• Journal of Korean Neurosurgical Society
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• v.41 no.1
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• pp.39-42
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• 2007

Primary intracranial melanoma is uncommon. These tumors most commonly occur at the temporal lobe, cerebellum and cerebellopontine angle. We report a case of intracranial malignant melanoma of the occipital lobe in a 60-year-old man who presented with headache and visual disturbance. The mass showed hyperintensity on T1-weighted images and hypointensity on T2-weighted magnetic resonance images. He underwent gross total removal of tumor and received radiotherapy. Follow-up imaging studios showed neither recurrence nor any signs of residual disease for 4 months.

• Proceedings of the KSMRM Conference
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• 1996.10a
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• pp.67-67
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• 1996

• Journal of Korean Neurosurgical Society
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• v.49 no.1
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• pp.26-30
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• 2011

Objective: The primary objective of this study was to perform a retrospective evaluation of the radiological and pathological features influencing the formation of peritumoral brain edema (PTBE) in meningiomas. Methods: The magnetic resonance imaging (MRI) and pathology data for 86 patients with meningiomas, who underwent surgery at our institution between September 2003 and March 2009, were examined. We evaluated predictive factors related to peritumoral edema including gender, tumor volume, shape of tumor margin, presence of arachnoid plane, the signal intensity (SI) of the tumor in T2-weighted image (T2WI), the WHO histological classification (GI, GII/GIII) and the Ki-67 antigen labeling index (LI). The edema-tumor volume ratio was calculated as the edema index (EI) and was used to evaluate peritumoral edema. Results: Gender (p=0.809) and pathological finding (p=0.084) were not statistically significantly associated with peritumoral edema by univariate analysis. Tumor volume was not correlated with the volume of peritumoral edema. By univariate analysis, three radiological features, and one pathological finding, were associated with PTBE of statistical significance: shape of tumor margin (p=0.001), presence of arachnoid plane (p=0.001), high SI of tumor in T2WI (p=0.001), and Ki-67 antigen LI (p=0.049). These results suggest that irregular tumor margins, hyperintensity in T2WI, absence of arachnoid plane on the MRI, and high Ki-67 LI can be important predictive factors that influence the formation of peritumoral edema in meningiomas. By multivariate analysis, only SI of the tumor in T2WI was statistically significantly associated with peritumoral edema. Conclusion: Results of this study indicate that irregular tumor margin, hyperintensity in T2WI, absence of arachnoid plane on the MRI, and high Ki-67 LI may be important predictive factors influencing the formation of peritumoral edema in meningiomas.

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

• Journal of Veterinary Clinics
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• v.33 no.1
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• pp.10-15
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• 2016

The purpose of this study was to establish reproducible ischemic infarction model using allogenic blood clot in beagle dogs and identify induced ischemic lesion after middle cerebral artery occlusion using magnetic resonance imaging (MRI) and histopathologic findings. Twenty eight male beagle dogs with no evidence of neurologic disease were experimented. Allogenic embolus was made using a healthy beagle dog. After internal carotid artery (ICA) was exposure, 16G catheter was introduced through the ICA. The dog was administered 0.3 ml blood clot for 15 seconds followed by 3 ml of saline for 15 seconds. MRI scans were performed with 1.5T to evaluate ischemic lesion at 7 days after middle cerebral artery occlusion procedure. Evaluation parameters of MRI include location, distribution, infarction type, margin, shape, mass effect and intensity of T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), fluid attenuated inversion recovery (FLAIR) sequence, diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC). On MRI, all dogs (28/28) showed focal or multifocal lesion including telencephalon and thalamus lesions, especially caudate nucleus (24/28). These lesions had well-defined margin from adjacent brain parenchyma, none or mild mass effect and various shape. Most of dogs appeared hyperintensity on T1WI, T2WI, FLAIR, and DWI/ADC, corresponding to chronic infarction. These lesions were histopathologically confirmed atrophic changes and unstained lesion. In conclusion, MRI is the useful method to provide information about ischemic infarction in dogs and the best reproducible ischemic infarction model was developed by using allogenic blood clot.

• Journal of the Korean Society of Radiology
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• v.85 no.3
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• pp.607-617
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• 2024

Purpose Recent studies have demonstrated the usefulness of diffusion-weighted MR neurography (DW MRN) for assessing nerve roots. This study aimed to evaluate the utility of DW MRN with a unidirectional motion-probing gradient (MPG) for the lumbar nerve roots at 1.5T MR. Materials and Methods Sixty-four lumbar spine MRI scans with DW MRN using anteroposterior unidirectional MPG were retrospectively analyzed. Any changes in the 512 lumbar spinal nerve roots from L3 to S1 were evaluated using T2-weighted imaging (T2WI), contrast-enhanced T1-weighted imaging (CE T1WI), and DW MRN, with agreement and correlation analysis. Results T2WI revealed compression of 78 nerve roots, and CE T1WI revealed 52 instances of nerve root enhancement. Sixty-seven nerve roots showed swelling and hyperintensity on DW MRN. A total of 42 nerve roots showed changes in the CE T1WI and DW MRN sequences. Moderate to substantial agreement and moderate positive correlation were observed between DW MRN and CE T1WI, as well as DW MRN and T2WI (κ = 0.59-0.65, ρ = 0.600-0.653). Conclusion DW MRN with unidirectional anteroposterior MPG can help evaluate neuritisrelated changes in spinal nerve roots and could serve as a sequence capable of complementing or substituting gadolinium CE imaging.

• Progress in Medical Physics
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• v.5 no.1
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• pp.3-12
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• 1994

Purporse : It is known that detection of calcification by MRI is difficulty in intracranial calcified lesions, but author tried to evaluate the signal intensity image of calcification by MR with experimental model. Subjects & Methods : Author analyzed and compared with values of calcium carbonate and hydroxyapatite phantoms by each concentration (10, 20, 30, 40, 50%) and size(1-10mm), measured ROI attenuating from CT and MRI(TlWI & T2WI). Results : The high concentration of calcium carbonate is, the lower the signal intensity of calcium carbonate phantom is both T1 & T2WI. For concentration of Hydroxyapatite of up to 30% by weight the signal intensity on standard T1 weighted images increased but subsequently decreased. Hyperintensity does not preclude calcification as a cause of the signal alteration-an observation that all radiologists interpreting MR images need to be aware of. Conclusion: The signal intensity of intracranial calcification is various on MR imaging in concerning with components, concentration, & size of calcification, and especially high signal intensity of intracranial calcification noted differencial diagnosis.

• Korean Journal of Radiology
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• v.1 no.3
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• pp.165-168
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• 2000

We present two cases of solitary necrotic nodules of the liver which on radiologic images mimicked hepatic metastasis. Solitary necrotic nodule of the liver is a rare but benign entity which histopathologically consists of an outer fibrotic capsule with inflammatory cells and a central core of amorphous necrotic material. The lesion was seen on contrast-enhanced CT as an ovoid-shaped hypoattenuating nodule; on CT during hepatic arteriography as enhancing nodule; on intraoperative US as a target-appearing hypoechoic nodule; on T2WI as a hyperintensity nodule, and on dynamic MR as a subtle peripheral enhancing nodule. Although the radiologic features are not specific, solitary necrotic nodule of the liver should be included in the differential diagnosis of hepatic metastasis.

• Journal of Veterinary Clinics
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• v.27 no.5
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• pp.546-552
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• 2010

Previous studies could not offer available guideline to decide size of balloon and grade of injury before induction of spinal cord injury (SCI) because grade of SCI was assessed after inserting a catheter and each experimental animal were different in body size and weight as well as in species. This study was performed to provide guideline for standardized SCI model. Eight healthy adult beagle dogs that had 8 mm of spinal canal height were assigned to four groups according to the diameter of balloon and compression time: 4 mm/3hrs, 4 mm/6hrs, 4 mm/12hrs and 6 mm/3hrs group. Radiography was performed to standardize between experimental animal and balloon before selecting balloon diameter to induce SCI. Behaviors outcomes, somatosensory evoked potentials (SEPs), magnetic resonance imaging (MRI) and histopathological examination were evaluated. Behaviors outcomes and SEPs were not available to assess grade of SCI and those only indicate SCI. The damaged area was revealed clear hyperintensity on STIR image and T2WI after induction of SCI. The hyperintense area on MRI was cranially and caudally expanded with increasing of the diameter of balloon or the compression time. Well corresponded to expanding of hyperintense area on MRI, the damaged region and the numbers of caspase-3 and PARP immunoreactive cells were increased on histopathological findings. Therefore, these results will be considered fundamental data to induce standardized SCI model in experimental animal that has various weight and size.