individuals with severe motor and intellectual disorders ( smid ) are defined as those who 
 are bedridden or able to sit , and have an intelligence quotient ( iq ) lower than 351 . thoracic deformity ( td ) secondary to severe kyphoscoliosis occurs frequently in 
 individuals with smid . this deformity restricts lung function by reducing both chest wall 
 compliance and the mechanical advantage of the respiratory muscles , eventually resulting in 
 pneumonia2 . we recently developed 2 
 protocols for the measurement of td in individuals with smid , and these protocols were 
 demonstrated to be highly reliable3 . in 
 addition , the degree of td was shown to be indicated by the differences in the ratios of the 
 anteroposterior ( ap ) to laterolateral ( ll ) diameters obtained using our protocols4 . individuals are exposed to x - rays when these protocols are used to evaluate td . further 
 evaluations of degree of td are needed to determine methods that can minimize or avoid 
 exposure to x - rays . in this study , we examined the relationship between the degree of td and 
 the angle formed in transverse plane computed tomography ( ct ) images by a line connecting 
 the sternum and the spinous process of the vertebrae at the level of the xiphisternum and a 
 perpendicular line from the floor . twenty seven individuals with smid ( 15 males and 12 females ) , who were treated at 
 nishiotaru hospital , were the subjects of this study . patients were included if they had 
 previously undergone chest ct ( asteion tsx-021b , toshiba , japan ) for the diagnosis of 
 pneumonia . the mean age of the patients was 32.3  years ( sd = 21.0  years ; range , 481 years ) . ethical approval was granted by nishiotaru hospital , and informed consent was obtained from 
 the parents or guardians of all the subjects . ct images of the thorax in the transverse plane at the level of the xiphisternum were saved 
 as digital images of each patient on a personal computer . two protocols were used to measure 
 both the ap and ll diameters . in protocol 1 , microsoft powerpoint 2007 ( pp ; microsoft corp . , redmond , wa , 
 usapp ) was used to display a digital image of the thorax in the transverse plane , and a 
 rectangle was drawn on the image . the rectangular length was matched to the largest ap 
 diameter , and the width was matched to the largest ll diameter ( fig . 1 . left : protocol 1 for measuring anteroposterior ( a  b ) and laterolateral ( b  c ) 
 diameter . right : protocol 2 for measuring anteroposterior ( a  b ) and laterolateral ( a  d 
 plus b the digital image and rectangle were grouped and saved as a picture in the 
 jpeg image file format . the public domain image processing program , imagej , was 
 used to measure the rectangular length and width of the ap and ll diameters .   left : protocol 1 for measuring anteroposterior ( a  b ) and laterolateral ( b  c ) 
 diameter . right : protocol 2 for measuring anteroposterior ( a  b ) and laterolateral ( a  d 
 plus b c ) diameter in protocol 2 , pp was used to display a digital image of the thorax in the transverse 
 plane . after a grid was superimposed on the slide , vertical and horizontal lines were drawn 
 along the grid lines . these lines were grouped as the perpendicular bisector , which was 
 matched to the inclination and size of the sternum to indicate its midpoint ( fig . 2fig . 2 . left : the perpendicular bisector was matched to inclination and the size of sternum 
 to indicate the midpoint of the sternum . right : a line connecting the midpoint of the 
 sternum ( a ) with the spinous process of the vertebra ( b ) was drawn . a line was drawn connecting the midpoint of the sternum with the tip of the 
 spinous process of the vertebrae at the level of the xiphisternum in the transverse image 
 ( fig . after drawing two rectangles , 
 the right side of one rectangle length and the left side of the other were matched to the 
 connecting line . the rectangular length of each side was determined as the largest ap 
 diameter of the side , and the rectangular width of each side was determined as the largest 
 ll diameter of the side ( fig . the digital 
 image , perpendicular bisector , and rectangles were grouped and saved in the jpeg format . the length obtained by adding the right rectangular side ( the length between a and d in 
 fig . 1-right ) to the left side ( the length 
 between b and c in fig . .   left : the perpendicular bisector was matched to inclination and the size of sternum 
 to indicate the midpoint of the sternum . right : a line connecting the midpoint of the 
 sternum ( a ) with the spinous process of the vertebra ( b ) was drawn . in addition , the 
 difference between the ratios of protocols 1 and 2 ( difference ) was calculated as : the 
 difference difference = ratio of protocol 2  ratio of protocol 
 1 . imagej was used to measure the angle between the line which connecting the 
 midpoint of the sternum with the tip of the spinous process of the vertebrae ( fig . 2-right ) and a perpendicular line from the floor 
 ( angle ) . the shapiro -wilk test was used to test the normality of the data . the data were not 
 normally distributed , therefore , spearman s rank correlation coefficient was used to examine 
 whether difference and angle were related . and the statistical program r , 
 version 2.8.1 ( r foundation for statistical computing , http://www.r-project.org/ ) , was used 
 to perform all statistical analyses . the results are shown in table 1table 1 . the relationship between the difference of the two ratio protocols and the angle 
 formed by the perpendicular and a line joining the sternum and the spinous process of 
 the vertebrae at the level of the xiphisternum in the transverse imagedifferenceangle average  sdrangeaverage  sdrangers0.115  0.1580.0730.50010.3  9.00.1233.10.59difference : the difference = the ratio of protocol 2  the ratio of protocol 1 . 
 angle ; between a line which was drawn connecting the midpoint of the sternum with the 
 tip of the spinous process of the vertebrae at the level of the xiphisternum in the 
 transverse image and perpendicular line to the floor . sd : standard deviation , rs : the 
 spearman rank coefficient of correlation . * : p<0.05 . difference : the difference = the ratio of protocol 2  the ratio of protocol 1 . 
 angle ; between a line which was drawn connecting the midpoint of the sternum with the 
 tip of the spinous process of the vertebrae at the level of the xiphisternum in the 
 transverse image and perpendicular line to the floor . * : p<0.05 difference and angle were not normally distributed , therefore , spearman s rank correlation 
 coefficient was used for the analysis . the correlation between difference and angle was 
 moderate to good5 ( rs=0.59 , 
 p<0.05 ) . we examined the relationship between the degree of td , determined by the difference in the 
 ratios obtained using 2 measurement protocols , termed difference in this study , and the 
 angle from the perpendicular formed by a line connecting the sternum and spinous process of 
 the vertebrae at the level of the xiphisternum in the transverse plane ct images , termed 
 angle in this study . moderate to good5 
 correlation was found , and the degree of td increased with increasing angle . both these conditions affect thoracic 
 function and growth and have adverse effects on the function and growth of the lungs7 . td restricts lung function by reducing both 
 chest wall compliance and the mechanical advantage of respiratory muscles , and eventually 
 resulting in pneumonia1 . the most common 
 cause of death among japanese with smid is pneumonia / bronchitis ( 25.9% ) , followed by 
 respiratory diseases ( 16.0%)1 . we recently devised 2 protocols to measure 
 td in the transverse plane and demonstrated that they are highly reliable3 . in addition , we demonstrated that 
 difference is related to the degree of td4 . however , individuals can not be evaluated frequently because they would be 
 exposed to excessive amounts of x - ray radiation when the 2 protocols are used to evaluate 
 td . considering this problem , we investigated a method for the evaluation of the degree of td 
 that would not require exposure to x - rays . the method was evaluated by investigating the 
 relationship between angle and the value of difference . because the xiphisternum and the 
 spinous process of the vertebrae can be palpated easily on the body surface , angle can be 
 measured by using direct anthropometric measurement , non - invasively . our study showed that 
 the correlation between difference and angle was moderate to good and that difference 
 increased with angle . these results suggest that angle can be used as an indicator of the 
 degree of td . to evaluate angle without exposure to x - rays , the degree of td further 
 investigations to devise a method for direct anthropometric measurement of angle are 
 needed .
[ purpose ] the purpose of this study was to examine the relationship between the degree 
 of thoracic deformity ( td ) and the angle formed by a line drawn on transverse plane 
 computed tomography ( ct ) images , connecting the sternum and the spinous process of the 
 vertebrae at the level of the xiphisternum , and the perpendicular line from the floor 
 ( angle ) , in individuals with severe motor and intellectual disorders ( smid ) . 
 [ subjects ] 
 twenty seven individuals with smid were examined . [ methods ] ct transverse images were 
 acquired at the level of the xiphisternum of each patient . 
 two protocols were used to 
 measure the anteroposterior ( ap ) and laterolateral ( ll ) diameters . 
 the largest ap 
 diameters were measured along a perpendicular line from the floor ( protocol 1 ) and the 
 line from the midline of the sternum to the spinous process of the vertebrae ( protocol 2 ) . 
 the largest ll diameters were measured along the lines perpendicular to the ap diameters 
 in each protocol . the ratios of the ap to ll diameters and the difference between the 
 ratios of protocols 1 and 2 ( difference ) were calculated . [ results ] moderate to good 
 correlation between difference and angle was observed , and difference became larger with 
 increasing angle . 
 [ conclusions ] these results show that angle indicates the degree of 
 td .