Introduction: A scanning acoustic microscope (SAM) is an apparatus for imaging acoustic properties. This apparatus can non-invasively and rapidly evaluate the hardness of materials in the elastic region. This device s...Introduction: A scanning acoustic microscope (SAM) is an apparatus for imaging acoustic properties. This apparatus can non-invasively and rapidly evaluate the hardness of materials in the elastic region. This device shows great potential for the diagnosis of dental caries in the clinical setting. However, since the tissue elastic modulus measured using a SAM is a property of the elastic region and the Knoop hardness is a property of the plastic region, the hardness properties differ completely. Therefore, we investigated whether the acoustic impedance measured using a SAM is related to the Knoop hardness, which is used as the standard for removal of carious dentin. Method: Polished sections were prepared from 20 extracted carious wisdom teeth. The acoustic impedance and Knoop hardness were measured for each section. In addition to comparing carious and healthy dentin in SAM images, we evaluated the difference between the carious and healthy dentin in terms of the acoustic impedance and Knoop hardness. We also evaluated the correlation between the Knoop hardness and acoustic impedance. Results: The SAM images were visualized as two-dimensional color images based on the acoustic impedance values. The mean acoustic impedance of carious dentin was significantly lower than that of healthy dentin, showing a similar trend as Knoop hardness. A strong correlation was observed between the two. Discussion: The acoustic impedance values obtained through acoustic microscopy differed significantly between carious and sound dentin. Both types of dentins were visualized using two-dimensional color images. A strong correlation was observed between the acoustic impedance value, which indicates the hardness of the elastic region, and the Knoop hardness, which indicates the hardness of the plastic region. The results of the present study indicate that acoustic impedance accurately reflects the hardness of dentin.展开更多
Aims: Dilated cardiomyopathy often shows left ventricular systolic dysfunction, although histologically it always exhibits non-specific abnormality. We hypothesized that myocyte sound speed might be altered due to inc...Aims: Dilated cardiomyopathy often shows left ventricular systolic dysfunction, although histologically it always exhibits non-specific abnormality. We hypothesized that myocyte sound speed might be altered due to incomplete protein accumulation in cells. Methods and Results: Ninety eight biopsied samples were obtained from 49 patients comprising 43 with clinical dilated cardiomyopathy and 6 with hypertrophic cardiomyopathy. Sound speed was evaluated in deparaffinized 10 μm thick sections using an acoustic microscope (frequency range: 50 - 105 MHz). Conventional histology revealed 7 cases of persistent myocarditis derived from clinical dilated cardio- myopathy samples. Histology of the remaining dilated cardiomyopathy patients indicated non-specific abnormality. All hypertrophic cardiomyopathy cases exhibited myocardial disarray. Ten normal autopsied hearts were compared as controls. The sound speed of controls was 1627 ± 30m/sec. The sound speed in dilated cardiomyopathy samples (1700 ±51m/sec) was 1.045-fold faster compared to controls. The sound speed in hypertrophic cardiomyopathy samples (1734 ±51m/sec, 1.066-fold compared to controls) was faster than that of the myocarditis group (1672 ±30m/sec, 1.028-fold) (P = 0.0218). Furtheremore, desmin expression was evaluated as extent of emergence (grading 0 - 4). The desmin expression score in hypertrophic cardiomyopathy samples (2.7 ± 0.8) was significantly higher than in other groups (dilated 2.0 ± 1.4, myocarditis 1.6 ± 1.5 vs., controls 0, P ≤ 0.0001, 0.0001, 0.0129, respectively). Conclusion: Cardio-myopathy enhanced the sound speed, which correlated with the elasticity of myocytes, following the impaired compliance of left ventricle, despite the absence of histological changes. The elevation of sound speed of myocytes may be linked to cytoskeletal changes. Myocyte sound speed may be a new diagnostic tool for diagnosis of idiopathic cardiomyopathy independently of conventional histological diagnosis.展开更多
文摘Introduction: A scanning acoustic microscope (SAM) is an apparatus for imaging acoustic properties. This apparatus can non-invasively and rapidly evaluate the hardness of materials in the elastic region. This device shows great potential for the diagnosis of dental caries in the clinical setting. However, since the tissue elastic modulus measured using a SAM is a property of the elastic region and the Knoop hardness is a property of the plastic region, the hardness properties differ completely. Therefore, we investigated whether the acoustic impedance measured using a SAM is related to the Knoop hardness, which is used as the standard for removal of carious dentin. Method: Polished sections were prepared from 20 extracted carious wisdom teeth. The acoustic impedance and Knoop hardness were measured for each section. In addition to comparing carious and healthy dentin in SAM images, we evaluated the difference between the carious and healthy dentin in terms of the acoustic impedance and Knoop hardness. We also evaluated the correlation between the Knoop hardness and acoustic impedance. Results: The SAM images were visualized as two-dimensional color images based on the acoustic impedance values. The mean acoustic impedance of carious dentin was significantly lower than that of healthy dentin, showing a similar trend as Knoop hardness. A strong correlation was observed between the two. Discussion: The acoustic impedance values obtained through acoustic microscopy differed significantly between carious and sound dentin. Both types of dentins were visualized using two-dimensional color images. A strong correlation was observed between the acoustic impedance value, which indicates the hardness of the elastic region, and the Knoop hardness, which indicates the hardness of the plastic region. The results of the present study indicate that acoustic impedance accurately reflects the hardness of dentin.
文摘Aims: Dilated cardiomyopathy often shows left ventricular systolic dysfunction, although histologically it always exhibits non-specific abnormality. We hypothesized that myocyte sound speed might be altered due to incomplete protein accumulation in cells. Methods and Results: Ninety eight biopsied samples were obtained from 49 patients comprising 43 with clinical dilated cardiomyopathy and 6 with hypertrophic cardiomyopathy. Sound speed was evaluated in deparaffinized 10 μm thick sections using an acoustic microscope (frequency range: 50 - 105 MHz). Conventional histology revealed 7 cases of persistent myocarditis derived from clinical dilated cardio- myopathy samples. Histology of the remaining dilated cardiomyopathy patients indicated non-specific abnormality. All hypertrophic cardiomyopathy cases exhibited myocardial disarray. Ten normal autopsied hearts were compared as controls. The sound speed of controls was 1627 ± 30m/sec. The sound speed in dilated cardiomyopathy samples (1700 ±51m/sec) was 1.045-fold faster compared to controls. The sound speed in hypertrophic cardiomyopathy samples (1734 ±51m/sec, 1.066-fold compared to controls) was faster than that of the myocarditis group (1672 ±30m/sec, 1.028-fold) (P = 0.0218). Furtheremore, desmin expression was evaluated as extent of emergence (grading 0 - 4). The desmin expression score in hypertrophic cardiomyopathy samples (2.7 ± 0.8) was significantly higher than in other groups (dilated 2.0 ± 1.4, myocarditis 1.6 ± 1.5 vs., controls 0, P ≤ 0.0001, 0.0001, 0.0129, respectively). Conclusion: Cardio-myopathy enhanced the sound speed, which correlated with the elasticity of myocytes, following the impaired compliance of left ventricle, despite the absence of histological changes. The elevation of sound speed of myocytes may be linked to cytoskeletal changes. Myocyte sound speed may be a new diagnostic tool for diagnosis of idiopathic cardiomyopathy independently of conventional histological diagnosis.
