This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.
ABSTRACT Breast cancers metastasize to the bone, lung, brain and liver and mortality from breast ... more ABSTRACT Breast cancers metastasize to the bone, lung, brain and liver and mortality from breast cancer is due to metastases. Drugs that inhibit metastasis in particular of triple negative (TN) breast cancers, more sensitive methods to image metastases and imaging biomarkers to monitor response to these drugs at sites of metastasis are needed to reduce mortality. The type I insulin-like growth factor receptor (IGF1R) regulates metastasis and drugs targeting IGF1R and or insulin receptor inhibit metastasis of TN breast cancer cells in mouse models. The initial clinical trials of these drugs have not been very successful and point to the need to develop imaging biomarkers for this therapy. While MRI is a powerful tool for detecting and imaging cancer, its utility in imaging metastasis to the lung is limited due to the challenges of lung MRI with conventional 3D gradient echo (GRE). MRI does not visualize lung well, mainly due to the abundance of air-tissue interfaces, which cause the MR signal to decay too rapidly for conventional MRI pulse sequences to capture. Clinically lung metastases are monitored by CT or PET but exposure of patients to ionizing radiation is a concern and problematic in longitudinal studies monitoring response to a targeted drug. Further MRI can also be useful in measuring metabolite levels using MR spectroscopy (MRS). Therefore, we evaluated the capability of a novel MR sequence called sweep imaging with Fourier transformation (SWIFT), where the data is acquired concurrently with the radiofrequency pulse, to detect breast cancer metastases to lung and test if inhibition of metastases by an IGF1R targeted drug can be monitored by SWIFT. We used the tail vein injection model of breast cancer metastasis with MDA-MB-231-LM2, a lung-seeking metastatic TN breast cancer cell line. Lung metastases were monitored with bioluminescence imaging (BLI) and MRI every week. MRI was done with two pulse sequences: SWIFT (with a short echo time or TE∼3 μs) and GRE (with a longer TE = 2.2 ms). SWIFT showed significantly higher sensitivity in detecting signals from lung parenchyma compared to GRE and structural information was visible in the area of the lungs. Metastatic tumor growth in the lung induced a progressive increase in signal from the lung parenchyma in SWIFT images. MIP images from SWIFT clearly visualized the lung vascular structures and their disruption due to progression of breast cancer metastasis. To test if SWIFT can also be useful in monitoring inhibition of metastases, mice injected with cells were treated with either vehicle or an IGF1R inhibitor (huEM164) twice a week. When inhibition of metastases in the huEM164 treated group compared to the vehicle group was evident by BLI, MR images were acquired. SWIFT was sensitive in detecting the inhibition of metastases by the IGF1R antibody. Our data show that high sensitivity to fast-decaying signals and tolerance to the magnetic susceptibility in SWIFT enhance the capability to detect signal and structural changes in the lung parenchyma and vasculature due to metastasis of breast cancer. Further, SWIFT was also sensitive to monitor inhibition of metastasis in response to IGF1R targeted drugs.
Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine, Jan 20, 2015
Methods designed to image fast-relaxing spins, such as sweep imaging with Fourier transformation ... more Methods designed to image fast-relaxing spins, such as sweep imaging with Fourier transformation (SWIFT), often utilize high excitation bandwidth and duty cycle, and in some applications the optimal flip angle cannot be used without exceeding safe specific absorption rate (SAR) levels. The aim is to reduce SAR and increase the flexibility of SWIFT by applying time-varying gradient-modulation (GM). The modified sequence is called GM-SWIFT. The method known as gradient-modulated offset independent adiabaticity was used to modulate the radiofrequency (RF) pulse and gradients. An expanded correlation algorithm was developed for GM-SWIFT to correct the phase and scale effects. Simulations and phantom and in vivo human experiments were performed to verify the correlation algorithm and to evaluate imaging performance. GM-SWIFT reduces SAR, RF amplitude, and acquisition time by up to 90%, 70%, and 45%, respectively, while maintaining image quality. The choice of GM parameter influences the ...
Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine, Jan 11, 2014
To evaluate the capability of longitudinal MR scans using sweep imaging with Fourier transformati... more To evaluate the capability of longitudinal MR scans using sweep imaging with Fourier transformation (SWIFT) to detect breast cancer metastasis to the lung in mice. Mice with breast cancer metastatic to the lung were generated by tail vein injection of MDA-MB-231-LM2 cells. Thereafter, MR imaging was performed every week using three different pulse sequences: SWIFT [echo time (TE) ∼3 μs], concurrent dephasing and excitation (CODE; TE ∼300 μs), and three-dimensional (3D) gradient echo (GRE; TE = 2.2 ms). Motion during the long SWIFT MR scans was compensated for by rigid-body motion correction. Maximum intensity projection (MIP) images were generated to visualize changes in lung vascular structures during the development and growth of metastases. SWIFT MRI was more sensitive to signals from the lung parenchyma than CODE or 3D GRE MRI. Metastatic tumor growth in the lungs induced a progressive increase in intensity of parenchymal signals in SWIFT images. MIP images from SWIFT clearly vi...
Archives of Otolaryngology–Head & Neck Surgery, 2011
Objective-Current imaging techniques are often sub-optimal for the detection of mandibular invasi... more Objective-Current imaging techniques are often sub-optimal for the detection of mandibular invasion by squamous cell carcinoma. The aim of this study was to determine the feasibility of a magnetic resonance imaging (MRI) based technique known as Sweep Imaging with Fourier Transform (SWIFT) to visualize the structural changes of intra-mandibular anatomy during invasion.
A method for generating a magnetic resonance image includes applying a radio frequency (RF) pulse... more A method for generating a magnetic resonance image includes applying a radio frequency (RF) pulse to a specimen. The method includes modulating a spatially varying magnetic field to impart an angular velocity to a trajectory of a region of resonance relative to the specimen. The method includes acquiring data corresponding to the region of reso nance and reconstructing a representation of the specimen based on the data.
Target Audience Researchers, Technicians, and Clinician/Scientists interested in emerging breast ... more Target Audience Researchers, Technicians, and Clinician/Scientists interested in emerging breast imaging methodology, and related applications.
A method includes applying a pulse train to a spin system in a scanner. The pulse train has a plu... more A method includes applying a pulse train to a spin system in a scanner. The pulse train has a plurality of discontinuities in a time domain. The method includes receiving a response from the spin system. The response corresponds to a gated signal. The method includes accessing a correction factor corresponding to the scanner. The method includes calculating a correction to the response based on the correction factor. The method includes generating an output based on the correction.
Introduction: Lung and especially lung parenchyma are difficult to image with MRI 1 . T 2 * times... more Introduction: Lung and especially lung parenchyma are difficult to image with MRI 1 . T 2 * times are in the sub-millisecond range and may require specialized hardware and methods for optimum visualization or quantitative information 1,6-8 . Many lung pathologies such as inflamation (asthma), primary and metastatic neoplasms (cancer) would benefit from robust and high SNR methodologies. For example Kuethe et al. 2 have shown excellent results in rat lung with an optimized radial FID based sequence. We demonstrate here, for the first time, free breathing prospectively gated 1 H SWIFT images of the mouse lung. Lung parenchyma has significant signal and information content while bronchi appear dark. Methods: SWIFT is a novel 3D radial imaging sequence utilizing gapped frequencyswept pulse excitation and nearly simultaneous signal acquisition in the time between the gaps 3,4 . SWIFT utilizes the correlation method 5 which removes phase differences due to the time of excitation and produces FID data (k-space spokes) as if the spokes were simultaneously excited by a short duration pulse. SWIFT has an intrinsically short dead-time, at present hardware-limited to ~2-4 μs. This provides sensitivity to very fast relaxing spins (short T 2 or T 2 * ) similar to BLAST/RUFIS or UTE (Ultrashort TE) sequences 2,6-8 .
Distant dipolar field (DDF)-based nuclear magnetic resonance is an active research area with many... more Distant dipolar field (DDF)-based nuclear magnetic resonance is an active research area with many fundamental properties still not well understood. Already several intriguing applications have developed, like HOMOGENIZED and IDEAL spectroscopy, that allow high resolution spectra to be obtained in inhomogeneous fields, such as in-vivo. The theoretical and experimental research in this thesis concentrates on the fundamental signal properties of
An analytical expression has been developed to describe the effects of T2 relaxation and diffusin... more An analytical expression has been developed to describe the effects of T2 relaxation and diffusing spatially modulated longitudinal spins during the signal build period of an HOMOGENIZED cross peak. Diffusion of the longitudinal spins results in a lengthening of the effective dipolar demagnetization time, delaying the re-phasing of coupled anti-phase states in the quantum picture. In the classical picture the
Purpose To report the results of sweep imaging with Fourier transformation (SWIFT) magnetic reson... more Purpose To report the results of sweep imaging with Fourier transformation (SWIFT) magnetic resonance (MR) imaging for diagnostic breast imaging. Materials and Methods Informed consent was obtained from all participants under one of two institutional review board-approved, HIPAA-compliant protocols. Twelve female patients (age range, 19-54 years; mean age, 41.2 years) and eight normal control subjects (age range, 22-56 years; mean age, 43.2 years) enrolled and completed the study from January 28, 2011, to March 5, 2013. Patients had previous lesions that were Breast Imaging Reporting and Data System 4 and 5 based on mammography and/or ultrasonographic imaging. Contrast-enhanced SWIFT imaging was completed by using a 4-T research MR imaging system. Noncontrast studies were completed in the normal control subjects. One of two sized single-breast SWIFT-compatible transceiver coils was used for nine patients and five controls. Three patients and five control subjects used a SWIFT-compat...
A useful extension to SWIFT (SWeep Imaging with Fourier Transformation) utilizing sidebands of th... more A useful extension to SWIFT (SWeep Imaging with Fourier Transformation) utilizing sidebands of the excitation pulse is introduced. This MRI method, called Multi-Band-SWIFT, achieves much higher bandwidth than standard SWIFT by using multiple segmented excitations (bands) of the field of view. A description of the general idea and variants of the pulse sequence are presented. From simulations and semi-phenomenological theory, estimations of power deposition and signal-to-noise ratio are made. MB-SWIFT and ZTE (zero-TE) sequences are compared based on images of a phantom and human mandible. Multi-Band-SWIFT provides a bridge between SWIFT and ZTE sequences and allows greatly increased excitation and acquisition bandwidths relative to standard SWIFT for the same hardware switching parameters and requires less peak amplitude of the radiofrequency field (or greater flip angle at same peak amplitude) as compared to ZTE. Multi-Band-SWIFT appears to be an attractive extension of SWIFT for certain musculoskeletal and other medical imaging applications, as well as for imaging materials.
A new MRI method is described to acquire a T(2)-weighted image from a single slice in a single sh... more A new MRI method is described to acquire a T(2)-weighted image from a single slice in a single shot. The technique is based on rapid acquisition by sequential excitation and refocusing (RASER). RASER avoids relaxation-related blurring because the magnetization is sequentially refocused in a manner that effectively creates a series of spin echoes with a constant echo time. RASER uses the quadratic phase produced by a frequency-swept chirp pulse to time-encode one dimension of the image. In another implementation the pulse can be used to excite multiple slices with phase-encoding and frequency-encoding in the other two dimensions. The RASER imaging sequence is presented along with single-shot and multislice images, and is compared to conventional spin-echo and echo-planar imaging sequences. A theoretical and empirical analysis of the spatial resolution is presented, and factors in choosing the spatial resolution for different applications are discussed. RASER produces high-quality single-shot images that are expected to be advantageous for a wide range of applications.
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.
ABSTRACT Breast cancers metastasize to the bone, lung, brain and liver and mortality from breast ... more ABSTRACT Breast cancers metastasize to the bone, lung, brain and liver and mortality from breast cancer is due to metastases. Drugs that inhibit metastasis in particular of triple negative (TN) breast cancers, more sensitive methods to image metastases and imaging biomarkers to monitor response to these drugs at sites of metastasis are needed to reduce mortality. The type I insulin-like growth factor receptor (IGF1R) regulates metastasis and drugs targeting IGF1R and or insulin receptor inhibit metastasis of TN breast cancer cells in mouse models. The initial clinical trials of these drugs have not been very successful and point to the need to develop imaging biomarkers for this therapy. While MRI is a powerful tool for detecting and imaging cancer, its utility in imaging metastasis to the lung is limited due to the challenges of lung MRI with conventional 3D gradient echo (GRE). MRI does not visualize lung well, mainly due to the abundance of air-tissue interfaces, which cause the MR signal to decay too rapidly for conventional MRI pulse sequences to capture. Clinically lung metastases are monitored by CT or PET but exposure of patients to ionizing radiation is a concern and problematic in longitudinal studies monitoring response to a targeted drug. Further MRI can also be useful in measuring metabolite levels using MR spectroscopy (MRS). Therefore, we evaluated the capability of a novel MR sequence called sweep imaging with Fourier transformation (SWIFT), where the data is acquired concurrently with the radiofrequency pulse, to detect breast cancer metastases to lung and test if inhibition of metastases by an IGF1R targeted drug can be monitored by SWIFT. We used the tail vein injection model of breast cancer metastasis with MDA-MB-231-LM2, a lung-seeking metastatic TN breast cancer cell line. Lung metastases were monitored with bioluminescence imaging (BLI) and MRI every week. MRI was done with two pulse sequences: SWIFT (with a short echo time or TE∼3 μs) and GRE (with a longer TE = 2.2 ms). SWIFT showed significantly higher sensitivity in detecting signals from lung parenchyma compared to GRE and structural information was visible in the area of the lungs. Metastatic tumor growth in the lung induced a progressive increase in signal from the lung parenchyma in SWIFT images. MIP images from SWIFT clearly visualized the lung vascular structures and their disruption due to progression of breast cancer metastasis. To test if SWIFT can also be useful in monitoring inhibition of metastases, mice injected with cells were treated with either vehicle or an IGF1R inhibitor (huEM164) twice a week. When inhibition of metastases in the huEM164 treated group compared to the vehicle group was evident by BLI, MR images were acquired. SWIFT was sensitive in detecting the inhibition of metastases by the IGF1R antibody. Our data show that high sensitivity to fast-decaying signals and tolerance to the magnetic susceptibility in SWIFT enhance the capability to detect signal and structural changes in the lung parenchyma and vasculature due to metastasis of breast cancer. Further, SWIFT was also sensitive to monitor inhibition of metastasis in response to IGF1R targeted drugs.
Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine, Jan 20, 2015
Methods designed to image fast-relaxing spins, such as sweep imaging with Fourier transformation ... more Methods designed to image fast-relaxing spins, such as sweep imaging with Fourier transformation (SWIFT), often utilize high excitation bandwidth and duty cycle, and in some applications the optimal flip angle cannot be used without exceeding safe specific absorption rate (SAR) levels. The aim is to reduce SAR and increase the flexibility of SWIFT by applying time-varying gradient-modulation (GM). The modified sequence is called GM-SWIFT. The method known as gradient-modulated offset independent adiabaticity was used to modulate the radiofrequency (RF) pulse and gradients. An expanded correlation algorithm was developed for GM-SWIFT to correct the phase and scale effects. Simulations and phantom and in vivo human experiments were performed to verify the correlation algorithm and to evaluate imaging performance. GM-SWIFT reduces SAR, RF amplitude, and acquisition time by up to 90%, 70%, and 45%, respectively, while maintaining image quality. The choice of GM parameter influences the ...
Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine, Jan 11, 2014
To evaluate the capability of longitudinal MR scans using sweep imaging with Fourier transformati... more To evaluate the capability of longitudinal MR scans using sweep imaging with Fourier transformation (SWIFT) to detect breast cancer metastasis to the lung in mice. Mice with breast cancer metastatic to the lung were generated by tail vein injection of MDA-MB-231-LM2 cells. Thereafter, MR imaging was performed every week using three different pulse sequences: SWIFT [echo time (TE) ∼3 μs], concurrent dephasing and excitation (CODE; TE ∼300 μs), and three-dimensional (3D) gradient echo (GRE; TE = 2.2 ms). Motion during the long SWIFT MR scans was compensated for by rigid-body motion correction. Maximum intensity projection (MIP) images were generated to visualize changes in lung vascular structures during the development and growth of metastases. SWIFT MRI was more sensitive to signals from the lung parenchyma than CODE or 3D GRE MRI. Metastatic tumor growth in the lungs induced a progressive increase in intensity of parenchymal signals in SWIFT images. MIP images from SWIFT clearly vi...
Archives of Otolaryngology–Head & Neck Surgery, 2011
Objective-Current imaging techniques are often sub-optimal for the detection of mandibular invasi... more Objective-Current imaging techniques are often sub-optimal for the detection of mandibular invasion by squamous cell carcinoma. The aim of this study was to determine the feasibility of a magnetic resonance imaging (MRI) based technique known as Sweep Imaging with Fourier Transform (SWIFT) to visualize the structural changes of intra-mandibular anatomy during invasion.
A method for generating a magnetic resonance image includes applying a radio frequency (RF) pulse... more A method for generating a magnetic resonance image includes applying a radio frequency (RF) pulse to a specimen. The method includes modulating a spatially varying magnetic field to impart an angular velocity to a trajectory of a region of resonance relative to the specimen. The method includes acquiring data corresponding to the region of reso nance and reconstructing a representation of the specimen based on the data.
Target Audience Researchers, Technicians, and Clinician/Scientists interested in emerging breast ... more Target Audience Researchers, Technicians, and Clinician/Scientists interested in emerging breast imaging methodology, and related applications.
A method includes applying a pulse train to a spin system in a scanner. The pulse train has a plu... more A method includes applying a pulse train to a spin system in a scanner. The pulse train has a plurality of discontinuities in a time domain. The method includes receiving a response from the spin system. The response corresponds to a gated signal. The method includes accessing a correction factor corresponding to the scanner. The method includes calculating a correction to the response based on the correction factor. The method includes generating an output based on the correction.
Introduction: Lung and especially lung parenchyma are difficult to image with MRI 1 . T 2 * times... more Introduction: Lung and especially lung parenchyma are difficult to image with MRI 1 . T 2 * times are in the sub-millisecond range and may require specialized hardware and methods for optimum visualization or quantitative information 1,6-8 . Many lung pathologies such as inflamation (asthma), primary and metastatic neoplasms (cancer) would benefit from robust and high SNR methodologies. For example Kuethe et al. 2 have shown excellent results in rat lung with an optimized radial FID based sequence. We demonstrate here, for the first time, free breathing prospectively gated 1 H SWIFT images of the mouse lung. Lung parenchyma has significant signal and information content while bronchi appear dark. Methods: SWIFT is a novel 3D radial imaging sequence utilizing gapped frequencyswept pulse excitation and nearly simultaneous signal acquisition in the time between the gaps 3,4 . SWIFT utilizes the correlation method 5 which removes phase differences due to the time of excitation and produces FID data (k-space spokes) as if the spokes were simultaneously excited by a short duration pulse. SWIFT has an intrinsically short dead-time, at present hardware-limited to ~2-4 μs. This provides sensitivity to very fast relaxing spins (short T 2 or T 2 * ) similar to BLAST/RUFIS or UTE (Ultrashort TE) sequences 2,6-8 .
Distant dipolar field (DDF)-based nuclear magnetic resonance is an active research area with many... more Distant dipolar field (DDF)-based nuclear magnetic resonance is an active research area with many fundamental properties still not well understood. Already several intriguing applications have developed, like HOMOGENIZED and IDEAL spectroscopy, that allow high resolution spectra to be obtained in inhomogeneous fields, such as in-vivo. The theoretical and experimental research in this thesis concentrates on the fundamental signal properties of
An analytical expression has been developed to describe the effects of T2 relaxation and diffusin... more An analytical expression has been developed to describe the effects of T2 relaxation and diffusing spatially modulated longitudinal spins during the signal build period of an HOMOGENIZED cross peak. Diffusion of the longitudinal spins results in a lengthening of the effective dipolar demagnetization time, delaying the re-phasing of coupled anti-phase states in the quantum picture. In the classical picture the
Purpose To report the results of sweep imaging with Fourier transformation (SWIFT) magnetic reson... more Purpose To report the results of sweep imaging with Fourier transformation (SWIFT) magnetic resonance (MR) imaging for diagnostic breast imaging. Materials and Methods Informed consent was obtained from all participants under one of two institutional review board-approved, HIPAA-compliant protocols. Twelve female patients (age range, 19-54 years; mean age, 41.2 years) and eight normal control subjects (age range, 22-56 years; mean age, 43.2 years) enrolled and completed the study from January 28, 2011, to March 5, 2013. Patients had previous lesions that were Breast Imaging Reporting and Data System 4 and 5 based on mammography and/or ultrasonographic imaging. Contrast-enhanced SWIFT imaging was completed by using a 4-T research MR imaging system. Noncontrast studies were completed in the normal control subjects. One of two sized single-breast SWIFT-compatible transceiver coils was used for nine patients and five controls. Three patients and five control subjects used a SWIFT-compat...
A useful extension to SWIFT (SWeep Imaging with Fourier Transformation) utilizing sidebands of th... more A useful extension to SWIFT (SWeep Imaging with Fourier Transformation) utilizing sidebands of the excitation pulse is introduced. This MRI method, called Multi-Band-SWIFT, achieves much higher bandwidth than standard SWIFT by using multiple segmented excitations (bands) of the field of view. A description of the general idea and variants of the pulse sequence are presented. From simulations and semi-phenomenological theory, estimations of power deposition and signal-to-noise ratio are made. MB-SWIFT and ZTE (zero-TE) sequences are compared based on images of a phantom and human mandible. Multi-Band-SWIFT provides a bridge between SWIFT and ZTE sequences and allows greatly increased excitation and acquisition bandwidths relative to standard SWIFT for the same hardware switching parameters and requires less peak amplitude of the radiofrequency field (or greater flip angle at same peak amplitude) as compared to ZTE. Multi-Band-SWIFT appears to be an attractive extension of SWIFT for certain musculoskeletal and other medical imaging applications, as well as for imaging materials.
A new MRI method is described to acquire a T(2)-weighted image from a single slice in a single sh... more A new MRI method is described to acquire a T(2)-weighted image from a single slice in a single shot. The technique is based on rapid acquisition by sequential excitation and refocusing (RASER). RASER avoids relaxation-related blurring because the magnetization is sequentially refocused in a manner that effectively creates a series of spin echoes with a constant echo time. RASER uses the quadratic phase produced by a frequency-swept chirp pulse to time-encode one dimension of the image. In another implementation the pulse can be used to excite multiple slices with phase-encoding and frequency-encoding in the other two dimensions. The RASER imaging sequence is presented along with single-shot and multislice images, and is compared to conventional spin-echo and echo-planar imaging sequences. A theoretical and empirical analysis of the spatial resolution is presented, and factors in choosing the spatial resolution for different applications are discussed. RASER produces high-quality single-shot images that are expected to be advantageous for a wide range of applications.
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Papers by Curtis A Corum