2015 ISCD Position Development ConferenceClinical Use of Quantitative Computed Tomography–Based Advanced Techniques in the Management of Osteoporosis in Adults: the 2015 ISCD Official Positions—Part III
Introduction
This is part III of the report of the quantitative computed tomography (QCT) task force addressing the evolving clinical use of QCT and providing evidence on new and updated official International Society for Clinical Densitometry (ISCD) position statements.
CT is the most widely used 3-dimensional (3D) diagnostic imaging modality in clinical practice. The additional use of pre-existing abdominal or pelvic CT images to quantify bone mineral density (BMD) may be cost-effective and reduce radiation exposure. There is also an increasing interest in the retrospective use of existing CT examinations for opportunistic screening and identification of those with prevalent vertebral fracture (1). One difficulty is the absence of an in-scan calibration phantom. Techniques using retrospective BMD calibration with a phantom or internal calibration will be reviewed.
This part reviews current techniques and introduces new official ISCD positions for the use of asynchronous calibration and opportunistic screening. Part I covers the clinical value of QCT of the hip and part II the clinical value of bone strength calculated by QCT-based finite element analysis.
Part III also reviews the evidence for the clinical use of a new category of QCT-based methods denoted statistical parameter mapping. They describe the distribution of so-called features, which may be BMD, cortical thickness, or stress within the bone. Although the number of studies applying statistical parametric mapping (SPM) is still small and evidence is limited, the clinical potential of these emerging methods deserves attention.
Section snippets
Assessing BMD From CT Scans Without an In-Scan Calibration Phantom—Feasibility of Opportunistic Screening
Osteoporosis is still largely underdiagnosed and many subjects at high fracture risk are not treated despite a large variety of available interventions (2). Thus, there is increasing interest in using pre-existing CT scans of the abdomen and/or pelvis for the assessment of BMD to screen for those at increased fracture risk. This is a promising approach, which is convenient for the patient as images already exist. In this case, a dual-energy X-ray absorptiometry (DXA) scan may be avoided, which
Statistical Parametric Mapping
With the exception of finite element modeling, analytic approaches to derive density, morphometry, and strength measurements are based on predefined volumes of bone tissue computed from the coordinates of bony landmarks. Although such approaches may identify anatomically distinct or biomechanically loaded bone regions, they are at odds with the concept that bone structure represents a 3D whole-organ adaptation to perturbations in mechanical loading, hormonal milieu, and blood flow, among other
Methodology
A systematic literature search in MEDLINE for opportunistic screening using the clause: (QCT[All Fields] OR CT[All Fields] OR (quantitative[All Fields] AND (computed[All Fields] OR computerized[All Fields]) AND tomograph*[All Fields]) AND (“opportuni*”[All fields] OR “phantom less”[All Fields] OR “internal calibration”[All Fields] OR calibration*[title])) identified 162 entries.
We restricted our evaluation to human studies; animal studies were not included in the systematic review. We also did
ISCD Official Position
For density-based QCT measurements, the in-scan calibration phantom can be replaced by asynchronous calibration if scanner stability is maintained.
Additional Questions for Future Research
The dual use of CT scans (for example, of the abdomen or the pelvis) is highly promising and may help identify patients with a high fracture risk. However, the use of routine clinical CT scans for this purpose largely depends on the stability of the CT scanner. Obviously, scanner stability is less important if the main purpose is diagnostic screening followed by an additional DXA scan as here the differentiation into high and low risk is the main aim. For a more accurate assessment of fracture
Acknowledgments
We acknowledge the input of A. Brett from Mindways Inc. who served as external expert.
References (37)
Conversion relations for quantitative CT bone mineral density measured with solid and liquid calibration standards
Bone Miner
(1992)- et al.
Phantom-less QCT BMD system as screening tool for osteoporosis without additional radiation
Eur J Radiol
(2011) - et al.
Reanalysis precision of 3D quantitative computed tomography (QCT) of the spine
Bone
(2009) - et al.
BMD measurements of the spine derived from sagittal reformations of contrast-enhanced MDCT without dedicated software
Eur J Radiol
(2011) - et al.
New approaches in brain morphometry
Am J Geriatr Psychiatry
(2002) - et al.
Identify fracture-critical regions inside the proximal femur using statistical parametric mapping
Bone
(2009) - et al.
Bone fracture risk estimation based on image similarity
Bone
(2009) - et al.
Structural patterns of the proximal femur in relation to age and hip fracture risk in women
Bone
(2013) - et al.
Voxel-based modeling and quantification of the proximal femur using inter-subject registration of quantitative CT images
Bone
(2007) - et al.
High resolution cortical bone thickness measurement from clinical CT data
Med Image Anal
(2010)
Conventional computed tomography imaging and bone mineral density: opportunistic screening or “incidentaloporosis”?
Ann Intern Med
Clinician's guide to prevention and treatment of osteoporosis
Osteoporos Int
The use of clinical CT for baseline bone density assessment
J Comput Assist Tomogr
Can abdominal multi-detector CT diagnose spinal osteoporosis?
Eur Radiol
Converted lumbar BMD values derived from sagittal reformations of contrast-enhanced MDCT predict incidental osteoporotic vertebral fractures
Calcif Tissue Int
Bone mineral density measurements of the proximal femur from routine contrast-enhanced MDCT data sets correlate with dual-energy X-ray absorptiometry
Eur Radiol
Comparison of femoral neck BMD evaluation obtained using lunar DXA and QCT with asynchronous calibration from CT colonography
J Clin Densitom
Feasibility of simultaneous computed tomographic colonography and fully automated bone mineral densitometry in a single examination
J Comput Assist Tomogr
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