EVOLUTION OF BONE DENSITOMETRY        NOVEL DXA USES          M h 8th, 2012          March    ISCD 2012: Los Angeles, CA  ...
TYPES OF FAT  Apple shape vs. Pear shape                                                  Subcutaneous Adipose Tissue (SAT...
VISCERAL ADIPOSE TISSUE (VAT)• VAT (fat in and around  abdominal organs) has been  shown to be a risk factor for all  caus...
VISCERAL FAT AND METABOLIC RISK                   Key Points                Recent study of more than 3000               ...
VisceralAdiposeTissueSubcutaneous      ResidualAdipose             TissueTissueTiss e         Compartment
WHOLE-BODYWHOLE BODY MRI ANALYSIS
Visceral  Adipose  Tissue                             MuscleSubcutaneous                             TissueAdiposeTissue  ...
Visceral       Adipose       Tissue                                Muscle                                TissueSubcutaneou...
RELIABILITY MEASURE FOR MRI                    ICC    CV Skeletal Muscle    0.99   2-5% Subcutaneous AT    0.99   2-5% Vis...
SENSITIVITY MEASURE FOR MRIMRI    Baseline         ase e     S of                   SD o      Individual                  ...
MRI Analysis    •Tissues were segmented     by trained technicians using     commercially available     image analysis sof...
The % difference between Vgap and Vtrue was      generally smaller with the decrease of gap size                    2 cm g...
Pearson correlations between VAT volume and        VAT areas for individual transverse slices                             ...
Group                                        Glu       Insulin       TG         HDL         SBP        DBPMen           Ab...
How CoreScan works•    Key Differentiator: Separates out SAT and VAT1. Start with total fat      iDXA distinguishes betwe...
CoreScan: Reproducible• Defined region of measurement ‐ Android• Automated definition of region – based off  Automated def...
CoreScan: Reproducible            Android RegionStandard region of interest for iDXA body composition    pBase of the RO...
CoreScan: Accuracy   • Validated in clinical trial*   • High degree of correlation with CT   • On average difference betwe...
CoreScan: Accuracy                                         Analysis on OHSU Data                                          ...
SUMMARY• Further studies are needed to determine  whether VF estimation offers incremental  value to other more standard m...
VISCERAL ADIPOSE TISSUE
VISCERAL ADIPOSE TISSUE (VAT)            ROI DEFINITIONRegions are automatically placed by the software•Outer region exten...
DXA VAT vs. VAT by CT                                   y                                                                 ...
CONCLUSION• If these findings are supported by similar  results in other populations, DXA-VAT  may become a useful alterna...
SUMMARY OF NEW   BODY COMPOSITION FEATURESThe new VAT Application, reference values, andreporting enhancements should be h...
Mark PunyanityaBiomedical EngineerBi    di l E iDirector, Image Reading CenterPhone:       (646) 736-2487Email:       mark...
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
ISCD 2012 Punyanitya DXA-VAT Presentation
Upcoming SlideShare
Loading in …5
×

ISCD 2012 Punyanitya DXA-VAT Presentation

1,464 views

Published on

Visceral Adipose Tissue (fat in and around abdominal organs) has been shown to be a risk factor for all cause mortality in men. VAT is a unique, fat depot associated with metabolic risk factors (triglycerides, cholesterol, fasting glucose, hypertension) and Cardiovascular Disease. Magnetic Resonance Imaging and Computed Tomography for the quantification of VAT will be discussed, as well as slice location, spacing, and selection. The latest developments for the estimation of VAT by DXA will be covered, along with recommendations for future research and use.

0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
1,464
On SlideShare
0
From Embeds
0
Number of Embeds
35
Actions
Shares
0
Downloads
39
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

ISCD 2012 Punyanitya DXA-VAT Presentation

  1. 1. EVOLUTION OF BONE DENSITOMETRY NOVEL DXA USES M h 8th, 2012 March ISCD 2012: Los Angeles, CA Mark Punyanitya Biomedical Engineer
  2. 2. TYPES OF FAT Apple shape vs. Pear shape Subcutaneous Adipose Tissue (SAT)  S b t Subcutaneous f t found underneath the skin, fat f d d th th ki which may cause dimpling and cellulite Above the  Fat accumulated in the lower body (the pear waist shape) is subcutaneous p ) Below the waist Visceral Adipose Tissue (VAT)  Also known as, intra-abdominal fat, belly fat, beer belly, central adiposityApple shape  Visceral fat pads all internal vital organs such as Pear shape•More visceral fat •Less visceral fat stomach, kidney, heart and also pancreas•Higher risk of weight‐ •Lower risk of weight‐related health  related health   Fat in the abdominal area (the apple shape) isproblems problems largely visceral Source: GSK education material S GSK d i i l http://www.alli.co.uk/How‐alli‐works/How‐visceral‐fat‐works/  Metabolically active
  3. 3. VISCERAL ADIPOSE TISSUE (VAT)• VAT (fat in and around abdominal organs) has been shown to be a risk factor for all cause mortality in men1• VAT is a unique pathogenic fat unique, depot2 associated with metabolic risk factors (triglycerides, cholesterol, (triglycerides cholesterol fasting glucose, hypertension) and CVD 1Kuk JL, et al Visceral fat is an independent predictor of all- cause mortality in men. Obesity. 2006;14(2):336-41. 2Fox CS, et al Abdominal visceral and subcutaneous adipose tissue compartments: association with metabolic risk factors in the Framingham Heart Study. Circulation. 2007 Jul 3;116(1):39- 48.
  4. 4. VISCERAL FAT AND METABOLIC RISK Key Points  Recent study of more than 3000 participants drawn from the Framingham Heart Study showed  SAT and VAT are correlated with metabolic risk factors  VAT more strongly associated with an adverse metabolic risk profile  GR = 4.7/SD (Females)  G = 4.2/SD ( GR /S (Males) ) . Fox CS et al. (2007) Circulation 116 39-48
  5. 5. VisceralAdiposeTissueSubcutaneous ResidualAdipose TissueTissueTiss e Compartment
  6. 6. WHOLE-BODYWHOLE BODY MRI ANALYSIS
  7. 7. Visceral Adipose Tissue MuscleSubcutaneous TissueAdiposeTissue Residual Tissue Tiss e Compartment
  8. 8. Visceral Adipose Tissue Muscle TissueSubcutaneousAdiposeTissue Residual Resid al Tissue Compartment
  9. 9. RELIABILITY MEASURE FOR MRI ICC CV Skeletal Muscle 0.99 2-5% Subcutaneous AT 0.99 2-5% Visceral AT Vi l 0.95 2-5% Intermuscular AT 0.97 0 97 5 8% 5-8%
  10. 10. SENSITIVITY MEASURE FOR MRIMRI Baseline ase e S of SD o Individual d dua G oup Group(kg) (mean) changes 95% CI 95% CI (1 year) (N=20)SM 18.6 18 6 0.40 0 40 0.82 0 82 0.19 0 19TAT 26.8 1.00 2.06 0.47SAT 24.0 24 0 0.90 0 90 1.85 1 85 0.43 0 43VAT 1.9 0.20 0.41 0.09IMAT 1.08 1 08 0.10 0 10 0.21 0 21 0.05 0 05
  11. 11. MRI Analysis •Tissues were segmented  by trained technicians using  commercially available  image analysis software.  •Analysis time: 24 hours for  y subcutaneous adipose  tissue, skeletal muscle,  Visceral adipose tissue,  p , Bone+organ, Intramuscular  adipose tissue, lung.‐Shen W., et al., Curr Opin Clin Nutr Metab Care.‐2006;8:595‐601
  12. 12. The % difference between Vgap and Vtrue was generally smaller with the decrease of gap size 2 cm gap 3 cm gap 4 cm gap 5 cm gap Acquisition 40-50 minutes 35-40 minutes 30 minutes 25 minutes time Analysis a ys s 12 hours 8 hours ou s 6 5 ou s 6.5 hours 5 hours ou s time SM 0.30%±0.43% 0.41%±0.35% 0.59%±0.63% 1.04%±0.77%* * * * SAT 0.26%±0.23% 0.53%±0.45% 0.59%±0.49% 0.85%±0.86%* * * * VAT 3.14%±2.99% 5.23%±6.01% 8.14%±8.15% 9.70%±8.58%* * * * IMAT 3.06%±2.41% 4.75%±4.48% 6.93%±7.30% 9.55%±8.77%* Studies will require 2 % more subjects if every 5 cm protocol is used in 5 to 17  * * * year old subjects and 8‐10 % more subjects in 5 to 10 year old prepubertal  children for equivalent power as the continuous every‐cm protocol in measuring  hild f i l t th ti t li i VAT and IMAT. ‐ Shen W., et al., Int J Pediatric Obesity. 2010
  13. 13. Pearson correlations between VAT volume and VAT areas for individual transverse slices Correlation Coefficients -10 cm -5 cm L4-L5 + 5 cm + 10 cm + 15 cmMen Abdominal VAT 0.843 0.899 0.951 0.966 0.924 Abdominopelvic VAT 0.857 0.889 0.919 0.950 0.961 0.917Women Abdominal VAT 0.908 0.929 0.972 0.961 0.822 Abdominopelvic VAT 0.856 0.930 0.936 0.964 0.951 0.821 ‐ Shen W et al., Am J Clin Nutr 2004;80:271‐8
  14. 14. Group Glu Insulin TG HDL SBP DBPMen Abdominal VAT .211 .505 .361 -.242 .312 .318(n= 283) Abdominopelvic VAT .217 .522 .356 -.255 .309 .316 -5 cm .186 .389** .272** -.194 .244** .264 L4-L5 .193 .384** .276** -.162** .277 .266** +5 cm .187 .458** .354 -.235 .307 .306 +10 cm 10 .210 .520 .401 .401* -.271* .271 .306 .313 +15 cm .201 .522 .332 -.238 .295 .313Women Abdominal VAT .218 .569 .397 -.383 -.054 .104(n = 411) Abdominopelvic VAT .222 222 .558 558 .398 398 -.385 385 -.051 051 .110 110 -5 cm .192 .547 .386 -.386 -.072 .069 L4-L5 .161** .569 .369 -.350** -.054 .139 +5 cm .219 219 .562 562 .392 392 -.392 - 392 -.060 - 060 .076 076 +10 cm .230 .514** .385 -.348** -.062 .083 +15 cm .220 .467** .305** -.299** .013 .118*, significantly higher (P < 0.05) than abdominal VAT; **, significantly lower (P < 0.05) than abdominal VAT. ‐Shen W., et al., Int J Obesity, 2007,31:763‐9
  15. 15. How CoreScan works• Key Differentiator: Separates out SAT and VAT1. Start with total fat  iDXA distinguishes between fat, lean and bone through dual energy measurements  Excellent image resolution helps enable accurate tissue characterization2. Calculate SAT  Utilize iDXA to measure SAT layer thickness at sides of android region  CoreScan maps the total SAT layer around android region SAT inner wall3. Total fat – SAT = VAT SAT outer wall
  16. 16. CoreScan: Reproducible• Defined region of measurement ‐ Android• Automated definition of region – based off Automated definition of region – based off  bone landmarks on the body• Consistent method of acquisition
  17. 17. CoreScan: Reproducible Android RegionStandard region of interest for iDXA body composition pBase of the ROI located at top of pelvisHeight (H) = 20% of distance from top of pelvis to base of skull pelvis to base of skullAndroid region contains high proportion of visceral fatRelatively little bone in android region
  18. 18. CoreScan: Accuracy • Validated in clinical trial* • High degree of correlation with CT • On average difference between iDXA On average difference between iDXA  and CT ~60g • 95% of subjects were within a range of  CT image of visceral fat from  subject (42 year old male;  16‐96cm3 difference between measuring  BMI = 26.2 kg/m2) Image courtesy of Dr. Sanjiv Kaul I f D S ji K l with CT and iDXA* Kaul et al. Dual X‐Ray Absorptiometry for Quantification of Visceral Adipose Tissue. Advance online publication 26 January 2012.
  19. 19. CoreScan: Accuracy Analysis on OHSU Data OHSU CT vs. iDXA VAT Volume All Subjects 5000 Excellent Correlation* 4000 Gender SEE r2 m³) CT VA Volume (cm 3000 Females 0.960 190.5 Males 0.953 221.6 AT 2000 Combined 0.958 209.4 1000 0 0 1000 2000 3000 4000 5000 iDXA VAT Volume (cm³) data ID* Kaul et al. Dual X‐Ray Absorptiometry for Quantification of Visceral Adipose Tissue. Advance online publication 26 January 2012.
  20. 20. SUMMARY• Further studies are needed to determine whether VF estimation offers incremental value to other more standard measures of metabolic and cardiovascular risk in patients. patients
  21. 21. VISCERAL ADIPOSE TISSUE
  22. 22. VISCERAL ADIPOSE TISSUE (VAT) ROI DEFINITIONRegions are automatically placed by the software•Outer region extends across entire abdomen Outer•Middle region extends across visceral cavity includingabdominal wall•Inside region extends across visceral cavity just inside abdominalwall
  23. 23. DXA VAT vs. VAT by CT y •Linear Relation i l i •High Correlation •Low SEE vs. CT VAT by an Expert ReaderMicklesfield et al, Dual-Energy X-Ray Performs as Well as Clinical Computed Tomographyfor the Measurement of Visceral Fat, Advance online publication 12 January 2012
  24. 24. CONCLUSION• If these findings are supported by similar results in other populations, DXA-VAT may become a useful alternative to CT and MRI for the estimation of VAT in both clinical and research settings settings.
  25. 25. SUMMARY OF NEW BODY COMPOSITION FEATURESThe new VAT Application, reference values, andreporting enhancements should be helpful in the p g pevaluation of a wide variety of abnormalities involving fatmass, lean mass, and bone, for establishing entrycriteria into clinical trials and for other clinical research trials, clinical, research,and epidemiological uses.
  26. 26. Mark PunyanityaBiomedical EngineerBi di l E iDirector, Image Reading CenterPhone: (646) 736-2487Email: mark@imagereadingcenter.comWeb: www.imagereadingcenter.com www imagereadingcenter com

×