ABSTRACT
This study aimed to characterise viscoelastic properties of different categories of chordae tendineae over a range of frequencies. Dynamic Mechanical Analysis (DMA) was performed using a materials testing machine. Chordae (n=51) were dissected from seven porcine hearts and categorised as basal, marginal, strut or commissural. Chordae were loaded under a sinusoidally varying tensile load at a range of frequencies between 0.5 and 5Hz, both at a standardised load (i.e. same mean load of 4N for all chordae) and under chordal specific loading (i.e. based on in vivo loads for different chordae). Storage modulus and stiffness were frequency-dependent. Loss modulus and stiffness were frequency-independent. Storage and loss moduli, but not stiffness, decreased with chordal diameter. Therefore, strut chordae have the lowest moduli and marginal chordae the highest moduli. The hierarchy of dynamic storage and loss moduli is: marginal, commissural, basal and strut. In conclusion, viscoelastic properties of chordae are dependent on both frequency and chordal type. Future/novel replacement chordal materials should account for frequency and diameter dependent viscoelastic properties of chordae tendineae.
Subject(s)
Chordae Tendineae/anatomy & histology , Elasticity , Materials Testing , Mitral Valve/anatomy & histology , Animals , Biomechanical Phenomena , Chordae Tendineae/physiology , Humans , Mitral Valve/physiology , Swine , Tensile Strength , Viscosity , Weight-BearingABSTRACT
High resolution computed tomography (HRCT) has considerably improved the ability to diagnose and characterize interstitial lung disease (ILD). This paper assesses the role of HRCT in evaluating small airway disease associated with ILD particularly sarcoidosis, hypersensitivity pneumonitis, and interstitial pulmonary fibrosis.
Subject(s)
Lung Diseases, Interstitial/diagnostic imaging , Lung Diseases, Interstitial/pathology , Pulmonary Alveoli/diagnostic imaging , Pulmonary Alveoli/pathology , Tomography, X-Ray Computed/methods , Alveolitis, Extrinsic Allergic/diagnostic imaging , Alveolitis, Extrinsic Allergic/pathology , Female , Humans , Male , Pulmonary Fibrosis/diagnostic imaging , Pulmonary Fibrosis/pathology , Sarcoidosis, Pulmonary/diagnostic imaging , Sarcoidosis, Pulmonary/pathology , Sensitivity and SpecificityABSTRACT
Recently, with radiology some advances have been made in the care of patients with interstitial lung disease, predominately through the use of high-resolution computed tomography. This technique is helpful not only in the diagnosis of interstitial lung disease, but also in patient follow-up and management. Other techniques, including nuclear medicine and magnetic resonance imaging, have limited but well-defined uses. Positron emission tomography is a promising nuclear medicine technique, but its benefits have not been substantiated in the literature.
Subject(s)
Diagnostic Imaging , Lung Diseases, Interstitial/diagnosis , Follow-Up Studies , Humans , Lung Diseases, Interstitial/diagnostic imaging , Magnetic Resonance Imaging , Radiopharmaceuticals , Tomography, Emission-Computed , Tomography, X-Ray Computed/methodsABSTRACT
The purpose of this study was to illustrate high-resolution computed tomography (HRCT) findings in symptomatic adult Gaucher's disease patients. Five adult patients with Gaucher's disease experienced dyspnea. These patient were first evaluated by chest X-ray (CXR) followed by HRCT. The chest X-ray on one patient demonstrated a calcified granuloma. Two patients had interstitial disease only seen on HRCT, and two patients had a combination of interstitial and alveolar disease giving a mosaic pattern better illustrated on HRCT. HRCT can be used following CXR to evaluate lung pathology in symptomatic adult Gaucher's disease patients.
