Yasutaka Takubo

Optimized scanning conditions of high resolution CT in the follow-up of pulmonary emphysema

PURPOSE To address the optimal scanning condition of high resolution computerized tomography from the perspective of minimizing exposed dose. METHOD The influence of the electric current, the slice number, and the slice thickness on precise percent ratio of the low attenuation area to whole lung field (LAA%) of chronic obstructive pulmonary disease patients was examined. The standard conditions were 250 mA, 3 slices, 2 mm slice thickness, and a varied parameter. RESULTS In cases showing an LAA% less than 30, LAA% obtained by < or =150 mA were significantly larger than those by 250 mA. The mean LAA% with 3 and 10 slices were well correlated and the correlation with lung function was similar. The correlation of LAA% with lung function was approximately the same between the 2 and 5 mm slice thicknesses. CONCLUSION The electrical current must be > or =200 mA, and 3 slices and 2 mm slice thickness are appropriate.

AGE-ASSOCIATED CHANGES IN ELASTIN AND COLLAGEN CONTENT AND THE PROPORTION OF TYPES I AND III COLLAGEN IN THE LUNGS OF MICE

We investigated the effect of aging on the extracellular matrix of the lungs by examining age-associated changes in the elastin and collagen content, and the proportion of types I and III collagen, in the whole lungs of BALB/c and SAMR1 male mice between the ages of 3 and 24 months. The elastin content was determined by the hot alkali method. The hydroxyproline content was measured and assessed to be the collagen content. The relative proportion of types I and III collagen was assessed by cyanogen bromide digestion, followed by separation of the resultant peptides by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The elastin content did not change significantly with age in either strain of mice. The total collagen content of the whole lung was significantly higher at 24 months of age, although there were no significant changes with aging in the hydroxyproline content per dry lung weight nor in the proportion of type III to type I collagen. We conclude that in terms of the extracellular matrix, the lungs of aged mice are not very different in feature from the lungs of younger mice, and this is probably the simple consequence of growth of the lungs of young mice.

Age-related changes in the static and dynamic mechanical properties of mouse lungs.

To investigate the effects of aging on pulmonary mechanical properties in mice, we devised a new experimental apparatus to measure the respiratory impedance of excised lungs in mice and examined age-related changes in both static and dynamic properties. In an accelerated senescence-resistant strain of mice, SAMR1 (Takeda, T., Y. Fukuchi, Y. Uejima, K. Teramoto, T. Oka and H. Orino, J. Am. Geriatr. Soc. 39: 911-919, 1991), ranging from 3 to 24 months of age, static compliance (Cst) as well as total lung capacity increased significantly with age, whereas specific compliance and the K value, as determined by exponential analysis, showed no significant change. In the dynamic study, dynamic compliance (Cdyn) increased significantly with age, whereas the frequency dependence of Cdyn (Cdyn/Cst) did not vary with age. From these results we concluded that lung elasticity, normalized to lung volume, remained constant with age and that the effects of aging on pulmonary mechanics might be solely derived from increases in lung volume in the SAMR1 strain of mice.

Distorted Trachea in Patients with Chronic Obstructive Pulmonary Disease

Background and Objectives: We evaluated the size and configuration of the trachea in patients with chronic obstructive pulmonary disease (COPD; n = 35) on high-resolution computed tomography (HRCT) images and compared them with those of healthy volunteers (n = 24). Methods: Using a newly developed computed method for analyzing the digital data of HRCT, the size and configuration of the trachea were automatically evaluated. Results: The size of the trachea of the COPD subjects was the same as that of the control subjects; however, the configuration was more distorted in the COPD patients. There was no difference in the tracheal index (TI), which is the ratio of the coronal to the sagittal length, between these two groups; however, the ratio of the short to the long radius (SR/LR) was significantly smaller in the COPD group than in the control group. There was a significant correlation between SR/LR and airflow limitation as assessed by pulmonary function tests in the COPD group. Conclusions: The SR/LR is a better index of tracheal deformity than the classical TI. This deformity is not a consequence secondary to hyperinflation or emphysematous change of the lung, because the low attenuation area of the lung was not correlated with SR/LR.

Age-Related Changes in the Trachea in Healthy Adults

To investigate age-related changes in the shape of trachea, normal male volunteers (n = 83, mean +/- SD: 47.7 +/- 20.2 years old) underwent inspiratory CT scans at full inspiration and lung function tests. Subjects who showed VC < 80% predicted or FEV1 < 80% predicted on lung function tests were excluded. The CT data, which is located at 2.0 cm above the aortic arch, were transferred to a personal computer. The tracheal area (St) and two parameters, Tracheal index (Ti) and Circularity (Ci) indicating the shape of the trachea, were automatically calculated. Ti was defined the ratio of the coronal to the sagittal diameter of the trachea, and the Ci (Ci = 4piS/L2, S: tracheal area, L: tracheal perimeter) was used to indicate the roundness of the trachea. A Ci value of less than 1 indicated the distortion of the roundness. Both St and St/BSA (body surface area) showed a significant correlation with age (r = 0.37, r = 0.52; p = 0.0006, p < 0.0001). Ti was not correlated with age (r = -0.20; p = 0.0697), whereas Ci was significantly correlated with age (r = -0.32; p = 0.00364). There were measurable age related changes of the trachea both in the area and the shape. Aging results in the increased tracheal area and a distortion of the roundness.

A novel germline mutation in a patient with nevoid basal cell carcinoma syndrome showing cystic lesion in the lung

Nevoid basal cell carcinoma syndrome (NBCCS) manifests multiple defects involving the skin, endocrine and nervous systems, eyes and bones. Mutations in the patched homologue 1 (PTCH1) gene are the underlying causes of NBCCS, leading to aberrant cell proliferation through constitutive activation of the hedgehog signaling pathway. We identified a novel frameshift mutation (c.1207dupT) of PTCH1 in a NBCCS patient, which might explain multiple cystic lesions and neoplastic growth in the patient.