Participant selection for lung cancer screening by risk modelling (the Pan-Canadian Early Detection of Lung Cancer [PanCan] study): a single-arm, prospective study.

BACKGROUND: Results from retrospective studies indicate that selecting individuals for low-dose CT lung cancer screening on the basis of a highly predictive risk model is superior to using criteria similar to those used in the National Lung Screening Trial (NLST; age, pack-year, and smoking quit-time). We designed the Pan-Canadian Early Detection of Lung Cancer (PanCan) study to assess the efficacy of a risk prediction model to select candidates for lung cancer screening, with the aim of determining whether this approach could better detect patients with early, potentially curable, lung cancer. METHODS: We did this single-arm, prospective study in eight centres across Canada. We recruited participants aged 50-75 years, who had smoked at some point in their life (ever-smokers), and who did not have a self-reported history of lung cancer. Participants had at least a 2% 6-year risk of lung cancer as estimated by the PanCan model, a precursor to the validated PLCOm2012 model. Risk variables in the model were age, smoking duration, pack-years, family history of lung cancer, education level, body-mass index, chest x-ray in the past 3 years, and history of chronic obstructive pulmonary disease. Individuals were screened with low-dose CT at baseline (T0), and at 1 (T1) and 4 (T4) years post-baseline. The primary outcome of the study was incidence of lung cancer. This study is registered with ClinicalTrials.gov, number NCT00751660. FINDINGS: 7059 queries came into the study coordinating centre and were screened for PanCan risk. 15 were duplicates, so 7044 participants were considered for enrolment. Between Sept 24, 2008, and Dec 17, 2010, we recruited and enrolled 2537 eligible ever-smokers. After a median follow-up of 5·5 years (IQR 3·2-6·1), 172 lung cancers were diagnosed in 164 individuals (cumulative incidence 0·065 [95% CI 0·055-0·075], incidence rate 138·1 per 10 000 person-years [117·8-160·9]). There were ten interval lung cancers (6% of lung cancers and 6% of individuals with cancer): one diagnosed between T0 and T1, and nine between T1 and T4. Cumulative incidence was significantly higher than that observed in NLST (4·0%; p<0·0001). Compared with 593 (57%) of 1040 lung cancers observed in NLST, 133 (77%) of 172 lung cancers in the PanCan Study were early stage (I or II; p<0·0001). INTERPRETATION: The PanCan model was effective in identifying individuals who were subsequently diagnosed with early, potentially curable, lung cancer. The incidence of cancers detected and the proportion of early stage cancers in the screened population was higher than observed in previous studies. This approach should be considered for adoption in lung cancer screening programmes. FUNDING: Terry Fox Research Institute and Canadian Partnership Against Cancer.

A Multi-Step Algorithm for Measuring Airway Luminal Diameter and Wall Thickness in Lung CT Images.

Accurate measurements of airway diameter and wall thickness are important parameters in understanding numerous pulmonary diseases. Here, we describe an automated method of measuring small airway luminal diameter and wall thickness over numerous contiguous computed tomography (CT) images. Using CT lung images from 22 patients and an airway phantom, a seeded region-growing algorithm was first applied to identify the lumen of the airway. The result was applied as an initial region for boundary determination using the level set method. Once found, subsequent algorithmic expansion of the luminal border was used to calculate airway wall thickness. This algorithm automatically evaluates neighboring slices of the airway and measures the airway luminal diameter and wall thickness. This approach also detects airway bifurcations. Our new procedure provides rapid, automated, accurate, and clinically important lung airway measurements that would be useful to radiologists who use CT images for pulmonary disease assessment.

A morphological algorithm for measuring angle of airway branches in lung CT images.

Accurate measurement of human airway lumen bifurcation angle in the bronchial tree may be an important parameter for evidence of pulmonary diseases. Here, we describe a new method for recognizing and following airway bifurcation over numerous contiguous CT images. Based on morphological properties of airways and specific changes to airway properties while digitally navigating through the bifurcation, our method is able to track airways through several levels of bifurcation. Then, based on the center of the lumen area, determined by the level set segmentation algorithm, we estimate the centerline of each branch and calculate the angle between two bifurcating branches. By applying this method to an airway imaging phantom, we obtained accurate results in a short computational time. This new approach provides a rapid, automated, and accurate lung airway angle measurement and may prove useful to radiologists who use CT images for pulmonary disease assessment.

Implementation of a One-Day Living Kidney Donor Assessment Clinic to Improve the Efficiency of the Living Kidney Donor Evaluation: Program Report.

Purpose of program: A key barrier to becoming a living kidney donor is an inefficient evaluation process, requiring more than 30 tests (eg, laboratory and diagnostic tests), questionnaires, and specialist consultations. Donor candidates make several trips to hospitals and clinics, and often spend months waiting for appointments and test results. The median evaluation time for a donor candidate in Ontario, Canada, is nearly 1 year. Longer wait times are associated with poorer outcomes for the kidney transplant recipient and higher health care costs. A shorter, more efficient donor evaluation process may help more patients with kidney failure receive a transplant, including a pre-emptive kidney transplant (ie, avoiding the need for dialysis). In this report, we describe the development of a quality improvement intervention to improve the efficiency, effectiveness, and patient-centeredness of the donor candidate evaluation process. We developed a One-Day Living Kidney Donor Assessment Clinic, a condensed clinic where interested donor candidates complete all testing and consultations within 1 day. Sources of information: The One-Day Living Kidney Donor Assessment Clinic was developed after performing a comprehensive review of the literature, receiving feedback from patients who have successfully donated, and meetings with transplant program leadership from St. Joseph's Healthcare Hamilton. A multistakeholder team was formed that included health care staff from nephrology, transplant surgery, radiology, cardiology, social work, nuclear medicine, and patients with the prior lived experience of kidney donation. In the planning stages, the team met regularly to determine the objectives of the clinic, criteria for participation, clinic schedule, patient flow, and clinic metrics. Methods: Donor candidates entered the One-Day Clinic if they completed initial laboratory testing and agreed to an expedited process. If additional testing was required, it was completed on a different day. Donor candidates were reviewed by the nephrologist, transplant surgeon, and donor coordinator approximately 2 weeks after the clinic for final approval. The team continues to meet regularly to review donor feedback, discuss challenges, and brainstorm solutions. Key findings: The One-Day Clinic was implemented in March 2019, and has now been running for 4 years, making iterative improvements through continuous patient and provider feedback. To date, we have evaluated more than 150 donor candidates in this clinic. Feedback from donors has been uniformly positive (98% of donors stated they were very satisfied with the clinic), with most noting that the clinic was efficient and minimally impacted work and family obligations. Hospital leadership, including the health care professionals from each participating department, continue to show support and collaborate to create a seamless experience for donor candidates attending the One-Day Clinic. Limitations: Clinic spots are limited, meaning some interested donor candidates may not be able to enter a One-Day Clinic the same month they come forward. Implications: This patient-centered quality improvement intervention is designed to improve the efficiency and experience of the living kidney donor evaluation, result in better outcomes for kidney transplant recipients, and potentially increase living donation. Our next step is to conduct a formal evaluation of the clinic, measuring qualitative feedback from health care professionals working in the clinic and donor candidates attending the clinic, and measuring key process and outcome measures in donor candidates who completed the one-day assessment compared with those who underwent the usual care assessment. This program evaluation will provide reliable, regionally relevant evidence that will inform transplant centers across the country as they consider incorporating a similar one-day assessment model.

Objectifs du programme: Devenir donneur de rein vivant est difficile, le principal obstacle étant le processus d'évaluation inefficace auquel les candidats doivent se soumettre. Ce processus comporte plus de 30 examens (p. ex. tests de laboratoire et tests diagnostiques), questionnaires et consultations avec des spécialistes. Les candidats donneurs font plusieurs visites dans les hôpitaux et cliniques, et passent souvent plusieurs mois à attendre des rendez-vous et des résultats de tests. En Ontario (Canada), le délai médian pour l'évaluation d'un candidat au don est de près d'un an. Les temps d'attente plus longs sont associés à de moins bons résultats pour les receveurs d'une greffe rénale, ainsi qu'à des coûts de soins de santé plus élevés. Un processus d'évaluation plus court et plus efficace des donneurs potentiels permettrait à un plus grand nombre de patients atteints d'insuffisance rénale de recevoir une greffe, y compris une greffe préventive (c.-à-d. permettant d'éviter la dialyse). Cet article décrit une intervention d'amélioration de la qualité visant à augmenter l'efficience, l'efficacité et la personnalisation du processus d'évaluation des candidats au don. Nous avons développé une clinique d'un jour pour l'évaluation des donneurs de reins vivants (One-Day Living Kidney Donor Assessment Clinic), soit une clinique condensée où les candidats passent tous les tests et consultent un spécialiste dans la même journée. Sources de l'information: La clinique d'un jour pour l'évaluation des donneurs de reins vivants a été développée à la suite d'un examen approfondi de la littérature, de la consultation des commentaires de patients ayant donné avec succès et de rencontres avec les dirigeants du programme de transplantation du St Joseph's Healthcare d'Hamilton. Une équipe multipartite a été formée; celle-ci réunit du personnel soignant en néphrologie, chirurgie de transplantation, radiologie, cardiologie, travail social et médecine nucléaire, ainsi que des patients ayant une expérience vécue du don de rein. L'équipe s'est réunie régulièrement pendant les étapes de planification pour déterminer les objectifs, les paramètres et le calendrier de la clinique, ainsi que les critères de participation et le flux de patients. Méthodologie: Les donneurs potentiels qui avaient complété les tests de laboratoire initiaux et qui acceptaient de se soumettre à un processus accéléré ont été évalués à la clinique d'un jour. Si des tests supplémentaires étaient nécessaires, ceux-ci étaient effectués un autre jour. Les candidats ont été rencontrés par le néphrologue, le chirurgien de transplantation et le coordonnateur des dons environ deux semaines après leur visite à la clinique pour l'approbation finale. L'équipe multipartite continue de se réunir régulièrement pour examiner les commentaires des donneurs, discuter des défis et trouver des solutions. Principaux résultats: La clinique d'un jour, mise sur pied en mars 2019, est en activité depuis quatre ans et permet des améliorations itératives grâce à la rétroaction continue des patients et des soignants. À ce jour, plus de 150 candidats au don ont été évalués à la clinique. Les commentaires des donneurs sont quasi unanimement positifs (98 % des candidats ont déclaré être très satisfaits de la clinique), la plupart soulignant l'efficacité de la clinique et les conséquences minimes du processus sur les obligations professionnelles et familiales. La direction de l'hôpital, tout comme les professionnels de la santé des services participants, continue d'appuyer la clinique d'un jour et de collaborer à la création d'une expérience fluide pour les donneurs potentiels qui la fréquentent. Limites: Les places à la clinique sont limitées; ainsi, certains candidats au don d'un rein vivant pourraient ne pas pouvoir être admis dans le mois où ils se présentent à la clinique. Conclusion: Cette intervention d'amélioration de la qualité axée sur les patients est conçue pour augmenter l'efficacité du processus d'évaluation et bonifier l'expérience des donneurs de rein vivants. Elle vise également à améliorer les résultats des receveurs d'une greffe rénale et, potentiellement, augmenter le don vivant. La prochaine étape sera une évaluation formelle de la clinique, c'est-à-dire la mesure de la rétroaction qualitative des professionnels de la santé qui y travaillent et des candidats au don qui la fréquentent, et l'analyse des processus clés et des résultats des candidats évalués à la clinique d'un jour par rapport à ceux qui suivent le processus d'évaluation habituel. Cette évaluation du programme fournira des données probantes fiables et propres à la région qui pourront informer les centres de transplantation de tout le pays qui envisagent d'intégrer un processus d'évaluation similaire.

Luminal mucus plugs are spatially associated with airway wall thickening in severe COPD and asthma: A single-centered, retrospective, observational study.

BACKGROUND: Airway wall thickening and excess airway mucus occur in asthma and chronic obstructive pulmonary disease (COPD), but few studies have investigated the relationship between them. Our objective was to determine the association between computed tomography (CT) airway wall thickening in segmental airways proximal to airways with or without mucus plugging in patients with asthma and COPD. METHODS: Mucus plugging was scored using a CT bronchopulmonary segment-based scoring system in asthma and COPD patients. For each of the 19 segmental airways, a mucus plug was defined as complete occlusion of one or more of the daughter branches (sub-segmental airways) by mucus. CT airway measurements were generated for each of the 19 segmental airways: wall-area-percentage (WA%), lumen area (LA), and total airway count (TAC) (VIDA Diagnostics Inc.). Multivariable logistic regression models were constructed for the presence of mucus plugs with corresponding CT measurement and adjusted by covariates; each of the 19 segments was treated as a nested variable. RESULTS: A total of 33 participants were evaluated. Participants had a mean age of 60 ± 15yrs and there were n = 14 (42%) males. There were 16 (48%) participants with a diagnosis of asthma and 17 (52%) with a COPD diagnosis. The mean FEV1 was 53 ± 21%pred and FEV1/FVC was 54 ± 15%. The mean mucus score in all participants was 15 ± 4 (min = 0, max = 19). Multivariable logistic regression analysis showed the presence of airway mucus was significantly associated with increased CT WA% (ß = 7.30, p = 0.004) and reduced TAC (ß = -0.06, p = 0.045). CONCLUSIONS: There was increased airway wall thickness and reduced airway counts on CT in segments where there was a distal mucus plug compared to segments without mucus plugs in asthma and COPD.

A multicentered, randomized, controlled trial comparing radioguided seed localization to standard wire localization for nonpalpable, invasive and in situ breast carcinomas.

BACKGROUND: Studies suggest radioguided seed localization (RSL) yields fewer positive margins than wire-guided localization (WL). The goal of this study is to determine whether RSL is superior to WL. METHODS: Women with confirmed invasive or ductal carcinoma in situ (DCIS) undergoing localization and breast conserving surgery were enrolled. Outcomes measured include positive margin and reoperation rates, specimen weight, operative and localization times, and surgeon and radiologist ranking of procedural difficulty. RESULTS: Randomization was centralized, concealed, and stratified by surgeon with 153 patients in the WL group and 152 in RSL group. Localizations were performed using either ultrasound (70%) or mammographic guidance (30%). Pathology was either DCIS (18%) or invasive carcinoma (82%). Procedures were performed at 3 sites, by 7 surgeons. Only difference found for patient and tumor characteristics was more multifocal disease in RSL group. Using intention-to-treat analysis, there were no differences in positive margins rates for RSL (10.5%) and WL (11.8%), (P=.99) or for positive or close margins (<1 mm) (RSL 19% and WL 22%; P=.61). Mean operative time (minutes) was shorter for RSL (RSL 19.4 vs WL 22.2; P<.001). Specimen volume, weight, reoperation and localization times were similar. Surgeons ranked the seed technique as easier (P=.008), while radiologists ranked them similarly. Patient's pain rankings during wire localization were higher (P=.038). CONCLUSIONS: In contrast to other trials positive margin and reoperation rates were similar for RSL and WL. However, for RSL operative times were shorter, and the technique was preferred by surgeons, making it an acceptable method for localization.

Magnetic resonance imaging sialolithography: direct visualization of calculi in the submandibular gland using susceptibility-weighted imaging (SWI) at 3 Tesla.

Magnetic resonance imaging (MRI) sialolithography is a useful technique for evaluating acute and chronic sialadenitis. However, its major weakness is that stones are not imaged directly. We have developed an MRI technique that allows specific identification and localization of calculi within the submandibular salivary gland or duct. This test is noninvasive and does not require ionizing radiation or a sialogogue. By using 3-dimensional susceptibility-weighted imaging, one can probe MRI signal phase changes. Corrected positive filtered phase and magnitude images, acquired using susceptibility-weighted imaging, allowed identification and anatomical localization of calcified calculi in the submandibular gland with efficacy comparable to computed tomography.

Investigation of a logistic model for T2* dynamic susceptibility contrast magnetic resonance imaging (dscMRI) perfusion studies.

There are a number of T1- and T2-based dynamic contrast-enhanced magnetic resonance imaging pharmacokinetic modeling approaches to study cancer microvasculature. Alternatively, model-free approaches offer an easy, quantitative assessment of microcirculation. In this work, we investigate a 6-parameter model-free approach applied to a T2*-weighted echo-planar imaging bolus response curve. We tested this new approach on a small cohort of patients with clinically diagnosed primary rectal carcinoma before adjuvant chemoradiotherapy and surgical excision. Comparison with healthy muscle tissue shows that logistic parameters P1/P2, P4, and P5 offer good discrimination between tumor and healthy tissue. Bolus response logistic parameters P4 and P5 have been implicated in previous T1-based works as being important in the assessment of cancer malignancy. Further comparison of T2* parameters with signal attenuation amplitude (maximum signal drop) and percentage baseline signal loss also corroborates the models' ability to quantify the microenvironment.

Utilization of Salvage and Systemic Therapies for Recurrent Prostate Cancer as a Result of 18F-DCFPyL PET/CT Restaging.

PURPOSE: Our purpose was to investigate the effect of the addition of prostate-specific membrane antigen (PSMA)-targeted positron emission tomography/computed tomography (PET/CT) in patients with recurrent prostate cancer post-primary radiation therapy. METHODS AND MATERIALS: A prospective, multi-institutional clinical trial evaluated 2-(3-{1-carboxy-5-[(6-[18F]fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (18F-DCFPyL) PET/CT restaging in 79 men with recurrent prostate cancer post-primary radiation therapy. We report actual patient management and compare this with proposed management both before and after PSMA-targeted PET/CT. RESULTS: Most patients (59%) had a major change in actual management compared with pre-PET/CT proposed management. The rate of major change was underestimated by immediately post-PET/CT surveys (32%). Eighteen patients with PSMA avidity in the prostate gland suspicious for malignancy had a prostate biopsy. Sensitivity, specificity, and positive predictive values of PSMA uptake in the prostate were 86%, 67%, and 92%, respectively. Thirty percent of patients had directed salvage therapy and 41% underwent systemic therapy. Eleven out of 79 patients (14%) had high-dose-rate brachytherapy alone for local recurrence, and 91% were free of recurrence at a median follow-up of 20 months. CONCLUSIONS: Most patients had a major change in actual management compared with pre-PSMA-targeted PET/CT planned management, and this was underestimated by post-PET/CT questionnaires.

Blood oxygen level-dependent magnetic resonance imaging of the human liver: preliminary results.

OBJECTIVE: To investigate blood oxygen level-dependent (BOLD) response of human liver to hyperoxic exposure under fasting and postprandial conditions. METHODS: Twelve healthy volunteers and 1 patient with chronic liver disease underwent liver BOLD magnetic resonance imaging at 3.0T. The BOLD images of a single slice were collected (1 image per second) during 3 breathing cycles of hyperoxia (3 minutes, 100% oxygen) with 5 minutes medical air (20.8% oxygen) in both preprandial and postprandial states. The BOLD signal time courses were correlated with a predefined stimulus paradigm. RESULTS: Eight healthy subjects showed increased BOLD signal within 44.6% +/- 21.1% liver area in the fasting state with gas cycling. Two showed slightly reduced BOLD signal within 23.4% +/- 14.9% liver area in the fasting state with gas cycling. In the postprandial state, the degree of change in BOLD signal with gas cycling was reduced for both the subjects having increased and those having decreased signal with gas cycling (13.4% +/- 12.6% positive, 10.9% +/- 10.1% negative; P < 0.05). Chronic liver disease also demonstrated increased BOLD signal with gas cycling, but the correlation decreased postprandially. CONCLUSIONS: The proposed physiological challenges induce certain BOLD signal response patterns in healthy and diseased livers, which may be useful for assessing liver function.

Circulating fibrocytes are an indicator of poor prognosis in idiopathic pulmonary fibrosis.

RATIONALE: The clinical management of idiopathic pulmonary fibrosis (IPF) remains a major challenge due to lack of effective drug therapy or accurate indicators for disease progression. Fibrocytes are circulating mesenchymal cell progenitors that are involved in tissue repair and fibrosis. OBJECTIVES: To test the hypothesis that assay of these cells may provide a biomarker for activity and progression of IPF. METHODS: Fibrocytes were defined as cells positive for CD45 and collagen-1 by flow cytometry and quantified in patients with stable IPF and during acute exacerbation of the disease. We investigated the clinical and prognostic value of fibrocyte counts by comparison with standard clinical parameters and survival. We used healthy age-matched volunteers and patients with acute respiratory distress syndrome as control subjects. MEASUREMENTS AND MAIN RESULTS: Fibrocytes were significantly elevated in patients with stable IPF (n = 51), with a further increase during acute disease exacerbation (n = 7; P < 0.001 vs. control subjects). Patients with acute respiratory distress syndrome (n = 10) were not different from healthy control subjects or stable patients with IPF. Fibrocyte numbers were not correlated with lung function or radiologic severity scores, but they were an independent predictor of early mortality. The mean survival of patients with fibrocytes higher than 5% of total blood leukocytes was 7.5 months compared with 27 months for patients with less than 5% (P < 0.0001). CONCLUSIONS: Fibrocytes are an indicator for disease activity of IPF and might be useful as a clinical marker for disease progression. This study suggests that quantification of circulating fibrocytes may allow prediction of early mortality in patients with IPF.

A Prospective Study of 18F-DCFPyL PSMA PET/CT Restaging in Recurrent Prostate Cancer following Primary External Beam Radiotherapy or Brachytherapy.

PURPOSE: Radio-recurrent prostate cancer is typically detected by a rising prostate-specific antigen and may reflect local or distant disease. Positron emission tomography (PET) radiotracers targeting prostate-specific membrane antigen, such as 18F-DCFPyL have shown promise in restaging men with recurrent disease postprostatectomy but are less well characterized in the setting of radio-recurrent disease. METHODS AND MATERIALS: A prospective, multi-institutional study was conducted to evaluate the effect of 18F-DCFPyL PET/computed tomography (CT) when added to diagnostic imaging (DI; CT abdomen and pelvis, bone scan, multiparametric magnetic resonance imaging pelvis) for men with radio-recurrent prostate cancer. All men were imaged with DI and subsequently underwent 18F-DCFPyL PET/CT with local and central reads. Tie break reads were performed as required. Management questionnaires were completed after DI and again after 18F-DCFPyL PET/CT. Discordance in patterns of disease detected with 18F-DCFPyL PET/CT versus DI and changes in management were characterized. RESULTS: Seventy-nine men completed the study. Most men had T1 disease (62%) and Gleason score <7 (95%). Median prostate-specific antigen at diagnosis was 7.4 ng/mL and at relapse was 4.8 ng/mL. DI detected isolated intraprostatic recurrence in 38 out of 79 men (48%), regional nodal recurrence in 9 out of 79 (11%), distant disease in 12 out of 79 (15%), and no disease in 26 out of 79 (33%). 18F-DCFPyL PET/CT detected isolated intraprostatic recurrence in 38 out of 79 men (48%), regional nodal recurrence in 21 out of 79 (27%), distant disease in 24 out of 79 (30%), and no disease in 10 out of 79 (13%). DI identified 8 out of 79 (10%) patients to have oligometastatic disease, compared with 21 out of 79 (27%) with 18F-DCFPyL PET/CT. 18F-DCFPyL PET/CT changed proposed management in 34 out of 79 (43%) patients. CONCLUSIONS: 18F-DCFPyL PET/CT identified extraprostatic disease in twice as many men with radio-recurrent prostate cancer compared with DI and detected a site of recurrence in 87% of men compared with 67% with DI. Furthermore, 18F-DCFPyL PET/CT identified potentially actionable disease (prostate only recurrence or oligometastatic disease) in 75% of men and changed proposed management in 43% of men.

Identification of breast calcification using magnetic resonance imaging.

MRI phase and magnitude images provide information about local magnetic field variation (DeltaB0), which can consequently be used to understand tissue properties. Often, phase information is discarded. However, corrected phase images are able to produce contrast as a result of magnetic susceptibility differences and local field inhomogeneities due to the presence of diamagnetic and paramagnetic substances. Three-dimensional (3D) susceptibility weighted imaging (SWI) can be used to probe changes in MRI phase evolution and, subsequently, result in an alternate form of contrast between tissues. For example, SWI has been useful in the assessment of negative phase induced DeltaB0 modulation due to the presence of paramagnetic substances such as iron. Very little, however, has been done to assess positive phase induced contrast changes resulting from the presence of diamagnetic substances such as precipitated calcium. As ductal carcinoma in situ, which is the precursor of invasive ductal cancer, is often associated with breast microcalcification, the authors proposed using SWI as a possible visualization technique. In this study, breast phantoms containing calcifications (0.4-1.5 mm) were imaged using mammography, computed tomography (CT), and SWI. Corrected phase and magnitude images acquired using SWI allowed identification and correlation of all calcifications seen on CT. As the approach is a 3D technique, it could potentially allow for more accurate localization and biopsy and maybe even reduce the use of gadolinium contrast. Furthermore, the approach may be beneficial to women with dense breast tissue where the ability to detect microcalcification with mammography is reduced.

Lung cancer associated with cystic airspaces: Characteristic morphological features on CT in a series of 11 cases.

PURPOSE: To familiarize the reader with the entity 'lung cancer associated with cystic airspaces' (LC-CAS) and create an awareness about the potential for slow progressive development of cancer within these nonaggressive appearing cystic airspaces (CAS) encountered in routine radiology practice. MATERIAL AND METHODS: Morphological appearances of (n = 11) LC-CAS detected during routine radiological reporting of chest CT scans were studied. Patient demographics, clinical history, characteristics of LC-CAS including location, size, wall thickening, diffuse nodularity, eccentric nodule, ground glass change, emphysema and pathology results were collected from the hospital's internal database. RESULTS: Patients with LC-CAS (9F/2M) were between 49 and 77 years (mean 63.18 years). All patients (n = 11) had a history of smoking. LC-CAS had a characteristic multicystic bubbly appearance. Average size of CAS at initial detection of LC was 2.52 cm (range 1.3-4 cm). Lesions were located in the RLL (n = 4), RML (n = 2), RUL (n = 1), LLL (n = 1) and LUL (n = 3) with no lobar predilection and were more commonly peripheral (n = 7) than central (n = 4). Ground glass change (n = 2), extrinsic nodules (n = 4), diffuse wall nodularity (n = 3) and intrinsic nodules (n = 2) were observed and prompted biopsy. Lesions ranged between T1a to T4. Most cancers were T1a N0 (n = 5). Adenocarcinomas formed the majority of cases (n = 9). CONCLUSION: LC-CAS present as new development of diffuse nodularity, eccentric nodules or ground glass change associated with CAS. These are more commonly adenocarcinomas on histology. Recognition of CAS and appropriate malignancy workup when suspicious features are observed is essential to enable early detection of lung cancer.

CT and Functional MRI to Evaluate Airway Mucus in Severe Asthma.

BACKGROUND: Intraluminal contributor(s) to airflow obstruction in severe asthma are patient-specific and must be evaluated to personalize treatment. The occurrence and functional consequence of airway mucus in the presence or absence of airway eosinophils remain undetermined. OBJECTIVE: The objective of this study was to understand the functional consequence of airway mucus in the presence or absence of eosinophils and to identify biomarkers of mucus-related airflow obstruction. METHODS: Mucus plugs were quantified on CT scans, and their contribution to ventilation heterogeneity (using MRI ventilation defect percent [VDP]) was evaluated in 27 patients with severe asthma. Patients were dichotomized based on sputum eosinophilia such that the relationship between mucus, eosinophilia, and ventilation heterogeneity could be investigated. Fractional exhaled nitric oxide (Feno) and related cytokines in sputum were measured. RESULTS: Mucus plugging was present in 100% of asthma patients with sputum eosinophils and 36% of those without sputum eosinophils (P = .0006) and was correlated with MRI VDP prebronchodilator (r = 0.68; P = .0001) and postbronchodilator (r = 0.72; P < .0001). In a multivariable regression, both mucus and eosinophils contributed to the prediction of postbronchodilator MRI VDP (R2 = 0.75; P < .0001). Patients with asthma in whom the mucus score was high had raised Feno (P = .03) and IL-4 (P = .02) values. Mucus plugging correlated with Feno (r = 0.63; P = .005). CONCLUSIONS: Both airway eosinophils and mucus can contribute to ventilation heterogeneity in patients with severe asthma. Patients in whom mucus is the dominant cause of airway obstruction have evidence of an upregulated IL-4/IL-13 pathway that could be identified according to increased Feno level.

Predicting Malignancy Risk of Screen-Detected Lung Nodules-Mean Diameter or Volume.

OBJECTIVE: In lung cancer screening practice low-dose computed tomography, diameter, and volumetric measurement have been used in the management of screen-detected lung nodules. The aim of this study was to compare the performance of nodule malignancy risk prediction tools using diameter or volume and between computer-aided detection (CAD) and radiologist measurements. METHODS: Multivariable logistic regression models were prepared by using data from two multicenter lung cancer screening trials. For model development and validation, baseline low-dose computed tomography scans from the Pan-Canadian Early Detection of Lung Cancer Study and a subset of National Lung Screening Trial (NLST) scans with lung nodules 3 mm or more in mean diameter were analyzed by using the CIRRUS Lung Screening Workstation (Radboud University Medical Center, Nijmegen, the Netherlands). In the NLST sample, nodules with cancer had been matched on the basis of size to nodules without cancer. RESULTS: Both CAD-based mean diameter and volume models showed excellent discrimination and calibration, with similar areas under the receiver operating characteristic curves of 0.947. The two CAD models had predictive performance similar to that of the radiologist-based model. In the NLST validation data, the CAD mean diameter and volume models also demonstrated excellent discrimination: areas under the curve of 0.810 and 0.821, respectively. These performance statistics are similar to those of the Pan-Canadian Early Detection of Lung Cancer Study malignancy probability model with use of these data and radiologist-measured maximum diameter. CONCLUSION: Either CAD-based nodule diameter or volume can be used to assist in predicting a nodule's malignancy risk.

Segmentation of images of abdominal organs.

Abdominal organ segmentation, which is, the delineation of organ areas in the abdomen, plays an important role in the process of radiological evaluation. Attempts to automate segmentation of abdominal organs will aid radiologists who are required to view thousands of images daily. This review outlines the current state-of-the-art semi-automated and automated methods used to segment abdominal organ regions from computed tomography (CT), magnetic resonance imaging (MEI), and ultrasound images. Segmentation methods generally fall into three categories: pixel based, region based and boundary tracing. While pixel-based methods classify each individual pixel, region-based methods identify regions with similar properties. Boundary tracing is accomplished by a model of the image boundary. This paper evaluates the effectiveness of the above algorithms with an emphasis on their advantages and disadvantages for abdominal organ segmentation. Several evaluation metrics that compare machine-based segmentation with that of an expert (radiologist) are identified and examined. Finally, features based on intensity as well as the texture of a small region around a pixel are explored. This review concludes with a discussion of possible future trends for abdominal organ segmentation.