Biomedical subjects

Kuang-Tao Yang

Publications and source records attributed to Kuang-Tao Yang.

5 recordsLinked to original sources

PubMed2005

Incremental value of ischemic stunning on the detection of severe and extensive coronary artery disease in dipyridamole Tl-201 gated myocardial perfusion imaging.

The sensitivity of nuclear myocardial perfusion imaging in detecting coronary artery disease is high. However, false-negative results may be encountered if all the myocardial territories were uniformly affected. Ischemic stunning after dipyridamole-stress on gated SPECT may be an indicator of severe and extensive coronary artery disease, and can help the interpretation of borderline perfusion images and the elimination of false-negatives secondary to relatively balanced lesions in three-vessel disease.

Aged↗

PubMed2005

Performance of thallium-201 electrocardiography-gated myocardial perfusion single photon emission computed tomography to assess left ventricular function.

This study evaluated the performance of gated single photon emission computed tomography (SPECT) with thallium-201 (201Tl) in assessing left ventricular ejection fraction (LVEF), end-diastolic volume (EDV), and end-systolic volume (ESV) in Taiwanese by determining repeatability and correlation with two-dimensional (2D) echocardiography. A total of 18 patients underwent two sequential gated SPECT acquisitions within 30 minutes in the resting state to assess repeatability. Another 28 patients who underwent gated SPECT and 2D echocardiography within 7 days were included for comparison. The two sequential measurements were well correlated with respect to LVEF, EDV, and ESV (r = 0.97, 0.95, and 0.97, respectively, all p < 0.0001). Bland-Altman analysis revealed that two standard deviations of the absolute difference between the two sequential measurements for LVEF, EDV, and ESV were 6.4%, 16.8 mL, and 8.6 mL, respectively. For LVEF, EDV, and ESV, correlations between redistribution 201Tl-gated SPECT and echocardiography were also excellent (all r = 0.83, p < 0.0001). LVEF was similar with 201Tl-gated SPECT and echocardiography, but EDV and ESV were significantly higher with echocardiography (p < 0.05). Our study revealed that 201Tl-gated SPECT has high repeatability and excellent correlation with echocardiography for the assessment of LVEF and volumes in Taiwanese. These results support the clinical application of gated SPECT in routine 201Tl myocardial perfusion imaging in Taiwanese.

Adult↗

PubMed2005

Synchronous parathyroid and papillary thyroid carcinoma.

Concomitant thyroid disease is not unusual among patients with primary hyperparathyroidism. However, the simultaneous occurrence of parathyroid and thyroid carcinoma is extremely rare. We report a 38-year-old man with primary hyperparathyroidism who presented with osteitis fibrosa cystica complicated with pathologic femoral neck fracture. Preoperative investigation for exclusion of multiple endocrine neoplasia did not find evidence of medullary thyroid carcinoma or pheochromocytoma, but imaging studies revealed the presence of nodules in the right lobe and a parathyroid lesion over the left inferior pole of the thyroid gland. Total thyroidectomy, left parathyroidectomy, and bipolar hemiarthroplasty of the left hip were then performed simultaneously. The resected specimens were pathologically identified as papillary thyroid carcinoma and parathyroid carcinoma, respectively. After the operation, 131I ablation therapy was administered at a dose of 120 mCi. Additional doses of 30 mCi were given yearly as serum thyroglobulin level became elevated. Serum calcium level remained normal during yearly follow-up. Although parathyroid carcinoma is an uncommon cause of parathyroid hormone-dependent hypercalcemia, it should nonetheless be given due consideration because its surgical approach differs from that of parathyroid adenoma. As the coexistence of parathyroid and non-medullary thyroid carcinoma has previously been reported, the possibility of both malignancies must also be considered in the setting of primary hyperparathyroidism with thyroid nodules. If confirmed with preoperative parathyroid scintigraphic and other laboratory studies, an optimal outcome may be achieved with complete resection of both tumors at the time of initial operation, followed by adjunctive therapy.

Adult↗

PubMedDate not supplied

Worsening of left ventricular ejection fraction induced by dipyridamole on Tl-201 gated myocardial perfusion imaging predicts significant coronary artery disease.

BACKGROUND: Vasodilator stress on myocardial perfusion imaging has been found to induce ischemic stunning, which may present as transient worsening of left ventricular ejection fraction (LVEF) or regional wall motion abnormality. This study aimed to evaluate the significance of stress-induced worsening of LVEF in the diagnosis of coronary artery disease (CAD) on dipyridamole thallium 201 gated single photon emission computed tomography (SPECT). METHODS AND RESULTS: The study included 126 patients who underwent dipyridamole Tl-201 gated SPECT and coronary angiography within 3 months. Poststress and 4-hour rest images were obtained, and LVEF was calculated by use of automated software (QGS 3.0). A decrease in LVEF of 6% or greater from rest to poststress was considered significant, and this threshold was determined by the serial reproducibility assessment of Tl-201 gated SPECT. If worsening of LVEF was used as the criterion for detecting significant CAD (> or = 70% coronary stenoses in > or = 1 vessel), the sensitivity, specificity, positive predictive value, and negative predictive value were 35%, 93%, 90%, and 44%, respectively. CONCLUSION: Dipyridamole-induced worsening of LVEF, as shown by Tl-201 gated SPECT, is a valuable nonperfusion marker of significant CAD. Although the sensitivity of LVEF worsening in detecting significant CAD is only 35%, the specificity is as high as 93%.

Aged↗

PubMedDate not supplied

Relationship of transient ischemic dilation in dipyridamole myocardial perfusion imaging and stress-induced changes of functional parameters evaluated by Tl-201 gated SPECT.

BACKGROUND: This study assessed whether transient ischemic dilation (TID) of the left ventricle is related to ischemic stunning, manifested by stress-induced decrease of left ventricular ejection fraction (LVEF) and worsening of wall motion, by use of dipyridamole-stress and redistribution thallium 201 gated single photon emission computed tomography (SPECT). METHODS AND RESULTS: Ninety-two consecutive patients undergoing dipyridamole Tl-201 gated SPECT were included. Patients with a TID ratio in the highest quartile were defined as having TID. In patients with TID, end-diastolic volume (EDV) and end-systolic volume (ESV) were both significantly greater on dipyridamole-stress images than on redistribution images (P < .001). The degree of enlargement was much greater for ESV than EDV. In patients without TID, EDV and ESV were both decreased after stress (P < .001). Patients with TID had a lower mean LVEF on dipyridamole-stress images than on redistribution images (P < .001). Patients without TID had a higher mean LVEF on dipyridamole-stress images than on redistribution images (P < .001). Patients with TID had a significant worsening of global wall motion on dipyridamole-stress images than on redistribution images (P < .001), but patients without TID did not. CONCLUSION: TID was significantly correlated with ischemic stunning, and the enlargement of ESV was an important factor resulting in TID.

Aged↗