The Experts below are selected from a list of 18270 Experts worldwide ranked by ideXlab platform
Ponnada A Narayana - One of the best experts on this subject based on the ideXlab platform.
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improved identification of intracortical lesions in multiple sclerosis with phase sensitive Inversion Recovery in combination with fast double Inversion Recovery mr imaging
American Journal of Neuroradiology, 2007Co-Authors: Flavia Nelson, Jerry S Wolinsky, Aziz H Poonawalla, F Huang, Ponnada A NarayanaAbstract:BACKGROUND AND PURPOSE: Accurate detection and classification of purely intracortical lesions in multiple sclerosis (MS) are important in understanding their role in disease progression and impact on the clinical manifestations of the disease. However, detection of these lesions with conventional MR imaging remains a challenge. Although double Inversion Recovery (DIR) has been shown to improve the sensitivity of the detection of cortical lesions, this sequence has low signal-to-noise ratio (SNR), poor delineation of lesion borders, and is prone to image artifacts. We demonstrate that intracortical lesions can be identified and classified with greater confidence by the combination of DIR with phase-sensitive Inversion Recovery (PSIR) images. MATERIALS AND METHODS: A total of 16 subjects with MS were included in this study. DIR, PSIR, and fluid-attenuated Inversion Recovery (FLAIR) images were acquired and inspected by 3 experts, with identification of lesions by consensus. PSIR and DIR images were jointly used to classify lesions as purely intracortical, mixed gray-white matter, and juxtacortical. The difference in the number of lesions detected in each category was compared between combined PSIR and DIR and conventional FLAIR. RESULTS: PSIR consistently allowed a clearer classification and delineation of lesions. Combined PSIR and DIR images showed a 337% improvement in the total number of lesions detected compared with FLAIR alone. Detection of intracortical lesions was improved by 417% compared with FLAIR. Detection of mixed gray-white matter and juxtacortical lesions was improved by 396% and 130%, respectively, compared with FLAIR. CONCLUSION: Reliable detection and classification of intracortical lesions in MS are greatly improved by combined use of PSIR and DIR.
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improved identification of intracortical lesions in multiple sclerosis with phase sensitive Inversion Recovery in combination with fast double Inversion Recovery mr imaging
American Journal of Neuroradiology, 2007Co-Authors: Flavia Nelson, Jerry S Wolinsky, Ping Hou, Aziz H Poonawalla, F Huang, Ponnada A NarayanaAbstract:BACKGROUND AND PURPOSE: Accurate detection and classification of purely intracortical lesions in multiple sclerosis (MS) are important in understanding their role in disease progression and impact on the clinical manifestations of the disease. However, detection of these lesions with conventional MR imaging remains a challenge. Although double Inversion Recovery (DIR) has been shown to improve the sensitivity of the detection of cortical lesions, this sequence has low signal-to-noise ratio (SNR), poor delineation of lesion borders, and is prone to image artifacts. We demonstrate that intracortical lesions can be identified and classified with greater confidence by the combination of DIR with phase-sensitive Inversion Recovery (PSIR) images. MATERIALS AND METHODS: A total of 16 subjects with MS were included in this study. DIR, PSIR, and fluid-attenuated Inversion Recovery (FLAIR) images were acquired and inspected by 3 experts, with identification of lesions by consensus. PSIR and DIR images were jointly used to classify lesions as purely intracortical, mixed gray-white matter, and juxtacortical. The difference in the number of lesions detected in each category was compared between combined PSIR and DIR and conventional FLAIR. RESULTS: PSIR consistently allowed a clearer classification and delineation of lesions. Combined PSIR and DIR images showed a 337% improvement in the total number of lesions detected compared with FLAIR alone. Detection of intracortical lesions was improved by 417% compared with FLAIR. Detection of mixed gray-white matter and juxtacortical lesions was improved by 396% and 130%, respectively, compared with FLAIR. CONCLUSION: Reliable detection and classification of intracortical lesions in MS are greatly improved by combined use of PSIR and DIR.
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phase sensitive t1 Inversion Recovery imaging a time efficient interleaved technique for improved tissue contrast in neuroimaging
American Journal of Neuroradiology, 2005Co-Authors: Khader M Hasan, Clark W Sitton, Jerry S Wolinsky, Ponnada A NarayanaAbstract:BACKGROUND AND PURPOSE: High tissue contrast and short acquisition time are desirable when scanning patients. The purpose of this report is to describe the implementation of a new technique for generating high gray matter (GM) and white matter (WM) contrast in a short scan time, make a quantitative evaluation of the contrast efficiency, and explore its potential applications in neuroimaging. METHOD: A fully interleaved T1-weighted Inversion Recovery (T1IR) sequence with phase-sensitive reconstruction (PS-T1IR) is implemented. This sequence is compared with conventional T1-weighted spin-echo imaging (T1SE) and T1-weighted fluid-attenuated Inversion Recovery (T1FLAIR). The time efficiency and contrast enhancement have been quantitatively analyzed in normal volunteers. The performance of the sequence is evaluated in >30 patients with neurologic disorders. The sensitivity of PS-T1IR relative to T1SE in detecting gadolinium enhancements is also evaluated. RESULTS: PS-T1IR is more time-efficient than T1SE and generates better GM-WM contrast. It results in the best contrast-to-noise ratio (CNR) efficiency (1.16) compared with T1FLAIR (0.73) and T1SE (0.23). For a typical clinical protocol, PS-T1IR takes only 1:30 minutes versus 2:40 minutes for T1SE imaging for the whole brain coverage. Although gadolinium enhancements are detected with comparable sensitivity on both PS-T1IR and T1SE sequences, in certain instances, the latter sequence appears to be more sensitive in demonstrating gadolinium enhancements within WM. CONCLUSION: PS-T1IR has the highest CNR efficiency compared with T1FLAIR and T1SE. It is a very practical technique for neuroradiologic applications.
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phase sensitive t1 Inversion Recovery imaging a time efficient interleaved technique for improved tissue contrast in neuroimaging
American Journal of Neuroradiology, 2005Co-Authors: Ping Hou, Khader M Hasan, Clark W Sitton, Jerry S Wolinsky, Ponnada A NarayanaAbstract:BACKGROUND AND PURPOSE: High tissue contrast and short acquisition time are desirable when scanning patients. The purpose of this report is to describe the implementation of a new technique for generating high gray matter (GM) and white matter (WM) contrast in a short scan time, make a quantitative evaluation of the contrast efficiency, and explore its potential applications in neuroimaging. METHOD: A fully interleaved T1-weighted Inversion Recovery (T1IR) sequence with phase-sensitive reconstruction (PS-T1IR) is implemented. This sequence is compared with conventional T1-weighted spin-echo imaging (T1SE) and T1-weighted fluid-attenuated Inversion Recovery (T1FLAIR). The time efficiency and contrast enhancement have been quantitatively analyzed in normal volunteers. The performance of the sequence is evaluated in >30 patients with neurologic disorders. The sensitivity of PS-T1IR relative to T1SE in detecting gadolinium enhancements is also evaluated. RESULTS: PS-T1IR is more time-efficient than T1SE and generates better GM-WM contrast. It results in the best contrast-to-noise ratio (CNR) efficiency (1.16) compared with T1FLAIR (0.73) and T1SE (0.23). For a typical clinical protocol, PS-T1IR takes only 1:30 minutes versus 2:40 minutes for T1SE imaging for the whole brain coverage. Although gadolinium enhancements are detected with comparable sensitivity on both PS-T1IR and T1SE sequences, in certain instances, the latter sequence appears to be more sensitive in demonstrating gadolinium enhancements within WM. CONCLUSION: PS-T1IR has the highest CNR efficiency compared with T1FLAIR and T1SE. It is a very practical technique for neuroradiologic applications.
G M Bydder - One of the best experts on this subject based on the ideXlab platform.
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t1 measurement of bound water in cortical bone using 3d adiabatic Inversion Recovery ultrashort echo time 3d ir ute cones imaging
Magnetic Resonance in Medicine, 2020Co-Authors: Tan Guo, Saeed Jerban, Hyungseok Jang, Wei Zhao, Eric Y Chang, Min Chen, G M BydderAbstract:PURPOSE We describe the measurement of bound water T1 ( T1BW ) of cortical bone in vitro and in vivo with a 3D adiabatic Inversion Recovery ultrashort echo time (IR-UTE) Cones sequence using a clinical 3T scanner. METHODS A series IR-UTE data from 6 repetition times (TRs) with 5 Inversion times (TIs) at each TR were acquired from 12 human tibial bone specimens, and data from 4 TRs with 5 TIs at each TR were acquired from the tibial midshafts of 8 healthy volunteers. The pore water nulling point was calculated from exponential fitting of the Inversion Recovery curve at each TR. Bone specimens and volunteers were then scanned again with the calculated nulling point at each TR. T1BW was derived through exponential fitting of data from IR-UTE images acquired at different TRs using the calculated pore water nulling point for each TR. RESULTS In vitro pore water nulling TIs were 141.3 ± 11.6, 123.4 ± 8.9, 101.3 ± 6.2, 88.9 ± 5.3, 74.8 ± 4.2, and 59.2 ± 3.9 ms for the 6 TRs of 500, 400, 300, 250, 200, and 150 ms, respectively. In vivo pore water nulling TIs were 132.8 ± 12.8, 110.3 ± 10.0, 80.0 ± 7.2, and 63.9 ± 5.4 ms for the 4 TRs of 400, 300, 200, and 150 ms, respectively. Excellent exponential fitting was achieved for IR-UTE imaging of bound water with pore water nulled at each TR. The mean T1BW was 106.9 ± 6.3 ms in vitro and 112.3 ± 16.4 ms in vivo. CONCLUSION Using the 3D IR-UTE Cones with a variable TR/TI approach, T1BW of cortical bone was calculated after complete nulling of pore water signals.
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ute imaging with simultaneous water and fat signal suppression using a time efficient multispoke Inversion Recovery pulse sequence
Magnetic Resonance in Medicine, 2016Co-Authors: Michael Carl, G M BydderAbstract:Author(s): Carl, Michael; Bydder, Graeme M; Du, Jiang | Abstract: PurposeThe long repetition time and Inversion time with Inversion Recovery preparation ultrashort echo time (UTE) often causes prohibitively long scan times. We present an optimized method for long T2 signal suppression in which several k-space spokes are acquired after each Inversion preparation.Theory and methodsUsing Bloch equations the sequence parameters such as TI and flip angle were optimized to suppress the long T2 water and fat signals and to maximize short T2 contrast. Volunteer imaging was performed on a healthy male volunteer. Inversion Recovery preparation was performed using a Silver-Hoult adiabatic Inversion pulse together with a three-dimensional (3D) UTE (3D Cones) acquisition.ResultsThe theoretical signal curves generally agreed with the experimentally measured region of interest curves. The multispoke Inversion Recovery method showed good muscle and fatty bone marrow suppression, and highlighted short T2 signals such as these from the femoral and tibial cortex.ConclusionInversion Recovery 3D UTE imaging with multiple spoke acquisitions can be used to effectively suppress long T2 signals and highlight short T2 signals within clinical scan times. Theoretical modeling can be used to determine sequence parameters to optimize long T2 signal suppression and maximize short T2 signals. Experimental results on a volunteer confirmed the theoretical predictions. Magn Reson Med 76:577-582, 2016. © 2015 Wiley Periodicals, Inc.
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use of fluid attenuated Inversion Recovery flair pulse sequences in mri of the brain
Journal of Computer Assisted Tomography, 1992Co-Authors: Joseph V Hajnal, I R Young, David J Bryant, Larry Kasuboski, Pradip M Pattany, Beatrice De Coene, Paul D Lewis, J M Pennock, Angela Oatridge, G M BydderAbstract:Fluid attenuated Inversion Recovery pulse sequences with a long echo time (TE) have been used to image the brain in one volunteer and four patients. The long Inversion time used with this sequence suppresses the signal from CSF and the long TE produces very heavy T2 weighting. The marked reduction in flow artefact from CSF and the high T2 weighting enabled anatomical detail to be seen within the brain stem and produced high lesion contrast in areas close to CSF. Lesions were demonstrated with greater conspicuity than with conventional T2-weighted sequences in patients with cerebral infarction, low grade astrocytoma, and diplegia.
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mr of the brain using fluid attenuated Inversion Recovery flair pulse sequences
American Journal of Neuroradiology, 1992Co-Authors: Beatrice De Coene, I R Young, Joseph V Hajnal, J M Pennock, Angela Oatridge, Peter D Gatehouse, D B Longmore, Susan J White, G M BydderAbstract:PURPOSE Results from conventional T2-weighted spin-echo sequences were compared with those obtained using fluid attenuated Inversion Recovery (FLAIR) pulse sequences in order to assess their relative merits in detecting disease. METHODS Forty adult patients with suspected disease of the brain were examined with spin-echo sequences (TE = 20 and TE = 80), and results were compared with FLAIR sequences of several types with Inversion times of 1800-3000 msec and echo times of 130-240 msec. Scans were assessed by two radiologists for lesion number, conspicuity, and extent. RESULTS A total of 48 lesions or groups of lesions were recognized with both sequences. In 22 instances, more lesions were seen with FLAIR sequences, and, in the remaining 26, equal numbers were seen. In 42 lesions, conspicuity was better with FLAIR sequences, equal in five and worse in one cystic lesion. Lesion extent was better assessed in 28 of the 48 cases with FLAIR sequences and equally well seen in the remainder. CONCLUSION By virtue of their long echo time and relative freedom from cerebrospinal fluid artifact FLAIR sequences provide high sensitivity to a wide range of disease. The basic sequence is easy to implement but is relatively time consuming.
Anthony H Aletras - One of the best experts on this subject based on the ideXlab platform.
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new automatic algorithm for segmentation of myocardial scar in both Inversion Recovery and phase sensitive Inversion Recovery late gadolinium enhancement validation against ttc and in multi center multi vendor patient data
Journal of Cardiovascular Magnetic Resonance, 2016Co-Authors: Jane Tufvesson, Robert Jablonowski, Henrik Engblom, Marcus Carlsson, Anthony H Aletras, Pavel Hoffmann, Alexis Jacquier, Frank Kober, Bernhard MetzlerAbstract:New automatic algorithm for segmentation of myocardial scar in both Inversion Recovery and phase sensitive Inversion Recovery late gadolinium enhancement: validation against TTC and in multi-center, multi-vendor patient data Jane Tufvesson, Robert Jablonowski, Henrik Engblom, Marcus Carlsson, Anthony H Aletras, Pavel Hoffmann, Alexis Jacquier, Frank Kober, Bernhard Metzler, David Erlinge, Dan Atar, Hakan Arheden, Einar Heiberg
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air spamm alternative Inversion Recovery spatial modulation of magnetization for myocardial tagging
Journal of Magnetic Resonance, 2004Co-Authors: Anthony H Aletras, Raisa Z Freidlin, Gil Navon, Andrew E AraiAbstract:Abstract Alternate Inversion Recovery spatial modulation of magnetization (AIR-SPAMM) can be used either for doubling the number of tags for a given tagging encoding gradient strength or for improving tagging contrast ratio. AIR-SPAMM requires only a single acquisition and utilizes Inversion pulses spaced throughout the gradient recalled echo (GRE) cine acquisition to “lock” the recovering magnetization at a desired level. The theory of AIR-SPAMM is presented along with simulations and results from phantoms. AIR-SPAMM can be used either for imaging systole as demonstrated by initial in vivo results or potentially for imaging the entire cardiac cycle in a slice-interleaved manner.
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phase sensitive Inversion Recovery for detecting myocardial infarction using gadolinium delayed hyperenhancement
Magnetic Resonance in Medicine, 2002Co-Authors: Peter Kellman, Andrew E Arai, Elliot R Mcveigh, Anthony H AletrasAbstract:After administration of gadolinium, infarcted myocardium exhibits delayed hyperenhancement and can be imaged using an Inversion Recovery (IR) sequence. The performance of such a method when using magnitude-reconstructed images is highly sensitive to the Inversion Recovery time (TI) selected. Using phase-sensitive reconstruction, it is possible to use a nominal value of TI, eliminate several breath-holds otherwise needed to find the precise null time for normal myocardium, and achieve a consistent contrast. Phase-sensitive detection is used to remove the background phase while preserving the sign of the desired magnetization during IR. Experimental results are presented which demonstrate the benefits of both phase-sensitive IR image reconstruction and surface coil intensity normalization for detecting myocardial infarction (MI). The phase-sensitive reconstruction method reduces the variation in apparent infarct size that is observed in the magnitude images as TI is changed. Phase-sensitive detection also has the advantage of decreasing the sensitivity to changes in tissue T1 with increasing delay from contrast agent injection. Magn Reson Med 47: 372‐383, 2002. Published 2002 Wiley-Liss, Inc. †
Seonggi Kim - One of the best experts on this subject based on the ideXlab platform.
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perfusion imaging by a flow sensitive alternating Inversion Recovery fair technique application to functional brain imaging
Magnetic Resonance in Medicine, 1997Co-Authors: Seonggi Kim, Nikolaos V TsekosAbstract:Perfusion is a crucial physiological parameter for tissue function. To obtain perfusion-weighted images and consequently to measure cerebral blood flow (CBF), a newly developed flow-sensitive alternating Inversion Recovery (FAIR) technique was used. Dependency of FAIR signal on Inversion times (TI) was examined; signal is predominantly located in large vessels at short TI, whereas it is diffused into gray matter areas at longer TI. CBF of gray matter areas in the human brain is 71 +/- 15 SD ml/100 g/min (n = 6). In fMRI studies, micro- and macrovessel inflow contributions can be obtained by adjusting TIs. Signal changes in large vessel areas including the scalp were seen during finger opposition at a TI of 0.4 s; however, these were not observed at a longer TI of 1.4 s. To compare with commonly used BOLD and slice selective Inversion Recovery techniques, FAIR and BOLD images were acquired at the same time during unilateral finger opposition. Generally, activation sites determined by three techniques are consistent. However, activation of some areas can be detected only by FAIR, not by BOLD, suggesting that the oxygen consumption increase couples with the CBF change completely. Relative and absolute CBF changes in the contralateral motor cortex are 53 +/- 17% SD (n = 9) and 27 +/- 11 SD ml/100 g/min (n = 9), respectively.
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quantification of relative cerebral blood flow change by flow sensitive alternating Inversion Recovery fair technique application to functional mapping
Magnetic Resonance in Medicine, 1995Co-Authors: Seonggi KimAbstract:Relative cerebral blood flow changes can be measured by a novel simple blood flow measurement technique with endogenous water protons as a tracer based on flow-sensitive alternating Inversion Recovery (FAIR). Two Inversion Recovery (IR) images are acquired by interleaving slice-selective Inversion and nonselective Inversion. During the Inversion delay time after slice-selective Inversion, fully magnetized blood spins move into the imaging slice and exchange with tissue water. The signal enhancement (FAIR image) measured by the signal difference between two images is directly related to blood flow. For functional MR imaging studies, two IR images are alternatively and repeatedly acquired during control and task periods. Relative signal changes in the FAIR images during the task periods represent the relative regional cerebral blood flow changes. The FAIR technique has been successfully applied to functional brain mapping studies in humans during finger opposition movements. The technique is capable of generating microvascular-based functional maps.
Jerry S Wolinsky - One of the best experts on this subject based on the ideXlab platform.
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improved identification of intracortical lesions in multiple sclerosis with phase sensitive Inversion Recovery in combination with fast double Inversion Recovery mr imaging
American Journal of Neuroradiology, 2007Co-Authors: Flavia Nelson, Jerry S Wolinsky, Aziz H Poonawalla, F Huang, Ponnada A NarayanaAbstract:BACKGROUND AND PURPOSE: Accurate detection and classification of purely intracortical lesions in multiple sclerosis (MS) are important in understanding their role in disease progression and impact on the clinical manifestations of the disease. However, detection of these lesions with conventional MR imaging remains a challenge. Although double Inversion Recovery (DIR) has been shown to improve the sensitivity of the detection of cortical lesions, this sequence has low signal-to-noise ratio (SNR), poor delineation of lesion borders, and is prone to image artifacts. We demonstrate that intracortical lesions can be identified and classified with greater confidence by the combination of DIR with phase-sensitive Inversion Recovery (PSIR) images. MATERIALS AND METHODS: A total of 16 subjects with MS were included in this study. DIR, PSIR, and fluid-attenuated Inversion Recovery (FLAIR) images were acquired and inspected by 3 experts, with identification of lesions by consensus. PSIR and DIR images were jointly used to classify lesions as purely intracortical, mixed gray-white matter, and juxtacortical. The difference in the number of lesions detected in each category was compared between combined PSIR and DIR and conventional FLAIR. RESULTS: PSIR consistently allowed a clearer classification and delineation of lesions. Combined PSIR and DIR images showed a 337% improvement in the total number of lesions detected compared with FLAIR alone. Detection of intracortical lesions was improved by 417% compared with FLAIR. Detection of mixed gray-white matter and juxtacortical lesions was improved by 396% and 130%, respectively, compared with FLAIR. CONCLUSION: Reliable detection and classification of intracortical lesions in MS are greatly improved by combined use of PSIR and DIR.
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improved identification of intracortical lesions in multiple sclerosis with phase sensitive Inversion Recovery in combination with fast double Inversion Recovery mr imaging
American Journal of Neuroradiology, 2007Co-Authors: Flavia Nelson, Jerry S Wolinsky, Ping Hou, Aziz H Poonawalla, F Huang, Ponnada A NarayanaAbstract:BACKGROUND AND PURPOSE: Accurate detection and classification of purely intracortical lesions in multiple sclerosis (MS) are important in understanding their role in disease progression and impact on the clinical manifestations of the disease. However, detection of these lesions with conventional MR imaging remains a challenge. Although double Inversion Recovery (DIR) has been shown to improve the sensitivity of the detection of cortical lesions, this sequence has low signal-to-noise ratio (SNR), poor delineation of lesion borders, and is prone to image artifacts. We demonstrate that intracortical lesions can be identified and classified with greater confidence by the combination of DIR with phase-sensitive Inversion Recovery (PSIR) images. MATERIALS AND METHODS: A total of 16 subjects with MS were included in this study. DIR, PSIR, and fluid-attenuated Inversion Recovery (FLAIR) images were acquired and inspected by 3 experts, with identification of lesions by consensus. PSIR and DIR images were jointly used to classify lesions as purely intracortical, mixed gray-white matter, and juxtacortical. The difference in the number of lesions detected in each category was compared between combined PSIR and DIR and conventional FLAIR. RESULTS: PSIR consistently allowed a clearer classification and delineation of lesions. Combined PSIR and DIR images showed a 337% improvement in the total number of lesions detected compared with FLAIR alone. Detection of intracortical lesions was improved by 417% compared with FLAIR. Detection of mixed gray-white matter and juxtacortical lesions was improved by 396% and 130%, respectively, compared with FLAIR. CONCLUSION: Reliable detection and classification of intracortical lesions in MS are greatly improved by combined use of PSIR and DIR.
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phase sensitive t1 Inversion Recovery imaging a time efficient interleaved technique for improved tissue contrast in neuroimaging
American Journal of Neuroradiology, 2005Co-Authors: Khader M Hasan, Clark W Sitton, Jerry S Wolinsky, Ponnada A NarayanaAbstract:BACKGROUND AND PURPOSE: High tissue contrast and short acquisition time are desirable when scanning patients. The purpose of this report is to describe the implementation of a new technique for generating high gray matter (GM) and white matter (WM) contrast in a short scan time, make a quantitative evaluation of the contrast efficiency, and explore its potential applications in neuroimaging. METHOD: A fully interleaved T1-weighted Inversion Recovery (T1IR) sequence with phase-sensitive reconstruction (PS-T1IR) is implemented. This sequence is compared with conventional T1-weighted spin-echo imaging (T1SE) and T1-weighted fluid-attenuated Inversion Recovery (T1FLAIR). The time efficiency and contrast enhancement have been quantitatively analyzed in normal volunteers. The performance of the sequence is evaluated in >30 patients with neurologic disorders. The sensitivity of PS-T1IR relative to T1SE in detecting gadolinium enhancements is also evaluated. RESULTS: PS-T1IR is more time-efficient than T1SE and generates better GM-WM contrast. It results in the best contrast-to-noise ratio (CNR) efficiency (1.16) compared with T1FLAIR (0.73) and T1SE (0.23). For a typical clinical protocol, PS-T1IR takes only 1:30 minutes versus 2:40 minutes for T1SE imaging for the whole brain coverage. Although gadolinium enhancements are detected with comparable sensitivity on both PS-T1IR and T1SE sequences, in certain instances, the latter sequence appears to be more sensitive in demonstrating gadolinium enhancements within WM. CONCLUSION: PS-T1IR has the highest CNR efficiency compared with T1FLAIR and T1SE. It is a very practical technique for neuroradiologic applications.
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phase sensitive t1 Inversion Recovery imaging a time efficient interleaved technique for improved tissue contrast in neuroimaging
American Journal of Neuroradiology, 2005Co-Authors: Ping Hou, Khader M Hasan, Clark W Sitton, Jerry S Wolinsky, Ponnada A NarayanaAbstract:BACKGROUND AND PURPOSE: High tissue contrast and short acquisition time are desirable when scanning patients. The purpose of this report is to describe the implementation of a new technique for generating high gray matter (GM) and white matter (WM) contrast in a short scan time, make a quantitative evaluation of the contrast efficiency, and explore its potential applications in neuroimaging. METHOD: A fully interleaved T1-weighted Inversion Recovery (T1IR) sequence with phase-sensitive reconstruction (PS-T1IR) is implemented. This sequence is compared with conventional T1-weighted spin-echo imaging (T1SE) and T1-weighted fluid-attenuated Inversion Recovery (T1FLAIR). The time efficiency and contrast enhancement have been quantitatively analyzed in normal volunteers. The performance of the sequence is evaluated in >30 patients with neurologic disorders. The sensitivity of PS-T1IR relative to T1SE in detecting gadolinium enhancements is also evaluated. RESULTS: PS-T1IR is more time-efficient than T1SE and generates better GM-WM contrast. It results in the best contrast-to-noise ratio (CNR) efficiency (1.16) compared with T1FLAIR (0.73) and T1SE (0.23). For a typical clinical protocol, PS-T1IR takes only 1:30 minutes versus 2:40 minutes for T1SE imaging for the whole brain coverage. Although gadolinium enhancements are detected with comparable sensitivity on both PS-T1IR and T1SE sequences, in certain instances, the latter sequence appears to be more sensitive in demonstrating gadolinium enhancements within WM. CONCLUSION: PS-T1IR has the highest CNR efficiency compared with T1FLAIR and T1SE. It is a very practical technique for neuroradiologic applications.
