatal Research, Columbus, OH (United States)

2010-10-15

Lung inflation and respiratory motion during chest CT affect diagnostic accuracy and reproducibility. To describe a simple volume-monitored (VM) method for performing reproducible, motion-free full inspiratory and end expiratory chest CT examinations in children. Fifty-two children with cystic fibrosis (mean age 8.8 {+-} 2.2 years) underwent pulmonary function tests and inspiratory and expiratory VM-CT scans (1.25-mm slices, 80-120 kVp, 16-40 mAs) according to an IRB-approved protocol. The VM-CT technique utilizes instruction from a respiratory therapist, a portable spirometer and real-time documentation of lung volume on a computer. CT image quality was evaluated for achievement of targeted lung-volume levels and for respiratory motion. Children achieved 95% of vital capacity during full inspiratory imaging. For end expiratory scans, 92% were at or below the child's end expiratory level. Two expiratory exams were judged to be at suboptimal volumes. Two inspiratory (4%) and three expiratory (6%) exams showed respiratory motion. Overall, 94% of scans were performed at optimal volumes without respiratory motion. The VM-CT technique is a simple, feasible method in children as young as 4 years to achieve reproducible high-quality full inspiratory and end expiratory lung CT images. (orig.)

A case of sarcoma of the chest wall after radiation therapy for breast cancer

International Nuclear Information System (INIS)

Izumi, Junko; Nishi, Tsunehiro; Fukuuchi, Atsushi; Takanashi, Riichiro

1998-01-01

A case of radiation-induced sarcoma of the chest wall after radiation therapy for breast cancer is reported. A 69-year-old woman underwent mastectomy with axillary lymph node dissection followed by linac therapy of 50 Gy delivered to the left axilla, left supraclavicular area, and parasternal area. During therapy for bone and liver metastases, a tumor was noted in the left chest wall 15 years after radiation therapy. Incisional biopsy was performed. Histological diagnosis was spindle cell sarcoma. Radiation-induced sarcoma was suspected because the tumor developed 15 years after radiation therapy within the same area. Radiation-induced sarcoma is a rare tumor, but radiation therapy following breast-conserving therapy is widely employed. It is important to be aware of the possibility of radiation-induced sarcoma. (author)

Occult pneumomediastinum in blunt chest trauma: clinical significance.

Science.gov (United States)

Rezende-Neto, J B; Hoffmann, J; Al Mahroos, M; Tien, H; Hsee, L C; Spencer Netto, F; Speers, V; Rizoli, S B

2010-01-01

Thoracic injuries are potentially responsible for 25% of all trauma deaths. Chest X-ray is commonly used to screen patients with chest injury. However, the use of computed tomography (CT) scan for primary screening is increasing, particularly for blunt trauma. CT scans are more sensitive than chest X-ray in detecting intra-thoracic abnormalities such as pneumothoraces and pneumomediastinums. Pneumomediastinum detected by chest X-ray or "overt pneumomediastinum", raises the concern of possible aerodigestive tract injuries. In contrast, there is scarce information on the clinical significance of pneumomediastinum diagnosed by CT scan only or "occult pneumomediastinum". Therefore we investigated the clinical consequences of occult pneumomediastinum in our blunt trauma population. A 2-year retrospective chart review of all blunt chest trauma patients with initial chest CT scan admitted to a level I trauma centre. Data extracted from the medical records include; demographics, occult, overt, or no pneumomediastinum, the presence of intra-thoracic aerodigestive tract injuries (trachea, bronchus, and/or esophagus), mechanism and severity of injury, endotracheal intubation, chest thoracostomy, operations and radiological reports by an attending radiologist. All patients with intra-thoracic aerodigestive tract injuries from 1994 to 2004 were also investigated. Of 897 patients who met the inclusion criteria 839 (93.5%) had no pneumomediastinum. Five patients (0.6%) had overt pneumomediastinum and 53 patients (5.9%) had occult pneumomediastinum. Patients with occult pneumomediastinum had significantly higher ISS and AIS chest (pchest thoracostomy tube was more common (ppneumothorax. None of the patients with occult pneumomediastinum had aerodigestive tract injuries (95%CI 0-0.06). Follow up CT scan of patients with occult pneumomediastinum showed complete resolution in all cases, in average 3 h after the initial exam. Occult pneumomediastinum occurred in approximately 6% of

[Radiation exposure of children in pediatric radiology. Part 5: organ doses in chest radiography].

Science.gov (United States)

Seidenbusch, M C; Schneider, K

2009-05-01

Reconstruction of organ doses of selected organs and tissues from radiographic settings and exposure data collected during chest X-ray examinations of children of various age groups performed in Dr. von Hauner's Kinderspital (children's hospital of the University of Munich, DvHK) between 1976 and 2007. The dosimetric data of all X-ray examinations performed since 1976 at DvHK were stored electronically in a database. After 30 years of data collection, the database now includes 305 107 radiological examinations (radiographs and fluoroscopies), especially 119 150 chest radiographs of all age groups. Reconstruction of organ doses in 40 organs and tissues in X-ray examinations of the chest was performed based on the conversion factor concept. The radiation exposure of organs in projection radiography is determined by the exact site of the organs relative to the edges of the X-ray field and the beam direction of X-rays. Optimal collimation in chest radiography can reduce the exposure of organs located at the periphery of the X-ray field, e. g. thyroid gland, stomach and partially the liver, by a factor of 2 to 3, while organs located in the center of the X-ray-field, e. g. thymus, breasts, lungs, esophagus and red bone marrow, are not affected by exact collimation. The high frequency of the roentgen examination of the chest in early age groups increases the collective radiation burden to radiosensitive organs. Therefore, radiation protection of the patient during chest radiographies remains of great importance.

Radiation dose-reduction strategies in thoracic CT.

Science.gov (United States)

Moser, J B; Sheard, S L; Edyvean, S; Vlahos, I

2017-05-01

Modern computed tomography (CT) machines have the capability to perform thoracic CT for a range of clinical indications at increasingly low radiation doses. This article reviews several factors, both technical and patient-related, that can affect radiation dose and discusses current dose-reduction methods relevant to thoracic imaging through a review of current techniques in CT acquisition and image reconstruction. The fine balance between low radiation dose and high image quality is considered throughout, with an emphasis on obtaining diagnostic quality imaging at the lowest achievable radiation dose. The risks of excessive radiation dose reduction are also considered. Inappropriately low dose may result in suboptimal or non-diagnostic imaging that may reduce diagnostic confidence, impair diagnosis, or result in repeat examinations incurring incremental ionising radiation exposure. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

CT coronary angiographic evaluation of suspected anginal chest pain.

Science.gov (United States)

Moss, Alastair J; Newby, David E

2016-02-15

Non-invasive imaging plays a critical role in the assessment of patients presenting with suspected angina chest pain. However, wide variations in practice across Europe and North America highlight the lack of consensus in selecting the appropriate first-line test for the investigation of coronary artery disease (CAD). CT coronary angiography (CTCA) has a high negative predictive value for excluding the presence of CAD. As such, it serves as a potential 'gatekeeper' to downstream testing by reducing the rate of inappropriate invasive coronary angiography. Two recent large multicentre randomised control trials have provided insights into whether CTCA can be incorporated into chest pain care pathways to improve risk stratification of CAD. They demonstrate that using CTCA enhances diagnostic certainty and improves the targeting of appropriate invasive investigations and therapeutic interventions. Importantly, reductions in cardiac death and non-fatal myocardial infarction appear to be attained through the more appropriate use of preventative therapy and coronary revascularisation when guided by CTCA. With this increasing portfolio of evidence, CTCA should be considered the non-invasive investigation of choice in the evaluation of patients with suspected angina pectoris due to coronary heart disease. NCT01149590, post-results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Digital tomosynthesis of the chest: A literature review

International Nuclear Information System (INIS)

Molk, N.; Seeram, E.

2015-01-01

Digital tomosynthesis is a relatively novel imaging modality using limited angle tomography to provide 3D imaging. The purpose of this review is to compare the sensitivity of digital tomosynthesis of the chest and plain film chest imaging in accurately identifying pulmonary nodules and to compare the effective dose between standard chest examinations using digital tomosynthesis and CT. A review of current literature has shown that small scale studies found digital tomosynthesis to be three times more effective in identifying pulmonary nodules compared to conventional radiography and at lower doses compared with routine chest CT examinations. This indicates that tomosynthesis could potentially be a beneficial imaging modality and could be used in a number of ways to detect and monitor pulmonary nodules for cancer. However with limited research, large-scale studies would need to be performed to confirm its benefits and identify where it is best used in the clinical setting. - Highlights: • The detection of pulmonary nodules is compared between tomosynthesis and plain film. • The effective dose of digital chest tomosynthesis and chest CT are compared. • The place of digital tomosynthesis of the chest in the clinical setting is explored. • Three times more pulmonary nodules are seen with tomosynthesis. • The effective dose of tomosynthesis is significantly lower than CT

Subpleural thoracic fat as defined with CT of the chest

International Nuclear Information System (INIS)

Anderson, D.J.; Glazer, H.S.; Molina, P.L.; Sagel, S.S.

1988-01-01

Consecutive computed tomographic (CT) examinations of the chest (n=202) were reviewed to determine the location, thickness, and extent of subpleural fat. Patient age, thickness of subcutaneous fat, and adjacent pleural or parenchymal abnormalities were recorded. Subpleural fat was most often identified in the paravertebral region (48%) and in the apices (23%). Fatty deposits anterolaterally were seen in seven individuals. Subpleural fat thickness ranged from 1 to 19 mm, except in the apex, where fat sometimes filled the space. A direct relationship between subcutaneous fat thickness and a higher incidence of subpleural fat was observed in the paravertebral region. Subpleural fat occurs commonly in the paravertebral regions but is unusual in other areas

Performance evaluation of 3-D enhancement filters for detection of lung cancer from 3-D chest X-ray CT images

International Nuclear Information System (INIS)

Shimizu, Akinobu; Hagai, Makoto; Toriwaki, Jun-ichiro; Hasegawa, Jun-ichi.

1995-01-01

This paper evaluates the performance of several three dimensional enhancement filters used in procedures for detecting lung cancer shadows from three dimensional (3D) chest X-ray CT images. Two dimensional enhancement filters such as Min-DD filter, Contrast filter and N-Quoit filter have been proposed for enhancing cancer shadows in conventional 2D X-ray images. In this paper, we extend each of these 2D filters to a 3D filter and evaluate its performance experimentally by using CT images with artificial and true lung cancer shadows. As a result, we find that these 3D filters are effective for determining the position of a lung cancer shadow in a 3D chest CT image, as compared with the simple procedure such as smoothing filter, and that the performance of these filters become lower in the hilar area due to the influence of the vessel shadows. (author)

Automated detection system for pulmonary emphysema on 3D chest CT images

Science.gov (United States)

Hara, Takeshi; Yamamoto, Akira; Zhou, Xiangrong; Iwano, Shingo; Itoh, Shigeki; Fujita, Hiroshi; Ishigaki, Takeo

2004-05-01

An automatic extraction of pulmonary emphysema area on 3-D chest CT images was performed using an adaptive thresholding technique. We proposed a method to estimate the ratio of the emphysema area to the whole lung volume. We employed 32 cases (15 normal and 17 abnormal) which had been already diagnosed by radiologists prior to the study. The ratio in all the normal cases was less than 0.02, and in abnormal cases, it ranged from 0.01 to 0.26. The effectiveness of our approach was confirmed through the results of the present study.

PET/CT-guided Interventions: Personnel Radiation Dose

Energy Technology Data Exchange (ETDEWEB)

Ryan, E. Ronan, E-mail: ronan@ronanryan.com; Thornton, Raymond; Sofocleous, Constantinos T.; Erinjeri, Joseph P. [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States); Hsu, Meier [Memorial Sloan-Kettering Cancer Center, Department of Epidemiology and Biostatistics (United States); Quinn, Brian; Dauer, Lawrence T. [Memorial Sloan-Kettering Cancer Center, Department of Medical Physics (United States); Solomon, Stephen B. [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States)

2013-08-01

PurposeTo quantify radiation exposure to the primary operator and staff during PET/CT-guided interventional procedures.MethodsIn this prospective study, 12 patients underwent PET/CT-guided interventions over a 6 month period. Radiation exposure was measured for the primary operator, the radiology technologist, and the nurse anesthetist by means of optically stimulated luminescence dosimeters. Radiation exposure was correlated with the procedure time and the use of in-room image guidance (CT fluoroscopy or ultrasound).ResultsThe median effective dose was 0.02 (range 0-0.13) mSv for the primary operator, 0.01 (range 0-0.05) mSv for the nurse anesthetist, and 0.02 (range 0-0.05) mSv for the radiology technologist. The median extremity dose equivalent for the operator was 0.05 (range 0-0.62) mSv. Radiation exposure correlated with procedure duration and with the use of in-room image guidance. The median operator effective dose for the procedure was 0.015 mSv when conventional biopsy mode CT was used, compared to 0.06 mSv for in-room image guidance, although this did not achieve statistical significance as a result of the small sample size (p = 0.06).ConclusionThe operator dose from PET/CT-guided procedures is not significantly different than typical doses from fluoroscopically guided procedures. The major determinant of radiation exposure to the operator from PET/CT-guided interventional procedures is time spent in close proximity to the patient.

Model-based iterative reconstruction in pediatric chest CT: assessment of image quality in a prospective study of children with cystic fibrosis

Energy Technology Data Exchange (ETDEWEB)

Mieville, Frederic A.; Bochud, Francois O.; Verdun, Francis R. [Lausanne University Hospital, Institute of Radiation Physics, Lausanne (Switzerland); Berteloot, Laureline; Brunelle, Francis [Necker Children' s Hospital of Paris and University of Paris Descartes, Department of Pediatric Radiology, Paris (France); Grandjean, Albane; Ayestaran, Paul [General Electric Medical Systems Europe, Paris (France); Gudinchet, Francois; Schmidt, Sabine [Lausanne University Hospital, Department of Radiology, Lausanne (Switzerland)

2013-03-15

The potential effects of ionizing radiation are of particular concern in children. The model-based iterative reconstruction VEO trademark is a technique commercialized to improve image quality and reduce noise compared with the filtered back-projection (FBP) method. To evaluate the potential of VEO trademark on diagnostic image quality and dose reduction in pediatric chest CT examinations. Twenty children (mean 11.4 years) with cystic fibrosis underwent either a standard CT or a moderately reduced-dose CT plus a minimum-dose CT performed at 100 kVp. Reduced-dose CT examinations consisted of two consecutive acquisitions: one moderately reduced-dose CT with increased noise index (NI = 70) and one minimum-dose CT at CTDI{sub vol} 0.14 mGy. Standard CTs were reconstructed using the FBP method while low-dose CTs were reconstructed using FBP and VEO. Two senior radiologists evaluated diagnostic image quality independently by scoring anatomical structures using a four-point scale (1 = excellent, 2 = clear, 3 = diminished, 4 = non-diagnostic). Standard deviation (SD) and signal-to-noise ratio (SNR) were also computed. At moderately reduced doses, VEO images had significantly lower SD (P < 0.001) and higher SNR (P < 0.05) in comparison to filtered back-projection images. Further improvements were obtained at minimum-dose CT. The best diagnostic image quality was obtained with VEO at minimum-dose CT for the small structures (subpleural vessels and lung fissures) (P < 0.001). The potential for dose reduction was dependent on the diagnostic task because of the modification of the image texture produced by this reconstruction. At minimum-dose CT, VEO enables important dose reduction depending on the clinical indication and makes visible certain small structures that were not perceptible with filtered back-projection. (orig.)

Quantification of pneumothorax volume on chest radiographs: comparison between the collins' and the axel's methods with three-dimensional CT as the standard of reference

International Nuclear Information System (INIS)

Lee, Chang Keun; Kim, Hyung Jin; Lee, Kyung Hee; Kim, Joung Taek; Kim, Kwang Ho; Suh, Chang Hae; Han, Heon

1999-01-01

The purpose of this study was twofold. In a preliminary study, we evaluated the accuracy of 3-D (three-dimensional) CT for the estimation of pneumothorax volume and for providing the optimal postprocessing method for clinical study. In the clinical study, we determined which of the two methods, Collins' and Axel's, was more accurate for the estimation of pneumothorax volume, as seen on chest radiographs, using 3-D CT as the standard of reference. In the preliminary study, 3-D CT was applied to phantoms and to four patients with pneumothorax using two different postprocessing methods, manual contour delineation and thresholding. In the clinical study, 3-D CT was performed in 13 patients with pneumothorax. For the purpose of evaluating conventional radiographs, a localizer scan was used for comparing the accuracy of Collins' method with that of Axel's method, with 3-D CT as the standard of reference. The preliminary study revealed that 3-D CT estimated pneumothorax volume with great accuracy and that manual contour delineation and thresholding measured volume equally well. Because of the shorter postprocessing time required with thresholding than with manual contour delineation (5 min versus 30 min), the former was used during clinical study. The results of this indicated close correlation between the measurements obtained using Collins' method on chest radiographs and those obtained by 3-D CT(r=0.95, p 0.05). 3-D CT can estimate pneumothorax volume with great accuracy. Collins' method is superior to Axel's method for the quantification of pneumothorax volume as seen on chest radiographs

Screening for lung cancer with digital chest radiography: sensitivity and number of secondary work-up CT examinations

NARCIS (Netherlands)

de Hoop, Bartjan; Schaefer-Prokop, Cornelia; Gietema, Hester A.; de Jong, Pim A.; van Ginneken, Bram; van Klaveren, Rob J.; Prokop, Mathias

2010-01-01

To estimate the performance of digital chest radiography for detection of lung cancer. The study had ethics committee approval, and a nested case-control design was used and included 55 patients with lung cancer detected at computed tomography (CT) and confirmed with histologic examination and a

Proton MRI in the evaluation of pulmonary sarcoidosis: Comparison to chest CT

International Nuclear Information System (INIS)

Chung, Jonathan H.; Little, Brent P.; Forssen, Anna V.; Yong, Jin; Nambu, Atsushi; Kazlouski, Demitry; Puderbach, Michael; Biederer, Juergen; Lynch, David A.

2013-01-01

Purpose: The purpose of this study was to determine the feasibility of proton MRI of the lung in sarcoidosis patients and the agreement between the imaging appearance of pulmonary sarcoidosis on MRI and CT. Materials and methods: Chest CT scans and dedicated pulmonary MRI scans (including HASTE, VIBE, and TrueFISP sequences) were performed within 90 days of each other in 29 patients. The scans were scored for gross parenchymal opacification, reticulation, nodules, and masses using a 3-point lobar scale. Total and subset scores for corresponding MRI and CT scans were compared using the Spearman correlation test, Bland–Altman plots, and Cohen's quadratic-weighted kappa analysis. MRI scores were compared to CT by lobe and disease category, using percentage agreement, Spearman rank correlation, and Cohen's quadratic-weighted kappa. Results: The mean (±s.d.) time between MRI and CT scans was 33 ± 32 days. There was substantial correlation and agreement between total disease scoring on MRI and CT with a Spearman correlation coefficient of 0.774 (p < 0.0001) and a Cohen's weighted kappa score of 0.646. Correlation and agreement were highest for gross parenchymal opacification (0.695, 0.528) and reticulation (0.609, 0.445), and lowest in the setting of nodules (0.501, 0.305). Agreement testing was not performed for mass scores due to low prevalence. Upper lobe scoring on MRI and CT demonstrated greater agreement compared to the lower lobes (average difference in Cohen's weighted kappa score of 0.112). Conclusion: There is substantial correlation and agreement between MRI and CT in the scoring of pulmonary sarcoidosis, though MRI evaluation in the upper lobes may be more accurate than in the lower lobes

Chest wall deformity and respiratory distress in a 17-year-old patient with achondroplasia: CT and MRI evaluation

Energy Technology Data Exchange (ETDEWEB)

Herman, T.E.; Siegel, M.J.; McAlister, W.H. (Washington Univ. School of Medicine, St. Louis, MO (United States). Mallinckrodt Inst. of Radiology)

1992-06-01

A marked thoracic deformity associated with intrathoracic tracheal narrowing was seen in a 17-year old with achondroplasia and dyspnea. The role of chest deformity and its evaluation by CT and MRI in achondroplastic patients with respiratory symptoms are considered. (orig.).

Chest wall deformity and respiratory distress in a 17-year-old patient with achondroplasia: CT and MRI evaluation

International Nuclear Information System (INIS)

Herman, T.E.; Siegel, M.J.; McAlister, W.H.

1992-01-01

A marked thoracic deformity associated with intrathoracic tracheal narrowing was seen in a 17-year old with achondroplasia and dyspnea. The role of chest deformity and its evaluation by CT and MRI in achondroplastic patients with respiratory symptoms are considered. (orig.)

Unrequested information from routine diagnostic chest CT predicts future cardiovascular events

International Nuclear Information System (INIS)

Jacobs, Peter C.; Gondrie, Martijn J.; Grobbee, Diederick E.; Graaf, Yolanda van der; Mali, Willem P.; Oen, Ayke L.; Prokop, Mathias

2011-01-01

An increase in the number of CT investigations will likely result in a an increase in unrequested information. Clinical relevance of these findings is unknown. This is the first follow-up study to investigate the prognostic relevance of subclinical coronary (CAC) and aortic calcification (TAC) as contained in routine diagnostic chest CT in a clinical care population. The follow-up of 10,410 subjects (>40 years) from a multicentre, clinical care-based cohort of patients included 240 fatal to 275 non-fatal cardiovascular disease (CVD) events (mean follow-up 17.8 months). Patients with a history of CVD were excluded. Coronary (0-12) and aortic calcification (0-8) were semi-quantitatively scored. We used Cox proportional-hazard models to compute hazard ratios to predict CVD events. CAC and TAC were significantly and independently predictive of CVD events. Compared with subjects with no calcium, the adjusted risk of a CVD event was 3.7 times higher (95% CI, 2.7-5.2) among patients with severe coronary calcification (CAC score ≥6) and 2.7 times higher (95% CI, 2.0-3.7) among patients with severe aortic calcification (TAC score ≥5). Subclinical vascular calcification on CT is a strong predictor of incident CVD events in a routine clinical care population. (orig.)

CT manifestations of radiation-induced change in chest tissue

International Nuclear Information System (INIS)

Pagani, J.J.; Libshitz, H.I.

1982-01-01

The computed tomographic appearance of acute and chronic radiation change in the thorax is described. Acute radiation pneumonitis demonstrates patchy, confluent regions of increased pulmonary attenuation. Chronic changes include soft tissue density fibrotic changes that blend smoothly with the pleural surfaces and adjacent mediastinal structures. Also seen are bronchiectatic changes and distortion of normal intrathoracic anatomic relationships. Both the acute and chronic changes usually make linear lateral margins with adjacent aerated lung. Development of a discrete mass or focal cavitation after the radiation changes have become stable is suspect for recurrent tumor or infection

Pulmonary tuberculosis mimicking lung cancer on radiological findings: Evaluation of chest CT findings in pathologically proven 76 patients

International Nuclear Information System (INIS)

Lee, Daun; Shin, Sang Soo; Kim, Yun Hyeon; Kim, Hyoung Ook; Seon, Hyun Ju; Kang, Heoung Keun

2012-01-01

To evaluate chest CT features of pulmonary tuberculosis mimicking lung malignancy. We retrospectively reviewed chest CT findings for 76 consecutive patients (21-84 years, average: 63 years; M : F = 30 : 46) who underwent an invasive diagnostic procedure under the suspicion of lung cancer and were pathologically diagnosed as pulmonary tuberculosis by bronchoscopic biopsy (n = 49), transthoracic needle biopsy (n = 17), and surgical resection (n = 10). We categorized the chest CT patterns of those lesions as follows: bronchial narrowing or obstruction without a central mass like lesion (pattern 1), central mass-like lesion with distal atelectasis or obstructive pneumonia (pattern 2), peripheral nodule or mass including mass-like consolidation (pattern 3), and cavitary lesion (pattern 4). CT findings were reviewed with respect to the patterns and the locations of the lesions, parenchymal abnormalities adjacent to the lesions, the size, the border and pattern of enhancement for the peripheral nodule or mass and the thickness of the cavitary wall in the cavitary lesion. We also evaluated the abnormalities regarding the lymph node and pleura. Pattern 1 was the most common finding (n = 34), followed by pattern 3 (n = 23), pattern 2 (n = 11) and finally, pattern 4 (n = 8). The most frequently involving site in pattern 1 and 2 was the right middle lobe (n = 14/45). However, in pattern 3 and 4, the superior segment of right lower lobe (n = 5/31) was most frequently involved. Ill-defined small nodules and/or larger confluent nodules were found in the adjacent lung and at the other segment of the lung in 31 patients (40.8%). Enlarged lymph nodes were most commonly detected in the right paratracheal area (n = 9/18). Pleural effusion was demonstrated in 10 patients. On the CT, pulmonary tuberculosis mimicking lung cancer most commonly presented with bronchial narrowing or obstruction without a central mass-like lesion, which resulted in distal atelectasis and obstructive

Pulmonary tuberculosis mimicking lung cancer on radiological findings: Evaluation of chest CT findings in pathologically proven 76 patients

Energy Technology Data Exchange (ETDEWEB)