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Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry
ARTICLE IN PRESS The Egyptian Journal of Radiology and Nuclear Medicine (2016) xxx, xxx–xxx
Egyptian Society of Radiology and Nuclear Medicine
The Egyptian Journal of Radiology and Nuclear Medicine www.elsevier.com/locate/ejrnm www.sciencedirect.com
ORIGINAL ARTICLE
Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry Jalil Pirayesh Islamian a, Islam Garoosi b,*, Kourosh Abdollahi Fard c, Mohammad R. Abdollahi c a
Immunology Research Center in Tabriz University of Medical Sciences, Tabriz, Iran International Branch of Tabriz University of Medical Sciences (Aras), Jolfa, Iran c Private Medical Imaging Centre of Nova, Maragheh, Iran b
Received 12 April 2015; accepted 3 April 2016 Available online xxxx
KEYWORDS Bone mineral density; Computed tomography; Dual-energy X-ray absorptiometry; Hydroxyapatite; Osteoporosis
Abstract Purpose: To determine the bone mineral density of lumbar spine vertebrae by generating computerized tomography (CT) densitometric data based on the Hounsfield units (HU) from abdominal and lumbar spine CT examinations. Material and methods: All the CT examinations were performed with a 16-slice CT system. A designed phantom of the gelatin solubilized hydroxyapatite, simulating the spine, was used for phantom studies. Sixty-one patients who underwent the abdominal CTs and also the following dual-energy X-ray absorptiometry examinations were evaluated. Results: The diagnosed cases of osteoporotic, osteopenic and normal bone densities were obtained 42.9%, 32.1%, 25% by multi-detector CT and 21.4%, 53.6%, 25% by dual-energy X-ray absorptiometry examinations for the 61 subjects, respectively. Using a trabecular ROI, a threshold of 155 HU at the L1 spine level yields a 100% sensitivity for osteoporosis and a threshold of 115 HU was shown more than 90% specificity for differentiating osteoporosis from osteopenia and also a normal bone mineral density. Conclusions: Bone mineral density values derived from the routine abdominal and lumbar spine multi-detector CT examinations may also be used for the population osteoporosis screening. Ó 2016 The Egyptian Society of Radiology and Nuclear Medicine. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
1. Introduction
* Corresponding author. Tel.: +98 9141490690. E-mail address: [email protected] (I. Garoosi). Peer review under responsibility of The Egyptian Society of Radiology and Nuclear Medicine.
Bone density is the amount of bone tissue in a certain volume of the bone (1). It is often very difficult to establish the measure with a non-invasive approach. Therefore, the term bone mineral density (BMD) is conventionally used instead, so that
http://dx.doi.org/10.1016/j.ejrnm.2016.04.005 0378-603X Ó 2016 The Egyptian Society of Radiology and Nuclear Medicine. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
ARTICLE IN PRESS 2 BMD is the most important determinant of bone fragility in evaluation of osteoporosis (2). Patients with a reduced bone mineral density have an increased risk of bone fracture (3), particularly at hip (4) and spine (5). BMD can be measured in a variety of skeletal regions and techniques (6). Dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) of the lumbar spine were considered as preferred methods for evaluation of BMD. DXA was recommended by the World Health Organization (WHO) as a gold standard for diagnosing osteoporosis. Because of its availability, related minimal radiation exposure and simplicity of use, DXA is the most commonly employed quantitative radiologic method to assess the bone mass (7). However, DXA has some pertinent disadvantages that are needed to be considered: (a) It is a two-dimensional measurement, which only measures density/area (in g/cm2). (b) The DXA of hip and spine is also sensitive to underestimate in cases such as degenerative changes that have an increased local densities (8). In a recent study on DXA pitfalls by Messina et al. (9), authors reported a high rate of errors in DXA estimations. They found that more than 90% of DXA examinations, performed in clinical practice, were affected by at least one error, and 79% of the errors were related to an inappropriate analysis during the related image processing phenomena. QCT has grown from its initial development in the 1970s to become an established technique to assess skeletal status, response to the therapy for osteoporosis and also other metabolic bone diseases. It is widely accepted that QCT is the most sensitive method available to detect osteoporosis (10,11). It is unique among the current noninvasive approaches to the bone mineral measurements as it measures true three-dimensional BMD as opposed to the area (two-dimensional) density measures obtained from some protection techniques. By QCT, it can measure the trabecular, the cortical or the integral bone, centrally or peripherally. Although this technique has some important advantages over DXA, BMD values depend on bone marrow composition so it may underestimate the bone mineral content. The radiation dose delivered by a QCT scan is significantly higher than DXA (200 lSv vs 15 lSv) (12), which limits the technique not only for population screening but also for the conventional diagnostics. Additionally, the technique has a high degree of operator dependency, limited access to the scanners, a high cost examination as compared to DXA, complexity in quality control and necessity to a well-trained operator for a scan execution (12–16). Hence the DXA is still the technique of choice. When osteoporosis is a prevalent and treatable disease and conveys a considerable fracture risk, yet it remains substantially under diagnosed and undertreated (17–20). Safe and cost-effective alternatives are needed to increase the related detection rates. Abdominal CT is one of the most frequently used diagnostic examinations. Retrieval of BMD data available on body CT examinations, ordered for other indications, requires no additional costs, no patient scanning or additional radiation exposures, and the related data can be retrospectively achieved. It could therefore expand the population screening efforts for osteoporosis. 2. Aims and objectives The objective of this study was to determine the bone mineral density of lumbar spine (L1–L4) vertebrae by generating CT
J. Pirayesh Islamian et al. densitometric data based on Hounsfield units from routine abdominal and lumbar spine MDCT examinations and comparing with those of DXA scanners and investigate whether these data can be used to suitably differentiate osteoporotic, osteopenic or normal bone density conditions. 3. Materials and methods This retrospective single-institute study, approved by the institutional review board, was conducted in accordance with the ethical standards of the Declaration of Helsinki. The designed phantom simulating the spine of a human, was filled from the gelatin solubilized of 60, 80,100, 120, 140 mg/cm3 hydroxyapatite, placed in the ‘‘spine” region in a water filled polyethylene container (Fig. 1). Also, there are no documented standards for assigning diagnostic categories based on the QCT spine BMD measurements, according to American College of Radiology (ACR) recommendations (21) and the suggestions by International Society for Clinical Densitometry (ISCD) in 2007 (22) and the following category definitions were considered for the QCT of the spine BMD measurements similar to the WHO diagnostic categories that are used to hip BMD measurements. The patient category definitions are also based on the actual volumetric BMD with a threshold of 120 mg/cm3 for osteopenia (a DXA T-score of 1.0) and 80 mg/cm3 for osteoporosis (a DXA T-score of 2.5). In 2007, ISCD has developed some official positions for the clinical use of DXA and non-DXA technologies, which point out that a single-slice spinal QCT should include the vertebral bodies of L1–L3, and also a 3D QCT should include L1–L2 (22). In addition, T12 or L3–L4 are usually suggested as the alternative vertebral bodies in cases that the included one is not eligible for the measurement (23). The BMD of the designed phantom was included for the related densities of normal, osteopenia and osteoporosis. For phantom study, after daily routine calibration of the CT scanner as per manufacturer’s recommendations, the designed phantom was scanned with a 16-slice CT system (Toshiba Alexion Advance Edition 16, Japan). Also, sixty-one patients (38 females and 23 males with a mean age of 60.2 years) who underwent a trunk CT and also the following DXA examination, due to a suspected osteoporosis from a weak damaged trauma and bone densitometry were evaluated. Patients with a history of CT scanning for a non-contrast abdominal or a weak damaged trauma on the lumbar spine and the followed DXA for bone densitometry in an interval of two months after CT scanning were also included in our study. The patients under 50-years old and also those with an apparent bone fracture were excluded. A routine abdominal MDCT protocol was used for the both phantom and patient study. The CT parameters were included: a tube voltage of 120 kVp, a tube current of 160 mA s, the beam collimation size of 16 1 mm, a pitch factor of 0.938 mm, an imaging slice of 5 mm, and a bone reconstruction algorithm with a window width 1500, in a window level of 300. The related two dimensional reconstructions were obtained in a sagittal plane. A 20 10 mm ROI of elliptical shape ROI was located in middle trabecular of the vertebral body for the phantom less condition (Fig. 2). All the DXA measures were done with a Hologic Explorer densitometer (USA). Information from DXA scans, including
Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
ARTICLE IN PRESS Evaluation of BMD in the lumbar spine densitometry
3
Fig. 1 Scanning position of a homemade lumbar vertebrae phantom (A) in a water filed polyethylene container, as torso region of a human. (B) The hydroxyapatite concentrations were set to 60, 80, 100, 120, and 140 (mg/cm3) for vertebrae phantom 1, 2, 3, 4 and 5, respectively.
T-scores and bone mineral densities (in g/cm2), was obtained from L1 to L4 lumbar vertebrae.
were calculated according to the L1–L4 HUs. All statistical tests were two sided and performed at a significant level of p < 0.05.
4. Statistical analysis
5. Results
The Statistical Analysis was carried out using Statistical Package for Social Sciences (SPSS) software, Version 21.0. The correlation parameters between DXA and abdominal and lumbar MDCTs
The designed phantom allowed to calibrate a MDCT system as a technique in determination of spinal BMD. The data on mean HU of the phantom for MDCT were obtained 75, 101,
Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
ARTICLE IN PRESS 4
J. Pirayesh Islamian et al.
Fig. 2 Computed tomography scans illustrating calculation of the vertebral BMD based on Hounsfield units (a 56 year female). Corresponding lateral (A) and anteroposterior (B) scout images of the abdominal. (C) Axial cross-sectional images showing HU values generated with an oval ROI.
127, 153 and 177 HU, respectively for the related lumbar phantom densities 60, 80, 100, 120 and 140 (mg/cm3). The diagnosed cases of osteoporotic, osteopenic and normal bone densities from the 61 subjects undergone the MDCT were scored 42.9%, 32.1%, and 25%, respectively, and by the DXA screening approach the related diagnosis was obtained 21.4%, 53.6%, and 25%, respectively. A trabecular ROI with an attenuation threshold of 155 HU at the L1 level yields a 100% sensitivity for osteoporosis diagnosis and more than
90% specificity for distinguishing osteoporosis from osteopenia and a normal BMD. By employing different level specific ROI thresholds, the HUs for osteoporosis obtained 140, 125, and 115 HU with 100% sensitivity in L2, L3 and L4 lumbar vertebrae, respectively. In our study, patients were grouped as the normal, osteopenic, and osteoporotic based on the DXA T-score and WHO criteria. The mean HU values in the L1–L4 vertebra levels
Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
ARTICLE IN PRESS Evaluation of BMD in the lumbar spine densitometry were determined 150, 115, and 95 in the normal, osteopenia, and osteoporotic groups, respectively. Pearson correlation coefficient between the HU values and the DXA for BMD was obtained 0.766 for BMD (p < 0.001). 6. Discussion The present study was intended to determine the density values of the lumbar bones from the routine abdominal and lumbar CT scans to provide a possibility on diagnosis of osteopenia and/or osteoporosis. According to the obtained results, it was shown that the density measurements obtained at the L1–L4 vertebra levels from the scans can help to diagnose osteopenia and/or osteoporosis. Bone mineral density measurements at L1 were found to be more accurate than other levels of the spine (24). As L1 is recognized with relative ease and is present in CT scans of the chest and abdomen, nonspecialists could potentially use this technique with minimal additional training requirement. In our study, CT-measured bone attenuation was correlated with DXA scan BMD, which is considered the gold standard for diagnosing osteoporosis. To correlate the diagnosis of osteopenia and osteoporosis based on the HU and DXA, various approaches were suggested. One approach is to group patients based on the DXA data and the mean HU measures. In a study by Schreiber et al. (25) on 25 old patients with a mean age of 71.3 years who were underwent on abdominal or lumbar CT scans and also lumbar spine DXA scans, it was found a significant correlation between the Hounsfield units and bone mineral density. The calculated mean and standard deviation values for the normal, osteopenic, and osteoporotic bone densities in the spine of the patients obtained were 133.0 ± 37.6, 100.8 ± 24.5, and 78.5 ± 32.4, respectively. Lee et al. (26) have suggested the mean and standard deviation values based on the lumbar HUs to 120.8 ± 41.8, 78.8 ± 23.0 and 54.7 ± 25.2 for normal, osteopenic, and osteoporotic bone densities in 128 female patients with the mean ages of 66.4 years, respectively. We also determined the mean HU values in the L1–L4 vertebra levels to 150, 115, and 95 in the related groups, respectively. The different results in the mentioned studies compared with our study may have been related to the differences in the studied population (e.g. race, no. of samples, age and gender) and also the equipment. Another approach is based on determination of the cutoff values to optimize sensitivity and specificity using receiver operating characteristic analysis. In a study conducted by Pickhardt et al. (27), comparing the corpus vertebrae densities of 252 patients with DXA and QCT, and selecting the threshold HU values as 160 HU for L1 vertebra, 130 HU for L3 vertebra and an average of 145 HU between T12 and L5, they found a sensitivity of 100% in the diagnosis of osteoporosis. Meanwhile, in a study conducted by Majumdar and Leslie (28) a threshold of 110 HU was proposed as a cutoff with a high specificity for identifying patients at a risk of osteoporosis. On the other hand in our study, the threshold values of 155 HU and 140 HU, respectively in the L1 and L2 lumbar spines were shown it is a sensitivity of 100% in the diagnosis of osteoporosis. Also, based on the data on the threshold value of 180 HU in the L1 level, the sensitivity of 95% was obtained in the diagnosis of osteopenia from the normal case.
5 Many of the existing CT abdominal and pelvic CT scans that might be used for the diagnosis of normal, osteopenic, and osteoporotic bone densities have been acquired after IV contrast administration. Because contrast media increase X-ray absorption, it would be expected that BMD values in perfused areas such as the trabecular compartment of the vertebrae will increase. Contrast-enhanced CT leads to underestimation of osteoporosis compared to unenhanced CT. Adjusting for contrast injection phase may improve CT screening protocols for osteoporosis (29). Therefore, both noncontrast and contrast-enhanced abdominal CT scans can be employed for opportunistic osteoporosis screening. There were studies showing that QCT gives more accurate results than DXA in the evaluation of bone mineral density (30), (31) and (32). Our study on routine abdominal and lumbar MDCT examinations showed that the percent of missed osteoporosis diagnosis was low compared to the DXA. In some study, it was suggested a lower diagnostic accuracy in trabecular vertebral density measurements on routine CT related to the bone mineral density as measured by DXA than previously reported (33). When the QCT based BMD determination is much less affected by degenerative changes of the spine than standard anteroposterior DXA, therefore, QCT may be better suited to monitor changes in trabecular BMD during menopause, and may suggest QCT as a preferred approach in differentiation of osteoporotic fractures (34), (35) and (36). On the other hand, Pickhardt et al., have emphasized that, due to similarity of ROI measures from lumbar corpus vertebrae by the QCT and DXA methods, ROI measurements could be used for rapid diagnosis of osteoporosis (27). It must be mentioned that along with QCT, magnetic resonance imaging method has also been developed in an attempt to diagnose osteoporosis in its early stages. In a study conducted by Bandirali et al. (37), on comparing lumbar spine BMD with MRI and DXA, it was found that lumbar spine MRI that was routinely performed for low back pain, may be used as an opportunistic screening tool for osteoporosis with accuracy of about 83%, but the cost-effective benefits limit popularity of such studies. This study has some limitations which have to be pointed out. Our study as a retrospective evaluation needed some larger number of subjects and also included an extended age range to an absolute conclusion. Meanwhile, for an accurate measures, an obvious or known bone abnormalities such as fractures, deformities, metastases should not be included, as well as, regularly calibration of the imaging system is necessary to avoid drifting of the CT numbers, proper selection of vertebrae, and necessity of future prospective studies, bring up a need for some more extended studies to generalize the approach for BMD. 7. Conclusion Bone mineral density values derived from the routine abdominal and lumbar spine multi-detector CT may also be used for a population osteoporosis screening with no additional costs to the patient. When MDCT densitometry is not subjected to an absolute standard, therefore, the density values obtained from different scanners with different calibration systems will significantly differ and the phantom may be used in site calibration for BMD measurements.
Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
ARTICLE IN PRESS 6 Conflict of interest The authors declare that there are no conflict of interests. Acknowledgments This research is financially supported by a research grant by the Immunology Research Center in Tabriz University of Medical Sciences (Grant 5/47/2318), Tabriz, Iran. The authors wish to have a greatly thanks from the staff and also the head of Private Medical Imaging Centre of Nova, Maragheh, Iran. References (1) Chen Li. k Measure for bone density connectivity. IEEE ISIE 2006:489–94. (2) Bauer Jan S, Link Thomas M. Advances in osteoporosis imaging. Eur J Radiol 2009;71:440–9. (3) Marshall D, Johnell O, Wedel H. Meta-analysis of how well measures of bone mineral density predict occurrence of osteoporotic fractures. BMJ 1996;312:1254–9. (4) Baron JA, Karagas M, Barrett J, Kniffin W, Malenka D, Mayor M, et al. Basic epidemiology of fractures of the upper and lower limb among Americans over 65 years of age. Epidemiology 1996;7:612–8. (5) Van der Klift M, De Laet CE, McCloskey EV, Hofman A, Pols HA. The incidence of vertebral fractures in men and women: the Rotterdam study. J Bone Miner Res 2002;17:1051–6. (6) Fogelman I, Blake GM. Different approaches to bone densitometry. J Nucl Med 2000;41, 2015–5. (7) Genant HK, Engelke K, Fuerst T, Glu¨er CC, Grampp S, Harris ST, et al. Non-invasive assessment of bone mineral and structure: state of the art. J Bone Miner Res 1996;11:707. (8) Resnick Donald. Diagnosis of bone and joint disorders. WB Saunders Fourth Ed 2002;3:1816–64. (9) Messina C, Bandirali M, Sconfienza LM, D’Alonzo NK, Di Leo G, Papini GD, et al. Prevalence and type of errors in dual-energy X-ray absorptiometry. Eur Radiol 2015;25:1504–11. (10) Genet HK. Assessing osteoporosis: CT’s quantitative advantage. Diagn Imag 1985:233–9. (11) Adams JE. Developments in QCT & comparisons with DEXA. RSNA 2000;242. (12) Engelke K, Adams JE, Armbrecht G, Augat P, Bogado CE, Bouxsein ML, et al. Clinical use of quantitative computed tomography and peripheral quantitative computed tomography in the management of osteoporosis in adults: the 2007 ISCD official positions. J Clin Densitom 2008;11:123–62. (13) Kalender WA. CT: the unexpected evolution of an imaging modality. Eur Radiol 2005;15(Suppl. 4):D21–4. (14) Wu SY, Jia HH, Hans D, Lan J, Wang LY, Li JX, et al. Assessment of volumetric bone mineral density of the femoral neck in postmenopausal women with and without vertebral fractures using quantitative multi-slice CT. J Zhejiang Univ Sci B 2009;10:499–504. (15) Wegrzyn J, Roux JP, Arlot ME, Boutroy S, Vilayphiou N, Guyen O, et al. Determinants of the mechanical behavior of human lumbar vertebrae after simulated mild fracture. J Bone Miner Res 2011;26:739–46. (16) Prevrhal S, Engelke K, Genant HK. PQCT: peripheral quantititive computed tomography. In: Grampp S, editor. Radiology of osteoporosis. Berlin, Heidelberg: Springer-Verlag; 2008. p. 143–62. (17) Raisz LG. Clinical practice. Screening for osteoporosis. N Engl J Med 2005;353:164–71. (18) Ebeling PR. Clinical practice. Osteoporosis in men. N Engl J Med 2008;358:1474–82.
J. Pirayesh Islamian et al. (19) Bessette L, Ste-Marie LG, Jean S, Davison KS, Beaulieu M, Baranci M, et al. The care gap indiagnosis and treatment of women with a fragility fracture. Osteoporos Int 2008;19: 79–86. (20) Metge CJ, Leslie WD, Manness LJ, Yogendran M, Yuen CK, Kvern B. Maximizing osteoporosis management in Manitoba steering committee. Postfracture care for older women: gaps between optimal care and actual care. Can Fam Phys 2008;54:1270–6. (21) ACR practice guideline for the performance of quantitative computed tomography (QCT) bone densitometry. Amended 2014; Resolution. vol. 39. p. 1–14. (22) Engelke K, Adams JE, Armbrecht G, Augat P, Bogado CE, Bouxsein ML, et al. Clinical use of quantitative computed tomography and peripheral quantitative computed tomography in the management of osteoporosis in adults: the 2007 ISCD official positions. J Clin Densitom 2008;11(1):123–62. (23) Steiger P, Block JE, Steiger S, et al. Spinal bone mineral density measured with quantitative CT: effect of region of interest, vertebral level, and technique. Radiology 1990;175(2):537–43. (24) Pickhardt PJ, Pooler BD, Lauder T, del Rio AM, Bruce RJ, Binkley N. Opportunistic screening for osteoporosis using abdominal computed tomography scans obtained for other indications. Ann Int Med 2013;158(8):588–95. (25) Schreiber JJ, Anderson PA, Rosas HG, Buchholz AL, Au AG. Hounsfield units for assessing bone mineral density and strength: a tool for osteoporosis management. J Bone Joint Surg Am 2011;93:1057–63. (26) Lee S, Chung CK, Oh SH, Park SB. Correlation between bone mineral density measured by dual-energy X-ray absorptiometry and Hounsfield units measured by diagnostic CT in lumbar spine. J Korean Neurosurg Soc 2013;54:384–9. (27) Pickhardt PJ, Lee LJ, el Rio AM. Simultaneous screening for osteoporosis at CT colonography: bone mineral density assessment using MDCT attenuation techniques compared with the DXA reference standard. JBMR 2011;26(9):2194–203. (28) Majumdar SR, Leslie WD. Conventional computed tomography imaging and bone mineral density: opportunistic screening or ‘‘incidentaloporosis”? Ann Int Med 2013;158:630–1. (29) Pompe Esther, Willemink Martin J, Dijkhuis Gawein R, Harald J, et al. Intravenous contrast injection significantly affects bone mineral density measured on CT. Eur Radiol 2014;12:745–53. (30) Guglielmi G, Grimston SK, Fischer KC, Pacifici R. Osteoporosis diagnosis with lateral and posteroanterior dual X-ray absorptiometry compared with quantitative C. Radiology 1994;192:845–50. (31) Pacifici R, Rupich R, Griffin M, Chines A, Susman N, Avioli LV. Dual energy radiography versus quantitative computer tomography for the diagnosis of osteoporosis. J Clin Endocrinol Metab 1990;70:705–10. (32) Rehman Q, Lang T, Modin G, Lane NE. Quantitative computed tomography of the lumbar spine, not dual X-ray absorptiometry, is an independent predictor of prevalent vertebral fractures in postmenopausal women with osteopenia receiving long-term glucocorticoid and hormonereplacement therapy. Arthritis Rheumat 2002;46:1292–7. (33) Yu W, Gluer C-C, Grampp S, Jergas M, Fuerst T, Wu CY, et al. Spinal bonemineral assessment in post menopausal women: a comparison between dual X-ray absorptiometry and quantitative computed tomography. Osteoporos Int 1995;5:433439. (34) Duboeuf F, Jergas M, Schott AM, Wu C, Gluer C, Genant H. A comparison of bone densitometry measurements of the central skeleton in post-menopausal women with and without vertebral fracture. Br J Radiol 1995;68:747–53. (35) Ross PD, Genant HK, Davis JW, Miller PD, Wasnich RD. Predicting vertebral fracture incidence from prevalent fractures and bone density among non-black, osteoporotic women. Osteoporos Int 1993;3:120–6.
Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
ARTICLE IN PRESS Evaluation of BMD in the lumbar spine densitometry (36) Buckens CF, Dijkhuis G, Keizer B, Verhaar HJ, de Jong PA. Opportunistic screening for osteoporosis on routine computed tomography? An external validation study. Eur Radiol 2015;25:2074–9.
7 (37) Bandirali M, Di Leo G, Papini GD, Messina C, Sconfienza LM, Ulivieri FM, et al. A new diagnostic score to detect osteoporosis in patients undergoing lumbar spine MRI. Eur Radiol 2015;25:2951–9.
Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
Egyptian Society of Radiology and Nuclear Medicine
The Egyptian Journal of Radiology and Nuclear Medicine www.elsevier.com/locate/ejrnm www.sciencedirect.com
ORIGINAL ARTICLE
Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry Jalil Pirayesh Islamian a, Islam Garoosi b,*, Kourosh Abdollahi Fard c, Mohammad R. Abdollahi c a
Immunology Research Center in Tabriz University of Medical Sciences, Tabriz, Iran International Branch of Tabriz University of Medical Sciences (Aras), Jolfa, Iran c Private Medical Imaging Centre of Nova, Maragheh, Iran b
Received 12 April 2015; accepted 3 April 2016 Available online xxxx
KEYWORDS Bone mineral density; Computed tomography; Dual-energy X-ray absorptiometry; Hydroxyapatite; Osteoporosis
Abstract Purpose: To determine the bone mineral density of lumbar spine vertebrae by generating computerized tomography (CT) densitometric data based on the Hounsfield units (HU) from abdominal and lumbar spine CT examinations. Material and methods: All the CT examinations were performed with a 16-slice CT system. A designed phantom of the gelatin solubilized hydroxyapatite, simulating the spine, was used for phantom studies. Sixty-one patients who underwent the abdominal CTs and also the following dual-energy X-ray absorptiometry examinations were evaluated. Results: The diagnosed cases of osteoporotic, osteopenic and normal bone densities were obtained 42.9%, 32.1%, 25% by multi-detector CT and 21.4%, 53.6%, 25% by dual-energy X-ray absorptiometry examinations for the 61 subjects, respectively. Using a trabecular ROI, a threshold of 155 HU at the L1 spine level yields a 100% sensitivity for osteoporosis and a threshold of 115 HU was shown more than 90% specificity for differentiating osteoporosis from osteopenia and also a normal bone mineral density. Conclusions: Bone mineral density values derived from the routine abdominal and lumbar spine multi-detector CT examinations may also be used for the population osteoporosis screening. Ó 2016 The Egyptian Society of Radiology and Nuclear Medicine. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
1. Introduction
* Corresponding author. Tel.: +98 9141490690. E-mail address: [email protected] (I. Garoosi). Peer review under responsibility of The Egyptian Society of Radiology and Nuclear Medicine.
Bone density is the amount of bone tissue in a certain volume of the bone (1). It is often very difficult to establish the measure with a non-invasive approach. Therefore, the term bone mineral density (BMD) is conventionally used instead, so that
http://dx.doi.org/10.1016/j.ejrnm.2016.04.005 0378-603X Ó 2016 The Egyptian Society of Radiology and Nuclear Medicine. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
ARTICLE IN PRESS 2 BMD is the most important determinant of bone fragility in evaluation of osteoporosis (2). Patients with a reduced bone mineral density have an increased risk of bone fracture (3), particularly at hip (4) and spine (5). BMD can be measured in a variety of skeletal regions and techniques (6). Dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) of the lumbar spine were considered as preferred methods for evaluation of BMD. DXA was recommended by the World Health Organization (WHO) as a gold standard for diagnosing osteoporosis. Because of its availability, related minimal radiation exposure and simplicity of use, DXA is the most commonly employed quantitative radiologic method to assess the bone mass (7). However, DXA has some pertinent disadvantages that are needed to be considered: (a) It is a two-dimensional measurement, which only measures density/area (in g/cm2). (b) The DXA of hip and spine is also sensitive to underestimate in cases such as degenerative changes that have an increased local densities (8). In a recent study on DXA pitfalls by Messina et al. (9), authors reported a high rate of errors in DXA estimations. They found that more than 90% of DXA examinations, performed in clinical practice, were affected by at least one error, and 79% of the errors were related to an inappropriate analysis during the related image processing phenomena. QCT has grown from its initial development in the 1970s to become an established technique to assess skeletal status, response to the therapy for osteoporosis and also other metabolic bone diseases. It is widely accepted that QCT is the most sensitive method available to detect osteoporosis (10,11). It is unique among the current noninvasive approaches to the bone mineral measurements as it measures true three-dimensional BMD as opposed to the area (two-dimensional) density measures obtained from some protection techniques. By QCT, it can measure the trabecular, the cortical or the integral bone, centrally or peripherally. Although this technique has some important advantages over DXA, BMD values depend on bone marrow composition so it may underestimate the bone mineral content. The radiation dose delivered by a QCT scan is significantly higher than DXA (200 lSv vs 15 lSv) (12), which limits the technique not only for population screening but also for the conventional diagnostics. Additionally, the technique has a high degree of operator dependency, limited access to the scanners, a high cost examination as compared to DXA, complexity in quality control and necessity to a well-trained operator for a scan execution (12–16). Hence the DXA is still the technique of choice. When osteoporosis is a prevalent and treatable disease and conveys a considerable fracture risk, yet it remains substantially under diagnosed and undertreated (17–20). Safe and cost-effective alternatives are needed to increase the related detection rates. Abdominal CT is one of the most frequently used diagnostic examinations. Retrieval of BMD data available on body CT examinations, ordered for other indications, requires no additional costs, no patient scanning or additional radiation exposures, and the related data can be retrospectively achieved. It could therefore expand the population screening efforts for osteoporosis. 2. Aims and objectives The objective of this study was to determine the bone mineral density of lumbar spine (L1–L4) vertebrae by generating CT
J. Pirayesh Islamian et al. densitometric data based on Hounsfield units from routine abdominal and lumbar spine MDCT examinations and comparing with those of DXA scanners and investigate whether these data can be used to suitably differentiate osteoporotic, osteopenic or normal bone density conditions. 3. Materials and methods This retrospective single-institute study, approved by the institutional review board, was conducted in accordance with the ethical standards of the Declaration of Helsinki. The designed phantom simulating the spine of a human, was filled from the gelatin solubilized of 60, 80,100, 120, 140 mg/cm3 hydroxyapatite, placed in the ‘‘spine” region in a water filled polyethylene container (Fig. 1). Also, there are no documented standards for assigning diagnostic categories based on the QCT spine BMD measurements, according to American College of Radiology (ACR) recommendations (21) and the suggestions by International Society for Clinical Densitometry (ISCD) in 2007 (22) and the following category definitions were considered for the QCT of the spine BMD measurements similar to the WHO diagnostic categories that are used to hip BMD measurements. The patient category definitions are also based on the actual volumetric BMD with a threshold of 120 mg/cm3 for osteopenia (a DXA T-score of 1.0) and 80 mg/cm3 for osteoporosis (a DXA T-score of 2.5). In 2007, ISCD has developed some official positions for the clinical use of DXA and non-DXA technologies, which point out that a single-slice spinal QCT should include the vertebral bodies of L1–L3, and also a 3D QCT should include L1–L2 (22). In addition, T12 or L3–L4 are usually suggested as the alternative vertebral bodies in cases that the included one is not eligible for the measurement (23). The BMD of the designed phantom was included for the related densities of normal, osteopenia and osteoporosis. For phantom study, after daily routine calibration of the CT scanner as per manufacturer’s recommendations, the designed phantom was scanned with a 16-slice CT system (Toshiba Alexion Advance Edition 16, Japan). Also, sixty-one patients (38 females and 23 males with a mean age of 60.2 years) who underwent a trunk CT and also the following DXA examination, due to a suspected osteoporosis from a weak damaged trauma and bone densitometry were evaluated. Patients with a history of CT scanning for a non-contrast abdominal or a weak damaged trauma on the lumbar spine and the followed DXA for bone densitometry in an interval of two months after CT scanning were also included in our study. The patients under 50-years old and also those with an apparent bone fracture were excluded. A routine abdominal MDCT protocol was used for the both phantom and patient study. The CT parameters were included: a tube voltage of 120 kVp, a tube current of 160 mA s, the beam collimation size of 16 1 mm, a pitch factor of 0.938 mm, an imaging slice of 5 mm, and a bone reconstruction algorithm with a window width 1500, in a window level of 300. The related two dimensional reconstructions were obtained in a sagittal plane. A 20 10 mm ROI of elliptical shape ROI was located in middle trabecular of the vertebral body for the phantom less condition (Fig. 2). All the DXA measures were done with a Hologic Explorer densitometer (USA). Information from DXA scans, including
Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
ARTICLE IN PRESS Evaluation of BMD in the lumbar spine densitometry
3
Fig. 1 Scanning position of a homemade lumbar vertebrae phantom (A) in a water filed polyethylene container, as torso region of a human. (B) The hydroxyapatite concentrations were set to 60, 80, 100, 120, and 140 (mg/cm3) for vertebrae phantom 1, 2, 3, 4 and 5, respectively.
T-scores and bone mineral densities (in g/cm2), was obtained from L1 to L4 lumbar vertebrae.
were calculated according to the L1–L4 HUs. All statistical tests were two sided and performed at a significant level of p < 0.05.
4. Statistical analysis
5. Results
The Statistical Analysis was carried out using Statistical Package for Social Sciences (SPSS) software, Version 21.0. The correlation parameters between DXA and abdominal and lumbar MDCTs
The designed phantom allowed to calibrate a MDCT system as a technique in determination of spinal BMD. The data on mean HU of the phantom for MDCT were obtained 75, 101,
Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
ARTICLE IN PRESS 4
J. Pirayesh Islamian et al.
Fig. 2 Computed tomography scans illustrating calculation of the vertebral BMD based on Hounsfield units (a 56 year female). Corresponding lateral (A) and anteroposterior (B) scout images of the abdominal. (C) Axial cross-sectional images showing HU values generated with an oval ROI.
127, 153 and 177 HU, respectively for the related lumbar phantom densities 60, 80, 100, 120 and 140 (mg/cm3). The diagnosed cases of osteoporotic, osteopenic and normal bone densities from the 61 subjects undergone the MDCT were scored 42.9%, 32.1%, and 25%, respectively, and by the DXA screening approach the related diagnosis was obtained 21.4%, 53.6%, and 25%, respectively. A trabecular ROI with an attenuation threshold of 155 HU at the L1 level yields a 100% sensitivity for osteoporosis diagnosis and more than
90% specificity for distinguishing osteoporosis from osteopenia and a normal BMD. By employing different level specific ROI thresholds, the HUs for osteoporosis obtained 140, 125, and 115 HU with 100% sensitivity in L2, L3 and L4 lumbar vertebrae, respectively. In our study, patients were grouped as the normal, osteopenic, and osteoporotic based on the DXA T-score and WHO criteria. The mean HU values in the L1–L4 vertebra levels
Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
ARTICLE IN PRESS Evaluation of BMD in the lumbar spine densitometry were determined 150, 115, and 95 in the normal, osteopenia, and osteoporotic groups, respectively. Pearson correlation coefficient between the HU values and the DXA for BMD was obtained 0.766 for BMD (p < 0.001). 6. Discussion The present study was intended to determine the density values of the lumbar bones from the routine abdominal and lumbar CT scans to provide a possibility on diagnosis of osteopenia and/or osteoporosis. According to the obtained results, it was shown that the density measurements obtained at the L1–L4 vertebra levels from the scans can help to diagnose osteopenia and/or osteoporosis. Bone mineral density measurements at L1 were found to be more accurate than other levels of the spine (24). As L1 is recognized with relative ease and is present in CT scans of the chest and abdomen, nonspecialists could potentially use this technique with minimal additional training requirement. In our study, CT-measured bone attenuation was correlated with DXA scan BMD, which is considered the gold standard for diagnosing osteoporosis. To correlate the diagnosis of osteopenia and osteoporosis based on the HU and DXA, various approaches were suggested. One approach is to group patients based on the DXA data and the mean HU measures. In a study by Schreiber et al. (25) on 25 old patients with a mean age of 71.3 years who were underwent on abdominal or lumbar CT scans and also lumbar spine DXA scans, it was found a significant correlation between the Hounsfield units and bone mineral density. The calculated mean and standard deviation values for the normal, osteopenic, and osteoporotic bone densities in the spine of the patients obtained were 133.0 ± 37.6, 100.8 ± 24.5, and 78.5 ± 32.4, respectively. Lee et al. (26) have suggested the mean and standard deviation values based on the lumbar HUs to 120.8 ± 41.8, 78.8 ± 23.0 and 54.7 ± 25.2 for normal, osteopenic, and osteoporotic bone densities in 128 female patients with the mean ages of 66.4 years, respectively. We also determined the mean HU values in the L1–L4 vertebra levels to 150, 115, and 95 in the related groups, respectively. The different results in the mentioned studies compared with our study may have been related to the differences in the studied population (e.g. race, no. of samples, age and gender) and also the equipment. Another approach is based on determination of the cutoff values to optimize sensitivity and specificity using receiver operating characteristic analysis. In a study conducted by Pickhardt et al. (27), comparing the corpus vertebrae densities of 252 patients with DXA and QCT, and selecting the threshold HU values as 160 HU for L1 vertebra, 130 HU for L3 vertebra and an average of 145 HU between T12 and L5, they found a sensitivity of 100% in the diagnosis of osteoporosis. Meanwhile, in a study conducted by Majumdar and Leslie (28) a threshold of 110 HU was proposed as a cutoff with a high specificity for identifying patients at a risk of osteoporosis. On the other hand in our study, the threshold values of 155 HU and 140 HU, respectively in the L1 and L2 lumbar spines were shown it is a sensitivity of 100% in the diagnosis of osteoporosis. Also, based on the data on the threshold value of 180 HU in the L1 level, the sensitivity of 95% was obtained in the diagnosis of osteopenia from the normal case.
5 Many of the existing CT abdominal and pelvic CT scans that might be used for the diagnosis of normal, osteopenic, and osteoporotic bone densities have been acquired after IV contrast administration. Because contrast media increase X-ray absorption, it would be expected that BMD values in perfused areas such as the trabecular compartment of the vertebrae will increase. Contrast-enhanced CT leads to underestimation of osteoporosis compared to unenhanced CT. Adjusting for contrast injection phase may improve CT screening protocols for osteoporosis (29). Therefore, both noncontrast and contrast-enhanced abdominal CT scans can be employed for opportunistic osteoporosis screening. There were studies showing that QCT gives more accurate results than DXA in the evaluation of bone mineral density (30), (31) and (32). Our study on routine abdominal and lumbar MDCT examinations showed that the percent of missed osteoporosis diagnosis was low compared to the DXA. In some study, it was suggested a lower diagnostic accuracy in trabecular vertebral density measurements on routine CT related to the bone mineral density as measured by DXA than previously reported (33). When the QCT based BMD determination is much less affected by degenerative changes of the spine than standard anteroposterior DXA, therefore, QCT may be better suited to monitor changes in trabecular BMD during menopause, and may suggest QCT as a preferred approach in differentiation of osteoporotic fractures (34), (35) and (36). On the other hand, Pickhardt et al., have emphasized that, due to similarity of ROI measures from lumbar corpus vertebrae by the QCT and DXA methods, ROI measurements could be used for rapid diagnosis of osteoporosis (27). It must be mentioned that along with QCT, magnetic resonance imaging method has also been developed in an attempt to diagnose osteoporosis in its early stages. In a study conducted by Bandirali et al. (37), on comparing lumbar spine BMD with MRI and DXA, it was found that lumbar spine MRI that was routinely performed for low back pain, may be used as an opportunistic screening tool for osteoporosis with accuracy of about 83%, but the cost-effective benefits limit popularity of such studies. This study has some limitations which have to be pointed out. Our study as a retrospective evaluation needed some larger number of subjects and also included an extended age range to an absolute conclusion. Meanwhile, for an accurate measures, an obvious or known bone abnormalities such as fractures, deformities, metastases should not be included, as well as, regularly calibration of the imaging system is necessary to avoid drifting of the CT numbers, proper selection of vertebrae, and necessity of future prospective studies, bring up a need for some more extended studies to generalize the approach for BMD. 7. Conclusion Bone mineral density values derived from the routine abdominal and lumbar spine multi-detector CT may also be used for a population osteoporosis screening with no additional costs to the patient. When MDCT densitometry is not subjected to an absolute standard, therefore, the density values obtained from different scanners with different calibration systems will significantly differ and the phantom may be used in site calibration for BMD measurements.
Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
ARTICLE IN PRESS 6 Conflict of interest The authors declare that there are no conflict of interests. Acknowledgments This research is financially supported by a research grant by the Immunology Research Center in Tabriz University of Medical Sciences (Grant 5/47/2318), Tabriz, Iran. The authors wish to have a greatly thanks from the staff and also the head of Private Medical Imaging Centre of Nova, Maragheh, Iran. References (1) Chen Li. k Measure for bone density connectivity. IEEE ISIE 2006:489–94. (2) Bauer Jan S, Link Thomas M. Advances in osteoporosis imaging. Eur J Radiol 2009;71:440–9. (3) Marshall D, Johnell O, Wedel H. Meta-analysis of how well measures of bone mineral density predict occurrence of osteoporotic fractures. BMJ 1996;312:1254–9. (4) Baron JA, Karagas M, Barrett J, Kniffin W, Malenka D, Mayor M, et al. Basic epidemiology of fractures of the upper and lower limb among Americans over 65 years of age. Epidemiology 1996;7:612–8. (5) Van der Klift M, De Laet CE, McCloskey EV, Hofman A, Pols HA. The incidence of vertebral fractures in men and women: the Rotterdam study. J Bone Miner Res 2002;17:1051–6. (6) Fogelman I, Blake GM. Different approaches to bone densitometry. J Nucl Med 2000;41, 2015–5. (7) Genant HK, Engelke K, Fuerst T, Glu¨er CC, Grampp S, Harris ST, et al. Non-invasive assessment of bone mineral and structure: state of the art. J Bone Miner Res 1996;11:707. (8) Resnick Donald. Diagnosis of bone and joint disorders. WB Saunders Fourth Ed 2002;3:1816–64. (9) Messina C, Bandirali M, Sconfienza LM, D’Alonzo NK, Di Leo G, Papini GD, et al. Prevalence and type of errors in dual-energy X-ray absorptiometry. Eur Radiol 2015;25:1504–11. (10) Genet HK. Assessing osteoporosis: CT’s quantitative advantage. Diagn Imag 1985:233–9. (11) Adams JE. Developments in QCT & comparisons with DEXA. RSNA 2000;242. (12) Engelke K, Adams JE, Armbrecht G, Augat P, Bogado CE, Bouxsein ML, et al. Clinical use of quantitative computed tomography and peripheral quantitative computed tomography in the management of osteoporosis in adults: the 2007 ISCD official positions. J Clin Densitom 2008;11:123–62. (13) Kalender WA. CT: the unexpected evolution of an imaging modality. Eur Radiol 2005;15(Suppl. 4):D21–4. (14) Wu SY, Jia HH, Hans D, Lan J, Wang LY, Li JX, et al. Assessment of volumetric bone mineral density of the femoral neck in postmenopausal women with and without vertebral fractures using quantitative multi-slice CT. J Zhejiang Univ Sci B 2009;10:499–504. (15) Wegrzyn J, Roux JP, Arlot ME, Boutroy S, Vilayphiou N, Guyen O, et al. Determinants of the mechanical behavior of human lumbar vertebrae after simulated mild fracture. J Bone Miner Res 2011;26:739–46. (16) Prevrhal S, Engelke K, Genant HK. PQCT: peripheral quantititive computed tomography. In: Grampp S, editor. Radiology of osteoporosis. Berlin, Heidelberg: Springer-Verlag; 2008. p. 143–62. (17) Raisz LG. Clinical practice. Screening for osteoporosis. N Engl J Med 2005;353:164–71. (18) Ebeling PR. Clinical practice. Osteoporosis in men. N Engl J Med 2008;358:1474–82.
J. Pirayesh Islamian et al. (19) Bessette L, Ste-Marie LG, Jean S, Davison KS, Beaulieu M, Baranci M, et al. The care gap indiagnosis and treatment of women with a fragility fracture. Osteoporos Int 2008;19: 79–86. (20) Metge CJ, Leslie WD, Manness LJ, Yogendran M, Yuen CK, Kvern B. Maximizing osteoporosis management in Manitoba steering committee. Postfracture care for older women: gaps between optimal care and actual care. Can Fam Phys 2008;54:1270–6. (21) ACR practice guideline for the performance of quantitative computed tomography (QCT) bone densitometry. Amended 2014; Resolution. vol. 39. p. 1–14. (22) Engelke K, Adams JE, Armbrecht G, Augat P, Bogado CE, Bouxsein ML, et al. Clinical use of quantitative computed tomography and peripheral quantitative computed tomography in the management of osteoporosis in adults: the 2007 ISCD official positions. J Clin Densitom 2008;11(1):123–62. (23) Steiger P, Block JE, Steiger S, et al. Spinal bone mineral density measured with quantitative CT: effect of region of interest, vertebral level, and technique. Radiology 1990;175(2):537–43. (24) Pickhardt PJ, Pooler BD, Lauder T, del Rio AM, Bruce RJ, Binkley N. Opportunistic screening for osteoporosis using abdominal computed tomography scans obtained for other indications. Ann Int Med 2013;158(8):588–95. (25) Schreiber JJ, Anderson PA, Rosas HG, Buchholz AL, Au AG. Hounsfield units for assessing bone mineral density and strength: a tool for osteoporosis management. J Bone Joint Surg Am 2011;93:1057–63. (26) Lee S, Chung CK, Oh SH, Park SB. Correlation between bone mineral density measured by dual-energy X-ray absorptiometry and Hounsfield units measured by diagnostic CT in lumbar spine. J Korean Neurosurg Soc 2013;54:384–9. (27) Pickhardt PJ, Lee LJ, el Rio AM. Simultaneous screening for osteoporosis at CT colonography: bone mineral density assessment using MDCT attenuation techniques compared with the DXA reference standard. JBMR 2011;26(9):2194–203. (28) Majumdar SR, Leslie WD. Conventional computed tomography imaging and bone mineral density: opportunistic screening or ‘‘incidentaloporosis”? Ann Int Med 2013;158:630–1. (29) Pompe Esther, Willemink Martin J, Dijkhuis Gawein R, Harald J, et al. Intravenous contrast injection significantly affects bone mineral density measured on CT. Eur Radiol 2014;12:745–53. (30) Guglielmi G, Grimston SK, Fischer KC, Pacifici R. Osteoporosis diagnosis with lateral and posteroanterior dual X-ray absorptiometry compared with quantitative C. Radiology 1994;192:845–50. (31) Pacifici R, Rupich R, Griffin M, Chines A, Susman N, Avioli LV. Dual energy radiography versus quantitative computer tomography for the diagnosis of osteoporosis. J Clin Endocrinol Metab 1990;70:705–10. (32) Rehman Q, Lang T, Modin G, Lane NE. Quantitative computed tomography of the lumbar spine, not dual X-ray absorptiometry, is an independent predictor of prevalent vertebral fractures in postmenopausal women with osteopenia receiving long-term glucocorticoid and hormonereplacement therapy. Arthritis Rheumat 2002;46:1292–7. (33) Yu W, Gluer C-C, Grampp S, Jergas M, Fuerst T, Wu CY, et al. Spinal bonemineral assessment in post menopausal women: a comparison between dual X-ray absorptiometry and quantitative computed tomography. Osteoporos Int 1995;5:433439. (34) Duboeuf F, Jergas M, Schott AM, Wu C, Gluer C, Genant H. A comparison of bone densitometry measurements of the central skeleton in post-menopausal women with and without vertebral fracture. Br J Radiol 1995;68:747–53. (35) Ross PD, Genant HK, Davis JW, Miller PD, Wasnich RD. Predicting vertebral fracture incidence from prevalent fractures and bone density among non-black, osteoporotic women. Osteoporos Int 1993;3:120–6.
Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005
ARTICLE IN PRESS Evaluation of BMD in the lumbar spine densitometry (36) Buckens CF, Dijkhuis G, Keizer B, Verhaar HJ, de Jong PA. Opportunistic screening for osteoporosis on routine computed tomography? An external validation study. Eur Radiol 2015;25:2074–9.
7 (37) Bandirali M, Di Leo G, Papini GD, Messina C, Sconfienza LM, Ulivieri FM, et al. A new diagnostic score to detect osteoporosis in patients undergoing lumbar spine MRI. Eur Radiol 2015;25:2951–9.
Please cite this article in press as: Pirayesh Islamian J et al., Comparison between the MDCT and the DXA scanners in the evaluation of BMD in the lumbar spine densitometry, Egypt J Radiol Nucl Med (2016), http://dx.doi.org/10.1016/j.ejrnm.2016.04.005