Immobilization using dental material casts facilitates accurate serial and multimodality small animal imaging

Haney, Chad R.; Fan, Xiaobing; Parasca, Adrian D.; Karczmar, Gregory S.; Halpern, Howard J.; Pelizzari, Charles A.

doi:10.1002/cmr.b.20108

Cited by 25 publications

(17 citation statements)

References 6 publications

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“…It has been shown previously that the cast does not affect image quality. 25 The complete experiment, including the animal preparation, could be up to 3 h long. We carefully maintained a steady level of anesthesia and monitored the breathing rate and temperature during the experiment to ensure that the oxygenation level of the tissues was similar for all measurements.…”

Section: Approximately 10mentioning

confidence: 99%

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Comparison of 250 MHz electron spin echo and continuous wave oxygen EPR imaging methods for in vivo applications

Epel¹,

Sundramoorthy²,

Barth³

et al. 2011

Medical Physics

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Purpose:The authors compare two electron paramagnetic resonance imaging modalities at 250 MHz to determine advantages and disadvantages of those modalities for in vivo oxygen imaging. Methods: Electron spin echo ͑ESE͒ and continuous wave ͑CW͒ methodologies were used to obtain three-dimensional images of a narrow linewidth, water soluble, nontoxic oxygen-sensitive trityl molecule OX063 in vitro and in vivo. The authors also examined sequential images obtained from the same animal injected intravenously with trityl spin probe to determine temporal stability of methodologies. Results: A study of phantoms with different oxygen concentrations revealed a threefold advantage of the ESE methodology in terms of reduced imaging time and more precise oxygen resolution for samples with less than 70 torr oxygen partial pressure. Above ϳ100 torr, CW performed better. The images produced by both methodologies showed pO 2 distributions with similar mean values. However, ESE images demonstrated superior performance in low pO 2 regions while missing voxels in high pO 2 regions. Conclusions: ESE and CW have different areas of applicability. ESE is superior for hypoxia studies in tumors.

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Section: Approximately 10mentioning

confidence: 99%

“…These fiducials are embedded in the same vinyl polysiloxane dental material cast holding the leg. 25 This defines a coordinate transformation from the MRI image that allows us to import anatomic information, especially the tumor boundary, to the ESE image.…”

Section: Iih Image Registrationmentioning

confidence: 99%

Comparison of 250 MHz electron spin echo and continuous wave oxygen EPR imaging methods for in vivo applications

Epel¹,

Sundramoorthy²,

Barth³

et al. 2011

Medical Physics

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“…The anesthetized animal was immobilized with a partial circumference vinyl polysiloxane cast (GC Dental Products, Kasugai, Japan) [40]. OX063 was injected IV 0.56 mmol/kg followed by infusion at 0.63 mmol/kg/hr.…”

Section: Methodsmentioning

confidence: 99%

Fast dynamic electron paramagnetic resonance (EPR) oxygen imaging using low-rank tensors

Christodoulou

Redler

Clifford

et al. 2016

Journal of Magnetic Resonance

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Hypoxic tumors are resistant to radiotherapy, motivating the development of tools to image local oxygen concentrations. It is generally believed that stable or chronic hypoxia is the source of resistance, but more recent work suggests a role for transient hypoxia. Conventional EPR imaging (EPRI) is capable of imaging tissue pO2 in vivo, with high pO2 resolution and 1 mm spatial resolution but low imaging speed (10 min temporal resolution for T1-based pO2 mapping), which makes it difficult to investigate the oxygen changes, e.g. transient hypoxia. Here we describe a new imaging method which accelerates dynamic EPR oxygen imaging, allowing 3D imaging at 2 frames per minute, fast enough to image transient hypoxia at the “speed limit” of observed pO2 change. The method centers on a low-rank tensor model that decouples the tradeoff between imaging speed, spatial coverage/resolution, and number of inversion times (pO2 accuracy). We present a specialized sparse sampling strategy and image reconstruction algorithm for use with this model. The quality and utility of the method is demonstrated in simulations and in vivo experiments in tumor bearing mice.

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“…For tumor definition, an anatomic MRI image was taken prior to oxygen image. EPR and MRI images were registered with the help of fiducials embedded into a vinyl polysiloxane dental mold [6]. The ArbuzGUI MATLAB toolbox developed by the Center for EPR Imaging in vivo Physiology at the University of Chicago was used for image registration.…”

Section: Methodsmentioning

confidence: 99%

Approaching Oxygen-Guided Intensity-Modulated Radiation Therapy

Epel

Redler

Pelizzari

et al. 2016

Advances in Experimental Medicine and Biology

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The outcome of cancer radiation treatment is strongly correlated with tumor oxygenation. The aim of this study is to use oxygen tension distributions in tumors obtained using Electron Paramagnetic Resonance (EPR) imaging to devise better tumor radiation treatment. The proposed radiation plan is delivered in two steps. In the first step, a uniform 50% tumor control dose (TCD50) is delivered to the whole tumor. For the second step an additional dose boost is delivered to radioresistant, hypoxic tumor regions. FSa fibrosarcomas grown in the gastrocnemius of the legs of C3H mice were used. Oxygen tension images were obtained using a 250 MHz pulse imager and injectable partially deuterated trityl OX63 (OX71) spin probe. Radiation was delivered with a novel animal intensity modulated radiation therapy (IMRT) XRAD225Cx microCT/radiation therapy delivery system. In a simplified scheme for boost dose delivery, the boost area is approximated by a sphere, whose radius and position are determined using an EPR O2 image. The sphere that irradiates the largest fraction of hypoxic voxels in the tumor was chosen using an algorithm based on Receiver Operator Characteristic (ROC) analysis. We used the fraction of irradiated hypoxic volume as the true positive determinant and the fraction of irradiated normoxic volume as the false positive determinant in the terms of that analysis. The most efficient treatment is the one that demonstrates the shortest distance from the ROC curve to the upper left corner of the ROC plot. The boost dose corresponds to the difference between TCD90 and TCD50 values. For the control experiment an identical radiation dose to the normoxic tumor area is delivered.

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Immobilization using dental material casts facilitates accurate serial and multimodality small animal imaging

Cited by 25 publications

References 6 publications

Comparison of 250 MHz electron spin echo and continuous wave oxygen EPR imaging methods for in vivo applications

Comparison of 250 MHz electron spin echo and continuous wave oxygen EPR imaging methods for in vivo applications

Fast dynamic electron paramagnetic resonance (EPR) oxygen imaging using low-rank tensors

Approaching Oxygen-Guided Intensity-Modulated Radiation Therapy

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