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PubMed2006

[Spontaneous intracranial hypotension due to a broken dorsal perineural cyst].

INTRODUCTION: It is now recognized that most, if not all, cases of spontaneous intracraneal hypotension result from spontaneous cerebrospinal fluid (CSF) leaks. The exact cause of spontaneous leak often remains unclear. However, two factors are typically considered: trivial trauma and weakness of the dural sac. CLINICAL CASE: A 61-year-old woman came with a one week history of orthostatic headache. The neurologic examination and funduscopy were normal. Brain contrast- enhanced magnetic resonance imaging (MRI) showed subdural fluid collections and diffuse pachymeningeal enhancement. Cervical-dorsal-lumbar MRI showed a dilated spinal venous plexus throughout the canal. Computed tomography (CT) myelography demonstrated perineural cysts at the level of D7, D8, D9 and D10. The right D10 cysts was broken with extravasation of contrast medium into the extradural space. Three months later, after rest and hydration, the patient was asymptomatic. The brain and dorsal MRI, four months later were normal. CONCLUSIONS: Spontaneous CSF leaks from broken perineural cysts has been exceptionally demonstrated. CT myelography should be employed to detect the involved site.

Brain↗
PubMed2006

In vivo quantification of spinal and bulbar motor neuron degeneration in the G93A-SOD1 transgenic mouse model of ALS by T2 relaxation time and apparent diffusion coefficient.

Magnetic resonance imaging (MRI) has provided important information in characterizing amyotrophic lateral sclerosis (ALS) in humans and in animal models. A frequently used animal model to study mechanisms of pathogenesis and the efficacy of drugs in ALS is a transgenic mouse over-expressing the human mutated G93A-superoxide dismutase 1 (G93A-SOD1). In our study, we applied MRI to find suitable progression markers, which can be used to monitor the development of ALS and to evaluate therapeutic approaches at early stages of the disease. Therefore, we generated parameter maps of the spin-spin relaxation time (T2) and the apparent diffusion coefficient (ADC) starting at day 70 after birth, i.e., before motor scores decline around day 90. Depending on the progression of the disease, G93A-SOD1 mice showed significantly increased values of T2 in the brain stem motor nuclei Nc. V (trigeminal nucleus), VII (facial nucleus), and XII (hypoglossal nucleus), and spinal cord compared to non-transgenic wild-type mice and transgenic mice over-expressing the non-mutated wild-type human SOD1 (tg-SOD1). Similar effects in these motor nuclei were revealed by ADC mapping. Furthermore, in the upper spinal cord, a dorsal-ventral difference with significantly higher T2 values in the ventral part was demonstrated by T2 mapping. While both T2 and ADC might prove useful as progression markers and enable the longitudinal non-invasive evaluation of ALS in G93A-SOD1 mice, the potential is limited by age-dependent effects in case of ADC mapping.

Amyotrophic Lateral Sclerosis↗
PubMed2002

MR imaging of diffuse adenomyosis changes after GnRH analog therapy.

PURPOSE: To evaluate uterine changes on MRI before and after GnRH analog (GnRHa) treatment in diffuse adenomyosis. MATERIALS AND METHODS: Thirty-one patients with MRI features suggestive of diffuse adenomyosis received GnRHa for 6 months. Diffuse adenomyosis was sub-classified as: symmetric (symmetric/ entire widening of the junctional zone [JZ]) and asymmetric (asymmetric/ partial widening of JZ). Pre- and post-high signal intensity (SI) foci and JZ width, and post-demarcated change (interface of adenomyosis with the myometrium became more discrete with a concomitant decrease in JZ width) were analyzed. RESULTS: Before therapy, 15 of 18 asymmetric contained high SI foci compared to none of symmetric. After therapy, JZ width decreased (P < 0.0001). Eight asymmetric and none of symmetric showed demarcated change with resolved high SI foci. CONCLUSION: Our results suggest the use of GnRHa is associated with a decrease of JZ width in adenomyosis. Asymmetric adenomyosis with high SI foci appears to be the most sensitive to hormonal therapy.

Adult↗
PubMed2005

Transient splenial lesion of corpus callosum associated with antiepileptic drug: conventional and diffusion-weighted magnetic resonance images.

Transient focal lesions of splenium of corpus callosum can be seen as a component of many central nervous system diseases, including antiepileptic drug toxicity. The conventional magnetic resonance (MR) findings of the disease are characteristic and include ovoid lesions with high signal intensity at T2-weighted MRI. Limited information exists about the diffusion-weighted MRI characteristics of these lesions vanishing completely after a period of time. We examined the conventional, FLAIR, and diffusion-weighted MR images of a patient complaining of depressive mood and anxiety disorder after 1 year receiving antiepileptic medication.

Adolescent↗
PubMed1999

[Prognostic aspects of scintigraphy and MRI during the first 6 months of reflex sympathetic dystrophy of the distal lower limb: a preliminary prospective study of 4 cases].

PURPOSE: The appearance of scintigraphic and magnetic resonance imaging during the evolution of reflex sympathetic dystrophy of the foot is not well known and subject to controversies. The purpose of this preliminary study is to compare these two types of investigation during the first 6 months of evolution. METHODS: 4 non-selected patients with a diagnosis of acute reflex sympathetic dystrophy of the foot (no more than 2 months of evolution and more than 3 out of 6 clinical criteria suggesting a "warm" phase) were studied prospectively. A clinical evaluation, scintigraphy and magnetic resonance imaging (MRI) were performed at diagnosis and after 3 and 6 months. All available examinations (n = 22) were analyzed independently by independent observers. RESULTS: Clinically 3 of 4 patients developed or previously had another site of sympathetic dystrophy confirmed by total body scintigraphy. After 6 months 2 of 4 patients still have a "warm" dystrophy. Bone scanning showed localized or diffuse tracer uptake and MRI showed bone and soft tissue edema when the sympathetic dystrophy was and/or remained clinically "warm". MRI bone edema moved from one location to another in 3 of 4 patients during the follow-up. There was a good correlation between bone scan and MRI images. In "warm" dystrophy, MRI was positive 5 out of 7 times and scintigraphy in all cases. Bone edema and tracer uptake faded simultaneously although the latter was more diffuse and more persistent than the former. CONCLUSION: MRI as well as bone scintigraphy are suitable for the diagnosis of warm dystrophy of the foot. Both exams remain positive when the dystrophy is still "warm" after 6 months. The radiographic evolution after 6 months still has to be evaluated.

Bone Diseases↗
PubMed2006

The relationship between the extensor tendon enthesis and the nail in distal interphalangeal joint disease in psoriatic arthritis--a high-resolution MRI and histological study.

OBJECTIVES: Diffuse swelling of the distal interphalangeal (DIP) joint beyond the joint margin is a common feature of arthritis in psoriatic arthritis (PsA). The purpose of this study was to explore the microanatomical basis for the inflammation and nail disease in PsA using a combined high-resolution magnetic resonance imaging (MRI) and histological studies. METHODS: High-resolution MRIs of the DIP joint were obtained in 30 subjects [10 PsA, 10 osteoarthritis (OA) and 10 normal volunteers]. The relationship between the DIP joint capsule and associated tendon enthesis and the nail bed and root were evaluated. Histological studies to define the relationship between the normal cadaveric DIP joint capsule and the nail root were performed on the middle and ring fingers of 10 dissecting room cadavers. RESULTS: On MRI, the dorsal capsular enthesis was the epicentre of an inflammatory reaction. This extended to involve the soft tissues adjacent to the nail in 8 of 10 cases in PsA, but only 4 of 10 cases in OA where the inflammation is less intense and in none of the normal fingers. The DIP joint capsule was intimately linked with the nail complex on histology, with the dorsal, volar and lateral aspects of the nail bed being ensheathed in fibres extending from the entheses. CONCLUSION: The study suggests that the extended nature of the enthesis organ associated with the DIP joint may explain the diffuse nature of the inflammatory response around the nail in PsA. Therefore the nail is as much an integral part of the enthesis organ as it is of the skin, which has implications for a better understanding of the disease.

Adolescent↗
PubMed2001

Spontaneous intracranial hypotension with diffuse dural enhancement of the spinal canal and transient enlargement of the pituitary gland.

Spontaneous intracranial hypotension is a rare phenomenon characterized by postural headache, neck rigidity, nausea and vomiting. Imaging findings on magnetic resonance imaging (MRI) is characteristic with diffuse intracranial pachymeningeal thickening and enhancement following intravenous gadolinium. We present a case of spontaneous intracranial hypotension with two unusual imaging findings; pachymeningeal enhancement of the spinal canal and enlargement of the pituitary gland in addition to the diffuse intracranial pachymeningeal enhancement. In this case report, we will discuss the clinical features, MRI findings and underlying pathophysiology of this rare condition.

Adult↗
PubMed2006

Central nervous system aspergillosis: magnetic resonance imaging, diffusion-weighted imaging, and magnetic resonance spectroscopy features.

Aspergillus infection is invasive in nature in the immunosuppressed population and disseminates throughout the body, with the brain being a common site. Conventional magnetic resonance imaging (MRI) combined with diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy (MRS) play a life-saving role in the early diagnosis and treatment monitoring of this potentially fatal infection. We present MRI, DWI, and MRS findings of a case of central nervous system aspergillosis with treatment follow-up.

Adult↗
PubMed2006

Advanced MRI could help to differentiate meningeal carcinomatosis with mass effect from cerebral metastasis in prostate cancer.

Prostatic neoplasms are the second cause of mortality due to cancer in men. Brain metastases are a rare presentation, whereas epidural localizations are relatively frequent. However both occur late in the evolution of the cancer. Thus a reliable, fast and non-invasive diagnosis would be useful in this setting. Regarding the prognosis of such disease, earlier treatment may probably influence the quality of life and postpone fatal evolution. However improved survival is more hypothetical. We report the case of a 69-year old man with a hormone refractory adenocarcinomatous prostatic cancer presenting with diffuse intracranial metastases. An MRI analysis using T2 perfusion images, diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps excluded intra-axial brain metastases and concluded to the existence of voluminous nodular dural metastases. We discuss the imaging techniques and review literature of neurological complications of prostate cancer.

Carcinoma↗
PubMed2004

Off-resonance binomial preparatory pulse technique for high sensitivity MRI of H2O17.

H2O17 is a freely diffusible tracer and naturally occurring isotope of O16 detectable by MRI and has been shown to be useful for assessing cerebral perfusion in animal studies using direct and indirect MR detection techniques. However, earlier MR techniques are either not sensitive to changes in small concentrations of tissue H2O17 or are not practical for use on clinical scanners. In this work, a novel method for detecting H2O17 with high sensitivity has been proposed that uses a short, intense, binomial preparatory spin lock pulse with resonance offsets for high sensitive rapid, multislice imaging of tissue H2O17. Two sets of phantom experiments were performed on the 1.5 T and repeated on 3.0 T to assess the feasibility of the proposed technique. The phantom was constructed using ovalbumin and doped with 0.4 atom% and 1.0 atom% H2O17. After obtaining initial parameters, the proposed technique was validated in an anesthetized primate model that was injected with 1.8 cc of 40 atom% H2O17. Phantom experiments showed that the proposed technique was able to detect H2O17 with relatively high sensitivity and high B1 amplitude (and small offsets) preparatory pulses produced similar results as low B1 amplitude (and larger offsets). Primate brain study showed a 42.97% difference in mean signal intensity between pre- and post-H2O17 injection. The proposed technique was successfully implemented on a clinical scanner and was able to detect H2O17 with relatively high sensitivity. Primate study has shown that such a technique can be successfully used for human imaging applications to investigate and assess cerebral perfusion.

Animals↗
PubMed1994

Quantitative diffusion MR imaging of cerebral tumor and edema.

The detection of brain tumors using standard techniques of qualitative, relaxation-weighted magnetic resonance imaging (MRI) requires the application of contrast agents. We investigated whether or not it is possible to use diffusion-weighted MRI to localize tumors without contrast enhancement. Three different experimental rat brain tumors were studied: F98 glioma, RN6 Schwannoma and E376 neuroblastoma. We found a marked hypointensity in the region of the tumor and edema in heavily diffusion-weighted images, which corresponded well with the histological presentation. Quantitative maps of the apparent diffusion coefficient (ADC) allowed a better localization of the tumor than that obtained by regional presentation of T2 times, particularly under conditions in which peritumoral edema was absent. The ADC differences of the three tumor types were statistically not significant. Based upon regions-of-interest evaluations, tumor could be distinguished from peritumoral edema and normal brain tissue. However, a sharp demarcation between tumor and peritumoral edema was not possible, and this is attributed to a similar enlargement of interstitial space. It was concluded that diffusion-weighted MRI possesses a high potential for the detection of brain tumors but does not allow precise demarcation of the tumor border.

Animals↗
PubMed2002

Cognitive dysfunction in patients with mildly disabling relapsing-remitting multiple sclerosis: an exploratory study with diffusion tensor MR imaging.

Previous studies assessing the magnetic resonance imaging (MRI) correlates of cognitive dysfunction in multiple sclerosis (MS) achieved conflicting results. Diffusion tensor (DT)-MRI provides metrics that are sensitive to the macro- and microscopic MS lesion load with increased specificity to the more destructive aspects of MS pathology than conventional imaging. We performed an exploratory study to assess the magnitude of the correlation between quantities derived from DT-MRI and measures of cognitive impairment in patients with relapsing-remitting (RR) MS.T2, T1, DT-MRI scans of the brain and an extensive battery of neuropsychological tests (exploring language, complex reasoning, attention and memory) were obtained from 34 RRMS patients. We measured T2 and T1 lesion volumes (LV) and brain volume. Average lesion mean diffusivity (D) and fractional anisotropy (FA) were calculated. D and FA histograms from the brain tissue (BT), the normal-appearing brain tissue (NABT), the normal-appearing white matter (NAWM) and the normal-appearing gray matter (NAGM) were also obtained. Nine patients (26.5%) were found to be cognitively impaired. Moderate correlations were found between symbol digit modalities test, verbal fluency test and 10/36 spatial recall test scores and T2 LV, T1 LV and average lesion, WBT, NABT, NAWM and NAGM values (r values ranging from -0.30 to -0.53). No correlations were found between any of the neuropsychological test scores and brain volume, average lesion FA and WBT FA.DT-MRI provides quantitative metrics that seem to reflect the severity of language, attention and memory deficits in patients with RRMS. This study also suggests that the extent and the intrinsic nature of the macroscopic lesions as well as the damage of the NAWM and NAGM all contribute to the neuropsychological deficits of RRMS patients.

Adult↗
PubMed2004

Diffusion weighted image negative transient ischaemic attack and reversible ischaemic neurological deficit. A report of 10 patients with complete recovery.

Diffusion-weighted magnetic resonance imaging (DWI MRI)-negative transient ischaemic attack (TIA) in hyperacute stroke is a well-known clinical entity. However, no precise analysis of this phenomenon has been reported. We identified 10 patients with TIA or reversible ischaemic neurological deficits (RIND) with no focal hyperintensity on DWI MRI among 108 consecutive acute stroke patients who underwent DWI MRI. In these patients, we analysed the apparent diffusion coefficient (ADC) and determined the ipsilateral/contralateral ratio (IC ratio) to elucidate factors that may contribute to this phenomenon. Each patient also underwent simultaneous magnetic resonance angiography (MRA). The mean IC ratio in our study population was 0.976. Of the 10 patients, 7 had a proximal vascular stenosis on MRA. We discuss the pathophysiology underlying negative DWI MRI results in patients with TIA or RIND.

Adult↗
PubMed2002

Magnetic resonance imaging in basilar artery occlusion.

CONTEXT: Acute basilar artery occlusion has particularly high mortality and morbidity. OBJECTIVE: To determine the potential utility of advanced magnetic resonance imaging (MRI) methods, including diffusion-weighted imaging, for the early management of patients with basilar artery thrombosis. DESIGN: Case series. SETTING: Institute of Neuroradiology and Department of Neurology, Johann Wolfgang Goethe University, Frankfurt, Germany. PATIENTS: In 4 patients with occlusion of the basilar artery, MRI was performed, including T2-weighted and diffusion-weighted imaging (DWI) sequences and magnetic resonance angiography (MRA) in the short-term phase (<12 hours). Three patients underwent intra-arterial thrombolysis. Clinical outcome was obtained 10 days after symptom onset. RESULTS: The MRA was performed 3.5 to 11.5 hours after symptom onset and showed basilar artery occlusion in all cases. The DWI revealed different patterns of ischemic lesions. In 2 patients, no or only small lesions could be identified; the remaining showed multiple and large lesions within the posterior circulation territory. Initial clinical status was severely impaired in all cases (Rankin scale score, 4-5). Thrombolysis was initiated in 3 patients, leading to successful recanalization in 2. Clinical outcome was favorable in the 2 patients with small DWI lesions and successful reperfusion (Rankin scale score, 2), whereas it was worse in those with large DWI lesions and persisting occlusion (death, persisting coma). CONCLUSIONS: In critically ill patients with acute basilar occlusion, the extent of DWI lesion involvement can be highly variable. Small DWI lesions seem to be associated with a favorable outcome if reperfusion is achieved with thrombolysis. This could potentially be the case independent of time from symptom onset.

Aged↗
PubMed2006

Diffusional kurtosis imaging in the lung using hyperpolarized 3He.

Diseases of the small airspaces represent an increasingly important health problem. Asthma is primarily a disease of airway dysfunction, while chronic obstructive pulmonary disease (COPD) is associated with abnormalities in both the small airways and the alveoli. Conventional diffusion magnetic resonance imaging (MRI) of hyperpolarized noble gases, because of the short T(2)* of the gas, is only capable of monitoring diffusion over short times and hence only short distances. Diffusion imaging is therefore only sensitive to changes in small structures of the lung (primarily the alveoli), and will not adequately interrogate diffusion along the longitudinal axes of bronchi and bronchioles. In this communication we present a new method, termed diffusional kurtosis imaging (DKI), that is particularly sensitive to diffusion over longer distances. DKI may therefore be more sensitive to abnormalities in the bronchioles and bronchi than conventional diffusion imaging. Preliminary DKI measurements on healthy human subjects and one patient with symptoms suggestive of small airway disease are presented. Although the apparent diffusion coefficient (ADC) in the patient was similar to that in the normal controls, diffusional kurtosis was markedly reduced. This suggests that DKI measurements may be useful for assessing diseases of the small airways.

Artifacts↗
PubMed2003

The use of quantitative magnetic-resonance-based techniques to monitor the evolution of multiple sclerosis.

Conventional MRI can improve accuracy in the diagnosis of multiple sclerosis (MS) and monitor the efficacy of experimental treatments. However, conventional MRI provides only gross estimates of the extent and nature of tissue damage associated with this disease. Other quantitative magnetic-resonance-based techniques have the potential to overcome the limitations of conventional MRI and, as a consequence, to improve our understanding of the natural history of MS. Magnetisation-transfer, diffusion-weighted, and functional MRI--as well as proton magnetic-resonance spectroscopy--are helping us to elucidate the mechanisms that underlie injury, repair, and functional adaptation in patients with MS. These techniques are substantially changing our understanding of how MS causes irreversible disability and should be used more extensively in clinical trials and in studies of disease progression.

Brain Mapping↗
PubMed2001

Diffusion tensor imaging study of subcortical gray matter in cadasil.

BACKGROUND AND PURPOSE: In cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), water diffusion changes suggestive of microstructural tissue alterations have been recently reported in abnormal- and normal-appearing white matter as seen on T2-weighted images. In the subcortical gray matter, typical lacunar infarcts are repeatedly observed. Whether microstructural tissue changes are also present outside these lesions within the putamen or thalamus remains unknown. METHODS: We used diffusion tensor imaging, an MRI method highly sensitive to cerebral microstructure, in 20 CADASIL patients and 12 controls. Both the trace of the diffusion tensor [Tr(D)] and an anisotropic diffusion index (volume ratio) of diffusion were measured within the putamen and thalamus outside typical lacunar infarcts as detected on both T1- and T2-weighted images. RESULTS: A significant increase in Tr(D) and a decrease in anisotropy were observed in the putamen and thalamus in patients. The right/left indices of Tr(D) in the thalamus, but not in the putamen, were strongly correlated with the corresponding indices calculated in the white matter of the centrum semiovale. In addition, the diffusion increase in the thalamus was positively correlated with Tr(D) and with the load of small deep infarcts within the white matter and negatively correlated with the Mini-Mental State Examination score. CONCLUSIONS: Our results suggest that microstructural tissue alterations are present in the putamen and thalamus, outside the typical lacunar infarcts in CADASIL. In the thalamus, these microstructural changes appear constant and are even observed in asymptomatic subjects. Some of these thalamic changes appear to result from degeneration of thalamocortical pathways secondary to ischemic white matter damage. The importance of this degenerative phenomenon in the pathophysiology of CADASIL requires further investigation.

Analysis of Variance↗
PubMed2001

[Magnetic resonance imaging findings of postresuscitation encephalopathy: sequential change and correlation with clinical outcome].

OBJECTIVE: The purpose of this study was to describe the findings of sequential magnetic resonance imaging (MRI) in postresuscitation encephalopathy. Although its outcome is known to be overwhelming, but its acute findings by variable imaging methods are subtle and show only limited values. The correlation of the findings of MRI with clinical outcome were also analyzed. METHODS: Twelve patients with global cerebral anoxia who underwent MRI with conventional and diffusion-weighted imaging were enrolled in this study. Compared with normal MRI images, abnormal signal regions were checked and described in cortex, basal ganglia and white matter. Also medical records were carefully reviewed to study the cause, the time necessary for resuscitation and long term clinical outcome. RESULTS: The earliest finding was obtained by diffusion-weighted image less than 24 hours (acute period) in bilateral cerebral cortex as bright high signal intensity regions. Similar abnormality of bright high signal area in FLAIR and T 2 was followed according to the time elapsed in early subacute period (1-13 days). Succeedingly, white matter was involved and laminar necrosis in cortical area was observed in late subacute period (14-20 days). Finally, diffuse brain atrophy and obtundation of gray-white matter junction were seen in chronic stage (after 21 days). These MR findings were coincided well with histopathological findings reported in literatures. The poor outcome was closely and significantly correlated with abnormality in MR images. CONCLUSION: MRI was a useful diagnostic modality to diagnose the whole brain ischemic encephalopathy and to predict the prognosis.

Adult↗