• Korean Journal of Radiology
• /
• v.20 no.5
• /
• pp.823-829
• /
• 2019

Objective: To summarize the high-resolution computed tomography (HRCT) and magnetic resonance imaging (HRMRI) features of duplicated internal auditory canals (DIACs). Materials and Methods: Ear HRCT data of 64813 patients with sensorineural hearing loss (SNHL), obtained between August 2009 and November 2017, were reviewed. Among these patients, 12 (13 ears) were found to have DIACs, 9 of whom underwent HRMRI. Their images were evaluated by two otoradiologists. Results: The rate of occurrence of DIAC among SNHL patients was 0.019% (12/64813). The internal auditory canals of 13 ears were divided into double canals by complete (n = 6) and incomplete (n = 7) bony septa, with varied orientations ranging from horizontal to approximately vertical. All of the anterosuperior canals extended into the facial nerve (FN) canal, except for 1, which also extended to the vestibule. The posteroinferior canals ended in the cochlea and vestibule, except for 2, which also connected to the FN canals. Magnetic resonance images revealed that 77.8% (7/9) and 22.2% (2/9) of vestibulocochlear nerves (VCNs) were aplastic and hypoplastic, respectively. Furthermore, 88.9% (8/9) of FNs were normal, except for 1, which was hypoplastic. All of the affected ears also had other ear anomalies: a narrow, bony cochlear nerve canal was the most common other anomaly, accounting for 92.3% (12/13). Malformations of other systems were not found. Conclusion: Double-canal appearance is a characteristic finding of DIAC on HRCT, and it is usually accompanied by other ear anomalies. The VCN usually appears aplastic, with a normal FN, on HRMRI.

• Journal of Korean Neurosurgical Society
• /
• v.29 no.10
• /
• pp.1316-1321
• /
• 2000

Objectives : The authors analyzed the surgical series of Cushing's disease to evaluate the proper treatment policy and to verify the possible prognostic factors. Material and Methods : Of 50 patients diagnosed as Cushing's disease and operated at Department of Neurosurgery of our institute between 1988 and 1999, 48 patients with available medical records were analyzed retrospectively. Mean follow-up period was 48 months(3 to 109 months). Preoperative diagnosis was made after evaluating the patients with multiple-stage endocrinological studies and 31 selective patients were evaluated with inferior petrosal sinus sampling(IPSS). Magnetic resonance imaging(MRI) and/or high resolution computerized tomography(CT) was done in all patients. A total of 51 transsphenoidal adenomectomy(TSA) were performed including 3 revision for initial surgical failure cases. Remission was decided on the basis of both endocrinological criteria and clinical status. Radiation and/or ketoconazole therapy were applied to failed cases. For the verification of prognostic factors, the authors evaluated the statistical significance of multiple variables over remission rate by chi-square test. Result : Sensitivity of IPSS for central localization was 93.5% which was better than that of MRI(87.5%). But for lateralization, it was 72.4% for IPSS versus MRI 90.5%. Success rate of TSA was 82%(42/51) and recurrence rate was 9%(4/48). When including adjuvant treatments for surgically failed cases, overall success rate was 89.6% and all of 3 reoperated cases(TSA) due to recurrence were successful. Significant complication occurred in 7.8%(4/51) after TSA including hypopituitarism, diabetes insipidus, and visual loss. Non-existence of tumor in MRI and prolonged symptom duration(>3 years) were significant prognostic factors. Conclusion : TSA can be considered as initial treatment for Cushing's disease. In surgically failed cases, multiple treatment modality may improve the overall outcome and repeated TSA for recurrent cases seem to provide similar success.

• Journal of Magnetics
• /
• v.19 no.3
• /
• pp.248-254
• /
• 2014

The purpose of this study is to figure out how uptake counts of technetium ($^{99m}Tc$) among radioisotopes in the human body are affected if computed tomography (CT), magnetic resonance imaging (MRI) and isotope examination are performed consecutively. $^{99m}Tc$ isotope material, iodinated contrast media for CT and paramagnetic contrast media for magnetic resonance (MR) were used as experimental materials. First, $^{99m}Tc$ was added to 4 cc normal saline in a test tube. Then, 2 cc of CT contrast media such as $Iopamidol^{(R)}$ and $Dotarem^{(R)}$ were diluted with 2 cc normal saline, and 2cc of MRI contrast media such as $Primovist^{(R)}$ and $Gadovist^{(R)}$ were diluted with 2 cc normal saline. Each distributed contrast media was a total of 4 cc and included 10m Ci of $^{99m}Tc$. A gamma camera, a LEHR (Low energy high resolution) collimator and a pin-hole collimator were used for image acquisition. Image acquisition was repeated a total of 6 times and 120 frames were obtained and uptake counts of $^{99m}Tc$ were measured (from this procedure). In this study, as a result of measuring the uptake counts of $^{99m}Tc$ using the LEHR collimator, the uptake counts were less measured in all contrast media than normal saline as a reference. In particular, the lowest uptake counts were measured when $Gadovist^{(R)}$, contrast media for MRI, was used. However, the result of measuring the uptake counts of $^{99m}Tc$ using the pin-hole collimator showed higher uptake counts in all contrast media, except for $Iopamidol^{(R)}$, than normal saline as a reference. The highest uptake counts were measured particularly when $Primovist^{(R)}$, contrast media for MRI, was used. In performing the gamma camera examination using contrast media and $^{99m}Tc$, it is considered significant to check the changes in the uptake counts to improve various diagnosis values.

• The korean journal of orthodontics
• /
• v.35 no.5 s.112
• /
• pp.398-407
• /
• 2005

The present study was conducted to examine the morphometrics and function of the disk on both sides among patients with facial asymmetry (FA) and to elucidate plausible correlations between internal derangement (ID) and FA. The sample was composed of 10 males and 27 females with FA. The disk status of all subjects was evaluated by bilateral high resolution magnetic resonance scans in the sagittal (closed and open) and coronal (closed) planes. Five types of disk displacement were identified accordingly. The disk function was diagnosed as normal disk function, disk displacement with reduction, and disk displacement without reduction. The disk shape on sagittal MRI in closed position was classified as bi-concave, biplanar, funnel/hemiconvex, and deformed. The disk position, translation and rotation were also measured. The difference between the shifted side and non-shifted side was analyzed by statistical analysis. Approximately $70\%$ of the patients in the present study showed unilateral or bilateral ID. It was found that anterior disk displacements (ADD), especially rotational ADD, occurred more frequently in the shifted side, while normal disk position was observed mainly in the non-shifted side (p<0.01). The disk of the shifted side showed significantly deformed configuration and inferior-anterior disk position. However, the disk of the non-deviated side showed hyper-mobility during jaw opening movement. These results demonstrate that in FA patients, the disks status of the shifted side is different from that of the non-shifted side, a phenomenon that could be correlated to facial asymmetry.

• Journal of the Korean Society of Radiology
• /
• v.12 no.2
• /
• pp.193-199
• /
• 2018

In this research, 15 patients were diagnosed with 1.5T and 3.0T MRI instruments (Philips, Medical System, Achieva) to minize Ferromagnetic artifact and find the optimized Tesla. Based on the theory that the 3.0T, when compared to 1.5T, show relatively high signal-to-ratio(SNR), Scan time can be shortened or adjust the image resolution. However, when using the 3.0T MRI instruments, various artifact due to the magnetic field difference can degrade the diagnostic information. For the analysis condition, area of interest is set at the background of the T1, T2 sagittal image followed by evaluation of L3, L4, L5 SNR, length of 3 parts with Ferromagnetic artifact, and Histogram. The validity evaluation was performed by using the independent t test. As a result, for the SNR evaluation, mere difference in value was observed for L3 between 1.5T and 3.0T, while big differences were observed for both L4, and L5(p<0.05). Shorter length was observed for the 1.5T when observing 3 parts with Ferromagnetic artifact, thus we can conclude that 3.0T can provide more information on about peripheral tissue diagnostic information(p<0.05). Finally, 1.5T showed higher counts values for the Histogram evaluation(p<0.05). As a result, when we have compared the 1.5T and 3.0T with SNR, length of Ferromagnetic artifact, Histogram, we believe that using a Low Tesla for Spine MRI test can achieve the optimal image information for patients with disk operation like PLIF, etc. in the past.

• Korean Journal of Radiology
• /
• v.23 no.3
• /
• pp.333-342
• /
• 2022

Objective: Intracranial atherosclerotic stroke occurs through various mechanisms, mainly by artery-to-artery embolism (AA) or branch occlusive disease (BOD). This study evaluated the spatial relationship between middle cerebral artery (MCA) plaques and perforating arteries among different MCA territory infarction types using vessel wall magnetic resonance imaging (VW-MRI). Materials and Methods: We retrospectively enrolled patients with acute MCA infarction who underwent VW-MRI. Thirty-four patients were divided into three groups according to infarction pattern: 1) BOD, 2) both BOD and AA (BOD-AA), and 3) AA. To determine the factors related to BOD, the BOD and BOD-AA groups were combined into one group (with striatocapsular infarction [BOD+]) and compared with the AA group. To determine the factors related to AA, the BOD-AA and AA groups were combined into another group (with cortical infarction [AA+]) and compared with the BOD group. Plaque morphology and the spatial relationship between the perforating artery orifice and plaque were evaluated both quantitatively and qualitatively. Results: The plaque margin in the BOD+ group was closer to the perforating artery orifice than that in the AA group (p = 0.011), with less enhancing plaque (p = 0.030). In the BOD group, plaques were mainly located on the dorsal (41.2%) and superior (41.2%) sides where the perforating arteries mainly arose. No patient in the AA group had overlapping plaques with perforating arteries at the cross-section where the perforator arose. Perforating arteries associated with culprit plaques were most frequently located in the middle two-thirds of the M1 segment (41.4%). The AA+ group had more stenosis (%) than the BOD group (39.73 ± 24.52 vs. 14.42 ± 20.96; p = 0.003). Conclusion: The spatial relationship between the perforating artery orifice and plaque varied among different types of MCA territory infarctions. In patients with BOD, the plaque margin was closer and blocked the perforating artery orifice, and stenosis degree and enhancement were less than those in patients with AA.

• Korean Journal of Radiology
• /
• v.22 no.9
• /
• pp.1451-1461
• /
• 2021

Objective: Adequate methods of combining T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) to assess complete response (CR) to chemoradiotherapy (CRT) for rectal cancer are obscure. We aimed to determine an algorithm for combining T2WI and DWI to optimally suggest CR on MRI using visual assessment. Materials and Methods: We included 376 patients (male:female, 256:120; mean age ± standard deviation, 59.7 ± 11.1 years) who had undergone long-course CRT for rectal cancer and both pre- and post-CRT high-resolution rectal MRI during 2017-2018. Two experienced radiologists independently evaluated whether a tumor signal was absent, representing CR, on both post-CRT T2WI and DWI, and whether the pre-treatment DWI showed homogeneous hyperintensity throughout the lesion. Algorithms for combining T2WI and DWI were as follows: 'AND,' if both showed CR; 'OR,' if any one showed CR; and 'conditional OR,' if T2WI showed CR or DWI showed CR after the pre-treatment DWI showed homogeneous hyperintensity. Their efficacies for diagnosing pathologic CR (pCR) were determined in comparison with T2WI alone. Results: Sixty-nine patients (18.4%) had pCR. AND had a lower sensitivity without statistical significance (vs. 62.3% [43/69]; 59.4% [41/69], p = 0.500) and a significantly higher specificity (vs. 87.0% [267/307]; 90.2% [277/307], p = 0.002) than those of T2WI. Both OR and conditional OR combinations resulted in a large increase in sensitivity (vs. 62.3% [43/69]; 81.2% [56/69], p < 0.001; and 73.9% [51/69], p = 0.008, respectively) and a large decrease in specificity (vs. 87.0% [267/307]; 57.0% [175/307], p < 0.001; and 69.1% [212/307], p < 0.001, respectively) as compared with T2WI, ultimately creating additional false interpretations of CR more frequently than additional identification of patients with pCR. Conclusion: AND combination of T2WI and DWI is an appropriate strategy for suggesting CR using visual assessment of MRI after CRT for rectal cancer.

• Proceedings of the KSMRM Conference
• /
• 2001.11a
• /
• pp.111-111
• /
• 2001

목적： To evaluate the feasibility of the event-related functional MR study using power grip studying the hand motor system 대상 및 방법： Event-related functional MRI was performed on a 1.5T MR unit in seven norm volunteers (man=7, right-handedness=2, left-handedness=5, mean age： 25 years). A single-shot GRE-EPI sequence (TR/TE/flip angle： 1000ms/40ms/90, FOV = 240 mm matrix= 64$\times$64, slice thickness/gap = 5mm/0mm, 7 true axial slices) was used for functiona MR images. A flow-sensitive conventional gradient echo sequence (TR/TE/flip angl 50ms/4ms/60) was used for high-resolution anatomical images. To minimize the gross hea motion, neck-holders (MJ-200, USA) were used. A series of MR images were obtained in axial planes covering motor areas. To exclude motion-corrupted images, all MR images wer surveyed in a movie procedure and evaluated using the estimation of center of mass of ima signal intensities. Power grip task consisted of the powerful grip of all right fingers and hand movement ta used very fast right finger tapping at a speed of 3 per 1 second. All tasks were visual-guid by LCD projector (SHARP, Japan). Two tasks consisted of 134 phases including 7 activatio and 8 rest periods. Active stimulations were performed during 2 seconds and rest period were 15 seconds and total scan time per one task was 2 min 14 sec. Statistical maps we obtained using cross-correlation method. Reference vector was time-shifted by 4 seconds an Gaussian convolution with a FWHM of 4 seconds was applied to it. The threshold in p val for the activation sites was set to be 0.001. All mapping procedures were peformed usin homemade program an IDL (Research Systems Inc., USA) platform. We evaluated the activation patterns of the motor system of power grip compared to hand movement in t event-related functional MRI.

• Investigative Magnetic Resonance Imaging
• /
• v.19 no.3
• /
• pp.168-177
• /
• 2015

Purpose: Brain surface intensity model (BSIM)-based cortical thickness analysis does not require complicated 3D segmentation of brain gray/white matters. Instead, this technique uses the local intensity profile to compute cortical thickness. The aim of the present study was to evaluate intra-rater and inter-rater reliability of BSIM-based cortical thickness analysis using images from elderly participants. Materials and Methods: Fifteen healthy elderly participants (ages, 55-84 years) were included in this study. High-resolution 3D T1-spoiled gradient recalled-echo (SPGR) images were obtained using 3T MRI. BSIM-based processing steps included an inhomogeneity correction, intensity normalization, skull stripping, atlas registration, extraction of intensity profiles, and calculation of cortical thickness. Processing steps were automatic, with the exception of semiautomatic skull stripping. Individual cortical thicknesses were compared to a database indicating mean cortical thickness of healthy adults, in order to produce Z-score thinning maps. Intra-class correlation coefficients (ICCs) were calculated in order to evaluate inter-rater and intra-rater reliabilities. Results: ICCs for intra-rater reliability were excellent, ranging from 0.751-0.940 in brain regions except the right occipital, left anterior cingulate, and left and right cerebellum (ICCs = 0.65-0.741). Although ICCs for inter-rater reliability were fair to excellent in most regions, poor inter-rater correlations were observed for the cingulate and occipital regions. Processing time, including manual skull stripping, was $17.07{\pm}3.43min$. Z-score maps for all participants indicated that cortical thicknesses were not significantly different from those in the comparison databases of healthy adults. Conclusion: BSIM-based cortical thickness measurements provide acceptable intra-rater and inter-rater reliability. We therefore suggest BSIM-based cortical thickness analysis as an adjunct clinical tool to detect cortical atrophy.

• Investigative Magnetic Resonance Imaging
• /
• v.14 no.2
• /
• pp.134-138
• /
• 2010

Parosteal lipoma is a rare benign tumor containing mature adipose tissue having an intimate relationship to the periosteum. Characteristically, this tumor presents as a lipomatous mass adjacent to bone, eliciting variable reactive changes in the underlying cortex. We report a case of parosteal lipoma of the foot. The MR findings consisted of juxtacortical lipomatous mass abutting to bony protuberance, with internal fibrous striations, and osseous reaction in the adjacent bone. By the aid of multiplanar imaging capability, high spatial and contrast resolution of MRI, characteristic features of parosteal lipoma can lead to diagnosis on imaging.