Quantitative analysis of emphysema and airway measurements according to iterative reconstruction algorithms: comparison of filtered back projection, adaptive statistical iterative reconstruction and model-based iterative reconstruction.

OBJECTIVES: To evaluate filtered back projection (FBP) and two iterative reconstruction (IR) algorithms and their effects on the quantitative analysis of lung parenchyma and airway measurements on computed tomography (CT) images. METHODS: Low-dose chest CT obtained in 281 adult patients were reconstructed using three algorithms: FBP, adaptive statistical IR (ASIR) and model-based IR (MBIR). Measurements of each dataset were compared: total lung volume, emphysema index (EI), airway measurements of the lumen and wall area as well as average wall thickness. Accuracy of airway measurements of each algorithm was also evaluated using an airway phantom. RESULTS: EI using a threshold of -950 HU was significantly different among the three algorithms in decreasing order of FBP (2.30 %), ASIR (1.49 %) and MBIR (1.20 %) (P < 0.01). Wall thickness was also significantly different among the three algorithms with FBP (2.09 mm) demonstrating thicker walls than ASIR (2.00 mm) and MBIR (1.88 mm) (P < 0.01). Airway phantom analysis revealed that MBIR showed the most accurate value for airway measurements. CONCLUSION: The three algorithms presented different EIs and wall thicknesses, decreasing in the order of FBP, ASIR and MBIR. Thus, care should be taken in selecting the appropriate IR algorithm on quantitative analysis of the lung. KEY POINTS: • Computed tomography is increasingly used to provide objective measurements of intra-thoracic structures. • Iterative reconstruction algorithms can affect quantitative measurements of lung and airways. • Care should be taken in selecting reconstruction algorithms in longitudinal analysis. • Model-based iterative reconstruction seems to provide the most accurate airway measurements.

Does antiplatelet therapy increase the risk of hemoptysis during percutaneous transthoracic needle biopsy of a pulmonary lesion?

OBJECTIVE: The purpose of this article is to evaluate whether antiplatelet therapy increases the occurrence and severity of percutaneous transthoracic needle biopsy (PTNB)-related hemoptysis. MATERIALS AND METHODS: Our institutional review board approved this retrospective study, with waiver of informed consent. From May 2007 to December 2009, 1251 patients undergoing 1346 PTNBs constituted our study population. Of these PTNBs, 163 were performed in patients who had suspended antiplatelet therapy for less than 10 days (mean discontinuation time, 2.56 ± 2.35 days), and these patients were classified as antiplatelet agent users: 143 patients with single aspirin (mean discontinuation time, 2.55 ± 2.35 days), 12 patients with single clopidogrel (mean discontinuation time, 2.33 ± 2.10 days), and eight patients with dual-antiplatelet therapy (i.e., aspirin plus clopidogrel; mean discontinuation time, 3.12 ± 2.90 days). The influence of antiplatelet therapy on the occurrence and severity of PTNB-related hemoptysis was retrospectively evaluated. RESULTS: Among 1346 PTNBs, there were 128 cases (9.5%) of hemoptysis, including 21 cases of severe hemoptysis (1.6%). Multivariate analysis revealed that dual-antiplatelet therapy (odds ratio [OR], 10.09), female sex (OR, 1.88), smaller lesions (OR, 0.88), deeply located lesions (OR, 1.17), and the use of cutting needles (OR, 3.22) were independent risk factors for overall hemoptysis. For severe hemoptysis, dual-antiplatelet therapy (OR, 13.02), ground-glass nodules (OR, 8.86), and deeply located lesions (OR, 1.24) were proven to be independent risk factors. Single-antiplatelet therapy suspended for less than 10 days was not a significant risk factor for either overall or severe hemoptysis. CONCLUSION: Single-antiplatelet therapy suspended for less than 10 days is not an independent risk factor for the occurrence of PTNB-related hemoptysis, whereas dual-antiplatelet therapy increases its risk.

C-arm cone-beam CT-guided percutaneous transthoracic needle biopsy of small (≤ 20 mm) lung nodules: diagnostic accuracy and complications in 161 patients.

OBJECTIVE: The purpose of this study is to retrospectively evaluate the diagnostic accuracy and complications of C-arm cone-beam CT (CBCT)-guided percutaneous transthoracic needle biopsy (PTNB) for small (≤ 20 mm) lung nodules and their possible influencing factors. MATERIALS AND METHODS: From March 2009 to July 2010, 161 consecutive patients (77 men and 84 women; mean [± SD] age, 61 ± 11.8 years; range, 29-85 years) with 173 small (≤ 20 mm) lung nodules underwent CBCT-guided PTNB performed by an experienced chest radiologist in a tertiary referral hospital. The diagnostic accuracy, sensitivity, specificity, and complication rates were statistically evaluated, and influencing factors were assessed using univariate and subsequent multivariate analysis. RESULTS: Of 173 nodules (mean size, 15 ± 3.7 mm), 94 (54.3%) were diagnosed as malignant, 69 (39.9%) as benign, and 10 (5.8%) as indeterminate. On PTNB, 160 nodules were correctly diagnosed and three were false-negatives. Diagnostic accuracy, sensitivity, and specificity were 98.2%, 96.8%, and 100%, respectively. No factors significantly decreased diagnostic accuracy. As for complications, pneumothorax, hemoptysis, and chest pain occurred in 55 (31.8%), 25 (14.5%), and two (1.2%) patients, respectively. Multivariate analysis revealed that the presence of emphysema along the needle pathway was a significant risk factor (odds ratio [OR], 10.11), and the occurrence of hemoptysis was a significant protective factor (OR, 0.28) against pneumothorax. Ground-glass nodules were found to be a significant independent risk factor for hemoptysis (OR, 5.10). CONCLUSION: C-arm CBCT-guided PTNB is highly accurate for small lung nodules, and the diagnostic accuracy does not significantly decrease even in technically challenging conditions.

Computer-aided nodule detection and volumetry to reduce variability between radiologists in the interpretation of lung nodules at low-dose screening computed tomography.

OBJECTIVE: The aim of this study was to evaluate whether a computer-aided diagnosis (CAD) system improves interobserver agreement in the interpretation of lung nodules at low-dose computed tomography (CT) screening for lung cancer. MATERIALS AND METHODS: Baseline low-dose screening CT examinations from 134 participants enrolled in the National Lung Screening Trial were reviewed by 7 chest radiologists. All participants consented to the use of their deidentified images for research purposes. Screening results were classified as positive when noncalcified nodules larger than 4 mm in diameter were present. Follow-up evaluation was recommended according to the nodule diameter: 4 mm or smaller, more than 4 to 8 mm, and larger than 8 mm. When multiple nodules were present, recommendations were based on the largest nodule. Readers initially assessed the nodule presence visually and measured the average nodule diameter manually. Revision of their decisions after reviewing the CAD marks and size measurement was allowed. Interobserver agreement evaluated using multirater κ statistics was compared between initial assessment and that with CAD. RESULTS: Multirater κ values for the positivity of the screening results and follow-up recommendations were improved from moderate (κ = 0.53-0.54) at initial assessment to good (κ = 0.66-0.67) after reviewing CAD results. The average percentage of agreement between reader pairs on the positivity of screening results and follow-up recommendations per case was also increased from 77% and 72% at initial assessment to 84% and 80% with CAD, respectively. CONCLUSION: Computer-aided diagnosis may improve the reader agreement on the positivity of screening results and follow-up recommendations in the assessment of low-dose screening CT.

Reduction aortoplasty for the ascending aortic aneurysm with aortic valve disease. Does bicuspid valve matter?

BACKGROUND: The outcomes of reduction ascending aortoplasty (RAA) performed with aortic valve surgery were evaluated and the results of RAA in patients with bicuspid aortic valve (BAV) were compared with those in patients with tricuspid valve. METHODS AND RESULTS: From October 1994 to April 2009, 88 patients underwent RAA. Aortic valve was bicuspid in 45 patients (BAV group) and tricuspid in 43 patients (TAV group). Total circulatory arrest was required in 45 patients. Preoperative ascending aortic diameter was 45.5±4.7mm. Early mortality rate was 1.1%. Ten-year survival rate and freedom from cardiac death were 91.1% and 96.2%, respectively. No differences in clinical outcomes were found between the 2 groups. No aorta-related complications including aortic rupture, dissection and reoperation were observed. Aortic diameter at the last follow-up (61±43 months) was 37.8±4.3mm. The interval between surgery and follow-up CTA was associated with aneurysmal recurrence (P=0.022). Average rate of dilatation was 0.42±0.49mm/year (n=37). A need for total circulatory arrest was associated with an increase of the aortic diameter (P=0.009). BAV was associated with neither aneurysmal recurrence nor increase of aortic diameter. CONCLUSIONS: RAA in patients with an ascending aortic aneurysm combined with aortic valve disease could be performed with acceptable early and long-term outcomes, even in patients with BAV. Long-term follow-up evaluation might be necessary due to the risk of redilatation especially in patients with an extended aneurysm, which required total circulatory arrest for RAA.

Digital childhood: electronic media and technology use among infants, toddlers, and preschoolers.

OBJECTIVES: The objectives of this study were to describe media access and use among US children aged 0 to 6, to assess how many young children fall within the American Academy of Pediatrics media-use guidelines, to identify demographic and family factors predicting American Academy of Pediatrics media-use guideline adherence, and to assess the relation of guideline adherence to reading and playing outdoors. METHODS: Data from a representative sample of parents of children aged 0 to 6 (N = 1051) in 2005 were used. Descriptive analyses, logistic regression, and multivariate analyses of covariance were used as appropriate. RESULTS: On a typical day, 75% of children watched television and 32% watched videos/DVDs, for approximately 1 hour and 20 minutes, on average. New media are also making inroads with young children: 27% of 5- to 6-year-olds used a computer (for 50 minutes on average) on a typical day. Many young children (one fifth of 0- to 2-year-olds and more than one third of 3- to 6-year-olds) also have a television in their bedroom. The most common reason given was that it frees up other televisions in the house so that other family members can watch their own shows (54%). The majority of children aged 3 to 6 fell within the American Academy of Pediatrics guidelines, but 70% of 0- to 2-year-olds did not. CONCLUSIONS: This study is the first to provide comprehensive information regarding the extent of media use among young children in the United States. These children are growing up in a media-saturated environment with almost universal access to television, and a striking number have a television in their bedroom. Media and technology are here to stay and are virtually guaranteed to play an ever-increasing role in daily life, even among the very young. Additional research on their developmental impact is crucial to public health.

Linking obesity and activity level with children's television and video game use.

This study examined the links between childhood obesity, activity participation and television and video game use in a nationally representative sample of children (N = 2831) ages 1-12 using age-normed body mass index (BMI) ratings. Results indicated that while television use was not related to children's weight status, video game use was. Children with higher weight status played moderate amounts of electronic games, while children with lower weight status played either very little or a lot of electronic games. Interaction analyses revealed that this curvilinear relationship applied to children under age 8 and that girls, but not boys, with higher weight status played more video games. Children ages 9-12 with lower weight status used the computer (non-game) for moderate amounts of time, while those with higher weight status used the computer either very little or a lot. This was also true for the relationship between print use and weight status for children of all ages. Results also indicated that children with higher weight status spent more time in sedentary activities than those with lower weight status.