MR-guided aspiration and drainage of a nasopharyngeal mucus retention cyst.
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Adult↗
Biomedical subjects
M H Han
Publications and source records attributed to M H Han.
Sinonasal psammomatoid ossifying fibromas: CT and MR manifestations.
Five cases of pathologically proved psammomatoid ossifying fibromas of the sinonasal area are presented. All five cases were examined by CT and in three cases MR imaging was performed before and after injection of gadopentetate dimeglumine. The lesions were located in the sphenoethmoidal area and extended over the nasal cavity or orbit in four cases. In one case, the lesion occurred at the perpendicular plate of the ethmoid bone with preservation of the ethmoidal sinus. On CT, all the lesions were expansile and circumscribed by a thick bony wall. Internal septations of bone density (four cases) or enhancing soft-tissue density (one case) were seen and internal content was low in density in all but one from which blood was aspirated. On MR, the bony walls were isointense with gray matter on T1-weighted images and were seen as areas of low intensity on T2-weighted images. The lesions significantly enhanced after injection of contrast material. A well-circumscribed multiloculated expansile mass with a thick wall of bone density on CT scans and enhancement of this area on postcontrast MR images is strongly suggestive of psammomatoid ossifying fibroma.
Adolescent↗
The role of contrast-enhanced MR imaging in the diagnosis of neurocysticercosis.
Pre- and postcontrast MR images of 17 patients with the diagnosis of neurocysticercosis were reviewed to evaluate the role of gadopentetate dimeglumine in MR imaging of this disease. The MR images, which were obtained on either a 0.5-T or 2.0-T superconducting system, revealed a total of 92 cysticerci in 17 patients. On contrast-enhanced T1-weighted images, 23 parenchymal cysticerci showed contrast enhancement. Ring-shaped enhancement was seen in only 6% (3/54) of cysticerci with intensity paralleling the CSF, while it was noted in 67% (16/24) of the cysticerci with intensity higher than CSF. Nodular enhancement was seen in granulomatous lesions with surrounding edema (29%, 4/14). Of 18 cysticerci with surrounding edema, 17 showed contrast enhancement. Basal meningeal enhancement, indicating meningitis, was observed in three patients. The results indicate that contrast enhancement usually occurs in patients in whom precontrast MR findings have shown active inflammatory reaction in the degenerating stage of the worm. Thus, postcontrast imaging is useful in a limited number of patients with neurocysticercosis; it should be used selectively in those whose clinical or precontrast MR studies show meningitis, granulomatous lesions, or cysts with surrounding edema.
Adult↗
Gd-DTPA-enhanced MR imaging of the brain in patients with meningitis: comparison with CT.
Plain and Gd-DTPA-enhanced MR images of the brain were obtained in 18 consecutive patients with meningitis (eight with tuberculous, five with bacterial, three with viral, and two with fungal infections); the MR images were compared with CT scans. MR images were obtained on a 2.0-T superconducting unit with both T1- and T2-weighted pulse sequences before injection and with a T1-weighted sequence after injection of Gd-DTPA (0.1 mmol/kg) in all patients. In tuberculous meningitis, MR imaging depicted ischemia/infarct, hemorrhagic infarct of basal ganglia, meningeal enhancement at either basal cistern or convexity surface of brain, and associated small granulomas in a few more patients than CT did. In bacterial meningitis, primary foci of extracranial inflammation (i.e., mastoid, paranasal sinuses) and adjacent intracranial lesions including localized dural inflammation, subdural fluid collection, and/or brain parenchymal lesions were demonstrated much better on MR than on CT. Otherwise, MR images generally matched the CT scan. Although the plain MR images, both T1- and T2-weighted, were the most sensitive in delineating ischemia/infarct, hemorrhage, and edema, they were not as specific as Gd-DTPA-enhanced T1-weighted images and postcontrast CT scans in defining the active inflammatory process of the meninges and focal lesions precisely. We conclude that if Gd-DTPA is used, MR imaging appears to be superior to CT in the evaluation of patients with suspected meningitis. Precontrast MR is needed to delineate ischemia/infarct, edema, and subacute hemorrhage.
Adolescent↗
Tuberculous arachnoiditis of the spine: findings on myelography, CT, and MR imaging.
Tuberculosis (TB) is a rare cause of spinal arachnoiditis. It may occur primarily or secondary to intracranial or vertebral infection; unlike other types of arachnoiditis, it frequently involves the spinal cord as well as the meninges and the nerve roots. We retrospectively reviewed 13 conventional myelograms, eight CT myelograms, and five Gd-DTPA-enhanced MR images in 13 patients with spinal TB radiculomyelitis (arachnoiditis). Eleven patients had intracranial TB meningitis at the time of diagnosis or before. Ten patients were less than 30 years old. Conventional myelographic findings included a block of the CSF (11/13), most commonly at the level of the conus medullaris; irregular or indistinct thecal sac contour (9/13); multiple fine and/or coarse nodular defects (8/13); nerve-root thickening (7/13); and vertical bandlike adhesive defects (4/13). CT myelography showed intradural nodular masses suggesting tuberculomas at or just above the level of the block (4/8), irregularity of the spinal cord surface (4/8), irregular filling or obliteration of subarachnoidal space (6/8), and root thickening (5/8). Gd-DTPA-enhanced MR images revealed enhancing nodules suggesting tuberculomas (2/5); enhancement of the dura-arachnoid complex around the cord (3/5); and segmental enhancement of the thoracic cord, suggesting either infarction caused by vasculitis or TB myelitis in association with diffuse cord swelling (1/5). Plain MR findings were much less conspicuous, showing only an indistinct or irregular dura-arachnoid-cord complex (4/5). In conclusion, the conventional myelographic findings are considered to be virtually diagnostic of spinal TB radiculomyelitis in young patients with antecedent or coexisting TB meningitis.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗