Vertebral Morphometry by DXA: A Comparison of Supine Lateral and Decubitus Lateral Densitometers (original) (raw)
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Vertebral morphometry: current methods and recent advances
European Radiology, 2008
Vertebral fractures are the hallmark of osteoporosis and are associated with increased morbility and mortality. Because a majority of vertebral fractures often occur in absence of specific trauma and are asymptomatic, their identification is radiographic. The two most widely used methods to determine the severity of vertebral fractures are the visual semiquantitative (SQ) assessment and the morphometric quantitative approach, involving the measurements of vertebral body heights. The measurements may be made on conventional spinal radiographs (MRX: morphometric X-ray radiography) or on images obtained from dual X-ray absorptiometry (DXA) scans (MXA: morphometric X-ray absorptiometry). The availability of a rapid, low-dose method for assessment of vertebral fractures, using advanced fan-beam DXA devices, provides a practical method for integrated assessment of BMD and vertebral fracture status. The visual or morphometric assessment of lateral DXA spine images may have a potential role for use as a prescreening tool, excluding normal subjects prior to performing conventional radiographs.
Skeletal Radiology, 2012
Objective The aim of this study was to investigate software accuracy and influence of body mass index on image quality of Lunar iDXA (Lunar, Madison, WI, USA; software enCORE 12.0) in vertebral fracture (VFs) assessment. Materials and methods We enrolled 65 normal or overweight patients (group 1) and 64 obese patients (group 2) with indication for morphometric evaluation of the spine. Patients underwent iDXA, with scans performed in the standard manner by an expert technologist. Lateral images of the spine were subsequently evaluated by a musculoskeletal radiologist as the gold standard. Our analysis considered five points: vertebral bodies missed or not assessable or wrongly labeled on T4-L4 segment, diagnostic performance of the automatic morphometric point-positioning system in the detection of VFs, upgrading and downgrading of fractures, radiologist intervention rate, and BMI influence. Results In group 1, 57/845 (6.7%) vertebral bodies and 34/832 (4.1%) in group 2 were not assessable-the upper thoracic spine. enCORE failed to recognize vertebral levels in 5.4% of the patients (7.7% in group 1 vs. 3.1% in group 2). On a lesionbased analysis sensitivity, specificity and accuracy of the software were 81.4, 93.8, and 93.1% in group 1 and 69.1, 88.3, and 86.7% in group 2, respectively. For 52.7% of the vertebrae in group 1 (51/8 upgraded/downgraded) and 70.0% in group 2 (96/26 upgraded/downgraded), a point correction was necessary and this changed the diagnosis respectively in 29.2 and 50.0% of the patients. Differences in diagnostic performance and point correction rate were significantly different between the two groups; however, BMI did not significantly affect vertebral level labeling and was correlated with a better visualization of the whole T4-L4 spine segment. Conclusions This study provides new and interesting information about the accuracy, reliability, and imaging quality provided by iDXA in the assessment of VFs.
Méthodes radiographiques d’évaluation des fractures vertébrales ostéoporotiques
Revue du Rhumatisme, 2009
Reproducible methods for the radiological assessment of osteoporotic vertebral fractures, defined based on accurate criteria, are needed in everyday practice and in therapeutic trials and epidemiological studies. Objectives: To describe and to evaluate methods for osteoporotic vertebral fracture assessment based on standard radiographs or dual-energy X-ray absorptiometry (DXA) and to determine the role for each method in clinical practice, therapeutic trials, and epidemiological studies. Methods: A review written by a rheumatologist based on his clinical experience and on a literature review was submitted to four experts. Studies in English or French published between 1975 and February 2008 were retrieved from Medline using the keywords vertebral fracture, osteoporosis, vertebral deformity, and vertebral fracture assessment. Results: One hundred forty-nine articles were selected and read in their full-text version. There was no consensus regarding the definition of osteoporotic vertebral fractures. The following methods were evaluated: visual assessment, Genant's semi-quantitative assessment, Jiang's algorithm-based qualitative method, morphometric radiography, and DXA of the spine. In everyday practice, Genant's semi-quantitative assessment on standard radiographs may provide useful information on the severity and prognosis of osteoporosis. DXA done for bone mineral density measurement may detect vertebral fractures in asymptomatic patients. Assessment of standard radiographs remains the reference standard for diagnosing vertebral fractures in patients with suggestive symptoms (e.g., pain in the thoracic or lumbar spine, height loss, or thoracic kyphosis). For therapeutic trials and epidemiological studies, Genant's semi-quantitative assessment used by a trained and experienced observer is the preferred method, based on its good reproducibility and ability to differentiate fractures from other deformities. However, thousands of radiographs may be needed, making routine interpretation by an expert impractical. A visual semi-quantitative method may be used to separate normal radiographs from radiographs showing possible or obvious fractures, which can then be read by an expert. Alternatively, radiomorphometric indices can be determined on digitized radiographs in combination with a semi-quantitative assessment, with discordant cases being reviewed by an expert. We do not recommend Jiang's method at present, as it is still undergoing validation.
Radiographic methods for evaluating osteoporotic vertebral fractures
Joint Bone Spine, 2009
Reproducible methods for the radiological assessment of osteoporotic vertebral fractures, defined based on accurate criteria, are needed in everyday practice and in therapeutic trials and epidemiological studies. Objectives: To describe and to evaluate methods for osteoporotic vertebral fracture assessment based on standard radiographs or dual-energy X-ray absorptiometry (DXA) and to determine the role for each method in clinical practice, therapeutic trials, and epidemiological studies. Methods: A review written by a rheumatologist based on his clinical experience and on a literature review was submitted to four experts. Studies in English or French published between 1975 and February 2008 were retrieved from Medline using the keywords vertebral fracture, osteoporosis, vertebral deformity, and vertebral fracture assessment. Results: One hundred forty-nine articles were selected and read in their full-text version. There was no consensus regarding the definition of osteoporotic vertebral fractures. The following methods were evaluated: visual assessment, Genant's semi-quantitative assessment, Jiang's algorithm-based qualitative method, morphometric radiography, and DXA of the spine. In everyday practice, Genant's semi-quantitative assessment on standard radiographs may provide useful information on the severity and prognosis of osteoporosis. DXA done for bone mineral density measurement may detect vertebral fractures in asymptomatic patients. Assessment of standard radiographs remains the reference standard for diagnosing vertebral fractures in patients with suggestive symptoms (e.g., pain in the thoracic or lumbar spine, height loss, or thoracic kyphosis). For therapeutic trials and epidemiological studies, Genant's semi-quantitative assessment used by a trained and experienced observer is the preferred method, based on its good reproducibility and ability to differentiate fractures from other deformities. However, thousands of radiographs may be needed, making routine interpretation by an expert impractical. A visual semi-quantitative method may be used to separate normal radiographs from radiographs showing possible or obvious fractures, which can then be read by an expert. Alternatively, radiomorphometric indices can be determined on digitized radiographs in combination with a semi-quantitative assessment, with discordant cases being reviewed by an expert. We do not recommend Jiang's method at present, as it is still undergoing validation.
Clinical evaluation of spine morphometric X-ray absorptiometry
Rheumatology, 1998
A new method for vertebral height measurements, morphometric X-ray absorptiometry (MXA) based on dual-energy X-ray absorptiometry, has been proposed. This technique overcomes some limitations of morphometric radiography (MRX ): the effective radiation dose is low, some sources of geometric distortion are eliminated, such as dependence on patient position, magnification gradient, and the effect of scoliosis is minimized. The purpose of this study was to compare morphometric parameters obtained by both methods (MXA and MRX ), and to evaluate the agreement between morphometric evaluations and qualitative reading for vertebral fracture diagnosis. The evaluation was performed with an Hologic QDR 2000 device in 67 women without vertebral fractures and 31 women with vertebral fractures (according to a qualitative assessment). The reproducibility of the image analysis was <4% and comparable to MRX. The estimated bias between the two methods was on average 10 mm, and was a function of the vertebral height, according to the Bland and Altman method. The agreement between MXA and other methods for vertebral fracture diagnosis was poor for the thoracic level above T7, due to a lack of resolution and rib interposition. Agreement was also low for T10, due to the motion of the diaphragm muscle. MXA cannot currently be used for the diagnosis of thoracic vertebral fracture in clinical practice. Technological improvements are necessary to make this promising method useful as a screening tool to evaluate the presence of thoracic vertebral fractures.
Osteoporosis International, 1999
Morphometric X-ray absorptiometry (MXA) offers some potential advantages over spinal radiography for the quantitative evaluation of vertebral fractures in individuals with spinal osteoporosis. This ex vivo study examined the accuracy of MXA and quantitative morphometry (QM) for the evaluation of vertebral height, in relation to direct measurements from cadaveric vertebral columns. Spinal radiographs and MXA scans were obtained from nine cadaveric vertebral columns (mean age at death 64 years). Anterior, middle and posterior vertebral body heights of all segments from T4 to L4 were measured interactively using MXA software and QM (from the spinal radiographs), and compared with direct measurements derived using digital callipers following cadaveric dissection. Coefficients of variation for repeat QM and MXA scan analysis were less than 2%. The QM and MXA measurements were both strongly correlated (r 2 = 0.99) with the direct measurements, with accuracy errors of between 2.6% and 4.3%, and 4.5% and 4.8%, for QM and MXA respectively. At the three measurement sites, analysis of measurement differences showed that QM tended to overestimate the true height and MXA tended towards under-estimation. The mean difference between the direct measurements and QM measurements ranged from 2.7% to 8.7%, and the mean difference between direct and MXA measurements ranged from -2.9% to 4.1%. There was strong linear association between the MXA and QM measure-ments (r 2 = 0.99) with mean differences at the three measurement sites ranging from -4.1% to -5.9%. Under the optimal (ex vivo) scanning conditions used in this study, MXA is comparable to spinal radiography for the assessment of vertebral height. Further studies are required to determine the conditions under which satisfactory MXA image resolution and measurement accuracy can be achieved in a clinical population.
Measurement of vertebral area on spine X-rays in osteoporosis: Reliability of digitizing techniques
Journal of Bone and Mineral Research, 2009
Much of the clinical research in osteoporosis is directed toward documenting a reduction in vertebral fracture rate, but there is considerable disagreement about defining and quantifying vertebral fractures. We have evaluated the technique of digitizing landmarks identified on lateral radiographs of thoracic and lumbar vertebrae and computing vertebral body area. Reduction in area indicates that fractures occurred. Radiographs from 10 patients with osteoporosis and vertebral fractures were obtained from each of two centers, Henry Ford Hospital (HFH) and Mayo Clinic (MC), and vertebral area for each individual in the complete set of 20 radiographs was calculated at each center. Measurements at the two centers differed by a multiplicative constant related to the method of recording landmarks on the radiographs that was estimated using 300 x-rays from HFH. After adjusting the MC areas for this multiplicative relationship, the average ratio of the HFH areas to the transformed MC areas of individual vertebrae (T4-L5) ranged from 0.98 to 1.06. The correlation between HFH and transformed MC areas for individual vertebrae averaged 0.85, with slopes between 0.87 and 1.00, intercept average-0.57. Within-patient rank correlation averaged 0.97. We conclude that radiographic digitization is a reliable and reproducible method of determining vertebral body dimensions that is suitable for evaluating radiographs obtained at different clinical sites and for comparison with normal data. This technique should prove useful for documenting the presence of a vertebral fracture that may not be readily apparent on visual inspection of radiographs and for monitoring serial changes in vertebral body dimensions in long-term epidemiologic and therapeutic studies.