History of pain in the ankles, lower legs, arms, hands, head and face. Case report.
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Bone and Bones↗
Biomedical subjects
R D Tien
Publications and source records attributed to R D Tien.
Correlation of clinical, surgical, pathologic, and MR fat suppression results for head and neck cancer.
Magnetic resonance (MR) imaging provides superior soft tissue delineation of head and neck tumors compared to previous radiologic studies. Further refinements using fat suppression and gadolinium (Gd-DTPA) enhancement have added to these improved images. We performed MR studies of 16 patients with head and neck tumors with detailed clinical, surgical, and pathologic information. MR studies included standard spin-echo T1-weighted images (T1WI) with and without fat suppression and T2-weighted images (T2WI) with fat suppression. Gadolinium was also administered with fat suppression. Conventional and paired fat suppression MR images were compared by a grading system. Post-Gd-DTPA fat suppression T1WI, and T2WI with fat suppression, showed superior sensitivity for tumor delineation when compared to conventional T1WI. Fat suppression T2WI was the best technique to delineate squamous cell carcinoma both in the primary site and regional lymph nodes. Clinical, surgical, and pathologic results correlated perfectly with imaging findings. These refinements in MR imaging represent a significant advance in the radiologic evaluation of head and neck tumors.
Adipose Tissue↗
Quantitation of structural distortion of the cervical neural foramina in gradient-echo MR imaging.
Quantitative errors (due to magnetic susceptibility artifacts) in the measurement of the cervical spinal neural foramina with fast gradient-echo (GRE) magnetic resonance imaging were assessed. Cylindric phantoms of different materials were used to demonstrate the nature of magnetic susceptibility artifacts, emphasizing the dependence of the artifact on tissue geometry. Neural foramina diameters measured on thin, sagittal GRE and spin-echo (SE) images through the neural foramina of a fresh human cervical spine specimen were then compared with direct measurements with calipers. The GRE images showed more apparent narrowing than did the SE images. The absolute distortion of seven neural foramina was rather constant (less than two pixels) on the GRE images; therefore, the relative distortion was inversely proportional to the size of the neural foramen, ranging up to 10% in the upper cervical region at a short TE. The absolute and relative distortion increased as TE increased. At a constant TE, the structural distortion did not change with different TRs or flip angles. The shortest possible TE is recommended in evaluation of the cervical spine.
Artifacts↗
Neuroimaging in epilepsy.
Neuroimaging techniques have improved the understanding, diagnosis, and management of epilepsy. By providing excellent structural information, MRI is the technique of choice in evaluating patients with epilepsy. Functional imaging techniques, including MR spectroscopy, functional MRI, positron emission tomography, and single photon emission CT, permit noninvasive assessment of the epileptic substrate, its functional status, and neuroreceptors. The MRI-based techniques will potentially assume a greater role in the cost-effective workup of the patient. Currently, newer techniques such as magnetoencephalography, magnetic source imaging, and optical imaging are research tools.
Brain↗
Osseous metastasis in medulloblastoma: MRI findings in an unusual case.
An 11-year-old boy with a history of medulloblastoma developed blastic osseous metastases. The metastases were detected by noting diffuse areas of low signal intensity within the calvarium on T1-weighted and T2-weighted magnetic resonance (MR) scans of the brain. The MR appearance of osseous metastases in medulloblastoma has not been reported previously. Extraneural metastases in medulloblastoma are relatively rare. The literature is briefly reviewed.
Bone Neoplasms↗
MR findings of pineal yolk sac tumor in a patient with testicular embryonal carcinoma.
Magnetic resonance imaging features of a rare pineal region yolk sac tumor found in a 31-year-old man with a history of previously treated embryonal cell carcinoma of the testicle are presented. No specific magnetic resonance imaging features that definitely differentiate yolk sac tumor from other pineal region tumors could be found. However, in individuals with a previously established testicular germ cell tumor, a metastatic or secondary primary germ cell tumor should be suspected when there is a newly diagnosed pineal region mass. Serum tumor markers are helpful in confirming the diagnosis of a germ cell tumor.
Adult↗
MR findings in a patient with Ramsay-Hunt syndrome.
A case of Ramsay Hunt syndrome (herpes zoster oticus) was studied with Gd diethylenetriamine pentaacetic acid enhanced magnetic resonance imaging using a surface coil rather than a conventional head coil. This allowed us to demonstrate in detail the inflammatory changes of the multiple structures, involved.
Contrast Media↗
MR fat suppression combined with Gd-DTPA enhancement in optic neuritis and perineuritis.
A fat suppression MR technique used in combination with Gd-DTPA enhancement was investigated to determine its value in cases of inflammatory optic nerve lesions. This technique, the so-called hybrid method, is a derivative of the chopper fat suppression technique and provides water-only images without increasing the imaging or postprocessing time. The study group consisted of four patients with acute visual loss, all of whom received Gd-DTPA. Conventional T2-weighted and fat suppression post-Gd-DTPA T1-weighted images were obtained in all patients; in addition, in one patient a post-Gd-DTPA T1-weighted image without fat suppression was obtained. In three patients, the conventional T2-weighted images failed to reveal any abnormality. In contrast, the enhanced optic nerve and enhanced perineural inflammatory infiltrate were easily identified on T1-weighted images after administration of Gd-DTPA and application of fat suppression technique. The lesions in inflammatory optic neuritis or perineuritis were easily distinguished from the surrounding fat, which had been suppressed. This combined technique resulted in significantly improved definition of normal anatomic structures and made the enhancing lesions more conspicuous, especially in areas with large amounts of fat such as the retrobulbar orbit.
Adipose Tissue↗
CNS mycosis fungoides: CT and MR findings.
Mycosis fungoides (MF) is a malignant T-cell lymphoma that primarily involves the skin, but may, in its advanced stages, metastasize to internal organs. From autopsy series, CNS involvement of MF can be seen in 14% of patients. We describe the CT and MR findings in three patients with CNS metastases. The images showed various manifestations of CNS MF, including parenchymal homogeneously intensely enhancing masses and ependymal enhancement. The CSF and biopsy results were eventually diagnostic in all three cases. One patient was treated prior to pathologic diagnosis, the other two were treated after diagnosis. The tumor improved following treatment in two patients. Although the imaging findings of CNS MF are nonspecific, they can be the first evidence of the disease.
Brain Neoplasms↗
Muslin-induced optic arachnoiditis ("gauzoma"): findings on CT and MR.
We report a case with a paraophthalmic aneurysm that was wrapped with muslin because it was unclippable. Six months after wrapping, the patient developed gradual vision loss involving the ipsilateral eye. Both CT and MR studies demonstrated a loculated fluid collection with marked surrounding enhancement in the region of the previous surgery. Craniotomy revealed an abscess centered in the region of the aneurysmal wrapping. Pathological diagnosis was consistent with a foreign-body reaction with acute and chronic inflammation. Postoperatively the patient showed improvement in vision. We describe the MR findings in this case of muslin-induced optic arachnoiditis ("gauzoma").
Abscess↗
MRI of gangliocytoma of cerebellum and spinal cord.
Gangliocytomas are rare CNS tumors that occur in children and young adults. We present a case of a cerebellar gangliocytoma with invasion of the cervical spinal cord demonstrated on MR. Radiographic differentiation of gangliocytomas from other ganglion cell tumors--ganglioglioma, dysplastic gangliocytoma of Lhermitte-Duclos, and desmoplastic infantile ganglioglioma--is discussed.
Cerebellar Neoplasms↗
Spinal dural arteriovenous fistula: demonstration using phase contrast MRA.
Contrast angiography is the standard means of diagnosing spinal dural arteriovenous fistulas. We present a patient in whom a spinal dural arteriovenous fistula was demonstrated on phase contrast MR angiography.
Angiography↗
Magnetic resonance imaging evidence of hippocampal sclerosis in progression: a case report.
A 32-month-old child presented in status epilepticus (SE) involving the left side of the body. Fast spin-echo magnetic resonance imaging (FSE-MRI) with hippocampal volumetry performed < or = 24 h after the seizure showed increased T2 signal of the right hippocampus, but no atrophy. Complex partial seizures (CPS) appeared at age 33 months, and three more episodes of SE occurred between 33 and 37 months of age. Follow-up FSE-MRI at 34 and at 45 months of age demonstrated progressive hippocampal atrophy with resolution of the increased T2 signal. Her CPS became intractable and, at age 51 months, she underwent right temporal lobectomy. In the ensuing 5 months, she has had only one major motor seizure. This case demonstrates that acute increased hippocampal T2 signal intensity can occur soon after SE and hippocampal sclerosis (HS) may become evident within months in the setting of recurrent early childhood SE. This observation may support the hypothesis that early childhood SE can lead to HS. Furthermore, this case suggests that years of temporal lobe CPS may not be necessary for development of HS.
Brain Diseases↗
Frontal sinus fractures: evaluation of CT scans in 132 patients.
PURPOSE: To determine the frequency of detection of frontal sinus fractures on initial CT scans of patients with intracranial injuries, and to characterize associated injuries. METHODS: The initial head CT scans in 132 patients with clinical or radiographic evidence of a frontal sinus fracture were retrospectively reviewed to further characterize the fracture. Additional radiographic studies and medical records were reviewed to determine associated injuries, therapy, clinical outcome, and complications. RESULTS: In 90% (124) of the patients, the frontal sinus fractures were visualized on initial head CT scans that were obtained to evaluate suspected intracranial injury. Complex fractures involving both the anterior and posterior wall of the sinus accounted for 65% of cases (86 patients), whereas fractures of the anterior wall only or posterior wall only occurred in 24% (32) and 11% (14) of patients, respectively. Significant intracranial hemorrhage occurred in over 90% of patients with fractures involving the posterior wall. CONCLUSIONS: In general, fractures that involved the posterior wall had more complications and a worse clinical outcome than fractures that only involved the anterior wall; nearly all frontal sinus fractures can be detected on head CT studies in patients with intracranial injuries.
Adolescent↗
Meningioangiomatosis: CT and MR findings.
Meningioangiomatosis (MA) is a rare hamartomatous lesion of the cerebral cortex; to date only 18 cases with imaging findings have been reported in the English literature. The origin of MA is probably malformative, with possible association with neurofibromatosis. These lesions frequently cause seizures in young patients. We report two new cases seen at our institution and present their CT and MR findings clearly illustrating MA cortex infiltration. Gd-DTPA used in one of the two cases failed to cause enhancement.
Child↗
Improved detection and delineation of head and neck lesions with fat suppression spin-echo MR imaging.
To compare conventional and fat suppression MR imaging in their ability to detect head and neck lesions, we prospectively studied 17 patients with head and neck tumors and one normal volunteer. Five patients had benign tumors (one mixed cell tumor, one hemangioma, one lipoma, and two plexiform neurofibromas), 10 had malignant tumors (six squamous cell carcinomas, two minor salivary gland carcinomas, one lymphoma, and one malignant fibrous histiocytoma), and two had nonspecific lymphadenopathy. All subjects were studied with standard spin-echo T1- and T2-weighted images (T2-weighted imaging was done with and without fat suppression technique). In addition, T1-weighted images with contrast enhancement and fat suppression were obtained in nine patients. A four-point grading system was used for comparison of the conventional and fat suppression images. Grades ranged from 0 (unsatisfactory, the lesion cannot be seen) to 3 (excellent, the lesion and its margins can be seen clearly with sharp contrast from surrounding normal tissue). We found that postcontrast fat suppression T1-weighted images and fat suppression T2-weighted images were most useful; these sequences obtained an average score close to grade 3 (2.77 and 2.85, respectively). On the other hand, the conventional T2-weighted images had an average score of about 2 (1.82) and the conventional T1-weighted image had a score of about 1 (1.33). Fat suppression T2-weighted sequences generally were superior in cases of lymphadenopathies. Postcontrast T1-weighted images were most useful in a case of plexiform neurofibroma, owing to their fibrous component and lower proton density.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Reduced hypothalamic blood flow after radiation treatment of nasopharyngeal cancer: SPECT studies in 34 patients.
To determine the effect of cranial irradiation on hypothalamic blood flow, we performed 44 regional cerebral blood flow studies with 99mTc hexamethyl propyleneamine oxime (HMPAO) single-photon emission CT (SPECT) on four normal volunteers and 34 patients with pathologically proved nasopharyngeal cancer. Twenty-three men and 15 women, 30-65 years old, were divided into four study groups: group 1 served as a control and consisted of four normal volunteers and six patients studied prior to cranial irradiation; group 2 patients had cranial irradiation half a year before the SPECT study (n = 12, one from group 1); group 3 patients were irradiated 1 year before the study (n = 13, three from group 1 and two from group 2); and group 4 patients were irradiated at least 5 years before SPECT imaging (n = 9). Six patients were studied twice. Quantification of the 99mTc-HMPAO brain SPECT studies was done separately by three radiologists to obtain the hypothalamus/occipital (H/O) and hypothalamus/parasagittal (H/P) ratios. Endocrinologic studies were performed in all cases and the hypothalamus-thyrotroph-thyroid, hypothalamus-gonadotroph-testis (ovary), hypothalamus-lactotroph, hypothalamus-somatotroph, and hypothalamus-corticotroph-adrenal axes were evaluated separately. We determined that regional hypothalamic blood flow was reduced after cranial irradiation in patients with nasopharyngeal cancer. The H/O ratio of groups 3 and 4 did not differ from that of group 2 (one-half year after cranial irradiation). The H/O ratio was significantly reduced 6 months and 1 year after cranial irradiation; mean +/- SD = 0.5801 +/- 0.0829 (p less than .025), 0.5725 +/- 0.0791 (p less than .01) versus 0.6477 +/- 0.0458 before cranial irradiation, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Intra- and paraorbital lesions: value of fat-suppression MR imaging with paramagnetic contrast enhancement.
The orbital area of 18 individuals was examined by using a combination of fat-suppression contrast-enhanced MR imaging to determine whether contrast between fat and surrounding tissues could be improved over that obtained with conventional fat-suppression techniques alone. We used a hybrid technique combining two independent methods of fat suppression. Subjects consisted of 16 patients and two normal volunteers. Fifteen individuals received gadopentetate dimeglumine, and conventional T1-weighted, T2-weighted, and fat-suppression T1-weighted images were obtained. The fat-suppressed T1-weighted images obtained after contrast administration provided more information than did the conventional MR images. Intraorbital and paraorbital lesions could be distinguished easily from intraorbital fat that had been suppressed. Cases of chorioretinitis and optic neuritis could be confidently diagnosed only by this technique. Cases of optic nerve meningioma and mixed conal lesions also were better appreciated. Because of sharp contrast between tissue planes, this technique was helpful for detecting any intraorbital invasion from paraorbital lesions. Fat-suppression MR imaging with paramagnetic contrast enhancement can significantly improve the delineation of both normal and abnormal structures and better define lesional margins in the orbit, where large amounts of fat are present. Our results support earlier findings, and we suggest that postcontrast fat-suppressed T1-weighted imaging be used instead of conventional T1-weighted postcontrast imaging in evaluating orbital and paraorbital lesions.
Adolescent↗