Koshevnikov syndrome in a patient with MELAS plus syndrome: electron microscopic and neuroimage studies.
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Adult↗
Biomedical subjects
K M Huang
Publications and source records attributed to K M Huang.
Magnetic resonance imaging of glomus tumour in the hand.
Glomus tumours of the hand are benign tumours that arise from the neuromyoarterial apparatus. The most common site for a glomus tumour is in the distal phalanx. They frequently display a classic triad of symptoms-pain, tenderness and temperature sensitivity. Ten treated cases examined with magnetic resonance imaging (MRI) preoperatively are described. All were female with a mean age of 43 years. All except 2 suffered the classic triad of symptoms. The mean duration from onset of symptoms to therapeutic intervention was 7.4 years. MRI depicted the tumours in excellent detail and aided diagnosis in the 4 patients without subungual blue discolouration. The lesions showed a low signal on the T1-weighted image and a high signal on the T2-weighted image. All except 3 were located in the subungual region. All patients underwent surgical excision with pathological confirmation. The postoperative course was smooth and there were no sequelae. High resolution MRI, providing a clear contrast between tumorous and normal tissues, has proved to be a useful non-invasive method for imaging glomus tumours in the hand.
Adolescent↗
Functional MRI of the activated human visual cortex.
We explored the possibility of performing functional magnetic resonance imaging of visual evoked response in the primary visual cortex with a clinical MRI imager of 1.5 tesla. Gradient echo pulse sequence was chosen to acquire the functional image and binocular flash visual stimulation by light-proof goggles containing light emitting diodes was used as the source of cerebral activation. Data processing was performed utilizing direct subtraction for averaged images, correlation coefficient, statistical parametric mapping and matched filter. Of those methods, correlation coefficient and statistic parametric mapping proved to be the methods of choice in our study.
Brain Mapping↗
High-resolution computed tomography in pulmonary lymphangio(leio)myomatosis and pulmonary tuberous sclerosis.
We report two cases where high-resolution computed tomography (HRCT) assisted in the diagnosis of a patient with lymphangioleiomyomatosis and a patient with pulmonary tuberous sclerosis. HRCT was used in both cases where the chest radiographs and conventional computed tomographic scans appeared relatively normal but the conditions were strongly suspected.
Adult↗
Infectious spondylitis: MRI characteristics.
Magnetic resonance imaging (MRI) scans of 24 patients with clinically proven infectious spondylitis were retrospectively evaluated. Evaluation was made of abnormal signal and enhancement patterns within vertebral bodies, intervening disks, and epidural and paraspinal abscesses. The causative organisms included Mycobacterium tuberculosis, fungi and pyogenic bacteria. Staphylococcus aureus was the predominant causative organism among pyogentic bacteria. Decreased signal intensity of vertebral marrow on T1-weighted images was more extensive in pyogenic infections. Multilevel involvement (more than two) was observed in six of the 24 patients. Contiguous multilevel involvement was observed only in patients with tuberculous spondylitis. Noninvolvement of the intervertebral disk space was observed in two patients with pyogenic spondylitis. Epidural abscess was found in 15 patients, most of whom had dense, homogeneous enhancement. Paraspinal abscess was found in 18 patients. Diffuse patchy enhancement without obvious abscess formation in the paraspinal compartment was found in those patients with pyogenic infections. "Rice bodies" were found in paraspinal abscesses in only three patients with tuberculous spondylitis. It was difficult to differentiate candidal from tuberculous spondylitis on MRI. Compared with pyogenic infection, tuberculous spondylitis had a predilection for spinal deformity, subligamentous spread, contiguous multilevel involvement, presence of signal voids in paraspinal abscesses on T2WT and a lesser extent of marrow edema.
Adolescent↗
Magnetic resonance imaging of vertebral compression fractures.
In this study, magnetic resonance imaging (MRI) was used to analyze the signal intensity and vascularity of compression fractures of vertebrae in 74 patients. The possibility of nonunion was assessed according to the specific image findings and clinical presentation. All patients had chronic back pain for more than 3 months and compression fractures of the vertebrae initially demonstrated by plain radiography. Pre-enhanced T1 and T2*-weighted images (*multiplaner gradient recall sequence) and postenhanced MRI were obtained. Images were divided into three categories according to the signal intensity of the fractured vertebrae such as hyperintensity (n = 35), hypointensity (n = 24) on T1-weighted image and necrotic type compression fractures of the vertebrae (n = 15). Of the 15 necrotic-type cases, 13 disclosed "fluid"-containing space at the collapsed vertebrae and two showed "air"-containing space at the vertebral body. We believe that these findings are pathognomonic signs of nonunion of the collapsed vertebrae. Surgical specimens were obtained from the four patients whose vertebrae showed necrosis and granulation tissue. After posterior spinal instrumentation, the collapsed vertebral body regained the height and presence of the open end-plate of the vertebra on postoperative lateral radiography. The superior capabilities of MRI offers useful criteria that make the diagnosis of nonunion in compression fractures of the spine possible. Thus, a space with "fluid" or "air" collection at the anterior aspect of a collapsed vertebra as well as strong enhancement with Gd-DTPA at the posterior aspect of the collapsed vertebra may be considered to be pathognomonic signs of nonunion of the fractured vertebra.
Aged↗
Therapeutic responses to corticosteroids in Graves' ophthalmopathy.
To elucidate the therapeutic responses to corticosteroids and prognostic factors in the treatment of Graves' ophthalmopathy, 23 patients with Graves' ophthalmopathy were treated with intravenous methylprednisolone 0.5 g daily for 3 days, followed by prednisolone 40 mg daily. Dosage was reduced gradually to 10 mg daily over 4 weeks. The symptoms and signs of the eyes were recorded. Orbital computed tomography and urinary glycosaminoglycan excretion testing were performed before treatment. We observed the effectiveness of treatment at 6 months as the endpoint of this study and classified the response as good or poor. We compared the differences in parameters between these two groups. The results showed that 12 (52%) out of 23 patients had a good response, and three (25%) of those with a good response recovered completely. Corticosteroid therapy dramatically improved lacrimation, reduced soreness and congestion of the eyes and ameliorated exophthalmos, lagophthalmos and extraocular muscle movement. Four (36%) of the 11 patients with a poor response had rebound of symptoms and/or signs after the dosage of prednisolone was decreased. Those with a good response were usually younger, and enlargement of the extraocular muscle was also milder than in those with a poor response. This study demonstrated that corticosteroid therapy is effective in Graves' ophthalmopathy and that extraocular muscle size demonstrated by orbital computed tomography is a prognostic factor of therapy.
Adrenal Cortex Hormones↗
Hemorrhage in intracranial epidermoid cyst.
A case of intracranial epidermoid cyst with intracystic hemorrhage is reported. A 63-year-old woman sustained a head injury after a fall; obtundation and ataxia were noted later. Computed tomography revealed a heterogeneous hyperdense lesion in the posterior and middle cranial fossas. Magnetic resonance imaging showed a lesion with increased signal intensity both on T1 and T2 weighted images. Two craniotomies revealed an intracranial epidermoid cyst with about 6 mL of clotted blood. Pathologic study showed hemosiderin-laden macrophages and neovascularity in the cystic wall granulation tissue, which indicated rupture of the cystic wall with intracystic hemorrhage, which later correlated with the diagnostic image findings. The patient tolerated the two operations well and her postoperative course was smooth. She was discharged in good health without obvious neurologic deficits.
Brain Diseases↗
Isolation of protein glycosylation mutants in the fission yeast Schizosaccharomyces pombe.
We have isolated mutants in the fission yeast Schizosaccharomyces pombe that are defective in protein glycosylation. A collection of osmotically sensitive mutants was prepared and screened for glycosylation defects using lectin staining as an assay. Mutants singly defective in four glycoprotein synthesis genes (gps1-4) were isolated, all of which bind less galactose-specific lectin. Acid phosphatase and other glycoproteins from the gps mutants have increased electrophoretic mobility, suggesting that these mutants make glycans of reduced size. N-linked glycan analysis revealed that terminal oligosaccharide modification is defective in the gps1 and gps2 mutants. Both mutants synthesize the Man9GlcNAc2 core glycan but have reduced amounts of larger structures. Modified core glycans from gps1 cells have normal amounts of galactose (Gal) residues, but reduced amounts of Man, consistent with a defect in a Golgi mannosyltransferase in this mutant. In contrast, N-linked oligosaccharides from gps2 mutants have much less Gal than wild type, because of reduced levels of the Gal donor, UDP-Gal. This reduction is caused by decreased activity of UDP-glucose 4-epimerase, which synthesizes UDP-Gal. Neither the gps1 or gps2 mutations are lethal, although the cells grow at reduced rates. These findings suggest that S. pombe cells can survive with incompletely glycosylated cell wall glycoproteins. In particular, these results suggest that Gal, which comprises approximately 30% by weight of cell wall glycoprotein glycans, is not crucial for cell growth or survival.
Acid Phosphatase↗
MRI of meniscus and cruciate ligament tears correlated with arthroscopy.
Findings from magnetic resonance imaging (MRI) studies of 50 knees were retrospectively interpreted. The results were correlated with arthroscopic findings. Multiple pulse sequences were performed including sagittal double-echo, coronal T1-weighted and gradient echo, axial gradient echo or fat suppression imaging. Three-dimensional MRI was performed if there was a high suspicion of a tear of the anterior cruciate ligament. The individual positive predictive value, sensitivity, specificity and accuracy were calculated from the comparison between MRI and arthroscopic findings of the menisci, anterior cruciate ligament and posterior cruciate ligament. The following results were obtained: 1) Tears of the medial meniscus-positive predictive value, 72%; sensitivity, 87%; specificity, 86%; and accuracy, 86%. 2) Tears of the lateral meniscus-positive predictive value, 85%; sensitivity, 85%; specificity, 90%; and accuracy, 88%. 3) Tears of the anterior cruciate ligament-positive predictive value, 88%; sensitivity, 95%; specificity, 89%; and accuracy, 92%. 4) Tears of the posterior cruciate ligament-positive predictive value, 100%; sensitivity, 100%; specificity, 100%; and accuracy, 100%. It is concluded that MRI is a noninvasive and accurate method for detecting the internal derangement of the knee.
Adolescent↗
MRI appearance of spinal lesions: metastatic tumors or infections?
Three patients with pathologically verified spinal osteomyelitis and another three with metastatic tumors of the spine were investigated. MRI of th spine of four patients showed several unusual findings. The preservation of intervertebral discs and endplates did not predict accurately the diagnosis of either infections or tumors. The "pepper and salt" appearing feature may also occur in a metastatic tumor. Plain radiographs, CT, and radioisotope bone scans were less sensitive than MRI to disclose the lesions. In cases of osteomyelitis, the systemic sources of infections were frequently not found, and the responsible microorganisms could not be identified even from the surgical specimens of two patients. However, mycobacterium tuberculosis was found in the surgical specimen of a patient with cervical spinal lesion whose MRI was indistinguishable from a metastatic tumor. Surgicopathological diagnosis was therefore crucial and mandatory in these instances.
Adult↗
Anomalous origin of the posterior inferior cerebellar artery from the pre-cavernous portion of the internal carotid artery--a primitive trigeminal artery variant.
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Adult↗
Relationship of eye movement to computed tomographic findings in patients with Graves' ophthalmopathy.
To elucidate the relationship between eye movement and computed tomographic findings, 101 patients with Graves' ophthalmology were studied. Eye movements were scaled 0 to 3 according to movability. Extraocular muscle width and area were calculated from the largest portion of each muscle from the orbital coronal CT sections. Muscle widths were measured manually and muscle areas were calculated by a digitizer. The width and area of each rectus muscle were significantly correlated with limitation of eye movement. The muscle widths and areas were also significantly correlated to each other (r = 0.91 to 0.77, p < 0.001). Limitations of supraduction and abduction from enlargement of the inferior and medial rectus muscles were the most common clinical findings (46.5% and 39.6%, respectively). In conclusion, this study establishes a relationship between limitation of eye movement and extraocular muscle enlargement. Calculation of the width from the largest portion of the muscle manually from orbital coronal section is a simple method for clinical assessment of the severity of extraocular muscle involvement.
Adolescent↗
Magnetic resonance imaging of rotator cuff lesions.
The purpose of this study was to evaluate the diagnostic performance of magnetic resonance imaging (MRI) in rotator cuff diseases. Forty consecutive patients studied by MRI from September 1990 to September 1992 were included in the study. MRI was performed on a 1.5 tesla MR scanner. Each MRI study was reviewed by two radiologists experienced in rotator cuff tendons. The MRI finding was compared with the surgical result. MRI sensitivity for all tears (partial and complete) was 1.0 (22/22), specificity 0.89 (16/18), accuracy rate 0.95 (38/40), and the predictive value 0.92 (22/24). Signal changes of the rotator cuff tendon (primary signs) were the most reliable criteria in diagnosis of the tear. Changes of subacromial and subdeltoid fat planes and bursa (secondary signs) were complimentary when primary signs were indeterminant. The direction of the long axis of abnormal signal intensity in the rotator cuff tendon may be a good indicator when differentiating tears from tendinitis. We conclude that MRI shows excellent performance in the determination of the presence or absence of a rotator cuff tear.
Adolescent↗
Agenesis of the internal carotid artery associated with neurofibromatosis type II.
We report a case of agenesis of the internal carotid artery associated with neurofibromatosis type II. Common carotid arteriograms showed no visualization of the internal carotid artery. CT revealed absence of the corresponding carotid canal. MR documented absence of the internal carotid artery in the cavernous sinus.
Adolescent↗
Glycoprotein recycling to the galactosyltransferase compartment of the Golgi complex.
The recycling of plasma membrane glycoproteins to the Golgi complex is well established, but it is not clear which Golgi subcompartments receive this traffic. To date, recycling into the trans-Golgi compartment that contains sialyltransferase and the early Golgi region that contains alpha-mannosidase I has been demonstrated. However, transport into other Golgi compartments has not been reported. In this study we tested the return of cell surface glycoproteins to the Golgi galactosyltransferase compartment using the ldlD mutant of Chinese hamster ovary cells. The cation-independent mannose 6-phosphate/insulin-like growth factor-II receptor recycled through this Golgi region with a half-time of 4 h and was transported to the sialyltransferase compartment as well. Because galactosyltransferase and sialyltransferases are probably located in different trans-Golgi regions in Chinese hamster ovary cells, these results suggest that the two compartments each receive recycling traffic or that recycling glycoproteins enter one region and are then transported to the other. The extent of cell surface protein recycling through the galactosyltransferase compartment was also studied. At least 10 different glycoproteins were transported from the cell surface to this Golgi region. Moreover, our results suggest that recycling glycoproteins make up 12-25% of the flux of cell surface glycoproteins through the Golgi galactosyltransferase compartment; the balance is comprised of newly made glycoproteins.
Animals↗
Evaluation of hip disorders by radiography, radionuclide scanning and magnetic resonance imaging.
Thirty-six hips were studied because of significant hip pain. Radiography of the hip and bone scintigraphy showed subtle changes. Magnetic resonance imaging (MRI) was performed using a 1.5 Tesla superconductive unit. All MRI findings were confirmed by surgical or pathologic results. Twenty-nine hips had a single lesion, including: infection (one), fracture (eight), avascular necrosis of the femur(two), or contralateral hip (four), transient osteoporosis (six), osteoporosis (one), post-irradiation myositis (one), metastasis (four), and synovitis (two). Twenty-six lesions (89.6%) appeared normal on the radiographs of the hip, while three lesions (10.4%) showed only osteoporotic change. Another seven hips had more than one lesion, including: avascular necrosis and fracture (four), fracture foci (two), and metastasis and fracture (two). Radiography of the hip showed either a negative finding or detected only a single lesion, missing other important pathologic foci. MRI is extremely sensitive to alterations in the bone marrow that may represent pathology occult to plain radiography and bone scintigraphy of the hips. For diagnosis and treatment planning, MRI of the hips should be performed early in patients with persistent pain and negative radiography findings.
Acetabulum↗
MR patterns of rotator cuff and labral lesions: comparison between low-field and high-field images.
Eighteen people (10 men, 8 women) were examined on a 0.3-T (low-field) imager with T1-weighted axial and coronal images and either axial or coronal T2-weighted images. Thirty-two people (22 men, 10 women) were examined on a 1.5-T (high-field) imager with axial T1-weighted images and coronal, sagittal dual-echo images. Rotator cuff lesions were diagnosed by the following findings: abnormal signal in the tendon, irregularity or discontinuity at the musculo-tendinous junction, or muscle abnormality. Glenoid labrum tears were considered if one or more of the following criteria were present: labral deformity of unusual size, focal defect, amputation or displacement with fluid, or capsular stripping. Comparison between the high-field and low-field MR images in the evaluation of rotator cuff lesions suggests that the high-field imager is better than the low-field imager in the differentiation of tendinitis from tears, in the confirmation of bursitis and in detection of subscapularis lesions. A higher contrast-to-noise ratio (CNR), less time consumption, and more section planes (especially, sagittal sections) appear to be the main reasons for this. As far as labral lesions are concerned, the performances of the high-field imagers and low-field imagers were almost equal. The artifact of greater chemical shift with a high-field imager would more or less, we assume, degrade the better CNR achievable in the diagnosis of labral lesions.
Adolescent↗