Search PubMed⌕ Search

Biomedical subjects

M M Teng

Publications and source records attributed to M M Teng.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Embolization of an arteriovenous fistula in the posterior fossa: report of a case].

We report a case of posterior fossa arteriovenous fistula with a possible arterial aneurysm. The patient was a 15-year-old female. She was transferred to us because of a sudden onset of dyspnea, severe headaches, and loss of consciousness. The CT scan found an abnormal vascular lesion in the posterior fossa. Calcification was noted in the wall of the largest abnormal vascular structure. The angiogram showed a focal aneurysmal dilatation of the hemispheric branch of the right posterior inferior cerebellar artery, followed by an arteriovenous fistula, which drained to the right transverse sinus. Embolization was performed by implanting a detachable balloon into the proximal end of the aneurysm. These abnormal vascular structures disappeared completely on the angiogram after the embolization. CT scan one week after embolization showed increased density in these abnormal vascular structures, with no enhancement after contrast, indicating thrombosis or the formation of a blood clot in their lumen. The CT half a year after embolization showed reduction in size and a low density change in the largest vascular structure with calcification in the wall. All other abnormal vascular structures disappeared. An angiogram half a year after the embolization confirmed no recurrence of the aneurysm or arteriovenous fistula.

Adolescent↗
PubMed1990

CT evaluation of polymorphic reticulosis.

For the understanding of the CT findings of polymorphic reticulosis involving the upper respiratory tract, we reviewed eleven cases of this disease with initial CT study before treatment. CT revealed masses or swelling in the nose or nasal chamber, often with involvement of paranasal sinuses and medial parts of the orbit. In some, nonspecific minimal bony change (either bone destruction or bone sclerosis) was found. These CT findings are not specific. Any large mass in the nose and nasal fossa with little associated bone destruction should, however, raise the differential diagnosis of polymorphic reticulosis.

Adolescent↗
PubMed1989

CT of pineal tumors and intracranial germ-cell tumors.

We reviewed 59 cases of pineal tumors and intracranial germ-cell tumors. Most pineal tumors occurred in the first three decades of life, with the exception of pineocytomas, which were seen at a mean age of 34. A male preponderance was noted in the various pineal tumors, except for pineocytomas. The most common tumor of the pineal region was germinoma, which usually showed high density with homogeneously intense enhancement after IV administration of contrast medium. An increased prevalence of pineal calcification was also a feature of pineal germinomas. No characteristic CT features could be found to differentiate among pineal choriocarcinoma, germinoma, embryonal carcinoma, yolk-sac tumor, pineocytoma, and pineoblastoma. CT is useful in detecting intracranial tumors, but the definite diagnosis should depend on pathologic examination and detection of tumor markers in the serum and CSF.

Adolescent↗
PubMed1988

Ocular bruits in ischemic cerebrovascular disease.

A total of 72 ocular bruits in 50 patients with symptoms of atherothrombotic ischemic cerebrovascular disease were studied with continuous-wave Doppler ultrasonography with spectrum analysis (Dopscan). Fourteen patients also had conventional angiography, and 14 had digital subtraction angiography. Ocular bruits by augmentation flow due to occlusion (seven bruits, 9.7%) or tight stenosis (17 bruits, 23.6%) of the contralateral internal carotid artery accounted for only 24 ocular bruits (33.3%). In contrast, siphon stenosis ipsilateral to the ocular bruit was a very common finding. All 14 patients studied with conventional angiography had variable degrees of siphon stenosis ipsilateral to the ocular bruits; there was one angiography failure. We conclude that siphon stenosis can cause ocular bruit alone or can act in combination with augmentation flow by contralateral carotid occlusion or tight stenosis. The difference in their relative occurrence in our patients compared with previous reports probably reflects racial differences in the distribution of stenotic or occluded lesions of the carotid artery between our patients and Caucasian patients. The ocular bruit was the only auscultatory finding in more than a quarter of our patients (14 of 50, 28%).

Aged↗
PubMed1988

Direct puncture of the cavernous sinus for obliteration of a recurrent carotid-cavernous fistula.

The authors report direct transcutaneous puncture of the cavernous sinus through an intact orbit for embolization of a recurrent carotid-cavernous fistula (CCF) after 10 prior operations. The fistula was obliterated completely with this technique. No significant complication was noted except temporary ptosis for about 2 months. When other approaches are difficult or impossible, this technique can be an alternate way to treat a recurrent CCF after a trapping procedure.

Adult↗
PubMed1984

Ankle tenography: a key to unexplained symptomatology. Part I: Normal tenographic anatomy.

Fifty cadaver ankles were examined with ankle tenography. The normal tenographic appearance of the peroneus longus and brevis, posterior tibial, flexor digitorum longus, flexor hallucis longus, anterior tibialis, extensor hallucis longus, and extensor digitorum longus tendons and sheaths are described and illustrated for clinical reference. The baseline measurements and demonstration of the normal radiographic appearance of these tendons should assist in the evaluation of hindfoot foot disability and ankle pain.

Ankle↗
PubMed1984

Elbow arthrography: a reassessment of the technique.

Twenty-six elbow arthrograms were retrospectively reviewed. Each arthrogram consisted of conventional radiography, conventional tomography, standard double-contrast arthrography, and arthrotomography. Each of these four components was independently interpreted in a blinded fashion by six radiologists, each working alone. The four components were evaluated for presence or absence of intraarticular bodies, cartilage loss, or fractures. The results showed that conventional tomography was the most accurate single study. Arthrotomography rarely improved the diagnostic accuracy of noncontrast methods. It was useful in those few patients where detection of purely cartilaginous bodies, precise position of mineralized densities, or status of articular cartilage was desired. It may be possible to reduce the number of elbow arthrograms, thereby reducing time, cost, and radiation dose factors.

Adolescent↗
PubMedDate not supplied

Dynamic MR imaging of hepatolithiasis.

BACKGROUND: To report the dynamic magnetic resonance (MR) imaging findings of hepatolithiasis. METHODS: Dynamic MR images (fast spoiled gradient echo sequence with intravenous injection of gadopentate dimeglumine) and computed tomography, cholangiography, or angiography of nine patients with hepatolithiasis are analyzed. RESULTS: All affected hepatic segments showed atrophic changes and contained dilated intrahepatic ducts. These segments showed either iso- or hypointensity on T1-weighted imaging and hyperintensity on T2-weighted imaging. Preferential enhancement was noted throughout all phases of the dynamic study and persisted to delayed T1-weighted imaging in seven patients. In the last two patients, severe atrophic changes made evaluating signal intensity differences and enhancement patterns difficult. CONCLUSION: In addition to intrahepatic stones and biliary dilatation, segmental atrophy, signal intensity differences, and preferential and persistent enhancement are important MR findings of hepatolithiasis.

Adult↗
PubMedDate not supplied

CT and myelogram findings of os odontoideum.

We reviewed the findings of CT and myelogram of cases of os odontoideum. The diagnosis was confirmed by conventional tomogram in all these cases. Four cases were further confirmed by trans-oral decompression. Cartilage was found between the os odontoideum and the odontoid process during operation in these 4 cases. Four of them had no history of trauma and 2 of them had an associated anomaly; one was Down's syndrome, and the other was barrel chest and congenital dislocation of hips. CT findings of os odontoideum in these cases were a constriction and/or a gap of bony structure between the os odontoideum and the odontoid process. Myelograms showed spinal stenosis as a result of atlanto-axial dislocation, or anterior extradural compression from overgrown cartilage and posteriorly dislocated tip of shortened odontoid process.

Adolescent↗
PubMedDate not supplied

MR perfusion studies of brain for patients with unilateral carotid stenosis or occlusion: evaluation of maps of "time to peak" and "percentage of baseline at peak".

Maps of "time to peak" (TTP) and "percentage of baseline at peak" (PBP) were compared with maps of conventional brain perfusion parameters, namely, mean transit time (MTT) and relative cerebral blood volume (rCBV). We performed MR perfusion studies in 11 patients. All of them had occlusion or high-grade stenosis of the unilateral carotid artery. Three areas of old infarct, 4 areas of new infarct, and 10 areas of brain without infarct were evaluated specifically. In all these cases, the TTP maps appeared similar to the MTT maps. They showed increases, normal values, or decreases at the same time in all areas evaluated. Most areas of abnormally decreased CBV had increased signal in PBP maps. In conclusion, the TTP map provided the same qualitative information as MTT. PBP seemed correlated inversely to CBV and was less sensitive in demonstrating abnormality.

Aged↗
PubMedDate not supplied

CT of pineal tumors and intracranial germ-cell tumors.

We reviewed 59 cases of pineal tumors and intracranial germ-cell tumors. Most pineal tumors occurred in the first three decades of life, with the exception of pineocytomas, which were seen at a mean age of 34. A male preponderance was noted in the various pineal tumors, except for pineocytomas. The most common tumor of the pineal region was germinoma, which usually showed high density with homogeneously intense enhancement after IV administration of contrast medium. An increased prevalence of pineal calcification was also a feature of pineal germinomas. No characteristic CT features could be found to differentiate among pineal choriocarcinoma, germinoma, embryonal carcinoma, yolk-sac tumor, pineocytoma, and pineoblastoma. CT is useful in detecting intracranial tumors, but the definite diagnosis should depend on pathologic examination and detection of tumor markers in the serum and CSF.

Adolescent↗
PubMedDate not supplied

The pituitary mass after transsphenoidal hypophysectomy.

To understand the natural changes in the CT appearance of a pituitary mass after transsphenoidal hypophysectomy of a pituitary tumor, we obtained CT follow-up studies in 12 patients with pituitary adenoma. The heights of the pituitary masses on the coronal sections of each CT study were measured. It was found that the height of the pituitary mass did not return to normal immediately after the operation, despite complete removal of the pituitary tumor. Instead, the height gradually returned to normal between 3 and 4 months after the operation. Results of this study suggest that follow-up CT study of pituitary masses is best performed 3-4 months after transsphenoidal hypophysectomy.

Adenoma↗
PubMedDate not supplied

Occlusion of arteriovenous malformations of the cavernous sinus via the superior ophthalmic vein.

The treatment of five patients with dural arteriovenous malformations (AVMs) of the cavernous sinus via the superior ophthalmic vein (SOV) is reported. The procedure was performed by transcutaneous puncture of the SOV under the guidance of real-time digital subtraction angiography. Complete resolution of the ocular symptoms was achieved in all cases. Angiograms after embolization showed complete obliteration of the malformation in four cases and partial obliteration in one. This method can cure dural AVMs of the cavernous sinus, with preservation of blood flow in the internal carotid artery. It is particularly indicated when the SOV is enlarged and when (1) dural AVMs of the cavernous sinus are fed by small branches of the internal carotid artery or direct carotid cavernous fistulas with small tears; (2) dural AVMs of the cavernous sinus are fed by multiple branches from both the internal and external carotid arteries, one or both sides; or (3) dural AVMs of the cavernous sinus or direct carotid cavernous fistulas recur after trapping of the internal carotid artery. Transcutaneous puncture and catheterization of the SOV was performed safely with the aid of digital subtraction angiography. The SOV approach was able to treat the fistula with preservation of the internal carotid artery.

Adult↗
PubMedDate not supplied

Chorea-ballismus with nonketotic hyperglycemia in primary diabetes mellitus.

PURPOSE: To describe the neuroimaging (Ct, MR, and single-photon emission CT [SPECT]) findings in a series of patients with chorea-ballismus associated with nonketotic hyperglycemia in primary diabetes mellitus and to correlate the imaging findings with the clinical presentation. METHODS: The neuroimaging and clinical data from 10 patients with chorea-ballismus associated with nonketotic hyperglycemia in primary diabetes mellitus were evaluated. Family and drug histories, as well as other causes of chorea, were excluded. All 10 patients had CT, 5 also had MR imaging, and 3 had SPECT examinations. Three had follow-up CT and MR imaging studies, and MR findings were correlated with CT findings in 5 cases. Two experienced neuroradiologists, aware of the diagnosis but blinded to the clinical status of the patients, evaluated all images and reached a consensus as to the final interpretation. RESULTS: CT studies in 9 of 10 patients showed a hyperdense putamen and/or caudate nucleus; in 1, the CT findings were normal. T1-weighted MR images in all 5 patients who had MR imaging (including the patient with a normal CT study) showed hyperintense lesions without significant T2 signal alternation at the basal ganglia. In all 3 of the patients who had SPECT studies of the brain, the scans revealed hypoperfusion at corresponding areas. All 3 follow-up studies depicted resolution of the lesions in the abnormal basal ganglia. Increased hypointensity on T2-weighted and gradient-echo T2*-weighted images was also observed in the sequential MR images. In all patients, the initial side of involvement correlated well with the neuroimaging findings. The chorea resolved within 2 days after treatment of the hyperglycemia in 9 patients. CONCLUSION: In patients with chorea-ballismus associated with nonketotic hyperglycemia in primary diabetes mellitus, CT and T1-weighted MR images show unilateral or bilateral lesions of the putamen and/or caudate. SPECT scans show hypoperfusion. These findings may be related to petechial hemorrhage and/or myelin destruction. Early recognition of these imaging characteristics may facilitate diagnosis of primary diabetes mellitus with hyperglycemia and prompt appropriate therapy.

Aged↗