Mauricio Castillo - Academia.edu (original) (raw)

Papers by Mauricio Castillo

Seminars in Ultrasound Ct and Mri, 2000

Conventional magnetic resonance (MR) imaging is able to show pathology early on and to provide th... more Conventional magnetic resonance (MR) imaging is able to show pathology early on and to provide the radiologist with some degree of lesion characterization based on the relaxation time of different tissues. Many times, however, conventional MR imaging is not capable of depicting abnormalities at a time when early therapy may be successful, or of differentiating among different types of lesions before surgery. Diffusion-weighted imaging (DWI), a technique that is relatively new, is rapidly gaining popularity. Its increased use stems from the fact that many of the newer MR units are echo-planar capable. Although DWI may be obtained without echo-planar techniques, most DWI is now obtained by using gradients capable of very fast rising times. Echo-planar DWI may be obtained in a matter of seconds and, thus, is much less sensitive to bulk motion than other imaging techniques. Although DWI has been used extensively for the evaluation of acute cerebral infarctions, new uses for it are being explored constantly. In this article we address the nature of DWI and its use in the stroke patient as well as in other clinical situations where we believe it is useful.

Journal of Computed Tomography, 1985

Three cases of intracranial perineural metastasis from adenoid cystic carcinoma of the head and n... more Three cases of intracranial perineural metastasis from adenoid cystic carcinoma of the head and neck are presented. The metastases presented more than 1 year (14 months to 5.5 years) after the primary tumor had been successfully treated without any evidence of local recurrence. Computed tomography of the intracranial metastasis demonstrated well-demarcated, hyperdense, enhancing extraaxial masses indistinguishable from meningioma. An intracranial extraaxial mass lesion with the appearance of a meningioma in a patient with known adenoid cystic carcinoma of the head and neck, regardless of the presence or absence of local recurrence, should be considered as metastasis until proved otherwise.

BACKGROUND AND PURPOSE: Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC)... more BACKGROUND AND PURPOSE: Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps provide information at MR imaging that may reflect cell attenuation and integrity. We hypothesized that cerebellar tumors in children can be differentiated by their ADC values.

Distinguishing between toxoplasmosis and lymphoma brain lesions in AIDS patients is difficult but... more Distinguishing between toxoplasmosis and lymphoma brain lesions in AIDS patients is difficult but clinically relevant. This study was performed to test the hypothesis that diffusion-weighted (DW) imaging with apparent diffusion coefficient (ADC) maps can be used to distinguish these two lesions.

Diffusion-weighted MR imaging of the spine has been used to differentiate benign from pathologic ... more Diffusion-weighted MR imaging of the spine has been used to differentiate benign from pathologic vertebral body compression fractures. We sought to determine the utility of diffusion-weighted MR imaging in the detection of vertebral metastases and to compare it with conventional noncontrast T1- and T2-weighted MR imaging. Fifteen patients with metastases to the spine were studied using conventional MR imaging and diffusion-weighted imaging. Blinded review of all images was undertaken, and patients were categorized according to whether they had focal or multiple lesions. The signal intensity of the lesions was compared on T1-, T2- (fast spin-echo), and diffusion-weighted images. In five patients with focal disease, metastases were hypointense on T1-weighted images; hypointense (n = 2), isointense (n = 1), or hyperintense (n = 2) on T2-weighted images; and hypointense (n = 3) or hyperintense (n = 2) on diffusion-weighted images with respect to presumed normal bone marrow. In 10 patients with disease in multiple sites, all lesions were hypointense on T1-weighted images; hypointense (n = 2), isointense (n = 4), hyperintense (n = 2), or mixed (n = 2) on T2-weighted images; and hypointense (n = 5), hyperintense (n = 3), or mixed (n = 2) on diffusion-weighted images with respect to presumed normal bone marrow. As used in this study, diffusion-weighted MR imaging of the spine showed no advantage in the detection and characterization of vertebral metastases as compared with noncontrast T1-weighted imaging, but was considered superior to T2-weighted imaging.

BACKGROUND AND PURPOSE: Radiologic evaluation of CSF leaks is a diagnostic challenge that often i... more BACKGROUND AND PURPOSE: Radiologic evaluation of CSF leaks is a diagnostic challenge that often involves multiple imaging studies with the associated expense and patient discomfort. We evaluated the use of screening noncontrast high-resolution CT in identifying the presence and site of CSF rhinorrhea and otorrhea and compared it with contrast-enhanced CT cisternography and radionuclide cisternography.

Marchiafava-Bignami is a rare toxic disease seen mostly in chronic alcoholics that results in pro... more Marchiafava-Bignami is a rare toxic disease seen mostly in chronic alcoholics that results in progressive demyelination and necrosis of the corpus callosum. The process may extend laterally into the neighboring white matter and occasionally as far as the subcortical regions. We present the MR imaging findings in two patients who presented acutely and review the features of the disease and of other acute alcohol-related disorders.

BACKGROUND AND PURPOSE: Bipolar affective disorder (BPAD) can have its onset during childhood, bu... more BACKGROUND AND PURPOSE: Bipolar affective disorder (BPAD) can have its onset during childhood, but the diagnosis may be difficult to establish on the basis of clinical findings alone. Our purpose was to determine whether proton MR spectroscopy can be used to identify abnormalities in the brain of children with BPAD.

Seminars in Ultrasound Ct and Mri, 2000

Journal of Computed Tomography, 1985