Use of computed tomography for assessing bone mineral density

Schreiber, Joseph J.; Anderson, Paul A.; Hsu, Wellington K.

doi:10.3171/2014.5.focus1483

Cited by 203 publications

(149 citation statements)

References 35 publications

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“…[26] Furthermore, the related research had reported that the average HU value of spine depending on different age groups decreased as the patients’ age increased and the differences in HU values from L1 to 4th Lumbar were significant among different age groups. [27, 35, 36] Therefore, our finding suggests that each 3D printing technique has its own special advantage in terms of the HU value that depends on the patient’s age and it also demonstrated that careful selection of the 3D printing technique and printing materials is required since even when the same material, which is known to have a similar density to the human spine, was applied for 3D printing, the calculated HU values from two different 3D printed spine phantom sets were different.…”

Section: Discussionmentioning

confidence: 99%

Characterization of 3D printing techniques: Toward patient specific quality assurance spine-shaped phantom for stereotactic body radiation therapy

Kim

Lee

et al. 2017

PLoS ONE

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Development and comparison of spine-shaped phantoms generated by two different 3D-printing technologies, digital light processing (DLP) and Polyjet has been purposed to utilize in patient-specific quality assurance (QA) of stereotactic body radiation treatment. The developed 3D-printed spine QA phantom consisted of an acrylic body phantom and a 3D-printed spine shaped object. DLP and Polyjet 3D printers using a high-density acrylic polymer were employed to produce spine-shaped phantoms based on CT images. Image fusion was performed to evaluate the reproducibility of our phantom, and the Hounsfield units (HUs) were measured based on each CT image. Two different intensity-modulated radiotherapy plans based on both CT phantom image sets from the two printed spine-shaped phantoms with acrylic body phantoms were designed to deliver 16 Gy dose to the planning target volume (PTV) and were compared for target coverage and normal organ-sparing. Image fusion demonstrated good reproducibility of the developed phantom. The HU values of the DLP- and Polyjet-printed spine vertebrae differed by 54.3 on average. The PTV Dmax dose for the DLP-generated phantom was about 1.488 Gy higher than that for the Polyjet-generated phantom. The organs at risk received a lower dose for the 3D printed spine-shaped phantom image using the DLP technique than for the phantom image using the Polyjet technique. Despite using the same material for printing the spine-shaped phantom, these phantoms generated by different 3D printing techniques, DLP and Polyjet, showed different HU values and these differently appearing HU values according to the printing technique could be an extra consideration for developing the 3D printed spine-shaped phantom depending on the patient’s age and the density of the spinal bone. Therefore, the 3D printing technique and materials should be carefully chosen by taking into account the condition of the patient in order to accurately produce 3D printed patient-specific QA phantom.

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Section: Discussionmentioning

confidence: 99%

Characterization of 3D printing techniques: Toward patient specific quality assurance spine-shaped phantom for stereotactic body radiation therapy

Kim

Lee

et al. 2017

PLoS ONE

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“…First, we used CTderived HU to estimate the degree of BMD reduction. Although the gold standard for measuring BMD is the DEXA scan, several studies demonstrate the utility of diagnostic CT scan in providing reliable estimates for regional bone strength and BMD [10][11][12][13]. Secondly, this study is a retrospective review of patients treated at a single institution.…”

Section: Discussionmentioning

confidence: 99%

“…Although dual-energy X-ray absorptiometry (DEXA) serves as the gold standard for BMD quantification, several studies have determined that the BMD provided by DEXA has a strong correlation with CT-derived Hounsfield units (HU), can provide reliable estimates for regional bone strength and BMD, and accurately rule out osteoporosis with better than 90% sensitivity [10][11][12][13]. Since diagnostic CT scans are ordered routinely to monitor response to treatments, we can utilize CT-derived HU to monitor BMD in patients, while avoiding the need for additional DEXA imaging and improving resource utilization.…”

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confidence: 99%

Bone Mineral Density Loss in Thoracic and Lumbar Vertebrae Following Radiation for Abdominal Cancers

Jung

Wei

Sehgal³

et al. 2016

International Journal of Radiation Oncology*Biology*Physics

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a b s t r a c tPurpose: To investigate the relationship between abdominal chemoradiation (CRT) for locally advanced cancers and bone mineral density (BMD) reduction in the vertebral spine. Materials and methods: Data from 272 patients who underwent abdominal radiation therapy from January 1997 to May 2015 were retrospectively reviewed. Forty-two patients received computed tomography (CT) scans of the abdomen prior to initiation and at least twice after radiation therapy. Bone attenuation (in Hounsfield unit) (HU) measurements were collected for each vertebral level from T7 to L5 using sagittal CT images. Radiation point dose was obtained at each mid-vertebral body from the radiation treatment plan. Percent change in bone attenuation (D%HU) between baseline and post-radiation therapy were computed for each vertebral body. The D%HU was compared against radiation dose using Pearson's linear correlation. Results: Abdominal radiotherapy caused significant reduction in vertebral BMD as measured by HU. Patients who received only chemotherapy did not show changes in their BMD in this study. The D%HU was significantly correlated with the radiation point dose to the vertebral body (R = À0.472, P < 0.001) within 4-8 months following RT. The same relationship persisted in subsequent follow up scans 9 months following RT (R = À0.578, P < 0.001). Based on the result of linear regression, 5 Gy, 15 Gy, 25 Gy, 35 Gy, and 45 Gy caused 21.7%, 31.1%, 40.5%, 49.9%, and 59.3% decrease in HU following RT, respectively. Our generalized linear model showed that pre-RT HU had a positive effect (b = 0.830) on determining post-RT HU, while number of months post RT (b = À0.213) and radiation point dose (b = À1.475) had a negative effect. A comparison of the predicted versus actual HU showed significant correlation (R = 0.883, P < 0.001) with the slope of the best linear fit = 0.81. Our model's predicted HU were within ±20 HU of the actual value in 53% of cases, 70% of the predictions were within ±30 HU, 81% were within ±40 HU, and 90% were within ±50 HU of the actual post-RT HU. Four of 42 patients were found to have vertebral body compression fractures in the field of radiation. Vertebral body insufficiency and compression fractures are most commonly caused by osteoporosis, an age-related and systemic skeletal disorder characterized by compromised bone strength and low bone mineral density [1]. Although, most fractures are asymptomatic, the degree of BMD loss, location of the fracture, and secondary osteoporosis from underlying medical condition including chemotherapy may make an asymptomatic, stable fracture more prone to progressive collapse causing pain, loss of mobility, and spinal cord compression [2]. The overall morbidity of vertebral body compression fractures is significant, and women diagnosed with compression fractures have a 15% higher mortality rate than matched controls [3].Irradiation of normal, non-malignant bone results in small vessel damage leading to microcirculatory occlusion, marrow hypocellularity from death of osteo...

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“…Одним из наиболее важных факторов, вли-яющих на сохранение стабильности имплантов после декомпрессивно-стабилизирующих опера-тивных вмешательствах, является качество кост-ной ткани, что было неоднократно подтвержде-но результатами исследований [6,13,14]. Тем не менее способы оценки костной плотности в опубликованных работах отличаются: чаще всего с ýтой целью применялась денситометрия, коли-чественная компьютерная томография, и радио-денсивность костной ткани, определенная при КТ, использовались реже [6,7,14].…”

Section: результаты и обсуждениеunclassified

Risk Factors of Pedicle Fixation Instability at Patients With Degenerative Lumbar Spine Pathology

Bokov¹,

Млявых²,

Алейник³

et al. 2016

Bûll. sib. med.

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Приволжский федеральный медицинский исследовательский центр, г. Нижний Новгород РЕЗЮМЕЦель исследования -оценить факторы риска дестабилизации транспедикулярного инструментария после выполнения декомпрессивно-стабилизирующих вмешательств у пациентов с дегенеративной пато-логией поясничного отдела позвоночника.Материал и методы. Исследование является нерандомизированным продольным проспективным, исследованы результаты наиболее распространенных декомпрессивно-стабилизирующих оперативных вмешательств у 130 пациентов с дегенеративными заболеваниями поясничного отдела позвоночника. Минимальный срок наблюдения -18 мес. Пациентам перед операцией проводилась компьютерная томография (КТ) поясничного отдела позвоночника и определялась радиоденсивность костной ткани. Пациентам выполнялась микрохирургическая декомпрессия корешков спинного мозга с применением транспедикулярной фиксации в сочетании с межтеловым спондилодезом или без него. В послеопера-ционном периоде регистрировались все случаи с рентгенографическими признаками дестабилизации винтов. Используя логистический регрессионный анализ, определялась зависимость частоты расшаты-вания транспедикулярных винтов от радиоденсивности губчатой костной ткани позвонка по данным КТ, степени резекции костно-связочного аппарата в ходе декомпрессии, протяженности фиксации и биомеханических нарушений, обусловленных неполной редукцией позвонка. Также определялось влияние межтелового спондилодеза и неоднородности исследуемой группы пациентов по диагнозу.Результаты. Снижение радиоденсивности костной ткани, увеличение протяженности фиксации и эк-стенсивности декомпрессии сопряжены с повышенным риском развития нестабильности транспедику-лярного инструментария. Такие признаки, как ляминэктомия, отсутствие межтелового спондилодеза в пределах фиксированной области, включение в фиксированную область сегмента L5-S1 и фактор био-механического нарушения в результате неполной редукции позвонка не оказывали влияния на частоту расшатывания винтов. Незначимым оказалось влияние фактора неоднородности исследуемой группы. Общая пригодность регрессионной модели ¹ 2 = 67,57851; p < 0,0001. Модель правильно классифици-рует 81,5% наблюдений, чувствительность ее составила 77,4%, специфичность -85,3%.Çаключение. Радиоденсивность костной ткани по результатам КТ является значимым прогностическим фактором развития нестабильности имплантов. Существенными факторами риска расшатывания винтов также являются увеличение протяженности ригидной фиксации и экстенсивная резекция дугоотростча-тых суставов и связочного аппарата позвоночно-двигательных сегментов. Перечисленные факторы риска необходимо учитывать при планировании декомпрессивно-стабилизирующих вмешательств, особенно у пациентов пожилого возраста.КЛЮЧЕВЫЕ СЛОВА: транспедикулярная фиксация, нестабильность имплантов, компьютерная томо-графия, дегенеративные заболевания поясничного отдела позвоночника.

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Use of computed tomography for assessing bone mineral density

Cited by 203 publications

References 35 publications

Characterization of 3D printing techniques: Toward patient specific quality assurance spine-shaped phantom for stereotactic body radiation therapy

Characterization of 3D printing techniques: Toward patient specific quality assurance spine-shaped phantom for stereotactic body radiation therapy

Bone Mineral Density Loss in Thoracic and Lumbar Vertebrae Following Radiation for Abdominal Cancers

Risk Factors of Pedicle Fixation Instability at Patients With Degenerative Lumbar Spine Pathology

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