18F-FDG PET/CT for Diagnosis of Osteosclerotic and Osteolytic Vertebral Metastatic Lesions: Comparison with Bone Scintigraphy

STUDY DESIGN: A retrospective study. PURPOSE: The aims of this study were to investigate the diagnostic value of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in PET/computed tomography (CT) in the evaluation of spinal metastatic lesions. OVERVIEW OF LITERATURE: Recent studies described limitations regarding how many lesions with abnormal 18F-FDG PET findings in the bone show corresponding morphologic abnormalities. METHODS: The subjects for this retrospective study were 227 patients with primary malignant tumors, who were suspected of having spinal metastases. They underwent combined whole-body 18F-FDG PET/CT scanning for evaluation of known neoplasms in the whole spine. 99mTc-methylene diphosphonate bone scan was performed within 2 weeks following PET/CT examinations. The final diagnosis of spinal metastasis was established by histopathological examination regarding bone biopsy or magnetic resonance imaging (MRI) findings, and follow-up MRI, CT and 18F-FDG PET for extensively wide lesions with subsequent progression. RESULTS: From a total of 504 spinal lesions in 227 patients, 224 lesions showed discordant image findings. For 122 metastatic lesions with confirmed diagnosis, the sensitivity/specificity of bone scan and FDG PET were 84%/21% and 89%/76%, respectively. In 102 true-positive metastatic lesions, the bone scan depicted predominantly osteosclerotic changes in 36% and osteolytic changes in 19%. In 109 true-positive lesions of FDG PET, osteolytic changes were depicted predominantly in 38% while osteosclerotic changes were portrayed in 15%. CONCLUSIONS: 18F-FDG PET in PET/CT could be used as a substitute for bone scan in the evaluation of spinal metastasis, especially for patients with spinal osteolytic lesions on CT.

ANTHROPOMETRIC AND BODY COMPOSITION CHARACTERISTICS OF SHINDESHI SUMO WRESTLERS / 体力科学

A number of investigators have been concerned with the anthropometric as well as physical characteristics of sumo wrestlers during the past several decades. However, none have attempted to determine body density and percent body fat by the most accurate technique of hydrostatic or underwater weighings. Thus, a precise quantification of body density and percent body fat for the wrestlers has not yet been obtained. Ogawa et al. (1972) have predicted the body composition of sumo wrestlers from a formula which added the triceps and subscapular skinfold thicknesses. As the regression equation used in this instance was based on samples of normal young men, it may not have great predictive accuracy when used on the exceptional population of very stout athletes.<BR>The purposes of this study were : (1) to assess the validity of percent body fat estimation by skinfold thickness measurement when compared to the hydrostatic weighing criterion method ; (2) to determine the interrelationships between anthropometric variables for use in the clear assessment of the physical characteristics of ‘Shindeshi’ sumo wrestlers ; and (3) to thereby develop a formula that would reliably predict percent body fat using skinfold thicknesses and/or anthropometric measurements in this exceptional population. The interrelationships between anthropometric and body composition variables were investigated using 35 Shindeshi sumo wrestlers, aged 15-20 years (X=16.5±1.5) .<BR>The results of the present study can be summarized as follows.<BR>1. The Shindeshi in the present study possessed physiques more developed than those tested in the past, as evidenced by Rohrer's and Ponderal Indices which were approximately 180 and 26.2, respectively. The development of body weight was particularly notable (i.e., over 100kg) .<BR>2. Percent body fat for the Shindeshi was remarkably higher than that of a normal population of the same age, with approximately seventy percent of the Shindeshi possessing more than 20% body fat and less than 1.05000 body density.<BR>3. Body density and height correlated negatively and insignificantly with almost all the variables. In contrast, correlations of body weight, circumferences, and all other variables were, in most cases, high and positive, with body weight correlating least with height. The skinfold measurement correlating best with % body fat was that taken at the thigh site (r=0.898) . The circumference measurements correlating best with % body fat were obtained at the thigh (r=0.888 and 0.831) and the abdomen (r=0 885) parts.<BR>4. Of the six formulae for estimating % body fat, Sloan's correlated best with % body fat as determined by densitometry, and best approximated the mean value of 24.5%. However, all of the equations underestimated the measured % body fat of the Shindeshi.<BR>5. When an exceptional population is being investigated, estimation of % body fat should be done with a population specific equation to ensure predictive accuracy. The following multiple regression equation (r=0.963) should, therefore, be utilized for estimation of % body fat in sumo wrestlers.<BR>Y=0.2488x<SUB>1</SUB>+0.6172x<SUB>2</SUB>-14.3962 where x<SUB>1</SUB> and x<SUB>2</SUB> are abdomen circumference and skinfold thickness at thigh, respectively.