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Jiang Z, Sun W, Xu D, Mei H, Yuan J, Song X, Ma C, Xu H. The feasibility of half-dose contrast-enhanced scanning of brain tumours at 5.0 T: a preliminary study. BMC Med Imaging 2024; 24:88. [PMID: 38615005 PMCID: PMC11016225 DOI: 10.1186/s12880-024-01270-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 04/05/2024] [Indexed: 04/15/2024] Open
Abstract
PURPOSE This study investigated and compared the effects of Gd enhancement on brain tumours with a half-dose of contrast medium at 5.0 T and with a full dose at 3.0 T. METHODS Twelve subjects diagnosed with brain tumours were included in this study and underwent MRI after contrast agent injection at 3.0 T (full dose) or 5.0 T (half dose) with a 3D T1-weighted gradient echo sequence. The postcontrast images were compared by two independent neuroradiologists in terms of the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and subjective image quality score on a ten-point Likert scale. Quantitative indices and subjective quality ratings were compared with paired Student's t tests, and interreader agreement was assessed with the intraclass correlation coefficient (ICC). RESULTS A total of 16 enhanced tumour lesions were detected. The SNR was significantly greater at 5.0 T than at 3.0 T in grey matter, white matter and enhanced lesions (p < 0.001). The CNR was also significantly greater at 5.0 T than at 3.0 T for grey matter/tumour lesions, white matter/tumour lesions, and grey matter/white matter (p < 0.001). Subjective evaluation revealed that the internal structure and outline of the tumour lesions were more clearly displayed with a half-dose at 5.0 T (Likert scale 8.1 ± 0.3 at 3.0 T, 8.9 ± 0.3 at 5.0 T, p < 0.001), and the effects of enhancement in the lesions were comparable to those with a full dose at 3.0 T (7.8 ± 0.3 at 3.0 T, 8.7 ± 0.4 at 5.0 T, p < 0.001). All subjective scores were good to excellent at both 5.0 T and 3.0 T. CONCLUSION Both quantitative and subjective evaluation parameters suggested that half-dose enhanced scanning via 5.0 T MRI might be feasible for meeting clinical diagnostic requirements, as the image quality remains optimal. Enhanced scanning at 5.0 T with a half-dose of contrast agents might benefit patients with conditions that require less intravenous contrast agent, such as renal dysfunction.
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Affiliation(s)
- Zhiyong Jiang
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan, China
- Medical Imaging Department, Shenzhen Ban'an Traditional Chinese Medicine Hospital Group, Shenzhen, China
| | - Wenbo Sun
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Dan Xu
- Department of Nuclear Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Hao Mei
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | | | - Xiaopeng Song
- United Imaging Healthcare, Shanghai, China
- Wuhan Zhongke Industrial Research Institute, Wuhan, Hubei, China
| | - Chao Ma
- Department of Neurosurgery, Zhongnan Hospital, Wuhan, China.
| | - Haibo Xu
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan, China.
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Comparison of the Relaxivities of Macrocyclic Gadolinium-Based Contrast Agents in Human Plasma at 1.5, 3, and 7 T, and Blood at 3 T. Invest Radiol 2020; 54:559-564. [PMID: 31124800 DOI: 10.1097/rli.0000000000000577] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PURPOSE The relaxivities of 3 macrocyclic gadolinium-based contrast agents (GBCAs) were determined in human plasma and blood under standardized and clinically relevant laboratory conditions. METHODS The T1 relaxivity, r1, was determined in human plasma at 1.5, 3, and 7 T, and in human blood at 3 T at 37°C in phantoms containing 4 different concentrations of the macrocyclic GBCAs gadobutrol, gadoteridol, and gadoterate. An inversion recovery turbo spin echo sequence was used to generate images with several inversion times. The T1-times were obtained by fitting the signal intensities to the signal equation. r1 was obtained by a 1/y-weighted regression of the T1-rates over the concentration of the GBCAs. RESULTS For gadobutrol, the obtained r1 [L/(mmol·s)] in human plasma at 1.5 T, 3 T, and 7 T, and in human blood at 3 T was 4.78 ± 0.12, 4.97 ± 0.59, 3.83 ± 0.24, and 3.47 ± 0.16. For gadoteridol, r1 was 3.80 ± 0.10, 3.28 ± 0.09, 3.21 ± 0.07, and 2.61 ± 0.16, and for gadoterate, 3.32 ± 0.13, 3.00 ± 0.13, 2.84 ± 0.09, and 2.72 ± 0.17. CONCLUSIONS The relaxivity of gadobutrol is significantly higher than that of gadoteridol and gadoterate at all magnetic field strengths and in plasma as well as in blood, whereas that of gadoteridol was higher than gadoterate only in plasma at 1.5 and 7 T. This is in accordance with results from 3 previous studies obtained in different media.
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Rodríguez-Galván A, Rivera M, García-López P, Medina LA, Basiuk VA. Gadolinium-containing carbon nanomaterials for magnetic resonance imaging: Trends and challenges. J Cell Mol Med 2020; 24:3779-3794. [PMID: 32154648 PMCID: PMC7171414 DOI: 10.1111/jcmm.15065] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 12/18/2019] [Accepted: 01/27/2020] [Indexed: 02/06/2023] Open
Abstract
Gadolinium-containing carbon nanomaterials are a new class of contrast agent for magnetic resonance imaging. They are characterized by a superior proton relaxivity to any current commercial gadolinium contrast agent and offer the possibility to design multifunctional contrasts. Intense efforts have been made to develop these nanomaterials because of their potential for better results than the available gadolinium contrast agents. The aim of the present work is to provide a review of the advances in research on gadolinium-containing carbon nanomaterials and their advantages over conventional gadolinium contrast agents. Due to their enhanced proton relaxivity, they can provide a reliable imaging contrast for cells, tissues or organs with much smaller doses than currently used in clinical practice, thus leading to reduced toxicity (as shown by cytotoxicity and biodistribution studies). Their active targeting capability allows for improved MRI of molecular or cellular targets, overcoming the limited labelling capability of available contrast agents (restricted to physiological irregularities during pathological conditions). Their potential of multifunctionality encompasses multimodal imaging and the combination of imaging and therapy.
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Affiliation(s)
- Andrés Rodríguez-Galván
- Unidad de Investigación Biomédica en Cáncer INCan-UNAM, Instituto Nacional de Cancerología, Ciudad de Méxi, Mexico.,Carrera de Biología, Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, Mexico
| | - Margarita Rivera
- Instituto de Física, Universidad Nacional Autónoma de México, Coyoacán, Ciudad de México, Mexico
| | - Patricia García-López
- Laboratorio de Farmacología, Subdirección de Investigación Básica, Instituto Nacional de Cancerología, Ciudad de México, Mexico
| | - Luis A Medina
- Unidad de Investigación Biomédica en Cáncer INCan-UNAM, Instituto Nacional de Cancerología, Ciudad de Méxi, Mexico.,Instituto de Física, Universidad Nacional Autónoma de México, Coyoacán, Ciudad de México, Mexico
| | - Vladimir A Basiuk
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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Ceballos-Ceballos J, Loza-Gallardo DA, Barajas-Romero MA, Cantú-Brito C, Valdés-Ferrer SI. Recognition of Brain Metastases Using Gadolinium-Enhanced SWI MRI: Proof-of-Concept Study. Front Neurol 2020; 11:5. [PMID: 32116996 PMCID: PMC7026362 DOI: 10.3389/fneur.2020.00005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 01/06/2020] [Indexed: 12/23/2022] Open
Abstract
Background and purpose: SWI MRI, a T2*-dominant MRI sequence with T1 shine-through effect, uses intrinsic structural susceptibility to create enhancement among brain structures. We evaluated whether gadolinium-enhanced SWI (SWI-Gd) improves brain metastasis detection in combination with other MRI sequences. Materials and methods: MRI images of 24 patients (46 studies) were prospectively acquired using a 1.5-T scanner. T1-weighted, unenhanced SWI (SWI-U) and SWI-Gd were evaluated blindly to clinical features by two board-certified radiologists. Results: SWI-Gd revealed more significant metastatic lesions than either T1-Gd or SWI-U (p = 0.0004 for either comparator sequence). Moreover, SWI-Gd revealed more lesions only for those patients with ≤5 lesions on T1-Gd (n = 30 studies from 16 patients; p = 0.046). Performing SWI-Gd added <5 min of scanning time with no further additional risk. Conclusions: Our findings suggest that, when added to T1-Gd and other common sequences, SWI-Gd may improve the diagnostic yield of brain metastases with only a few extra minutes of scanning time and no further risk than that of a regular gadolinium-enhanced MRI.
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Affiliation(s)
- Joel Ceballos-Ceballos
- Division of Neuroradiology, Department of Radiology, Hospital San Javier, Guadalajara, Mexico
| | - Diego A Loza-Gallardo
- Division of Neuroradiology, Department of Radiology, Hospital San Javier, Guadalajara, Mexico
| | | | - Carlos Cantú-Brito
- Department of Neurology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Sergio Iván Valdés-Ferrer
- Department of Neurology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.,Department of Infectious Diseases, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.,Center for Biomedical Science, Feinstein Institute for Medical Research, Manhasset, NY, United States
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Nickel A, Milford D, Fischer M, Bendszus M, Heiland S. Effect of contrast agent dosage on longitudinal relaxation time, signal and apparent tumor volume in glioblastoma at 9.4T. Z Med Phys 2018; 29:206-215. [PMID: 30470504 DOI: 10.1016/j.zemedi.2018.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 10/22/2018] [Accepted: 10/31/2018] [Indexed: 10/27/2022]
Abstract
INTRODUCTION Glioblastoma multiforme is the most frequent innate brain tumor and still yields an unfavorable prognosis of 15 months of survival after diagnosis. Animal models play an important role in the investigation of therapeutic strategies of brain tumors. Thereby, MRI is substantial to individual follow-up examination for therapeutic response. Contrast agent dosage at 1.5 and 3T MRI has been thoroughly tested, while there is hardly any data for 9.4T. Therefore, the aim of this study was to find the optimal contrast agent dosage at 9.4T for examination of T1 relaxation time and apparent tumor volume in an animal model. MATERIAL AND METHODS Six animals with a U-87 glioblastoma were part of this study. Scans were performed on a 9.4T MRI. The MRI protocol contained a standard T1w sequence, which was employed for tumor volumetry and signal intensity measurement after single, double and triple contrast agent dosage injections and a T2w sequence for volumetry of tumor and edema. From a T1 map, T1 relaxation times and tumor area were measured. Histologic tumor size measurements were also performed for two animals. RESULTS The mean apparent tumor volume in T1w MRI increased significantly with each additional contrast agent injection, mainly due to the increase of the hyperintense tumor rim. Volumetry based on T2w MRI resulted in a higher tumor volume than in T1w volumetry, whereas the tumor volume in T1w MRI approached the volume in T2w MRI with increasing contrast agent dosage. Histology revealed an apparent tumor volume that corresponded to the volume of the hypointense center in T1w MRI. In contrast, T1 time decrease and T1w signal increase occurred mainly in the tumor rim. CONCLUSION Increasing the contrast agent dosage led to an increase in apparent tumor volume. High-dose T1 MRI, however, overestimated the tumor volume that was determined by histology. Thereby, it can be concluded that standard contrast agent dosage is sufficient to visualize the core tumor volume in T1w MRI. Measurement of tumor volume after increasing contrast agent dosage depicts tumor core and edema, which can be due to diffusion or accumulation or both. Tumor core and edema, however, can be visualized by T2w MRI without need of additional contrast agent.
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Affiliation(s)
- Alina Nickel
- University Hospital Hamburg Eppendorf, Department of Neurology, Germany.
| | - David Milford
- University Hospital Heidelberg, Department of Neuroradiology, Germany
| | - Manuel Fischer
- University Hospital Heidelberg, Department of Neuroradiology, Germany
| | - Martin Bendszus
- University Hospital Heidelberg, Department of Neuroradiology, Germany
| | - Sabine Heiland
- University Hospital Heidelberg, Department of Neuroradiology, Germany
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Renfrew AK, O'Neill ES, Hambley TW, New EJ. Harnessing the properties of cobalt coordination complexes for biological application. Coord Chem Rev 2018. [DOI: 10.1016/j.ccr.2017.11.027] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Komura Y, Mogi T, Shimizu F, Yatabe K, Nedate J, Kanazawa H, Kawai A. [Comparison of Time-intensity Curve with Gadobenatedimeglumine and Gadobutrol on Multiphase Contrast-enhanced Breast MRI]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2018; 74:368-374. [PMID: 29681604 DOI: 10.6009/jjrt.2018_jsrt_74.4.368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The purpose of this study was to compare the time-intensity curve (TIC) on multiphase contrast-enhanced breast magnetic resonance imaging (MRI) between Gadobenatedimeglumine (Gd-DTPA) and Gadobutrol. We assessed the images of 53 cases obtained from MRI that had malignant findings by pathology from October 2015 to October 2016 in our institute. Gd-DTPA and Gadobutrol were administrated in 16 and 37 cases, respectively. The TIC of the lesion was classified according to the Kuhl's method (type I: persistent pattern, type II: plateau pattern and type III: washout pattern). Type III was the most common TIC pattern in both the groups (Gd-DTPA, 12 cases; Gadobutrol, 18 cases). Type II was the second common TIC pattern in Gadobutrol group (12 cases). As a result, there was no significant difference in TIC analysis between Gd-DTPA and gadobutrol. In conclusion, the contrast between Gd-DTPA and Gadobutrol contrast media did not differ in TIC pattern of multiphasic contrast-enhanced breast MRI.
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Affiliation(s)
- Yu Komura
- Department of Radiology, National Hospital Organization Tochigi Medical Center
| | - Takuma Mogi
- Department of Radiology, National Hospital Organization Tochigi Medical Center
| | - Fuminori Shimizu
- Department of Radiology, National Hospital Organization Tochigi Medical Center
| | - Katsuhiro Yatabe
- Department of Radiology, National Hospital Organization Numata Hospital
| | - Junkou Nedate
- Department of Radiology, National Hospital Organization Tochigi Medical Center
| | - Hidenori Kanazawa
- Department of Radiology, Japanese Red Cross Society Haga Red Cross Hospital
| | - Akira Kawai
- Department of Radiology, National Hospital Organization Tochigi Medical Center
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Yedavalli V, Sammet S. Contrast Extravasation versus Hemorrhage after Thrombectomy in Patients with Acute Stroke. J Neuroimaging 2017; 27:570-576. [PMID: 28514045 PMCID: PMC5665701 DOI: 10.1111/jon.12446] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 04/06/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE Intra-arterial recanalization postprocedural imaging in stroke patients can result in diagnostic complications due to hyperdensities on noncontrast computed tomography (CT), which may represent either contrast extravasation or intracranial hemorrhage. If these lesions are hemorrhage, then they are risk factors becoming symptomatic, which, if not distinguished, can alter clinical management. We investigate the effects of iodinated contrast on postprocedural magnetic resonance imaging (MRI) and prevalence of equivocal imaging interpretations of postprocedural extravasated contrast versus hemorrhage while identifying protocol pitfalls. METHODS We identified 10 patients diagnosed with ischemic stroke who underwent intra-arterial recanalization in a 5-year period. These patients demonstrated a hyperdensity on a postprocedural CT within 24 hours, underwent an MRI within 48 hours, and an additional confirmatory noncontrast CT at least 72 hours postprocedure. RESULTS Postprocedural MRI in all 10 stroke patients demonstrated T1 - and T2 -relaxation time changes due to residual iodine contrast agents. This lead to false positive postprocedural hemorrhage MRI interpretations in 2/10 patients, 3/10 false negative interpretations of contrast extravasation, and 5/10 equivocal interpretations suggesting extravasation or hemorrhage. Of these five cases, two were performed with gadolinium. CONCLUSION MRI done within 48 hours postprocedure can lead to false positive hemorrhage or false negative contrast extravasation interpretations in stroke patients possibly due to effects from the administered angiographic contrast. Additionally, MRI should be done both after 72 hours for confirmation and without gadolinium contrast as the effects of the gadolinium contrast and residual angiographic contrast could lead to misdiagnosis.
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Affiliation(s)
- Vivek Yedavalli
- Department of Diagnostic Radiology, Advocate Illinois Masonic Medical Center, Chicago, IL
- Department of Radiology, University of Chicago, Chicago, IL
| | - Steffen Sammet
- Department of Radiology, University of Chicago, Chicago, IL
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Characterisation of Lesions after Stereotactic Radiosurgery for Brain Metastases: Impact of Delayed Contrast Magnetic Resonance Imaging. Clin Oncol (R Coll Radiol) 2016; 29:143-150. [PMID: 27777145 DOI: 10.1016/j.clon.2016.09.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 09/21/2016] [Accepted: 09/22/2016] [Indexed: 11/22/2022]
Abstract
AIMS To investigate if brain metastases and radiation injuries after stereotactic radiosurgery (SRS) have different signal intensity (SI) time courses up to 55 min after contrast agent application and if delayed contrast magnetic resonance imaging (MRI) contributes to improve diagnostic accuracy. MATERIALS AND METHODS Thirty-four consecutive patients treated with SRS for cerebral metastases were prospectively enrolled in the study. T1-weighted images were acquired on a 3-Tesla MR unit at three time points, at 2 (TP1), 15 (TP2) and 55 (TP3) min after administering contrast agent. A simultaneous, matched-pairs approach was used for region of interest analysis of the entire contrast-enhancing lesion (SI-e), the centre (SI-c), the border of the lesion (SI-b) and the adjacent non-contrast-enhancing tissue (SI-p). SIs of brain metastases and radiation injuries after SRS were compared using a two-level, linear, mixed-effects regression model. RESULTS In total, 41 lesions were analysed: 16 metastases and 25 radiation injuries. The SI time course of SI-e, SI-c and SI-b proved to be significantly different for both entities (P < 0.001) from TP2 to TP3. The SI of 39/41 lesions increased from TP1 to TP2 for the three parameters. Radiation injuries showed a further signal increase at least for SI-c from TP2 to TP3, whereas for all the three parameters SI decreased in all metastases. CONCLUSION Brain metastases and radiation injuries after SRS have a characteristic and statistically significantly different SI time course on sequential gadolinium enhancement MRI when late MR studies are included.
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Latorzeff I, Antoni D, Gaudaire-Josset S, Feuvret L, Tallet-Richard A, Truc G, Noël G. Radiothérapie des métastases cérébrales. Cancer Radiother 2016; 20 Suppl:S80-7. [DOI: 10.1016/j.canrad.2016.07.041] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Patterns and Time Dependence of Unspecific Enhancement in Postoperative Magnetic Resonance Imaging After Glioblastoma Resection. World Neurosurg 2016; 90:440-447. [PMID: 27001238 DOI: 10.1016/j.wneu.2016.03.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/09/2016] [Accepted: 03/10/2016] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Postoperative magnetic resonance imaging (MRI) is recommended soon after glioma surgery to avoid reactive nonneoplastic contrast enhancement indistinguishable from tumor. The purpose of this study was to analyze these patterns of postoperative contrast enhancement at 3 T to define the optimal time frame for postoperative MRI. METHODS MRI for 206 glioblastoma surgeries in 173 patients who underwent pre- and postoperative and at least 1 follow-up 3T MRI for each surgery were analyzed retrospectively. Postoperative MRI was assessed in consensus by 2 neuroradiologists, blinded to the time after surgery. Postoperative contrast enhancement marginal to the resection cavity was analyzed and classified as vascular, linear, or nodular. The cause of the contrast enhancement (ie, reactive vs. tumor) was assessed by comparing pre-, postoperative, and follow-up MRI. RESULTS Within 45 hours after surgery, reactive enhancement appeared in 17.9% of cases. After 45 hours, the fraction of reactive changes increased to 34.1%. Linear enhancement was more often reactive (66.1%, 39/59 cases), whereas nodular enhancement was mainly residual tumor (93.2%, 68/73 cases). Specificity of nodular enhancement was high for tumor recurrence/tumor progression (91.5%). CONCLUSIONS To avoid an increasing number of MRIs with reactive contrast enhancement, postoperative MRI at 3 T should be performed within 45 hours after surgery. However, reactive contrast enhancement can occur at all time points. In these cases, the pattern of the contrast enhancement may help to differentiate its cause.
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Lescher S, Schniewindt S, Jurcoane A, Senft C, Hattingen E. Time window for postoperative reactive enhancement after resection of brain tumors: less than 72 hours. Neurosurg Focus 2014; 37:E3. [DOI: 10.3171/2014.9.focus14479] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Early postoperative MRI within 72 hours after brain tumor surgery is commonly used to assess residual contrast-enhancing tumor. The 72-hour window is commonly accepted because previous 1.5-T MRI studies have not found confounding postoperative reactive contrast enhancement in this time frame. The sensitivity to detect contrast enhancement increases with the field strengths. Therefore, the authors aimed to assess whether the 72-hour window is also appropriate for the MRI scanner with a field strength of 3 T.
Methods
The authors retrospectively analyzed findings on early postsurgical MR images acquired in 46 patients treated for high-grade gliomas. They performed 3-T MRI within 7 days before surgery and within 72 hours thereafter. The appearance of enhancement was categorized as postoperative reactive enhancement or tumoral enhancement by comparison with the pattern and location of presurgical enhancing tumor.
Results
Postoperative reactive enhancement was present in 15 patients (32.6%). This enhancement, not seen on presurgical MRI, had a marginal or leptomeningeal/dural pattern. In 13 patients (28.3%) postsurgical enhancement was found within the first 72 postoperative hours, with the earliest seen 22:57 hours after surgery. Subsequent MR scans in patients with postoperative reactive enhancement did not reveal tumor recurrence in these regions.
Conclusions
Postoperative reactive enhancement earlier than 72 hours after brain tumor surgery can be expected in about one-third of the cases in which a 3-T scanner is used. This might be due to the higher enhancement-to-brain contrast at higher field strengths. Therefore, the time window of 72 hours does not prevent reactive enhancement, which, however, can be recognized as such comparing it with presurgical enhancing tumor.
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Affiliation(s)
| | | | | | - Christian Senft
- 2Department of Neurosurgery, Hospital of Goethe University, Frankfurt am Main, Germany
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Crombé A, Saranathan M, Ruet A, Durieux M, de Roquefeuil E, Ouallet JC, Brochet B, Dousset V, Tourdias T. MS lesions are better detected with 3D T1 gradient-echo than with 2D T1 spin-echo gadolinium-enhanced imaging at 3T. AJNR Am J Neuroradiol 2014; 36:501-7. [PMID: 25376810 DOI: 10.3174/ajnr.a4152] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE In multiple sclerosis, gadolinium enhancement is used to classify lesions as active. Regarding the need for a standardized and accurate method for detection of multiple sclerosis activity, we compared 2D-spin-echo with 3D-gradient-echo T1WI for the detection of gadolinium-enhancing MS lesions. MATERIALS AND METHODS Fifty-eight patients with MS were prospectively imaged at 3T by using both 2D-spin-echo and 3D-gradient recalled-echo T1WI in random order after the injection of gadolinium. Blinded and independent evaluation was performed by a junior and a senior reader to count gadolinium-enhancing lesions and to characterize their location, size, pattern of enhancement, and the relative contrast between enhancing lesions and the adjacent white matter. Finally, the SNR and relative contrast of gadolinium-enhancing lesions were computed for both sequences by using simulations. RESULTS Significantly more gadolinium-enhancing lesions were reported on 3D-gradient recalled-echo than on 2D-spin-echo (n = 59 versus n = 30 for the junior reader, P = .021; n = 77 versus n = 61 for the senior reader, P = .017). The difference between the 2 readers was significant on 2D-spin-echo (P = .044), for which images were less reproducible (κ = 0.51) than for 3D-gradient recalled-echo (κ = 0.65). Further comparisons showed that there were statistically more small lesions (<5 mm) on 3D-gradient recalled-echo than on 2D-spin-echo (P = .04), while other features were similar. Theoretic results from simulations predicted SNR and lesion contrast for 3D-gradient recalled-echo to be better than for 2D-spin-echo for visualization of small enhancing lesions and were, therefore, consistent with clinical observations. CONCLUSIONS At 3T, 3D-gradient recalled-echo provides a higher detection rate of gadolinium-enhancing lesions, especially those with smaller size, with a better reproducibility; this finding suggests using 3D-gradient recalled-echo to detect MS activity, with potential impact in initiation, monitoring, and optimization of therapy.
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Affiliation(s)
- A Crombé
- From the Service de NeuroImagerie Diagnostique et Thérapeutique (A.C., M.D., E.d.R., V.D., T.T.)
| | - M Saranathan
- Department of Radiology (M.S.), Stanford University, Stanford, California
| | - A Ruet
- Pôle de Neurosciences Cliniques (A.R., J.C.O., B.B.), Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France INSERM U862 (A.R., B.B., V.D., T.T.), Neurocentre Magendie, Université de Bordeaux, Bordeaux, France
| | - M Durieux
- From the Service de NeuroImagerie Diagnostique et Thérapeutique (A.C., M.D., E.d.R., V.D., T.T.)
| | - E de Roquefeuil
- From the Service de NeuroImagerie Diagnostique et Thérapeutique (A.C., M.D., E.d.R., V.D., T.T.)
| | - J C Ouallet
- Pôle de Neurosciences Cliniques (A.R., J.C.O., B.B.), Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France
| | - B Brochet
- Pôle de Neurosciences Cliniques (A.R., J.C.O., B.B.), Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France INSERM U862 (A.R., B.B., V.D., T.T.), Neurocentre Magendie, Université de Bordeaux, Bordeaux, France
| | - V Dousset
- From the Service de NeuroImagerie Diagnostique et Thérapeutique (A.C., M.D., E.d.R., V.D., T.T.) INSERM U862 (A.R., B.B., V.D., T.T.), Neurocentre Magendie, Université de Bordeaux, Bordeaux, France
| | - T Tourdias
- From the Service de NeuroImagerie Diagnostique et Thérapeutique (A.C., M.D., E.d.R., V.D., T.T.) INSERM U862 (A.R., B.B., V.D., T.T.), Neurocentre Magendie, Université de Bordeaux, Bordeaux, France.
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Ugas MA, Huynh BH, Fox MG, Patrie JT, Gaskin CM. MR Arthrography: Impact of Steroids, Local Anesthetics, and Iodinated Contrast Material on Gadolinium Signal Intensity in Phantoms at 1.5 and 3.0 T. Radiology 2014; 272:475-83. [DOI: 10.1148/radiol.14132352] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Cassetta M, Barchetti F, Pranno N, Marini M. Comparing proton density and turbo spin echo T2 weighted static sequences with dynamic half-Fourier single-shot TSE pulse sequence at 3.0 T in diagnosis of temporomandibular joint disorders: a prospective study. Dentomaxillofac Radiol 2014; 43:20130387. [PMID: 24720606 DOI: 10.1259/dmfr.20130387] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES The aim of this prospective study was to compare dynamic and static sequences in the evaluation of temporomandibular joint disorders using a 3.0 -T imaging unit. METHODS 194 patients were evaluated by static (double echo proton density weighted/turbo spin echo T2 weighted sequences) and dynamic (half-Fourier single-shot turbo spin echo sequences)imaging. Two radiologists evaluated in consensus the quality of images, the disc position and morphological alterations. The Kendall rank correlation coefficient (τ-b) was used to compare the qualitative rating between static and dynamic sequences. Cohen's kappa coefficient (k) was used to assess the agreement of disc position and morphological alterations between both sequences. The intraclass correlation coefficient was used to calculate the intraobserver variability. The significance was set at p ≤ 0.05. RESULTS The correlation between both sequences in the qualitative evaluation was τ-b = 0.632. The agreement between both techniques in the evaluation of disc position was k = 0.856. The agreement between both techniques in assessing the morphological alterations was k = 0.487. In the static sequences, the intraclass correlation coefficient was 0.915 in the qualitative evaluation, 0.873 in the evaluation of disc position and 0.934 in the assessment of morphological alterations. In the dynamic sequences, the intraclass correlation coefficient was 0.785 in the qualitative evaluation, 0.935 in the evaluation of disc position and 0.826 in the assessment of morphological alterations. CONCLUSIONS Static imaging remains the gold standard in the evaluation of the temporomandibular joint. Dynamic imaging is a valuable tool that can provide additional information about topographic changes in the disc-condyle relationship.
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Affiliation(s)
- M Cassetta
- Department of Oral and Maxillofacial Sciences, School of Dentistry, "Sapienza" University of Rome, Rome, Italy
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17
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Nöbauer-Huhmann IM. [Researcher of the month]. Wien Klin Wochenschr 2013; 125:730-1. [PMID: 24240616 DOI: 10.1007/s00508-013-0465-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Iris-Melanie Nöbauer-Huhmann
- Abteilung für Neuroradiologie und Muskuloskeletale Radiologie Medizinische Universität Wien, Universitätsklinik für Radiologie und Nuklearmedizin, Währinger Gürtel 18-20, 1090, Wien, Österreich,
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Dynamic aggregation of the mid-sized gadolinium complex {Ph4[Gd(DTTA)(H2O)2]− 3}. J Biol Inorg Chem 2013; 19:145-59. [DOI: 10.1007/s00775-013-1036-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 08/14/2013] [Indexed: 12/28/2022]
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19
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Dym RJ, Chernyak V, Rozenblit AM. MR imaging of renal collecting system with gadoxetate disodium: Feasibility for MR urography. J Magn Reson Imaging 2013; 38:816-23. [DOI: 10.1002/jmri.24059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 01/07/2012] [Indexed: 11/06/2022] Open
Affiliation(s)
- R. Joshua Dym
- Department of Radiology; Albert Einstein College of Medicine and Montefiore Medical Center; Bronx New York USA
| | - Victoria Chernyak
- Department of Radiology; Albert Einstein College of Medicine and Montefiore Medical Center; Bronx New York USA
| | - Alla M. Rozenblit
- Department of Radiology; Albert Einstein College of Medicine and Montefiore Medical Center; Bronx New York USA
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20
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Essig M, Dinkel J, Gutierrez JE. Use of Contrast Media in Neuroimaging. Magn Reson Imaging Clin N Am 2012; 20:633-48. [DOI: 10.1016/j.mric.2012.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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21
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Ke Feng, Hollingsworth NA, McDougall MP, Wright SM. A 64-channel transmitter for investigating parallel transmit MRI. IEEE Trans Biomed Eng 2012; 59:2152-60. [PMID: 22552545 DOI: 10.1109/tbme.2012.2196797] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Multiple channel radiofrequency (RF) transmitters are being used in magnetic resonance imaging to investigate a number of active research topics, including transmit SENSE and B(1) shimming. Presently, the cost and availability of multiple channel transmitters restricts their use to relatively few sites. This paper describes the development and testing of a relatively inexpensive transmit system that can be easily duplicated by users with a reasonable level of RF hardware design experience. The system described here consists of 64 channels, each with 100 W peak output level. The hardware is modular at the level of four channels, easily accommodating larger or smaller channel counts. Unique aspects of the system include the use of vector modulators to replace more complex IQ direct digital modulators, 100 W MOSFET RF amplifiers with partial microstrip matching networks, and the use of digital potentiometers to replace more complex and costly digital-to-analog converters to control the amplitude and phase of each channel. Although mainly designed for B(1) shimming, the system is capable of dynamic modulation necessary for transmit SENSE by replacing the digital potentiometers controlling the vector modulators with commercially available analog output boards. The system design is discussed in detail and bench and imaging data are shown, demonstrating the ability to perform phase and amplitude control for B(1) shimming as well as dynamic modulation for transmitting complex RF pulses.
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Affiliation(s)
- Ke Feng
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA.
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22
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Sarantopoulos A, Beziere N, Ntziachristos V. Optical and Opto-Acoustic Interventional Imaging. Ann Biomed Eng 2012; 40:346-66. [DOI: 10.1007/s10439-011-0501-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 12/23/2011] [Indexed: 12/20/2022]
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23
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Wang W, Dong H, Pacheco V, Willbold D, Zhang Y, Offenhaeusser A, Hartmann R, Weirich TE, Ma P, Krause HJ, Gu Z. Relaxation Behavior Study of Ultrasmall Superparamagnetic Iron Oxide Nanoparticles at Ultralow and Ultrahigh Magnetic Fields. J Phys Chem B 2011; 115:14789-93. [DOI: 10.1021/jp2066138] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wei Wang
- National Engineering Research Center for Biomaterials, Sichuan University, 610064 Chengdu, China
- Peter Gruenberg Institute (PGI-8), Research Center Juelich, 52425 Juelich, Germany
| | - Hui Dong
- Peter Gruenberg Institute (PGI-8), Research Center Juelich, 52425 Juelich, Germany
- State key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
| | - Victor Pacheco
- Institute of Complex Systems (ICS-6), Research Center Juelich, 52425 Juelich, Germany
- Central Division of Analytical Chemistry (ZCH), Research Center Juelich, 52425 Juelich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Dieter Willbold
- Institute of Complex Systems (ICS-6), Research Center Juelich, 52425 Juelich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Yi Zhang
- Peter Gruenberg Institute (PGI-8), Research Center Juelich, 52425 Juelich, Germany
| | | | - Rudolf Hartmann
- Institute of Complex Systems (ICS-6), Research Center Juelich, 52425 Juelich, Germany
| | - Thomas E. Weirich
- Central Facility for Electron Microscopy and Institute of Crystallography, RWTH Aachen University, 52074 Aachen, Germany
| | - Peixiang Ma
- Institute of Complex Systems (ICS-6), Research Center Juelich, 52425 Juelich, Germany
| | - Hans-Joachim Krause
- Peter Gruenberg Institute (PGI-8), Research Center Juelich, 52425 Juelich, Germany
| | - Zhongwei Gu
- National Engineering Research Center for Biomaterials, Sichuan University, 610064 Chengdu, China
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24
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Optimization of gadolinium-based MRI contrast agents for high magnetic-field applications. Future Med Chem 2011; 2:385-96. [PMID: 21426173 DOI: 10.4155/fmc.09.174] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The search for higher spatial resolution and better sensitivity stimulates the development of high-field (3 T) and ultrahigh field (>3 T) MRI scanners. Gadolinium-based MRI contrast agents, commercial ones used in clinics, as well as recently developed more efficient ones, become less and less effective as the magnetic field is increased above 3 T and, therefore, special contrast agents for ultrahigh-field MRI have to be developed. As the relaxivity, defined as relaxation enhancement per Gd-ion, is rather limited, marked boosts in performance can only be achieved by creating systems transporting many paramagnetic centers to the desired site. To obtain maximum efficiency gadolinium chelates with more than one water molecule in the first coordination sphere must be used. The rotational correlation time should be in the range of 0.5-1 ns and the residence time of first sphere water molecules should be short (<10 ns).
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25
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Miéville P, Jaccard H, Reviriego F, Tripier R, Helm L. Synthesis, complexation and NMR relaxation properties of Gd3+ complexes of Mes(DO3A)3. Dalton Trans 2011; 40:4260-7. [DOI: 10.1039/c0dt01597k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Lignelli A, Khandji AG. Review of Imaging Techniques in the Diagnosis and Management of Brain Metastases. Neurosurg Clin N Am 2011; 22:15-25, v. [DOI: 10.1016/j.nec.2010.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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27
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Arlinghaus LR, Li X, Levy M, Smith D, Welch EB, Gore JC, Yankeelov TE. Current and future trends in magnetic resonance imaging assessments of the response of breast tumors to neoadjuvant chemotherapy. JOURNAL OF ONCOLOGY 2010; 2010:919620. [PMID: 20953332 PMCID: PMC2952974 DOI: 10.1155/2010/919620] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 07/07/2010] [Accepted: 08/11/2010] [Indexed: 11/18/2022]
Abstract
The current state-of-the-art assessment of treatment response in breast cancer is based on the response evaluation criteria in solid tumors (RECIST). RECIST reports on changes in gross morphology and divides response into one of four categories. In this paper we highlight how dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted MRI (DW-MRI) may be able to offer earlier, and more precise, information on treatment response in the neoadjuvant setting than RECIST. We then describe how longitudinal registration of breast images and the incorporation of intelligent bioinformatics approaches with imaging data have the potential to increase the sensitivity of assessing treatment response. We conclude with a discussion of the potential benefits of breast MRI at the higher field strength of 3T. For each of these areas, we provide a review, illustrative examples from clinical trials, and offer insights into future research directions.
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Affiliation(s)
- Lori R. Arlinghaus
- Department of Radiology and Radiological Sciences, Institute of Imaging Science, Nashville, TN 37232-2310, USA
| | - Xia Li
- Department of Radiology and Radiological Sciences, Institute of Imaging Science, Nashville, TN 37232-2310, USA
| | - Mia Levy
- Department of Biomedical Informatics, Institute of Imaging Science, Nashville, TN 37232-2310, USA
- Department of Medicine, Institute of Imaging Science, Nashville, TN 37232-2310, USA
| | - David Smith
- Department of Radiology and Radiological Sciences, Institute of Imaging Science, Nashville, TN 37232-2310, USA
| | - E. Brian Welch
- Department of Radiology and Radiological Sciences, Institute of Imaging Science, Nashville, TN 37232-2310, USA
| | - John C. Gore
- Department of Radiology and Radiological Sciences, Institute of Imaging Science, Nashville, TN 37232-2310, USA
- Department of Biomedical Engineering, Institute of Imaging Science, Nashville, TN 37232-2310, USA
- Department of Physics and Astronomy, Institute of Imaging Science, Nashville, TN 37232-2310, USA
- Department of Molecular Physiology and Biophysics, Institute of Imaging Science, Nashville, TN 37232-2310, USA
| | - Thomas E. Yankeelov
- Department of Radiology and Radiological Sciences, Institute of Imaging Science, Nashville, TN 37232-2310, USA
- Department of Biomedical Engineering, Institute of Imaging Science, Nashville, TN 37232-2310, USA
- Department of Physics and Astronomy, Institute of Imaging Science, Nashville, TN 37232-2310, USA
- Department of Cancer Biology, Institute of Imaging Science, Nashville, TN 37232-2310, USA
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28
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de Backer ME, Nabuurs RJA, van Buchem MA, van der Weerd L. MR-based molecular imaging of the brain: the next frontier. AJNR Am J Neuroradiol 2010; 31:1577-83. [PMID: 20864520 DOI: 10.3174/ajnr.a2264] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In the foreseeable future, the MI field could greatly assist neuroradiologists. Reporter molecules provide information on specific molecular or cellular events that could not only aid diagnosis but potentially differentiate stages of disorders and treatments. To accomplish this, reporter molecules literally need to pass a barrier, the BBB, which is designed to repel nonessential molecules from the brain. Although this is not a trivial task, several transport systems could be tricked into guiding molecules into the brain. The noninvasive nature in conjunction with a wide availability makes MR imaging particularly suitable for longitudinal neurologic imaging studies. This review explains the principles of MR imaging contrast, delineates different types of reporter molecules, and describes strategies to transport reporters into the brain. It also discusses recent advances in MR imaging hardware, pulse sequences, the development of targeted reporter probes, and future directions of the MR neuroimaging field.
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Affiliation(s)
- M E de Backer
- Molecular Imaging Laboratories, Leiden, the Netherlands
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29
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Towards highly efficient, intelligent and bimodal imaging probes: Novel approaches provided by lanthanide coordination chemistry. CR CHIM 2010. [DOI: 10.1016/j.crci.2010.03.026] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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30
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Meaney JFM, Fagan AJ, Beddy P. Magnetic resonance angiography of abdominal vessels at 3 T. Top Magn Reson Imaging 2010; 21:189-197. [PMID: 21847038 DOI: 10.1097/rmr.0b013e318228ca49] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Magnetic resonance angiography (MRA) has evolved significantly since first described in the early 1990s. Unrivaled image quality and freedom from artifacts has made it a reliable and widely utilized technique. Imaging at 3 T offers the potential for higher resolutions images with better temporal resolution compared to 1.5 T. This article will review the technique and contrast agents required to perform MRA at 3 T and the relevant clinical applications. We also discuss non-contrast enhanced MRA in the era of nephrogenic systemic fibrosis and future prospect for MRA at 3 T.
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Affiliation(s)
- James F M Meaney
- Centre for Advanced Magnetic Resonance Imaging, St. James's Hospital, Dublin, Ireland.
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31
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Anderson CJ, Bulte JWM, Chen K, Chen X, Khaw BA, Shokeen M, Wooley KL, VanBrocklin HF. Design of targeted cardiovascular molecular imaging probes. J Nucl Med 2010; 51 Suppl 1:3S-17S. [PMID: 20395345 DOI: 10.2967/jnumed.109.068130] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Molecular imaging relies on the development of sensitive and specific probes coupled with imaging hardware and software to provide information about the molecular status of a disease and its response to therapy, which are important aspects of disease management. As genomic and proteomic information from a variety of cardiovascular diseases becomes available, new cellular and molecular targets will provide an imaging readout of fundamental disease processes. A review of the development and application of several cardiovascular probes is presented here. Strategies for labeling cells with superparamagnetic iron oxide nanoparticles enable monitoring of the delivery of stem cell therapies. Small molecules and biologics (e.g., proteins and antibodies) with high affinity and specificity for cell surface receptors or cellular proteins as well as enzyme substrates or inhibitors may be labeled with single-photon-emitting or positron-emitting isotopes for nuclear molecular imaging applications. Labeling of bispecific antibodies with single-photon-emitting isotopes coupled with a pretargeting strategy may be used to enhance signal accumulation in small lesions. Emerging nanomaterials will provide platforms that have various sizes and structures and that may be used to develop multimeric, multimodal molecular imaging agents to probe one or more targets simultaneously. These platforms may be chemically manipulated to afford molecules with specific targeting and clearance properties. These examples of molecular imaging probes are characteristic of the multidisciplinary nature of the extraction of advanced biochemical information that will enhance diagnostic evaluation and drug development and predict clinical outcomes, fulfilling the promise of personalized medicine and improved patient care.
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Affiliation(s)
- Carolyn J Anderson
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University, St. Louis, Missouri, USA
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32
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High Field Cardiac Magnetic Resonance Imaging – Current and Future Perspectives. Heart Lung Circ 2010; 19:145-53. [DOI: 10.1016/j.hlc.2009.11.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 11/26/2009] [Accepted: 11/29/2009] [Indexed: 01/18/2023]
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Hsu YY, Yang WS, Lim KE, Liu HL. Vessel size imaging using dual contrast agent injections. J Magn Reson Imaging 2010; 30:1078-84. [PMID: 19856441 DOI: 10.1002/jmri.21960] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To investigate the feasibility of a vessel size imaging (VSI) technique with separate contrast agent injections for evaluation of the vessel caliber in normal tissues and in brain tumors. MATERIALS AND METHODS Computer simulation was first performed to assess the potential errors in the estimation of vessel caliber that could result from time shifts between the dual contrast agent injections. Eight patients (four female, four male, 37-77 years old) with brain tumors (three high-grade gliomas, two low-grade gliomas, and three meningiomas) were recruited for clinical study. Dynamic susceptibility contrast magnetic resonance imaging (MRI) using gradient echo (GE) and spin echo (SE) echo-planar imaging sequences were performed separately with a 10-minute interval on a 3.0T scanner. Vessel caliber maps were calculated and analyzed in regions of interest at cortical gray matter (GM), thalamus, white matter (WM), and tumors. RESULTS From the computer simulation, the error of vessel caliber measurement was less than 8% when the difference between the time-to-peak of the GE and the SE studies was 1.5 seconds, and reduced to within 5% when the difference was 1 second. From the patient datasets of a 64 x 64 matrix, the estimated vessel calibers were 37.4 +/- 12.9 microm for cortical gray matter, 20.7 +/- 8.8 microm for thalamus, and 15.0 +/- 5.1 microm for white matter, comparable to results in the literature. Two patients had a VSI with 128 x 128 matrix and showed similar results in vessel calibers of normal tissues. All the tumors had larger mean vessel diameter than normal-appearing tissues. The difference in vascular size between normal tissue and tumor was demonstrated clearly in both the VSIs of regular and high spatial resolution. CONCLUSION This study suggests that VSI with a dual injection method is a feasible technique for estimating microvascular calibers of normal tissues and brain tumors in clinical scanners.
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Affiliation(s)
- Yuan-Yu Hsu
- Department of Medical Imaging, Buddhist Tzu Chi General Hospital, Taipei, and School of Medicine, Tzu Chi University, Hualien, Taiwan
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Leyendecker JR, Clingan MJ. Magnetic Resonance Urography Update—Are We There Yet? Semin Ultrasound CT MR 2009; 30:246-57. [DOI: 10.1053/j.sult.2009.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Rumboldt Z, Rowley HA, Steinberg F, Maldjian JA, Ruscalleda J, Gustafsson L, Bastianello S. Multicenter, double-blind, randomized, intra-individual crossover comparison of gadobenate dimeglumine and gadopentetate dimeglumine in MRI of brain tumors at 3 tesla. J Magn Reson Imaging 2009; 29:760-7. [PMID: 19306364 DOI: 10.1002/jmri.21695] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To prospectively compare 0.1 mmol/kg doses of gadobenate dimeglumine and gadopentetate dimeglumine for contrast-enhanced MRI of brain lesions at 3 Tesla (T). MATERIALS AND METHODS Forty-six randomized patients underwent a first examination with gadobenate dimeglumine (n = 23) or gadopentetate dimeglumine (n = 23) and then, after 2-7 days, a second examination with the other agent. Contrast administration (volume, rate), sequence parameters (T1wSE; T1wGRE), and interval between injection and image acquisition were identical for examinations in each patient. Three blinded neuroradiologists evaluated images qualitatively (lesion delineation, lesion enhancement, global preference) and quantitatively (lesion-to-brain ratio [LBR], contrast-to-noise ratio [CNR], % lesion enhancement). Differences were assessed using Wilcoxon's signed-rank test. Reader agreement was determined using kappa (kappa) statistics. RESULTS There were no demographic differences between groups. The three readers preferred gadobenate dimeglumine globally in 22 (53.7%), 21 (51.2%), and 27 (65.9%) patients, respectively, compared with 0, 1, and 0 patients for gadopentetate dimeglumine. Similar significant (P < 0.001) preference was expressed for lesion border delineation and enhancement. Reader agreement was consistently good (kappa = 0.48-0.64). Significantly (P < 0.05) higher LBR (+43.5- 61.2%), CNR (+51.3-147.6%), and % lesion enhancement (+45.9-49.5%) was noted with gadobenate dimeglumine. CONCLUSION Brain lesion depiction at 3T is significantly improved with 0.1 mmol/kg gadobenate dimeglumine.
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Affiliation(s)
- Zoran Rumboldt
- Medical University of South Carolina, Department of Radiology, Charleston, SC, USA.
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Silverman SG, Leyendecker JR, Amis ES. What Is the Current Role of CT Urography and MR Urography in the Evaluation of the Urinary Tract? Radiology 2009; 250:309-23. [DOI: 10.1148/radiol.2502080534] [Citation(s) in RCA: 218] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Schmid-Schwap M, Drahanowsky W, Bristela M, Kundi M, Piehslinger E, Robinson S. Diagnosis of temporomandibular dysfunction syndrome—image quality at 1.5 and 3.0 Tesla magnetic resonance imaging. Eur Radiol 2009; 19:1239-45. [DOI: 10.1007/s00330-008-1264-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 10/31/2008] [Accepted: 11/12/2008] [Indexed: 10/21/2022]
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38
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Design and function of metal complexes as contrast agents in MRI. ADVANCES IN INORGANIC CHEMISTRY 2009. [DOI: 10.1016/s0898-8838(09)00202-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Plein S, Schwitter J, Suerder D, Greenwood JP, Boesiger P, Kozerke S. k-Space and time sensitivity encoding-accelerated myocardial perfusion MR imaging at 3.0 T: comparison with 1.5 T. Radiology 2008; 249:493-500. [PMID: 18936311 DOI: 10.1148/radiol.2492080017] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE To determine the feasibility and diagnostic accuracy of high-spatial-resolution myocardial perfusion magnetic resonance (MR) imaging at 3.0 T by using k-space and time (k-t) domain undersampling with sensitivity encoding (SENSE), or k-t SENSE. Data were compared with results of k-t SENSE-accelerated high-spatial-resolution perfusion MR imaging at 1.5 T and standard-resolution acquisition at 3.0 T. MATERIALS AND METHODS The study was reviewed and approved by the local ethics review board; informed consent was obtained. k-t SENSE perfusion MR imaging was performed at 1.5 and 3.0 T (fivefold k-t SENSE acceleration; spatial resolution, 1.3 x 1.3 x 10 mm). Fourteen volunteers were studied at rest; 37 patients were studied during adenosine-induced stress. In volunteers, comparison was also made with standard-resolution (2.5 x 2.5 x 10 mm) twofold SENSE perfusion MR imaging results at 3.0 T. Image quality, artifact scores, signal-to-noise ratios (SNRs), and contrast enhancement ratios were derived. In patients, diagnostic accuracy of visual analysis to detect stenosis of more than 50% narrowing in diameter at quantitative coronary angiography was determined by using receiver operator characteristic (ROC) analysis. RESULTS In volunteers, image quality and artifact scores were similar for 3.0- and 1.5-T k-t SENSE perfusion MR imaging, while SNR was higher (11.6 vs 5.6) and contrast enhancement ratio was lower (1.1 vs 1.5, P = .012) at 3.0 T. Compared with standard-resolution perfusion MR imaging, image quality was higher for 3.0-T k-t SENSE (3.6 vs 3.1, P = .04), endocardial dark rim artifacts were reduced (artifact thickness, 1.6 vs 2.4 mm, P < .001), and contrast enhancement ratios were similar. In patients, areas under the ROC curve for detection of coronary stenosis were 0.89 and 0.80 (P = .21) for 3.0 and 1.5 T, respectively. CONCLUSION k-t SENSE-accelerated high-spatial-resolution perfusion MR imaging at 3.0 T is feasible, with similar artifacts and diagnostic accuracy as those at 1.5 T. Compared with standard-resolution twofold SENSE perfusion MR imaging, image quality at k-t SENSE MR imaging is improved and artifacts are reduced.
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Affiliation(s)
- Sven Plein
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.
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Abstract
MR imaging plays a major role in the assessment of pediatric musculoskeletal disease. Compared with 1.5 T MR imaging, 3 T magnets provide images with an increased signal-to-noise ratio, which is particularly helpful when assessing small body parts and structures in children. This article discusses the advantages and challenges associated with musculoskeletal MR imaging at 3 T, basic scanning protocols, image optimization techniques, and specific clinical applications in a pediatric population.
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Affiliation(s)
- James S Meyer
- Department of Radiology, Children's Hospital of Philadelphia, 34th Street and Civic Center Boulevard, Philadelphia, PA 19104, USA.
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Signal intensity of motor and sensory cortices on T2-weighted and FLAIR images: intraindividual comparison of 1.5T and 3T MRI. Eur Radiol 2008; 18:2949-55. [DOI: 10.1007/s00330-008-1069-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2006] [Revised: 04/29/2008] [Accepted: 05/03/2008] [Indexed: 11/25/2022]
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42
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Jun Y, Lee J, Cheon J. Chemisches Design von leistungsfähigen Nanosonden für die Kernspintomographie. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200701674] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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43
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Jun Y, Lee J, Cheon J. Chemical Design of Nanoparticle Probes for High‐Performance Magnetic Resonance Imaging. Angew Chem Int Ed Engl 2008; 47:5122-35. [DOI: 10.1002/anie.200701674] [Citation(s) in RCA: 749] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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44
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Difference in enhancement between spin echo and 3-dimensional fast spoiled gradient recalled acquisition in steady state magnetic resonance imaging of brain metastasis at 3-T magnetic resonance imaging. J Comput Assist Tomogr 2008; 32:313-9. [PMID: 18379324 DOI: 10.1097/rct.0b013e318074fd9d] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To compare the enhancement of brain metastasis between 3-dimensional fast spoiled gradient recalled acquisition in the steady state (3DFSPGR) and spin echo (SE) T1-weighted imaging at 3-T magnetic resonance imaging. METHODS The subjects comprised 18 patients with 81 suspected brain metastases. Axial SE and 3DFSPGR images were obtained before and after gadoteridol injection. The signal intensity of each tumor was measured for each sequence; the enhancement and contrast rates were also calculated. RESULTS For equivalent slice thicknesses, the enhancement and contrast rates of the 3DFSPGR images were lower than those of the SE images (<0.05), whereas for the thin slices, the rates were higher for the 3DFSPGR images (P < 0.01). CONCLUSIONS On 3-T magnetic resonance imaging, the enhancement of 3DFSPGR images was less than that of the SE images under the same conditions, but not to a fatal degree, and thin slice 3DFSPGR imaging is therefore considered to be useful for detecting small lesions, when given a high dose of contrast agent and a suitable scanning delay time.
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45
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Andreisek G, Froehlich JM, Hodler J, Weishaupt D, Beutler V, Pfirrmann CWA, Boesch C, Nanz D. Direct MR arthrography at 1.5 and 3.0 T: signal dependence on gadolinium and iodine concentrations--phantom study. Radiology 2008; 247:706-16. [PMID: 18403628 DOI: 10.1148/radiol.2473071013] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To prospectively quantify in vitro the influence of gadopentetate dimeglumine and ioversol on the magnetic resonance (MR) imaging signal observed with a variety of musculoskeletal pulse sequences to predict optimum gadolinium concentrations for direct MR arthrography at 1.5 and 3.0 T. MATERIALS AND METHODS In an in vitro study, T1 and T2 relaxation times of three dilution series of gadopentetate dimeglumine (concentration, 0-20.0 mmol gadolinium per liter) at ioversol concentrations with iodine concentration of 0, 236.4, and 1182 mmol iodine per liter (corresponding to 0, 30, and 150 mg of iodine per milliliter) were measured at 1.5 and 3.0 T. The relaxation rate dependence on concentrations of gadolinium and iodine was analytically modeled, and continuous profiles of signal versus gadolinium concentration were calculated for 10 pulse sequences used in current musculoskeletal imaging. After fitting to experimental discrete profiles, maximum signal-to-noise ratio (SNR), gadolinium concentration with maximum SNR, and range of gadolinium concentration with 90% of maximum SNR were derived. The overall influence of field strength and iodine concentration on these parameters was assessed by using t tests. The deviation of simulated from experimental signal-response profiles was assessed with the autocorrelation of the residuals. RESULTS The model reproduced relaxation rates of 0.37-38.24 sec(-1), with a mean error of 4.5%. Calculated SNR profiles matched the discrete experimental profiles, with autocorrelation of the residuals divided by the mean of less than 5.0. Admixture of ioversol consistently reduced T1 and T2, narrowed optimum gadolinium concentration ranges (P = .004-.006), and reduced maximum SNR (P < .001 to not significant). Optimum gadolinium concentration was 0.7-3.4 mmol/L at both field strengths. At 3.0 T, maximum SNR was up to 75% higher than at 1.5 T. CONCLUSION Admixture of ioversol to gadopentetate dimeglumine solutions results in a consistent additional relaxation enhancement, which can be analytically modeled to allow a near-quantitative a priori optimized match of contrast media concentrations and imaging protocol for a broad variety of pulse sequences.
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Affiliation(s)
- Gustav Andreisek
- Institute for Diagnostic Radiology and Department of Medical Radiology, University Hospital Zurich, Raemistrasse 100, 8091 Zurich, Switzerland.
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46
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47
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Stalder AF, Elverfeldt DV, Paul D, Hennig J, Markl M. Variable echo time imaging: signal characteristics of 1-M gadobutrol contrast agent at 1.5 and 3T. Magn Reson Med 2008; 59:113-23. [PMID: 18058940 DOI: 10.1002/mrm.21345] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Gadobutrol (Gd-Bt; Gadovist(R), Schering AG) is a 1-M Gadolinium (Gd)-based contrast agent. Its higher Gd concentration allows for reduction of injection volumes in first pass contrast-enhanced MR angiography (CE-MRA) and should increase bolus sharpness and image quality. However, ambivalent results were reported. In order to explore the performance of 1-M contrast agents such as Gd-Bt and its dependence on molecular environment and temperature, signal characteristics were analyzed for a series of increasing Gd-Bt concentrations for different temperature-controlled samples in water and human blood plasma. Relaxation times, relaxivities, and signal-concentration curves were assessed for several Gd-Bt concentrations in water at 20 degrees C and 37 degrees C and in plasma at 37 degrees C for 1.5T and 3T. Gd-Bt concentration influence on signal intensity (SI) could be effectively simulated and compared with experimental measurements as well as simulations with other contrast agents at realistic in vivo concentrations. Particular attention was given to T(2)- and T(*) (2)-induced losses at high concentrations, which annihilate benefits from T(1) shortening. Based on these findings, variable echo time (VTE) approaches with readout bandwidth varying with k-space position were explored in order to enhance the signal to noise performance of gradient echo imaging at high contrast agent concentrations. Results indicate the potential of VTE for imaging with increased SNR at high contrast agent concentrations.
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Affiliation(s)
- A F Stalder
- Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany.
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48
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Three-dimensional contrast-enhanced magnetic-resonance angiography of the renal arteries: interindividual comparison of 0.2 mmol/kg gadobutrol at 1.5 T and 0.1 mmol/kg gadobenate dimeglumine at 3.0 T. Eur Radiol 2008; 18:1260-8. [PMID: 18278504 DOI: 10.1007/s00330-008-0873-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 11/19/2007] [Accepted: 01/09/2008] [Indexed: 10/22/2022]
Abstract
The purpose was to evaluate the image quality of high-spatial resolution MRA of the renal arteries at 1.5 T after contrast-agent injection of 0.2 mmol/kg body weight (BW) in an interindividual comparison to 3.0 T after contrast-agent injection of 0.1 mmol/kg BW contrast agent (CA). After IRB approval and informed consent, 40 consecutive patients (25 men, 15 women; mean age 53.9 years) underwent MRA of the renal arteries either at a 1.5-T MR system with 0.2 mmol/kg BW gadobutrol or at a 3.0-T MR scanner with 0.1 mmol/kg BW gadobenate dimeglumine used as CA in a randomized order. A constant volume of 15 ml of these contrast agents was applied. The spatial resolution of the MRA sequences was 1.0 x 0.8 x 1.0 mm(3) at 1.5 T and 0.9 x 0.8 x 0.9 mm(3) at 3.0 T, which was achieved by using parallel imaging acceleration factors of 2 at 1.5 T and 3 at 3.0 T, respectively. Two radiologists blinded to the administered CA and the field strength assessed the image quality and the venous overlay for the aorta, the proximal and distal renal arteries independently on a four-point Likert-type scale. Phantom measurements were performed for a standardized comparison of SNR at 1.5 T and 3.0 T. There was no significant difference (p > 0.05) between the image quality at 3.0 T with 0.1 mmol/kg BW gadobenate dimeglumine compared to the exams at 1.5 T with 0.2 mmol/kg BW gadobutrol. The median scores were between 3 and 4 (good to excellent vessel visualization) for the aorta (3 at 1.5 T/4 at 3.0 T for reader 1 and 2). For the proximal renal arteries, median scores were 3 for the left and right renal artery at 1.5 T for both readers. At 3.0 T, median scores were 3 (left proximal renal artery) and 4 (right proximal renal artery) for reader 1 and 3 (left/right) for reader 2 at 3.0 T. For the distal renal arteries, median scores were between 2 and 3 at both field strengths (moderate and good) for both readers. The kappa values for both field strengths were comparable and ranged between 0.571 (moderate) for the distal renal arteries and 0.905 (almost perfect) for the proximal renal arteries. In the phantom measurements, a 40% higher SNR was found for the measurements at 3 T with gadobenate dimeglumine. High-spatial resolution renal MRA at 3.0 T with 0.1 mmol/kg BW gadobenate dimeglumine yields at least equal image quality compared with renal MRA at 1.5 T with 0.2 mmol/kg BW gadobutrol.
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Hecht EM, Lee RF, Taouli B, Sodickson DK. Perspectives on body MR imaging at ultrahigh field. Magn Reson Imaging Clin N Am 2008; 15:449-65, viii. [PMID: 17893062 DOI: 10.1016/j.mric.2007.07.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
As investigators consider approaching the challenge of MR imaging at field strengths above 3T, do they follow the same paradigm, and continue to work around the same problems they have encountered thus far at 3T, or do they explore other ways of answering the clinical questions more effectively and more comprehensively? The most immediate problems of imaging at ultrahigh field strength are not unfamiliar, as many of them are still pressing issues at 3T: radiofrequency coils, B1 homogeneity, specific absorption rate, safety, B0 field homogeneity, alterations in tissue contrast, and chemical shift. In this article, these issues are briefly reviewed in terms of how they may affect image quality at field strengths beyond 3T. The authors propose various approaches to overcoming the challenges, and discuss potential applications of ultrahigh field MR imaging as it applies to specific abdominal, pelvic, peripheral vascular, and breast imaging protocols.
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Affiliation(s)
- Elizabeth M Hecht
- Department of Radiology, New York University School of Medicine, 560 First Avenue, New York, NY 10016, USA.
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50
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Abstract
This article illustrates changes in the underlying physics concepts related to increasing the main magnetic field from 1.5T to 3T. The effects of these changes on tissue constants and practical hardware limitations is discussed as they affect scan time, quality, and contrast. Changes in susceptibility artifacts, chemical shift artifacts, and dielectric effects as a result of the increased field strength are also illustrated. Based on these fundamental considerations, an overall understanding of the benefits and constraints of signal-to-noise ratio and contrast-to-noise ratio changes between 1.5T and 3T MR systems is developed.
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Affiliation(s)
- Brian J Soher
- Center for Advanced MR Development, Duke University Medical Center, Box 3808, Durham, NC 27710, USA.
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