Vertebral hemangioendothelial sarcoma: MR findings.
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Adult↗
Biomedical subjects
M Castillo
Publications and source records attributed to M Castillo.
Early abnormalities related to postinfarction Wallerian degeneration: evaluation with MR diffusion-weighted imaging.
PURPOSE: Wallerian degeneration (WD) is most commonly seen after cerebral infarctions and results in persistent neurological deficits. MRI may detect changes related to WD as early as 4 weeks after the insult. We sought to determine if MR diffusion-weighted imaging (DWI) detects changes of WD during the acute period that follows a cerebral infarction. METHOD: Eleven patients with cerebral infarctions underwent DWI within 72 h of the onset of symptoms. DWI was performed using a high diffusion gradient strength (B = 1,000) in a single axis and trace imaging. We reviewed all images with special attention to the signal intensity in the location of the corticospinal tracts. RESULTS: Ten patients harbored 11 middle cerebral artery (MCA) infarcts, and one patient had an anterior cerebral artery (ACA) infarction. Only one patient with an MCA infarct showed a subtle abnormality in the ipsilateral corticospinal tract. The patient with the ACA infarct showed an abnormality in the region of the corticopontine tract. CONCLUSION: As used in this study, DWI depicted presumed early WD in only 20% of instances.
Acute Disease↗
Contrast-enhanced 3D FISP MR angiography of the aortic arch ostia: preliminary results.
PURPOSE: The goal of this work was to evaluate three-dimensional (3D) contrast-enhanced MR angiography (MRA) for the detection of ostial stenoses of the aortic arch. METHOD: Sixteen patients with suspected carotid atherosclerotic disease prospectively underwent digital subtraction angiography of the aortic arch followed by contrast-enhanced MRA using a 3D fast imaging with steady-state precession (FISP) technique (TR = 5 ms, TE = 2 ms, flip angle = 30 degrees). Three neuroradiologists blindly measured stenoses on the catheter angiograms and MRA. Evaluation included the ostia of the innominate, left carotid, and left subclavian arteries. Any significant disagreement on catheter angiography was resolved by consensus. The MRA grades of each of the three observers were then compared with the consensus grades of the contrast angiogram. RESULTS: Forty-eight vessels were scored, of which five had significant stenoses. MRA demonstrated 100% sensitivity, 89% specificity, 52% positive predictive value, and 100% negative predictive value. The Bowker test for symmetry indicated no significant difference between conventional angiography and MRA scores (p = 0.32-0.75), and there was good agreement between the three observers (weighted kappa = 0.75-0.86). CONCLUSION: Contrast-enhanced 3D FISP MRA may be a useful imaging modality for the detection of significant stenoses at the ostia of the major aortic arch branches.
Adult↗
Craniovertebral junction tuberculosis: a review of 29 cases.
PURPOSE: The purpose of this work was to describe the various imaging findings in craniovertebral tuberculosis and the importance of imaging in treatment in these patients. METHOD: A retrospective review of MR and CT scans in 29 patients with craniovertebral tuberculosis was performed. The images were reviewed, paying special attention to both bony (skull base, atlas, and axis) and soft tissue involvement in addition to atlantoaxial dislocation, lateral subluxation of the dens, and compression of the spinal cord. RESULTS: Suboccipital pain with neck stiffness was the most common presenting symptom in our patients. The skull was involved in 19 of the 29 cases, clivus involvement was seen in 11 patients, and occipital condyle involvement was present in 14 patients. Detailed analysis of atlas involvement due to tuberculosis showed the lateral masses to be predominantly affected. The dens was involved in 18 cases (62%). Soft tissue masses in the prevertebral area were seen in 22 patients, paravertebral in 27 patients, and epidural involvement in 25 patients was identified. Atlantoaxial displacement was present in seven cases, lateral mass-dens subluxation in five, and superior subluxation of the dens through the foramen magnum compressing the medulla was seen in two cases. Spinal cord compression with intrinsic cord changes was noted in 12 cases. All patients received multidrug antituberculous therapy for 1 year. The presence of neurologic deficit and instability of the atlantoaxial complex was pivotal in further management in these patients. CONCLUSION: A high degree of clinical suspicion is necessary when confronted with patients with neck stiffness and tenderness over the upper cervical vertebrae. MRI in these patients provides a sensitive method for the diagnosis of craniovertebral tuberculosis.
Abscess↗
Acute neck infections: prospective comparison between CT and MRI in 47 patients.
PURPOSE: The purpose of this work was to assess the advantages and disadvantages of MRI versus CT in the initial evaluation of acute infections involving the neck. METHOD: We prospectively evaluated 47 patients with neck infections. All patients underwent CT and MRI with contrast of the area of interest using similar slice thickness. Final diagnosis was achieved by percutaneous aspiration, surgical exploration and drainage, or follow-up after successful antibiotic therapy in all patients. Two radiologists reviewed all imaging studies with special attention to lesion conspicuity, location, extension, bone involvement, source of infection (odontogenic versus nonodontogenic), and presence of gas and/or calcium in the lesions. A 3 point scale was used to grade these parameters, and statistical comparison was done using paired t test. RESULTS: As used in our population, MRI was superior to CT in regard to lesion conspicuity, number of anatomic spaces involved, extension, and source. Additionally, although not statistically significantly, MRI detected a greater number of abscess collections. CT was superior to MRI in the detection of intralesional gas and calcium and showed fewer motion artifacts. These advantages of CT were, however, not significantly better than those of MRI. CONCLUSION: As used in our study, MRI was considered superior to CT in the initial evaluation of neck infections. Our findings suggest that MRI may be used as the first and perhaps the only modality to initially evaluate patients with neck infections when clinically feasible.
Acute Disease↗
Localization of acyl-coenzyme A: cholesterol acyltransferase in villus and crypt cells of chick intestine.
Endogenous cholesterol esterification by acyl-CoA:cholesterol acyltransferase (EC 2.3.1.26) was studied in isolated enterocytes obtained from chick duodenal, jejunal, and ileal villi and crypts, using [14C]oleoyl-CoA as substrate. The maximal specific activity in each cell fraction was found in chick jejunum, followed by duodenum and ileum. Jejunal upper and mid villi showed higher specific activities than lower villi and crypts. Epithelial cells isolated from chick intestine also incorporated oleoyl-CoA into different lipids using the endogenous substrates. Upper and mid villus cells showed the maximal incorporation of oleoyl-CoA into triglycerides in duodenum and jejunum. Levels of oleoyl-CoA incorporation into phospholipids were higher than those found in the synthesis of triglycerides or cholesterol esters, whatever may be the cell fraction considered. Upper villus cells also showed the highest specific activity in the incorporation of oleoyl-CoA into phospholipids. The acyl-CoA hydrolase specific activity was practically similar in all the cell fractions obtained from chick duodenum, jejunum, and ileum.
Animals↗
CT evaluation of prosthetic ossicular reconstruction procedures: what the otologist needs to know.
Postoperative otologic evaluation of patients who have undergone ossicular reconstruction is often difficult. However, thin-section computed tomography (CT) can help determine the type of prosthesis used for reconstruction and adequately assess for complications that may be causing postoperative conductive hearing loss. A variety of prostheses may be used in ossicular reconstruction (eg, stapes prosthesis, incus interposition graft, Applebaum prosthesis, Black oval-top prosthesis, Richards centered prosthesis, Goldenberg prosthesis) and can usually be identified at CT by their shapes and locations. Several causes of prosthetic failure are readily demonstrated at CT, including recurrent cholesteatoma and otitis media, formation of granulation tissue or adhesions, and various mechanical problems (eg, subluxation, dislocation, extrusion, fracture, bending). Perilymphatic fistula can be difficult to identify at CT but may be suggested by the presence of pneumolabyrinth, unexplained middle ear effusion, or fluid accumulation within the mastoid air cells. The presence of soft tissue within the oval window niche 4-6 weeks following surgery may indicate poststapedectomy granuloma or fibrosis. Familiarity with the normal and abnormal CT appearances of ossicular prostheses will enable the radiologist to assist the otologist in identifying patients in whom revision surgery is most appropriate.
Equipment Failure Analysis↗
Effects of hypoxia on retinal pigmented epithelium cells: protection by antioxidants.
Age-related macular degeneration and other eye diseases, such as diabetic retinopathy, are probably linked to the effects of oxygen radicals derived from light or metabolic reactions. We have investigated the effects of hypoxia on bovine retinal pigmented epithelial cells (RPE) and the response of these cells to two antioxidants that have previously shown a beneficial action against free radical-linked senescent involution. The main results of the study were as follows: (i) Hypoxia induced apoptotic damage on RPE cells, with LDH leakage and ATP reduction; (ii) both vitamin C (VC) and N-acetyl-cysteine (NAC) treatment protected against hypoxia-induced apoptosis, with less DNA fragmentation. In our opinion, these findings justify further experimental and clinical work to investigate the role of hypoxia in the mechanisms of age-related RPE injury and death as well as the potential of antioxidant administration to prevent or delay retinal degenerative processes caused by oxygen-dependent pathophysiological conditions.
Acetylcysteine↗
Atypical healed stress fracture of the fibula masquerading as chronic osteomyelitis. A case report of magnetic resonance distinction.
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Chronic Disease↗
Metabolic alterations after a two-hour nocturnal interruption of a continuous subcutaneous insulin infusion.
In order to evaluate the metabolic consequences of a 2-h nocturnal interruption of continuous subcutaneous insulin infusion (CSII), seven insulin-dependent diabetic patients without residual insulin secretion were investigated. The changes in blood glucose, plasma free insulin, glucagon, free fatty acids, and 3-hydroxybutyrate (3 OH-B) concentrations have been compared during two randomized tests carried out either during the normal functioning of a Mill-Hill pump from 10 p.m. to 8 a.m. (1.00 +/- 0.06 U insulin/h, keeping adequate metabolic control) or during the same conditions but with a deliberate arrest of the pump between 11 p.m. and 1 a.m. Considering the value recorded at 11 p.m. as reference, interruption of the insulin infusion resulted in: (1) a rapid (already significant after 1 h) and sustained (maximal fall: --12.5 +/- 2.5 mU/L at 3 a.m.) decrease in plasma free insulin; (2) a delayed (significant after 4 h) and linear rise in blood glucose (maximal increase: + 4.0 +/- 1.3 mmol/L at 5 a.m.); (3) an early (significant at midnight) and prolonged rise in plasma free fatty acids (+ 387 +/- 148 mumol/L at 3 a.m.); (4) a delayed (significant after 3 h) and sustained increase in plasma 3 OH-B (+ 347 +/- 88 mumol/L at 3 a.m.); and (5) no significant changes in plasma glucagon. Thus, a 2-h interruption of CSII in resting nocturnal conditions is sufficient to induce significant, delayed, and sustained metabolic alterations in C-peptide-negative patients despite good baseline blood glucose control. Resetting the pump at its basal rate is insufficient to quickly restore adequate circulating insulin levels and effectively counteract the metabolic disturbances. The efficacy of a bolus insulin injection in these conditions should be evaluated.
3-Hydroxybutyric Acid↗
Characterization of chick serum lipoproteins isolated by density gradient ultracentrifugation.
Serum lipoproteins from 12h fasted male chicks (15-day-old) were separated into 20 fractions by isopycnic density gradient ultracentrifugation. A new procedure was described by collecting the different fractions from the bottom of tube instead of by aspiration from the meniscus of each tube. Analyses of chemical composition of serum lipoproteins have permitted to reevaluate the density limits of major classes: VHDL, d greater than 1.132 g/ml; HDL, d 1.132-1.084 g/ml; LDL, d 1.084-1.038; IDL, d 1.038-1.022; and VLDL d less than 1.022. HDL fractions clearly predominated (approx. 77% of total lipoproteins) while IDL and VLDL were present at low percentage. LDL was the fraction richest in cholesterol; triacylglycerol content clearly increased from HDL to VLDL, while protein content decreased. All the chemical components of chick serum lipoproteins were accumulated in HDL, although triacylglycerol was relatively distributed in all the lipoprotein classes.
Animals↗
Induction in Gallus domesticus of experimental hypercholesterolemia by saturated fat. Effects on cholesterogenic enzyme activity.
The effect of coconut oil supplementation to the diet (10 or 20%) on lipid levels in plasma and liver as well as on the cholesterogenic enzyme activity were studied in 14-day-old chicks. Treatments for 1 or 2 weeks did not interfere in the growth rate of animals nor in the liver weight. The 10% coconut oil group showed a significant increase of plasma cholesterol after 2 weeks of treatment, while after 1 week the increase was not statistically significant. The 20% coconut oil group increased plasma cholesterol from the first week. Triacylglycerol content increased after each coconut oil supplementation to the diet during the first week. Hepatic cholesterol did not change significantly after any treatment assayed. No significant difference was observed in the cholesterogenic activity, measured as hepatic 3-hydroxy-3-methylglutaryl-CoA reductase, so that this study provides a perfect model of hypercholesterolemic animals without changes in their cholesterogenic ability.
Animals↗
Influence of protein/lipid ratio of diet on cholesterol synthesis and esterification in eel liver.
The effect of protein/lipid ratio of diets on hepatic cholesterol has been studied in European eel and correlated with changes in the main enzymes responsible for cholesterol metabolism. The growth rates of animals were similar when dietary lipid level was 12%. However, a 25% protein/20% fat (25/20) diet produced a decrease in the weight gain when compared with that observed after feeding a 30/20 diet. At low fat level (12%), the decrease in dietary protein produced a little but significant increase in total cholesterol, mainly due to the esterified form. On the contrary, a 25/20 diet produced a lower cholesterol accumulation than that a 30/20 diet. These results suggest that a minimal protein level was required for an optimal utilization of dietary fat for cholesterol deposition in liver. No significant differences were found in 3-hydroxy-3-methylglutaryl-CoA reductase, mevalonate kinase, mevalonate 5-phosphate kinase and mevalonate 5-pyrophosphate decarboxylase when compared the effect of 40/12 and 30/12 diets as well as that of 30/20 and 25/20 diets, suggesting that differences in hepatic cholesterol content were not due to differences in cholesterol synthesis but in the transport to the liver. Changes in the esterified cholesterol were parallel to those found in acyl-CoA: cholesterol acyltransferase, corroborating the main role of this enzyme in the regulation of hepatic cholesterol esterification.
Acyl Coenzyme A↗
Diffusion-weighted MR imaging of global cerebral anoxia.
BACKGROUND AND PURPOSE: Diffuse cerebral anoxia is a devastating event, and its acute findings, as revealed by conventional MR imaging and CT scanning, may be subtle. We analyzed diffusion-weighted and conventional MR images of patients with diffuse cerebral anoxia to determine their usefulness in establishing the diagnosis during the acute period and in determining the age of insult. METHODS: We reviewed 11 MR imaging studies of 10 patients who had experienced prolonged cardiac arrest. All of the patients underwent echo-planar diffusion-weighted imaging with low- and high-strength B values and multiplanar unenhanced MR imaging. We considered bright areas on the high-strength diffusion-weighted images to be abnormal when compared with low-strength images. Special attention was given to the cortex, basal ganglia, thalami, hippocampi, cerebellum, and white matter. Conventional MR studies also were reviewed, and abnormalities noted. The medical records of all of the patients were reviewed. RESULTS: Four patients who underwent imaging during the acute period (<24 hours) had bright basal ganglia (n = 2), bright cerebellum (n = 3), and bright cortex (n = 1) shown on their diffusion-weighted images. For these patients, conventional MR images showed questionable increased T2-weighted signal intensity in the basal ganglia (n = 1), and the results of two studies were judged to be normal. During the early subacute period (24 hours-13 days), four patients were studied, and were determined to have an abnormal cortex (n = 3) and basal ganglia (n = 2). For two of these patients, conventional MR images showed similar abnormalities, and the results of one study were normal. For two patients who underwent imaging during the late subacute period (14-20 days), diffusion-weighted images showed abnormalities mostly confined to white matter. Two patients who underwent imaging during the chronic phase (>21 days) had normal results of their diffusion-weighted imaging and one had evidence of laminar necrosis revealed by conventional MR imaging. CONCLUSION: During the acute period, high-strength diffusion-weighted images showed the abnormal basal ganglia, cerebellum, and cortex to a better extent than did conventional MR images. During the early subacute period, gray matter abnormalities were seen on diffusion-weighted images. During the late subacute period, diffusion-weighted images showed mostly white matter abnormalities. During the chronic stage, the results of diffusion-weighted imaging were normal. Our findings suggest that diffusion-weighted images are helpful for evaluating and dating diffuse cerebral anoxia, and therefore aid in the determination of prognosis and management of these patients.
Adolescent↗
Juvenile retinoschisis: imaging findings.
We present the CT and B-scan sonographic findings in an infant with juvenile retinoschisis, a rare hereditary eye disease, which usually follows an X-linked recessive inheritance pattern.
Humans↗
Midline spinal cord hamartomas: MR imaging features of two patients.
Congenital midline spinal hamartomas are relatively rare. Patients harboring this anomaly are generally asymptomatic, but present with an overlying skin anomaly. MR imaging depicts a mass that is isointense with the spinal cord on all sequences, and may show a dermal sinus tract that tethers the cord at the level of the lesion. We report the MR features of congenital midline spinal hamartoma in two children.
Child↗
Effects of contrast material on single-volume proton MR spectroscopy.
BACKGROUND AND PURPOSE: Administration of contrast material before proton MR spectroscopy may allow more accurate placement of the volume of interest, particularly in tumors; yet, some data have suggested that contrast material may alter the results of MR spectroscopy. To determine the validity of this contention, we performed pre- and postcontrast MR spectroscopy in patients with brain tumors and compared the results with those obtained from a phantom. METHODS: Ten patients with astrocytomas were examined with single-volume MR spectroscopy before and after administration of contrast material. Voxel placement was identical for all studies. Peak area, peak height, and width at half maximum were measured for N-acetyl aspartate (NAA), creatine (Cr), and choline (Cho) in all studies. A phantom containing a 10 mmol concentration of NAA, Cr, and Cho was prepared in phosphate-buffered saline and mixed with contrast concentrations varying from 0.1 to 1.0 mmol. The phantom was studied by MR spectroscopy with the same parameters as used for the clinical studies. RESULTS: No significant differences were found between the pre- and postcontrast MR spectroscopy studies for the three parameters measured. In phantom studies, there was a significant decline in the Cho peak area and height and an increase in the width at half maximum as the concentration of contrast material increased from 0.1 to 1.0 mmol. NAA and Cr peaks showed no significant changes in peak height or area. CONCLUSION: Contrast material may be administered before clinical MR spectroscopy without affecting its interpretation.
Aspartic Acid↗
Diffuse leptomeningeal oligodendrogliomatosis: radiologic/pathologic correlation.
We present the radiologic and pathologic findings in a boy who presented with diffuse leptomeningeal enhancement and whose clinical status deteriorated over the course of 5 years. During this period, MR images showed progression of the enhancement in the subarachnoid spaces, formation of intraaxial cysts, and hydrocephalus. Autopsy findings revealed diffuse oligodendroglioma throughout the leptomeninges of the brain and spine, with no definite intraaxial focus. The radiologic and pathologic features of diffuse leptomeningeal oligodendrogliomatosis are reviewed.
Brain↗