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Biomedical subjects

C T Su

Publications and source records attributed to C T Su.

At least 55 records · Page 3Linked to original sources
PubMed1994

Findings of anomalous pulmonary venous return using MRI.

This study represents a preliminary retrospective assessment of the value of spin-echo magnetic resonance imaging (MRI) in detecting and describing total or partial anomalous pulmonary venous return (APVR). MRI was performed in 21 cases of APVR; orthogonal planes were used in all. Of the 21 cases, 19 were classified as total APVR (TAPVR) and two were partial APVR (PAPVR). Of the 19 cases of TAPVR, seven supracardiac, nine cardiac, one infracardiac and two mixed type were noted. The detection rate of each pulmonary vein combined in all three planes was 57% in the right superior pulmonary vein (RSPV), 62% in the left superior pulmonary vein (LSPV), 76% in the right inferior pulmonary vein (RIPV), and 86% in the left inferior pulmonary vein (LIPV). The axial plane was most effective (RSPV: 38%; LSPV: 52%; RIPV: 71%; LIPV: 81%). The coronal plane offered a better detection rate than the axial plane in RSPV (43%) and additional information of bronchial and visceral situs. Imaging of the combined axial and coronal planes was sufficient to evaluate each individual pulmonary vein. The sagittal plane gave no additional information in this respect. Accurate identification of pulmonary venous confluence and anomalous pulmonary venous channel was 95% (20/21). Limitation of echocardiography and and angiocardiography makes cardiac MRI important in assessing pulmonary vein and pulmonary venous confluence. It obviates the need for invasive angiocardiography and is an important supplement to an inadequate echo.

Adolescent↗
PubMed1994

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↗
PubMed1993

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↗
PubMed1993

[Computed tomography of gastric carcinoma using water as a contrast agent].

To overcome the problem of poor mixing of gastrointestinal tract contents with a diluted iodinated contrast agent in abdominal computed tomography, pure water was adopted as an oral contrast agent. In 25 cases of clinically suspected gastric carcinoma, a subsequent pathological examination revealed six cases of early gastric cancer and 19 cases of advanced gastric cancer. We performed CT of the stomach using the following revised procedure: patients were given 600-1000 mL of water by mouth after an intramuscular dose of Buscopan to distend and immobilize the stomach. Gastric mucosal enhancement and the poorer enhanced submucosal layer were demonstrated by a bolus intravenous injection of iodine-containing contrast medium using an automatic injector synchronized with the CT machine. Based on abnormal gastric wall thickening and the abnormal mural enhancement patterns, an accuracy of 96% was attained in differentiating early gastric cancer from advanced gastric cancer, but the detection rates for extragastric invasion, gastric ulcers and lymphadenopathy were 67%, 43% and 63%, respectively. CT staging of gastric cancer was 72%, and was especially accurate for stages I and IV. Water as oral contrast agent for CT of the GI tract was readily accepted by patients and caused no side effects. Using water as an oral contrast for gastric CT is of great help in staging gastric cancer.

Adult↗
PubMed1993

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↗
PubMed1992

Correlation between left ventricular systolic function and dipyridamole thallium SPECT redistribution patterns in coronary artery disease.

The dipyridamole thallium-201 single photon emission computed tomography (SPECT) and resting gated blood pool ventriculography were sequentially conducted in 31 consecutive patients with angiographically proven coronary artery disease. The functional significance of various thallium redistribution patterns was assessed. The patients with an entirely complete (CR) or partial (PR) redistribution pattern had a higher global left ventricular ejection fraction than those with combined PR and no redistribution (NR), while patients with an entirely CR pattern did not have a statistically better ejection fraction than those with PR. Furthermore, myocardial segments with normal perfusion (N) and those with CR or PR had a higher regional ejection fraction than those with NR in the infero-apical area and the septal area. The regional ejection fraction was statistically higher in patients with CR than in those with PR in the septal area and higher, though not statistically significant, in the infero-apical area. The functional difference between groups with N and CR was not significant. Thus, we conclude that the redistribution patterns of dipyridamole thallium SPECT are closely correlated with systole function. Myocardium, in the presence of redistribution, will have a better functional performance in coronary artery disease.

Adult↗
PubMed1992

Multiplanar gradient recalled images of the knee: comparison of different flip angles and echo times.

To determine the most appropriate combination of echo time (TE) and flip angle in gradient echo images of the knee, the authors used different TEs (10, 20 and 30 msec) and flip angles (10, 30, 50, 70, 90, 120 and 150 degrees) to perform a systematic study of MRI on 10 volunteer knees. Contrast-to-noise ratios of cartilage-fat, fluid-cartilage, fluid-fat and fluid-ligament were calculated and compared. Images with a 30-degree flip angle combined with 20 msec of TE were found to have the best contrast-to-noise ratios in both objective data analysis and subjective observation. Hyaline cartilage of the knee was hyperintense and was well delineated on this pulse sequence, appearing distinct in contrast to the intra-articular fluid. It is concluded that this T2-weighted gradient echo pulse sequence is an alternative to conventional spin echo T2-weighted imaging of the knee.

Echo-Planar Imaging↗
PubMed1992

Exercise thallium-201 tomographic scintigraphy in the diagnosis of coronary artery disease: emphasis on the effect of exercise level.

Exercise thallium-201 imaging using single-photon emission computed tomography (SPECT) was evaluated in 154 patients with angiographically documented coronary artery disease (CAD) and in 25 normal subjects. Of the 154 patients with CAD, 134 (87%) had abnormal thallium images. By contrast, only 77 (50%) patients had ischemic ST-segment depression (p < 0.001). Among 25 normal subjects, 20 had normal exercise SPECT images. The specificity of exercise SPECT imaging (80% or 20/25) in excluding patients with CAD was not significantly higher than that of exercise electrocardiography (76% or 19/25). For the detection of individual vessel involvement by analysis of territories of perfusion abnormalities, the sensitivity and specificity of exercise SPECT were 72% and 96% for the left anterior descending, 78% and 85% for the right coronary, and 47% and 98% for the left circumflex artery. Ninety (group 1) of the 154 patients with CAD achieved adequate exercise end points (ischemic ST-segment depression or > 85% of maximal predicted heart rate) and 64 (group 2) did not. Exercise SPECT showed significantly more perfusion abnormalities in group 1 than in group 2 (96% vs 75%, p < 0.001). We conclude that: (1) exercise SPECT thallium imaging is more sensitive than exercise electrocardiography for detecting patients with CAD; (2) the sensitivity of the test is affected by the level of exercise; and (3) it is valuable in the identification of individual vessel involvement.

Coronary Disease↗
PubMed1992

Predictive value of total body bone mineral density for vertebral fractures in elderly women. Geriatric Study Group.

In a general population-based geriatric disease survey in Taipei City, the bone mineral density (BMD) of 58 women over 65 years of age was measured for the whole body, lumbar spine (L2-L4), and proximal femurs using a 153Gd based dual photon absorptiometer. These women were found to have at least one vertebral fracture. The results showed that the BMD readings of both the lumbar spine (L2-L4) (mean Z score +/- SEM = 0.05 +/- 0.12) and the femoral neck (mean Z score +/- SEM = -0.20 +/- 0.10) were not statistically different from those of age-matched controls. However, the total body BMD in these 58 patients was significantly lower than in the normal controls (mean Z score +/- SEM = -1.07 +/- 0.10, p < 0.0001). In the normal control group (N = 69, age 50-85), there was a significant linear correlation between the total body and lumbar BMD (r = 0.81, p < 0.0001). This correlation was not found in the 58 women with vertebral fractures (r = 0.14, NS). Our results suggest that geriatric women with vertebral fractures are more osteoporotic than normal aged women, even though they have a relatively mild degree of spinal osteoporosis. But, because of age-associated degenerative changes or other factors, conventional anteroposterior lumbar BMD measurements cannot detect the difference. The total body BMD readings, but not the lumbar or femoral neck BMD readings, seem to be less affected by these local changes and may provide a better discriminative or predictive value for vertebral fracture in this particular age group.

Aged↗
PubMed1991

Refined crystal structures of "aged" and "non-aged" organophosphoryl conjugates of gamma-chymotrypsin.

"Aged" organophosphoryl conjugates of serine hydrolases differ from the corresponding "non-aged" conjugates in their striking resistance to nucleophilic reactivation. The refined X-ray structures of "aged" and "non-aged" organophosphoryl conjugates of gamma-chymotrypsin were compared in order to understand the molecular basis for this resistance of "aged" conjugates. "Aged" and "non-aged" crystalline organophosphoryl-gamma-chymotrypsin conjugates were obtained by prolonged soaking of native gamma-chymotrypsin crystals with appropriate organophosphates. Thus, a representative "non-aged" conjugate, diethylphosphoryl-gamma-chymotrypsin, was obtained by soaking native crystals with paraoxon (diethyl-p-nitrophenyl phosphate), and a closely related "aged" conjugate, monoisopropyl-gamma-chymotrypsin, was obtained by soaking with diisopropylphosphorofluoridate. In both crystalline conjugates, the refined structures clearly reveal a high occupancy of the active site by the appropriate organophosphoryl moiety within covalent bonding distance of Ser195 O gamma. Whereas in the "non-aged" conjugate both ethyl groups can be visualized clearly, in the putative "aged" conjugate, as expected, only one isopropyl group is present. There is virtually no difference between the "aged" and "non-aged" conjugates either with respect to the conformation of the polypeptide backbone as a whole or with respect to the positioning of the side-chains within the active site. In the "aged" conjugate, however, close proximity (2.6 A) of the negatively charged phosphate oxygen atom of the dealkylated organophosphoryl group to His57 N epsilon 2 indicates the presence of a salt bridge between these two moieties. In contrast, in the "non-aged" conjugate the DEP moiety retains its two alkyl groups; thus, lacking a negative oxygen atom, it does not enter into such a charge-charge interaction and its nearest oxygen atom is 3.6 A away from His57 N epsilon 2. It is suggested that steric constraints imposed by the salt bridge in the "aged" conjugate lie at the basis of its resistance to reactivation.

Alkylation↗
PubMed1991

Gamma-chymotrypsin is a complex of alpha-chymotrypsin with its own autolysis products.

The determination of three separate gamma-chymotrypsin structures at different temperatures and resolutions confirmed the presence of electron density in the active site, which could be interpreted as an oligopeptide as had previously been suggested by Dixon and Matthews [(1989) Biochemistry 28, 7033-7038]. HPLC analyses of the enzyme before and after crystallization demonstrated the presence of a wide variety of oligopeptides in the redissolved crystal, most with COOH-terminal aromatic residues, as expected of the products of chymotrypsin cleavage, which appeared to arise from extensive autolysis of the enzyme under the crystallization conditions. The refined structures agree well with the conformation of both gamma-chymotrypsin and alpha-chymotrypsin. The electron density in the active site is thus interpreted as arising from a repertoire of autolysed oligopeptides produced concomitantly with crystallization. The COOH-terminal carbons of the polypeptide(s) display short contact distances (1.97, 2.47, and 2.13 A, respectively) to Ser195 O gamma in all three refined structures, but the electron density is not continuous between these two atoms in any of them. This suggests that some sequences are covalently bound as enzyme intermediates while others are noncovalently bound as enzyme-product complexes.

Amino Acid Sequence↗
PubMed1991

Decreased bone mineral density in patients with prolonged thyrotoxicosis before and after treatment.

To investigate the effects of prolonged thyrotoxicosis, we measured the bone mineral densities (BMD) of 24 untreated patients who had suffered from symptoms of thyrotoxicosis for at least 1 year. We also recruited 116 healthy Chinese women residing in the Taipei area as normal controls. The BMDs of these 24 patients for the whole body skeleton, lumbar spine, femoral neck, greater trochanter and Ward's triangle were all significantly lower than those of normal controls (one sample t-test, two-tailed alternative). Older patients had lower absolute values and a trend towards more severe bone loss, which was most significant at the femoral trochanter and Ward's triangle (p less than or equal to 0.05). The decrease in BMD was more pronounced in the vertebral bodies than in the proximal femur for all patients, implying predominantly trabecular bone loss in this disease. The BMDs of 10 patients were reevaluated 1 year after successful medical treatment. These 10 patients had remained euthyroid for 1 year with antithyroid drugs and showed a small, but significant, improvement in their BMDs at the lumbar spine and the proximal femur on reevaluation. However, the recovery was far from complete. Our findings suggest that thyrotoxicosis causes a remarkable loss of bone mineral, which cannot be compensated for after 1 year of successful treatment. Thus, early diagnosis and therapeutic intervention are important for preventing osteoporotic fractures, especially in elderly patients.

Adult↗
PubMed1991

Age-related changes in vitamin D metabolites, osteocalcin, alkaline phosphatase and parathyrin in normal Chinese women in Taipei.

To evaluate the age-related changes in the bone remodeling rate, the vitamin D status, and parathyroid function of healthy Chinese women, we selected two serum markers of bone turnover, osteocalcin and alkaline phosphatase (ALP). These markers as well as vitamin D metabolites and parathyrin (parathyroid hormone, PTH) were tested in healthy Chinese female volunteers aged 18 to 80 years residing in the Taipei urban area. The results showed no significant change with aging in the 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D) and immunoreactive c-terminal PTH (i-cPTH) serum levels. However, there was a trend towards lower 25(OH)D levels at the two extremes of age. The serum levels of 1,25(OH)2D and i-cPTH were comparable with reports of other countries. The serum 25(OH)D levels of our subjects were in general lower than those reported in U.S. white women, but similar to those of European women. The serum osteocalcin levels showed a triphasic change: high in early adulthood, decreasing during the 4th decade of life and then increasing continuously until age 70. After age 70, a decreasing trend was again seen. The serum ALP levels showed a continuous increase from the 3rd to the 8th decade of life. All of the subjects had their bone mineral density (BMD) measured. Linear or polynominal regression analysis as well as multiple regression analysis failed to show a significant correlation between the serum parameters and the BMD measurements at various sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Solid and papillary neoplasm of the pancreas: report of three cases.

We report 3 cases of solid and papillary neoplasm of the pancreas, which is a rare pancreatic tumor with distinct clinicopathologic characteristics. Sonographic, computed tomographic (CT) and gross pathologic findings of these 3 patients were obtained and compared. The tumors had a smooth, enhanced capsule and variable internal architecture. Two of the tumors appeared to be of the heterogeneous soft tissue density type, while one of the tumors was of the mixed solid and cystic type. Because the CT appearance of this tumor is subject to variation, it should be differentiated from other pancreatic lesions with variable CT appearances. Several CT features such as soft tissue density of the mass in a precontrast study, a well-enhanced capsule and the absence of pancreatic or biliary duct dilatation, as well as the characteristic young-female predilection, may aid in a correct diagnosis before surgery.

Adolescent↗
PubMed1990

Diagnosis of atretic prolonged obstructive jaundice; technetium 99m hepatolite excretion study.

Since 1982 we have developed a diagnostic method for differentiation between atretic prolonged obstructive jaundice (biliary atresia) and nonatretic prolonged obstructive jaundice in a neonate. The first report was presented at the Fukuoka Meeting in 1983. Analysis of duodenal juice (excretion test of intravenous injected hepatolite into the duodenum) has proved to be extremely reliable to differentiate biliary atresia from nonatretic prolonged obstructive jaundice. The major diagnostic features of the study are (1) biliary tract to bowel transit of radiotracer, and (2) observation on color of duodenal juice. Diagnostic accuracy was 98.4%. It is time-saving, requiring only 6 hours, noninvasive, and simple.

Bile Acids and Salts↗
PubMed1990

Diagnosis of cardiac metastasis by computed tomography: report of 5 cases.

Five patients with underlying malignancy were detected antemortemly to have cardiac metastasis by post-enhanced CT scanning. The most common presentations were abnormal heart sounds, electrocardiographic changes and inexplicable heart failure; which lead us to suspect cardiac metastasis. One patient had an "engorged azygous knob" on his chest x-ray film, which provided a clue to possible cardiac metastasis. All of these patients had tumor thrombi in their large tributary veins in addition to the primary tumors. Thus, we advanced the CT scan to the cardiac region and cardiac metastases were, therefore, diagnosed. The tumor thrombi in the large tributary veins seemed to be the source for intracardiac spreading. Cardiac angiographies were performed in 3 patients and confirmed the diagnosis. We conclude that post-enhanced CT scanning is useful in the diagnosis of cardiac metastasis and the presence of tumor thrombi in the large tributary vein is an early sign of cardiac involvement.

Adult↗