Visualization of the Small Airways:What It Is and Why It Matters

When the earth transitioned to an oxygen-containing atmosphere, many bacterial species were killed by the free radicals that developed in their cytoplasm. New life forms took advantage of this change by evolving to use oxygen as the final resting place for electrons involved in the Krebs cycle. Animals today rely on getting oxygen into the blood stream and getting carbon dioxide out by ventilation through sequentially smaller and smaller tubes until diffusion takes over, finally reaching the terminal respiratory bronchiole and its associated alveoli for gas exchange. All animals are obligate aerobes. One group has estimated that there are 274 to 790 million alveoli in the healthy adult lung. In this issue of Radiology, Kim et al describe a visualization method to study the invisible small airways (seven to 30th generation) that move air from the trachea to the peripheral airways and back again for normal ventilation

Chest MRI in children: Why bother?

In this issue of Respirology, Montella and colleagues ask this question: How does high‐field chest MRI compare with CT of children with non‐cystic fibrosis (CF) lung disease? In an important extension of the first description of this study where they compared MRI and CT with pulmonary function measurements, the authors evaluated how widely‐used chest CT and almost never‐utilized lung MRI compare for diagnostic imaging of chronic lung disease. Here they show that high‐field (3Tesla as compared with the 1.5Tesla clinical standard) thoracic MRI has high reliability and good‐to‐excellent agreement with CT, definitively answering the important question at hand; their results support more widespread and routine use of MRI in longitudinal monitoring of chronic lung disease, especially in children as well as further optimization and improvement of lung MRI methods. Importantly, non‐CF lung disease accounts for the majority of paediatric pulmonary abnormalities and the increasing prevalence and economic burden related to chronic respiratory disease should motivate the research and development of novel MRI methods for serial and longitudinal imaging

Three-dimensional ultrasound scanning

The past two decades have witnessed developments of new imaging techniques that provide three-dimensional images about the interior of the human body in a manner never before available. Ultrasound (US) imaging is an important cost-effective technique used routinely in the management of a number of diseases. However, two-dimensional viewing of three-dimensional anatomy, using conventional two-dimensional US, limits our ability to quantify and visualize the anatomy and guide therapy, because multiple two-dimensional images must be integrated mentally. This practice is inefficient, and may lead to variability and incorrect diagnoses. Investigators and companies have addressed these limitations by developing three-dimensional US techniques. Thus, in this paper, we review the various techniques that are in current use in three-dimensional US imaging systems, with a particular emphasis placed on the geometric accuracy of the generation of three-dimensional images. The principles involved in three-dimensional US imaging are then illustrated with a diagnostic and an interventional application: (i) three-dimensional carotid US imaging for quantification and monitoring of carotid atherosclerosis and (ii) three-dimensional US-guided prostate biopsy

This is what COPD looks like

Despite decades of research, and the growing healthcare and societal burden of chronic obstructive pulmonary disease (COPD), therapeutic COPD breakthroughs have not occurred. Sub-optimal COPD patient phenotyping, an incomplete understanding of COPD pathogenesis and a scarcity of sensitive tools that provide patient-relevant intermediate endpoints likely all play a role in the lack of new, efficacious COPD interventions. In other words, COPD patients are still diagnosed based on the presence of persistent airflow limitation measured using spirometry. Spirometry measurements reflect the global sum of all the different possible COPD pathologies and perhaps because of this, we lose sight of the different contributions of airway and parenchymal abnormalities. With recent advances in thoracic X-ray computed tomography (CT) and magnetic resonance imaging (MRI), lung structure and function abnormalities may be regionally identified and measured. These imaging endpoints may serve as biomarkers of COPD that can be used to better phenotype patients. Therefore, here we review novel CT and MRI measurements that help reveal COPD phenotypes and what COPD really \u27looks\u27 like, beyond spirometric indices. We discuss MR and CT imaging approaches for generating reproducible and sensitive measurements of COPD phenotypes related to pulmonary ventilation and perfusion as well as airway and parenchyma anatomical and morphological features. These measurements may provide a way to advance the development and testing of new COPD interventions and therapies

Evidence of adult lung growth in humans.

A 33-year-old woman underwent a right-sided pneumonectomy in 1995 for treatment of a lung adenocarcinoma. As expected, there was an abrupt decrease in her vital capacity, but unexpectedly, it increased during the subsequent 15 years. Serial computed tomographic (CT) scans showed progressive enlargement of the remaining left lung and an increase in tissue density. Magnetic resonance imaging (MRI) with the use of hyperpolarized helium-3 gas showed overall acinar-airway dimensions that were consistent with an increase in the alveolar number rather than the enlargement of existing alveoli, but the alveoli in the growing lung were shallower than in normal lungs. This study provides evidence that new lung growth can occur in an adult human

Imaging how and where we breathe oxygen: Another Big Short?

The Big Short tells the story of a small group of skeptics who profited from the financial crisis in 2007 by betting against collateralized (mortgage) debt obligations (CDO). Importantly, the novel paints a clear picture of the eccentric nature of contrarians who think divergently and against the grain or bet against an accepted truth or “sure” thing. In a similar manner, Ishii and co-workers’ recent work describes their team’s development of a pulmonary imaging technology that provides divergent and disruptive in vivo lung measurements of oxygen partial pressure in the context of the prevailing and longstanding consensus around FEV1 as the definitive diagnostic of chronic lung disease. The Big Short tells the story of a small group of skeptics who profited from the financial crisis in 2007 by betting against collateralized (mortgage) debt obligations (CDO). Importantly, the novel paints a clear picture of the eccentric nature of contrarians who think divergently and against the grain or bet against an accepted truth or “sure” thing. In a similar manner, Ishii and co-workers’ recent work describes their team’s development of a pulmonary imaging technology that provides divergent and disruptive in vivo lung measurements of oxygen partial pressure in the context of the prevailing and longstanding consensus around FEV1 as the definitive diagnostic of chronic lung disease

Accelerated 129Xe MRI morphometry of terminal airspace enlargement: Feasibility in volunteers and those with alpha-1 antitrypsin deficiency

PURPOSE: Multi-b diffusion-weighted hyperpolarized inhaled-gas MRI provides imaging biomarkers of terminal airspace enlargement including ADC and mean linear intercept (L METHODS: We evaluated multi-b (0, 12, 20, 30, and 45.5 s/cm RESULTS: For the HV subgroup, mean differences of 5%, 2%, and 8% were observed between fully sampled and undersampled k-space for ADC, L CONCLUSIONS: Accelerated multi-b diffusion-weighte

Carotid Artery Atherosclerosis in Patients with Active Rheumatoid Arthritis: Predictors of Plaque Occurrence and Progression Over 24 Weeks

INTRODUCTION: This study evaluated the prevalence and progression of subclinical carotid artery atherosclerosis in active rheumatoid arthritis (RA). METHODS: Carotid arteries of RA patients were scanned using 3D ultrasound at baseline and 24 weeks for total plaque area, vessel wall volume, and intima-media thickness (IMT), as well as arterial stiffness measured using pulse wave velocity. Variables related to inflammation, lipids and cardiovascular (CV) risk were assessed for associations with plaque progression. Of 195 screened patients, 31 met inclusion criteria (66 Swollen joint count (SJC) plus 68 Tender joint count (TJC)≥8 OR SJC plus TJC≥4 with elevated acute phase reactants) and were enrolled (27 female; mean age 59.3±9.8years). Patients using lipid lowering drugs and uncontrolled comorbidities were excluded. RESULTS: Atherosclerotic plaque occurred in 35% and arterial wall hypertrophy (IMT≥0.6mm) in 86% of patients. Most (68%) had an abnormal lipid profile characterized by reduced HDL and/or increased total cholesterol/HDL index, which was adversely affected by disease activity. Stepwise binary logistic regression analysis showed that Framingham risk score (OR=1.155, 95%CI:1.002-1.332, p=0.046) and ESR (OR=1.148, 95%CI:1.015-1.299, p=0.028) predicted plaque burden most strongly. Plaque progression was significantly associated with baseline higher hsCRP, ESR, and heavy smoking, but only hsCRP predicted plaque growth in multivariate regression analysis (p=0.004); and hsCRP was related to higher disease activity (r=0.443, p=0.016), LDL (r=0.544, p=0.007), and smoking (r=0.384, p=0.04). CONCLUSION: RA-related inflammation contributed to augmented CV burden in RA and might mediate its effect on atherosclerosis through hsCRP and modulation of the traditional CV risk factors, such as dyslipidemia