PURPOSE: To see the stability and error in the diffusion-weighted magnetic resonance (MR) imaging technique in the experimental models and to observe the signal intensities in the early cerebral lesions of the animal models. MATERIALS AND METHODS: Diffusion coefficients of acetone and distilled water were measured by diffusion-weighted MR image and were compared with actual values. Differentiation of diffusion from perfusion were done at the resin flow phantom. The signal intensities caused by early parenchymal changes were measured in normal, hypovolemic, and embolic, and dead animal models by using diffusion-weighted image and compared with pathoIogic finding and vital staining. RESULTS: Diffusion coefficients of acetone and distilled water were 4.48 x 10-3 and 2.72 x 10-3 which were very close to the actual values. Diffusion-weighted MR image obtained at flow phantom was not affected by flow (perfusion) at the 100-400 of b-factor range. Animal study done at that b-factor range revealed a significant signal difference between the left and right sides only at the embolic model induced by polyvinyl alchol particles (p<0.05). These changes were not detected in microscopic finding but could be identified in vital staining. CONCLUSION: Diffusion-weighted MR image can be used to detect early parenchymal change when the appropriate b-factor range was applied.
Acetone ; Animals ; Diffusion* ; Hypovolemia ; Models, Animal ; Models, Theoretical* ; Perfusion ; Polyvinyls ; Water

PURPOSE: To report the results of switching treatment to vascular endothelial growth factor (VEGF) Trap-Eye (aflibercept) in neovascular age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) refractory to anti-VEGF (ranibizumab and bevacizumab). METHODS: This is a retrospective study involving 32 eyes from 29 patients; 18 were cases of neovascular AMD and 14 were cases of PCV. The best-corrected visual acuity (BCVA) and central macular thickness (CMT) of spectral-domain optical coherence tomography were evaluated. RESULTS: BCVA and CMT improved from 0.58 to 0.55 (p = 0.005) and from 404 to 321 microm (p < 0.001), respectively, after switching to aflibercept. The 14 eyes that received 6 or more aflibercept injections remained stable at 0.81 to 0.81 and 321 to 327 microm (p = 1.0, 0.29), respectively, after 3 aflibercept injections. The 10 eyes that received 3 or more bevacizumab injections after 3 or more aflibercept injections worsened, from 0.44 to 0.47 and from 332 to 346 microm (p = 0.06, 0.05), respectively. The results showed similar improvement of BCVA and CMT in neovascular AMD and PCV. CONCLUSIONS: Aflibercept seems to be effective for improvement and maintenance of BCVA and CMT for neovascular AMD and PCV refractory to anti-VEGF. Switching from aflibercept back to bevacizumab treatment may not be a proper strategy.
Angiogenesis Inhibitors/administration & dosage ; Bevacizumab/administration & dosage ; Choroid/*blood supply ; Choroid Diseases/complications/diagnosis/*drug therapy ; Dose-Response Relationship, Drug ; Drug Therapy, Combination ; Female ; Follow-Up Studies ; Humans ; Intravitreal Injections ; Male ; Ranibizumab/administration & dosage ; Receptors, Vascular Endothelial Growth Factor/*administration & dosage ; Recombinant Fusion Proteins/*administration & dosage ; Retinal Neovascularization/complications/diagnosis/*drug therapy ; Retrospective Studies ; Tomography, Optical Coherence ; Treatment Outcome ; Vascular Endothelial Growth Factor A/*antagonists & inhibitors ; *Visual Acuity ; Wet Macular Degeneration/diagnosis/*drug therapy/etiology

In order to observe the pattern of a flow image on multisection MR imaging technique, a flow phantom experiment was preformed using a superconducting high filed 2.0 Tesla MRI scanner. The pattren of the first section images was homogeneous round at all flow velocities until the turbulence forming level. The patterns of the second section images,however,changed into a homogeneous round shape, a ring shape, a target shape, and a small round shape as the velocity increased. When scanned at velocities higher than the trubulence forming level, the images become distored and irregular, and eventually disappeared after the cut-off velocity. The homogeneous round image senn at the lower velocity levels in throught to be due to the overwhelming effects of fully managetized spins influxed into the imaging section during the prior repetition time(TR). Later in the higer velocity levels the effects of the partially saturated spins and fully magnetized spins influxed during the section transit time(TR/slice number) are added, and result in ring, target, and small round patterns in the second section image.
Magnetic Resonance Imaging*

PURPOSE: The authors experienced a case of orbital emphysema causing eye movement disorder following conjunctival tear without any orbital wall fractures after exposure to compressed air. CASE SUMMARY: A 28-year-old man's left periorbital area was injured while working with compressed air. There was marked lid swelling on the left side with palpable crepitus. The patient had an exotropia and hypertropia of the left eye. In addition, the extraocular movement of the left eye was restricted on upgaze without nausea and vomiting. On slit-lamp examination, conjunctival partial laceration and subconjunctival air bubbles adjacent to the conjunctival laceration could be seen. Orbital computed tomography showed air in the periorbital and retrobulbar region of the left eye and no evidence of orbital fracture. On examination 4 days after the primary repair of the conjunctival laceration, the patient completely recovered without any complication. CONCLUSIONS: Orbital emphysema following a conjunctival laceration caused by compressed air without any orbital wall fractures can cause restriction of eye movement.
Adult ; Compressed Air* ; Emphysema* ; Exotropia ; Eye Movements* ; Humans ; Lacerations ; Nausea ; Ocular Motility Disorders ; Orbit* ; Orbital Fractures* ; Strabismus ; Vomiting

Renal involvements of POEMS syndrome are not rare. In some reports, almost 50% of patients show proteinuria. There are some case reports of renal involvement in POEMS syndrome in Korea, but there are no reports about clinical features of renal involvement in POEMS syndrome in Korea and its frequency. We report a case of POEMS syndrome with nephropathy and clinical features of renal involvement in POEMS syndrome in Korea. The most frequent symptoms in POEMS syndrome in Korea were polyneuropathy, edema and ascites. Renal involvement was found in 40% of patients. If there were unknown cause of edema and renal failure when combined with polyneuropathy, considerations should be taken into patients for POEMS syndrome even though POEMS syndrome is very rare.
Ascites ; Edema ; Humans ; Korea* ; POEMS Syndrome* ; Polyneuropathies ; Proteinuria ; Renal Insufficiency

In vivo 31P NMR spectra were obtained in eight infant brain at 4.7T. Each phosphorus metabolite and its ratio were analyzed to evaluate the brain damage and maturity, and compared with the reported data obtained at the lower field strength. Measurement of T1 relaxation time at 4.7T was done in an infant and a cat brain in vivo. PCr/Pi and PCr/β-ATP ratio were used as a marker of brain damage. PME/PDE revealed higher values than those of the reported data obtained at the lower field strength and the difference was partly attributed to the long T1 relaxation time of PME rather than the brain immaturity. Although the resolution of the spectrum was improved at 4.7T, a long repetition time is recommended to minimize T1difference of phosphorus metabolites of brain at 4.7T.
Animals ; Brain* ; Cats ; Humans ; Infant ; Magnetic Resonance Spectroscopy* ; Phosphorus ; Relaxation

Patients with bile duct stones usually present with biliary pain, obstructive jaundice, ascending cholangitis, or pancreatitis. When endoscopic retrograde cholangiopancreatography (ERCP) is performed, bile duct stones are usually movable and thus easily detected. If a stone in the bile duct presents unusually, it may pose some diagnostic challenges. Recently, we experienced a case of an impacted distal common bile duct (CBD) stone mimicking a tumor which resulted in performing a pylorus-preserving pancreaticoduodenectomy in an asymptomatic 56-year-old man. On ERCP, an obstructing distal CBD lesion did not move even by doing brush cytology. Moreover, the result of brush cytology was positive for atypical cells. A major resective surgery performed after recovery from severe post-ERCP pancreatitis confirmed the diagnosis. Interestingly, this stone caused erosion with acute and chronic inflammation and fibrosis containing foci of mild epithelial dysplasia. We herein report an unusual manifestation of gallstone disease with a review of the literature.
Bile Ducts ; Cholangiopancreatography, Endoscopic Retrograde ; Cholangitis ; Common Bile Duct* ; Diagnosis ; Fibrosis ; Gallstones* ; Humans ; Inflammation ; Jaundice, Obstructive ; Middle Aged ; Pancreaticoduodenectomy ; Pancreatitis

OBJECTIVE: The aim of this study is to determine whether there is any difference in white matter (WM) integrity between Alzheimer's disease (AD) with metabolic syndrome (MetS) and without MetS. METHODS: Altogether, 30 subjects were finally recruited from the Memory Impairment Clinics of Pusan National University Hospital in Korea. All subjects (AD with MetS : n=15, matched AD without MetS for age, gender and year of education : n=15) were underwent 3-tesla magnetic resonance imaging scans of diffusion tensor imaging. RESULTS: The mean fractional anisotropy of the AD with MetS was lower (p<0.05) in right posterior corona radiate, right corticospinal tract and right superior longitudinal fasciculus than that of the AD without MetS. CONCLUSION: Our findings suggest that WM integrity damage.
Alzheimer Disease* ; Anisotropy ; Busan ; Diffusion Tensor Imaging ; Education ; Humans ; Korea ; Magnetic Resonance Imaging* ; Memory ; Pyramidal Tracts ; White Matter*

PURPOSE: This study was designed to evaluate early parenchymal changes of acute cerebral ischemia / infarct by using T2-weighted, diffusion-weighted, and calculated apparent diffusion coefficient (ADC) MR imaging. MATERIALS AND METHODS: The brain MR images were successfully obtained 30, 60, 90, 120, 150 and 180 minutes after intraarterial administration of Lipiodol (0.4 - 0.6 ml) into the common carotid artery in 10 of 11 cats (91%). T2-and diffusion-weighted images and ADC were analyzed and compared with histopathologic findings. RESULTS: High signal intensity on T2-weighted and diffusion-weighted images was found in one cerebral hemisphere 30 minutes after Lipiodol injection, which tended to increase with time until 3 hours. Subcortical white matter showed higher signal intensity than cortical gray matter since 30 minutes after embolization. ADC images showed decreased signal intensity in the embolized hemisphere, which tended to decrease until 3 hours. Microscopic findings of the area corresponding to the abnormal signal intensity on MR images revealed varying degrees of edema in the gray and white matters involved. CONCLUSION: It is suggested that Lipiodol can be used as a good embolic agent causing early ischemic changes in experimental models. In addition to T2-weighted images, diffusion-weighted and ADC images can provide the further informations in the evaluation of the early parenchymal changes of cerebral infarct.
Animals ; Brain ; Brain Ischemia ; Carotid Artery, Common ; Cats* ; Cerebrum ; Diffusion ; Edema ; Ethiodized Oil* ; Magnetic Resonance Imaging* ; Models, Theoretical

OBJECTIVES: Most studies of hippocampal metabolism(HM) in amnestic mild cognitive impairment(aMCI) gave inconsistent results. Our objective was to evaluate the effect of amyloid-beta(Aβ) status on hippocampal metabolism in aMCI.METHODS: Overall, 23 aMCI underwent three-dimensional magnetic resonance imaging(MRI), ¹⁸F-fluorodeoxyglucose-positron emission tomography(¹⁸FDG-PET) and ¹⁸F-Fluorbetaben amyloid positron emission tomography (amyloid-PET). According to Aβ status on amyloid PET, 23 aMCI were classified as either Aβ+aMCI(N=13) or Aβ−aMCI(N=10). The primary outcome was HM using ¹⁸FDG-PET and we investigate the difference on HM between Aβ+aMCI and Aβ−aMCI using analysis of variance(ANOVA) model, after controlling hippocampal volume.RESULTS: We found that HM was more decreased in Aβ+aMCI than Aβ−aMCI. This result was not changed after controlling hippocampal volume.CONCLUSION: Our findings suggest that Aβ+ is associated with decreased HM, regardless of hippocampal volume, in aMCI.
Amyloid ; Cognition Disorders ; Metabolism ; Pilot Projects ; Plaque, Amyloid ; Positron-Emission Tomography