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Teriparatide treatment increases Hounsfield units in the lumbar spine out of proportion to DEXA changes

Presented at the 2019 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves

Anthony L. Mikula, Ross C. Puffer, Jeffery D. St. Jeor, James T. Bernatz, Jeremy L. Fogelson, A. Noelle Larson, Ahmad Nassr, Arjun S. Sebastian, Brett A. Freedman, Bradford L. Currier, Mohamad Bydon, Michael J. Yaszemski, Paul A. Anderson and Benjamin D. Elder

, 17 and often the subjective finding of improved bone quality intraoperatively is not supported by DEXA results. Hounsfield units (HU) are a standardized measurement for radiodensity obtained from CT scans and are an alternative way to measure bone health. HU have been shown to correlate with BMD as measured by DEXA. 6 , 14 The objective of this study was to determine if teriparatide significantly improves bone quality, as measured by HU, and how that change compares to BMD as measured on DEXA. Methods Following approval from the institutional review board (IRB no

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Da Zou, Weishi Li, Fei Xu and Guohong Du

first to fourth lumbar vertebrae (L1–4) and hips. 4 Based on the positive correlation between the BMD of different sites in the same patient, the BMD of the S1 body can usually only be estimated via DXA rather than measured directly. 19 Moreover, DXA can overestimate the BMD of the lumbar spine and cause a missed diagnosis of osteoporosis in lumbar degenerative disease, especially for degenerative lumbar scoliosis, which is a more common disease needing fusion to S1. 2 , 10 , 11 Since 2011, the method of using Hounsfield units (HUs) from clinical CT scanning has

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Da Zou, Aikeremujiang Muheremu, Zhuoran Sun, Woquan Zhong, Shuai Jiang and Weishi Li

density (BMD), is the most frequently reported risk factor for screw loosening. 10 Although the reported incidence of screw loosening varies among different published studies, in patients with osteoporosis the risk of screw loosening is twice that of patients without osteoporosis, and 6.3%–15.6% of patients with screw loosening require revision surgery. 3 , 8 , 20 However, only a handful of clinical studies have reported on the relation between low BMD and pedicle screw loosening. 8 BMD measured in Hounsfield units (HU) on CT is used in the evaluation of BMD and can

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Eitan M. Kohan, Venu M. Nemani, Stuart Hershman, Daniel G. Kang and Michael P. Kelly

bone health of these patients preoperatively. Current practices use femoral neck DEXA scans to more accurately measure BMD and guide therapy in this population. Hounsfield unit (HU) measurements obtained from CT scans correlate to lumbar spine BMD in cases of spinal trauma and vertebral compression fractures. 33 This modality allows for assessment of osteoporosis and fracture risk without the need for further imaging via DEXA. In degenerative lumbar spine surgery, higher HU measurements are associated with lower rates of pseudarthrosis. 34 HU measurements may also

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Barry N. French and Arthur B. Dublin

. The posterior fossa cuts demonstrated an area of visually increased density (54 Hounsfield units * ) with the shape of brain stem and cerebellar hemispheres surrounding the fourth ventricle ( Fig. 1 ). The space between the occipital bone and the visually dense cerebellum and brain stem had a density of 42 Hounsfield units, as did the supratentorial cerebral white matter. Contrast enhancement increased the density of the cerebellum and brain stem to 69 Hounsfield units with no change in the density of supratentorial cerebral white matter or the material capping the

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Shobu Shibata and Kazuo Mori

meningitis developed from a subcutaneous abscess at the site of the wound. After successful treatment of the meningitis, hydrocephalus developed and a ventriculoperitoneal shunt was placed. The patient later developed an intracerebral hematoma and ventriculitis, and died in September, 1979. Pathological Course Figure 2 shows the changes in the tumor before, during, and after irradiation. Following the delivery of 2750 rads, the tumor had shrunk to 63% of its preirradiation size and the Hounsfield units on the nonenhanced CT scans had decreased from 57 to 15. After

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

quality of life, which are associated with substantial health care costs exceeding $17 billion (US dollars) annually. 3 Dual x-ray absorptiometry (DXA) is currently the standard for assessing bone mineral density (BMD) and has been correlated with fracture risk and treatment efficacy. 21 While useful for assessing osteopenia or osteoporosis, 1 it is not without methodological limitations. 37 The use of Hounsfield units (HUs) from CT scanning to assess regional BMD of the spine has recently been described, 30 with several subsequent studies exploring its utility

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Hideo Hiratsuka, Hitoshi Tabata, Shin Tsuruoka, Masaru Aoyagi, Kodai Okada and Yutaka Inaba

if necessary 48 hours after the injection of metrizamide into the ventricle. Temporal changes of Hounsfield units in the regions of interest in the brain were followed and correlated with migration of metrizamide into the periventricular white matter by tracing the linear attenuation profile. Four of the dogs were killed immediately after CT ventriculography; 15 to 100 mg of tissue from various parts of the brain was sampled, and the iodine concentration was measured in each by the cerate-arsenite method 5 and compared against the CT image. In seven other dogs

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Tetsuhiro Iguchi, Aritetsu Kanemura, Akira Kurihara, Koichi Kasahara, Shinichi Yoshiya, Minoru Doita and Kotaro Nishida

alone correlated with bone—spacer bonding. Postoperative AP diameters in the union group were significantly smaller than those in the nonunion group, and this relationship was also true in the regrowth and the absent regrowth groups ( Fig. 5 lower ). Hounsfield Unit Value The CT number of ROI 1 ( Fig. 3 ) showed a significant positive correlation (r = 0.68) with time after surgery ( Fig. 6 ). This finding was true in every ROI (ROI 2, r = 0.64; 3, r = 0.79; 4, r = 0.7; 5, r = 0.69; and 6, r = 0.49). The mean CT values (± standard deviations) of the six

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Kazuo Mizoi, Takashi Yoshimoto, Akira Takahashi, Satoru Fujiwara, Keiji Koshu and Takayuki Sugawara

105 patients who underwent direct operations within 48 hours of SAH and whose computerized tomography (CT) findings were classified as Fisher CT Group 3. 9 The tPA group comprised patients in whom the subarachnoid hematoma gave mean CT scores of more than 75 Hounsfield units (HU); in these cases, tPA was administered intrathecally. The control group comprised patients with mean CT scores below 75 HU, and these underwent cisternal drainage only. The CT density of the hematomas was investigated in all patients by means of region-of-interest analysis. A total of six