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

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 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.

Intertester Reliability and Validity of Motion Assessments During Lumbar Spine Accessory Motion Testing

2008 ◽  
Vol 88 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Rob Landel ◽  
Kornelia Kulig ◽  
Michael Fredericson ◽  
Bernard Li ◽  
Christopher M Powers
Keyword(s):  
Lumbar Spine ◽  
Magnetic Resonance ◽  
Sagittal Plane ◽  
Magnetic Resonance Images ◽  
Segmental Motion ◽  
Segmental Mobility ◽  
Spine Motion ◽  
Mobile Segment ◽  
Good Agreement

Background and PurposePosterior-anterior (PA) assessment of the lumbar spine correlates with radiographic signs of instability and can guide treatment choices, yet studies of the validity of lumbar PA assessments have not been conducted in vivo. The purposes of this study were to determine the intertester reliability of the PA examination in assessing intersegmental lumbar spine motion and to evaluate the validity of this procedure in vivo with dynamic magnetic resonance imaging (MRI).SubjectsTwenty-nine subjects with central lumbar pain participated in this study.MethodsTwo physical therapists independently identified each subject's most and least mobile lumbar segments using the PA procedure. Midsagittal lumbar images were obtained simultaneously during one examiner's assessment. Lumbar segmental mobility was quantified from magnetic resonance images as the change in the intervertebral angle between the resting position and the end range of the PA force application. For each vertebral level tested, maximal sagittal-plane segmental motion was determined.ResultsThe intertester reliability for identifying the least mobile segment was good (agreement=82.8%, kappa=.71, 95% confidence interval [CI]=.48 to .94), but it was poor for identifying the most mobile segment (kappa=.29, 95% CI=−.13 to .71), despite good agreement (79.3%). The level of agreement between the PA assessments and intervertebral motion measured by MRI was poor (kappa=.04, 95% CI=−.16 to .24, and kappa=.00, 95% CI=−.09 to .08, for the least and most mobile segments, respectively).Discussion and ConclusionDespite good intertester reliability for identifying the least mobile segment, PA assessments of lumbar segmental mobility did not agree with sagittal-plane motion measured by dynamic MRI. This finding calls into question the validity of the PA procedure for assessing intervertebral lumbar spine motion.

scholarly journals Evaluation of different magnetic resonance imaging contrast materials to be used as dummy markers in image-guided brachytherapy for gynecologic malignancies

2016 ◽  
Vol 49 (3) ◽  
pp. 165-169
Author(s):  
Camila Pessoa Sales ◽  
Heloisa de Andrade Carvalho ◽  
Khallil Chaim Taverna ◽  
Bruno Fraccini Pastorello ◽  
Rodrigo Augusto Rubo ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Water Solution ◽  
Contrast Material ◽  
Magnetic Resonance Images ◽  
Resonance Imaging ◽  
Dwell Position ◽  
Weighted Sequences

Abstract Objective: To identify a contrast material that could be used as a dummy marker for magnetic resonance imaging. Materials and Methods: Magnetic resonance images were acquired with six different catheter-filling materials-water, glucose 50%, saline, olive oil, glycerin, and copper sulfate (CuSO4) water solution (2.08 g/L)-inserted into compatible computed tomography/magnetic resonance imaging ring applicators placed in a phantom made of gelatin and CuSO4. The best contrast media were tested in four patients with the applicators in place. Results: In T2-weighted sequences, the best contrast was achieved with the CuSO4-filled catheters, followed by saline- and glycerin-filled catheters, which presented poor visualization. In addition (also in T2-weighted sequences), CuSO4 presented better contrast when tested in the phantom than when tested in the patients, in which it provided some contrast but with poor identification of the first dwell position, mainly in the ring. Conclusion: We found CuSO4 to be the best solution for visualization of the applicator channels, mainly in T2-weighted images in vitro, although the materials tested presented low signal intensity in the images obtained in vivo, as well as poor precision in determining the first dwell position.

Stress Analysis of Carotid Atheroma in Transient Ischemic Attack Patients

2009 ◽  
Author(s):  
Hao Gao ◽  
Quan Long ◽  
Martin Graves ◽  
Jonathan H. Gillard ◽  
Zhi-Yong Li
Keyword(s):  
Magnetic Resonance ◽  
Stress Analysis ◽  
Atherosclerotic Plaque ◽  
Transient Ischemic Attack ◽  
Plaque Rupture ◽  
Magnetic Resonance Images ◽  
Patient Specific ◽  
Critical Information ◽  
Ischemic Attack

Rupture of atherosclerotic plaque is a major cause of mortality. Plaque stress analysis, based on patient-specific multi-sequence in vivo magnetic resonance images (MRI), can provide critical information for the understanding of plaque rupture and could eventually lead to plaque rupture prediction [1].

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