• Korean Journal of Radiology
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• v.23 no.2
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• pp.246-255
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• 2022

Objective: To determine the usefulness of Silent MR angiography (MRA) for evaluating intracranial aneurysms treated with stent-assisted coil embolization. Materials and Methods: Ninety-nine patients (101 aneurysms) treated with stent-assisted coil embolization (Neuroform atlas, 71 cases; Enterprise, 17; LVIS Jr, 9; and Solitaire AB, 4 cases) underwent time-of-flight (TOF) MRA and Silent MRA in the same session using a 3T MRI system within 24 hours of embolization. Two radiologists independently interpreted both MRA images retrospectively and rated the image quality using a 5-point Likert scale. The image quality and diagnostic accuracy of the two modalities in the detection of aneurysm occlusion were further compared based on the stent design and the site of aneurysm. Results: The average image quality scores of the Silent MRA and TOF MRA were 4.38 ± 0.83 and 2.78 ± 1.04, respectively (p < 0.001), with an almost perfect interobserver agreement. Silent MRA had a significantly higher image quality score than TOF MRA at the distal internal carotid artery (n = 57, 4.25 ± 0.91 vs. 3.05 ± 1.16, p < 0.001), middle cerebral artery (n = 21, 4.57 ± 0.75 vs. 2.19 ± 0.68, p < 0.001), anterior cerebral artery (n = 13, 4.54 ± 0.66 vs. 2.46 ± 0.66, p < 0.001), and posterior circulation artery (n = 10, 4.50 ± 0.71 vs. 2.90 ± 0.74, p = 0.013). Silent MRA had superior image quality score to TOF MRA in the stented arteries when using Neuroform atlas (4.66 ± 0.53 vs. 3.21 ± 0.84, p < 0.001), Enterprise (3.29 ± 1.59 vs. 1.59 ± 0.51, p = 0.003), LVIS Jr (4.33 ± 1.89 vs. 1.89 ± 0.78, p = 0.033), and Solitaire AB stents (4.00 ± 2.25 vs. 2.25 ± 0.96, p = 0.356). The interpretation of the status of aneurysm occlusion exhibited significantly higher sensitivity with Silent MRA than with TOF MRA when using the Neuroform Atlas stent (96.4% vs. 14.3%, respectively, p < 0.001) and LVIS Jr stent (100% vs. 20%, respectively, p = 0.046). Conclusion: Silent MRA can be useful to evaluate aneurysms treated with stent-assisted coil embolization, regardless of the aneurysm location and type of stent used.

• Journal of the Korean Society of Radiology
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• v.84 no.4
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• pp.970-976
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• 2023

This study reports on diffuse leptomeningeal glioneuronal tumor (DL-GNT) in a 29- year-old male. DL-GNT is a rare central nervous system (CNS) tumor mostly seen in children and only few cases have been reported in adult patients. Our patient presented with a chronic headache that lasted for five months. MR imaging showed mild hydrocephalus, multiple rim-enhancing nodular lesions in the suprasellar cistern, diffuse leptomeningeal enhancement in the lumbosacral area, and multiple small non-enhancing cyst-appearing lesions not suppressed on fluid attenuated inversion recovery (FLAIR) images in the bilateral basal ganglia, thalami, and cerebral hemispheres. Under the impression of germ cell tumor with leptomeningeal seeding, the patient underwent trans-sphenoidal tumor removal. DL-GNT was pathologically confirmed and FGFR1 mutation was detected through a next-generation sequencing test. In conclusion, a combination of leptomeningeal enhancement and multiple parenchymal non-enhancing cyst-appearing lesions not suppressed on FLAIR images may be helpful for differential diagnosis despite overlapping imaging features with many other CNS diseases that have leptomeningeal enhancement.

• Journal of the Korean Society of Radiology
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• v.85 no.1
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• pp.184-196
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• 2024

Purpose We investigated potentially promising imaging findings and their combinations in the evaluation of cognitive decline. Materials and Methods This retrospective study included 138 patients with subjective cognitive impairments, who underwent brain MRI. We classified the same group of patients into Alzheimer's disease (AD) and non-AD groups, based on the neuropsychiatric evaluation. We analyzed imaging findings, including white matter hyperintensity (WMH) and cerebral microbleeds (CMBs), using the Kruskal-Wallis test for group comparison, and receiver operating characteristic (ROC) curve analysis for assessing the diagnostic performance of imaging findings. Results CMBs in the lobar or deep locations demonstrated higher prevalence in the patients with AD compared to those in the non-AD group. The presence of lobar CMBs combined with periventricular WMH (area under the ROC curve [AUC] = 0.702 [95% confidence interval: 0.599-0.806], p < 0.001) showed the highest performance in differentiation of AD from non-AD group. Conclusion Combinations of imaging findings can serve as useful additive diagnostic tools in the assessment of cognitive decline.

• Journal of the Korean Society of Radiology
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• v.84 no.1
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• pp.150-169
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• 2023

Multiple myeloma (MM) is a malignant hematologic disease caused by the proliferation of clonal plasma cells in the bone marrow, and its incidence is increasing in Korea. With the development of treatments for MM, the need for early diagnosis and treatment has emerged. In recent years, the International Myeloma Working Group (IMWG) has been constantly revising the laboratory and radiological diagnostic criteria for MM. In addition, as whole-body MRI (WBMR) has been increasing used in the diagnosis and treatment response evaluation of patients with MM, the Myeloma Response Assessment and Diagnosis System (MY-RADS) was created to standardize WBMR image acquisition techniques, image interpretation, and response evaluation methods. Radiologists need to have a detailed knowledge of the features of MM for accurate diagnosis. Thus, in this review article, we describe the imaging method for MM according to the latest IMWG guidelines as well as the image acquisition and response evaluation technique for WBMR according to MY-RADS.

• Journal of the Korean Society of Radiology
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• v.84 no.3
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• pp.736-744
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• 2023

Adult-onset Alexander Disease (AOAD) is a rare genetically determined leukoencephalopathy that presents with ataxia, spastic paraparesis, or brain stem signs including speech abnormalities, swallowing difficulties, and frequent vomiting. The diagnosis of AOAD is frequently proposed based on the findings on MRI. We demonstrate two cases (37-year-old female and 61-year-old female) with characteristic imaging findings and changes in follow-up MRI in patients with AOAD, which were confirmed via glial fibrillary acidic protein (GFAP) mutation analysis. On MRI, the typical tadpole-like brainstem atrophy and periventricular white matter abnormalities were noted. The presumptive diagnoses were made based on the typical MRI appearances and, subsequently, confirmed via GFAP mutation analysis. Follow-up MRI demonstrated the progression of atrophy in the medulla and upper cervical spinal cord. Our report could help raise awareness of characteristic MRI findings of AOAD, thus helping clinicians use GFAP analysis for AOAD diagnosis confirmation.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.683-690
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• 2009

The purpose of this study is to evaluate the usefulness of high-b-values diffusion weighted magnetic resonance imaging for the preoperative detection of focal rectum cancers. 60patients with diffusion weighted imaging were evaluated for the presence of rectal cancers. Forty were male and twenty were female, and their ages ranged from 38 to 71 (mean, 56) years. Used equipment was 1.5Tesla MRI((GE, General Electric Medical System, Excite HD). Examination protocols were used the fast spin echo T2, T1 weighted imaging. All examination protocols were performed by the same location with diffusion weighted imaging for accuracy detection. The b-values used in DWI were 250, 500, 750, 1000. 1500, 2000$(s/mm^2)$. The rectum, bladder to tumor contrast-to-noise ratio (CNR) of MR images were quantitativlely analyzed using GE software Functool tool, four experienced radiologists and three radiotechnologists qualitatively evaluated image quality in terms of image artifacts, lesion conspicuity and rectal wall. These data were analysed by using ANOVA and Freedman test with each b-value(p<0.05). Contrast to noise ratio of rectum, bladder and tumor in b-value 1000 were 27.21, 24.44, respectively(p<0.05) and aADC value was $0.73\times10^{-3}$. As a qualitative analysis, the conspicuity and discrimination from the rectal wall of lesions were high results as $4.0\pm0.14$, $4.4\pm0.16$ on b-value 1000(p<0.05), image artifacts were high results as $4.8\pm0.25$ on b-value 2000(p<0.05). In conclusion, DWI was provided useful information with depicting the pre-operative detection of rectal cancers, High-b-value 1000 image was the most excellent DWI value.

• Journal of the Korean Arthroscopy Society
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• v.6 no.2
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• pp.109-114
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• 2002

Propose : The purpose of this retrospective study was to test the posterior cruciate ligament (PCL index) for diagnosis of a tear of the anterior cruciate ligament (ACL) by means of MR imaging. Materials and Methods : From Mar. 1997 to Feb. 2001, concomitant magnetic resonance imaging (MRI) and knee joint arthroscopy were performed in 56 patients of either pain or instability of the knee. The shortest distance between the femoral and tibial attachment of PCL (X) and the distance from that line to the tip of the arc marked by the PCL (Y) on the sagittal plane images were measured. The quotient of these two parameters (Y/X) defined the PCL index. Results : Using MRI diagnosis, there were 35 patients diagnosed with ACL rupture and 21 patients were ruled out of ACL injury. Using arthroscopy, 32 of the 35 patients diagnosed by MRI showed ACL rupture, and 20 of the 21 patients were ruled out of ACL injury. The mean PCL index was 0.40 in the 33 patients diagnosed with ACL rupture through arthroscopy. The mean PCL index was 0.23 in 23 patients with an uninjured ACL through arthroscopy. In 33 patients with ruptured ACL, this value exceeds 0.31. The index value was 0.31 in 3 patients with uninjured ACL. The value of the index was not above 0.31 with an uninjured ACL. PCL index on MRI had a sensitivity of $91\%$ and a specificity of $94\%$ for determining the status of the anterior cruciate ligament. Conclusion : Injury to the ACL changes the PCL index markedly. In diagnostically unreliable MR images, amelioration of the PCL index could help in the diagnosis of ACL injury.

• Journal of the Korean Magnetics Society
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• v.26 no.6
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• pp.219-225
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• 2016

In this study, for assessment of degenerative knee joint cartilage disease we acquired images by fat suppressed 3D spoiled gradient recalled (SPGR) and fat suppressed 3D $T2^*$ weighted imaging techniques. To do a quantitative evaluation, the knee joint cartilage was divided into medial femoral cartilage (MFC), medial tibial cartilage (MTC), lateral femoral cartilage (LFC), lateral femoral cartilage (LFC) and patella cartilage (Pat) to measure their respective signal intensity values, signal-to-noise ratio, and contrast-to-noise ratio. As for the measured values, statistical significance between two techniques was verified by using Mann-Whitney U-Test. To do a qualitative evaluation, two radiologists have examined images by techniques after which image artifact, cartilage surface, tissue contrast, and depiction of lesion distinguishing were evaluated based on 4-point scaling (1: bad, 2: appropriate, 3: good, 4: excellent), and based on the result, statistical significance was verified by using Kappa-value Test. 3.0T MR system and HD T/R 8ch knee array coil were used to acquire images. As a result of a quantitative analysis, based on SNR values measured by using two imaging techniques, MFC, LFC, LTC, and Pat showed statistical significance (p < 0.05), but MTC did not (p > 0.05). As a result of verifying statistical significance for measured CNR value, MFC, LFC, and Pat showed statistical significance (p < 0.05), while MTC and LTC did not show statistical significance (p > 0.05). As a result of a qualitative analysis, by comparing mean values for evaluated image items, 3D $T2^*$ weighted Image has indicated a slightly higher value. As for conformance verification between the two observers by using Kappa-value test, all evaluated items have indicated statistically significant results (p < 0.05). 3D $T2^*$ weighted technique holds a clinical value equal to or superior to 3D SPGR technique with respect to evaluating images, such as distinguishing knee joint cartilages, comparing nearby tissues contrast, and distinguishing lesions.

• Progress in Medical Physics
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• v.14 no.2
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• pp.124-130
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• 2003

Currently, as a consequence of PACS (Picture Archiving Communication System) implementation many hospitals are replacing conventional film-type interpretations of diagnostic medical images with new digital-format interpretations that can also be saved, and retrieve However, the big limitation in PACS is considered to be the lack of mobility. The purpose of this study is to determine the optimal communication packet size. This was done by considering the terms occurred in the wireless communication. After encoding medical image using JPGE2000 image compression method, This method embodied auto-error correction technique preventing the loss of packets occurred during wireless communication. A PC class server, with capabilities to load, collect data, save images, and connect with other network, was installed. Image data were compressed using JPEG2000 algorithm which supports the capability of high energy density and compression ratio, to communicate through a wireless network. Image data were also transmitted in block units coeded by JPEG2000 to prevent the loss of the packets in a wireless network. When JPGE2000 image data were decoded in a PUA (Personal Digital Assistant), it was instantaneous for a MR (Magnetic Resonance) head image of 256${\times}$256 pixels, while it took approximately 5 seconds to decode a CR (Computed Radiography) chest image of 800${\times}$790 pixels. In the transmission of the image data using a CDMA 1X module (Code-Division Multiple Access 1st Generation), 256 byte/sec was considered a stable transmission rate, but packets were lost in the intervals at the transmission rate of 1Kbyte/sec. However, even with a transmission rate above 1 Kbyte/sec, packets were not lost in wireless LAN. Current PACS are not compatible with wireless networks. because it does not have an interface between wired and wireless. Thus, the mobile JPEG2000 image viewing system was developed in order to complement mobility-a limitation in PACS. Moreover, the weak-connections of the wireless network was enhanced by re-transmitting image data within a limitations The results of this study are expected to play an interface role between the current wired-networks PACS and the mobile devices.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.178-186
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• 2009

The quality control is needed to ensure the accuracy of medical information and achieved by evaluating the performance of and maintaining the system and practicing various measurements and evaluations. The Korean Institute for Accreditation of Medical Image, therefore, have held educational program for quality control of special medical equipments. The major of programs participants, however, are radiology specialists with only small number of radiological technologists from some hospitals, furthermore, the follow-up education and the share of information between participants and non-participants are insufficient in general, thus, the knowledge level of radiological technologists, regardless of their participation, is relatively low. This study carried out the questionnaire research for the 500 radiological technologists registered in Korean Society of MRI Technology, on the basis of 2008, and performed analysis for five months from May to Oct., 2008. The questionnaires were delivered by post to each radiological technologists and the response rate was 36%(n=180). The results of this revealed that the 86.7% of respondents felt the necessity of inspection on quality management, while only the 27.8% completed the educational program for manager of special medical equipment. and only the half(53.9%) had the knowledge about inspection on quality management. The completion of educational program had no correlations with sex, age, size of occupying hospital, the number of radiological technologists in occupying site and MRI laboratory, career year of general radiologist and in MRI laboratory, and the presence of biomedical engineering department in occupying hospital. The 78.0% of participants at the educational program for quality management held by the Korean Institute for Accreditation of Medical Image had the knowledge about inspection on quality management(p<.05) whereas the 43.9% of the hospitals held such program and the 54.4% of radiological technologists from those hospitals had related knowledge, which indicated that such programs held by hospitals had not effects on the knowledge level of radiological technologists. This indicates also that the contents, methods, and other conditional factors of educational programs are important for the outcome of them.