Pulmonary MRI morphometry modeling of airspace enlargement in chronic obstructive pulmonary disease and alpha-1 antitrypsin deficiency.

PURPOSE: We generated lung morphometry measurements using single-breath diffusion-weighted MRI and three different acinar duct models in healthy participants and patients with emphysema stemming from chronic obstructive lung disease (COPD) and alpha-1 antitrypsin deficiency (AATD). METHODS: Single-breath-inhaled 3 He MRI with five diffusion sensitizations (b-value = 0, 1.6, 3.2, 4.8, and 6.4 s/cm2 ) was used, and signal intensities were fit using a cylindrical and single-compartment acinar-duct model to estimate MRI-derived mean linear intercept (Lm ) and surface-to-volume ratio (S/V). A stretched exponential model was also developed to estimate the mean airway length and Lm . RESULTS: We evaluated 42 participants, including 15 elderly never-smokers (69 ± 5 years), 12 ex-smokers without COPD (67 ± 11 years), 9 COPD ex-smokers (80 ± 6 years), and 6 AATD patients (59 ± 6 years). In the never- and ex-smokers, the diffusing capacity of the lung for carbon monoxide (DLCO ) and computed tomography relative area of less than -950 Hounsfield units (RA950 ) were normal, but these were abnormal in the COPD and AATD patients, which is reflective of emphysema. Although cylindrical and stretched-exponential-model estimates of Lm and S/V were not significantly different, the single-compartment-model estimates were significantly different (P < 0.05) for the never- and ex-smoker subgroups. All models estimated significantly worse Lm and S/V in the AATD and COPD subgroups compared with the never- and ex-smokers without emphysema. CONCLUSIONS: Differences in airspace enlargement may be estimated using Lm and S/V, generated using MRI and a stretched-exponential or cylindrical model of the acinar ducts. Magn Reson Med 79:439-448, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Pulmonary 3He Magnetic Resonance Imaging Biomarkers of Regional Airspace Enlargement in Alpha-1 Antitrypsin Deficiency.

RATIONALE AND OBJECTIVES: Thoracic x-ray computed tomography (CT) and hyperpolarized 3He magnetic resonance imaging (MRI) provide quantitative measurements of airspace enlargement in patients with emphysema. For patients with panlobular emphysema due to alpha-1 antitrypsin deficiency (AATD), sensitive biomarkers of disease progression and response to therapy have been difficult to develop and exploit, especially those biomarkers that correlate with outcomes like quality of life. Here, our objective was to generate and compare CT and diffusion-weighted inhaled-gas MRI measurements of emphysema including apparent diffusion coefficient (ADC) and MRI-derived mean linear intercept (Lm) in patients with AATD, chronic obstructive pulmonary disease (COPD) ex-smokers, and elderly never-smokers. MATERIALS AND METHODS: We enrolled patients with AATD (n = 8; 57 ± 7 years), ex-smokers with COPD (n = 8; 77 ± 6 years), and a control group of never-smokers (n = 5; 64 ± 2 years) who underwent thoracic CT, MRI, spirometry, plethysmography, the St. George's Respiratory Questionnaire, and the 6-minute walk test during a single 2-hour visit. MRI-derived ADC, Lm, surface-to-volume ratio, and ventilation defect percent were generated for the apical, basal, and whole lung as was CT lung area ≤-950 Hounsfield units (RA950), low attenuating clusters, and airway count. RESULTS: In patients with AATD, there was a significantly different MRI-derived ADC (P = .03), Lm (P < .0001), and surface-to-volume ratio (P < .0001), but not diffusing capacity of carbon monoxide, residual volume or total lung capacity, or CT RA950 (P > .05) compared to COPD ex-smokers with a significantly different St. George's Respiratory Questionnaire. CONCLUSIONS: In this proof-of-concept demonstration, we evaluated CT and MRI lung emphysema measurements and observed significantly worse MRI biomarkers of emphysema in patients with AATD compared to patients with COPD, although CT RA950 and diffusing capacity of carbon monoxide were not significantly different, underscoring the sensitivity of MRI measurements of AATD emphysema.

The patient with a heart murmur: evaluation, assessment and dental considerations.

BACKGROUND: Heart murmurs, a common finding in dental patients, are of major concern to dental professionals because certain dental procedures occasionally can induce severe cardiovascular complications. Murmurs may indicate existing heart disease that is a risk factor for infective endocarditis following a dental procedure, as well as more severe heart conditions such as congenital heart disease, atrial fibrillation or congestive heart failure. TYPES OF STUDIES REVIEWED: This review article is based on data published in peer-reviewed journals, including practice guidelines published by major dental and medical professional organizations. RESULTS: Echocardiography is the primary means of evaluating heart murmurs, and all dental professionals should become familiar with major aspects of an echocardiogram. Understanding the medical evaluation and assessment of a heart murmur fosters better communication with other health care professionals and results in improved patient care. CLINICAL IMPLICATIONS: Beyond the need to administer antibiotic prophylaxis, the dentist also needs to address the underlying causes of a patient's heart murmur. By providing dental care to such patients, oral health care providers become part of the patient's overall health care team.

Noninvasive quantification of alveolar morphometry in elderly never- and ex-smokers.

Diffusion-weighted magnetic resonance imaging (MRI) provides a way to generate in vivo lung images with contrast sensitive to the molecular displacement of inhaled gas at subcellular length scales. Here, we aimed to evaluate hyperpolarized (3)He MRI estimates of the alveolar dimensions in 38 healthy elderly never-smokers (73 ± 6 years, 15 males) and 21 elderly ex-smokers (70 ± 10 years, 14 males) with (n = 8, 77 ± 6 years) and without emphysema (n = 13, 65 ± 10 years). The ex-smoker and never-smoker subgroups were significantly different for FEV1/FVC (P = 0.0001) and DLCO (P = 0.009); while ex-smokers with emphysema reported significantly diminished FEV1/FVC (P = 0.02) and a trend toward lower DLCO (P = 0.05) than ex-smokers without emphysema. MRI apparent diffusion coefficients (ADC) and CT measurements of emphysema (relative area-CT density histogram, RA950) were significantly different (P = 0.001 and P = 0.007) for never-smoker and ex-smoker subgroups. In never-smokers, the MRI estimate of mean linear intercept (260 ± 27 µm) was significantly elevated as compared to the results previously reported in younger never-smokers (210 ± 30 µm), and trended smaller than in the age-matched ex-smokers (320 ± 72 µm, P = 0.06) evaluated here. Never-smokers also reported significantly smaller internal (220 ± 24 µm, P = 0.01) acinar radius but greater alveolar sheath thickness (120 ± 4 µm, P < 0.0001) than ex-smokers. Never-smokers were also significantly different than ex-smokers without emphysema for alveolar sheath thickness but not ADC, while ex-smokers with emphysema reported significantly different ADC but not alveolar sheath thickness compared to ex-smokers without CT evidence of emphysema. Differences in alveolar measurements in never- and ex-smokers demonstrate the sensitivity of MRI measurements to the different effects of smoking and aging on acinar morphometry.

Meat lipid profiles: a comparison of meat from domesticated and wild Southern African animals.

BACKGROUND: The link between meat and various chronic diseases has been qualified recently, and is now accepted as being related to the amount of saturated fat present. Other work has shown differences in total lipid profiles between meat from 'wild' and 'domesticated' animals, with the 'wild' reflecting higher levels of polyunsaturated and lower saturated fat. This study assessed both meat types from South African sources. MATERIALS AND METHODS: All 'wild' meat samples were obtained fresh from a specialist restaurant. All 'domestic' samples were purchased from commercial outlets. Lipids were quantified using thin layer and gas chromatography. RESULTS: All of the domestic meats had higher saturated and lower polyunsaturated lipid levels than the wild meats. There was little difference between the phosphoglyceride, but large differences between the triacylglycerol, fractions. CONCLUSION: Meat from animals raised under intensive agricultural methods in Africa is similar to those from the rest of the world, while wild meats are markedly different.