Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Several studies have demonstrated that brain atrophy can be detected over relatively short intervals from the earliest stages of multiple sclerosis (MS). Reviewing the published data, the authors highlight some hypothetical pathological mechanisms proposed as determinants of brain atrophy. ⋯ Examination of the pathological mechanisms proposed in the reviewed studies led the authors to believe that inflammation is only in part responsible for the development of brain atrophy. This conclusion may have an implication for the strategies of tissue protection advocated in the early stages of the RR course and strengthen recent evidence indicating that anti-inflammatory immunomodulatory agents and immunosuppressive treatments, which predominantly act against the inflammatory component of disease activity, may not have similar effects on progressive tissue loss, either in RR or progressive MS.
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Headaches are a universal experience and one of the most common causes for physician consultation. The physician must determine whether a neuroimaging study is warranted to aid in the diagnosis of primary or secondary headaches. ⋯ Neuroimaging has been crucial in the investigation of the pathogenesis of migraine and cluster headaches. Secondary headaches, which may be diagnosed by neuroimaging studies, include subarachnoid hemorrhage, cerebral venous thrombosis, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, aqueductal stenosis, and arterial dissection.
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The authors describe 2 cases of posterior fosa venous infarction. A 56-year-old woman with essential thrombocytemia presented with fluctuating complaints of headache, nausea, vomiting, left-sided numbness-weakness, and dizziness and became progressively stuporous. Cranial magnetic resonance imaging (MRI) showed bilateral parasagittal fronto-parietal and left cerebellar contrast-enhancing hemorrhagic lesions. ⋯ Digital subtraction angiography showed right transverse and sigmoid sinus occlusion. The authors suggest that one should investigate the possibility of venous infarction in the presence of posterior fossa lesions that are often hemorrhagic and are not within any arterial territory distribution but respect a known venous drainage pattern. Recognition of the observed clinical and neuroimaging features can lead to earlier diagnosis and, potentially, more effective management.
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Review Case Reports
Ganglioneurocytoma mimicking a malignant tumor: case report with a literature review of the MRI appearance of neurocytomas and gangliogliomas.
A 14-year-old girl presented with symptoms of increased intracranial pressure after her head was squeezed at a party. MRI demonstrated a mass that was hypointense to brain on T1WI and heterogeneous in signal on PD and T2WI; compression of the ventricle, midline shift, and mild ventriculomegaly also were present. Contrast enhancement was extensive and heterogeneous, mimicking a malignant tumor. Neuropathology revealed a ganglioneurocytoma.
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Over the past decade, a number of new kinetic modeling techniques have been developed for PET and SPECT ligands. This article will review commonly used modeling solutions for reversible positron-emission tomography (PET) and single photon emission computed tomography (SPECT) radioligands, with an emphasis on noninvasive methods. ⋯ These parameters will be defined, and their relationship to analogous parameters in pharmacology will be discussed. Then the major approaches are presented under the categories of graphical or mathematical as well as invasive or noninvasive.