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Han SH, Cho FH, Song YK, Paulsen J, Song YQ, Kim YR, Kim JK, Cho G, Cho H. Ultrafast 3D spin-echo acquisition improves Gadolinium-enhanced MRI signal contrast enhancement. Sci Rep 2014; 4:5061. [PMID: 24863102 PMCID: PMC4034007 DOI: 10.1038/srep05061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 05/07/2014] [Indexed: 11/27/2022] Open
Abstract
Long scan times of 3D volumetric MR acquisitions usually necessitate ultrafast in vivo gradient-echo acquisitions, which are intrinsically susceptible to magnetic field inhomogeneities. This is especially problematic for contrast-enhanced (CE)-MRI applications, where non-negligible T2* effect of contrast agent deteriorates the positive signal contrast and limits the available range of MR acquisition parameters and injection doses. To overcome these shortcomings without degrading temporal resolution, ultrafast spin-echo acquisitions were implemented. Specifically, a multiplicative acceleration factor from multiple spin echoes (×32) and compressed sensing (CS) sampling (×8) allowed highly-accelerated 3D Multiple-Modulation-Multiple-Echo (MMME) acquisition. At the same time, the CE-MRI of kidney with Gd-DOTA showed significantly improved signal enhancement for CS-MMME acquisitions (×7) over that of corresponding FLASH acquisitions (×2). Increased positive contrast enhancement and highly accelerated acquisition of extended volume with reduced RF irradiations will be beneficial for oncological and nephrological applications, in which the accurate in vivo 3D quantification of contrast agent concentration is necessary with high temporal resolution.
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Affiliation(s)
- S H Han
- Department of Biomedical Engineering, UNIST, Ulsan, South Korea
| | - F H Cho
- Department of Biomedical Engineering, UNIST, Ulsan, South Korea
| | - Y K Song
- Department of Biomedical Engineering, UNIST, Ulsan, South Korea
| | - J Paulsen
- Schlumberger Doll Research Center, Cambridge, MA, USA
| | - Y Q Song
- Schlumberger Doll Research Center, Cambridge, MA, USA
| | - Y R Kim
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
| | - J K Kim
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - G Cho
- Korea Basic Science Institute, Ochang, South Korea
| | - H Cho
- Department of Biomedical Engineering, UNIST, Ulsan, South Korea
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Jin G, An N, Jacobs MA, Li K. The role of parallel diffusion-weighted imaging and apparent diffusion coefficient (ADC) map values for evaluating breast lesions: preliminary results. Acad Radiol 2010; 17:456-63. [PMID: 20207316 DOI: 10.1016/j.acra.2009.12.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 11/30/2009] [Accepted: 12/04/2009] [Indexed: 11/15/2022]
Abstract
RATIONALE AND OBJECTIVES To evaluate the feasibility of using diffusion-weighted imaging (DWI) with an array spatial sensitivity encoding technique (ASSET) and apparent diffusion coefficient (ADC) map values with different b values to distinguish benign and malignant breast lesions. MATERIALS AND METHODS Fifty-six female patients with 60 histologically proven breast lesions and 20 healthy volunteers underwent magnetic resonance imaging. A subset of normal volunteers (n = 7) and patients (n = 16) underwent both conventional DWI and ASSET-DWI, and the image quality between the two methods was compared. Finally, ASSET-DWI with b = 0, 600 s/mm(2), and b = 0, 1000 s/mm(2), were compared for their ability to distinguish benign and malignant breast lesions. RESULTS The ASSET-DWI method had less distortion, fewer artifacts, and a lower acquisition time than other methods. No significant difference (P > .05) was detected in ADC map values between ASSET-DWI and conventional DWI. For ASSET-DWI, the sensitivity of ADC values for malignant lesions with a threshold of less than 1.44 x 10(-3) mm(2)/s (b = 600 s/mm(2)) and 1.18 x 10(-3) mm(2)/s (b = 1000 s/mm(2)) was 80% and 77.5%, respectively. The specificity of both groups was 95%. CONCLUSION ASSET-DWI evaluation of breast tissue offers decreased distortion, susceptibility to artifacts, and acquisition time relative to other methods. The use of ASSET-DWI is feasible with b values ranging from 600 to 1000 s/mm(2) and provides increased specificity compared to other techniques. Thus, the ADC value of a breast lesion can be used to further characterize malignant lesions from benign ones.
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Affiliation(s)
- Guangwei Jin
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China 100053
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Jiang ZX, Peng WJ, Li WT, Tang F, Liu SY, Qu XD, Wang JH, Lu HF. Effect of b value on monitoring therapeutic response by diffusion-weighted imaging. World J Gastroenterol 2008; 14:5893-9. [PMID: 18855990 PMCID: PMC2751901 DOI: 10.3748/wjg.14.5893] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To explore the diffusion gradient b-factor that optimizes both apparent diffusion coefficient (ADC) measurement and contrast-to-noise (CNR) for assessing tumor response to transarterial chemoembolization (TACE) in a rabbit model.
METHODS: Twelve New Zealand white rabbits bearing VX2 tumors in the liver were treated with TACE. Diffusion-weighted imaging (DWI) with various b values was performed using the same protocol before and 3 d after treatment with TACE. ADC values and CNR of each tumor pre- and post-treatment with different b factors were analyzed. Correlation between ADC values and extent of necrosis in histological specimens was analyzed by a Pearson’s correlation test.
RESULTS: The quality of diffusion-weighted images diminished as the b value increased. A substantial decrease in the mean lesion-to-liver CNR was observed on both pre- and post-treatment DW images, the largest difference in CNR pre- and post-treatment was manifested at a b value of 1000 s/mm2 (P = 0.036 ). The effect of therapy on diffusion early after treatment was shown by a significant increase in ADCs (P = 0.007), especially with large b factors (≥ 600 s/mm2). The mean percentage of necrotic cells present within the tumor was 76.3%-97.5%. A significant positive correlation was found between ADC values and the extent of necrosis with all b values except for b200, a higher relative coefficient between ADC values and percentage of necrosis was found on DWI with b1000 and b2000 (P = 0.002 and 0.006, respectively).
CONCLUSION: An increasing b value of up to 600 s/mm2 would increase ADC contrast pre- and post-treatment, but decrease image quality. Taking into account both CNR and ADC measurement, diffusion-weighted imaging obtained with a b value of 1000 s/mm2 is recommended for monitoring early hepatic tumor response to TACE.
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Thoeny HC, De Keyzer F. Extracranial applications of diffusion-weighted magnetic resonance imaging. Eur Radiol 2007; 17:1385-93. [PMID: 17206421 DOI: 10.1007/s00330-006-0547-0] [Citation(s) in RCA: 224] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Revised: 11/03/2006] [Accepted: 11/28/2006] [Indexed: 12/11/2022]
Abstract
Diffusion-weighted MRI has become more and more popular in the last couple of years. It is already an accepted diagnostic tool for patients with acute stroke, but is more difficult to use for extracranial applications due to technical challenges mostly related to motion sensitivity and susceptibility variations (e.g., respiration and air-tissue boundaries). However, thanks to the newer technical developments, applications of body DW-MRI are starting to emerge. In this review, we aim to provide an overview of the current status of the published data on DW-MRI in extracranial applications. A short introduction to the physical background of this promising technique is provided, followed by the current status, subdivided into three main topics, the functional evaluation, tissue characterization and therapy monitoring.
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Affiliation(s)
- Harriet C Thoeny
- Department of Radiology, Neuroradiology and Nuclear Medicine, University Hospital of Bern, Inselspital, Freiburgstrasse 10, CH-3010 Bern, Switzerland.
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Schmierer K, Wheeler-Kingshott CAM, Boulby PA, Scaravilli F, Altmann DR, Barker GJ, Tofts PS, Miller DH. Diffusion tensor imaging of post mortem multiple sclerosis brain. Neuroimage 2006; 35:467-77. [PMID: 17258908 PMCID: PMC1892244 DOI: 10.1016/j.neuroimage.2006.12.010] [Citation(s) in RCA: 296] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 12/02/2006] [Accepted: 12/05/2006] [Indexed: 01/21/2023] Open
Abstract
Magnetic resonance imaging (MRI) is being used to probe the central nervous system (CNS) of patients with multiple sclerosis (MS), a chronic demyelinating disease. Conventional T2-weighted MRI (cMRI) largely fails to predict the degree of patients' disability. This shortcoming may be due to poor specificity of cMRI for clinically relevant pathology. Diffusion tensor imaging (DTI) has shown promise to be more specific for MS pathology. In this study we investigated the association between histological indices of myelin content, axonal count and gliosis, and two measures of DTI (mean diffusivity [MD] and fractional anisotropy [FA]), in unfixed post mortem MS brain using a 1.5-T MR system. Both MD and FA were significantly lower in post mortem MS brain compared to published data acquired in vivo. However, the differences of MD and FA described in vivo between white matter lesions (WMLs) and normal-appearing white matter (NAWM) were retained in this study of post mortem brain: average MD in WMLs was 0.35 × 10− 3 mm2/s (SD, 0.09) versus 0.22 (0.04) in NAWM; FA was 0.22 (0.06) in WMLs versus 0.38 (0.13) in NAWM. Correlations were detected between myelin content (Trmyelin) and (i) FA (r = − 0.79, p < 0.001), (ii) MD (r = 0.68, p < 0.001), and (iii) axonal count (r = − 0.81, p < 0.001). Multiple regression suggested that these correlations largely explain the apparent association of axonal count with (i) FA (r = 0.70, p < 0.001) and (ii) MD (r = − 0.66, p < 0.001). In conclusion, this study suggests that FA and MD are affected by myelin content and – to a lesser degree – axonal count in post mortem MS brain.
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Affiliation(s)
- Klaus Schmierer
- Institute of Neurology, University College London, NMR Research Unit, Box 117, Queen Square, London WC1N 3BG, UK.
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Weber DL, Jakob PM. Diffusion-weighted imaging with a rapid repeated hole-burning sequence. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 182:152-9. [PMID: 16837222 DOI: 10.1016/j.jmr.2006.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 05/30/2006] [Accepted: 06/05/2006] [Indexed: 05/10/2023]
Abstract
Diffusion-weighted imaging in the presence of extremely short T2-relaxation time is generally not feasible with a standard PGSE experiment due to the superposed signal decays caused primarily by T2-relaxation and secondarily by diffusion. Here, we present a new method for diffusion-weighted imaging achieved by a nearly T2-independent pre-experiment where a DANTE-pulse train is repeated rapidly.
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Affiliation(s)
- Daniel L Weber
- Department of Experimental Physics 5, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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Abstract
Despite the essential role morphological imaging plays in the management of patients with malignancy, anatomical techniques are limited in their ability to report on tumour biology and behaviour. It has therefore been necessary to develop imaging techniques that integrate form and function to probe the micro and molecular environments of cancers. The role of clinical functional and molecular magnetic resonance imaging is discussed with an emphasis on pelvic malignancy. It is argued that the radiological sciences need to take a lead in translating molecular and functional imaging techniques into man. Imaging in support of drug development is suggested as a focus for that development.
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Thoeny HC, De Keyzer F, Chen F, Ni Y, Landuyt W, Verbeken EK, Bosmans H, Marchal G, Hermans R. Diffusion-weighted MR imaging in monitoring the effect of a vascular targeting agent on rhabdomyosarcoma in rats. Radiology 2005; 234:756-64. [PMID: 15734932 DOI: 10.1148/radiol.2343031721] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE To evaluate diffusion-weighted magnetic resonance (MR) imaging for monitoring tumor response in rats after administration of combretastatin A4 phosphate. MATERIALS AND METHODS Study protocol was approved by local ethical committee for animal care and use. Rhabdomyosarcomas implanted subcutaneously in both flanks of 17 rats were evaluated with 1.5-T MR unit by using four-channel wrist coil. Transverse T2-weighted fast spin-echo sequences, T1-weighted spin-echo sequences before and after gadodiamide administration, and transverse echo-planar diffusion-weighted MR examinations were performed before, 1 and 6 hours, and 2 and 9 days after intraperitoneal injection of vascular targeting agent (combretastatin A4 phosphate, 25 mg/kg). Apparent diffusion coefficient (ADC) was automatically calculated from diffusion-weighted MR imaging findings. These findings were compared with histopathologic results at each time point. For statistical analysis, paired Student t tests with Bonferroni correction for multiple testing were used. RESULTS T1-weighted images before combretastatin administration showed enhancement of solid tumor tissue but not of central necrosis. At 1 and 6 hours after combretastatin injection, enhancement of solid tissue disappeared almost completely, with exception of small peripheral rim. At 2 and 9 days after combretastatin injection, enhancement progressively reappeared in tumor periphery. ADC, however, showed decrease early after combretastatin injection ([1.26 +/- 0.16]x 10(-3) mm2/sec before, [1.18 +/- 0.17]x 10(-3) mm2/sec 1 hour after [P=.0005] and [1.08 +/- 0.14]x 10(-3) mm(2)/sec 6 hours after [P=.0007] combretastatin A4 phosphate injection), histologically corresponding to vessel congestion and vascular shutdown in periphery but no necrosis. An increase of ADC ([1.79 +/- 0.13]x 10(-3) mm2/sec) (P <.0001) 2 days after combretastatin A4 phosphate injection was paralleled by progressive histologic necrosis. A significant (P <.0001) decrease in ADC 9 days after treatment ([1.41 +/- 0.15]x 10(-3) mm2/sec) corresponded to tumor regrowth. CONCLUSION In addition to basic relaxation-weighted MR imaging and postgadolinium T1-weighted MR imaging to enable prompt detection of vascular shutdown, diffusion-weighted MR imaging was used to discriminate between nonperfused but viable and necrotic tumor tissues for early monitoring of therapeutic effects of vascular targeting agent.
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Affiliation(s)
- Harriet C Thoeny
- Department of Radiology, University Hospitals Leuven, Herestraat 49, B-3000 Leuven, Belgium
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Dzik-Jurasz A. The development and application of functional nuclear magnetic resonance toin vivotherapeutic anticancer research. Br J Radiol 2004; 77:296-307. [PMID: 15107319 DOI: 10.1259/bjr/95415645] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A little over 30 years ago, Sir Godfrey Hounsfield and his colleagues revolutionized medical imaging by developing CT scanning. In recent years a combination of improved technology and a deeper understanding of tumour biology have led to the development of imaging based strategies aimed at interrogating tissue structure and function. The prospects of this new technology include the prediction of tumour response and the non-invasive study of conventionally inaccessible yet important pharmacological compartments. This article explores how functional nuclear MRI and spectroscopy have been used in predicting response to anticancer therapy in rectal cancers and to assess the biliary excretion of chemotherapeutics.
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Affiliation(s)
- A Dzik-Jurasz
- The Cancer Research UK Clinical Magnetic Resonance Research Group, Institute of Cancer Research and the Royal Marsden NHS Trust, Sutton, Surrey SM2 5PT, UK
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Thoeny HC, De Keyzer F, Boesch C, Hermans R. Diffusion-weighted imaging of the parotid gland: Influence of the choice ofb-values on the apparent diffusion coefficient value. J Magn Reson Imaging 2004; 20:786-90. [PMID: 15503336 DOI: 10.1002/jmri.20196] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To determine how the ADC value of parotid glands is influenced by the choice of b-values. MATERIALS AND METHODS In eight healthy volunteers, diffusion-weighted echo-planar imaging (DW-EPI) was performed on a 1.5 T system, with b-values (in seconds/mm2) of 0, 50, 100, 150, 200, 250, 300, 500, 750, and 1000. ADC values were calculated by two alternative methods (exponential vs. logarithmic fit) from five different sets of b-values: (A) all b-values; (B) b=0, 50, and 100; (C) b=0 and 750; (D) b=0, 500, and 1000; and (E) b=500, 750, and 1000. RESULTS The mean ADC values for the different settings were (in 10(-3) mm2/second, exponential fit): (A) 0.732+/-0.019, (B) 2.074+/-0.084, (C) 0.947+/-0.020, (D) 0.890+/-0.023, and (E) 0.581+/-0.021. ADC values were significantly (P <0.001) different for all pairwise comparisons of settings (A-E) of b-values, except for A vs. D (P=0.172) and C vs. D (P=0.380). The ADC(B) was significantly higher than ADC(C) or ADC(D), which was significantly higher than ADC(E). ADC values from exponential vs. logarithmic fit (P=0.542), as well as left vs. right parotid gland (P=0.962), were indistinguishable. CONCLUSION The ADC values calculated from low b-value settings were significantly higher than those calculated from high b-value settings. These results suggest that not only true diffusion but also perfusion and saliva flow may contribute to the ADC.
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Affiliation(s)
- Harriet C Thoeny
- Department of Radiology, University Hospitals Leuven, Leuven, Belgium.
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Dzik-Jurasz A, Domenig C, George M, Wolber J, Padhani A, Brown G, Doran S. Diffusion MRI for prediction of response of rectal cancer to chemoradiation. Lancet 2002; 360:307-8. [PMID: 12147376 DOI: 10.1016/s0140-6736(02)09520-x] [Citation(s) in RCA: 403] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Prediction of tumour response before onset of treatment could have considerable clinical benefit. Since the apparent diffusion coefficient (ADC) of a tumour's water content can show the extent of necrosis, we looked for a possible correlation of ADC with response to treatment. We measured mean tumour water ADC before and after chemotherapy and chemoradiation in 14 patients with locally advanced rectal cancer, with a quantitative magnetic resonance diffusion imaging sequence. We found a strong negative correlation between mean pretreatment tumour water ADC and percentage size change of tumours after chemotherapy (r=-0.67, p=0.01) and chemoradiation (r=-0.83, p=0.001). Persistence of low ADC in responders after chemotherapy could represent loss of a non-viable fraction of the treated tumour.
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Affiliation(s)
- Andrzej Dzik-Jurasz
- UK Cancer Research Clinical Magnetic Resonance Research Group, Institute of Cancer Research, Royal Marsden NHS Trust, Downs Road, Sutton SM2 5PT, UK.
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