• Investigative Magnetic Resonance Imaging
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• v.17 no.2
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• pp.91-100
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• 2013

Purpose : To evaluate the usefulness of cervicothoracic spine sagittal T2-weighted images (CT SAG T2WIs) included in routine lumbar spine MRI. Materials and Methods: Institutional review board approval was obtained and informed consents were waived for this retrospective study. The study group comprised 2,113 patients who underwent lumbar spine MRI from January 2005 to December 2005. CT SAG T2WIs were added in the routine lumbar spine MRIs. Radiologic reports were reviewed retrospectively for pathologic lesions on CT SAG T2WIs by one radiologist. Information of additional cervical or thoracic spine MRI and/or CT for further evaluation of positive findings on CT SAG T2WIs and their treatment were collected by retrospectively reviewing medical records. Results: The CT SAG T2WIs revealed 142 pathologic lesions in 139 (6.58%) of the 2,113 patients. They were easily obtained without positional change in a scan time of less than 2 minutes. Additional cervical or thoracic spine MRI and/or CT for positive findings on CT SAG T2WIs were performed in 13 patients. Seven patients underwent surgical treatment. Conclusion: CT SAG T2WIs included in routine lumbar spine MRI were useful in finding the pathologic lesions in cervicothoracic spine for the patients who assumed to have lesions in lumbar spine.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.5
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• pp.488-491
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• 2005

A 3-year-old female, 5kg, Shih-tzu developed an acute onset of depression, disorientation, hypersalivation, nystagmus after falling down 2 meter height place. In plain skull radiography, there was fracture line in the frontal and parietal bones and next day magnetic resonance imaging examination was performed. Magnetic resonance imaging of the brain was performed with 3.0 Tesla unit. Under general anesthesia, the dog was placed in prone with its head positioned in a birdcage coil. Transverse, sagittal and coronal fast spin echo images of the brain were obtained with the following pulse sequences: T1 weighted images (TR = 560 ms and TE = 18.6 ms) and T2 weighted images (TR = 3500 ms and TE = 80 ms). Magnetic resonance imaging showed epidural hematoma in the left frontal area resulting in compression of the adjacent brain parenchyma. Left lateral ventricle was compressed secondarily and the longitudinal fissure shifted to the right, representing mass effect. The lesion was iso-to slightly hyperintense on T1 weighted image and iso-slightly hypointense signal on T2 weighted image. At necropsy, there was a skull fracture and epidural hematoma in the left frontal area. Magnetic resonance imaging of epidural hematoma is reviewed.

• Journal of Korean Neurosurgical Society
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• v.38 no.1
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• pp.71-73
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• 2005

A case of intramedullary spinal cord lipoma is presented. A one month-old male infant presented with irritability and weakness on his upper extremities. A magnetic resonance[MR] image of the cervical spine demonstrated a well defined, high signal intensity lesion on both T1 and T2-weighted MR images and suppression on the fat saturation sequence. The tumor mass extended from the foramen magnum to T2 vertebra level. Ventral displacement of the spinal cord with kinking of the cervico-medullary junction was evident on the T2-weighted sagittal image. Partial resection of the tumor mass through laminoplastic laminotomy from C1 to T2 resulted in improved motor weakness on his upper extremities.

• Imaging Science in Dentistry
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• v.52 no.4
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• pp.393-398
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• 2022

Purpose: This study proposed a generative adversarial network (GAN) model for T2-weighted image (WI) synthesis from proton density (PD)-WI in a temporomandibular joint(TMJ) magnetic resonance imaging (MRI) protocol. Materials and Methods: From January to November 2019, MRI scans for TMJ were reviewed and 308 imaging sets were collected. For training, 277 pairs of PD- and T2-WI sagittal TMJ images were used. Transfer learning of the pix2pix GAN model was utilized to generate T2-WI from PD-WI. Model performance was evaluated with the structural similarity index map (SSIM) and peak signal-to-noise ratio (PSNR) indices for 31 predicted T2-WI (pT2). The disc position was clinically diagnosed as anterior disc displacement with or without reduction, and joint effusion as present or absent. The true T2-WI-based diagnosis was regarded as the gold standard, to which pT2-based diagnoses were compared using Cohen's ĸ coefficient. Results: The mean SSIM and PSNR values were 0.4781(±0.0522) and 21.30(±1.51) dB, respectively. The pT2 protocol showed almost perfect agreement(ĸ=0.81) with the gold standard for disc position. The number of discordant cases was higher for normal disc position (17%) than for anterior displacement with reduction (2%) or without reduction (10%). The effusion diagnosis also showed almost perfect agreement(ĸ=0.88), with higher concordance for the presence (85%) than for the absence (77%) of effusion. Conclusion: The application of pT2 images for a TMJ MRI protocol useful for diagnosis, although the image quality of pT2 was not fully satisfactory. Further research is expected to enhance pT2 quality.

• Imaging Science in Dentistry
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• v.50 no.2
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• pp.93-98
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• 2020

Purpose: Little is known regarding the accuracy of clinical magnetic resonance imaging (MRI) protocols with acceptable scan times in sinus graft assessment. The aim of this study was to evaluate the correlations between MRI and cone-beam computed tomographic (CBCT) measurements of maxillary sinus grafts using 2 different clinical MRI imaging protocols. Materials and Methods: A total of 15 patients who underwent unilateral sinus lift surgery with biphasic calcium phosphate were included in this study. CBCT, T1-weighted MRI, and T2-weighted MRI scans were taken 6 months after sinus lift surgery. Linear measurements of the maximum height and buccolingual width in coronal images, as well as the maximum anteroposterior depth in sagittal images, were performed by 2 trained observers using CBCT and MRI Digital Imaging and Communication in Medicine files. Micro-computed tomography (micro-CT) was also performed to confirm the presence of bone tissue in the grafted area. Correlations between MRI and CBCT measurements were assessed with the Pearson test. Results: Significant correlations between CBCT and MRI were found for sinus graft height (T1-weighted, r=0.711 and P<0.05; T2-weighted, r=0.713 and P<0.05), buccolingual width (T1-weighted, r=0.892 and P<0.05; T2-weighted, r=0.956 and P<0.05), and anteroposterior depth (T1-weighted, r=0.731 and P<0.05; T2-weighted, r=0.873 and P<0.05). The presence of bone tissue in the grafted areas was confirmed via micro-CT. Conclusion: Both MRI pulse sequences tested can be used for sinus graft measurements, as strong correlations with CBCT were found. However, correlations between T2-weighted MRI and CBCT were slightly higher than those between T1-weighted MRI and CBCT.

• Imaging Science in Dentistry
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• v.43 no.4
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• pp.245-251
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• 2013

Purpose: This study was performed to evaluate the relationship between anterior disc displacement and effusion in temporomandibular disorder (TMD) patients using magnetic resonance imaging (MRI). Materials and Methods: The study subjects included 253 TMD patients. MRI examinations were performed using a 1.5 T MRI scanner. T1- and T2-weighted images with para-sagittal and para-coronal images were obtained. According to the MRI findings, temporomandibular joint (TMJ) disc positions were divided into 3 subgroups: normal, anterior disc displacement with reduction (DWR), and anterior disc displacement without reduction (DWOR). The cases of effusion were divided into 4 groups: normal, mild (E1), moderate (E2), and marked effusion (E3). Statistical analysis was made by the Fisher's exact test using SPSS (version 12.0, SPSS Inc., Chicago, IL, USA). Results: The subjects consisted of 62 males and 191 females with a mean age of 28.5 years. Of the 253 patients, T1- and T2-weighted images revealed 34 (13.4%) normal, DWR in 103 (40.7%), and DWOR in 116 (45.9%) on the right side and 37 (14.6%) normal, DWR in 94 (37.2%), and DWOR in 122 (48.2%) joints on the left side. Also, T2-images revealed 82 (32.4%) normal, 78 (30.8%) E1, 51 (20.2%) E2, and 42 (16.6%) E3 joints on the right side and 79 (31.2%) normal, 85 (33.6%) E1, 57 (22.5%) E2, and 32 (12.7%) E3 on the left side. There was no difference between the right and left side. Conclusion: Anterior disc displacement was not related to the MRI findings of effusion in TMD patients (P>0.05).

• Korean Journal of Radiology
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• v.2 no.2
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• pp.63-67
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• 2001

Objective: Atrophy and a high T2 signal of the hippocampus are known to be the principal MR imaging findings of hippocampal sclerosis. The purpose of this study was to determine whether or not individual MRI findings correlate with surgical outcome in patients with this condition. Materials and Methods: Preoperative MR imaging findings in 57 consecutive patients with pathologically-proven hippocampal sclerosis who underwent anterior temporal lobectomy and were followed-up for 24 months or more were retrospectively reviewed, and the results were compared with the postsurgical outcome (Engel classification). The MR images included routine sagittal T1-weighted and axial T2-weighted spin-echo images, and oblique coronal T1-weighted 3D gradient-echo and T2-weighted 2D fast spin-echo images obtained on either a 1.5 T or 1.0 T unit. The images were visually evaluated by two neuroradiologists blinded to the outcome; their focus was the presence or absence of atrophy and a high T2 hippocampal signal. Results: Hippocampal atrophy was seen in 96% of cases (55/57) [100% (53/53) of the good outcome group (Engel class I and II), and 50% (2/4) of the poor outcome group (class III and IV)]. A high T2 hippocampal signal was seen in 61% of cases (35/57) [62% (33/53) of the good outcome group and 50% (2/4) of the poor outcome group]. All 35 patients with a high T2 signal had hippocampal atrophy. 'Normal' hippocampus, as revealed by MR imaging, occurred in 4% of patients (2/57), both of whom showed a poor outcome (Engel class III). The presence or absence of hippocampal atrophy correlated well with surgical outcome (p<0.01). High T2 signal intensity did not, however, significantly correlate with surgical outcome (p>0.05). Conclusion: Compared with a high T2 hippocampal signal, hippocampal atrophy is more common and correlates better with surgical outcome. For the prediction of this, it thus appears to be the more useful indicator.

• Journal of radiological science and technology
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• v.33 no.1
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• pp.45-50
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• 2010

In this study, we compared the clinical usefulness of SPAIR (Spectral Adiabatic Inversion Recovery) and STIR (Short TI Inversion Recovery) to evaluate the fat tissues precisely. The images of brain axial (n = 20), lumber spine sagittal (n = 20), hip joint coronal (n = 17) and knee joint (n = 25) were obtained by turbo spin echo T2 weighted method on 3T magnetic resonance image. The signal intensity (SI) values were measured using region of interest in fat, muscle tissue, and background noise. The inhomogeneity values were measured using the standard deviation (SD) value divided by the mean values. SD signifies the amount of error which is similar to the imaging heterogeneity. In brain axial images, the SPAIR showed more superior SI and inhomogeneity results than the STIR. In spine, hip and knee images, STIR showed more excellent SI results, but poor inhomogeneity than the SPAIR.

• Journal of Digital Contents Society
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• v.11 no.4
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• pp.425-431
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• 2010

This study explored the effects and the effectiveness of the new method of 3D FIESTA by making quantitative comparison with the conventional 3D FSE method which is frequently employed on patients with sudden hearing loss in clinical settings. For this study, 3D FSE images acquired with 3.0T MR scanner and T2-weighted axial plane 3D FIESTA images were respectively taken from 40 patients diagnosed with Sensorineural Hearing Loss (SSHL). When obtaining those images, sagittal reconstructions oriented perpendicular to the nerve were performed in order to get sagittal images of both right and left internal auditory canal. The findings showed that both SNR and CNR were higher among the group to whom the 3D FIESTA method was applied than the group to whom the conventional 3D FSE method was applied.

• Journal of Veterinary Clinics
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• v.23 no.3
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• pp.366-370
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• 2006

Arachnoid cysts are intra-arachnoid collections of cerebrospinal fluid. They may cause neurological deficit through expansion that can compress normal neural tissue and obstruct cerebrospinal fluid flow. Intracranial arachnoid cysts were found in 4 patients aged 10 months to 20 months(mean age 15 months). The presenting symptoms included circling(dog 2,3), seizure(dog 1), progressive weakness(dog 1,2,3), increasing scoliosis(dog 3), worsening spasticity(dog 3), and salivation(dog 3). One patient showed no symptoms from the intracranial arachnoid cyst. There were no significant findings in complete blood count and serum chemistry. Computed tomography(CT) with/without magnetic resonance imaging(MRI) scans were performed in these cases. Hypodense intracranial arachnoid cyst was observed on CT images in dog 4. Sagittal T1-weighted(T1W) and T2-weighted(T2W) images and transverse T1W and T2W images revealed a intracranial arachnoid cysts with syringohydromyelia(dog 3) and hydrocephalus(dog 3,4) in the brain. Clinical signs of three cases were improved by medication.