scholarly journals Estimating the spatial resolution of in vivo magnetic resonance images using radiofrequency tagging pulses

2007 ◽  
Vol 58 (1) ◽  
pp. 190-199 ◽  
Author(s):  
Wen-Tung Wang ◽  
Peng Hu ◽  
Craig H. Meyer
Keyword(s):  
Magnetic Resonance ◽  
Spatial Resolution ◽  
Magnetic Resonance Images

Does the Modified Arrhenius Model Reliably Predict Area of Tissue Ablation After Magnetic Resonance-Guided Laser Interstitial Thermal Therapy for Pediatric Lesional Epilepsy?

2021 ◽  
Author(s):  
Kelsey D Cobourn ◽  
Imazul Qadir ◽  
Islam Fayed ◽  
Hepzibha Alexander ◽  
Chima O Oluigbo
Keyword(s):  
Magnetic Resonance ◽  
Linear Regression ◽  
Magnetic Resonance Images ◽  
Thermal Therapy ◽  
Invasive Technique ◽  
Hypothalamic Hamartoma ◽  
Arrhenius Model ◽  
Laser Interstitial Thermal Therapy ◽  
Accuracy And Precision

Abstract BACKGROUND Commercial magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) systems utilize a generalized Arrhenius model to estimate the area of tissue damage based on the power and time of ablation. However, the reliability of these estimates in Vivo remains unclear. OBJECTIVE To determine the accuracy and precision of the thermal damage estimate (TDE) calculated by commercially available MRgLITT systems using the generalized Arrhenius model. METHODS A single-center retrospective review of pediatric patients undergoing MRgLITT for lesional epilepsy was performed. The area of each lesion was measured on both TDE and intraoperative postablation, postcontrast T1 magnetic resonance images using ImageJ. Lesions requiring multiple ablations were excluded. The strength of the correlation between TDE and postlesioning measurements was assessed via linear regression. RESULTS A total of 32 lesions were identified in 19 patients. After exclusion, 13 pairs were available for analysis. Linear regression demonstrated a strong correlation between estimated and actual ablation areas (R2 = .97, P < .00001). The TDE underestimated the area of ablation by an average of 3.92% overall (standard error (SE) = 4.57%), but this varied depending on the type of pathologic tissue involved. TDE accuracy and precision were highest in tubers (n = 3), with average underestimation of 2.33% (SE = 0.33%). TDE underestimated the lesioning of the single hypothalamic hamartoma in our series by 52%. In periventricular nodular heterotopias, TDE overestimated ablation areas by an average of 13% (n = 2). CONCLUSION TDE reliability is variably consistent across tissue types, particularly in smaller or periventricular lesions. Further investigation is needed to understand the accuracy of this emerging minimally invasive technique.

The Aqueduct of Sylvius: Applied 3-T Magnetic Resonance Imaging Anatomy and Morphometry With Neuroendoscopic Relevance

2013 ◽  
Vol 73 (2) ◽  
pp. ons132-ons140 ◽  
Author(s):  
Tomasz Matys ◽  
Avril Horsburgh ◽  
Ramez W. Kirollos ◽  
Tarik F. Massoud
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Pearson Correlation ◽  
Third Ventricle ◽  
Magnetic Resonance Images ◽  
Resonance Imaging ◽  
The Third ◽  
Aqueduct Of Sylvius ◽  
Pars Anterior

Abstract BACKGROUND: The aqueduct of Sylvius (AqSylv) is a structure of increasing importance in neuroendoscopic procedures. However, there is currently no clear and adequate description of the normal anatomy of the AqSylv. OBJECTIVE: To study in detail hitherto unavailable normal magnetic resonance imaging morphometry and anatomic variants of the AqSylv. METHODS: We retrospectively studied normal midsagittal T1-weighted 3-T magnetic resonance images in 100 patients. We measured widths of the AqSylv pars anterior, ampulla, and pars posterior; its narrowest point; and its length. We recorded angulation of the AqSylv relative to the third ventricle as multiple deviations of the long axis of the AqSylv from the Talairach bicommissural line. We statistically determined age- and sex-related changes in AqSylv morphometry using the Pearson correlation coefficient. We measured angulation of the AqSylv relative to the fourth ventricle and correlated this to the cervicomedullary angle (a surrogate for head position). RESULTS: Patients were 13 to 83 years of age (45% male, 55% female). Mean morphometrics were as follows: pars anterior width, 1.1 mm; ampulla width, 1.2 mm; pars posterior width, 1.4 mm; length, 14.1 mm; narrowest point, 0.9 mm; and angulation in relation to the third and fourth ventricles, 26° and 18°, respectively. Age correlated positively with width and negatively with length of the AqSylv. There was no correlation between AqSylv alignment relative to the foramen magnum and the cervicomedullary angle. CONCLUSION: Normative dimensions of the AqSylv in vivo are at variance with published cadaveric morphometrics. The AqSylv widens and shortens with cerebral involution. Awareness of these normal morphometrics is highly useful when stent placement is an option during aqueductoplasty. Reported data are valuable in guiding neuroendoscopic management of hydrocephalus and aqueductal stenosis.

scholarly journals The effect of varying spectral resolution on the quality of high spectral and spatial resolution magnetic resonance images of the breast

2003 ◽  
Vol 18 (4) ◽  
pp. 442-448 ◽  
Author(s):  
Milica Medved ◽  
Weiliang Du ◽  
Marta A. Zamora ◽  
Xiaobing Fan ◽  
Olufunmilayo I. Olopade ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Spatial Resolution ◽  
Spectral Resolution ◽  
Magnetic Resonance Images

scholarly journals Correlation of tissue drug concentrations with in vivo magnetic resonance images of polymer drug depot around arteriovenous graft

2010 ◽  
Vol 146 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Shawn C. Owen ◽  
Huan Li ◽  
William G. Sanders ◽  
Alfred K. Cheung ◽  
Christi M. Terry
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Images ◽  
Arteriovenous Graft ◽  
Drug Concentrations

scholarly journals Influence of partial k-space filling on the quality of magnetic resonance images

2016 ◽  
Vol 49 (3) ◽  
pp. 158-164
Author(s):  
Tiago da Silva Jornada ◽  
Camila Hitomi Murata ◽  
Regina Bitelli Medeiros
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Magnetic Resonance Images ◽  
Resonance Imaging ◽  
Signal To Noise ◽  
T1 And T2 ◽  
Space Acquisition ◽  
Magnetic Resonance Imaging Equipment

Abstract Objective: To study the influence that the scan percentage tool used in partial k-space acquisition has on the quality of images obtained with magnetic resonance imaging equipment. Materials and Methods: A Philips 1.5 T magnetic resonance imaging scanner was used in order to obtain phantom images for quality control tests and images of the knee of an adult male. Results: There were no significant variations in the uniformity and signal-to-noise ratios with the phantom images. However, analysis of the high-contrast spatial resolution revealed significant degradation when scan percentages of 70% and 85% were used in the acquisition of T1- and T2-weighted images, respectively. There was significant degradation when a scan percentage of 25% was used in T1- and T2-weighted in vivo images (p ≤ 0.01 for both). Conclusion: The use of tools that limit the k-space is not recommended without knowledge of their effect on image quality.

Magnetic Resonance Images Lipid, Fibrous, Calcified, Hemorrhagic, and Thrombotic Components of Human Atherosclerosis In Vivo

Circulation ◽  
1996 ◽  
Vol 94 (5) ◽  
pp. 932-938 ◽  
Author(s):  
Jean-Franc¸ois Toussaint ◽  
Glenn M. LaMuraglia ◽  
James F. Southern ◽  
Valentin Fuster ◽  
Howard L. Kantor
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Images ◽  
Human Atherosclerosis
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