scholarly journals Identification of Laminar Composition in Cerebral Cortex Using Low-Resolution Magnetic Resonance Images and Trust Region Optimization Algorithm

Diagnostics ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 24
Author(s):  
Jakub Jamárik ◽  
Lubomír Vojtíšek ◽  
Vendula Churová ◽  
Tomáš Kašpárek ◽  
Daniel Schwarz
Keyword(s):  
Magnetic Resonance ◽  
Relaxation Times ◽  
Trust Region ◽  
Magnetic Resonance Images ◽  
Estimation Accuracy ◽  
Percentage Error ◽  
Planar Imaging ◽  
T1 Relaxation ◽  
Starting Point

Pathological changes in the cortical lamina can cause several mental disorders. Visualization of these changes in vivo would enhance their diagnostics. Recently a framework for visualizing cortical structures by magnetic resonance imaging (MRI) has emerged. This is based on mathematical modeling of multi-component T1 relaxation at the sub-voxel level. This work proposes a new approach for their estimation. The approach is validated using simulated data. Sixteen MRI experiments were carried out on healthy volunteers. A modified echo-planar imaging (EPI) sequence was used to acquire 105 individual volumes. Data simulating the images were created, serving as the ground truth. The model was fitted to the data using a modified Trust Region algorithm. In single voxel experiments, the estimation accuracy of the T1 relaxation times depended on the number of optimization starting points and the level of noise. A single starting point resulted in a mean percentage error (MPE) of 6.1%, while 100 starting points resulted in a perfect fit. The MPE was <5% for the signal-to-noise ratio (SNR) ≥ 38 dB. Concerning multiple voxel experiments, the MPE was <5% for all components. Estimation of T1 relaxation times can be achieved using the modified algorithm with MPE < 5%.

An emerging technology: Nuclear magnetic resonance microscopy

1988 ◽  
Vol 46 ◽  
pp. 1000-1001
Author(s):  
M.J. Hennessy ◽  
E. Kwok
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Basic Research ◽  
Local Environment ◽  
Magnetic Resonance Images ◽  
Nmr Microscopy ◽  
Mri Scans ◽  
Temperature Relaxation ◽  
Nuclear Magnetic

Much progress in nuclear magnetic resonance microscope has been made in the last few years as a result of improved instrumentation and techniques being made available through basic research in magnetic resonance imaging (MRI) technologies for medicine. Nuclear magnetic resonance (NMR) was first observed in the hydrogen nucleus in water by Bloch, Purcell and Pound over 40 years ago. Today, in medicine, virtually all commercial MRI scans are made of water bound in tissue. This is also true for NMR microscopy, which has focussed mainly on biological applications. The reason water is the favored molecule for NMR is because water is,the most abundant molecule in biology. It is also the most NMR sensitive having the largest nuclear magnetic moment and having reasonable room temperature relaxation times (from 10 ms to 3 sec). The contrast seen in magnetic resonance images is due mostly to distribution of water relaxation times in sample which are extremely sensitive to the local environment.

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 &lt; .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.

Magnetic resonance relaxometry in monozygotic twins discordant and concordant for schizophrenia

2005 ◽  
Vol 20 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Filip Spaniel ◽  
Vit Herynek ◽  
Tomas Hajek ◽  
Monika Dezortova ◽  
Jiri Horacek ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Globus Pallidus ◽  
Relaxation Times ◽  
Monozygotic Twins ◽  
T2 Relaxation ◽  
T1 Relaxation ◽  
Significant Prolongation ◽  
Healthy Control ◽  
Genetic Loading ◽  
Mz Twins

AbstractT1 and T2 relaxation times were examined in four pairs of monozygotic (MZ) twins discordant and concordant for schizophrenia with low and high genetic loading for the illness and five healthy control MZ twin pairs. Patients with schizophrenia (n = 11) showed significant prolongation in T1 relaxation times in the globus pallidus (GP) bilaterally (P < 0.005, Bonferroni corrected) when compared to 14 healthy MZ twins.

Magnetic resonance imaging T1 relaxation times for the liver, pancreas and spleen in healthy children at 1.5 and 3 tesla

2019 ◽  
Vol 49 (8) ◽  
pp. 1018-1024 ◽  
Author(s):  
Leah A. Gilligan ◽  
Jonathan R. Dillman ◽  
Jean A. Tkach ◽  
Stavra A. Xanthakos ◽  
Jacqueline K. Gill ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
3 Tesla ◽  
Healthy Children ◽  
Resonance Imaging ◽  
T1 Relaxation

Gadolinium-DTPA Enhancement of Experimental Soft Tissue Carcinoma and Hemorrhage in Magnetic Resonance Imaging

1987 ◽  
Vol 28 (1) ◽  
pp. 75-78 ◽  
Author(s):  
H. Pettersson ◽  
N. Ackerman ◽  
J. Kaude ◽  
R. E. Googe ◽  
A. A. Mancuso ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Body Weight ◽  
Magnetic Resonance ◽  
Tumor Tissue ◽  
Soft Tissues ◽  
Relaxation Times ◽  
Resonance Imaging ◽  
Benign Lesions ◽  
Gadolinium Dtpa ◽  
T1 Relaxation

An experimental series in the rabbit was performed to test gadolinium-DTPA (Gd-DTPA) enhancement of VX-2 carcinoma and hemorrhages induced in the soft tissues. The recognition of both malignant and benign lesions was greatly facilitated on T1 weighted images after intravenous administration of 0.3 mmol Gd-DTPA/kg body weight because of reduced T1 relaxation times. Gd-DTPA enhancement reached its maximum after 10–15 minutes and was most apparent in tumor tissue, connective tissue surrounding the tumor and in the area of fresh hemorrhage.

Nuclear magnetic resonance imaging and spectroscopy in experimental brain edema in a rat model

1986 ◽  
Vol 64 (5) ◽  
pp. 795-802 ◽  
Author(s):  
Joshua B. Bederson ◽  
Henry M. Bartkowski ◽  
Kirkland Moon ◽  
Meredith Halks-Miller ◽  
Merry C. Nishimura ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Water Content ◽  
Cerebral Blood Volume ◽  
Relaxation Times ◽  
Nmr Relaxation ◽  
Resonance Imaging ◽  
Content Type ◽  
Nmr Relaxation Times

✓ Many aspects of the use of high-resolution nuclear magnetic resonance (NMR) imaging in the examination of brain edema have not been fully explored. These include the quantitation of edema fluid, the ability to distinguish between various types of edema, and the extent to which tissue changes other than a change in water content can affect NMR relaxation times. The authors have compared NMR relaxation times obtained by both in vivo magnetic resonance imaging (MRI) and in vitro NMR spectroscopy of brain-tissue samples from young adult rats with cold lesions, fluid-percussion injury, hypoxic-ischemic injury, bacterial cerebritis, and cerebral tumor. Changes in relaxation times were compared with changes in brain water content, cerebral blood volume, and the results of histological examination. In general, both in vivo and in vitro longitudinal relaxation times (T1) and transverse relaxation times (T2) were prolonged in the injured hemispheres of all experimental groups. Water content of tissue from the injured hemispheres was increased in all groups. A linear correlation between T2 (but not T1) and water content was found. Changes in the values of T1 and T2 could be used to distinguish tumor from cold-injured tissue. Cerebral blood volume was reduced in the injured hemispheres and correlated inversely with prolongation of T1 and T2. The results of this study suggest that, in a clinical setting, prolongation of T2 is a better indicator of increased water content than prolongation of T1, yet quantitation of cerebral edema based solely upon prolongation of in vivo or in vitro T1 and T2 should be undertaken with caution.

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.

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