Detection of acute thalamo-mesencephalic infarction: diffusion abnormality precedes T2 hyperintensity

OBJECTIVE: To examine the time course of signal changes in diffusion-weighted magnetic resonance imaging (DW-MRI) and T2-weighted MRI in a case of cerebral infarction in the posterior circulation territory. MATERIALS AND METHODS: Diffusion- and T2-weighted MRI and comparison of signal changes in these sequences at 4 h, 1 day and 4 days after the onset of clinical symptoms caused by acute thalamo-mesencephalic infarction. RESULTS: Four hours after the onset of symptoms, signal changes in DW-MRI revealed an infarction in the territory of the posterior perforating thalamic artery, whereas no signal changes were detected in T2-weighted MRI. In follow-up MRI 1 and 4 days after infarction, however, a marked hyperintensity matching the location of the diffusion deficit could be identified in T2 images. CONCLUSION: Signal changes in DW-MRI precede T2 hyperintensity after infarction in the posterior circulation territory after hemispheric infarction.     

An MR image of spinal cord sarcoidosis

We present a case of spinal cord sarcoidosis with a unique magnetic resonance imaging (MRI) finding. MRI of the cervical spine revealed an unusual lesion of low signal intensity on T2-weighted image at the core of the lesion surrounded by high signal intensity. T1-weighted gadolinium enhanced image showed a high signal at the core lesion. Low signal intensity on T2-weighted image in the case was suggested to be due to hemosiderin deposition. Steroid therapy dramatically improved clinical symptoms with a marked reduction of peripheral T2 high intensity area and the core lesion size detected by gadolinium enhancement.     

Magnetic Resonance Imaging of the Thalamus following Cryothalamotomy for Parkinson's Disease and Dystonia

Magnetic resonance imaging (MRI) was performed on 3 patients after cryothalamotomy, one of whom had bilateral cryothalamotomies. The time between surgery and MRI ranged from 23 days to 6.5 months. Images made 3 to 4 weeks after surgery showed a lesion of high signal intensity on both T1-weighted and T2-weighted images, and an additional central area of low signal intensity on T1-weighted images. Images obtained at 2, 4, and 6.5 months after surgery showed smaller lesions with low signal intensity on T1-weighted and T2-weighted images, a pattern consistent with resolving hematoma after cryothalamotomy.     

MRI and CT findings in Krabbe disease

The progression and characteristics of magnetic resonance imaging (MRI) and computed tomographic (CT) findings in 3 patients with infantile Krabbe disease (i.e., globoid cell leukodystrophy or galactocerebroside beta-galactosidase deficiency) are reported. We obtained initial CT and MRI studies when patients demonstrated hyperirritability and hypertonicity. The following results facilitated early diagnoses: increased density in the thalami, corona radiata, and cerebellar cortex on CT and plaque-like, high signal intensity in the periventricular region and cerebellar white matter on MRI T2-weighted images. After severe motor and mental deterioration and spasticity had developed, progressive brain atrophy, low density in the white matter, and calcification-like, symmetric, punctate high-density areas in the corona radiata were evident on CT and high signal intensity in T2-weighted images and low signal intensity in T1-weighted images in the white matter were present on MRI. In particular, linear patterns were observed in the centrum semiovale on MRI.     

Asymptomatic self-limiting white matter lesions in the chronic phase of herpes simplex encephalitis

We report a 9-month-old girl with herpes simplex encephalitis. T(2)-weighted magnetic resonance imaging (MRI) on the 8th day of illness showed increased signal intensity in the gray and white matter of the bilateral lobes, especially the right temporo-parietal lobe. High voltage slow waves were recorded in the right parieto-occipital region on electroencephalography. She was discharged on the 34th day of illness without sequelae. On discharge, the high signal intensity on MRI had improved and the abnormal slow waves on electroencephalography had disappeared. At 4 months after the onset of illness, MRI revealed decreased signal intensities in T(1)-weighted images and increased signal intensities in T(2)-weighted images in the periventricular white matter adjacent to the posterior horns of the lateral ventricles. The white matter lesions had expanded at 9 months after the onset of illness. At 14 months after the onset of illness, the white matter lesions were reduced in size, and at 2 years after the onset of illness, they had completely disappeared. During 2 years follow-up after discharge, however, there were no neurological abnormalities corresponding to the lesions and her psychomotor development was normal. Although the mechanism underlying these white matter lesions had not been elucidated, an immune-mediated complication such as edema or demyelination is suspected. Repeat MRI studies over a long period are necessary to follow up a patient with herpes simplex encephalitis.     

Clinical and imaging findings in patients with aggressive spinal hemangioma requiring surgical treatment

Vertebral hemangiomas (VHs) are frequently asymptomatic lesions found incidentally during investigations for other spinal problems. Symptomatic VHs are less common, and there are few reports of compressive VHs in the literature. VHs with aggressive behavior present with low signal intensity on T1-weighted and high signal intensity on T2-weighted MRI. We present a case series of four patients with compressive VH, all of whom were neurologically compromised. Each of the four patients underwent preoperative arterial embolization followed by surgical treatment of their VHs. All patients recovered normal motor function after surgery. At follow-up (average 53 months), one patient had a recurrent tumor requiring reoperation and radiotherapy. Although it is rare, aggressive VH can be a devastating condition. Total surgical resection or subtotal resection with radiotherapy may be warranted.     

Sequential magnetic resonance imaging and neurophysiological studies in a patient with inferior spinal cord infarction]

A 66-year-old woman suddenly developed anterior spinal artery syndrome with complete flaccid paraplegia, superficial sensory disturbance caudally to the L5 dermatome level with preservation of deep sensation, incontinence, and absent deep tendon reflexes in both legs. An MRI of the whole spine and an analysis of the CSF 4 hours after onset were normal. The electrophysiological study showed an absence of F wave on the posterior tibial nerve stimulation on admission, while the peripheral nerve conduction velocities and amplitudes of upper and lower limbs were normal. T2-weighted MRI 4 days after onset demonstrated an area of high signal intensity in the gray and white matters of the epiconus and conus medullaris, and T1-weighted MRI showed the swelling. Three weeks later, F wave became evoked nd the high signal areas on axial T2-weighted MRI were localized in the bilateral anterior horns of the gray matter. T1-weighted MRIs after an administration of Gd-DTPA 3 and 7 weeks after onset demonstrated an enhancement of the ventral roots of the lumbar nerves and cauda equina, while the enhancements disappeared 8 months after onset. The patient was finally able to walk independently over 10 meter. An absent F wave was an only positive finding at the hyperacute (hours after onset) stage of the spinal cord infarction.     

Magnetic resonance imaging of the hypothalamic-neurohypophyseal system

Magnetic resonance imaging (MRI) is a revolutionary advance in diagnostic imaging of the hypothalamic-neurohypophyseal system (HNS). The detailed anatomy of the sellar and parasellar region is clearly visible using MRI, because it has no bony artifacts and multidirectional capability. The posterior lobe of the pituitary gland displays a characteristic bright signal on the MR T1-weighted image (T1WI), and is distinctly separated from the anterior lobe. The bright signal is absent in patients with central diabetes insipidus, and is thought to reflect normal vasopressin storage in the posterior lobe. The signal intensity ratio of the posterior lobe to the pons on T1WI is strongly correlated with vasopressin content in the posterior lobe. In addition to the morphological evaluation, MRI provides unique information concerning the function of the HNS. The MRI findings of the HNS (normal condition, central diabetes insipidus, a depleted posterior lobe, an ectopic posterior lobe, and a damming-up phenomenon of the neurosecretory vesicles in the pituitary stalk) are demonstrated in this article.     

Magnetic resonance imaging in subacute combined degeneration of the spinal cord

We describe the magnetic resonance imaging (MRI) abnormalities in a patient with subacute combined degeneration of the spinal cord (vitamin B12-deficient myelopathy). T2-weighted images revealed symmetric, high signal abnormalities in the posterior columns of the cervical cord, which resolved following recovery from the disease. Recognition of this MRI pattern is important because this is likely to represent an early, potentially reversible stage of the disease.     

A case of spinal cord sarcoidosis with interesting MRI findings]

A case of spinal cord sarcoidosis was reported with special reference to MRI findings. A 15-year-old man was admitted to our hospital because of gait disturbance for last six months. Neurological examination on admission showed spastic paraparesis and posterior column signs. MRI of the cervical spinal cord revealed diffuse swelling and low intensity signal in T1-weighted sequences, diffuse high intensity signal in T2-weighted, and multiple micro-nodular lesion in Gd-DTPA enhanced T1-weighted. At first multiple sclerosis was suspected, although the data of cerebrospinal fluid was not suggestive. Four weeks after admission general fatigue, fever, cough, and headache appeared and the neurological symptoms got worse. Chest film and CT revealed diffuse small nodular shadows in the lung field. Abdominal ultrasonography and CT showed hepatosplenomegaly. The general condition became worse in spite of antibiotic and antituberculotic drug therapy, but remitted spontaneously in four weeks. MRI findings also exacerbated and improved during the same period, being compatible with neurological manifestations. The diagnosis of sarcoidosis was made by transbronchial lung biopsy which revealed sarcoid granuloma. Multiple small nodules on Gd-DTPA enhanced T1-weighted MRI had not been reported in patient with spinal cord sarcoidosis.     

MRI in vitamin B12 deficiency myelopathy

BACKGROUND: Little is known about vitamin B12 deficiency myelopathy's magnetic resonance imaging (MRI) manifestations and their relationship to the onset, evolution, and resolution of neurologic signs and symptoms. METHODS: We present a case and review eleven additional reported cases of subacute combined degeneration of the spinal cord detected by MRI. RESULTS: Our patient had increased T2-weighted signal and gadolinium contrast enhancement of the posterior columns in the cervical and thoracic regions and enhancement of the lateral columns in the high cervical region. This is a case with imaging evidence for lateral column lesions. Two prior reports have shown posterior column enhancement. T1-weighted images may show decreased signal in the posterior columns and sometimes demonstrate reversible spinal cord swelling. MRI abnormalities typically improve after vitamin replacement therapy. However, clinical signs may persist despite resolution of imaging abnormalities, and these abnormalities do not always resolve completely. In addition, symptoms may precede the imaging abnormality. CONCLUSIONS: Vitamin B12 deficiency may produce an increased T2-weighted signal, decreased T1-weighted signal, and contrast enhancement of the posterior and lateral columns of the spinal cord, mainly of the cervical and upper thoracic segments. Because the symptoms may precede any imaging abnormality, it is clear that spinal cord MRI may not be a highly sensitive, early test for subacute combined degeneration.     

An MR image of spinal cord sarcoidosis

Abstract

We present a case of spinal cord sarcoidosis with a unique magnetic resonance imaging (MRI) finding. MRI of the cervical spine revealed an unusual lesion of low signal intensity on T2-weighted image at the core of the lesion surrounded by high signal intensity. Tl-weighted gadolinium enhanced image showed a high signal at the core lesion. Low signal intensity on T2-weighted image in the case was suggested to be due to hemosiderin deposition. Steroid therapy dramatically improved clinical symptoms with a marked reduction of peripheral T2 high intensity area and the core lesion size detected by gadolinium enhancement. [Neurol Res 1999; 21: 755-757]     

A meta-analysis showing that high signal intensity on T2-weighted MRI is associated with poor prognosis for patients with cervical spondylotic myelopathy

We used PubMed, Medline, and EMBASE to conduct a meta-analysis to determine the significance of high signal intensity on T2-weighted MRI for predicting postoperative prognosis in patients with cervical spondylotic myelopathy (CSM). Although patients with CSM with high signal intensity on T2-weighted MRI usually had a poor prognosis even after undergoing surgery, some researchers have argued recently that high-intensity signals are not associated with postoperative prognosis. Data consistent with the inclusion criteria of this study were cited for meta-analysis using Review Manager 5 Software. The postoperative recovery ratio specified by the Japanese Orthopedic Association (JOA) was assessed using the weighted mean difference (WMD) method. Five articles (one prospective; four retrospective) involving 309 patients with CSM were included. The aggregate WMD with regard to the postoperative JOA recovery ratio between the T2-weighted high signal intensity positive (+) group and the T2-weighted high signal intensity negative (-) group was -6.56, and the 95% confidence interval (CI) was -12.15 to -0.97 (p=0.02). Thus, we concluded that in patients with CSM, the postoperative JOA recovery ratio in the T2-weighted (+) group was lower than that in the T2-weighted (-) group.     

A case of spinal dural AVF treated by endovascular embolization]

Here we report a case of spinal dural arteriovenous fistula(AVF) treated by endovascular embolization. A 58-year-old female presented with progressive intermittent claudication and numbness of the lower extremities. MRI showed swelling of the spinal cord with intramedullary high signal intensity on T2-weighted image and intramedullary enhancement, suggested spinal cord myelopathy. Myelography demonstrated the dilated serpentine vessels in the subarachnoid space and focal filling defect. Angiography showed spinal dural AVF fed by bilateral lateral sacral artery. The draining vein was posterior spinal vein. Endovascular embolization using liquid material was performed under general anesthesia. The injection of glue included the distal feeding artery, the shunt itself and the initial part of draining vein. A complete cure was achieved, with a normal postoperative angiogram. MRI returned to normal with complete disappearance of T2 high signal, cord enlargement and enhancement by contrast medium. It was suggested that venous congestion induced the transient spinal ischemia, manifested as intermittent claudication. Endovascular embolization using liquid material was safe and quite effective for spinal dural AVF.     

Laminar cortical necrosis in adrenal crisis: sequential changes on MRI

We describe the serial magnetic resonance imaging (MRI) findings in a six-year-old girl with congenital adrenal hyperplasia, who presented with seizures and unconsciousness during a hypoadrenal crisis. Initial neuroimaging revealed the presence of brain edema with high signal changes in the fronto-parietal cortex on diffusion-weighted MRI. The brain edema worsened four days into admission, and by day 14 low-density areas were seen over the frontal lobes bilaterally using computed tomography (CT). Follow-up MRI at between one and two months of admission revealed extensive white matter lesions with high intensity on T2-weighted images (T2WI) and fluid-attenuated inversion recovery (FLAIR) images, which extended into deep cortical layers. Additionally, linear lesions with high signal change on T1-weighted imaging developed in the superficial cortical layers, with frontal predominance. This layer appeared isointense on T2WI and high intensity on FLAIR images, suggesting laminar cortical necrosis. Two months later, linear, cavitary lesions appeared in the middle cortical layers between the aforementioned superficial laminar abnormality and deep cortex/white matter lesions. The high-intensity signals in the deep cortical layers remained contiguous with the white matter lesions. This unique type of multi-layered cortical lesion may have resulted from a complex combination of hypoglycemia and hypoxia/ischemia in the setting of adrenal insufficiency.     

Significance of increased signal intensity on MRI in prognosis after surgical intervention for cervical spondylotic myelopathy

We aimed to examine whether increased signal intensity (ISI) on T2-weighted MRI can be used to predict the surgical outcome of patients with cervical spondylotic myelopathy (CSM). ISI on T2-weighted MRI are frequently observed but the relevance of this finding remains controversial in patients with CSM. Between September 2007 and February 2009, 52 patients with CSM who underwent surgery were studied prospectively. Preoperative and postoperative functional status was evaluated using the modified Japanese Orthopaedic Association (JOA) scoring system, and the recovery rate was calculated using the Hirabayashi method. An MRI was performed on all patients. For those with ISI on T2-weighted MRI, the ratio of the signal intensity on T2-weighted to T1-weighted MRI (T2:T1 ratio) at the same spinal cord level and of similar area was calculated. Although the clinical outcome of all patients had improved at final follow-up, there was a significant difference between patients with ISI and those without ISI in age, duration of symptoms, preoperative and postoperative JOA scores, and recovery rate. The preoperative and postoperative JOA scores and the recovery rate differed significantly (p < 0.05) between the three groups: patients without a T2-weighted ISI, and those with different levels of a T2:T1 ratio. Patients with an ISI usually had a low preoperative JOA score and experienced less improvement in neurologic function after surgery. The T2:T1 ratio can be used to help predict surgical outcomes.     

Repeated hyperglycemic hemichorea in a patient with venous angioma in the putamen]

We report a case of an 81-year-old diabetic woman who had three episodes of choreic involuntary movement in the left extremities. Brain CT revealed faintly increased density in the right putamen. On MRI performed 28 days after onset of the left hemichorea, the right putamen showed increased signal intensity on T1-weighted images and the so-called "medusa-like appearance" of medullary venous drainage into the thalamostriate vein on enhanced T1-weighted images. These findings indicated petechial hemorrhage of the right putamen from a venous angioma. We hypothesize that this hemorrhagic change due to a venous malformation in the basal ganglia may induce involuntary movements in diabetic patients during severe hyperglycemia.     

Diagnosis of cerebral venous thrombosis with echo-planar T2*-weighted magnetic resonance imaging

BACKGROUND: Magnetic resonance (MR) signal changes suggestive of cerebral venous thrombosis (CVT) on T1- and T2-weighted images may be subtle and their identification requires a high degree of suspicion. Magnetic resonance venography remains essential for definitive diagnosis. Recent reports have shown that T2(*)-weighted MR sequence is more sensitive than T1-weighted, T2-weighted, and fluid-attenuated inversion recovery (FLAIR) images in detecting subarachnoid and intracerebral hemorrhages, both of which can be seen in association with CVT. The value of T2*-weighted magnetic resonance imaging (MRI) in diagnosing CVT has not been well studied. OBJECTIVES: To investigate and describe T2*(susceptibility-weighted) MRI findings in 5 patients with CVT. METHODS: We reviewed our stroke database from May 1, 1997, through May 31, 2001. The diagnosis of CVT was made in 6 patients, 5 had an MRI with T2* sequence. We examined T2*/susceptibility-weighted images for these 5 patients to determine their ability, relative to T1-weighted, T2-weighted, and FLAIR sequences, to detect CVT. RESULTS: On T2*-weighted images, we were able to detect areas of hypointensities in the affected veins and/or sinuses in all 5 patients. Thrombosed veins and/or sinuses were more easily seen on T2*-weighted images than on any other MR sequence. The T2* sequence also allowed visualization of associated hemorrhagic venous infarcts, which were considerably less obvious on other MR sequences. CONCLUSIONS: The T2*-weighted MR sequence can be useful in rapid detection of CVT and may enable the diagnosis to be made prior to MR venography. This is particularly important in clinically unsuspected patients, in whom MR venography is rarely obtained.     

Idiopathic Hypertrophic Spinal Pachymeningitis : Report of Two Cases and Review of the Literature

Idiopathic hypertrophic spinal pachymeningitis (IHSP) is a rare inflammatory disease characterized by hypertrophic inflammation of the dura mater and various clinical courses that are from myelopathy. Although many associated diseases have been suggested, the etiology of IHSP is not well understood. The ideal treatment is controversial. In the first case, a 55-year-old woman presented back pain, progressive paraparesis, both leg numbness, and voiding difficulty. Initial magnetic resonance imaging (MRI) demonstrated an anterior epidural mass lesion involving from C6 to mid-thoracic spine area with low signal intensity on T1 and T2 weighted images. We performed decompressive laminectomy and lesional biopsy. After operation, she was subsequently treated with steroid and could walk unaided. In the second case, a 45-year-old woman presented with fever and quadriplegia after a spine fusion operation due to lumbar spinal stenosis and degenerative herniated lumbar disc. Initial MRI showed anterior and posterior epidural mass lesion from foramen magnum to C4 level. She underwent decompressive laminectomy and durotomy followed by steroid therapy. However, her conditions deteriorated gradually and medical complications occurred. In our cases, etiology was not found despite through investigations. Initial MRI showed dural thickening with mixed signal intensity on T1- and T2-weighted images. Pathologic examination revealed chronic nonspecific inflammation in both patients. Although one patient developed several complications, the other showed slow improvement of neurological symptoms with decompressive surgery and steroid therapy. In case of chronic compressive myelopathy due to the dural hypertrophic change, decompressive surgery such as laminectomy or laminoplasty may be helpful as well as postoperative steroid therapy.     

Deep cerebral venous thrombosis: a report of three cases and review of the literature]

Three cases of cerebral deep venous thrombosis (CDVT) were reported with review of the literature. A 47-year-old female had taken estrogen-derived drug. The other two patients had no specific past history. On MRI, T2-weighted and fluid-attenuated inversion recovery (FLAIR) images showed high signal intensity lesions at basal ganglia and thalamus. Diffusion-weighted image (DWI) detected only slightly high signal spots but apparent diffusion coefficient (ADC) images indicated mild increases of the ADC value. MR venogram and cerebral angiogram revealed obliteration of internal cerebral veins, great vein of Galen, and straight sinus. The two severely impaired patients received systemic heparinization, in which one patient preceded percutaneous transvenous angioplasty of straight sinus. One patient suffered cognitive disturbance and the other two patients fully recovered from their illness. The high signal intensity lesions on both T2-weighted image and FLAIR image disappeared and deep cerebral veins reappeared. The diagnosis of CDVT based on clinical symptoms is not simple but modern technology of MRI is very useful for diagnosis of CDVT. Once CDVT is detected, appropriate therapy should be started as soon as possible to avoid devastating outcome.