1. Interpretation of DEXA
Bone Densitometry
Interpretation of DEXA

2. Osteoporosis

3. Osteoporosis
Osteoporosis is the most common metabolic bone disorder. It has been defined by the National Institutes of Health as an age-related disorder characterized by decreased bone mass and increased susceptibility to fractures in the absence of other recognizable causes of bone loss.

4. Osteoporosis
Type 1. involutional osteoporosis affects mainly trabecular bone, occurs in women during the years after the menopause, and is related to a lack of estrogen. This is thought to account for wrist and vertebral crush fractures, which occur through areas of principally trabecular bone.
Type 2. senile involutional osteoporosis. The fractures of old age seen at the hip, proximal humerus, pelvis and asymptomatic vertebral wedge fractures. This affects both trabecular and cortical bone and represents progressive loss of bone mass from the peak around the age of years.
Secondary osteoporosis is due to an underlying medical condition, such as renal disease, malabsorption, or hormonal imbalance, or to medical treatment such as steroids or certain anticonvulsants

5. Osteoporosis Risk factors Smoking Alcohol Poor diet Lack of exercise
may be superimposed upon either involutional or secondary osteoporosis, including :
Smoking
Alcohol
Poor diet
Lack of exercise
An early menopause
Strong family history
Small frame

6. Osteoporosis
The normal rate of bone loss is 2% per year, hence 20-40% of the female bone mass is already lost by the age of 65 years of age, beginning before the menopause and accelerating afterwards

7. Osteoporosis
Osteoporosis progression over 2Y UC Steroids 59F

8. Osteoporosis
Bone mass is the major determinant of bone strength that can be measured by non-invasive techniques, and accounts for 75-85% of this parameter

9. Osteoporosis
Bone densitometry is clinically indicated for the detection and assessment of osteoporosis and for the evaluation and monitoring of several diseases and therapies. These include:
The detection of osteoporosis and assessment of its severity.
Evaluation of perimenopausal women for the initiation of estrogen therapy.
Evaluation of patients with metabolic diseases that affect the skeleton.
Monitoring of treatment and evaluation of disease course.
In addition it may be useful as an epidemiological tool and possibly in the future for screening
American Society of Bone and Mineral Research

10. Measurement

11. Osteoporosis Measurement
Plain film,
Subjective, Radiogrammetry, Osteogram
SPA
DPA
DEXA
QCT US
MRI
Quadratical equations

12. Osteoporosis Measurement
Plain film,
Subjective, Radiogrammetry, Osteogram
SPA
DPA
DEXA
QCT US
MRI
Quadratical equations

13. Osteoporosis Measurement
Plain film,
Subjective, Radiogrammetry, Osteogram
SPA
DPA
DEXA
QCT US
MRI
Quadratical equations

14. Osteoporosis Measurement
Plain film,
Subjective, Radiogrammetry, Osteogram
SPA
DPA
DEXA
QCT US
MRI
Quadratical equations

15. Osteoporosis Measurement
Plain film,
Subjective, Radiogrammetry, Osteogram
SPA
DPA
DEXA
QCT US
MRI
Quadratical equations

16. DEXA
Because photons of different energy are differentially attenuated by bone and soft-tissues, by measuring the percentage of each transmitted beam and then applying simple simultaneous equations, the absorption by bone alone and hence bone density can be calculated.
This measurement is not a true density but rather an areal density, represented in gms/cm2

17. DEXA y x

18. DEXA DEXA has very high accuracy and precision
(the difference in the measurement from a known standard)
and
precision
(observed deviation of serial measurements with time)
both short and long term
to within 1% at the hip and spine

19. DEXA DEXA is at present the most precise measurement of BMD
QCT is more sensitive to change

20. DEXA Interpretation

21. DEXA Interpretation

22. Find out as much
relevant information
as possible

23. Find out as much
relevant information
as possible

24. Spine Scan

25. Bone Densitometry DEXA spine check list
Note the age, sex, ethnicity and weight
Does this match the reference ranges?
Is the bottom of L4 roughly at the level of the iliac crests
Are there any ribs on L1
Scoliosis
Are the vertebrae correctly divided
Anything in the soft tissue

26. Vertebroplasty

27. Calcium Tablets

28. Transitional vertebrae
Wrong levels

29. Bone Densitometry DEXA spine check list
Look for significant level to level variations
15-20% difference between adjacent levels

30. DEXA, what makes a good scan?
5-15 Lines of Iliac Crest. I recommend 1/2 of L5.
5-10 Lines of T12.
2 cm of tissue on both sides of the spine.
Spine should be straight.
No metal in spine.

31. Common problems with spine scans.
Spine isn’t straight.
Scan starts in sacrum.
Scan stops too soon.
Wrong scan mode.
Scan doesn’t include L5.

32. What is a scan mode?
This determines the speed the arm travels, and how much radiation the patient receives.
The bigger the patient, the more radiation you’ll require.
The smaller the patient, the less radiation you’ll require.

33. IQ Scan Modes

34. IQ Patient Thickness 12-15 cm is Medium 750 15-22 cm is Fast 3000
Most patients fall in the Fast 3000 range.

35. Bone Densitometry
In preventing Fxs it is the worst scenario that matters.
Generally a slight increase in density as descend the L spine.
Approx 6% increase between L1 and L4.

36. Typical Spine scan

37. What’s wrong with this scan?
L1 is really T12

38. What’s wrong with this scan?
Divisions don’t account for scoliosis

39. What’s wrong with this scan?
Everything

40. Femur Scan

41. DEXA Femur check list Hints for a good scan.
Patient should be straight on table.
Pack patient with rice bags.
Shaft of femur should be straight.
Rotate leg inward, this will hide the lesser trochanter.

42. DEXA Femur check list Hints for a good scan.
The Wards area is roughly half the neck area
Trochanteric area 8-14cm2 in women, 10-16cm2 in men
Check left and right and state side being used in report.

43. nonIQ DPX scanning Show 15-30 scan lines prior to seeing ischium.
There should be little or no lesser Trochanter.
Straight shaft.
25 lines or more above the Greater Trochanter.

44. Typical Femur Scan

45. What’s wrong with this scan?
Too much shaft

46. What’s wrong with this scan?
Insufficient tissue below neck

47. What’s wrong with this scan?
Set up for wrong leg

48. What’s wrong with this scan?
Includes ischium

49. Reporting

50. Bone Densitometry WHO uses T scores
Normal
> -1 SD below young adult
Osteopenia SD
Osteoporosis
<-2.5 SD
Established (Manifest) Osteoporosis
+ Fxs, usually spine, hip, proximal humerus, wrist, rib

51. Macro DEXA
Template

52. Bone Densitometry Never round up figures
-1 is osteopenia, is normal
-2.5 is osteoporosis, is osteopenia

53. Example

54. Bone Densitometry
44F

55. Bone Densitometry
44F

56. Bone Densitometry
44F

57. Bone Densitometry
44F

58. Bone Densitometry
T score is compared to reference population, years, same sex, any race, any weight.
Z score is matched for age, sex, weight and ethnicity.

59. Two possible reasons for this lady’s Z score being
worse than the T score?

60. Two possible reasons for this lady’s Z score being
worse than the T score?
Obesity and race

61. The T score is based on a white, same sex, age 20-40 population
The T score is based on a white, same sex, age population. The patient's BMD is compared to this population's BMD. A lower T score means that the patient BMD is low compared to this young, healthy normal weight population The Z score compares the patient to an adjusted population, it adjusts for age, weight, and ethnic background. The Z score can be lower than the T score for the patient, if the average patient in this population has a higher BMD than the average in the T score population. This can be seen in patients with higher weights, (which increases bone density), and in African American groups, (which show increased bone density).
If the patients comparison group has a generally higher bone density, then it is possible to have a poorer comparison to others of same age, than to younger comparisons in generally lower density group.

62. 260 lb man, young Z above young T

63. Black as
Black as
White

64. Black as
>
Black as
White
T same
Z up
<

65. Bone Densitometry Weight gain/loss and Z
Weight gain (or loss) will not affect Z score comparison, since Z scores are weight matched, but should cause an increase (or decrease) in absolute BMD.
An increase in weight, pushes up the reference range, and therefore the Z score may seem reduced, and vice versa.
2.2lbs=1Kg

66. Bone Densitometry Weight gain/loss and T
Weight gain (or loss) should cause an increase (or decrease) in absolute BMD.
Weight gain (or loss) will affect T score comparison, since reference range will not have changed.
Hence an increase in weight with a corresponding increase in bone density, will look like a good improvement in T score, but fracture risk is unchanged.

67. 51F
90Kg
53F
51Kg

68. = significant increase in fracture risk
1.172
1.176
SD = Both between -2 and -3 SD below mean for age
1Y, 16lb gain, 5% BMD loss
= significant increase in fracture risk

69. Comparison with previous

70. Bone Densitometry Comparison with previous
Are the studies comparable
Always compare like with like
Thornton L1-4
4th and Lewis (previously L2-4)
Any intervening events
Cannot compare Hologic and Lunar

71. Bone Densitometry Comparison with previous
David Sartoris’s previous studies that do not mention the region or levels measured, were standardized for L1-4 and the femoral neck.
He usually did not quote BMD.
Many previous studies were prior to the current database.
Use the percent young adult as a guide to percentage change.

72. Bone Densitometry Comparison with previous
If over a period of time there is an increase in BMD in the lower lumbar spine and decrease in the upper lumbar spine, it is likely there is OA of the lower facet joints, and the upper lumbar spine is a truer reflection of useful BMD.

73. Bone Densitometry Comparison with previous
Increase in BMD of the femoral neck can be due to calcar buttressing with OA of the hip.

74. Bone Densitometry Comparison with previous
If you want to eyeball the % for a comparison, use the young adult % since the reference range will not change with age.
A static bone density is actually a good result over a significant period of time
If a test is 1% precise, then a change has to be greater than 2% to be significant

75. Bone Densitometry Comparison with previous
If you would have expected the bone density to have fallen 4% in 2 years, and it is static, then this is a positive response to RX

76. Bone Densitometry Comparison with previous
Generally Rx affects all levels equally.
OA does not.

77. Bone Densitometry Comparison with previous
55F

78. Bone Densitometry
55F

79. Bone Densitometry
55F

80. Bone Densitometry
55F

81. Children

82. Bone mass in healthy children
Radiology 1991;179:

83. Bone mass in healthy children
Increases with age, weight and pubertal Tanner stage.
Tanner stage and weight are best predictors of bone mass.
Age, sex, race, activity and diet are not good predictors, when weight and Tanner stage are controlled.
Radiology 1991;179:

84. Bone mass in healthy children
Make sure we have at least the age and weight of the child, if not the Tanner stage.
Radiology 1991;179:

85. BMD in children and adolescents

86. BMD in children and adolescents
BMD in children and adolescents- Female- L2-4- Lunar

87. BMD in children and adolescents
BMD in children and adolescents- Male- L2-4- Lunar

88. BMD in children and adolescents- Female- femur

89. BMD in children and adolescents- Male- femur

90. BMD in children and adolescents- Female- femoral neck

91. BMD in children and adolescents- Male- femoral neck

92. BMD in children and adolescents- Female- L2-4

93. BMD in children and adolescents- Male- femur

94. Cases

95. Cases

96. New Case 6
63F

97. 5
63F

98. 4
63F

99. 3
63F

100. 2
63F

101. Report
Because of the previous laminectomy at L4, which may also be affecting the reading on the inferior aspect of L3, the BMD is averaged at L1-2. Note is also made of mild decrease in the L4 vertebral height. 1
63F

102. New Case

103. New Case 3
35F White 242lbs 62in

104. 2
35F White 242lbs 62in

105. Report
Because of the patients weight, the T score may not fully represent the fracture risk, and note should be made that the Z score is 1.7 SD below age and weight matched. 1
35F White 242lbs 62in

106. New Case

107. New Case 2
OGI
39M

108. Report
The very low bone density is compatible with the known diagnosis of osteogenesis imperfecta. 1
39M

109. New Case

110. New Case 4
46 F

111. 3
Calcified bile
46 F

112. 2
46 F Calcified bile

113. Report
Although the calcified bile is seen on the DEXA scan, it is outside the measured region and will not affect the reading. 1
46 F Calcified bile

114. New Case

115. New Case
Black 2
47F

116. Report
The Z score is worse than the T score at all levels because the the Z score is compared to weight and ethnicity and African American females naturally have a higher bone density than the standard Caucasian used for the T score, even at the age of 47. 1
African American 47F

117. New Case

118. New Case 2
49F 2Y8M gap Lx spine up, Fem neck down

119. Report
A common cause for the bone density of the lumbar spine to increase whilst that of the femoral neck decreases over time is, the development of lower lumbar spine end plate sclerosis and facet osteophytes. 1
49F 2Y8M gap Lx spine up, Fem neck down

120. New Case

121. New Case T 2
Sacral agenesis
49F

122. Report
It is likely that only L1 represents close to true bone density and use of femoral neck measurements alone is recommended. 1
Sacral agenesis 49F

123. New Case

124. New Case 3
Dense R femoral neck
50F

125. 2
50F dense R femoral neck

126. Report
In view of the significant discrepancy between the right femoral neck and lumbar spine measurements , radiographs of the right hip/pelvis are recommended. 1
50F dense R femoral neck

127. New Case

128. New Case
2d earlier
2d later 3
51F

129. 2
51F Barium in diverticulum from recent enema

130. Report
It was noticed that the patient has had a recent barium study and that barium may therefore falsely elevate the bone density. A repeat study is therfore recommended. 1
51F Barium in diverticulum from recent enema

131. New Case

132. New Case
53F
51Kg
6 yr later, 8Kg wt loss
47F
59Kg 2

133. 47F
59Kg
53F
51Kg 1

134. Report
As the patient loses weight the T score worsens at a faster rate than the Z score because the reference range for the Z score also is lowered.
However with the loss of weight the fracture risk does not increase as much as the T score worsens. 1
6 yr later, 8Kg wt loss

135. New Case

136. New Case 3
60F

137. 2
60F OA

138. Report
Because of lower lumbar spine degenerative changes the lumbar spine should not be included in the study. 1
60F OA

139. New Case

140. New Case 3
Rec. repeat
54M ESLD s/p trans

141. New Case 2
Rec. repeat
54M ESLD s/p trans

142. Report
Only technical error could account for such a finding and therefore repeat study is recommended. 1
54M ESLD s/p trans

143. New Case

144. New Case
15m earlier
15m later 2
76F response to Rx

145. Report
If all levels increase in bone density over time, it is likely a response to treatment. 1
76F response to Rx

146. New Case

147. New Case 3
85M Bil THR

148. 2
85M Bil THR

149. Report
When the lumbar spine and hips cannot be used we turn to the distal radius and use the ultradistal measurement. 1
85M Bil THR

150. New Case

151. New Case 4
DEXA 51F

152. 3
DEXA 51F

153. 2
DEXA 51F

154. Report
Increase in lumbar spine bone density is due to syndesmophytes and ligament ossification. 1
Ank Spond DEXA 51F

155. New Case

156. New Case 2
59M

157. Report Calcium anterior to the spine can increase apparent BMD. 1
DEXA pancreatic Cal 59M

158. New Case

159. New Case 2
50M

160. Report
If the patient does not wish to divulge their personal details, only T score and not Z score can be produced. 1
DEXA no personal data 50M

161. New Case

162. New Case 4
59F

163. 3
59F

164. 2

165. Report
Benign bone sclerosis such as Worth’s disease or Van Buchem’s, or a variant of osteopetrosis.
Recommend repeat DEXA to check for spurious result. 1
High bone density 8SD 59F

166. New Case

167. New Case 4
62F

168. 3
62F

169. MDP 2
62F

170. Report
Benign sclerotic lesion L1
Levels may be incorrect. 1

171. New Case

172. New Case
76F

173. 76F

174. Report
When a vertebrae collapses, initially it will be of higher density. 1
DEXA L1 fracture 76F

175. New Case

176. New Case
65F

177. 65F

178. 1Y prior m prior
DEXA with islet cell met to L2 65F

179. Report
Look out for vertebrae with a different and unaccountable bone density, either higher or lower. 1
DEXA with islet cell met to L2 65F

180. New Case

181. New Case
44F

182. 44F

183. Report
5’2”, 182lbs 1

184. New Case

185. New Case
55F

186. Report 1
55F

187. 55F

188. Report
Good response to Rx 1

189. New Case
54yo F with h/o pancreatic neuroendocrine tumor and small cell lymphoma on Fosamax

197. New Case

199. Report 1

200. Bone Densitometry DEPA
Gd153
Accuracy similar to QCT
Less radiation than QCT
Measures cortical and trabecular
Less sensitive to early changes
Affected by aortic Ca2+

201. DPX-IQ scanning Show 25-40 scan lines prior to seeing ischium.
There should be little or no lesser Trochanter.
Straight shaft.
25 lines or more above Greater Trochanter.

202. Bone Densitometry QCT Single energy 97% accurate
Dual energy not routinely available
300mR
Fat content adversely affects accuracy
Difficult to reproduce positioning
Can only measure trabecular bone
8X increase turnover of trabecular bone

203. IQ has version 4.3 and above

204. Non IQ has these versions
Version 1.15 for the DPXalpha
Version 1.35 for the DPXL
Version 3.65 for the DPX
Version 1.15 for the DPXSF
Can upgrade with the 3.65 u on all versions.

205. DPXIQ versus DPXnonIQ Spine measure and analysis are the same.
Scan modes vary depending on the type of DPX.
Femur measuring is different.
Femur analyzing is different.
IQ and nonIQ are different animals.

206. How is IQ different? IQ offers unlimited patients in database
IQ offers Total Femur results, as well as Femoral Neck.
IQ offers better resolution image.
IQ offers automatic analysis of femurs.
IQ offers better algorithms for femurs.

207. How is nonIQ different? Limited patients in database (3500 to 7500).
Offers only Femoral Neck
Resolution is not nearly as good.
Must manually analyze all femurs.
Algorithms not as good for femurs.

208. SPINE SCANS FOR ALL TYPES OF DPX

209. IQ and non IQ, what makes a good scan?
5-15 Lines of Iliac Crest. I recommend 1/2 of L5.
5-10 Lines of T12.
2 cm of tissue on both sides of the spine.
Spine should be straight.
No metal in spine.

210. Common problems with spine scans.
Spine isn’t straight.
Scan starts in sacrum.
Scan stops too soon.
Wrong scan mode.
Scan doesn’t include L5.

211. nonIQ Scan Modes

212. Femur scans for DPX-IQ

213. Hints for a good scan. Patient should be straight on table.
Pack patient with rice bags.
Shaft of femur should be straight.
Rotate leg inward, this will hide the lesser Trochanter.

214. DPX-IQ scanning Show 25-40 scan lines prior to seeing ischium.
There should be little or no lesser Trochanter.
Straight shaft.
25 lines or more above Greater Trochanter.

215. nonIQ DPX scanning Show 15-30 scan lines prior to seeing ischium.
There should be little or no lesser Trochanter.
Straight shaft.
25 lines or more above the Greater Trochanter.