Coil spring-powered pump with inertial microfluidic chip for size-based isolation and enrichment of biological cells.

Microfluidic chips have been widely used for in vitro diagnostics using pretreatment of biological samples; however, biologists and clinical researchers have difficulties using them in resource-limited settings. Sample injection systems for microfluidic chips are bulky, expensive, electricity-powered, and complex. A coiled spring-powered device, which can be used to isolate variously sized cells with high efficiency continuously and passively, was developed for portable, low-cost, electricity-free, and simple sample injection. The flow driving power was provided by releasing the compression spring in the mechanical syringe driver with a one-click action. In general, a syringe pump generates a stable passive flow rate. However, the syringe pumps are large in size and expensive because they have many functions such as infusion/withdrawal flow injection and the use of syringes of various sizes, allowing them to be applied in a variety of applications performed in the laboratory. In addition, it is not suitable for portable devices because of the considerable amount of electric power required. To overcome these drawbacks, we developed a device prototype that sorts different-sized particles and separates rare tumor cells or blood cells from blood with high efficiency. The performance of the coiled spring-powered device was evaluated and found to be comparable with that of syringe pump-powered devices. In situations where trained personnel cannot handle microfluidic chips for isolating circulating biomarkers (CTCs, WBCs, or plasma) from blood samples, the coiled spring-powered device can provide diagnostic tools, especially in resource-limited countries.

Spatial ensemble modeling for predicting the potential distribution of Lymantria dispar asiatica (Lepidoptera: Erebidae: Lymantriinae) in South Korea.

The spongy moth, Lymantria dispar, is a pest that damages various tree species throughout North America and Eurasia, has recently emerged in South Korea, threatening local forests and landscapes. The establishment of effective countermeasures against this species' outbreak requires predicting its potential distribution with climate change. In this study, we used species distribution models (CLIMEX and MaxEnt) to predict the potential distribution of the spongy moth and identify areas at risk of exposure to a sustained occurrence of the pest by constructing an ensemble map that simultaneously projected the outcomes of the two models. The results showed that the spongy moth could be distributed over the entire country under the current climate, but the number of suitable areas would decrease under a climate change scenario. This study is expected to provide basic data that can predict areas requiring intensive control and monitoring in advance with methodologically improved modeling technique.

Influence of Root Color and Tissue on Phytochemical Contents and Antioxidant Activities in Carrot Genotypes.

This study monitored changes in major carotenoids (lutein, ⍺-carotene, and ß-carotene), free sugars (fructose, glucose, and sucrose), ascorbic acid, vitamin E, phytosterols (campesterol, stigmasterol, and ß-sitosterol), fatty acid composition, total phenol content (TPC), total flavonoid content (TFC), total anthocyanin content, and antioxidant activities (AA); ferric-reducing antioxidant power (FRAP) and 2,2'-azino-bis (3-ethylbenzothiazoline-6sulfonic acid) [ABTS] assays, in the inner and outer root tissues of nine carrot genotypes with orange, white, and purple roots. The results showed a differential accumulation of bioactive compounds and antioxidant activities depending on root tissue and color. Carotenoids, free sugars, and total phytosterol contents were higher in genotypes with orange roots than in other genotypes. Ascorbic acid, TPC, TFC, total anthocyanin, and AA were highest in purple-colored carrots while vitamin E content was higher in white/purple carrots. Root color was highly related to the accumulation of individual carotenoids, vitamin E isomers, and total anthocyanin content most prominently among the analyzed bioactive compounds and AA. Free sugar and carotenoid contents were relatively higher in outer tissues than in inner tissues. Furthermore, ascorbic acid, TPC, TFC, and AA were statistically higher or similar in outer tissues when compared to inner tissues in all genotypes. In contrast, trends in vitamin E and phytosterol content were inconsistent between the inner and outer tissues, depending on the genotype. Although fatty acid composition was affected by both root color and tissue, the results were not significant. Thus, the phytochemical profile and content were highly dependent on root color and tissue in carrot genotypes. This may be useful in the food processing and pharmaceutical industries for the extraction of targeted bioactive compounds.

Effect of leukopenia induced by cyclophosphamide on the initial stage of arterial thrombosis in mice.

INTRODUCTION: Leukocytes are found in organizing thrombi and are associated with thrombus growth. However, their role in the initial stage of thrombus formation is not well known. We investigated the role of leukocytes in the early stage of arterial thrombosis by inducing leukopenia. METHODS: In this double-blind, randomized, placebo-controlled study, 72 Institute of Cancer Research mice were randomly treated with intraperitoneal 100 mg/kg cyclophosphamide or normal saline. The primary outcome was time to occlusion after FeCl3 treatment. We also compared thrombus size, histological composition, and association with peripheral blood cell counts between cyclophosphamide and control groups. RESULTS: Cyclophosphamide treatment significantly decreased leukocyte counts by 82.8% compared to placebo (P < 0.001). The time to occlusion was significantly longer in the cyclophosphamide group (3.31 ± 1.59 min) than in the control group (2.30 ± 1.14 min; P = 0.003). The immunoreactivity for Ly6G-positive cells, intracellular histone H3, and released histone H3 in thrombi was significantly reduced in the cyclophosphamide group by 92.8%, 50.2%, and 34.3%, respectively. Time to occlusion had a moderate negative correlation with leukocyte count in peripheral blood (r = -0.326, P = 0.022) in the entire group. CONCLUSIONS: Cyclophosphamide-induced leukopenia attenuated thrombus formation during the early stage of arterial thrombosis. Our findings suggest the potential role of leukocytes in the initial stage of arterial thrombosis.

Automatically Controlled Microfluidic System for Continuous Separation of Rare Bacteria from Blood.

Bloodstream infection by microorganisms is a major public health concern worldwide. Millions of people per year suffer from microbial infections, and current blood culture-based diagnostic methods are time-consuming because of the low concentration of infectious microorganisms in the bloodstream. In this study, we introduce an efficient automated microfluidic system for the continuous isolation of rare infectious bacteria (Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa) from blood. Bacteria received a balanced force between a fluidic drag force and a periodically controlled dielectrophoretic (DEP) force from tilted electrodes to minimize cell adhesion to the electrodes, which prevented the loss of rare infectious bacteria. Target bacteria were efficiently segregated from the undesired blood cells to ensure that only the bacteria received the DEP force under the hypotonic condition, while the blood cells received no DEP force and exited the channel via a laminar flow. Thus, the bacteria were successfully extracted from the blood with a high recovery yield of 91.3%, and the limit of the bacteria concentration for isolation was 100 cfu/ml. We also developed an automated system that performed every step from blood-sample loading to application of electricity to the microfluidic chip for bacteria separation. It reduced the standard deviation of the bacteria recovery yield from 6.16 to 2.77 compared with the conventional batch process, providing stable bacteria-extraction performance and minimizing errors and bacteria loss caused by user mistakes. © 2019 International Society for Advancement of Cytometry.

Inter-observer agreement in identifying traction bronchiectasis on computed tomography: its improvement with the use of the additional criteria for chronic fibrosing interstitial pneumonia.

PURPOSE: To assess inter-observer variability in identifying traction bronchiectasis on computed tomography (CT) using additional criteria for chronic fibrosing interstitial pneumonia. METHODS: Seven experts categorized CT image set representing 39 patients into three groups on the basis of the presence of traction bronchiectasis, using a three-point scale: 3-definitely/probably yes; 2-possibly yes; and 1-definitely/probably no. This scale served as a reference standard. The image set included cases of chronic fibrosing interstitial pneumonia, non-interstitial lung disease, and difficult-to-determine cases. Forty-eight observers similarly assessed the same image set, first according to the Fleischner Society definition, and second with additional criteria, in which traction bronchiectasis was observed exclusively in chronic fibrosing interstitial pneumonia. The agreement level between the reference standard and each observer's evaluation in each session was calculated using weighted kappa values which were compared between the two sessions using a paired t test. RESULTS: The mean weighted kappa value for all observers was significantly higher in the second reading session (mean 0.75) than in the first reading session (mean 0.62) (p < 0.001). CONCLUSION: Inter-observer agreement in identifying traction bronchiectasis improves when using the additional criteria which specify chronic fibrosing interstitial pneumonia as the underlying disease.

Cancer cell-induced neutrophil extracellular traps promote both hypercoagulability and cancer progression.

INTRODUCTION: Neutrophils can generate extracellular net-like structures by releasing their DNA-histone complexes and antimicrobial peptides, which is called neutrophil extracellular traps (NETs). Various stimuli can induce NET formation. In particular, neutrophils and NET formation are abundant in tumor tissue. This study investigated how cancer cells induce NET formation and whether this NET formation promotes plasma thrombin generation and cancer progression. METHODS: Induction of NET formation by a pancreatic cancer cell line (AsPC-1) was assessed by measuring the histone-DNA complex level. The endogenous thrombin potential (ETP) was measured by thrombin generation assay. In vitro migration, invasion, and tubule formation assays were performed. The circulating levels of NET markers and hypercoagulability markers were assessed in 62 patients with pancreatobiliary malignancy and 30 healthy controls. RESULTS: AsPC-1 significantly induced NET formation in a dose-dependent manner. Conditioned medium (CM) from AsPC-1 also induced NETs. Interestingly, NET-formation was abolished by heat-inactivated CM, but not by lipid-extracted CM, suggesting an important role of protein components. A reactive oxygen species inhibitor did not inhibit cancer cell-induced NET formation, but prostaglandin E1 (PGE1, cyclic adenosine monophosphate inducer) and antithrombin did. NETs significantly increased ETP of normal plasma. Of note, NETs promoted cancer cell migration and invasion as well as angiogenesis, which were inhibited by histone-binding agents (heparin, polysialic acid), a DNA-degrading enzyme, and Toll-like receptor neutralizing antibodies. In patients with pancreatobiliary malignancy, elevated NET markers correlated well with hypercoagulability makers. CONCLUSION: Our findings indicate that cancer cell-induced NET formation enhances both hypercoagulability and cancer progression and suggest that inhibitors of NET formation such as PGE1 and antithrombin can be potential therapeutics to reduce both hypercoagulability and cancer progression.

HBsAg-Negative, Anti-HBc-Negative Patients Still Have a Risk of Hepatitis B Virus-Related Hepatitis after Autologous Stem Cell Transplantation for Multiple Myeloma or Malignant Lymphoma.

PURPOSE: Although hepatitis B surface antigen (HBsAg)-negative, hepatitis B core antibody (anti-HBc)-negative patients are not considered to be at risk for hepatitis B virus (HBV)-related hepatitis, the actual risk remains to be elucidated. This study aimed to evaluate the risk of HBV-related hepatitis in HBsAg-negative, anti-HBc-negative patients receiving autologous stem cell transplantation (ASCT) for multiple myeloma (MM) or malignant lymphoma. MATERIALS AND METHODS: We retrospectively reviewed data from 271 HBsAg-negative patients (161 anti-HBc-negative and 110 anti-HBc-positive at the time of ASCT) who received ASCT for MM or lymphoma. The risk of HBV-related hepatitis was analyzed according to the presence of anti-HBc. HBV serology results at the time of ASCT were compared with those at the time of diagnosis of MM or lymphoma. RESULTS: Three patients (two anti-HBc-negative MMs and one anti-HBc-positive MM) developed HBV-related hepatitis after ASCT. The rate of HBV-related hepatitis did not differ among patients with or without anti-HBc status (p=0.843). HBV-related hepatitis more frequently occurred in MM patients than in lymphoma patients (p=0.041). Overall, 9.1% of patients (16.7% with MM and 5.4% with lymphoma) who were HBsAg-negative and anti-HBc-positive at the time of diagnosis had lost anti-HBc positivity during chemotherapy prior to ASCT. CONCLUSION: Our data suggest that HBsAg-negative, anti-HBc-negative patients at the time of ASCT for MM or lymphoma still might be at a risk for HBV-related hepatitis.

Added value of prone CT in the assessment of honeycombing and classification of usual interstitial pneumonia pattern.

OBJECTIVE: To retrospectively investigate whether prone CT improves identification of honeycombing and classification of UIP patterns in terms of interobserver agreement and accuracy using pathological results as a reference standard. MATERIALS AND METHODS: Institutional review board approval with waiver of patients' informed consent requirement was obtained. HRCTs of 86 patients with pathologically proven UIP, NSIP and chronic HP between January 2011 and April 2015 were evaluated by 8 observers. Observers were asked to review supine only set and supine and prone combined set and determine the presence of honeycombing and UIP classification (UIP, possible UIP, inconsistent with UIP). The diagnosis was regarded as correct when UIP pattern on CT corresponded to pathological UIP. RESULTS: Interobserver agreement of honeycombing identification among radiologists was only fair on the supine and combined set (weighted κ=0.31 and 0.34). Additional review of prone images demonstrated a significant improvement in interobserver agreement (weighted κ) of UIP classification from 0.25 to 0.33. Prone CT conferred a significant improvement in interobserver agreement of UIP classification for trainee radiologists (from 0.10 to 0.34) while no improvement was found for board-certified radiologists (from 0.35 to 0.31). There were no significant differences in the accuracy of UIP pattern with reference to pathological results between the supine and combined set (78.8% (145/184) and 81.3% (179/220), P=0.612). CONCLUSION: Additional review of prone CT can improve overall interobserver agreement of UIP classification among radiologists with variable experiences, particularly for less experienced radiologists, while no improvement was found in honeycombing identification.

Pretreatment Lymphopenia, Poor Performance Status, and Early Courses of Therapy Are Risk Factors for Severe Bacterial Infection in Patients with Multiple Myeloma during Treatment with Bortezomib-based Regimens.

The aim of this study was to identify the risk factors associated with severe bacterial infection (SBI) in multiple myeloma (MM) patients during treatment with bortezomib-based regimens. A total of 98 patients with MM were evaluated during 427 treatment courses. SBI occurred in 57.1% (56/98) of the patients and during 19.0% (81/427) of the treatment courses. In the multivariate analysis for the factors associated with the development of SBI in each treatment course, poor performance status (Eastern Cooperative Oncology Group ≥ 2, P < 0.001), early course of therapy (≤ 2 courses, P < 0.001), and pretreatment lymphopenia (absolute lymphocyte count < 1.0 × 10(9)/L, P = 0.043) were confirmed as independent risk factors. The probability of developing SBI were 5.1%, 14.9%, 23.9% and 59.5% in courses with 0, 1, 2, and 3 risk factors, respectively (P < 0.001). In conclusion, we identified three pretreatment risk factors associated with SBI in each course of bortezomib treatment. Therefore, MM patients with these risk factors should be more closely monitored for the development of SBI during bortezomib-based treatment.

The prognostic significance of monoclonal immunoglobulin gene rearrangement in conjunction with histologic B-cell aggregates in the bone marrow of patients with diffuse large B-cell lymphoma.

Bone marrow involvement (BMI) is a well-known poor prognostic factor in patients with diffuse large B-cell lymphoma (DLBCL). This study robustly investigated the significance of monoclonal immunoglobulin gene rearrangement combined with histologic B-cell aggregates in bone marrow (BM) in the detection of a poor prognostic group. Pretreatment BM samples of 394 DLBCL patients were analyzed via the immunoglobulin gene rearrangement study and the microscopic examination. Monoclonal immunoglobulin gene rearrangement was detected in 25.4% of cases. Histologic B-cell aggregates with the features of large B-cell lymphoma aggregates, small cell B-cell lymphoma aggregates, or B-cell aggregates of unknown biological potential were observed in 12% of cases (6.9%, 1.3%, and 3.8%, respectively). Histologic B-cell aggregates were more associated with monoclonality than polyclonality. Cases with both monoclonality and histologic B-cell aggregates demonstrated close association with poor prognostic factors such as a higher International Prognostic Index score and showed an inferior overall survival rate when compared to cases with only monoclonality or only histologic B-cell aggregates. From the findings, a combination of monoclonality and histologic B-cell aggregates within the bone marrow was highly associated with poor prognosis and could be used to determine high-risk DLBLC patients with greater sensitivity and specificity than conventional microscopic examination or immunoglobulin gene rearrangement study alone.

Monoclonal and polyclonal gammopathy measured by serum free light chain and immunofixation subdivide the clinical outcomes of diffuse large B-cell lymphoma according to molecular classification.

Elevated serum free light chain (FLC) is known to be an adverse prognostic factor for diffuse large B-cell lymphoma (DLBCL). We hypothesized that monoclonal gammopathy (MG; elevated kappa [κ] or lambda [λ] FLC with an abnormal κ/λ ratio or a positive IF [immunofixation]) and polyclonal gammopathy (PG; elevated κ and/or λ FLC with a normal κ/λ ratio and a negative IF) would have different clinical outcome according to the molecular classification of DLBCL. In addition, MG would be a poor prognostic factor in patients with activated B-cell like type of DLBCL. Molecular classification of DLBCL, such as germinal center B-cell (GCB) type and non-GCB type, was performed according to the Hans algorithm. Among 175 newly diagnosed DLBCL patients, 96 (54.9 %) patients had an elevated FLC. MG and PG were observed in 34 and 68 patients, respectively. The 2-year overall survival (OS) and event-free survival (EFS) rates were 79.0 % and 71.6 %, respectively. In multivariate analysis, high-intermediate/high International Prognostic Index score and elevated FLC were significant for the OS (P = 0.002, P = 0.005, respectively) and EFS (P < 0.002, P = 0.010, respectively). MG and PG were also associated with inferior OS (P = 0.002, P = 0.011, respectively) and EFS (P = 0.002, P = 0.013, respectively). Ninety-six patients from a total 133 evaluable patients were classified to the non-GCB type. Patients with PG showed inferior clinical outcome for OS and EFS in patients with the GCB type (P = 0.006, P = 0.035, respectively). MG was a significant poor prognostic factor for OS and EFS in patients with the non-GCB type (P = 0.017, P = 0.004, respectively). MG was a poor prognostic maker in patients with the non-GCB type and PG was a poor prognostic indicator for the GCB type of DLBCL who were treated with R-CHOP.

Prediction of postoperative lung function in patients undergoing lung resection: dual-energy perfusion computed tomography versus perfusion scintigraphy.

OBJECTIVES: The purpose of this study was to assess the usefulness of dual-energy perfusion computed tomography (CT) for predicting postoperative lung function in patients undergoing lung resection. METHODS: Fifty-one patients (38 men, 13 women; mean age, 63.8 years) were prospectively enrolled and subsequently underwent dual-energy CT, perfusion scintigraphy, a pulmonary function test before surgery, and a pulmonary function test 6 months after surgery. Computed tomography was performed using dual-source CT with the dual-energy technique. Using weighted average images, each lobe was segmented and using perfusion images, the iodine value was quantitatively measured. Lobar perfusion was calculated by multiplying the volume of the lobe by the iodine value. The ratio of lobar perfusion per whole-lung perfusion was then calculated. The predicted postoperative forced expiratory volume during 1 second (post-FEV1) was calculated by multiplying the preoperative FEV1 by the fractional contribution of perfusion of the remaining lung. The agreement between the predicted post-FEV1 and the actual post-FEV1 was then evaluated. The percentage of error of the predicted post-FEV1 to that of the actual post-FEV1 was then calculated. RESULTS: Using the Bland-Altman method, the limits of agreement between the actual post-FEV1 and the predicted post-FEV1 were -29.3% and 26.9% for scintigraphy and -28.9% and 17.3% for CT. The percentage of error of CT (15.4%) was comparable with that of scintigraphy (17.8%). CONCLUSIONS: Dual-energy perfusion CT was more accurate than perfusion scintigraphy was for predicting postoperative lung function.

Primary endobronchial marginal zone B-cell lymphoma of bronchus-associated lymphoid tissue: CT findings in 7 patients.

OBJECTIVE: To investigate CT and (18)F-flurodeoxyglucose ((18)F-FDG) positron-emission tomography/CT findings of primary endobronchial marginal zone B-cell lymphoma of the bronchus-associated lymphoid tissue (BALT). MATERIALS AND METHODS: From June 2006 through April 2012, seven patients (six female, one male; age range, 21-61 years; mean age, 49 years) were examined who were pathologically diagnosed with the primary endobronchial marginal zone B-cell lymphoma of BALT. We evaluated the locations and characteristics of the lesions on CT and (18)F-FDG-PET/CT scans. The lesions were classified into the following three patterns: 1) solitary intraluminal nodule; 2) several tiny nodular protrusions; and 3) diffuse wall thickening. RESULTS: A solitary intraluminal nodule was observed in four patients (57.1%), several tiny nodular protrusion in two patients (28.6%), and diffuse wall thickening in one patient (14.3%). The lesions were categorized into 3 major locations: confined to the trachea (n = 3), confined to the lobar bronchus (n = 2), and diffuse involvement of the trachea and both main bronchi (n = 2). All lesions demonstrated homogeneous iso-attenuation as compared with muscle on pre- and post-enhancement scans. Secondary findings in the lungs (n = 3; 42.9%) included postobstructive lobar atelectasis (n = 1), air trapping (n = 1), and pneumonia (n = 1). On (18)F-FDG-PET/CT (n = 5), 4 lesions showed homogeneous uptake with maximum standardized uptake values (mSUV), ranging 2.3-5.7 (mean mSUV: 3.3). One lesion showed little FDG uptake. CONCLUSION: Primary endobronchial marginal zone B-cell lymphoma of the BALT manifests as three distinct patterns on CT, with the solitary intraluminal nodule presenting as the main pattern. Most lesions demonstrate homogeneous but weak FDG uptake on (18)F-FDG-PET/CT.

Quantitative assessment of change in regional disease patterns on serial HRCT of fibrotic interstitial pneumonia with texture-based automated quantification system.

OBJECTIVES: To evaluate the usefulness of a texture-based automated quantification system (AQS) for evaluating the extent and interval change of regional disease patterns on initial and follow-up high-resolution computed tomographies (HRCTs) of fibrotic interstitial pneumonia (FIP). METHODS: Eighty-nine patients with clinically and/or biopsy confirmed usual interstitial pneumonia (UIP) (n = 71) and non-specific interstitial pneumonia (NSIP) (n = 18) were included. An AQS to quantify five disease patterns (ground-glass opacity [GGO], reticular opacity [RO], honeycombing [HC], emphysema [EMPH], consolidation [CONS]) and normal lung was developed. The extent and interval changes of each disease pattern, FS (fibrosis score), TA (total abnormal lung fraction) of entire lung on initial and 1-year follow-up HRCTs were quantified. The agreement between the results of AQS and two readers was assessed. Results of AQS were correlated with forced vital capacity (FVC) and carbon monoxide diffusing capacity (DLco). RESULTS: The Intraclass correlation coefficient (ICC) study revealed acceptable agreement between visual assessment and AQS (r = 0.78, 0.66 for HC; 0.76, 0.61 for FS; 0.64, 0.68 for TA, initial and follow-up HRCTs, respectively). Linear regression analysis revealed the extent of HC, TA on initial CT, interval changes of FS contributed negatively to DLco, and interval changes of FS, TA contributed negatively to FVC. CONCLUSIONS: Our AQS is comparable with visual assessment for evaluating the disease extent and the interval changes of FIP on HRCT.

Interobserver variability in the CT assessment of honeycombing in the lungs.

PURPOSE: To quantify observer agreement and analyze causes of disagreement in identifying honeycombing at chest computed tomography (CT). MATERIALS AND METHODS: The institutional review board approved this multiinstitutional HIPAA-compliant retrospective study, and informed patient consent was not required. Five core study members scored 80 CT images with a five-point scale (5 = definitely yes to 1 = definitely no) to establish a reference standard for the identification of honeycombing. Forty-three observers from various subspecialties and geographic regions scored the CT images by using the same scoring system. Weighted κ values of honeycombing scores compared with the reference standard were analyzed to investigate intergroup differences. Images were divided into four groups to allow analysis of imaging features of cases in which there was disagreement: agreement on the presence of honeycombing, agreement on the absence of honeycombing, disagreement on the presence of honeycombing, and other (none of the preceding three groups applied). RESULTS: Agreement of scores of honeycombing presence by 43 observers with the reference standard was moderate (Cohen weighted κ values: 0.40-0.58). There were no significant differences in κ values among groups defined by either subspecialty or geographic region (Tukey-Kramer test, P = .38 to >.99). In 29% of cases, there was disagreement on identification of honeycombing. These cases included honeycombing mixed with traction bronchiectasis, large cysts, and superimposed pulmonary emphysema. CONCLUSION: Identification of honeycombing at CT is subjective, and disagreement is largely caused by conditions that mimic honeycombing.

Radiation dose reduction of chest CT with iterative reconstruction in image space - Part I: studies on image quality using dual source CT.

OBJECTIVE: To determine whether the image quality (IQ) is improved with iterative reconstruction in image space (IRIS), and whether IRIS can be used for radiation reduction in chest CT. MATERIALS AND METHODS: Standard dose chest CT (SDCT) in 50 patients and low dose chest CT (LDCT) in another 50 patients were performed, using a dual-source CT, with 120 kVp and same reference mAs (50 mAs for SDCT and 25 mAs for LDCT) employed to both tubes by modifying a dual-energy scan mode. Full-dose data were obtained by combining the data from both tubes and half-dose data were separated from a single tube. These were reconstructed by using a filtered back projection (FBP) and IRIS: full-dose FBP (F-FBP); full-dose IRIS (F-IRIS); half-dose FBP (H-FBP) and half-dose IRIS (H-IRIS). Objective noise was measured. The subjective IQ was evaluated by radiologists for the followings: noise, contrast and sharpness of mediastinum and lung. RESULTS: Objective noise was significantly lower in H-IRIS than in F-FBP (p < 0.01). In both SDCT and LDCT, the IQ scores were highest in F-IRIS, followed by F-FBP, H-IRIS and H-FBP, except those for sharpness of mediastinum, which tended to be higher in FBP. When comparing CT images between the same dose and different reconstruction (F-IRIS/F-FBP and H-IRIS/H-FBP) algorithms, scores tended to be higher in IRIS than in FBP, being more distinct in half-dose images. However, despite the use of IRIS, the scores were lower in H-IRIS than in F-FBP. CONCLUSION: IRIS generally helps improve the IQ, being more distinct at the reduced radiation. However, reduced radiation by half results in IQ decrease even when using IRIS in chest CT.

Radiation dose reduction of chest CT with iterative reconstruction in image space - Part II: assessment of radiologists' preferences using dual source CT.

OBJECTIVE: To evaluate the impact of radiation dose and reconstruction algorithms on radiologists' preferences, and whether an iterative reconstruction in image space (IRIS) can be used for dose reduction in chest CT. MATERIALS AND METHODS: Standard dose chest CT (SDCT) in 50 patients and low dose chest CT (LDCT) in another 50 patients were performed, using a dual-source CT, with 120 kVp and same reference mAs (50 mAs for SDCT and 25 mAs for LDCT) employed to both tubes by modifying the dual-energy scan mode. Full-dose data were obtained by combining the data from both tubes and half-dose data were separated from one tube. These were reconstructed by using a filtered back projection (FBP) and IRIS: full-dose FBP (F-FBP); full-dose IRIS (F-IRIS); half-dose FBP (H-FBP) and half-dose IRIS (H-IRIS). Ten H-IRIS/F-IRIS, 10 H-FBP/H-IRIS, 40 F-FBP/F-IRIS and 40 F-FBP/H-IRIS pairs of each SDCT and LDCT were randomized. The preference for clinical usage was determined by two radiologists with a 5-point-scale system for the followings: noise, contrast, and sharpness of mediastinum and lung. RESULTS: Radiologists preferred IRIS over FBP images in the same radiation dose for the evaluation of the lungs in both SDCT (p = 0.035) and LDCT (p < 0.001). When comparing between H-IRIS and F-IRIS, decreased radiation resulted in decreased preference. Observers preferred H-IRIS over F-FBP for the lungs in both SDCT and LDCT, even with reduced radiation dose by half in IRIS image (p < 0.05). CONCLUSION: Radiologists' preference may be influenced by both radiation dose and reconstruction algorithm. According to our preliminary results, dose reduction at 50% with IRIS may be feasible for lung parenchymal evaluation.

Prevalence of ligamentum arteriosum calcification on multi-section spiral CT and digital radiography.

To investigate the prevalence of ligamentum arteriosum calcification (LAC) on multi-section spiral CT and digital radiography. Five hundred and eight children and 232 adults who performed multi-section chest CT were included in this study and were divided into nine age groups: A (0-5 years), B (6-10 years), C (11-15 years), D (16-20 years), E (21-30 years), F (31-40 years), G (41-50 years), H (51-60 years), and I (61-70 years). Two radiologists assessed the presence of LAC on axial and coronal CT images, defined as focal calcific density on both or on one plane with attenuation >100 Hounsfield unit. The prevalence of LAC on CT was compared between children and adults, and between unenhanced and enhanced CT in children. The prevalence of LAC on digital radiography was evaluated in 476 children. The prevalence of definite LAC on unenhanced multi-section CT was significantly higher in children (37.8 %) than in adults (11.2 %) (P < 0.001), with prevalences in groups: A through I of 35.8, 48.7, 35.1, 28.6, 25.0, 10.2, 15.5, 7.8, and 5.6 %, respectively. The prevalences of indeterminate LAC in age groups A-I on unenhanced multi-section CT were 4.5, 12.8, 8.1, 19.0, 0.0, 0.0, 0.0, 2.0, and 1.9 %. In children, the prevalence of LAC was significantly higher on unenhanced than on enhanced CT (37.8 vs. 16.4 %, P < 0.001). The prevalence of LAC on digital radiography was 3.6 % in children. LAC is frequently observed in children and adults on multi-section spiral CT, more frequently than previously reported. Compared with that on multi-section spiral CT, the prevalence of LAC on digital radiography is substantially low.