Structural Abnormalities in Pediatric Moyamoya Disease Revealed by Clinical Magnetic Resonance Imaging, Regionally Distributed Relative Signal Intensities and Volumes

Author(s):  
Prahar Ijner ◽  
Grace Tompkins ◽  
Tadashi Shiohama ◽  
Emi Takahashi ◽  
Jacob Levman
2016 ◽  
Vol 16 (6) ◽  
pp. 294-299 ◽  
Author(s):  
S. Solis-Najera ◽  
F. Vazquez ◽  
R. Hernandez ◽  
O. Marrufo ◽  
A.O. Rodriguez

Abstract A surface radio frequency coil was developed for small animal image acquisition in a pre-clinical magnetic resonance imaging system at 7 T. A flexible coil composed of two circular loops was developed to closely cover the object to be imaged. Electromagnetic numerical simulations were performed to evaluate its performance before the coil construction. An analytical expression of the mutual inductance for the two circular loops as a function of the separation between them was derived and used to validate the simulations. The RF coil is composed of two circular loops with a 5 cm external diameter and was tuned to 300 MHz and 50 Ohms matched. The angle between the loops was varied and the Q factor was obtained from the S11 simulations for each angle. B1 homogeneity was also evaluated using the electromagnetic simulations. The coil prototype was designed and built considering the numerical simulation results. To show the feasibility of the coil and its performance, saline-solution phantom images were acquired. A correlation of the simulations and imaging experimental results was conducted showing a concordance of 0.88 for the B1 field. The best coil performance was obtained at the 90° aperture angle. A more realistic phantom was also built using a formaldehyde-fixed rat phantom for ex vivo imaging experiments. All images showed a good image quality revealing clearly defined anatomical details of an ex vivo rat.


Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Lian Duan ◽  
Wei-Hai Xu ◽  
Cong Han

Introduction: The diagnosis in the patients with angiographic moyamoya findings and atherogenic risk factors is challenging. In this study, we try to incorporate high-resolution magnetic resonance imaging (HRMRI) into the diagnostic process of intracranial atherosclerosis associated moyamoya syndrome. Methods: From March 2013 to March 2014, HRMRI was consecutively performed on adult patients with angiographic moyamoya. The patients were classified as moyamoya - plaques (MMD-P) if a plaque could be identified or as moyamoya - no plaques (MMD-NP) if a plaque could not be identified. The angiography, HRMRI findings and atherogenic risk factors of these patients were analyzed. Results: Fifty-one patients (mean age 39±9, 20 males) were enrolled. On traditional angiography, probable intracranial atherosclerosis was identified in 5 patients, no definite diagnosis in 12 patients, and moyamoya disease in 34 patients. On HRMRI, 15 out of 32 patients with risk factors and 4 out of 19 patients without risk factors were found to have plaques and were diagnosed as MMD-P, while the other 32 patients were diagnosed as MMD-NP. The MMD-P patients were more likely to be older and male and were less likely to have cerebral hemorrhage and a history of disease progression. Conclusions: Our study suggests that HRMRI can help diagnose intracranial atherosclerosis more accurately in moyamoya disease patients with atherogenic risk factors. The distinct clinical features between MMD-P and MMD-NP patients suggest different underlying pathophysiology and therefore potentially different treatment strategies.


2014 ◽  
Vol 18 (1) ◽  
Author(s):  
Nasreen Mahomed ◽  
Evance Chisama ◽  
Sanjay Prabhu

The ivy sign refers to diffuse bilateral leptomeningeal enhancement on post- contrastT1-weighted magnetic resonance imaging (MRI) and increased signal intensity in bilateralsubarachnoid spaces and perivascular spaces on T2-weighted fluid attenuation inversionrecovery (FLAIR) MRI sequences in patients with moyamoya disease.


2015 ◽  
Vol 128 (23) ◽  
pp. 3231-3237 ◽  
Author(s):  
Le-Bao Yu ◽  
Qian Zhang ◽  
Zhi-Yong Shi ◽  
Ming-Qiu Wang ◽  
Dong Zhang

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