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At least 1,711 records · Page 95Linked to original sources
PubMed2003

Acute occipital demyelinating lesion appearing as an infarct on diffusion magnetic resonance imaging.

PURPOSE: To report a case of a 27-year-old woman who presented with an acute right homonymous visual field deficit due to demyelination diagnosed by postprocessing analysis of the magnetic resonance imaging (MRI). DESIGN: Observational case report. METHODS: Magnetic resonance imaging analysis with an exponential diffusion-weighted imaging. RESULTS: On MRI, a left occipital lesion with mild enhancement after gadolinium infusion on the T1-weighted image, bright signal with some mass effect on the T2-weighted image, and the diffusion-weighted imaging suggested a diagnosis of an acute infarct. With the use of the exponential image technique, the T2 hyperintense signal present on the diffusion study was almost completely eliminated, changing the diagnosis and treatment plan. Subsequent examinations and MRI confirmed the diagnosis of demyelinating disease. CONCLUSIONS: In diseases such as cerebral ischemia and demyelination, MRI diffusion is often abnormal because such diseases modify the integrity of central nervous system structures. A technique that subtracts the T2 contribution to the diffusion-weighted imaging analysis supported a diagnosis of an acute demyelinating episode that was subsequently confirmed.

Acute Disease↗
PubMed2006

Diffusion-weighted magnetic resonance imaging in diagnosis of Creutzfeldt-Jakob disease.

BACKGROUND: Creutzfeldt-Jakob disease (CJD), a rare disease, is uncharacterized by computed tomography (CT) and magnetic resonance imaging (MRI). This study was aimed to evaluate the diffusion-weighted MRI (DWI) manifestations of CJD and to discuss their diagnostic value. METHODS: The findings of T(1)-weighted MRI (T(1)WI), T(2)-weighted MRI (T(2)WI), DWI and post-contrast MRI in 5 patients (3 patients with biopsy-proven CJD and 2 patients with clinically-proven CJD) were retrospectively analyzed in this study. RESULTS: Four out of the 5 patients had cerebral atrophy of various degrees. One patient showed symmetric high signal intensity at the bilateral globus pallidus and the head of the caudate nucleus, with very high signal in the cerebral cortex on the DWI. This patient only had symmetric slightly high signal at the bilateral globus pallidus and putamen on T(2)WI. One patient had high signal intensity at the basal ganglia and cerebral cortex on DWI, but abnormal T(2) signal intensity at the bilateral paraventricular white matter on MRI. Two patients presented with widely gyri-like high signal intensity at the cortex on DWI, but routine MRI showed bilateral paraventricular long T(2) signal intensity in 1 patient and no abnormal findings in another. No abnormalities were shown by both routine MRI and DWI in the last patient. CONCLUSIONS: DWI is more sensitive than its conventional counterpart in the depiction of CJD. DWI is more sensitive to detect cortical abnormal signal intensity in CJD not detected by T(2)WI.

Adult↗
PubMed2005

[Pigmented villonodular synovitis of the knee joint].

Pigmented villonodular synovitis is a rare proliferative disorder of the synovial membrane most frequently found in the knee. The etiopathology of the disease is still not understood. Present terminology differentiates between a localized (LPVNS) and a diffuse (DPVNS) form. Currently, MRI is the diagnostic imaging technique of choice. The localized form (LPVNS) can be cured definitely in almost all cases by partial arthroscopic synovectomy, whereas the treatment of the diffuse form (DPVNS) is discussed controversially concerning an arthroscopic or total synovectomy by open arthrotomy. We report a case rarely found in the literature of a patient suffering from a diffuse form of PVNS localized in the right knee joint. In this case PVNS acted as a locally aggressive and destructive lesion of immense extent invading femoral, tibial and fibular bone and the whole extending muscular system. We performed a radical synovectomy by open arthrotomy. By implanting a tumor prosthesis we prevented progression of the disease. Apart from adequate diagnosis, we recommend complete and aggressive resection of the affected tissue by performing an open arthrotomy.

Arthroplasty, Replacement, Knee↗
PubMed2001

Radiation-induced glioma presenting as diffuse leptomeningeal gliomatosis: a case report.

BACKGROUND: Leptomeningeal gliomatosis is a rare and fatal disease. METHODS: Case report. RESULTS: We report the case of a man who was presented with severe intractable headaches, lymphocytic CSF pleocytosis, and spinal leptomeningeal enhancement on contrast MRI. Meningeal biopsy demonstrated diffuse infiltration by malignant glial cells, and symptom alleviation was achieved by CSF diversion. He later developed an enhancing thalamic tumor arising within the treatment field of a remotely irradiated pituitary adenoma. Subsequent management included chemotherapy and further radiotherapy with transient response, before death from leptomeningeal and parenchymal tumor progression 16 months after diagnosis. CONCLUSION: We report a unique case embodying two rare conditions: radiation induced glioma and leptomeningeal gliomatosis. Our patient's course is novel in that symptomatic relief was achieved with CSF diversion and a combination of chemotherapy and focal radiation allowed prolonged survival.

Adenoma↗
PubMed2002

Diffusion tensor imaging in refractory epilepsy.

Diffusion tensor imaging is an imaging method that is sensitive to the molecular movement of water, which indicates cellular integrity and pathology. A patient with refractory epilepsy and normal conventional MRI was examined with diffusion tensor imaging. An area of abnormal diffusion in the right frontal lobe was identified and surgically resected. The patient had a good clinical outcome. Histopathological examination of the resected tissue showed gliosis. Our findings may affect the investigation of similar patients, and provide histopathological confirmation of diffusion abnormalities.

Adult↗
PubMed2004

Headache profile in patients with idiopathic hypertrophic cranial pachymeningitis.

BACKGROUND: Idiopathic hypertrophic cranial pachymeningitis (IHCP) is an uncommon disorder due to localized or diffuse thickening of the dura mater. While headache is the most common manifestation, the clinical characteristics of the headache in IHCP have not been well characterized. METHODS: From 1996 to 2002, 6 consecutive patients with IHCP presenting with headache were reviewed (3 women, 3 men; mean age: 49 years). Diagnosis was based on characteristic neuroimaging findings and the exclusion of secondary causes of cranial pachymeningitis. This study reported the headache characteristics, neuroimaging features, and longitudinal follow-up. RESULTS: Chronic daily headache, especially chronic migraine, was the most common headache pattern observed (4/6 patients). Lateralization of headache location appeared to correlate with the distribution of the hypertrophied dural lesions. Diagnostic delay was due to failure to evaluate with gadolinium-enhanced MRI. After treatment, headache (5/6, 83%) and neurologic deficits (2/3, 67%) improved in most patients; however, follow-up MRIs (n = 5) showed deterioration in 3 patients. CONCLUSION: The headache of IHCP is typically a chronic daily headache, often resembling chronic migraine. Correspondingly, IHCP should be considered in the differential diagnosis of refractory chronic daily headache, with or without associated cranial neuropathy or other associated neurologic deficits. The typical imaging finding on gadolinium-enhanced MRI is localized or diffuse pachymeningitis and failure to order a gadolinium-enhanced MRI is the primary reason for delayed diagnosis. Despite symptomatic improvement on longitudinal follow-up, the MRI abnormalities may not improve in parallel with the clinical symptoms.

Adult↗
PubMed2004

[Transient abnormalities associated with status epilepticus on diffusion-weighted MR imaging].

We report on two patients with transient abnormalities on MRI during status epilepticus(SE). Diffusion-weighted MR imaging(DWI) and T2-weighted and fluid-attenuated inversion recovery (FLAIR) MR images showed cortical and thalamic hyperintensity with swelling of the cortex. The lesions did not respect vascular territories. We also observed an increased signal in the ipsilateral middle cerebral artery on magnetic resonance angiography(MRA), and leptomeningeal enhancement on postcontrast MRI. Follow-up imaging revealed that the abnormal findings resolved within a few weeks, although a residual area of increased T2 signal intensity persisted. These findings suggest the presence of reversible cytotoxic and vasogenic edema induced by seizure. We conclude that this disorder should be taken into consideration in the differential diagnosis of other conditions, including ischemic stroke.

Aged↗
PubMed2003

[Importance of echocardiography and MRI in periventricular leukomalacia].

Periventricular leukomalacia (PVL) consists of focal coagulation necrosis and of more diffuse and mild white matter involvement as gliosis and lesions of immature oligodendrocytes. PVL affects essentially the premature newborn and has become the dominant form of perinatal neurological insults. Its diagnosis remains difficult to assess as neurological examination is poorly contributive. Diagnostic imaging plays an important role as it completes clinical, biological and electrophysiological data in depicting the cerebral lesions. Cerebral ultrasound remains the first imaging modality to perform in order to investigate and follow ill neonates. However ultrasound has a low sensitivity and specificity in depicting non cavitated PVL. Magnetic resonance imaging (MRI), in the acute stage, provides additional information about the extension and the depiction of hemorrhagic component of the lesions. Furthermore, diffusion-weighted MRI appears useful for the early identification of the diffuse component of PVL. MRI in the chronic stage is the only imaging method to study the progress of myelination and precise the extension of sequellar lesions.

Echocardiography↗
PubMed2005

Acute transverse myelitis in a 7-month-old boy after diphtheria-tetanus-pertussis immunization.

STUDY DESIGN: Case report of a 7-month-old boy, who developed acute transverse myelitis after diphtheria-tetanus-pertussis immunization. OBJECTIVES: To describe the clinical course of acute transverse myelitis in an infant and to review the literature regarding the association of acute transverse myelitis and vaccinations. SETTING: Department of Pediatrics, University of Kentucky, Lexington, Kentucky, USA. METHODS: Case report. RESULTS: Magnetic resonance imaging (MRI) on admission demonstrated diffuse spinal cord edema with increased signal on T-2 weighted images and faint enhancement with gadolinium infusion. Urologic symptoms improved with steroids but motor function was never fully regained. Repeat MRI of the spinal cord several months later showed diminution of cord diameter with resolution of edema and signal abnormality. CONCLUSION: Based on the clinical course and MRI findings, the daignosis of acute transverse myelitis was made. The association of previously received DPT immunization and the genesis of transverse myelitis is explored.

Diphtheria-Tetanus-Pertussis Vaccine↗
PubMed2006

Magnetic resonance-guided biopsy of suspicious breast lesions with a handheld vacuum biopsy device.

PURPOSE: To evaluate a handheld vacuum-assisted device system for magnetic resonance image (MRI)-guided breast lesion biopsy. MATERIAL AND METHODS: In 32 patients, a total of 42 suspicious breast lesions (mean diameter 7.5 mm for mass lesions, 11.6 mm for non-masslike diffuse lesions) seen with MRI (no suspicious changes in breast ultrasound or mammography) were biopsied (27 lateral, 15 medial) using a 10G vacuum-assisted breast biopsy device under MR guidance. Histology of biopsy specimens was compared with final histology after surgery or follow-up in benign lesions. RESULTS: In all biopsies, technical success was achieved. Histology revealed 11 lesions with ductal carcinoma in situ (DCIS) or invasive cancer, three with intermediate lesions (LCIS) and 28 with benign breast lesions (adenosis, infected hematoma). In one patient with discordant results of MRI and histology, surgical excision revealed medullary cancer. In the follow-up (mean 18 months) of the histological benign lesions, no breast cancer development was observed. Besides minor complications (hematoma, n = 6), with no further therapeutic interventions, no complications occurred. CONCLUSION: MRI-guided breast lesion biopsy using a handheld vacuum-assisted device is a safe and effective method for the work-up of suspicious lesions seen with breast MRI without changes in mammography or ultrasound. In the case of discordant histology of vacuum biopsy and breast MRI appearance, surgical excision is recommended.

Adult↗
PubMed2003

A pilot randomized trial of induced blood pressure elevation: effects on function and focal perfusion in acute and subacute stroke.

BACKGROUND: Small, unrandomized studies have indicated that pharmacologically induced blood pressure elevation may improve function in ischemic stroke, presumably by improving blood flow to ischemic, but noninfarcted tissue (which may be indicated by diffusion-perfusion mismatch on MRI). We conducted a pilot, randomized trial to evaluate effects of pharmacologically induced blood pressure elevation on function and perfusion in acute stroke. METHODS: Consecutive series of patients with large diffusion-perfusion mismatch were randomly assigned to induced blood pressure elevation ('treated' patients, n = 9) or conventional management ('untreated' patients, n = 6). RESULTS: There were no significant differences between groups at baseline. NIH Stroke Scale (NIHSS) scores were lower (better) in treated versus untreated patients at day 3 (mean 5.6 vs. 12.3; p = 0.01) and week 6-8 (mean 2.8 vs. 9.7; p < 0.04). Treated (but not untreated) patients showed significant improvement from day 1 to day 3 in NIHSS score (from mean 10.2 to 5.6; p < 0.002), cognitive score (from mean 58.7 to 27.9% errors; p < 0.002), and volume of hypoperfused tissue (mean 132 to 58 ml; p < 0.02). High Pearson correlations between the mean arterial pressure (MAP) and accuracy on daily cognitive tests indicated that functional changes were due to changes in MAP. CONCLUSION: Results warrant a full-scale, double-blind clinical trial to evaluate the efficacy and risk of induced blood pressure elevation in selective patients with acute/subacute stroke.

Adult↗
PubMed2005

Intravascular malignant lymphomatosis: diffusion-weighted magnetic resonance imaging characteristics.

Intravascular malignant lymphomatosis is an unusual condition in which malignant lymphoma cells form microscopic masses within the blood vessels of the central nervous system. Occlusion of the involved blood vessels can lead to multifocal cerebral infarcts. Diffusion-weighted magnetic resonance imaging (MRI) reveals a subacute infarction pattern (bright high signal intensity on b = 1000 s/mm2 images and intermediate apparent diffusion coefficient values) in the cerebral deep white matter. We present MRI findings of a 68-year-old woman with intravascular malignant lymphomatosis involving the cerebral white matter and the thoracic cord.

Aged↗
PubMed2001

Brainstem gliomas in adults: prognostic factors and classification.

In contrast to childhood brainstem gliomas, adult brainstem gliomas are rare and poorly understood. The charts of 48 adults suffering from brainstem glioma were reviewed in order to determine prognostic factors, evaluate the effect of treatment and propose a classification of these tumours. Mean age at onset was 34 years (range 16-70 years). The main presenting symptoms were gait disturbance (61%), headache (44%), weakness of the limbs (42%) and diplopia (40%). Four patterns were identified on MRI, representing non-enhancing, diffusely infiltrative tumours (50%), contrast-enhancing localized masses (31%), isolated tectal tumours (8%) and other patterns (11%). Treatment consisted of partial resection (8%), radiotherapy (94%) and chemotherapy (56%). Overall median survival was 5.4 years. On univariate analysis, the following favourable prognostic factors were identified (P< 0.01): age of onset <40 years, duration of symptoms before diagnosis >3 months, Karnofski performance status >70, low-grade histology, absence of contrast enhancement and 'necrosis' on MRI. On multivariate analysis, the duration of symptoms, the appearance of 'necrosis' on MRI and the histological grade of the tumour remained significant and independent prognostic factors (P< 0.05). Eighty-five percent of the tumours could be classified into one of the following three groups on the basis of clinical, radiological and histological features. (i) Diffuse intrinsic low-grade gliomas (46%) usually occurred in young adults with a long clinical history before diagnosis and a diffusely enlarged brainstem on MRI that did not show contrast enhancement. These patients were improved by radiotherapy in 62% of cases and had a long survival time (median 7.3 years). Anaplastic transformation (appearance of contrast enhancement, 27%) and relentless growth without other changes (23%) were the main causes of death. (ii) Malignant gliomas (31%) occurred in elderly patients with a short clinical history. Contrast enhancement and necrosis were the rule on MRI. These tumours were highly resistant to treatment and the patients had a median survival time of 11.2 months. (iii) Focal tectal gliomas (8%) occurred in young patients and were often revealed by isolated hydrocephalus. The course was indolent and the projected median survival period exceeded 10 years. In conclusion, adult brainstem gliomas are different from the childhood forms and resemble supratentorial gliomas in adults. Low-grade tumours have a clinicoradiological pattern that is so characteristic that the need for a potentially harmful biopsy is debatable. The optimum timing of treatment for supratentorial low-grade tumours remains unclear. In high-grade gliomas, the prognosis remains extremely poor despite aggressive treatment with radiotherapy and chemotherapy.

Adult↗
PubMed2001

Early diagnosis of hemorrhagic transformation: diffusion/perfusion-weighted MRI versus CT scan.

UNLABELLED: Standard magnetic resonance imaging (MRI) techniques failed to image adequately acute hemorrhagic transformation (HT). Therefore, computed tomography (CT) is still needed to exclude intracerebral hemorrhage. New MRI techniques such as diffusion- and perfusion-weighted imaging (DWI and PWI) may improve the early detection of HT. The utility of this approach requires a direct comparison of the sensitivity of CT with these MRI techniques. METHODS: Nine patients experienced an acute carotid artery territory ischemic stroke diagnosed on a first CT performed 3.8 +/- 2 h after the onset of stroke. They underwent a second CT 12 +/- 4 h after the onset of stroke, followed 35 +/- 10 min later by an MRI protocol including: (1) an axial isotropic DWI SE echo-planar imaging (EPI) sequence; (2) time of flight MR angiography (TOF MRA); (3) PWI with an axial T(2)*-weighted gradient echo EPI sequence using 20 ml gadolinium contrast agent (Gd-DTPA); HT was characterized on DWI SE EPI as a heterogeneous area of signal loss within the ischemic area; (4) at day 7, CT was also performed in all patients who had an early suspicion of bleeding according to MRI. RESULTS: An HT was detected exclusively with CT in 1 out of 9 patients, while an MRI pattern of HT was found in 6 out of 9 patients. In 5 of these 6 patients, the CT scan did not show an obvious pattern of HT. Day 7 CT confirmed HT in all patients who had early suspicion of bleeding according to DWI criteria. CONCLUSION: This study suggests that new MRI techniques may allow an early detection of HT, thus improving the management of stroke.

Adult↗
PubMed2000

High-resolution diffusion imaging using phase-corrected segmented echo-planar imaging.

Diffusion magnetic resonance imaging (MRI) was performed with a high-resolution segmented echo-planar imaging technique, which provided images with substantially less susceptibility artifacts than images obtained with single-shot echo-planar imaging (EPI). Diffusion imaging performed with any multishot pulse sequence is inherently sensitive to motion artifacts and in order to reduce motion artifacts, the presented method utilizes navigator echo phase corrections, performed after a one-dimensional Fourier transform along the frequency-encoding direction. Navigator echo phases were fitted to a straight line prior to phase correction to avoid errors from internal motion. In vivo imaging was performed using electro cardiographic (ECG) triggering. Apparent diffusion coefficient (ADC) maps were calculated on a pixel-by-pixel basis using up to seven diffusion sensitivities, ranging from b = 0 to 1129 x 10(6) s/m(2).

Adult↗
PubMed2005

Optic radiation changes after optic neuritis detected by tractography-based group mapping.

Postmortem data suggest that trans-synaptic degeneration occurs in the lateral geniculate nucleus after optic nerve injury. This study investigated in vivo the optic radiations in patients affected by optic neuritis using fast marching tractography (FMT), a diffusion magnetic resonance imaging (MRI) fiber tracking method, and group mapping techniques, which allow statistical comparisons between subjects. Seven patients, 1 year after isolated unilateral optic neuritis, and ten age and gender-matched controls underwent whole-brain diffusion tensor MR imaging. The FMT algorithm was used to generate voxel-scale connectivity (VSC) maps in the optic radiations in each subject in native space. Group maps of the left and right optic radiations were created in the patient and control group in a standardized reference frame using statistical parametric mapping (SPM99). The reconstructed optic radiations in the patient group were localized more laterally in the posterior part of the tracts and more inferiorly than in the control group. Patients showed reduced VSC values in both tracts compared with controls. These findings suggest that the group mapping techniques might be used to assess changes in the optic radiations in patients after an episode of optic neuritis. The changes we have observed may be secondary to the optic nerve damage.

Adult↗
PubMed1997

MR diffusion imaging of human intracranial tumours.

We used MRI for in vivo measurement of brain water self-diffusion in patients with intracranial tumours. The study included 28 patients (12 with high-grade and 3 with low-grade gliomas, 7 with metastases, 5 with meningiomas and 1 with a cerebral abscess). Apparent diffusion coefficients (ADC) were calculated in a single axial slice through the tumours, the sequence was sensitive to diffusion along the cephalocaudal axis. Our main finding was that ADC in contrast-enhancing areas within cerebral metastases was statistically significantly higher than ADC in contrast-enhancing areas in high-grade gliomas (P < or = 0.05). Furthermore, the ADC in oedema surrounding metastases were statistically significantly higher the ADC in oedema around high-grade gliomas (P < or = 0.02). The ADC in patients with meningiomas did not differ significantly from those seen with high-grade gliomas or cerebral metastases. The highest ADC were found within cystic or necrotic tumour areas. In one patient with a cerebral abscess, suspected of having a high-grade glioma, the ADC was similar to that in high-grade gliomas. The finding of higher ADC in cerebral metastases than in high-grade gliomas may be helpful in trying to distinguish between these tumours preoperatively; it suggests increased free extracellular and/or intracellular water fraction in cerebral metastases. The method seems to hold potential for further noninvasive characterisation of intracranial tumours.

Adult↗