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Dr. Tudor H. Hughes M.D., FRCR Department of Radiology University of California School of Medicine San Diego, California Bone Densitometry Interpretation.

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Presentation on theme: "Dr. Tudor H. Hughes M.D., FRCR Department of Radiology University of California School of Medicine San Diego, California Bone Densitometry Interpretation."— Presentation transcript:

1 Dr. Tudor H. Hughes M.D., FRCR Department of Radiology University of California School of Medicine San Diego, California Bone Densitometry Interpretation of DEXA

2 Osteoporosis

3 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 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: 1. The detection of osteoporosis and assessment of its severity. 2. Evaluation of perimenopausal women for the initiation of estrogen therapy. 3. Evaluation of patients with metabolic diseases that affect the skeleton. 4. 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

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

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

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

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

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/cm 2

17 DEXA x y

18 DEXA has very high accuracy (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

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 L Lines of T12. 2 cm of tissue on both sides of the spine. Spine should be straight. No metal in spine.

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

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 cm is Medium cm is Fast cm is Medium 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 8-14cm 2 in women, cm 2 in men Check left and right and state side being used in report.

43 nonIQ DPX scanning Show 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 Template Macro DEXA

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 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 1Y, 16lb gain, 5% BMD loss = significant increase in fracture risk SD = 0.1 Both between -2 and -3 SD below mean for age

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- 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

96 63F6 New Case

97 63F5

98 4

99 3

100 2

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. 163F

102 New Case

103 35F White 242lbs 62in3 New Case

104 35F White 242lbs 62in2

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. 35F White 242lbs 62in1

106 New Case

107 OGI39M 2 New Case

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

109 New Case

110 46 F4 New Case

111 Calcified bile46 F3

112 46 F Calcified bile 2

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

114 New Case

115 47F Black 2 New Case

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. 1African American 47F

117 New Case

118 49F 2Y8M gap Lx spine up, Fem neck down2 New Case

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. 149F 2Y8M gap Lx spine up, Fem neck down

120 New Case

121 Sacral agenesis T 49F2 New Case

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

123 New Case

124 Dense R femoral neck50F3 New Case

125 50F dense R femoral neck2

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. 150F dense R femoral neck

127 New Case

128 2d earlier 2d later 51F3 New Case

129 51F Barium in diverticulum from recent enema2

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. 151F Barium in diverticulum from recent enema

131 New Case

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

133 53F 51Kg 47F 59Kg 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. 16 yr later, 8Kg wt loss

135 New Case

136 60F3 New Case

137 60F OA 2

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 54M ESLD s/p transRec. repeat3 New Case

141 54M ESLD s/p transRec. repeat2 New Case

142 Report Only technical error could account for such a finding and therefore repeat study is recommended. 154M ESLD s/p trans

143 New Case

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

145 Report If all levels increase in bone density over time, it is likely a response to treatment. 176F response to Rx

146 New Case

147 85M Bil THR 3 New Case

148 85M Bil THR 2

149 Report When the lumbar spine and hips cannot be used we turn to the distal radius and use the ultradistal measurement. 185M Bil THR

150 New Case

151 DEXA 51F New Case 4

152 DEXA 51F3

153 2

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

155 New Case

156 59M2 New Case

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

158 New Case

159 50M2 New Case

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

161 New Case

162 59F4 New Case

163 59F3

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. 1High bone density 8SD 59F

166 New Case

167 62F4 New Case

168 62F3

169 2 MDP

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

171 New Case

172 76F New Case

173 76F

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

175 New Case

176 65F New Case

177 65F

178 DEXA with islet cell met to L2 65F 1Y prior 2m prior

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

180 New Case

181 44F New Case

182 44F

183 Report 5’2”, 182lbs 1

184 New Case

185 55F New Case

186 Report 155F

187

188 Report Good response to Rx 1

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

190

191

192

193

194

195

196

197

198

199 Report 1

200 Bone Densitometry DEPA Gd 153 Accuracy similar to QCT Less radiation than QCT Measures cortical and trabecular Less sensitive to early changes Affected by aortic Ca 2+

201 DPX-IQ scanning Show 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 L Lines of T12. 2 cm of tissue on both sides of the spine. Spine should be straight. No metal in spine.

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

211 nonIQ Scan Modes

212 Dr. Tudor H. Hughes M.D., FRCR Department of Radiology University of California School of Medicine San Diego, California 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 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 scan lines prior to seeing ischium. There should be little or no lesser Trochanter. Straight shaft. 25 lines or more above the Greater Trochanter.

216


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