title: Assessment of Bone Fragility in Patients With Multiple Myeloma Using QCT-Based Finite Element Modeling.
abstract: Multiple myeloma (MM) is a malignant plasma cell disease associated with severe bone destruction. Surgical intervention is often required to prevent vertebral body collapse and resulting neurological complications; however, its necessity is determined by measuring lesion size or number, without considering bone biomechanics. Finite element (FE) modeling, which simulates the physiological loading, may improve the prediction of fragility. To test this, we developed a quantitative computed tomography (QCT)-based FE model of the vertebra and applied it to a dataset of MM patients with and without prevalent fracture. FE models were generated from vertebral QCT scans of the T12(T11if T12was fractured) of 104 MM patients, 45 with fracture and 59 without, using a low-dose scan protocol (1.5 mm slice thickness, 4.0 to 6.5 mSv effective dose). A calibration phantom enabled the conversion of the CT Hounsfield units to FE material properties. Compressive loading of the vertebral body was simulated and the stiffness, yield load, and work to yield determined. To compare the parameters between fracture and nonfracture groups, t tests were used, and standardized odds ratios (sOR, normalized to standard deviation) and 95% confidence intervals were calculated. FE parameters were compared to mineral and structural parameters using linear regression. Patients with fracture showed lower vertebral stiffness (-15.2%; p = 0.010; sOR = 1.73; 95% CI, 1.11 to 2.70), yield force (-21.5%; p = 0.002; sOR = 2.09; 95% CI, 1.27 to 3.43), and work to yield (-27.4%; p = 0.001; sOR = 2.28; 95% CI, 1.33 to 3.92) compared to nonfracture patients. All parameters correlated significantly with vBMD (stiffness: R2= 0.57, yield force: R2= 0.59, work to yield: R2= 0.50, p < 0.001), BV/TV (stiffness: R2= 0.56, yield force: R2= 0.58, work to yield: R2= 0.49, p < 0.001), and Tb.Sp (stiffness: R2= 0.51, yield force: R2= 0.53, work to yield: R2= 0.45, p < 0.001). FE modeling identified MM patients with compromised mechanical integrity of the vertebra. Higher sOR values were obtained for the biomechanical compared to structural or mineral measures, suggesting that FE modeling improves fragility assessment in these patients. © 2016 American Society for Bone and Mineral Research.
authors.affiliation: Section Biomedical Imaging, Department of Radiology and Neurology, University Hospital Schleswig-Holstein, Kiel, Germany.|Institute of Biomechanics, Hamburg University of Technology, Hamburg, Germany.
authors.forename: Graeme M
authors.initials: GM
authors.lastname: Campbell
authors.affiliation: Section Biomedical Imaging, Department of Radiology and Neurology, University Hospital Schleswig-Holstein, Kiel, Germany.
authors.forename: Jaime A
authors.initials: JA
authors.lastname: Peña
authors.affiliation: Section Biomedical Imaging, Department of Radiology and Neurology, University Hospital Schleswig-Holstein, Kiel, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Giravent
authors.affiliation: National Scientific and Technical Research Council (CONICET), National University of the South, Bahía Blanca, Argentina.
authors.forename: Felix
authors.initials: F
authors.lastname: Thomsen
authors.affiliation: Section Biomedical Imaging, Department of Radiology and Neurology, University Hospital Schleswig-Holstein, Kiel, Germany.
authors.forename: Timo
authors.initials: T
authors.lastname: Damm
authors.affiliation: Section Biomedical Imaging, Department of Radiology and Neurology, University Hospital Schleswig-Holstein, Kiel, Germany.
authors.forename: Claus-C
authors.initials: CC
authors.lastname: Glüer
authors.affiliation: Section Biomedical Imaging, Department of Radiology and Neurology, University Hospital Schleswig-Holstein, Kiel, Germany.|Institut und Poliklinik für Diagnostische Radiologie, Uniklinik Köln, Köln, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Borggrefe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D015519:Bone Density; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016017:Odds Ratio; D014057:Tomography, X-Ray Computed
keywords: BIOMECHANICS; BONE QCT; PRIMARY TUMORS OF BONE AND CARTILAGE; RADIOLOGY