Differences in perfusion parameters between upper and lower lumbar vertebral segments with dynamic contrast-enhanced MRI (DCE MRI)

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Purpose: To investigate differences in perfusion profiles between degenerative endplate marrow changes and normal vertebral marrow in relation to spinal level, age, and sex with dynamic contrast-enhanced magnetic resonance imaging (DCE MRI).Materials and Methods: Ninety-two consecutive patients referred for evaluation of low back pain or sciatica, without history of malignant or chronic disease, underwent conventional and DCE MRI of the lumbosacral spine. Fifty-two of them demonstrated degenerative endplate marrow changes. Regions of interest were placed on sites of normal marrow (group A) and degenerative changes (group B) on subtracted images. Fitted time-intensity curves (fTICs) were generated and evaluated for curve pattern. Both groups were stratified into upper (L1-L2) and lower (L3-I1) levels, males and females younger or older than 50 years. Perfusion parameters were calculated and statistically compared for both groups and subgroups. Receiver operator curve (ROC) analysis was also performed.Results: Two fTIC patterns were identified. Perfusion parameters of degenerative changes and normal marrow differed significantly, even when groups were stratified for spinal level, age, and sex (P < 0.05). A time to peak value >108 seconds was characteristic for degenerative changes with sensitivity 69.5% and specificity 84.6%.Conclusion: DCE MRI profiles of degenerative endplate marrow changes of the lumbosacral spine differ significantly from normal marrow regardless of spinal level, age, or sex.

Section: Discussionmentioning

confidence: 99%

Section: Mri Data Handling and Image Analysismentioning

confidence: 99%

Section: Mri Data Handling and Image Analysismentioning

confidence: 99%

“…Maximum dynamic contrast enhancement (DCE max ) is depicted by the maximum function of the fTIC. Finally, the ratio WIN/TMSP (WTSP) reflects the rate of change of WIN values (9,13).…”

Section: Mri Data Handling and Image Analysismentioning

confidence: 99%

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confidence: 99%

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Degenerative endplate changes of the lumbosacral spine: Dynamic contrast‐enhanced MRI profiles related to age, sex, and spinal level

Savvopoulou

Maris²,

Κουρέας

et al. 2011

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Modified brix model analysis of bone perfusion in subjects of varying bone mineral density

Ting

Griffith

Yeung

et al. 2010

Purpose: To apply pharmacokinetic modeling to the investigation of bone perfusion in subjects of varying bone mineral density. Materials and Methods:This study re-analyzed previous experimental data. A modified pharmacokinetic model was applied to data obtained from two prior studies of dynamic contrast-enhanced MR imaging of L3 vertebral body in 165 subjects (65 males, 100 females), classified into three groups (normal, osteopenia, and osteoporosis) according to bone mineral density. Three parameters, amplitude A, exchange rate (k ep ), and elimination rate (k el ), were obtained by fitting the signal intensity to the pharmacokinetic model. These parameters were compared across the three groups for males and females, respectively.Results: Perfusion parameters, amplitude A was found to be reduced in osteoporotic subjects with additional, though less pronounced, reductions found in the permeability constant (A*k ep ) and the elimination rate (k el ). Increased marrow fat content was found in osteoporotic bone, which helped to partially explain the observed reduction in interstitial space.Conclusion: By pharmacokinetic model, bone perfusion can be quantitatively analyzed with alteration in functional parameters related to microcirculation in subjects of varying bone mineral density. Developing bone marrow specific pharmacokinetic models should help to deepen knowledge of physiological and pathological perfusion changes occurring in bone. OSTEOPOROSIS IS THE most common metabolic bone disorder (1). Bone loss and structural deterioration of bone tissue begins from the time of peak bone mass accelerating in the elderly particularly in postmenopausal females. This loss and structural deterioration of bone proceeds until bone strength becomes sufficiently poor as to increase susceptibility to fracture at which stage the osteoporotic state has been reached. Clinical, epidemiological, and histological studies have indicated a link between vascular disease and osteoporosis (2-5). Dynamic contrast-enhanced MRI (DCE-MRI) provides a more direct measure of bone perfusion. Bone perfusion is a physiological process, which can be assessed by DCE-MRI. Bone perfusion refers to a diverse process dependent on factors such as tissue blood flow, capillary capacitance and permeability, interstitial diffusion, interstitial space volume, and venous return (6,7). DCE-MRI studies have shown how semi-quantitative perfusion parameters (enhancement maximum, E max , and enhancement slope, E slope ) are consistently reduced in osteopenic and osteoporotic bone compared with normal bone mineral density (BMD) subjects (8-10). These semiquantitative parameters are robust and easy to measure, but they are limited in the information they provide regarding the physiological processes affected. Knowledge of the physiological processes behind altered bone perfusion can be improved by obtaining a more detailed assessment of bone perfusion kinetics beyond that provided by E max and E slope . This more detailed evaluation can be obtained by pharmacokinetic...

Quantitative analysis of vertebral bone marrow perfusion using dynamic contrast‐enhanced MRI: Initial results in osteoporotic patients with acute vertebral fracture

Biffar¹,

Schmidt

Sourbron

et al. 2011

Purpose: To evaluate the potential of quantitative dynamic contrast-enhanced MRI (DCE-MRI) in vertebral bone marrow (vBM) of patients with acute osteoporotic vertebral compression fractures. Materials and Methods:Twenty-six patients with acute osteoporotic fractures (16 female, 10 male, median age 72, range 48-89) and 10 subjects without known history of osteoporosis (6 female, 4 male, median 65, range 31-77) were examined 2D-DCE-MRI. Region of interest (ROI) data in fractured (n ¼ 26) and normal-appearing vertebrae (n ¼ 271) were analyzed with a two-compartment tracer-kinetic-model, providing estimates of at least three independent parameters: plasma flow (PF), plasma volume (PV), and extraction flow (EF). Parameters were correlated with dual x-ray absorptiometry (DXA) (n ¼ 15) and quantitative computed tomography (QCT) densitometry (n ¼ 10).Results: Mean PF was significantly higher in fractures than in normal-appearing vertebrae (69.37 vs. 11.72 mL/ 100 mL/min). Similarly, mean PV and EF differed significantly. Mean PF was significantly decreased in normalappearing vBM osteoporotic patients compared to the control group. Mean PF and PV were significantly decreased in lumbar compared to thoracic vertebrae. PV showed a significant correlation with QCT.Conclusion: Perfusion parameters were decreased significantly in normal-appearing vBM of patients. Furthermore, significant perfusion alterations were observed in acute osteoporotic vertebral fractures compared to normalappearing vertebrae.