Usefulness of Three Dimensional Proset MR Images for Diagnosis of Symptomatic L5-S1 Foraminal and Extraforaminal Stenosis

OBJECTIVE: To suggest a new useful diagnostic technique, principles of the selective excitation technique-magnetic resonance images (Proset-MRI), and to know the precise radiologic findings that can prove symptomatic foraminal and extraforaminal stenosis at L5-S1. METHODS: Nineteen patients with symptomatic L5-S1 stenosis were checked by Proset-MRI. Four patients were performed decompressive surgery and 15 patients were performed selective nerve root block (SNRB) at L5. The pain scale of patients was checked by Visual Analogue Scale (VAS) scores at the pre- and post-treatment state. RESULTS: Proset-MRI findings of patients with symptomatic stenosis are root swelling (RS) and indentation. The comparisons with VAS scores had a meaningful statistical result at each RS (p<0.01) and indentation (p<0.01). However, the findings of RS combined with indentation lacked statistical significance (p=0.0249). In addition, according to a comparison with the treatment modalities, reducing of VAS scores had statistical meaningful significance in decompressive surgery cases (p<0.01), and also in SNRB cases (p<0.01) after a 3-month follow-up period. CONCLUSION: The three dimensional Proset-MRI is very useful and sensitive technique to diagnose the symptomatic foraminal and extraforaminal stenosis at L5-S1.

Differentiation between Symptomatic and Asymptomatic Extraforaminal Stenosis in Lumbosacral Transitional Vertebra: Role of Three-Dimensional Magnetic Resonance Lumbosacral Radiculography

OBJECTIVE: To investigate the role of lumbosacral radiculography using 3-dimentional (3D) magnetic resonance (MR) rendering for diagnostic information of symptomatic extraforaminal stenosis in lumbosacral transitional vertebra. MATERIALS AND METHODS: The study population consisted of 18 patients with symptomatic (n = 10) and asymptomatic extraforaminal stenosis (n = 8) in lumbosacral transitional vertebra. Each patient underwent 3D coronal fast-field echo sequences with selective water excitation using the principles of the selective excitation technique (Proset imaging). Morphologic changes of the L5 nerve roots at the symptomatic and asymptomatic extraforaminal stenosis were evaluated on 3D MR rendered images of the lumbosacral spine. RESULTS: Ten cases with symptomatic extraforaminal stenosis showed hyperplasia and degenerative osteophytes of the sacral ala and/or osteophytes at the lateral margin of the L5 body. On 3D MR lumbosacral radiculography, indentation of the L5 nerve roots was found in two cases, while swelling of the nerve roots was seen in eight cases at the exiting nerve root. Eight cases with asymptomatic extraforaminal stenosis showed hyperplasia and degenerative osteophytes of the sacral ala and/or osteophytes at the lateral margin of the L5 body. Based on 3D MR lumbosacral radiculography, indentation or swelling of the L5 nerve roots was not found in any cases with asymptomatic extraforaminal stenosis. CONCLUSION: Results from 3D MR lumbosacral radiculography Indicate the indentation or swelling of the L5 nerve root in symptomatic extraforaminal stenosis. Based on these findings, 3D MR radiculography may be helpful in the diagnosis of the symptomatic extraforaminal stenosis with lumbosacral transitional vertebra.

Extensive demyelinating change in cerebrum after a total knee replacement: A case report / 대한마취과학회지

Demyelination is characterized by the loss of myelin with the preservation of axons. Demyelinating diseases can be classified into several categories: demyelination due to inflammation, viral infection, osmotic derangements and hypoxic ischemia. In particular, osmotic myelinolysis is representative, and is associated with hyperosmolality, hypokalemia or rapid correction of hyponatremia. Osmotic myelinolysis was reported to be associated with underlying conditions, such as alcoholism, diuretics and malnutrition. A 67-year-old woman with hypertension was scheduled to undergo both total knee replacements (TKR). She was observed to be lethargic with dysphagia and quadriplegia after the second TKR. She had been taking diuretics for a long time, and did not have an adequate amount of food intake due to patient controlled analgesia and a gastric ulcer after the first TKR. A laboratory examination revealed hypokalemia but normonatremia. T2 weighted-MRI revealed abnormal high signal intensity in the basal ganglia and periventricular area. This case was diagnosed with osmotic myelinolysis associated with hypokalemia without an apparent sodium imbalance.

Bilateral Medial Medullary Infarction Demonstrated by Diffusion-Weighted Imaging: Case Report / 영남의대학술지

A 78-year-old woman presented with weakness of the extremities, dysarthria, dizziness, and sensory impairment. Magnetic resonance imaging showed acute bilateral medial medullary infarction. Contrast enhanced magnetic resonance angiography demonstrated stenosis or occlusion of both intracranial vertebral arteries. We present a rare case of bilateral medullary infarction seen on diffusion-weighted imaging.

Quantitative Evaluation of the Corticospinal Tract Segmented by Using Co-registered Functional MRI and Diffusion Tensor Tractography

PURPOSE: The purpose of this study was to investigate the quantitative evaluation of the corticospinal tract (CST) at the multiple levels by using functional MRI (fMRI) co-registered to diffusion tensor tractography (DTT). MATERIALS AND METHODS: Ten normal subjects without any history of neurological disorder participated in this study. fMRI was performed at 1.5 T MR scanner using hand grasp-release movement paradigm. DTT was performed by using DtiStudio on the basis of fiber assignment continuous tracking algorithm (FACT). The seed region of interest (ROI) was drawn in the area of maximum fMRI activation during the motor task of hand grasp-release movement on a 2-D fractional anisotropy (FA) color map, and the target ROI was drawn in the cortiocospinal portion of anterior lower pons. We have drawn five ROIs for the measurement of FA and apparent diffusion coefficient (ADC) along the corona radiata (CR) down to the medulla. RESULTS: The contralateral primary sensorimotor cortex (SM1) was mainly found to be activated in all subjects. DTT showed that tracts originated from SM1 and ran to the medulla along the known pathway of the CST. In all subjects, FA values of the CST were higher at the level of the midbrain and posterior limb of internal capsule (PLIC) than the level of others. CONCLUSION: Our study showed that co-registered fMRI and DTT has elucidated the state of CST on 3-D and analyzed the quantitative values of FA and ADC at the multiple levels. We conclude that co-registered fMRI and DTT may be applied as a useful tool for clarifying and investigating the state of CST in the patients with brain injury.

MR Manifestations of the Brain in Neuropsychiatric Systemic Lupus Erythematosus Patients

PURPOSE: The primary goal of this study was to evaluate the MR findings of systemic lupus erythematosus (SLE) patients with neuropsychiatric symptoms. MATERIALS AND METHODS: The MR images of 38 patients with SLE were evaluated based on the presence of the following abnormal lesions: the locations of the abnormal signal intensity lesions in the white matter, infarctions, a small vessel vasculopathy, leukoencephalopathy, hemorrhage, abscess, and other lesions. RESULTS: The MR images showed an abnormality in 22 of 38 (58%) episodes. Abnormal signal intensities were noted in the subcortical and periventricular white matter in six cases, acute territorial infarctions in five cases, multiple small acute embolic infarctions in four cases and a brain abscess in two cases. A reversible posterior leukoencephalopathy was found in one case. In addition, another patient had vasogenic edema with focal central cytotoxic edema at the pons. The entire cerebral and corpus callosum volumes were significantly smaller in four patients with SLE as compared to the volumes in healthy control subjects. CONCLUSION: SLE may induce variable MR imaging findings of the CNS. Recognition of the variable findings is helpful for easy diagnosis and prompt treatment.

Diffusion Weighted MRI Patterns Caused by Acute Border Zone Infarction

PURPOSE: We investigated the causes and mechanisms driving acute border zone infarctions using diffusion-weighted imaging (DWI). MATERIALS AND METHODS: We analyzed DWI in 104 patients (male: 72 years, female: 32 years, age range: 44 to 84 years) with acute border zone infarction. The DWI patterns were classified as follows: pattern A- An acute border zone infarction combined with multiple small disseminated cortical infarctions, pattern B- An acute border zone infarction only. RESULTS: The most common cause of acute border zone infarctions was extracranial internal carotid artery (ICA) stenosis (45 cases, 43%). Other causes included middle cerebral artery stenosis (22 cases, 21%), intracranial ICA stenosis (14 cases, 13%), unknown, (12 cases 12%), iatrogenic (6 cases, 6%) and cardiogenic (5 cases, 5%), respectively. The most common pattern for DWI was pattern A (83 cases, 80%). We performed a transcranial Doppler in 7 of 75 cases (11%), and found at least 1 embolic pulse. CONCLUSION: The most common pattern of DWI for acute border zone infarctions was pattern A. We propose that the mechanisms driving acute border zone infarctions are emboli coupled with hypoperfusion.

MR Imaging of a Cerebello-Pontine Angle Epidermoid Cyst with a Malignant Transformation: Case Report

The malignant transformation of an epidermoid cyst can be discovered at the same time as a pre-existing epidermoid cyst, or during a follow-up examination after an incomplete excision. We describe a rare case of malignant transformation of a cerebello-pontine angle epidermoid cyst which extended into the middle cerebellar peduncle.

Subcutaneous Emphysema and Inflammation of the Neck after Tracheal Puncture by an Intubating Stylet / 영남의대학술지

Laryngo-tracheal perforation caused by the use of a stylet during tracheal intubation is a rare complication. We present a case of subcutaneous emphysema and connective tissue inflammation after tracheal intubation. The patient was a 41-year-old male undergoing general anesthesia for an appendectomy. The intubation was difficult during laryngoscopy (Cormack-Lehane Grade III). An assistant provided an endotracheal tube with a stylet inside while the laryngoscope was in place. During intubation, a short, dull sound was heard with a sudden loss of resistance after the distal tip of the endotracheal tube passed the rima glottis. A sonogram and computerized tomography revealed subcutaneous emphysema from the neck to the upper mediastinum and fluid collection between the trachea and the thyroid. This lesion appeared to have been caused by the protruded, loose stylet. Anesthesiologists should be aware of the damage a loose stylet protruding beyond the tip of the endotracheal tube can cause.

Endovascular Treatment of Traumatic Carotid- Jugular Fistula: Report of Two Cases

We report 2 patients with a traumatic carotid- jugular fistula. The first patient suffered a deep neck penetrating injury. The external carotid-jugular fistula was demonstrated by 3-dimension CT angiography (3D CTA) and digital subtraction angiography (DSA). The patient was treated with coil embolization. The second patient suffered a gun shot injury to the neck. 3D CTA and DSA revealed a common carotid-jugular fistula and a pseudoaneurysm. The common carotid-jugular fistula was treated with coil embolization in the fistula and the pseudoaneurysm was treated with stent assisted coil embolization.

In Vivo and In Vitro Studies of the Steady State Free Precession-Diffusion-Weighted MR Imagings on Low b-value: Validation and Application to Bone Marrow Pathology / 영남의대학술지

PURPOSE: The purpose of this study was a phantom study to measure the diffusion properties of water molecules by steady-state free precession diffusion-weighted imaging (SSFP-DWI) with a low b-value and to determine if this sequence might be useful for application to the evaluation of bone marrow pathology. MATERIALS AND METHODS: 1. The phantom study: A phantom study using two diffusion weighted sequences for the evaluation of the diffusion coefficient was performed. Three water-containing cylinders at different temperatures were designed: phantom A was 3degrees C, B was 23degrees C and C was 63degrees C. Both SSFP and echo planar imaging (EPI) sequences (b-value: 1000 s/mm2) were performed for comparison of the diffusion properties. The Signal to noise ratios (SNR) and apparent diffusion coefficient (ADC) values of the three phantoms using each diffusion-weighted sequence were assessed. 2. The Clinical study: SSFP-DWI was performed in 28 patients [sacral insufficiency fractures (10), osteoporotic lumbar compression fractures (10), malignant compression fractures (8)]. To measure the ADC maps, a diffusion-weighted single shot stimulated echo-acquisition mode sequence (650s/ mm2) was obtained using the same 1.5-T MR imager RESULTS: For the phantom study, the signal intensity on the SSFP as well as the classic EPI-based DWI was decreased as the temperature increased in phantom A to C. The ADC values of the phantoms on EPI-DWI were 0.13x10(-3) mm2/s in phantom A, 0.22x10(-3) mm2/s in B and 0.37x10(-3) mm2/s. in C. The SSFP can be regarded as a DWI sequence in view of the series of signal decreases. CONCLUSION: Bone marrow pathologies with different diffusion coefficients were evaluated by SSFP-DWI. All benign fractures were hypointense compared to the adjacent normal bone marrow where as the malignant fractures were hyperintense compared to the adjacent normal bone marrow.

Two Cases of Metronidazole-induced Encephalopathy / 대한소화기학회지

Metronidazole is a 5-nitroimidazole compound known as an antimicrobial agent widely used for the treatment of protozoal infection, anaerobic infection, Helicobacter pylori infection and hepatic encephalopathy. It may produce a number of neurologic side effects including peripheral neuropathy, seizure, encephalopathy, ataxic gait and dysarthritic speech. There have been ten or more reports of metronidazole-induced encephalopathy in the literatures including a few reports of brain imaging changes by magnetic resonance images (MRI). However, none of the case of metronidazole-induced encephalopathy in patients with hepatic encephalopathy has been reported yet. Recently, we experienced two cases of metronidazole-induced encephalopathy in patients with liver cirrhosis caused by chronic hepatitis B, which were diagnosed by brain MRI and MR spectroscopy. In this report, we present 2 cases of metronidazole-induced encephalopathy with MR imaging and MR spectroscopic changes including follow- up imaging performed after the discontinuation of the metronidazole with a review of the literatures.

Evidence of Cortical Reorganization in a Monoparetic Patient with Cerebral Palsy Detected by Combined Functional MRI and TMS / 영남의대학술지

The motor recovery mechanism of a 21-year-old male monoparetic patient with cerebral palsy, who had complained of a mild weakness on his right hand since infancy, was examined using functional Magnetic Resonance Imaging (fMRI) and Transcranial Magnetic Stimulation (TMS). The patient showed mild motor impairment on the right hand. MRI located the main lesion on the left precentral knob of the brain. fMRI was performed on this patient as well as 8 control subjects using the Blood Oxygen Level Dependent technique at 1.5 T with a standard head coil. The motor activation task consisted of finger flexion- extension exercises at 1 Hz cycles. TMS was carried out using a round coil. The anterior portion of the coil was applied tangentially to the scalp at a 1.0 cm separation. Magnetic stimulation was carried out with the maximal output. The Motor Evoked Potentials (MEPs) from both Abductor Pollicis Brevis muscles (APB) were obtained simultaneously. fMRI revealed that the unaffected (right) primary sensori-motor cortex (SM1), which was centered on precentral knob, was activated by the hand movements of the control subjects as well as by the unaffected (left) hand movements of the patient. However, the affected (right) hand movements of the patient activated the medial portion of the injured precentral knob of the left SM1. The optimal scalp site for the affected (right) APB was located at 1 cm medial to that of the unaffected (left) APB. When the optimal scalp site was stimulated, the MEP characteristics from the affected (right) APB showed a delayed latency, lower amplitude, and a distorted figure compared with that of the unaffected (left) APB. Therefore, the motor function of the affected (right) hand was shown to be reorganized in the medial portion of the injured precentral knob.

High-Resolusion Magnetic Resonance Imaging of Carotid Atherosclerotic Plaque / 영남의대학술지

A thromboembolic stroke is believed to be precipitated by a rupture of vulnerable atheromatous plaques. Until recently the assessment of a further risk of stroke in high-risk patients in whom atherosclerosis has presented with a transient ischaemic attack (TIA), has been confined to a quantitative assessment of the luminal patency of the internal carotid artery. These traditional stratification parameters are no longer believed to be the most accurate predictors of a thrombo-embolism. This is because the process of vessel wall remodeling can maintain a luminal patency, and consequently, quite large friable plaques may remain unidentified. Accordingly, there is a need for an improved risk assessment. The fibrous cap of a vulnerable plaque is thinner, and an intraplaque hemorrhage and inflammation can occur during the development of atherosclerotic plaque. Several imaging methods for identifying vulnerable plaques have been developed. Recently, high resolution magnetic resonance (MR) imaging has emerged as an accurate non-invasive tool that can characterize the carotid plaque components in vivo. A High resolution carotid magnetic resonance is capable of distinguishing an intact, thick fibrous cap from a thin and ruptured cap in carotid plaque. In addition, a plaque MR can identify the active inflammation and detect a hemorrhage. High resolution carotid MR imaging is a valuable noninvasive method for quantifying the plaque components and identifying vulnerable plaque.

The Diagnosis of Motor Tract Disruption in Thalamic and Putaminal Hemorrhage using Diffusion Tensor MRI and Its Relation with Motor Recovery

OBJECTIVE: The purpose of this study is to prove and quantify motor tract disruption and to correlate with motor weakness and its recovery in thalamic and putaminal hemorrhage using diffusion tensor magnetic resonance(MR) image. METHODS: We studied 24 patients with thalamic and putaminal hemorrhage with motor weakness who did not underwent surgery(hematoma volume 75.0%)and compared means of motor power at each time. RESULTS: The means of FA ratio were 42.5% in group A, 63.0% in group B and 88.2% in group C. The means of motor power were 1.1, 2.3 and 3.7 at initial. After 6 months the means of motor power were 3.0, 4.0 and 4.5. The group of lower FA ratio had more severe motor weakness and showed worse motor recovery clinically than the group of higher FA ratio(P < 0.01). Though patients had severe motor weakness initially, the patients with high FA ratio showed good recovery. CONCLUSION: In thalamic and putaminal hemorrhage, diffusion tensor MR image can prove the degree of motor tract damage and predict the degree of motor recovery.

Evidence of Microstructural Abnormality on Descending Motor Pathway in Cerebral Plasied Children with Periventricular Leukomalacia: Diffusion Tensor MRI Study

OBJECTIVE: Using diffusion tensor MRI (DTI), to investigate the microstructural abnormality of corticospinal tract in the cerebral palsied children with periventricular leukomalacia on conventional MRI and to recognize the clinical usefulness of DTI. METHOD: Seven patients were studied. DTI was peformed using 1.5T MR scanner (Vision Plus, Siemens, Erlangen, Germany) and fractional anisotropies of corona radiata, posterior limbs of internal capsules, and cerebral peduncles of midbrain in both hemisphere were calculated. RESULTS: The fractional anisotropy was significantly decreased in all corona radiata, posterior limbs of internal capsules, cerebral peduncles of midbrain in six patients except one hemiplegic patient, compared with that of control group. In in the hemiplegic patient, the fractional anisotropy was reduced only in affected hemisphere. In addition, the fractional anisotropy tended to be also increased as gross motor function measure (GMFM) score was increased. CONCLUSION: We believe that DTI may be efficient in evaluating microstructural abnormality on the motor pathway of brain and helpful in providing prognosis of clinical findings in cerebral palsied children with periventricular leukomalacia.

Idiopathic Hypertrophic Cranial Pachymeningitis: Case Report

Idiopathic hypertrohpic cranial pachymeningitis is rare, and is essentially a diagnosis of exclusion. A 53-year-old man presented with headache and visual loss in the right eye, first experienced a month earlier. MR images depicted a mass in the right cavernous sinus. At T1-weighted imaging, both the mass and the thickened dura mater present in both fromted lobes were isointense, while at while T2-weighted imaging, the signal intensity of both the mass and the dura mater was low. After the injection of contrast medium, pachymeningeal enhancement was observed. We report the radiologic findings in a case of idiopathic hypertrophic cranial pachymeningitis, confirmed surgically and pathologically.

The Usefulness of Diffusion-weighted MR Imaging for Differentiation between Degenerative Spines and Infectious Spondylitis

PURPOSE: The differential diagnosis between Modic type I degenerative spine and infectious spondylitis sometimes is difficult, because the affected bone marrows in both disease show similar signal intensity on conventional MR imaging. We evaluate the usefulness of diffusion-wighted MR imaging for differential diagnosis between Modic type I degenerative spine and infectious spondylitis. MATERIALS AND METHODS: The spin-echo and diffusion-weighted MR images of eight patients with Modic type I degenerative spines and 14 patients with infectious spondylitis diagnosed by clinical findings or CTguided biopsies were analyzed. The diffusion-weighted imaging sequence was based on reversed fast imaging with steady-state precession (PSIF). Signal intensity changes of the vertebral bone marrow on conventional spin-echo and diffusion-weighted MR imaging were compared between degenerative spine and infectious spondylitis. RESULTS: On T1-weighted images, the affeted bone marrow in both disease showed hypointense signals. On T2-weighted images, all of type I degenerative spine and 11 of infectious spondylitis showed hyperintensity, and three of infectious spondylitis showed heterogeneous mixed signal intensity. On diffusionweighted MR images, all of type I degenerative spine were hypointense with peripheral high signal intensity to normal vertebral body, but infectious spondylitis was hyperintense (n=11) and hypointense (n=3). CONCLUSION: Diffusion-weighted MR imaging is useful to differentiate Modic type I degenerative spine from infectious spondylitis. On diffusion-weighted images, the high singal intensity of bone marrow suggests infectious spondylitis, whereas the low signal intensity of bone marrow with peripheral focal high signal intensity suggests type I degenerative spine.

Meningeal Hemangiopericytoma in a Newborn: A Case Report

Several, but not many, cases of congenital meningeal hemangiopericytoma have been described to date. Herein, a case of meningeal hemangiopericytoma in a newborn is described. The patient was a 2-week-old boy with expanded fontanelles and frequent vomiting. A 5 cm sized mass was found in the left temporo-parietal lobe, which was well circumscribed and lobulated. Histologically the tumor was compatible with anaplastic (malignant) hemangiopericytoma, which showed pleomorphic nuclei, frequent mitotic figures and extensive hemorrhagic necrosis. The tumor cells were immunoreactive for vimentin, but negative for CD34, desmin and S-100 protein. Differential diagnosis for meningeal hemangiopericytoma was discussed, and the fact that meningeal hemangiopericytoma might have occurred congenitally was emphasized.

Comparison of Clinical Outcomes and Natural Morphologic Changes between Sequestered and Large Central Extruded Disc Herniations

A prospective and longitudinal investigation concerning clinical outcomes and morphologic changes of large lumbar disc herniations by MR imaging. To compare the clinical outcomes and the natural morphologic changes of between sequestered and large central extruded disc herniations. The spontaneous disappearance or diminution of large herniated lumbar discs in the spinal canal is known. Poor clinical outcome and small changes of herniated discs have been shown for large central extruded disc herniations with conservative treatment. The study population consisted of 22 patients with sequestration and a large central as extrusion established by an MR imaging study. Seventeen (11 patients with sequestration, and 6 patients with a large central extrusion) patients underwent a follow-up MR imaging study. The size of the herniated disc was measured on serial MR imaging studies, and the changes in size were classified into four categories. Clinical evaluations were also performed using a visual analogue scale (VAS), the Oswestry lowback pain disability questionnaire, the straight leg raising test (SLRT) and so forth. Both the sequestered and large central extruded disc herniations showed a successful clinical outcome after conservative treatment in 17 of 22 patients (77%) in total: 11 of 13 patients (85%) with sequestered disc herniations, and 6 of 9 patients (67%) with large central extruded disc herniations. VAS and Oswestry disability scoring showed a greater change in the group with sequestration than in the group with large central extrusions. In the group with sequestration, seven patients reported the disappearance of herniated disc materials, and four patients showed a marked decrease in the size of their herniated discs in follow-up MR images. However, in the group with large central extrusions, only two patients showed a decrease in the size of their herniated discs. Large central extruded disc herniations can be treated successfully by conservative treatment. Outcomes seemed to be as good as or slightly inferior to those of sequestered disc herniations. However, a greater morphologic decrease in the herniated discs occurred more frequently for sequestered disc herniations than for large central extruded disc herniations.