Biomedical subjects
Publications and source records attributed to Mauricio Castillo.
CT and MRI of the brain were performed in an acutely ill child with serology-proven eastern equine encephalitis. The studies showed lesions involving the basal ganglia and thalami according with findings described in the literature. In the correct clinical setting, these findings should prompt the obtaining of appropriate serologic confirmatory tests and lead to institution of control measures to prevent spread of the disease.
This article discusses the upper cranial nerves (I, III-VIII) and their anatomy as it pertains to intra-axial nuclei and tracts, cisternal portions, and extracranial portions. In addition, the most common pathologic processes affecting the upper cranial nerves are discussed and illustrated. Because the evaluation of small structures requires imaging techniques that provide high resolution and contrast, MR imaging is the examination of choice. CT still plays a limited but important role in the evaluation of intraosseous portions of some cranial nerves.
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Explore the source record for details and available documents.
Five to 25% of patients with systemic sarcoidosis also have CNS involvement. Patients with systemic disease may initially present with neurologic symptoms, and rarely, the sarcoidosis may be isolated to the CNS. A typical imaging feature is thickening and enhancement of the basilar leptomeninges of the brain. Other imaging findings, such as enhancing or nonenhancing parenchymal lesions, dural, and bone lesions may occur in the head and spine. Because there is a high rate of progression and recurrence following treatment, imaging follow-up is recommended in all patients.
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Explore the source record for details and available documents.
Proton magnetic resonance spectroscopy (MRS) and neuropsychological testing were conducted on 8 children with attention-deficit/hyperactivity disorder (ADHD-H), with no learning disabilities or comorbidities and 8 controls. Magnetic resonance spectroscopy revealed increased Glutamate/Glutamine in both frontal areas, and increased N-acetyl aspartate and Choline in the right frontal area of the ADHD-H subjects. Neuropsychological testing revealed few within- and between-group differences. Findings related to frontal lobe dysfunction in ADHD-H subjects were noted. N-acetylasparte/creatine (NAA/Creatine) in the right frontal region, and myoinositol/creatine (Myo inositol/Creatine) in the right and left frontal regions appear to be highly associated with the regulation of sensorimotor, language, and memory and learning functioning in children with ADHD-H.
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BACKGROUND AND PURPOSE: The GliaSite system delivers local, high radiation after brain tumor resection. We describe the imaging appearance of the device and the changes it causes. METHODS: Eight patients with brain tumors were treated with this system. After surgery, all underwent MR imaging, and one underwent CT. Five were examined 1 month after radioactive unloading and every 2 months thereafter (total, 6-9 months). Initial studies were assessed for balloon appearance and complications; subsequent studies, for signal intensity and enhancement. Three patients underwent multivoxel proton MR spectroscopy, and one underwent MR perfusion study. Spectra were reviewed for metabolites suggesting tumor; perfusion studies were reviewed for increased relative cerebral blood volume and flow. RESULTS: CT showed the hyperattenuating balloon with considerable artifact. All MR images showed the device and adjacent brain. Follow-up studies showed enhancement and T2 hyperintensity in five patients. In one, enhancement progressively disappeared with no evidence of tumor recurrence. Another patient had progressive enhancement and low relative cerebral blood volume and flow; biopsy showed necrosis and inflammation. One patient had progressive enhancement and high choline levels (proved anaplastic astrocytoma). In another, T2 signal intensity and contrast enhancement progressed owing to tumor and bacterial infection. The last patient had a high choline level (proved radionecrosis); enhancement progressed over 5 months. In three, the device was removed early because of bleeding, mass effect, and therapeutic changes (no follow-up). CONCLUSION: Good balloon visualization was possible with MR imaging. After brachytherapy, all patients developed T2 hyperintensity; stable or progressive enhancement occurred with tumor recurrence and radionecrosis. High choline levels were suggestive of, but not necessarily diagnostic of, tumor.
Giant cell angiofibroma (GCA) is a benign pathologic entity that has recently been reported in the literature. Originally described in the orbit, extraorbital sites of disease have also been reported. Herein, we describe the clinical, imaging, and pathologic findings of a case of GCA of the orbit.
BACKGROUND AND PURPOSE: Surgically or conservatively treated brain abscesses may resolve, or pus may re-accumulate, requiring further intervention or treatment change. We hypothesized that diffusion-weighted (DW) imaging is useful in depicting features of abscesses related to therapeutic success or failure. METHODS: Conventional contrast-enhanced T1- and T2-weighted imaging and DW imaging were performed in seven patients (aged 30-69 years) with proved pyogenic brain abscesses. The center of the abscess was qualitatively and quantitatively analyzed at initial and follow-up imaging in all patients. We correlated the signal intensity on trace DW images and the apparent diffusion coefficients (ADCs) with the clinical and laboratory data, particularly with respect to treatment failure and repeat therapy. RESULTS: Surgical drainage was performed in six patients; one patient was treated with only antibiotics. All abscess cavities initially had high signal intensity (restricted diffusion) on DW images, with a mean ADC value of 0.52 x 10 (-3)mm (2)/s. Low signal intensity at DW imaging with high ADC were seen on follow-up images in the patient receiving medication and in four patients in whom the abscesses were drained; this correlated with a good therapeutic response. Two patients underwent drainage; their second follow-up DW images showed areas of high signal intensity and low ADC values suggesting re-accumulation of pus. Increased C-reactive protein level and WBC count correlated well with DW image findings. CONCLUSION: DW imaging was superior to conventional MR imaging in evaluating the success or failure of abscess therapy. Restricted diffusion in a drained abscess corresponded to pus.
Developmental venous anomalies (DVAs) are common variants of cerebral venous drainage that are typically incidental findings on contrast-enhanced MR imaging studies. We present four cases of asymptomatic DVAs that demonstrate increased cerebral blood flow, cerebral blood volume, mean transit time, and time to peak on perfusion MR images. Our study indicates that alterations in perfusion MR imaging parameters can be seen with uncomplicated DVAs and do not necessarily imply a more ominous underlying etiologic factor, such as hypervascular tumor or stroke.
MR spectroscopy is a non-invasive technique for measuring tissue metabolites. Changes in tissue metabolites may be useful for diagnosing or characterizing primary and other brain neoplasms, planning treatment, and assessing the results of treatment. Ongoing improvements in equipment and pulse sequence design may make full brain spectroscopy clinically practical in the near future. The authors review the basic concepts of MR spectroscopy and its use in clinical management of brain neoplasms.
In this article, the authors present a brief history of MR angiography (MRA) of the neck with emphasis on the techniques developed, particularly recent ones, to improve image quality. The goal of MRA is to eventually replace catheter angiography. The use of MRA, particularly contrast enhanced MRA with regards to pathology (atherosclerotic disease/plaque formation, dissection and post-traumatic aneurysm) involving the extra-cranial carotid and vertebral arteries is addressed. The authors also comment on computed tomographic angiography and sonography and how they compare with contrast enhanced MRA when pertinent.