• Investigative Magnetic Resonance Imaging
• /
• v.5 no.2
• /
• pp.116-122
• /
• 2001

Purpose : To find sensitivity of MRI imaging methods to slow flow phantom study was performed with conventional Spin-Echo, gradient echo based Phase Contrast, fast GRASS, and heavily T2-weighted Fast Spin Echo pulse sequences. Materials and Methods : A siphon driven flow phantom was constructed with a ventriculo-peritoneal shunt catheter and a GE phantom to achieve continuous variable flow. Four different pulse sequences including Spin-Echo, Phase Contrast, GRASS and Heavily T2-weighted Fast Spin Echo were evaluated to depict slow flow in the range from 0.08 ml/min to 1.7 ml/min and to compare signal intensities between static fluid and flowing fluid. Results : In the slow flow above 0.17 ml/min conventional Spin-Echo showed superior apparent contrast between static and flowing fluid while GRASS was more sensitive to the very slow flow below 0.17 ml/mim. It was not accurate to calculate flow and velocity below 0.1 ml/min with a modified PC imaging. Conclusion : Four different MR pulse sequences demonstrated different sensitivity to the range of slow flow from 0.08 ml/min to 1.7 ml/min. This finding may be clinically useful to measure CSF shunt flow or detecting CSF collection and thrombosis.

• Investigative Magnetic Resonance Imaging
• /
• v.4 no.1
• /
• pp.34-41
• /
• 2000

Purpose: To evaluate the clinical usefulness of diffusion weighted MR imaging(DWI) in the differential diagnosis of brain tumors. Materials and methods: DWI and conventional MR images of nineteen patients with brain tumors(10 metastatic tumors, 4 high grade gliomas, 4 low grade astrocytomas, one oligodendroglioma)were obtained on 1.5T unit. DWI was obtained using single shot spin echo planar imaging with b-value near 1000. We analyzed the signal intensities of lesions including solid portion, necrotic or cystic portion and peritumoral edema of brain tumors (classified five grades comparison with the signal intensities of brain parenchyma and CSF)and calculate the SIR(signal intensity ratio)of lesions to the contralateral normal brain parenchyma. We analyzed statistically the signal intensities and SIR of tumors using independence T test. Results: In solid portions of tumors, all the metastatic tumors and high grade gliomas showed high signal intensities, but low grade astrocytomas and oligodendroglioma showed iso or slight high signal intensities to the normal brain parenchyma. The SIR of solid portion has positive correlation with malignant pot ential(metastatic tumors 1.52, high grade gliomas 1.38, low grade astrocytomas 1.16, oligodendroglioma 1.31)(p < 0.05). In peritumoral edema where seen in 14 tumors, seven of 10 metastatic tumors and two of 4 high grade gliomas showed iso signal intensities, whereas edemas in other 5 brain tumors showed hyperintense to the normal brain parenchyma. The SIRs of peritumoral edemas in metastatic tumors (1.14) was lower than high grade gliomas(1.31),but statistically insignificant. The SIR of cystic or necrotic portion of brain tumors was 0.63. In non enhancing solid portions, three of six cases showed hyperintense to the adjacent peritumoral edema. Conclusion: On DWI, the signal intensities of solid portion has positive correlation with malignant potential, and perilesional edema of brain tumors appear various signal intensities owing to "T2 shine through effect" and the extensiveness of vasogenic edema. Another merit using DWI on the evaluation of brain tumors is to improved better delineation of tumor margins from the adjacent edemas, especially at the non enhancing solid portion of the tumors.

• The Korean Journal of Nuclear Medicine
• /
• v.37 no.4
• /
• pp.229-234
• /
• 2003

Purpose: Since the prognosis of measles encephalitis is poor, early diagnosis and proper management are very important to improve clinical outcomes. We compared Tc-99m ECD brain SPECT (SPECT) with MR imaging (MRI) for the detection of acute measles encephalitis. Materials and Methods: Eleven patients(M : F=4 : 7, age range 18 months-14 yrs) with acute measles encephalitis were enrolled in this studies. All of them underwent both MRI and SPECT. The results of SPECT were scored from 0 (normal) to 3 (most severe defect) according to perfusion state. We compared two image modalities for the detection of brain abnormality in acute measles encephalitis. Results: Seven of 11 patients (63.6%) revealed high signal intensity in the white matter on T2WI of MRI, on the other hand all patients (100%) showed hypoperfusion on SPECT. Severe perfusion deficits above score 2 were located with decreasing frequencies in the frontal lobe (81.8%), temporal lobe (72.7%), occipital lobe (27.3%), basal ganglia (27.3%), and parietal lobe (9.1%). Conclusion: We conclude that SPECT is more useful than MRI for the detection of brain involvement in patients with acute measles encephalitis.

• Investigative Magnetic Resonance Imaging
• /
• v.5 no.2
• /
• pp.130-137
• /
• 2001

Purpose : Our purpose was to compare maximum relative cerebral blood volume (rCBV) with histologic grade of cerebral gliomas. Materials and methods : First-pass perfusion MR imaging was performed preoperatively in 16 patients with pathologically proven cerebral gliomas (7 glioblastoma, 2 anaplastic astrocytoma, 1 anaplastic oligodendroglioma, 5 low-grade astrocytoma, and 1 low-grade oligodendroglioma). Maximum rCBV was compared with histologic diagnosis and grade of the tumor. Results : Maximum rCBVs of glioblastomas were in the range of 433% to-1330% (average, 790 %), as compared with those of contra-lateral normal white matters. Maximum rCBVs of two non-enhancing anaplastic astrocytomas were 66% and 284%, respectively. Maximum rCBV of one well-enhancing anaplastic oligodendroglioma was 702%. Maximum rCBVs of low-grade astrocytomas were in the range of 80%-369% (average, 202%). Maximum rCBV of one low-grade oligodendroglioma was 1450%, even higher than those of glioblastomas. Conclusion : Maximum rCBV was higher in glioblastoma than in low-grade astrocytoma without overlapping. However, there was no difference of maximum rCBV between non-enhancing anaplastic astrocytoma and low-grade astrocrtoma.

• Journal of The Korean Society of Inherited Metabolic disease
• /
• v.12 no.1
• /
• pp.49-53
• /
• 2012

X-linked adrenoleukodystrophy (ALD) is a rare inherited metabolic disease which results in impaired peroxisomal ${\beta}$-oxidation and the accumulation of very long chain fatty acids (VLCFA) in the adrenal cortex, the myelin of the central nervous system, and the testes. X-linked ALD is caused by mutations in the ABCD1 gene encoding an ATP-binding cassette transporter superfamily located in the peroxisomal membrane. This disease is characterized by a variety of phenotypes. The classic childhood cerebral ALD is a rapidly progressive demyelinating condition affecting the cerebral white matter before the age of 10 years in boys. We report the case of a 8-year-old with childhood cerebral X-linked ALD who developed inattention, hyperactivity, motor incoordination and hemiparesis. We diagnosed ALD with elevated plasma very long chain fatty acid level and diffuse high signal intensity lesions in both parieto-occipital white matter and cerebellar white matter in brain MRI. We identified a novel c.983delT (p.Met329CysfsX7) mutation of the ABCD1 gene. There is no correlation between X-ALD phenotype and mutations in the ABCD1 gene. Further studies for searching additional non-genetic factor which determine the phenotypic variation will be needed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.5
• /
• pp.2133-2141
• /
• 2012

The Purpose of this study was to report magnetic resonance imaging(MRI) changes of six cases of Lumbar herniated disc which was treated with spinal decompression therapy, oriental medical therapy. 'Disc heights' were measured on sagittal view of $T_2$-weighted MRI. Size of the herniated disc was measured by MRI and 'disc herniations index'. The grading system and algorithm for 'disc degeneration' were based on MRI signal intensity, disc structure, distinction between nucleus and anulus, and disc height. Data for disc height, disc herniations index and disc degeneration grade were collected before and after the treatment together with calculation from the MRI. Case studies were showed that decompression therapy for the herniated disc has an positive effect on disc herniations index, disc regeneration, not disc heights. The clinical evidence for the use of decompression in herniated disc remains inconclusive because of limited researches. Further trials, which give attention to these areas, are needed before any firm conclusions may be made.

• Clinical and Experimental Pediatrics
• /
• v.51 no.12
• /
• pp.1342-1345
• /
• 2008

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare white matter disorder, first described in the early 1990s. The brain in patients with MLC appears swollen on MRI, with diffuse white matter abnormalities; in addition, there is an invariable presence of subcortical cysts, primarily in the anterior temporal region sparing the deep white matter, basal ganglia, thalami, and cerebellum. Patients with MLC present with macrocephaly and neurological abnormalities such as motor deterioration, ataxia, spasticity, and cognitive deficits. We report a twenty-month-old boy who presented with seizures and macrocephaly, delay in development, and abnormal brain MRI findings compatible with the diagnosis of MLC. The brain MRI revealed bilateral hypersignal intense subcortical white matter regions in the frontal, temporal, and parietal lobes on T2-weighted images, which were not yet associated with cystic changes. During follow-up, the frequency of seizures decreased after anticonvulsant medication was started, but the head circumference remained above the 97th percentile, and the patient continued to have developmental delay.

• Journal of the Korean Society of Radiology
• /
• v.10 no.4
• /
• pp.279-284
• /
• 2016

Single-shot echo planar imaging(SS-EPI) is well established as high sensitivity for ischemic stroke. However, it is prone to susceptibility artifact in brain stem that diminish the image quality. single-shot turbo spin echo(SS-TSE) is a new DWI technique that can reduce susceptibility artifact. Thus, this research was conducted so as to reduce geometric distortion in brain stem by using single-shot turbo spin echo technique. Thirty patients without brain disease underwent diffusion MR on a 3T scanner with SS-EPI and SS-TSE. Obtained images with both sequences were analyzed for geometric distortion and error percentage as well. Image quality in terms of geometric distortion of SS-TSE were found to be significantly better than those for SS-EPI. And error percentage was considerably reduced for 2.4% of b0 image(from 11.1% to 8.7%), 1.2% of b1000 image(from 11.4% to 10.1%), respectively. In summary, diffusion MR using SS-TSE significantly reduce geometric distortion compared to SS-EPI in brain stem and may provide improved diagnostic performance.

• Investigative Magnetic Resonance Imaging
• /
• v.18 no.3
• /
• pp.225-231
• /
• 2014

Purpose : The biceps femoris tendon (BFT) and lateral collateral ligament (LCL) in the knee were formerly known to form a conjoined tendon at the fibular attachment site. However, the BFT and LCL are attached into the fibular head in various patterns. We classified insertion patterns of the BFT and LCL using MR imaging, and analyzed whether the LCL attaches to the fibular head or not. Materials and Methods: A total of 494 consecutive knee MRIs of 470 patients taken between July 2012 and December 2012 were retrospectively reviewed. There were 224 males and 246 females, and patient age varied from 10 to 88 (mean, 48.6). The exclusion criteria were previous surgery and poor image quality. Using 3T fat-suppressed proton density-weighted axial images, the fibular insertion patterns of the BFT and LCL were classified into following types: type I (the LCL passes between the anterior arm and direct arm of the BFT's long head), type II (the LCL joins with anterior arm of the long head of the BFT), type III (the BFT and LCL join to form a conjoined tendon), type IV (the LCL passes laterally around the anterior margin of the BFT), and type V (the LCL passes posteriorly to the direct arm of the BFT's long head). Results: Among the 494 cases of the knee MRI, there were 433 (87.65%) type I cases, 21 (4.25%) type II cases, 2 (0.4%) type III cases, 16 (3.23%) type IV cases, and 22 (4.45%) type V cases. There were 26 cases (5.26%) in which the LCL and BFT were not attached into the fibular head. Conclusion: The fibular attachment pattern of the BFT and LCL shows diverse types in MR imaging. The LCL does not adhere to the head in some patients.

• Journal of the Korean Society of Radiology
• /
• v.85 no.3
• /
• pp.682-690
• /
• 2024

Acute necrotizing encephalopathy (ANE) is a rare immune-mediated complication of a viral infection commonly involving the bilateral thalamus and has been reported mainly in children. Here, we describe the MRI findings of coronavirus disease 2019 (COVID-19)-associated ANE in two pediatric patients, including a 7-year-old girl with fever and mental change, and a 6-year-old girl with fever and generalized seizures. Brain MRI revealed symmetrical T2 fluid attenuated inversion recovery high-signal intensity lesions in the bilateral thalamus with central hemorrhage. In one patient, the thalamic lesions showed a tri-laminar pattern on the apparent diffusion coefficient map. This report emphasizes the importance of creating awareness regarding these findings in patients with COVID-19, particularly in children with severe neurological symptoms. Furthermore, it provides a literature review of several documented cases of COVID-19 presenting with bilateral thalamic hemorrhagic necrosis, suggesting a diagnosis of ANE.